Bedtime procrastination related to loneliness among Chinese university students during post-pandemic period: a moderated chain mediation model.

BACKGROUND: This study examined the relationship between loneliness and bedtime procrastination among Chinese university students, the mediating effects of COVID-19 risk perception and self-regulatory fatigue, and connectedness to nature's protective role, post pandemic. METHODS: We recruited 855 students to complete the Loneliness, Perceived Risk of COVID-19 Pandemic, Self-Regulatory Fatigue, Bedtime Procrastination, and Connectedness to Nature Scales. Data for descriptive statistics, correlation analysis, and moderated chain mediation effects were analyzed using SPSS 24.0 and process 3.5 macros. RESULTS: Loneliness positively correlated with bedtime procrastination, COVID-19 risk perception mediated the impact of loneliness on bedtime procrastination, self-regulatory fatigue mediated the effect of loneliness on bedtime procrastination, and COVID-19 risk perception and self-regulatory fatigue mediated the effect between loneliness and bedtime procrastination. Furthermore, connectedness to nature mediated the impact of COVID-19 risk perception on self-regulatory fatigue. CONCLUSIONS: The results indicate the effects and potential mechanisms of loneliness on bedtime procrastination after the relaxation of the pandemic prevention and control policy in China from the perspective of self-regulatory resources and provide insights into improving university students' sleep routine and mental health post pandemic.

Oligosaccharides from black ginseng innovatively prepared by low-temperature steam-heating process ameliorate cognitive impairment in Alzheimer's disease mice via the Keap-1/Nrf2 pathway.

BACKGROUND: Our objective in this study was to evaluate the effectiveness of oligosaccharides extracted from black ginseng (OSBG), innovatively prepared by a low-temperature steam-heating process, in the improvement of learning and memory impairment in mice, as well as the mechanism(s). RESULTS: Eight carbohydrates involving isomaltose and maltotetraose were detected in black gensing; monosaccharide residues including mannose and rhamnose were also discovered. OSBG-treated mice showed significant amelioration in recognition and spatial memory deficits compared to the scopolamine group. OSBG could decrease acetylcholinesterase activity in a tissue-dependent fashion but not in a dose-dependent manner. Furthermore, in contrast, OSBG administration resulted in significant upregulation superoxide dismutase, glutathione, glutathione peroxidase (GPx), and Kelch-like ECH-associated protein 1, downregulation of malondialdehyde and nuclear factor erythroid 2-related factor 2 in the tissues. Finally, at the genus level, we observed that the OSBG interventions increased the relative abundance of probiotics (e.g., Barnesiella, Staphylococcus, Clostridium_XlVb) and decreased pernicious bacteria such as Eisenbergiella and Intestinimonas, compared to the Alzheimer's disease mouse model group. Herein, our results demonstrate that OSBG restores the composition of the scopolamine-induced intestinal microbiota in mice, providing homeostasis of gut microbiota and providing evidence for microbiota-regulated therapeutic potential. CONCLUSION: Our results showed for the first time a clear role for OSBG in improving scopolamine-induced memory impairment by inhibiting cholinergic dysfunction in a tissue-dependent manner. Additionally, OSBG administration relieved oxidative stress by activating the Keap-1/Nrf2 pathway and modulating the gut microbiota. Collectively, OSBG may be a promising target for neuroprotective antioxidants for improving memory and cognition in Alzheimer's disease patients. © 2024 Society of Chemical Industry.

An improved sulfur-nitroso-proteome strategy for global profiling of sulfur-nitrosylated proteins and sulfur-nitrosylation sites in mice.

