Search

In order to investigate the effect of long-term consumption of yak milk on the intestinal flora and metabolism and to explore the correlation between acclimation to monodiet and yak milk intake in high-altitude pastoral areas, this study used metagenomics and metabolomics to evaluate the gut microbial community structure and metabolites of mice fed yak milk or Holstein cow milk. Results showed that compared with the control group (normal saline solution), at the phylum level, ingestion of yak milk improved the relative abundance of Actinobacteria (33.27%), Bacteroidetes (24.31%) and Verrucomicrobia (11.08%), while ingestion of Holstein cow milk increased the relative abundance of Firmicutes (43.74%) and Bacteroidetes (24.75%). At the genus level, yak milk consumption increased the relative abundance of Ackermania (11.80%), Bacteroides (6.09%) and Limosilactobacillus (4.77%), while Holstein cow milk consumption increased the relative abundance of Lactobacillus (28.62%), Duncaniella (6.15%) and Limosilactobacillus (6.49%). Both yak and Holstein cow milk up-regulated carbohydrate and nucleotide metabolism. Furthermore, yak milk significantly up-regulated amino acid metabolism, cofactor and vitamin metabolism, energy metabolism, the biosynthesis of secondary metabolites, and the biosynthesis and metabolism of peptidoglycan. Metabolomics revealed that yak milk increased the contents of metabolites such as VB1, (+/-) 12 (13)-DiHOME, coenzyme Q2 and sulfonymethazine, as well as steroid hormone biosynthesis, cofactor biosynthesis, 2-oxyarboxylate metabolism, VB6 metabolism and phenylalanine metabolism in mice. Investigation of intestinal tissue morphology showed that the intestinal wall became thicker with increasing diversity and richness of the gut microbiota and the intestinal villi became longer and denser without deformity or breakage. In conclusion, yak milk has a positive effect on the intestinal flora and metabolism in mice, and this study provides a scientific basis for further development and utilization of yak milk.

To investigate the inhibitory mechanism of small peptides on carbohydrate digestion, α-amylase and α-glucosidase inhibitory fractions from the water extract and the gastropancreatic digest of dry-cured ham muscle of Wanzhe spotted pigs were separated, purified, identified, and screened for peptide sequences. And the quantum chemical calculation was used to calculate structural and charge parameters including the distribution and energy of the frontier orbitals, electrostatic charge distribution and bond length, in order to speculate the active sites. It was found that the particle size of ham muscle decreased and its hypoglycemic activity increased after proteolysis. Two (S-I and S-II) and three fractions (WY-I, WY-II and WY-III) were obtained from the water extract and the digest after Sephadex column chromatography, respectively. Using mass spectrometry, 104 peptide sequences consisting of 8–24 amino acids were identified from fraction WY-II and five sequences with Peptide Ranker scores greater than 0.7 were selected. The highest occupied orbitals of the five sequences were mainly distributed in the guanidine groups of arginine and the groups close to the amino-terminal end, while the lowest unoccupied orbitals were in the carboxyl terminals and nearby groups. Sequences with lower ΔEL-H values, GPMGPSGPR, LGFGGPSGPNAGR and APAPAPAPAPPK, might be more active. According to Coulomb’s law, the active sites of these three peptides were located at –C106H108 of arginine, –C10H12 of leucine and –C176H177 of lysine, respectively. This study could provide theoretical support for understanding the blood glucose-regulating mechanism of peptides and the nutritional value of local pig breeds.

ObjectiveTo analyze the mental health status and its influencing factors in middle school students under the regular prevention and control of COVID-19， so as to provide references for the intervention and management of their mental health problems.MethodsFrom March 7 to 21， 2021， a stratified random sampling method was used to select 19 352 students from 17 schools in 3 districts and 9 counties of Linyi City， Shandong Province. Basic data were collected through a self-designed questionnaire. All students completed the Symptom Checklist 90 （SCL-90） to assess their mental health status. Then the factors affecting the mental health status of middle school students were screened using independent sample t-test， one-way ANOVA test and multiple stepwise regression analysis.Results① A total of 6 350 （32.81%） middle school students were found to have mental health problems. ② Each SCL-90 factor score and total average score yielded statistical difference among middle school students of different genders， relationships with classmate， closeness to friends， concerns about the epidemic， and pressure exerted by schoolwork （P

