Recent advances in metallic transition metal dichalcogenides as electrocatalysts for hydrogen evolution reaction

Layered metallic transition metal dichalcogenides (MTMDs) exhibit distinctive electrical and catalytic properties to drive basal plane activity, and, therefore, they have emerged as promising alternative electrocatalysts for sustainable hydrogen evolution reactions (HERs). A key challenge for realizing-MTMDs-based electrocatalysts is the controllable and scalable synthesis of high-quality MTMDs and the development of engineering strategies that allow tuning their electronic structures. However, the lack of a method for the direct synthesis of MTMDs retaining the structural stability limits optimizing the structural design for the next generation of robust electrocatalysts. In this review, we highlight recent advances in the synthesis of MTMDs comprising groups VB and VIB and various routes for structural engineering to enhance the HER catalytic performance. Furthermore, we provide insight into the potential future directions and the development of MTMDs with high durability as electrocatalysts to generate green hydrogen through water-splitting technology

Treatment of Discoid Lupus Erythematosus in a Dog with Human Intravenous Immunoglobulin

Background: Discoid lupus erythematosus (DLE) is a common canine autoimmune skin disease, in which systemic manifestations are absent. Skin Lesions are usually present on the nasal planum, and characterised by erythema, depigmentation, erosion, ulceration, and crusting. The diagnosis is based on histopathological results, which should demonstrate lymphoplasmacytic lichenoid-interface dermatitis. Human intravenous immunoglobulin (hIVIg) has been used in veterinary medicine to treat cutaneous diseases including erythema multiforme, PF, and severe adverse cutaneous drug reactions. In human medicine, it has been effective to treat DLE. This report firstly describes the clinical response to hIVIg in a dog with DLE resistant to common immunosuppressive drugs.Case: A 5-year-old, intact female Shih Tzu presented with a 1-month history of slowly progressive black crusting on the nasal planum, chin, and claw. Based on the results of a dermatologic examination, superficial pyoderma was diagnosed. The skin lesions did not improve during and after anti-infective treatment. After removing the crusts, a skin biopsy was obtained from the muzzle. Histopathology of lesional skin biopsy specimens revealed lymphoplasmacytic interface dermatitis at the dermoepidermal junction. Microscopic examination also revealed vacuolar changes and pigmentary incontinence of the basal layer as a lichenoid tissue reaction. No mites or fungi were detected on the skin section. The absence of acantholytic cells excluded pemphigus foliaceus, which is also characterised by the lesions of the nasal planum. Based on the distribution of the lesions, histopathology and exclusion of other dermatoses, the dog was diagnosed with DLE. The skin lesions temporarily improved after treatment with prednisolone (2 mg/kg PO q12h). However, after tapering the dose of prednisolone, new black crusts developed on the nasal planum and claw. Although the dog was successively treated with other immunosuppressive drugs, including azathioprine, cyclosporin with dexamethasone, and mycophenolate mofetil, black crusts still remained. Due to the low efficacy of these immunosuppressive drugs, hIVIg was administered at 0.5 g/kg once daily for 4 days, for a total dose of 2 g/kg. During hIVIg administration, the crusted lesions gradually improved. After the hIVIg administration, the dog was treated with prednisolone (1 mg/kg PO q12h). The lesions were almost in complete remission at 21 days after an additional application of prednisolone. The skin lesions did not recur, and the treatment was eventually discontinued after 6 weeks of additional prednisolone application.Discussion: The standard treatment of canine DLE includes glucocorticoids, and second-line immunosuppressive drugs, such as azathioprine and cyclosporine, are usually added in cases resistant to steroids. This case suggests that hIVIg may be beneficial as an adjunctive treatment option for canine DLE, especially when the application of standard immunosuppressive drugs is limited due to adverse effects or low efficacy. There is evidence from several studies that the steroid-sparing effect of hIVIg is significant in human patients. In the current case, the effective dose of prednisolone was reduced to 2 mg/kg/day after hIVIg administration, and prednisolone therapy was finally discontinued completely. The hIVIg appears to lower the daily steroid dose requirement in this dog. Keywords: autoimmune skin disease, discoid lupus erythematosus, canine dermatology, immunosuppressive drug, human intravenous immunoglobulin

