[Determination of 8 N-nitrosamines in the workplace air by GC-MS/MS method].

Objective: To establish a method for the determination of eight N-nitrosamines (N-nitrosodimethylamine, N-nitrosodimethylamine, N-nitrosomethylmethylamine, N-nitrosodibutylamine, N-nitrosopropylamine, N-nitrosomorpholine, N-nitrosodianiline and N-nitrosopiperidine) in the air of workplace by gas chromatography-tandem mass spectrometry (GC-MS/MS) . Methods: From January to August 2023, eight N-nitrosamines in the air of workplace were collected by ThermoSorb/N column, eluted with 4 ml methanol-dichloromethane (1∶1 volume ratio), separated by VF-624 ms capillary column, detected by multiple reaction monitoring mode and quantified by external standard method. The detection limit and precision of the method were also analyzed. Results: The linear range of the method for the determination of eight N-nitrosamines was 1.0-20.0 µg/L, the correlation coefficient was 0.9993-0.9999, the detection limit was 0.051-0.132 µg/L, and the minimum quantitative concentration was 0.030-0.078 µg/m(3) (calculated by collecting 22.5 L of air sample and eluting with 4.0 ml stripping liquid). The within-run precisions were 2.05%-6.89% and the between-run precisions were 2.41%-8.26%. The desorption rates were 67.20%-102.60%. The sample can be kept at least 7 days at 4 ℃. Conclusion: GC-MS/MS method for the determination of eight N-nitrosamines in workplace air has high sensitivity and good precision, and can accurately determine the content of eight N-nitrosamines in workplace air.

[Determination of phenylglyoxylic acid and mandelic acid in urine by ultra high performance liquid chromatography tandem mass spectrometry].

Objective: To develop a method for the analysis of phenylglyoxylic acid (PGA) and mandelic acid (MA) in urine by ultra-high performance liquid chromatography tandem mass spectrometry. Methods: The study was conducted in April 2022. Urine samples were directly diluted with the initial mobile phase, separated by Waters HSS T3 column after passing through the membrane, and analyzed under negative ionization mode (ESI(-)) and multiple reaction monitoring (MRM) conditions, the contents of PGA and MA in human urine were quantitatively determined by external standard method. Results: The determination of PGA and MA showed a good linear relationship within the range of 10-1000 ng/ml, with a correlation coefficient of 0.9999. The linear regression equation of PGA was y=1141.4x+2157.3, the detection limit and lower limit of quantification of the method were 0.081 ng/ml and 0.269 ng/ml, and the recovery rate was 90.47%-99.83%. The linear regression equation of MA was y=62.8x+140.3, the detection limit and lower limit of quantification of the method were 0.551 ng/ml and 1.836 ng/ml, and the recovery rate was 92.75%-101.09%. The intra and inter batch precision of PGA and MA were both<5%. Conclusion: An ultra-high performance liquid chromatography tandem mass spectrometry method for the analysis of PGA and MA in urine was established.The sample pretreatment operation is simple, and the accuracy and precision of the method meet the standard requirements. It can be used for monitoring and evaluating PGA and MA in urine of the general population and occupational contact population.

[Determination of acetone in urine by headspace gas chromatography-mass spectrometry].

Objective: To establish a method for determination of acetone in urine by headspace gas chromatography-mass spectrometry. Methods: From March to June 2021, the 3.0 ml urine sample was placed in a headspace bottle with 4.0 g of anhydrous sodium sulfate and sealed. Equilibration time was 30 min at 85 ℃. The separation was carried out on a DB-5MS column. The urine sample was detected by mass spectrometry and quantified by external standard method. Results: The method for the determination of acetone in urine by headspace gas chromatography-mass spectrometry had good linearity in the range of 51.2-1024.0 µg/L, and the correlation coefficient was 0.9995. The detection limit and the lower limit of quantification of acetone were 16.4 µg/L and 54.6 µg/L. The average recoveries of samples ranged from 94.9% to 96.8%. The intra-assay precision and inter-assay precision were both less than 10%. Samples can be stored at least 7 d at 4 ℃ or -20 ℃. Conclusion: This method has simple sample preparation and high sensitivity. It can be used for monitoring and evaluation of urinary acetone in the general population and occupationally exposed populations.

