Ghrelin attenuates avascular necrosis of the femoral head induced by steroids in rabbits

Purpose: Ghrelin is an endogenous ligand for growth hormone secretagogue receptor. The current study was aimed at examining the effect of ghrelin on avascular necrosis of the femoral head (ANFH) induced by steroids in a rabbit model and also exploring the underlying mechanism. Methods: Experimental rabbits were separated into three groups: Control, Vehicle and Ghrelin. We established a steroid-induced ANFH model in rabbits. Then, MRI scanning and hematoxylin-eosin staining (HE) were conducted to see ANFH. The mRNA levels of Vascular Endothelial Growth Factor (VEGF) and Bone Morphogenetic Protein 2 (BMP-2) were evaluated using real-time qRT-PCR. Results: Rabbits in the Vehicle group showed increased empty bone lacunae, reduced bone trabecula in femoral head; the number of hematopoietic cells in the bone marrow was reduced, whereas number of adipocytes increased with evident fusion phenomenon in comparison with the Control group. All of the changes induced in Vehicle group were attenuated in Ghrelin group. MRI scanning showed obvious necrosis of femoral head in the Vehicle group and less in the Ghrelin group. The mRNA levels of VEGF and BMP-2 were raised in Vehicle group and further enhanced in Ghrelin group. Conclusion: Ghrelin attenuates steroid-induced avascular necrosis in femoral head in rabbit model. A possible mechanism may be through VEGF/BMP-2 axis. Keywords: ANFH, BMP-2, Ghrelin, VEG

Snow accumulation variability over the West Antarctic Ice Sheet since 1900: a comparison of ice core records with ERA-20C reanalysis

This study uses a set of 37 firn core records over the West Antarctic Ice Sheet (WAIS) to test the performance of ERA-20C reanalysis for snow accumulation and quantify temporal variability in snow accumulation since 1900. The firn cores are allocated to four geographical areas demarcated by drainage divides (i.e., Antarctic Peninsula (AP), western WAIS, central WAIS and eastern WAIS) to calculate stacked records of regional snow accumulation. Our results show that the inter-annual variability in ERA-20C precipitation minus evaporation (P-E) agrees well with the corresponding ice core snow accumulation composites in each of the four geographical regions, suggesting its skill for simulating snow accumulation changes before the modern satellite era (pre-1979). Snow accumulation experiences significantly positive trends for the AP and eastern WAIS, a negative trend for the western WAIS, and no significant trend for the central WAIS from 1900 to 2010. The contrasting trends are associated with changes in the large-scale moisture transport driven by a deepening of the low-pressure systems and anomalies of sea ice in the Amundsen Sea Low (ASL) region

Identification of renal cyst cells of type I Nephronophthisis by single-nucleus RNA sequencing

Background: Nephronophthisis (NPH) is the most common genetic cause of end-stage renal disease (ESRD) in childhood, and NPHP1 is the major pathogenic gene. Cyst formation at the corticomedullary junction is a pathological feature of NPH, but the mechanism underlying cystogenesis is not well understood. The isolation and identification of cystic cell subpopulation could help to identify their origins and provide vital clues to the mechanisms underlying cystogenesis in NPH.Methods: Single-nucleus RNA sequencing (snRNA-seq) was performed to produce an atlas of NPHP1 renal cells. Kidney samples were collected from WT (Nphp1+/+) mice and NPHP1 (Nphp1del2-20/del2-20) model mice.Results: A comprehensive atlas of the renal cellular landscape in NPHP1 was generated, consisting of 14 basic renal cell types as well as a subpopulation of DCT cells that was overrepresented in NPHP1 kidneys compared to WT kidneys. GO analysis revealed significant downregulation of genes associated with tubular development and kidney morphogenesis in this subpopulation. Furthermore, the reconstruction of differentiation trajectories of individual cells within this subpopulation confirmed that a specific group of cells in NPHP1 mice become arrested at an early stage of differentiation and proliferate to form cysts. We demonstrate that Niban1 is a specific molecular marker of cystic cells in both mice and human NPHP1.Conclusion: In summary, we report a novel subpopulation of DCT cells, marked by Niban1, that are classified as cystic cells in the NPHP1 mice kidney. These results offer fresh insights into the cellular and molecular basis of cystogenesis in NPH

Room temperature 2D ferromagnetism in few-layered 1TT-CrTe2_{2}

Spin-related electronics using two dimensional (2D) van der Waals (vdW) materials as a platform are believed to hold great promise for revolutionizing the next generation spintronics. Although many emerging new phenomena have been unravelled in 2D electronic systems with spin long-range orderings, the scarcely reported room temperature magnetic vdW material has thus far hindered the related applications. Here, we show that intrinsic ferromagnetically aligned spin polarization can hold up to 316 K in a metallic phase of 1$T$-CrTe$_{2}$ in the few-layer limit. This room temperature 2D long range spin interaction may be beneficial from an itinerant enhancement. Spin transport measurements indicate an in-plane room temperature negative anisotropic magnetoresistance (AMR) in few-layered CrTe$_{2}$, but a sign change in the AMR at lower temperature, with -0.6$\%$ at 300 K and +5$\%$ at 10 K, respectively. This behavior may originate from the specific spin polarized band structure of CrTe$_{2}$. Our findings provide insights into magnetism in few-layered CrTe$_{2}$, suggesting potential for future room temperature spintronic applications of such 2D vdW magnets.Comment: 9 Pages, 4 Figure

