49 research outputs found
A modelâdata study of the 1999 St. Lawrence Island polynya in the Bering Sea
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95536/1/jgrc12221.pd
Hawking radiation-quasinormal modes correspondence for large AdS black holes
It is well-known that the non-strictly thermal character of the Hawking
radiation spectrum generates a natural correspondence between Hawking radiation
and black hole quasinormal modes. This main issue has been analyzed in the
framework of Schwarzschild black holes, Kerr black holes and nonextremal
Reissner-Nordstrom black holes. In this paper, by introducing the effective
temperature, we reanalysis the non-strictly thermal character of large AdS
black holes. The results show that the effective mass corresponding to the
effective temperature is approximatively the average one in any dimension. And
the other effective quantities can also be obtained. Based on the known forms
of frequency in quasinormal modes, we reanalysis the asymptotic frequencies of
the large AdS black hole in three and five dimensions. Then we get the formulas
of the Bekenstein-Hawking entropy and the horizon's area quantization with
functions of the quantum "overtone" number .Comment: 6 page
Decreased NPC1L1 expression in the liver from Chinese female gallstone patients
<p>Abstract</p> <p>Background</p> <p>Cholesterol gallstone disease is a very common disease in both industrialized and developing countries. Many studies have found that cholesterol gallstones are more common in women than men. The molecular mechanisms underlying the relationship between female gallstone disease and hepatic sterol transporters are still undergoing definition and have not been evaluated in humans.</p> <p>Aims</p> <p>The aim of this study is to probe for underlying hepatic molecular defects associated with development of gallstones in female.</p> <p>Methods/Results</p> <p>Fifty-seven nonobese, normolipidemic Chinese female gallstone patients (GS) were investigated with 12 age- and body mass index-matched female gallstone-free controls (GSF). The bile from the female GS had higher cholesterol saturation than that from the female GSF. The hepatic NPC1L1 mRNA levels were lower in female GS, correlated with SREBP2 mRNA. NPC1L1 downregulation was confirmed at protein levels. Consistently, immunohistochemistry showed decreased NPC1L1 expression in female GS.</p> <p>Conclusions</p> <p>The decreased hepatic NPC1L1 levels in female GS might indicate a downregulated reabsorption of biliary cholesterol in the liver, which, in turn, leads to the cholesterol supersaturation of bile. Our data are consistent with the possibility that hepatic NPC1L1 may be mediated by SREBP2.</p
Overcoming Insulin Insufficiency by Forced Follistatin Expression in β -cells of db/db Mice
Diabetes poses a substantial burden to society as it can lead to serious complications and premature death. The number of cases continues to increase worldwide. Two major causes of diabetes are insulin resistance and insulin insufficiency. Currently, there are few antidiabetic drugs available that can preserve or protect β-cell function to overcome insulin insufficiency in diabetes. We describe a therapeutic strategy to preserve β-cell function by overexpression of follistatin (FST) using an AAV vector (AAV8-Ins-FST) in diabetic mouse model. Overexpression of FST in the pancreas of db/db mouse increased β-cell islet mass, decreased fasting glucose level, alleviated diabetic symptoms, and essentially doubled lifespan of the treated mice. The observed islet enlargement was attributed to β-cell proliferation as a result of bioneutralization of myostatin and activin by FST. Overall, our study indicates overexpression of FST in the diabetic pancreas preserves β-cell function by promoting β-cell proliferation, opening up a new therapeutic avenue for the treatment of diabetes
Exposures to particulate matters and childhood sleep disordersâA large study in three provinces in China
Objectives: Evidence on the link between long-term ambient particulate matter (PM) exposures and childhood sleep disorders were scarce. We examined the associations between long-term exposures to PM2.5 and PM1 (PM with an aerodynamic equivalent diameter <2.5 Îźm and <1 Îźm, respectively) with sleep disorders in children. Methods: We performed a population-based cross-sectional survey in 177,263 children aged 6 to 18 years in 14 Chinese cities during 2012â2018. A satellite-based spatiotemporal model was employed to estimate four-year annual average PM2.5 and PM1 exposures at residential and school addresses. Parents or guardians completed a checklist using the Sleep Disturbance Scale for Children. We estimated the associations using generalized linear mixed models with adjustment for characteristics of children, parents, and indoor environments. Results: Long-term PM2.5 and PM1 exposures were positively associated with odds of sleep disorders for almost all domains. For example, increments in PM2.5 and PM1 per 10 Îźg/m3 were associated with odds ratios of global sleep disorder of 1.24 (95 % confidence interval [CI]: 1.14, 1.35) and 1.31 (95 %CI: 1.18, 1.46), respectively. Similar results were observed for subtypes of sleep disorder. These associations were heterogeneous regionally, with stronger associations among children residing in southeast region than in northeast and northwest regions. Moreover, larger estimates of PM1 were found than that of PM2.5 in southeast region. Conclusion: Long-term PM2.5 and PM1 exposures are independently associated with higher risks of childhood sleep disorders, and these associations vary by geographical region
High-Throughput Sequencing-Based Analysis of Rhizosphere and Diazotrophic Bacterial Diversity Among Wild Progenitor and Closely Related Species of Sugarcane (Saccharum spp. Inter-Specific Hybrids)
Considering the significant role of genetic background in plant-microbe interactions and
that most crop rhizospheric microbial research was focused on cultivars, understanding
the diversity of root-associated microbiomes in wild progenitors and closely related
crossable species may help to breed better cultivars. This study is aimed to fill a critical
knowledge gap on rhizosphere and diazotroph bacterial diversity in the wild progenitors
of sugarcane, the essential sugar and the second largest bioenergy crop globally. Using a
high-throughput sequencing (HTS) platform, we studied the rhizosphere and diazotroph
bacterial community of SaccharumofficinarumL. cv. Badila (BRS), Saccharumbarberi (S.
barberi) Jesw. cv Pansahi (PRS), Saccharum robustum [S. robustum; (RRS), Saccharum
spontaneum (S. spontaneum); SRS], and Saccharum sinense (S. sinense) Roxb. cv Uba
(URS) by sequencing their 16S rRNA and nifH genes. HTS results revealed that a total
of 6,202 bacteria-specific operational taxonomic units (OTUs) were identified, that were
distributed as 107 bacterial groups. Out of that, 31 rhizobacterial families are commonly
spread in all five species. With respect to nifH gene, S. barberi and S. spontaneum
recorded the highest and lowest number of OTUs, respectively. These results were
validated by quantitative PCR analysis of both genes. A total of 1,099 OTUs were identified for diazotrophs with a core microbiome of 9 families distributed among all the
sugarcane species. The core microbiomes were spread across 20 genera. The increased
microbial diversity in the rhizosphere was mainly due to soil physiochemical properties.
Most of the genera of rhizobacteria and diazotrophs showed a positive correlation,
and few genera negatively correlated with the soil properties. The results showed
that sizeable rhizospheric diversity exists across progenitors and close relatives. Still,
incidentally, the rhizosphere microbial abundance of progenitors of modern sugarcane
was at the lower end of the spectrum, indicating the prospect of Saccharum species
introgression breeding may further improve nutrient use and disease and stress tolerance
of commercial sugarcane. The considerable variation for rhizosphere microbiome seen
in Saccharum species also provides a knowledge base and an experimental system for
studying the evolution of rhizobacteria-host plant association during crop domestication