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1.
DNA Cell Biol ; 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-35007429

RESUMO

Hair follicle stem cells (HFSCs) play a significant role in hair development. miR-1 has been reported as an important regulatory factor that affects hair follicle growth and development, but its regulatory mechanism on HFSC development remains unknown. In this study, the molecular mechanism of miR-1 in regulating HFSC proliferation and differentiation was investigated. High-throughput RNA-seq and integrated analysis were performed to identify differentially transcribed mRNAs and microRNAs (miRNAs) in HFSCs co-cultured with dermal papilla cells (named dHFSCs) and control HFSCs. We then determined the molecular function of miR-1 in HFSCs. Compared with HFSCs, 13 differentially transcribed miRNAs were identified in dHFSCs. The in vitro results indicated that the overtranscription of miR-1 inhibited HFSC proliferation, but enhanced HFSC differentiation by targeting IGF1R and LEF1 genes. This study provides new insights into the molecular mechanisms of HFSC development. Approval ID (2014ZX08008-002).

2.
Bioengineered ; 13(1): 1235-1248, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34983299

RESUMO

To date, several different types of synthetic genetic switches, including riboregulators, riboswitches, and toehold switches, have been developed to construct AND, OR, NOT, NAND, NOR, and NOT IMPLICATION (NIMP) gates. The logic gate can integrate multiple input signals following a set of algorithms and generate a response only if strictly defined conditions are met. However, there are still some logic gates that have not been implemented but are necessary to build complex genetic circuits. Here, based on the toehold switches and three-way-junction (3WJ) repressors, we designed two novel biological Boolean logic gates of IMPLICATION (IMP) and XOR. Subsequently, the outputs of these two logic gates were characterized by fluorescence analysis, indicating that they can achieve the truth tables of logical gates. Furthermore, the fluorescence intensity under the logical TRUE condition was significantly higher than under the logical FALSE condition, suggesting the high dynamic range of the ON/OFF ratios. Because of the programmability of synthetic RNA switches, the constructed RNA logic gates could serve as elementary units to build a versatile and powerful platform for translational regulation and RNA-based biological computation.

3.
Int J Mach Learn Cybern ; : 1-11, 2022 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-35035595

RESUMO

Misinformation has become a frightening specter of society, especially fake news that concerning Covid-19. It massively spreads on the Internet, and then induces misunderstandings of information to the national and global communities during the pandemic. Detecting massive misinformation on the Internet is crucial and challenging because humans have struggled against this phenomenon for a long time. Our research concerns detecting fake news related to covid-19 using augmentation [random deletion (RD), random insertion (RI), random swap (RS), synonym replacement (SR)] and several graph neural network [graph convolutional network (GCN), graph attention network (GAT), and GraphSAGE (SAmple and aggreGatE)] model. We constructed nodes and edges in the graph, word-word node, and word-document node to graph neural network. Then, we tested those models in different amounts of sample training data to obtain accuracy for each model and compared them. For our fake news detection task, we found training accuracy steadily increasing for GCN, GAT, and SAGE models from the beginning to the end of the epochs. This result proved that the performance of GNN, whether GCN, GAT, or SAGE gained an entirely insignificant difference precision result.

4.
Food Chem ; 366: 130543, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34284193

RESUMO

Differences in Mixolab measurements of dough processing were examined using, as a base, flour from pure breeding, isogenic, wheat lines carrying either the high molecular weight glutenin subunits 5 + 10 or 2 + 12. Before dough pasting, subunits 5 + 10 tend to form a stable gluten network relying mainly on disulfide bonds and hydrogen bonds, but 2 + 12 flour was prone to generating fragile protein aggregates dominated by disulfide bonds and hydrophobicity. During dough pasting, a broader protein network rich in un-extractable polymeric proteins, disulfide bonds and ß-sheets was formed in the dough with subunits 5 + 10, thus resulting in an extensive and compact protein-starch complex which was characterized by high thermal stability and low starch gelatinization, while in the dough of the 2 + 12 line, a porous protein-starch gel with fragmented protein aggregates was controlled by the combination of disulfide bonds, hydrophobicity and hydrogen bonds that facilitated the formation of antiparallel ß-sheets.


