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.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Grain size is an important component trait of grain yield, which is frequently threatened by abiotic stress. However, little is known about how grain yield and abiotic stress tolerance are regulated. ...Here, we characterize GSA1, a quantitative trait locus (QTL) regulating grain size and abiotic stress tolerance associated with metabolic flux redirection. GSA1 encodes a UDP-glucosyltransferase, which exhibits glucosyltransferase activity toward flavonoids and monolignols. GSA1 regulates grain size by modulating cell proliferation and expansion, which are regulated by flavonoid-mediated auxin levels and related gene expression. GSA1 is required for the redirection of metabolic flux from lignin biosynthesis to flavonoid biosynthesis under abiotic stress and the accumulation of flavonoid glycosides, which protect rice against abiotic stress. GSA1 overexpression results in larger grains and enhanced abiotic stress tolerance. Our findings provide insights into the regulation of grain size and abiotic stress tolerance associated with metabolic flux redirection and a potential means to improve crops.
This study aims to investigate the anticancer properties of Citrus grandis 'Tomentosa' (CGT) in non-small cell lung cancer (NSCLC).
The ethanol extract of CGT (CGTE) is prepared by using anhydrous ...ethanol and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), revealing that the main chemical components in CGTE are flavonoids and coumarins, such as naringin, rhoifolin, apigenin, bergaptol, and osthole. CGTE at concentrations without inducing cell death significantly inhibits cell proliferation via inducing cell cycle G1 phase arrest by MTT, colony formation, and flow cytometry assays, implying that CGT has anticancer potential. CGTE markedly inhibits the activity of Skp2-SCF E3 ubiquitin ligase, decreases the protein level of Skp2, and promotes the accumulation of p27 by co-immunoprecipitation (co-IP) and in vivo ubiquitination assay; whereas Skp2 overexpression rescues the effects of CGTE in NSCLC cells. In subcutaneous LLC allograft and A549 xenograft mouse models, CGTE, without causing obvious side effects in mice, significantly inhibits lung tumor growth by targeting the Skp2/p27 signaling pathway.
These findings demonstrate that CGTE efficiently inhibits NSCLC proliferation both in vitro and in vivo by targeting the Skp2/p27 signaling pathway, suggesting that CGTE may serve as a therapeutic candidate for NSCLC treatment.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The platform consists of three modules, which are pre‐configured bioinformatic pipelines, cloud toolsets, and online omics' courses. The pre‐configured bioinformatic pipelines not only combine ...analytic tools for metagenomics, genomes, transcriptome, proteomics and metabolomics, but also provide users with powerful and convenient interactive analysis reports, which allow them to analyze and mine data independently. As a useful supplement to the bioinformatics pipelines, a wide range of cloud toolsets can further meet the needs of users for daily biological data processing, statistics, and visualization. The rich online courses of multi‐omics also provide a state‐of‐art platform to researchers in interactive communication and knowledge sharing.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
As a type of elementary organic compounds containing N−N single bond, hydrazone involved chemical conversions are extremely extensive, but they are mainly limited to N2‐retention and N2‐removal ...modes. We report herein an unprecedented protocol for the realization of division utilization of the N2‐moiety of hydrazone by a radical facilitated N−N bond deconstruction strategy. This new conversion mode enables the successful combination of alkene carboamination and Hofmann‐Löffler‐Freytag reaction by the reaction of N‐homoallyl mesitylenesulfonyl hydrazones with ethyl difluoroiodoacetate under photocatalytic redox neutral conditions. Mechanism studies reveal that the reaction undergoes a radical relay involving addition, crucial remote imino‐N migration and H‐atom transfer. Consequently, a series of structurally significant ϵ‐N‐sulphonamide‐α,α‐difluoro‐γ‐amino acid esters are efficiently produced via continuous C−C bond and dual C−N bonds forging.
