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Age-related macular degeneration (AMD) is marked by a progressive loss of central vision and is the third leading cause of irreversible blindness worldwide. The exact mechanisms driving the progression of this macular degenerative condition remain elusive, and as of now, there are no available preventative measures for dry AMD. According to ancient records, ginseng affects the eyes by brightening them and enhancing wisdom. Modern pharmacological research shows that the active ingredients in ginseng, ginsenosides, may be used to prevent or improve eye diseases that threaten vision. Some articles have reported that ginsenoside Rg3 can treat diabetic retinopathy in mice, but no reports exist on its effects and mechanisms in AMD. Therefore, the role and mechanism of ginsenoside Rg3 in AMD warrant further study. This study aims to investigate the effects of Rg3 on AMD and its underlying molecular mechanisms. We established a mouse model of AMD to examine the impact of ginsenoside Rg3 on NaIO3-induced apoptosis in the retina and to explore the related intrinsic mechanisms. The in vivo results indicated that ginsenoside Rg3 prevents NaIO3-induced apoptosis in retinal pigment epithelial cells by inhibiting reactive oxygen species production and preventing the reduction in mitochondrial membrane potential. Additionally, we assessed the levels of protein expression within the apoptosis pathway. Ginsenoside Rg3 decreased the expression of Bax, cleaved caspase-3, and cleaved caspase-9 proteins. Additionally, it increased the expression of Bcl-2 by decreasing P-JNK levels. Moreover, our in vivo results showed that ginsenoside Rg3 enhanced retinal structure, increased the relative thickness of the retina, and decreased the extent of disorganization in both the inner and outer nuclear layers. Ginsenoside Rg3 may safeguard the retina against NaIO3-induced cell apoptosis by attenuating reactive-oxygen-species-mediated mitochondrial dysfunction, in which the JNK signaling pathway is also involved. These findings suggest that ginsenoside Rg3 has the potential to prevent or attenuate the progression of AMD and other retinal pathologies associated with NaIO3-mediated apoptosis. [ABSTRACT FROM AUTHOR]

Cell migration is a fundamental and functional cellular process, influenced by a complex microenvironment consisting of different cells and extracellular matrix. Recent research has highlighted that, besides biochemical cues from the microenvironment, physical cues can also greatly alter cellular behavior. However, due to the complexity of the microenvironment, little is known about how the physical interactions between migrating cells and surrounding microenvironment instructs cell movement. Here, we explore various examples of three-dimensional microenvironment reconstruction models in vitro and describe how the physical interplay between migrating cells and the neighboring microenvironment controls cell behavior. Understanding this mechanical cooperation will provide key insights into organ development, regeneration, and tumor metastasis. [ABSTRACT FROM AUTHOR]

We consider the stabilities and dynamical properties of solitons in one-dimensional spin-tensor-momentum-coupled Bose–Einstein condensates with periodical tunable Raman coupling by numerical simulating and variational approximating the time-dependent Gross–Pitaevskii equations. Our results show for a trapless system, the dynamically stabilized bright solitons can be formed by modulating Raman coupling with the initial state of polar soliton, and its evolution and movement show consistence with analytical prediction. The effects of oscillating frequency of Raman coupling are also investigated. In addition, the evolution of amplitudes of such solitons exhibits nontrivial mode with combination of two oscillations, which is different with the case of fixed Raman coupling. The periodically-modulating Raman coupling provides a new mechanism to stabilize the solitons in spin-tensor-momentum-coupled Bose–Einstein condensates, which would be beneficial for the potential study of soliton dynamics in experiment. [ABSTRACT FROM AUTHOR]

As most teleosts are unable to synthesize vitamin C, supplemental diets containing vitamin C diets play a crucial role in fish health. The aim of this study was to investigate the effect of dietary vitamin C on the intestinal enzyme activity and intestinal microbiota of silver pomfre (Pampus argenteus). Four experimental diets were supplemented with basic diets containing 300 mg of vitamin C/kg (group tjl3), 600 mg of vitamin C/kg (group tjl6), and 1200 mg of vitamin C/kg (group tjl12), as well as vitamin C-free supplemental basic diet (group tjl0), respectively. The four diets were fed to juvenile P. argenteus (average initial weight: 4.68 ± 0.93 g) for 6 weeks. The results showed that the activity of SOD (superoxide dismutase) and CAT (catalase) increased significantly while that of MDA (malondialdehyde) decreased significantly in group tjl3 compared to vitamin group tjl0. At the genus level, groups tjl0, tjl6, and tjl12 contained the same dominant microbial community, Stenotrophomonas, Photobacterium, and Vibrio, whereas group tjl3 was dominated by Stenotrophomonas, Delftia, and Bacteroides. Among the fish fed with a basic diet containing 300 mg of vitamin C/kg, the intestines exhibited a notable abundance of probiotic bacteria, including lactic acid bacteria (Lactobacillus) and Bacillus. The abundance of Aeromonas in groups tjl3 and tjl6 was lower than that of the vitamin C-free supplemental basic diet group, whereas Aeromonas was not detected in group tjl12. In addition, a causative agent of the disease outbreak in cultured P. argenteus, Photobacterium damselae subsp. Damselae (PDD) was the dominant microbiota community in groups tjl0, tjl6 and tjl12, whereas the abundance of PDD in group tjl3 was the lowest among the diets. Taken together, the diets supplied with vitamin C could influence the composition microbial community of P. argenteus. The low level of vitamin C (300 mg of vitamin C/kg per basic diet) supplementation could not only improve the antioxidant capacity but also resist the invasion of pathogenic bacteria. [ABSTRACT FROM AUTHOR]

In order to understand the application of thermite, firstly, the development process is reviewed. Then, guided by practical application problems, the application of thermites in micro energetic devices (such as microigniters and microthrust-ers), energetic agents (such as pyrotechnics, propellants and their additives, primary explosives, and explosive additives), material preparation (including material preparation and synthesis, material welding), and other fields (such assafety devices, microbial killing, metal thermal cutting and oil well plugging) are reviewed. The safety issues (including sensitivity and toxici-ty) in the application of thermites are discussed. The shortcomings of the application of thermites research are summarized, such as the type of thermites with excellent performance are relatively simple, the development of new application scenarios is insufficient, and the safety research of thermite is not deep enough. Finally, the future research direction and development trend of thermite application research are prospected, and the development direction should be to develop new thermite, expand new application fields, and further study the application safety of thermite. With 124 references. [ABSTRACT FROM AUTHOR]

