Head and Neck Diseases by Alexandros G.Sfakianakis: 08/09/17

Τετάρτη 9 Αυγούστου 2017

Upper airway surgery for obstructive sleep apnea reduces blood pressure

Objectives/Hypothesis

To evaluate if upper airway surgery reduces blood pressure in patients with obstructive sleep apnea (OSA).

Study Design

Prospective series.

Methods

A prospective series of 112 consecutive OSA patients with hypertension (HTN). All patients were > 18 years old, respiratory disturbance index >5, all levels of apnea-hypopnea index (AHI), with a history of HTN treated with medication for at least 6 months. Surgical procedures included septoplasty, turbinate reduction, palate surgery, and tongue base reduction.

Results

There were 92 men and 20 women, with a mean age of 48.6 years, mean body mass index (BMI) was 27.5 (range, 19.7–34.7). Mean follow-up was 16.1 months. The mean preoperative AHI was 32.6 (range, 1.2–104), with the mean lowest oxygen saturation (LSAT) of 79.9% (range, 52%–93%). The mean adjusted preoperative and postoperative systolic blood pressure (SBP) was reduced from 146 ± 15.3 mm Hg to 122 ± 12.5 mm Hg (P < .001), and diastolic blood pressure (DBP) was reduced from 91 ± 10.2 mm Hg to 76 ± 7.8 mm Hg (P < .001). There was a decrease in overall BMI from 27.5 ± 3.6 to 25.5 ± 3.0 (P < .001); however, based on multivariate analysis, the reduction in SBP and DBP was not affected by this BMI reduction. Fifty-eight patients (51.8%) did not require their antihypertensive after surgery. There was poor correlation noted between HTN with AHI, LSAT, and oxygen duration <90%.

Conclusions

Upper airway surgery does reduce SBP and DBP in patients with OSA.

Level of Evidence

4. Laryngoscope, 2017

http://ift.tt/2wKJoBk

Upper airway surgery for obstructive sleep apnea reduces blood pressure

Objectives/Hypothesis

To evaluate if upper airway surgery reduces blood pressure in patients with obstructive sleep apnea (OSA).

Study Design

Prospective series.

Methods

Results

Conclusions

Upper airway surgery does reduce SBP and DBP in patients with OSA.

Level of Evidence

4. Laryngoscope, 2017

http://ift.tt/2wKJoBk

Beyond Genomics - Targeting the Epigenome in Diffuse Large B-Cell Lymphoma

Publication date: Available online 9 August 2017
Source:Cancer Treatment Reviews
Author(s): Andrea Kühnl, David Cunningham, Ian Chau
After decades of intense research on genetic alterations in cancer and successful implementation of genetically-based targeted therapies, the field of cancer epigenetics is only beginning to be fully recognized. The discovery of frequent mutations in genes modifying the epigenome in diffuse large B-cell lymphoma (DLBCL) has highlighted the outstanding role of epigenetic deregulation in this disease. Identification of epigenetically-driven DLBCL subgroups and development of novel epigenetic drugs have rapidly advanced. However, further insights are needed into the biological consequences of epigenetic alterations and the possibility of restoring the aberrant epigenome with specific therapies to bring this treatment concept further into clinical practice. This review will summarize the main epigenetic changes found in DLBCL and their potential for precision medicine approaches.

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Novel method of extracting motion from natural movies

Publication date: Available online 9 August 2017
Source:Journal of Neuroscience Methods
Author(s): Wataru Suzuki, Noritaka Ichinohe, Toshiki Tani, Taku Hayami, Naohisa Miyakawa, Satoshi Watanabe, Hiroshige Takeichi
BackgroundThe visual system in primates can be segregated into motion and shape pathways. Interaction occurs at multiple stages along these pathways. Processing of shape-from-motion and biological motion is considered to be a higher-order integration process involving motion and shape information. However, relatively limited types of stimuli have been used in previous studies on these integration processes.New methodWe propose a new algorithm to extract object motion information from natural movies and to move random dots in accordance with the information. The object motion information is extracted by estimating the dynamics of local normal vectors of the image intensity projected onto the x-y plane of the movie.ResultsAn electrophysiological experiment on two adult common marmoset monkeys (Callithrix jacchus) showed that the natural and random dot movies generated with this new algorithm yielded comparable neural responses in the middle temporal visual area.Comparison with existing methodsIn principle, this algorithm provided random dot motion stimuli containing shape information for arbitrary natural movies. This new method is expected to expand the neurophysiological and psychophysical experimental protocols to elucidate the integration processing of motion and shape information in biological systems.ConclusionsThe novel algorithm proposed here was effective in extracting object motion information from natural movies and provided new motion stimuli to investigate higher-order motion information processing.

http://ift.tt/2uIqWb6

A novel method for sex estimation using 3D computed tomography models of tooth roots: A volumetric analysis

Publication date: November 2017
Source:Archives of Oral Biology, Volume 83
Author(s): Seyedeh M. Kazzazi, Elena F. Kranioti
Advances in technologies such as computed tomography (CT) scanning have allowed for further examination of dental sexual dimorphism in modern and archaeological populations.

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Issue Information - Contents

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Cover Image

The cover image, by Jacqui Allen et al., is based on the Original Article Assessment of videofluoroscopic swallow study findings before and after cricopharyngeal myotomy, DOI: 10.1002/hed.24846.

http://ift.tt/2wvM86d

Cover Image

The cover image, by Jacqui Allen et al., is based on the Original Article Assessment of videofluoroscopic swallow study findings before and after cricopharyngeal myotomy, DOI: 10.1002/hed.24846.

http://ift.tt/2wvM86d

Dissipation kinetics, pre-harvest residue limits, and hazard quotient assessments of pesticides flubendiamide and fluopicolide in Korean melon ( Cucumis melo L. var. makuwa ) grown under regulated conditions in plastic greenhouses

Abstract

The dissipation kinetics, pre-harvest residue limits, and hazard quotient (HQ) assessments of the pesticides flubendiamide and fluopicolide were conducted for Korean melon (Cucumis melo L. var. makuwa) cultivated at two different sites. A single extraction and cleanup procedure was carried out using acetone (partitioned with dichloromethane) and amino solid-phase extraction cartridges, respectively. Residue analysis was performed by HPLC with ultraviolet detection. Both pesticides showed excellent linearity with correlation coefficients of 0.9999 and 0.9996 for flubendiamide and fluopicolide, respectively. The accuracy (expressed as recovery %) at three spiking levels was 92.0–103.6 and 82.8–105.3%, and the precision (expressed as relative standard deviation) was 1.7–3.4 and 2.7–5.3% for flubendiamide and fluopicolide, respectively. The initial residues of flubendiamide/fluopicolide were 0.326/0.376 and 0.206/0.298 mg/kg at sites 1 and 2, respectively. These amounts were substantially lower than the maximum residue limits (MRLs = 1 and 0.5 mg/kg for flubendiamide and fluopicolide, respectively) established by the Korean Ministry of Food and Drug Safety. The half-lives of flubendiamide were 5.8 and 6.5 days, and those of fluopicolide were 6.7 and 9.1 days at sites 1 and 2, respectively. The shorter half-lives were attributed to seasonal variations (higher temperatures) and enzymatic and metabolic profiling. The risk assessment HQs of flubendiamide were 0.217/0.249 on day 0, which decreased to 0.102/0.168 on day 5, and to 0.065/0.88 on day 10; the HQ values for fluopicolide were 0.029/0.042, 0.022/0.025, and 0.010/0.019 on day 0, day 5, and day 10, for sites 1/2, respectively. From this data, we concluded that the fruits could be consumed safely.