[A non-targeted metabolomics study on serum of occupational people exposed with nanometer titanium dioxide particles (TiO(2)-NPs)].

Objective: To study the changes of serum metabolic profile of occupational people exposed with nanometer titanium dioxide particles (TiO(2)-NPs), and to explore the biomarkers and injury mechanism of TiO(2)-NPs health effects. Methods: From June 2020 to June 2021, a TiO(2)-NPs production enterprise was selected as the research site by a typical sampling method, 64 people in the TiO(2)-NPs exposure group were selected from the enterprise, and 62 people of the logistics administrative staff in the same enterprise were selected as the control group, and blood samples were collected using non-anticoagulant blood collection tubes. After the samples were methanol-precipitated, the untargeted metabolomic data was collected by ultra-high performance liquid chromatography time-of-flight mass spectrometry, and biomarkers were screened and metabolic pathway analysis was performed. Results: 46 different metabolites were screened out by P<0.05 and variable importance projection index (VIP) value >1, mainly including glycerides, sphingomyelin, glycerophospholipid, fatty acyl, etc.; By ROC analysis to determine 3-hydroxy-4, 5-dimethyl-2 (5H) - furanone, 4-aminobiphenyl, heptanoylcarnitine, Hexadecanedioic acid mono-L-carnitine ester, Ibutilide, LysoPA (18∶1 (9Z) /0∶0), LysoPC (18∶0), PC (16∶0/16∶0), PC (16∶0/20: 4 (5Z, 8Z, 11Z, 14Z) ), PC (P-18∶1 (9Z) /P-18∶1 (9Z) ) 10 candidate biomarkers; involving changes in 4 metabolic pathways, namely glycerophospholipid metabolism, sphingolipid metabolism, phenylalanine, tyrosine and tryptophan acid biosynthesis, linoleic acid metabolism. Conclusion: Occupational exposure to TiO(2)-NPs has a significant impact on serum metabolic profiles.

[Relationships between lead-induced learning and memory impairments and gut microbiota disturbance in mice].

Objective: To explore the effect of lead exposure on the neurobehavior and gut microbiota community structure in mice. Methods: In August 2019, 64 C57BL/6 mice were randomly divided into 4 groups: control group (0 ppm) , low lead exposure group (20 mg/l) , medium lead exposure group (100 mg/l) and high lead exposure group (500 mg/l) . During the experiment, they were free to eat and drink. The drinking water of the lead exposure group was mixed with lead acetate, and sodium acetate was added in the control group. After 10 weeks of exposure, the Morris water maze was used to test the learning and memory ability of each group of mice, and then they were sacrificed for sampling. ICP-MS was used to detect lead content in whole blood and brain tissue. ELISA was used to determine the level of IL-1ß in mouse serum. 16S rRNA sequencing was used to detect the structural diversity of the intestinal flora in feces, and then the correlation between the flora and behavior indicators was analyzed. Results: In the Morris water maze experiment, compared with the control group, there was no significant difference in the body weight and swimming speed of the mice in the lead exposure groups. The escape latency of the mice in the 100 mg/l and 500 mg/l dose groups was prolonged, and the number of platform crossings decreased (P<0.05) ; meanwhile, the staying time of the mice in the 500 mg/l Pb-treated group in the target quadrant was lower than that of the control group, and the difference was statistically significant (P<0.05) . Compared with the control group, the blood lead content of the mice in each lead exposure group was significantly increased, and the brain lead content of mice in the 500 mg/l dose group was significantly elevated (P<0.05) . The serum IL-1ß levels of mice in each lead exposure group were higher than those of the control group (P<0.05) . At the phylum level, the relative abundance of the Proteobacteria phylum in all of Pb-treated groups was significantly increased (P<0.05) ; at the genus level, Allobaculum, Desulfovibrio, Lachnospiraceae_NK4A136_group, Turicibacter and Ureaplasma were significantly increased (P<0.05) . Among them. The relative abundance of Desuffaoibrio, Turici bacter, and Ureaplasma was negatively correlated with the residence time of mice in the quadrant of the platform (r=-0.32, -0.29, -0.44, P<0.05) . Conclusion: Lead exposure induced learning and memory impairments in mice, which may be related to the disturbance of the gut microbiota.