A novel conversion mode for hydrazone by the division use of N2‐moiety is developed by the photocatalytic redox neutral reaction of N‐homoallyl‐N‐mesitylenesulfonyl (Mts)‐hydrazones with ICF2CO2Et. The reaction merges olefin carboamination and Hofmann‐Löffler‐Freytag (HLF) reaction by radical addition/crucial distal N and H transfer sequences to yield ϵ‐N‐sulphonamide‐α,α‐difluoro‐γ‐amino acid esters under tandem C−C and dual C−N bonds forging.
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•The superiority of a hybrid microchannel cooling compared to MMC heat sink is verified by single-phase HFE-7100.•The pressure drop and thermal resistance can be both reduced due to the combining ...benefits of manifold and secondary flow.•Increasing flow rate will bring an enhanced ability of reducing thermal resistance and a suppressed ability of reducing pressure drop.•The hybrid heat sink still has a better hydraulic performance compared to MMC heat sink even though the reynolds number reaches up to 883.
It is highly desired to efficiently dissipate the high heat flux generated in electronics. A novel hybrid microchannel heat sink combining manifold with secondary oblique channels (MMC-SOC) has been proposed and studied numerically in our previous work. The current study conducts the fabrication and experimental test of the hybrid microchannel heat sink using dielectric fluid HFE-7100. The volume flow rate qv ranges from 211 to 580 mL/min, with channel Reynolds numbers between 278 and 905 for heat fluxes q'' = 20, 25, 30 and 35 W/cm2. The results indicate that the MMC-SOC heat sink can simultaneously reduce the thermal resistance Rt and pressure drop ∆P. For heat sinks with channel height Hc = 60 μm, an 11% reduction in ∆P and a 24% reduction in Rt are obtained compared to conventional manifold microchannel (MMC) heat sink for qv = 580 mL/min and q'' = 20 W/cm2. As qv increases, the ratio (Rt/Rt0) becomes smaller and (∆P/∆P0) becomes larger, which indicates an enhanced ability of reducing Rt and a suppressed ability of reducing ∆P. For the maximum qv = 580 mL/min and q'' = 35 W/cm2, the MMC-SOC heat sink can maintain a maximum chip temperature of 53 °C with a pressure drop of only 3.77 kPa. Moreover, the proposed MMC-SOC heat sink has a lower pressure drop compared to MMC heat sink owing to a reasonable design, even though the Reynolds number of the MMC-SOC heat sink reaches up to 883. This provides a very promising scheme for safe and efficient single-phase microchannel cooling used in the thermal management of electronics with high heat flux. In addition, the ratio (Rt/Rt0) will increase with increasing heat flux and increasing the flow rate becomes an effective way to further reduce the chip surface temperature at operating conditions with higher heat flux.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Lowering the entropy
Atoms loaded in an optical lattice can convincingly mimic the behavior of electrons in solids. However, reaching very low temperatures, where the most interesting quantum phases ...are expected to occur, is tricky. Yang
et al.
introduced a clever experimental technique to reduce the entropy of their sample. They created an array consisting of alternating rows of sample atoms and reservoirs. The entropy was transferred from the sample atoms to the adjacent reservoirs, which were then removed. The resulting low-entropy system can be used as a basis for quantum simulation and information.
Science
, this issue p.
550
An entropy redistribution scheme is developed for applications in quantum simulation and information processing.
Scalable, coherent many-body systems can enable the realization of previously unexplored quantum phases and have the potential to exponentially speed up information processing. Thermal fluctuations are negligible and quantum effects govern the behavior of such systems with extremely low temperature. We report the cooling of a quantum simulator with 10,000 atoms and mass production of high-fidelity entangled pairs. In a two-dimensional plane, we cool Mott insulator samples by immersing them into removable superfluid reservoirs, achieving an entropy per particle of
1.9
−
0.4
+
1.7
×
10
−
3
k
B
. The atoms are then rearranged into a two-dimensional lattice free of defects. We further demonstrate a two-qubit gate with a fidelity of 0.993 ± 0.001 for entangling 1250 atom pairs. Our results offer a setting for exploring low-energy many-body phases and may enable the creation of large-scale entanglement.