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Flexible biodegradable citrate-based polymeric step-index optical fiber

Publication date: October 2017
Source:Biomaterials, Volume 143
Author(s): Dingying Shan, Chenji Zhang, Surge Kalaba, Nikhil Mehta, Gloria B. Kim, Zhiwen Liu, Jian Yang
Implanting fiber optical waveguides into tissue or organs for light delivery and collection is among the most effective ways to overcome the issue of tissue turbidity, a long-standing obstacle for biomedical optical technologies. Here, we report a citrate-based material platform with engineerable opto-mechano-biological properties and demonstrate a new type of biodegradable, biocompatible, and low-loss step-index optical fiber for organ-scale light delivery and collection. By leveraging the rich designability and processibility of citrate-based biodegradable polymers, two exemplary biodegradable elastomers with a fine refractive index difference and yet matched mechanical properties and biodegradation profiles were developed. Furthermore, we developed a two-step fabrication method to fabricate flexible and low-loss (0.4 db/cm) optical fibers, and performed systematic characterizations to study optical, spectroscopic, mechanical, and biodegradable properties. In addition, we demonstrated the proof of concept of image transmission through the citrate-based polymeric optical fibers and conducted in vivo deep tissue light delivery and fluorescence sensing in a Sprague-Dawley (SD) rat, laying the groundwork for realizing future implantable devices for long-term implantation where deep-tissue light delivery, sensing and imaging are desired, such as cell, tissue, and scaffold imaging in regenerative medicine and in vivo optogenetic stimulation.

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PNIPAAm-co-Jeffamine® (PNJ) scaffolds as in vitro models for niche enrichment of glioblastoma stem-like cells

Publication date: October 2017
Source:Biomaterials, Volume 143
Author(s): John M. Heffernan, James B. McNamara, Sabine Borwege, Brent L. Vernon, Nader Sanai, Shwetal Mehta, Rachael W. Sirianni
Glioblastoma (GBM) is the most common adult primary brain tumor, and the 5-year survival rate is less than 5%. GBM malignancy is driven in part by a population of GBM stem-like cells (GSCs) that exhibit indefinite self-renewal capacity, multipotent differentiation, expression of neural stem cell markers, and resistance to conventional treatments. GSCs are enriched in specialized niche microenvironments that regulate stem phenotypes and support GSC radioresistance. Therefore, identifying GSC-niche interactions that regulate stem phenotypes may present a unique target for disrupting the maintenance and persistence of this treatment resistant population. In this work, we engineered 3D scaffolds from temperature responsive poly(N-isopropylacrylamide-co-Jeffamine M-1000^® acrylamide), or PNJ copolymers, as a platform for enriching stem-specific phenotypes in two molecularly distinct human patient-derived GSC cell lines. Notably, we observed that, compared to conventional neurosphere cultures, PNJ cultured GSCs maintained multipotency and exhibited enhanced self-renewal capacity. Concurrent increases in expression of proteins known to regulate self-renewal, invasion, and stem maintenance in GSCs (NESTIN, EGFR, CD44) suggest that PNJ scaffolds effectively enrich the GSC population. We further observed that PNJ cultured GSCs exhibited increased resistance to radiation treatment compared to GSCs cultured in standard neurosphere conditions. GSC radioresistance is supported in vivo by niche microenvironments, and this remains a significant barrier to effectively treating these highly tumorigenic cells. Taken in sum, these data indicate that the microenvironment created by synthetic PNJ scaffolds models niche enrichment of GSCs in patient-derived GBM cell lines, and presents tissue engineering opportunities for studying clinically important behaviors such as radioresistance in vitro.

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Astrocytes and endoplasmic reticulum stress: A bridge between obesity and neurodegenerative diseases

Publication date: Available online 10 August 2017
Source:Progress in Neurobiology
Author(s): Cynthia A. Martin-Jiménez, Ángela García-Vega, Ricardo Cabezas, Gjumrakch Aliev, Valentina Echeverria, Janneth González, George E. Barreto
Endoplasmic reticulum (ER) is a subcellular organelle involved in protein folding and processing. ER stress constitutes a cellular process characterized by accumulation of misfolded proteins, impaired lipid metabolism and induction of inflammatory responses. ER stress has been suggested to be involved in several human pathologies, including neurodegenerative diseases and obesity. Different studies have shown that both neurodegenerative diseases and obesity trigger similar cellular responses to ER stress. Moreover, both diseases are assessed in astrocytes as evidences suggest these cells as key regulators of brain homeostasis. However, the exact contributions to the effects of ER stress in astrocytes in the various neurodegenerative diseases and its relation with obesity are not well known. Here, we discuss recent advances in the understanding of molecular mechanisms that regulate ER stress-related disorders in astrocytes such as obesity and neurodegeneration. Moreover, we outline the correlation between the activated proteins of the unfolded protein response (UPR) in these pathological conditions in order to identify possible therapeutic targets for ER stress in astrocytes. We show that ER stress in astrocytes shares UPR activation pathways during both obesity and neurodegenerative diseases, demonstrating that UPR related proteins like ER chaperone GRP 78/Bip, PERK pathway and other exogenous molecules ameliorate UPR response and promote neuroprotection.

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The value of intraoperative EABRs in auditory brainstem implantation

To compare the intraoperative electrically evoked auditory brainstem response (EABR) morphologies between neurofibromatosis II (NF2) adult auditory brainstem implant (ABI) recipients who had auditory percepts post-operatively and those who did not and between NF2 adult ABI recipients and non-NF2 pediatric ABI recipients.

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Valproic Acid Sensitizes Breast Cancer Cells to Hydroxyurea through Inhibiting RPA2 Hyperphosphorylation-Mediated DNA Repair Pathway

Publication date: Available online 9 August 2017
Source:DNA Repair
Author(s): Youjia Tian, Guochao Liu, Hui Wang, Zhujun Tian, Zuchao Cai, Fengmei Zhang, Yue Luo, Shue Wang, Gongshe Guo, Xiaowei Wang, Simon Powell, Zhihui Feng
It was reported that valproic acid (VPA, a histone deacetylase inhibitor) can sensitize cancer cells to hydroxyurea (HU, a ribonucleotide reductase inhibitor) for chemotherapy, although the mechanism of VPA-induced HU sensitization is unclear. In this study, we systematically characterized VPA-induced HU sensitization of breast cancer cells. Multiple breast cancer cell models were employed to investigate whether the safe concentration of 0.5mM VPA and 2mM HU can result in DNA double-strand breaks (DSBs) and impact cell survival. Furthermore, the underlying mechanism was explored through cell biology assays, including clonogenic survival, homologous recombination (HR) activity, immunoblot and immunofluorescence. We found that VPA and HU cooperatively suppressed cancer cell survival. VPA resulted in the accumulation of more DNA double-strand breaks (DSBs) in response to HU-induced replication arrest and was able to block HU-stimulated homologous recombination (HR) through inhibiting the activity of two key HR repair proteins by hyperphosphorylation of replication protein A2 (RPA2-p) and recombinase Rad51. However, apoptosis was not detected under this condition. In addition, the results from the survival fraction in the cells expressing defective RPA2-p showed that VPA disrupted the HU-induced RPA2-p-Rad51-mediated HR pathway. Importantly, these findings were further supported by analyzing primary-culture cells from the tissue of chemical carcinogen (DMBA)-induced breast cancer in rats. Thus, our data demonstrated that VPA and HU synergistically suppressed tumor cells via disturbing RPA2-p-mediated DNA repair pathway, which provides a new way for combining chemotherapeutic drugs to sensitize breast cancer cells.

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Reflections on a Decade

Publication date: 9 August 2017
Source:Cell Host & Microbe, Volume 22, Issue 2

We invited ten Cell Host & Microbe authors, who are experts in their field, to join us in celebrating our anniversary by highlighting an area of host-microbe research that the journal has contributed to advancing.

