Mechanism of hypoxia-induced damage to the mechanical property in human erythrocytes-band 3 phosphorylation and sulfhydryl oxidation of membrane proteins.

Introduction: The integrity of the erythrocyte membrane cytoskeletal network controls the morphology, specific surface area, material exchange, and state of erythrocytes in the blood circulation. The antioxidant properties of resveratrol have been reported, but studies on the effect of resveratrol on the hypoxia-induced mechanical properties of erythrocytes are rare. Methods: In this study, the effects of different concentrations of resveratrol on the protection of red blood cell mor-phology and changes in intracellular redox levels were examined to select an appropriate concentration for further study. The Young's modulus and surface roughness of the red blood cells and blood viscosity were measured via atomic force microsco-py and a blood rheometer, respectively. Flow cytometry, free hemoglobin levels, and membrane lipid peroxidation levels were used to characterize cell membrane damage in the presence and absence of resveratrol after hypoxia. The effects of oxida-tive stress on the erythrocyte membrane proteins band 3 and spectrin were further investigated by immunofluorescent label-ing and Western blotting. Results and discussion: Resveratrol changed the surface roughness and Young's modulus of the erythrocyte mem-brane, reduced the rate of eryptosis in erythrocytes after hypoxia, and stabilized the intracellular redox level. Further data showed that resveratrol protected the erythrocyte membrane proteins band 3 and spectrin. Moreover, resistance to band 3 pro-tein tyrosine phosphorylation and sulfhydryl oxidation can protect the stability of the erythrocyte membrane skeleton net-work, thereby protecting erythrocyte deformability under hypoxia. The results of the present study may provide new insights into the roles of resveratrol in the prevention of hypoxia and as an antioxidant.

The Wako-Saitô-Muñoz-Eaton Model for Predicting Protein Folding and Dynamics.

Despite the recent advances in the prediction of protein structures by deep neutral networks, the elucidation of protein-folding mechanisms remains challenging. A promising theory for describing protein folding is a coarse-grained statistical mechanical model called the Wako-Saitô-Muñoz-Eaton (WSME) model. The model can calculate the free-energy landscapes of proteins based on a three-dimensional structure with low computational complexity, thereby providing a comprehensive understanding of the folding pathways and the structure and stability of the intermediates and transition states involved in the folding reaction. In this review, we summarize previous and recent studies on protein folding and dynamics performed using the WSME model and discuss future challenges and prospects. The WSME model successfully predicted the folding mechanisms of small single-domain proteins and the effects of amino-acid substitutions on protein stability and folding in a manner that was consistent with experimental results. Furthermore, extended versions of the WSME model were applied to predict the folding mechanisms of multi-domain proteins and the conformational changes associated with protein function. Thus, the WSME model may contribute significantly to solving the protein-folding problem and is expected to be useful for predicting protein folding, stability, and dynamics in basic research and in industrial and medical applications.

Efficient Treatment of Phenol Wastewater by Catalytic Ozonation over Micron-Sized Hollow MgO Rods.

Phenol is a nocuous water pollutant that threatens human health and the ecological environment. CoOx-doped micron-sized hollow MgO rods were prepared for the treatment of phenol wastewater by catalytic ozonation. Magnesium sources, precipitants, initial precursor concentration, Co/Mg molar ratio, and catalyst calcination temperature were optimized to obtain the best catalysts. Prepared catalysts were also well characterized by various methods to analyze their structure and physical and chemical properties. In this process, CoOx/MgO with the largest large surface area (151.3 m3/g) showed the best catalytic performance (100 and 79.8% of phenol and chemical oxygen demand (COD) removal ratio, respectively). The hydrolysis of CoOx/MgO plays a positive role in the degradation of phenol. The catalytic mechanism of the degradation of O3 to free radicals over catalysts has been investigated by in situ electronic paramagnetic resonance (EPR). The catalyst can be reused at least five times without any activity decline. The prepared CoOx/MgO catalyst also showed excellent catalytic performance for removal and degradation of ciprofloxacin, norfloxacin, and salicylic acid.