Assuntos
Farinha , Triticum , Pão , Glutens , Melhoramento Vegetal , Amido
5.
Eur J Med Chem ; 227: 113871, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34638033

RESUMO

The ubiquitination of the hypoxia-inducible factor-1α (HIF-1α) is mediated by interacting with the von Hippel-Lindau protein (VHL), and is associated with cancer, chronic anemia, and ischemia. VHL, an E3 ligase, has been reported to degrade HIF-1 for decades, however, there are few successful inhibitors currently. Poor understanding of the binding pocket and a lack of in-depth exploration of the interactions between two proteins are the main reasons. Hence, we developed an effective strategy to identify and design new inhibitors for protein-protein interaction targets. The hydroxyproline (Hyp564) of HIF-1α contributed the key interaction between HIF-1α and VHL. In this study, detailed information of the binding pocket were explored by alanine scanning, site-directed mutagenesis and molecular dynamics simulations. Interestingly, we found the interaction(s) between Y565 and H110 played a key role in the binding of VHL/HIF-1α. Based on the interactions, 8 derivates of VH032, 16a-h, were synthesized by introducing various groups bounded to H110. Further assay on protein and cellular level exhibited that 16a-h accessed higher binding affinity to VHL and markable or modest improvement in stabilization of HIF-1α or HIF-1α-OH in HeLa cells. Our work provides a new orientation for the modification or design of VHL/HIF-1α protein-protein interaction inhibitors.

6.
J Hazard Mater ; 423(Pt B): 127220, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34844350

RESUMO

The development of antimicrobial resistance (AMR) is accelerated by the selective pressure exerted by the widespread use of antimicrobial drugs, posing an increasing danger to public health. However, long-term spatiotemporal variation in AMR genes in microorganisms, particularly in bacterial pathogens in response to antibiotic consumption, is not fully understood. Here, we used the NCBI RefSeq database to collect 478 whole-genome sequences for Serratia marcescens ranging from 1961 up to 2019, to document global long-term AMR trends in S. marcescens populations. In total, 100 AMR gene subtypes (16 AMR gene types) were detected in the genomes of S. marcescens populations. We identified 3 core resistance genes in S. marcescens genomes, and a high diversity of AMR genes was observed in S. marcescens genomes after corresponding antibiotics were discovered and introduced into clinical practice, suggesting the adaptation of S. marcescens populations to challenges with therapeutic antibiotics. Our findings indicate spatiotemporal variation of AMR genes in S. marcescens populations in relation to antibiotic consumption and suggest the potential transmission of S. marcescens isolates harboring AMR genes among countries and between the environment and the clinic, representing a public health threat that necessitates international solidarity to overcome.

7.
Mol Ther ; 2021 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-34864204

RESUMO

The tumor microenvironment (TME) is a dynamic network of cellular organization that comprises diverse cell types and significantly contributes to cancer development. As pivotal immune stromal cells in the TME, macrophages are extensively heterogeneous and exert both antitumor and protumor functions. Exosomes are nanosized extracellular membranous vesicles with diameters between 30-150 nm. By transferring multiple bioactive substances such as proteins, lipids and nucleic acids, exosomes play an important role in the communication between cells. Recently, growing evidence has demonstrated that non-coding RNAs (ncRNAs) are enriched in exosomes and that exosomal ncRNAs are involved in the crosstalk between cancer cells and macrophages. Furthermore, circulating exosomal ncRNAs can be detected in biofluids, serving as promising noninvasive biomarkers for the early diagnosis and prognostic prediction of cancer. Exosome-based therapies are emerging as potent strategies that can be utilized to alleviate tumor progression. Herein, the present knowledge of exosomal ncRNAs and their vital roles in regulating the interplay between cancer cells and macrophages, as well as their clinical applications are summarized.