Teaser

We invited ten Cell Host & Microbe authors, who are experts in their field, to join us in celebrating our anniversary by highlighting an area of host-microbe research that the journal has contributed to advancing.

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Establishing Causality: Opportunities of Synthetic Communities for Plant Microbiome Research

Publication date: 9 August 2017
Source:Cell Host & Microbe, Volume 22, Issue 2
Author(s): Julia A. Vorholt, Christine Vogel, Charlotte I. Carlström, Daniel B. Müller
Plant microbiome research highlights the importance of indigenous microbial communities for host phenotypes such as growth and health. It aims to discover the molecular basis by which host-microbe and microbe-microbe interactions shape and maintain microbial communities and to understand the role of individual microorganisms, as well as their collective ecosystem function. Here, we discuss reductionist approaches to disentangle the inherent complexity of interactions in situ. Experimentally tractable, synthetic communities enable testing of hypotheses by targeted manipulation in gnotobiotic systems. Modifications of microbial, host, and environmental parameters allow for the quantitative assessment of host and microbe characteristics with dynamic and spatial resolution. We summarize first insights from this emerging field and discuss current challenges and limitations. Using multifaceted approaches to detect interactions and functions will provide new insights into the fundamental biology of plant-microbe interactions and help to harness the power of the microbiome.

Teaser

Plant microbiome research highlights the importance of indigenous microbial communities for host phenotypes such as growth and health. It aims to discover the molecular basis by which host-microbe and microbe-microbe interactions shape and maintain microbial communities and to understand the role of individual microorganisms, as well as their collective ecosystem function. Here, we discuss reductionist approaches to disentangle the inherent complexity of interactions in situ. Experimentally tractable, synthetic communities enable testing of hypotheses by targeted manipulation in gnotobiotic systems. Modifications of microbial, host, and environmental parameters allow for the quantitative assessment of host and microbe characteristics with dynamic and spatial resolution. We summarize first insights from this emerging field and discuss current challenges and limitations. Using multifaceted approaches to detect interactions and functions will provide new insights into the fundamental biology of plant-microbe interactions and help to harness the power of the microbiome.

http://ift.tt/2uqZ9AE

Innate Immunity to Intracellular Pathogens: Balancing Microbial Elimination and Inflammation

Publication date: 9 August 2017
Source:Cell Host & Microbe, Volume 22, Issue 2
Author(s): Gabriel Mitchell, Ralph R. Isberg
Recent excitement regarding immune clearance of intracellular microorganisms has focused on two systems that maintain cellular homeostasis. One system includes cellular autophagy components that mediate degradation of pathogens in membrane-bound compartments, in a process termed xenophagy. The second system is driven by interferon-regulated GTPases that promote rupture of pathogen-containing vacuoles and microbial degradation. In the case of xenophagy, pathogen sequestration and compartmentalization suppress inflammation. In contrast, interferon-driven events can lead to exposure of pathogen-associated molecular patterns to the host cytosol with consequent inflammasome activation. Paradoxically, signals and factors involved in xenophagy also mobilize interferon-regulated GTPases, which drive the inflammatory response, indicating considerable cross-talk between these pathways. How these responses are prioritized remains to be understood. In this review, we describe mechanisms of intracellular pathogen clearance that rely on the autophagy machinery and interferon-regulated GTPases, and speculate how these pathways engage each other to balance pathogen elimination with inflammation.

Teaser

In their review, Mitchell and Isberg describe mechanisms of intracellular pathogen clearance that rely on the autophagy machinery and interferon-regulated GTPases and discuss how these pathways may be interacting with each other to balance pathogen elimination with inflammation.

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Ten Strategies of Interferon Evasion by Viruses

Publication date: 9 August 2017
Source:Cell Host & Microbe, Volume 22, Issue 2
Author(s): Adolfo García-Sastre
Viruses infecting vertebrate hosts must overcome the interferon (IFN)-mediated antiviral response to replicate and propagate to new hosts. The complex regulation of the IFN response allows viruses to antagonize IFN at multiple levels. However, no single strategy appears to be the golden ticket, and viruses have adopted multiple means to dampen this host defense. This Review does not exhaustively cover all mechanisms of viral IFN antagonism. Rather it examines the ten most common strategies that viruses use to subvert the IFN response with examples from publications appearing in the last 10 years of Cell Host & Microbe. The virus-host interactions involved in induction and evasion of IFN represent a fertile area of research due to the significant large number of host and viral products that regulate this response, resulting in an intricate dance between hosts and their pathogens to achieve an optimal balance between virus replication, host disease, and survival.

Teaser

Viruses are formidable pathogens that take advantage of the infected cell machinery while disarming the antiviral host defenses. García-Sastre reviews the most common mechanisms used by viruses to antagonize the antiviral interferon response, illustrating the complexity of pathways that sense viral infection and regulate antiviral innate immune responses.

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Principles of Broad and Potent Antiviral Human Antibodies: Insights for Vaccine Design

Publication date: 9 August 2017
Source:Cell Host & Microbe, Volume 22, Issue 2
Author(s): James E. Crowe
Antibodies are the principal immune effectors that mediate protection against reinfection following viral infection or vaccination. Robust techniques for human mAb isolation have been developed in the last decade. The study of human mAbs isolated from subjects with prior immunity has become a mainstay for rational structure-based, next-generation vaccine development. The plethora of detailed molecular and genetic studies coupling the structure of antigen-antibody complexes with their antiviral function has begun to reveal common principles of critical interactions on which we can build better vaccines and therapeutic antibodies. This review outlines the approaches to isolating and studying human antiviral mAbs and discusses the common principles underlying the basis for their activity. This review also examines progress toward the goal of achieving a comprehensive understanding of the chemical and physical basis for molecular recognition of viral surface proteins in order to build predictive molecular models that can be used for vaccine design.

Teaser

Antibodies are the principal immune effectors that protect against viral reinfection. The review by Crowe outlines approaches to isolating and studying human antiviral monoclonal antibodies and details the common principles underlying the basis for their antiviral activity. Use of this understanding to build predictive models for vaccine design is discussed.

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Inflammation, Antibiotics, and Diet as Environmental Stressors of the Gut Microbiome in Pediatric Crohn’s Disease

Publication date: 9 August 2017
Source:Cell Host & Microbe, Volume 22, Issue 2
Author(s): James D. Lewis, Eric Z. Chen, Robert N. Baldassano, Anthony R. Otley, Anne M. Griffiths, Dale Lee, Kyle Bittinger, Aubrey Bailey, Elliot S. Friedman, Christian Hoffmann, Lindsey Albenberg, Rohini Sinha, Charlene Compher, Erin Gilroy, Lisa Nessel, Amy Grant, Christel Chehoud, Hongzhe Li, Gary D. Wu, Frederic D. Bushman

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Diversity of Functionally Permissive Sequences in the Receptor-Binding Site of Influenza Hemagglutinin

Publication date: 9 August 2017
Source:Cell Host & Microbe, Volume 22, Issue 2
Author(s): Nicholas C. Wu, Jia Xie, Tianqing Zheng, Corwin M. Nycholat, Geramie Grande, James C. Paulson, Richard A. Lerner, Ian A. Wilson

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Interlaminar strengthening of multidirectional laminates using polymer additive manufacturing

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): M.S. Islam, P. Prabhakar
A novel approach for improving the interlaminar shear strength (ILSS) properties of multi-directional prepreg laminates using polymer additive manufacturing (PAM) technology is proposed in this paper. Fused deposition modeling (FDM) is the PAM technology used for imparting patterns onto carbon prepregs. These modified prepregs are further used for fabricating multi-directional laminates. Prior to manufacturing the laminates, interlaminar regions that are most susceptible to delamination type failure are identified using numerical simulations for selectively reinforcing these critical regions. Next, the influence of printed reinforcements on the ILSS of modified laminates is compared against pristine laminates by conducting short beam shear (SBS) tests. Significant improvement in the ILSS values of up to 28% is observed, which can be attributed to the resistance offered by the printed reinforcements that steered the delamination surfaces along undulated paths as opposed to smooth or straight paths in pristine laminates. Such behavior corroborates the resistance to delamination offered by these printed reinforcements. In summary, this is a pioneering study for exploring the feasibility of using PAM technology for imparting reinforcements at the interlaminar regions in multi-directional laminates with the intention of minimizing delamination.