[Effect of shift work on menopausal age and menstruation span of professional women].

Objective: To explore the relationship between shift work and menopausal age and menstruation span of retired women. Methods: During July 2017 and October 2018, the research was performed by using cluster sampling in nine districts of Shenzhen City to select all permanent residents (3518 people) with Shenzhen household registration in which was equal to or over 60 years old from the Community Health Service Centers. The data of age, marital status, menopausal age, smoking, drinking, shift experience and shift years were collected. The relationship between shift work and menopausal age as well as menstruation span of professional women were analyzed by multivariate linear regression model. Results: There were 359 people (10.2%) in the shift experience group, the menopausal age was (49.71±3.63) years, and the menstrual period was (34.27±3.92) years. The non-shift experience group were 3159 people (89.8%) , the menopausal age was (50.20±3.60) years, and the menstrual period was (34.86±4.13) years. The differences of menopausal age and menstrual years between the two groups were statistically significant (P<0.05) . After adjusting for factors such as passive smoking and drinking, the results of the multiple linear regression model showed that menopausal age, menstrual years were negatively correlated with shift work (ß=-0.493, -0.575, P<0.05) . Conclusion: Shifts are related to women's menopausal age and menstrual years, and attention should be paid to the impact of work intensity and circadian rhythm on the occupational health of female employees.

[A non-targeted metabolomics study on urine of occupational exposure people with titanium dioxide nanoparticles].

Objective: To investigate the effects of titanium dioxide nanoparticles (TiO(2) NPs) on urine metabolites in occupationally exposure people based on metabolomics technology, and to explore the mechanism of early health effects of TiO(2) NPs on occupational exposure. Methods: In October 2019, the TiO(2) NPs occupational exposure population was selected as the research object, of which 64 people were in the exposure group who had been engaged in TiO(2) NPs exposure positions for more than 1 year; the control group was 62 people, who were logistics administrative staff of the same company. The urine of the research subjects before class was collected, using the ultra-high performance liquid chromatography time-of-flight mass spectrometer to collect the metabolism data of the urine, Progenesis QI software for data preprocessing and metabolite identification, SIMCA-P software for the principal component analysis of the data and potential biomarkers screening, MetaboAnalyst 4.0 software for metabolic pathway enrichment analysis. Results: The urine metabolism profile of workers in the exposure group was different from the control group, and 44 potential biomarkers were screened and identified. These potential biomarkers were significantly enriched in three pathways (P<0.05) , namely D-arginine and D-ornithine metabolism pathway, nitrogen metabolism pathway and D-glutamine and D-glutamate metabolism pathways. Conclusion: The occupational exposure of TiO(2) NPs can affect the concentration of metabolites in people urine and metabolic pathways, which provides a direction for the study of occupational hazard mechanisms of TiO(2) NPs and the monitoring of health risks.

[Metabolomics study of urine with Benzene, Toluene and Xylene combined exposure based on ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry].

Objective: To study the effects of combined occupational exposure of benzene, toluene, and xylene on human metabolism at an overall level, and to screen biomarkers related to the combined occupational exposure of benzene, toluene, and xylene, and to explore the mechanism of early health effects preliminarily caused by combined occupational exposure of benzene, toluene, and xylene by identification of biomarkers and retrieval of metabolic pathways. Methods: A shoe-making company was selected as the research site. Twenty subjects for the exposed group and the control group were selected separately, and urine of the subjects was collected. The metabolic profiles of the samples were collected by liquid chromatography time-of-flight mass spectrometry, and professional metabolomics and multivariate statistical analysis software were used to establish PCA and OPLS-DA analysis models to screen potential biomarkers and identify biomarkers. Finally, based on the dynamic changes and trends of potential biomarkers between groups, the mechanism of body damage caused by benzene, toluene, and xylene was initially explored. Results: Urine metabolomics analysis showed that the metabolic profile of urine samples of the benzene, toluene, and xylene combined exposure group was different from that of the control group. 27 potential biomarkers that were closely related to the combined exposure of benzene, toluene, and xylene were screened and identified. These potential biomarkers were enriched in 16 metabolic pathways, of which 3 pathways were significantly enriched (P<0.05) , respectively, lysine metabolism, amino sugar metabolism, and nucleotide sugar metabolism. Conclusion: The metabonomics method can well reflect the changes in the metabolome of urine samples in the occupational population after the combined exposure of benzene, toluene, and xylene, which will help us better evaluate the risk of combined exposure of benzene, toluene, and xylene and prevent and control their health risks.

