AZ31 magnesium alloy strips have been cold-rolled to thickness reduction of 33% and followed by electropulse treatment (EPT) with different current parameters for 7s and furnace annealing for ...comparison. The results indicate that recrystallization is drastically accelerated by EPT and continuous recrystallization induced by EPT is strongly dependent on the current. Deformed coarse-grain boundaries together with extension twins (ET) bands provide sources for nucleation and are gradually consumed by recrystallization. A double peak texture was generated after recrystallization, which is associated with the promoted non-basal nucleation and the non-basal dislocations activities.
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Exploring the effects of environmental factors and plant physiological processes on plant nutrient stoichiometry is of great significance to understanding how wetland vegetation distributes and ...maintains function. However, we have a limited understanding of how the combination of plant communities and seasonality with soil physicochemical properties affects nutrient stoichiometry in wetland plants. In this study, we examined these factors in Carex thunbergii and soil across four types of plant communities dominant in the riparian zone of Shengjin Lake during the non−flooding periods of December 2020 and March 2021. In winter, the total foliar C, N, and P concentrations decreased along with an increase in plant coverage, which did not differ in spring. The C, N, C: P, and N: P of foliage significantly increased over the season, while soil C, N, C: P, and N: P significantly decreased over the season. Both in winter and spring, soil C and soil N decreased along with the increase of plant coverage. Our results suggest that both plant community and soil physicochemical properties have a significant influence on plant nutrient stoichiometry. This study improves our understanding of the seasonal dynamics of plant nutrients under different communities and soil physicochemical properties.
Recently, transplantation of cryopreserved ovarian tissue is the method for fertility preservation for oncologic and nononcologic reasons. The main challenge of ovarian cryopreservation followed by ...transplantation is that ischemia reperfusion injury (IRI) induced the loss of follicles. The aim of this study was to evaluate the effects of glutathione (GSH), ulinastatin (UTI) or both (GSH+UTI) on preventing ischemia reperfusion-induced follicles depletion in ovarian grafts.
Ovarian fragments were collected from 20 women aged 29±6 years. Frozen-thawed human ovarian tissue was xenografted into SCID mice, at the same time GSH, UTI and GSH+UTI was administrated respectively. The ovarian grafts were collected at the 1st, 3rd, 7th, 14th, 28th, 56th, and 85th day after xenotransplantation. Follicle survival rate was measured by H&E staining and Live/Dead staining. Angiogenic activity and macrophage recruitment was evidenced by immunohistochemical staining. The oxidative stress and inflammatory cytokines in human ovarian xenografts were measured by real-time PCR. The results indicated that after the treatments of GSH, UTI and GSH+UTI in the hosts, follicular survival in ovarian grafts were improved. The level of VEGF, CD31, and antioxidant enzymes superoxide dismutase 1 and superoxide dismutase 2 in ovarian grafts were increased. Accumulation of macrophages, level of IL6 and TNF-α, as well as malondialdehyde was decreased in ovarian grafts from treated groups. In conclusion, administration of GSH, UTI and GSH+UTI decreased the depletion of follicles in human grafts post-transplantation by inhibiting IRI-induced antiangiogenesis, oxidative stress and inflammation.
The effects of high-energy electropulsing treatment (EPT) on the microhardness and corrosion behavior of the surface gradient oxide coating on the titanium alloy matrix were investigated using ...infrared thermoscope, micro-hardness, three-dimensional optical microscope, electrochemical work station, scanning electron microscope equipped with electron backscatter diffraction, X-ray Diffraction, Fourier Transform Infrared Spectroscopy and Thermogravimetry analyzer. Results showed that the surface modification brings in surface strengthening effect and improved surface corrosion resistance performance (in the fluoridated acidified artificial saliva) of titanium alloy strips with outstanding bonding-strength oxide coating through EPT transition zone. Rapid recrystallization, grain growth and texture evolution of surface matrix alloy are present with increasing DAFA (distance from the anode) of EPT. In this process, microstructure/texture evolution influences the oxidation layer thickness and the oxidation rate with the relationship between these two parameters fitting the approximate positive linear equation and the turning trend located at 120mm DAFA. Compared with TG-traditional furnace heating process, the growth rate of oxidation under EPT is noticeably enhanced by two orders of magnitudes and surface oxide coating experiences a crystal transformation from anatase-TiO2 to rutile-TiO2. Ionization and acceleration of oxygen by EPT are put forward to discuss the accelerated growth and crystal transformation kinetics of the oxidation process. Therefore, improved surface wear resistance and anti-corrosion performance with a strong adherent gradient oxide coating on the titanium alloy strips surface can be achieved by highly-efficient EPT process which can be applied in biomedical applications.
Abundant food resources in riparian zones provide efficient foraging sites for waterbirds. Herbivory is a key ecosystem process that has widely recognized effects on primary production and vegetation ...structure and composition. However, there is limited understanding of impacts of waterbird herbivory on riparian zone vegetation. In this study, a bird exclosure experiment with five levels of foraging intensities (no foraging, very little foraging, light foraging, moderate foraging and heavy foraging) was set up in Shengjin Lake to study the effects of waterbird foraging on the community structure of sedge meadows and individual traits of the dominant plant Carex thunbergii. Foraging intensity had little effect on community structure. The dry mass of C. thunbergii decreased with the increasing foraging time. Waterbird foraging reduced leaf dry mass under heavy foraging by 27.7% and root dry mass by 45.6% compared to CK (no foraging). Waterbird foraging increased allocation to shoot growth but had a weak effect on elemental allocation of C. thunbergii. The foraging intensity significantly affected the morphological traits of C. thunbergii. The results of structural equation modeling showed that RSR (root: shoot ratio represents the ratio of dry mass) and RL (root length) are key traits in driving the dry mass decline in the presence of bird foraging. This study may contribute to a better understanding of the adaptability of perennial herb plants to waterbird foraging and maintain the healthy development of wetland ecosystems.
