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https://www.readbyqxmd.com/read/28728113/catalase-based-hydrogen-peroxide-biosensor-for-mercury-determination-by-inhibition-measurements
#1
Basant Elsebai, Mariana Emilia Ghica, Mohammed Nooredeen Abbas, Christopher M A Brett
A new amperometric hydrogen peroxide enzyme inhibition biosensor for the indirect determination of toxic mercury ions, Hg(2+), based on catalase immobilized on a glassy carbon electrode surface by cross-linking with glutaraldehyde and bovine serum albumin, is reported. The parameters influencing biosensor performance were optimized, including enzyme loading, the amount of hydrogen peroxide, the applied potential and electrolyte pH. It was shown that the inhibition of catalase by Hg(2+) species is irreversible, with a linear inhibition response between 5×10(-11) and 5×10(-10)M...
July 11, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28678477/laps-and-spim-imaging-using-ito-coated-glass-as-the-substrate-material
#2
De-Wen Zhang, Fan Wu, Steffi Krause
Light-addressable potentiometric sensors (LAPS) and scanning photo-induced impedance microscopy (SPIM) use photocurrent measurements for spatiotemporal imaging of ion concentrations, electrical potentials, and impedance. In this work, ITO-coated glass was confirmed to produce photocurrents at anodic potentials with 405 nm diode laser illumination. Therefore, it was developed as a low cost and robust substrate material for LAPS and SPIM imaging compared to traditional expensive ultrathin Si substrates. ITO showed good ac photocurrent and pH response without surface modification and insulator...
July 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28665603/experimental-and-theoretical-evidences-of-p-type-conductivity-in-nickel-carbodiimide-nanoparticles-with-a-delafossite-structure-type
#3
Tengfei Jiang, Baptiste Polteau, Yoann Farré, Laurent Cario, Camille Latouche, Yann Pellegrin, Mohammed Boujtita, Fabrice Odobel, Franck Tessier, François Cheviré, Stéphane Jobic
Nickel carbodiimide (NiCN2) was synthesized using a two-step precipitation-decomposition route leading to a brown powder with gypsum-flower-like morphology and a large specific surface area (75 m(2)/g). This layered material crystallizes in the 2H structure type of delafossite (space group P63/mmc), which is built upon infinite (2)/∞[NiN2] layers connected by linear carbodiimide ([N═C═N](2-)) bridges. An X-ray diffraction Rietveld refinement and thermal analyses pointed out some nickel deficiencies in the material, and band structure calculations carried out on the defect compound predicted p-type conductivity in relation to a slight amount of N(2-)...
July 17, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28662503/the-effects-of-switching-to-vonoprazan-a-novel-potassium-competitive-acid-blocker-on-gastric-acidity-and-reflux-patterns-in-patients-with-erosive-esophagitis-refractory-to-proton-pump-inhibitors
#4
Hiroshi Yamashita, Atsushi Kanamori, Chise Kano, Hiroki Hashimura, Kei Matsumoto, Masahiro Tsujimae, Tetsuya Yoshizaki, Kenji Momose, Daisuke Obata, Takaaki Eguchi, Mikio Fujita, Akihiko Okada
BACKGROUND/AIM: The effects of vonoprazan and proton pump inhibitors (PPIs) in patients with reflux esophagitis (RE) have not yet been compared using multichannel intraluminal impedance-pH (MII-pH). METHODS: A total of 8 patients with persistent gastric mucosal injury, despite completing an 8-week standard PPI therapy, were enrolled in the study. While they were on standard PPI therapy, the baseline values of reflux parameters, holding time ratio (HTR) of gastric pH >4, and esophageal pH <4 were obtained by using 24 h MII-pH monitoring...
June 30, 2017: Digestion
https://www.readbyqxmd.com/read/28662022/impaired-esophageal-motility-and-clearance-post-lung-transplant-risk-for-chronic-allograft-failure
#5
Anupong Tangaroonsanti, Augustine S Lee, Michael D Crowell, Marcelo F Vela, Daryl R Jones, David Erasmus, Cesar Keller, Jorge Mallea, Francisco Alvarez, Cristina Almansa, Kenneth R DeVault, Lesley A Houghton
OBJECTIVES: Gastroesophageal reflux is common in patients post-lung transplantation (LTx) and thus considered a risk factor for aspiration and consequently allograft rejection and the development of chronic allograft failure. However, evidence supporting this remains unclear and often contradictory. Our aim was to examine the role played by esophageal motility on gastroesophageal reflux exposure, along with its clearance and that of boluses swallowed, and the relationship to development of obstructive chronic lung allograft dysfunction (o-CLAD)...
