39 research outputs found
From Offline to Online: A Study on the Practice of Learners' Self-Regulated Learning Based on Bourdieu's Theory
The research is financed by Reform of the Practical Teaching Mode of Enterprise Resource Planning Based on the Cultivation of Students' Learning Ability(55611219) Abstract At present, the migration of learners from offline classroom to online learning space faces the problem of high dropout rate. Previous research suggested that self-regulated learning practice is a key factor affecting the effectiveness of online learning, but the research on the driving causes of self-regulated learning is still in the exploration stage. In the study, the impact on self-regulated learning practice is investigated. Based on the practice theory of Bourdieu, a large number of interviews was conducted by the grounded theory methodology. The results indicated that the impact on learners' self-regulated learning practice was accomplished by four aspects, i.e., online field structured, capitals reproduced, new habitus generated and practice of self-regulated learning. The managerial implications from our study are discussed finally. Keywords: Bourdieu theory; self-regulated learning; practice DOI: 10.7176/EJBM/11-32-01 Publication date: November 30th 201
Design and Evaluation of a Surfactant–Mixed Metal Hydroxide-Based Drilling Fluid for Maintaining Wellbore Stability in Coal Measure Strata
Co-exploitation of coal measure gases (coalbed gas, shale gas, and tight sandstone gas) puts a higher requirement on drilling fluids. Conventional drilling fluids have disadvantages, such as causing problems of borehole collapse, formation damage, and water blockage. This paper proposes a set of high inhibitive and low-damage drilling fluids that function by electrical inhibition and neutral wetting. Zeta potential results showed that the negative electrical property of Longtan coal in Bijie, Guizhou, can be reversed by organic mixed metal hydroxide (MMH) and the cationic surfactant alkyl trimethylammonium bromide (CS-5) from −3.63 mV to 19.75 mV and 47.25 mV, respectively. Based on the contact angle and Fourier Transform Infrared Spectroscopy (FT-IR) results, it can be concluded that chemical adsorption dominates between the Longmaxi shale and surfactants, and physical adsorption between the Longtan coal and surfactants. A compound surfactant formula (0.001 wt% CS-4 + 0.001 wt% CS-1 + 0.001 wt% CS-3), which could balance the wettability of the Longmaxi shale and the Longtan coal, making them both appear weakly hydrophilic simultaneously, was optimized. After being treated by the compound surfactants, the contact angles of the Longmaxi shale and the Longtan coal were 89° and 86°, respectively. Pressure transmission tests showed that the optimized combination of compound surfactants and inorganic MMH (MMH-1) could effectively reduce permeability of the Longmaxi shale and the Longtan coal, thus retarding pore pressure transmission in coal measure strata. Then, the proposed water-based drilling fluid (WBDF) system (4 wt% sodium bentonite + 1.5 wt% sodium carboxymethyl cellulose + 2 wt% lignite resin + 5 wt% potassium chloride + 3 wt%MMH-1 + 0.001 wt% CS-4 + 0.001 wt% CS-1 + 0.001 wt% CS-3) was evaluated based on parameters including rheology, American Petroleum Institute (API) filtration, electrical property, wettability, inhibition capability, reservoir protection characteristics, and anti-pollution performance. It had an API filtration of 7 mL, reservoir damage rate of 10%, moderate and acceptable viscosity, strong inhibition capability to coal measure strata rocks, good tolerance to inorganic pollutants and drilling cuttings, and environmentally friendly properties. It could meet wellbore stability and reservoir protection requirements in the co-exploitation of coal measure gases
The Prevalence of Hyperuricemia and Its Correlates among Adults in China: Results from CNHS 2015–2017
This study aimed to investigate the prevalence of hyperuricemia (HUA) and associated risk factors in Chinese adults aged 18 to 59 years. All the data were collected from the China Nutrition and Health Surveillance during the period 2015–2017, which adopted a stratified, multistage, random sampling method on a national scale. A total of 52,627 participants aged 18 years or older were included in this study. The definition of hyperuricemia was 420 μmol/L for male and 360 μmol/L for female. The Rao–Scott chi-square test was used to compare the differences in prevalence between or among the subgroups. A weighted two-level multivariate survey-logistic regression was used to detect the correlations between HUA and demographic, physical, lifestyle and metabolic factors. The total prevalence of HUA was 15.1%, and that was higher in male, current smokers, higher BMI and less physical activities subgroups, and also in noninfectious chronic diseases (NCDs) subgroups. The subgroups of non-vegetarian diet, insufficient vegetable intakes and excessive red meat and alcohol intakes had significantly higher HUA prevalence. After introducing all the variables in the survey-logistic regression, gender, age, BMI, physically active, hypertension, diabetes mellitus, bean and nut intake, vegetable intake, red meat intake, alcohol consumption and vegetarian were associated with HUA. Among the significant variables, age and physical active served as a protective factor, and BMI showed to be a risk factor for HUA. Hypertension and dyslipidemia could increase the risk for HUA, while diabetes mellitus was shown a negative association with it. For dietary factors, vegetarian diet, sufficient beans and nuts and vegetables intake could lower the risk of HUA, but more alcohol could increase the risk of HUA. Dietary factor played a key role in HUA. It suggested that the intervention of dietary factor should receive more attention to ameliorate the high prevalence of HUA in China
Design and Evaluation of a Surfactant–Mixed Metal Hydroxide-Based Drilling Fluid for Maintaining Wellbore Stability in Coal Measure Strata
