View-Independent Working Memory Representations of Artificial Shapes in Prefrontal and Posterior Regions of the Human Brain

Abstract

Traditional views of visual working memory postulate that memorized contents are stored in dorsolateral prefrontal cortex using an adaptive and flexible code. In contrast, recent studies proposed that contents are maintained by posterior brain areas using codes akin to perceptual representations. An important question is whether this reflects a difference in the level of abstraction between posterior and prefrontal representations. Here, we investigated whether neural representations of visual working memory contents are view-independent, as indicated by rotation-invariance. Using functional magnetic resonance imaging and multivariate pattern analyses, we show that when subjects memorize complex shapes, both posterior and frontal brain regions maintain the memorized contents using a rotation-invariant code. Importantly, we found the representations in frontal cortex to be localized to the frontal eye fields rather than dorsolateral prefrontal cortices. Thus, our results give evidence for the view-independent storage of complex shapes in distributed representations across posterior and frontal brain regions.

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The Basal Ganglia Striosomes Affect the Modulation of Conflicts by Subliminal Information—Evidence from X-Linked Dystonia Parkinsonism

Abstract

Cognitive control is relevant when distracting information induces behavioral conflicts. Such conflicts can be produced consciously and by subliminally processed information. Interestingly, both sources of conflict interact suggesting that they share neural mechanisms. Here, we ask whether conjoint effects between different sources of conflict are modulated by microstructural basal ganglia dysfunction. To this end, we carried out an electroencephalography study and examined event-related potentials (ERPs) including source localization using a combined flanker-subliminal priming task in patients with X-linked dystonia Parkinsonism (XDP) and a group of healthy controls. XDP in its early stages is known to predominantly affect the basal ganglia striosomes. The results suggest that conjoint effects between subliminal and conscious sources of conflicts are modulated by the striosomes and were stronger in XDP patients. The neurophysiological data indicate that this effect is related to modulations in conflict monitoring and response selection (N2 ERP) mechanisms engaging the anterior cingulate cortex. Bottom-up perceptual gating, attentional selection, and motor response activation processes in response to the stimuli (P1, N1, and lateralized readiness potential ERPs) were unaffected. Taken together, these data indicate that striosomes modulate the processing of conscious and subliminal sources of conflict suggesting that microstructural basal ganglia properties are relevant for cognitive control.

http://ift.tt/2qcgbiB

Interface-induced growth of boronate-based metal-organic framework membrane on porous carbon substrate for aqueous phase molecular recognition

Publication date: 15 September 2017
Source:Chemical Engineering Journal, Volume 324
Author(s): Shucheng Liu, Sudhirkumar Shinde, Jianming Pan, Yue Ma, Yongsheng Yan, Guoqing Pan
For metal-organic frameworks (MOFs), introduction of special functional groups and integration on porous support will endow the MOF with specific molecular affinity and tunable membrane-like surface properties. Herein, we demonstrated a facile interface-induced Zn(II)-ligand-fragment co-assembly strategy to in situ fabricate boronate-based MOF membrane on hydrophobic porous carbon substrate for specific molecular recognition and separation. Due to the phenylboronic acid groups and hydrophobic porous carbon supporting layer, a catechol-containing medicinal natural flavone Luteolin was found to be efficiently and selectively recognized on the MOF composite in water-containing solution. As compared to the separated MOF particles and carbon substrate, the MOF composite exhibited similar adsorption kinetics but significant higher adsorption capacity in static separation. Dynamic separation also revealed that the MOF composite could achieve a desirable maximum adsorption capacity under mild separation condition, implying its applicability in industrial application. As a proof of this concept, a commercially available Luteolin with 85% purity could be easily extracted and concentrated to 99.90% purity by the MOF composite in highly aqueous solution, and the products possessed the similar antibacterial performance with standard substance. These results demonstrated that, a membrane-like functionalized MOF composite with enhanced surface hydrophobicity and improved molecular specificity has great potential for separation of industrial and even biological samples under water compatible conditions.