June 29, 2017: Clinical and Translational Gastroenterology
https://www.readbyqxmd.com/read/28659670/is-the-routine-use-of-impedance-analysis-for-the-diagnosis-of-gastro-esophageal-reflux-disease-more-expensive-than-conventional-ph-monitoring-cost-analysis-of-two-procedures
#6
Nurkan Törer, Özgür Aytaç
Conventional 24-h pH monitoring is the gold standard for the diagnosis of non-erosive, non-acidic gastro-esophageal reflux disease. Multichannel Intraluminal Impedance (MII) analysis markedly improves diagnostic accuracy of non-erosive, non-acidic gastro-esophageal reflux disease. However, MII catheters are more expensive than standard catheters. This study aimed to determine the rates of acid or non-acid reflux and by making a retrospective projection, to predict the costs of two algorithms. We retrospectively reviewed the medical data of 102 patients who presented to our hospital with suspected non-erosive GERD and underwent 24 h impedance/pH-monitoring...
June 2017: Indian Journal of Surgery
https://www.readbyqxmd.com/read/28654968/association-of-electrochemical-therapy-with-optical-mechanical-and-acoustic-impedance-properties-of-porcine-skin
#7
Wesley J Moy, Erica Su, Jason J Chen, Connie Oh, Joe C Jing, Yueqiao Qu, Youmin He, Zhongping Chen, Brian J F Wong
Importance: The classic management of burn scars and other injuries to the skin has largely relied on soft-tissue transfer to resurface damaged tissue with local tissue transfer or skin graft placement. In situ generation of electrochemical reactions using needle electrodes and an application of current may be a new approach to treat scars and skin. Objective: To examine the changes in optical, mechanical, and acoustic impedance properties in porcine skin after electrochemical therapy...
June 22, 2017: JAMA Facial Plastic Surgery
https://www.readbyqxmd.com/read/28648074/boronic-acid-functionalized-oxide-free-silicon-surfaces-for-the-electrochemical-sensing-of-dopamine
#8
Bruno Fabre, Fanny Hauquier
Boronic acid monolayers covalently bound to hydrogen-terminated Si(111) surfaces have been prepared from the UV-directed hydrosilylation reaction of 4-vinylbenzeneboronic acid. X-ray photoelectron spectroscopy (XPS) analysis of the modified surface revealed characteristic peaks from the attached organic molecule with the expected molecular composition and without the oxidation of underlying silicon. From XPS data, the surface coverage was estimated to be ca. 0.34 ± 0.04 ethylbenzene boronic acid chain per surface silicon atom (i...
July 5, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28638469/dual-ph-sensitive-charge-reversal-nanocomplex-for-tumor-targeted-drug-delivery-with-enhanced-anticancer-activity
#9
Qing Zhou, Yilin Hou, Li Zhang, Jianlin Wang, Youbei Qiao, Songyan Guo, Li Fan, Tiehong Yang, Lin Zhu, Hong Wu
Poly(β-L-malic acid) (PMLA), a natural aliphatic polyester, has been proven to be a promising carrier for anti-cancer drugs. In spite of excellent bio-compatibility, the application of PMLA as the drug carrier for cancer therapy is limited by its low cellular uptake efficiency. The strong negative charge of PMLA impedes its uptake by cancer cells because of the electrostatic repulsion. In this study, a dual pH-sensitive charge-reversal PMLA-based nanocomplex (PMLA-PEI-DOX-TAT@PEG-DMMA) was developed for effective tumor-targeted drug delivery, enhanced cellular uptake, and intracellular drug release...
2017: Theranostics
https://www.readbyqxmd.com/read/28631878/gas-swallow-during-meals-in-patients-with-excessive-belching
#10
N Caballero, J Serra
BACKGROUND: Swallowed gas is an important source of abdominal gas, and aerophagia is often believed as a putative cause of gas-related abdominal symptoms. However, altered gas-swallow during meals has not been demonstrated. Our aim was to characterize the number of gas swallows during meals in patients complaining of excessive belching and gaseousness and a control group without abdominal symptoms during a 24-h period. METHODS: A 24-h pH-impedance monitoring was performed in 10 patients with excessive belching, and 11 patients without digestive symptoms or reflux in the pH-impedance study...
