[Research progress in the etiology of hepatitis type E virus].

Hepatitis type E virus (HEV) is a significant infectious zoonotic disease that causes hepatitis E. The disease is primarily transmitted via the fecal-oral route through contaminated water or food and is transmissible between species and genera. The causative agent for the disease is the hepatitis type E virus, which is a member of the Hepadnaviridae family and a single-stranded RNA virus. Its 7.2 kb genome mainly contains three open reading frames (ORFs): ORF1 encodes a non-structural polyprotein that mediates viral replication and transcription; ORF2 encodes a capsid protein and free antigen that induce neutralizing antibodies; ORF3 partially overlaps with ORF2 and encodes a small multifunctional protein involved in virion formation and release. HEV has a unique dual life cycle: it is excreted into feces in the form of naked virions but circulates in the blood in the form of "quasi-enveloped" particles. The two kinds of virus particles adsorb and penetrate the host cell in distinct ways, then internalize and decapsulate to replicate the genome, thereby producing more virion and releasing it outside the cell to mediate the virus's spread. This paper reviews the morphological characteristics, genome structure, encoded proteins, and function of HEV virus-like particles in order to provide a theoretical basis for basic research and comprehensive disease prevention and control.

[Determination of creatinine and 2-thiothiazolidine-4-carboxylic acid in urine by ultra high performance liquid chromatography tandem mass spectrometry].

Objective: To establish an ultrahigh performance liquid chromatography tandem mass spectrometry method for the determination of creatinine (Cre) and 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine. Methods: In October 2020, the end-of-shift urine samples of the monitored subjects were taken, and the filtrate was prepared by centrifugation. After separated by ultra high performance liquid chromatography C18 column, acetonitrile and 0.2% acetic acid aqueous solution were used as mobile phases for gradient elution, the three quadrupole tandem mass spectrometry adopted an electrospray ion source (ESI) , the ion source temperature was 500 ℃ , and the air curtain gas flow rate was 31.4 L/min, qualitative and quantitative analysis of Cre and TTCA were carried out under the multiple reaction monitoring mode. Results: The linear range of Cre was 1.0-1 000.0 µg/L, the linear equation was y=947.3x-1605.6, and the correlation coefficient was 0.9994. The detection limit and the limit of quantitation were 0.3, 1.0 µg/L. When the addition concentrations were 50.0, 150.0 and 450.0 µg/L, the recovery rates were 92.8%-94.6% , the intra assay precisions were 3.6%-5.7% , and the inter assay precisions were 3.4%-5.4%. The linear range of TTCA was 0.1-200.0 µg/L, the linear equation was y=1164.7x-2243.9, and the correlation coefficient was 0.9991. The detection limit and the limit of quantitation were 0.03, 0.1 µg/L. When the addition concentrations were 10.0, 40.0 and 160.0 µg/L, the recovery rates were 90.8%-93.6%, the intra assay precisions were 4.6%-7.4%, and the inter assay precisions were 4.4%-6.9%. Conclusion: The sample pretreatment process of the ultra high performance liquid chromatography tandem mass spectrometry method for the determination of Cre and TTCA in urine is simple, and the continuous determination of Cre and TTCA in urine can be realized only by switching mass spectrometry parameters under the same chromatographic conditions, which is accurate and efficient, and each performance index of the method meets the determination requirements.

Parameters optimization method for the time-delayed reservoir computing with a nonlinear duffing mechanical oscillator.

