To determine distribution of severe acute respiratory syndrome coronavirus 2 in hospital wards in Wuhan, China, we tested air and surface samples. Contamination was greater in intensive care units ...than general wards. Virus was widely distributed on floors, computer mice, trash cans, and sickbed handrails and was detected in air ≈4 m from patients.
Hydrothermal carbonization (HTC) is a thermochemical conversion technique which is attractive due to its ability to transform wet biomass into energy and chemicals without predrying. The solid ...product, known as hydrochar, has received attention because of its ability to prepare precursors of activated carbon in wastewater pollution remediation, soil remediation applications, solid fuels, and other carbonaceous materials. Besides the generally lignocellulose biomass used as sustainable feedstock, HTC has been applied to a wide range of derived waste, including sewage sludge, algae, and municipal solid waste to solve practical problems and generate desirable carbonaceous products. This review presented the critical hydrothermal parameters of HTC, including temperature, residence time, heating rate, reactant concentration, and aqueous quality. The chemical reaction mechanisms involved in the formation of hydrochar derived from single components and representative feedstock, lignocellulose, and sludge termed as N-free and N-rich biomass, were elucidated and summarized to better understand the hydrochar formation process. Specifically, hydrochar physicochemical characteristics such as surface chemistry and structure were investigated. Current knowledge gaps, and new perspectives with corresponding recommendations were provided to further exploit the great potential of the HTC technique and more practical applications for hydrochar in the future.
•Hydrothermal carbonization of biomass waste receives great deal attention.•Hydrothermal conditions during HTC process are critical to hydrochar production.•The chemical reaction mechanisms involved in hydrochar formation are reviewed.•Hydrochar physicochemical characteristics from biomass waste are summarized.
SnSe with 3D hierarchical nanostructure composed of interconnected single‐crystal SnSe nanosheets is synthesized via a fast and effective strategy. Unexpectedly, when used as the anode material for ...Na‐ion batteries (NIBs), the SnSe exhibits a high capacity (738 mA h g−1), superior rate capability (40 A g−1), and high energy density in a full cell. These results provide the possibility of SnSe use as NIBs anodes.
There was much evidence suggesting that the serum lactate dehydrogenase (LDH) levels reflect the extent of various pathophysiological processes. However, the current information about dynamic change ...of LDH in COVID-19 pneumonia has not been well investigated.
Study was performed in 87 cases confirmed by COVID-19 infection. The serum LDH levels were determined at diagnosis and follow-up visits. The evaluation of clinical response to therapy was based on chest CT scan. We selected the value of LDH around the data of chest CT scan (- 1 ~ + 1 day).
At diagnosis, significant differences in LDH levels were found between non-severe and severe group (P < 0.05). It was demonstrated that increase or decrease of LDH was indicative of radiographic progress or improvement (P < 0.05). The time to LDH normalization (5.67 ± 0.55, days) was positively correlated with the time to radiographic absorption (5.57 ± 0.65 days, r = 0.53, P < 0.05). Applying the cut-off value of the increase in LDH has good specificity to predict disease progression.
Serum LDH was validated for its potential usefulness as markers for evaluating clinical severity and monitoring treatment response in COVID-19 pneumonia.
A comprehensive study was conducted on the properties of chars which derived from hydrothermal carbonization (HTC) of sewage sludge (SS) while varying the operation parameters as reaction temperature ...180–300°C, reaction time 30–480min. The properties of chars derived from municipal sewage sludge HTC were evaluated by Elemental analysis, FTIR spectra and thermogravimetric analysis. Elemental analysis showed that O/C and H/C atomic ratios reduce to 0.07 and 1.84, respectively at 300°C, 30min due to dehydration and decarboxylation reactions were significant during HTC process. Higher heating values of the chars have improved 1.02–1.10 times of SS (10.97MJ/kg) when reaction temperature rose to 260°C with holding time between 30min and 90min. The approximate equilibrium moisture content becomes stable at 48.5% after 60min reaction. The FTIR spectra determined that the HTC reaction improved dehydration on the OH band in SS. Higher temperature improved carbon aromaticity during HTC of SS. The thermogravimetric analysis is an effective means to analyze combustion behavior and thermal characteristics. It was also used to determine combustion kinetics of SS and chars. The result shows that the ignition temperature of chars was higher and has better performance on safe handling, storing and transportation than SS.
The increase in childhood obesity is a serious public health concern. Several studies have indicated that breastfed children have a lower risk of childhood obesity than those who were not breastfed, ...while other studies have provided conflicting evidence. The objective of this meta-analysis was to investigate the association between breastfeeding and the risk of childhood obesity.
