Bio-based coated fertilizers are promising alternatives to conventional chemical fertilizers due to their excellent performances. Identifying key influencing factors and deciphering controlled release mechanism are essential for their development. Kinetic modeling is a powerful tool for elucidating the complex mechanism governing nutrient release. However, a significant technical bottleneck lies in the gap between idealized laboratory evaluations and practical field performance. Herein, controlled release mechanism of starch-based polyurethane coated urea (BPCU), was elucidated based on the synergistic effect of coating materials and environmental factors. Nutrient release behaviors of BPCU were investigated under different temperatures and soil moisture contents. Structural changes of BPCU coating at various release stages were analyzed by using techniques such as SEM in detail, and release kinetics were evaluated using four classical models. It was found that temperature was the key factor affecting its nutrient release, and higher temperature favored the swelling rate resulting in a rapid nutrient release and the shortening release longevity. SEM and CT results indicated that the expansion of the bio-based coating in water increased the volume and number of micropores. Furthermore, the BPCU release process exhibited two kinetic patterns, namely, polymer swelling and relaxation conforming to non-Fickian diffusion in the first half and non-swelling diffusion belonging to Fickian diffusion in the second half. A release kinetics prediction model was proposed, with an average relative error of 14.5%. This study narrows the gap between laboratory evaluation and practical field application, providing support for the development of bio-based coated fertilizers.
Polymer coated fertilizers (PCFs) play a crucial role in the sustainable development of precision agriculture. However, conventional petroleum-based coating materials for PCFs are non-degradable and depend on non-renewable resources. Thus, biobased coatings, particularly those derived from vegetable oils, are promising alternatives. This review presents an innovative classification of vegetable oils based on their chemical structure, specifically whether they contain natural hydroxyl groups or require hydroxylation modification. By leveraging data from the Web of Science database, we systematically analyze the research progress of vegetable oil-based polyurethane coated urea from 2005 to 2024. Hydroxyl modification strategies for vegetable oils lacking natural hydroxyl groups are explored. Preparation processes and controlled-release properties of polyurethane coated urea made from both types of vegetable oils are included. Furthermore, aiming at potential coating defects, various modification strategies and their practical effects are evaluated in detail. These insights provide a systematic reference for raw material selection and formulation optimization of vegetable oil-based coated urea. While summarizing the key research achievements, this review comprehensively describes the future challenges faced by the practical application of vegetable oil-based polyurethanes in this field, and proposes potential breakthrough paths based on material innovation and process optimization.
: CRISPR/Cas12a-based combinational screening has shown remarkable potential for identifying genetic interactions. Here, we describe an innovative method for combinational genetic screening with rapid construction of a dual-CRISPR RNA (crRNA) library using gene splicing through overlap extension PCR (SOE PCR) and the adoption of CeCas12a, which we previously identified with strict PAM recognition and low off-targeting to guarantee fidelity and efficiency. The custom-pooled SOE crRNA array (SOCA) library for double-knockout screening could be conveniently constructed in the laboratory for widespread use, and the CeCas12a-mediated high-fidelity screen displayed good performance even under a negative selection screen. By designing a SOCA dual-crRNA library that covered most of the kinase and metabolism-associated gene targets of FDA-approved drugs implicated in hepatocellular carcinoma (HCC) tumourigenesis, novel cross-talk between the two gene sets was negatively selected to inhibit HCC cell growth in vitro and in vivo and was validated using virtual double-knockdown screening based on TCGA databases. Thus, this rapid, efficient and high-fidelity double-knockout screening system is promising for systemically identifying potential genetic interactions between multiple gene sets or combinations of FDA- approved drugs for clinical translational medicine in the future.
Vegetable-oil-based polyurethane has become a promising sustainable candidate for controlled-release fertilizer based on green chemistry. The purpose of this study was to prepare a series of coatings from selective feedstocks including five vegetable oils with a high saturation degree, mono-unsaturation degree, or poly-unsaturation degree, considering that vegetable oil fatty acids played a key role in the synthesis of polyol and polyurethane. The effect of the type and proportion of fatty acids on the physicochemical properties, microstructure, and macro-properties of vegetable-oil-derived polyols and their resulting coatings was characterized and discussed. The position and number of the hydroxy groups were determined by the type and proportion of fatty acid, and polyol from linseed oil with a high poly-unsaturation degree and three carbon–carbon double bonds had a high hydroxyl value and functionality, whereas polyol from palm oil with a high saturation degree possessed the lowest hydroxyl value and functionality. The resultant coating from linseed-oil-based polyol had a good cross-linking density, and the nitrogen release longevity of coated urea was 56 days at a coating percentage of 3%, and its nitrogen use efficiency was increased by 27.15% compared with conventional urea. Although the palm-oil-based coating had good hydrophobicity, its coated urea was not ideal. Overall, this study has enriched theories of bio-based polyurethane coatings for controlled-release fertilizers; using vegetable oil with a poly-unsaturation degree, it is easy to obtain an excellent coating for controlled-release fertilizer, and this will help provide economic and environmental benefits.