Reservoir computing (RC) is a recently introduced bio-inspired computational framework capable of excellent performances in the temporal data processing, owing to its derivation from the recurrent neural network (RNN). It is well-known for the fast and effective training scheme, as well as the ease of the hardware implementation, but also the problematic sensitivity of its performance to the optimizable architecture parameters. In this article, a particular time-delayed RC with a single clamped-clamped silicon beam resonator that exhibits a classical Duffing nonlinearity is presented and its optimization problem is studied. Specifically, we numerically analyze the nonlinear response of the resonator and find a quasi-linear bifurcation point shift of the driving voltage with the driving frequency sweeping, which is called Bifurcation Point Frequency Modulation (BPFM). Furthermore, we first proposed that this method can be used to find the optimal driving frequency of RC with a Duffing mechanical resonator for a given task, and then put forward a comprehensive optimization process. The high performance of RC presented on four typical tasks proves the feasibility of this optimization method. Finally, we envision the potential application of the method based on the BPFM in our future work to implement the RC with other mechanical oscillators.

Age-Dependent Changes in the Plasma Proteome of Healthy Adults.

OBJECTIVE: Human blood plasma is a complex that communicates with most parts of the body and reflects the changes in the state of an organism. Identifying age-related biomarkers can help predict and monitor age-related physiological decline and diseases and identify new treatments for diseases. METHODS AND PARTICIPANTS: In this study, TMT-LC-MS/MS was utilized to screen differentially expressed plasma proteins in 118 healthy adults of different ages. Participants were divided into three groups: 21-30 years of age (Young), 41-50 years of age (Middle) and ≥60 years of age (Old). RESULTS: The number of differentially expressed proteins in the comparisons of Young vs Middle, Middle vs Old and Young vs Old were 82, 22 and 99, respectively. These proteins were involved in numerous physiological processes, such as "negative regulation of smooth muscle cell proliferation" and "blood coagulation". Moreover, when Young was compared with Middle or Old, "complement and coagulation cascades" was the top enriched pathway by KEGG pathway enrichment analysis. Functional phenotyping of the proteome demonstrated that the plasma proteomic profiles of young adults were strikingly dissimilar to those of the middle-aged or older adults. CONCLUSIONS: The results of this study mapped the variation in the expression of plasma proteins and provided information about possible biomarkers/treatments for different age-related functional disorders.

Characterization and identification of streptococci from golden pompano in China.

Streptococcal infections cause significant mortality and high economic losses in the fish farm industry worldwide, including in the culture of golden pompano Trachinotus ovatus L., a species gaining popularity in China. A total of 9 streptococcal strains were isolated from cage-cultured diseased golden pompano in Beihai, Zhanjing, and Shenzhen, China, between 2012 and 2014. Conventional and rapid identification systems were used to determine that the isolates were Streptococcus agalactiae, S. iniae, and S. dysgalactiae subsp. dysgalactiae. All isolates were gram-positive cocci cells in pairs or short-chain, non-motile, catalase negative, α or ß hemolytic cocci. The results of multiplex PCR assays and 16S rRNA BLAST analysis also showed that the ß hemolytic strains were S. agalactiae and S. iniae and the α hemolytic strain was S. dysgalactiae subsp. dysgalactiae, respectively. Pathogenicity assays revealed that S. agalactiae (lethal dose [LD50]: 6.38 × 10(4) CFU ml(-1)) was more virulent for golden pompano than S. iniae (LD50: 1.47 × 10(7) CFU ml(-1)) and S. dysgalactiae subsp. dysgalactiae (LD50: 2.57 × 10(6) CFU ml(-1)) when they were challenged by intraperiotoneal (i.p.) injection. The results of antibiotic susceptibility showed that all strains were extremely susceptible to cefradine, erythromycin, and cefotaxime but resistant to gentamicin, penicillin G, novobiocin, neomycin, ciprofloxacin, roxithromycin, furazolidone, enrofloxacin, norfloxacin, kanamycin, ampicillin, tetracycline, and vancomycin This is the first report of a phenomenon of golden pompano coinfection with S. agalactiae and S. iniae, which will contribute to the diagnosis and prevention of streptococcicosis.

Atom probe analysis of early-stage strengthening behaviour in an Al-Mg-Si-Cu alloy.

