Search Results (14,243)

Background: Preoperative anaemia and perioperative transfusion are associated with adverse outcomes after cardiac surgery with cardiopulmonary bypass (CPB). Coronavirus disease 2019 (COVID-19) may induce persistent haematological and endothelial alterations. Whether previous infection modifies the relationship between haemoglobin and outcomes is unclear. This study evaluated whether previous COVID-19 infection modified the association between preoperative haemoglobin concentration and perioperative transfusion burden after cardiac surgery with CPB. Early postoperative complications were analysed as predefined secondary outcomes. Methods: This study represents a secondary analysis of a prospective observational cohort of adult patients undergoing elective on-pump cardiac surgery between 1 August 2022 and 30 October 2023. Patients were categorised according to previous COVID-19 infection. Surgery was performed at least seven weeks after infection. The primary outcome was perioperative transfusion burden, defined as the total number of blood products administered from the intraoperative period until hospital discharge. An interaction term between previous COVID-19 and preoperative haemoglobin was included in multivariable linear regression. Results: A total of 280 patients were included, of whom 101 (36.1%) had a previous COVID-19 infection. Preoperative haemoglobin was comparable between patients with and without a previous COVID-19 infection (13.4 [12.4–14.8] vs. 13.8 [12.2–14.6] g/dL; p = 0.472). No significant differences in early postoperative complications, transfusion rates, or transfusion burden were observed according to previous COVID-19 infection. The COVID-19 × haemoglobin interaction was not statistically significant in the adjusted model (B = 0.002, 95% CI −0.081 to 0.085; p = 0.958). Lower preoperative haemoglobin, lower baseline platelet count, longer CPB duration, and CKD were independently associated with greater transfusion burden. In an exploratory multivariable analysis, preoperative anaemia remained associated with postoperative AKI after adjustment for relevant covariates (adjusted OR 5.80, 95% CI 2.23–15.06; p < 0.001). Conclusions: No statistically significant interaction between previous COVID-19 and preoperative haemoglobin was demonstrated for perioperative transfusion burden. Lower preoperative haemoglobin was independently associated with greater transfusion burden, while preoperative anaemia remained associated with postoperative AKI after multivariable adjustment in an exploratory analysis. These findings support systematic preoperative anaemia screening and Patient Blood Management in cardiac surgery. Full article

Background/Objectives: Antimicrobial peptides (AMPs) are considered alternatives to classical antibiotics due to limited resistance development in bacteria. However, bacteria can develop resistance to AMPs through evolutionary adaptation, including oligosaccharide modifications and multidrug efflux pumps. Further research is needed to elucidate the defense mechanisms employed against AMPs to address the emerging resistance problem. Pexiganan is a cationic peptide with effective broad-spectrum antimicrobial activity. The aim of this study is to elucidate the genomic and transcriptomic basis of E. coli’s evolutionary adaptation to pexiganan. Methods: The E. coli ATCC BAA-2523 strain became resistant to pexiganan via evolutionary adaptation methodologies. Whole-genome and transcriptome analyses of resistant and susceptible populations were conducted using Nanopore sequencing and Illumina RNA sequencing, respectively. Results: Resistance development became particularly evident after 15 µg/mL, and the bacteria demonstrated the ability to grow even at high doses (up to 1000 µg/mL). Increases in expression levels of classical ARGs such as emrB, acrF, OXA, sul2, and dfrA14 in the pexiganan-resistant strain indicate that bacteria have the potential for broad-spectrum resistance to other antibiotics alongside pexiganan. Missense mutations have been identified in the phosphatidylserine synthase and cardiolipin synthase genes, which are involved in membrane biosynthesis. Increased expression was observed in the membrane-bound lytic murein transglucosylase (mltF), the murein hydrolase activator (EnvC), and the Antigen 43 (Ag43) gene. Conclusions: Pexiganan may not only target the cell membrane but also trigger the bacterium’s overall transcriptional response and cross-resistance and MDR systems. Upregulation of multidrug efflux pumps, lytic murein transglucosylase, the murein hydrolase activator and the Antigen 43 gene might be associated with resistance. In addition, the missense mutation was detected in the membrane biosynthesis genes pssA and clsB. In vivo infection models, targeted functional genomics, and comprehensive phenotypic cross-resistance testing will be required to validate our results. Full article

