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https://www.readbyqxmd.com/read/28432953/new-and-practical-mathematical-model-of-membrane-fouling-in-an-aerobic-submerged-membrane-bioreactor
#1
Mst Fazana Rahman Zuthi, Wenshan Guo, Huu Hao Ngo, Duc Long Nghiem, Faisal I Hai, Siqing Xia, Jianxin Li, Jixiang Li, Yi Liu
This study aimed to develop a practical semi-empirical mathematical model of membrane fouling that accounts for cake formation on the membrane and its pore blocking as the major processes of membrane fouling. In the developed model, the concentration of mixed liquor suspended solid is used as a lumped parameter to describe the formation of cake layer including the biofilm. The new model considers the combined effect of aeration and backwash on the foulants' detachment from the membrane. New exponential coefficients are also included in the model to describe the exponential increase of transmembrane pressure that typically occurs after the initial stage of an MBR operation...
April 4, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28432922/restricted-access-magnetic-core-mesoporous-shell-microspheres-with-c8-modified-interior-pore-walls-for-the-identification-of-20-s-protopanaxadiol-metabolites-in-rat-plasma-using-uplc-q-tof-ms-ms
#2
Jin Ling, Yingjia Yu, Jianan Feng, Changjiang Xu, Jiebing Jiang, Liping Wang, Jiakun Long, Yan Li, Gengli Duan
In the present study, a novel sample preparation method based on magnetic core-mesoporous shell microspheres with C8-modified interior pore walls (C8-Fe3O4@mSiO2) was established for the identification of 20(S)-protopanaxadiol (PPD) metabolites in rat plasma by UPLC-Q-TOF-MS/MS analysis. C8-Fe3O4@mSiO2 allowed selective extraction of PPD metabolites from rat plasma by excluding macromolecules in the plasma owing to size exclusion effect. Five extraction conditions including the amount of C8-Fe3O4@mSiO2 microspheres used, extraction time, elution solvents, elution volume, and elution time were investigated and optimized...
April 3, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28432755/mitochondria-and-ageing-role-in-heart-skeletal-muscle-and-adipose-tissue
#3
REVIEW
Kerstin Boengler, Maik Kosiol, Manuel Mayr, Rainer Schulz, Susanne Rohrbach
Age is the most important risk factor for most diseases. Mitochondria play a central role in bioenergetics and metabolism. In addition, several lines of evidence indicate the impact of mitochondria in lifespan determination and ageing. The best-known hypothesis to explain ageing is the free radical theory, which proposes that cells, organs, and organisms age because they accumulate reactive oxygen species (ROS) damage over time. Mitochondria play a central role as the principle source of intracellular ROS, which are mainly formed at the level of complex I and III of the respiratory chain...
April 21, 2017: Journal of Cachexia, Sarcopenia and Muscle
https://www.readbyqxmd.com/read/28432625/synthesis-of-magnetic-cofe2o4-ordered-mesoporous-carbon-nanocomposites-and-application-in-fenton-like-oxidation-of-rhodamine-b
#4
Jing Deng, Yi-Jing Chen, Yu-An Lu, Xiao-Yan Ma, Shan-Fang Feng, Naiyun Gao, Jun Li
CoFe2O4/ordered mesoporous carbon (OMC) nanocomposites were synthesized and tested as heterogeneous peroxymonosulfate (PMS) activator for the removal of rhodamine B. Characterization confirmed that CoFe2O4 nanoparticles were tightly bonded to OMC, and the hybrid catalyst possessed high surface area, pore volume, and superparamagnetism. Oxidation experiments demonstrated that CoFe2O4/OMC nanocomposites displayed favorable catalytic activity in PMS solution and rhodamine B degradation could be well described by pseudo-first-order kinetic model...