Metallurgical slag such as solid waste generated in the steel industry carries environmental pollution risks, but it is rich in nutrients required by microalgae. Metallurgical slag used for carbon capture and biomass energy conversion has multiple benefits: (i) reduction and harmless treatment of metallurgical solid waste, (ii) assisting in carbon neutrality by efficient carbon fixation, and (iii) production of biodiesel from CO2. In this study, AOD, BOF, BFS, HVS, and VTS slag were applied to culture Chlorella pyrenoidosa (C. pyrenoidosa) with the regulation of growth, carbon fixation, and lipid synthesis. An excellent fixed amount of CO2 with 94.59 mg is obtained from C. pyrenoidosa biomass at BOF slag added (mass ratio of CO2 captured/microalgae/slag with 1.99/1.00/10.53) since high Ca/Mg mass ratio of 419 (8.38 mg/L Ca and 0.02 mg/L Mg), no Cr and low concentration of Al (0.04 mg/L) contribute to regulating antioxidant enzyme activity (SOD and POD) to resist ROS and improving PEPC activity to reduce carbon flux toward lipid to promote biomass synthesis. Both metal concentrations from Ca (5.86 mg/L), Mg (0.05 mg/L), Al (0.42 mg/L), and Cr (0.006 mg/L) and suitable pH (10.53) in AOD leaching solution at solid/liquid ratio of 0.5 g/L change carbon flow toward efficient lipid synthesis (47.07 wt%) by continuously providing raw materials and energy by regulating ACC, ME, and PEPC activities. High value‐added biodiesel with high concentrations of C16 and C18 methyl esters from lipid of C. pyrenoidosa is achieved, following other ecological and economic benefits including 197 mg CO2 captured and 2198 mg AOD applied with harmless. In this study, C. pyrenoidosa is cultured with elements from metallurgical slag solid waste, which promotes C. pyrenoidosa efficient carbon fixation to assist in carbon neutrality, and provides guidance for CO2 conversion to high‐value‐added products with low cost. [ABSTRACT FROM AUTHOR]

Carbonyl reductases are useful for producing optically active alcohols from their corresponding prochiral ketones. Herein, we applied a computer‐assisted strategy to increase the thermostability of a previously constructed carbonyl reductase, LsCRM4 (N101D/A117G/F147L/E145A), which showed an outstanding activity in the synthesis of the ticagrelor precursor (1S)‐2‐chloro‐1‐(3,4‐difluorophenyl)ethanol. The stability changes introduced by mutations at the flexible sites were predicted using the computational tools FoldX, I‐Mutant 3.0, and DeepDDG, which demonstrated that 12 virtually screened mutants could be thermally stable; 11 of these mutants exhibited increased thermostability. Then a superior mutant LsCRM4‐V99L/D150F was screened out from the library that was constructed by iteratively combining the beneficial sites, which showed a 78% increase in activity and a 17.4°C increase in melting temperature compared to LsCRM4. Our computer‐assisted design and combinatorial strategy dramatically increased the efficiency of thermostable enzyme production. [ABSTRACT FROM AUTHOR]

Nocardia seriolae is the primary aetiological agent of nocardiosis in fish, which causes mass mortality in freshwater and marine fish. β‐ketoacyl‐ACP synthase (KAS) is one of the essential enzymes in the synthesis of mycolic acids (MASs) in Mycobacterium spp. and has been chosen as the target for therapeutic intervention in mycobacterial diseases. In the present study, a kasB homologue gene (kasB) was identified in the genome of N. seriolae, and the gene‐deficient mutant (ΔkasB) was generated based on a clinical isolate, XSYC‐Ns. Compared to the wild‐type (WT) strain, the ΔkasB showed a measurably growth defect in vitro but retained the acid‐fastness in acid‐fast staining. Observation of the cell ultrastructure showed some alterations in the cell wall of the ΔkasB strain. Compared to its original strain, the cell wall lipid layer seemed sparser, and a wider electron‐transparent zone was observed in the cell wall of ΔkasB strain. Moreover, the ΔkasB strain showed impaired ability of cell invasion as well as intracellular survival in the cell line originating from the head‐kidney of the large yellow croaker (LYC‐hK), compared to its original strain. In addition, the deficiency of ΔkasB significantly attenuated the virulence of N. seriolae in largemouth bass. The present study suggested that the ΔkasB gene might be involved in the synthesis of extracellular cell‐wall lipids in N. seriolae and play a crucial role in its pathogenicity. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, we focus on the investigations on the stochastic stability and the stochastic resonance (SR) phenomena for a FitzHugh-Nagumo system with time delay induced by a multiplicative non-Gaussian colored noise and an additive Gaussian colored noise. By use of the fast descent method, the unified colored noise approximation and the two-state theory for the SR, the stationary probability density function (SPDF) and the signal-to-noise ratio (SNR) caused by different noise terms and time delay are explored. The investigation results indicate that the two noise intensities, time delay and the departure parameter from the Gaussian noise can all reduce the probability density around the two stable states and destroy the stability of the neural system; while the two noise correlation times τ and τ 0 can both improve the probability density around both stable states and reinforce the biological stability of the neural system. As regards the SNR, it is found that the two noise intensities and the departure coefficient can all weaken the SR effect, while time delay α and the correlation time τ of the multiplicative noise will always magnify the SR phenomenon. It is worth to mention that the correlation time τ 0 of the additive noise can stimulate the SR effect, but not alter the maximum of the SNR. [ABSTRACT FROM AUTHOR]

