Multifractal Characteristics Analysis of Spatial State of Prefecture-Level Cities in China.

In the last 40 years, Chinese cities have seen extensive development across a wide array of spheres. In this study, we applied a power-law and multifractal analysis to characterise 22 indices for 288 prefecture-level cities in mainland China. The data used to characterise the indices is representative of the year 2012. The results show that the Gross domestic product (GDP) is regular and exhibits multifractal spatial characteristics. Specifically, most developmental fields exhibit coupling in conjunction with being chaotic. Furthermore, eight indices with multifractal characteristics clearly reflect the spatial complexity of the corresponding fields and the volatility between prefecture-level cities. Overall, the tertiary industry has undergone nongeneralised development. On the other hand, the construction industry resembles a bubble economy, and the spatial layout of traditional industries has a homogenising effect in Middle and East China. This study examines China's overall spatial characteristics and states based on the above-mentioned analyses; additionally, the study focuses on the early 2010s. The contribution of this study provides a quantitative analysis paradigm based on a multifractal approach.

Transarterial chemoembolization plus a PD-1 inhibitor with or without lenvatinib for intermediate-stage hepatocellular carcinoma.

AIM: Transarterial chemoembolization (TACE) combined with a PD-1 inhibitor and TACE combined with a PD-1 inhibitor and lenvatinib have recently been reported as promising treatments to improve the prognosis of hepatocellular carcinoma (HCC) patients. This study aims to compare the efficacy of these two treatments. METHODS: A retrospective study was conducted, and patients were recruited from two centers in China. Progression-free survival (PFS) and overall survival (OS) were compared, and the objective response rate (ORR) and disease control rate (DCR) were evaluated according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST). Treatment-related adverse events (AEs) were analyzed to assess safety. RESULTS: The median follow-up for the entire cohort was 11.4 months. Of the 103 patients included in this study, 56 received triple therapy, and 47 received doublet therapy. PFS was significantly higher in the triple therapy group than in the doublet therapy group (mPFS 22.5 vs. 14.0 months, P < 0.001). Similar results were obtained in terms of OS (P = 0.001). The ORR and DCR were also better in the triple therapy group (64.3% vs. 38.3%, P = 0.010; 85.7% vs. 57.4%, P = 0.002). The most common AEs in the triple therapy group were decreased albumin (55.3%), decreased platelet count (51.8%) and hypertension (44.6%). CONCLUSIONS: The combination of TACE with a PD-1 inhibitor and lenvatinib in patients with BCLC stage B HCC might result in significantly improved clinical outcomes with a manageable safety profile compared with TACE with a PD-1 inhibitor.

SARS-CoV-2 Spike N-Terminal Domain modulates TMPRSS2-dependent viral entry and fusogenicity

Over 20 mutations have been identified in the N-Terminal Domain (NTD) of SARS-CoV-2 spike and yet few of them are fully characterised. Here we first examined the contribution of the NTD to infection and cell-cell fusion by constructing different VOC-based chimeric spikes bearing B.1617 lineage (Delta and Kappa variants) NTDs and generating spike pseudotyped lentivirus (PV). We found the Delta NTD on a Kappa or WT background increased spike S1/S2 cleavage efficiency and virus entry, specifically in Calu-3 lung cells and airway organoids, through use of TMPRSS2. We have previously shown Delta spike confers rapid cell-cell fusion kinetics; here we show that increased fusogenicity can be conferred to WT and Kappa variant spikes by transfer of the Delta NTD. Moving to contemporary variants, we found that BA.2 had higher entry efficiency in a range of cell types as compared to BA.1. BA.2 showed higher fusogenic activity than BA.1, but the BA.2 NTD could not confer higher fusion to BA.1 spike. There was low efficiency of TMPRSS2 usage by both BA.1 and BA.2, and chimeras of Omicron BA.1 and BA.2 spikes with a Delta NTD did not result in more efficient use of TMRPSS2 or cell-cell fusogenicity. We conclude that the NTD allosterically modulates S1/S2 cleavage and spike-mediated functions such as entry and cell-cell fusion in a spike context dependent manner, and allosteric interactions may be lost when combining regions from more distantly related spike proteins. These data may explain the lack of successful SARS-CoV-2 inter-variant recombinants bearing breakpoints within spike.