8.
JMIR Med Inform ; 9(12): e32698, 2021 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-34889749

RESUMO

BACKGROUND: Electronic medical records (EMRs) are usually stored in relational databases that require SQL queries to retrieve information of interest. Effectively completing such queries can be a challenging task for medical experts due to the barriers in expertise. Existing text-to-SQL generation studies have not been fully embraced in the medical domain. OBJECTIVE: The objective of this study was to propose a neural generation model that can jointly consider the characteristics of medical text and the SQL structure to automatically transform medical texts to SQL queries for EMRs. METHODS: We proposed a medical text-to-SQL model (MedTS), which employed a pretrained Bidirectional Encoder Representations From Transformers model as the encoder and leveraged a grammar-based long short-term memory network as the decoder to predict the intermediate representation that can easily be transformed into the final SQL query. We adopted the syntax tree as the intermediate representation rather than directly regarding the SQL query as an ordinary word sequence, which is more in line with the tree-structure nature of SQL and can also effectively reduce the search space during generation. Experiments were conducted on the MIMICSQL dataset, and 5 competitor methods were compared. RESULTS: Experimental results demonstrated that MedTS achieved the accuracy of 0.784 and 0.899 on the test set in terms of logic form and execution, respectively, which significantly outperformed the existing state-of-the-art methods. Further analyses proved that the performance on each component of the generated SQL was relatively balanced and offered substantial improvements. CONCLUSIONS: The proposed MedTS was effective and robust for improving the performance of medical text-to-SQL generation, indicating strong potential to be applied in the real medical scenario.

9.
Front Genet ; 12: 777931, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34899862

RESUMO

Background: Globally, hepatocellular carcinoma (HCC) is the sixth most frequent malignancy with a high incidence and a poor prognosis. Immune cell infiltration (ICI) underlies both the carcinogenesis and immunogenicity of tumors. However, a comprehensive classification system based on the immune features for HCC remains unknown. Methods: The HCC dataset from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) cohorts was used in this study. The ICI patterns of 571 patients were characterized using two algorithms: the patterns were determined based on the ICI using the ConsensusClusterPlus package, and principal component analysis (PCA) established the ICI scores. Differences in the immune landscape, biological function, and somatic mutations across ICI scores were evaluated and compared, followed by a predictive efficacy evaluation of ICI scores for immunotherapy by the two algorithms and validation using an external immunotherapy cohort. Results: Based on the ICI profile of the HCC patients, three ICI patterns were identified, including three subtypes having different immunological features. Individual ICI scores were determined; the high ICI score subtype was characterized by enhanced activation of immune-related signaling pathways and a significantly high tumor mutation burden (TMB); concomitantly, diminished immunocompetence and enrichment of pathways associated with cell cycle and RNA degradation were found in the low ICI score subtype. Taken together, our results contribute to a better understanding of an active tumor and plausible reasons for its poor prognosis. Conclusion: The present study reveals that ICI scores may serve as valid prognostic biomarkers for immunotherapy in HCC.

