Effect of drying cracks on swelling and self-healing of bentonite-sand blocks used as engineered barriers for radioactive waste disposal

Experiments were conducted to evaluate the healing of drying cracks in air-dried bentonite-sand blocks after hydration and swelling in groundwater,providing justifications to simplify the protection of blocks prior to installation in a high-level radioactive waste repository.Synthetic groundwater was prepared to represent the geochemistry of Beishan groundwater,and was used to hydrate the blocks during the swelling pressure and swelling strain measurements,as Beishan is the most promising site for China's repository.Healing of the surface cracks was recorded by photography,and healing of the internal cracks was visualized by CT images and hydraulic conductivity of air-dried blocks.The results indicate that the maximum swelling pressure and swelling strain are primarily affected by the geochemistry of Beishan groundwater,but not affected by the drying cracks.The maximum swelling pressure and swelling strain of air-dried blocks are comparable to or even higher than the pressure and strain of fresh blocks.The maximum swelling pressure measured in strong(i.e.high ion strength)Beishan groundwater was 44%of the pressure measured in deionized(DI)water,and the maximum swelling strain was reduced to 23%of the strain measured in DI water.Nevertheless,the remained swelling of the blocks hydrated in strong Beishan groundwater was sufficient to heal the surface and internal drying cracks,as demonstrated by the pictures of surface cracks and CT images.The hydraulic conductivity of the air-dried block permeated with strong groundwater was comparable(3.7×higher)to the hydraulic conductivity of the fresh block,indicating the self-healing of drying cracks after hydration and swelling in groundwater.A simplified method of protecting the block with plastic wraps before installation is recommended,since the remained swelling of the block hydrated in Beishan groundwater is sufficient to heal the drying cracks.

Isorhamnetin protects porcine oocytes from zearalenone-induced reproductive toxicity through the PI3K/Akt signaling pathway

Background Zearalenone(ZEA)widely exists in moldy grains,which seriously destroys the fertility of females.Isorhamnetin,a natural flavonoid,has extensive of pharmacological activities.However,the beneficial effect and the underlying molecular mechanism of isorhamnetin involvement in ZEA-induced porcine oocyte damage have not been investigated.Methods Oocytes were treated with different concentrations of ZEA(3,5,8 and 10μmol/L)and isorhamnetin(5,10,20 and 30μmol/L)for 44 h at 39℃.ZEA(5μmol/L)and isorhamnetin(10μmol/L)were selected for subsequent studies.Polar body exclusion rate,apoptosis rate and apoptosis related proteins,ROS levels and SOD2 protein,mitochondrial membrane potential and distribution,endoplasmic reticulum distribution and proteins expression,and PI3K,Akt and p-Akt proteins expression of oocytes were detected.In addition,the effect of PI3K antagonist(LY294002)on oocyte nuclear maturation and apoptosis were used to determine the involvement of PI3K/Akt signaling pathway.Results Our findings showed that ZEA exposure damaged oocytes and isorhamnetin therapy restored the developmental capability of porcine oocytes.Isorhamnetin promoted polar body extrusion rate to rescue ZEA-induced meiotic arrest in porcine oocytes.Isorhamnetin alleviated ZEA-induced oxidative stress by stimulating SOD2 protein expression and inhibiting ROS production.Moreover,isorhamnetin enhanced normal mitochondrial distribution and mitochondrial membrane potential to prevent mitochondrial dysfunction induced by ZEA.Changing the expression of endoplasmic reticulum stress-related marker proteins(CHOP,GRP78)and the distribution rate of normal endoplasmic reticulum showed that isorhamnetin relieved ZEA-caused endoplasmic reticulum stress.Mechanistically,isorhamnetin decreased Bax/Bcl-2 protein expression and inhibited ZEA-induced apoptosis through PI3K/Akt signaling pathway.Conclusions Collectively,these results suggest that isorhamnetin protects oocytes from ZEA-caused damage through PI3K/Akt signaling pathway,which enhances meiotic maturation and mitochondrial function,and inhibits early apoptosis,oxidative stress and endoplasmic reticulum stress in porcine oocytes.Our study provides a new strategy for solving the reproductive toxicity induced by ZEA and treating woman infertility.

Functional connectivity of the default mode network subsystems in patients with major depressive episodes with mixed features

Background The neuroimaging mechanism of major depressive episodes with mixed features(MMF)is not clear.Aims This study aimed to investigate the functional connectivity of the default mode network(DMN)subsystems among patients with MMF and patients with major depressive disorder without mixed features(MDD_(noMF)).Methods This study recruited 47 patients with MDD_(noMF)and 27 patients with MMF from Beijing Anding Hospital,Capital Medical University,between April 2021 and June 2022.Forty-five healthy controls(HCs)were recruited.All subjects underwent resting-state functional magnetic resonance imaging scanning and clinical assessments.Intranetwork and internetwork functional connectity were computed in the DMN core subsystem,dorsal medial prefrontal cortex(dMPFC)subsystem and medial temporal lobe(MTL)subsystem.Analysis of covariance method was performed to compare the intranetwork and internetwork functional connectivity in the DMN subsystems among the MDD_(noMP)MMF and HC groups.Results The functional connectivity within the DMN core(F=6.32,P_(FDR)=0.008)and MTL subsystems(F=4.45,P_(FDR)=0.021)showed significant differences among the MDD_(noMP) MMF and HC groups.Compared with the HC group,the patients with MDD_(noMF) and MMF had increased functional connectivity within the DMN MTL subsystem,and the patients with MMF also showed increased functional connectivity within the DMN core subsystem.Meanwhile,compared with the MDD_(noMP) the patients with MMF had increased functional connectivity within the DMN core subsystem(mean difference(MDD_(noMF)-MMF)=-0.08,SE=0.04,p=0.048).However,no significant differences were found within the DMN dMPFC subsystem and all the internetwork functional connectivity.Conclusions Our results indicated abnormal functional connectivity patterns of DMN subsystems in patients with MMF,findings potentially beneficial to deepen our understanding of MMF's neural basis.

