Wuhan was the first epicentre of COVID-19 in the world, accounting for 80% of cases in China during the first wave. We aimed to assess household transmissibility of severe acute respiratory syndrome ...coronavirus 2 (SARS-CoV-2) and risk factors associated with infectivity and susceptibility to infection in Wuhan.
This retrospective cohort study included the households of all laboratory-confirmed or clinically confirmed COVID-19 cases and laboratory-confirmed asymptomatic SARS-CoV-2 infections identified by the Wuhan Center for Disease Control and Prevention between Dec 2, 2019, and April 18, 2020. We defined households as groups of family members and close relatives who did not necessarily live at the same address and considered households that shared common contacts as epidemiologically linked. We used a statistical transmission model to estimate household secondary attack rates and to quantify risk factors associated with infectivity and susceptibility to infection, accounting for individual-level exposure history. We assessed how intervention policies affected the household reproductive number, defined as the mean number of household contacts a case can infect.
27 101 households with 29 578 primary cases and 57 581 household contacts were identified. The secondary attack rate estimated with the transmission model was 15·6% (95% CI 15·2–16·0), assuming a mean incubation period of 5 days and a maximum infectious period of 22 days. Individuals aged 60 years or older were at a higher risk of infection with SARS-CoV-2 than all other age groups. Infants aged 0–1 years were significantly more likely to be infected than children aged 2–5 years (odds ratio OR 2·20, 95% CI 1·40–3·44) and children aged 6–12 years (1·53, 1·01–2·34). Given the same exposure time, children and adolescents younger than 20 years of age were more likely to infect others than were adults aged 60 years or older (1·58, 1·28–1·95). Asymptomatic individuals were much less likely to infect others than were symptomatic cases (0·21, 0·14–0·31). Symptomatic cases were more likely to infect others before symptom onset than after (1·42, 1·30–1·55). After mass isolation of cases, quarantine of household contacts, and restriction of movement policies were implemented, household reproductive numbers declined by 52% among primary cases (from 0·25 95% CI 0·24–0·26 to 0·12 0·10–0·13) and by 63% among secondary cases (from 0·17 0·16–0·18 to 0·063 0·057–0·070).
Within households, children and adolescents were less susceptible to SARS-CoV-2 infection but were more infectious than older individuals. Presymptomatic cases were more infectious and individuals with asymptomatic infection less infectious than symptomatic cases. These findings have implications for devising interventions for blocking household transmission of SARS-CoV-2, such as timely vaccination of eligible children once resources become available.
National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities, US National Institutes of Health, and US National Science Foundation.
Medical humanities education is an important part of medical education. The purpose of this study was to determine the effectiveness of medical humanities in improving empathy among medical students ...and healthcare professionals.
PubMed, Embase, EBSCO-ERIC, Web of Science were searched systematically for studies in the English language. The last retrieval date is May 1, 2023. Best Evidence Medical Education (BEME) Global Rating Scale and Kirkpatrick-based results were used to evaluate the quality of literature. In this study, a meta-analysis of continuous data was conducted.
The pooled results by single-arm test meta-analysis showed a benefit with medical humanities programs in empathy (SMD 1.33; 95% CI 0.69-1.96). For single-arm trials of medical humanities program interventions of less than 4 months, 4 months to 12 months, and more than one year, the standardized mean differences(SMD) between post-test and pre-test were 1.74 (P < 0.05), 1.26 (P < 0.05), and 0.13 (P = 0.46), respectively. The results showed a significant difference in the effect of medical humanities programs on male and female empathy (SMD - 1.10; 95% CI -2.08 - -0.13). The SMDs for the study of course, the course combined reflective writing, and the course combined reflective writing and practice as intervention modalities for medical humanities programs were 1.15 (P < 0.05), 1.64 (P < 0.05), and 1.50 (P < 0.05), respectively.
Medical humanities programs as a whole can improve the empathy of medical students and health professionals. However, different intervention durations and different intervention methods produce different intervention effects.
A generic small-signal model of modular multilevel converter (MMC) based DC grid is established and a DC virtual impedance damping control to suppress the resonance and instability is proposed. The ...averaged-value model (AVM) of MMC is employed to derive the Thévenin equivalent model of the converter from its DC side using the power-balancing principle considering the dynamics of phase-locked loop (PLL) of the interconnected ac system. The single section π-typed line model is selected to develop the nodal admittance equations of the DC network in s domain. The stability criterion of the DC grid is given after establishing the generic linearization model. The key factors affecting the DC grid's stability are identified using the root locus method and participation factors analysis. The parameters and the performances of the damping controller are designed and studied. Electromagnetic transient simulation model and RT-LAB real-time simulation are used to validate that the proposed damping control can suppress the instability of the DC grid and improve its operating performance.
In Dunaliella tertiolecta, a microalga renowned for its extraordinary tolerance to high salinity levels up to 4.5 M NaCl, the mechanisms underlying its stress response have largely remained a ...mystery. In a groundbreaking discovery, this study identifies a choline dehydrogenase enzyme, termed DtCHDH, capable of converting choline to betaine aldehyde. Remarkably, this is the first identification of such an enzyme not just in D. tertiolecta but across the entire Chlorophyta. A 3D model of DtCHDH was constructed, and molecular docking with choline was performed, revealing a potential binding site for the substrate. The enzyme was heterologously expressed in E. coli Rosetta (DE3) and subsequently purified, achieving enzyme activity of 672.2 U/mg. To elucidate the role of DtCHDH in the salt tolerance of D. tertiolecta, RNAi was employed to knock down DtCHDH gene expression. The results indicated that the Ri‐12 strain exhibited compromised growth under both high and low salt conditions, along with consistent levels of DtCHDH gene expression and betaine content. Additionally, fatty acid analysis indicated that DtCHDH might also be a FAPs enzyme, catalyzing reactions with decarboxylase activity. This study not only illuminates the role of choline metabolism in D. tertiolecta's adaptation to high salinity but also identifies a novel target for enhancing the NaCl tolerance of microalgae in biotechnological applications.