Sustainable polyurethane coated fertilizer is attracting much attention. Reducing the amount of curing agent is promising to improve the bio-content and biodegradability of coating material. In order to achieve the aim, the research attempted to select palm oil with balanced unsaturation as feedstock, hydrochloric acid as both catalyst and nucleophilic reagent for bio-polyols with low hydroxyl values by the epoxidation/ring-opening reaction. The chemical structures of palm oil-based polyols and properties of polyurethanes were tailored by controlling hydrochloric acid amount, and the effect was investigated by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), etc. With the increase of hydrochloric acid amount, hydroxyl value, functionality and viscosity of palm oil-based polyol were gradually increased. The resultant coatings prepared by the palm oil-based polyol with hydroxyl value exceeding 120 mg KOH g-1 and functionality of more than 2 had good macroscopic performances including controlled nutrient release property as a result of high crosslinking density. The optimum amount was 10%, for the viscosity of the relative palm oil-based polyol was beneficial to the coating process. The bio-content of the coating was 67% and the nitrogen release duration of the coated urea was 73 days at the coating rate of 7% even without paraffin. Overall, the way offers a bio-based platform to create a variety of polyurethane coated fertilizer that promises economic and environmental benefits.
To manufacture high bio-content degradable polyurethane-coated fertilizer, the co-liquefaction of corn straw and starch was carried out to convert more biomass into bio-polyol so as to substitute petroleum-based polyol. The effect of the corn straw to starch ratio on liquefaction behavior was mainly investigated by monitoring acid value, hydroxyl value, and liquefaction rate. Both chemical structures and properties of bio-polyols and their coatings were characterized by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), etc. The results indicated that adding a certain amount of starch to corn straw for co-liquefaction could contribute to a higher hydroxyl content of bio-polyol than that from sole biomass. Compared to molecular weight, the hydroxyl value was a more significant index to ensure coating quality. The incorporation of starch segments to bio-polyol led to good thermal stability, limited residual small molecules, and high crosslinking density of the coating. The controlled-release ability of coated urea prepared by co-liquefied bio-polyol was better than that of corn-straw-based bio-polyol, and the optimal ratio of corn straw to starch was 3:1. Overall, this study provides a new route to fabricate corn straw as a cost-effective and degradable coating with good controlled-release properties, which benefits solid biomass recycling.
A new route, introducing POSS-OH to liquefaction of biomass, is developed for bio-based polyurethane nano-composites and applied in the controlled release of chemicals. The effect of POSS-OH on the chemical structures and properties of biopolyols and their coatings was characterized by GC-MS, FTIR and others. The results indicated that after adding POSS-OH to liquefaction of starch, the hydroxyl content of the biopolyol synthesized was higher than that of the biopolyol from sole starch, and the resultant nanocomposite owned good thermal stability, water resistance and, importantly, non-toxicity to plants. Meanwhile, after coating the urea granules, the controlled release ability of the nanocomposite coating with 3% POSS-OH was the best, and in comparison with the coating without POSS-OH the nitrogen release duration was prolonged by a month. Overall, POSS-OH was used not only as both co-liquefier of biomass instead of the commonly used glycerol to affect the liquefaction process, but also as filler for bio-based polyurethane nanocomposite to improve the interaction. Thus, the sub-stitution of petroleum-based polyols can be expected in synthesizing the green and bio-based coatings for controlled release of chemicals.
Improved degradation performance of bio-based polyurethane coatings has become a significant challenge for agricultural applications of controlled-release fertilizers. In this work, petroleum-based isocyanate components were innovatively replaced with lysine diisocyanate (LDI) ingredients in various ratios by the in-situ reaction with castor oil to synthesize high bio-based content polyurethane coating materials. The chemical structure and properties of the coatings were also investigated to propose the mechanism of LDI-mediated coatings controlled release and degradation performance. The experiment results indicate that as the LDI content increased, the coatings’ thermodynamic stability, cross-linking density, and controlled release performance decreased while their hydrophilicity and degradation performance increased. Compared to other coated ureas, the coated urea with the 1:1 replacement ratio of petroleum-based isocyanate performed well and had adjustable controlled release performance. Its release period was regulated by adjusting the coating rate and reached 60 days with the 3 % coating rate. With the increase of the lysine component, the degradation performance of the coating materials was improved till the replacing ratio of petroleum-based isocyanate was higher than 1:1. In all, the introduction of bio-based isocyanate is an alternative way further to enhance the degradation performance of the coating materials, and the coatings were non-toxic to rice seeds. The coordination of the controlled release and degradation performance of the coatings can be achieved by adjusting the content of LDI. This research designed a novel strategy to solve the bottleneck problem of bio-based polyurethane coating degradation in coated fertilizers.
