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LiNO3 is recognized as an effective additive, forming a dense, nitrogen-rich solid electrolyte interphase (SEI) on lithium's surface, which safeguards it from parasitic reactions. However, its use is limited due to the poor solubility in carbonate electrolytes. Herein, we introduce a bilayer separator designed to release LiNO3 sustainably. This continual release not only alters the chemistry of the SEI but also replenishes the additives that are depleted during battery cycling, thereby enhancing the durability of the modified interphase. This strategy effectively curtails Li dendrite formation, significantly enhancing the longevity of Li|LiFePO4 batteries, evidenced by an impressive 85% capacity retention after 800 cycles. This research offers a compelling remedy to the longstanding challenge of incorporating LiNO3 in carbonate electrolytes.
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We aim to clarify the specific role of Karyopherin α2 (KPNA2) in the progression of laryngeal cancer, a kind of malignant tumor with a poor curative effect. We performed the bioinformatic analysis to obtain the ferroptosis-related differentially expressed genes. KPNA2 was screened out. Then the CCK-8 assay, wound healing assay, and transwell assay were used to clarify the changes in the proliferation, migration, and invasion abilities of laryngeal cancer cells after silencing KPNA2. The concentrations of iron ions, glutathione, superoxide dismutase, and malondialdehyde were evaluated by the corresponding detection kits. The expression levels of cyclooxygenase 2, Acyl-CoA synthetase long-chain family member 4, glutathione peroxidase 4, forkhead box O (FoxO)1a and FoxO3a were determined by Western Blot. A total of 45 ferroptosis-related differentially expressed genes in laryngeal cancer were obtained, and KPNA2 was selected after bioinformatic analysis. In ferroptosis-induced laryngeal cancer cells, the cell viability, migration rate, invasion ability, and the expression of glutathione peroxidase 4, glutathione, and superoxide dismutase were further decreased and the expression of cyclooxygenase 2, Acyl-CoA synthetase long-chain family member 4, iron ions, and malondialdehyde were further increased after silencing KPNA2. The expression levels of FoxO1a and FoxO3a in laryngeal cancer cells were increased by silencing KPNA2. KPNA2 may be a promising therapeutic target for laryngeal cancer. Down-regulation of KPNA2 can promote ferroptosis in laryngeal cancer by stimulating the FoxO signaling pathway.
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Constructing lithiophilic carbon hosts has been regarded as an effective strategy for inhibiting Li dendrite formation and mitigating the volume expansion of Li metal anodes. However, the limitation of lithiophilic carbon hosts by conventional surface decoration methods over long-term cycling hinders their practical application. In this work, a robust host composed of ultrafine MgF2 nanodots covalently bonded to honeycomb carbon nanofibers (MgF2/HCNFs) is created through an in situ solid-state reaction. The composite exhibits ultralight weight, excellent lithiophilicity, and structural stability, contributing to a significantly enhanced energy efficiency and lifespan of the battery. Specifically, the strong covalent bond not only prevents MgF2 nanodots from migrating and aggregating but also enhances the binding energy between Mg and Li during the molten Li infusion process. This allows for the effective and stable regulation of repeated Li plating/stripping. As a result, the MgF2/HCNF-Li electrode delivers a high Coulombic efficiency of 97% after 200 cycles, cycling stably for more than 2000 h. Furthermore, the full cells with a LiFePO4 cathode achieve a capacity retention of 85% after 500 cycles at 0.5C. This work provides a strategy to guide dendrite-free Li deposition patterns toward the development of high-performance Li metal batteries.