April 21, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28432365/effects-of-porosity-on-dynamic-indentation-resistance-of-silica-nanofoam
#5
Zhao Cang, Zhong Ying, Qiao Yu
The dynamic indentation behaviors of monolithic silica nanofoams of various porosities are investigated. When the pore size is on the nm scale, as the porosity increases, despite the decrease in mass density, the resistance offered by silica nanofoam to dynamic indentation is maintained at a high level, higher than the resistance of solid silica or regular porous silica. This phenomenon is related to the fast collapse of nanocells, which produces a locally hardened region and significantly increases the volume of material involved in impact energy dissipation...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28432018/on-the-role-of-api-in-determining-porosity-pore-structure-and-bulk-modulus-of-the-skeletal-material-in-pharmaceutical-tablets-formed-with-mcc-excipient
#6
Cathy Ridgway, Prince Bawuah, Daniel Markl, J Axel Zeitler, Jarkko Ketolainen, Kai-Erik Peiponen, Patrick Gane
The physical properties and mechanical integrity of pharmaceutical tablets are of major importance when loading with active pharmaceutical ingredient(s) (API) in order to ensure ease of processing, control of dosage and stability during transportation and handling prior to patient consumption. The interaction between API and excipient, acting as functional extender and binder, however, is little understood in this context. The API indomethacin is combined in this study with microcrystalline cellulose (MCC) at increasing loading levels...
April 18, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28431688/thermal-desorption-gas-chromatographic-methodology-for-the-determination-of-residual-solvents-in-mesoporous-silica
#7
Adissu Alemayehu Asfaw, Kris Wolfs, Ann Van Schepdael, Erwin Adams
In this work, thermal desorption-gas chromatography-flame ionization detection (TD-GC-FID) was adapted to enable the determination of residual solvents (RS) in mesoporous silica (MPSi). MPSi is often utilized in various pharmaceutical formulations or drug delivery systems and the accurate determination of RS is an important part of pharmaceutical quality control. Seven commonly used solvents (methanol, ethanol, acetone, isopropanol, dichloromethane, tetrahydrofuran and hexafluoroisopropanol) were evaluated in combination with 3 types of MPSi having pore sizes of 2-3, 15 and 25nm...
April 12, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28431687/a-rapid-impregnation-method-for-loading-desired-amounts-of-extractant-on-prepacked-reversed-phase-columns-for-high-performance-liquid-chromatographic-separation-of-metal-ions
#8
Muhammad Ramzan, Dejene Kifle, Grethe Wibetoe
A time-efficient impregnation method for loading extractant onto reversed-phase columns was developed, using di-(2-ethylhexyl) phosphoric acid (HDEHP) as a model extractant. The optimal loading conditions for the impregnation process of a standard analytical scale column was achieved by dissolving an appropriate amount of HDEHP (per void volume) in n-pentane, flushing the column with two void volumes (5mL) of impregnation solution and heating the column for a short time to remove the solvent. The process takes about one hour, a significant time reduction compared to commonly used impregnation methods (17-23h)...
April 7, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28431535/ion-and-water-binding-sites-inside-an-occluded-hourglass-pore-of-a-trimeric-intracellular-cation-tric-channel
#9
Xiaomin Ou, Jianli Guo, Longfei Wang, Hanting Yang, Xiuying Liu, Jianyuan Sun, Zhenfeng Liu
BACKGROUND: Trimeric intracellular cation (TRIC) channels are crucial for Ca(2+) handling in eukaryotes and are involved in K(+) uptake in prokaryotes. Recent studies on the representative members of eukaryotic and prokaryotic TRIC channels demonstrated that they form homotrimeric units with the ion-conducting pores contained within each individual monomer. RESULTS: Here we report detailed insights into the ion- and water-binding sites inside the pore of a TRIC channel from Sulfolobus solfataricus (SsTRIC)...
April 22, 2017: BMC Biology
https://www.readbyqxmd.com/read/28431338/the-design-and-fabrication-of-beta-sensor-system-for-in-situ-diffusion-tests-in-mudstone-in-france
#10
Zhenhua Lin, Olivier Tillement, Marie-Genevieve Blanchin, Vivek Jindal, Agnès Vinsot, Romain V H Dagnelie, Virginie Blin, Yanick Lettry, Benoit Hautefeuille
Long term in situ diffusion experiments in the Callovian-Oxfordian mudstone (France) are designed in the context of nuclear waste management. β-emitters HTO and (36)Cl radiotracers are representative of neutral and anionic species in these experiments. Studies have been carried out to design an in situ beta monitoring system in order to quantify tracer migration in the rock pore water over time. The development, design and calibration of β-emitter radiation sensors were performed. An optimised geometry was calculated for the detection chamber of (36)Cl in solution (Ø×L=30×2mm(2)) via Monte-Carlo N-Particle transport simulation tools...