Comprehensive sulfur-nitrosylation (SNO) proteome coverage in complex biological systems remains challenging as a result of the low level of endogenous S-nitrosylation and its chemical instability. Herein, we optimized the synthesis route of SNOTRAP (SNO trapping by triaryl phosphine) probe and the proteomics pipeline (including preventing over-alkylation, sample washing, trypsin digestion). Preventing overalkylation was found to be the key factor resulting in a higher number of identified SNO proteins by evaluating various experimental conditions. With the improved SNOTRAP-based proteomic pipeline, we achieved an improvement of ∼10-fold on identification efficiency, and identified 1181 SNO proteins (1714 SNO sites) in mouse brain, representing the largest repository of endogenous S-nitrosylation. Moreover, we identified the consensus motif of SNO sites, suggesting the correlation with local hydrophobicity, acid-base catalysis, and the surrounding secondary structures for modification of specific cysteines by NO. Collectively, we provide a universal pipeline for the high-coverage identification of low-abundance SNO proteins with high enrichment efficiency, high specificity (98%), good reproducibility, and easy implementation, contributing to the elucidation of the mechanism(s) of nitrosative stress in multiple diseases.

A polyethylene glycol enhanced ligation-triggered self-priming isothermal amplification for the detection of SARS-CoV-2 D614G mutation.

We presented a polyethylene glycol (PEG) enhanced ligation-triggered self-priming isothermal amplification (PEG-LSPA) for the detection D614G mutation in S-glycoprotein of SARS-CoV-2. PEG was employed to improve the ligation efficiency of this assay by constructing a molecular crowding environment. Two hairpin probes (H1 and H2) were designed to contain 18 nt and 20 nt target binding site at their 3' end and 5' end, respectively. In presence of target sequence, it complemented with H1 and H2 to trigger ligation by ligase under molecular crowding condition to form ligated H1-H2 duplex. Then 3' terminus of the H2 would be extended by DNA polymerase under isothermal conditions to form a longer extended hairpin (EHP1). 5' terminus of EHP1 with phosphorothioate (PS) modification could form hairpin structure due to the lower Tm value. The resulting 3' end overhang would also fold back as a new primer to initiate the next round of polymerization, resulting in the formation of a longer extended hairpin (EHP2) containing two target sequence domains. In the circle of LSPA, long extended hairpin (EHPx) containing numerous target sequence domains was produced. The resulting DNA products can be monitored in real-time fluorescence signaling. Our proposed assay owns an excellent linear range from 10 fM to 10 nM with a detection limit down to 4 fM. Thus, this work provides a potential isothermal amplification method for monitoring mutations in SARS-CoV-2 variants.

Interaction of isoquinoline alkaloids with pyrimidine motif triplex DNA by mass spectrometry and spectroscopies reveals diverse mechanisms.

Isoquinoline alkaloids represent an important class of molecules due to their broad range of pharmacology and clinical utility. Prospective development and use of these alkaloids as effective anticancer agents have elicited great interest. In this study, in order to reveal structure-activity relationship, we present the characterization of bioactive isoquinoline alkaloid-DNA triplex interactions, with particular emphasis on the sequence selectivity and preference of binding to the two types of DNA triplexes, by electrospray ionization mass spectrometry (ESI-MS) and various spectroscopic techniques. The six alkaloids, including coptisine, columbamine, epiberberine, berberrubine, jateorhizine, and fangchinoline, were selected to explore their interactions with the TC and TTT triplex DNA structures. Berberrubine, fangchinoline, coptisine, columbamine, and epiberberine have preference for TC rich DNA sequences compared to TTT rich DNA triplex based on affinity values in MS. The experimental results from different fragmentation modes in tandem MS, subtractive and hyperchromic effects in UV absorption spectra, fluorescence quenching and enhancement in fluorescence spectra, and strong conformational changes in circular dichroism (CD) hinted that the interaction between isoquinoline alkaloid-TC/TTT DNA had diverse mechanisms including at least two different binding modes: the electrostatic binding and the intercalation binding. Interestingly, columbamine, berberrubine, and fangchinoline can stabilize TTT triplex as inferred from optical thermal melting profiles, while it was not the case in TC triplex. These results provide new insights into binding of isoquinoline alkaloids to pyrimidine motif triplex DNA.

Distinctive carbohydrate profiles of black ginseng revealed by IM-MS combined with PMP labeling and multivariate data analysis.

