Relationship of various COVID-19 antibody titer with individual characteristics and prediction of future epidemic trend in Xiamen City, China.

Background: Reinfection of coronavirus disease 2019 (COVID-19) has raised concerns about how reliable immunity from infection and vaccination is. With mass testing for the virus halted, understanding the current prevalence of COVID-19 is crucial. This study investigated 1,191 public health workers at the Xiamen Center for Disease Control, focusing on changes in antibody titers and their relationship with individual characteristics. Methods: The study began by describing the epidemiological characteristics of the study participants. Multilinear regression (MLR) models were employed to explore the associations between individual attributes and antibody titers. Additionally, group-based trajectory models (GBTMs) were utilized to identify trajectories in antibody titer changes. To predict and simulate future epidemic trends and examine the correlation of antibody decay with epidemics, a high-dimensional transmission dynamics model was constructed. Results: Analysis of epidemiological characteristics revealed significant differences in vaccination status between infected and non-infected groups (χ2=376.706, P<0.05). However, the distribution of antibody titers among the infected and vaccinated populations was not significantly different. The MLR model identified age as a common factor affecting titers of immunoglobulin G (IgG), immunoglobulin M (IgM), and neutralizing antibody (NAb), while other factors showed varying impacts. History of pulmonary disease and hospitalization influenced IgG titer, and factors such as gender, smoking, family history of pulmonary diseases, and hospitalization impacted NAb titers. Age was the sole determinant of IgM titers in this study. GBTM analysis indicated a "gradual decline type" trajectory for IgG (95.65%), while IgM and NAb titers remained stable over the study period. The high-dimensional transmission dynamics model predicted and simulated peak epidemic periods in Xiamen City, which correlated with IgG decay. Age-group-specific simulations revealed a higher incidence and infection rate among individuals aged 30-39 years during both the second and third peaks, followed by those aged 40-49, 50-59, 18-29, and 70-79 years. Conclusions: Our study shows that antibody titer could be influenced by age, previous pulmonary diseases as well as smoking. Furthermore, the decline in IgG titers is consistent with epidemic trends. These findings emphasize the need for further exploration of these factors and the development of optimized self-protection countermeasures against reinfection.

Dirhodium(II)/DPPM Catalyzed 1,2-Hydrosilylation of Conjugated Dienes with Tertiary Silanes.

A simple and efficient Rh2(OAc)4/DPPM (bis(diphenylphosphanyl)methane) catalyzed regioselective 1,2-anti-Markovnikov hydrosilylation of conjugated dienes with various tertiary silanes gave homoallylic silanes in acetonitrile, which tolerate broad functional groups. Control experiments proved that no π-allyl transition metal intermediates were involved in this 1,2-anti-Markovnikov hydrosilylation. Dirhodium hydride species was observed in hydrosilylation, suggesting that a direct insertion of the terminal double bond into a Rh-H bond is involved in this reaction.

Effectiveness of Inactivated Vaccine against SARS-CoV-2 Delta Variant Infection in Xiamen, China-A Test-Negative Case-Control Study.

OBJECTIVE: Vaccine effectiveness can measure herd immunity, but the effectiveness of inactivated vaccines in Xiamen remains unclear. Our study was designed to understand the herd immunity of the COVID-19 inactivated vaccine against the SARA-CoV-2 Delta variant in the real world of Xiamen. METHODS: We carried out a test-negative case-control study to explore the vaccine's effectiveness. Participants aged over 12 years were recruited. A logistic regression was used to estimate the odds ratio (OR) of the vaccine among cases and controls. RESULTS: This outbreak began with factory transmission clusters, and spread to families and communities during the incubation period. Sixty percent of cases were confirmed in a quarantine site. A huge mass of confirmed cases (94.49%) was identified within three days, and nearly half of them had a low Ct value. Following an adjustment for age and sex, a single dose of inactivated SARS-CoV-2 vaccine yielded the vaccine effectiveness (VE) of the overall case, of 57.01% (95% CI: -91.44~86.39%), the fully VE was 65.72% (95% CI: -48.69~88.63%) against COVID-19, 59.45% against moderate COVID-19 and 38.48% against severe COVID-19, respectively. The VE of fully vaccinated individuals was significantly higher in females than in males (73.99% vs. 46.26%). The VE among participants aged 19~40 and 41~61 years was 78.75% and 66.33%, respectively, which exceeds the WHO's minimal threshold. Nevertheless, the VE in people under 18 and over 60 years was not observed because of the small sample size. CONCLUSIONS: The single-dose vaccine had limited effectiveness in preventing infection of the Delta variant. The two doses of inactivated vaccine could effectively prevent infection, and clinical mild, moderate, and severe illness caused by the SARS-CoV-2 Delta variant in people aged 18-60 years in the real world.

Moscatilin suppresses the inflammation from macrophages and T cells.

In this study, we aim to investigate moscatilin in alleviating symptoms of autoimmune liver disease (ALD) in a concanavalin A (ConA)-induced liver injury mouse model and elucidate the underlying mechanisms. ALD mouse models were constructed by intravenous injection of ConA (20 mg/kg) and the serum level of alanine aminotransferase (ALT) was measured using an enzyme-linked immunosorbent assay. Moscatilin in various doses was administered for two days starting from a day before the ConA injection. We showed that moscatilin dose-dependently decreased ALT levels in liver tissue of ALD mouse models. Ifng and Tnfa also showed significant downregulation in liver tissues. Macrophages only showed significant Tnfa downregulation and CD4+ T cells only showed significant Ifng downregulation at high moscatilin doses. In vivo administration of moscatilin induced interleukin-37 upregulation in hepatic tissues. In vitro, moscatilin also induced IL-37 upregulation in hepatic stellate cell line JS-1 rather than immune cells represented by RAW264.7 and CTLL-2 cell lines, suggesting that the hepatic stellate cell is majorly responsive to moscatilin treatment in terms of interleukin (IL)-37 upregulation. Our data indicate that moscatilin could alleviate liver injury in ConA-induced ALD mouse models through anti-inflammatory activities, warranting further development of moscatilin as a new drug in treating ALD.

