134 research outputs found
One dimensional terpyridine-based metal organic framework for stable supercapacitor
In summary, a novel structure of MOF based on 1,4âdi ([2,2':6',2''terpyridin] -4'-yl)benzene and 1,4-naphthalenedicarboxylic acid has been constructed through hydrothermal reaction. The Ni-MOF displays one dimensional zigzag chain, which connect each other by hydrogen bonding to form three dimensional supramolecule with large channels. The conjugated systems of the terpyridin and benzene ligands enhance the chain rigidity, accelerate the electron transport. The massive channels provides electrolyte rapid transfer. By the structural feature aforementioned, the Ni-MOF demonstrates stable electrochemical performance as suprocapacitor
On the origin of the split main sequences of the young massive cluster NGC 1856
The detection of split main sequences (MSs) associated with young clusters
(600 Myr) has caught lots of attention. A prevailing scenario is that
a bimodality of stellar rotation distribution drives the MS bifurcation.
Nevertheless, the origin of the stellar rotation dichotomy remains unclear.
Hypotheses involving tidally-locked binaries or blue straggler stars (BSSs) are
proposed to explain the observed split MSs. This work examines if the long-term
dynamical evolution of star clusters can produce the observed split MSs,
through high-performance -body simulation. As a prototype example, the young
massive cluster NGC 1856 exhibits an apparent MS bifurcation. Our simulation
reports that at the age of NGC 1856, tidally-locked binaries are fully mixed
with single stars. This is consistent with the observation that there is no
significant spatial difference between blue MS and red MS stars. However, we
find that only high mass-ratio binaries can evolve to the tidally-locked phase
at the age of the NGC 1856. These tidally-locked binaries will populate a much
redder sequence than the MS of single stars rather than a blue MS, which is
inconsistent with the hypothesis. The number of tidally-locked binaries cannot
account for the observation. Our simulation shows that BSSs produced by binary
interactions do populate the blue periphery in the color-magnitude diagram, and
their spatial distribution shows a similar pattern of single stars. However,
the number of BSSs does not fit the observation.Comment: 14 pages, 7 figures, 1 table; accepted for publication in Ap
VCL Challenges 2023 at ICCV 2023 Technical Report: Bi-level Adaptation Method for Test-time Adaptive Object Detection
This report outlines our team's participation in VCL Challenges B Continual
Test_time Adaptation, focusing on the technical details of our approach. Our
primary focus is Testtime Adaptation using bi_level adaptations, encompassing
image_level and detector_level adaptations. At the image level, we employ
adjustable parameterbased image filters, while at the detector level, we
leverage adjustable parameterbased mean teacher modules. Ultimately, through
the utilization of these bi_level adaptations, we have achieved a remarkable
38.3% mAP on the target domain of the test set within VCL Challenges B. It is
worth noting that the minimal drop in mAP, is mearly 4.2%, and the overall
performance is 32.5% mAP
Different effects of acute and chronic oxidative stress on the intestinal flora and gut-liver axis in weaned piglets
IntroductionOxidative stress plays a pivotal role in modulating the balance of intestinal flora and the gut-liver axis, while also serving as a key determinant of the growth potential of weaned piglets. However, few studies have subdivided and compared acute and chronic oxidative stress.MethodsIn this study, an intestinal model of acute oxidative stress in weaned piglets using paraquat (PQ) and a chronic oxidative stress model using D-galactosa in weaned piglets were conducted. And we further systematically compare their effects.ResultsBoth acute and chronic oxidative stress models impaired intestinal barrier function and liver function. Chronic stress caused by D-galactose can result in severe redox dysregulation, while acute stress caused by paraquat can lead to inflammation and liver damage. Additionally, the components involved in the CAR pathway were expressed differently. Chronic or acute oxidative stress can reduce the diversity and composition of intestinal flora. In the PQ group, the richness of Mogibacterium and Denitratisoma improved, but in the D-gal group, the richness of Catenisphaera and Syntrophococcus increased.DiscussionNot only does this research deepen our understanding of the effects of acute and chronic oxidative stress on intestinal functions, but it also characterizes characteristic changes in the gut flora, potentially identifying novel therapeutic targets and opening new avenues for future research
Synthetic θâDefensin Antibacterial Peptide as a Highly Efficient Nonviral Vector for RedoxâResponsive miRNA Delivery
