A highly virulent canine distemper virus strain isolated from vaccinated mink in China.

An outbreak of canine distemper in 2017 in mink breeding farms (Shandong province, China) caused severe pneumonia, hardened footpads, and death in more than 5000 vaccinated animals. Sequencing of the hemagglutinin and fusion protein genes from the WH2 canine distemper virus (CDV) strain we isolated from the infected minks were clustered into the recently isolated CDV Asia-1 genotype group. The WH2 strain was distinct from the current vaccine strains, containing a novel potential N-glycosylation site in its hemagglutinin protein. It also contained amino acid mutations in the fusion protein gene (I87N, T110P and L386I), and the T110P mutation results in N-glycosylation site silencing. WH2 was highly virulent in both unvaccinated and vaccinated animals in our pathogenesis experiments. Immunohistochemistry results revealed positive staining of different organs in unvaccinated and vaccinated animals. The serum in vitro neutralizing antibody titers for the vaccinated mink group and a dog were higher for the WH2 strain than those of the HNly150520B strain (isolated from a dog). These findings indicate that the current commercial vaccines provide incomplete protection against WH2 challenge infections. Thus, a new vaccine strain is urgently needed to protect against variant CDV strains.

Generation and immunogenicity of virus-like particles based on mink enteritis virus capsid protein VP2 expressed in Sf9 cells.

Mink enteritis virus (MEV) is a parvovirus that causes acute enteritis in mink. The capsid protein VP2 of MEV is a major immunogenicity that is important for disease prevention. In this study, this protein was expressed in Spodoptera frugiperda 9 cells using a recombinant baculovirus system and was observed to self-assemble into virus-like particles (VLPs) with a high hemagglutination (HA) titer (1:216). A single-dose injection of VLPs (HA titer, 1:256) resulted in complete protection of mink against virulent MEV challenge for at least 180 days. These data suggest that these MEV VLPs could be used as a vaccine for the prevention of viral enteritis in mink.

Isolation and sequence analysis of the complete H gene of canine distemper virus from domestic dogs in Henan Province, China.

Eighteen canine distemper virus (CDV) isolates were obtained from clinical samples in Henan province, China, between 2012 and 2016. These viruses could not be recognized by 1A4, a monoclonal antibody specific for the H protein of CDV vaccine strains. The complete haemagglutinin (H) genes of all 18 isolates were sequenced, and phylogenetic analysis showed that they segregated into two clusters within the Asia-1 genotype. Moreover, the H genes of four viruses were found to lack a potential N-glycosylation site at position 309, which is the most conserved site within the Asia-1 genotype of CDV, and a novel potential N-glycosylation site (amino acids 517-519) was found in strain HL013, which has not been reported previously. These results will help in achieving a better understanding of the evolution of CDV in China.

Effects of losartan on vasomotor function and canonical transient receptor potential channels in the aortas of sinoaortic denervation rats.

Increased short-term blood pressure variability (BPV) is strongly correlated with target organ damage. However, the molecular mechanisms underlying abnormal BPV-induced organ damage and effective therapeutic targets are poorly understood. The purpose of this study was to investigate the effects of losartan on vasomotor function and canonical transient receptor potential (TRPC) channels in the aortas of rats with arterial pressure lability induced by sinoaortic denervation (SAD). SAD was performed in male Sprague-Dawley rats at the age of 10 weeks. The experiment included sham-operated (Sham), SAD, and losartan-treated SAD (SAD+Los) groups. After 8 weeks of treatment, hemodynamic parameters were measured via catheterization, thoracic aortic vasomotor functions were evaluated using a physiological vascular ring tension recording system, and TRPC1 and 6 mRNA and protein expression levels in the endothelial cells (ECs) and smooth muscle cells (SMCs) of the thoracic aorta were determined via reverse transcription polymerase chain reaction (RT-PCR) and Western-blotting, respectively. Compared with Sham rats, SAD rats exhibited significantly increased BPV, enhanced norepinephrine-induced aortic contraction, and attenuated acetylcholine-induced aortic relaxation. Both the mRNA and the protein expression levels of TRPC1 and 6 were significantly downregulated in the ECs and upregulated in the SMCs of the thoracic aortas of SAD rats. Losartan treatment prevented these SAD-induced changes. In conclusion, losartan efficiently prevented vasomotor function impairment in SAD rats by reducing BPV and regulating TRPC1 and 6 expression levels.

Improvement of Formability in Parallel Double-Branched Tube Hydroforming Combined with Pre-Forming and Crushing Processes.