Micro-graphite particles accelerate denitrification in biological treatment systems.

Accelerated denitrification is an essential problem in the biological treatment of nitrogenous wastewater. In this study, we report that denitrification is accelerated by micro-graphite particles (MGPs). The denitrification rate was increased by 83.4% or 11.1% in synthetic (with 0.16 g/L MGPs) or industrial nitrogenous wastewater (with 0.12 g/L MGP), respectively. The mechanism was revealed via a quantitative polymerase chain reaction (q-PCR), high-throughput sequencing, and scanning electron microscopy (SEM). The abundance of denitrifying bacteria Paracoccus in the sludge was increased by micro-graphite particles. The number of denitrifying bacteria with the nirS gene was increased significantly (75.6%). To the best of our knowledge, this is the first report that MGP could enhance denitrification via the sludge. MGP can denitrify in industrial applications.

The primacy of categories in the recognition of 12 emotions in speech prosody across two cultures.

Central to emotion science is the degree to which categories, such as Awe, or broader affective features, such as Valence, underlie the recognition of emotional expression. To explore the processes by which people recognize emotion from prosody, US and Indian participants were asked to judge the emotion categories or affective features communicated by 2,519 speech samples produced by 100 actors from 5 cultures. With large-scale statistical inference methods, we find that prosody can communicate at least 12 distinct kinds of emotion that are preserved across the 2 cultures. Analyses of the semantic and acoustic structure of the recognition of emotions reveal that emotion categories drive the recognition of emotions more so than affective features, including Valence. In contrast to discrete emotion theories, however, emotion categories are bridged by gradients representing blends of emotions. Our findings, visualized within an interactive map, reveal a complex, high-dimensional space of emotional states recognized cross-culturally in speech prosody.

WCl6 catalyzed cellulose degradation at 80 °C and lower in [BMIM]Cl.

Degradation of cellulose to reducing sugar is the key step for the conversion of cellulose to valuable chemicals. Cellulose was degraded by WCl6 in 1-butyl-3-methyl imidazole chloride at 80 °C and lower. 83% and 85.5% yield of total reducing sugar was gotten at 70 and 80 °C, respectively. Compared with inorganic acid, heteropoly acid, acidic ionic liquid and other metal chlorides, WCl6 has shown better catalytic performance for degradation of cellulose to reducing sugar. The effect of reaction temperature, reaction time, WCl6 amount and cellulose concentration were investigated. Degradation of cellulose by WCl6 in 1-butyl-3-methyl imidazole chloride is a zero reaction. WCl6 also showed excellent catalytic performance for the degradation of nature cellulose and lignocellulose. Catalyst can be reused at least 5 times without decrease of reducing sugar yield. The mechanism of degradation of WCl6 was also suggested.

Selective oxidation of methacrolein to methacrylic acid over H4PMo11VO40/C3N4-SBA-15.

Molybdovanadylphosphoric acid (HPMV) was supported on a carbon nitride-modified SBA-15 (CN-SBA-15) molecular sieve to enhance its catalytic performance for oxidation of methacrolein (MAL) to methacrylic acid (MAA). HPMV/CN-SBA exhibited increased catalytic activity (20%) and five times greater MAA selectivity (98.9%) compared to bulk HPMV. HPMV supported on CN-SBA-15 exhibited much better catalytic performance as compared to that on other supports, such as KIT-6, HY zeolite, TiO2, Al2O3, SiO2, CNTs, and NH3-modified CNTs. The supported HPMV was well characterized by FT-IR, XRD, SEM, N2 physical desorption, TG-DTA, NH3-TPD, CO2-TPD, XPS, and solid-state NMR. The CN minimized the interaction between the silica support and HPMV. HPMV was successfully separated from SBA-15, which was restricted by CN to increase stability and prevent interaction between the catalysts and support that would lead to decomposition of the catalysts during calcination and reaction. HPMV reacted with amino groups on the CN, which improved MAA selectivity and enhanced the thermal stability of the supported heteropoly acid (HPA) catalysts. This work identifies a new approach to preparing highly efficient and stable supported HPA catalysts for oxidation reactions.