The strengthening of an Al-Mg-Si-Cu alloy during natural ageing and subsequent short artificial ageing was investigated using three-dimensional atom probe (3DAP) analysis and tensile testing. The contingency table and Markov chain analyses confirmed that non-random arrangements of atoms already exist after a natural ageing time of only 3.5h. Extensive use of particle analysis tools in the IVAS and PoSAP software packages revealed that whilst the commonly used minimum aggregate size (N(min)) of 10 is a reasonable choice, much more useful information about the system can be gained by additionally employing a wide range of larger and smaller N(min) values. In particular, it was found that the density and volume fraction of solute aggregates increased with increasing natural ageing time in the T4 condition. After a 0.5h artificial ageing treatment at 170 °C (designated as T6), the size, volume fraction and Mg/Si ratio of the aggregates were all found to decrease with increasing prior natural ageing time. These findings are used to discuss the detrimental effect of natural ageing, where the T6 strength has been observed to decrease rapidly with increasing prior natural ageing time before stabilising after several hours of natural ageing.

Three-dimensional atom probe characterization of alloy element partitioning in cementite during tempering of alloy steel.

Hardness measurements confirm that the martensitic microstructure of an alloy steel, AISI/SAE 4340, is significantly more resistant to softening, compared to the martensitic microstructure of a high-purity Fe-0.4% C alloy, at tempering temperatures, 300-400 degrees C, just above the temperatures where cementite replaces transition carbides in the martensitic matrix. Three-dimensional atom probe (3DAP) analyses of the 4340 steel show that Si rejection from the cementite is first detected after low-temperature tempering for times of 1 h. After 10-h tempering at 400 degrees C, Mn and Cr contents are increased, and Ni contents decreased, in cementite according to their carbide- and non-carbide-forming tendencies, respectively. The results are discussed with respect to the diffusivity of the substitutional alloying elements in the 4340 steel, and the effect that such diffusion-controlled redistribution would have on maintaining fine distributions of cementite that resist softening during tempering.

A study of the anomalous field evaporation of Sm(Co0.68 Fe0.20 Cu0.10 Zr0.02)7.5 alloy by 3D atom probe.

3D atom probe analysis of the composition of a Sm(Co0.68 Fe0.20 Cu0.10 Zr0.02)7.5 alloy was conducted by varying the probing temperature from 10.6 to 65 K and pulse fraction from 10% to 20%. It was found that the preferential evaporation of Sm occurred at 65 K, due to the very low evaporation field of Sm, 15.2 V/nm calculated by using the charge exchange model. With decreasing the specimen temperature, preferential evaporation of Sm was alleviated. The optimum analysis conditions which give reasonably good measurement of the composition were: the specimen temperature of 20 K and a pulse fraction 15%. The effects of the specimen temperature and pulse fraction on the measured composition of the alloy are discussed, based on the charge exchange model.

Polymeric nanostructures for drug delivery applications based on Pluronic copolymer systems.

The first part of this article reviewed the applications of nanostructures derived from Pluronic block copolymers that have potentials in the field of biomedical sciences. Pluronic block copolymers are used not only in drug delivery systems but also in gene and cancer therapies. In the second part, the chemical modifications of Pluronic copolymers and their applications in biomedical science were reviewed. Chemical modifications of Pluronic copolymers not only improve the properties of the polymers but they also impart more attractive properties to the block copolymers. The common systems used to modify Pluronic copolymers are polyacrylic acids, polybases, and biodegradable polyesters. Pluronics were also modified at both ends with functional groups to improve the mechanical properties of hydrogels.

Effect of enzymatic degradation on the release kinetics of model drug from Pluronic F127/poly(lactic acid) nano-particles.