Effects of Different Rearing Systems on Lueyang Black-Bone Chickens: Meat Quality, Amino Acid Composition, and Breast Muscle Transcriptome
The quality of poultry products depends on genotype, rearing system, and environment. The aim of this study was to investigate the effects of different rearing systems on meat quality, amino acid composition, and breast muscle transcriptome from Lueyang black-bone chickens. Lueyang black-bone chickens (n = 900) were randomly divided into three groups (cage, flat-net, and free-range groups), with three replicates per group (100 chickens per replicate). At 16 weeks, a total of 36 healthy chickens (six males and six females per group) were collected, and their breast muscles were sampled to detect meat quality parameters, amino acid composition, and fatty acid contents. Furthermore, breast muscles from six random hens in each group were used for RNA-seq analysis. The results revealed that the values of pH, shear force, inosine monophosphate (IMP), palmitic acid, and linoleic acid in the free-range group were significantly higher than those in the caged group (p p p p > 0.05). The breast muscle transcriptome results showed that there were 291, 131, and 387 differently expressed genes (DEGs) among the three comparison groups (caged vs. free-range, flat-net vs. caged, and flat-net vs. free-range, respectively) that were mainly related to muscle development and amino acid metabolism pathways. To validate the accuracy of the transcriptome data, eight genes (GOS2, ASNS, NMRK2, GADL1, SMTNL2, SLC7A5, AMPD1, and GLUL) which relate to fat deposition, skeletal muscle function, and flavor formation were selected for Real-time Quantitative PCR (RT-qPCR) verification. In conclusion, these results suggested that rearing systems significantly influenced the meat quality and gene expression of Lueyang black-bone chickens. All the data proved that free-range and flat-net systems may provide better flavor to consumers by affecting the deposition of flavor substances and the expression of related genes. These findings will provide a valuable theoretical basis for the rearing system selection in the poultry industry
Self-Reported Dietary Management Behaviors and Dietary Intake among Chinese Adults with Diabetes: A Population-Based Study
Few studies have analyzed the implementation of dietary management in Chinese adults with diabetes. Thus, we assessed and compared dietary intake and diet quality between diabetic patients with and without dietary management behaviors (DPDM vs. NDPDM), and evaluated the adherence to dietary guidelines in both groups of patients. The data were obtained from the 2002, 2010–2013, and 2015 China National Nutrition Survey. A total of 69,583, 67,177, and 96,631 subjects participated in the 2002, 2010–2013, and 2015 survey rounds, respectively. The dietary intake data were measured using 3-day 24 h dietary recalls and weighed records of household condiments. The China Healthy Diet Index (CHDI) was used to evaluate diet quality. The study included 6229 patients with diabetes, of which 78% had dietary management behaviors. The diabetic patients with dietary management behaviors showed higher percentages of energy from high-quality carbohydrates, animal protein, saturated fatty acids, and unsaturated fatty acids and lower percentages from low-quality carbohydrates and plant protein than NDPDM. The diabetic patients with dietary management behaviors also had lower intakes of cereals and tubers and higher intakes of vegetables than NDPDM. The total CHDI score of DPDM was higher than NDPDM (56.3 ± 12.7 vs. 54.1 ± 12.3). The proportion of DPDM meeting the recommended intake for different food items ranged from 3.3% to 42.8% and from 3.0% to 39.2% in NDPDM. The diabetic patients with dietary management behaviors showed better adherence to dietary guidelines and higher diet quality scores than NDPDM, while the overall adherence was poor in both groups of patients. Our findings suggested that measures are needed to promote and refine dietary management behaviors, which can help to improve disease management in diabetic patients
The Association of Dietary Magnesium and Prediabetes in Childbearing Chinese Women: Results from China Nutrition and Health Surveillance (2015–2017)
Although several studies have shown the relationship between magnesium and diabetes, there are few studies regarding the association between magnesium status and prediabetes. This study aimed to examine the association between dietary magnesium intake and the risk of prediabetes in childbearing Chinese women (18–44 years). A total of 1981 participants without diabetes were randomly selected from China Nutrition and Health Surveillance (CNHS) in 2015 by considering the regional types and monitoring points, including 1420 normal fasting glucose (NFG) people and 561 prediabetes cases. The Food Frequency Questionnaire (FFQ) and inductively coupled plasma mass spectrometry (ICP-MS) measured dietary and plasma magnesium. The results of this study showed that dietary magnesium intake was inversely associated with fasting plasma glucose. For every 100 mg of magnesium intake, there was a 0.052 mmol/L (95% CI 0.019, 0.085) reduction in fasting plasma glucose (p = 0.002). Compared with the lowest intake quartile (<350.10 mg/day), the third and fourth quartiles (≥405.41 mg/day) reduced the odds risk of prediabetes (OR = 0.63, 95% CI 0.46, 0.88, p = 0.020) by approximately 37%. The dose-response curves for the association between magnesium intake and prediabetes followed an L shape. The odds ratio of prediabetes decreased significantly with increasing dietary Mg intake at less than 410 mg/day, and then the curve leveled off or slightly increased. This study found a negative association between dietary magnesium intake and prediabetes in childbearing Chinese women. The risk of prediabetes was reduced with increasing dietary magnesium intake, and the threshold value was 410 mg/day. This suggests that childbearing women also need to pay attention to their magnesium status
Adiponectin Upregulates MiR-133a in Cardiac Hypertrophy through AMPK Activation and Reduced ERK1/2 Phosphorylation.