June 20, 2017: Neurogastroenterology and Motility: the Official Journal of the European Gastrointestinal Motility Society
https://www.readbyqxmd.com/read/28631600/inhibition-of-carbonic-anhydrase-ix-by-ureidosulfonamide-inhibitor-u104-reduces-prostate-cancer-cell-growth-but-does-not-modulate-daunorubicin-or-cisplatin-cytotoxicity
#11
Anne Riemann, Antje Güttler, Verena Haupt, Henri Wichmann, Sarah Reime, Matthias Bache, Dirk Vordermark, Oliver Thews
Carbonic anhydrase IX has emerged as a promising target for cancer therapy. It is highly up-regulated in hypoxic regions and mediates pH regulation critical for tumor cell survival as well as extracellular acidification of the tumor microenvironment which promotes tumor aggressiveness via various mechanisms, such as augmenting metastatic potential. Therefore, the aim of this study was to analyze the complex interdependency between CA IX and the tumor microenvironment in prostate tumor cells in concern of potential therapeutic implications...
June 19, 2017: Oncology Research
https://www.readbyqxmd.com/read/28628496/proton-pump-inhibitor-and-selective-serotonin-reuptake-inhibitor-therapy-for-the-management-of-noncardiac-chest-pain
#12
Nikos Viazis, Konstantina Katopodi, George Karamanolis, Konstantinos Denaxas, Lazaros Varytimiadis, Michail Galanopoulos, Emmanouela Tsoukali, Dimitirs Kamberoglou, Angeliki Christidou, Dimitrios G Karamanolis, George Papatheodoridis, Gerasimos J Mantzaris
INTRODUCTION: Although gastroesophageal reflux disease is the main cause of noncardiac chest pain (NCCP), proton pump inhibitors (PPIs) benefit a minority of patients. Our prospective study evaluated the effect of PPI and selective serotonin reuptake inhibitors on the different subtypes of NCCP characterized by impedance-pH monitoring. METHODS: All NCCP patients underwent impedance-pH monitoring and on the basis of the results, those with abnormal distal esophageal acid exposure received PPIs twice daily (group A), those with a positive symptom index for chest pain received citalopram 20 mg and PPI once daily (group B), and those with a negative symptom index for chest pain received citalopram 20 mg once daily (group C)...
June 16, 2017: European Journal of Gastroenterology & Hepatology
https://www.readbyqxmd.com/read/28623447/new-approaches-to-gastroesophageal-reflux-disease
#13
William Kethman, Mary Hawn
BACKGROUND: Gastroesophageal reflux disease (GERD) is the most common gastrointestinal disorder of the esophagus. It is a chronic, progressive disorder that presents most typically with heartburn and regurgitation and atypically with chest pain, dysphagia, chronic cough, globus, or sore throat. The mainstay for diagnosis and characterization of the disorder is esophagoduodenoscopy (EGD), high-resolution esophageal manometry, and symptom-associated ambulatory esophageal pH impedance monitoring...
June 16, 2017: Journal of Gastrointestinal Surgery: Official Journal of the Society for Surgery of the Alimentary Tract
https://www.readbyqxmd.com/read/28621779/the-effective-determination-of-cd-ii-and-pb-ii-simultaneously-based-on-an-aluminum-silicon-carbide-reduced-graphene-oxide-nanocomposite-electrode
#14
Yale Wu, Tao Yang, Kuo-Chih Chou, Junhong Chen, Lei Su, Xinmei Hou
A platform for the simultaneous determination of Cd(ii) and Pb(ii) in aqueous solution has been applied based on an aluminum silicon carbide-reduced graphene oxide nanocomposite (Al4SiC4-RGO) modified bismuth film glassy carbon electrode (GCE) using square wave anodic stripping voltammetry (SWASV) for the first time. The Al4SiC4-RGO nanocomposite electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Compared with the Al4SiC4 modified GCE and bare GCE, the electrochemical performance of the Al4SiC4-RGO nanocomposite electrode is obviously enhanced resulting from the synergistic effects of Al4SiC4, RGO and bismuth film...
June 16, 2017: Analyst
https://www.readbyqxmd.com/read/28621385/electroanalytical-determination-of-escitalopram-oxalate-using-nickel-nanoparticles-modified-carbon-paste-sensor
#15
Kamal Attia, A Mona Mohamed, M Amany Fekry
A sensitive voltammetric method was described for the determination of escitalopram oxalate based on electrocatalytic oxidation at nickel nanoparticles modified chloranil carbon paste sensor in Britton-Robinson buffer (pH range from 2 to 10). The modified electrode was characterized by scanning electron microscopy, electrochemical impedance and cyclic voltammetry. The investigation of electrochemical behavior of escitalopram oxalate was performed using cyclic voltammetry and differential pulse voltammetry. The anodic peak current showed a linear range from 1...