How the plasma membrane senses external heat-stress signals to communicate with chloroplasts to orchestrate thermotolerance remains elusive. We identified a quantitative trait locus,
Thermo-tolerance ...3
(
TT3
), consisting of two genes,
TT3.1
and
TT3.2
, that interact together to enhance rice thermotolerance and reduce grain-yield losses caused by heat stress. Upon heat stress, plasma membrane–localized E3 ligase TT3.1 translocates to the endosomes, on which TT3.1 ubiquitinates chloroplast precursor protein TT3.2 for vacuolar degradation, implying that TT3.1 might serve as a potential thermosensor. Lesser accumulated, mature TT3.2 proteins in chloroplasts are essential for protecting thylakoids from heat stress. Our findings not only reveal a
TT3.1-TT3.2
genetic module at one locus that transduces heat signals from plasma membrane to chloroplasts but also provide the strategy for breeding highly thermotolerant crops.
Heat tolerance in rice
Too much heat can damage a plant’s chloroplasts, driving yield down when temperatures exceed a crop’s normal tolerance. Zhang
et al
. identified a locus with two genes that together enhance rice thermotolerance. The ubiquitin ligase activity of Thermo-tolerance 3.1 (TT3.1) drove degradation of TT3.2, a chloroplast precursor protein that can trigger chloroplast damage in the context of heat stress. Together, these protein products respond to heat and control the damage. —PJH
A tag team of protein degradation protects rice plants from excess heat.
Over-application of nitrogen fertilizer in fields has had a negative impact on both environment and human health. Domesticated rice varieties with high nitrogen use efficiency (NUE) reduce fertilizer ...for sustainable agriculture. Here, we perform genome-wide association analysis of a diverse rice population displaying extreme nitrogen-related phenotypes over three successive years in the field, and identify an elite haplotype of nitrate transporter OsNPF6.1
that enhances nitrate uptake and confers high NUE by increasing yield under low nitrogen supply. OsNPF6.1
differs in both the protein and promoter element with natural variations, which are differentially trans-activated by OsNAC42, a NUE-related transcription factor. The rare natural allele OsNPF6.1
, derived from variation in wild rice and selected for enhancing both NUE and yield, has been lost in 90.3% of rice varieties due to the increased application of fertilizer. Our discovery highlights this NAC42-NPF6.1 signaling cascade as a strategy for high NUE and yield breeding in rice.
Previous studies have shown that fibrinogen-to-albumin ratio (FAR) is a novel prognostic immune biomarker in various diseases. In this study, we investigated the role of FAR in the prognosis of ...patients with stage IB-IIA cervical cancer (CC).
A total of 278 eligible participants with newly diagnosed CC (stage IB-IIA) who had undergone radical hysterectomy followed by adjuvant chemotherapy were enrolled in this study. Demographics, clinicopathological variables, and laboratory tests were obtained from the medical records. Risk factors for overall survival (OS) and recurrence-free survival (RFS) were evaluated by univariate and multivariate Cox proportional regression analyses. The association between OS, RFS, and FAR was assessed by the Kaplan-Meier method using log-rank test.
FAR was associated with age, International Federation of Gynecology and Obstetrics (FIGO) stage, depth of the invasion, and C-reactive protein (CRP) level (P < 0.05). Preoperative FAR was an effective predictor for OS in CC patients with a cut-off value of 7.75 and an area under the curve (AUC) of 0.707 (P < 0.001). The univariate and multivariate Cox analyses indicated that FIGO stage and FAR were two independent risk factors for both OS and RFS (P < 0.05). Kaplan-Meier analysis confirmed that patients with high FAR levels showed significantly lower RFS (P = 0.004) and OS (P = 0.003) than those with low FAR levels.
This study indicated that elevated preoperative FAR might be a novel prognostic factor for CC patients with stage IB-IIA.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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