10.
Zhonghua Nan Ke Xue ; 27(5): 426-432, 2021 May.
Artigo em Chinês | MEDLINE | ID: mdl-34914318

RESUMO

Objective: To explore the role of transforming growth factor-ß (TGF-ß) in bladder neck contracture (BNC) after transurethral enucleation and resection of the prostate (TUERP). METHODS: This study included 300 BPH patients undergoing TUERP, aged 51-89 (69.19 ± 8.43) years, with the prostate volume of 14.4-355.8 (63.18 ± 47.63) ml and preoperative IPSS of 15-35 (26.07 ± 5.9), QOL score of 3-6 (4.43 ± 0.67), PSA content of 0.17-23.16 (2.94 ± 3.77) ug/L, urinary leukocyte increase in 50 cases, post-void residual urine volume (PVR) of 0-440 (83.53 ± 86.85) ml, and maximum urinary flow rate (Qmax) of 2.3-14.5 (7.77 ± 3.47) ml/s. During TUERP, we collected the tissues from the bladder neck at 5 and 7 o'clock as well as the BPH tissue and the tissue from the residual prostate for HE staining, immunohistochemistry (the SP method) and examination of the infiltration degree of inflammatory cells and expressions of TGF-ß1 and TGF-ß3. During the 6-24 months follow-up, 6 of the patients were confirmed with BNC based on the clinical symptoms and the results of uroflowmetry and cystoscopy, and underwent transurethral bladder neck incision and detection of the expressions of TGF-ß1 and TGF-ß3 in the bladder neck tissue with BNC. RESULTS: The bladder neck tissue without BNC was mainly composed of smooth muscle and fibrous tissues with local infiltration of inflammatory cells, and the residual prostate tissue primarily comprised fibrous and muscle tissues, mixed with a little prostatic epithelial tissue. The bladder neck tissue with BNC, compared with that harvested during the initial TUERP, exhibited significantly increased expression of TGF-ß1 (ï¼»68.20 ± 10.88ï¼½% vs ï¼»36.14 ± 7.62ï¼½%, P < 0.05), decreased expression of TGF-ß3 (ï¼»8.55 ± 4.73ï¼½% vs ï¼»20.77 ± 8.69ï¼½%, P < 0.05), and enhanced infiltration of inflammatory cells (P < 0.05). The bladder neck tissue without BNC, in comparison with the BPH tissue, showed dramatically up-regulated expressions of TGF-ß1 (ï¼»27.05 ± 8.21ï¼½% vs ï¼»1.61 ± 0.69ï¼½%, P < 0.001) and TGF-ß3 (ï¼»14.09 ± 4.19ï¼½% vs ï¼»0.32 ± 0.11ï¼½%, P < 0.001) and increased infiltration of inflammatory cells (P < 0.05). CONCLUSIONS: After TUERP, the expression of TGF-ß1 is increased, that of TGF-ß3 decreased and the infiltration of inflammatory cells enhanced in the bladder neck tissue with BNC, which suggests that BNC may be related to the expression of TGF-ß and that BNC after TUERP could be prevented by regulating the expression of TGF-ß.


Assuntos
Contratura , Bexiga Urinária , Idoso , Idoso de 80 Anos ou mais , Contratura/etiologia , Contratura/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Próstata/cirurgia , Qualidade de Vida , Fator de Crescimento Transformador beta , Bexiga Urinária/cirurgia
11.
BMC Bioinformatics ; 22(Suppl 1): 600, 2021 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-34920699

RESUMO

BACKGROUND: Biomedical named entity recognition (NER) is a fundamental task of biomedical text mining that finds the boundaries of entity mentions in biomedical text and determines their entity type. To accelerate the development of biomedical NER techniques in Spanish, the PharmaCoNER organizers launched a competition to recognize pharmacological substances, compounds, and proteins. Biomedical NER is usually recognized as a sequence labeling task, and almost all state-of-the-art sequence labeling methods ignore the meaning of different entity types. In this paper, we investigate some methods to introduce the meaning of entity types in deep learning methods for biomedical NER and apply them to the PharmaCoNER 2019 challenge. The meaning of each entity type is represented by its definition information. MATERIAL AND METHOD: We investigate how to use entity definition information in the following two methods: (1) SQuad-style machine reading comprehension (MRC) methods that treat entity definition information as query and biomedical text as context and predict answer spans as entities. (2) Span-level one-pass (SOne) methods that predict entity spans of one type by one type and introduce entity type meaning, which is represented by entity definition information. All models are trained and tested on the PharmaCoNER 2019 corpus, and their performance is evaluated by strict micro-average precision, recall, and F1-score. RESULTS: Entity definition information brings improvements to both SQuad-style MRC and SOne methods by about 0.003 in micro-averaged F1-score. The SQuad-style MRC model using entity definition information as query achieves the best performance with a micro-averaged precision of 0.9225, a recall of 0.9050, and an F1-score of 0.9137, respectively. It outperforms the best model of the PharmaCoNER 2019 challenge by 0.0032 in F1-score. Compared with the state-of-the-art model without using manually-crafted features, our model obtains a 1% improvement in F1-score, which is significant. These results indicate that entity definition information is useful for deep learning methods on biomedical NER. CONCLUSION: Our entity definition information enhanced models achieve the state-of-the-art micro-average F1 score of 0.9137, which implies that entity definition information has a positive impact on biomedical NER detection. In the future, we will explore more entity definition information from knowledge graph.


