25 research outputs found
Almost sure convergence for the maxima of strongly dependent stationary Gaussian vector sequences
AbstractIn this paper, we prove the almost sure limit theorem of the maxima for a kind of strongly dependent stationary Gaussian vector sequences
Tbx20 Is Required in Mid-Gestation Cardiomyocytes and Plays a Central Role in Atrial Development.
RationaleMutations in the transcription factor TBX20 (T-box 20) are associated with congenital heart disease. Germline ablation of Tbx20 results in abnormal heart development and embryonic lethality by embryonic day 9.5. Because Tbx20 is expressed in multiple cell lineages required for myocardial development, including pharyngeal endoderm, cardiogenic mesoderm, endocardium, and myocardium, the cell type-specific requirement for TBX20 in early myocardial development remains to be explored.ObjectiveHere, we investigated roles of TBX20 in midgestation cardiomyocytes for heart development.Methods and resultsAblation of Tbx20 from developing cardiomyocytes using a doxycycline inducible cTnTCre transgene led to embryonic lethality. The circumference of developing ventricular and atrial chambers, and in particular that of prospective left atrium, was significantly reduced in Tbx20 conditional knockout mutants. Cell cycle analysis demonstrated reduced proliferation of Tbx20 mutant cardiomyocytes and their arrest at the G1-S phase transition. Genome-wide transcriptome analysis of mutant cardiomyocytes revealed differential expression of multiple genes critical for cell cycle regulation. Moreover, atrial and ventricular gene programs seemed to be aberrantly regulated. Putative direct TBX20 targets were identified using TBX20 ChIP-Seq (chromatin immunoprecipitation with high throughput sequencing) from embryonic heart and included key cell cycle genes and atrial and ventricular specific genes. Notably, TBX20 bound a conserved enhancer for a gene key to atrial development and identity, COUP-TFII/Nr2f2 (chicken ovalbumin upstream promoter transcription factor 2/nuclear receptor subfamily 2, group F, member 2). This enhancer interacted with the NR2F2 promoter in human cardiomyocytes and conferred atrial specific gene expression in a transgenic mouse in a TBX20-dependent manner.ConclusionsMyocardial TBX20 directly regulates a subset of genes required for fetal cardiomyocyte proliferation, including those required for the G1-S transition. TBX20 also directly downregulates progenitor-specific genes and, in addition to regulating genes that specify chamber versus nonchamber myocardium, directly activates genes required for establishment or maintenance of atrial and ventricular identity. TBX20 plays a previously unappreciated key role in atrial development through direct regulation of an evolutionarily conserved COUPT-FII enhancer
Parallel Lineage-Tracing Studies Establish Fibroblasts as the Prevailing In Vivo Adipocyte Progenitor.
Summary: Despite decades of studies suggesting that the in vivo adipocyte progenitor resides within the vascular niche, the exact nature of this progenitor remains controversial because distinct studies have attributed adipogenic properties to multiple vascular cell types. Using Cre recombinases labeling distinct vascular lineages, we conduct parallel lineage tracing experiments to assess their degree of contribution to de novo adipogenesis. Although we detect occasional adipocytes that were lineage traced by endothelial or mural recombinases, these are rare events. On the other hand, platelet-derived growth factor receptor alpha (PDGFRα)-expressing adventitial or capsular fibroblasts make a significant contribution to adipocytes in all depots and experimental settings tested. Our data also suggest that fibroblasts transition to an intermediate beige adipocyte phenotype prior to differentiating to a mature white adipocyte. These observations, together with histological analyses revealing that adipose tissue fibroblasts express the mural cell marker PDGFRβ, harmonize a highly controversial field with implications for multiple human diseases, including the pandemic of obesity. : Cattaneo et al. used genetic fate mapping in murine models to test the adipogenic potential of distinct cell types of the vascular wall. These parallel lineage-tracing experiments reveal that fibroblasts are the sole vascular cell type with significant adipocyte progenitor activity, giving rise to brown, beige, and white adipocytes. Keywords: adipogenesis, obesity, vascular wall, lineage tracing, endothelium, mural cells, fibroblast
Asymptotic distributions of maxima of complete and incomplete samples from multivariate stationary Gaussian sequences
