Is exercise good for all? Time- and strain-based work-family conflict and its impacts.

While many people believe that exercise can relieve stress and enrich well-being, it is unclear whether this relationship always holds when employees suffer from work-family conflict (WFC). Drawing on the transactional theory of stress and conservation of resources theory, we examine how exercise moderates the impact of time- and strain-based WFC on employees' vitality at work and, subsequently, employees' subjective well-being. With data collected in multiple waves from a sample in China (N = 243), we found that when employees experienced time-based WFC, strong adherence to exercise did not benefit their vitality as weak adherence to exercise did. However, when employees experienced strain-based work interference with family demands, strong (rather than weak) adherence to exercise benefited their vitality. In addition, the moderating effect of exercise on the relationship between WFC and vitality transited to affect employee job satisfaction.

Click Chemistry Actuated Exponential Amplification Reaction Assisted CRISPR-Cas12a for the Electrochemical Detection of MicroRNAs.

MicroRNAs (miRNAs) play a very important role in biological processes and are used as biomarkers for the detection of a variety of diseases, including neurodegenerative diseases, chronic cardiovascular diseases, and cancers. A sensitive point-of-care (POC) method is crucial for detecting miRNAs. Herein, CRISPR-Cas12a combined with the click chemistry actuated exponential amplification reaction was introduced into an electrochemical biosensor for detecting miRNA-21. The target miRNA-21 initiated the click chemistry-exponential amplification reaction in the electrochemical biosensor to produce numerous nucleic acid fragments, which could stimulate the trans-cleavage ability of CRISPR-Cas12a to cleave hairpin DNA electrochemical reporters immobilized on the electrode surface. Under optimal conditions, the minimum detection limit for this electrochemical biosensor was as low as 1 fM. Thus, the proposed electrochemical biosensor allows sensitive and efficient miRNA detection and could be a potential analysis tool for POC test and field molecular diagnostics.

Ultrasensitive, rapid, and highly specific detection of microRNAs based on PER-CRISPR/CAS.

Abnormal microRNA (miRNA) expression levels are confirmed as diagnostic biomarkers of the emergence and development of diseases. In this study, we developed a fluorescence biosensor for detecting miRNAs based on double amplification reactions with the primer exchange reaction (PER) and CRISPR/Cas12a. In the absence of target miRNA-21, PER hairpins remained locked by the protector strands and the primers did not extend. In the presence of target miRNA-21, the miRNA-21 bound to the guard sequence and exposed primer binding sites. Also, the closed PER hairpin was unlocked to specifically extend primers into single-stranded DNA (ssDNA) of unequal lengths. These ssDNAs of unequal lengths could activate the cleavage of a reporter by Cas12a, leading to an increase in detectable fluorescence signals. A large number of short nucleic acid fragments were amplified by PER-CRISPR multiple cycle cleavage fluorescent probes. Based on PER-combined CRISPR/Cas12a established dual signal amplification method was characterized by a low limit of detection of 10fM. The fluorescent biosensor for miRNA detection had the advantages of low detection cost, simple operation, and mobility, providing a very promising platform for the point-of-care testing of miRNA-21.

Electrochemical biosensor for detecting pathogenic bacteria based on a hybridization chain reaction and CRISPR-Cas12a.

In this study, Lba Cas12a (Cpf1) as one of the CRISPR systems from Lachnospiraceae bacterium was coupled with a hybridization chain reaction (HCR) to develop an electrochemical biosensor for detecting the pathogenic bacterium, Salmonella typhimurium. Autonomous cross-opening of functional DNA hairpin structures of HCR yielded polymer double-stranded DNA wires consisting of numerous single-stranded DNAs, which initiated the trans-cleavage activity of CRISPR-Cas12a to indiscriminately cleave random single-stranded DNA labeling electrochemical tags on the surface of the electrode. It led to a variation in the electron transfer of electrochemical tags. The polymer double-stranded DNA of HCR was immobilized on dynabeads (DBs) via the S. typhimurium aptamer and released from DBs. The established method could selectively and sensitively quantify S. typhimurium in samples with detection limits of 20 CFU/mL. Our study provides a novel insight for exploring universal analytical methods for pathogenic bacteria based on CRISPR-Cas12a coupled with HCR.

An electrochemical biosensor for the detection of pathogenic bacteria based on dual signal amplification of Cu3(PO4)2-mediated click chemistry and DNAzymes.

A novel electrochemical biosensor for detecting pathogenic bacteria was designed based on specific magnetic separation and highly sensitive click chemistry. Instead of enzyme-antibody conjugates, organic-inorganic hybrid nanoflowers [concanavalin A (Con A)-Cu3(PO4)2] were used as the signal probe of the sandwich structure. The inorganic component, the copper ions of hybrid nanoflowers, was first used to amplify signal transduction for enzyme-free detection. Sodium ascorbate could dissolve Cu3(PO4)2 of the signal probe to produce Cu2+, which was subsequently converted to Cu+, triggering the Cu+-catalyzed alkyne-azide cycloaddition (CuAAC) reaction between azide-functionalized ssDNA (a fragment of the DNAzyme-containing sequence) and alkyne-functionalized ssDNA immobilized onto the electrode surface. As a result, the DNAzyme was immobilized onto the gold electrode, which produced a positive and stable electrical signal. An exceptional linear relationship was observed between the electrical signal and the concentration of Salmonella typhimurium (101-107 CFU mL-1) with a detection limit of 10 CFU mL-1. The developed electrochemical biosensor based on dual signal amplification of Cu3(PO4)2-mediated click chemistry and DNAzymes exhibited good results in detecting S. typhimurium in milk samples.