Kdm3b haploinsufficiency impairs the consolidation of cerebellum-dependent motor memory in mice

Histone modifications are a key mechanism underlying the epigenetic regulation of gene expression, which is critically involved in the consolidation of multiple forms of memory. However, the roles of histone modifications in cerebellum-dependent motor learning and memory are not well understood. To test whether changes in histone methylation are involved in cerebellar learning, we used heterozygous Kdm3b knockout (Kdm3b+/−) mice, which show reduced lysine 9 on histone 3 (H3K9) demethylase activity. H3K9 di-methylation is significantly increased selectively in the granule cell layer of the cerebellum of Kdm3b+/− mice. In the cerebellum-dependent optokinetic response (OKR) learning, Kdm3b+/− mice show deficits in memory consolidation, whereas they are normal in basal oculomotor performance and OKR acquisition. In addition, RNA-seq analyses revealed that the expression levels of several plasticity-related genes were altered in the mutant cerebellum. Our study suggests that active regulation of histone methylation is critical for the consolidation of cerebellar motor memory.This work was supported by grants to S.B.S. and Y.-S.L. (NRF2019R1A4A2001609), Y.-S.L. (NRF-2017M3C7A1026959), and S.J.K. (NRF2018R1A5A2025964) from the National Research Foundation of Korea

Economic and environmental analysis of the optimum design for the integrated system with air source heat pump and PVT

Recently, research on a hybrid heat pump system that combines photovoltaic-thermal (PVT) and air source heat pump (ASHP) technologies has been actively conducted. However, there is a lack of research on validating the integrated ASHP-PVT system model based on real buildings and designing the integrated system optimally. In this study, a prediction model was constucted using dynamic simulation, validated based on a real building. The integrated system was optimally designed for real application, and a comprehensive performance evaluation was conducted using the conventional model. The payback period of the optimum model was 9.42 years, 3 years shorter than the conventional model. The optimum model showed an increase in power consumption by approximately 4% compared to the conventional model. However, power consumption was still observed to decrease by up to 43% when compared to a model that does not utilize PVT. This study shows that the proposed system promotes decarbonization of the building sector and provides considerable economic benefits through optimum design implementation

Performance Analysis of Integrated Photovoltaic-Thermal and Air Source Heat Pump System through Energy Simulation

The concept of zero energy buildings (ZEBs) has recently been actively introduced in the building sector, globally, to reduce energy consumption and carbon emissions. For the implementation of ZEBs, renewable energy systems, such as solar collectors, photovoltaic (PV) systems, and ground source heat pump (GSHP) systems, have been used. The system performance of solar collectors and PV systems are dependent on the weather conditions. A GSHP system requires a large area for boring machines and mud pump machines. Therefore, inhabitants of an existing small-scale buildings hesitate to introduce GSHP systems due to the difficulties in installation and limited construction area. This study proposes an integrate photovoltaic-thermal (PVT) and air source heat pump (ASHP) system for realizing ZEB in an existing small-scale building. In order to evaluate the applicability of the integrated PVT-ASHP system, a dynamic simulation model that combines the PVT-ASHP system model and the building load model based on actual building conditions was constructed. The heating and cooling performances of the system for one year were analyzed using the dynamic simulation model. As the simulation analysis results, the average coefficient of performance (COP) for heating season was 5.3, and the average COP for cooling season was 16.3., respectively. From April to June, the electrical produced by the PVT module was higher than the power consumption of the system and could realize ZEB

Performance improvement of air-source heat pump via optimum control based on artificial neural network