Graphical abstract

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Self-organizing silver and ultrasmall iron oxide nanoparticles prepared with ginger rhizome extract: Characterization, biomedical potential and microstructure analysis of hydrocolloids

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Olena Ivashchenko, Jacek Gapiński, Barbara Peplińska, Łucja Przysiecka, Tomasz Zalewski, Grzegorz Nowaczyk, Marcin Jarek, Anna Marcinkowska-Gapińska, Stefan Jurga
Multimodal nanoparticles (NPs) that may be used for therapies and diagnostics is the most promising trend for efficient therapy. We demonstrate that nanocomposite based on self-organizing silver and ultrasmall magnetic iron oxide NPs (MAg) produced in one-step synthesis revealed unique combination of fluorescence, bactericidal, fungicidal properties and have a potential as magnetic resonance imaging (MRI) contrast agent. Using the green chemistry approach, ginger (Zingiber officinale) rhizome extract was applied as capping agent for MAg synthesis, providing also additional fluorescent properties of NPs and inducing hydrocolloids structuring. The MAg were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive microanalysis (EDS), fluorescence microscopy, cryo-SEM, dynamic light scattering (DLS) techniques, Fourier transform infrared (FTIR) and ultraviolet–visible (UV–Vis) spectroscopies. MAg dispersions in water and some biological media are very stable which is important for biomedical application. The existence of microstructure in MAg hydrocolloids was proved. The hierarchical character and high ordering of this microstructure were discovered and its level-by-level building blocks were investigated. The microstructure was found to be responsible for fluorescence emittance of MAg hydrocolloids. The properties as well as potential application of the MAg hydrocolloids is yet to be discovered.

Graphical abstract

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Fatigue behavior of a Fe-Mn-Si shape memory alloy used for prestressed strengthening

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): E. Ghafoori, E. Hosseini, C. Leinenbach, J. Michels, M. Motavalli
Cyclic deformation and fatigue behavior of an iron-based shape memory alloy (Fe-SMA) Fe-17Mn-5Si-10Cr-4Ni-1(V,C) were studied. In the first step, cyclic tensile tests were performed to characterize the material's mechanical properties in tension (elongation at break, yield, and tensile strength) as well as the recovery behavior of the alloy. Furthermore, the effect of strain rate on the cyclic loading tests was investigated. It was observed that the strain rate has a clear influence on the stress-strain behavior of the alloy. In the second step, the fatigue behavior of the alloy after pre-straining and thermal activation under strain-controlled conditions was evaluated. While the stiffness of the alloy remained almost constant during high-cycle fatigue loading, a decrease in the recovery stress was observed, which should be taken into account in design assessments. The loss in the recovery stress was assumed to be mainly a result of a transformation-induced relaxation (TIR) under cyclic loading. Furthermore, this study examines the applicability of a constant life diagram (CLD) model to determine the fatigue limit of the alloy for different stress ratios (R). The existing results of the fatigue tests showed full consistency with the proposed fatigue design criterion. A formulation based on the CLD model was proposed for a safe design of the alloy as a structural pre-stressing element under a high-cycle fatigue loading regime.

Graphical abstract

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Cold gas dynamic spray additive manufacturing today: Deposit possibilities, technological solutions and viable applications

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): R.N. Raoelison, Ch. Verdy, H. Liao
This paper reports the current potentials of cold gas dynamic spraying (CGDS). CGDS has been significantly developed to produce several functional solutions categorized as follows: deposits with a single powder nature, composites-based deposits, nanotechnological deposits and hybrid coating/substrate assemblies. CGDS process has improved in proficiency and is still gaining attention from scientists and industry. Covering a wide range of materials, both standard and advanced, this additive manufacturing process offers substantial applications for surface functionalization, structural or dimensional restoration, bulk production providing specific material properties, and art/decoration. Progress in terms of material processing capabilities and applications are ongoing. CGDS brings opportunities of better materials and innovative solutions. This review also indicates some recent challenges of cold spraying. Those represent future research directions to increase the enactment of CGDS as a proven viable innovative additive manufacturing method.

Graphical abstract

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Microstructure, mechanical and thermionic emission properties of a directionally solidified LaB6-VB2 eutectic composite

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Xinyu Yang, Pan Wang, Zhenghong Wang, Ke Hu, Hefa Cheng, Zhi Li, Jiuxing Zhang
The directionally solidified (DS) LaB6-VB2 eutectic composite is successfully prepared by the optical floating zone technique. The effect of solidification rate on the microstructure characteristic, mechanical and thermionic properties are investigated. DS LaB6-VB2 eutectic composite presents a mixed rod and lamellar microstructures as the solidification rate is increased from 8.3 to 55.6μm/s, and the formation of rod structure is ascribed to the necking of unstable lamellar. The fracture toughness in transverse section is higher than that in longitudinal section at the same rate, and the highest fracture toughness of 7.23MPa·m^1/2 in transverse section and 6.47MPa·m^1/2 in longitudinal section are obtained at V=27.8μm/s. Thermionic emission of DS LaB6-VB2 eutectic composite obeys the Longo theory, and the optimal current density of 51.92A·cm⁻² is measured at 1873K.

Graphical abstract

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Combining stereolithography and replica molding: On the way to superhydrophobic polymeric devices for photovoltaics

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Caterina Credi, Diego Pintossi, Claudia L. Bianchi, Marinella Levi, Gianmarco Griffini, Stefano Turri
A strategy combining stereolithography (SL) and soft-lithography for the straightforward fabrication of superhydrophobic bulk devices is reported. Microtextured masters are rapidly prototyped by SL and passivated with a perfluorosilane. Such surface treatment enables the faultless fabrication of negative microstructured polydimethylsiloxane molds ultimately utilized to obtain bulk polymeric micropatterned structures by replica molding. As illustrative proof of concept, this approach is employed in the field of photovoltaics to realize the first example of superhydrophobic luminescent solar concentrators (LSCs) showing superior self-cleaning properties. Following our strategy, a new dye-doped acrylate mixture is developed and optimized to ensure complete wetting of the hollow microstructures present on the mold. By judiciously tailoring the photoinitiator concentration and by implementing a tailored double-step UV-irradiation process, complete UV-photopolymerization is achieved despite the significant thickness of the target samples. The high fidelity replication of the original SL-printed features on the daughter replicas as well as their super water-repellency are successfully demonstrated. The performance of the resulting superhydrophobic LSCs is investigated at varying device dimensions and found to be comparable with state-of-the-art systems. This study demonstrates the potential of high-resolution SL-printing in combination with replication techniques as a versatile tool to reproducibly fabricate microstructured superhydrophobic polymeric bulk devices in a straightforward fashion.