In order to explore the pre-ignition reaction of aluminum/polytetrafluoroethylene (AI/PTFE) material, AI2O3/PTFE composites were prepared by ultrasonic mixing method. The crystal structure, microstructure and thermochemical properties were characterized and the thermochemical reaction characteristics and influencing factors were analyzed. The results show that AI2O3 can delay the initial temperature of PTFE melting. The smaller the particle size of Al2O3 and PTFE, the easier it is for the Al2O3 /PTFE material to re-act and release more heat. AI2O3 with small particle size can delay the initial temperature of AIF3 formation reaction and advance the initial temperature of AIF3 crystal transformation reaction, thus increasing the concentrated heat release of the reaction. The reaction degree of AI2O3 (50nm) and PTFE (1 jum ) is the highest. The thermochemical reaction properties of a-AI2O3/PTFE are better than those of y-AI2O3/PTFE and amorphous AI2O3/PTFE. The thermochemical reaction of AI2O3/PTFE exhibits the typical kinetic charac-teristics. With the increase of the heating rate, the peak temperature of the main heat release peak of the reaction increases. The calculated apparent activation energy of AI2O3/PTFE reaction is 45.0kJ/mol. [ABSTRACT FROM AUTHOR]

Maintaining genomic stability is a prerequisite for proliferating NPCs to ensure genetic fidelity. Though histone arginine methylation has been shown to play important roles in safeguarding genomic stability, the underlying mechanism during brain development is not fully understood. Protein arginine N-methyltransferase 5 (PRMT5) is a type II protein arginine methyltransferase that plays a role in transcriptional regulation. Here, we identify PRMT5 as a key regulator of DNA repair in response to double-strand breaks (DSBs) during NPC proliferation. Prmt5F/F; Emx1-Cre (cKO-Emx1) mice show a distinctive microcephaly phenotype, with partial loss of the dorsal medial cerebral cortex and complete loss of the corpus callosum and hippocampus. This phenotype is resulted from DSBs accumulation in the medial dorsal cortex followed by cell apoptosis. Both RNA sequencing and in vitro DNA repair analyses reveal that PRMT5 is required for DNA homologous recombination (HR) repair. PRMT5 specifically catalyzes H3R2me2s in proliferating NPCs in the developing mouse brain to enhance HR-related gene expression during DNA repair. Finally, overexpression of BRCA1 significantly rescues DSBs accumulation and cell apoptosis in PRMT5-deficient NSCs. Taken together, our results show that PRMT5 maintains genomic stability by regulating histone arginine methylation in proliferating NPCs. [ABSTRACT FROM AUTHOR]

Aldo‐keto reductases (AKRs) are important biocatalysts that can be used to synthesize chiral pharmaceutical alcohols. In this study, the catalytic activity and stereoselectivity of a NADPH‐dependent AKR from Kluyveromyces dobzhanskii (KdAKR) toward t‐butyl 6‐chloro (5S)‐hydroxy‐3‐oxohexanoate ((5S)‐CHOH) were improved by mutating its residues in the loop regions around the substrate‐binding pocket. And the thermostability of KdAKR was improved by a consensus sequence method targeted on the flexible regions. The best mutant M6 (Y28A/L58I/I63L/G223P/Y296W/W297H) exhibited a 67‐fold higher catalytic efficiency compared to the wild‐type (WT) KdAKR, and improved R‐selectivity toward (5S)‐CHOH (dep value from 47.6% to >99.5%). Moreover, M6 exhibited a 6.3‐fold increase in half‐life (t1/2) at 40°C compared to WT. Under the optimal conditions, M6 completely converted 200 g/L (5S)‐CHOH to diastereomeric pure t‐butyl 6‐chloro‐(3R, 5S)‐dihydroxyhexanoate ((3R, 5S)‐CDHH) within 8.0 h, with a space‐time yield of 300.7 g/L/day. Our results deepen the understandings of the structure−function relationship of AKRs, providing a certain guidance for the modification of other AKRs. [ABSTRACT FROM AUTHOR]

Structural information can help engineer enzymes. Usually, specific amino acids in particular regions are targeted for functional reconstruction to enhance the catalytic performance, including activity, stereoselectivity, and thermostability. Appropriate selection of target sites is the key to structure‐based design, which requires elucidation of the structure–function relationships. Here, we summarize the mutations of residues in different specific regions, including active center, access tunnels, and flexible loops, on fine‐tuning the catalytic performance of enzymes, and discuss the effects of altering the local structural environment on the functions. In addition, we keep up with the recent progress of structure‐based approaches for enzyme engineering, aiming to provide some guidance on how to take advantage of the structural information. [ABSTRACT FROM AUTHOR]

In this paper, the characteristics for the state transition between the boom state and the extinction one, varius stochastic resonance (SR) phenomena for a species population system induced by double time delays and colored cross-correlated Gaussian noises are investigated. The control of the species population system has an important effect on ecological balance and the development of human living environment. By means of the numerical calculation of the mean extinction time and the stationary probability density function (SPDF), we can figure out some fact: both external and internal noises, the noise correlation strength and its correlation time, one time delay can all reduce the ecological stability and shorten the survival time of the system; while the other time delay can enhance significantly the biological stability and postpone the extinction of the population. For the mean extinction time (MET) of the species population, it is found that noise correlation strength, time delay, the noise correlation time can all reduce the peak value of the MET, which leads to the reduction of the life cycle. Inversely, the other time delay will not change the maximum of the MET, and induce the peak value to shift to the left. With respect to the SNR, it is discovered that in the noise correlation strength and its correlation time, one-time delay mainly plays a prominent role in inhibiting the SR effect. On the contrary, the multiplicative noise can result in the enhancement of the resonant peak. In particular, the other time delay and the additive noise can stimulate the SR effect for the SNR during the initial period. However, the further increase of them will bring about the reduction of the resonant phenomenon. [ABSTRACT FROM AUTHOR]

