The rapid outbreak of coronavirus disease 2019 (COVID-19) has been a matter of international concern as the disease is spreading fast 1, 2. Considering that the contagious disease has led to an ...enormous impact globally, there is an urgent need to identify the risk populations with poor prognosis. Ageing is associated with certain changes in pulmonary physiology, pathology and function, during the period of lung infection. Therefore, age-related differences in responsiveness and tolerance become obvious and lead to worse clinical outcomes in elderly individuals 3. Previous studies have mentioned that older COVID-19 patients are at an increased risk of death 4–7. However, the age-related clinical characteristics, disease courses and outcomes other than death in COVID-19 patients remain unclear.
Age significantly determined the clinical features and prognosis of COVID-19. The prognosis was worse in patients older than 60 years, calling for clinicians to pay more attention to patients of this age.
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A patient's infectivity is determined by the presence of the virus in different body fluids, secretions, and excreta. The persistence and clearance of viral RNA from different specimens of patients ...with 2019 novel coronavirus disease (COVID-19) remain unclear. This study analyzed the clearance time and factors influencing 2019 novel coronavirus (2019-nCoV) RNA in different samples from patients with COVID-19, providing further evidence to improve the management of patients during convalescence.
The clinical data and laboratory test results of convalescent patients with COVID-19 who were admitted to from January 20, 2020 to February 10, 2020 were collected retrospectively. The reverse transcription polymerase chain reaction (RT-PCR) results for patients' oropharyngeal swab, stool, urine, and serum samples were collected and analyzed. Convalescent patients refer to recovered non-febrile patients without respiratory symptoms who had two successive (minimum 24 h sampling interval) negative RT-PCR results for viral RNA from oropharyngeal swabs. The effects of cluster of differentiation 4 (CD4)+ T lymphocytes, inflammatory indicators, and glucocorticoid treatment on viral nucleic acid clearance were analyzed.
In the 292 confirmed cases, 66 patients recovered after treatment and were included in our study. In total, 28 (42.4%) women and 38 men (57.6%) with a median age of 44.0 (34.0-62.0) years were analyzed. After in-hospital treatment, patients' inflammatory indicators decreased with improved clinical condition. The median time from the onset of symptoms to first negative RT-PCR results for oropharyngeal swabs in convalescent patients was 9.5 (6.0-11.0) days. By February 10, 2020, 11 convalescent patients (16.7%) still tested positive for viral RNA from stool specimens and the other 55 patients' stool specimens were negative for 2019-nCoV following a median duration of 11.0 (9.0-16.0) days after symptom onset. Among these 55 patients, 43 had a longer duration until stool specimens were negative for viral RNA than for throat swabs, with a median delay of 2.0 (1.0-4.0) days. Results for only four (6.9%) urine samples were positive for viral nucleic acid out of 58 cases; viral RNA was still present in three patients' urine specimens after throat swabs were negative. Using a multiple linear regression model (F = 2.669, P = 0.044, and adjusted R = 0.122), the analysis showed that the CD4+ T lymphocyte count may help predict the duration of viral RNA detection in patients' stools (t = -2.699, P = 0.010). The duration of viral RNA detection from oropharyngeal swabs and fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group (15 days vs. 8.0 days, respectively; t = 2.550, P = 0.013) and the duration of viral RNA detection in fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group (20 days vs. 11 days, respectively; t = 4.631, P < 0.001). There was no statistically significant difference in inflammatory indicators between patients with positive fecal viral RNA test results and those with negative results (P > 0.05).
In brief, as the clearance of viral RNA in patients' stools was delayed compared to that in oropharyngeal swabs, it is important to identify viral RNA in feces during convalescence. Because of the delayed clearance of viral RNA in the glucocorticoid treatment group, glucocorticoids are not recommended in the treatment of COVID-19, especially for mild disease. The duration of RNA detection may relate to host cell immunity.
Highly selective and sensitive H2S sensors are in high demand in various fields closely related to human life. However, metal oxide semiconductors (MOSs) suffer from poor selectivity and single ...MOS@metal organic framework (MOF) core–shell nanocomposites are greatly limited due to the intrinsic low sensitivity of MOF shells. To simultaneously improve both selectivity and sensitivity, heterostructured α‐Fe2O3@ZnO@ZIF‐8 core–shell nanowires (NWs) are meticulously synthesized with the assistance of atomic layer deposition. The ZIF‐8 shell with regular pores and special surface functional groups is attractive for excellent selectivity and the heterostructured α‐Fe2O3@ZnO core with an additional electron depletion layer is promising with enhanced sensitivity compared to a single MOS core. As a result, the heterostructured α‐Fe2O3@ZnO@ZIF‐8 core–shell NWs achieve remarkable H2S sensing performance with a high response (Rair/Rgas = 32.2 to 10 ppm H2S), superior selectivity, fast response/recovery speed (18.0/31.8 s), excellent long‐term stability (at least over 3 months), and relatively low limit of detection (down to 200 ppb) at low operating temperature of 200 °C, far beyond α‐Fe2O3@ZIF‐8 or α‐Fe2O3@ZnO core–shell NWs. Furthermore, a micro‐electromechanical system‐based H2S gas sensor system with low power consumption is developed, holding great application potential in smart cities.