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Aluminum (Al) toxicity and low pH are major factors limiting plant growth in acidic soils. Sensitive to Proton Rhizotoxicity 1 (STOP1) transcription factors respond to these stresses by regulating the expression of multiple Al- or low pH-responsive genes. ZmSTOP1-A, a STOP1-like protein from maize (Zea mays), was localized to the nucleus and showed transactivation activity. ZmSTOP1-A was expressed moderately in both roots and shoots of maize seedlings, but was not induced by Al stress or low pH. Overexpression of ZmSTOP1-A in Arabidopsis Atstop1 mutant partially restored Al tolerance and improved low pH tolerance with respect to root growth. Regarding Al tolerance, ZmSTOP1-A/Atstop1 plants showed clear upregulation of organic acid transporter genes, leading to increased organic acid secretion and reduced Al accumulation in roots. In addition, the antioxidant enzyme activity in roots and shoots of ZmSTOP1-A/Atstop1 plants was significantly enhanced, ultimately alleviating Al toxicity via scavenging reactive oxygen species. Similarly, ZmSTOP1-A could directly activate ZmMATE1 expression in maize, positively correlated with the number of Al-responsive GGNVS cis-elements in the ZmMATE1 promoter. Our results reveal that ZmSTOP1-A is an important transcription factor conferring Al tolerance by enhancing organic acid secretion and reactive oxygen species scavenging in Arabidopsis.
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Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Aluminio/toxicidad , Aluminio/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
The high fidelity poses a central role in developing unnatural base pairs (UBPs), which means the high pairing capacity of unnatural bases with their partners, and low mispairing with all the natural bases. Different strategies have been used to develop higher-fidelity UBPs, including optimizing hydrophobic interaction forces between UBPs. Variant substituent groups are allowed to fine tune the hydrophobic forces of different UBPs' candidates. However, the modifications on the skeleton of TPT3 base are rare and the replication fidelity of TPT3-NaM remains hardly to improve so far. In this paper, we reasoned that modifying and/or expanding the aromatic surface by Bromo-substituents to slightly increase hydrophobicity of TPT3 might offer a way to increase the fidelity of this pair. Based on the hypothesis, we synthesized the bromine substituted TPT3, 2-bromo-TPT3 and 2, 4-dibromo-TPT3 as the new TPT3 analogs. While the enzyme reaction kinetic experiments showed that d2-bromo-TPT3-dNaM pair and d2, 4-dibromo-TPT3TP-dNaM pair had slightly less efficient incorporation and extension rates than that of dTPT3-dNaM pair, the assays did reveal that the mispairing of 2-bromo-TPT3 and 2, 4-dibromo-TPT3 with all the natural bases could dramatically decrease in contrast to TPT3. Their lower mispairing capacity promoted us to run polymerase chain amplification reactions, and a higher fidelity of d2-bromo-TPT3-dNaM pair could be obtained with 99.72 ± 0.01% of the in vitro replication fidelity than that of dTPT3-dNaM pair, 99.52 ± 0.09%. In addition, d2-bromo-TPT3-dNaM can also be effectively copied in E. coli cells, which showed the same replication fidelity as that of dTPT3-dNaM in the specific sequence, but a higher fidelity in the random sequence context.
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Emparejamiento Base , Bromo , Replicación del ADN , Humanos , Escherichia coli , CinéticaRESUMEN
Short-term high-concentration exposure to airborne fine particulate matter (PM2.5) is strongly associated with the risk of acute lung injury (ALI). It has been recently reported that exosomes (Exos) involve in the progression of respiratory diseases. However, the molecular mechanisms by which exosome-mediated intercellular signaling exacerbate PM2.5-induced ALI remains largely unaddressed. In the present study, we firstly investigated the effect of macrophage-derived exosomal tumor necrosis factor α (TNF-α) on pulmonary surfactant proteins (SPs) expression in epithelial MLE-12 cells after PM2.5 exposure. The higher levels of exosomes in the bronchoalveolar lavage fluid (BALF) of PM2.5-induced ALI mice were found. BALF-exosomes significantly up-regulated SPs expression in MLE-12 cells. Moreover, we found that remarkably high expression of TNF-α in exosomes secreted by PM2.5-treated RAW264.7 cells. Exosomal TNF-α promoted thyroid transcription factor-1 (TTF-1) activation and SPs expression in MLE-12 cells. Furthermore, intratracheal instillation of macrophage-derived TNF-α-containing exosomes increased epithelial cell SPs expression in the lungs of mice. Taken together, these results suggest that macrophages-secreted exosomal TNF-α can trigger epithelial cell SPs expression, which provides new insight and potential target in the mechanism of epithelial cell dysfunction in PM2.5-induced ALI.