Let be a sequence of d-dimensional stationary Gaussian vectors, and let denote the partial maxima of . Suppose that there are missing data in each component of and let denote the partial maxima of the observed variables. In this note, we study two kinds of asymptotic distributions of the random vector where the correlation and cross-correlation satisfy some dependence conditions.Asymptotic distribution Missing data Multivariate stationary Gaussian vector Weak and strong dependence
Synthesis of tungsten disulfide (WS2) nanoflakes for lithium ion battery application
A novel method (a rheological phase reaction) was used to synthesize WS2 nanoflakes by adding oxalic acid as a reducing reagent. High resolution electron microscopy observations revealed that the as-prepared WS2 nanoflakes had started to curve and that WS2 nanotubes were partly formed. The lithium intercalation/deintercalation behavior of as-prepared WS2 electrode was also investigated. It was found that the WS2 nanoflake electrode exhibited higher specific capacity with very good cycling stability compared to WS2 nanotube or nanoparticle electrodes. The reasons for the improved electrochemical performance of the nanoflake electrodes are also discussed
Synthesis and electrochemical properties of LiY0.1V3O8
LiY0.1V3O8 compound was successfully prepared by using a simple, rapid and easily scaled up method, i.e. the rheological phase reaction method. The microstructural characteristics of LiY0.1V3O8 materials were examined by X-ray diffraction and scanning electron microscopy (SEM). Compared with LiV3O8 compound, the LiY0.1V3O8 shows expanded crystal lattices, and the expansion is more significant along the c-axis. The electrochemical properties of the as-synthesized LiY0.1V3O8 compounds were investigated. It was found that the LiY0.1V3O8 electrodes exhibited better reversibility and higher capacities than LiV3O8 electrodes. The reasons for the improved electrochemical performance of the LiY0.1V3O8 electrodes are also discussed
The Application of Pediatric Ureteroscope for Seminal Vesiculoscopy
To describe a novel technique of transurethral seminal vesiculoscopy using a pediatric ureteroscope in the diagnosis and management of persistent hematospermia, a retrospective study was carried out for 20 patients with recurrent hematospermia whom we evaluated and treated using a 6–7.5F (6F front end and 7.5F rear end) pediatric ureteroscope from August 2009 to September 2013. For the 20 patients, the age ranges from 25 to 48 years with a mean age of 36 years. The duration of the hematospermia ranges from 6 to 48 months with a mean duration of 18 months. Transurethral seminal vesiculoscopy was successfully performed in the 20 cases and the mean operative time was 35 min (ranges from 25 to 90 min). Among the 20 patients, 11 patients were found to have seminal vesiculitis, five were with seminal vesicle stone, one was with prostatic utricle stone, one was with prostate cyst, and one was with ejaculatory duct obstruction. The mean follow-up period was 7 months (ranged from 6 to 12 months). Hematospermia in 19 cases disappeared after the surgery and only in one patient the hematospermia recurred 6 months after the surgery. The cure rate was 95%. This study indicated that transurethral seminal vesiculoscopy could be performed easily using a semirigid pediatric ureteroscope with few complications and is an effective therapeutic approach for persistent hematospermia
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Filamin C is Essential for mammalian myocardial integrity
FLNC, encoding filamin C, is one of the most mutated genes in dilated and hypertrophic cardiomyopathy. However, the precise role of filamin C in mammalian heart remains unclear. In this study, we demonstrated Flnc global (FlncgKO) and cardiomyocyte-specific knockout (FlnccKO) mice died in utero from severely ruptured ventricular myocardium, indicating filamin C is required to maintain the structural integrity of myocardium in the mammalian heart. Contrary to the common belief that filamin C acts as an integrin inactivator, we observed attenuated activation of β1 integrin specifically in the myocardium of FlncgKO mice. Although deleting β1 integrin from cardiomyocytes did not recapitulate the heart rupture phenotype in Flnc knockout mice, deleting both β1 integrin and filamin C from cardiomyocytes resulted in much more severe heart ruptures than deleting filamin C alone. Our results demonstrated that filamin C works in concert with β1 integrin to maintain the structural integrity of myocardium during mammalian heart development