The World Health Organization has declared SARS-CoV-2 virus outbreak a worldwide pandemic. However, there is very limited understanding on the immune responses, especially adaptive immune responses ...to SARS-CoV-2 infection. Here, we collected blood from COVID-19 patients who have recently become virus-free, and therefore were discharged, and detected SARS-CoV-2-specific humoral and cellular immunity in eight newly discharged patients. Follow-up analysis on another cohort of six patients 2 weeks post discharge also revealed high titers of immunoglobulin G (IgG) antibodies. In all 14 patients tested, 13 displayed serum-neutralizing activities in a pseudotype entry assay. Notably, there was a strong correlation between neutralization antibody titers and the numbers of virus-specific T cells. Our work provides a basis for further analysis of protective immunity to SARS-CoV-2, and understanding the pathogenesis of COVID-19, especially in the severe cases. It also has implications in developing an effective vaccine to SARS-CoV-2 infection.
•SARS-CoV-2-specific antibodies are detected in COVID-19 convalescent subjects•Most COVID-19 convalescent individuals have detectable neutralizing antibodies•Cellular immune responses to SARS-CoV-2 are found in COVID-19 convalescent subjects•Neutralization antibody titers correlate with the numbers of virus-specific T cells.
In blood samples from COVID-19 convalescent subjects, Ni et al. have detected SARS-CoV-2-specific humoral and cellular immunity. Most subjects display serum neutralizing activities, which correlate with the numbers of virus-specific T cells.
Developing highly efficient and low‐cost photocatalysts for overall water splitting has long been a pursuit for converting solar power into clean hydrogen energy. Herein, we demonstrate that a ...nonstoichiometric nickel–cobalt double hydroxide can achieve overall water splitting by itself upon solar light irradiation, avoiding the consumption of noble‐metal co‐catalysts. We employed an intensive laser to ablate a NiCo alloy target immersed in alkaline solution, and produced so‐called L‐NiCo nanosheets with a nonstoichiometric composition and O2−/Co3+ ions exposed on the surface. The nonstoichiometric composition broadens the band gap, while O2− and Co3+ ions boost hydrogen and oxygen evolution, respectively. As such, the photocatalyst achieves a H2 evolution rate of 1.7 μmol h−1 under AM 1.5G sunlight irradiation and an apparent quantum yield (AQE) of 1.38 % at 380 nm.
A single‐phase photocatalyst, a hydrogen‐deficient nickel–cobalt double hydroxide, was generated by laser ablation. This photocatalyst can drive overall water splitting under solar light irradiation in the absence of sacrificial agents and noble metal co‐catalysts because of its unique composition and structure, with partially removed hydrogen atoms as well as O2− and Co3+ ions exposed on the surface.
Zika virus (ZIKV) has become a public health threat due to its global transmission and link to severe congenital disorders. The host immune responses to ZIKV infection have not been fully elucidated, ...and effective therapeutics are not currently available. Herein, we demonstrated that cholesterol-25-hydroxylase (CH25H) was induced in response to ZIKV infection and that its enzymatic product, 25-hydroxycholesterol (25HC), was a critical mediator of host protection against ZIKV. Synthetic 25HC addition inhibited ZIKV infection in vitro by blocking viral entry, and treatment with 25HC reduced viremia and conferred protection against ZIKV in mice and rhesus macaques. 25HC suppressed ZIKV infection and reduced tissue damage in human cortical organoids and the embryonic brain of the ZIKV-induced mouse microcephaly model. Our findings highlight the protective role of CH25H during ZIKV infection and the potential use of 25HC as a natural antiviral agent to combat ZIKV infection and prevent ZIKV-associated outcomes, such as microcephaly.
Display omitted
•CH25H and its enzymatic product, 25HC, inhibit ZIKV entry in vitro•25HC attenuates ZIKV-associated viremia and disease in mice and non-human primates•25HC prevents ZIKV infection in human cortical organoids•25HC protects fetal mice from microcephaly caused by ZIKV infection
Zika virus (ZIKV) presents a major challenge to the global health system. Li et al. find that 25-hydroxycholesterol (25HC) inhibits ZIKV infection in monkeys and human cortical organoids and protects mice from microcephaly. 25HC has potential as a first-line antiviral agent to combat a broad array of pathogenic species, including ZIKV.