Triple negative breast cancer (TNBC) is associated with poor prognosis and systemic chemotherapy is the only treatment for TNBC. However, development of chemo-resistance remains a major obstacle for ...TNBC treatment. Paclitaxel-resistance is mainly related to the activation of the Akt signaling pathway and deregulation of apoptotic regulatory proteins. LncRNAs are frequently dysregulated in various malignancies, including breast cancer, facilitating cell proliferation, metastasis and drug resistance. LncRNA H19 is overexpressed in approximately 70% of breast cancer patients, and has been reported to confer chemo-resistance in breast cancer. In the present study, we investigated the expression level of lncRNA H19 in paclitaxel-resistant and paclitaxel-sensitive cell lines. The results showed that the level of lncRNA H19 expression in paclitaxel-resistant cells was significantly higher than that in paclitaxel-sensitive cells, and knockdown of lncRNA H19 might restore chemo-sensitivity in paclitaxel-resistant TNBC by mediating the AKT signaling pathway. Thus, lncRNA H19 might be an efficient therapeutic target in paclitaxel-resistant TNBC treatment.
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•Development of chemo-resistance remains a major obstacle for TNBC treatment.•LncRNA H19 is overexpressed and confers chemo-resistance in breast cancer.•Knockdown of H19 might restore chemo-sensitivity in paclitaxel-resistant TNBC.•Knockdown of H19 suppresses Akt signaling pathway to trigger apoptosis.
A dc-dc converter is essential for interconnecting HVdc networks of different voltage levels. This letter introduces a new family of dc-dc converters consisting of semiconductor switches and stack of ...submodules, which is named as hybrid-cascaded dc-dc converter (HCDC). This concept shows very attractive capital costs and low power losses. In this letter, the detailed operating principle of the HCDC is analyzed. Simulation results are obtained from PSCAD/EMTDC to verify the feasibility of the converters. The performances of the converters are evaluated in detail.
Hybrid Electric Vehicles (HEVs) have been proven to be a promising solution to environmental pollution and fuel savings. The benefit of the solution is generally realized as the amount of fuel ...consumption saved, which by itself represents a challenge to develop the right energy management strategies (EMSs) for HEVs. Moreover, meeting the design requirements are essential for optimal power distribution at the price of conflicting objectives. To this end, a significant number of EMSs have been proposed in the literature, which require a categorization method to better classify the design and control contributions, with an emphasis on fuel economy, providing power demand, and real-time applicability. The presented review targets two main headlines: (a) offline EMSs wherein global optimization-based EMSs and rule-based EMSs are presented; and (b) online EMSs, under which instantaneous optimization-based EMSs, predictive EMSs, and learning-based EMSs are put forward. Numerous methods are introduced, given the main focus on the presented scheme, and the basic principle of each approach is elaborated and compared along with its advantages and disadvantages in all aspects. In this sequel, a comprehensive literature review is provided. Finally, research gaps requiring more attention are identified and future important trends are discussed from different perspectives. The main contributions of this work are twofold. Firstly, state-of-the-art methods are introduced under a unified framework for the first time, with an extensive overview of existing EMSs for HEVs. Secondly, this paper aims to guide researchers and scholars to better choose the right EMS method to fill in the gaps for the development of future-generation HEVs.
Bombyx mori nucleopolyhedrovirus (BmNPV) is one of the primary pathogens of the silkworm.
(
) showed a significant response to BmNPV infection in our previous transcriptome study. However, little is ...known about the role of
cytc (Bmcytc) in resistance to BmNPV infection. In this study, the expression levels analysis of
showed stable expression levels in selected tissues of the resistant strain AN following BmNPV infection, while there was downregulation in the susceptible strain p50, except in the malpighian tubule. To further study the role of
in viral infection,
was knocked down with siRNA in vitro, resulting in significant downregulation of selected downstream genes of the mitochondrial pathway, including
,
, and
; this was also confirmed by overexpression of
using the pIZT/V5-His-mCherry insect vector, except
. Moreover, knockdown of
significantly promoted the infection process of BmNPV in vitro, while the infection was inhibited by overexpression of
at the early stage and subsequently increased rapidly. Based on these results, we concluded that
plays a vital role in BmNPV infection by regulating the mitochondrial apoptosis pathway. Our work provides valuable data for the clarification of the mechanism of silkworm resistance to BmNPV infection.
State of Charge (SOC) is essential for a smart Battery Management System (BMS). Traditional SOC estimation methods of lithium-ion batteries are usually conducted using battery equivalent circuit ...models (ECMs) and the impact of current sensor bias on SOC estimation is rarely considered. For this reason, this paper proposes an online SOC estimation based on a simplified electrochemical model (EM) for lithium-ion batteries considering sensor bias. In EM-based SOC estimation structure, the errors from the current sensor bias are addressed by proportional–integral observer. Then, the accuracy of the proposed EM-based SOC estimation is validated under different operating conditions. The results indicate that the proposed method has good performance and high accuracy in SOC estimation for lithium-ion batteries, which facilitates the on-board application in advanced BMS.
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