Adiponectin and miR-133a are key regulators in cardiac hypertrophy. However, whether APN has a potential effect on miR-133a remains unclear. In this study, we aimed to investigate whether APN could regulate miR-133a expression in Angiotensin II (Ang II) induced cardiac hypertrophy in vivo and in vitro. Lentiviral-mediated adiponectin treatment attenuated cardiac hypertrophy induced by Ang II infusion in male wistar rats as determined by reduced cell surface area and mRNA levels of atrial natriuretic peptide (ANF) and brain natriuretic peptide (BNP), also the reduced left ventricular end-diastolic posterior wall thickness (LVPWd) and end-diastolic interventricular septal thickness (IVSd). Meanwhile, APN elevated miR-133a level which was downregulated by Ang II. To further investigate the underlying molecular mechanisms, we treated neonatal rat ventricular myocytes (NRVMs) with recombinant rat APN before Ang II stimulation. Pretreating cells with recombinant APN promoted AMP-activated protein kinase (AMPK) phosphorylation and inhibited ERK activation. By using the inhibitor of AMPK or a lentiviral vector expressing AMPK short hairpin RNA (shRNA) cancelled the positive effect of APN on miR-133a. The ERK inhibitor PD98059 reversed the downregulation of miR-133a induced by Ang II. These results indicated that the AMPK activation and ERK inhibition were responsible for the positive effect of APN on miR-133a. Furthermore, adiponectin receptor 1 (AdipoR1) mRNA expression was inhibited by Ang II stimulation. The positive effects of APN on AMPK activation and miR-133a, and the inhibitory effect on ERK phosphorylation were inhibited in NRVMs transfected with lentiviral AdipoR1shRNA. In addition, APN depressed the elevated expression of connective tissue growth factor (CTGF), a direct target of miR-133a, through the AMPK pathway. Taken together, our data indicated that APN reversed miR-133a levels through AMPK activation, reduced ERK1/2 phosphorylation in cardiomyocytes stimulated with Ang II, revealing a previously undemonstrated and important link between APN and miR-133a
Fluorescent metallacycle-cored polymers via covalent linkage and their use as contrast agents for cell imaging
A sustainable and profitable biorefinery strategy for efficiently converting lignocellulose to furfural, glucose and phenolic compounds
The sustainability and profitability of biorefineries are based on efficient utilization of all components of lignocellulosic biomass. However, the resistance of the lignocellulosic structure and the differences in the physicochemical properties of its main components are typical challenges for most lignocellulosic fractionation approaches. Here, we demonstrate a fractionation strategy that is able to efficiently fractionate the whole lignocellulosic component and convert it into a range of valuable products. The aim of our method is to maintain the quality of lignin components by adding isopropanol, while formic acid and molten salt hydrate (LiCl·3H2O) promote the dissolution of hemicellulose and lignin. Subsequently, the as-obtained cellulose is readily saccharified due to the invasion of the dense crystal structure, and enzymatic hydrolysis yields 728.3 mg g−1 glucose. After simple separation, 75.6 mol% furfural was produced from hemicellulose in the LiCl·H2O/γ-valerolactone (GVL) biphasic system and 75.7 wt% phenolic mono-/oligomers were produced from lignin hydrolyzed in formic acid/isopropanol(aq.). Attributed to this rational design, the techno-economic analysis predicts a revenue of 122.66 USD by processing 100 kg of waste bamboo using the above developed approach. In this process, all solvents participate in both fractionation and catalytic conversion and are allowed to be recycled, which is in line with the principles of green chemistry