One-step method to prepare starch-based superabsorbent polymer for slow release of fertilizer

Here we report the use of a one-step process of reactive melt mixing to prepare starch-based superabsorbent polymers (SBSAPs) for the slow release of urea as a fertilizer. A modified twin-rotor mixer, with improved sealing to establish an oxygen-free environment, was used to study the chemical and physical reactions during the melt-processing through monitoring the temperature and torque. The effects of the initiator (ceric ammonium nitrate, or CAN), crosslinker (N,N′-methylene-bisacrylamide, or N,N′-MBA) and saponification agent (NaOH) under different reaction conditions (time, temperature, and shear intensity) were systematically studied. Also investigated was the effect of starch with different amylose content. Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) confirmed that using this simple technique, SBSAPs were successfully prepared from either high-amylopectin starch (waxy corn starch) or high-amylose starch (Gelose 50) grafted with AM and crosslinked by N,N′-MBA. Gel strength was evaluated by rheometry, which revealed a significant increase in storage modulus (G′) obtained in the crosslinked high-amylose SBSAP gels. Also, scanning electron microscopy (SEM) images showed a more sophisticated structural network with a smaller pore size in the crosslinked high-amylose gels. Urea as a fertilizer was embedded in the SBSAP gel network, and this network controlled the urea release in water. The release rate of urea depended on the gel strength, gel microstructure and water absorption capacity (WAC) of SAP, which was affected by the reaction conditions and degree of saponification

The therapeutic prospects of N-acetylgalactosamine-siRNA conjugates

RNA interference has become increasingly used for genetic therapy following the rapid development of oligonucleotide drugs. Significant progress has been made in its delivery system and implementation in the treatment of target organs. After a brief introduction of RNA interference technology and siRNA, the efficiency and stability of GalNAc-siRNA conjugates are highlighted since several oligonucleotide drugs of GalNAc have been approved for clinical use in recent years. The structure and features of GalNAc-siRNA conjugates are studied and the clinical efficiency and limitations of oligonucleotide-based drugs are summarized and investigated. Furthermore, another delivery system, lipid nanoparticles, that confer many advantages, is concluded, includ-ing stability and mass production, compared with GalNAc-siRNA conjugates. Importantly, developing new approaches for the use of oligonucleotide drugs brings hope to genetic therapy

A Negative Feedback Loop in Ultraviolet A-Induced Senescence in Human Dermal Fibroblasts Formed by SPCA1 and MAPK

Secretory pathway calcium ATPase 1 (SPCA1) is a calcium pump localized specifically to the Golgi. Its effects on UVA-induced senescence have never been examined. In our study, expression of SPCA1 was increased in UVA-irradiated human dermal fibroblasts (HDFs) by activating mitogen-activated protein kinase (MAPK) and its downstream transcription factor, c-jun. Dual-luciferase reporter and chromatin immunoprecipitation assays revealed that c-jun regulated SPCA1 by binding to its promoter. Furthermore, downregulating SPCA1 with siRNA transfection aggravated UVA-induced senescence due to an elevation of intracellular calcium concentrations and a subsequent increase in reactive oxygen species (ROS) and MAPK activity. In contrast, overexpression of SPCA1 reduced calcium overload, consequently lowering the ROS level and suppressing MAPK activation. This alleviated the cellular senescence caused by UVA irradiation. These results indicated that SPCA1 might exert a protective effect on UVA-induced senescence in HDFs via forming a negative feedback loop. Specifically, activation of MAPK/c-jun triggered by UVA transcriptionally upregulated SPCA1. In turn, the increased SPCA1 lowered the intracellular Ca2+ level, probably through pumping Ca2+ into the Golgi, leading to a reduction of ROS, eventually decreasing MAPK activity and diminishing UVA-induced senescence

Ultrasound-Mediated DNA Transformation in Thermophilic Gram-Positive Anaerobes

Thermophilic, Gram-positive, anaerobic bacteria (TGPAs) are generally recalcitrant to chemical and electrotransformation due to their special cell-wall structure and the low intrinsic permeability of plasma membranes. transformants/µg of methylated DNA. Delivery into X514 cells was confirmed via detecting the kanamycin-resistance gene for pIKM2, while confirmation of pHL015 was detected by visualization of fluorescence signals of secondary host-cells following a plasmid-rescue experiment. Furthermore, the foreign β-1,4-glucanase gene was functionally expressed in X514, converting the host into a prototypic thermophilic consolidated bioprocessing organism that is not only ethanologenic but cellulolytic.In this study, we developed an ultrasound-based sonoporation method in TGPAs. This new DNA-delivery method could significantly improve the throughput in developing genetic systems for TGPAs, many of which are of industrial interest yet remain difficult to manipulate genetically

