Responses of soil enzyme activity to freeze-thaw alternation in Greater Khingan Mountains, China.

We examined the effects of freeze-thaw cycles (0, 1, 3, 5, 7, 15 cycles) on the activities of urease, invertase, and proteinase in the different layers of the soil under the four typical stands in the cold temperate zone, i.e., Pinus pumila stand, Rhododendron-Betula platyphylla stand, Rhododendron-Larix gmelinii stand, Ledum-Larix gmelinii stand, with the indoor freeze-thaw simulation culture method being used. The relationship between soil enzyme activity and multiple physicochemical variables was analyzed during freeze-thaw alternation. The results showed that the activity of soil urease was firstly increased and then inhibited during freeze-thaw alternation. After freeze-thaw, urease activity did not differ from that without freeze-thaw. Invertase activity was firstly inhibited and then increased during freeze-thaw alternation, and was significantly increased by 8.5%-40.3% after freeze-thaw. Proteinase activity was firstly increased and then inhibited during freeze-thaw alternation, and was significantly decreased by 13.8%-68.9% after freeze-thaw. After freezing and thawing, there was significant positive correlation between urease activity and ammonium nitrogen and soil water content in Ledum-L. gmelinii stand and P. pumila stand, respectively, and proteinase activity had significant negative correlation with inorganic nitrogen concentration in P. pumila stand, Rhododendron-B. platyphylla stand, and Ledum-L. gmelinii stand. Invertase activity had significant positive correlation with organic matter in Rhododendron-L. gmelinii stand and Ledum-L. gmelinii stand.

The Relationship Between Mindfulness, Fatigue, and Perceived Symptoms Among Frontline Nurses Who Performed Nucleic Acid Sample Collection During the COVID-19 in China: A Cross-Sectional Study.

Objective: Given the immense stress faced by medical staff during the COVID-19 pandemic, this study aimed to evaluate the relationship between mindful attention awareness, fatigue, and perceived symptoms among frontline nurses who performed nucleic acid sample collection during the COVID-19 pandemic, to reduce their fatigue and help them cope with perceived uncomfortable symptoms. Methods: A convenience sampling method was used to survey nurses who travelled to Hainan for nucleic acid sampling in August 2022 using an online (WeChat) questionnaire. A total of 514 frontline nurses who performed nucleic acid tests completed the questionnaire. The questionnaire covered basic demographic information, Mindful Attention Awareness Scale (MAAS) ratings, and Fatigue Severity Scale (FSS) ratings. Spearman correlation analysis was used to separate the relationship between MASS and FSS, and univariate and multivariate factor analyses were used to explore the relevant influences contributing to the occurrence of fatigue. Results: A total of 514 individuals completed the survey,93.97% (n=483) were female, mean age was 31.15 ± 5.7, MASS score was 69.01 ± 13.53, and 296 (57.59%) nurses experienced symptoms of fatigue during the auxiliary period. Spearman correlation analysis showed that FSS was associated with MASS. Multifactorial analysis showed that sex, age, marital status, fertility status, years of work, adaptation to dietary habits, hidrorrhea, and MAAS scores affected the presence of fatigue symptoms among the medical staff in Hainan (P<0.05). Conclusion: The psychological status of frontline nurses undergoing nucleic acid testing during the pandemic was poor, and the appearance of fatigue symptoms could be effectively reduced by increasing levels of positive thinking among medical staff to help them cope with public health emergencies.

[Potential turnover differences of exogenous alanine in soils of typical forests in the Xiaoxing'an Mountains, China]. / å°å ´å®‰å²­å ¸åž‹æ£®æž—åœŸå£¤ä¸­å¤–æºä¸™æ°¨é ¸çš„æ½œåœ¨å‘¨è½¬å·®å¼‚.