缓控释肥料是采用物理、化学或物理化学的方法对速效性化肥进行改性,从而实现养分缓慢释放或控制释放的新型肥料,不仅能满足植物整个生长期的养分需求,还可以提高肥料利用率、降低环境风险,是农业绿色发展的重要保障.纳米材料具有尺寸小、表面积大以及界面效应显著等特性,其在缓控释肥中的应用已成为当前缓控释肥料领域的研究热点.本文分别综述了纳米氧化物、纳米纤维素、纳米碳和纳米粘土等主要纳米材料在缓控释肥中的添加技术和应用效果.物理共混、化学接枝、浸渍吸附等是纳米材料改性缓控释肥的常用技术手段,纳米材料发挥的最重要功能是疏水性、吸附性、保水性、环境响应性和自修复性.纳米材料表面丰富的官能团、物理交联点或微纳米凸起的形成等是提高缓控释效果的关键因素.拓展天然有机纳米材料、探寻简单高效的改性方法、明确相应缓控释肥的养分释放及性能调控机制是今后研究的重要方向.
Bio-based polyurethane (PU)-coated controlled release fertilizers are attracting a lot of attention; however, generally they have poor properties, so it is difficult for them to meet the agricultural needs. Herein, γ-aminopropyl triethoxy silane (KH550) was first used with nanosilica (NS) to prepare bio-based PU nanocomposite-coated urea (KSPCU). The coating microstructures and nutrient controlled release behaviors of KSPCU were investigated and compared with those of unmodified NS containing PU nanocomposite-coated urea (SPCU) and bio-based PU-coated urea (PCU). The KSPCU with KH550 exhibited an excellent controlled release performance. Its nutrient release longevity exceeded 105 d, which was nearly 6 times greater than that of PCU and 2 times more than that of SPCU, and it was much longer than that of PCU reported in previous research at a coating rate of 3 wt %. A series of characterization methods combined with water resistance capacity and porosity measurements confirmed that a hydrogen bond was formed by the reaction between the nanoparticle and PM200, the nanoparticle was bonded on the macromolecular chain, and KH550 in the coating increased the cross-linking degree, which were beneficial to slowing down the nutrient release of the KSPCU. The innovative application of KH550 on bio-based PU-coated fertilizers will provide a new coating technology for improving their controlled release property.
BACKGROUND Hypertension is a growing problem worldwide and can often result in a variety of negative health outcomes. The aim of this study was to assess the effects of age at diagnosis, calendar period, and birth cohort on the change in the prevalence rate of hypertension in Guangzhou from 2004 to 2013. METHODS We used data from the Guangzhou Community Health Survey, a population-based study designed by the National Health and Family Planning Commission of the PRC every 5 years. A total of 27,299, 23,467, and 18,362 participants aged 15-79 years completed the survey in 2004, 2009, and 2013, respectively. RESULTS Age effects increased slowly before the age of 42 years but increased rapidly after the age of 42 years, peaking at 79 years. Cohort effects grew slowly before the end of the 1960s but grew quickly after the end of the 1960s. The risk of suffering from hypertension among people born in 1962, 1972, 1982, and 1992 was 1.39, 2.68, 5.55, and 11.53 times, respectively, than that of people born in 1952. The period effects increased 25% from 2004 to 2009 and later declined 27% from 2009 to 2013 in the entire population. There was no gender difference in age effects and period effects, but strong cohort effects on hypertension were observed among males compared with females. CONCLUSIONS For Chinese individuals, the later one is born, the higher the risk is of suffering from hypertension. Strong cohort effects for hypertension were observed among males compared with females, indicating that males are more easily affected by hypertension based on the change in birth cohort.
HIV-related discrimination amongst healthcare providers is one of the strongest obstacles to effectively responding to HIV. This study was conducted to explore the occurrence of and other factors related to discrimination against people living with HIV/AIDS amongst healthcare providers in Guangzhou, China.