Assuntos
Aprendizado Profundo
12.
Clin Appl Thromb Hemost ; 27: 10760296211067258, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34939445

RESUMO

OBJECTIVE: To explore the correlation between the fracture line inferior plane and perioperative deep venous thrombosis (DVT) in patients with tibial fractures. METHODS: Data was collected from the medical records of 536 consecutive patients with tibial fractures at Xi'an Honghui Hospital. The patients were divided into distal, shaft, and proximal segment groups according to the fracture line inferior plane on radiographs. Multivariate logistic regression models were used to identify the role of the inferior plane of the fracture line in perioperative DVT. RESULTS: A total of 431 patients were included in the study and 226 patients had perioperative DVT in the lower extremities, including 11 proximal and 215 distal DVTs. Univariate regression analysis showed a significant correlation between the proximal segment and perioperative DVT; however, no correlation was found in the shaft segment group. Additionally, age, coronary heart disease, associated injuries, and time to operation ≥6 days were risk factors for perioperative DVT. However, fixation with intramedullary nails may be a protective factor for perioperative DVT compared with plates. After adjusting for potential confounding factors, the proximal segment group had an increased incidence of perioperative DVT compared to the distal segment group. CONCLUSIONS: The proximal segment may be correlated with an increased incidence of perioperative DVT by 7.30-fold in patients with tibial fractures compared to that in the distal segment. In clinical practice, surgeons should be vigilant for DVT formation in these patients.

13.
BMC Med Inform Decis Mak ; 21(Suppl 7): 368, 2021 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-34969377

RESUMO

OBJECTIVE: Relation extraction (RE) is a fundamental task of natural language processing, which always draws plenty of attention from researchers, especially RE at the document-level. We aim to explore an effective novel method for document-level medical relation extraction. METHODS: We propose a novel edge-oriented graph neural network based on document structure and external knowledge for document-level medical RE, called SKEoG. This network has the ability to take full advantage of document structure and external knowledge. RESULTS: We evaluate SKEoG on two public datasets, that is, Chemical-Disease Relation (CDR) dataset and Chemical Reactions dataset (CHR) dataset, by comparing it with other state-of-the-art methods. SKEoG achieves the highest F1-score of 70.7 on the CDR dataset and F1-score of 91.4 on the CHR dataset. CONCLUSION: The proposed SKEoG method achieves new state-of-the-art performance. Both document structure and external knowledge can bring performance improvement in the EoG framework. Selecting proper methods for knowledge node representation is also very important.

14.
Artigo em Inglês | MEDLINE | ID: mdl-34951846

RESUMO

Indirect methods for visual SLAM are gaining popularity due to their robustness to environmental variations. ORB-SLAM2 [1] is a benchmark method in this domain, however, it consumes significant time for computing descriptors that never get reused unless a frame is selected as a keyframe. To overcome these problems, we present FastORB-SLAM which is light-weight and efficient as it tracks keypoints between adjacent frames without computing descriptors. To achieve this, a two stage descriptor-independent keypoint matching method is proposed based on sparse optical flow. In the first stage, we predict initial keypoint correspondences via a simple but effective motion model and then robustly establish the correspondences via pyramid-based sparse optical flow tracking. In the second stage, we leverage the constraints of the motion smoothness and epipolar geometry to refine the correspondences. In particular, our method computes descriptors only for keyframes. We test FastORB-SLAM on TUM and ICL-NUIM RGB-D datasets and compare its accuracy and efficiency to nine existing RGB-D SLAM methods. Qualitative and quantitative results show that our method achieves state-of-the-art accuracy and is about twice as fast as the ORB-SLAM2.