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Lesión Pulmonar Aguda , Surfactantes Pulmonares , Animales , Ratones , Lesión Pulmonar Aguda/inducido químicamente , Lesión Pulmonar Aguda/metabolismo , Pulmón/metabolismo , Macrófagos/metabolismo , Material Particulado/toxicidad , Surfactantes Pulmonares/metabolismo , Surfactantes Pulmonares/toxicidad , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Objective: To develop the extreme gradient boosting (XG Boost) machine learning (ML) model for predicting gestational diabetes mellitus (GDM) compared with a model using the traditional logistic regression (LR) method. Methods: A case-control study was carried out among pregnant women, who were assigned to either the training set (these women were recruited from August 2019 to November 2019) or the testing set (these women were recruited in August 2020). We applied the XG Boost ML model approach to identify the best set of predictors out of a set of 33 variables. The performance of the prediction model was determined by using the area under the receiver operating characteristic (ROC) curve (AUC) to assess discrimination, and the Hosmer-Lemeshow (HL) test and calibration plots to assess calibration. Decision curve analysis (DCA) was introduced to evaluate the clinical use of each of the models. Results: A total of 735 and 190 pregnant women were included in the training and testing sets, respectively. The XG Boost ML model, which included 20 predictors, resulted in an AUC of 0.946 and yielded a predictive accuracy of 0.875, whereas the model using a traditional LR included four predictors and presented an AUC of 0.752 and yielded a predictive accuracy of 0.786. The HL test and calibration plots show that the two models have good calibration. DCA indicated that treating only those women whom the XG Boost ML model predicts are at risk of GDM confers a net benefit compared with treating all women or treating none. Conclusions: The established model using XG Boost ML showed better predictive ability than the traditional LR model in terms of discrimination. The calibration performance of both models was good.
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Diabetes Gestacional , Humanos , Femenino , Embarazo , Diabetes Gestacional/diagnóstico , Estudios de Casos y Controles , Algoritmos , Aprendizaje Automático , Modelos LogísticosRESUMEN
BACKGROUND: Airborne fine particulate matter with aerodynamic diameter ≤ 2.5 µm (PM2.5) pollution is associated with the prevalence of respiratory diseases, including asthma, bronchitis and chronic obstructive pulmonary disease. In patients with those diseases, circulating asymmetric dimethylarginine (ADMA) levels are increased, which contributes to airway nitric oxide deficiency, oxidative stress and inflammation. Overexpression of dimethylarginine dimethylaminohydrolase 1 (DDAH1), an enzyme degrading ADMA, exerts protective effects in animal models. However, the impact of DDAH1/ADMA on PM2.5-induced lung injury has not been investigated. METHODS: Ddah1-/- and DDAH1-transgenic mice, as well as their respective wild-type (WT) littermates, were exposed to either filtered air or airborne PM2.5 (mean daily concentration ~ 50 µg/m3) for 6 months through a whole-body exposure system. Mice were also acutely exposed to 10 mg/kg PM2.5 and/or exogenous ADMA (2 mg/kg) via intratracheal instillation every other day for 2 weeks. Inflammatory response, oxidative stress and related gene expressions in the lungs were examined. In addition, RAW264.7 cells were exposed to PM2.5 and/or ADMA and the changes in intracellular oxidative stress and inflammatory response were determined. RESULTS: Ddah1-/- mice developed more severe lung injury than WT mice after long-term PM2.5 exposure, which was associated with greater induction of pulmonary oxidative stress and inflammation. In the lungs of PM2.5-exposed mice, Ddah1 deficiency increased protein expression of p-p65, iNOS and Bax, and decreased protein expression of Bcl-2, SOD1 and peroxiredoxin 4. Conversely, DDAH1 overexpression significantly alleviated lung injury, attenuated pulmonary oxidative stress and inflammation, and exerted opposite effects on those proteins in PM2.5-exposed mice. In addition, exogenous ADMA administration could mimic the effect of Ddah1 deficiency on PM2.5-induced lung injury, oxidative stress and inflammation. In PM2.5-exposed macrophages, ADMA aggravated the inflammatory response and oxidative stress in an iNOS-dependent manner. CONCLUSION: Our data revealed that DDAH1 has a marked protective effect on long-term PM2.5 exposure-induced lung injury.