Poly(lactic acid) (PLA) was successfully grafted to both ends of Pluronic F127 block copolymer (PEO-PPO-PEO) to obtain amphiphilic PLA-F127-PLA block copolymers. The effect of enzymatic degradation on the release behaviors of hydrophobic model drug 9-(methylaminomethyl)anthracene (MAMA) from PLA-F127-PLA nano-particles with vesicular structure was studied by UV-Vis spectroscopy. It was observed that the release rate of MAMA from PLA-F127-PLA nano-particles with the enzymatic degradation varied with temperature due to the activity of the enzyme with temperature. However, the enzyme concentration has negligible effect on the release rates of MAMA.

Release kinetics of hydrophobic and hydrophilic model drugs from pluronic F127/poly(lactic acid) nanoparticles.

Poly(lactic acid) (PLA) was successfully grafted to both ends of Pluronic F127 block copolymers (PEO-PPO-PEO) to obtain amphiphilic PLA-F127-PLA block copolymers. The block composition and structure of PLA-F127-PLA block copolymers were studied by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetric (DSC) and wide angle X-ray diffraction (WXRD) techniques. Data from DSC and WXRD measurements indicated that Tg and Tm of PLA blocks in PLA-F127-PLA block polymers are lower than those of PLA homopolymer. Furthermore, Tm and crystallinity of PLA blocks decrease with decreasing PLA block length in PLA-F127-PLA block copolymers. The release behaviors of both hydrophobic 9-(methylaminomethyl)anthracene (MAMA) and hydrophilic procaine hydrochloride (PrHy) model drugs from PLA-F127-PLA nanoparticles with vesicular structure in PBS solution at 37 degrees C were examined by UV spectroscopy. The release kinetics of both MAMA and PrHy model drugs from PLA-F127-PLA nanoparticles exhibit burst release characteristics, which are believed to be controlled by concentration gradient resulting from the slow hydrolytic degradation of PLA segments.

[Synthesis of benzodihydropyran derivatives and evaluation of their preliminary biological activities on bone and vascular tissues].

AIM: To screen optimal drugs against postmenopausal osteoporosis with cardiovascular protective activities. METHODS: A series of benzodihydropyran derivatives were designed and synthesized in view of comprehensive observations of raloxifene and ipriflavone. The antiosteoporosis activities of compounds a-e (10(-7) mol.L-1) on the proliferation of human osteoblast cell HOS TE85 were studied. The cardiovascular protective activities were evaluated by observing their effects on proliferation of human vascular endothelium cell ECV-304 and their protective effects on ECV-304 damaged by H2O2. RESULTS: Their structures were determined by spectrums. Compounds a, b and c (10(-7) mol.L-1) were shown to significantly help proliferation of HOS TE85. In addition, b, d and e (10(-8) mol.L-1) helped proliferation of ECV-304 significantly. Compounds b and c (10(-6) mol.L-1) showed strong protective activity on ECV-304 damaged by H2O2. Compounds b and c shifted the KCl dose-response curves to the right and decreased the maximal response. CONCLUSION: Compounds b and c showed some bone and vascular protective activities which benefit postmenopausal and cardiovascular diseases.

[Clinical and experimental study of burns treated locally with Chinese herbs].

According to the multiple pharmacological functions of Chinese herbs for treating burns, the authors selected some traditional herbs to cure the burning wound, which had not only the function of improving the local microcirculation of the burned surface and their bactericidal action, but also the function of changing the bacterial growth milieu action. Coptis chinensis 40%, Herba Taraxaci 40%, Fructus Mume 10% and Salvia miltiorrhizae 10% were boiled, infiltrated and disinfected. The mixture thus made was called as Burn II, which were applied on the burned surface daily, 97.1% of 103 patients were cured. Through the experiment of 60 rabbits burned by irons, which were divided into 6 groups (n = 10 in each group) and each 2 groups infected respectively with Bacillus pyocyaneus, Bacillus Coli and Staphylococcus Aureus, took one of each infected group as control group. After 14 days, the infected burned surfaces which were applied with Burn II daily. The results showed that the effect of Burn II was not only significant, but also its usage was not highly restricted by the medical condition.