Visual assay of Escherichia coli O157:H7 based on an isothermal strand displacement and hybrid chain reaction amplification strategy.

Here, we describe a simple, sensitive, and enzyme-free method for visual point-of-care detection of 16S rRNA of Escherichia coli O157:H7 based on an isothermal strand displacement-hybrid chain reaction (ISD-HCR) and lateral flow strip (LFS). In this study, the secondary structure of 16S rRNA of E. coli O157:H7 was unwound by two helper oligonucleotides to expose the single-strand-specific nucleic acid sequence. The free specific sequence promoted the toehold-mediated strand displacement reaction to output a large number of FITC-labeled single-stranded DNA probes (capture probe [CP]). The 3'-end sequence of the reporter probe propagated a chain reaction of hybridization events between the two hairpin probes modified with biotin to form long nicked DNA polymers with multiple biotins (RP-HCR complexes); the free CP and RP-HCR complexes then form CP/RP-HCR complexes. The biotin-labeled double-stranded DNA CP/RP-HCR polymers then introduced numerous streptavidin (SA)-labeled gold nanoparticles (AuNPs) on the LFS. The accumulation of AuNPs produced a characteristic red band, which enabled visual detection of changes in the signal of 16S rRNA of E. coli O157:H7. The current approach could detect E. coli O157:H7 at concentrations as low as 102 CFU mL-1 without instrumentation. This approach thus provides a simple, sensitive, and low-cost tool for point-of-care detection of pathogenic bacteria, especially in resource-limited countries.

Ferrocene-functionalized nanocomposites as signal amplification probes for electrochemical immunoassay of Salmonella typhimurium.

An electrochemical immunosensor based on ferrocene (Fc)-functionalized nanocomposites was fabricated as an efficient electroactive signal probe to amplify electrochemical signals for Salmonella typhimurium detection. The electrochemical signal amplification probe was constructed by encapsulating ferrocene into S. typhimurium-specific antimicrobial peptides Magainin I (MI)-Cu3(PO4)2 organic-inorganic nanocomposites (Fc@MI) through a one-step process. Magnetic beads (MBs) coupled with antibody were used as capture ingredient for target magnetic separation, and Fc@MI nanoparticles were used as signal labels in the immunoassays. The sandwich of MBs-target-Fc@MI assay was performed using a screen-printed carbon electrode as transducer surface. The immunosensor platform presents a low limit of detection (LOD) of 3 CFU·mL-1 and a linear range from 10 to 107 CFU·mL-1, with good specificity and precision, and was successfully applied for S. typhimurium detection in milk. Graphical abstract One-pot process antimicrobial peptides Magainin I-Cu3(PO4)2 organic-inorganic nanocomposites (Fc@MI) were used as ideal electrochemical signal label, integrating both essential functions of biological recognition and signal amplification. Screen-printed carbon electrode (SPCE) was used as the electrochemical system for Salmonella typhimurium detection.

A sensitive biosensor for determination of pathogenic bacteria using aldehyde dehydrogenase signaling system.

Aldehyde dehydrogenase (ALDH) was first developed as an enzymatic signaling system of a biosensor for sensitive point-of-care detection of pathogenic bacteria. ALDH and specific aptamers to Salmonella typhimurium (S. typhimurium), as organic components, were embedded in organic-inorganic nanocomposites as a biosensor signal label, integrating the functions of signal amplification and target recognition. The biosensing mechanism is based on the fact that ALDH can catalyze rapid oxidation of acetaldehyde into acetic acid, resulting in pH change with portable pH meter readout. The altered pH exhibited a linear relationship with the logarithm of S. typhimurium from 102 to 108 CFU/mL and detection limit of 46 CFU/mL. Thus, the proposed biosensor has potential application in the diagnosis of pathogenic bacteria.

[Tending of wild Heterosmilax yunnanensis].

To minimize the predatory harvest of Heterosmilax yunnanensis and maintain the sustainable utilization of its resources, a study on the tending technology of wild H. yunnanensis was carried out. The results showed that the tuber tending model had a higher seed emergence rate, shorter growth period and easier control of male and female ratios than other tending models; by removing shrubs, topping, bending pruning, controlling insects and pests and other effective technical measures, the growth period of H. yunnanensis was shortened; the average annual net income of the tending area was 1 086 yuan/mu (1 mu≈666.67 m²), which was 86.9% higher than before. This study was conducive to increasing the yield and quality of H. yunnanensis in Karst landform area, and instructive for the tending of other wild traditional Chinese medicinal herbs in this area.

A Cross-Level Study on Family Involvement and Job Satisfaction.

This study aims to explore how various dynamics of working couples' family involvement shape their job satisfaction. With a sample collected from primary school teachers and spouses in China (n = 236), we use polynomial regression, response surface method, and multilevel structural equation model to capture the various dynamics of working couples' family involvement. We found that (1) high-high spouses' family involvement has a negative impact on individual job satisfaction, and low-low spouses' family involvement is positively related to individual job satisfaction. (2) High-high spouses' family involvement benefits the creation of positive affect at the family level, which decreases family-to-work conflict and mitigates its negative impacts on individual job satisfaction. (3) Working couple's perceived work-to-family enhancement moderates the relationship between spouses' family involvement and positive affect at the family level. This study extends our understanding of family-to-work spillover effects from the viewpoint of dynamic interaction between spouses at the cross level.