In hydroforming of parallel double-branch tubes, the material entering the branch zone is obstructed by material accumulation in the main tubes and corners, which decreases the branch height. A tube hydroforming approach is combined with pre-forming and crushing (THPC) to mitigate this problem. A larger diameter tube blank is flattened for pre-forming and then subjected to radial compression for crushing. In the next step, hydroforming forms the parallel double-branch tubes. Experiments and numerical simulations are then carried out to analyze the effect of traditional tube hydroforming (TTH) and the proposed THPC process on the formability of parallel double-branch tubes. The results show that for tubes obtained via THPC, the tube burst pressure increases by 27.5% and the branch height increases 2.37-fold compared to TTH. Additionally, the flattening, pre-forming, and crushing stages cause work hardening of the tube when using the TPHC process. Flattened tubes undergo radial compression to improve the material flowing into the branch tube. The formability of parallel double-branched tubes can be improved by using the TPHC process. Consequently, tube hydroforming, combined with pre-forming and crushing, has been confirmed as a feasible forming process for fabricating parallel double-branch tubes.

Spatial spillover of local general higher education expenditures on sustainable regional economic growth: A spatial econometric analysis.

The ability of fair investments in local general higher education to drive sustainable regional economic growth is explored. Based on spatial theory, the exploratory spatial data analysis method is used to examine the spatial characteristics of local general higher education expenditures in China's 30 provinces from 2000 to 2021. The spatial Durbin model is employed to analyze the impact of education expenditures on regional economic growth. The results reveal that education expenditures had positive spatial autocorrelation. Education expenditures promoted regional economic growth, and the long-term effect was greater than the short-term effect. These expenditures also had a positive spillover effect, showing that strategic spatial interactions between provinces positively influence growth. The positive spillover effects nationwide and in the eastern region were significantly greater than the direct effect, whereas the spillover effects in both the middle and western regions were negative.

Nitrogen Dense Distributions of Imidazole Grafted Dipyridyl Polybenzimidazole for a High Temperature Proton Exchange Membrane.

The introduction of basic groups in the polybenzimidazole (PBI) main chain or side chain with low phosphoric acid doping is an effective way to avoid the trade-off between proton conductivity and mechanical strength for high temperature proton exchange membrane (HT-PEM). In this study, the ethyl imidazole is grafted on the side chain of the PBI containing bipyridine in the main chain and blended with poly(2,2'-[p-oxydiphenylene]-5,5'-benzimidazole) (OPBI) to obtain a series of PBI composite membranes for HT-PEMs. The effects of the introduction of bipyridine in the main chain and the ethyl imidazole in the side chain on proton transport are investigated. The result suggests that the introduction of the imidazole and bipyridine group can effectively improve the comprehensive properties as HT-PEM. The highest of proton conductivity of the obtained membranes under saturated phosphoric acid (PA) doping can be up to 0.105 S cm-1 at 160 °C and the maximum output power density is 836 mW cm-2 at 160 °C, which is 2.3 times that of the OPBI membrane. Importantly, even at low acid doping content (~178%), the tensile strength of the membrane is 22.2 MPa, which is nearly 2 times that of the OPBI membrane, the proton conductivity of the membrane achieves 0.054 S cm-1 at 160 °C, which is 2.3 times that of the OPBI membrane, and the maximum output power density of a single cell is 540 mW cm-2 at 160 °C, which is 1.5 times that of the OPBI membrane. The results suggest that the introduction of a large number of nitrogen-containing sites in the main chain and side chain is an efficient way to improve the proton conductivity, even at a low PA doping level.

Feline herpesvirus infection and pathology in captive snow leopard.

Feline herpesvirus type 1 (FHV-1) is a common causative agent of domestic cats' rhinotracheitis in domestic cats, and it increasingly threatens wild felids worldwide. The endangered snow leopard (Panthera uncia) belongs to the family Felidae, and it is the top predator on the Tibetan Plateau. Here we report the identification and isolation of FHV-1 from three dead captive snow leopards that presented with sneezing and rhinorrhea. To explore the relationship between FHV-1 and their deaths, organs and nasal swabs were collected for histopathology, viral isolation and sequence analysis. The results revealed that all three snow leopards were infected with FHV-1. The first animal died primarily of cerebral infarction and secondary non-suppurative meningoencephalitis that was probably caused by FHV-1. The second animal died mainly of renal failure accompanied by interstitial pneumonia caused by FHV-1. The cause of death for the third animal was likely related to the concurrent reactivation of a latent FHV-1 infection. The gD and gE gene sequence alignment of the isolated FHV-1 isolate strain revealed that the virus likely originated from a domestic cat. It was found that FHV-1 infection can cause different lesions in snow leopards than in domestic cats and is associated with high risk of disease in wild felids. This suggests that there should be increased focus on protecting wild felids against FHV-1 infections originating from domestic cats.