Preparation of asymmetric particles by controlling the phase separation of seeded emulsion polymerization with ethanol/water mixture.

Alcohols are discovered for the first time to tune the morphology of poly(vinyl benzyl chloride)-poly(3-methacryloxypropyltrimethoxysilane) (PVBC-PMPS) composite particles through seeded emulsion polymerization within the alcohol/water mixture. Here, monodispersed linear PVBC particles was synthesized through the dispersion polymerization and employed as the seeds. The as-obtained PVBC-PMPS composite particles could be dramatically tuned from core-shell structures to snowman-like particles, to dumbbell-shaped particles, to inverse snowman-like particles when the ethanol content in reaction mixtures is only adjusted within a narrow range. The morphology of fresh PMPS bulges was observed after removing the linear PVBC seeds with N,N'-dimethyl formamide, and their formation mechanism was studied by monitoring the free radical polymerization and sol-gel process of 3-methacryloxypropyltrimethoxysilane. It has been confirmed that the sol-gel kinetics were the main factor on the particles' morphology. In addition, morphologies of PVBC-PMPS particles were also varied by the MPS feeding amount, types of the co-solvent and pH values of alcohol/water mixtures.

Global characterization of modifications to the charge isomers of IgG antibody / 药物分析学报

Posttranslational modifications of antibody products affect their stability,charge distribution,and drug activity and are thus a critical quality attribute.The comprehensive mapping of antibody modifications and different charge isomers(CIs)is of utmost importance,but is challenging.We intended to quanti-tatively characterize the posttranslational modification status of CIs of antibody drugs and explore the impact of posttranslational modifications on charge heterogeneity.The CIs of antibodies were fraction-ated by strong cation exchange chromatography and verified by capillary isoelectric focusing-whole column imaging detection,followed by stepwise structural characterization at three levels.First,the differences between CIs were explored at the intact protein level using a top-down mass spectrometry approach;this showed differences in glycoforms and deamidation status.Second,at the peptide level,common modifications of oxidation,deamidation,and glycosylation were identified.Peptide mapping showed nonuniform deamidation and glycoform distribution among CIs.In total,10 N-glycoforms were detected by peptide mapping.Finally,an in-depth analysis of glycan variants of CIs was performed through the detection of enriched glycopeptides.Qualitative and quantitative analyses demonstrated the dynamics of 24 N-glycoforms.The results revealed that sialic acid modification is a critical factor ac-counting for charge heterogeneity,which is otherwise missed in peptide mapping and intact molecular weight analyses.This study demonstrated the importance of the comprehensive analyses of antibody CIs and provides a reference method for the quality control of biopharmaceutical analysis.

Effect of atorvastatin combined with alendronate in the treatment of T2DM with osteoporosis on bone metabolism, TNF-α, IL-6, and 25- (OH) D levels / 中华内分泌外科杂志

