4,337 research outputs found
Beyond relativistic mean-field studies of low-lying states in neutron-deficient krypton isotopes
Neutron-deficient krypton isotopes are of particular interest due to the
coexistence of oblate and prolate shapes in low-lying states and the transition
of ground-state from one dominate shape to another as a function of neutron
number. A detailed interpretation of these phenomena in neutron-deficient Kr
isotopes requires the use of a method going beyond a mean-field approach that
permits to determine spectra and transition probabilities. The aim of this work
is to provide a systematic calculation of low-lying state in the even-even
68-86Kr isotopes and to understand the shape coexistence phenomenon and the
onset of large collectivity around N=40 from beyond relativistic mean-field
studies. The starting point of our method is a set of relativistic
mean-field+BCS wave functions generated with a constraint on triaxial
deformations (beta, gamma). The excitation energies and electric multipole
transition strengths of low-lying states are calculated by solving a
five-dimensional collective Hamiltonian (5DCH) with parameters determined by
the mean-field wave functions. To examine the role of triaxiality, a
configuration mixing of both particle number (PN) and angular momentum (AM)
projected axially deformed states is also carried out within the exact
generator coordinate method (GCM) based on the same energy density functional.
The energy surfaces, the excitation energies of 0^+_2, 2^+_1, 2^+_2 states, as
well as the E0 and E2 transition strengths are compared with the results of
similar 5DCH calculations but with parameters determined by the
non-relativistic mean-field wave functions, as well as with the available
data...Comment: 23 pages, 10 figure
Suppression of hepatitis B virus replication by SRPK1 and SRPK2 via a pathway independent of the phosphorylation of the viral core protein
AbstractThe SR-domain protein kinase (SRPK) 1 and 2 are two important kinases involved in cellular RNA splicing. Recently, it was suggested that these two kinases, which could bind to the hepatitis B virus (HBV) core protein, might be the major cellular kinases that phosphorylate the core protein to regulate HBV replication. In this report, we tested the role of SRPK1 and SRPK2 in HBV replication and found that both of them could suppress HBV replication by reducing the packaging efficiency of the pgRNA without affecting the formation of the viral core particles. This suppressive effect of SRPK1 and SRPK2 on HBV replication cannot be explained by their phosphorylation activities on the HBV core protein as the over-expression of these two kinases had no detectable effects on HBV core protein phosphorylation in vivo and their mutants that lacked the kinase activity could still suppress HBV DNA replication. Thus, these findings demonstrate a negative role of SRPK1 and SRPK2 in the regulation of HBV replication through a mechanism not involving the phosphorylation of the core protein
Sleep duration and patterns in Chinese older adults: A comprehensive meta-analysis
This meta-analysis examined the mean sleep duration and patterns in Chinese older adult population. A literature search was systematically conducted covering major English (PubMed, Embase and PsycINFO) and Chinese (Chinese National Knowledge Infrastructure (CNKI), WanFang and SinoMed) databases. Data in studies with the mean and standard deviation of sleep duration and/or the proportion of short and long sleep durations in Chinese older adults were extracted and pooled using random-effects models. Subgroup analyses were conducted according to gender, region, area, survey time and sample size. A total of 36 studies with 150,616 subjects were included for analyses. The pooled mean sleep duration of 21 studies with available data was 6.82 hours/day (95% CI: 6.59â7.05 hours/day). The estimated proportions of sleep duration \u3c5 hours/day, \u3c6 hours/day, \u3c7 hours/day were 18.8% (95% CI: 1.7%â35.9%), 26.7% (95% CI: 19.7%â33.7%) and 42.3% (95% CI: 34.8%â49.8%), respectively. The pooled proportions for long sleepers were 22.6% (95% CI: 13.9%â31.4%) (\u3e8 hours/day) and 17.6% (95% CI: 12.4%â22.9%) (\u3e9 hours/day). Given the adverse effects of unhealthy sleep patterns, health professionals should pay more attention to sleep patterns in this population in China
The prevalence of autism spectrum disorders in China: A comprehensive meta-analysis