Direct Ink Writing of Phenylethynyl End-Capped Oligoimide/SiO2 to Additively Manufacture High-Performance Thermosetting Polyimide Composites.

The three-dimensional (3D) printing of a SiO2-filled thermosetting polyimide (SiO2@TSPI) composite with outstanding performance is realized via the direct ink writing (DIW) of polyamide acid (PAA) composite ink and thermal treatment conducted thereafter. The composite ink consists of phenylethynyl-terminated PAA and silica nanoparticles, where the SiO2 nanoparticles serve as the rheology modifier that is necessary for the DIW technique to obtain self-supporting feedstock during 3D printing and the reinforcement filler that is used to enhance the performance of the final composite. As a result, printed parts with complex geometry and robust thermal stability are obtained. Due to the extrusion-based DIW technique, the printed structures exhibit anisotropic mechanical strength that highly depends on printing roads. This simple and convenient means of realizing 3D structures of thermosetting polyimides is a promising strategy in aerospace and other fields.

A canine-derived chimeric antibody with high neutralizing activity against canine parvovirus-2.

Canine parvovirus-2 (CPV-2) infection causes serious multisystemic disease in dogs and many animal species worldwide. Previously, a monoclonal antibody (MAb) of CPV-2, 10H4, showed high neutralizing activity and therapeutic effect against CPV-2 in dogs. However, the application of mouse MAb is limited in other animals due to immune rejection. Here, the variable regions of the heavy and light chains of 10H4 were cloned and ligated with constant canine antibody regions to produce a canine-derived chimeric MAb 11D9, in a CHO-S cell expression system. The cell supernatant of the CHO cell line 11D9 exhibited a HI titer of 1:2560 against all the variants of CPV-2 (new CPV-2a, new CPV-2b, and CPV-2c), and had the same average neutralization titer as the new CPV-2a (1:11,046.5) and new CPV-2b (1:11,046.5) variants, which was slightly higher than that of CPV-2c variants (1:10,615.7). In animal experiment, the treatment of chimeric MAb 11D9 had a high therapeutic effect in beagles infected with the new CPV-2a. Overall, the canine-derived chimeric MAb 11D9 produced by CHO-S cells showed a high HI and neutralization titer against CPV-2 and the therapeutic effects against the new CPV-2a in beagles, providing potential for the prevention or treatment of CPV-2 infections in dogs.

Replication, pathogenicity, and transmission of SARS-CoV-2 in minks.

Minks are raised in many countries and have transmitted severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to humans. However, the biologic properties of SARS-CoV-2 in minks are largely unknown. Here, we investigated and found that SARS-CoV-2 replicates efficiently in both the upper and lower respiratory tracts, and transmits efficiently in minks via respiratory droplets; pulmonary lesions caused by SARS-CoV-2 in minks are similar to those seen in humans with COVID-19. We further found that a spike protein-based subunit vaccine largely prevented SARS-CoV-2 replication and lung damage caused by SARS-CoV-2 infection in minks. Our study indicates that minks are a useful animal model for evaluating the efficacy of drugs or vaccines against COVID-19 and that vaccination is a potential strategy to prevent minks from transmitting SARS-CoV-2.

How Incivility and Academic Stress Influence Psychological Health Among College Students: The Moderating Role of Gratitude.

Many students suffer from academic stress and uncivil behaviors at colleges and there is a need to identify to what extent these negative phenomena might impact students' mental health. The main purpose of this study is to examine the relationships between incivility, academic stress, and psychological health, as well as investigate the moderating role of gratitude. The study design of this research is cross-sectional. The final sample consisted of 895 university students in China; The Statistical Package for the Social Sciences (SPSS) version 22 was utilized to conduct statistical analysis. Sample t-tests were used to examine whether there were gender differences in terms of four continuous variables: incivility, stress, gratitude, and psychological wellbeing. We also used multiple hierarchical linear regression analysis to test the relationships between the aforementioned four variables and the moderating effect of gratitude. The results of our study indicate that academic stress and incivility are positively associated with psychological distress, and gratitude moderates the relationship between incivility and psychological distress. However, no significant moderating effect of gratitude was found in the relationship between academic stress and psychological distress.