Objective:To investigate the effects of atorvastatin combined with alendronate in the treatment of type 2 diabetes mellitus (T2DM) with osteoporosis (OP) on bone metabolism, tumor necrosis factor alpha (TNF-α) , interleukin 6 (IL-6) , and 25-hydroxyvitamin D[25- (OH) D] level.Methods:A total of 152 patients with T2DM and OP who were diagnosed and treated in our hospital from Jul. 2017 to Jul. 2020 were selected. According to the different treatment methods, they were divided into control group (73 cases with alendronate treatment) and study group (79 cases receiving atova Statins combined with alendronate sodium treatment) . The two groups were compared in terms of bone metabolism indexes, bone mineral density, changes in serum TNF-α, IL-6, 25- (OH) D levels, and adverse reactions before and after treatment.Results:After treatment, osteocalcin (BGP) , bone-specific alkaline phosphatase (BAP) , lumbar spine L1-4 bone mineral density, femoral neck bone mineral density, and 25- (OH) D of the two groups increased ( P< 0.001) , and the study group was significantly higher than the control group (BGP: 7.68±0.89 vs 6.88±0.93; BAP: 18.62±3.97 vs 16.82±3.24; lumbar spine L1-4: 0.95±0.08 vs 0.92±0.05; femoral neck: 0.79±0.07 vs 0.75±0.06; 25- (OH) D: 31.35±10.1 vs 26.54±7.14; all P<0.05) . After treatment, the serum type I collagen C-terminal peptide (s-CTX) , human tartrate acid phosphatase (TRAP-5b) , TNF-α, IL-6 were decreased for both groups ( P<0.001) , and they were significantly lower in the study group than those in the control group (s-CTX:0.37±0.12 vs 0.55±0.12; TRAP-5b: 2.43±0.66 vs 2.99±0.75; TNF-α: 9.93±1.91 vs 11.77±2.69; IL-6: 10.65±1.26 vs 12.91±1.21; all P<0.001) . The incidence of adverse reactions in the study group was significantly lower than that in the control group (16.46% vs 39.73%, P=0.001) . Conclusion:Atorvastatin combined with alendronate in the treatment of T2DM patients with OP can effectively increase 25- (OH) D levels, reduce inflammation, and promote bone metabolism and bone density.

Research progress in biological characteristics and influencing factors of jaw bone marrow mesenchymal stem cell / 中华口腔医学杂志

Jaw bone marrow mesenchymal stem cell (JBMMSC), which exists in the maxilla and mandible, is adult stem cells with strong proliferation ability and multiple differentiation potential. Pathological, physicochemical and biological factors can affect the biological characteristics of JBMMSC. Compared with bone marrow mesenchymal stem cells derived from long bone, the biological characteristics of JBMMSC are site-specific because of the different sources of tissue and osteogenesis of bone. The same influencing factors have different effects on these two kinds of cells. Besides, JBMMSC also has the advantages of easier access, less trauma and lower immunogenicity. It has broad application prospects in craniomaxillofacial defect repair, periodontal tissue regeneration, and improving the success rate after implantation and so on. It has attracted wide attention in the basic and clinical studies. However, the regulation mechanism of its proliferation and differentiation is not clear, which affects its application as seed cell. Therefore, this paper reviews the biological characteristics influencing factors of JBMMSC and application progress in clinical and basic research, aiming to provide reference for further research and clinical application.

SARS-CoV-2 Omicron spike mediated immune escape, infectivity and cell-cell fusion

The SARS-CoV-2 Omicron BA.1 variant emerged in late 2021 and is characterised by multiple spike mutations across all spike domains. Here we show that Omicron BA.1 has higher affinity for ACE2 compared to Delta, and confers very significant evasion of therapeutic monoclonal and vaccine-elicited polyclonal neutralising antibodies after two doses. mRNA vaccination as a third vaccine dose rescues and broadens neutralisation. Importantly, antiviral drugs remdesevir and molnupiravir retain efficacy against Omicron BA.1. We found that in human nasal epithelial 3D cultures replication was similar for both Omicron and Delta. However, in lower airway organoids, Calu-3 lung cells and gut adenocarcinoma cell lines live Omicron virus demonstrated significantly lower replication in comparison to Delta. We noted that despite presence of mutations predicted to favour spike S1/S2 cleavage, the spike protein is less efficiently cleaved in live Omicron virions compared to Delta virions. We mapped the replication differences between the variants to entry efficiency using spike pseudotyped virus (PV) entry assays. The defect for Omicron PV in specific cell types correlated with higher cellular RNA expression of TMPRSS2, and accordingly knock down of TMPRSS2 impacted Delta entry to a greater extent as compared to Omicron. Furthermore, drug inhibitors targeting specific entry pathways demonstrated that the Omicron spike inefficiently utilises the cellular protease TMPRSS2 that mediates cell entry via plasma membrane fusion. Instead, we demonstrate that Omicron spike has greater dependency on cell entry via the endocytic pathway requiring the activity of endosomal cathepsins to cleave spike. Consistent with suboptimal S1/S2 cleavage and inability to utilise TMPRSS2, syncytium formation by the Omicron spike was dramatically impaired compared to the Delta spike. Overall, Omicron appears to have gained significant evasion from neutralising antibodies whilst maintaining sensitivity to antiviral drugs targeting the polymerase. Omicron has shifted cellular tropism away from TMPRSS2 expressing cells that are enriched in cells found in the lower respiratory and GI tracts, with implications for altered pathogenesis.