An intelligent human–machine interface (HMI) is a crucial medium for exchanging information between people and electronics. As one of the most important HMI devices, touch screen sensors are widely ...applied in personal electronics in daily life. However, as the most commonly used touch screen sensor, capacitive sensors can only detect limited kinds of gestures such as touching and sliding. Here, a triboelectric touch‐free screen sensor (TSS) is reported for recognizing diverse gestures in a noncontact operating mode by utilizing the charges naturally carried on the human body. Compared with conventional capacitive sensors, the TSS is capable of detecting various gestures such as the drop and lift of finger with different speeds, making a fist, opening palm, and flipping palm with different directions. Based on the TSS, an intelligent noncontact screen control system is further developed, which is used to unlock the smartphone interface by the noncontact operating mode. This research for the first time proposes the concept that taking the human body itself to participate in triboelectric self‐powered noncontact sensing and provides a touch‐free design concept to develop the next generation of screen sensors. It can alter the usual way that people operating their personal electronics.
A triboelectric touch‐free screen sensor (TSS) for recognizing diverse gestures is successfully demonstrated. Based on the TSS, an intelligent noncontact screen control system is further developed, which realizes the unlocking of a smartphone interface via the noncontact operating mode. This TSS with the noncontact gesture sensing method could make a remarkable breakthrough in establishing intelligent human–machine interactions.
Zika virus (ZIKV) was once considered an obscure member of the large and diverse family of mosquito-borne flaviviruses, and human infections with ZIKV were thought to be sporadic, with mild and ...self-limiting symptoms. The large-scale ZIKV epidemics in the Americas and the unexpected uncovering of a link to congenital birth defects escalated ZIKV infections to the status of a global public health emergency. Recent studies that combined reverse genetics with modelling in multiple systems have provided evidence that ZIKV has acquired additional amino acid substitutions at the same time as congenital Zika syndrome and other birth defects were detected. In this Progress article, we summarize the evolution of ZIKV during its spread from Asia to the Americas and discuss potential links to pathogenesis.
Abstract
With the rise of network technology, the Internet has been integrated into all aspects of people’s life, which brings convenience to our daily life. However, the rise of the network has led ...to the emergence of a large number of web pages, which also makes it difficult for people to accurately need the information. At the same time, the proliferation of Internet users leads to a large number of user behavior data, which has been applied to analyze user behavior. By mining Web log information, we can extract the behavior rules and interests of users, which will put forward more decision direction. By improving the system platform, we can improve better user service, which will improve the user experience. Facing the marine user behavior generated by web, we can analyze it by clustering algorithm, which will better analyze the compliance detection of user behavior. Through user behavior clustering, we can extract the user’s browsing behavior in the web server log, which will better mine the user’s interest.
Zika virus (ZIKV) has evolved into a global health threat because of its unexpected causal link to microcephaly. Phylogenetic analysis reveals that contemporary epidemic strains have accumulated ...multiple substitutions from their Asian ancestor. Here we show that a single serine-to-asparagine substitution Ser139→Asn139 (S139N) in the viral polyprotein substantially increased ZIKV infectivity in both human and mouse neural progenitor cells (NPCs) and led to more severe microcephaly in the mouse fetus, as well as higher mortality rates in neonatal mice. Evolutionary analysis indicates that the S139N substitution arose before the 2013 outbreak in French Polynesia and has been stably maintained during subsequent spread to the Americas. This functional adaption makes ZIKV more virulent to human NPCs, thus contributing to the increased incidence of microcephaly in recent ZIKV epidemics.