[The application of amodified scalp retractor in the craniotomy for intracranial aneurysms].

Objective: To investigate the application of a modified scalp retractor in the craniotomy for intracranial aneurysms withlateral supraorbital approach. Methods: From January 2019 to April 2020, a total of 32 patients with anterior circulation aneurysms clipping by superior lateral orbital approach were selected from Beijing Tiantan Hospital and Peking University International Hospital. The subjects were randomly divided into the traditional scalp retractor group and the modified scalp retractor group utilizing a random number table, with 16 patients in each group. The number of intraoperative retractor adjustment, incision length, postoperative scalp necrosis rate, postoperative wound healing grade, postoperative neurosurgical satisfaction score and patients' satisfaction score for incision were compared between the two groups. Results: The number of retractor adjustment in the modified scalp retractors group was significantly less than that in the traditional scalp retractor group (10.1±2.2 vs 14.2±3.6, P<0.05) . Incision length was also significantly shorter than that of the conventional scalp retractor group ( (10.1±1.0) cm vs (13.9±0.9) cm, P<0.05) .Neurosurgeons were significantly more satisfied with modified scalp retractors than the traditional scalp retractors (8.1±0.9 vs 6.0±0.9, P<0.05). There was no significant difference in postoperative scalp necrosis rate between two groups (P>0.05). Conclusion: The modified scalp retractor group is superior to the traditional scalp retractor group in the craniotomy for intracranial aneurysms with later supraorbital approach, with shorter in cision, less retractor adjustment and shorter surgical time.

[Determination of Cortisol in Saliva by Liquid Chromatography Tandem Mass Spectrometry].

Objective: To establish a liquid chromatography tandem mass spectrometry method to determine the cortisol in saliva. Methods: Take 0.5 ml saliva sample into a 2 ml centrifuge tube, add excess sodium chloride and 1ml acetonitrile to it, then vortex for 3 min, centrifuge for 10 min at 15 000 r/min, and take 800 µl of the upper layer to another centrifuge tube. Finally, the sample was concentrated by a vacuum concentrator and brought to 200 µl with the initial mobile phase. Then, the sample was analyzed by liquid chromatography tandem mass spectrometry. The target compound was quantified by external standard curve method. Results: The linear range of the method was 0.02-5.00 ng/ml, r=0.999 9, the method limit of the detection was 0.002 ng/ml, the method limit of quantitative was 0.02 ng/ml, and the spiked recoveries were 89.60%-98.60%. The intra-assay precision was 1.90%-3.30%, and the inter-assay precision was 4.20%-9.00%; samples could be stored at -20 °C for at least 14 days. The determination of cortisol could not be interfered by other endogenous substances in the sample. Conclusion: The method is simple in pretreatment, high sensitivity, good reproducibility and good recovery, and it is suitable for the quantitative analysis of cortisol in saliva for normal and occupationally stressed populations.

[Determination of seven urinary metabolites of benzene, toluene and xylene by ultra-high performance liquid chromatography-triple quadrupole mass spectrometry].