SARS-CoV-2 B.1.617 emergence and sensitivity to vaccine-elicited antibodies

The SARS-CoV-2 B.1.617.2 (Delta) variant was first identified in the state of Maharashtra in late 2020 and spread throughout India, outcompeting pre-existing lineages including B.1.617.1 (Kappa) and B.1.1.7 (Alpha). In vitro, B.1.617.2 is 6-fold less sensitive to serum neutralising antibodies from recovered individuals, and 8-fold less sensitive to vaccine-elicited antibodies as compared to wild type Wuhan-1 bearing D614G. Serum neutralising titres against B.1.617.2 were lower in ChAdOx-1 versus BNT162b2 vaccinees. B.1.617.2 spike pseudotyped viruses exhibited compromised sensitivity to monoclonal antibodies against the receptor binding domain (RBD) and N-terminal domain (NTD), in particular to the clinically approved bamlavinimab and imdevimab monoclonal antibodies. B.1.617.2 demonstrated higher replication efficiency in both airway organoid and human airway epithelial systems as compared to B.1.1.7, associated with B.1.617.2 spike being in a predominantly cleaved state compared to B.1.1.7. Additionally we observed that B.1.617.2 had higher replication and spike mediated entry as compared to B.1.617.1, potentially explaining B.1.617.2 dominance. In an analysis of over 130 SARS-CoV-2 infected healthcare workers across three centres in India during a period of mixed lineage circulation, we observed substantially reduced ChAdOx-1 vaccine efficacy against B.1.617.2 relative to non-B.1.617.2. Compromised vaccine efficacy against the highly fit and immune evasive B.1.617.2 Delta variant warrants continued infection control measures in the post-vaccination era.

Age-related heterogeneity in Neutralising antibody responses to SARS-CoV-2 following BNT162b2 vaccination

Two dose mRNA vaccination provides excellent protection against SARS-CoV-2. However, there are few data on vaccine efficacy in elderly individuals above the age of 801. Additionally, new variants of concern (VOC) with reduced sensitivity to neutralising antibodies have raised fears for vulnerable groups. Here we assessed humoral and cellular immune responses following vaccination with mRNA vaccine BNT162b22 in elderly participants prospectively recruited from the community and younger health care workers. Median age was 72 years and 51% were females amongst 140 participants. Neutralising antibody responses after the first vaccine dose diminished with increasing age, with a marked drop in participants over 80 years old. Sera from participants below and above 80 showed significantly lower neutralisation potency against B.1.1.7, B.1.351 and P.1. variants of concern as compared to wild type. Those over 80 were more likely to lack any neutralisation against VOC compared to younger participants following first dose. The adjusted odds ratio for inadequate neutralisation activity against the B.1.1.7, P.1 and B.1.351 variant in the older versus younger age group was 4.3 (95% CI 2.0-9.3, p<0.001), 6.7 (95% CI 1.7-26.3, p=0.008) and 1.7 (95% CI 0.5-5.7, p=0.41). Binding IgG and IgA antibodies were lower in the elderly, as was the frequency of SARS-CoV-2 Spike specific B-memory cells. We observed a trend towards lower somatic hypermutation in participants with suboptimal neutralisation, and elderly participants demonstrated clear reduction in class switched somatic hypermutation, driven by the IgA1/2 isotype. SARS-CoV-2 Spike specific T-cell IFN{gamma} and IL-2 responses fell with increasing age, and both cytokines were secreted primarily by CD4 T cells. We conclude that the elderly are a high risk population that warrant specific measures in order to mitigate against vaccine failure, particularly where variants of concern are circulating.

