229 research outputs found
Numerical investigations on scour and flow around two crossing pipelines on a sandy seabed
When a pipeline is laid on the seabed, local scour often occurs below it due to sea currents. In practical engineering, there are some cases that two pipelines laid on the seabed need to cross with each other. The complex flow structures around two crossing pipelines make the scour characteristics different from that of an isolated single pipeline. In this study, scour below two crossing pipelines was simulated numerically using the CFD software Flow-3D. The study is focused on the effect of the intersecting angle on the equilibrium depth and time scale of scour below the crossing position. Five intersecting angles, i.e., α = 0◦ , 15◦ , 30◦ , 45◦ and 90◦ , are considered, where α = 0◦ and 90◦ represent two pipelines parallel and perpendicular to each other, respectively. The results show that the equilibrium depth and the time scale of scour below the two crossing pipelines are greater than those of an isolated single pipeline. The equilibrium depth and time scale of scour have the largest values at α = 0◦ and decrease with the increase of the intersecting angle. Finally, the flow structures around the crossing pipelines are presented to explain the scour process
Does anxiety cause angina recurrence after percutaneous coronary intervention in patients with STEMI?
BackgroundStatistics show that approximately 70% of patients with acute ST-segment elevation myocardial infarction (STEMI) experience relief from chest pain symptoms within 48 h post-percutaneous coronary intervention (PCI). However, over 30% of these patients still suffer from angina post-PCI during their hospital stay and after discharge. Although the interrelation between cardiovascular diseases and psychological states, notably anxiety and stress, has been extensively studied and acknowledged, the specific influence of anxiety disorders on post-PCI clinical outcomes for STEMI patients, especially the recurrence of angina, remains undefined.MethodsThis study included a total of 324 STEMI patients who underwent PCI treatment due to chest pain in our hospital. Baseline and surgical data for all patients were collected. During their hospital stay, patients’ emotional states were assessed using the Hamilton Anxiety Scale, while angina was evaluated using the Seattle Angina Questionnaire. All patients were followed up for 6 months post-discharge to gather clinical data and outcomes, analyzing whether anxiety disorders would affect the recurrence of angina post-PCI in STEMI patients.ResultsOut of the 324 patients, 82 experienced recurrent angina symptoms within 6 months post-PCI discharge. Compared to the non-recurrence group, the recurrence group showed statistically significant differences in anxiety levels. Other differing factors included the spouse's health status, cardiac Killip classification, severity of coronary lesions, and the state of the coronary microcirculation. After utilizing propensity score matching to eliminate inherent biases between the two groups at a 1:1 ratio, the COX regression analysis indicated that a patient's anxiety status is a risk factor for the occurrence of angina post-PCI in STEMI patients (HR = 2.094, 95% CI = 1.248–3.514, P = 0.005).ConclusionAnxiety is a significant factor for short-term recurrence of angina post-PCI in STEMI patients. This further confirms the crucial impact of mental health on cardiovascular wellness
Performance and sustainability evaluation of rural digitalization and its driving mechanism: evidence from Hunan province of China
Quantitatively measuring rural digitalization performance and development sustainability, identifying their key influencing factors and figuring out their driving mechanisms are of great value to policy design for rural revitalization and management. This paper analyzed the sustainable development degree, spatial patterns, and influencing factors of rural digitization in Hunan Province, China, based on a combination of PSR, TOPSIS, ESDA, GWR and GeoDetector, in an attempt to provide a basis for the planning and policy design of rural management. The sustainability and construction performance of rural digitalization in Hunan were characterized by significant spatial inequality and positive autocorrelation, with coefficients of variation of 0.33 and 0.24, and Moran’s I values of 0.29 and 0.34, respectively. The rural digitalization in Hunan showed