Graphical abstract

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Understanding and quantification of grain growth mechanism in ZrO2‑carbon nanotube composites

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Ben Milsom, Harshit Porwal, Giuseppe Viola, Zhipeng Gao, Micheal J. Reece
The high temperature grain growth behaviour of Y2O3 partially stabilised ZrO2 and ZrO2-CNT (0.5 and 2vol%) composites was investigated in a series of isothermal experiments carried out between 1500 and 1800°C. The grain growth activation energy was found to be 417±20kJmol⁻¹ for the ZrO2, which increased with the addition of CNTs to 509±41 and 497±17 kJ mol⁻¹ for the 0.5 and 2vol% composites respectively. A sintering exponent of 2 was observed for the ZrO2, corresponding to normal grain growth, whilst the nanocomposites showed a CNT drag dominated sintering mechanism, with exponents of 2.7 and 3.2 for the 0.5 and 2vol% composites respectively. This work confirms and quantifies the direct influence of CNTs on the grain growth mechanism and activation energy of ZrO2-CNT composites.

Graphical abstract

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Experimental and numerical study on honeycomb sandwich panels under bending and in-panel compression

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Guangyong Sun, Xintao Huo, Dongdong Chen, Qing Li
Sandwich structures have been extensively employed as lightweight composite components in aerospace and shipbuilding engineering for their high capacity of stiffness, strength and energy absorption. To explore the crushing behaviors of honeycomb sandwiches, both three-point bending (TPB) and in-panel compression (IPC) tests were performed on aluminum honeycomb sandwich panels in this study. The effects of several key structural parameters on crashworthiness characteristics and collapse mechanism were first explored through the experiments here. The experimental results divulged that crashworthiness and collapse mode of sandwich structures were greatly influenced by the structural parameters under the TPB test. The crash behaviors can be also affected by both structural and adhesive parameters in the IPC test. Through validating with the experimental data, the numerical models were established to capture some deformation and failure details in the crushing processes. Taking into account the adhesive interface in the finite element (FE) model, glue debonding was simulated for the IPC loading, which is in good agreement with the experimental results at the skin panel buckling. Based on the experimental results, theoretical solutions for the TPB test were also established to predict the peak load, energy absorption and collapse mode. This study provided a new basis for the further studies on the crashworthiness optimization of sandwich structures.

Graphical abstract

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Self nitrogen-doped carbon nanotubes as anode materials for high capacity and cycling stability lithium-ion batteries

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Jiangang Li, Feng Zhang, Chundong Wang, Changzhen Shao, Baozong Li, Yi Li, Qi-Hui Wu, Yonggang Yang
The great demand for high-power lithium-ion batteries has spurred extensive research on carbonaceous electrode materials. Herein, we reported a facile way of preparing novel carbon nanotubes with high nitrogen doping. Helical and straight 3-aminophenol formaldehyde resin nanotubes were first prepared based on the self-assembly of the chiral amphiphiles, which were then used as carbon sources to fabricate self nitrogen-doped carbon nanotubes via pyrolysis process. When the resins were carbonized at 600°C, carbon nanotubes with a high nitrogen-content of 9.6wt% were obtained, which maintained the original morphology of the resins. The electrochemical tests disclosed that the carbon nanotubes exhibited excellent Li storage capacity and superior cycling stability. A high reversible specific capacity of 1056mAhg⁻¹ at 0.1Ag⁻¹ was obtained after 300cycles, which is greatly higher than that of graphite and most of polymer derived carbonaceous materials. The research data implied that the nitrogen doping content plays an important role in the electrochemical performance of the carbon nanotubes.

Graphical abstract

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Mechanical properties of explosively welded AA2519-AA1050-Ti6Al4V layered material at ambient and cryogenic conditions

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Dariusz Boroński, Maciej Kotyk, Paweł Maćkowiak, Lucjan Śnieżek
This study presents the results of the mechanical properties of explosively welded AA2519-AA1050-Ti6Al4V layered material tested at ambient temperature and in cryogenic conditions. The possibility of modeling its mechanical properties based on the base material properties was additionally verified. Fractures of base materials and layered material specimens were also analyzed in order to determine the failure mechanisms in both temperature conditions. The results confirmed that the strength of aluminum alloys and titanium alloys improved with a decrease in temperature. The same effect was achieved for the layered material.It has been proved in this study that it is possible to model the layered material yield stress and ultimate tensile strength based on the analysis of its base material properties with some percent error. A much more problematic issue is to predict the elastic properties of the layered material described, e.g., by tensile elasticity modulus. The stiffness of the layered material depends on the load level and varies after aluminum alloy plastification. An influence of the mutual interaction of the explosively welded layers on Poisson's ratio was also observed.

Graphical abstract

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In vitro wear, corrosion and biocompatibility of electron beam melted γ-TiAl

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Ashfaq Mohammad, Abdulrahman M. Al-Ahmari, Vamsi Krishna Balla, Mitun Das, Susmit Datta, Devinder Yadav, G.D. Janaki Ram
Electron beam melting (EBM), a powder bed fusion based additive manufacturing process, has been used to fabricate Ti-48Al-2Cr-2Nb γ-TiAl samples. The samples were evaluated for their potential use in biomedical applications in terms of in vitro wear, corrosion and biocompatibility in as-deposited (AD) and hot isostatically pressed (HIPed) conditions. The samples were found to exhibit a lamellar microstructure consisting of γ-TiAl and Ti3Al (α2) phases in both the conditions. However, their in vitro wear and corrosion performance in Hank's balanced salt solution (HBSS), with and without fetal bovine serum (FBS), was found to be very different. The AD samples exhibited comparable passive behavior to commercially pure titanium (CP-Ti). Their corrosion potentials and currents were better than those of CP-Ti. The γ-TiAl samples exhibited wear rates of the order of 10⁻⁴mm³/N·m in HBSS. The presence of FBS was found to increase the corrosion and the wear rate of this alloy increased by 65%. In vitro cell culture experiments, using NIH3T3 cells, demonstrated that the EBM processed γ-TiAl is non-toxic and can allow cell adhesion and proliferation as effectively as CP-Ti.

Graphical abstract

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Fabrication of multiple-layered gradient cellular metal scaffold via electron beam melting for segmental bone reconstruction

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Maria A. Surmeneva, Roman A. Surmenev, Ekaterina A. Chudinova, Andrei Koptioug, Mikhail S. Tkachev, Svetlana N. Gorodzha, Lars-Erik Rännar
The triple- and double-layered mesh Ti-based alloy scaffolds were successfully fabricated using electron beam melting (EBM). In this study Ti-based alloy cylindrical scaffolds with different 3D architectures intended for the segmental bone defect treatment were systematically compared. All lattice-like scaffolds were additively manufactured using EBM technology from Ti6Al4V to mimic the structures of human trabecular bone. Cylindrically-shaped lattice scaffolds (outer diameter of 15mm and length of 35mm) of five different types were designed and manufactured. Four types were tubular with inner hole diameter of 5mm and two lattice layers of different density. Fifth type was cylindrical with three lattice layers of different density. In all samples outer lattice layer was most dense, and inner layers- least dense. Mechanical properties of scaffolds were determined by conducting uniaxial compression testing. The strain-stress curves for all samples with gradient porosities showed considerable ductility.

Graphical abstract

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Effect of scan pattern on the microstructure and mechanical properties of Powder Bed Fusion additive manufactured 17-4 stainless steel

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Andelle Kudzal, Brandon McWilliams, Clara Hofmeister, Frank Kellogg, Jian Yu, Joshua Taggart-Scarff, Jianyu Liang
Additive manufacturing (AM) of metallic parts is generating significant interest due to the ability to produce complex parts in a short period of time with minimal finishing required. However, the effect of laser scan strategy on the properties of finished parts is not well understood. In this paper the effects of laser scan line strategy on the microstructure and mechanical properties of stainless steel produced using metal Powder Bed Fusion (PBF) AM were characterized. Microstructure and phase identification were measured using X-ray diffraction and quantitative optical microscopy which found that all samples had a dual phase austenite-ferrite composition. Shorter scan lines perpendicular to the load direction resulted in 25% retained austenite, while elongated scan lines parallel to the load direction more than doubled the amount of austenite retained. A change of direction within the scan line path resulted in increased delamination porosity along the melt pool boundary and changes in volume fraction of retained austenite. Fractography, revealed cracks that propagated along melt pool boundaries. Understanding the effect of strategy on the microstructure and mechanical properties allows the producer of AM parts to implement materials by design strategies.

