The focus of this study is to explore the thermodynamic characteristics of an intermediate heat-exchange cycle (IHEC) system in aero engines, employing experimental analysis. Using air, fuel, and ...intermediate working fluid (IWF) as working mediums, an IHEC system experimental platform incorporated two heat exchangers (HEX) was established. A theoretical analysis model for characteristics of the IHEC system was developed using the heat current method and a novel method for estimating the overall heat transfer coefficient (K). Deviations between experimental and simulation results for system equilibrium heat transfer rates and temperatures at each node of the IHEC system are within ±10%, and the maximum average relative deviation of the proposed method for estimating K is −7.93%. Detailed analyses have been conducted regarding the effects of fuel mass flow rate, IWF mass flow rate, air mass flow rate, and air inlet temperature on the system. Raising the fuel mass flow rate leads to reduced temperatures at each system node, while the system's equilibrium heat transfer rate initially increases and then stabilizes. Variations in IWF mass flow rate have complex impacts on the IHEC system, influenced by HEX design margins and heat transfer capacities. Tailored analyses are necessary based on specific circumstances.
•A theoretical analysis model for system-level characteristics of the IHEC system was developed.•A two-stage heat exchanger combined IHEC system experimental platform was established.•Different parameter's effects on systematic thermodynamic performance have been conducted.•The accuracy of the mathematical model was verified by experiments.
When different species experience similar selection pressures, the probability of evolving similar adaptive solutions may be influenced by legacies of evolutionary history, such as lineage-specific ...changes in genetic background. Here we test for adaptive convergence in hemoglobin (Hb) function among high-altitude passerine birds that are native to the Qinghai-Tibet Plateau, and we examine whether convergent increases in Hb–O₂ affinity have a similar molecular basis in different species. We documented that high-altitude parid and aegithalid species from the Qinghai-Tibet Plateau have evolved derived increases in Hb–O₂ affinity in comparison with their closest lowland relatives in East Asia. However, convergent increases in Hb–O₂ affinity and convergence in underlying functional mechanisms were seldom attributable to the same amino acid substitutions in different species. Using ancestral protein resurrection and site-directed mutagenesis, we experimentally confirmed two cases in which parallel substitutions contributed to convergent increases in Hb–O₂ affinity in codistributed high-altitude species. In one case involving the ground tit (Parus humilis) and gray-crested tit (Lophophanes dichrous), parallel amino acid replacements with affinity-enhancing effects were attributable to nonsynonymous substitutions at a CpG dinucleotide, suggesting a possible role for mutation bias in promoting recurrent changes at the same site. Overall, most altitude-related changes in Hb function were caused by divergent amino acid substitutions, and a select few were caused by parallel substitutions that produced similar phenotypic effects on the divergent genetic backgrounds of different species.
Formation of suitable amount of metallic conductive HxWO3 on WO3 facilitates the transfer of electrons, leading to efficient charge separation and hence resulting in the enhancement of the ...photocatalytic O2 evolution activity under visible light irradiation.
•The photocatalytic O2 evolution activity of hydrogen-treated WO3 is enhanced more than twice compared to the pristine WO3.•Hydrogen treatment of WO3 generates a kind of HxWO3–WO3 composite on the surface layer of WO3.•The electrical conductive HxWO3 phase plays as a role of reduction cocatalyst for WO3.
The photocatalytic O2 evolution from water oxidation was investigated over a series of WO3 materials treated with hydrogen at different temperatures. The activity of WO3 treated with hydrogen at 200°C can be enhanced to 2.3 times of that of pristine WO3. The surface WO3 layer is partially reduced during the hydrogen treatment, forming a kind of HxWO3–WO3 composite material. The HxWO3 phase possesses high electrical conductivity and plays as a reduction cocatalyst for WO3 in the photocatalytic process. Formation of suitable amount of HxWO3 could facilitate the transfer of electrons, leading to efficient charge separation of WO3 and resulting in the enhancement of the photocatalytic O2 evolution activity under visible light irradiation. Fabrication of semiconductor and conductor nanocomposite might be a useful strategy for the development of efficient water-splitting photocatalysts.
