Abstract
Background
Coronavirus disease 2019 (COVID-19) is a global pandemic with no licensed vaccine or specific antiviral agents for therapy. Little is known about the longitudinal dynamics of ...severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–specific neutralizing antibodies (NAbs) in patients with COVID-19.
Methods
Blood samples (n = 173) were collected from 30 patients with COVID-19 over a 3-month period after symptom onset and analyzed for SARS-CoV-2–specific NAbs using the lentiviral pseudotype assay, coincident with the levels of IgG and proinflammatory cytokines.
Results
SARS-CoV-2–specific NAb titers were low for the first 7–10 days after symptom onset and increased after 2–3 weeks. The median peak time for NAbs was 33 days (interquartile range IQR, 24–59 days) after symptom onset. NAb titers in 93.3% (28/30) of the patients declined gradually over the 3-month study period, with a median decrease of 34.8% (IQR, 19.6–42.4%). NAb titers increased over time in parallel with the rise in immunoglobulin G (IgG) antibody levels, correlating well at week 3 (r = 0.41, P < .05). The NAb titers also demonstrated a significant positive correlation with levels of plasma proinflammatory cytokines, including stem cell factor (SCF), TNF-related apoptosis-inducing ligand (TRAIL), and macrophage colony-stimulating factor (M-CSF).
Conclusions
These data provide useful information regarding dynamic changes in NAbs in patients with COVID-19 during the acute and convalescent phases.
•Production of ethanol and galactonic acid from CWP was fully investigated.•Glucose was fermented to ethanol to clear the path for galactonic acid production.•110 g ethanol and 305 g galactonic acid ...could be produced from 1 kg CWP.•Two-step bioprocess provides an alternative method for the bioremediation of CWP.
Cheese whey, produced from coagulation of milk during cheese manufacture, is a major environmental pollutant. The most abundant component in cheese whey is lactose, which is a potential resource for various value-added chemicals. Here, a two-step bioprocess using Saccharomyces cerevisiae and Gluconobacter oxydans to bioconvert cheese whey into ethanol and galactonic acid was first proposed. First, the lactose in cheese whey powder was pretreated with β-galactosidase to obtain glucose and galactose. Subsequently, the glucose was selectively fermented to ethanol by S. cerevisiae to enable G. oxydans-mediated biooxidation of galactose to galactonic acid. Finally, approximately 110 g ethanol, 320 g galactonate, and 150 g mixed protein (residual cheese whey protein and cell protein) was produced from 1 kg CWP. These results are suggestive of alternative methods for management of cheese whey, which may reduce its impact on the environment and result in production of value-added biochemicals.
High‐performance and novel graphene‐based electrothermal films are fabricated through a simple yet versatile solution process. Their electrothermal performances are studied in terms of applied ...voltage, heating rate, and input power density. The electrothermal films annealed at high temperature show high transmittance and display good heating performance. For example, the graphene‐based film annealed at 800 °C, which shows transmittance of over 80% at 550 nm, can reach a saturated temperature of up to 42 °C when 60 V is applied for 2 min. Graphene‐based films annealed at 900 and 1000 °C can exhibit high steady‐state temperatures of 150 and 206 °C under an applied voltage of 60 V with a maximum heating rate of over 7 °C s−1. For flexible heating films patterned on polyimide, a steady‐state temperature of 72 °C could be reached in less than 10 s with a maximum heating rate exceeding 16 °C s−1 at 60 V. These excellent results, combined with the high chemical stability and mechanical flexibility of graphene, indicate that graphene‐based electrothermal elements hold great promise for many practical applications, such as defrosting and antifogging devices.
Transparent and flexible graphene electrothermal films are prepared on different substrates such as quartz and polyimide. These films show high electrothermal performances and several potential applications are proposed.
A series of inkjet printing processes have been studied using graphene-based inks. Under optimized conditions, using water-soluble single-layered graphene oxide （GO） and few-layered graphene oxide ...（FGO）, various high image quality patterns could be printed on diverse flexible substrates, including paper, poly（ethylene terephthalate） （PET） and polyimide （PI）, with a simple and low-cost inkjet printing technique. The graphene-based patterns printed on plastic substrates demonstrated a high electrical conductivity after thermal reduction, and more importantly, they retained the same conductivity over severe bending cycles. Accordingly, flexible electric circuits and a hydrogen peroxide chemical sensor were fabricated and showed excellent performances, demonstrating the applications of this simple and practical inkjet printing technique using graphene inks. The results show that graphene materials--which can be easily produced on a large scale and possess outstanding electronic properties--have great potential for the convenient fabrication of flexible and low-cost graphene- based electronic devices, by using a simple inkjet printing technique.