Graphical abstract

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Analysis of the 3D microstructure of tape-cast open-porous materials via a combination of experiments and modeling

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): S. Haj Ibrahim, M. Neumann, F. Klingner, V. Schmidt, T. Wejrzanowski
In the present paper, fabrication, characterization and modeling techniques are combined to analyze the microstructure of tape-cast open-porous materials. This kind of material is highly permeable to gases and at the same time has a high catalytic reactivity which leads to successful applications e.g. in high-temperature fuel cells. However, the microstructure of such material is complex and not fully understood. The main goal of this paper is to provide a realistic model of tape-cast porous microstructures based on the simulation of their fabrication process. In order to accomplish this, four different samples are fabricated by firing the green tapes obtained by the tape casting process. The microstructure of each sample is analyzed by means of micro-tomographic image data. Furthermore, a method for modeling open-porous 3D microstructures is proposed, where the cast slurry is represented by a system of spheres with a given volume fraction and radius distribution. Model-based post-processing of the simulated microstructures is proposed to improve the fit of the surface area. Finally, model validation is performed by means of a detailed statistical analysis of experimentally produced and virtual microstructures.

Graphical abstract

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Modeling and coupling effect evaluation of thermal conductivity of ternary opacifier/fiber/aerogel composites for super-thermal insulation

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Jianming Yang, Huijun Wu, Gongsheng Huang, Yuying Liang, Yundan Liao
Nano-porous silica aerogel material exhibits extensive application prospects in aerospace, industry and buildings for excellent thermal insulation and energy efficiency owing to its ultra-low thermal conductivity. To further improve the high-temperature thermal insulation and mechanical property of aerogels, infrared opacifiers and reinforcing fibers are added into the aerogel matrix to form ternary opacifier/fiber/aerogel composites. In this study a theoretical model of predicting thermal conductivity of the ternary opacifier/fiber/aerogel composite is presented and validated with experimental results. Based on the model the effects of ternary opacifier/fiber/aerogel contents on the thermal conductivity are investigated by using a seven-batch ternary factorial design. A super-thermal insulation of 0.0185W·m⁻¹·K⁻¹ is achieved when the ternary opacifier/fiber/aerogel contents are 10wt%, 5wt% and 85wt% respectively. The coupling effect of the ternary opacifier/fiber/aerogel contents on the thermal conductivity of the composites is then explored to decrease the coupling thermal conductivity and improve the thermal insulating performance of the ternary aerogel composites. The results indicate that the coupling thermal conductivity can be decreased by enlarging the difference between the fiber and opacifier contents. This study could be used in the design of ternary opacifier/fiber/aerogel composites for improving their super-thermal insulation.

Graphical abstract

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Hemispherical nosed steel projectile high-speed penetration into aluminum target

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Y.K. Xiao, H. Wu, Q. Fang, W. Zhang, X.Z. Kong
Terminal ballistic performance of high-strength projectiles penetrating into metallic targets is mostly concerned by both weapon and armor designers. Most existing works are concentrated on the rigid-eroding penetration regime, and limited studies have addressed the rigid-deforming-eroding penetration regime. In this paper, nineteen shots of hemispherical nosed D6A steel projectiles penetration test on 5A06-H112 aluminum targets is conducted with a wide range of velocities (696m/s–1870m/s). The non-monotonic dependence of depth of penetration (DOP) on the impact velocity is observed, which successively corresponds to the three penetration stages, i.e., rigid projectile penetration, deforming projectile penetration without eroding and eroding projectile penetration. Then, for the non-monotonic rigid-deforming-eroding projectile penetration regime, the applicability of the existing six classical theoretical models for both rigid and eroding projectile penetrations is evaluated. Furthermore, the transition velocities (the upper limit of rigid penetration and the lower limit of eroding penetration) are discussed and an empirical judgement criterion for the occurrence of non-monotonic dependence is proposed. Finally, by conducting the dynamic compression test, quasi-static tension test under varying temperature, etc., the Johnson-Cook model parameters for the present target and projectile are calibrated and validated by numerically simulating the present test.

Graphical abstract

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Contact-induced deformation and damage of rocks used in pavement materials

Publication date: 5 November 2017
Source:Materials & Design, Volume 133
Author(s): Carlos Celma Cervera, Denis Jelagin, Manfred N. Partl, Per-Lennart Larsson
Performance of stone-based construction materials, such as asphalt and unbound aggregate mixtures is defined to a great extent by the mechanics of the stone-to-stone interactions. Accordingly, the Discrete Element Method (DEM) is gaining popularity as a modelling tool to investigate the mechanical behavior of these materials. Contact and failure laws defining particles force-displacement relationships and the propensity of particles to break are crucial inputs for the DEM simulations. The present study aims at providing an experimental contact mechanics basis for the development of physically based stone-to-stone interaction laws. The attention is focused on investigating stone's force-displacement relationship and damage characteristics at pure normal loading for two stone materials used by the road industry. Experiments are performed at spherical contact profiles for cyclic and monotonically increasing loads. The emphasis lies on the evolution of contact compliance and accumulation of contact induced damage. The effect of surface roughness on the materials response is examined through comparative experiments performed on the specimens with different roughness values. Optical and environmental scanning electron microscopy (ESEM) observations of the contact induced damage at the material surface are presented and discussed in the context of contact mechanics. The implications of the reported experimental findings on the development of mechanics based contact and failure laws for the DEM modelling of stone-based construction materials are discussed.

Graphical abstract

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Cue-Dependent Inhibition in Posttraumatic Stress Disorder and Attention-Deficit/Hyperactivity Disorder

Publication date: Available online 9 August 2017
Source:Journal of Anxiety Disorders
Author(s): Zachary W. Adams, Michael Meinzer, Howard Mandel, Joshua Voltin, Blaine Caughron, Floyd R. Sallee, Mark Hamner, Zhewu Wang
ObjectiveAttention-deficit/hyperactivity disorder (ADHD) and posttraumatic stress disorder (PTSD) are common among military veterans, but the comorbidity of these two psychiatric disorders remains largely unstudied. Evaluating response inhibition and cue-dependent learning as behavioral and neurocognitive mechanisms underlying ADHD/PTSD can inform etiological models and development of tailored interventions.MethodA cued go/no-go task evaluated response inhibition in 160 adult males. Participants were recruited from the community and a Veterans Administration medical center. Four diagnostic groups were identified: ADHD-only, PTSD-only, ADHD+PTSD, controls.ResultsGroup differences were observed across most indices of inhibitory functioning, reaction time, and reaction time variability, whereby PTSD-only and ADHD+PTSD participants demonstrated deficits relative to controls. No cue dependency effects were observed.ConclusionFinding complement prior work on neurocognitive mechanisms underlying ADHD, PTSD, and ADHD+PTSD. Lack of expected group differences for the ADHD-only group may be due to limited power. Additional work is needed to better characterize distinctions among clinical groups, as well as to test effects among women and youth.

