[Advance in occupational health risks and management of shift work].

The occupational health issues of shift workers has received increasing attention in the field of occupational health, and discussed in this article through literature review on the health risks and management of shift work both domestically and internationally. Based on this, a series of impacts of shift work on the physiological and psychological health of workers, as well as their family and social life, are revealed. Combined with relatively mature regulations and policies in foreign countries, it is proposed that China should fully learn from the relevant experience of health management in shift work abroad, Strengthen research and explore effective management intervention measures to provide ideas for accelerating the development of scientifically feasible regulations and policies related to occupational health in shift work in China.

[Analysis of the safety, accuracy, and factors influencing bleeding complications in CT-guided puncture biopsy of brain occupying lesions].

Objective: To investigate the safety and accuracy of CT-guided intracranial puncture biopsy and the possible influencing factors of postoperative bleeding complications. Methods: A case series study. A retrospective analysis was conducted on 101 patients who underwent CT-guided intracranial puncture biopsy at the First Affiliated Hospital of Zhengzhou University from January 2017 to December 2021. The basic data of patients and the safety and accuracy of CT-guided intracranial puncture biopsy were analyzed statistically. Univariate and multivariate logistic regression analysis were used to screen the influencing factors of bleeding complications in CT-guided intracranial puncture biopsy, and the bleeding complications in glioma subgroup were analyzed. Results: Among the 101 patients, 53 were males and 48 were females, aged (53.7±17.2) years. The average diameter of intracranial lesions was (3.5±1.4) cm, while the vertical distance from the lesion to the meninges was (2.4±1.7) cm. The needle's intracranial depth reached (3.2±1.8) cm, with adjustments averaging (3±1) occurrences and an average procedural duration of (40.2±12.9) minutes. Pathological diagnoses included glioma (36 cases), gliosis (3 cases), lymphoma (32 cases), metastatic tumors (7 cases), inflammatory lesions (13 cases), and 10 indeterminate cases. The positive rate of puncture pathology was 90.1% (91/101), and the diagnostic coincidence rate was 94.0% (78/83). The incidence of bleeding complications in CT-guided intracranial puncture biopsy was 26.7% (27/101), of which 23 cases had small intratoma or needle path bleeding, 4 cases had massive bleeding, and 2 cases died. The patients were divided into bleeding group (n=27) and no bleeding group (n=74), according to the presence or absence of bleeding. The results of univariate logistic regression analysis showed that thrombin time≥15 s and the number of needle adjustment were the factors affecting the occurrence of bleeding complications (both P<0.05), and the results of multivariate logistic regression showed that thrombin time≥15 s was the related factor for bleeding. Patients with thrombin time≥15 s had a 3.045 times higher risk of bleeding than those with thrombin time<15 s (OR=3.045,95%CI:1.189-7.799,P=0.020). Among the 101 patients, 36 cases of midbrain glioma were divided into low-grade glioma group (n=11) and high-grade glioma group (n=25) according to the pathological grade. Subgroup analysis showed that the risk of bleeding for high-grade gliomas was 9.231 times higher than that for low-grade gliomas (OR=9.231,95%CI:1.023-83.331,P=0.031). Conclusions: CT-guided intracranial puncture biopsy is safe and feasible with high accuracy. Complication rates are associated with thrombin time≥15 s, especially high-grade glioma, which increases the risk of postoperative bleeding.

[Efficacy analysis of hepatic arterial infusion chemotherapy combined with targeted and immune therapy followed by 125I seeds implantation in the treatment of hepatocellular carcinoma with portal vain tumor thrombus].