The shape of rockfalls significantly affects the performance of the impact cushion, which is manifested by the difference in the impact force and the penetration depth of the rockfall during the collision. In this study, we built the collision numerical model between rockfalls and cushions based on the results from previous studies, and simulated the collision process of rockfalls with four different shapes (cylindrical, cuboid, spherical, and cubic) and different cushions. Essential parameters when rockfalls impact cushions are calculated, including the maximum impact forces on the surface and bottom of the cushions and the maximum penetration depth of the rockfall. The results showed that the maximum impact force on the surface and the bottom of the cushions varies with the rockfall shapes. The maximum impact force on the cushion surface caused by cylindrical rockfall is the smallest, followed by the cuboid rockfall, the cube rockfall, and the spherical rockfall. The maximum impact force at the cushion bottom also follows this trend. However, the penetration depth of cuboid rockfall is the smallest, followed by the cylindrical rockfall, the cubic rockfall, and the spherical rockfall. The results of this study provide more extensive theoretical support for rockfall disaster prevention using gravel cushions. [ABSTRACT FROM AUTHOR]

The emerging outbreak of monkeypox is closely associated with the viral infection and spreading, threatening global public health. Virus‐induced cell migration facilitates viral transmission. However, the mechanism underlying this type of cell migration remains unclear. Here we investigate the motility of cells infected by vaccinia virus (VACV), a close relative of monkeypox, through combining multi‐omics analyses and high‐resolution live‐cell imaging. We find that, upon VACV infection, the epithelial cells undergo epithelial–mesenchymal transition‐like transformation, during which they lose intercellular junctions and acquire the migratory capacity to promote viral spreading. After transformation, VACV‐hijacked RhoA signaling significantly alters cellular morphology and rearranges the actin cytoskeleton involving the depolymerization of robust actin stress fibers, leading‐edge protrusion formation, and the rear‐edge recontraction, which coordinates VACV‐induced cell migration. Our study reveals how poxviruses alter the epithelial phenotype and regulate RhoA signaling to induce fast migration, providing a unique perspective to understand the pathogenesis of poxviruses. [ABSTRACT FROM AUTHOR]

Carbonyl reductase (CR)‐catalyzed bioreduction in the organic phase and the neat substrate reaction system is a lasting challenge, placing higher requirements on the performance of enzymes. Protein engineering is an effective method to enhance the properties of enzymes for industrial applications. In the present work, a single point mutation E145A on our previously constructed CR mutant LsCRM3, coevolved thermostability, and activity. Compared with LsCRM3, the catalytic efficiency kcat/KM of LsCRM3‐E145A (LsCRM4) was increased from 6.6 to 21.9 s−1 mM−1. Moreover, E145A prolonged the half‐life t1/2 at 40°C from 4.1 to 117 h, Tm ${T}_{m}$ was increased by 5°C, T5030 ${T}_{50}^{30}$ was increased by 14.6°C, and Topt was increased by 15°C. Only 1 g/L of lyophilized Escherichia coli cells expressing LsCRM4 completely reduced up to 600 g/L 2‐chloro‐1‐(3,4‐difluorophenyl)ethanone (CFPO) within 13 h at 45°C, yielding the corresponding (1S)‐2‐chloro‐1‐(3,4‐difluorophenyl)ethanol ((S)‐CFPL) in 99.5% eeP, with a space‐time yield of 1.0 kg/L d, the substrate to catalyst ratios (S/C) of 600 g/g. Compared with LsCRM3, the substrate loading was increased by 50%, with the S/C increased by 14 times. Compared with LsCRWT, the substrate loading was increased by 6.5 times. In contrast, LsCRM4 completely converted 600 g/L CFPO within 12 h in the neat substrate bioreaction system. [ABSTRACT FROM AUTHOR]

The current study was performed to examine the acute toxicity of mercuric chloride (HgCl2) on the silver carp (Hypophthalmichthys molitrix) larvae. Probit analysis was used to determine the median lethal concentration (LC50). The LC50 values of Hg2+ for the fish larvae at 24, 48, 72, and 96 h were 267.72, 252.97, 225.57, and 97.80 μg/L, respectively. The safe concentration of Hg was 9.78 μg/L for fish larvae. Based on the 96 h LC50, fish were exposed to four different groups including 0, 6.11, 12.23, and 24.45 μg/L for 96 h to assess the effects of different concentrations of Hg2+ on antioxidant capacity, energy metabolism parameters, and related gene expression. The findings revealed that there were no significant differences in the activities of superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) in fish larvae among all the groups (P < 0.05). In the 12.23 μg/L group, fish larvae had a maximum in catalase (CAT) activity. The creatine kinase (CK) activities of fish larvae in control and 6.11 μg/L groups were significantly lower than those groups (P < 0.05). A high concentration of Hg2+ significantly upregulated the mRNA levels of heat shock protein 70 (HSP70) and metallothionein (MT) genes in fish larvae. Furthermore, the IBR index value showed the highest value in the 24.45 μg/L group. Overall, this study provides an increased understanding of the effects of Hg-acute toxicity on silver carp larvae. [ABSTRACT FROM AUTHOR]

Copyright of Crustaceana is the property of Brill Academic Publishers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Glycoside hydrolases (GHs) exhibit high activity and stability under harsh conditions, such as high temperatures and extreme pHs, given their wide use in industrial biotechnology. However, strategies for improving the acidophilic and alkalophilic adaptations of GHs are poorly summarized due to the complexity of the mechanisms of these adaptations. This review not only highlights the adaptation mechanisms of acidophilic and alkalophilic GHs under extreme pH conditions, but also summarizes the recent advances in engineering the pH performances of GHs with a focus on four strategies of protein engineering, enzyme immobilization, chemical modification, and medium engineering (additives). The examples described here summarize the methods used in modulating the pH performances of GHs and indicate that methods integrated in different protein engineering techniques or methods are efficient to generate industrial biocatalysts with the desired pH performance and other adapted enzyme properties. [ABSTRACT FROM AUTHOR]