Enhanced Optical Fiber for Distributed Acoustic Sensing beyond the Limits of Rayleigh Backscattering.

We report on engineered fibers with enhanced optical backscattering that exceeds Rayleigh scattering limits by more than one order of magnitude. We measure attenuation less than 0.5 dB/km from 1,300 to 1,650 nm. By controlling the enhanced backscatter over a 1.5-km length, we compensate for this attenuation, resulting in a higher backscatter signal at the end of the fiber. We demonstrate that the scattering strength may be stabilized for operation at temperatures above 200°C for at least 3 weeks. We show that the deleterious signal distortion due to the Kerr nonlinearity is within 10% of standard fiber. We then report on the use of these fibers in distributed acoustic sensing (DAS) measurements. A significant increase in acoustic signal-to-noise ratio leads to the possibility of improved spatial resolution in the enhanced fiber DAS system.

Molecular and serological investigation of cat viral infectious diseases in China from 2016 to 2019.

In order to analyse the prevalence of cat viral diseases in China, including feline parvovirus (FPV), feline calicivirus (FCV), feline herpesvirus 1 (FHV-1), feline leukaemia virus (FeLV), feline immunodeficiency virus (FIV) and feline infectious peritonitis virus (FIPV), a total of 1,326 samples of cats from 16 cities were investigated from 2016 to 2019. Collectively, 1,060 (79.9%) cats were tested positive for at least one virus in nucleotide detection, and the positive rates of cat exposure to FeLV, FPV, FHV-1, FCV, FIV and FIPV were 59.6%, 19.2%, 16.3%, 14.2%, 1.5% and 0.5%, respectively. The prevalence of FHV-1 and FPV was dominant in winter and spring. Cats from north China showed a higher positive rate of viral infection than that of cats from south China. The virus infection is not highly correlated with age, except that FPV is prone to occur within the age of 12 months. In the serological survey, the seroprevalences of 267 vaccinated cats to FPV, FCV and FHV-1 were 83.9%, 58.3% and 44.0%, respectively. Meanwhile, the seroprevalences of 39 unvaccinated cats to FPV, FCV and FHV-1 were 76.9% (30/39), 82.4% (28/34) and 58.6% (17/29), respectively. This study demonstrated that a high prevalence of the six viral diseases in China and the insufficient serological potency of FCV and FHV-1 remind the urgency for more effective vaccines.

The Relationship between Challenge and Hindrance Stressors and Emotional Exhaustion: The Moderating Role of Perceived Servant Leadership.

Schoolteachers worldwide are facing stressful work conditions with heavy responsibilities. Stress may contribute to psychological disorders and physical health issues. The purposes of this study were (1) to investigate whether both challenge and hindrance stressors are positively associated with emotional exhaustion among Chinese schoolteachers and (2) to examine whether perceived servant leadership moderates the effects of challenge and hindrance stressors on emotional exhaustion. This study was cross-sectional in nature. A sample of 2636 schoolteachers was elicited from schools in South China. Research data were collected in the fall semester of 2019 via WeChat®. Descriptive statistics and inter-correlations were conducted using SPSS 21. Confirmatory factor analysis was applied to test measurement models to determine convergent and discriminant validities using Mplus 7.4. Hierarchical multiple regression was performed to test proposed hypotheses using SPSS 21. The study results demonstrated that both challenge and hindrance stressors were positively related to emotional exhaustion among schoolteachers in Chinese schools. It was also indicated that, while perceived servant leadership buffers the relationship between challenge stressor and emotional exhaustion, it enhances the relationship between hindrance stressor and emotional exhaustion. Implications and limitations are also provided.

Molecular epidemiological survey of canine parvovirus in domestic dogs in four provinces, China.

Canine parvovirus (CPV) can cause severe disease in animals, especially in dogs, and continuously generates new variants. In this study, the complete VP2 genes of 59 CPV isolates from clinical diseased dogs between 2015 and 2016 in 4 Chinese provinces were sequenced and analyzed. The results showed that new CPV-2a was still the prominent CPV genotype, followed by CPV-2c and new CPV-2b. CPV-2c with Ala5Gly and Gln370Arg mutations was first detected in Henan, Guangxi and Jiangsu provinces in China. A phylogenetic tree based on VP2 sequences showed that all isolates in this study formed a close lineage which separated from foreign isolates. The above results indicated that point mutations in VP2 were constantly occurring along with the widespread of CPV in China.