Modeling the effects of positive and negative feedback in kidney blood flow control.

Blood flow in the mammalian kidney is tightly autoregulated. One of the important autoregulation mechanisms is the myogenic response, which is activated by perturbations in blood pressure along the afferent arteriole. Another is the tubuloglomerular feedback, which is a negative feedback that responds to variations in tubular fluid [Cl(-)] at the macula densa.(1) When initiated, both the myogenic response and the tubuloglomerular feedback adjust the afferent arteriole muscle tone. A third mechanism is the connecting tubule glomerular feedback, which is a positive feedback mechanism located at the connecting tubule, downstream of the macula densa. The connecting tubule glomerular feedback is much less well studied. The goal of this study is to investigate the interactions among these feedback mechanisms and to better understand the effects of their interactions. To that end, we have developed a mathematical model of solute transport and blood flow control in the rat kidney. The model represents the myogenic response, tubuloglomerular feedback, and connecting tubule glomerular feedback. By conducting a bifurcation analysis, we studied the stability of the system under a range of physiologically-relevant parameters. The bifurcation results were confirmed by means of a comparison with numerical simulations. Additionally, we conducted numerical simulations to test the hypothesis that the interactions between the tubuloglomerular feedback and the connecting tubule glomerular feedback may give rise to a yet-to-be-explained low-frequency oscillation that has been observed in experimental records.

Encoding whisker deflection velocity within the rodent barrel cortex using phase-delayed inhibition.

The primary sensory feature represented within the rodent barrel cortex is the velocity with which a whisker has been deflected. Whisker deflection velocity is encoded within the thalamus via population synchrony (higher deflection velocities entail greater synchrony among the corresponding thalamic population). Thalamic (TC) cells project to regular spiking (RS) cells within the barrel cortex, as well as to inhibitory cortical fast-spiking (FS) neurons, which in turn project to RS cells. Thus, TC spikes result in EPSPs followed, with a small time lag, by IPSPs within an RS cell, and hence the RS cell decodes TC population synchrony by employing a phase-delayed inhibition synchrony detection scheme. As whisker deflection velocity is increased, the probability that an RS cell spikes rises, while jitter in the timing of RS cell spikes remains constant. Furthermore, repeated whisker deflections with fixed velocity lead to system adaptation--TC →RS, TC →FS, and FS →RS synapses all weaken substantially, leading to a smaller probability of spiking of the RS cell and increased jitter in the timing of RS cell spikes. Interestingly, RS cell activity is better able to distinguish among different whisker deflection velocities after adaptation. In this work, we construct a biophysical model of a basic 'building block' of barrel cortex - the feedforward circuit consisting of TC cells, FS cells, and a single RS cell - and we examine the ability of the purely feedforward circuit to explain the experimental data on RS cell spiking probability, jitter, adaptation, and deflection velocity discrimination. Moreover, we study the contribution of the phase-delayed inhibition network structure to the ability of an RS cell to decode whisker deflection velocity encoded via TC population synchrony.

Silica nanotubes for lysozyme immobilization.

Silica nanotubes were synthesized and used as enzyme immobilization carriers. The immobilization profiles were described by the adsorption of lysozyme molecules from aqueous solution onto the hydrophilic silica surface. The driving force of the adsorption, structure changes in the immobilized lysozyme molecules, and enzymatic activities were investigated. A study of the zeta potentials of silica with and without the immobilized lysozyme showed that there was an increase in the isoelectric point with the increase in the loading amount of lysozyme. FTIR spectra indicated that protein secondary structure was maintained well in the immobilized molecules. It was observed that enzymatic activities first increased and then decreased with increasing surface coverage of silica nanotubes by lysozyme, which suggested that the overlap and aggregation of lysozyme molecules reduced enzymatic activities of the adsorbed lysozyme molecules at high surface coverage.