significant non-equilibrium across different dimensions and brought forward diversified combination patterns, including single dimensional leadership, dual dimensional leadership, three-dimensional leadership, and all-round development. The pattern dual dimensional leadership, especially PS (pressure + state), was dominant in the sustainability of rural digitalization, compared to the pattern single dimensional leadership dominant in the construction performance, especially I (rural infra-structure digitalization), IL (rural infrastructure + life digitalization), IG (rural infrastructure + governance digitalization). The sustainability and construction performance of rural digitalization in Hunan were subject to a complex driving mechanism, with different factors differing significantly in their action nature, force, spatial effects and interactions. Notably, economic development (gross domestic product) is a positive key factor, while government intervention capacity (fiscal self-sufficiency rate) is an important factor, and natural environment (relief amplitude) is a mixed auxiliary factor (both positive and negative). Factor interactions were mainly characterized by nonlinear enhancement and a large number of super factor pairs. Therefore, the policy design should take into account both localized and differentiated management; and also emphasize enhanced cooperation with adjacent counties and synergistic management. It is suggested to divide Hunan into four planning zonings of leading, potential, warning and general zone, and design the spatial policies for each of them according to the driving mechanism, so as to develop a more reasonable and practical combination of development projects and management policies
Overexpression of Peptide-Encoding OsCEP6.1 Results in Pleiotropic Effects on Growth in Rice (O. sativa)
Plant peptide hormone plays an important role in regulating plant developmental programs via cell-to-cell communication in a non-cell autonomous manner. To characterize the biological relevance of C-TERMINALLY ENCODED PEPTIDE (CEP) genes in rice, we performed a genome-wide search against public databases using bioinformatics approach and identified six additional CEP members. Expression analysis revealed a spatial-temporal pattern of OsCEP6.1 gene in different tissues and at different developmental stages of panicle. Interestingly, the expression level of the OsCEP6.1 was also significantly up-regulated by exogenous cytokinin. Application of a chemically synthesized 15-amino-acid OsCEP6.1 peptide showed that OsCEP6.1 had a negative role in regulating root and seedling growth, which was further confirmed by transgenic lines. Furthermore, the constitutive expression of OsCEP6.1 was sufficient to lead to panicle architecture and grain size variations. Scanning electron microscopy analysis revealed that the phenotypic variation of OsCEP6.1 overexpression lines resulted from decreased cell size but not reduced cell number. Moreover, starch accumulation was not significantly affected. Taken together, these data collectively suggest that the OsCEP6.1 peptide might be involved in regulating the development of panicles and grains in rice
MAP4K family kinases act in parallel to MST1/2 to activate LATS1/2 in the Hippo pathway.
The Hippo pathway plays a central role in tissue homoeostasis, and its dysregulation contributes to tumorigenesis. Core components of the Hippo pathway include a kinase cascade of MST1/2 and LATS1/2 and the transcription co-activators YAP/TAZ. In response to stimulation, LATS1/2 phosphorylate and inhibit YAP/TAZ, the main effectors of the Hippo pathway. Accumulating evidence suggests that MST1/2 are not required for the regulation of YAP/TAZ. Here we show that deletion of LATS1/2 but not MST1/2 abolishes YAP/TAZ phosphorylation. We have identified MAP4K family members--Drosophila Happyhour homologues MAP4K1/2/3 and Misshapen homologues MAP4K4/6/7-as direct LATS1/2-activating kinases. Combined deletion of MAP4Ks and MST1/2, but neither alone, suppresses phosphorylation of LATS1/2 and YAP/TAZ in response to a wide range of signals. Our results demonstrate that MAP4Ks act in parallel to and are partially redundant with MST1/2 in the regulation of LATS1/2 and YAP/TAZ, and establish MAP4Ks as components of the expanded Hippo pathway
A Spacer Cation Assisted Nucleation and Growth Strategy Enables Efficient and High‐Luminance Quasi‐2D Perovskite LEDs