Heterostructured α‐Fe2O3@ZnO@ZIF‐8 core–shell nanowires are meticulously synthesized with the assistance of atomic layer deposition to simultaneously improve both selectivity and sensitivity as gas sensors. As a result, remarkable ppb‐level H2S sensing performance is achieved. Furthermore, a micro‐electromechanical system‐based H2S gas sensor system with low power consumption is developed, holding great application potential in smart cities.
A pandemic of severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) infection broke out all over the world; however, epidemiological data and viral shedding in pediatric patients are limited. ...We conducted a retrospective, multicenter study, and followed‐up with all children from the families with SARS‐CoV‐2 infected members in Zhejiang Province, China. All infections were confirmed by testing the SARS‐CoV‐2 RNA with real‐time reverse transcription PCR method, and epidemiological data between children and adults in the same families were compared. Effect of antiviral therapy was evaluated observationally and fecal‐viral excretion times among groups with different antiviral regiments were compared with Kaplan‐Meier plot. By 29 February 2020, 1298 cases from 883 families were confirmed with SARS‐CoV‐2 infection and 314 of which were families with children. Incidence of infection in child close contacts was significantly lower than that in adult contacts (13.2% vs 21.2%). The mean age of 43 pediatric cases was 8.2 years and mean incubation period was 9.1 days. Forty (93.0%) were family clustering. Thirty‐three children had coronavirus disease 2019 (20 pneumonia) with mild symptoms and 10 were asymptomatic. Fecal SARS‐CoV‐2 RNA detection was positive in 91.4% (32/35) cases and some children had viral excretion time over 70 days. Viral clearance time was not different among the groups treated with different antiviral regiments. No subsequent infection was observed in family contacts of fecal‐viral‐excreting children. Children have lower susceptibility of SARS‐CoV‐2 infection, longer incubation, and fecal‐viral excretion time. Positive results of fecal SARS‐CoV‐2 RNA detection were not used as indication for hospitalization or quarantine.
Highlights
Children had lower susceptibility for SARS‐CoV‐2 infection than adults.
Children had longer incubation period and fecal viral excretion time after infected by SARS‐CoV‐2.
Viral clearance time was not different among the groups treated with different antiviral regiments.
Children had milder clinical symptoms, better clinical outcome, and more common fecal viral excretion.
Positive results of fecal SARS‐CoV‐2 RNA detection are not used as indication for hospitalization or quarantine.
Abstract
Phosphorus (P) is an essential macronutrient for plant growth and development. Low inorganic phosphate (Pi) availability is a limiting factor for plant growth and yield. To cope with a ...complex and changing environment, plants have evolved elaborate mechanisms for regulating Pi uptake and use. Recently, the molecular mechanisms of plant Pi signaling have become clearer. Plants absorb Pi from the soil through their roots and transfer Pi to various organs or tissues through phosphate transporters, which are precisely controlled at the transcript and protein levels. Here, we summarize recent progress on the molecular regulatory mechanism of phosphate transporters in Arabidopsis and rice, including the characterization of functional transporters, regulation of transcript levels, protein localization and turnover of phosphate transporters. A more in-depth understanding of plant adaptation to a changing Pi environment will facilitate the genetic improvement of plant P efficiency.
Highlights
Recent progress in noble metal-decorated (NM-D) semiconducting metal oxides (SMOs) gas sensors are summarized.
Gas sensing mechanisms related to noble metal decoration are carefully ...discussed.
Crucial challenges facing the development of NM-D SMOs gas sensors are analyzed.
Highly sensitive gas sensors with remarkably low detection limits are attractive for diverse practical application fields including real-time environmental monitoring, exhaled breath diagnosis, and food freshness analysis. Among various chemiresistive sensing materials, noble metal-decorated semiconducting metal oxides (SMOs) have currently aroused extensive attention by virtue of the unique electronic and catalytic properties of noble metals. This review highlights the research progress on the designs and applications of different noble metal-decorated SMOs with diverse nanostructures (e.g., nanoparticles, nanowires, nanorods, nanosheets, nanoflowers, and microspheres) for high-performance gas sensors with higher response, faster response/recovery speed, lower operating temperature, and ultra-low detection limits. The key topics include Pt, Pd, Au, other noble metals (e.g., Ag, Ru, and Rh
.