There are conflicting prevalence estimates of autism spectrum disorders (ASDs) in mainland China (China thereafter). This study is a comprehensive meta-analysis of the pooled prevalence of ASDs in the general population in China. Study investigators independently conducted a systematic literature search of the following databases: PubMed, EMBASE, PsycINFO, China National Knowledge Infrastructure, Chinese biomedical literature service system, and Wan Fang. Studies reporting prevalence of ASDs and autism in Chinese population were identified and analysed using the Comprehensive Meta-Analysis program with the random effects model. Forty-four studies were included in the meta-analysis comprising 2,337,321 subjects of whom 46.66 % were females. The mean age of subjects ranged from 1.6 to 8 years. Based on diagnostic criteria the pooled prevalence of ASDs was 39.23 per 10,000 (95% CI: 28.44-50.03 per 10,000, I2=89.2%); specifically, the prevalence of autism was 10.18 per 10,000 (95% CI: 8.46-11.89 per 10,000, I2=92.5%). Subgroup analyses revealed significant difference in the prevalence of ASDs between genders (72.77 per 10,000 in males vs. 16.45 per 10,000 in females). In conclusion, the prevalence of ASDs and autism in China was found generally lower than those reported in other countries. Further studies are needed to clarify the variation in prevalence
Genetically Encoded Biosensors Reveal PKA Hyperphosphorylation on the Myofilaments in Rabbit Heart Failure
RATIONALE:
In heart failure, myofilament proteins display abnormal phosphorylation, which contributes to contractile dysfunction. The mechanisms underlying the dysregulation of protein phosphorylation on myofilaments is not clear.
OBJECTIVE:
This study aims to understand the mechanisms underlying altered phosphorylation of myofilament proteins in heart failure.
METHODS AND RESULTS:
We generate a novel genetically encoded protein kinase A (PKA) biosensor anchored onto the myofilaments in rabbit cardiac myocytes to examine PKA activity at the myofilaments in responses to adrenergic stimulation. We show that PKA activity is shifted from the sarcolemma to the myofilaments in hypertrophic failing rabbit myocytes. In particular, the increased PKA activity on the myofilaments is because of an enhanced ÎČ2 adrenergic receptor signal selectively directed to the myofilaments together with a reduced phosphodiesterase activity associated with the myofibrils. Mechanistically, the enhanced PKA activity on the myofilaments is associated with downregulation of caveolin-3 in the hypertrophic failing rabbit myocytes. Reintroduction of caveolin-3 in the failing myocytes is able to normalize the distribution of ÎČ2 adrenergic receptor signal by preventing PKA signal access to the myofilaments and to restore contractile response to adrenergic stimulation.
CONCLUSIONS:
In hypertrophic rabbit myocytes, selectively enhanced ÎČ2 adrenergic receptor signaling toward the myofilaments contributes to elevated PKA activity and PKA phosphorylation of myofilament proteins. Reintroduction of caveolin-3 is able to confine ÎČ2 adrenergic receptor signaling and restore myocyte contractility in response to ÎČ adrenergic stimulation
Analysis and Verification of Service Interaction Protocols - A Brief Survey
Modeling and analysis of interactions among services is a crucial issue in
Service-Oriented Computing. Composing Web services is a complicated task which
requires techniques and tools to verify that the new system will behave
correctly. In this paper, we first overview some formal models proposed in the
literature to describe services. Second, we give a brief survey of verification
techniques that can be used to analyse services and their interaction. Last, we
focus on the realizability and conformance of choreographies.Comment: In Proceedings TAV-WEB 2010, arXiv:1009.330
Rethinking Semantic Segmentation from a Sequence-to-Sequence Perspective with Transformers
Most recent semantic segmentation methods adopt a fully-convolutional network
(FCN) with an encoder-decoder architecture. The encoder progressively reduces
the spatial resolution and learns more abstract/semantic visual concepts with
larger receptive fields. Since context modeling is critical for segmentation,
the latest efforts have been focused on increasing the receptive field, through
either dilated/atrous convolutions or inserting attention modules. However, the
encoder-decoder based FCN architecture remains unchanged. In this paper, we aim
to provide an alternative perspective by treating semantic segmentation as a
sequence-to-sequence prediction task. Specifically, we deploy a pure
transformer (ie, without convolution and resolution reduction) to encode an
image as a sequence of patches. With the global context modeled in every layer
of the transformer, this encoder can be combined with a simple decoder to
provide a powerful segmentation model, termed SEgmentation TRansformer (SETR).
