Impact of tryptophan on the formation of TCNM in the process of UV/chlorine disinfection

Abstract

Low-pressure (LP) UV treatment after chlorine disinfection was associated with enhanced formation of trichloronitromethane (TCNM), a halonitromethane disinfection by-product (DBP), due to the chlorination of tryptophan. Evidence was found that the concentration of TCNM from tryptophan increased quickly to the maximum for the first instance. Moreover, the increase of TCNM under UV exceeded 10 times than under dark. Then, it was found to have an obvious decrease in the formation of TCNM, even finally hardly disappear. In order to elucidate reasons for this phenomenon, the effects of light intensity, initial tryptophan concentration, free chlorine concentration, pH, and tert-butanol (TBA) on the formation of TCNM were investigated under UV/chlorine treatment. Finally, the effects of tryptophan on the formation of TCNM and the direct photodegradation of TCNM under LP UV irradiation were studied for analyzing the possible pathways of TCNM formation from amino acid. Since amino acids are very common in water sources, further research into chemical oxidation of these species by LP UV and chlorine is recommended. It can help us to find the precursors of TCNM formation and reduce the risk of TCNM formation for drinking water and wastewater utilities.

https://ift.tt/2sDvXTj

Biosensors: Essentials, by Gennady Evtugyn (Lecture Notes in Chemistry Vol.84), 265 pages, Springer, 2014, ISBN 978-3-642-40240-1.

Publication date: 15 September 2018
Source:Biosensors and Bioelectronics, Volume 115
Author(s): Edwin W.H. Jager




https://ift.tt/2HffzgN

Editorial Board

Publication date: 15 September 2018
Source:Biosensors and Bioelectronics, Volume 115





https://ift.tt/2kMkbCx

Lamb larynx model for training in endoscopic and CO 2 laser-assisted surgeries for benign laryngotracheal obstructions

Abstract

Purpose

With adequate indication and meticulous execution, endoscopic procedures can efficiently treat a subset of adult and pediatric benign laryngotracheal stenosis and obstructions, but these procedures are precise and very demanding. The difference between a successful and a failed surgery, with potentially debilitating side effects, resides in small details. The learning curve is long and very few centers worldwide have a sufficient case load making adequate training difficult. While indications and concepts of endoscopic procedures can be learned in books and by observing trained colleagues, the dexterity and the precise realization need to be practiced, ideally not initially on patients.

Methods

We describe here the lamb model system for the initial training in such procedures. We provide a step-by-step guide for endoscopic approaches intended to treat pathologies such as laryngomalacia, bilateral vocal fold paralysis, posterior glottic stenosis, and laryngotracheal clefts.

Conclusions

The lamb model system does not pose ethical issues, and it is easy to obtain and to handle. It was used during an international training course for laryngotracheal stenosis by novice and advanced airway surgeons. It was unanimously judged as relevant and useful by the participants.

https://ift.tt/2xGkFn0

Orbital infections: a complete cycle 7-year audit and a management guideline

Abstract

Objectives

Orbital infections are regularly encountered and are managed by various healthcare disciplines. Sepsis of the orbit and adjacent tissues can be associated with considerable acute complication and long-term sequelae. Therefore, prompt recognition and management of this condition are crucial. This article presents the outcomes of a 7-year complete cycle audit project and describes the development of the new local guideline on the management of orbital infections in our tertiary centre.

Methods

(1) A retrospective 5-year audit cycle on patients with orbital infections. (2) A review of available evidence on the management of orbital infections. (3) A new local multidisciplinary guideline on the management of orbital infections. (4) A retrospective 2-year second audit cycle to assess the clinical outcomes.

Results

Various disciplines intersect in the management of orbital infections. Standardising the management of this condition proved to be achievable through the developed guideline. However, room for improvement in practice exists in areas such as the promptness in referring patients to specialist care, the multidisciplinary assessment of patients on admission, and the improvement of scanning requests of patients.

https://ift.tt/2LYE59B

Gold nanorod-assisted near-infrared stimulation of bullfrog sciatic nerve

Abstract

Infrared neural stimulation (INS) is a new and developing approach for neural repair, with the advantages of being non-contact, spatially precise, and artifact-free. However, the disadvantage of infrared light is that it is difficult to stimulate deep tissue because of its weak penetrating power. Therefore, this paper introduces an improved method using near-infrared laser to stimulate bullfrog sciatic nerves because of its strong penetrating power. Meanwhile, gold nanorods (Au NRs) are injected into the nerve to increase the absorption of light. The mechanism is the instantaneous temperature rise caused by the absorption of infrared light by Au NRs. The compound muscle action potential (CMAP) associated with the irradiated sciatic nerve is recorded by a multi-channel physiological signal instrument. The peak to peak amplitude (V_pp) of CMAP for sciatic nerves injected with Au NRs increases significantly compared to the CMAP for control nerves without Au NRs. These results demonstrate INS by labeling nerves with nanoparticle exhibiting latent capacity to increase the efficiency, spatial resolution, and the neural responsivity, and especially, can increase the penetration depth and reduce the requisite radiant exposure level.

https://ift.tt/2JcYtly

Raman spectral feature selection using ant colony optimization for breast cancer diagnosis

Abstract

Pathology as a common diagnostic test of cancer is an invasive, time-consuming, and partially subjective method. Therefore, optical techniques, especially Raman spectroscopy, have attracted the attention of cancer diagnosis researchers. However, as Raman spectra contain numerous peaks involved in molecular bounds of the sample, finding the best features related to cancerous changes can improve the accuracy of diagnosis in this method. The present research attempted to improve the power of Raman-based cancer diagnosis by finding the best Raman features using the ACO algorithm. In the present research, 49 spectra were measured from normal, benign, and cancerous breast tissue samples using a 785-nm micro-Raman system. After preprocessing for removal of noise and background fluorescence, the intensity of 12 important Raman bands of the biological samples was extracted as features of each spectrum. Then, the ACO algorithm was applied to find the optimum features for diagnosis. As the results demonstrated, by selecting five features, the classification accuracy of the normal, benign, and cancerous groups increased by 14% and reached 87.7%. ACO feature selection can improve the diagnostic accuracy of Raman-based diagnostic models. In the present study, features corresponding to ν(C–C) αhelix proline, valine (910–940), νs(C–C) skeletal lipids (1110–1130), and δ(CH2)/δ(CH3) proteins (1445–1460) were selected as the best features in cancer diagnosis.

https://ift.tt/2LXqPSv