To achieve polymer-based composites for electronic packaging with low dielectric constant, low dielectric loss tangent and high thermal conductivity, silane coupling agent KH550 modified hexagonal ...boron nitride (hBN) platelets were introduced into PTFE matrix via a cold pressing and sintering method. The effect of surface treatment on the morphology, thermal conductivity and dielectric properties of the composites was investigated. The results revealed that after surface treatment, the interfacial adhension between hBN platelets and PTFE matrix was improved and the in-plane orientation degree of hBN platelets in PTFE matrix decreased, which effectively improvd the thermal conductivity of the composites. The thermal conductivity of hBN-KH550/PTFE composite with 30 vol% filler content is 0.722 W/mK, which is 2.7 folds of pure PTFE. Moreover, the enhanced interfacial adhension and reduced surface hydrophilicity of hBN platelets significantly decreased the interfacial polarization, resulting in not only lower dielectric constant and dielectric loss tangent but also weaker frequency-dependence.
Traumatic brain injury (TBI) and spinal cord injury (SCI) are two main central nervous system (CNS) traumas, caused by external physical insults. Both injuries have devastating effects on the quality ...of life, and there is no effective therapy at present. Notably, gene expression profiling using bulk RNA sequencing (RNA-Seq) and single-cell RNA-Seq (scRNA-Seq) have revealed significant changes in many coding and non-coding genes, as well as important pathways in SCI and TBI. Particularly, recent studies have revealed that long non-coding RNAs (lncRNAs) with lengths greater than 200 nucleotides and without protein-coding potential have tissue- and cell type-specific expression pattern and play critical roles in CNS injury by gain- and loss-of-function approaches. LncRNAs have been shown to regulate protein-coding genes or microRNAs (miRNAs) directly or indirectly, participating in processes including inflammation, glial activation, cell apoptosis, and vasculature events. Therefore, lncRNAs could serve as potential targets for the diagnosis, treatment, and prognosis of SCI and TBI. In this review, we highlight the recent progress in transcriptome studies of SCI and TBI and insights into molecular mechanisms.
•The role of hydroxyl groups in the electron transfer from Fe(II) to CT was studied.•The rate of reductive dechlorination of CT by FHC increased with increasing OH− dosage.•Increase of OH− dosage ...leads to a more symmetric octahedral structure of Fe(II) in FHC.•Increase of Fe(OH)2 crystallinity leads to an increased reductive activity of FHC.
Reductive dechlorination of chlorinated organic pollutants (COPs) by Fe(II) occurs in natural environments and engineered systems. Fe(II) ions undergo hydroxylation in aqueous solutions to form Ferrous Hydroxyl Complex (FHC), which plays an essential role in Fe(II)-mediated reductive dechlorination. However, how hydroxyl groups of FHC bridge the electron transfer from Fe(II) to COPs is still not fully understood. This work shows that the rate of reductive dechlorination of carbon tetrachloride (CT) by FHC increased with increasing OH− dosage. XRD data shows the increase of OH− dosage transform FHC from Fe2(OH)3Cl to Fe(OH)2, which leads to increased reductive strength of FHC. More non-hydrogen bonded hydroxyl groups coordinate with Fe(II) in FHC with increasing the OH− dosage, which stabilizes the octahedral structure of Fe(II) as shown by Mössbauer data. Electrochemical analysis reveals that the increase of OH− dosage enhances the reductive activity of FHC, which is also confirmed by the decreased HOMO-LUMO gap. It was found that FHC dechlorinated CT to methane, which was attributed to the stabilization of trichlorocarbene anion(˸CCl3−) by surface-O-Fe(II)-OH+. This work deepens our understanding on the bridge effect of hydroxyl groups on the electron transfer from Fe(II) to COPs, and provides a theoretical foundation for the reductive dechlorination of COPs in both natural environments and engineered systems.