Degradation and corresponding failure mechanism for GaN-based LEDs

The degradation behaviors of high power GaN-based vertical blue LEDs on Si substrates were measured using in-situ accelerated life test. The results show that the dominant failure mechanism would be different during the operation. Besides that, the corresponding associated failure mechanisms were investigated systematically by using different analysis technologies, such as Scan Electron Microscopy, Reflectivity spectroscopy, Transient Thermal Analysis, Raman Spectra, etc. It is shown that initially, the failure modes were mainly originated from the semiconductor die and interconnect, while afterwards, the following serious deterioration of the radiant fluxes was attributed to the package. The interface material and quality, such as die attach and frame, play an important role in determining the thermal performance and reliability. In addition, the heating effect during the operation will also release the compressive strain in the chip. These findings will help to improve the reliability of GaN-based LEDs, especially for the LEDs with vertical structure

Genome-Wide Identification and Characterization of Hsf and Hsp Gene Families and Gene Expression Analysis under Heat Stress in Eggplant (Solanum melongema L.)

Under high temperature stress, a large number of proteins in plant cells will be denatured and inactivated. Meanwhile Hsfs and Hsps will be quickly induced to remove denatured proteins, so as to avoid programmed cell death, thus enhancing the thermotolerance of plants. Here, a comprehensive identification and analysis of the Hsf and Hsp gene families in eggplant under heat stress was performed. A total of 24 Hsf-like genes and 117 Hsp-like genes were identified from the eggplant genome using the interolog from Arabidopsis. The gene structure and motif composition of Hsf and Hsp genes were relatively conserved in each subfamily in eggplant. RNA-seq data and qRT-PCR analysis showed that the expressions of most eggplant Hsf and Hsp genes were increased upon exposure to heat stress, especially in thermotolerant line. The comprehensive analysis indicated that different sets of SmHsps genes were involved downstream of particular SmHsfs genes. These results provided a basis for revealing the roles of SmHsps and SmHsp for thermotolerance in eggplant, which may potentially be useful for understanding the thermotolerance mechanism involving SmHsps and SmHsp in eggplant

Genome-Wide Identification and Expression Analysis in Oxidative Stress of TCP Transcription Factor Family in Eggplant (Solanum melongena L.)

【Objective】The study was carried out to identify the SmTCP gene and analyze the members of SmTCP transcription factor family in eggplant. The determination of its expression under stress and hormone treatment laid a foundation for further study of the function of SmTCP gene in eggplant.【Method】The members of SmTCP gene family were identified from the eggplant genome. The physicochemical properties and distribution of members of SmTCP transcription factor family in eggplant were analyzed by bioinformatics methods. Eggplant seedlings were treated with high temperature (42 ℃), low temperature (4℃), salt stress (200 μmol/L NaCl solution), heavy metal (100 μmol/L CdCl2 solution), Pseudomonas solanacearum, salicylic acid and abscisic acid. The expression of SmTCP gene in eggplant under seven treatments was analyzed by qRT-PCR.【Result】A total of 32 SmTCP members were identified and analyzed by bioinformatics method. The results of qRT-PCR analysis showed that the SmTCP gene of eggplant was up-regulated in response to biological and environmental stress. Under hormone treatment, the SmTCP of eggplant was up-regulated generally after ABA treatment, and the SmTCP of eggplant was down-regulated generally after SA treatment. The contents of SmTCP in leaves and fruits were higher.【Conclusion】It was found that the SmTCP gene of eggplant express in response to stress. The expression of different SmTCP members in response to stress and the expression levels in various organs are different. Most of the Class I TCP members of eggplant are significantly up-regulated under heat stress. Therefore, it is speculated that the SmTCP gene of eggplant may be involved in resisting adversity stress

Composite degradation model and corresponding failure mechanism for mid-power GaN-based white LEDs

The degradation mechanism of mid-power GaN-based white LEDs were investigated by using the in-situ multi-functional accelerated aging tests. The changes of the luminous flux and the chromaticity shift during the stress time show some correlations. To quantitatively analyze the degradation behavior, a composite model considering the luminous flux increasing and decreasing mechanisms was proposed and the results agree well with the experiments in the entire aging time. Furthermore, different analytical technologies have been used to understand the cause of luminous flux degradation and chromaticity shift. The results show that the chromaticity shift was mainly due to the phosphors deterioration, while the serious degradation of luminous flux was the overall effects from the package, including the phosphors deterioration and oxidation of silicone encapsulant