The cerebellum is essential for motor control and cognitive functioning, engaging in bidirectional communication with the cerebral cortex. The common marmoset, a small non-human primate, offers ...unique advantages for studying cerebello-cerebral circuits. However, the marmoset cerebellum is not well described in published resources. In this study, we present a comprehensive atlas of the marmoset cerebellum comprising (1) fine-detailed anatomical atlases and surface-analysis tools of the cerebellar cortex based on ultra-high-resolution ex vivo MRI, (2) functional connectivity and gradient patterns of the cerebellar cortex revealed by awake resting-state fMRI, and (3) structural-connectivity mapping of cerebellar nuclei using high-resolution diffusion MRI tractography. The atlas elucidates the anatomical details of the marmoset cerebellum, reveals distinct gradient patterns of intra-cerebellar and cerebello-cerebral functional connectivity, and maps the topological relationship of cerebellar nuclei in cerebello-cerebral circuits. As version 5 of the Marmoset Brain Mapping project, this atlas is publicly available at https://marmosetbrainmapping.org/MBMv5.html.
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•Detailed anatomical atlases and surfaces of the cerebellum based on ultra-high-resolution MRI•Distinct patterns of the intra-cerebellar and the cerebello-cerebral functional gradients•Functional connectivity patterns between the cerebellar cortex and the functional networks•Connectivity topology of the cerebellar nuclei to the cerebellar cortex and the neocortex
Zhu et al. present a marmoset cerebellum atlas, revealing anatomical details, functional connectivity patterns, and cerebellar nuclei topological relationships in cerebello-cerebral circuits. Using ultra-high-resolution ex vivo MRI and awake resting-state fMRI, this study provides resources and atlas tools to advance understanding of cerebello-cerebral circuits in non-human primates.
Objectives‘National Special Stewardship in the Clinical Use of Antibiotics’ was put forward in July 2011 in China. We aimed to retrospectively evaluate the impact of antimicrobial stewardship (AMS) ...managed by clinical pharmacists on antibiotic utilisation, prophylaxis and antimicrobial resistance (AMR).DesignThis was a retrospective observational study of trends in antibiotic use and AMR in the context of AMS.SettingBeijing Chaoyang Hospital, a 1400-bed tertiary hospital, in China.Data and participantsAntibiotic prescriptions from 820 doctors included all outpatients (n=17 766 637) and inpatients (n=376 627) during 2010–2016. Bacterial resistance data were from all inpatients (n=350 699) during 2011–2016.InterventionsMultiaspect intervention measures were implemented by clinical pharmacists (13 persons), for example, formulating the activity programme and performance management, advising on antibacterial prescriptions and training.Outcome measuresThe proportion of antibiotic prescriptions among outpatients and inpatients, intensity of consumption in defined daily dose (DDD)/100 bed-days, antibiotic prophylaxis in type I incision operations and resistance rates of Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa were retrospectively analysed.ResultsThe proportion of antibiotic prescriptions decreased in outpatients (from 19.38% to 13.21%) and in inpatients (from 64.34% to 34.65%), the intensity of consumption dropped from 102.46 to 37.38 DDD/100 bed-days. The proportion of antibiotic prophylaxis decreased from 98.94% to 18.93%. The proportion of rational timing of initial dose increased from 71.11% to 96.74%, the proportion of rational duration rose from 2.84% to 42.63%. Time series analysis demonstrated the resistance rates of E. coli and P. aeruginosa to fluoroquinolones decreased, the incidence rate of methicillin-resistant Staphylococcus aureus also decreased, whereas the resistance rates of E. coli and K. pneumoniae to carbapenems increased. The antibiotic use was partly positively correlated with AMR.ConclusionsAMS had an important role in reducing antibiotic use and surgical antibiotic prophylaxis. The AMR was positively correlated with antibiotic consumption to some extent.
