Liaoning Normal University

High temperature is a critical environmental factor leading to mass mortality in oyster aquaculture in China. Recent advancements highlight the physiological regulation function of γ-aminobutyric acid (GABA) in the adaptation of environmental stress.

This study examined the physiological responses of the Pacific oyster (Crassostrea gigas) upon high temperature exposure, focusing on the histopathological changes in gill, the GABA concentration, the mRNA expression and activities of apoptosis-related genes. Following 24 h of exposure to seawater at 28 °C, notable histopathological changes, including cellular swelling and vacuolization, along with an increase in TUNEL-positive cells were observed in the oyster gill, compared to the control group maintained at 18 °C. Moreover, there was a significant increase in CgCaspase-3 transcripts, Caspase-3 and Caspase-9 activities in the gills, glutamate decarboxylase CgGAD transcripts in the haemocytes, and GABA concentrations in the haemolymph supernatant. Intervention with GABA markedly ameliorated these responses, including reducing the mRNA expression levels of CgBax, CgBak, CgCaspase-3, and CgCaspase-9, as well as the activities of Caspase-3/9. Furthermore, after the treatment with GABA_A and GABA_B receptor antagonists, the activities and expression levels of Caspase-3 and Caspase-9 significantly up-regulated under hightemperature stress. GABA treatment also significantly diminished the increased Caspase-3 activity by mitochondrial pathway apoptosis inducers.

High temperature induced mitochondrial pathway apoptosis via increased caspase activities. The transcripts of CgGAD in haemocytes and GABA concentration in hemolymph supernatant also increased after high-temperature stress. GABA countered these effects through the activation of GABA_A and GABA_B receptors, reducing both caspase activity and expression of apoptosis-related genes.

The dual-functional metal phosphonate materials with excellent luminescence recognition and proton conduction are a research focus.Herein, two examples of three-dimensional (3D) transition metal phosphonate materials, namely [Cd₂(L¹)₂(Bib)₂(H₂O)]·4·5H₂O (Cd-MOF-1) and [Cd(L²)(Bib)]·3H₂O (Cd-MOF-2), were synthesized by self-assembly with transition metal cadmium ions (Cd^II) under hydrothermal conditions using the isomeric phosphonic acid ligands, 4-carboxyphenylmethylphosphonate Et ester (H₂L¹) and 3-carboxyphenylmethylphosphonate Et ester (H₂L²), and auxiliary ligand 1,4-bis-(1H-imidazol-1-yl)benzene (Bib).Both Cd-MOF-1 and Cd-MOF-2 act as fluorescent probes can achieve rapid, highly sensitive, highly selective and recyclable detection of benzophenone (BP) through fluorescence quenching in the water/ethanol (v: v = 1: 1) solution system.The luminescent recognition mechanisms were thoroughly investigated through experiments and d. functional theory (DFT) calculations, revealing the synergistic effect of static quenching, photo-induced electron transfer (PET), inner filter effect (IFE), and energy competitive absorption.In addition, research on the proton conductivity showed that, at 95 % relative humidity (RH) and 368 K, Cd-MOF-1 and Cd-MOF-2 exhibited proton conductivities of 3.51 x 10^-5 S cm^-1 and 1.21 x 10^-5 S cm^-1, resp.Activation energy (E_a) anal. indicated a Grotthuss (0.37 eV, 333 ∼ 353 K) and Vehicle (1.03 eV, 358 ∼ 368 K) mechanism for Cd-MOF-1, and a Grotthuss mechanism (0.18 eV, 333 ∼ 368 K) for Cd-MOF-2.Detailed structure-activity relationship studies demonstrated that effective active sites and hydrogen-bonding networks enhance the luminescent recognition and proton conductivity performances of the materials, which provided valuable references for the rational design and construction of dual-functional metal phosphonate materials.

β-Ga₂O₃ is a ideal material for fabricating solar-blind UV photoelec. detectors.However, since the intrinsic β-Ga₂O₃ shows n-type conductivity, achieving p-type has been challenging, thereby hindering the development of β-Ga₂O₃ optoelectronic devices.In this study, we fabricated a photoconductive UV photodetector based on single Cu-doped β-Ga₂O₃ microwire.Centimeter-scale β-Ga₂O₃ microwires with varying Cu doping contents were synthesized using chem. vapor deposition method.These microwires had a diameter of approx. 30 nm and a length of up to about 0.8 cm.The p-type conductivity of the Cu-doped β-Ga₂O₃ microwires was confirmed through thermoelec. effect testing.Futhermore, we found that the photodetector composed of microwire with Cu molar percentage of 3.4 % demonstrated the best UV detection performance.The single Cu-doped β-Ga₂O₃ microwire detector exhibited excellent solar-blind photodetector performance, characterized by a high responsivity (57.7 A/W under a bias of 10 V), and external quantum efficiency of 28215 % (under a bias of 10 V), and an I_photo/I_dark ratio of 2.66 x 10⁴ @ 10 V, as well as good stability and repeatability.This work provide a simple and efficient method to preparing p-type β-Ga₂O₃ nano/microstructure and high-performance, stable β-Ga₂O₃-based photodetectors.