Objective: To investigate the safety and efficacy of Hepatic Arterial Infusion Chemotherapy(HAIC) combined with targeted and immune therapy followed by 125I seeds implantation in portal vain tumor thrombus (PVTT) in the treatment of hepatocellular carcinoma(HCC) with PVTT. Methods: A retrospective study was performed on the clinical data of 21 patients [ (11 men, 10 women) aged 34-73 (52.6±13.7) years] with HCC with PVTT in The First Affiliated Hospital of Zhengzhou University from October 2020 to October 2022, all of them were treated with HAIC plus targeted and immune therapy,and 125I seeds implanted into PVTT. The patients were followed up to January 2023, the efficacy was evaluated according to the modified version of the solid tumor efficacy evaluation criteria (mRECIST). The progression-free survival (PFS) rate, overall survival(OS) rate and portal tumor thrombus control rate at 3, 6, 12 and 18 months after treatment were recorded, and PFS and OS time were followed up. The changes of liver function, AFP, coagulation function and adverse events were observed. Results: Each patient received 2 to 7 (mean: 3.3±1.2) cycles of HAIC. 10-37 seeds (mean:16.6±6.7) were implanted per patients. The median follow-up time was 15 (range from 5 to 25) months.During the follow-up time, 15 patients showed progression and 6 patients died, and the PFS rates at 3, 6, 12, and 18 months after treatment were 90.5%, 71.4%, 42.9%, and 23.8%, respectively, and at 3, 6, 12, and 18-month OS rates were 100%, 100%, 81.0%, and 61.9%, respectively.The PVTT control rates at 3, 6, and 12 months were 90.5%, 90.5%, and 62.5%, respectively. Overall efficacy evaluation of CR rate 0, PR rate 47.6% (10/21), SD rate 38.1% (8/21), and PD rate 14.3% (3/21). The total incidence of treatment-related adverse events was 100%.Grade 3 treatment related adverse events were observed for 4 cases, the rest wereⅠtoⅡadverse events. Right upper abdominal pain, fever and hemorrhage in liver capsule related to the procedures were observed in 11(52.4%), 5(23.8%) and 3(14.3) patients, respectively. Conclusion: HAIC combined with targeted and immune therapy followed by 125I seeds implantation in PVTT is a safe and efficacy therapy for HCC with PVTT.

[Analysis of the safety and diagnostic efficiency of CT-guided percutaneous biopsy of pancreatic space-occupying lesions using large needle:comparison of trans-organ biopsy approach and non-trans-organ biopsy approach].

Objective: To compare the safety and diagnostic efficiency of CT-guided trans-organ and non-trans-organ large needle biopsy in the diagnosis of pancreatic space-occupying lesions. Methods: The clinical data of 367 patients with pancreatic mass who underwent CT-guided percutaneous biopsy in the First Affiliated Hospital of Zhengzhou University from January 2019 to January 2022 were retrospectively analyzed, including 211 males and 156 females, aged 18 to 87 (60.7±11.8) years old. They were divided into a trans-organ route group (n=142) and a non-trans-organ route group (n=225) according to whether traversing the organs during the procedures. The imaging data, pathological results, puncture process and complications of patients of the two groups were recorded. The successful rate for obtaining tissue,one-time successful diagnosis rate, accuracy, sensitivity, specificity, false negative rate and the incidence of complications were compared between the two groups. Results: There was no significant difference in baseline data between the two groups (all P>0.05).There were 28, 57, 24, and 33 biopsies were performed via a pathway traversing liver, stomach, small bowel and colon, respectively. The overall sampling success rates of the two groups were 100%.The one-time successful diagnosis rate did not show statistically difference between the two groups [86.6%(123/142) vs 87.1%(196/225),P=0.892]. There was no statistically difference in accuracy, sensitivity and false negative rates between trans-organ route group and non-trans-organ routegroup [92.3%(131/142) vs 92.0%(207/225), 91.8% (123/134) vs 90.0%(190/211) and 8.2% (11/134) vs 10.0%(21/211), all P>0.05]. The specificity was 100% in both groups. The common complications of the two groups were increased pancreatic amylase and hematoma, and there was no significant difference in the incidence of complications between the trans-organ route group and the non-trans-organ route group [10.6% (15/142) vs 12.4% (28/225), P=0.585]. In the trans-organ route group, 5 patients had increased pancreatic amylase and 10 patients had local hematoma, all of which were improved after conservative treatment. In the non-organ route group, 11 patients had elevated pancreatic amylase, and 17 patients had local hematoma, 1 case received surgical treatment due to bleeding, the rest were improved by conservative treatment. Conclusion: CT-guided percutaneous transabdominal organ large needle biopsy of pancreatic space-occupying lesions has the comparable diagnostic efficiency and safety as non-transabdominal organ approach.

