214 research outputs found
Initial-boundary value problem for 2D temperature-dependent tropical climate model
It is well known that the tropical climate model is an important model to
describe the interaction of large scale flow fields and precipitation in the
tropical atmosphere. In this paper, we address the issue of global
well-posedness for 2D temperature-dependent tropical climate model in a smooth
bounded domain. Through classical energy estimates and De Giorgi-Nash-Moser
iteration method, we obtain the global existence and uniqueness of strong
solution in classical energy spaces. Compared with Cauchy problem, we establish
more delicate a priori estimates with exponential decay rates. To the best of
our knowledge, this is the first result concerning the global well-posedness
for the initial-boundary value problem in 2D tropical climate model.Comment: 20 page
Asymptotic stability for -dimensional isentropic compressible MHD equations without magnetic diffusion
Whether the global well-posedness of strong solutions of -dimensional
compressible isentropic magnetohydrodynamic (MHD for short) equations without
magnetic diffusion holds true or not remains an challenging open problem, even
for the small initial data. In recent years, stared from the pioneer work by Wu
and Wu [Adv. Math. 310 (2017), 759--888], much more attention has been paid to
the system when the magnetic field near an equilibrium state (the background
magnetic field for short). In particular, when the background magnetic field
satisfies the Diophantine condition (see (1.3) for details), Wu and Zhai [Math.
Models Methods Appl. Sci. 33 (2023), no. 13, 2629--2656] established the decay
estimates and asymptotic stability for smooth solutions of the 3D compressible
isentropic MHD system without magnetic diffusion in
with by exploiting a wave structure. In this paper, a new dissipative
mechanism is found out and applied so that we can improve the spaces where the
decay estimates and asymptotic stability of solutions are taking place by Wu
and Zhai. More precisely, we establish the decay estimates of solutions in
and asymptotic stability result in
for any dimensional periodic domain
with and . Our results provide an approach for
establishing the decay estimates and asymptotic stability in the Sobolev spaces
with much lower regularity and uniform dimension, which can be used to study
many other related models such as the compressible non-isentropic MHD system
without magnetic diffusion and so on.Comment: 39 page
Sharp decay estimates and asymptotic stability for incompressible MHD equations without viscosity or magnetic diffusion
Whether the global existence and uniqueness of strong solutions of
-dimensional incompressible magnetohydrodynamic (MHD for short) equations
with only kinematic viscosity or magnetic diffusion holds true or not remains
an outstanding open problem. In recent years, more attention has been paid to
the case when the magnetic field close to an equilibrium state (the background
magnetic field for short). Specifically, when the background magnetic field
satisfies the Diophantine condition (see (1.2) for details), Chen, Zhang and
Zhou [Sci. China Math. 41 (2022), pp.1-10] first studied the perturbation
system and established the decay estimates and stability of its solutions in 3D
periodic domain , which was then improved to
for 2D periodic domain
and any , by Zhai [J. Differ. Equ. 374
(2023), pp.267-278]. In this paper, we seek to find the optimal decay estimates
and improve the space where the global stability is taking place. Through
deeply exploring and fully utilizing the structure of perturbation system, we
discover a new dissipative mechanism, which enables us to establish the decay
estimates in Sobolev space with much lower regularity. Based on the above
discovery, we greatly reduce the initial regularity requirement of
aforementioned two works from and
to
for when and respectively.
Additionally, we first present the linear stability result via the method of
spectral analysis in this paper. From which, the decay estimates obtained for
the nonlinear system can be seen as sharp in the sense that they are in line
with those for the linearized system.Comment: 24 page
Tn5AraOut mutagenesis for the identification of Yersinia pestis genes involved in resistance towards cationic antimicrobial peptides
Bacterial pathogens display a variety of protection mechanisms against the inhibitory and lethal effects of host cationic antimicrobial peptides (CAMPs). To identify Yersinia pestis genes involved in CAMP resistance, libraries of DSY101 (KIM6 caf1 pla psa) minitransposon Tn5AraOut mutants were selected at 37°C for resistance to the model CAMPs polymyxin B or protamine. This approach targeted genes that needed to be repressed (null mutations) or induced (upstream P(BAD) insertions) for the detection of CAMP resistance, and predictably for improved pathogen fitness in mammalian hosts. Ten mutants demonstrated increased resistance to polymyxin B or protamine, with the mapped mutations pointing towards genes suspected to participate in modifying membrane components, genes encoding transport proteins or enzymes, or the regulator of a ferrous iron uptake system (feoC). Not all the mutants were resistant to both CAMPs used for selection. None of the polymyxin B- and only some protamine-resistant mutants, including the feoC mutant, showed increased resistance to rat bronchoalveolar lavage fluid (rBALF) known to contain cathelicidin and β-defensin 1. Thus, findings on bacterial resistance to polymyxin B or protamine don't always apply to CAMPs of the mammalian innate immune system, such as the ones in rBALF.Fil: Guo, Jitao. Peking University Health Science Center. Department of Microbiology; ChinaFil: Nair, Manoj K. M.. University of Pennsylvania. School of Veterinary Medicine; Estados UnidosFil: Galvan, Estela Maria. Fundación Instituto Leloir; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquimicas de Buenos Aires; Argentina. University of Pennsylvania; Estados UnidosFil: Liu, Shu Lin. Peking University Health Science Center. Department of Microbiology; ChinaFil: Schifferli, Dieter M.. University of Pennsylvania. School of Veterinary Medicine; Estados Unido