Synthetic cationic vectors have shown great promise for nonviral gene delivery. However, their cytotoxicity and low efficiency impose great restrictions on clinic applications. To push through this limitation, humanized peptides or proteins with cationic biocompatibility as well as biodegradation would be an excellent candidate. Herein, for the first time, we describe how an arginineârich humanized antimicrobial cyclopeptide, θâdefensin, can be used as a synthetic cationic vector to load and deliver miRNA into bone mesenchymal stem cells with high efficiency and ultralow cytotoxicity, surpassing the efficiency of the commercial polyethylenimine (25 kD) and Lipofectamine 3000. To note, θâdefensin can redoxâresponsively release the loaded miRNA through a structural change: in extracellular oxidative environment, θâdefensin has large βâsheet structures stabilized by three disulfide linkages, and this special structure enables highly efficient delivery of miRNA by passing through cell membranes; in intracellular environment, redoxâresponsive disulfide linkages are broken and the tight βâsheet structures are destroyed, so that the miRNA can be released. Our results suggest that synthetic θâdefensin peptides are a new class of nonviral gene vectors and this study may also provide a promising strategy to design smartâresponsive gene vectors with high efficiency and minimal toxicity.This study describes how an arginineârich humanized antimicrobial cyclopeptide, θâdefensin, can be used as a synthetic cationic vector to load and deliver miRNA into bone mesenchymal stem cells with high efficiency and low cytotoxicity, surpassing the efficiency of the commercial polyethylenimine (25 kD) and Lipofectamine 3000.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141894/1/adbi201700001.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141894/2/adbi201700001_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/141894/3/adbi201700001-sup-0001-S1.pd
Acylhydrazine-based reticular hydrogen bonds enable robust, tough, and dynamic supramolecular materials
Supramolecular materials are widely recognized among the most promising candidates for future generations of sustainable plastics because of their dynamic functions. However, the weak noncovalent cross-links that endow dynamic properties usually trade off materialsâ mechanical robustness. Here, we present the discovery of a simple and robust supramolecular cross-linking strategy based on acylhydrazine units, which can hierarchically cross-link the solvent-free network of poly(disulfides) by forming unique reticular hydrogen bonds, enabling the conversion of soft into stiff dynamic material. The resulting supramolecular materials exhibit increase in stiffness exceeding two to three orders of magnitude compared to those based on the hydrogen-bonding network of analogous carboxylic acids, simultaneously preserving the repairability, malleability, and recyclability of the materials. The materials also show high adhesion strength on various surfaces while allowing multiple surface attachment cycles without fatigue, illustrating a viable approach how robustness and dynamics can be merged in future material design
The role of tidal interactions in the formation of slowly rotating early-type stars in young star clusters
The split main sequences found in the colour-magnitude diagrams of star
clusters younger than ~600 Myr are suggested to be caused by the dichotomy of
stellar rotation rates of upper main-sequence stars. Tidal interactions have
been suggested as a possible explanation of the dichotomy of the stellar
rotation rates. This hypothesis proposes that the slow rotation rates of stars
along the split main sequences are caused by tidal interactions in binaries. To
test this scenario, we measured the variations in the radial velocities of
slowly rotating stars along the split main sequence of the young Galactic
cluster NGC 2422 (~90 Myr) using spectra obtained at multiple epochs with the
Canada-France-Hawai'i Telescope. Our results show that most slowly rotating
stars are not radial-velocity variables. Using the theory of dynamical tides,
we find that the binary separations necessary to fully or partially synchronise
our spectroscopic targets, on time-scales shorter than the cluster age, predict
much larger radial velocity variations across multiple-epoch observations, or a
much larger radial velocity dispersion at a single epoch, than the observed
values. This indicates that tidal interactions are not the dominant mechanism
to form slowly rotating stars along the split main sequences. As the
observations of the rotation velocity distribution among B- and A-type stars in
binaries of larger separations hint at a much stronger effect of braking with
age, we discuss the consequences of relaxing the constraints of the dynamical
tides theory.Comment: 14 pages, 10 figures, 2 tables, accepted for publication in MNRA
Molecular basis of ligand recognition and activation of human V2 vasopressin receptor.