A rapid and simple single-step method for the purification of Toxoplasma gondii tachyzoites and bradyzoites

This study describes a simple method for the large-scale isolation of pure Toxoplasma gondii tachyzoites and bradyzoites. T. gondii tachyzoites were obtained from infected human foreskin fibroblasts (HFFs) and peritoneal exudates of mice, while tissue cysts containing bradyzoites were collected from chronically infected mice. Harvested cells and brain tissues were incubated in Hanks balanced salt solution (HBSS), containing 0.25% trypsin and 0.5% taurodeoxycholic acid (TDC) for 5 min. Subsequent washes in phosphate buffered saline (PBS) were conducted, and the cell viability of the preparations was good, as determined by flow cytometry and ability to reinfect HFF cells and propagate in mice. The purification procedure allowed for a rapid preparation of pure T. gondii tachyzoites and bradyzoites in sufficient quantity that can be used for downstream procedures. The advantage of the new method is that it is convenient and inexpensive.The National Natural Science Foundation of China (No. 31502071), Youth Innovative Talents Project of Guangdong province Education Department (No. 2017KQNCX212), Guangdong province (2017GDK07), Start-up Research Grant Program provided by Foshan University, Foshan city, Guangdong province for distinguished researchers, Guangdong Science and Technology Plan Project (Grant No: 1244060045607389XC), and School of Life Science and Engineering fund (Grant No: KLPREAD201801-02).http://www.wileyonlinelibrary.com/journal/vms3am2021Paraclinical Science

Ongoing progress in cleaning China′s air: A novel outlook into pollution

Over the past 30 years, particulate matter (PM) air pollution has progressively worsened in many of China′s urban and suburban areas. This review provides a current picture of the air pollution in China with an emphasis on the history of PM pollution, policies and reduction goals, recent improvements, and known adverse health effects of PM exposure. Several studies have provided the analyses of current PM pollution levels in cities across China using satellite data and air-monitoring stations. These analyses are consistent with the Chinese Ministry of Environmental Protection (MEP) 2015 air pollution report, which concluded that only 8 of 74 (10.8%) cities met the Chinese standards for safe annual average PM 2.5 exposure (35 μg/m 3 ). Even fewer cities met the World Health Organization PM 2.5 guideline of 10 μg/m 3 . The Government of China has acknowledged the public health threat of PM pollution and enacted higher standards and goals through the 12 th five-year plan (FYP) (2010), National Ambient Air Quality Standard (2012), the Air Pollution Prevention and Control Action Plan (2013), and the 13 th FYP (2016). A comparative analysis between 2010 and 2015 satellite data shows that PM pollution decreased by around 17% during this period. This improvement is corroborated by the MEP′s report on the State of the Environment in 2014 and the global burden of disease report in 2013. Despite these changes, PM pollution remains a substantial public health challenge. In 2010, an estimated 1.235 million deaths in China were attributed to PM air pollution. Long-term exposure to PM pollution increases the rates of cardiovascular, metabolic, and respiratory mortality. In particular, PM exposure increases the morbidity of respiratory illnesses such as chronic obstructive pulmonary disease (COPD), asthma, and lower respiratory infections (LRIs). Elevated levels of PM have been found to increase the incidence of all of the top five causes of death in 2012: Ischemic heart disease, stroke, COPD, LRI, and lung cancer. In addition, higher PM pollution decreases average birth weight, raises incidence of preterm birth, and increases the prevalence of Type II diabetes mellitus across the population. With the knowledge of these serious health consequences, China must enact greater measures to reduce dangerous PM levels

