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    Uniform cooling for concentrator photovoltaic cell by micro-encapsulated phase change material slurry in double-layered minichannels

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    The concentrator photovoltaic (CPV) systems often suffer high heat flux, leading to cell temperatures rising, which will affect its performance and reduce the service life. Double-layered minichannel heat sink (DL-MCHS) is an efficient cooling technology, which could effectively lower down the top temperature of CPV cell. Micro-encapsulated phase change material slurry (MPCS) is a novel type of latent heat functional fluid and has a good application prospect in the field of cooling. Therefore, MPCS flowing in the DL-MCHS, as the thermal management device was investigated for the cooling of CPV cell. Three configurations of minichannels, including staggered arrangement, parallel arrangement and dual unequal arrangement were compared and optimized. On the basis of optimization, the flow and heat transfer performance of MPCS with different concentrations in double-layered straight and wavy minichannels had been numerically studied. The results indicated that the lowest top temperature of dual unequal DL-MCHS obtained by counter arrangement could be reduced by 0.56 °C compared with the parallel arrangement at Re = 152. Both the ΔP and h were significantly influenced by concentrations. When Re reached 262, ΔP of 5 wt% MPCS in wave minichannel with 5 mm wavelength was 44 % larger than that of pure water in straight minichannel, which would consume more pumping power. However, the heat dissipation performance was improved significantly and Nusselt number in double-layered wavy minchannels also increased with the wavelength decreasing. Therefore, Performance Evaluation Criteria (PEC) was proposed to evaluate the overall performance, which was also greatly influenced by particle concentration and channel wavelength. After optimization, the highest PEC of MPCS in the wavy minichannel was achieved to 1.60. Because of the wavy minichannel with concave-convex structure, the obstacle of total thermal resistance became smaller for the wavelength decreasing. These findings of MPCS in minichannel can provide a good theoretical basis and engineering application in the cooling technology of CPV

    Perceptions, definitions, and therapeutic interventions for occasional constipation: a ROME working group consensus document

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    Background & Aims: Functional constipation is the most common of the disorders of gut-brain interaction, affecting approximately 12% of the world population. Although classically considered a chronic condition, many individuals experience shorter yet repetitive bouts of constipation representing a different clinical entity. There has been increased interest in this latter disorder, which has recently been classified as occasional constipation. This Rome Foundation working group document reflects the consensus of an international team of specialists who summarized currently available research to provide a working definition of and treatment algorithm for occasional constipation. The recommendations herein are based on current evidence, accounting for gaps in the literature as well as international variance in definitions and health seeking behaviors for constipation. Methods: The committee members reviewed the scientific literature, focusing specifically on occasional constipation, with the understanding that as a new entity, a paucity of data would be available. We used Rome IV research and clinical definitions to establish the framework for our definition of occasional constipation. Where possible, treatment recommendations were determined on the basis of the earliest extractable data from functional constipation studies, focusing on positive results within the first 2 weeks of treatment. We used the Delphi method to create consensus with 100% agreement between the authors. Results: An evidence-based review of the literature resulted in the definition of occasional constipation as follows: “individuals who experience the presence of at least 1 functional constipation symptom, in the absence of alarm signs or symptoms, occurring at irregular and infrequent intervals, which is bothersome enough to induce a patient to seek medical management.” Medical management whether seeking medical care or self-treatment was left to the individual's discretion, and we did not include time anchors because these thresholds require further investigation. Polyethylene glycol and stimulant laxatives are recommended as first-line interventions, whereas magnesium-containing compounds are suggested in individuals failing to respond to these therapies. There are insufficient data to make recommendations for using fiber or stool softeners. Prescription laxatives should be reserved for individuals with chronic constipation. Conclusions: Occasional constipation is a unique clinical entity characterized by infrequent but recurrent symptoms. Data are limited because consensus definitions have been lacking. Establishing a standardized definition and therapeutic recommendations provides a framework for future studies focusing on epidemiologic and symptoms-based outcomes. Further studies are needed to confirm and refine these recommendations

    Mechanistic insight into the role of AUXIN RESISTANCE4 in trafficking of AUXIN1 and LIKE AUX1-2