[Correlation between HIV infection, club drug use and anal canal human papillomavirus infection in men who have sex with men in Taizhou].

Objective: To explore the correlation between club drug use and anal canal human papillomavirus (HPV) infection in HIV-negative and HIV-positive men who have sex with men (MSM) in Taizhou. Methods: A cross-sectional survey was conducted in Taizhou. HIV-negative MSM were recruited by convenient sampling in voluntary counseling and testing clinics of Taizhou prefectural CDC from August 2016 to October 2017, and HIV-positive MSM were recruited through the routine follow-up and management by Taizhou prefectural CDC from August 2016 to June 2019. A face-to-face questionnaire interview was conducted to collect the information about the socio-demographic characteristics, sexual orientation, sexual behavior, club drug use and other information of the participants. Anal canal swabs were collected for HPV genotyping. The correlation between club drug use and the prevalence of HPV infection were evaluated with χ2 test and logistic regression analysis. Results: A total of 69 HIV-negative and 345 HIV-infected MSM were included. The prevalence of any type of anal canal HPV infection in HIV-negative MSM (27.5%, 19/69) was lower than that in HIV-positive MSM (66.4%, 229/345) (χ2=36.114,P<0.001). The prevalence of self-reported club drug use in HIV-negative MSM was higher (17.4%, 12/69) than that in HIV-positive MSM (7.0%, 24/345) (χ2=7.886, P=0.005). For HIV-negative MSM, the prevalence of club drug use was higher in MSM who had homosexual group sex (P=0.036); the prevalence of HPV infection was 50.0% (6/12) in club drug users and 22.8% (13/57) in non-club drug users (χ2=3.674, P=0.055). For HIV-positive MSM, the prevalence of HPV infection was 70.8% (17/24) in club drug users and 66.0% (212/321) in non-club drug users (χ2=0.230, P=0.632). Multivariable logistic regression model showed that HPV infection in MSM was positively correlated with HIV infection (OR=5.42, 95%CI: 2.92-10.06), and the association between HPV infection and club drug use (OR=1.66, 95%CI: 0.75-3.71) was not significant. Conclusions: HIV infection was positively correlated with anal canal HPV infection in MSM in Taizhou. Club drug use was positively correlated with high-risk sexual behaviors, while its association with HPV infection needs further study.

[HIV-1 drug resistance and subtypes in newly reported HIV/AIDS patients before antiretroviral therapy in Taizhou city, 2016-2018].

Objective: To explore the HIV-1 drug resistance and subtypes in newly reported HIV/AIDS patients before antiretroviral therapy (ART) in Taizhou city. Methods: A cross-sectional study of HIV-1 drug resistance was conducted among newly reported HIV/AIDS patients before ART in Taizhou from January 2016 to December 2018. HIV-1 pol gene sequences were obtained by RT-PCR. The sequences were submitted to the Stanford University drug resistance database. The drug resistance mutation and the sensitivity of HIV-1 strains to antiretroviral drugs were determined according to WHO Guidelines on HIV drug resistance surveillance of 2014. Results: A total of 806 HIV-1 pol gene sequences were obtained successfully. The overall HIV-1 drug resistance rate was 2.9% (23/806), 1.9% for non-nucleoside reverse transcriptase inhibitors (NNRTIs), 0.6% for nucleoside reverse transcriptase inhibitors (NRTIs), and 0.0% for protease inhibitors (PIs), respectively. From 2016 to 2018, the HIV-1 drug resistance rate was 1.6%, 1.8%, and 4.8%, respectively. The resistance mutations of NNRTIs and NRTIs were mainly K103 N (0.7%) and M184I/V (0.5%). HIV-1 subtypes were mostly CRF01_AE (42.7%,344/806),CRF07_BC (28.9%,233/806) and CRF08_BC (11.2%,90/806).HIV-1 subtypes among homosexually transmitted infections were mostly CRF01_AE (53.3%, 136/255) and CRF07_BC (32.2%, 82/255), and HIV-1 subtypes among heterosexually transmitted infections were mainly CRF01_AE (37.7%, 203/539), CRF07_BC (27.5%, 148/539) and CRF08_BC (16.1%, 87/539). Conclusion: HIV-1 drug resistance rate among newly reported HIV/AIDS patients before ART remained low in Taizhou during 2016 to 2018, an increasing trend seemed to be notifiable and warrants continuous surveillance of HIV-1 drug resistance.