Impact of SARS-CoV-2 B.1.1.7 Spike variant on neutralisation potency of sera from individuals vaccinated with Pfizer vaccine BNT162b2

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) transmission is uncontrolled in many parts of the world, compounded in some areas by higher transmission potential of the B1.1.7 variant now seen in 50 countries. It is unclear whether responses to SARS-CoV-2 vaccines based on the prototypic strain will be impacted by mutations found in B.1.1.7. Here we assessed immune responses following vaccination with mRNA-based vaccine BNT162b2. We measured neutralising antibody responses following a single immunization using pseudoviruses expressing the wild-type Spike protein or the 8 amino acid mutations found in the B.1.1.7 spike protein. The vaccine sera exhibited a broad range of neutralising titres against the wild-type pseudoviruses that were modestly reduced against B.1.1.7 variant. This reduction was also evident in sera from some convalescent patients. Decreased B.1.1.7 neutralisation was also observed with monoclonal antibodies targeting the N-terminal domain (9 out of 10), the Receptor Binding Motif (RBM) (5 out of 31), but not in neutralising mAbs binding outside the RBM. Introduction of the E484K mutation in a B.1.1.7 background to reflect newly emerging viruses in the UK led to a more substantial loss of neutralising activity by vaccine-elicited antibodies and mAbs (19 out of 31) over that conferred by the B.1.1.7 mutations alone. E484K emergence on a B.1.1.7 background represents a threat to the vaccine BNT162b.

To study the extent of lymph mode dissection and prognostic factors in patients with intrahepatic cholangiocarcinoma / 中华肝胆外科杂志

Objective:To study the impact of patients with intrahepatic cholangiocellular carcinoma (ICC) who underwent surgical resection with or without lymph node dissection (LND), negative or positive lymph node metastasis detected by LND, different extents of LND, and prognostic factors on long-term prognosis of these patients.Methods:The clinical data of 162 patients who were admitted to the Affiliated Cancer Hospital of Zhengzhou University from June 2014 to October 2019 and underwent surgical resection with postoperative histopathological results confirming ICC were retrospectively analyzed. According to the degree of LND, these patients were divided into three groups: the undissected group ( n=68), N0 dissected group (prophylactic dissection) ( n=41) and N1 dissected group (positive dissection, n=53). Of 94 patients who underwent LND, 23 patients underwernt the first station LND (the routine dissection group, n=23), and 71 patients underwent extended LND (the extended dissection group, n=71). The Kaplan-Meier method was used to construct survival curves. Cox regression analysis was used to detect independent factors affecting survival and long-term prognosis of patients. Results:In this study, there were 87 males and 75 females, with a median age of 60 years.The median survival time of these 162 ICC patients was 10 months. The cumulative survival rates at 1-, 3- and 5-year after surgery were 37.6%, 16.5% and 7.9%, respectively. The 1-, 3- and 5-year cumulative survival rates of the N0 dissection group were 52.1%, 31.7% and 25.4%, respectively, which were significantly better than those of the undissected group (34.2%, 12.7%, 3.4%), and the N1 dissection group (30.3%, 11.4%, 0) ( P<0.05). There were no significant differences in postoperative survival between the extended dissection group and the routine dissection group ( P>0.05). Preoperative CA19-9 >50 U/ml ( RR=1.425, 95% CI: 0.962-2.112), maximum tumor diameter > 5 cm ( RR=0.672, 95% CI: 0.456-0.989), without LND ( RR=1.715, 95% CI: 1.140-2.580), positive margin ( RR=0.591, 95% CI: 0.390-0.897), and without postoperative adjuvant therapy ( RR=0.663, 95% CI: 0.504-0.872) were independent risk factors affecting postoperative survival ( P<0.05). Conclusions:LND in ICC patients improved long-term survival outcomes. However, extended LND did not improve prognosis of these patients. The preoperative CA19-9 level, maximum tumor diameter, lymph node dissection, surgical margin status, and postoperative adjuvant therapy were independent risk factors affecting long-term prognosis of these patients.