Vasopressin type 2 receptor (V2R) belongs to the vasopressin (VP)/oxytocin (OT) receptor subfamily of G protein-coupled receptors (GPCRs), which comprises at least four closely related receptor subtypes: V1aR, V1bR, V2R, and OTR. These receptors are activated by arginine vasopressin (AVP) and OT, two endogenous nine-amino acid neurohypophysial hormones, which are thought to mediate a biologically conserved role in social behavior and sexual reproduction. V2R is mainly expressed in the renal collecting duct principal cells and mediates the antidiuretic action of AVP by accelerating water reabsorption, thereby playing a vital role in controlling water homeostasis. Moreover, numerous gain-of-function and loss-of-function mutations of V2R have been identified and are closely associated with human diseases, including nephrogenic syndrome of inappropriate diuresis (NSIAD) and X-linked congenital nephrogenic diabetes insipidus (NDI). Thus, V2R has attracted intense interest as a drug target. However, due to a lack of structural information, how AVP recognizes and activates V2R remains elusive, which hampers the V2R-targeted drug design. Here, we determined a 2.6 Ă
resolution cryo-EM structure of the full-length, G s -coupled human V2R bound to AVP (Fig. 1a; Supplementary information, Table S1). The G s protein was engineered based on mini-G s that was used in the crystal structure determination of the G s -coupled adenosine A 2A receptor (A 2A R) to stabilize the V2RâG s protein complex (Supplementary information, Data S1). The final structure of the AVPâV2RâG s complex contains all residues of AVP (residues 1â9), the GÎą s Ras-like domain, Gβγ subunits, Nb35, scFv16, and the V2R residues from T31 to L339 8.57 (superscripts refer to BallesterosâWeinstein numbering). The majority of amino acid side chains, including AVP, transmembrane domain (TMD), all flexible intracellular loops (ICLs) and extracellular loops (ECLs) except for ICL3 and G185âG188 in ECL2, were well resolved in the model, refined against the EM density map (Fig. 1a; Supplementary information, Figs. S1â3). The complex structure can provide detailed information on the binding interface between AVP and helix bundle of the receptor, as well as the receptorâG s interface
Multimodal transformer augmented fusion for speech emotion recognition
Speech emotion recognition is challenging due to the subjectivity and ambiguity of emotion. In recent years, multimodal methods for speech emotion recognition have achieved promising results. However, due to the heterogeneity of data from different modalities, effectively integrating different modal information remains a difficulty and breakthrough point of the research. Moreover, in view of the limitations of feature-level fusion and decision-level fusion methods, capturing fine-grained modal interactions has often been neglected in previous studies. We propose a method named multimodal transformer augmented fusion that uses a hybrid fusion strategy, combing feature-level fusion and model-level fusion methods, to perform fine-grained information interaction within and between modalities. A Model-fusion module composed of three Cross-Transformer Encoders is proposed to generate multimodal emotional representation for modal guidance and information fusion. Specifically, the multimodal features obtained by feature-level fusion and text features are used to enhance speech features. Our proposed method outperforms existing state-of-the-art approaches on the IEMOCAP and MELD dataset
Assisted reproductive technology and interactions between serum basal FSH/LH and ovarian sensitivity index
ObjectivesThis study aimed to investigate whether the FSH (follicle-stimulating hormone)/LH (Luteinizing hormone) ratio correlates with ovarian response in a cross-sectional retrospective study of a population with normal levels of anti-MĂźllerian hormone (AMH).MethodsThis was a retrospective crossâsectional study with data obtained from medical records from March 2019 to December 2019 at the reproductive center in the Affiliated Hospital of Southwest Medical University. The Spearmans correlation test evaluated correlations between Ovarian sensitivity index (OSI) and other parameters. The relationship between basal FSH/LH and ovarian response was analyzed using smoothed curve fitting to find the threshold or saturation point for the population with mean AMH level (1.1<AMH<6Îźg/L). The enrolled cases were divided into two groups according to AMH threshold. Cycle characteristics, cycle information and cycle outcomes were compared. The Mann-Whitney U test was used to compare different parameters between two groups separated by basal FSH/LH in the AMH normal group. Univariate logistic regression analysis and multivariate logistic regression analysis were performed to find the risk factor for OSI.ResultsA total of 428 patients were included in the study. A significant negative correlation was observed between OSI and age, FSH, basal FSH/LH, Gn total dose, and Gn total days, while a positive correlation was found with AMH, AFC, retrieved oocytes, and MII egg. In patients with AMH <1.1 ug/L, OSI values decreased as basal FSH/LH levels increased, while in patients with 1.1<AMH<6 ug/L, OSI values remained stable with increasing basal FSH/LH levels. Logistic regression analysis identified age, AMH, AFC, and basal FSH/LH as significant independent risk factors for OSI.ConclusionsWe conclude that increased basal FSH/LH in the AMH normal group reduces the ovarian response to exogenous Gn. Meanwhile, basal FSH/LH of 3.5 was found to be a useful diagnostic threshold for assessing ovarian response in people with normal AMH levels. OSI can be used as an indicator of ovarian response in ART treatment
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