Genetic characterization of parvoviruses in domestic cats in Henan province, China.

Feline panleukopenia virus (FPV) and canine parvovirus (CPV) infections are highly contagious and cause serious enteric diseases, with high fatality rates of cats and dogs. Given the importance of cats as a potential source of genetic diversity for parvoviruses, parvovirus strains detected in cats with gastroenteritis signs were analysed, and molecular characterisation, sequence analysis and phylogeny were evaluated on the VP2 gene. The results showed that FPV, new CPV-2a, and CPV-2 are co-circulating in the cat population in Henan province of China. Moreover, CPV-2 strains (F2016020, and F2016021) with Ser297Ala substitution in VP2 protein was for the first time detected in cats with clinical gastroenteritis. This study provided new important findings about the evolutionary of parvovirus infection in domestic cats.

[Changes of the new gaseous transmitter H2S in patients with coronary heart disease].

OBJECTIVE: To investigate the changes of plasma hydrogen sulfide (H(2)S) in patients with coronary heart disease (CHD). METHODS: Plasma H(2)S levels were measured in 40 patients with CHD and 17 angiographically normal patients by sulfide-sensitive electrodes, and the variation of plasma H(2)S levels was analyzed in different clinical types of CHD and in different types of coronary artery lesions. The association of plasma H(2)S levels with the risk factors of CHD was also analyzed. RESULTS: Plasma H(2)S levels were significantly lowered in CHD patients in comparison with that in angiographically normal control subjects (26.10+/-14.27 micromol/L vs 51.74+/-11.94 micromol/L, P<0.001). In CHD patients, plasma H(2)S levels in unstable angina patients (UAP, 23.60+/-14.41 micromol/L) and acute myocardial infarction patients (AMI, 19.98+/-7.516 micromol/L) were significantly lower than that in stable angina patients (SAP, 38.41+/-14.53 micromol/L, P<0.05). No significant difference in plasma H(2)S levels was found between CHD patients with double-vessel and multi-vessel lesions (16.91+/-7.98 vs 18.39+/-7.78 micromol/L, P>0.05), but the two groups of patients had significantly lower plasma H(2)S levels than patients with single-vessel involvement (33.04+/-15.01 micromol/L, P<0.05 and P<0.01, respectively). Plasma H(2)S level was significantly lower in CHD patients with coronary artery occlusion than in patients with simple stenosis (19.04+/-9.55 vs 28.24+/-14.85 micromol/L, P<0.05). Among the CHD patients, H(2)S levels were significantly lower in smokers than in non-smokers (27.54+/-10.37 vs 32.24+/-15.77 micromol/L, P<0.05), also lower in hypertensive patients than in normotensive patients (20.36+/-8.69 vs 33.77+/-15.86 micromol/L, P<0.01). Plasma H(2)S levels showed a significant inverse correlation with blood glucose (r=-0.493 6, P=0.001 6), but there were no significant correlations with sex, age, cholesterol, triglyeride, TC, low-density lipoprotein, high-density lipoprotein, or body mass index. CONCLUSION: Decreased plasma H(2)S levels may correlate with the severity of CHD and changes of the coronary artery, and may implicate the risk factors of CHD such as smoking, hypertension, and high blood glucose.

[Dynamic changes in plasma adrenomedullin levels and effect of enalapril intervention in diabetic rats].

OBJECTIVE: To observe the dynamic changes of plasma adrenomedullin (ADM) levels and the effect of enalapril intervention in diabetic rats. METHODS: Fifty-two wistar rats were grouped into 1- and 3-month groups (7 each), both including a control and a streptozotocin-induced diabetic group. The 5-month group was divided into control, diabetic and enalapril-treatment diabetic groups (8 each, the last group receiving oral enalapril treatment at the daily dose of 2 mg/kg from the first to the fifth month after diabetes induction). Blood samples were collected from the heart of the rats at the end of 1, 3 and 5 months for determination of plasma ADM concentrations radioimmunoassay. RESULTS: Plasma ADM levels were significantly higher in diabetic rats than in the corresponding control rats in 1- and 3-month groups. ADM levels in the diabetic rats of 5-month group were significantly decreased in comparison with that of 1- and 3-month groups. In 5-month group, plasma ADM levels of enalapril-treated diabetic rats elevated significantly in comparison with that in the control rats and the diabetic rats without enalapril treatment. CONCLUSION: ADM may play an important role in the pathophysiology of diabetes.