Numbers of positive lymph nodes predict postoperative survival of intrahepatic cholangiocellular carcinoma patients after radical resection / 中华普通外科杂志

Objective:To evaluate prognostic significance of metastated lymph nodes (LN) in patients with intrahepatic cholangio carcinoma (ICC) after radical resection.Methods:Data were reviewed on 90 patients at Department of Hepatobiliary and Pancreatic Surgery in our hospital from Feb 2013 to Oct 2019, 37 cases had no LN metastasis (N0 group), 21 cases were in N1 group (positive LN<3) and 32 cases in N2 group (positive LN≥3),and Kaplan-Meier method was used to construct survival curve. Univariate and multivariate COX regression analysis was used to screen independent risk factors.Results:In N0 group the 1-and 3-year survival rates were 57.7% and 35.2%, respectively. In N1 group the 1-and 3-year survival rates were 46.7% and 17.5%, respectively in N2 group. the 1-and 3-year survival rates were 19.6% and 0, respectively. There was statistical significance in overall survival rate among the three groups ( χ2=15.272, P<0.05). Multivariate analysis showed that resection margin ( P=0.009) and the number of positive LN ( P=0.002) were independent risk factors affecting the prognosis of patients. Conclusion:Resection margin and the number of metastasing LN were closely related to postoperative prognosis of ICC patients.

Analysis on comparison of inter-laboratory results of chemical volatile organic compounds / 中国职业医学

OBJECTIVE: To analyze the comparison results of volatile organic components in chemicals tested by occupational health laboratories.METHODS: A total of 37 reference laboratories that participated in the 2019 National Occupational Health Inspection and Testing Institution Laboratory Comparison Chemical Qualitative Testing Comparison organized by Guangdong Occupational Health Testing Center were selected as the research subjects. Headspace gas chromatography-mass spectrometry was used for the determination of volatile organic components in chemicals. The comparison results of reference laboratories were collected and implemented with qualitative and quantitative evaluation. RESULTS: The qualified rates of the qualitative results of the required hazard factors and other hazard factors in the reference laboratories were higher than those of the quantitative results of similar factors with statistical significance(83.78% vs 67.57%, 89.19% vs 56.76%, all P<0.05). There was no significant difference in the qualified rate of qualitative and quantitative results and comprehensive judgment results among each reference laboratory with other hazard factors(83.78% vs 89.19%, 67.57% vs 56.76%, 83.78% vs 89.19%, all P>0.05). The qualified rate of 37 reference laboratories was 89.19%(33/37). It showed no significant difference in the qualified rate of qualitative, quantitative and comprehensive judgment results among the reference laboratories of disease prevention and control system and non-disease prevention and control system(93.75% vs 85.72%, 85.00% vs 61.91%, 93.75% vs 85.52%,all P>0.05). CONCLUSION: There are great differences in the detection ability of volatile organic components on chemicals of each reference laboratory. The ability of qualitative detection is superior to the quantitative detection.

Preparation of air sampling tube for chlorobenzene compounds and establishment of its matching detecting method / 中国职业医学

OBJECTIVE: To prepare and develop a GDH-2 air sampling tube for detecting 12 kinds of chlorobenzenes(CBs) in workplace air and to establish a matching detecting method. METHODS: The self-developed GDH-2 air sampling tube was filled with ion exchange resin and activated carbon, and the mass ratio was 10 ∶1. The GDH-2 air sampling tube was used to collect 12 kinds of CBs with coexistence of gaseous and aerosol in the air. After elution with toluene, they were separated on a chromatographic column and determined by microcell electron capture detector. RESULTS: The quantitative detecting range of the method was 0.51×10~(-3)-6 000.00 mg/L, with the correlation coefficients greater than 0.999 4. The minimum detection concentration was 0.02-61.99 μg/m~3, and the minimum quantitative concentration was 0.05-206.62 μg/m~3. The average desorption efficiency was 90.8%-104.0%. The within-run relative standard deviation(RSD) was 1.0%-5.7%, and the between-run RSD was 3.0%-7.3%. The samples can be stored at room temperature for at least 26 days. CONCLUSION: The self-developed GDH-2 air sampling tube and its matching measuring method can be used for the collection and determination of the 12 kinds of CBs in the air of workplace.

