Gata4 is required for Testicular Development

Sex differentiation occurs at embryonic day 10.5 (E10.5) in the mouse. In the XY mouse embryos, appearance of testis cords at E11.5 marks the onset of testis formation. The primary testis cords subsequently undergo further development characterized by rapid and extensive branching, elongation and coiling, resulting in hundreds of thousands of secondary or tertiary testis cords, which will develop into future seminiferous tubules during postnatal testicular development. Here we report that inactivation of Gata4 at E12.5 in Sertoli cells does not affect testis cord formation, but blocks its further development leading to testicular dysgenesis and male infertility in adult mice. Our data demonstrate that Gata4 is required for normal testis cord branching, elongation during embryonic development, and untimely the normal number of seminiferous tubule precursors available for the postnatal testicular development. Disruption of Gata4 or its target genes involved in testis cord development will significantly affect the number of future seminiferous tubules, the size of the testis and fertility

Prototypical Contrastive Learning-based CLIP Fine-tuning for Object Re-identification

This work aims to adapt large-scale pre-trained vision-language models, such as contrastive language-image pretraining (CLIP), to enhance the performance of object reidentification (Re-ID) across various supervision settings. Although prompt learning has enabled a recent work named CLIP-ReID to achieve promising performance, the underlying mechanisms and the necessity of prompt learning remain unclear due to the absence of semantic labels in ReID tasks. In this work, we first analyze the role prompt learning in CLIP-ReID and identify its limitations. Based on our investigations, we propose a simple yet effective approach to adapt CLIP for supervised object Re-ID. Our approach directly fine-tunes the image encoder of CLIP using a prototypical contrastive learning (PCL) loss, eliminating the need for prompt learning. Experimental results on both person and vehicle Re-ID datasets demonstrate the competitiveness of our method compared to CLIP-ReID. Furthermore, we extend our PCL-based CLIP fine-tuning approach to unsupervised scenarios, where we achieve state-of-the art performance

Novel Vapor Compression Cycles with High Energy Efficiency Using Natural Refrigerants for Three Kinds of Appliances

Natural refrigerants are eco-friendly substitutes for HCFCs and HFCs in vapor compression cycles, such as refrigeration or heat pump cycles. In this paper, three appliance systems are analyzed based on refrigerants characteristics for performance improvement, and novel and practical cycles are proposed and briefly analyzed. Dual-evaporator (DE) cycle for refrigerator can reduce the irreversible thermodynamic loss in one-stage cycle. Rotary compressors which have advantages in efficiency and dynamic balance capability are highly suitable to DE cycles. The improvement of theoretical refrigeration coefficient for DE cycle is up to 24.4% comparing with conventional one-stage cycle under refrigerator condition. Vapor injection heat pump (VIHP) cycle can efficiently improve the cycle performance especially under low ambient temperature. In the VIHP using R290 as refrigerant, the discharge temperature of compressor is usually not high enough for proper solubility of refrigerant in lubricant oil. Two techniques are applied to raise the discharge temperature, which brings higher performance and lubricating property to the compressor, and also brings the promotion to the cycle. The maximum improvements of theoretical heating coefficient and volumetric heating capacity are up to 17.8% and 40.7% respectively when evaporation temperature is -30℃. Heat pump cycle is suitable for electric vehicles because of its high coefficient of performance (COP) and heating capacity. In the heat pump cycle using CO2, combining with the fresh air heating progress in vehicle and wet compression, a particular cycle is proposed with much higher cycle performances. The COP and volumetric heating capacity can be at least 39.5% higher than that of conventional heat pump cycle when evaporation temperature is -30℃. And wet compression makes further improvements