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Lesión Pulmonar , Óxido Nítrico , Amidohidrolasas , Animales , Inflamación/inducido químicamente , Lesión Pulmonar/inducido químicamente , Lesión Pulmonar/genética , Lesión Pulmonar/prevención & control , Ratones , Ratones Transgénicos , Óxido Nítrico/genética , Óxido Nítrico/metabolismo , Estrés Oxidativo , Material Particulado/toxicidad , Peroxirredoxinas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Transducción de Señal , Superóxido Dismutasa-1/metabolismo , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Developing host has been recognized a potential countermeasure to circumvent the intrinsic drawbacks of Li metal anode (LMA), such as uncontrolled dendrite growth, unstable solid electrolyte interface, and infinite volume fluctuations. To realize proper Li accommodation, particularly bottom-up deposition of Li metal, gradient designs of host materials including lithiophilicity and/or conductivity have attracted a great deal of attention in recent years. However, a critical and specialized review on this quickly evolving topic is still absent. In this review, we attempt to comprehensively summarize and update the related advances in guiding Li nucleation and deposition. First, the fundamentals regarding Li deposition are discussed, with particular attention to the gradient design principles of host materials. Correspondingly, the progress of creating different gradients in terms of lithiophilicity, conductivity, and their hybrid is systematically reviewed. Finally, future challenges and perspective on the gradient design of advanced hosts towards practical LMAs are provided, which would provide a useful guidance for future studies.
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Numerous epidemiological and experimental studies have demonstrated that the exposure to fine particulate matter (aerodynamic diameter <2.5 µm, PM2.5) was closely associated with cardiovascular morbidity and mortality. Our previous studies revealed that PM2.5 exposure induced cardiac dysfunction and fibrosis. However, the corresponding underlying mechanism remains largely unaddressed. Here, PM2.5-induced cardiotoxicity is presented to directly promote collagen deposition in cardiomyocytes through the transforming growth factor-ß (TGF-ß)-containing small extracellular vesicles (sEV). The sEV transition may play an important role in PM2.5-induced cardiac fibrosis. Firstly, long-term PM2.5 exposure can directly induce cardiac fibrosis and increase the level of serum sEV. Secondly, PM2.5 can directly activate macrophages and increase the release of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and TGF-ß-containing sEV. Thirdly, TGF-ß-containing sEV increases the expression of α-smooth muscle actin (α-SMA), collagen I, and collagen III in mouse cardiac muscle HL-1 cells. Finally, TGF-ß-containing sEV released from PM2.5-treated macrophages can increase collagen through the activation of the TGF-ß-Smad2/3 signaling pathway in HL-1 cells from which some fibroblasts involved in cardiac fibrosis are thought to originate. These findings suggest that TGF-ß-containing sEV from PM2.5-activated macrophages play a critical role in the process of increasing cardiac collagen content via activating the TGF-ß-Smad2/3 signaling pathway.