A fluid–structure interaction (FSI) model of the guide vane and runner of a pump-turbine was developed by applying unsteady hydraulic pressure loads obtained from CFD simulations to the structural surfaces. The deformation behavior, stress distribution, and modal response of the stay vane, movable guide vane, and runner were investigated under different operating conditions. The maximum deformation of the stay vane occurs at the middle section of the blade leading edge, whereas the maximum deformation of the movable guide vane is located near the trailing edge. The maximum deformation of the runner occurs at the junction between the blade leading edge and the band. Modal analysis shows that the fourth natural frequency of the movable guide vane approaches the eighth-order guide-vane passing frequency, while the sixth natural frequency of the runner approaches the fourth-order runner blade-passing frequency, suggesting a potential risk of vibration amplification. Full article

The use of non-certified commercial electronics for cryogenic applications may be attractive due to their reduced cost and high availability, but they also carry risks related to reliability, performance, and thermal compatibility. The decision to use commercial components that are not certified for cryogenics instead of components specifically designed for such applications must be carefully weighed based on specific project needs and risk tolerances. This work presents the characterisation of a Low-Noise Amplifier (LNA) at cryogenic temperatures for use in astronomical instrumentation applications with a microwave kinetic inductance detector (MKID) readout system. The cooling system comprises a cryostat, a cold head operating in a closed-cycle helium refrigeration system based on the Gifford–McMahon principle, a compressor, connectors, cables, a vacuum pump, pressure and temperature sensors, and a temperature control system. The circuit was characterised over the temperature range of 295.4 K to 78.3 K. Full article

Coronary artery bypass grafting via median sternotomy carries considerable morbidity, and minimally invasive robotic approaches have been increasingly performed for surgical revascularization of coronary arteries. We report our institutional experience in robotic-assisted minimally invasive coronary revascularization in a broad patient population with complex multivessel disease. We retrospectively reviewed robotic-assisted minimally invasive direct coronary artery bypass (RA-MIDCAB) procedures performed at our center between January 2022 and June 2026. Patient demographics, additional procedures and in-hospital outcomes were recorded. A total of 242 patients were included (mean age 63.4 ± 9.7 years; 31 (12.8%) female). Single-vessel bypass was performed in 25 (10.3%) patients; 212 (87.6%) patients underwent an operation on the arrested heart (mean cross-clamp time 66.9 ± 21.7 min) and 15 (6.2%) received an off-pump operation (mean CPB time in on-pump patients 155.7 ± 46.0 min). Full arterial revascularization was achieved in 42 (17.4%) patients; a bilateral internal mammary artery configuration was used in 9 (3.7%) patients. Coronary endarterectomy was performed in 16 (6.6%) patients and concomitant left atrial appendage (LAA) occlusion was performed in three (1.2%) patients. Epiaortic ultrasonography-guided clamp placement was performed in 27 (11.2%) patients with ascending-aortic plaque. In-hospital mortality occurred in two (0.8%) patients; no patient sustained a major neurological deficit, and the transfusion rate was 9.9%. Mean ventilation time was 4.0 (3.0–6.0) hours and mean intensive care unit stay was 22.6 ± 11.2 h. With careful planning and accumulated experience, the indications for robotic-assisted minimally invasive revascularization can be extended to include patients who require full-arterial revascularization, have ascending aortic plaques, complex coronary disease requiring endarterectomy, or atrial fibrillation where concomitant left atrial appendage occlusion is indicated. Full article

Loss-of-excitation faults are a common fault form of pumped storage units that can threaten both unit safety and grid stability. However, the traditional loss-of-excitation protection based on the impedance principle may exhibit delayed operation or even fail to operate in the case of partial loss of excitation or loss of excitation under light-load conditions, and there is a risk of maloperation in the case of system oscillation. Therefore, this paper analyzes the differences in the characteristics of electrical quantities such as voltage, current, active power, reactive power and power angle during the loss of excitation and system oscillation of a pumped storage unit, and proposes a loss-of-excitation index criterion based on the magnitudes and polarities of variations in terminal voltage, reactive power, and power angle, which constitutes a new method of pumped storage unit loss of excitation fault protection. The simulation results show that compared with the traditional impedance principle loss-of-excitation protection, the proposed method reduces the operating time by 58.6–90.0%. It can reliably and quickly detect the loss-of-excitation fault of pumped storage units under various operating conditions, and shows good anti-maloperation ability for non-loss-of-excitation faults and system oscillation. In addition, the proposed protection method can still maintain reliable operation under the condition of noise interference with a signal-to-noise ratio of 20 dB or communication delay of 0.2 s, which verifies its strong engineering practicability and anti-interference ability. Full article