This article proposes a novel MPPT algorithm based on the firefly algorithm and elite ant system-trained Elman neural network (FA-EAS-ElmanNN). First, the position of fireflies is randomly initialized by the firefly algorithm (FA), meanwhile the firefly individuals with higher attractiveness degree value are selected as the optimal solution. Second, the extra pheromones are artificially released to boost the positive feedback effect and convergence rate of the elite ant system (EAS). Third, the weight and threshold of the Elman neural network (ElmanNN) are updated by the FA and EAS. Also, the trained ElamnNN is employed to acquire the maximum voltage of the photovoltaic (PV) array. At last, the PID controller and PWM technology are adapted to regulate the switch time of the boost converter. Furthermore, MATLAB/Simulink is adopted to acquire the datasets of irradiance, temperature, and maximum voltage and validate the reliability and superiority of the proposed algorithm under complex atmospheric conditions. The tracking characteristic, response speed, and efficiency of the proposed MPPT algorithm are contrasted with the particle swarm optimization (PSO), ant colony optimization (ACO), ACO-artificial neural network (ACO-ANN), and PSO-RBF neural network (PSO-RBNFNN) algorithm via simulation. The efficiency of the FA-EAS-ElmanNN algorithm is 99.73%, compared with the ACO-ANN, PSO-RBFNN, PSO, and ACO algorithm, which is increased by 0.49%, 0.58%, 1.2% %, and 1.5%, respectively. Additionally, the experimental setup is built to demonstrate the tracking characteristic of the proposed MPPT algorithm. [ABSTRACT FROM AUTHOR]

Due to the poor tracking performance and significant chattering of traditional sliding mode control in the maximum power point tracking (MPPT) algorithm, a novel MPPT algorithm based on sliding mode control for photovoltaic systems is proposed in this paper. The sliding mode control structure and new sliding mode surface of the multi-power reaching law are designed with the boost converter as the carrier of the photovoltaic system, and the sigmoid function is proposed to replace the symbolic function and saturation function in the power reaching law to improve the reaching rate and control quality of the traditional sliding mode control. Furthermore, the Liapunov function is employed to analyze the accessibility, existence and stability of the improved sliding mode control. Simulation results under dynamic and partial shading conditions show that compared with exponential sliding mode and constant speed sliding mode, the improved sliding mode control strategy can quickly track the maximum power point of photovoltaic systems under various atmospheric conditions. The proposed MPPT algorithm has stronger robustness and universality. Additionally, the efficiency of the proposed algorithm is improved by 2.3% and 5.6% as compared to the exponential sliding model control algorithm and constant velocity sliding model control algorithm. In addition, the experimental platform is constructed to further validate the feasibility and effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

The internal flow characteristics and performance prediction of the axial flow pumping system is simulated by using N-S equation combined with k-ε standard turbulence model through the commercial Computation Fluid Dynamic (CFD) applications. The experimental test data of pumping system is obtained from the flow range of 22~40 kg/s, and 7 flow values are selected. The results show that a good agreement is achieved between the small flow condition and the design flow conditions. The large flow condition is complicated under the enclosed suction sump, in which a considerable difference with experimental data exists. Meanwhile, the results indicate that the obvious wall vortex is captured at the same position above the horn tube, which verifies the effectiveness and reliability of the numerical simulations. [ABSTRACT FROM AUTHOR]

The P–U characteristic curve of the photovoltaic (PV) cell is a single peak curve with only one maximum power point (MPP). However, the fluctuation of the irradiance level and ambient temperature will cause the drift of MPP. In the maximum power point tracking (MPPT) algorithm of PV systems, BP neural network (BPNN) has an unstable learning rate and poor performance, while the genetic algorithm (GA) tends to fall into local optimum. Therefore, a novel PV fuzzy MPPT algorithm based on an adaptive genetic simulated annealing-optimized BP neural network (AGSA-BPNN-FLC) is proposed in this paper. First, the adaptive GA is adopted to generate the corresponding population and increase the population diversity. Second, the simulated annealing (SA) algorithm is applied to the parent and offspring with a higher fitness value to improve the convergence rate of GA, and the optimal weight threshold of BPNN are updated by GA and SA algorithm. Third, the optimized BPNN is employed to predict the MPP voltage of PV cells. Finally, the fuzzy logical control (FLC) is used to eliminate local power oscillation and improve the robustness of the PV system. The proposed algorithm is applied and compared with GA-BPNN, simulated annealing-genetic (SA-GA), particle swarm optimization (PSO), grey wolf optimization (GWO) and FLC algorithm under the condition that both the irradiance and temperature change. Simulation results indicate that the proposed MPPT algorithm is superior to the above-mentioned algorithms with efficiency, steady-state oscillation rate, tracking time and stability accuracy, and they have a good universality and robustness. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a kind of heavy metal pollutant widely existing in the aquatic environment, and it is also recognized to have a highly toxic effect on fish. In this study, silver carp (Hypophthalmichthys molitrix) larvae were exposed to 0 (control), 1, 5, and 10 μg/L Hg2+ for 2 weeks. Antioxidant ability, neurotoxicity, and thyroid hormones (THs) content were evaluated. In comparison with the control, the superoxide dismutase (SOD) activity and the glutathione (GSH) activity were lower in silver carp exposed to 10 μg/L Hg2+. The lowest catalase (CAT) activity was found in the 10 μg/L Hg2+, while malondialdehyde (MDA) content was not significantly different among all groups. Compared with the control, monoamine oxidase (MAO) activity and nitric oxide (NO) content were significantly higher in the 10 μg/L Hg2+, while acetylcholinesterase (AChE) activity significantly decreased. Compared with the control, triiodothyronine (T3) content was significantly higher in the 1 μg/L Hg2+ and significantly lower in the 10 μg/L Hg2+; the 1 μg/L and 5 μg/L Hg2+ groups had significantly higher thyroxine (T4) content than the other groups. In the 1 μg/L Hg2+, the integrated biomarker response (IBR) index value was the highest. In summary, exposure to Hg could decrease the antioxidant ability, cause changes in neurotoxic parameters, and induce disorders of the thyroid hormone system in silver carp larvae. The results of this study may contribute to the understanding of the adverse effects of chronic mercury poisoning on fish. [ABSTRACT FROM AUTHOR]