April 1, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28431324/achievable-separation-performance-and-analysis-time-in-current-liquid-chromatographic-practice-for-monoclonal-antibody-separations
#11
Szabolcs Fekete, Jean-Luc Veuthey, Davy Guillarme
The separation performance of a chromatographic system is often described in terms of column efficiency and peak capacity. Thanks to the new developments in column technology over the past few years, the achievable peak capacity drastically improved and the analysis time can be significantly shortened. Indeed, highly efficient wide-pore reversed-phase (RPLC) materials packed with small fully porous and superficially porous particles can be successfully used for the analytical characterization of therapeutic proteins...
April 12, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28431243/cryo-em-structure-of-the-open-human-ether-%C3%A3-go-go-related-k-channel-herg
#12
Weiwei Wang, Roderick MacKinnon
The human ether-à-go-go-related potassium channel (hERG, Kv11.1) is a voltage-dependent channel known for its role in repolarizing the cardiac action potential. hERG alteration by mutation or pharmacological inhibition produces Long QT syndrome and the lethal cardiac arrhythmia torsade de pointes. We have determined the molecular structure of hERG to 3.8 Å using cryo-electron microscopy. In this structure, the voltage sensors adopt a depolarized conformation, and the pore is open. The central cavity has an atypically small central volume surrounded by four deep hydrophobic pockets, which may explain hERG's unusual sensitivity to many drugs...
April 20, 2017: Cell
https://www.readbyqxmd.com/read/28430869/inhibition-of-the-p2x7-panx1-complex-suppresses-spreading-depolarization-and-neuroinflammation
#13
Shih-Pin Chen, Tao Qin, Jessica L Seidel, Yi Zheng, Matthias Eikermann, Michel D Ferrari, Arn M J M van den Maagdenberg, Michael A Moskowitz, Cenk Ayata, Katharina Eikermann-Haerter
Spreading depolarization is a wave of neuronal and glial depolarization. Within minutes after spreading depolarization, the neuronal hemichannel pannexin 1 (PANX1) opens and forms a pore complex with the ligand-gated cation channel P2X7, allowing the release of excitatory neurotransmitters to sustain spreading depolarization and activate neuroinflammation. Here, we explore the hypothesis that the P2X7-PANX1 pore complex is a critical determinant of spreading depolarization susceptibility with important consequences for neuroinflammation and trigeminovascular activation...
April 20, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/28430359/sulfur-containing-gaseous-signal-molecules-ion-channels-and-cardiovascular-diseases
#14
REVIEW
Wen Yu, Hongfang Jin, Chaoshu Tang, Junbao Du, Zhiren Zhang
Sulfur-containing gaseous signal molecules including hydrogen sulfide (H2 S) and sulfur dioxide (SO2 ) were previously recognized as toxic gases. However, extensive studies have revealed that they can be generated in the cardiovascular system via a sulfur-containing amino acid metabolic pathway, playing an important part in cardiovascular physiology and pathophysiology. Ion channels are pore-forming membrane proteins present in the membrane of all biological cells; functions include establishing a resting membrane potential and controlling action potentials and other electrical signals by conducting ions across the cell membrane...
April 21, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/28430192/a-monodisperse-transmembrane-%C3%AE-helical-peptide-barrel
#15
Kozhinjampara R Mahendran, Ai Niitsu, Lingbing Kong, Andrew R Thomson, Richard B Sessions, Derek N Woolfson, Hagan Bayley
The fabrication of monodisperse transmembrane barrels formed from short synthetic peptides has not been demonstrated previously. This is in part because of the complexity of the interactions between peptides and lipids within the hydrophobic environment of a membrane. Here we report the formation of a transmembrane pore through the self-assembly of 35 amino acid α-helical peptides. The design of the peptides is based on the C-terminal D4 domain of the Escherichia coli polysaccharide transporter Wza. By using single-channel current recording, we define discrete assembly intermediates and show that the pore is most probably a helix barrel that contains eight D4 peptides arranged in parallel...