15.
Brain Behav ; : e2416, 2021 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-34775689

RESUMO

PURPOSE: This study investigated the clinical epidemiological characteristics of nitrous oxide (N2 O) abusers in a hospital in China, which have not been systematically reported. METHODS: The characteristics of patients abusing N2 O who were examined and treated at the Affiliated Hospital of Xuzhou Medical University from January 2017 to December 2020 were analyzed. RESULTS: A total of 61 patients (average age: 21.7 ± 3.2 years; 42 male and 19 female) were enrolled; 60.7% of the patients had an education level of high school or lower, and most (59.0%) had no stable occupation. The mean exposure time was 8.5 ± 7.7 months (range: 1-36 months). Only 52.5% of the abusers reported the physician of the relevant exposure history at the first time of visiting the doctor. The main clinical type was mixed (49.2%). The most common clinical manifestation was distal limb numbness (80.3%). The most frequent outcome was peripheral neuropathy (59%) and subacute combined degeneration (36%). Serum homocysteine level was elevated in 67.5% (27/40) of the patients, while 44.4% (20/45) showed reduced vitamin B12. Note that 61% (22/36) showed abnormal signals in the posterior or lateral funiculus of the spinal cord, and 97% (31/32) of the patients showed peripheral nerve damage by electromyography. In all cases, symptoms were alleviated after halting N2 O intake and receiving nutritional neurotherapy. CONCLUSIONS: N2 O abuse can lead to nervous system damage, especially peripheral nerve and spinal cord damage. A full understanding of its clinical epidemiological characteristics is helpful for clinicians to make a timely and clear diagnosis.

16.
Artigo em Inglês | MEDLINE | ID: mdl-34825331

RESUMO

Ratoon rice (RR) is regarded as a labor-saving and efficient approach to rice cultivation; however, sub-optimal production techniques (fertilization, irrigation, harvesting) may lead to serious environmental problems and unsustainable agriculture. In this study, emergy analysis was combined with indicators of soil fertility, global warming potential (GWP), and profitability to comprehensively assess the sustainability performance of three cultivation modes: (i) traditional farm practice (TRA), (ii) optimized mode (OPT), and (iii) OPT plus green manure planting (OPTM). Over 2 years, compared with the TRA mode, OPT and OPTM modes increased total rice yield by 10% and 19% on average and improved profit by 233.7 and 456.5 Yuan ha-1, respectively. Single emergy analysis results showed that, compared with the TRA mode, OPT and OPTM (2-year average value) modes increased production efficiency by 10% and 8%, reduced renewable fraction and emergy sustainability index by 14-19% and 18-23%, respectively, and increased environmental loading ratio by 31% and 22%. Multiple EMA analysis results showed that, compared with the TRA mode, OPT and OPTM (2-year average value) modes reduced UEVNmin by 23% and 21% and increased UEVGWP 32% and 51%, respectively. The UEVTotal revenue and UEVBenefit of OPT and OPTM increased by 8-29% and 4-37%, respectively, compared with TRA mode. The comprehensive assessment indicated that, despite OPT and OPTM modes have a range of improvements and dis-improvements versus the TRA mode, OPTM was the more sustainable mode of RR production overall. However, some sustainability indicators remained poor, and there remains scope for further optimization via, e.g., precision application of enhanced-efficiency fertilizers, application of a straw-decomposing inoculant to improve soil fertility, and use of new improved rice varieties with high regenerative ability to improve the yield of ratoon crops.

17.
Animals (Basel) ; 11(11)2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34827922

RESUMO

Extracellular vesicles (EVs), which exist in the follicular fluid of ruminant ovaries, are considered as cargo carriers for the transfer of biomolecules to recipient cells. However, the functions and changes in EVs in antral follicles remain ambiguous. In the present study, we isolated and characterized EVs from goat follicular fluid by means of differential ultracentrifugation and Western blotting of marker proteins. Bioinformatics tools were used to detect miRNA expression levels in EVs. Different miRNA expression patterns of EVs exist in small to large follicles. Thirteen differentially expressed miRNAs (seven upregulated and six downregulated) were identified and used for analysis. A total of 1948 predicted target genes of 13 miRNAs were mapped to signaling pathways, and three significantly enriched pathways (FoxO, MAPK, and PI3K-AKT signaling pathways) were involved in follicular development, as revealed by KEGG enrichment analysis. Our findings suggest that EVs in follicular fluid play biofunctional roles during follicular development in goats.

