Determination of Vanadium Isotope Compositions in Carbonates Using an Fe Coprecipitation Method and MC-ICP-MS.

Vanadium isotope compositions (δ(51V)) in marine carbonates are a potential proxy to trace global redox states of ancient oceans. Although high-precision δ(51V) analyses are available for many geological materials, carbonate-hosted δ(51V) data have not been reported yet due to extremely high matrix elements and low V contents (generally below 10 µg g-1). In this study, we developed an Fe coprecipitation method combined with an Fe column to preconcentrate V from the major matrix elements and subsequent four-step chromatographic procedures to further purify V in carbonates. The δ(51V) values were measured using a sample-standard bracketing method by MC-ICP-MS. The robustness of this method was assessed by analyzing element-doped and matrix-spiked synthetic carbonate solutions containing an in-house δ(51V) standard, USTC-V. The mean δ(51V) value of the synthetic carbonate solutions (0.06 ± 0.08‰; 2SD, n = 33) is in good agreement with the recommended value of the USTC-V relative to the Oxford AA solution (0.07 ± 0.08‰; 2SD, n = 347). In addition, the consistency in the δ(51V) value of the igneous carbonatite standard, COQ-1, which was processed in parallel with the whole purification (-0.48 ± 0.04‰; 2SD, n = 3) and a four-step chromatographic procedure (-0.43 ± 0.08‰; 2SD, n = 3), further validates the robustness of our method. For the first time, we obtained δ(51V) values of four carbonate reference materials: JDo-1, -0.56 ± 0.09‰ (2SD, n = 27); JLs-1, -0.61 ± 0.14‰ (2SD, n = 33); GBW07217a, -0.79 ± 0.09‰ (2SD, n = 6); GBW07214a, -0.51 ± 0.13‰ (2SD, n = 48). The long-term external precision of carbonate-hosted δ(51V) analyses is better than ±0.14‰ (2SD). Our method can be applied to measure carbonate-hosted δ(51V) to trace the evolution in global marine redox states throughout the Earth's history.

[Penile frenulum lengthening for premature ejaculation].

OBJECTIVE: To evaluate the effect of penile frenulum lengthening in the treatment of premature ejaculation (PE). METHODS: Thirty-four males with PE were enrolled in this study, of whom 8 had received circumcision six months before and 4 had redundant prepuce, all with short frenulum. Those with a history of circumcision underwent reconstruction and lengthening of the frenulum, and those without received frenulum lengthening only. RESULTS: Compared with the baseline, the intravaginal ejaculation latency time (IELT) was significantly increased at 1 month after operation ([1.35 ± 0.49] vs [5.71 ± 2.69] min, t = -9.42, P <0.01), (1.42 ± 0.5) vs (5.31 ± 2.74) min in the patients without circumcision (t = -7.41, P <0.01), (1.12 ± 0.35) vs (7.00 ± 2.20) min in those with circumcision (t = -7.24, P <0.01), and (1.50 ± 0.58) vs (4.75 ± 1.71) min in those with redundant prepuce (t = -3.81, P <0.05). Totally, 94% of the patients were satisfied with their sexual intercourse postoperatively. CONCLUSION: Penile frenulum plays an important role in penile erection. Reconstruction and/or lengthening of the frenulum can prolong penile erection and IELT in PE patients.

[Study on microRNA expression in endometrium of luteal phase and its relationship with infertility of endometriosis].

OBJECTIVE: To study the different expression of microRNA(miRNA) including mir-29c, mir-200a, mir-145 in the mid-secretary endometrium and its relationship with infertility of endometriosis. METHODS: From August 2011 to February 2013, 36 infertile cases with endometriosis confirmed by laparoscopy and pathology and excluded the other infertile factors in Department of Reproductive Medicine in Peking University Shenzhen Hospital were enrolled in this study, which were divided into 17 cases with stage I-II, 19 cases with stage III-IV according to the revised classification American Fertility Society. Forty-four healthy women with male factor infertility were chosen as control group. The relative expression levels of mir-29c, mir-200a, mir-145 in the endometrium of women in two groups were detected by using real-time quantitative polymerase chain reaction. Those women were followed up for pregnancy outcome of endometriosis group after assisted reproductive techniques (pregnancy and non-pregnancy group respectively). RESULTS: (1) The expression of miRNA between endometriosis and control groups:the average expression level of mir-29c, mir-200a, mir-145 in the endometrium of endometriosis group was 2.46 ± 1.98, 3.20 ± 2.45, 6.378 ± 3.275, which were significantly higher than 1.36 ± 1.05, 2.04 ± 1.16, 4.548 ± 1.885 in control group (P = 0.026, 0.027, 0.041, respectively). (2) The expression of miRNA between I-II stage and III-IV: the average expression level of mir-29c, mir-200a, mir-145 in the endometrium was 0.53 ± 0.51, 0.33 ± 0.26, 0.048 ± 0.021 in patients with of stage I-II, while 0.26 ± 0.18, 0.28 ± 0.12, 0.045 ± 0.016 in stage III-IV respectively, there were no statistically significant differences between the two groups (P = 0.191,0.661,0.753, respectively) . (3) The expression of miRNA between pregnancy and non-pregnancy groups:the average expression level of mir-29c, mir-200a, mir-145 in the endometrium were 0.60 ± 0.30, 1.23 ± 0.48, 0.886 ± 0.238 in pregnancy group, while 2.64 ± 1.73, 4.39 ± 2.58, 7.199 ± 3.945 in non pregnancy group, there were statistically significant differences between the two groups (P = 0.030,0.039,0.028, respectively). CONCLUSION: Up-regulation of mir-29c, mir-200a, mir-145 in the endometrial tissue might play a role in endometriosis associated infertility.