Despite the widely recognized importance of ginseng carbohydrates, their structural analysis is still challenging due to structural complexity. This study presents the first ion mobility-mass spectrometry (IM-MS) combined with 1-phenyl-3-methyl-5-pyrazolone (PMP) labeling and multivariate data analysis for profiling carbohydrates in the seven ginseng products. 11 carbohydrates were tentatively annotated, including 5 first found in ginseng, and three of them were solely detected in black ginseng (BG) samples, speculated as monosaccharides bearing various groups based on MS2 analysis. Furthermore, 3D profiles of carbohydrates in IM-MS of the samples showed good discrimination between the varieties of ginseng which were classified into two groups utilizing carbohydrate contents by PLS-DA. The big difference between BG and the others may be ascribed to the repeated heating and steaming process for preparation of BG products. Our findings may provide insights into the differences in bioactivity of different ginseng varieties for future research and show a valuable methodology for discovering unknown carbohydrates.

Spectrophotometric Detection of the BRCA1 Gene via Exponential Isothermal Amplification and Hybridization Chain Reaction of Surface-Bound Probes.

In this work, we demonstrated an ultrasensitive approach with a dual-amplification strategy for DNA assay based on isothermal exponential amplification (EXPAR) and the hybridization chain reaction (HCR). In the presence of target DNA, the hairpin probe DNA (HP1) recognized and partially hybridized with the target DNA to form double-stranded structures containing the full recognition sequences for nicking endonuclease and then initiated EXPAR. Under the reaction of EXPAR, a large number of single-stranded DNA (ssDNA) was produced in the circle of nicking, polymerization, and strand displacement. The resulting ssDNA can bind to the surface-bound probe on the well of the microplate and trigger the hybridization chain reaction, resulting in the production of numerous double-stranded DNA concatamers with biotin labeling. In the presence of streptavidin-conjugated horseradish peroxidase (HRP), the amplified signal can be detected by a spectrophotometer via HRP-catalyzed substrate 3,3'5,5'-tetramethylbenzidine (TMB). This proposed dual-amplification method provides a detection limit of 74.48 aM, which also exhibits good linearity ranging from 0.1 fM to 100 pM.

Two-Dimensional Fillers Induced Superior Electrostatic Energy Storage Performance in Trilayered Architecture Nanocomposites.

Dielectric capacitors with ultrahigh power densities and fast charging/discharging rates are of vital relevance in advanced electronic markets. Nevertheless, a tradeoff always exists between breakdown strength and polarization, which are two essential elements determining the energy storage density. Herein, a novel trilayered architecture composite film, which combines outer layers of two-dimensional (2D) BNNS/poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) with high breakdown strength and an intermediate layer made of blended 2D MoS2 nanosheets/P(VDF-HFP) with large polarization, is fabricated using the layer-by-layer casting method. The insulating BNNS with a wide band gap is able to largely alleviate the distortion of the local electric field, thereby suppressing the leakage current and effectively reducing the conductivity loss, while the 2D MoS2 nanosheets act as microcapacitors in the polymer composites, thus significantly increasing the permittivity. A finite element simulation is carried out to further analyze the evolution process of electrical treeing in the experimental breakdown of the polymer nanocomposites. Consequently, the nanocomposites possess an excellent discharged energy density of 25.03 J/cm3 accompanied with a high charging/discharging efficiency of 77.4% at 650 MV/m, which greatly exceeds those of most conventional single-layer films. In addition, the corresponding composites exhibit an outstanding reliability of energy storage performance under continuous cycling. The excellent performances of these polymer-based nanocomposite films could pave a way for widespread applications in advanced capacitors.

96-well plate format in conjunction with ultra-high-performance liquid chromatography coupled to orbitrap mass spectrometry for high-throughput screening protein binders from ginseng.

