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"Han, Mei"
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l-Aspartate: An Essential Metabolite for Plant Growth and Stress Acclimation
2021
L-aspartate (Asp) serves as a central building block, in addition to being a constituent of proteins, for many metabolic processes in most organisms, such as biosynthesis of other amino acids, nucleotides, nicotinamide adenine dinucleotide (NAD), the tricarboxylic acid (TCA) cycle and glycolysis pathway intermediates, and hormones, which are vital for growth and defense. In animals and humans, lines of data have proved that Asp is indispensable for cell proliferation. However, in plants, despite the extensive study of the Asp family amino acid pathway, little attention has been paid to the function of Asp through the other numerous pathways. This review aims to elucidate the most important aspects of Asp in plants, from biosynthesis to catabolism and the role of Asp and its metabolic derivatives in response to changing environmental conditions. It considers the distribution of Asp in various cell compartments and the change of Asp level, and its significance in the whole plant under various stresses. Moreover, it provides evidence of the interconnection between Asp and phytohormones, which have prominent functions in plant growth, development, and defense. The updated information will help improve our understanding of the physiological role of Asp and Asp-borne metabolic fluxes, supporting the modular operation of these networks.
Journal Article
Rain-Shelter Cultivation Modifies Carbon Allocation in the Polyphenolic and Volatile Metabolism of Vitis vinifera L. Chardonnay Grapes
2016
This study investigated the effect of rain-shelter cultivation on the biosynthesis of flavonoids and volatiles in grapes, with an aim of determining whether rain-shelter application could help to improve the sensory attributes and quality of grapes. Vitis vinifera L. Chardonnay grapes, grown in the Huaizhuo basin region of northern China, were selected within two consecutive years. A rain-shelter roof was constructed using a colorless polyethylene (PE) film with a light transmittance of 80%. Results showed that rain-shelter treatment did not affect the accumulation of soluble solids during grape maturation. However, the allocation of assimilated carbon in phenolic and volatile biosynthetic pathways varied significantly, leading to alterations in polyphenolic and volatile profiles. The rain-shelter cultivation enhanced the concentration of flavan-3-ols via the flavonoid-3'5'-hydroxylase (F3'5'H) pathway, but reduced the level of flavonols and flavan-3-ols via the flavonoid-3'-hydroxylase (F3'H) pathway. In addition, the rain-shelter cultivation significantly enhanced the synthesis of fatty acid-derived volatiles, isoprene-derived terpenoids and amino acid-derived branched-chain aliphatics, but led to a decrease in the accumulation of isoprene-derived norisoprenoids and amino acid-derived benzenoids. Principal component analysis revealed some key compounds that differentiated the grapes cultivated under open-field and rain-shelter conditions. Moreover, the effect of the rain-shelter application on the accumulation of these compounds appeared to be vintage dependent. The alteration of their profiles caused by the rain-shelter treatment was significant in the vintage that received higher rainfall, which usually took place in the first rapid growth and veraison phases.
Journal Article
Calibrations of Low-Cost Air Pollution Monitoring Sensors for CO, NO2, O3, and SO2
by
Wang, Yinghong
,
Tang, Xiao
,
Mei, Han
in
Air pollution
,
electrochemical air quality sensors
,
Electrodes
2021
Pollutant gases, such as CO, NO2, O3, and SO2 affect human health, and low-cost sensors are an important complement to regulatory-grade instruments in pollutant monitoring. Previous studies focused on one or several species, while comprehensive assessments of multiple sensors remain limited. We conducted a 12-month field evaluation of four Alphasense sensors in Beijing and used single linear regression (SLR), multiple linear regression (MLR), random forest regressor (RFR), and neural network (long short-term memory (LSTM)) methods to calibrate and validate the measurements with nearby reference measurements from national monitoring stations. For performances, CO > O3 > NO2 > SO2 for the coefficient of determination (R2) and root mean square error (RMSE). The MLR did not increase the R2 after considering the temperature and relative humidity influences compared with the SLR (with R2 remaining at approximately 0.6 for O3 and 0.4 for NO2). However, the RFR and LSTM models significantly increased the O3, NO2, and SO2 performances, with the R2 increasing from 0.3–0.5 to >0.7 for O3 and NO2, and the RMSE decreasing from 20.4 to 13.2 ppb for NO2. For the SLR, there were relatively larger biases, while the LSTMs maintained a close mean relative bias of approximately zero (e.g., <5% for O3 and NO2), indicating that these sensors combined with the LSTMs are suitable for hot spot detection. We highlight that the performance of LSTM is better than that of random forest and linear methods. This study assessed four electrochemical air quality sensors and different calibration models, and the methodology and results can benefit assessments of other low-cost sensors.