Background: We aimed to describe the trends and associated factors of hypertension among residents aged ≥15 yr in Guangzhou, China. Methods: Three standardized cross-sectional health surveys were conducted in 2004, 2009 and 2013 using a multi-stage cluster sampling method, and a total of 69128 qualified participants were included in the study. The data were obtained through physical health examination and questionnaire survey. Results: The age-standardised prevalence of hypertension increased from 12.5% to 16.0% between 2004 and 2009 and declined from 16.0% to 14.0% between 2009 and 2013, and crude prevalence respectively was 14.6%, 19.1% and 18.8% in 2004, 2009 and 2013. The proportion of optimal blood pressure dropped from 51.1% to 33.2%, high-normal blood pressure increased from 20.1% to 28.9%, grade 1 hypertension and grade 2 or 3 hypertension increased from 11.5% to 13.6% and 3.9% to 5.8% between 2004 and 2013. The average age was significantly increased (P<0.001) from 42.8 to 47.5 yr, and the average body mass index slightly increased (P<0.001) from 22.4 to 23.0. Logistic regression analysis shows that higher age, male, higher body mass index, smoking and drinking alcohol were potential risk factors for hypertension. Conclusion: Both crude and age-standardized prevalence of hypertension were initially increased, but subsequently decreased in Guangzhou during 2004–2013. The optimal blood pressure population decreased significantly while the high-normal blood pressure population increased substantially during the survey period.
Exercise induces the expression of peroxisome proliferator-activated receptor gamma co-activator 1-α (PGC-1α) in skeletal muscle, which promotes the cleavage of fibronectin type III domain-containing protein 5 (FNDC5) to irisin. To explore the relationship between irisin and its regulators, we analyzed the plasma irisin levels and the muscle levels of FNDC5 and PGC-1α after exercise. Male C57BL/6J mice underwent a treadmill exercise (60% of VO2max) for 30 min or one hour (h), and blood and gastrocnemius samples were collected before exercise (pre-exercise), immediately after exercise, and during 24-h recovery after 1-h exercise. We found that plasma irisin levels were significantly increased during exercise (P < 0.05), while FNDC5 protein levels were not significantly increased. Moreover, PGC-1α mRNA and protein levels were significantly increased during 30-min exercise, but were decreased during 1-h exercise. After 1-h exercise, the irisin levels peaked at 6 h (20.71 ± 0.25 ng/ml) and decreased to pre-exercise levels by 24 h (15.45 ± 0.27 ng/ml). Likewise, PGC-1α mRNA and protein levels were increased at 1 h and maintained at elevated levels for 6 h; thereafter, the expression levels of PGC1-α protein were decreased to pre-exercise levels at 12 h. Thus, the restoration of PGC-1α expression to the pre-exercise levels was followed by the decrease in plasma irisin levels. By contrast, during 24-h recovery, the expression levels of FNDC5 mRNA and protein were maintained at elevated levels. These results suggest that the coordinated expression of FNDC5 and PGC-1α may contribute to the increased levels of plasma irisin after exercise.
BACKGROUND:Acute T-lymphocyte leukaemia is a form of haematological malignancy with abnormal activation of NF-κB pathway, which results in high expression of A20 and ABIN1, which constitute a negative feedback mechanism for the regulation of NF-κB activation. Clinical studies have found that acute T-lymphocyte leukaemia patients are susceptible to Toxoplasma gondii infection; however, the effect of T. gondii on the proliferation and apoptosis of human leukaemia T-cells remains unclear. Here, we used the T. gondii ME-49 strain to infect human leukaemia T-cell lines Jurkat and Molt-4, to explore the effect of T. gondii on proliferation and apoptosis, which is mediated by NF-κB in human leukaemia T-cells.METHODS:The Tunel assay was used to detect cell apoptosis. Cell Counting Kit-8 was used to detect cell proliferation viability. The apoptosis level and the expression level of NF-κB related proteins in human leukaemia T-cells were detected by flow cytometry and Western blotting.RESULTS:Western blotting analyses revealed that the T. gondii ME-49 strain increased the expression of A20 and decreased both ABIN1 expression and NF-κB p65 phosphorylation. By constructing a lentiviral-mediated shRNA to knockdown the A20 gene in Jurkat T-cells and Molt-4 T-cells, the apoptosis levels of the two cell lines decreased after T. gondii ME-49 infection, and levels of NF-κB p65 phosphorylation and ABIN1 were higher than in the non-konckdown group. After knockingdown ABIN1 gene expression by constructing the lentiviral-mediated shRNA and transfecting the recombinant expression plasmid containing the ABIN1 gene into two cell lines, apoptosis levels and cleaved caspase-8 expression increased or decreased in response to T. gondii ME-49 infection, respectively.CONCLUSIONS:Our data suggest that ABIN1 protects human leukaemia T-cells by allowing them to resist the apoptosis induced by T. gondii ME-49 and that the T. gondii ME-49 strain induces the apoptosis of human leukaemia T-cells via A20-mediated downregulation of ABIN1 expression.