The use of air source heat pump (ASHP) systems is an economically viable strategy for building decarbonization. However, the ASHP energy performance deteriorates under severe conditions around a building. Researchers have conducted studies for optimal compressor control to overcome these limitations. Despite these efforts, users can seldom perform the optimal regulation of heat pump systems because manufacturers are reluctant to relinquish control to them. Therefore, we developed an artificial neural network (ANN)-based optimum control logic (OCL) system such that users can directly control and optimize heat pump systems without a compressor. The developed ANN-based OCL controls the secondary-side working fluid of the heat pump considering general building conditions, and its practical applicability has been verified using dynamic simulation. The improvement in the energy performance of the optimum models with respect to the conventional models was: 1.52% and 3.58% for the cooling and heating system COP, respectively, and 0.76% and 0.81% for the heat pump COP. These results demonstrate the potential for reduction in the carbon footprint of a building while maintaining comfort by enabling the energy-efficient operation and stable load response of the heating and cooling system

Economic and performance analysis of ground source heat pump system for high-rise residential buildings considering practical applications

Ground source heat pump (GSHP) systems are being applied in various buildings to achieve carbon neutrality and zero energy building. Large-scale residential buildings have seen limited use of GSHP systems due to the absence of design guidelines and established operation methods. While design guides for general buildings are available from associations or institutes, there is a scarcity of designs and operation guides that consider dynamic simulations with occupant conditions and detailed load conditions. Generally, it is crucial for the economic analysis to optimally design suitable system capacity and accurately predict the performance. Therefore, in this study, the dynamic energy simulation model was constructed by considering the condition of the occupants and system operation and quantitively analyzed economic feasibility and system performance. Furthermore, the sensitive analysis based on the practical range of operation was conducted for comparison with conventional systems, district heating (DH) and electric heat pump (EHP) system. The heat pump's performance improved by up to 12.6% based on GSHP system design factors. Although the initial investment cost of the GSHP system was 51.5–84.7% higher than DH and EHP systems, its annual operating cost was 20.8–33.1% lower. The ground source heat exchanger had the most significant impact on performance, while the thermal storage tank's capacity had the largest impact on annual operating costs, aligning with previous research findings. In terms of carbon emissions, the annual CO2 emissions of the GSHP system were 49.1% lower than those of the existing system. The study highlights that GSHP systems can achieve high performance, economic efficiency, and low CO2 emissions based on the design approach. Additionally, the study provides valuable insights into GSHP system design, offers quantitative feasibility data, and compares them to traditional heating and cooling systems, taking practical cost considerations into account

Feasibility study on energy harvesting with thermoelectric generators in a photovoltaic-ground source heat pump system

Thermoelectric generators (TEGs) harness temperature differences to produce electricity and hold promise for diverse industrial applications. However, their limited conversion efficiency casts doubt on their role in achieving energy independence. This study introduces an advanced technique that exploits temperature gradients in water pipes, utilizing supplementary TEGs to augment power generation. This method maintains a stable temperature gradient for TEG operation. Additionally, TEG power output can be efficiently modulated via flow control. In the feasibility evaluation for residential settings, the temperature fluctuations across each system unit were analyzed. In the active system, the chosen sites for TEG integration were units equipped to manage heat transfer using working fluids. The inlet and outlet temperatures were calculated for photovoltaic-thermal (PVT) systems, ground heat exchangers (GHEs), and heat storage tanks (HSTs). The electricity produced by the TEGs was benchmarked against their conversion efficiency, zT. The results indicated that the TEGs yielded 10.95 kWh of electricity when systematically implemented in each unit. To realize a zero-energy building, an area of 64.5 m2 per unit is necessitated for TEG deployment, given a zT value of 1

Photovoltaic–thermal advanced technology for real applications: Review and case study

This study analyzes research trends on photovoltaic–thermal (PVT) systems used in buildings. The applications of PVT systems are also classified into system design, material and fluid types, and operating methods. Although many studies proposed new types of PVT systems and applications to improve system performance, there are few reports on the design and operating methods for the system, which consists of the PVT system and hot water storage tank in real-scale buildings. Therefore, our research team conducted a quantitative evaluation of a small household with a PVT system and hot water storage tank installed, according to design factors. The results of the parametric study showed that electricity production was more sensitive to changes in system capacity than those in heat production. By contrast, the change in heat production was dominant in response to the change in the installation angle and load profile of domestic hot water. Through energy simulation, it was found that the PVT system could provide 95% of the annual thermal energy for the domestic hot water consumption of the target buildings