Journal Article
Reasons for patient non-compliance with compression stockings as a treatment for varicose veins in the lower limbs: A qualitative study
by
Du, Jian-Shi
,
Han, Dong-Mei
,
Gong, Jian-Mei
in
Analysis
,
Biology and Life Sciences
,
Compression
2020
The study aims to explore the comprehensive reasons for patients' non-compliance with graded elastic compression stockings (GECS) as the treatment for lower limb varicose veins. Phenomenological analysis was applied in this qualitative study. The patients diagnosed with lower limb varicose veins and undergoing elective surgery who showed non-compliance with GECS as the treatment were invited to have semi-structured, in-depth, face-to-face interviews. Colaizzi method was employed to analyze the data for emerging themes associated with the reasons for patients' non-compliance. Four main themes and nine subthemes related to the reasons for non-compliance with GECS for lower limb varicose veins were summarized. The main themes that emerged were (1) gaps in the knowledge of GECS therapy as a treatment for lower limb varicose veins, (2) few recommendations from the doctors and nurses, (3) disadvantages of GECS, and (4) sociopsychological factors. These themes provide data for policy and planning to improve patients' compliance with GECS in China. Patients, healthcare professionals, and policy makers should share the responsibility to improve patients' compliance with GECS therapy.
Journal Article
Research on the Countermeasures of College Students' innovation and entrepreneurship development under the perspective of \Internet +\
\"Internet +\" innovation and entrepreneurship education is a new educational concept, and it is the inherent requirement of university education reform. In this paper, we take the cultivation of College Students' \"Internet +\" innovation and entrepreneurship capabilities as the core, in-depth analysis of the major problems encountered by college students in \"Internet +\" innovation and entrepreneurship, and realize the profound educational reform from four levels of government, universities, enterprises and university students. Based on the evaluation index of graduate innovation and entrepreneurship education, this paper constructs an evaluation model of graduate innovation and entrepreneurship education based on analytic hierarchy process (AHP), which provides basis and reference criteria for the training and evaluation of graduate innovation and entrepreneurship education.
Journal Article
Soil metagenomics reveals the effect of nitrogen on soil microbial communities and nitrogen-cycle functional genes in the rhizosphere of Panax ginseng
2024
Nitrogen (N) is the primary essential nutrient for ginseng growth, and a reasonable nitrogen application strategy is vital for maintaining the stability of soil microbial functional communities. However, how microbial-mediated functional genes involved in nitrogen cycling in the ginseng rhizosphere respond to nitrogen addition is largely unknown. In this study, metagenomic technology was used to study the effects of different nitrogen additions (N0: 0, N1: 20, N2: 40 N g/m 2 ) on the microbial community and functional nitrogen cycling genes in the rhizosphere soil of ginseng, and soil properties related to the observed changes were evaluated. The results showed that N1 significantly increased the soil nutrient content compared to N0, and the N1 ginseng yield was the highest (29.90% and 38.05% higher than of N0 and N2, respectively). N2 significantly decreased the soil NO 3 – N content (17.18 mg/kg lower than N0) and pH. This resulted in a decrease in the diversity of soil microorganisms, a decrease in beneficial bacteria, an increase in the number of pathogenic microorganisms, and an significant increase in the total abundance of denitrification, assimilatory nitrogen reduction, and dissimilatory nitrogen reduction genes, as well as the abundance of nxrA and napA genes (17.70% and 65.25% higher than N0, respectively), which are functional genes involved in nitrification that promote the soil nitrogen cycling process, and reduce the yield of ginseng. The results of the correlation analysis showed that pH was correlated with changes in the soil microbial community, and the contents of soil total nitrogen (TN), ammonium nitrogen (NH 4 + -N), and alkaline-hydrolyzed nitrogen (AHN) were the main driving factors affecting the changes in nitrogen cycling functional genes in the rhizosphere soil of ginseng. In summary, nitrogen addition affects ginseng yield through changes in soil chemistry, nitrogen cycling processes, and functional microorganisms.
Journal Article
Inflammation and atherosclerosis: signaling pathways and therapeutic intervention
2022
Atherosclerosis is a chronic inflammatory vascular disease driven by traditional and nontraditional risk factors. Genome-wide association combined with clonal lineage tracing and clinical trials have demonstrated that innate and adaptive immune responses can promote or quell atherosclerosis. Several signaling pathways, that are associated with the inflammatory response, have been implicated within atherosclerosis such as NLRP3 inflammasome, toll-like receptors, proprotein convertase subtilisin/kexin type 9, Notch and Wnt signaling pathways, which are of importance for atherosclerosis development and regression. Targeting inflammatory pathways, especially the NLRP3 inflammasome pathway and its regulated inflammatory cytokine interleukin-1β, could represent an attractive new route for the treatment of atherosclerotic diseases. Herein, we summarize the knowledge on cellular participants and key inflammatory signaling pathways in atherosclerosis, and discuss the preclinical studies targeting these key pathways for atherosclerosis, the clinical trials that are going to target some of these processes, and the effects of quelling inflammation and atherosclerosis in the clinic.