The percentages of low birth weight (LBW) increased from 7.7% in 2005 to 11.3% in 2011 and declined to 8.1% in 2017. For very low birth weight (VLBW) individuals, the proportion declined -1.0% annually, from 2.5% in 2005 to 1.4% in 2017. Among moderately low birth weight (MLBW) individuals, the proportion first increased 12.8% annually, from 5.0% in 2005 to 9.3% in 2011, and then declined -3.8% annually, from 9.4% in 2011 to 7.0% in 2017. The percentages of macrosomia monotone decreased from 4.0% in 2005 to 2.5% in 2017, an annual decline of -4.0%. Multiple regression analyses showed that boys, maternal age, hypertensive disorders complicating pregnancy (HDCP), and diabetes were significant risk factors for LBW. Boys, maternal age, gestational age, HDCP, diabetes, and maternal BMI were significant risk factors for macrosomia. Although the relevant figures declined slightly in our study, it is likely that LBW and macrosomia will remain a major public health issue over the next few years in China. More research aimed at control and prevention of these risk factors for LBW and macrosomia and their detrimental outcome in the mother and perinatal child should be performed in China.
People living with HIV or AIDS (PLWHA) experienced severe medical discrimination which is seriously affecting their lives. However, few studies examined the epidemic characteristics of self-perceived medical discrimination from the discrimination objects such as PLWHA. Therefore, we aimed to investigate the epidemiological status and analyze the influential factors of the self-perceived medical discrimination on PLWHA in South China. The self-designed questionnaire was used to investigate the medical discrimination status of the 443 infected persons, who were randomly recruited from the representative AIDS designated hospitals in Guangdong Province in South China. The results showed that 49.0% of PLWHA experienced medical discrimination, and 55.3% received discriminatory treatment, 48.4% experienced refusal of treatment, 36.4% had private information leaked and 12.9% received mandatory test. However, 52.2% patients chose to endure discrimination in silence. Compared with the Asymptomatic HIV-infected patients, AIDS patients perceived more medical discrimination. The Logistic regression analysis indicated that PLWHA self-perceived medical discrimination status was influenced by 4 factors: the voluntary of first medical detection, the route of transmission, the stage of the disease and the familiarity with the HIV/AIDS-related law. Additionally, the two dimensions of the life quality scale were influenced by medical discrimination, namely, overall function and disclosure worry. Ultimately, our study provides a better understanding of the relationship between infection status, quality of life and the medical discrimination they experienced or perceived. It will help health professionals and policy makers to develop tailored behavioral and policy-oriented intervention strategies for PLWHA to tackle different types of medical discrimination in high-risk settings.
Objectives Cyberbullying research in China is in early stage. This study describes the cyberbullying experiences of junior and senior high school students in Guangzhou, China, and to examine the risk factors associated with cyberbullying perpetrators, victims and perpetrator-victims among students. We also investigated the frequency of cyberbullying and coping strategies of student victims. Methods Participants were 2590 students in grades 7, 8, 9 and 10 from six junior and senior high schools in October 2015 in Guangzhou, in south China, who completed a questionnaire. Data on participants' experiences with cyberbullying perpetration and victimisation during the previous 6months were collected. Multinomial logistic regression was used to analyse factors associated with being perpetrators, victims and perpetrator-victims. Results In this sample, 28.0% (725) of participants reported being a perpetrator and 44.5% (1150) reported being a victim in the previous 6months. Specifically, 2.9% (74) reported being perpetrators only, 19.3% (499) reported being victims only and 25.2% (651) reported being perpetrator-victims (both perpetrator and victim). In addition, flaming was the most common form of cyberbullying in both perpetration and victimisation. Logistic regression analyses indicated that online game addiction in participants was associated with increased odds of being a perpetrator only; no democratic parenting style in the mother and physical discipline by parents were associated with increased odds of being a victim only; male students, students with low academic achievement, those spending over 2hours a day online, experiencing physical discipline from parents and online game addiction were associated with increased odds of both perpetration and victimisation. Conclusions Cyberbullying is a common experience among Chinese junior and senior high school students. These findings add to the empirical data on cyberbullying and reinforce the urgent need for cyberbullying prevention in China. Furthermore, from the perspective of practice, it is important to raise our awareness of cyerbullying and reduce the risk factors.