This research aimed to study the bacterial community, free amino acid and fatty acid composition in featured dry fermented dairy products from some major pastoral areas of China and to analyze the correlation between bacterial community and free amino acid and fatty acid composition. The V4–V5 region of the bacterial 16S rDNA gene from Suannai Geda from Xinjiang, Qula from Tibet, Naizhazi from Inner Mongolia and milk fan from Yunnan was sequenced by high-throughput sequencing. The contents of fatty acids and free amino acids in these dairy products were determined by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (LC), respectively. Finally, the correlation of bacterial community with α diversity, fatty acids and free amino acids was evaluated by redundancy analysis (RDA). High-throughput sequencing results showed that a total of 2 421 338 reads were obtained from these dry fermented dairy samples, of which 1 871 524 were clean reads. The bacterial Chao1 and Shannon indexes in milk fan were significantly higher than those in the other three dairy products. The bacterial community compositions in the four dairy products were significantly different, but Firmicutes was dominant in all these products, among which the relative abundance of Firmicutes in Suannai Geda was the highest. The relative abundance of Proteobacteria in Qula was the highest. At the genus level, the bacterial community compositions in the four dairy products were dominated by Lactococcus or Lactobacillus. The contents of 16 fatty acids in milk fan were higher than those in the other three products. A total of 24 free amino acids were detected, among which Suannai Geda contained the largest number (24) of free amino acids, and the contents of most free amino acids in Suannai Geda were higher than those in the other three products. Redundancy analysis showed that alanine was correlated with Acetobacter, Lactobacillus and Streptococcus, and acetic acid and butyric acid were correlated with Acinetobacter. The results of this study may provide a theoretical basis for the industrial production of traditional dry fermented dairy products in different provinces.

Underwater object detection is a challenging task in the process of marine exploration and development. Addressing the issue of poor underwater target detection performance in existing algorithms due to problems such as low visibility and color distortion in underwater images, an improved YOLOv7 underwater target detection algorithm is proposed with the aim of improving underwater object detection performance. Firstly, a multi-information flow fusion attention mechanism (spatial group-wise coordinated competitive attention, SGCA) is designed to solve the problem of feature loss caused by the loss of global context information of the image in the convolution process. It improves the detection accuracy of the model in the case of image blur. Additionally, the switchable atrous convolution (SAConv) module is used to replace the 3×3 convolution module in the ELAN structure to enhance the feature extraction capability of the backbone network. Secondly, Wise-IoU is used as the loss function in the prediction part, which obtains more accurate detection results by balancing model training outcomes on images of varying quality. Finally, an underwater image enhancement method based on dark channel prior (DCP) and depth transmission maps is employed to enhance the images in the underwater dataset. Experimental results show that the improved algorithm achieves a mAP of 87.3% on the selfbuilt underwater object detection dataset, which is 3.4 percengtage points higher than that of the original YOLOv7 algorithm. On the enhanced underwater image dataset, mAP is 87.1%, increases 2.1 percentage points. Therefore, the proposed approach exhibits superior performance in underwater object detection tasks. [ABSTRACT FROM AUTHOR]

Objective To study on the expression of forkhead box D1 (FOXD1) in pancreatic cancer and the mechanism of invasion and metastasis of pancreatic cancer through FOXD1 via the extracellular signal-regulated kinase (ERK) pathway. Methods We searched the database of expression of FOXD1 in both pancreatic cancer and normal pancreatic tissue from the Cancer Genome Atlas and analyzed the difference in expression of FOXD1. Expression of FOXD1 mRNA in pancreatic tissue of 15 cases with pancreatic cancer was detected using polymerase chain reaction. Expression of FOXD1 in pancreatic cancer cell lines was analyzed using Western Blot. The effect of FOXD1 knockdown on the expression of proteins associated with epithelial mesenchymal transition(EMT) was investigated using Western Blot. The effect of FOXD1 knockdown on the proliferation and invasion of pancreatic cancer cell lines were tested by cell counting kit-8 assay and Transwell assay. Results FOXD1 was highly expressed in pancreatic cancer tissues and cell lines. Knockdown of FOXD1 attenuated the proliferation and invasion of pancreatic cancer cell lines and enhanced expression of EMT associa-ted proteins including epithelial cadherin and ERK while attenuated expression of neuronal cadherin and phosphorylated ERK. Conclusions FOXD1 would be the oncogene of pancreatic cancer by promoting invasion and metastasis of pancrea-tic cancer via ERK pathway.