Journal Article
Electrochemical Sensor Based on Co-MOF for the Detection of Dihydromyricetin in Ampelopsis grossedentata
2025
Dihydromyricetin (DMY), as the main active ingredient in Ampelopsis grossedentata, is a naturally occurring flavonoid that has attracted extensive attention for its multiple biological activities. For the quick and accurate measurement of DMY, a novel electrochemical sensor based on a glassy carbon electrode (GCE) modified with a cobalt metal-organic framework (Co-MOF) was proposed in this work. The Co-MOF was synthesized via a single-step hydrothermal process using Co(NO3)2·6H2O. Fourier infrared spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy were used to study the morphology and structure of the synthesized Co-MOF. Utilizing differential pulse voltammetry and cyclic voltammetry methods, the effectiveness of DMY electro-oxidation on the Co-MOF/GCE was examined. The results showed that, in comparison to the bare GCE, the electro-oxidation peak current of DMY was considerably increased by the Co-MOF/GCE. The detection limit was 0.07 μM, and the peak current demonstrated two linear relationships in the ranges of 0.2−20 μM and 20−100 μM, with the linear equations of Ip (μA) = 0.4729c (μM) + 1.0822 (R2 = 0.9913) and Ip (μA) = 0.0939c (μM) + 8.4178 (R2 = 0.9971), respectively. The average DMY content in Ampelopsis grossedentata samples was measured to be 3.275 μM, with a good recovery of 108.27% and a relative standard deviation value of 3.46%. The proposed method is simple, rapid and sensitive and can be used for the determination of DMY in Ampelopsis grossedentata.
Journal Article
Intracellular membranes of bacterial endospores are reservoirs for spore core membrane expansion during spore germination
2018
Bacterial endospores are formed by certain bacteria, such as
Bacillus subtilis
or the pathogenic
Bacillus anthracis
and
Clostridioides difficile
, to allow survival in environmental conditions which are lethal to vegetative bacteria. The spores possess a particular architecture and molecular inventory which endow them with a remarkable resistance against desiccation, heat and radiation. Another remarkable spore feature is their rapid return to vegetative growth during spore germination and outgrowth. The underlying processes of this latter physiological and morphological transformation involve a number of different events, some of which are mechanistically not entirely understood. One of these events is the expansion of the central spore core, which contains the DNA, RNA and most spore enzymes. To date, it has been unclear how the ~1.3- to 1.6-fold expansion of the core membrane surface area that accompanies core expansion takes place, since this occurs in the absence of significant if any ATP synthesis. In the current work, we demonstrate the presence of intracellular membrane structures in spores located just below the core membrane. During spore germination these internal core membranes disappear when the core size increases, suggesting that they are integrated into the core membrane to allow core expansion. These intracellular membranes are most probably present as more or less compressed vesicles or tubules within the dormant spore core. Investigations of spores from different species suggest that these intracellular membrane structures below the core membrane are a general feature of endospore forming bacteria.
Journal Article
The threshold of alpha-fetoprotein (AFP) for the diagnosis of hepatocellular carcinoma: A systematic review and meta-analysis
2020
Hepatocellular carcinoma (HCC) has become a pressing health problem facing the world today due to its high morbidity, high mortality, and late discovery. As a diagnostic criteria of HCC, the exact threshold of Alpha-fetoprotein (AFP) is controversial. Therefore, this study was aimed to systematically estimate the performance of AFP in diagnosing HCC and to clarify its optimal threshold.
Medline and Embase databases were searched for articles indexed up to November 2019. English language studies were included if both the sensitivity and specificity of AFP in the diagnosis of HCC were provided. The basic information and accuracy data included in the studies were extracted. Combined estimates for sensitivity and specificity were statistically analyzed by random-effects model using MetaDisc 1.4 and Stata 15.0 software at the prespecified threshold of 400 ng/mL, 200 ng/mL, and the range of 20-100 ng/mL. The optimal threshold was evaluated by the area under curve (AUC) of the summary receiver operating characteristic (SROC).
We retrieved 29,828 articles and included 59 studies and 1 review with a total of 11,731 HCC cases confirmed by histomorphology and 21,972 control cases without HCC. The included studies showed an overall judgment of at risk of bias. Four studies with AFP threshold of 400 ng/mL showed the summary sensitivity and specificity of 0.32 (95%CI 0.31-0.34) and 0.99 (95%CI 0.98-0.99), respectively. Four studies with AFP threshold of 200 ng/mL showed the summary sensitivity and specificity of 0.49 (95%CI 0.47-0.50) and 0.98 (95%CI 0.97-0.99), respectively. Forty-six studies with AFP threshold of 20-100 ng/mL showed the summary sensitivity and specificity of 0.61 (95%CI 0.60-0.62) and 0.86 (95%CI 0.86-0.87), respectively. The AUC of SROC and Q index of 400 ng/mL threshold were 0.9368 and 0.8734, respectively, which were significantly higher than those in 200 ng/mL threshold (0.9311 and 0.8664, respectively) and higher than those in 20-100 ng/mL threshold (0.8330 and 0.7654, respectively). Furthermore, similar result that favored 400 ng/mL were shown in the threshold in terms of AFP combined with ultrasound.
AFP levels in serum showed good accuracy in HCC diagnosis, and the threshold of AFP with 400 ng/mL was better than that of 200 ng/mL in terms of sensitivity and specificity no matter AFP is used alone or combined with ultrasound.
Journal Article