•GDP has increased much faster than GPI in Chinese megacities in recent decades.•Chinese cities have improved human welfare greatly at the expense of environment.•Western Chinese cities lag in ...development and have smaller ecological footprints.•Eastern Chinese cities are challenged by more and greater environmental problems.•Chinese megacities are faced with increasing problems of socioeconomic inequality.
Driven by unprecedented economic development for more than three decades, China's urbanization level rose from 17.9% in 1978 to 54.8% in 2014. This breakneck speed of urbanization has resulted in myriad environmental problems and social inequities. To gauge the urban sustainability of China, our study focused on ten megacities which are socioeconomic centers of the country. We evaluated the three dimensions of sustainability using a set of sustainability indicators, including Genuine Progress Indicator (GPI), Ecological Footprint (EF), Biocapacity, Environmental Performance Index (EPI), City Development Index (CDI), Human Development Index (HDI), Gini coefficient, and Urban–rural income ratio. Based on time-series data from 1978 to 2012, our study has produced the following findings: (1) The values of GPI for the ten megacities started to increase since 2006 after a relatively constant period between 1994 and 2005; (2) The pressures of economic growth on the environment (EF) increased while biocapacity decreased for the ten megacities, with smaller biocapacity deficits for western cities; (3) The overall level of human wellbeing (HDI) increased; (4) Socioeconomic inequality (Gini and urban–rural income ratio) widened, but the widening trend seemed to have ceased in recent years for most of the ten megacities; and (5) Certain aspects of urban environment and city development (EPI and CDI) improved gradually, particularly in waste treatment and infrastructure development. Our findings suggest that, to achieve overall urban sustainability, China must move away from maximizing economic development and focus on improving environmental quality of its megacities.
Dissecting the in vivo host-pathogen interplay is crucial to understanding the molecular mechanisms governing control or progression of intracellular infections. In this work, we explore the in vivo ...molecular dynamics of Mtb infection by performing dual RNA-seq on Mycobacterium tuberculosis-infected, ontogenetically distinct macrophage lineages isolated directly from murine lungs. We first define an in vivo signature of 180 genes specifically upregulated by Mtb in mouse lung macrophages, then we uncover a divergent transcriptional response of the bacteria between alveolar macrophages that appear to sustain Mtb growth through increased access to iron and fatty acids and interstitial macrophages that restrict Mtb growth through iron sequestration and higher levels of nitric oxide. We use an enrichment protocol for bacterial transcripts, which enables us to probe Mtb physiology at the host cell level in an in vivo environment, with broader application in understanding the infection dynamics of intracellular pathogens in general.
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•Dual RNA-seq analysis of M. tuberculosis infected macrophages•Infected macrophages were isolated directly from mouse lung•Transcriptional signatures of host and pathogen varied with macrophage ontogeny•Data highlighted a key role for nutritional immunity in limiting bacterial growth
In this study Pisu et al. performed dual RNA-seq on Mycobacterium tuberculosis-infected, ontogenetically distinct macrophage lineages isolated directly from infected murine lungs. The transcriptional response of host and bacteria diverged between alveolar macrophages that sustain Mtb growth and interstitial macrophages that restrict Mtb growth.
Herein, the cross‐linking density was adjusted controllably by tuning the curing reaction to gain polydimethylsiloxane (PDMS) elastomers with different mechanical performances. First of all, the ...cross‐linking network of PDMS was adjusted by tuning the parameters of the fabrication process such as curing temperature, curing time, and component ratio. Lowering the temperature, shortening the curing time, and using less curing agent were discovered to effectively reduce the cross‐linking density. Then, the effects of important factors on cross‐linking density, including the fabrication process, the time for post‐curing, and the content of carbon nanotube (CNT), were thoroughly discussed. Furthermore, the dynamic mechanical performance, mechanical characteristics, and viscoelastic properties of PDMS and PDMS/CNT composites were studied based on the regulation of the cross‐linking network. The stronger the cross‐linking density, the higher the storage modulus, the greater the restriction on the molecular chain of silicone rubber. Besides, the post‐curing for 5 months and the introduction of CNT fillers appeared to be a viable option for promoting the cross‐linking reaction with higher density and thereby strengthening the mechanical properties of PDMS.