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Objective: Adolescents' alcohol consumption has lifetime adverse physical and mental health effects. Family environment factors have a significant influence in shaping adolescents' beliefs and habits. We conducted the multicenter cross-sectional study aiming to investigate the association between family environment factors and adolescent drinking behavior in China. Methods: The study investigated 27,762 middle school students from Beijing, Shanghai, Guangzhou, Jinan, Chengdu, and Harbin. A logistic regression model was used to explore the association between family environmental factors and adolescent drinking behavior. Participants were asked to self-report previous experiences of drinking and getting drunk to access their drinking status. Factors of family environment related to alcohol consumption included: parents' educational level, family economic status, family composition, the number of times parents drank alcohol in the past 30 days, and parents' attitudes toward their drinking behavior. The logistic regression model was used to adjust the demographic confounders, including gender, age, city, location, and smoking status, and to explore the association between family environmental factors and adolescent alcohol drinking behaviors. Results: Compared with students whose parents prohibited drinking, students who were approved drinking were more likely to drink in this year (OR = 16.544, 95%CI:15.265-17.929, P < 0.001; Full adjustment: OR = 13.111, 95% CI: 12.031-14.288, P < 0.001), drink in this month (OR = 7.791, 95% CI: 7.077-8.565, P < 0.001; Full adjustment: OR = 6.010, 95% CI: 5.439-6.641, P < 0.001). In addition, Low family economic status, not living with the mother, parents' ambivalent attitudes toward their children's drinking and parental drinking were risk factors for drinking among middle school students. Conclusion: The family environment, especially parents' attitudes, is associated with students' drinking and drunken behavior. Mobilizing the power of parents may play a positive role in the effective prevention and control of adolescent drinking.
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Fibrous material with high strength and large stretchability is an essential component of high-performance wearable electronic devices. Wearable electronic systems require a material that is strong to ensure durability and stability, and a wide range of strain to expand their applications. However, it is still challenging to manufacture fibrous materials with simultaneously high mechanical strength and the tensile property. Herein, the ultra-robust (≈17.6 MPa) and extensible (≈700%) conducting microfibers are developed and demonstrated their applications in fabricating fibrous mechanical sensors. The mechanical sensor shows high sensitivity in detecting strains that have high strain resolution and a large detection range (from 0.0075% to 400%) simultaneously. Moreover, low frequency vibrations between 0 and 40 Hz are also detected, which covers most tremors that occur in the human body. As a further step, a wearable and smart health-monitoring system has been developed using the fibrous mechanical sensor, which is capable of monitoring health-related physiological signals, including muscle movement, body tremor, wrist pulse, respiration, gesture, and six body postures to predict and diagnose diseases, which will promote the wearable telemedicine technology.
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Dispositivos Electrónicos Vestibles , Atención a la Salud , Humanos , Monitoreo Fisiológico , RespiraciónRESUMEN
Children in China's poor rural areas often have insufficient protein and micronutrient intake. There is little research about the effect of milk and egg supplementation published on these children. A prospective randomized controlled trial was applied to evaluate the effect of milk and egg supplementation on the growth and fitness of poor rural primary school students in southwest China whose physical development was below national averages. A total of 955 healthy students aged 6-13 years old were recruited. The intervention group (538) received 200 g milk and 50 g braised egg at each school day, while the control group (417) kept their normal diet and received no extra supplementation. Serum vitamin D levels were measured by an enzyme-linked immunosorbent assay. A mixed linear model with repeated measures was performed to analyze the efficacy of the supplementation. Statistically significant interactions between groups and time were seen in weight in boys, but not in girls. Significant improvement in vitamin D levels, the broad jump, and the 8 × 50 m shuttle run were observed in both genders. Therefore, the supplementation of egg and milk for two years might have a positive effect on growth and physical fitness and decreasing vitamin D deficiency in poor rural Chinese children.
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Estado Nutricional , Aptitud Física/fisiología , Población Rural , Instituciones Académicas , Estudiantes , Animales , Estatura , Peso Corporal , Estudios de Casos y Controles , Niño , China , Ingestión de Alimentos , Huevos , Femenino , Humanos , Masculino , Leche/química , Movimiento , Vitamina D/sangreRESUMEN
Aluminum (Al) toxicity is one of the primary factors limiting crop production in acid soils worldwide. The cell wall is the major target of Al toxicity owing to the presence of many Al binding sites. Previous studies have found that XTH, encoding xyloglucan endohydrolase (XEH) and xyloglucan endotransglucosylase (XET), could participate in cell wall extension and affect the binding ability of the cell wall to Al by impeding the activities of these two enzymes. In this study, we found that ZmXTH, an XTH gene in maize, was involved in Al detoxification. The Al-induced up-regulation of ZmXTH occurred in the roots, prominently in the root tips. Additionally, the expression of ZmXTH was specifically induced by Al3+ but no other divalent or trivalent cations. Compared with the wild-type Arabidopsis, ZmXTH overexpressing plants grew more healthy and had decreased Al content in their root and root cell wall after Al stress. Overall, the results suggest that ZmXTH could confer the Al tolerance of transgenic Arabidopsis plants by reducing the Al accumulation in their roots and cell walls.