June 2017: Acta Chimica Slovenica
https://www.readbyqxmd.com/read/28620597/feeding-problems-and-their-underlying-mechanisms-in-the-esophageal-atresia-tracheoesophageal-fistula-patient
#16
REVIEW
Lisa Mahoney, Rachel Rosen
Feeding difficulties such as dysphagia, coughing, choking, or vomiting during meals, slow eating, oral aversion, food refusal, and stressful mealtimes are common in children with repaired esophageal atresia (EA) and the reasons for this are often multifactorial. The aim of this review is to describe the possible underlying mechanisms contributing to feeding difficulties in patients with EA and approaches to management. Underlying mechanisms for these feeding difficulties include esophageal dysphagia, oropharyngeal dysphagia and aspiration, and aversions related to prolonged gastrostomy tube feeding...
2017: Frontiers in Pediatrics
https://www.readbyqxmd.com/read/28612466/reflux-cough-syndrome-assessment-of-temporal-association-between-reflux-episodes-and-cough-bursts
#17
T V K Herregods, A Pauwels, J Tack, A J P M Smout, A J Bredenoord
BACKGROUND: Gastro-esophageal reflux can be the cause of chronic cough. In the assessment of the temporal association between reflux and cough, previous studies have used a two-minute time window, based on studies in patients with heartburn. However, it remains unclear whether the optimal time window duration for the evaluation of reflux-induced cough is two minutes as well. Therefore, we aimed to determine whether a two-minute time window is optimal to diagnose reflux-induced cough. METHODS: In this multicenter study, 137 patients with chronic cough were evaluated using 24-h pH-impedance-pressure monitoring...
June 14, 2017: Neurogastroenterology and Motility: the Official Journal of the European Gastrointestinal Motility Society
https://www.readbyqxmd.com/read/28609741/electrocatalytic-activity-of-manganese-oxide-nanosphere-immobilized-onto-deoxyribonucleic-acid-modified-electrode-application-to-determine-environmental-pollutant-thiourea-at-natural-ph
#18
Afshin Maleki, Hiua Daraei, Nader Amini
Based on immobilizing manganese oxide nanospheres (MnOxNsph)/deoxyribonucleic (DNA) on glassy carbon electrode (MnOxNsph/DNA/GCE), a new electrochemical biosensor for the detection of thiourea (TU) was fabricated. In order to prepare DNA template, cyclic voltammetry (CV) method was used. Scanning electron microscopy (SEM) was used for characterization of MnOx/DNA. Electrochemical impedance spectroscopy was utilized to confirm the successful stepwise assembly procedure of the biosensor. The electrocatalytical behaviors of the biosensor were also investigated by cyclic voltammetry and differential pulse voltammetry (DPV)...
June 7, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28608820/a-multi-parametric-device-with-innovative-solid-electrodes-for-long-term-monitoring-of-ph-redox-potential-and-conductivity-in-a-nuclear-waste-repository
#19
Jordan Daoudi, Stephanie Betelu, Theodore Tzedakis, Johan Bertrand, Ioannis Ignatiadis
We present an innovative electrochemical probe for the monitoring of pH, redox potential and conductivity in near-field rocks of deep geological radioactive waste repositories. The probe is composed of a monocrystalline antimony electrode for pH sensing, four AgCl/Ag-based reference or Cl(-) selective electrodes, one Ag₂S/Ag-based reference or S(2-) selective electrode, as well as four platinum electrodes, a gold electrode and a glassy-carbon electrode for redox potential measurements. Galvanostatic electrochemistry impedance spectroscopy using AgCl/Ag-based and platinum electrodes measure conductivity...
June 13, 2017: Sensors
https://www.readbyqxmd.com/read/28605121/do-laryngoscopic-findings-reflect-the-characteristics-of-reflux-in-patients-with-laryngopharyngeal-reflux
#20
Y C Lee, O E Kwon, J M Park, Y G Eun
OBJECTIVE: To analyze the association between 24-hour multichannel intraluminal impedance-pH (24h MII-pH) parameters and each item of the reflux finding score (RFS) to determine whether the laryngoscopic findings of the RFS could reflect the characteristics of reflux in patients with laryngopharyngeal reflux (LPR). STUDY DESIGN: Prospective cohort study. SETTINGS: Tertiary care referral medical center. PARTICIPANTS: Patients complaining of LPR symptoms were evaluated via a 24h MII-pH...
June 12, 2017: Clinical Otolaryngology
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