18.
Appl Intell (Dordr) ; : 1-18, 2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34764609

RESUMO

As the global pandemic of the COVID-19 continues, the statistical modeling and analysis of the spreading process of COVID-19 have attracted widespread attention. Various propagation simulation models have been proposed to predict the spread of the epidemic and the effectiveness of related control measures. These models play an indispensable role in understanding the complex dynamic situation of the epidemic. Most existing work studies the spread of epidemic at two levels including population and agent. However, there is no comprehensive statistical analysis of community lockdown measures and corresponding control effects. This paper performs a statistical analysis of the effectiveness of community lockdown based on the Agent-Level Pandemic Simulation (ALPS) model. We propose a statistical model to analyze multiple variables affecting the COVID-19 pandemic, which include the timings of implementing and lifting lockdown, the crowd mobility, and other factors. Specifically, a motion model followed by ALPS and related basic assumptions is discussed first. Then the model has been evaluated using the real data of COVID-19. The simulation study and comparison with real data have validated the effectiveness of our model.

19.
Nanotechnology ; 33(6)2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34678796

RESUMO

We report on the fabrication and characterization of high-resolution gratings with high efficiency in the extreme ultraviolet (EUV) and soft x-ray ranges using spin-on-carbon (SOC) underlayers. We demonstrate the fabrication of diffraction gratings down to 20 nm half-pitch (HP) on Si3N4membranes with a bilayer of hydrogen silsesquioxane (HSQ) and spin-on-carbon and show their performance as a grating mask for extreme ultraviolet interference lithography (EUV-IL). High-resolution patterning of HSQ is possible only for thin films due to pattern collapse. The combination of this high-resolution resist with SOC circumvents this problem and enables the fabrication of high aspect ratio nanostructures. Rigorous coupled-wave analysis shows that the bilayer gratings exhibit higher diffraction efficiency than what is feasible with a grating made of HSQ. We also demonstrate a simple and accurate method to experimentally measure the diffraction efficiency of high-resolution gratings by measuring the relative ratio of the dose-to-clear curves of the photoresist. The measured diffraction efficiencies are in good agreement with the theoretically predicted values. Furthermore, we verify our calculations and measurements by printing line/space patterns in chemically amplified resists down to 10 nm HP with both HSQ and bilayer grating masks using EUV-IL. The improved diffraction efficiency of the bilayers is expected to have applications not only in gratings for interference lithography, but also in Fresnel zone plates and gratings for spectroscopy in the EUV and soft x-ray ranges.

20.
Ecol Evol ; 11(18): 12294-12306, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34594500

RESUMO

Understanding genetic variation and structure, adaptive genetic variation, and its relationship with environmental factors is of great significance to understand how plants adapt to climate change and design effective conservation and management strategies. The objective of this study was to (I) investigate the genetic diversity and structure by AFLP markers in 36 populations of R. aureum from northeast China, (Ⅱ) reveal the relative contribution of geographical and environmental impacts on the distribution and genetic differentiation of R. aureum, (Ⅲ) identify outlier loci under selection and evaluate the association between outlier loci and environmental factors, and (Ⅳ) exactly calculate the development trend of population of R. aureum, as it is confronted with severe climate change and to provide information for designing effective conservation and management strategies. We found high genetic variation (I = 0.584) and differentiation among populations (ΦST  = 0.703) and moderate levels of genetic diversity within populations of R. aureum. A significant relationship between genetic distance and environmental distance was identified, which suggested that the differentiation of different populations was caused by environmental factors. Using BayeScan and Dfdist, 42 outlier loci are identified and most of the outlier loci are associated with climate or relief factors, suggesting that these loci are linked to genes that are involved in the adaptability of R. aureum to the environment. Species distribution models (SDMs) showed that climate warming will cause a significant reduction in suitable areas for R. aureum, especially under the RCP 85 scenario. Our results help to understand the potential response of R. aureum to climatic changes and provide new perspectives for R. aureum resource management and conservation strategies.

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