Objective: To develop a method using ultra-high performance liquid chromatography-triple quadrupole mass spectrometry to determine the urinary metabolites of benzene, toluene and xylene. The selected metabolites are S-phenylmercapturic acid (S-PMA) , trans, trans-muconic acid (t, t-MA) , 8-hydroxy-2 deoxyguanosine (8-OHdG) , hippuric acid (HA) , 2-methylhippuric acid (2-MHA) , 3-methylhippuric acid (3-MHA) and 4-methylhippuric acid (4-MHA) . Methods: The urine sample was pretreated using methanol to precipitate the proteins. HSS T3 chromatographic column was used to separate the metabolites. The mass spectrometric acquisition was carried out using multiple reaction monitoring (MRM) after ionization with ESI source. External standard method was used for quantification. Results: All the standard curves showed good linear relation, and r of the seven metabolites was all above 0.999. The detection limits and quantitative limits of the seven metabolites were 0.01-500 ng/ml and 0.02-1 000 ng/ml (based on the actual dilution ratio) , respectively. The average spiked recoveries of four loadings ranged from 85.8% to 109.9%. The intra-day and inter-day precisions were 0.2%-4.5% and 0.6%-9.5%, respectively. The samples can be kept for at least 14 days at both 4 ℃ and -20 ℃. Conclusion: This method is simple, rapid and highly sensitive with low cost, and its accuracy, precision and stability can meet the daily test requirements. It can be applied for the determination of urinary S-PMA, t, t-MA, 8-OHdG, HA, 2-MHA, 3-MHA and 4-MHA for the occupational population exposed to benzene, toluene and xylene.

ICTV Virus Taxonomy Profile: Hepeviridae.

The family Hepeviridae includes enterically transmitted small non-enveloped positive-sense RNA viruses. It includes the genera Piscihepevirus, whose members infect fish, and Orthohepevirus, whose members infect mammals and birds. Members of the genus Orthohepevirus include hepatitis E virus, which is responsible for self-limiting acute hepatitis in humans and several mammalian species; the infection may become chronic in immunocompromised individuals. Extrahepatic manifestations of Guillain-Barré syndrome, neuralgic amyotrophy, glomerulonephritis and pancreatitis have been described in humans. Avian hepatitis E virus causes hepatitis-splenomegaly syndrome in chickens. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Hepeviridae, which is available at www.ictv.global/report/hepeviridae.

[Research progress of weight-adjusted waist index and the association with adverse health outcomes].

Anthropometric indexes play a crucial role in identifying obesity. However, as an internationally commonly used indicator of obesity diagnosis, BMI has limitations in distinguishing lean body mass from fat mass. The weight-adjusted waist index (WWI), a novel anthropometric index, assesses adiposity through standardized waist circumference for weight, which presents an excellent capacity to predict the morbidity and mortality risks of various diseases. However, research on WWI is still in the exploratory stage, and there is a lack of unified standards for using this indicator to determine obesity. In addition, its potential application in children and adolescents also urgently needs to be explored. Therefore, this article comprehensively summarizes and compares the distinctive characteristics between WWI and other obesity-related anthropometric indexes. Bibliometric methods are used to analyze the hotspots and trends of WWI-related research, and we focus on discussing the value of WWI in predicting adverse health outcomes, including cardiovascular disease, diabetes, liver and kidney diseases. We aim to promote the application of WWI in a broader field and fully demonstrate its important public health significance and broad application prospects.

[Evaluation of effects of comprehensive intervention based on key persons on AIDS-related high-risk behaviors in male sex workers in entertainment venues].

Objective: To evaluate the effect of comprehensive intervention model based on key persons in entertainment venues on the incidence of AIDS-related high-risk behaviors in male sex workers (MSW). Data from this study thus can be used to provide compelling evidence for the wider implementation of the intervention model. Methods: In this randomized controlled trial, MSW were recruited and followed-up from May to December, 2021 in entertainment venues in Wuxi, Jiangsu Province, with an estimated sample size of 320. The MSW in the intervention group were provided with comprehensive interventions via key persons in entertainment venues compared with the control group receiving routine interventions. The effect of the intervention model was assessed by comparing the behavioral differences between these two groups and in the intervention group before and after intervention. Results: A total of 330 MSW were recruited at baseline survey, in which 168 were divided into intervention group and 162 into control group. There was no significant difference in socio-demographic characteristics between two groups (all P>0.05). After intervention for 6 months, the rate of consistent condom use in commercial homosexual activities in the intervention group was 79.5% (101/127), higher than 63.2% (74/117) in the control group, and in the intervention group, 90.1% (73/81) of MSW used condom consistently in heterosexual activities, higher than in the control group (59.6%, 59/99) . Compared with 30.8% (36/117) of MSW with drug abuse history in the control group, a lower proportion of 9.4% (12/127) was observed in the intervention group. Differences in all of aforementioned variables were significant (all P<0.05). After intervention, the incidence of group sex was 3.9% (5/127) in the intervention group and 9.4% (11/117) in the control group, the incidence of anal sex post-alcohol consumption was 40.2% (51/127) in the intervention group and 32.5% (38/117) in control group, the differences were not significant (all P>0.05). Conclusions: The intervention model based on key persons in entertainment venues could promote consistent condom use in MSW in both commercial homosexual and heterosexual activities and help them reduce drug abuse, but had no significant effect on decreasing group sex and anal sex after alcohol consumption. It is crucial to improve the intervention model according to the specific characteristics of MSW in order to enhance the effects of comprehensive intervention.