Extensive experiments show that SETR achieves new state of the art on ADE20K
(50.28% mIoU), Pascal Context (55.83% mIoU) and competitive results on
Cityscapes. Particularly, we achieve the first position in the highly
competitive ADE20K test server leaderboard on the day of submission.Comment: CVPR 2021. Project page at https://fudan-zvg.github.io/SETR
Biophysical Phenotyping and Modulation of ALDH+ Inflammatory Breast Cancer StemâLike Cells
Cancer stemâlike cells (CSCs) have been shown to initiate tumorigenesis and cancer metastasis in many cancer types. Although identification of CSCs through specific marker expression helps define the CSC compartment, it does not directly provide information on how or why this cancer cell subpopulation is more metastatic or tumorigenic. In this study, the functional and biophysical characteristics of aggressive and lethal inflammatory breast cancer (IBC) CSCs at the singleâcell level are comprehensively profiled using multiple microengineered tools. Distinct functional (cell migration, growth, adhesion, invasion and selfârenewal) and biophysical (cell deformability, adhesion strength and contractility) properties of ALDH+ SUM149 IBC CSCs are found as compared to their ALDHâ nonâCSC counterpart, providing biophysical insights into why CSCs has an enhanced propensity to metastasize. It is further shown that the cellular biophysical phenotype can predict and determine IBC cellsâ tumorigenic ability. SUM149 and SUM159 IBC cells selected and modulated through biophysical attributesâadhesion and stiffnessâshow characteristics of CSCs in vitro and enhance tumorigenicity in in vivo murine models of primary tumor growth. Overall, the multiparametric cellular biophysical phenotyping and modulation of IBC CSCs yields a new understanding of IBCâs metastatic properties and how they might develop and be targeted for therapeutic interventions.This study comprehensively profiles the biophysical characteristics of inflammatory breast cancer stemâlike cells to delineate the soâcalled âbiophysical phenotypeâ of the model of the most metastatic breast cancer subtype. Evidence indicates that the cellular biophysical phenotype can predict and determine cancer cellsâ tumorigenic ability.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147780/1/smll201802891_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147780/2/smll201802891.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147780/3/smll201802891-sup-0001-S1.pd
A Combined Theoretical and Photoelectron Spectroscopy Study of Al3Hn- (n=1-9) clusters
Combined photoelectron spectroscopic experiments and computational studies have been performed on Al3Hn- (n=1-9) clusters. Three modes of hydrogen bonding to the Al-3 moiety have been observed: terminal, bridging, and capping. Among various hydrides, Al3H5- and Al3H8- clusters have highest HOMO-LUMO gap and largest electron affinity, respectively. Our studies indicate that as the number of hydrogen atoms increase the presence of AlH2 groups, representing the tetrahedral coordination of the Al atom, which in turn led to the stoichiometric ring structure
Sequential establishment of stripe patterns in an expanding cell population
Periodic stripe patterns are ubiquitous in living organisms, yet the underlying developmental processes are complex and difficult to disentangle. We describe a synthetic genetic circuit that couples cell density and motility. This system enabled programmed Escherichia coli cells to form periodic stripes of high and low cell densities sequentially and autonomously. Theoretical and experimental analyses reveal that the spatial structure arises from a recurrent aggregation process at the front of the continuously expanding cell population. The number of stripes formed could be tuned by modulating the basal expression of a single gene. The results establish motility control as a simple route to establishing recurrent structures without requiring an extrinsic pacemaker.published_or_final_versio
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