Existing studies reveal that the shape corners of hexagonal fiber affect the degree of constraint on the matrix material. However, none of these studies included the effect of orientation of ...hexagonal fibers. In this study, a computational micromechanics model of oriented hexagonal fibers in periodic unidirectional composite materials is established for the determination of effective orthotropic elastic properties of the composite. In the present numerical modeling, the representative unit composite cell including the matrix material and the single oriented hexagonal fiber or random oriented hexagonal fibers is solved by micro-scale finite element analysis with different stress loads and periodic displacement boundary conditions, which are applied along the cell boundary to meet the requirement of straight-line constraint during deformation of the cell. Subsequently, the effective elastic properties of the composite are evaluated for periodic regular packing and random packing using the homogenization approach for investigating the influence of unified orientation and random orientation of the hexagonal fibers on the overall elastic properties of the fiber-reinforced composites. The numerical results are verified by comparing with other available results.
We investigated the effect of systematic smartphone usage on the motor and somatosensory finger functions in healthy subjects. Seventeen right-handed healthy volunteers participated in the study. A ...somewhat better finger sensorimotor function was observed in smartphone non-users. Within the group of smartphone systematic users, the amount of smartphone usage negatively correlated with the spatial discrimination threshold in the fingers. These findings suggest that the input method of the device may not be the only factor influencing the sensorimotor function (other structural differences of the input may also contribute), and that frequent use of the fingers might enhance spatial discrimination. The respective studies can help us to understand interaction between the sensorimotor function and tools and give some insight on how newly developed tools may affect the human brain.
Abstract
In current manufacture process of pebble fuel elements for HTGR, the green pebbles were first carbonized, then lathed and purified at high temperature. The whole heat treatment process ...included two cycles of heating and cooling and corresponding two loading and unloading processes, which took approximately 90 hours in total. In order to reduce the time and energy consumed and improve the efficiency during the heat treatment process, a consecutive heat treatment process of pebble fuel elements for HTGR was established. In the newly established consecutive heat treatment process, the pebble fuel elements were carbonized and high temperature purified continuously in a specific furnace. The consecutive heat treatment process took less than 60 hours, which included only one cycle of heating and cooling and corresponding one loading and unloading process. Moreover, in order to recycle the matrix graphite powder after lathing, the green pebbles were machined to a certain size before suffering the heat treatment. However, in order to make the size of pebble fuel elements after the consecutive heat treatment meet the technical requirements, it is necessary to figure out their dimension changes during the heat treatment. As the pebbles were prepared by cold quasi-isostatic molding method, their dimension changes parallel and perpendicular to the molding direction were different. In order to better control the dimension changes of pebbles in the heat treatment process, the effects of physical properties such as apparent density, and particle size distribution of matrix graphite powder on the prepared pebbles were comparatively studied. Finally, the consecutive heat treatment of pre-lathed pebble fuel elements for HTGR was established. The comprehensive properties of pebbles prepared with the newly established consecutive heat treatment process satisfied all the technical requirements.
Purpose
Papillary thyroid carcinoma (PTC) represents the most common subtype of thyroid cancer (TC). This study was set out to explore the potential effect of CHD1L on PTC and type 2 diabetes ...mellitus (T2DM).
Methods
We searched for T2DM susceptibility genes through the GWAS database and obtained T2DM-related differentially expressed gene from the GEO database. The expression and clinical data of TC and normal samples were collated from the TCGA database. Receiver operating characteristic (ROC) curve analysis was subsequently applied to assess the sensitivity and specificity of the CHD1L for the diagnosis of PTC. The MCP-counter package in R language was then utilized to generate immune cell score to evaluate the relationship between CHD1L expression and immune cells. Then, we performed functional enrichment analysis of co-expressed genes and DEGs to determine significantly enriched GO terms and KEGG to predict the potential functions of CHD1L in PTC samples and T2DM adipose tissue.
Results
From two genes (ABCB9, CHD1L) were identified to be DEGs (
p
< 1 * 10
−5
) that exerted effects on survival (HR > 1,
p
< 0.05) in PTC and served as T2DM susceptibility genes. The gene expression matrix-based scoring of immunocytes suggested that PTC samples with high and low CHD1L expression presented with significant differences in the tumor microenvironment (TME). The enrichment analysis of CHD1L co-expressed genes and DEGs suggested that CHD1L was involved in multiple pathways to regulate the development of PTC. Among them, Kaposi sarcoma-associated herpesvirus infection, salmonella infection and TNF signaling pathways were highlighted as the three most relevant pathways. GSEA analysis, employed to analyze the genome dataset of PTC samples and T2DM adipose tissue presenting with high and low expression groups of CHD1L, suggests that these differential genes are related to chemokine signaling pathway, leukocyte transendothelial migration and TCELL receptor signaling pathway.
Conclusion
CHD1L may potentially serve as an early diagnostic biomarker for PTC, and a target of immunotherapy for PTC and T2DM.
Islanding detection is a mandatory function for grid-connected converters. The popular slip mode frequency shift (SMS) and auto phase shift active islanding detection methods are investigated and an ...improved (IM)-SMS strategy is proposed in this study. In the proposed method, additional phase shift is introduced to help in stimulating the action of the islanding detection and the algorithm is simplified as well. When the utility grid is disconnected, the algorithm keeps the frequency of the converter output voltage deviating until the frequency protection relay is triggered. The working principle of the method is introduced and the guidance of parameters selection and optimisation is also provided. The islanding detection performance is evaluated through theoretical analysis and verified by digital simulation and experimental results. The IM-SMS method exhibits features of simplicity, easy implementation and high reliability.