[Effects of copper and cadmium ions on protective enzyme activity in Oncomelania hupensis].

OBJECTIVE: To evaluate the effects of Cu2+ and Cd2+ at different concentrations on superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity in Oncomelania hupensis. METHODS: Cu2+- and Cd2+-containing solutions were prepared at 7 concentrations, and O. hupensis snails were exposed to the solutions for 24 h, of 15 snails in each concentration. Then, the snail body was collected following removal of the snail shell and homogenated, and the SOD, CAT and POS activities were detected in the supernatants. RESULTS: With the increase of the Cu2+ concentration, the SOD activity appeared a rise followed by a reduction in O. hupensis snails, and the CTA activity appeared a decline-rise-decline tendency, while the POD activity showed a tendency towards rise followed by decline. With the increase of the Cd2+ concentration, the SOD activity appeared a rise followed by a reduction in O. hupensis snails, and the CTA activity appeared a decline- rise- decline tendency, while the POD activity showed a decline-rise-decline tendency. CONCLUSIONS: Exposure to Cu2+ and Cd2+ at high concentrations results in a decline in the activity of SOD, CAT and POD in O. hupensis at the same time.

[Acute toxicity of four heavy metal ions to Oncomelania hupensis].

OBJECTIVE: To assess the acute toxicity of Cu2+, Cd2+, Hg2+ and Pb2+ to Oncomelania hupensis. METHODS: Cu2+, Cd2+, Hg2+ and Pb2+ solutions were prepared at five concentrations, and 10 snails were exposed to each concentration for 24, 48, 72 h and 96 h. Then, the inhibition of snail activity and snail death was observed, and the half maximal effective concentration (EC50) and median lethal concentrations (LC50) were estimated. RESULTS: The 24, 48, 72 h and 96 h EC50 values of Cu2+, Cd2+, Hg2+ and Pb2+ were 0.74, 0.56, 0.46, 0.37 mg/L, 4.79, 3.52, 1.70, 1.26 mg/L, 1.90, 1.49, 0.83, 0.76 mg/L and 21.40, 9.98, 7.90, 5.42 mg/L for snails, respectively. The 96 h LC50 values of Cu2+, Cd2+, Hg2+ and Pb2+ were 0.43, 2.96, 1.12 mg/L and 12.22 mg/L for snails, the safe concentrations were 0.004 3, 0.029 6, 0.011 2, 0.122 2 mg/L, respectively. CONCLUSIONS: Cu2+ shows a high acute toxicity to snails, and Cd2+ and Hg2+ exhibit a moderate acute toxicity to snails, while Pb2+ is lowly toxic to snails.

Nitrate-induced and in situ electrochemical activation synthesis of oxygen deficiencies-rich nickel/nickel (oxy)hydroxide hybrid films for enhanced electrocatalytic water splitting.

Hydrogen produced by electrochemical water splitting offers a hopeful and renewable solution for addressing the global energy crisis; however, development of highly efficient non-noble-metal electrocatalysts remains a big challenge. Herein, we report a facile strategy to fabricate oxygen deficiencies-rich nickel/nickel (oxy)hydroxide hybrid films as efficient electrocatalysts for water splitting by in situ oxygen evolution reaction (OER) activation. Under OER conditions, the originally deposited Ni films from the ethaline-based deep eutectic solvent (DES) undergo a structural rearrangement with a phase transformation in the oxidation state from Ni(ii) to Ni(iii) at the surface. The change is coupled with an increase in oxygen deficiencies and a pronounced defective precursor is induced by the addition of nitrate ions, providing structural disordering and boosting the intrinsic activity of the catalyst, which strongly enhances the water splitting performance.