Myocardial infarction (MI) is characterized by sudden cardiomyocyte death due to impaired blood supply and remains a leading cause of mortality despite advances in management. Aloe vera, a plant rich in over 75 bioactive compounds, including vitamins, minerals, polysaccharides, and anthraquinones, has been widely used in traditional medicine and modern healthcare. Increasing evidence supports its cardioprotective potential through multiple mechanisms. Aloe vera and its derivatives have demonstrated antioxidative, anti-apoptotic, anti-inflammatory, antimicrobial, immunomodulatory, and vasodilatory effects relevant to MI pathophysiology. Compounds such as aloe-emodin, emodin, aloin, barbaloin, and selenium-enriched polysaccharides have been shown to modulate pathways including Nrf2/HO-1, TGF-β/SMAD, ERK, ferroptosis inhibition, ionic pump activity, and microRNA regulation. These molecular effects translate into reductions in oxidative damage, apoptotic signaling, inflammatory cytokine release, calcium imbalance, and creatine kinase/LDH leakage, while preserving myocardial structure and function in preclinical models. Collectively, preclinical studies suggest the potential cardioprotective effects of Aloe vera-derived preparations and compounds; however, robust clinical evidence in myocardial infarction is lacking, and their therapeutic relevance remains uncertain. Full article

To address the contradiction between high resolution and structural complexity in traditional laser self-mixing measurement systems, the co-axial dual-wavelength solid-state laser self-mixing technology was proposed and studied. An LD pumped the Nd:YVO4 crystal and doubled the frequency to generate two wavelengths laser at 1064 nm and 532 nm, and a co-axial dual-wavelength laser self-mixing measurement system was constructed. A 90° phase difference between the two wavelengths was produced by adjusting the angle of incidence of the parallel glass plate. As a result, a set of orthogonal signals was built to distinguish the direction of the displacement for the target. The experiments showed that the measuring system can adapt to different vibration waveforms and that the frequency measurement upper limit can be reached at 7 kHz. The system exhibited high precision in displacement measurement, with an RMS displacement noise of 8.64 nm and a cumulative error of 33.66 nm at a peak-to-peak amplitude of 5000 nm, along with a short-term resolution better than 2 nm. Full article

This article presents a technical and economic analysis of a photovoltaic system operating in conjunction with a heat pump in a single-family home. The aim of this study was to compare the cost-effectiveness of two prosumer billing systems currently in use in Poland, net metering and net billing, implemented in accordance with the provisions of the Renewable Energy Sources (RES) Act and the Energy Law and to assess the effectiveness of a proprietary algorithm for managing surplus electricity produced by the photovoltaic system. The energy performance of the facility was determined using ArCADia Termo 11.1 software, while energy and economic calculations were performed using Microsoft Excel 365 and a developed heat pump control algorithm. The algorithm is based on an analysis of the building’s energy balance with a 15 min resolution and utilizes data on outdoor temperature, energy production from the PV system, building heat loss, heat pump operating parameters, and energy self-consumption. Its goal was to maximize the use of energy produced for the building’s own needs by appropriately controlling the heat pump and storing surplus energy as heat stored in domestic hot-water tanks. The annual electricity consumption of the analyzed building was 6902.18 kWh, of which 3724.13 kWh was for heating and domestic hot water provided by the heat pump. The algorithm reduced grid energy consumption by approximately 900 kWh per year and achieved a self-consumption level of 12.73 (%). Full article

During high-speed multi-joint coordination, the nonlinear joint-to-cylinder mapping may increase the velocity and jerk peaks of the hydraulic cylinders, while simultaneous multi-cylinder motion may cause flow-peak superposition and increase the risk of exceeding the pump-flow limit. Addressing the limitations of traditional joint-space trajectory planning, which struggles to balance actuator-space smoothness, nonlinear inverse kinematics robustness, and multi-cylinder total-flow constraints, this paper proposes a multi-objective trajectory-planning method in the hydraulic-cylinder actuator space. First, a kinematic model is constructed based on the modified Denavit–Hartenberg method and hydraulic-cylinder closed-loop cosine mapping to evaluate effective moment arms and transmission sensitivity. Subsequently, a method combining Monte Carlo global search and Levenberg–Marquardt local iteration is adopted to solve inverse kinematics without explicitly computing the Moore–Penrose pseudoinverse of the Jacobian. On this basis, analytic quintic splines incorporating asymmetric perturbation terms are constructed, and a non-dominated sorting genetic algorithm II bi-objective optimization model for minimizing the motion time and the maximum absolute jerk in the actuator space is established, incorporating the total-flow hard constraint. Simulation results demonstrate that the motion time of the compromise solution is 7.71 s, the maximum absolute jerk in the actuator space is 22.94 mm/s³, and the total flow throughout the process is lower than 105 L/min. This method keeps the planned total-flow demand within the pump-flow capacity and reduces the risk that the planned actuator speeds cannot be maintained because of insufficient flow supply, providing a planning basis for the stable operation of heavy-duty hydraulic demolition robots. Full article