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Variations in the labyrinthine segment of facial nerve canal revealed by high-resolution computed tomography

To study variations in the labyrinthine segment of fallopian canal and the associated middle and inner ear malformations.

http://ift.tt/2urs6Z3

Variations in the labyrinthine segment of facial nerve canal revealed by high-resolution computed tomography

To study variations in the labyrinthine segment of fallopian canal and the associated middle and inner ear malformations.

http://ift.tt/2urs6Z3

Reliability and Validity of Speech Evaluation in Adductor Spasmodic Dysphonia

The aim of this study was to evaluate speech in patients with adductor spasmodic dysphonia (ADSD) by perceptual evaluations and acoustic measures, and to examine the reliability and validity of these measures.

http://ift.tt/2uqU2As

Auditory-Perceptual Evaluation of Dysphonia: A Comparison Between Narrow and Broad Terminology Systems

In auditory-perceptual voice analysis, a multiparameter approach and a more reductionist approach may be compared with narrow and broad phonetic transcription and used interchangeably, depending on the purpose. The aim of this study was to investigate the perspectives of a translation of the terminology used in the multiparameter Danish Dysphonia Assessment (DDA) approach into the five-parameter GRBAS system.

http://ift.tt/2uItEx8

Cross-sectional and longitudinal associations between different exercise types and food cravings in free-living healthy young adults

Publication date: 1 November 2017
Source:Appetite, Volume 118
Author(s): Clemens Drenowatz, Line H. Evensen, Linda Ernstsen, John E. Blundell, Gregory A. Hand, Robin P. Shook, James R. Hébert, Stephanie Burgess, Steven N. Blair
IntroductionAn increase in energy intake due to alterations in hedonic appetite sensations may, at least in part, contribute to lower-than-expected weight loss in exercise interventions. The aim of this study was to examine cross-sectional and longitudinal associations between habitual exercise participation and food cravings in free-living young adults.MethodsA total of 417 adults (49% male, 28 ± 4 years) reported frequency and duration of walking, aerobic exercise, resistance exercise and other exercise at baseline and every 3 months over a 12-month period. Food cravings were assessed via the Control of Eating Questionnaire at baseline and 12-month follow-up.ResultsCross-sectional analyses revealed more frequent cravings for chocolate and a greater difficulty to resist food cravings in women compared to men (p < 0.01). Only with resistance exercise significant sex by exercise interaction effects were observed with favorable responses in men but not in women. Significant main effects were shown for walking and aerobic exercise with exercisers reporting more frequent food cravings for chocolate and fruits and greater difficulty to resist eating compared to non-exercisers (p < 0.05). Longitudinal analyses revealed significant interaction effects for other exercise (p < 0.05) with favorable results in men but not women. Furthermore, significant main effects were observed for aerobic exercise, resistance exercise and total exercise with an increase in exercise being associated with a reduced difficulty to resist food cravings (p < 0.05).DiscussionThe association between exercise participation and hedonic appetite sensations varies by exercise type and sex. Even though exercise was associated with more frequent and greater difficulty to food cravings in the cross-sectional analyses, which may be attributed to greater energy demands, longitudinal results indicate beneficial effects of increased exercise on appetite control, particularly in men.

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Antenatal/early postnatal hypothyroidism alters arterial tone regulation in 2-week-old rats

The mechanisms of vascular alterations resulting from early thyroid hormones deficiency are poorly understood. We tested the hypothesis that antenatal/early postnatal hypothyroidism would alter the activity of endothelial NO-pathway and Rho-kinase pathway, which are specific for developing vasculature. Dams were treated with propylthiouracil (PTU, 7 ppm) in drinking water during gestation and 2 weeks after delivery, their progeny had normal body weight but markedly reduced blood levels of thyroid hormones (ELISA). Small arteries from 2-week-old male pups were studied using wire myography, qPCR and Western blotting. Mesenteric arteries of PTU-pups, compared to controls, demonstrated smaller maximum response to α1-adrenergic agonist methoxamine and reduced mRNA contents of smooth muscle differentiation markers α-actin and SERCA2A. Inhibition of basal NO synthesis by L-NNA led to tonic contraction of mesenteric arteries and augmented their contractile responses to methoxamine; both L-NNA effects were impaired in PTU-pups. PTU-pups demonstrated lower blood level of NO metabolites compared to control group (Griess reaction). Rho-kinase inhibitor Y27632 strongly reduced mesenteric arteries responses to methoxamine in PTU-pups, that was accompanied by elevated Rho-kinase content in their arteries in comparison to control ones. Unlike mesenteric, saphenous arteries of PTU-pups, compared to controls, had no changes in α-actin and SERCA2A contents and in responses to L-NNA and Y27632. In conclusion, thyroid hormones deficiency suppresses the anticontractile effect of NO and potentiates the procontractile Rho-kinase effects in mesenteric arteries of 2-week-old pups. Such alterations disturb perinatal cardiovascular homeostasis and might lead to cardiovascular pathologies in adulthood.

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A small molecule activator of SIRT3 promotes deacetylation and activation of manganese superoxide dismutase

Publication date: November 2017
Source:Free Radical Biology and Medicine, Volume 112
Author(s): Jiaqi Lu, Hua Zhang, Xian Chen, Yong Zou, Jiasong Li, Li Wang, Minhao Wu, Jianye Zang, Yang Yu, Wei Zhuang, Qing Xia, Jiangyun Wang
The modulation of protein acetylation network is a promising strategy for life span extension and disease treatment (Sabari et al., 2016; Giblin et al., 2014) [1,2]. A variety of small molecules have been developed to target deacetylases, but extremely few of these molecules are capable of activating the mitochondrial NAD-dependent deacetylase sirtuin-3 (SIRT3) (Gertz and Steegborn, 2016; Scholz et al., 2015) [3,4]. Manganese superoxide dismutase (MnSOD) is the major superoxide scavenger in mitochondria, whose activity is regulated by SIRT3-mediated deacetylation, particularly at the Lys68 site (Chen et al., 2011) [5]. To investigate the influence of Lys68 acetylation on MnSOD activity, we produced a mutant MnSOD protein-bearing N-acetyllysine (AcK) at its Lys68 position through the genetic code expansion approach. We solved the crystal structure of this acetylated MnSOD (MnSODK68AcK), thus revealing the structural and electrostatic basis for the significant activity decrease upon Lys68 acetylation. On the basis of an assay we developed for the SIRT3-mediated deacetylation of MnSODK68AcK, we identified a novel SIRT3 activator, 7-hydroxy-3-(4′-methoxyphenyl) coumarin (C12), which binds to SIRT3 with high affinity and can promote the deacetylation and activation of MnSOD. C12 adds to the current repertoire of extremely few SIRT3 activators, which are potentially valuable for treating a wide array of diseases via modulating the cellular acetylome.

Graphical abstract

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Fructose induced neurogenic hypertension mediated by overactivation of p38 MAPK to impair insulin signaling transduction caused central insulin resistance

Publication date: November 2017
Source:Free Radical Biology and Medicine, Volume 112
Author(s): Pei-Wen Cheng, Yu-Te Lin, Wen-Yu Ho, Pei-Jung Lu, Hsin-Hung Chen, Chi-Cheng Lai, Gwo-Ching Sun, Tung-Chen Yeh, Michael Hsiao, Ching-Jiunn Tseng, Chun-Peng Liu
Type 2 diabetes are at a high risk of complications related to hypertension, and reports have indicated that insulin levels may be associated with blood pressure (BP). Fructose intake has recently been reported to promote insulin resistance and superoxide formation. The aim of this study is to investigate whether fructose intake can enhance superoxide generation and impair insulin signaling in the NTS and subsequently elevate BP in rats with fructose-induced hypertension. Treatment with fructose for 4 weeks increased the BP, serum fasting insulin, glucose, homeostatic model assessment-insulin resistance, and triglyceride levels and reduced the serum direct high-density lipoprotein level in the fructose group. The Tempol treatment recovered the fructose-induced decrease in nitric oxide production in the NTS. Immunoblotting and immunofluorescence analyses further showed that fructose increased the p38- and fructose-induced phosphorylation of insulin receptor substrate 1 (IRS1^S307) and suppressed Akt^S473 and neuronal nitric oxide synthase phosphorylation. Similarly, fructose was able to impair insulin sensitivity and increase insulin levels in the NTS. Fructose intake also increased the production of superoxide in the NTS. The results of this study suggest that fructose might induce central insulin resistance and elevate BP by enhancing superoxide production and activating p38 phosphorylation in the NTS.