Bacillus amyloliquefaciens CotA degradation of the lignin model compound guaiacylglycerol-ß-guaiacyl ether.

The cotA gene from Bacillus amyloliquefaciens MN-13 was cloned and expressed in Escherichia coli Transetta. Nucleotide sequence analysis showed an open reading frame of 1542 bp encoding a polypeptide comprised of 513 amino acids. The degradation of lignin model compounds by recombinant CotA was investigated by HPLC-MS with guaiacylglycerol-ß-guaiacyl ether as the substrate. The compounds including guaiacol, 3-(4-hydro-3-methoxyphenyl)-3-oxo-propanol and 4-hydro-3-methoxy acetophenone detected by HPLC-MS verified the rupture of ß-O-4 bond and oxidation Cα bond of guaiacylglycerol-ß-guaiacyl ether by CotA. 4-vinylguaiacol and 1-(4-hydroxy-3-methoxyl phenyl)-1-(2-methoxyl) phenoxyl ethylene were first time found in the degradation products of guaiacylglycerol-ß-guaiacyl ether. The appearance of 4-vinylguaiacol and 4-hydro-3-methoxy acetophenone confirmed the cleavage of Cß-Cγ bond. 1-(4-hydroxy-3-methoxyl phenyl)-2-(2-methoxyl) phenoxyl ethylene was coupled by the radical reaction of 4-vinylguaiacol with guaiacol. Otherwise, no corresponding degradation product was found to give a proof of cleavage of Cα-Cß bond in guaiacylglycerol-ß-guaiacyl ether by CotA.

Microstructural visual pathway abnormalities in patients with primary glaucoma: 3 T diffusion kurtosis imaging study.

AIM: To evaluate microstructural visual pathway damage in patients with primary glaucoma (PG) by using 3 T diffusion kurtosis imaging (DKI). MATERIALS AND METHODS: The study was approved by the ethics committee, and all participants provided written informed consent. Ten patients with PG were examined. Twenty healthy individuals served as control subjects. DKI was performed with a GE Silent 3 T magnetic resonance imaging (MRI) unit. Mean diffusivity (MD), fractional anisotropy (FA), and mean kurtosis (MK) maps were automatically created. Mean MK, MD, and FA values were calculated for each part of the visual pathway. RESULTS: No abnormalities in the shape and signal intensity were observed along the entire visual pathway in patients and the control group on the conventional MRI. Higher MD, and lower MK and FA were observed in the optic nerves (ON), lateral geniculate nucleus (LGN), optic radiations (OR), and visual cortex (VCx) of PG patients, as compared with control subjects. A significantly higher MD was observed in the ON (p<0.01), and significantly lower FA was observed in OR (p<0.05). Additionally, significantly lower MK was observed in the ON, LGN, and VCx, except for OR (p<0.01). Changes of DKI parameters in the ON were the most distinct. CONCLUSION: Glaucoma is a complex neurological disease that affects the entire visual pathway. MK derived from DKI would be a better biomarkers than FA and MD in detecting microstructural damage.

Identification of genes related to floral organ development in pak choi by expression profiling.

Pak choi is a highly nutritious vegetable that is widely grown in China, Southeast Asia, and other parts of the world. Because it reproduces by seed, it is very important to understand the mechanism of floral organ development. Therefore, using the Chinese cabbage genome as a reference, this study analyzed the expression profiles of shoot apex genes at flower bud differentiation stages 1 and 5, in order to identify genes related to floral organ development. The results showed that the proportion of mapped genes was high, with 84.25 and 83.80% of clean reads from the two sample saligned to the reference genome, respectively. A total of 525 differentially expressed genes (DEGs) were identified, 224 of which were upregulated and 301 were downregulated. The expression levels of genes homologous to Chinese cabbage flowering genes were also analyzed at stages 1 and 5; the expression levels of Bra012997 (ap1), Bra000393 (SOC1), and Bra004928 (SOC1) were significantly upregulated at stage 5, suggesting that these three genes positively regulate floral development in pak choi. DEGs involved in floral organ development were analyzed with homologous genes from Arabidopsis thaliana; the homologous genes Bra029281 (AGL42), Bra026577 (ARPN), Bra022954 (SPL3), Bra029293 (ARF2), Bra007978 (AtRLP12), Bra033221 (SPL8), Bra008037 (LOX4), Bra001598 (IAA19), Bra003892 (PATL1), Bra038778 (AT4G21323), Bra025315 (KLCR2), and Bra013906 (DTX35) are directly related to floral organ development in Arabidopsis, suggesting that these genes have corresponding functions during flower organ development in pak choi, and could be candidates for further genetic research. These results provide a foundation for research on the molecular mechanism of flower organ development in pak choi and other Brassica rapa vegetables.