Conventional strategies for screening of protein binders cannot be used for complicated samples such as ligand libraries created by combinatorial chemistry or from natural product extracts. In the current study, we developed a novel method in a competitive binding configuration for screening protein binders from complicated samples by a combination of streptavidin-coated 96-well plate format in conjunction with ultra-high-performance liquid chromatography coupled with Orbitrap mass spectrometry (UHPLC-Orbitrap-MS). The concanavalin A (Con A) modified 96-well plate and lysozyme modified 96-well plate (as control) were incubated with oligosaccharide standards respectively, and the compounds with the decreased peak areas in experimental group compared to those in the control group were detected as binders by UHPLC-ESI-MS. The factors such as incubation time, incubation temperature, and buffer, which might affect the binding affinity and reproducibility were optimized. The potential of the approach is examined using the extracts of Radix ginseng cruda and American ginseng. The relative binding degrees (RBDs) of the detected disaccharides were relatively high in the extracts of Radix ginseng cruda, and those of the trisaccharides were similar in the extracts of the two kinds of ginseng. To our knowledge, it's the first time to reveal the differences and analogies in lectin peanut agglutinin (PNA)-binding capabilities of oligosaccharides between the extracts of radix ginseng cruda and American ginseng, indicating the efficiency of the method for analysis of complicated samples.

Wearable Carbon Nanotube-Based Biosensors on Gloves for Lactate.

Developing a simple and direct approach for interfacing a sensor and a target analyte is of great interest for fields such as medical diagnosis, threat detection, food quality control, and environmental monitoring. Gloves provide a unique interface for sensing applications. Here, we show for the first time the development of wearable carbon nanotube (CNT)-based amperometric biosensors painted onto gloves as a new sensing platform, used here for the determination of lactate. Three sensor types were studied, configured as: two CNT electrodes; one CNT electrode, and an Ag/AgCl electrode, and two CNT electrodes and an Ag/AgCl electrode. The sensors are constructed by painting the electrodes using CNT or Ag/AgCl inks. By immobilizing lactate oxidase onto the CNT-based working electrodes, the sensors show sensitive detections of lactate. Comparison of sensor performance shows that a combination of CNT and Ag/AgCl is necessary for highly sensitive detection. We anticipate that these findings could open exciting avenues for fundamental studies of wearable bioelectronics, as well as practical applications in fields such as healthcare and defense.

Research on folding diversity in statistical learning methods for RNA secondary structure prediction.

How to improve the prediction accuracy of RNA secondary structure is currently a hot topic. The existing prediction methods for a single sequence do not fully consider the folding diversity which may occur among RNAs with different functions or sources. This paper explores the relationship between folding diversity and prediction accuracy, and puts forward a new method to improve the prediction accuracy of RNA secondary structure. Our research investigates the following: 1. The folding feature based on stochastic context-free grammar is proposed. By using dimension reduction and clustering techniques, some public data sets are analyzed. The results show that there is significant folding diversity among different RNA families. 2. To assign folding rules to RNAs without structural information, a classification method based on production probability is proposed. The experimental results show that the classification method proposed in this paper can effectively classify the RNAs of unknown structure. 3. Based on the existing prediction methods of statistical learning models, an RNA secondary structure prediction framework is proposed, namely "Cluster - Training - Parameter Selection - Prediction". The results show that, with information on folding diversity, prediction accuracy can be significantly improved.

Molecular Weight Determination of Aloe Polysaccharides Using Size Exclusion Chromatography Coupled with Multi-Angle Laser Light Scattering and Refractive Index Detectors.