Determination of 12 kinds of chlorobenzene compounds in workplace air by portable gas chromatography-mass spectrometry / 中国职业医学

OBJECTIVE: To establish a method for simultaneous determination of 12 kinds of chlorobenzene compound(CBs) in workplace air using portable gas chromatography-mass spectrometry(GC-MS) technique. METHODS: The GDH-3 air sampling tube was developed independently, and were used to collect the 12 kinds of CBs in the vapor state and aerosol state in the air. After elution with toluene solvent, portable GC-MS method was used for detection. Fast chromatographic column was used for separation, and then qualitatively analyzed with retention time and characteristics of the ions, and quantitative analyzed by standard curves. RESULTS: The quantitative determination ranges of the 12 kinds of CBs were 0.20-200.00 mg/L. All the correlative coefficients were greater than 0.998 3. All the minimum quantitative concentration was 0.01 mg/m~3, and all the minimum quantitative mass concentration was 0.04 mg/m~(3 )(15 L sample). The average elution efficiency was 88.97%-116.86%. The within-run and the between-run relative standard deviation was 10.15%-13.48% and 12.87%-19.66%, respectively. All the sampling efficiencies were>90.00%. CONCLUSION: The portable GC-MS technique could be used for rapid qualitative and quantitative detection of 12 kinds of CBs in workplace air.

Determination of methyl pentane in workplace air by solvent desorption-gas chromatography / 中国职业医学

OBJECTIVE: To establish a solvent desorption-gas chromatography method for determination of methyl pentane in workplace air. METHODS: Methyl pentane in workplace air was collected with activated carbon tube and desorbed with carbon disulfide, then separated by DB-1 capillary column, detected by flame ionization detector, and quantified by standard curve method. RESULTS: Good linearity was obtained in the range of 1.98-6 600.00 mg/L with the correlation coefficient of 0.999 9. The minimum detection limit and the minimum quantification limit were 0.06 and 0.20 mg/L, respectively. The minimum detection concentration and minimum quantification concentration was 0.04 and 0.14 mg/m~3, respectively(calculated by collecting 1.5 L of air sample). The average desorption efficiency was 97.3%-102.2%. The within-run relative standard deviation(RSD) and the between-run RSD were 0.4%-0.9% and 0.3%-3.0%, respectively. The sampling efficiency was 96.7%-100.0% and the penetration capacity was 8.68 mg. The samples can be stored at room temperature for at least 14 days. CONCLUSION: This method is suitable for methyl pentane detection in workplace air.

Determination of volatile organic compounds in air using portable gas chromatography-mass spectrometry / 中国职业医学

OBJECTIVE: To explore a method for detecting volatile organic compounds(VOCs) in air by a portable gas chromatography-mass spectrometer(GC-MS). METHODS: A portable GC-MS hand-held probe was used for sampling and detection. All effluent components were qualitatively analyzed by the standard spectral library of the United State National Institute of Standards and Technology. The percentage of peak area of the component was calculated by normalization method. The static distribution method was adopted in the semi-quantitative and quantitative analysis using nitrogen as the diluting gas to prepare different mass concentration of 13 kinds of VOCs in the mixed standard gas. The retention time and characteristic ions were used for qualitative analysis, and the quantitated full scanning mode was used for quantitative analysis.RESULTS: The minimum detected mass concentration of the 13 chemical harmful factors was 0.02-0.10 mg/m~3, and the minimum quantitative mass concentration was 0.07-0.38 mg/m~3. The recovery rate was 84.76%-116.56%, and the within-and between-run relative standard deviations were 4.10%-12.50% and 8.17%-14.36%, respectively. CONCLUSION: The portable GC-MS instrument could be used for qualitative alalysis, peak area percentage determination, semi-quantitative and quantitative analysis of VOCs in the workplace air or sudden chemical poisoning accidents.