MYBA2 gene involved in anthocyanin and flavonol biosynthesis pathways in grapevine.

MYBA2 transcription factor (Myb-related gene) affects the coloring in grapevine berry and plays an important role in the biosynthesis of anthocyanin. The MYBA2 gene was cloned from Vitis vinifera L. cv. Cabernet Sauvignon and polyclonal antibodies for VvmybA2 were prepared. The VvmybA2 gene expression patterns were observed in seven tissues (the leaf, stem, flower, bud, root, berry, and tendril) and during the berry development stage at transcriptional and translational levels, respectively. The results indicated that the expression of VvmybA2 was approximately 11-fold higher in the berry than that in the other six tissues, and increased rapidly from 60 days after full bloom reaching a maximum on day 80. Furthermore, both the anthocyanin content and UDP-glucose:flavonoid-3-O-glucosyltransferase (UFGT) gene expression levels increased rapidly 60 days after full bloom. Moreover, correlation analysis indicated that the transcriptional and translational expression levels of the VvmybA2 gene were significantly positively correlated with not only UFGT and DFR genes but also with the anthocyanin content during berry development. These results suggested that VvmybA2 could not only regulate the transcription of both UFGT and DFR but also is involved in the expression of the UFGT gene associated with color determination in grape berries.

Accumulation of flavanols and expression of leucoanthocyanidin reductase induced by postharvest UV-C irradiation in grape berry.

To examine the effect of postharvest ultraviolet C (UV-C) irradiation on flavanol polyphenol accumulation in the grape berry, we investigated total flavanol polyphenol content, the enzyme activity of leucoanthocyanidin reductase (LAR), and transcription of Vv lar1 and Vv lar2 using spectrophotometry, real-time polymerase chain reaction, and western blot analysis in 5-year-old Vitis vinifera L. cv. Cabernet Sauvignon plants. Our results indicated that the accumulation of flavanol polyphenol reached its highest value when exposed to UV-C irradiation for 30 min. Additionally, UV-C irradiation induced the transcription of Vv lar1 and Vv lar2 and the synthesis of LAR1 and LAR2 proteins, resulting in increased accumulation of flavanol polyphenol in the grape berry. Moreover, these effects were associated with the length of time of UV-C irradiation.

Symbiosis of Mycoplasma hominis in Trichomonas vaginalis may link metronidazole resistance in vitro.

Fourteen of 28 Trichomonas vaginalis isolates collected from patients in Guangzhou, China from 2003 to 2004 were found to be naturally infected with Mycoplasma hominis, as determined by PCR using specific primers. In vitro metronidazole sensitivity assay of the 28 isolates revealed four displaying low susceptibility [minimum lethal concentration (MLC)= approximately 13-25 microg/ml] and another four displaying high resistance (MLC=50-100 microg/ml). The overwhelming majority of these resistant isolates (7/8) were mycoplasma-infected. The mean of MLCs of mycoplasma-infected isolates is approximately 10-fold higher than the mean of noninfected isolates (p=0.029). Sequence analyses of PCR-amplified small subunit-large subunit rRNA interspacer regions (ITS1/5.8S/ITS2) revealed that 23 of the 28 samples are identical, the remaining five being separable into two groups, each with a single point mutation. These internal transcribed spacer sequence variants are associated neither with mycoplasma infection nor with drug resistance. In contrast, random amplified polymorphic DNA analyses of DNAs using 10 different primers showed that the drug-resistant isolates are clustered together in association with mycoplasma infection, albeit more loosely. Taken together, the results obtained from this study suggest that in vitro metronidazole resistance of T. vaginalis is related to mycoplasma infection of this protozoan.