In this paper, we focus on the investigation of the regime shift of the steady states, the mean first-passage time (MFPT) and the stochastic resonance (SR) for a FitzHugh–Nagumo neural system with time delay perturbed by colored cross-correlated Gaussian colored noises as well as a periodic signal. By means of a series of numerical calculations, our investigation results show that time delay, the multiplicative noise and the additive one can all produce the negative influence on the maintenance of the stability for the neuronal system; while the two self-correlation times of the internal and external noises, the noise correlation strength and its correlation time can always strengthen the stability of the biological system. As for the MFPT for the FHN system, it is observed that during the recovery process from the excited state to the resting one, we should take measures to increases the noise correlation strength, two noise self-correlation times, and reduce time delay along with the noise correlation time so as to sustain the state of excitation for neuronal cells as far as possible. With respect to the SR phenomenon, it is observed that the noise correlation strength and its correlation time, two Gaussian noise correlation times τ 1 , τ 2 can all amplify significantly the SR effect, and even stimulate the double-peaked or three-peaked phenomenon; While time delay and the additive noise will always reduce the SR effect. [ABSTRACT FROM AUTHOR]

Pullulanase is a well-known debranching enzyme that can specifically hydrolyze α-1,6-glycosidic linkages in starch and oligosaccharides, however, it suffers from low stability and catalytic efficiency under industrial conditions. In the present study, four residues (A365, V401, H499, and T504) lining the catalytic pocket of Anoxybacillus sp. AR-29 pullulanase (PulAR) were selected for site-directed mutagenesis (SDM) by using a structure-guided consensus approach. Five beneficial mutants (PulAR-A365V, PulAR-V401C, PulAR-A365/V401C, PulAR-A365V/V401C/T504V, and PulAR-A365V/V401C/T504V/H499A) were created, which showed enhanced thermostability, pH stability, and catalytic efficiency. Among them, the quadruple mutant PulAR-A365V/V401C/T504V/H499A displayed 6.6- and 9.6-fold higher catalytic efficiency toward pullulan at 60 ℃, pH 6.0 and 5.0, respectively. In addition, its thermostabilities at 60 ℃ and 65 ℃ were improved by 2.6- and 3.1-fold, respectively, compared to those of the wild-type (WT). Meanwhile, its pH stabilities at pH 4.5 and 5.0 were 1.6- and 1.8-fold higher than those of WT, respectively. In summary, the catalytic performance of PulAR was significantly enhanced by a structure-guided consensus approach. The resultant quadruple mutant PulAR-A365V/V401C/T504V/H499A demonstrated potential applications in the starch industry. [ABSTRACT FROM AUTHOR]

Enzyme engineering toward catalytic‐tetrad residues usually results in activity loss. Unexpectedly, we found that a directed evolution campaign yielded a beneficial residue A100 in KmCR (a carbonyl reductase from Kluyveromyces marxianus ZJB14056), which is a residue of catalytic tetrad and conserved according to multiple sequence alignment. Inspired by this finding, we performed saturation mutagenesis on all the four residues of catalytic tetrad of KmCR. A number of variants with improved enzymatic activities were obtained. Among them, the variant KmCR_A100S exhibited increased catalytic efficiency (kcat/KM = 47.3 s−1·mM−1), improved stereoselectivity (from moderate selectivity (deP = 66.7%) to strict (S)‐selectivity (deP > 99.5%)), and extended substrate scope, compared to those of KmCR_WT. In silico analysis showed that a relay system was rebuilt in KmCR via the beneficial residue S100. Furthermore, comparison of 11 protein engineering campaigns indicated that the beneficial position is easily overlooked due to the long distance (>10 Å) from ketone substrates. Since CRs share similar catalytic mechanism, the knowledge gained from this study has universal significance to CR engineering. [ABSTRACT FROM AUTHOR]

Enzyme engineering usually generates trade‐offs between activity, stability, and selectivity. Herein, we report semirational engineering of an aldo–keto reductase (AKR) KmAKR for simultaneously enhancing its thermostability and catalytic activity. Previously, we constructed KmAKRM9 (W297H/Y296W/K29H/Y28A/T63M/A30P/T302S/N109K/S196C), which showed outstanding activity towards t‐butyl 6‐chloro‐(3R,5S)‐dihydroxyhexanoate ((3R,5S)‐CDHH), and t‐butyl 6‐cyano‐(3R,5R)‐dihydroxyhexanoate, the key chiral building blocks of rosuvastatin and atorvastatin. Under the guidance of computer‐aided design including consensus residues analysis and molecular dynamics (MD) simulations, K164, S182, S232, and Q266 were dug out for their thermostability conferring roles, generating the "best" mutant KmAKRM13(W297H/Y296W/K29H/Y28A/T63M/A30P/T302S/N109K/S196C/K164E/S232A/S182H/Q266D). The Tm and T5015 values of KmAKRM13 were 10.4 and 6.1°C higher than that of KmAKRM9, respectively. Moreover, it displayed a significantly elevated organic solvent tolerance over KmAKRM9. Structural analysis indicated that stabilization of the α‐helixes mainly contributed to thermostability enhancement. Under the optimized conditions, KmAKRM13 completely asymmetrically reduced 400 g/l t‐butyl 6‐chloro‐(5S)‐hydroxy‐3‐oxohexanoate ((5S)‐CHOH) in 8.0 h at a high substrate to catalyst ratio (S/C) of 106.7 g/g, giving diastereomerically pure (3R,5S)‐CDHH (>99.5% d.e.P) with a space‐time yield (STY) of 449.2 g/l·d. [ABSTRACT FROM AUTHOR]

As the number of patients with metabolic hypertension (MH) is increasing, there is an essential require for global measures to prevent and treat MH. Flavonoids such as buddleoside (BUD) from Chrysanthemum indicum L. are the main pharmacological components of cardiovascular activities. Previous studies have suggested that the buddleoside-rich Chrysanthemum indicum L. extract (BUDE) can reduce blood pressure in spontaneously hypertensive rats (SHR). However, its effect on MH and how it works remains to be researched. In this study, it was observed that BUDE could lower blood pressure, improve dyslipidemia, and decrease the level of plasma LPS in MH rats. Moreover, BUDE improved intestinal flora and increased the expression of occludin and claudin-1 in the colon, and improved the pathological injury of the colon. Western bolt and qRT-PCR experiments showed that BUDE could down-regulate TLR4 and MyD88 protein and mRNA expression and inhibit phosphorylation of IKKβ, IκBα and NF-κB p65 in vessels of MH rats. These results showed that BUDE could regulate intestinal flora, improve intestinal barrier function, reduce the production and penetration of LPS, thereby inhibiting the vascular TLR4/MyD88 pathway, improving vascular endothelial function, and ultimately lowering blood pressure in MH rats. This study provides a new mechanism of BUDE against MH by inhibiting the enteric-origin LPS/TLR4 pathway. [ABSTRACT FROM AUTHOR]