[Survey on the cognition of the "undetectable equals untransmittable" concept among HIV-infected men who have sex with men receiving antiviral treatment].

Objective: To explore the cognition of the "undetectable equals untransmittable" ("U=U") concept and associated factors among HIV-infected men who have sex with men (MSM) receiving antiviral treatment (ART) in Shenzhen, and provide evidence for designing promotion and advocacy strategies for the "U=U" concept. Methods: We recruited HIV-infected MSM receiving ART using convenient sampling method combined with routine follow-up in Shenzhen through conducting observational survey. The sample size was estimated to be 475. A questionnaire was administered to collect socio-demographic characteristics, sexual behaviors, ART, viral load testing and the cognition towards "U=U" in HIV-infected MSM. Logistic regression was used to access factors associated with acceptance of "U=U". Results: A total of 490 HIV-infected MSM receiving ART were recruited. Of whom, 60.2% (295/490) were aware of "U=U" and 50.6% (248/490) accepted "U=U". Multiple logistic regression showed that participants who had an educational level of college or above (aOR=1.76,95%CI: 1.12-2.75) were more likely to accept "U=U". Those who had no local residency (aOR=0.51,95%CI: 0.29-0.92), had viral load >0 copies/ml in the last testing (aOR=0.61,95%CI: 0.38-0.98) and were unaware of "U=U" (aOR=0.13, 95%CI: 0.09-0.21), were less likely to accept "U=U". Conclusions: HIV-infected MSM receiving ART had a low cognition level of "U=U" in Shenzhen. Promotion and advocacy on this concept through healthcare workers should be enhanced in combination with routine follow-up in order to improve their ART adherence and outcome of treatment. Furthermore, developing related guidelines on "U=U" according to the characteristics of HIV-infected individuals is warranted to improve the normalization of promotion and advocacy on "U=U".

Replacement of the replication factors of porcine circovirus (PCV) type 2 with those of PCV type 1 greatly enhances viral replication in vitro.

Porcine circovirus type 1 (PCV1), originally isolated as a contaminant of PK-15 cells, is nonpathogenic, whereas porcine circovirus type 2 (PCV2) causes an economically important disease in pigs. To determine the factors affecting virus replication, we constructed chimeric viruses by swapping open reading frame 1 (ORF1) (rep) or the origin of replication (Ori) between PCV1 and PCV2 and compared the replication efficiencies of the chimeric viruses in PK-15 cells. The results showed that the replication factors of PCV1 and PCV2 are fully exchangeable and, most importantly, that both the Ori and rep of PCV1 enhance the virus replication efficiencies of the chimeric viruses with the PCV2 backbone.

The emergence of genotypes 3 and 4 hepatitis E virus in swine and humans: a phylogenetic perspective.

To investigate whether there is any phylogenetic evidence to support the hypothesis that swine is the natural host of HEV genotypes 3 and 4, Bayesian analysis of 80 full-length genomic sequences of HEV was performed. The results showed that the strains of genotypes 3 and 4 from swine are paraphyletic with regard to strains of human origin, which are thus phylogenetically nested among the swine strains. Recognition of HEV genotypes 3 and 4 as viruses from swine or swine HEV can provide an evolutionary explanation to the observation of cross-species infection by genotypes 3 and 4 HEV.

Facile fabrication of hydrophobic cellulose-based organic/inorganic nanomaterial modified with POSS by plasma treatment.