Three genes encoding for putative methyl- and acetyltransferases map adjacent to the wzm and wzt genes and are essential for O-antigen biosynthesis in Rhizobium etli CE3.

The elucidation of the structure of the O-antigen of Rhizobium etli CE3 predicts that the R. etli CE3 genome must contain genes encoding acetyl- and methyltransferases to confer the corresponding modifications to the O-antigen. We identified three open reading frames (ORFs) upstream of wzm, encoding the membrane component of the O-antigen transporter and located in the lps alpha-region of R. etli CE3. The ORFs encode two putative acetyltransferases with similarity to the CysE-LacA-LpxA-NodL family of acetyltransferases and one putative methyltransferase with sequence motifs common to a wide range of S-adenosyl-L-methionine-dependent methyltransferases. Mutational analysis of the ORFs encoding the putative acetyltransferases and methyltransferase revealed that the acetyl and methyl decorations mediated by these specific enzymes are essential for O-antigen synthesis. Composition analysis and high performance anion exchange chromatography analysis of the lipopolysaccharides (LPSs) of the mutants show that all of these LPSs contain an intact core region and lack the O-antigen polysaccharide. The possible role of these transferases in the decoration of the O-antigen of R. etli is discussed.

Employment and contextual impact of safe and unsafe sexual practices for STI and HIV: the situation in China.

China's dual employment system plays a crucial role in sexually transmitted infections (STIs) and HIV-related safe and unsafe sexual practices among young Chinese people. Social and psychological determinants of safe and unsafe sexual practices for HIV infection among young people in Sichuan, China were examined. Our findings indicate that changes in China's social structure and employment system impact upon the social contextual involvement and socio-sexual practice of young Chinese people. The findings in the study suggest that the employment-related contextual involvement was a major predictor in the relationships between demography, information, and psychological risk-taking factors on one hand and the people's safe and unsafe sexual practices on the other. Self-employed people (officially called 'getihu') were more likely than the state-employed people to engage in unprotected sex with casual sexual partners. As China undergoes social restructuring and many state-employed people are laid off, the risk may also extend into the broader non-self-employed population as more state-employed people become involved not only in the self-employed getihu's socioeconomic activities but also in their unconventional socio-sexual practices. Collective vulnerability to STI and HIV, due to the current socio-sexual practices of the getihu young people, has created a new frontier for STI and HIV prevention in today's China, as well as demonstrating the importance of collective action with STI and AIDS prevention strategies within relevant social and sub-cultural contexts.

Synthesis of novel 3'-C-methyl-apionucleosides: an asymmetric construction of a quaternary carbon by Claisen rearrangement.

The synthesis of 2,3-dideoxy-3-C-(hydroxymethyl)-3-C-methyl-D-glycero-tetrofuranosyl++ + nucleosides was accomplished in high enatiomeric purity (98.5% ee) via [3,3]-sigmatropic Claisen rearrangement of (E)(S)-5-benzyloxy-1-tert-butyldimethylsilanyloxy-4-methyl-pent-3- en-2-ol prepared from 2,3-O-isopropylidene-D-glyceraldehyde. The synthesized nucleosides were assayed against human immunodeficiency virus (HIV) and hepatitis B virus in human peripheral blood mononuclear (PBM) and 2.2.15 cells, respectively. 6-Amino-9-[2,3-dideoxy-3-C-(hydroxymethyl)-3-C-methyl-beta-D-glycero- tetrofuranosyl]-2-fluoropurine shows moderate antiviral activity (EC50 = 2.55 microM) against HIV-1 strains and 6-amino-9-[3-deoxy-3-C-(hydroxymethyl)-3-methyl-alpha-D-glycero-tetro furanosyl]-2-fluoropurine exhibits potent anti-HIV activity (EC50 = 0.073 microM) with significant cytotoxicity (IC50 = 1.0 microM).