Experimental Investigation on Seepage Characteristics of Clay-Structure Interface after Shear Deformation.

There exist shear and seepage behaviors on the interface between clay core and concrete slab in clay core dams. In order to investigate the seepage characteristics of the clay-structure interface after shear deformation, a shear-seepage test system is proposed, in which the seepage direction is perpendicular to the shear direction. The shear test and shear-seepage test are performed on clay-metal and clay-mortar interfaces under different normal stresses (100, 200, 400, 800, and 1600 kPa). The shear stress-deformation curves of two clay-structure interfaces exhibit softening behavior and residual friction behavior. The interface roughness can enhance peak and residual shear strength and increase peak displacement. The shear-seepage test results show that specimen permeability decreases first and then increases to a stable value as shear deformation increases under low normal stress, while it decreases continuously and then retains stability under high normal stress. The interface roughness enhances specimen permeability under low normal stress, whereas it has a weak effect on specimen permeability under high normal stress. Compared with initial permeability, shear deformation reduces specimen permeability rather than raise it. The ratio of stabilized permeability coefficient to initial value ranges from 0.6 to 0.8. The clay-structure interface still has a good resistance to seepage failure after shear deformation. The shear dilation features and interface pore decrease caused by shear behavior are the internal attributions of clay-structure specimen permeability evolution.

The function of nuclear hormone receptor 4A signaling in the human reproductive system: A review.

AIM: This review aims to summarize the research focused upon the functions of nuclear hormone receptor 4A (NR4A) in the human reproductive system. The research questions addressed are to decipher what role the NR4A subfamily plays in the regulation of the human reproductive system and effects upon fertility issues through regulation of the expression of the NR4A subfamily. METHODS: The electronic database PubMed was searched for studies published before November 2021. Keywords included "NR4A," "trophoblast," "decidualization," "folliculogenesis," "estrogen," "pregnancy," "Leydig cells," "fertility," and "reproductive." Relevant references from retrieved manuscripts and review articles were also searched manually. RESULTS: NR4A subfamily are involved in trophoblast differentiation, endometrial decidualization, embryo adhesion, secretion of related hormones, and regulation of spontaneous term labor. Besides, many studies have provided strong evidence that they play critical roles in spermatogenesis. Furthermore, Multiple mechanisms can affect the expression of NR4As. Broadly, NR4A family receptors affect the human reproductive system in multiple ways. CONCLUSIONS: Further research is needed to specifically dissect the functions and regulatory mechanisms of these receptors and their pharmaceutical antagonists and agonists. The connection between the NR4A subfamily and a variety of reproductive disorders needs to be proven experimentally such that further examination of human tissue is required to assess the role of these receptors in human reproductive diseases.

Women with high telomerase activity in luteinised granulosa cells have a higher pregnancy rate during in vitro fertilisation treatment.

OBJECTIVE: To study the effect of telomerase activity (TA) in human luteinised granulosa cells (GCs) on the outcome of in vitro fertilisation treatment. METHODS: Fifty-six women, aged 23 to 39 years, were enrolled and divided into four groups according to their levels of TA. RESULTS: Seventeen cases in group A exhibited nondetectable TA, 16 cases in group B expressed low levels of TA (between 0.1 and 0.65 OD × mm), 14 cases in group C expressed moderate TA levels (between 0.66 and 1.00 OD × mm) and 9 cases in group D expressed high levels of TA (more than 1.00 OD × mm). The level of total serum testosterone (T) was significantly higher in groups C and D than in group A (1.43±0.10 vs. 1.08±0.11 nmol/L, P<0.030 and 1.56±0.08 vs. 1.08±0.11 nmol/L, P<0.005, respectively). The TA level was positively correlated with T (r=0.291, P<0.011). No obvious differences were observed in rates of fertilisation, cleavage, mature oocyte formation or good-quality embryos among the groups. The patients in group D exhibited the highest rates of embryo implantation and clinical pregnancy (with rates of 52.63% and 77.78%, respectively, compared with 18.92% and 29.41% in group A, 25.71% and 37.50% in group B and 48% and 50% in group C, with P<0.018 and P=0.112, respectively). The patients in group D also had a greater likelihood of becoming pregnant than those in group A (OR: 9.703, P < 0.023), group B (OR: 14.765, P<0.009) or group C (OR: 5.560, P=0.103). CONCLUSIONS: Luteinised GCs have a certain potential for proliferation and TA of luteinised GCs may predict the clinical outcomes of IVF treatment. Some unknown regulatory mechanisms between TA and T should be studied in further trials.

[Effects of gonadotropin releasing hormone analogues on chemotherapy-induced ovarian function damage in rats].