Taking five typical forests (Betula platyphylla forest, Quercus mongolica forest, B. platyphylla + Pinus koraiensis + Acer mono mixed forest, P. koraiensis forest, and Larix olgensis forest) in Xiaoxing'an Mountains as test objects, we investigated the effects of forest types (broadleaved forest, mixed forest, and coniferous forest) and soil layers (0-10 cm, 10-20 cm, 20-30 cm) on the turnover of exogenous alanine. The results showed that the turnover of soil exogenous alanine varied across different forest types, with significant difference in time and profile. The turnover rate was the highest in the broadleaved forest, followed by the mixed forest, and the lowest in the coniferous forest, with the half-life being 2.6-4.2, 3.6-5.5, and 4.3-7.0 h, respectively. With increasing soil depth, the potential turnover rate of exogenous alanine decreased, the half-life became longer, and soil adsorption of alanine weakened. With the addition of exogenous alanine, the content of ammonium and nitrate significantly increased, with the former being increased by 83.8%-95.3%, 80.9%-94.6% and 73.7%-93.2%, and the latter being increased by 82.9%-94.7%, 82.3%-93.8% and 78.1%-92.5% in the broadleaved forest, mixed forest, and coniferous forest, respectively. The net ammoniation and nitrification rates increased sharply at first and then decreased slowly, which were both positive. Soil layer and forest type as well as their interaction significantly affected the turnover, half-life, ammoniation, and nitrification of exogenous alanine.

Relationship between the red cell distribution width-to-platelet ratio and in-hospital mortality among critically ill patients with acute myocardial infarction: a retrospective analysis of the MIMIC-IV database.

OBJECTIVES: We aimed to investigate the association between red cell distribution width-to-platelet ratio (RPR), and in-hospital mortality in critically ill patients with acute myocardial infarction (AMI). DESIGN: A retrospective cohort study. SETTING: Data were collected from the Medical Information Mart for Intensive Care database (MIMIC-IV) consisting of critically ill participants between 2008 and 2019 at the Beth Israel Deaconess Medical Centre in Boston. PARTICIPANTS: A total of 5067 patients with AMI were enrolled from the MIMIC-IV database. PRIMARY AND SECONDARY OUTCOME: In-hospital mortality. RESULTS: A total of 4034 patients survived, while 1033 died. In a multiple regression analysis adjusted for age, weight and ethnicity, RPR also showed a positive correlation with in-hospital mortality (HR 1.91, 95% CI 1.42 to 2.56, p<0.0001). Moreover, after adjusting for additional confounding factors, obvious changes were observed (HR 1.63, 95% CI 1.03 to 2.57, p=0.0357). In model 2, the high ratio quartile remained positively associated with hospital mortality compared with the low ratio quartile (HR 1.20, 95% CI 1.01 to 1. 43), with a p-value trend of 0.0177. Subgroup analyses showed no significant effect modifications on the association between RPR and in-hospital mortality in the different AMI groups (p>0.05). CONCLUSION: RPR is an independent predictor of in-hospital mortality in critically ill patients with AMI.

[Cloning and functional verification of U6 and 7SK promoter of small RNA from Bama mini-pig in Guangxi].

To investigate the functions of U6 and 7SK of Bama mini-pig and produce Bama mini-pig with silenced GGTA1 gene, the siRNA promoters U6 and 7SK were cloned, ligated into pMD18-shEGFP, and co-transfected with PEGFP- N1 into PK-15 kidney cells of pigs to be used in RNAi experiments. The functions of the two promoters in pig cells were verified using pMD18-hU6-shEGFP as the positive control, pMD18-shEGFP vector without promoter as the negative control, PEGFP-N1 as the first blank control, ddH2O in replacement of the plasmid as the second blank control. The results showed that the lengths of U6 and 7SK in Bama mini-pig were 553 bp and 437 bp, respectively. Vectors pMD18-pU6- shEGFP and pMD18-p7SK-shEGFP were constructed and transfected into PK-15 cells from pigs. Promoters pU6 and p7SK proved to express high levels of siRNA activity and can be used in the experiment of silencing α-1,3galactosyltransferase gene.