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    AUXIN RESISTANCE4 (AXR4) regulates the trafficking of auxin influx carrier AUXIN1 (AUX1), a plasma-membrane protein that predominantly localizes to the endoplasmic reticulum (ER) in the absence of AXR4. In Arabidopsis (Arabidopsis thaliana), AUX1 is a member of a small multigene family comprising 4 highly conserved genes—AUX1, LIKE-AUX1 (LAX1), LAX2, and LAX3. We report here that LAX2 also requires AXR4 for correct localization to the plasma membrane. AXR4 is a plant-specific protein and contains a weakly conserved α/β hydrolase fold domain that is found in several classes of lipid hydrolases and transferases. We have previously proposed that AXR4 may either act as (i) a post-translational modifying enzyme through its α/β hydrolase fold domain or (ii) an ER accessory protein, which is a special class of ER protein that regulates targeting of their cognate partner proteins. Here, we show that AXR4 is unlikely to act as a post-translational modifying enzyme as mutations in several highly conserved amino acids in the α/β hydrolase fold domain can be tolerated and active site residues are missing. We also show that AUX1 and AXR4 physically interact with each other and that AXR4 reduces aggregation of AUX1 in a dose-dependent fashion. Our results suggest that AXR4 acts as an ER accessory protein. A better understanding of AXR4-mediated trafficking of auxin transporters in crop plants will be crucial for improving root traits (designer roots) for better acquisition of water and nutrients for sustainable and resilient agriculture

    ThermoBRET: A Ligand-Engagement Nanoscale Thermostability Assay Applied to GPCRs**

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    Measurements of membrane protein thermostability reflect ligand binding. Current thermostability assays often require protein purification or rely on pre-existing radiolabelled or fluorescent ligands, limiting their application to established targets. Alternative methods, such as fluorescence-detection size exclusion chromatography thermal shift, detect protein aggregation but are not amenable to high-throughput screening. Here, we present a ThermoBRET method to quantify the relative thermostability of G protein coupled receptors (GPCRs), using cannabinoid receptors (CB1 and CB2) and the β2-adrenoceptor (β2AR) as model systems. ThermoBRET reports receptor unfolding, does not need labelled ligands and can be used with non-purified proteins. It uses Bioluminescence Resonance Energy Transfer (BRET) between Nanoluciferase (Nluc) and a thiol-reactive fluorescent dye that binds cysteines exposed by unfolding. We demonstrate that the melting point (Tm) of Nluc-fused GPCRs can be determined in non-purified detergent solubilised membrane preparations or solubilised whole cells, revealing differences in thermostability for different solubilising conditions and in the presence of stabilising ligands. We extended the range of the assay by developing the thermostable tsNLuc by incorporating mutations from the fragments of split-Nluc (Tm of 87 °C versus 59 °C). ThermoBRET allows the determination of GPCR thermostability, which is useful for protein purification optimisation and drug discovery screening

    Mental Health Staff Perspectives on Personal Recovery: A Narrative Study on Positive Professional Impact of Recovery-Oriented Care

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    ObjectivesMental health staff play an important role in facilitating personal recovery. We examined how mental health staff perceived personal recovery and the impact of their experience with supporting personal recovery.Research Design and MethodsForty-eight mental health staff wrote a narrative about a service user with severe mental illness that they believed to be in personal recovery and elaborated on the impact of this professional experience. Interpretive phenomenological analysis was used to illuminate 1) conceptualizations of personal recovery, 2) professional contribution to recovery, and 3) positive impact of recovery-oriented care on staff.ResultsConceptualizations of recovery focused on social connections and positive subjective states, and also symptom remission and illness management. Professional contributions were narrated as encompassing treatment, relationships and conversations as well as time and team collaboration. Impact on the staff included strong positive emotions, professional gains with respect to learning and self-esteem, motivation for and meaning in work as well as belief in recovery.ConclusionsThis latter finding suggests that sharing narratives about service users in personal recovery may increase work pleasure and help reduce burn out in mental health staff

    General Purpose Artificial Intelligence Systems (GPAIS): Properties, definition, taxonomy, societal implications and responsible governance

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    Most applications of Artificial Intelligence (AI) are designed for a confined and specific task. However, there are many scenarios that call for a more general AI, capable of solving a wide array of tasks without being specifically designed for them. The term General Purpose Artificial Intelligence Systems (GPAIS) has been defined to refer to these AI systems. To date, the possibility of an Artificial General Intelligence, powerful enough to perform any intellectual task as if it were human, or even improve it, has remained an aspiration, fiction, and considered a risk for our society. Whilst we might still be far from achieving that, GPAIS is a reality and sitting at the forefront of AI research. This work discusses existing definitions for GPAIS and proposes a new definition that allows for a gradual differentiation among types of GPAIS according to their properties and limitations. We distinguish between closed-world and open-world GPAIS, characterising their degree of autonomy and ability based on several factors such as adaptation to new tasks, competence in domains not intentionally trained for, ability to learn from few data, or proactive acknowledgement of their own limitations. We then propose a taxonomy of approaches to realise GPAIS, describing research trends such as the use of AI techniques to improve another AI (commonly referred to as AI-powered AI) or (single) foundation models. As a prime example, we delve into generative AI (GenAI), aligning them with the terms and concepts presented in the taxonomy. Similarly, we explore the challenges and prospects of multi-modality, which involves fusing various types of data sources to expand the capabilities of GPAIS. Through the proposed definition and taxonomy, our aim is to facilitate research collaboration across different areas that are tackling general purpose tasks, as they share many common aspects. Finally, with the goal of providing a holistic view of GPAIS, we discuss the current state of GPAIS, its prospects, implications for our society, and the need for regulation and governance of GPAIS to ensure their responsible and trustworthy development