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The major cell classes of the brain differ in their developmental processes, metabolism, signaling, and function. To better understand the functions and interactions of the cell types that comprise ...these classes, we acutely purified representative populations of neurons, astrocytes, oligodendrocyte precursor cells, newly formed oligodendrocytes, myelinating oligodendrocytes, microglia, endothelial cells, and pericytes from mouse cerebral cortex. We generated a transcriptome database for these eight cell types by RNA sequencing and used a sensitive algorithm to detect alternative splicing events in each cell type. Bioinformatic analyses identified thousands of new cell type-enriched genes and splicing isoforms that will provide novel markers for cell identification, tools for genetic manipulation, and insights into the biology of the brain. For example, our data provide clues as to how neurons and astrocytes differ in their ability to dynamically regulate glycolytic flux and lactate generation attributable to unique splicing of PKM2, the gene encoding the glycolytic enzyme pyruvate kinase. This dataset will provide a powerful new resource for understanding the development and function of the brain. To ensure the widespread distribution of these datasets, we have created a user-friendly website (http://web.stanford.edu/group/barres_lab/brain_rnaseq.html) that provides a platform for analyzing and comparing transciption and alternative splicing profiles for various cell classes in the brain.
Aim
To synthesize qualitative evidence on nurses' and midwives' experiences in the provision of surgical abortion care. We address three specific questions: (a) what are the experiences of nurses and ...midwives in surgical abortion care? (b) what are their responses and coping strategies? (c) what are the deficiencies in surgical abortion care?
Design
Qualitative studies were synthesized using Thomas and Harden's qualitative thematic synthesis method.
Data sources
Electronic databases, including PubMed, Embase, CINAHL, PsycINFO, Scopus and Web of Science were searched. Grey literature using ProQuest was searched. The databases were searched from inception to 5 August 2020.
Review methods
The SPIDER (Sample, Phenomenon of Interest, Design, Evaluation and Research type) search tool was used in the literature search. Data synthesis was conducted using the three‐stage thematic synthesis method described by Thomas and Harden.
Results
966 studies were identified in the initial search and 18 studies were included. Four analytical themes were generated: ‘Providing abortion care requires high emotional labour’; ‘Professionalism of abortion care providers’; ‘Initiatives in professional development’ and ‘Improving directions for high‐quality abortion care’.
Conclusion
Nurses and midwives indicated that they require support to enhance psychological health and improve professional skills. Hospital managers should organize regular debriefing or structured group workshops for exchange of practical experiences and strengthening emotional support. More research is required to establish comprehensive training related to abortion care for nurses and midwives. The findings demonstrate that optimization of abortion services should start from hospital management models, pain management and bereavement care.
Impact
Understanding the experiences of nurses and midwives in abortion provision will inform future clinical practice in surgical abortion care, which would be helpful in improving the professionalism and confidence of abortion providers. Our findings have implications for the training, development of policies and standards for surgical abortion care for nurses and midwives.
Previous studies showed an inverse association between ideal cardiovascular health (CVH) metrics and the total risk of cardiovascular diseases and stroke. This study aimed to investigate the ...relationship between ideal CVH metrics and the risks of ischemic and hemorrhagic stroke, respectively.
We collected information on the 7 ideal CVH metrics (including smoking status, body mass index, dietary intake, physical activity, blood pressure, total cholesterol, and fasting blood glucose) among 91 698 participants from the Kailuan study, China (72 826 men and 18 872 women between the ages of 18 and 98 years), free of myocardial infarction and stroke at baseline (2006-2007). Cox proportional hazards models were used to estimate stroke risk.
During the 4-year follow-up, we identified 1486 incident stroke events (1057 ischemic, 386 intracerebral hemorrhagic, and 43 subarachnoid hemorrhagic). The hazard ratios (95% confidence interval) for total stroke with adherence to 0 (reference), 1, 2, 3, 4, 5, and 6/7 ideal CVH metrics were: 1, 0.92 (0.69-1.23), 0.69 (0.52-0.92), 0.52 (0.39-0.68), 0.38 (0.28-0.51), 0.27 (0.18-0.40), and 0.24 (0.11-0.54), respectively (P trend <0.01), after adjusting for age, sex, education, income, and hospital. Similar inverse associations were observed for both ischemic and intracerebral hemorrhagic stroke (both P trend <0.01).
We observed a clear inverse gradient relationship between the number of ideal CVH metrics and the risk of stroke in a Chinese population, supporting the importance of ideal health behaviors and factors in stroke prevention.