OBJECTIVE: To investigate the effects of gonadotropin releasing hormone agonist (GnRH-a) and antagonist (GnRH-ant) on cyclophosphamide (CTX)-induced ovarian damage in rats. METHODS: Seventy-two Sprague-Dawley female rats were divided randomly into six groups, which received normal saline (NS), CTX, GnRH-a + NS, GnRH-a + CTX, GnRH-ant + NS, and GnRH-ant + CTX respectively. Levels of serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E(2)) were measured successively by the enzyme-linked immunosorbent assay method, and half of the rats were killed in the first week and between the fourth and the fifth week after stop of medication, respectively to compare the weight of the ovaries and the number of the primordial follicles and the growth follicles. RESULTS: (1) Throughout experiment, the serum levels of FSH, LH and E(2) of the control group fluctuated slightly, while those in the CTX group kept rising. During medication treatment, compared with the control group [(118 +/- 16) microg/L, (350 +/- 35) microg/L] and the CTX group [(113 +/- 15) microg/L, (289 +/- 42) microg/L], the concentrations of LH [(42 +/- 8) - (47 +/- 7) microg/L, (31 +/- 5) - (36 +/- 7) microg/L] and FSH [(124 +/- 45) - (136 +/- 32) microg/L, (178 +/- 54) - (198 +/- 27) microg/L] in the GnRH-a groups and the GnRH-ant groups were maintained at low levels significantly and the levels of LH in the GnRH-ant groups were significantly lower than that in the GnRH-a groups, but the levels of FSH in the GnRH-ant groups were significantly higher than that in the GnRH-a groups (P < 0.05); and extremely different from the GnRH-a groups [(0.98 +/- 0.18) - (1.46 +/- 0.22) ng/L], the level of E(2) of the GnRH-ant groups [(3.58 +/- 0.43) - (3.98 +/- 0.74) ng/L] did not significantly decrease (P < 0.01). After stop of therapy, the concentrations of LH, FSH and E(2) in the GnRH-a groups and the GnRH-ant + NS group rose gradually and were similar to the levels of the control group (P > 0.05), but the levels of FSH, LH and E(2) of the GnRH-ant + CTX group rose obviously and were similar to the levels of the CTX group, especially the FSH , and the levels of LH and FSH of the GnRH-ant + CTX group [(156 +/- 12) microg/L, (520 +/- 44) microg/L] and the CTX group [(178 +/- 18) microg/L, (546 +/- 36) microg/L] were significantly higher than that of the other four groups [(121 +/- 15) - (132 +/- 13) microg/L, (335 +/- 35) - (359 +/- 26) microg/L] at the 4(th) - 5(th) week after stop of treatment (P < 0.05). (2) At the 1(st) week after stopping therapy, the GnRH-a + NS group [(12 +/- 5) mg/100 g]and the GnRH-a + CTX group [(18 +/- 8) mg/100 g] had the lowest weight of ovaries which was significantly different from the other groups [(30 +/- 9) - (37 +/- 8) mg/100 g, P < 0.05]. At the 4(th) - 5(th) week after stopping therapy, the GnRH-ant + CTX group [(22 +/- 6) mg/100 g] and the CTX group [(20 +/- 4) mg/100 g] had the lowest weight of ovaries which were significantly different from the other groups [(29 +/- 5) - (31 +/- 9) mg/100 g, P < 0.05]. (3) At the 1(st) week after stopping therapy, there were the largest number of primordial follicles [(824 +/- 45), (689 +/- 39)] and the lowest number of growth follicles [(15 +/- 1), (21 +/- 3)] in the GnRH-a + NS group and the GnRH-a + CTX group, but there were the lowest number of primordial follicles [(255 +/- 24), (343 +/- 29)] and the largest number of growth follicles [(110 +/- 21), (87 +/- 17)] in the GnRH-ant + CTX group and the CTX group. At the 4(th) - 5(th) week after stopping therapy, the number of growth follicles in the GnRH-a + NS group (58 +/- 11) and the GnRH-a + CTX group (56 +/- 16) recovered to almost the level of the control group (57 +/- 9, P > 0.05), but the number of all kinds of follicles declined significantly in the GnRH-ant + CTX group [(195 +/- 15), (36 +/- 12)] and the CTX group [(212 +/- 11), (36 +/- 9)] compared to the other four groups [(302 +/- 15) - (690 +/- 43), (44 +/- 12) - (58 +/- 11), P < 0.05]. CONCLUSION: In rat model, GnRH-a prevents the ovarian function damage induced by CTX, but GnRH-ant does not show similar protective effect.

[Correlation between local hormones and CD36 transcription level in women with polycystic ovary].

OBJECTIVE: To detect CD(36) expressions in polycystic ovary (PCO), and to explore its correlation with local androgen and insulin at transcription level. METHODS: From August 2002 to February 2003, 12 patients with asymmetric PCO, 15 primary or secondary infertile patients without endocrine disorders and 8 polycystic ovary syndrome (PCOS) with bilateral PCO were recruited. Extraction of follicular fluid and detection of testosterone (T), dehydroepiandrosterone sulfate (DHEAS), insulin (INS) and androstenedione (A(2)) were performed. Relative CD(36) mRNA expression level of human ovarian inner thecal cells was analyzed by auto image analysis system (IAS) after RT-PCR. RESULTS: The level of CD(36) mRNA expression in thecal cells was 0.24 +/- 0.07 in polycystic ovary of PCO group and 0.21 +/- 0.05 in bilateral ovaries of PCOS group, respectively, which were significantly lower than 0.83 +/- 0.13 in normal ovaries (P < 0.01). T and INS levels of follicle fluid in PCO were significantly higher than that in normal ovaries (P < 0.01). T and INS levels of follicle fluid were negatively related to CD(36) mRNA expression of follicular theca interna (r = -0.6810, r = -0.6708, P < 0.01). CONCLUSION: Decrease of scavenger receptor gene CD(36) mRNA may play a role in the pathogenesis of PCO by increasing the level of T and INS in follicular fluid.