In this paper, we focus on shedding light on the stochastic stability, the MFPT and stochastic resonance (SR) phenomena for a metapopulation system in the presence of time delay, the colored cross-correlated multiplicative non-Gaussian noise and the additive Gaussian colored noise. By use of the fast descent method and the approximation of the unified colored noise, the dynamical behaviors for the modified potential function and the signal-to-noise ratio (SNR) are analyzed in detail. It is discovered that the additive Gaussian colored noise, the noise correlation strength as well as its self-correlation time can all impair the stability of the population system and speed up the population decline. Conversely, the two self-correlation times of the external and internal noises can both consolidate the stability of the biological system and prolong the survival time of the population. With regard to the SNR for the metapopulation system caused by the noise terms and time delay, it is revealed that time delay, the noise correlation strength and its correlation time can all along weaken the SR phenomenon. On the contrary, two noise self-correlation times are able to amplify effectively the resonance effect. It is worth noting that the parameter of non-Gaussianity q in the SNR- τ and SNR- λ plots can initially weaken the SR phenomena and then enhance the maximum of the SNR as it is further increased. [ABSTRACT FROM AUTHOR]

In this paper, the regime shift behaviors between the prosperous state and the extinction state and stochastic resonance (SR) phenomenon for a metapopulation system subjected to time delay and correlated Gaussian colored noises are investigated. Through the numerical calculation of the modified potential function and the stationary probability density function (SPDF), one can make clearly the following results: Both multiplicative noise and noise correlation times can improve effectively the ecological stability and prolong the survival time of the system; while additive noise, time delay and noise correlation strength can weaken significantly the biological stability and speed up the extinction of the population. As for the signal-to-noise ratio (SNR), it is found that time delay, multiplicative noise and noise correlation strength can all impair the SR effect. Conversely, the two noise correlation times and additive noise are in favor of the improvement of the peak values of SNR. It is particularly worth mentioning that in the case of M = 0. 0 3 , time delay α and self-correlation time τ 2 of the additive noise display exactly the opposite effect on the stimulation of the resonant peak in the SNR– λ plots. [ABSTRACT FROM AUTHOR]

We demonstrate experimentally the simultaneous generation and detection of two types of continuous variable nonclassical states from one type-0 phase-matching optical parametric amplifcation (OPA) and subsequent two ring flter cavities (RFCs). The output feld of the OPA includes the baseband ω0 and sideband modes ω0± nωf subjects to the cavity resonance condition, which are separated by two cascaded RFCs. The first RFC resonates with half the pump wavelength ω0 and the transmitted baseband component is a squeezed state. The refected felds of the frst RFC, including the sideband modes ω0± ωf, are separated by the second RFC, construct Einstein–Podolsky–Rosen entangled state. All freedoms, including the filter cavities for sideband separation and relative phases for the measurements of these sidebands, are actively stabilized. The noise variance of squeezed states is 10.2 dB below the shot noise limit (SNL), the correlation variances of both quadrature amplitude-sum and quadrature phase-diference for the entanglement state are 10.0 dB below the corresponding SNL. [ABSTRACT FROM AUTHOR]

Due to the promising applications, the demand to enhance poly-γ-glutamic acid (γ-PGA) production while decreasing the cost has increased in the past decade. Here, xylose/glucose mixture and corncob hydrolysate (CCH) was evaluated as alternatives for γ-PGA production by Bacillus amyloliquefaciens C1. Although both have been validated to support cell growth, glucose and xylose were not simutaneously consumed and exhibited a diauxic growth pattern due to carbon catabolite repression (CCR) in B. amyloliquefaciens C1, while the enhanced transcription of araE alleviated the xylose transport bottleneck across a cellular membrane. Additionally, the xyl operon (xylA and xylB), which was responsible for xylose metabolism, was strongly induced by xylose at the transcriptional level. When cultured in a mixed medium, xylR was sharply induced to 3.39-folds during the first 8-h while reduced to the base level similar to that in xylose medium. Finally, pre-treated CCH mainly contained a mixture of glucose and xylose was employed for γ-PGA fermentation, which obtained a final concentration of 6.56 ± 0.27 g/L. Although the glucose utilization rate (84.91 ± 1.81%) was lower than that with chemical substrates, the xylose utilization rate (43.41 ± 2.14%) and the sodium glutamate conversion rate (77.22%) of CCH were acceptable. Our study provided a promising approach for the green production of γ-PGA from lignocellulosic biomass and circumvent excessive non-food usage of glucose. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate whether genetic polymorphisms in TGFB1 contribute to breast cancer (BC) susceptibility, and explore the mechanism of action. Methods: A total of 7 tagging SNPs (tSNPs) were genotyped in 1161 BC cases and 1337 age-matched controls among Chinese Han population. Bioinformatics analysis was used to predict functional SNP closely linked to tSNPs. Luciferase gene reporter assay was performed to determine the effect of genetic variants on promoter activity. DNA pull-down assay and mass spectrometry were used to identify the differentially binding proteins to genetic variants. Results: Genotyping analysis showed that rs1800469 (C>T) in the 5′ regulatory region of TGFB1 was associated with reduced BC risk. Bioinformatics analysis predicted that rs11466313 (-2389_-2391 Del/AGG) in the 5′ regulatory region of TGFB1, was closely linked to tSNP rs1800469 and could be functional. The genotyping of rs11466313 by PCR-SSCP showed that rs11466313 also conferred decreased BC risk. Luciferase assays demonstrated that rs11466313 minor allele reduced over ninefold of promoter activity compared with its major allele (p < 0.001). DNA pull-down assay and mass spectrometry revealed that rs11466313 minor allele lost the binding ability with FAM98B and HSP90B. Knocking down FAM98B but not HSP90B, the enhanced promoter activity driven by TGFB1 rs11466313 major allele was attenuated. Conclusions: This study elucidates the impact of functional polymorphism rs11466313 in the regulatory region of TGFB1 on breast cancer susceptibility and gene expression, and could be helpful for future research to determine the value of this TGFB1 variant in the clinical setting. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Echinocandin B deacylase (EBDA), from Actinoplanes utahensis ZJB-08196, is capable of cleaving the linoleoyl group from echinocandin B (ECB), forming the echinocandin B nucleus (ECBN), which is a key precursor of semisynthetic antifungal antibiotics. In the present study, molecular evolution of AuEBDA by random mutagenesis combined with site-directed mutagenesis (SDM) and screening was performed. Random mutagenesis on the wild-type (WT) AuEBDA generated two beneficial substitutions of G287Q, R527V. The "best" variant AuEBDA-G287Q/R527V was obtained by combining G287Q with R527V through SDM, which was most active at 35 °C, pH 7.5, with Km and vmax values of 0.68 mM and 395.26 U/mg, respectively. Mutation of G287Q/R527V markedly increased the catalytic efficiency kcat/Km by 290% compared with the WT-AuEBDA. [ABSTRACT FROM AUTHOR]