Background: Size exclusion chromatography (SEC)/refractive index (RI) were used to determine molecular weight (MW) and molecular weight distributions (MWD) of polysaccharides. In aloe product research and quality control, commercially available pullulan and dextran are most commonly employed as calibration standards. Significant difference in the MW and MWD were found in literature when different methods were used. Objectives: This study was to investigate the traditional methods and more recent technologies used to determine the MW and MWD of Aloe vera polysaccharides. Methods: In this study, multi-angle laser light scattering (MALS) detection was studied on three polysaccharides, 1, 2, and 3, that were isolated and purified from A. vera leaf. The chemical structures of 1-3 were characterized as 1, 4-ß-linked glucomannans by monosaccharide composition and glycosidic linkage analysis. Absolute MW and root-mean-square radius were determined by MALS on the isolated aloe polysaccharides. The conditions to obtain reliable results from MALS measurement were examined. Results: MALS analysis demonstrates that the 1, 4-ß-linked glucomannan adopt the conformation of random coils or hard spheres in the analytical environment of a 0.1 M NaCl solution. Non-size exclusion effects and interactions between polysaccharide molecules were also observed in some aloe polysaccharides in the current analysis. The weight-average MW obtained by MALS measurement for 1, 2, and 3 are 55, 129, and 962 kDa, respectively. Comparing the results with SEC/RI calibrated by pullulan and dextran standards, marked differences in the MWD are found. Both overestimated the MW of 1 and 2 by factors of 4.4 and 4.2, and 2.4 and 1.6, when using dextran and pullulan calibration, respectively. Using pullulan calibration underestimated the MW of 3 by a factor of 3.1, but a similar result was obtained from dextran calibration compared to MALS measurement. The two isolated aloe polysaccharides were employed to be broad calibration standards or to be combined with narrow polydispersity pullulan calibration standards. Several aloe samples were tested using the different calibration curves, and the determined MWs were compared with the results obtained by MALS measurement. Conclusions: The results clearly indicated that until true polysaccharide standards become available MW and MWD's will be simply relative to the standards employed and the technologies used.

Chemical Investigation of Major Constituents in Aloe vera Leaves and Several Commercial Aloe Juice Powders.

Background: There are a substantial number of papers in the scientific literature reporting on the chemical composition of the Aloe vera plant. None of these investigations are truly comprehensive nor address the differences in composition that occur through processing variations in fresh leaves and commercially available product forms. Objectives: This work was to analytically examine a range of these forms and compile the findings. Methods: Fresh A. vera leaves and a number of commercial aloe juice powders were investigated for their major chemical constituents. Samples included fresh leaves from China and Mexico, plus commercial powders from different manufacturers made from different plant parts and/or manufacturing processes. The test results include moisture, ash, fiber, protein, lipids, minerals, organic acids, free sugars, and polysaccharides. The analytical methods employed comprise inductively coupled plasma-optical emission spectroscopy for minerals, high-performance anion-exchange chromatography equipped with pulsed amperometric detection for free sugars, HPLC for organic acids, and size exclusion chromatography (SEC)-multi-angle laser light scattering (MALS)-differential refractive index (dRI) for polysaccharide analyses. The absolute MW and MW distribution were determined using MALS measurement. Results: The major constituents of A. vera fresh leaf are fibers, proteins, organic acids, minerals, monosaccharides, and polysaccharides, which accounted for 85-95% of the total composition determined. In the commercial powdered aloe juice samples, four major components-organic acids, minerals, monosaccharides, and polysaccharides-accounted for 78-84% of the total composition. Apart from the four major components, products manufactured by ethanol precipitation contained high amounts of fiber and protein, while the free sugars were removed. In ethanol-precipitated products, the polysaccharide MW was less affected by manufacturing conditions and the concentration of aloe polysaccharides was higher than in products made in the nonethanol manufacturing processes. The overall chemical profiles were found to be consistent, except for the MW and content of polysaccharides in the commercial aloe samples analyzed, which were largely dependent on the types of manufacturing processes employed. Conclusions: This present study provides a comprehensive investigation of the major chemical composition of A. vera leaf and commercially derived products. The use of the SEC combined with MALS and differential RI detectors has proved to be an improved tool for the accurate determination of polysaccharide MW and contents of the various commercially available A. vera products in this study.

A hybrid method for identification of structural domains.