Efficacy of mirabegron for ureteral stones: a systematic review with meta-analysis of randomized controlled trials
Background: Medical expulsive therapy demonstrates efficacy in managing ureteral stones in patients amenable to conservative interventions. This meta-analysis aims to evaluate the effectiveness of mirabegron in the treatment of ureteral stones.Methods: From conception to November 2023, we examined PubMed databases, the Cochrane Library, Embase, Ovid, Scopus, and trial registries for this systematic review and meta-analysis. We chose relevant randomized controlled trials (RCTs) evaluating the efficacy of mirabegron as an expulsive treatment for ureteral stones. The Cochrane risk of bias method was used to assess the quality of the evidence. Outcome measures, which included the stone expulsion rate (SER), expulsion time, and pain episodes, were analyzed using RevMan 5.4 and Stata 17.Results: Seven RCTs (N = 701) had enough information and were ultimately included. In patients with ureteral stones, mirabegron-treated patients had a substantially higher SER [odds ratio (OR) = 2.57, 95% confidence interval (CI) = 1.41–4.68, p = 0.002] than placebo-treated patients. Subgroup analysis revealed that mirabegron was superior to placebo in patients with small ureteral stones (OR = 2.26, 95% CI = 1.05–4.87, p = 0.04), with no heterogeneity between studies (p = 0.54; I2 = 0%). Mirabegron patients had a higher SER than the control group for distal ureteral stones (DUSs) (OR = 2.48, 95% CI = 1.31–4.68, p = 0.005). However, there was no difference in stone ejection time or pain episodes between groups.Conclusion: Mirabegron considerably improves SER in patients with ureteral stones, and the effect appears to be more pronounced for small and DUSs. Nevertheless, mirabegron treatment was not associated with improved stone expulsion time or pain management
Wiskott-Aldrich syndrome gene as a prognostic biomarker correlated with immune infiltrates in clear cell renal cell carcinoma
IntroductionThe abnormal expression of the Wiskott-Aldrich syndrome protein (WASP) encoded by the Wiskott-Aldrich syndrome (WAS) gene has been implicated in tumor invasion and immune regulation. However, prognostic implications of WAS and its correlation tumor infiltrating in renal clear cell carcinoma (ccRCC) is not clear cut.MethodsThe correlation between WAS expression, clinicopathological variables and clinical outcomes were evaluated using The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), Tumor Immune Estimation Resource (TIMER), UALCAN, Gene Expression Profiling Interaction Analysis (GEPIA), Kaplan-Meier (KM) plotter and other databases. Furthermore, we assessed the transcription expression of WAS in renal cancer tissues, various renal carcinoma cell lines and human renal tubular cells (HK2) using quantitative polymerase chain reaction (qPCR). A comprehensive analysis of multiple databases including TIMER, GEPIA, TISIDB, ESTIMATE algorithm, and CIBERSORT algorithm were performed to determine the correlation between WAS and tumor infiltrating immune cells in ccRCC.ResultsThe results displayed an increase in WAS mRNA level in ccRCC compared to normal tissue. WAS protein level was found highly expressed in cancer tissues, particularly within renal tumor cells via the human protein atlas (HPA). Interestingly, we found that elevated WAS expression was significantly positively correlated with the infiltration of CD8+ T cells, B cells, Monocytes, Neutrophils, Macrophages, T cell regulation, NK cells, and Dendritic cells in ccRCC. Bioinformatics demonstrated a strong correlation between WAS expression and 42 immune checkpoints, including the T cell exhaustion gene PD-1, which is critical for exploring immunotherapy for ccRCC. We revealed that patients with high WAS expression were less sensitive to immunotherapy medications.ConclusionIn conclusion, our study identified that WAS was a prognostic biomarker and correlated with immune infiltrates in ccRCC
Research progress on the microbiota in bladder cancer tumors
The microbiota, also referred to as the microbial community, is a crucial component of the human microenvironment. It is located predominantly in various organs, including the intestines, skin, oral cavity, respiratory tract, and reproductive tract. The microbiota maintains a symbiotic relationship with the human body, influencing physiological and pathological functions to a significant degree. There is increasing evidence linking the microbial flora to human cancers. In contrast to the traditional belief that the urethra and urine of normal individuals are sterile, recent advancements in high-throughput sequencing technology and bacterial cultivation methods have led to the discovery of specific microbial communities in the urethras of healthy individuals. Given the prevalence of bladder cancer (BCa) as a common malignancy of the urinary system, researchers have shifted their focus to exploring the connection between disease development and the unique microbial community within tumors. This shift has led to a deeper investigation into the role of microbiota in the onset, progression, metastasis, prognosis, and potential for early detection of BCa. This article reviews the existing research on the microbiota within BCa tumors and summarizes the findings regarding the roles of different microbes in various aspects of this disease
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