Citrinin (CTN) is a mycotoxin, which is isolated from Penicillium citrinum and widely existed in the contaminated feeds. It is reported that CTN is toxic to heart, liver, and reproductive system. ...Previous studies indicated that CTN induced apoptosis in oocytes and embryos. In this study, we reported the potential causes of CTN on embryo development. Our results showed that 40 μM CTN exposure significantly reduced the first cleavage of mouse embryos, showing with the low rate of 2‐cell embryos. We found that CTN induced DNA damage, showing the higher positive γH2A.X signals. Autophagy was occurred since more LC3 positive autophagosomes were found in the cytoplasm. This could be confirmed by the enhanced lysosome function, since higher accumulated lysosome distribution were found and LAMP2 was also increased under CTN exposure. Besides, we showed that mitochondria distribution was disturbed, indicating that CTN could disrupt mitochondria function, which could be the possible reason for the oxidative stress and apoptosis in CTN‐exposed embryos. In conclusion, our study showed that CTN exposure had adverse effects on the early embryo development during first cleavage through its effects on the induction of DNA damage, autophagy, and mitochondria dysfunction.
Alzheimer's disease (AD) is a progressive neurodegenerative disease and is the most common cause of dementia in an aging population. The majority of research effort has focused on the role of neurons ...in neurodegeneration and current therapies have limited ability to slow disease progression. Recently more attention has been given to the role of astrocytes in the process of neurodegeneration. Specifically, reactive astrocytes have both advantageous and adverse effects during neurodegeneration. The ability to isolate and depict astrocyte phenotype has been challenging. However, with the recent development of single-cell sequencing technologies researchers are provided with the resource to delineate specific biomarkers associated with reactive astrocytes in AD. In this review, we will focus on the role of astrocytes in normal conditions and the pathological development of AD. We will further review recent developments in the understanding of astrocyte heterogeneity and associated biomarkers. A better understanding of astrocyte contributions and phenotypic changes in AD can ultimately lead to more effective therapeutic targets.
Background:
Early-stage diagnosis and treatment can improve survival rates of liver cancer patients. Dynamic contrast-enhanced MRI provides the most comprehensive information for differential ...diagnosis of liver tumors. However, MRI diagnosis is affected by subjective experience, so deep learning may supply a new diagnostic strategy. We used convolutional neural networks (CNNs) to develop a deep learning system (DLS) to classify liver tumors based on enhanced MR images, unenhanced MR images, and clinical data including text and laboratory test results.
Methods:
Using data from 1,210 patients with liver tumors (
N
= 31,608 images), we trained CNNs to get seven-way classifiers, binary classifiers, and three-way malignancy-classifiers (Model A-Model G). Models were validated in an external independent extended cohort of 201 patients (
N
= 6,816 images). The area under receiver operating characteristic (ROC) curve (AUC) were compared across different models. We also compared the sensitivity and specificity of models with the performance of three experienced radiologists.
Results:
Deep learning achieves a performance on par with three experienced radiologists on classifying liver tumors in seven categories. Using only unenhanced images, CNN performs well in distinguishing malignant from benign liver tumors (AUC, 0.946; 95% CI 0.914–0.979 vs. 0.951; 0.919–0.982,
P
= 0.664). New CNN combining unenhanced images with clinical data greatly improved the performance of classifying malignancies as hepatocellular carcinoma (AUC, 0.985; 95% CI 0.960–1.000), metastatic tumors (0.998; 0.989–1.000), and other primary malignancies (0.963; 0.896–1.000), and the agreement with pathology was 91.9%.These models mined diagnostic information in unenhanced images and clinical data by deep-neural-network, which were different to previous methods that utilized enhanced images. The sensitivity and specificity of almost every category in these models reached the same high level compared to three experienced radiologists.
Conclusion:
Trained with data in various acquisition conditions, DLS that integrated these models could be used as an accurate and time-saving assisted-diagnostic strategy for liver tumors in clinical settings, even in the absence of contrast agents. DLS therefore has the potential to avoid contrast-related side effects and reduce economic costs associated with current standard MRI inspection practices for liver tumor patients.