May 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28429805/bio-inspired-large-scale-highly-scattering-films-for-nanoparticle-alternative-white-surfaces
#16
Julia Syurik, Radwanul Hasan Siddique, Antje Dollmann, Guillaume Gomard, Marc Schneider, Matthias Worgull, Gabriele Wiegand, Hendrik Hölscher
Inspired by the white beetle of the genus Cyphochilus, we fabricate ultra-thin, porous PMMA films by foaming with CO2 saturation. Optimising pore diameter and fraction in terms of broad-band reflectance results in very thin films with exceptional whiteness. Already films with 60 µm-thick scattering layer feature a whiteness with a reflectance of 90%. Even 9 µm thin scattering layers appear white with a reflectance above 57%. The transport mean free path in the artificial films is between 3.5 µm and 4 µm being close to the evolutionary optimised natural prototype...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28429675/cell-biology-of-hyphal-growth
#17
Gero Steinberg, Miguel A Peñalva, Meritxell Riquelme, Han A Wösten, Steven D Harris
Filamentous fungi are a large and ancient clade of microorganisms that occupy a broad range of ecological niches. The success of filamentous fungi is largely due to their elongate hypha, a chain of cells, separated from each other by septa. Hyphae grow by polarized exocytosis at the apex, which allows the fungus to overcome long distances and invade many substrates, including soils and host tissues. Hyphal tip growth is initiated by establishment of a growth site and the subsequent maintenance of the growth axis, with transport of growth supplies, including membranes and proteins, delivered by motors along the cytoskeleton to the hyphal apex...
April 2017: Microbiology Spectrum
https://www.readbyqxmd.com/read/28429230/influence-of-implants-surface-properties-on-bone-tissue-formation-in-the-ectopic-osteogenesis-test
#18
S V Nadezhdin, E V Zubareva, Yu E Burda, Yu R Kolobov, M B Ivanov, G V Khramov, A Yu Afanas'ev
We studied the influence of the characteristics of oxide porous coatings on osteogenesis and integration of new bone tissue and titanium implant surface in the ectopic osteogenesis test. Implants with coating with pore size 2-20 μ exhibit better osteogenic and osteoconductive characteristics than implants with homogenous surface and smooth relief (pore size 0.5-5.0 μ). Physical characteristics of the surface of the material along with chemical composition of the coating are essential for the formation of bone tissue and its integration with the implant...
April 21, 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28429004/binding-site-opening-by-loop-c-shift-and-chloride-ion-pore-interaction-in-the-gabaa-receptor-model
#19
M A Michałowski, S Kraszewski, J W Mozrzymas
GABAA receptors (GABAARs) are crucial in mediating inhibition in the adult mammalian brain. Although the kinetics of this receptor has been extensively studied, the molecular picture of interactions occurring at various channel conformations remains elusive. While electrophysiology combined with mutagenesis sheds light on the role of specific residues, ultrastructural studies reveal static structures which, in the case of GABAARs, are limited to the β3 homomer. To take advantage of the newest crystal structures of cys-loop receptors, a homology model of α1β2γ2 GABAAR in the unbound closed state was built using a template of the homomeric glycine receptor in the closed state...
April 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28428949/p2x1-p2x4-and-p2x7-receptor-knock-out-mice-expose-differential-outcome-of-sepsis-induced-by-%C3%AE-haemolysin-producing-escherichia-coli
#20
Anne-Sofie Greve, Marianne Skals, Steen K Fagerberg, Wulf Tonnus, Svend Ellermann-Eriksen, Richard J Evans, Andreas Linkermann, Helle A Praetorius
α-haemolysin (HlyA)-producing Escherichia coli commonly inflict severe urinary tract infections, including pyelonephritis, which comprises substantial risk for sepsis. In vitro, the cytolytic effect of HlyA is mainly mediated by ATP release through the HlyA pore and subsequent P2X1/P2X7 receptor activation. This amplification of the lytic process is not unique to HlyA but is observed by many other pore-forming proteins including complement-induced haemolysis. Since free hemoglobin in the blood is known to be associated with a worse outcome in sepsis one could speculate that inhibition of P2X receptors would ameliorate the course of sepsis...
2017: Frontiers in Cellular and Infection Microbiology
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