China has lost 50% of its mangroves since the 1950s, while the remaining mangroves are exhibiting an increase in fragmentation. While a detailed mangrove map of China derived from remote sensing ...imagery is crucial for protecting mangroves, fragmented mangrove patches are hardly captured by Landsat-derived 30-m-resolution maps. To overcome this limitation, we proposed 10-m-resolution mangrove maps for 2017 using Sentinel SAR and optical time-series imagery, together with terrain data. We first classified coastal land covers based on quantile synthesis; following this, the mangrove category was refined by applying the tidal flat constraint and manual editing. The proposed approach considered factors that limit the accuracy of mangrove maps, including tidal inundation, intertidal terrain, cloudiness, and phenological variations of vegetation. A pixel-based mangrove map (PXL_Map) and an object-based mangrove map (OBJ_Map) were produced using the Google Earth Engine cloud computing platform. PXL_Map achieved an overall accuracy of 95.3 ± 0.2% based on validation samples, and a 91.6% accuracy based on field sample plots. OBJ_Map had a slightly lower performance than PXL_Map. The maps produced in this study improved the delineation of small mangrove patches along tidal creeks relative to recent Landsat-based maps. The total mangrove area was estimated to be between 21,148 ha (by PXL_Map) and 24,801 ha (by OBJ_Map). Furthermore, the spatial differences among the mangrove maps produced in this study were quantitatively compared with three other existing mangrove maps. The discrepancies among maps could have been due to the size and the location of the mangrove patches. The 10-m-resolution mangrove maps from this study can help manage and protect mangroves in China, especially the small fragmented mangrove patches scattered along the coast.
Zika virus (ZIKV) remained obscure until the recent explosive outbreaks in French Polynesia (2013-2014) and South America (2015-2016). Phylogenetic studies have shown that ZIKV has evolved into ...African and Asian lineages. The Asian lineage of ZIKV was responsible for the recent epidemics in the Americas. However, the underlying mechanisms through which ZIKV rapidly and explosively spread from Asia to the Americas are unclear. Non-structural protein 1 (NS1) facilitates flavivirus acquisition by mosquitoes from an infected mammalian host and subsequently enhances viral prevalence in mosquitoes. Here we show that NS1 antigenaemia determines ZIKV infectivity in its mosquito vector Aedes aegypti, which acquires ZIKV via a blood meal. Clinical isolates from the most recent outbreak in the Americas were much more infectious in mosquitoes than the FSS13025 strain, which was isolated in Cambodia in 2010. Further analyses showed that these epidemic strains have higher NS1 antigenaemia than the FSS13025 strain because of an alanine-to-valine amino acid substitution at residue 188 in NS1. ZIKV infectivity was enhanced by this amino acid substitution in the ZIKV FSS13025 strain in mosquitoes that acquired ZIKV from a viraemic C57BL/6 mouse deficient in type I and II interferon (IFN) receptors (AG6 mouse). Our results reveal that ZIKV evolved to acquire a spontaneous mutation in its NS1 protein, resulting in increased NS1 antigenaemia. Enhancement of NS1 antigenaemia in infected hosts promotes ZIKV infectivity and prevalence in mosquitoes, which could have facilitated transmission during recent ZIKV epidemics.
Mobile edge computing (MEC) providing information technology and cloud-computing capabilities within the radio access network is an emerging technique in fifth-generation networks. MEC can extend the ...computational capacity of smart mobile devices (SMDs) and economize SMDs' energy consumption by migrating the computation-intensive task to the MEC server. In this paper, we consider a multi-mobile-users MEC system, where multiple SMDs ask for computation offloading to a MEC server. In order to minimize the energy consumption on SMDs, we jointly optimize the offloading selection, radio resource allocation, and computational resource allocation coordinately. We formulate the energy consumption minimization problem as a mixed interger nonlinear programming (MINLP) problem, which is subject to specific application latency constraints. In order to solve the problem, we propose a reformulation-linearization-technique-based Branch-and-Bound (RLTBB) method, which can obtain the optimal result or a suboptimal result by setting the solving accuracy. Considering the complexity of RTLBB cannot be guaranteed, we further design a Gini coefficient-based greedy heuristic (GCGH) to solve the MINLP problem in polynomial complexity by degrading the MINLP problem into the convex problem. Many simulation results demonstrate the energy saving enhancements of RLTBB and GCGH.
PDF