A novel hydrophobic cellulose-based organic/inorganic nanomaterial (cellulose/TS-POSS) was prepared by oxygen plasma treatment followed by condensation reaction with TriSilanollsobutyl-Polyhedral oligomeric silsesquioxane. By careful design of cellulose film modified with TS-POSS by plasma etching, not only simply activated the hydroxyl groups on fiber surface, but also lowered the surface energy and increased the surface roughness. The surface morphology, chemical structure, thermal properties, and hydrophobic properties of cellulose/TS-POSS materials were systematically investigated by FTIR, SEM, AFM, CA, and TGA, respectively. The experimental results showed that the static water contact angle of cellulose/TS-POSS was 152.9°, demonstrating super-hydrophobicity. The results indicated that the TS-POSS were observed uniformly dispersed in the cellulose at the nanometer scale to form nanostructures, successful bonding to cellulose through condensation reaction. This process developed in this paper provided new solutions and approximations for the facile fabrication of sustainable cellulose-based hydrophobic materials.

Deletions of the hypervariable region (HVR) in open reading frame 1 of hepatitis E virus do not abolish virus infectivity: evidence for attenuation of HVR deletion mutants in vivo.

Hepatitis E virus (HEV) is an important human pathogen, although little is known about its biology and replication. Comparative sequence analysis revealed a hypervariable region (HVR) with extensive sequence variations in open reading frame 1 of HEV. To elucidate the role of the HVR in HEV replication, we first constructed two HVR deletion mutants, hHVRd1 and hHVRd2, with in-frame deletion of amino acids (aa) 711 to 777 and 747 to 761 in the HVR of a genotype 1 human HEV replicon. Evidence of HEV replication was detected in Huh7 cells transfected with RNA transcripts from mutant hHVRd2, as evidenced by expression of enhanced green fluorescent protein. To confirm the in vitro results, we constructed three avian HEV mutants with various HVR deletions: mutants aHVRd1, with deletion of aa 557 to 585 (Delta557-585); aHVRd2 (Delta612-641); and aHVRd3 (Delta557-641). Chickens intrahepatically inoculated with capped RNA transcripts from mutants aHVRd1 and aHVRd2 developed active viral infection, as evidenced by seroconversion, viremia, and fecal virus shedding, although mutant aHVRd3, with complete HVR deletion, was apparently attenuated in chickens. To further verify the results, we constructed four additional HVR deletion mutants using the genotype 3 swine HEV as the backbone. Mutants sHVRd2 (Delta722-781), sHVRd3 (Delta735-765), and sHVRd4 (Delta712-765) were shown to tolerate deletions and were infectious in pigs intrahepatically inoculated with capped RNA transcripts from the mutants, whereas mutant sHVRd1 (Delta712-790), with a nearly complete HVR deletion, exhibited an attenuation phenotype in infected pigs. The data from these studies indicate that deletions in HVR do not abolish HEV infectivity in vitro or in vivo, although evidence for attenuation was observed for HEV mutants with a larger or nearly complete HVR deletion.

Recent advances in Hepatitis E virus.

Hepatitis E virus (HEV), the causative agent of hepatitis E, belongs to the family Hepeviridae. At least four major genotypes of HEV have been recognized: genotypes 1 and 2 are restricted to humans and associated with epidemics in developing countries, whereas genotypes 3 and 4 are zoonotic and infect humans and several other animals in both developing and industrialized countries. Besides humans, strains of HEV have been genetically identified from swine, chickens, sika deer, mongeese, and rabbits. The genome of HEV consists of three open reading frames (ORFs): ORF1 codes for nonstructural proteins, ORF2 codes for capsid protein, and ORF3 codes for a small multifunctional protein. The ORF2 and ORF3 proteins are translated from a single bicistronic mRNA and overlap each other but neither overlaps ORF1. The recent determination of the 3D crystal structure of the HEV capsid protein should facilitate the development of vaccines and antivirals. The identification and characterization of animal strains of HEV from pigs and chickens and the demonstrated ability of cross-species infection by swine HEV raise public health concerns for zoonosis. Accumulating evidence indicated that hepatitis E is a zoonotic disease and pigs and more likely other animal species are reservoirs for HEV. This article provides an overview of the recent advances in hepatitis E and its causative agent, including nomenclature and genomic organization, gene expression and functions, 3D structure of the virions, changing perspectives on higher mortality during pregnancy and chronic hepatitis E, animal reservoirs, zoonotic risk, food safety, and novel animal models.