Quasi‐2D Ruddlesden‐Popper perovskites receive tremendous attention for application in light‐emitting diodes (LEDs). However, the role of organic ammonium spacers on perovskite film has not been fully‐understood. Herein, a spacer cation assisted perovskite nucleation and growth strategy, where guanidinium (GA+) spacer is introduced into the perovskite precursor and at the interface between the hole transport layer (HTL) and the perovskite, to achieve dense and uniform perovskite films with enhanced optical and electrical performance is developed. A thin GABr interface pre‐formed on HTL provides more nucleation sites for perovskite crystal; while the added GA+ in perovskite reduces the crystallization rate due to strong hydrogen bonding interacts with intermediates, which promotes the growth of enhanced‐quality quasi‐2D perovskite films. The ionized ammonium group ( NH3+) of GA+ also favors formation of polydisperse domain distribution, and amine or imine ( NH2 or NH) group interact with perovskite defects through coordination bonding. The spacer cation assisted nucleation and growth strategy is advantageous for producing efficient and high‐luminance perovskite LEDs, with a peak external quantum efficiency of over 20% and a luminance up to 100 000 cd m−2. This work can inform and underpin future development of high‐performance perovskite LEDs with concurrent high efficiency and brightness
Constructing Synergistic Triazine and Acetylene Cores in Fully Conjugated Covalent Organic Frameworks for Cascade Photocatalytic H2O2 Production
Covalent organic frameworks (COFs) are an ideal template for photocatalytic H2O2 synthesis because of the tunable chemical structures and semiconductor properties. However, the photoactivity for COFs is still under-improved due to the inefficient intrinsic charge generation, fast recombination of photogenerated charges, and limited electron transport along the frameworks. Herein, spatially separated and synergistic triazine and acetylene units are first integrated into COFs (EBA-COF and BTEA-COF) for photocatalytic H2O2 production. The spatial separation of triazine and acetylene cores leads to efficient charge separation and suppressed charge recombination, and C═C linkage facilitates electrons transport over the skeletons. Both experimental and computational results suggested that triazine and acetylene units synergistically promote H2O2 synthesis in a two-electron pathway. The EBA-COF showed an attractive activity with a H2O2 production rate of 1830 μmol h-1 gcat-1, superior to that of most other COF-based catalysts. This study provides a method for designing photocatalysts with synergistic photocatalytic active sites based on vinylene-linked COFs
Liposome encapsulated Disulfiram inhibits NFκB pathway and targets breast cancer stem cells in vitro and in vivo
Breast cancer stem cells (BCSCs) are pan-resistant to different anticancer agents
and responsible for cancer relapse. Disulfiram (DS), an antialcoholism drug, targets
CSCs and reverses pan-chemoresistance. The anticancer application of DS is limited
by its very short half-life in the bloodstream. This prompted us to develop a liposomeencapsulated
DS (Lipo-DS) and examine its anticancer effect and mechanisms in vitro
and in vivo.
The relationship between hypoxia and CSCs was examined by in vitro comparison
of BC cells cultured in spheroid and hypoxic conditions. To determine the importance
of NFκB activation in bridging hypoxia and CSC-related pan-resistance, the CSC
characters and drug sensitivity in BC cell lines were observed in NFκB p65 transfected
cell lines. The effect of Lipo-DS on the NFκB pathway, CSCs and chemosensitivity was
investigated in vitro and in vivo.
The spheroid cultured BC cells manifested CSC characteristics and pan-resistance
to anticancer drugs. This was related to the hypoxic condition in the spheres. Hypoxia
induced activation of NFκB and chemoresistance. Transfection of BC cells with NFκB
p65 also induced CSC characters and pan-resistance. Lipo-DS blocked NFκB activation
and specifically targeted CSCs in vitro. Lipo-DS also targeted the CSC population in
vivo and showed very strong anticancer efficacy. Mice tolerated the treatment very
well and no significant in vivo nonspecific toxicity was observed.
Hypoxia induced NFκB activation is responsible for stemness and chemoresistance
in BCSCs. Lipo-DS targets NFκB pathway and CSCs. Further study may translate DS
into cancer therapeutics
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
- …