Reverse osmosis (RO) desalination is a major technology for freshwater production in arid regions, but its energy demand becomes more challenging when the system is supplied by variable renewable energy. This study presents an offline digital-twin-assisted decision-support framework for dynamic RO under Kuwait solar-availability conditions. Within this framework, the predictive models are driven primarily by the dynamic RO process variables, while NASA Prediction Of Worldwide Energy Resources (POWER) data provide the Kuwait solar-availability context, and the PV power margin serves as a scenario-level energy indicator. The purpose is to predict instantaneous permeate flow rate, estimate specific energy consumption, and identify energy-efficient operating conditions using machine learning. Kuwait City was used as the solar case-study location. Hourly solar and meteorological data were obtained from NASA POWER, while dynamic RO membrane data were obtained from the open experimental wave desalination dataset published by the National Renewable Energy Laboratory (NREL) through Data.gov and the Marine and Hydrokinetic Data Repository. The RO dataset includes steady-state, ramp, sinusoidal, and Wave Energy Converter SIMulator (WEC-Sim) pressure/flow experiments. The process-flow image used in the system description was also taken from the same NREL dataset and is cited in the figure caption. The raw RO files were cleaned, harmonized, and transformed into a process-informed modeling dataset. Derived features included pressure rate, recovery ratio, salt rejection, estimated pump power, specific energy consumption (SEC), PV power margin, and rolling pressure/flow features. Three supervised regression models were tested: Gradient Boosting, Random Forest, and XGBoost. A representative subset of 60,000 records was used to preserve the main experimental conditions while reducing redundancy in the densely sampled sequential data. Results show that permeate flow rate can be predicted with high accuracy using Gradient Boosting (R² = 0.981; RMSE = 0.161 L/min). The moderate energy prediction performance yielded an R² of 0.654 and RMSE of 7.570 kWh/m³ for Random Forest. The accuracy of permeate conductivity predictions was lower (R² = 0.257; RMSE = 245.44 µS/cm) because membrane and feed characterizing parameters should be included for an adequate water quality control. The proposed approach is best suited as an offline decision-support framework for dynamic RO process analysis. Full article

The present work presents a new synthetic jet piezoelectric pump designed to address the airflow delivery needs arising from the increasing power density of high-performance microelectronics. Traditional miniaturized cooling techniques suffer from low efficiency, bulky size, and high cost, while microfluidic cooling has emerged as a vital chip thermal management method with outstanding miniature heat removal capacity. We systematically designed the vibration mode and pump structure, adopting the sixth-order resonant frequency as the operating frequency. A dual resonant layer with stiffness-guided fixed boundaries was employed to enhance vibration efficiency and energy conversion, together with an optimized flow channel layout and parametric design. Experiments conducted under 35 V square-wave excitation demonstrate that the 20 mm × 20 mm × 2.5 mm pump delivers a flow rate of 1.6 L/min and a back pressure of 2.7 kPa. This work provides a feasible technical route for large-scale airflow delivery applications of synthetic jet piezoelectric pumps, with potential for thermal management in microelectronic devices, while balancing excellent performance and low manufacturing cost. Full article