[cDNA cloning and protein structure analysis of growth hormone from Clarias lazera].

Total RNA was isolated from pituitary gland of Clarias lazera, and the cDNA encoding growth hormone (GH) protein was amplified and cloned by reverse transcription polymerase chain reaction (RT-PCR). The open reading frame (ORF) of cDNA is of 603 nt which encodes GH precursor consisted of a signal peptide with 22 amino acid residues and a mature peptide with 178 amino acid residues. Sequence alignment indicated that the amino acid sequence homology approached to 95.8% between C. lazera and other 6 species of Siluriforms catfish. Secondary structure assessment showed that the GH protein contained different structural regions of alpha-helix, beta-sheet, beta-turn and random coil, among which alpha-helix has main proportion. Antigenicity analysis indicates that there exist 4 domains in amino acid sequence where B cell dominant epitopes could form. Summarily, the structure characteristics of C. lazera GH should provide a great benefit in its modification into recombinant vaccine or monoclonal antibody for future application.

[Intraspecific DNA sequence polymorphism and genetic markers in the mitochondrial CO I gene from three populations of Macrobrachium rosenbergii].

The mitochondrial COI gene was PCR amplified and sequenced from 17 samples obtained from three populations of Macrobrachium rosenbergii (F1 of the Burma wildtype population, Jiangsu cultured population and F2 of the Guangxi breeding population). A 498-bp long partial gene segment was acquired and used to study the genetic diversity among the three populations. Results indicated that the COI gene locus was relatively more polymorphic in the F1 of Burma wildtype population, while the polymorphism in Jiangsu cultured population and Guangxi breeding population were very poor. A total of 10 polymorphic sites and 5 haplotypes were found in the sequences of the 17 samples. The average nucleotide divergence in the three populations was 0.88%0.07% and 0 respectively. The UPGMA phylogenetic tree suggested that F2 of the Guangxi breeding population and Jiangsu cultured population were closest genetically, and their haplotypes could be gathered together to a genetic branch while F1 of the Burma wildtype population diverged and could form another relatively independent branch. For these distinct nucleotide differences, COI gene could be suitable as a genetic marker for distinguishing these two branches of the Macrobrachium rosenbergii population.

[Effect of NO3- supply on lateral root growth in maize plants].

Growth of lateral roots is regulated by both environmental factors and nitrate (NO(-)(3)) content of the plant. The mechanism involved is not clearly understood. Two maize (Zea mays L.) inbred lines (478 and Wu312) were used to study the effect of different nitrate supply on lateral root (LR) growth by a whole plants agar culture. The results showed that increasing NO(-)(3)concentration in nutrient solution from 0.01 to 1.0 mmol/L significantly increased the LR length and root biomass. Lateral root density changed little with NO(-)(3) increase up to 5x10(-3) mol/L (for Wu312) - 10x10(-3) mol/L (for 478), then decreased significantly with increasing NO(-)(3). The inhibitory effect of high NO(-)(3) on root growth was weaker in 478 than in Wu312. The growth of lateral roots in Wu312 was completely inhibited by NO(-)(3) at a concentration of 10x10(-3) mol/L, whereas LR density of 478 could reach 30% (axial) and 50% (radicle) of its maximum even at NO(-)(3) 20x10(-3) mol/L. Both the shoot total N and shoot nitrate content increased with increasing NO(-)(3) level. They had similar mathematic functions with shoot/root ratio (Exponential Decay), LR density (Gaussian) and LR length (Parabola). When shoot N content exceed about 1.6 mol/kg and NO(-)(3) content exceed 0.22 mol/kg, shoot/root ratio increased rapidly; when the shoot N content exceed about 1.5 and NO(-)(3) exceed 0.16 mol/kg, LR densities began to decrease; when shoot N content reached about 1 mol/kg and NO(-)(3) content reached 0.10 mol/kg, the LR lengths began to decrease. The possible relationship between shoot NO(-)(3) content and lateral root growth was discussed.