Polyethylene glycol (PEG) derived carbon dots: Preparation and applications

•The applications of polyethylene glycol (PEG) as passivation agents and solvents for carbon dots (C-dots) synthesis have been summarized.•The effects of PEG passivation on C-dots properties are carefully discussed.•The various synthesis methods and applications of PEG-derived C-dots are highlighted.•The reaction mechanism of PEG-derived C-dots and their indications on the general properties of C-dots are detailed.•Current challenges and future opportunities for PEG-derived C-dots are presented. Carbon dots (C-dots), the latest member of the renowned carbon nanomaterials family, have attracted enormous attention for their extraordinary properties. Polyethylene glycol (PEG), as a nontoxic, non-immunogenic and high water soluble polymer, is widely used for the PEGylation of protein/peptide drugs and traditional nanoparticles. Recently, PEG has been heavily investigated regarding their unique capability in enhancing C-dots fluorescence emission, elucidating C-dots formation and photoluminescence mechanism. In this article, we summarized recent excitements of PEGs as passivation agents, solvents/matrices and sole carbon precursors in the synthesis of C-dots. We also discussed the formation mechanism of PEG-derived C-dots as well as their applications in various fields. Current challenges, and perspectives on the future trends of PEG-derived C-dots are also highlighted and discussed. This review summarizes recent developments of polyethylene glycol (PEG) as passivation agent, solvent/matrix and carbon precursor for C-dots synthesis, as well as the applications of these PEG-derived C-dots in bioimaging, biosensing, biomedicine and catalysis. [Display omitted

Mobility patterns and associated factors among pregnant internal migrant women in China: a cross-sectional study from a National Monitoring Survey

Abstract Background Residential instability during pregnancy has been linked to poor health outcomes. As a first step toward providing better health care to pregnant migrant women, the size and characteristics of this population and factors associated with mobility during pregnancy should be studied. Methods Using the “Monitoring Data of Chinese Migrants” for 2012, from the Chinese National Population and Family Planning Commission, this study explored mobility patterns during pregnancy and associated factors among migrants within China. From a library of 158,556 participants, two subsamples were selected. Percentages, with chi-squared tests, and means and standard deviations, with ANOVAs, were adopted to describe mobility patterns during pregnancy (always staying in sending area, mainly staying in sending area, mainly staying in receiving area, and always staying in receiving area) and delivery location choice. Logistic regression analysis was used to explore the associated factors. Results We found that the percentage of migrants always or mainly staying in receiving areas during pregnancy rose from nearly 40% in 1985 to more than 80% in 2012, while the percentage of migrants who were mobile between receiving and sending areas during pregnancy fluctuated between 30 and 40% before 1995, and between 40 and 45% after 1995, decreasing to around 40% after 2008. The percentage of respondents who chose to deliver in receiving areas fluctuated but increased from 10% in 1985 to more than 50% in 2011. Among respondents who had delivered during the last year of the survey period, families with older pregnant women (OR = 1.09, 95% CI 1.05–1.13), their own housing (OR = 5.66, 95% CI 2.45–13.05), longer time in the receiving area (OR = 1.14, 95% CI 1.09–1.20), and strong will to integrate (OR = 1.32, 95% CI 1.15–1.51) always stayed in the receiving area during pregnancy, rather than the sending area, and families with broadly similar characteristics were inclined to choose the receiving area for their delivery. Conclusions The mobility patterns of pregnant migrant women in China have been changing in recent years, with the percentage of them staying in receiving areas during pregnancy and delivering there increasing. Individual and family characteristics were also associated with mobility patterns and delivery location choice

Learning discriminative spatiotemporal features for precise crop classification from multi-temporal satellite images

Precise crop classification from multi-temporal remote sensing images has important applications such as yield estimation and food transportation planning. However, the mainstream convolutional neural networks based on 2D convolution collapse the time series information. In this study, a 3D fully convolutional neural network (FCN) embedded with a global pooling module and channel attention modules is proposed to extract discriminative spatiotemporal presentations of different types of crops from multi-temporal high-resolution satellite images. Firstly, a novel 3D FCN structure is introduced to replace 2D FCNs as well as to improve current 3D convolutional neural networks (CNNs) by providing a mean to learn distinctive spatiotemporal representations of each crop type from the reshaped multi-temporal images. Secondly, to strengthen the learning significance of the spatiotemporal representations, our approach includes 3D channel attention modules, which regulate the between-channel consistency of the features from the encoder and the decoder, and a 3D global pooling module, which selects the most distinctive features at the top of the encoder. Experiments were conducted using two data sets with different types of crops and time spans. Our results show that our method outperformed in both accuracy and efficiency, several mainstream 2D FCNs as well as a recent 3D CNN designed for crop classification. The experimental data and source code are made openly available at http://study.rsgis.whu.edu.cn/pages/download/