    Long-term outcomes (beyond 5 years) of liver transplant recipients - a transatlantic multicentre study

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    The long-term (>5 year) outcomes following liver transplantation (LT) have not been extensively reported. The aim was to evaluate outcomes of LT recipients who have survived the first 5 years. A multicentre retrospective analysis of prospectively collected data from 3 high volume LT centres (Dallas-USA, Birmingham-UK, and Barcelona-Spain) was undertaken. All adult patients, who underwent LT since the inception of the programme to 31 December 2010, and survived at least 5 years since their LT were included. Patient survival was the primary outcome. A total of 3682 patients who survived at least 5 years following LT (long-term survivors) were included. Overall, median age at LT was 52 years (IQR 44–58); 53.1% were males; and 84.6% were Caucasians. 49.4% (n=1820) died during a follow-up period of 36828 person-years (mean follow-up 10 years). 80.2% (n=1460) of all deaths were premature deaths. Age-standardised all-cause mortality as compared to general population was 3 times higher for males and 5 times higher for females. On adjusted analysis, besides older recipients and older donors, predictors of long-term mortality were malignancy, CVD and dialysis. Implementation of strategies such as non-invasive cancer screening, minimising immunosuppression and intensive primary/secondary cardiovascular prevention could further improve survival

    High Step-Up Dual-Switch X-Source DC-DC Converters Integrating Various Capacitor-Winding-Diode Voltage-Double Technology

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    In this article, a new class of high step-up dual-switch X-source dc–dc converters integrating various capacitor-winding-diode voltage-double technology is presented, which are parallel-winding dual-switch X-source dc–dc converters, series-winding dual-switch X-source dc–dc converters, and flipped parallel-winding dual-switch X-source dc–dc converters. According to different winding homonymous end connections, voltage gains and turn ratios of proposed converters have two relations: inversely proportional relations and positive proportional relations. Also, all proposed topologies can produce the higher voltage gain, and own the lower voltage stresses. Operation principles, math derivations, and performance advantages of the proposed converters are analyzed in detail. Finally, the experimental prototype is built to demonstrate the operational feasibility of the proposed converter

    Engineering periodontal tissue interfaces using multiphasic scaffolds and membranes for guided bone and tissue regeneration

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    Periodontal diseases are one of the greatest healthcare burdens worldwide. The periodontal tissue compartment is an anatomical tissue interface formed from the periodontal ligament, gingiva, cementum, and bone. This multifaceted composition makes tissue engineering strategies challenging to develop due to the interface of hard and soft tissues requiring multiphase scaffolds to recreate the native tissue architecture. Multilayer constructs can better mimic tissue interfaces due to the individually tuneable layers. They have different characteristics in each layer, with modulation of mechanical properties, material type, porosity, pore size, morphology, degradation properties, and drug-releasing profile all possible. The greatest challenge of multilayer constructs is to mechanically integrate consecutive layers to avoid delamination, especially when using multiple manufacturing processes. Here, we review the development of multilayer scaffolds that aim to recapitulate native periodontal tissue interfaces in terms of physical, chemical, and biological characteristics. Important properties of multiphasic biodegradable scaffolds are highlighted and summarised, with design requirements, biomaterials, and fabrication methods, as well as post-treatment and drug/growth factor incorporation discussed

    Corporate acquisitions and firm-level uncertainty: Domestic versus cross-border deals

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    This paper investigates how the announcement of acquisitions affect the uncertainty that financial markets perceive about acquiring firms. We use data for publicly-listed firms in the UK between 2004 and 2017 and employ a matching estimator combined with difference-in-differences to address the endogenous selection of firms into acquisitions. While acquisition announcements do not result in a significant change in the volatility of stock returns of acquiring firms across our whole sample, this result hides substantial heterogeneity. Our main finding is that the impact of acquisitions on uncertainty is crucially shaped by a deal's geographic scope—i.e. whether the takeover involves a target in the same country or abroad. Domestic deals reduce the volatility of acquirers' returns by 5% on average one quarter after the announcement, while acquiring a foreign firm increases volatility by a similar magnitude. The heightened volatility resulting from cross-border transactions is primarily driven by acquisitions in industries characterized by high investment irreversibility and foreign markets where barriers to investment are higher. Conversely, the volatility reduction following domestic acquisitions is more pronounced in industries with low irreversibility. Additionally, characteristics of the deal itself, such as the relative size of the acquisition, the payment method, and whether the deal achieves majority control of the target, also play an important role in mediating the effect of acquisitions on volatility


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