Cross‐linking density was adjusted controllably by tuning the curing conditions, post‐curing and the addition of CNT fillers.
•Optimal combination of spectrum transformation and model were selected for different heavy metal.•Results showed that the accuracy of RF was higher than that of SVM and PLS.•This study can provide ...technical support for the nondestructive monitoring of soil heavy metal content.
Hyperspectral remote sensing technology has considerable research value in monitoring and evaluating soil heavy metal pollution. In this study, the Three-River Source Region was taken as the study area. The occurrence relationship of six heavy metals in soil, such as Mn, Cu, Zn, Pb, Cr, Ni, with soil organic matter, clay minerals, and iron-manganese oxides, was studied through the determination and analysis of soil samples and the collection of soil reflectance spectrum. Spectral transformation was carried out by first derivative, second derivative, inverse-log, continuum removal and multiple scattering correction of the spectrum. The correlation between soil heavy metal content and soil spectrum was analyzed to select the characteristic band, and partial least squares (PLS) method, support vector machine (SVM) method and random forest (RF) model were used to build inversion model based on characteristic band. Then the best combination of spectral transformation and inversion model were explored. The results showed that Pb contents were the twice of the background in Qinghai province. The combination spectrum processing method can improve the correlation between spectrum and heavy metals. The location and quantity of characteristic bands of six heavy metals are different. The accuracy of RF was significantly better than that of SVM and PLS for all six heavy metal (i.e. pb: R2RF = 0.83, R2SVM = 0.62, R2PLS = 0.18), and the model effective of soil properties in non-polluted sites were reliable (i.e. clay: R2RF = 0.93, R2SVM = 0.87, R2PLS = 0.74). This study can provide technical support for the larger-scale monitoring of soil heavy metal content and heavy metal pollution assessment.
•• The green economic efficiency (GEE) is measured through a super-efficient SBM model.•• The digital economy development level is calculated by principal component analysis.•• The digital economy ...has a positive effect on urban GEE.•• Mechanisms base on marketization, industry, innovation and energy are detected.•• The effects vary between different urban location, scale and environmental regulation intensity.
The development of the digital economy has changed human lifestyles and production and provided a new approach to achieving the United Nations Sustainable Development Goals (SDGs). As an important indicator reflecting both economic growth and ecological protection, the green economic efficiency (GEE) indicator is employed to express the level of sustainable development. By building an indicator system, introducing carbon dioxide emissions as an unexpected output and using a super-efficient slack-based measure (SBM) model, the the GEE of 273 cities in China are calculated. The development level of digital economy is calculated through principal component analysis (PCA). Unlike previous provincial-level studies, this study focuses on analyzing at the urban level. This study then uses a fixed effect model to analyze the effect of the digital economy on urban GEE. Based on various aspects, the transmission mechanisms of the digital economy on GEE have also been deeply analyzed. The results indicate that the digital economy has a positive effect on GEE. This conclusion is validated by endogeneity analysis and other robustness tests. The digital economy has a positive influence on urban GEE in Eastern, Central and Northeastern China. In large cities, medium-sized cities and cities with stricter governmental environmental regulations, the effect of the digital economy on GEE is more prominent. The mechanism analysis indicates that the digital economy mainly promotes urban GEE through the technological innovation effect, industrial structure optimization, energy structure transformation and market-oriented development. This study clarifies the role of the digital economy in advancing GEE and provides a reference to promote ecological development in developing countries.
Secure data transmission is a critical issue for wireless sensor networks (WSNs). Clustering is an effective and practical way to enhance the system performance of WSNs. In this paper, we study a ...secure data transmission for cluster-based WSNs (CWSNs), where the clusters are formed dynamically and periodically. We propose two secure and efficient data transmission (SET) protocols for CWSNs, called SET-IBS and SET-IBOOS, by using the identity-based digital signature (IBS) scheme and the identity-based online/offline digital signature (IBOOS) scheme, respectively. In SET-IBS, security relies on the hardness of the Diffie-Hellman problem in the pairing domain. SET-IBOOS further reduces the computational overhead for protocol security, which is crucial for WSNs, while its security relies on the hardness of the discrete logarithm problem. We show the feasibility of the SET-IBS and SET-IBOOS protocols with respect to the security requirements and security analysis against various attacks. The calculations and simulations are provided to illustrate the efficiency of the proposed protocols. The results show that the proposed protocols have better performance than the existing secure protocols for CWSNs, in terms of security overhead and energy consumption.
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