), and bimetals-decorated SMOs containing ZnO, SnO
2
, WO
3
, other SMOs (e.g., In
2
O
3
, Fe
2
O
3
, and CuO), and heterostructured SMOs. In addition to conventional devices, the innovative applications like photo-assisted room temperature gas sensors and mechanically flexible smart wearable devices are also discussed. Moreover, the relevant mechanisms for the sensing performance improvement caused by noble metal decoration, including the electronic sensitization effect and the chemical sensitization effect, have also been summarized in detail. Finally, major challenges and future perspectives towards noble metal-decorated SMOs-based chemiresistive gas sensors are proposed.
The first case of 2009 pandemic influenza A (H1N1) infection in China was identified on May 10, 2009. An initial policy of quarantine was instituted, and the early cases were systematically ...monitored. In these early 426 cases, the incubation period (2 days), spectrum of illness (67.4% with fever), and duration of viral shedding by PCR (6 days) were determined.
In China an initial policy of quarantine was instituted and early cases of H1N1 were systematically monitored. In these early cases, the incubation period was 2 days, 67.4% of the patients had fever, and the duration of viral shedding was 6 days.
In early April 2009, cases of human infection with 2009 pandemic influenza A (H1N1) virus were identified in the United States
1
,
2
and Mexico,
3
and the virus then spread rapidly to other regions of the world.
4
,
5
The 2009 H1N1 virus is a triple-reassortant influenza virus containing genes from human, swine, and avian influenza viruses.
6
–
8
After documentation of human-to-human transmission of the virus in at least three countries in two of the six world regions defined by the World Health Organization (WHO), the WHO raised the pandemic level from 5 to 6, the highest level.
9
The first three cases . . .
Nanoscale titanium nitride TiN is a metallic material that can effectively harvest sunlight over a broad spectral range and produce high local temperatures via the photothermal effect. Nanoscale ...indium oxide‐hydroxide, In2O3−x(OH)y, is a semiconducting material capable of photocatalyzing the hydrogenation of gaseous CO2; however, its wide electronic bandgap limits its absorption of photons to the ultraviolet region of the solar spectrum. Herein, the benefits of both nanomaterials in a ternary heterostructure: TiN@TiO2@In2O3−x(OH)y are combined. This heterostructured material synergistically couples the metallic TiN and semiconducting In2O3−x(OH)y phases via an interfacial semiconducting TiO2 layer, allowing it to drive the light‐assisted reverse water gas shift reaction at a conversion rate greatly surpassing that of its individual components or any binary combinations thereof.
TiN@TiO2@In2O3−x(OH)y combines the benefits of surface plasmon and photothermal effect of TiN, interfacial charge transfer TiO2 layer, and photocatalyzing In2O3−x(OH)y. The choice and precise arrangement of three components allow for a controlled flow of photogenerated electrons and phonons that drives CO2 hydrogenation reaction at an elevated rate which excels its individual and binary components.
Heterostructured α-Fe2O3/SnO2 core-shell nanowires (NWs) are successfully synthesized assisted with atomic layer deposition (ALD). The gas sensing properties of α-Fe2O3/SnO2 core-shell NWs with ...various shell thicknesses in the range of 5–28 nm are investigated. The gas sensing mechanism is fully analyzed based on both the widely accepted electron depletion model and the Debye length concept. When the shell thickness reaches ∼18 nm, the sensor of the heterostructured α-Fe2O3/SnO2 core-shell NWs exhibit high responses (Ra/Rg) of 4.3 towards 10 ppm and 1.5 towards 1 ppm H2S at 250 °C, excellent selectivity, remarkable repeatability, and long-term stability of at least 3 months, which completely exceed that of pristine α-Fe2O3 NWs. The formation of α-Fe2O3/SnO2 heterojunction contributes to the effectively enhanced performance, which is further investigated and confirmed by density functional theory calculations. In addition, the sensors are fabricated based on specially designed MEMS sensing devices, providing excellent heating conditions for sensitive nanomaterials with the merits of low power consumption and high integration.
•Heterostructured α-Fe2O3/SnO2 core-shell NWs with precisely controlled shell thickness were prepared by ALD.•The SnO2 shell thickness had a critical effect on the gas sensing properties of the α-Fe2O3/SnO2 NWs sensors.•The well-designed MEMS-based sensor exhibited superior H2S sensing with low power consumption.
We study the holographic dual of the two-dimensional non-relativistic field theory with anisotropic scaling from a symmetry perspective. We construct a new four-dimensional metric with ...two-dimensional global anisotropic scaling isometry. The four-dimensional spacetime is homogeneous and is a solution of Einstein gravity with quadratic-curvature extension. We consider this spacetime dual to the vacuum of the boundary field theory. By introducing a proper solution phase space, we find that the asymptotic symmetry of the gravity theory is the two-dimensional local anisotropic conformal symmetry, which recovers precisely the results from the dual non-relativistic field theory side.
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