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Aluminio , Arabidopsis/efectos de los fármacos , Glicosiltransferasas/metabolismo , Zea mays/enzimología , Aluminio/toxicidad , Arabidopsis/genética , Pared Celular/metabolismo , Regulación de la Expresión Génica de las Plantas , Glicosiltransferasas/genética , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Plantas Modificadas Genéticamente/efectos de los fármacos , Zea mays/genéticaRESUMEN
Objective@#To evaluate snack consumption and the influencing factors associated with student participation in the Nutrition Improvement Program, and to provide a scientific basis for improving the program.@*Methods@#Among the 50 monitoring counties that implemented the Compulsory Education Student Nutrition Improvement Program, two primary schools and two junior schools were randomly selected according to different food supply patterns (i.e., school, company, and mix). This study randomly selected one or two classes from each grade, which ranged from grade 3 to grade 9. A questionnaire, which addressed snack consumption and choice, was distributed to 27 374 students.@*Results@#The findings revealed that 14.0% of students from poor rural areas in central and western regions consumed snacks two or more times per day, and 21.6% of students spent 3 yuan or more on snacks each day. The top three choices of snacks included fruit and vegetables (50.6%), biscuits and bread (50.1%), and puffed food (40.0%). Students who had mothers who worked outside the home, parents who worked outside the home, who consumed corporate meals, and who had access to a small shop on campus were more likely to consume snacks one or more times per day(OR=1.35,1.19,1.11,1.51,P<0.05).@*Conclusion@#The phenomenon of snack consumption among primary and middle school students from poor rural areas in central and western regions is common, and the selection of unhealthy snacks was identified as a problem. A health education system with comprehensive support and guidance from individuals, families, schools, and society should be established to guide students to opt for healthier snacks.
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Objective@#To evaluate temporal trend in food supply among pilot schools involved in the National Nutrition Improvement Program for Rural Compulsory Education Students (NNIPRCES).@*Methods@#Ten percent of pilot schools were randomly selected and asked to report the information on food supplies. Daily intake of energy, carbohydrates and protein for each student were calculated and compared with the reference value in Nutrition Guidelines of School Meals (WS/T 554-2017).@*Results@#Energy and protein supply increased among those pilot schools. The supply of energy increased from 1 566.5 kcal in 2012 to 1 927.4 kcal in 2017, protein increased from 49.0 g to 61.0 g. The energy ratio of fat increased from 31.9% to 34.9%, while energy ratio of carbohydrate decreased significantly (F=83.38, 128.36, 20.27 and 17.28, all P<0.05). The proportion of reasonable energy supply from carbohydrate and fat in 2017 were 17.5% and 26.8%, respectively.@*Conclusion@#The supply of energy and macronutrients in the pilot areas were unreasonable, more measures including dietary guide and monitoring need to be adopted to improve students nutrition status among rural areas.
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Objective@#To analyze the prevalence of stunting among students received subsidies of the National Nutrition Improvement Program for rural Compulsory Education Students (NNIPRCES) during 2012-2017.@*Methods@#By using the data from 2012-2017 NNIPRCES survey, students aged 6-15 with valid height records were included. Stunting was defined according to the Screening Criteria of Malnutrition for School Age Children and Adolescents (WS/T 456—2014). To explore the association of the risk of stunting between different regions, gender or age groups in rural students.@*Results@#The prevalence of stunting among students aged 6-15 who received subsidies of NNIPRCES during 2012-2017 were 8.0%, 7.9%, 6.9%, 6.5%, 6.0% and 5.3%, declined by 2.7, 1.8, 4.0 percentage points in average, as well as in central and western region, respectively. The prevalence of stunting declined with 2.7 percentage points for boys and ,2.9 percentage points for girls. The prevalence of stunting declined most at the age of 13, with 4.0 percentage points.@*Conclusion@#The prevalence of stunting of students has declined after the implementation of NNIPRCES from 2012 to 2017. However, the total prevalence of stunting was still high and the development was unbalanced between central and western region, which requires more target intervening strategies to improve the nutritional status of students.