Structural domains in proteins are the basic units to form various proteins. In the protein's evolution and functioning, domains play important roles. But the definition of domain is not yet precisely given, and the update cycle of structural domain databases is long. The automatic algorithms identify domains slowly, while protein entities with great structural complexity are on the rise. Here, we present a method which recognizes the compact and modular segments of polypeptide chains to identify structural domains, and contrast some data sets to illuminate their effect. The method combines support vector machine (SVM) with K-means algorithm. It is faster and more stable than most current algorithms and performs better. It also indicates that when proteins are presented as some Alpha-carbon atoms in 3D space, it is feasible to identify structural domains by the spatially structural properties. We have developed a web-server, which would be helpful in identification of structural domains (http://vis.sculab.org/~huayongpan/cgi-bin/domainAssignment.cgi).

[Differentiation of human promyelocytic leukemia HL-60 cells induced by proanthocyanidin and its mechanism].

This study was purposed to investigate the proliferation, differentiation and apoptosis of human promyelocytic leukemia HL-60 cells induced by proanthocyanidin (PAC). HL-60 cells were incubated with 20 mg/L PAC for 24 h, the cell growth was evaluated by CCK-8 assay. the effect of PAC on HL-60 cells was evaluated and the cells morphology was observed by optical microscopy. Expression of CD14 and CD11b, and cell cycle were analyzed by flow cytometry. The results showed that the growth of HL-60 cells was inhibited after treatment with PAC of different concentration in a dose-dependent manner (P < 0.05). 20 mg/L PAC displayed significant effect on HL-60 cells with inhibition ratio (72.3 ± 1.8)% for 24 h. Microscopy displayed that some cells differentiated to relative mature cells after treating for 48 h. Expression of CD14 increased and the expression of CD11b increased a little after treating with 20 mg/L PAC for 24 h, the ratio of cells in G0/G1 phase increased, but the ratio of cells in S phase decreased. The mRNA and protein expression of P21 gene increased, but the protein expression of CDK4 and Cyclin D1 decreased. It is concluded that PAC may inhibit the proliferation of HL-60 cells in vitro, induces the differentiation of HL-60 cells, and arrests the cells in G0/G1 phase. The possible mechanism may be related to up-regulation of P21 gene expression and down-regulation of the protein expression of CDK4 and Cyclin D1.

[Relation between beta-amyloid peptide-25-35 inducing cell cycle change and apoptosis of serum-deprived PC12 cell].

OBJECTIVE: To study the relation between cell cycle change and apoptosis of serum-deprived PC12 cell, which are induced by beta-amyloid peptide-25-35 (alpha beta(25-35)). METHODS: PC12 cells were synchronized by cultured in deprivation of serum for 24 h and treated with different concentration of alpha beta(25-35) (0-45 micromol/L) for another 24 h,and the cell survival rate was evaluated by MTT assay. The cell apoptosis was analyzed by Hoechst fluorescence staining and DNA agarose gel electrophoresis. The relation between cell cycle redistribution and apoptosis was analyzed by flow cytometry (FCM). RESULTS: alpha beta(25-35) decreased the survival rate of PC12 cells in dose-dependent manner. The typical apoptotic cells were showed by fluorescence staining when treated with 25 micromol/L alpha beta(25-35) for 24 h;the obvious DNA-Ladder was showed by DNA agarose electrophoresis. About 90% PC12 cells were found to arrest on G0/G1 by FCM being deprived serum. Treated with 25 micromol/L alpha beta(25-35) for 8, 16, 24 h, the percent of S phase cells was raised remarkably (P < 0.01) at 8 h, but the percent of S phase cells was declined gradually after treated for 16 h. Meanwhile the apoptotic rate was detected being increased obviously between 16 h and 24 h (P < 0.01), the obvious hypodiploid peak could be observed ahead of G0/G1 phase(Ap). CONCLUSION: alpha beta(25-35) decreases the survival rate of synchronized PC12 cell and induces the synchronized PC12 cells attempting to reenter cell cycle,which appear the apoptotic peak subsequently. This indicates that the cell apoptosis may be related to the abnormal cell cycle distribution induced by alpha beta(25-35), which means there may be a close relationship between cell cycle and apoptosis.