Suppressing the donor-like effect via fast extrusion engineering for high thermoelectric performance of polycrystalline Bi_(2)Te_(2.79)Se_(0.21)

Bi2Te3-based alloys are the most mature commercial thermoelectric(TE)materials for the cooling application near room temperature.However,the poor mechanical properties of the commercial zone melting(ZM)ingot severely limits the further application.Meanwhile,due to the donor-like effect,the robust polycrystalline n-type bulks usually have low TE performance near room temperature.Herein,based on the commercial ZM ingots,a high figure of merit(zT)of 1.0 at 320 K and good mechanical properties are achieved via the hot extrusion.The dynamic recrystallization in the hot-extrusion process can suppress the donor-like effect and refine the large ZM grains into fine-equiaxed grains.Moreover,the obtained polycrystalline Bi2Te2.79Se0.21 has good preferential orientation and high carrier mobility(m).The high m and the weaken donor-like effect maintain the high power factor(PF)of 43.1 mW cm^(-1)K^(-2)in the hot-extruded ZM sample.Due to the enhanced phonon scattering,the total thermal conductivity ktot decreased to 1.35 W·m^(-1)·K^(-1).To demonstrate the good mechanical properties of the extruded ZM sample,micro TE dices with the cross sections of 300μm×300 mm and 200μm×200 mm are successfully cut from the extrusion sample.This study provided a fast and low-cost extrusion technique to improve the TE and mechanical properties of the commercial ZM ingot at room temperature.

Isorhamnetin protects zearalenone-induced damage via the PI3K/Akt signaling pathway in porcine ovarian granulosa cells

Zearalenone(ZEA)is widely derived from moldy cereal grain,which has adverse effects on animal reproduction.In particular,pigs are more sensitive to ZEA-induced toxicity than other animals.Isorhamnetin has extensive pharmacological activity.However,the role of isorhamnetin in ZEA-induced cytotoxicity remains unclear.This study was designed to investigate the therapeutic effect of isorhamnetin on ZEA-induced damage in porcine ovarian granulosa cells and elucidate its molecular mechanism.Two experiments were conducted,where a minimum of 3 biological replicates were used for each treatment.In Exp.1,ovarian granulosa cells were treated with different concentrations of isorhamnetin(1,5,10,20 and 30μmol/L)and ZEA(0,10,30,60,90 and 120μmol/L)for 24 h.Our results indicated that 60μmol/L ZEA(half-maximal inhibitory concentration value)and 20μmol/L isorhamnetin(the most effective concentration against ZEA-induced cytotoxicity)were optimum concentrations.In Exp.2,ovarian granulosa cells were treated with isorhamnetin(20μmol/L)for 2 h,before treatment with ZEA(60μmol/L)for 24 h.Apoptosis,endoplasmic reticulum stress,oxidative stress,proliferation and hormone secretion of ovarian granulosa cells were detected.Our findings showed that isorhamnetin suppressed(P<0.05)ZEA-induced apoptosis by altering mitochondrial membrane potential and apoptosis-related proteins(B-cell lymphoma-2[Bcl-2],Bcl2-associated x[Bax]and cleaved caspase-3[C-Casp3]).Changes in intracellular Ca2+levels and C/EBP homologous protein(CHOP),recombinant activating transcription factor 6(ATF6),glucose regulated protein78 k D(GRP78)indicated that isorhamnetin rescued(P<0.05)ZEA-induced endoplasmic reticulum stress.Furthermore,isorhamnetin prevented(P<0.05)ZEA-induced oxidative stress via the mitogen-activated protein kinase(P38)signaling pathway.Mechanistically,isorhamnetin stimulated(P<0.05)the expression of proliferating cell nuclear antigen(PCNA)and cyclin D,thereby increasing the ratio of S phase cells in response to ZEAinduced apoptosis via phosphatidylinositol 3 kinase/protein kinase B(PI3K/Akt)signaling pathway.Isorhamnetin also recovered(P<0.05)ZEA-induced steroidogenesis disorder by regulating steroidogenic enzyme gene and proteins(follicle-stimulating hormone receptor[FSHR]and cytochrome P450 family 19subfamily a member 1[CYP19A1]).Collectively,these findings show that isorhamnetin protects ovarian granulosa cells from ZEA-induced damage,which promotes proliferation,alleviates apoptosis,endoplasmic reticulum stress,oxidative stress,and steroidogenesis disorder.

Transcript profile of CLSTN3B gene in human white adipose tissue is associated with obesity and mitochondrial gene program

Dear Editor,Obesity is a major health issue with global prevalence and increases the risk of many metabolic diseases.Of particular con-cern is the increasing incidence of type 2 diabetes,the primary causes of which are obesity-driven insulin resistance in white adipose tissue(WAT),skeletal muscle,and liver,and decreased insulin secretion by pancreaticβ-cells[1].

POSITIVE PERIODIC SOLUTIONS OF THE FIRST-ORDER SINGULAR DISCRETE SYSTEMS

In this paper, we study two kinds of first-order singular discrete systems. By the fixed point index theory, we investigate the existence and multiplicity of positive periodic solutions of the systems.