To address the limited cooling range of ventilation in deep, high-temperature development headings and the lack of coordinated design between coil-based cooling and the ventilation system, this study proposes a coupled “twin-forcing–coil” cooling scheme. Building on conventional overlap (forcing–exhausting) ventilation, a rear-mounted second forcing duct is added to the conventional overlap (force–exhaust combined) auxiliary ventilation system, forming a dual-duct forcing, single-exhausting configuration—hereafter termed the “twin-forcing–single-exhausting” (TFSE) system—that provides a booster (relay) air supply to mitigate the along-path attenuation of cooling capacity and the short-circuiting of cold air; an in situ heat-exchange coil wall further provides supplementary cooling where ventilation-based temperature control weakens. Using a development heading at the 790 m level of a metal mine in Yunnan as the engineering background, a three-dimensional numerical model coupling the roadway, ventilation system, and coil wall was established and validated against nine field monitoring points, showing average relative errors of approximately 1% for temperature and 2–3% for humidity, comparable to the measurement uncertainty of the field instrumentation. Because the numerical model does not account for evaporative and condensation phase-change processes, two supplementary development headings with standing water at the face were used for validation; results showed that model error increases with water accumulation and heading length, indicating the model’s applicability is limited to conditions with intact surrounding rock and minimal seepage. Six operating cases were designed with duct placement and coil spacing as variables. Results show that single-duct ventilation cooling decays markedly beyond 30 m from the face, whereas twin-forcing booster (relay) air supply effectively extends the cooling range, reducing the 30–70 m section temperature by 2.7–2.9 K; the second duct should be positioned where the first duct’s cooling capacity begins to attenuate but is not yet depleted. Based on only two spacing configurations tested (10 m and 15 m), coil-staggered spacing showed limited effect on cooling performance under the field conditions examined; this preliminary finding requires validation across a broader range of spacings. Among the chilled-water conditions tested, an inlet temperature of 280.65 K and a flow velocity of 0.5 m/s offered a reasonable trade-off between cooling uniformity and economic efficiency. Under the boundary conditions and equipment parameters of this case, energy consumption estimates further indicate that the cooling effect per unit electricity consumption of twin-forcing ventilation is roughly 6–8 times that of coil-based cooling, primarily due to pumping losses over the ~240 m chilled-water delivery distance. This energy penalty indicates that coil-based cooling is better suited as a localized, short-distance supplementary measure rather than as a means of extending the cooling range over long distances. Full article

The global emergence of multidrug-resistant fungal pathogens, including Candida auris, Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans, and Pneumocystis jirovecii, poses a growing threat to public health, particularly among immunocompromised individuals. The limited number of available antifungal drug classes and the rapid evolution of resistance mechanisms, including target-site mutations, efflux pump activation, biofilm formation, metabolic adaptation, and stress-response signaling, have substantially reduced treatment efficacy. This review provides a comprehensive overview of current antifungal therapies, their limitations, and emerging molecular targets for next-generation antifungal drug discovery. We highlight promising targets involved in fungal cell wall biosynthesis, membrane integrity, mitochondrial metabolism, virulence regulation, and host–pathogen interactions, emphasizing their interconnected roles within adaptive resistance networks. Attention is given to small-molecule isothiazolone-based inhibitors, including phosphoglucomutase-targeting compounds, as novel candidates capable of disrupting multiple fungal survival pathways. We further discuss advances in combination therapies, anti-virulence approaches, nanotechnology-based delivery systems, and artificial intelligence-driven drug discovery pipelines that integrate multi-omics data, structural modeling, molecular docking, and virtual screening to accelerate therapeutic development. These advances support a transition from conventional single-target strategies toward systems-level, precision-guided antifungal therapies, providing a framework for overcoming multidrug resistance and improving clinical outcomes in invasive fungal infections. Full article

Pump-turbines often experience performance deterioration under high-load conditions beyond their best efficiency point, while the underlying flow mechanisms remain insufficiently understood. In this study, we investigate the relationship between internal flow structures and energy performance in a pump-turbine operating at a rated head of 202 m over a range of guide vane openings. Energy losses are evaluated using an average kinetic energy-based method and compared with an entropy production approach. A threshold-independent rigid vorticity method is adopted for vortex identification, and a streamline-based coordinate system is introduced for spatial quantification of energy loss and blade loading. The results show that hydraulic losses are mainly concentrated in the draft tube (66–75%) and runner (25–30%) under high-load conditions. A coupled vortex system formed by separation vortices and horseshoe vortices governs localized dissipation in the runner. In the draft tube, a columnar vortex rope generates strong shear layers that dominate energy loss in the cone and elbow regions. At high flow rates, negative incidence induces pressure-side separation, forming negative torque regions that reduce net runner torque and lead to output power deterioration. These findings highlight the dominant role of coupled vortex structures and pressure redistribution in performance degradation under high-load operation. Full article