BACKGROUND: Fracture fixation and surgical procedures have a very important impact on the final outcome of fracture healing, but the adverse outcome of fracture healing is the result of the combined action of surgical procedures and a series of four-dimensional space events. OBJECTIVE: To explore the four-dimensional space events in fracture healing. METHODS: China National Knowledge Infrastructure and Medline were retrieved, with the key words of "fracture healing, femoral fracture, stress shielding, fracture and blood flow" in Chinese and English. Retrieval of relatively macroscopic factual descriptions corresponds to the four-dimensional space events of fracture healing process, including logically supported and refuted evidence. Combined with literature review, the main four-dimensional space events after fracture fixation were analyzed. RESULTS AND CONCLUSION: The main four-dimensional space events after fracture fixation include blood flow tides, mechanical and biological impulses, grinding disc effect of small gap in hard tissue, stress shielding effect and four-dimensional space drift effect of internal fixation material. Fractures and surgical trauma are accompanied by months of super-compensatory blood flow tides, so there is no ischemia in the macro-level after fracture surgery, but the grinding disc effect will occur in the small gap of hard tissue under unstable condition, resulting in contusion injury and micro-ischemia in the fracture gap. Stress shielding effect caused by too strong fixation is an important reason for refracture after internal fixation removal and bone atrophy and thinning after internal fixation. The small axial drift of plate fixation screw may have important theoretical significance. It has "intelligent' axial dynamic effect, which can make the stress shared by plate gradually decrease with the healing of fracture. Discussing the four-dimensional space events of fracture healing will provide basic logic for the regulation of fracture healing and distraction osteogenesis. [ABSTRACT FROM AUTHOR]

Drilling in Luojia block and Qiaozhuang area of Shengli Oilfiled has certain risk because of the crack development of oil and mud shale. Using oil-base drilling fluid could solve the problem well. At present, oil-base drilling fluid has been applied in several wells in these regions. In this pa per, the applications of oil-base drilling fluid are summarized. Some problems existing in field application are concluded and analyzed, and some countermeasures are proposed. [ABSTRACT FROM AUTHOR]

Sodium dodecyl sulfate capillary electrophoresis has become the mainstream method for purity analysis of monoclonal antibodies because of its advantages of fast and high resolution. Sample preparation has a significant impact on the purity detection of non-reduced monoclonal antibodies. In order to optimize sample preparation, the purity of monoclonal antibodies of different types and batches in sample buffers with iodoacetamide and N-ethyl maleimide as sulfhydryl sealants and at pH 6.0-9.0 was investigated. It was found that in the two types of sulfhydryl sealants, the high pH sample buffer could affect the sealing effect of the sulfhydryl sealant and produce more antibody fragments. Conversely, under the low pH condition, the antibody fragments were fewer and the purities of monoclonal antibodies were higher. Therefore, the sample buffer with pH 6.0 is the optimal preparation condition for the purity detection of non-reduced monoclonal antibodies.

Objective: To examine the growth activity and osteogenic differentiation of bone mesenchymal stem cells (BMSCs) in rats with Type 2 diabetes mellitus (T2DM) as well as the expression level of Dickkopf-1 (DKK-1) in bone marrow, and to explore the relationship between the osteogenic activity of BMSCs and the expression of DKK-1.
 Methods: The BMSCs were isolated from T2DM rats and were cultured in vitro. The BMSCs were divided into a T2DM group and a control group. The proliferation of BMSCs was detected by cell counting kit-8 (CCK8). Apoptosis rate was detected by annexin V- fluorescein isothiocyanate (FITC)/propidium iodide (PI) double staining. In the osteogenic induction phase, the expression level of alkaline phosphatase (ALP) in BMSCs was detected by ALP staining and ALP activity assay kit. The osteogenic differentiation of BMSCs was analyzed by alizarin red staining and mineralized nodule quantification. In addition, the expression of Runx2 and DKK-1 in BMSCs was detected by qRT-PCR.
 Results: Compared with the control group, the proliferation of BMSCs was decreased and the apoptosis was increased in the T2DM group (both P<0.01). In the osteogenic induction process of BMSCs, the expression of ALP significantly decreased, the formation of calcium nodules reduced, and the expression of osteoblast transcription factor Runx2 was down-regulated in the T2DM group compared with those in the control group (all P<0.01). The levels of DKK-1 protein and mRNA were up-regulated in the T2DM group, which were higher than those in the control group (both P<0.01). The levels of DKK-1 protein and mRNA were related to the increase of Runx2 (both P<0.01).
 Conclusion: The growth activity of BMSCs and the potential of osteogenic differentiation are attenuated in the T2DM rats, which may be related to the increase of DKK-1 expression in BMSCs.