ω-Transaminase (ω-TA) is an attractive alternative to metal catalysts for the stereoselective amination of prochiral ketones. The narrow substrate scope of an R-ω-transaminase from Mycobacterium vanbaalenii (MvTA) limits its application in R-amine synthesis. A fluorescence-based TA activity screening system was developed to extend its substrate scope. The reactions were conducted in microtiter plates (MTPs) and displayed low background interference, high sensitivity (μM magnitude), and a wide dynamic range (ɀ-factor > 0.9). A KnowVolution campaign was performed on this enzyme, and screening ~ 8000 clones with this fluorescence-based screening system resulted in two beneficial substitutions (G68Y and F129A) and three improved variants (M3, M4, and M5). The best variant, MvTA M5 (WT+G68Y+F129A), achieved the highest catalytic efficiency (toward fluorogenic substrate NMA) which was 3.2-fold higher than that of the WT enzyme. MvTA M5 exhibited significantly enhanced activity toward six different prochiral ketones with e.e. > 99% (R). The specific activity of MvTA M5 was more than 100 times higher than that of the WT enzyme toward acetonaphthone (M5: 8.1 U/mg, WT: ~ 0.07 U/mg), and it showed the highest activity on acetonaphthone, p-ethylacetophenone, and phenylacetone. [ABSTRACT FROM AUTHOR]

We consider a binary self-attractive Bose–Einstein condensate with Rashba spin–orbit coupling (SOC) in two-dimensional (2D) free space. The formation, stability, and dynamics of vector bright solitons are elucidated through numerical analysis and variational approximation. It is found that dynamically stabilized vector bright solitons can be formed in 2D free space with appropriate parameters and ramp schemes, and its motional trajectory and stability show nontrivial behavior and strong dependence on the direction of the force generated by the SOC. Finally, the case of the periodic modulation of SOC is discussed, and an experimental protocol is also given. [ABSTRACT FROM AUTHOR]

To address the concern of intense deformation of the surrounding rock near the T-type face end formed by gob-side entry retaining, the idea of forming the L-type face end by low-pressure mining technology without pre-driving roadway is proposed, and the formation mechanism of the L-type face end and its stability and pressure behavior characteristics are studied in this paper. The results show that the roadway excavation can be canceled and that the L-type face end structure near the working face end can be formed using low-pressure mining technology without pre-driving roadway, which fundamentally eliminates the impact of advance stress on the deformation of the surrounding rock near the face end and substantially improves the stability of the surrounding rock in front of the face end. Meanwhile, on the rear side of the face end, the stress transfer path of the part roof is cut off by means of roof cutting, and a wider corner effect area is formed. Therefore, the impact of roof caving behind the working face on the deformation of surrounding rock near the L-type face end is weakened, thus significantly improving the stability of the surrounding rock. According to the engineering test, there is a certain range of the low-pressure zone of the L-type face end along the direction of the working face and the axial direction of the roadway. In the former low-pressure zone, the periodic weighting of the working face is not obvious, and the dynamic factor of the support is small; in the latter low-pressure zone, the roof-to-floor deformation of the roadway and support structure stress are both very small as well. The test results are basically consistent with the results of the theoretical analysis. The above results prove that the idea and method of forming the L-type face end using low-pressure mining technology without pre-driving roadway, thus controlling the formation of the surrounding rock near the working face end, is completely effective. [ABSTRACT FROM AUTHOR]

Even though cell–cell adhesion molecule carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is extensively studied since the discovery, the role of CEACAM1 in different cancers is not completely clarified. In the present study, we examined CEACAM1 expression and its association with patient survival in various cancers by analysis of multiple databases. Oncomine database analysis revealed that CEACAM1 expression was upregulated in lung and pancreatic cancers, but downregulated in colorectal and head and neck cancers. PrognoScan and Kaplan‑Meier analyses showed that colorectal cancer patients as well as head and neck cancer patients with high CEACAM1 expression exhibited a higher overall survival rate. STRING analysis identified CEACAM3, CEACAM8, FN1, etc. as CEACAM1 interactors. Gene alteration analysis showed that CEACAM1 mutation predominantly occurred in the N-terminal. Coexpression analysis demonstrated that CEACAM1 had distinct coexpressed genes in different cancers, but KRT protein was consistently coexpressed with CEACAM1 in diverse cancer types. All the observations supported that CEACAM1 can serve as a diagnostic marker for some cancers, such as pancreatic cancer. And high CEACAM1 expression provides a better prognosis for some cancers, such as colorectal and head and neck cancers. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Zhejiang University: Science A is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)