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Objective@#To investigate the changes of school absenteeism among students received Nutrition Improvement Program for Rural Compulsory Education Student (NIPCES), and to provide basic data for further nutritional health improvement for rural students.@*Methods@#Among 699 NIPCES monitored counties among 22 provinces across western and central China, 10%-30% of elementary and junior high schools were randomly selected as monitoring schools within each stratification according to the food supply pattern (school canteen, company and mix) in each county, school absenteeism information were collected and analyzed from 2012 to 2017.@*Results@#The total rate of student absenteeism was 26.0 per 10 000. From 2012 to 2016, it dropped from 30.8 per 10 000 to 23.4 per 10 000 year by year, but it increased again in 2017(28.2 per 10 000). The rate of school absenteeism in the western region (29.4 per 10 000) was higher than that in the central region (21.5 per 10 000); The sick leave rate (15.0 per 10 000) of primary school students was higher than that of junior high school students (13.4 per 10 000), and the rate of personal leave absences (16.9 per 10 000) of junior high school students was higher than that of elementary school students(9.9 per 10 000); the absentees rate in mixed-food supply schools (28.5 per 10 000) was higher than that in canteen food supply schools(26.4 per 10 000), the latter was higher than that of company food supply schools(25.0 per 10 000). The rate of sick leave absenteeism was highest in December(18.4 per 10 000), and the rate of personal leave absenteeism in June was highest(14.6 per 10 000).@*Conclusion@#The rate of school absenteeism among students in the NIPCES area showed an overall downward trend year by year. The absentee rate of students varies by regions, grade, food supply patterns and school locations.
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Objective@#To analyze changes of school canteen construction and canteen meal provision in surveilled schools after the initiation of the National Nutrition Improvement Program for Rural Compulsory Education Student (NNIPRCES), therefore to provide data basis for improving efficacy of school canteen meals.@*Methods@#From 2012 to 2017, among the 699 trial counties in 22 provinces under NNIPRCES, at least 10% of elementary schools and middle schools with each food supply model (canteen meals, enterprise meals, and family meals) were randomly selected in each county in each year. Questionnaire survey was conducted to collect school canteen construction and meal provision information. The sample size were around 8 000 to 11 000 schools every year.@*Results@#From 2012 to 2017, the proportion of schools that have canteens only, have both canteen and dining room, as well as those have canteen and dining room with tables and chairs significantly increased with years(χ 2=3 043.95, 6 383.85, 6 731.17, P<0.01). The proportion of schools having canteen increased from 59.5% in 2012 to 87.0% in 2017. The proportion of schools with canteen providing breakfast, lunch or dinner varied across years(χ 2=51.85, 144.96, 189.19, P<0.01). The varieties of food groups of three meals all significantly increased during 2012, 2014 and 2017(χ 2=702.30, 892.38, 550.55, P<0.01). The canteen construction indicators, proportion of canteens providing three meals, and food groups included in three meals all significantly differed between elementary schools and middle schools, also between schools of central area and western area(P<0.05). The changing patterns with year were significantly different in elementary schools and middle schools, and in schools of central area and western area(P<0.05).@*Conclusion@#After the implementation of NNIPRCES, canteen construction and food variety in canteen meals significantly improved during 2012 to 2017. However, there are still gaps between changes of canteen construction and canteen meal provision. It is necessary to overcome obstacles to further increase the proportion of schools with canteen offering meals and the variety of food of meals.