Microstructure, mechanical properties, electrical resistivity and temperature evolution of functionally graded Ti-6Al-4V alloy strips were processed under the electro-pulsing treatment (EPT) for 16 s ...and further studied by optical microscope, scanning electron microscopy, X-ray diffraction, electrical resistivity measurement, mechanical testing and consecutive temperature testing. Six kinds of microstructures were obtained on the single functional graded material (FGM) by different EPT parameters. The temperature evolution of each processing parameter was measured timely to be found low and different as a proof of the coupling of thermal and athermal effect in the FGM-EPT procedure. With increasing the frequency, the volume of beta phase increased gradually in general and re-dissolution both occurred. The ductility for sectional samples of FGM was enhanced to the maximum value, elongation to failure 27.8%, without compromising too much ultimate tensile strength and relevant tensile fracture behaviors were changed. The mechanism of microstructure change was discussed by the coupling of the thermal and athermal effect of EPT to decrease the thermodynamic barrier and influence the dislocations and atoms motion.
Citrus canker, caused by the bacterium
subsp.
(
), seriously affects fruit quality and yield, leading to significant economic losses around the world. Understanding the mechanism of
virulence is ...important for the effective control of
infection. In this report, we investigate the role of a protein named HemK in the regulation of the virulence traits of
. The
gene was deleted in the
jx-6 background, and the Δ
mutant phenotypically displayed significantly decreased motility, biofilm formation, extracellular enzymes, and polysaccharides production, as well as increased sensitivity to oxidative stress and high temperatures. In accordance with the role of HemK in the regulation of a variety of virulence-associated phenotypes, the deletion of
resulted in reduced virulence on citrus plants as well as a compromised hypersensitive response on a non-host plant,
. These results indicated that HemK is required for the virulence of
. To characterize the regulatory effect of
deletion on gene expression, RNA sequencing analysis was conducted using the wild-type
jx-6 strain and its isogenic Δ
mutant strain, grown in XVM2 medium. Comparative transcriptome analysis of these two strains revealed that
deletion specifically changed the expression of several virulence-related genes associated with the bacterial secretion system, chemotaxis, and quorum sensing, and the expression of various genes related to nutrient utilization including amino acid metabolism, carbohydrate metabolism, and energy metabolism. In conclusion, our results indicate that HemK plays an essential role in virulence, the regulation of virulence factor synthesis, and the nutrient utilization of
.
Aquatic vegetation has been restored since the removal of seine nets from the lake surface of Shengjin Lake in 2018. Through four seasons of phytoplankton sampling surveys from 2019–2020, we analyzed ...spatial and temporal changes in phytoplankton communities, water quality, and aquatic plant recovery in conjunction with previous research literature to reveal the response mechanisms of phytoplankton community structure to rapidly recovering aquatic vegetation. The results showed that the Secchi depth increased (0.4 m to 0.7 m), the concentration of total phosphorus decreased (0.053 mg/L to 0.41 mg/L), the species of aquatic plants (5 species to 16 species), phytoplankton species (210 species to 254 species) and cell density increased after the removal of the seine. Since the removal of the seine of Shengjin Lake, the aquatic vegetation cover has exceeded 80%, the phytoplankton biodiversity has increased, and the water quality has recovered to II-III water status. Our results show that aquatic plants improve water quality through direct and indirect effects and influence phytoplankton community structure together with the water environment, which can provide guidance for the restoration situation of the middle and lower reaches of the Yangtze River through-river lake ecosystems.
Flood events can significantly affect the physical and biological processes of aquatic ecosystems in a short time, leading to rapid changes in phytoplankton community structure. The Huayanghe Lakes ...experienced extreme flooding in the summer of 2020, with the water level reaching 16.42 m. In order to understand the effects of flooding on phytoplankton diversity and community structure, eight samples were collected in the Huayanghe Lakes from 2019 to 2020. Water-level disturbance has a significant influence on lake-water quality and phytoplankton community structure. The results showed that the Secchi depth increased from 65.36 to 8.52 cm, while the concentration of total nitrogen (from 0.98 to 0.7 mg/L) and total phosphorus (from 0.04 to 0.031 g/L) decreased. In addition, flooding significantly increased the Shannon–Wiener diversity index, the Pielou index, and the Margalef richness index by an average of 43.5%, 36.7%, and 40.21%, respectively. The phytoplankton community structure in the Huayanghe Lakes changed due to the change of physicochemical environment caused by flood. While in the pre-flood period phytoplankton was composed of large diatoms (e.g., Aulacoseira granulata), cyanobacteria (e.g., Microcystis sp., Anabaena sp., and Aphanizomenon sp.) and other multicellular taxa, the flood period showed an increase in the proportion of chlorophytes and diatoms that quickly adapted to settle in new environments. Pearson correlations and redundancy analyses showed that water level fluctuation was the most significant environmental factor affecting the phytoplankton community between the regular hydrological cycle and flood periods. There are few studies on phytoplankton in the Huayanghe Lakes, and the present study provides basic data on phytoplankton diversity and community structure. In addition, it provides a theoretical basis for controlling water level change in the Yangtze River.
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