Correlation between mumps and meteorological factors in Xiamen City, China: A modelling study.

Objective: Mumps is a seasonal infectious disease, always occurring in winter and spring. In this study, we aim to analyze its epidemiological characteristics, transmissibility, and its correlation with meteorological variables. Method: A seasonal Susceptible-Exposed-Infectious/Asymptomatic-Recovered model and a next-generation matrix method were applied to estimate the time-dependent reproduction number (R t ). Results: The seasonal double peak of annual incidence was mainly in May to July and November to December. There was high transmission at the median of R t  = 1.091 (ranged: 0 to 4.393). R t was seasonally distributed mainly from February to April and from September to November. Correlations were found between temperature (Pearson correlation coefficient [r] ranged: from 0.101 to 0.115), average relative humidity (r = 0.070), average local pressure (r = -0.066), and the number of new cases. In addition, average local pressure (r = 0.188), average wind speed (r = 0.111), air temperature (r ranged: -0.128 to -0.150), average relative humidity (r = -0.203) and sunshine duration (r = -0.075) were all correlated with R t . Conclusion: A relatively high level of transmissibility has been found in Xiamen City, leading to a continuous epidemic of mumps. Meteorological factors, especially air temperature and relative humidity, may be more closely associated with mumps than other factors.

Nickel-Catalyzed Hydrosilylation of Terminal Alkenes with Primary Silanes via Electrophilic Silicon-Hydrogen Bond Activation.

We report a simple and effective nickel-based catalytic system, NiCl2·6H2O/tBuOK, for the electrophilically activated hydrosilylation of terminal alkenes with primary silanes. This protocol provides excellent performance under mild reaction conditions: exclusive anti-Markovnikov selectivity, broad functional group tolerance (36 examples), and good scalability (TON = 5500). However, the secondary and tertiary silanes are not suitable. Mechanistic studies revealed that this homogeneous catalytic hydrosilylation includes an electrophilically activated Si-H bond process without the generation of nickel hydrides.

Ru-Catalyzed Chemo- and Enantioselective Hydrogenation of 2,4-Pentadien-1-ones: Synthesis of Chiral 2,4-Pentadien-1-ols.

The asymmetric hydrogenation of 2,4-pentadien-1-ones has been achieved by using trans-RuCl2[(R)-XylylSunPhos][(R)-Daipen] as a catalyst under basic conditions. This hydrogenation demonstrated exclusive C1-carbonyl selectivity, and thus the conjugated 2,4-diene motifs remained untouched, which provides a synthetically useful method for various chiral 2,4-pentadien-1-ols.

Direct Synthesis of Alkenylboronates from Alkenes and Pinacol Diboron via Copper Catalysis.

We report an efficient approach for the direct synthesis of alkenylboronates using copper catalysis. The Cu/TEMPO catalyst system (where TEMPO = (2,2,6,6-tetramethylpiperidin-1-yl)oxyl) exhibits both excellent reactivity and selectivity for the synthesis of alkenylboronates, starting from inexpensive and abundant alkenes and pinacol diboron. This approach allows for the direct functionalization of both aromatic and aliphatic terminal alkenes. Mechanistic experiments suggest that the alkenylboronates arise from oxyboration intermediates.

Alkoxide-Catalyzed Hydrosilylation of Cyclic Imides to Isoquinolines via Tandem Reduction and Rearrangement.

An alkoxide-catalyzed hydrosilylation of cyclic imides to isoquinolines was realized via tandem reduction and rearrangement. Using TMSOK as the catalyst and (EtO)2MeSiH as the reductant, a series of cyclic imides containing different functional groups were reduced to the corresponding 3-aryl isoquinolines in moderate to good yields. The scenario of the reaction pathway was supposed to involve the reduction of imides to ω-hydroxylactams, which underwent rearrangement in the presence of a base catalyst, and then the carbonyl reduction, followed by siloxy elimination.

Copper-catalyzed aromatic C-H alkoxylation with alcohols under aerobic conditions.

An efficient protocol for copper-catalyzed aromatic C-H alkoxylation with alcohols has been developed under aerobic conditions. The protocol provides a complementary method to couple arenes and alcohols to furnish aromatic ethers. The advantages of this method are the employment of a cheap Cu(OAc)2 catalyst, oxygen as the terminal oxidant and alcohol as both an alkoxy reagent and a solvent. Notably, the catalytic amount of benzoic acid plays a significant role in this transformation.

Acetonitrile as a cyanating reagent: Cu-catalyzed cyanation of arenes.

A novel approach to the Cu-catalyzed cyanation of simple arenes using acetonitrile as an attractive cyano source has been documented. The C-H functionalization of arenes without directing groups involves a sequential iodination/cyanation to give the desired aromatic nitriles in good yields. A highly efficient Cu/TEMPO system for acetonitrile C-CN bond cleavage has been discovered. TEMPO is used as a cheap oxidant and enables the reaction to be catalytic in copper. Moreover, TEMPOCH2CN 6 has been identified as the active cyanating agent and shows high reactivity for forming the -CN moiety.