Graphical abstract

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Ultrasound versus magnetic resonance imaging of the temporomandibular joint in juvenile idiopathic arthritis: a systematic review

A systematic review of published articles on ultrasound (US) and magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) in juvenile idiopathic arthritis (JIA) was performed to answer the question "What is the sensitivity and specificity of US as compared to MRI in diagnosing acute and chronic joint changes in patients with JIA?" The most recent evidence was sought in published articles via a search of the PubMed, Ovid, and Embase databases. Article appraisal was performed by two reviewers.

http://ift.tt/2wJJhWr

Clinical application of autogenous partially demineralized dentin matrix prepared immediately after extraction for alveolar bone regeneration in implant dentistry: a pilot study

The aim of this study was to examine the efficacy and safety of autogenous partially demineralized dentin matrix (APDDM) prepared onsite, for clinical application in bone regeneration procedures related to implant dentistry, including socket preservation, alveolar ridge augmentation, and maxillary sinus floor augmentation. In this study, 16 patients underwent dental implant placement using APDDM transplantation. There were no systemic or local complications (including surgical site infection) in any of the cases, and oral rehabilitation using dental implants was successful in all cases for at least 2 years after attachment of the suprastructure.

http://ift.tt/2vQMBmf

The Computerized Perceptual Motor Skills Assessment: A new visual perceptual motor skills evaluation tool for children in early elementary grades

Publication date: October 2017
Source:Research in Developmental Disabilities, Volume 69
Author(s): Tsu-Hsin Howe, Hao-Ling Chen, Candy Chieh Lee, Ying-Dar Chen, Tien-Ni Wang
Visual perceptual motor skills have been proposed as underlying courses of handwriting difficulties. However, there is no evaluation tool currently available to assess these skills comprehensively and to serve as a sensitive measure. The purpose of this study was to validate the Computerized Perceptual Motor Skills Assessment (CPMSA), a newly developed evaluation tool for children in early elementary grades. Its test-retest reliability, concurrent validity, discriminant validity, and responsiveness were examined in 43 typically developing children and 26 children with handwriting difficulty. The CPMSA demonstrated excellent reliability across all subtests with intra-class correlation coefficients (ICCs)≥0.80. Significant moderate correlations between the domains of the CPMSA and corresponding gold standards including Beery VMI, the TVPS-3, and the eye-hand coordination subtest of the DTVP-2 demonstrated good concurrent validity. In addition, the CPMSA showed evidence of discriminant validity in samples of children with and without handwriting difficulty. This article provides evidence in support of the CPMSA. The CPMSA is a reliable, valid, and promising measure of visual perceptual motor skills for children in early elementary grades. Directions for future study and improvements to the assessment are discussed.

http://ift.tt/2vosR6r

Comparison of the Efficacy of Tenofovir Versus Tenofovir plus Entecavir in the Treatment of Chronic Hepatitis B in Patients With Poor Efficacy of Entecavir: A Systematic Review and Meta-analysis

Publication date: Available online 7 August 2017
Source:Clinical Therapeutics
Author(s): Jun Chen, Shu-Shan Zhao, Xiao-xiao Liu, Ze-Bing Huang, Yan Huang
PurposeThis study aimed to compare the efficacy between tenofovir disoproxil fumarate (TDF) and TDF plus entecavir (ETV) combination therapy in patients with chronic hepatitis B (CHB) with a poor response to ETV.MethodsWe searched the China National Knowledge Infrastructure (CNKI), PubMed, EMBASE, and SCOPE libraries for articles using the keywords chronic hepatitis B virus or CHB or HBV, entecavir or ETV, and tenofovir or TDF.FindingsFive studies (from CNKI and PubMed) with a total of 408 patients met the inclusion criteria: 212 patients in the TDF group and 196 patients in the TDF plus ETV group. The rates of viral suppression between the 2 groups were comparable at weeks 24 and 48 of treatment (P = 0.546 vs P = 0.818). In addition, the subanalysis revealed that no significant differences were observed in the rates of viral suppression between the 2 groups at week 24 (subgroup 1 [partial response to ETV]: P = 0.822; subgroup 2 [resistance to ETV]: P = 0.294) and week 48 (subgroup 1: P = 0.797; subgroup 2: P = 0.545). No significant differences were found in alanine aminotransferase normalization, hepatitis B e antigen loss, hepatitis B e antigen seroconversion, virologic breakthrough, and tolerability between the 2 groups at weeks 24 and 48. Therefore, the results suggest that TDF monotherapy should be chosen for patients with CHB with a poor response to ETV for reasons of economy and convenience.ImplicationsWe conclude that TDF monotherapy is comparable to TDF-ETV combination therapy for patients with a poor response to ETV; thus, TDF monotherapy may be a better choice for these patients. However, because of the limited citations in this meta-analysis, complete and systematic evidence is needed to evaluate the differences in efficacy and tolerability between TDF and TDF-ETV. Larger and longer randomized clinical trials and further studies should be conducted to verify the results.

http://ift.tt/2uI6KGd

Levofloxacin is phytotoxic and modifies the protein profile of lupin seedlings

Abstract

The toxicity of levofloxacin to yellow lupin plants was evaluated in this study. Recommended indexes of plant (roots and shoots) growth were determined and new indexes were proposed which better characterise the phytotoxicity of levofloxacin. These were, in particular, the activity of antioxidative enzymes, the content of free radicals, as well as the root protein content and the root protein profile. The results showed that levofloxacin considerably affected EC₅₀, measured as the activity of catalase in roots, and leaves (1.05 and 0.069 mM, respectively). The activity of peroxidase in the roots and the dry weight of seedlings were the least sensitive parameters (EC₅₀ was 1.8 and 1.76 mM, respectively). Units of toxicity clearly showed that the activity of catalase is a better measure of toxicity for low concentrations of the drug, and it is a better index of plant physiological state than the morphological parameters of seedlings. Moreover, levofloxacin changed the location of free radicals and the protein profile in plants. The changes in location of reactive oxygen species in roots were an important symptom of the drug toxicity to lupin seedlings. Our results have shown that the toxicity of levofloxacin was manifested mainly by changes in the protein profile. The content of the glyceraldehyde-3-phosphate dehydrogenase, 14-3-3-like protein A, expansin-B3-like precursor, fructose-bisphosphate aldolase, lipoxygenase, nucleotide-binding subunit of vacuolar ATPase and pyruvate dehydrogenase were found to decrease. On the other hand, plant exposure to levofloxacin resulted in an increase in the content of enolase, protein LlR18A, class III chitinase, ascorbate peroxidase, aspartate aminotransferase, alcohol dehydrogenase 1, leghemoglobin reductase-like 17 and heat shock cognate protein 80-like.

http://ift.tt/2uIgT5I

The Protruding Ear: Cosmetic and Reconstruction

Seminars in Plastic Surgery 2017; 31: 152-160
DOI: 10.1055/s-0037-1604241

Ear prominence is a relatively common cosmetic deformity with no associated functional deficits, but with profound psychosocial impact, especially in young patients. Protruding ears in children have propagated surgical advances that incorporate reconstructive techniques. Here we outline a systematic framework to evaluate the protruding ear and present various reconstructive surgical options for correction. Both cosmetic and reconstructive perspectives should be entertained when addressing this anatomical deformity.
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