The PubMed, EMBASE and CINAHL Plus with Full Text databases were systematically searched from start date to 1st August 2014. Based on the meta-analysis, pooled adjusted odds ratio (AOR) and 95% confidence interval (CI) were calculated. I2 statistic was used to evaluate the between-study heterogeneity. Funnel plots and Fail-safe N were used to assess publication bias and reliability of results, and results from both Egger test and Begg test were reported.
Twenty-five studies with a total of 226,508 participants were included in this meta-analysis. The studies' publication dates ranged from 1997 to 2014, and they examined the population of 12 countries. Results showed that breastfeeding was associated with a significantly reduced risk of obesity in children (AOR = 0.78; 95% CI: 0.74, 0.81). Categorical analysis of 17 studies revealed a dose-response effect between breastfeeding duration and reduced risk of childhood obesity.
Results of our meta-analysis suggest that breastfeeding is a significant protective factor against obesity in children.
To recycle rusty stainless‐steel meshes (RSSM) and meet the urgent requirement of developing high‐performance cathodes for potassium‐ion batteries (KIB), we demonstrate a new strategy to fabricate ...flexible binder‐free KIB electrodes via transformation of the corrosion layer of RSSM into compact stack‐layers of Prussian blue (PB) nanocubes (PB@SSM). When further coated with reduced graphite oxide (RGO) to enhance electric conductivity and structural stability, the low‐cost, stable, and binder‐free RGO@PB@SSM cathode exhibits excellent electrochemical performances for KIB, including high capacity (96.8 mAh g−1), high discharge voltage (3.3 V), high rate capability (1000 mA g−1; 42 % capacity retention), and outstanding cycle stability (305 cycles; 75.1 % capacity retention).
Turning waste into treasure: Rusty stainless steel meshes were utilized as solid‐state iron sources with excellent conductivity properties in order to fabricate stable, low‐cost, and flexible binder‐free potassium‐ion battery electrodes. When combined with unique structural design, the reduced graphite oxide‐coated electrodes exhibited high capacities, superior rate capabilities, and excellent cycle performance.
An attractive method to response the current energy crisis and produce sustainable nonpolluting power source is harvesting energy from our living environment. However, the energy in our living ...environment always exists in low-frequency form, which is very difficult to be utilized directly. Here, we demonstrated a novel sandwich-shape triboelectric nanogenerator to convert low-frequency mechanical energy to electric energy with double frequency. An aluminum film was placed between two polydimethylsiloxane (PDMS) membranes to realize frequency multiplication by twice contact electrifications within one cycle of external force. The working mechanism was studied by finite element simulation. Additionally, the well-designed micro/nano dual-scale structures (i.e., pyramids and V-shape grooves) fabricated atop PDMS surface was employed to enhance the device performance. The output peak voltage, current density, and energy volume density achieved 465 V, 13.4 μA/cm2, and 53.4 mW/cm3, respectively. This novel nanogenerator was systematically investigated and also demonstrated as a reliable power source, which can be directly used to not only lighten five commercial light-emitting diodes (LEDs) but also drive an implantable 3-D microelectrode array for neural prosthesis without any energy storage unit or rectification circuit. This is the first demonstration of the nanogenerator for directly driving biomedical microsystems, which extends the application fields of the nanogenerator and drives it closer to practical applications.
This article considers the exponential stabilization and H∞ performance for delay reaction‐diffusion systems (DRDSs), with spatial sampled‐data controller (SSDC) and spatio‐temporal sampled‐data ...controller (STSDC). Firstly, an SSDC is designed to stabilize the DRDSs. Using Lyapunov functional and Wirtinger's inequality technique, we obtain sufficient conditions to ensure the exponential stability of DRDSs. When there exist external disturbances, H∞ performance is considered and criteria are provided for the disturbed DRDSs, under the designed SSDC. Then, an STSDC is adopted for DRDSs. Time discrete item brings new difficulties for the analysis of the desired properties. To overcome these difficulties, a novel Lyapunov functional is constructed and Halaney's inequality is used. Moreover, the descriptor method is adopted. Under these techniques, delay‐dependent conditions are obtained to guarantee the exponential stability. The H∞ performance is also considered for the disturbed DRDSs under the designed STSDC. A Razumikhin‐type method is introduced together with the Lyapunov‐like functional. Sufficient conditions are presented to achieve H∞ performance for DRDSs with STSDC. Our theoretical results show that the spatial sampling interval does affect the desired properties, the shorter the spatial sampling interval, the easier to achieve the desired properties. Moreover, the time delay also influences the exponential stability of DRDSs, and smaller time delay is beneficial to the achievement of the stability. Finally, examples are given to illustrate the validity of results.
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