The design criteria for a nine-story office building, subject to earthquakes and winds, are developed based on the method in the companion paper. The seismic and wind hazards, structural response ...analyses, and cost estimates are based on recent literature. Structural limit states in the nonlinear range and consequences are considered. The optimal design is obtained by minimizing the total expected life-cycle cost using a numerical procedure. A sensitivity analysis is conducted comparing the optimal design to the important but controversial parameters, such as design life, death and injury cost, structural capacity uncertainty, and discount rate. The method is applied to design under earthquakes, winds, and both hazards at Los Angeles, Seattle, and Charleston, South Carolina, and compared with current design. As expected, the seismic load controls the optimal design in Los Angeles. The optimal design is "dominated" by seismic load in Seattle and wind load in Charleston. These hazards, however, do not "control" or "govern" the design, for the lesser hazard still contributes significantly. Also, contrary to common belief, uniform reliability against different hazards is not required.
Celotno besedilo
Dostopno za:
DOBA, FGGLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The multi-scale deformation and interfacial mechanical behavior of carbon nanotube fibers with multi-level structures are investigated by experimental and theoretical methods. Multi-scale experiments ...including uniaxial tensile testing,
in situ
Raman spectroscopy, and scanning electron microscopy are conducted to measure the mechanical response of multi-level structures within the fiber under tension. A two-level interfacial mechanical model is then presented to analyze the interfacial bonding strength of mesoscopic bundles and microscopic nanotubes. The evolution characteristics of multi-scale deformation of the fiber are described based on experimental characterization and interfacial strength analysis. The strengthening mechanism of the fiber is further studied. Comprehensive analysis shows that the property of multi-level interfaces is a critical factor for the fiber strength and toughness. Finally, the method of improving the mechanical properties of fiber-based materials is discussed. The result can be used to guide multi-level interface engineering of carbon nanotube fibers and fiber-based composites to produce high performance materials.
In this paper, a method for analyzing the high-frequency attenuation property of polyurea-matrix composites is developed by combining experimental, computational and theoretical approaches. First, ...the ultrasonic experimental platform is established by solving the difficulties of high-frequency ultrasonic testing as high-frequency signal distortion, insufficient driving voltage and sampling rate failure, to study the dynamic mechanical properties (1–5 MHz) of pure polyurea and polyurea-matrix composites. Then, the influences of composite parameters including the size and volume fraction of inclusions on wave attenuation performance under different frequencies are obtained and further verified by numerical simulations. Next, the contribution of inclusions to the wave attenuation performance is also theoretically analyzed. It is found that the increase of inclusion volume fraction and inclusion diameter will increase the attenuation coefficient of the composites. And the attenuation of composites with the inclusions of a 150-μm diameter and 30% as volume fraction can be 82% higher than pure matrix. This amplifying attenuation effect of inclusions is mainly attributed to the scattering effect, which is verified by comparing numerical and theoretical results.
Graphical abstract
To analyze the clinical characteristics and risk factors of malignant vasovagal syncope (VVS) in children.
This was a case-control study. The data of 368 VVS patients who were treated in the ...Department of Cardiology, Children's Hospital, Capital Institute of Pediatrics from June 2017 to December 2021 was collected and analyzed. They were divided into malignant VVS group and non-malignant VVS group according to the presence of sinus arrest, and then their demographic characteristics were compared. The children with malignant VVS and complete clinical information were recruited into the case group and were matched by age and sex (1∶4 ratio) with non-malignant VVS patients during the same period.Their clinical characteristics and lab tests were compared. Independent sample
test, Mann Whitney
or χ
test was used for comparison between groups.Logistic regression was used to analyze the risk factors for malignant VVS in children.
Eleven malignant VVS and 342 non-malignant VVS met the inclusion and exclusion critera.
Although recent studies have demonstrated associations between nonchromosomal birth defects and several pediatric cancers, less is known about their role on childhood leukemia susceptibility. Using ...data from the Childhood Cancer and Leukemia International Consortium, we evaluated associations between nonchromosomal birth defects and childhood leukemia. Pooling consortium data from 18 questionnaire‐based and three registry‐based case‐control studies across 13 countries, we used multivariable logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between a spectrum of birth defects and leukemia. Our analyses included acute lymphoblastic leukemia (ALL, n = 13 115) and acute myeloid leukemia (AML, n = 2120) cases, along with 46 172 controls. We used the false discovery rate to account for multiple comparisons. In the questionnaire‐based studies, the prevalence of birth defects was 5% among cases vs 4% in controls, whereas, in the registry‐based studies, the prevalence was 11% among cases vs 7% in controls. In pooled adjusted analyses, there were several notable associations, including (1) digestive system defects and ALL (OR = 2.70, 95% CI: 1.46‐4.98); (2) congenital anomalies of the heart and circulatory system and AML (OR = 2.86, 95% CI: 1.81‐4.52) and (3) nervous system defects and AML (OR = 4.23, 95% CI: 1.50‐11.89). Effect sizes were generally larger in registry‐based studies. Overall, our results could point to novel genetic and environmental factors associated with birth defects that could also increase leukemia susceptibility. Additionally, differences between questionnaire‐ and registry‐based studies point to the importance of complementary sources of birth defect phenotype data when exploring these associations.
What's new?
Little is known about whether nonchromosomal birth defects serve etiological roles in childhood leukemia. Birth defects potentially associated with childhood leukemia include congenital disorders affecting the heart and circulatory system, nervous system, or digestive system. Here, the authors sought to identify associations between childhood leukemia and nonchromosomal birth defects using data from the Childhood Cancer and Leukemia International Consortium. Certain defects, including those of the circulatory, nervous and digestive systems, were strongly associated with increased risk of leukemia. The newly described associations open the way to better understanding links between nonchromosomal birth defects, genetic and environmental factors and increased leukemia susceptibility.
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