Graphical abstract

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Influence of laser offset on laser welding-brazing of Al/brass dissimilar alloys

Publication date: 15 September 2017
Source:Journal of Alloys and Compounds, Volume 717
Author(s): L. Zhou, Z.Y. Li, X.G. Song, C.W. Tan, Z.Z. He, Y.X. Huang, J.C. Feng
Laser welding-brazing of dissimilar metals 5052 aluminum alloy and H62 brass in butt configuration was performed with Zn-15%Al filler metal. Laser beam offset was defined as the deviation from the center of the laser beam to the butted joint face. Influence of laser offset (defined Al side (−) and brass side (+)) on microstructure and mechanical properties of welded-brazed joints were investigated. Satisfied and defect-free joints were obtained when laser beam was irradiated at Al side, while poor wetting at the bottom, interfacial cracks and lack of penetration occurred when laser offset was shifted to brass side. When the laser offset was −0.6–0 mm, the interfacial microstructure mainly consisted of serrated layer Al4.2Cu3.2Zn0.7 adjacent to the weld seam and continuous layer CuZn close to the brass substrate. When the laser offset moved towards brass side (0.3 mm), Al4Cu9 phase formed in between CuZn and Al4.2Cu3.2Zn0.7, due to more melting and dissolution of brass. Tensile test indicated that joint strength increased first and then reduced with laser offset from Al side to brass side, and the maximum tensile strength of 128 MPa was obtained at laser offset of −0.3 mm, which was 55.7% of that of Al base metal. All the joints fractured along the bottom of brass side with brittle fracture surface and fracture location extended into the weld seam at the upper of the joints.



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Comparison of ashes from fixed/fluidized bed combustion of swine sludge and olive by-products. Properties, environmental impact and potential uses

Publication date: November 2017
Source:Renewable Energy, Volume 112
Author(s): Despina Vamvuka, George Kaniadakis, Despina Pentari, George Alevizos, Zoe Papapolikarpou
Residues from agriculture and processing industries or from the livestock sector play an important role for the power generation sector. However, ash materials produced during combustion may create several technical and environmental problems. In this work, bottom and fly ashes obtained from lab-scale fixed/fluidized bed combustion of swine sludge, olive by-products and their mixtures, from the island of Crete, were characterized by mineralogical, chemical, particle size distribution and fusibility analyses, as well as by standard leaching tests. Slagging and fouling propensities were determined and their environmental impact and potential uses were assessed. The results showed that the ashes were rich in Ca, Si, Mg, P, K, Cu, Zn and Sr minerals. Slagging/fouling potential of swine manure was significant. Heavy metals showed less preference for fly ashes. Toxic metal ions were released in low quantities through the soil, below the legislative limit values. The low leachability of the elements was attributed to the higher alkalinity of the extracts, as well as the mineralogical and chemical composition of the solids involved. All ashes could be used as secondary building materials, or for road construction. Alternatively, they could be used in mixtures with other byproducts as liming agents and fertilizers on acidic soils.



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Mineral and fatty acid profile of high intensity pulsed electric fields or thermally treated fruit juice-milk beverages stored under refrigeration

Publication date: October 2017
Source:Food Control, Volume 80
Author(s): Laura Salvia-Trujillo, Mariana Morales-de la Peña, Alejandra Rojas-Graü, Jorge Welti-Chanes, Olga Martín-Belloso
The influence of High Intensity Pulsed Electric Fields (HIPEF) or Thermal Treatment (TT) on minerals and fatty acids of fruit juice-whole (FJ-WM) or skimmed milk (FJ-SM) beverages was assessed after processing and during chilled storage. Mineral profile of both beverages was characterized by Ca, Zn, Fe, Mg, Cu, and Mn; being Ca the macroelement detected at the highest concentration (3.06–3.17mg/100 mL). Neither HIPEF nor TT significantly affected mineral concentration of the beverages, except Fe, which augmented after HIPEF (300%) or TT (43%). During storage (56 days), mineral content in both bevearges remained highly stable, regardless of the treatment applied. 11 fatty acids were identified in untreated and processed FJ-WM beverages. Palmitic acid was detected at highest concentration (21.83–24.37 mg/100 g of fat). Immediately after HIPEF or TT, most fatty acids remained with no significant changes, only linoleic acid increased (20%) in HIPEF treated beverage. Fatty acid content of HIPEF treated FJ-WM beverages was kept constant along storage; only palmitic, linoleic and linolenic acids showed lower concentrations (12–20%) at day 56. Conversely, the concentration of most fatty acids in the heated beverage underwent a significant reduction (7–19%) with time, except palmitic acid, which remained constant. HIPEF can be considered as a potential alternative to conventional pasteurization to obtain stable mixed beverages with significant concentrations of health-related compounds.



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The ASA Committee for Neuroanesthesia and Anesthesia Quality Institute: Report for Demographic Patterns for Neurosurgical Anesthesia Practice in the United States.

No abstract available

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