Case-control study on the Endobutton plate and clavicular hook plate for the treatment of acromioclavicular joint dislocation / 中国骨伤

OBJECTIVE@#To study the clinical efficacy and complications of Endobutton titanium plate and clavicle hook plate in the treatment of acromioclavicular dislocation.@*METHODS@#Total 48 patients with Rockwood Ⅲ to Ⅴ acromioclavicular joint dislocation from March 2015 to May 2019 were retrospectively divided into two groups according to different surgical methods. Among the patients, 23 patients were treated with Endobutton loop titanium plate fixation (observation group), including 15 males and 8 females, ranging in age from 23 to 59 years old, with an average of(36.2±8.1) years old;Rockwood type Ⅲ in 6 cases, type Ⅳ in 11 cases and type Ⅴ in 6 cases. Twenty-five patients were treated with clavicular hook plate(control group), including 17 males and 8 females, ranging in age from 22 to 54 years old, with an average of (34.7±6.4) years old; Rockwood type Ⅲ in 6 cases, type Ⅳ in 14 cases and type Ⅴ in 5 cases. The operation time, intraoperative bleeding, hospitalization time, visual analogue scale (VAS) of pain, Constant-Murley score of shoulder function and postoperative complications were compared between the two groups.@*RESULTS@#All the patients were followed up, and the duration ranged from 24 to 51 months, with a mean of (30.5±6.5) months. The amountof bleeding and hospitalization time in the observation group were (71.9±4.0) ml and(8.2±1.6) d respectively;and those in the control group were (97.6±13.4) ml and (12.8±1.2) d respectively. There was significant difference between the two groups (@*CONCLUSION@#Compared with clavicular hook plate internal fixation in the treatment of acromioclavicular joint dislocation, Endobutton loop titanium plate internal fixation technology has the advantages of less surgical bleeding, shorter hospitalization time, less postoperative pain, good recovery of shoulder joint function and less complications.

Recurrent emergence and transmission of a SARS-CoV-2 Spike deletion ΔH69/V70

SARS-CoV-2 amino acid replacements in the receptor binding domain (RBD) occur relatively frequently and some have a consequence for immune recognition. Here we report recurrent emergence and significant onward transmission of a six-nucleotide out of frame deletion in the S gene, which results in loss of two amino acids: H69 and V70. We report that in human infections {Delta}H69/V70 often co-occurs with the receptor binding motif amino acid replacements N501Y, N439K and Y453F, and in the latter two cases has followed the RBD mutation. One of the {Delta}H69/V70+ N501Y lineages, now known as B.1.1.7, has undergone rapid expansion and includes eight S gene mutations: RBD (N501Y and A570D), S1 ({Delta}H69/V70 and {Delta}144) and S2 (P681H, T716I, S982A and D1118H). In vitro, we show that {Delta}H69/V70 does not reduce serum neutralisation across multiple convalescent sera. However, {Delta}H69/V70 increases infectivity and is associated with increased incorporation of cleaved spike into virions. {Delta}H69/V70 is able to compensate for small infectivity defects induced by RBD mutations N501Y, N439K and Y453F. In addition, replacement of H69 and V70 residues in the B.1.1.7 spike reduces its infectivity and spike mediated cell-cell fusion. Based on our data {Delta}H69/V70 likely acts as a permissive mutation that allows acquisition of otherwise deleterious immune escape mutations. Enhanced surveillance for the {Delta}H69/V70 deletion with and without RBD mutations should be considered as a global priority not only as a marker for the B.1.1.7 variant, but potentially also for other emerging variants of concern. Vaccines designed to target the deleted spike protein could mitigate against its emergence as increased selective forces from immunity and vaccines increase globally. HighlightsO_LI{Delta}H69/V70 is present in at least 28 SARS-CoV-2 lineages C_LIO_LI{Delta}H69/V70 does not confer escape from convalescent sera C_LIO_LI{Delta}H69/V70 increases spike infectivity and compensates for RBD mutations C_LIO_LI{Delta}H69/V70 is associated with greater spike cleavage C_LIO_LIB.1.1.7 requires {Delta}H69/V70 for optimal spike cleavage and infectivity C_LI