Acute lung injury (ALI) is characterized by overwhelming lung inflammation and anti-inflammation treatment is proposed to be a therapeutic strategy for ALI. Poly (ADP-ribose) polymerase-1 has been ...demonstrated to be involved in tissue inflammation and one of its inhibitors, 3, 4-Dihydro-54-(1-piperindinyl)butoxy-1(2H)-isoquinoline (DPQ), exerts anti-inflammatory effect. However, it is still unclear whether the DPQ possesses the protective effect on ALI and what mechanisms are involved. In this study, we tested the effect of DPQ on the lung inflammation induced by lipopolysaccharide (LPS) challenge in mice. We found that 6 h-LPS challenge induced significant lung inflammation and vascular leakage in mice. Treatment with DPQ at the dose of 10 μg/kg markedly reduced the neutrophil infiltration, myeloperoxidase activity and up-regulation of pro-inflammatory mediators and cytokines. LPS-elevated vascular permeability was decreased by DPQ treatment, accompanied by the inhibition of apoptotic cell death in mice lungs. In addition, we isolated mice peritoneal macrophages and showed pretreatment with DPQ at 10 μM inhibited the production of cytokines in the macrophages following LPS stimulation. DPQ treatment also inhibited the phosphorylation and degradation of IκB-α, subsequently blocked the activation of nuclear factor (NF)-κB induced by LPS in vivo and in vitro. Taken together, our results show that DPQ treatment inhibits NF-κB signaling in macrophages and protects mice against ALI induced by LPS, suggesting inhibition of Poly (ADP-ribose) polymerase-1 may be a potential and effective approach to resolve inflammation for the treatment of ALI.
Carbon dots (CDs) exhibit a wide range of desirable properties including excellent photoluminescence, photostability, and water solubility, making them ideally suitable for use in the context of drug ...delivery, bioimaging, and related biomedical applications. Before these CDs can be translated for use in humans, however, further research regarding their in vivo toxicity is required. Owing to their low cost, rapid growth, and significant homology to humans, zebrafish (
) are commonly employed as in vivo model systems in the toxicity studies of nanomaterials. In the present report, our group employed a hydrothermal approach to synthesize CDs and then assessed their toxicity in zebrafish. The resultant CDs were roughly 2.4 nm spheroid particles that emitted strong blue fluorescence in response to the excitation at 365 nm. These CDs did not induce any evident embryonic toxicity or did cause any apparent teratogenic effects during hatching or development when dosed at 150 μg/mL. However, significant effects were observed in zebrafish embryos at CD concentrations >200 μg/mL, including pericardial and yolk sac edema, delayed growth, spinal cord flexure, and death. These high CD concentrations were further associated with the reduction in zebrafish larval locomotor activity and decreased dopamine levels, reduced frequencies of tyrosine hydroxylase-positive dopaminergic neurons, and multiple organ damage. Further studies will be required to fully understand the mechanistic basis for CD-mediated neurotoxicity, with such studies being essential to fully understand the translational potential of these unique nanomaterials.
Phosphodiesterase 4 (PDE4) hydrolyzes cyclic adenosine monophosphate (cAMP) and plays a vital roles in many biological processes. PDE4 inhibitors have been widely studied as therapeutics for the ...treatment of various diseases, including asthma, chronic obstructive pulmonary disease (COPD) and psoriasis. Many PDE4 inhibitors have progressed to clinical trials and some have been approved as therapeutic drugs. Although many PDE4 inhibitors have been approved to enter clinical trials, however, the development of PDE4 inhibitors for the treatment of COPD or psoriasis has been hampered by their side effects of emesis. Herein, this review summarizes advances in the development of PDE4 inhibitors over the last ten years, focusing on PDE4 sub-family selectivity, dual target drugs, and therapeutic potential. Hopefully, this review will contribute to the development of novel PDE4 inhibitors as potential drugs.
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•Phosphodiesterase 4 (PDE4) plays a vital roles in many biological processes.•Summarize the PDE4 inhibitors in clinical trials.•Summary activity relationship (SAR) analyses.•Summary of IC50 values and kinetic studies of PDE4 inhibitors.
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