真空蒸馏制备高纯金属的研究进展

随着科学技术的发展,高新技术产业对金属的纯度要求越来越高。然而,痕量杂质的存在会对金属的性能产生不良影响。真空蒸馏工艺因其金属回收率高、环保性能好、设备简单等优点,被广泛应用于制备高纯金属。本文作者围绕真空蒸馏的原理和工艺,系统地总结了高纯金属制备的总体进展。介绍了真空蒸馏的原理、真空蒸馏炉的改进设计、参数优化和仿真模拟。根据该技术制备高纯金属的现状,指出在科学研究中机理研究和仿真模拟是必不可少的。本研究对提高生产效率、节约生产成本及提高金属纯度具有一定的借鉴意义。

采用钛阴极从碱液中旋流电积回收镓

为了抑制浓差极化并提高电流效率,提出一种旋流电解法回收镓的工艺。通过电化学研究确定GaO_(2)^(-)在120 g/L NaOH溶液中的扩散系数为1.65×10^(-7)cm^(2)/s。考察各种参数对镓电积的影响,确定电积的最佳条件为:钛阴极、电流密度750 A/m^(2)、镓浓度39.9 g/L、NaOH浓度120 g/L、循环流量200L/h。在这些条件下,电积的电流效率和镓回收率分别为47.9%和90.2%。析出的镓较易从阴极上分离,经过洗涤后的镓最终纯度为99.993%。镓旋流电积能耗约为9048 kW·h/t。该研究表明旋流电积是一种具有高电流效率和低能耗的有前途的镓生产工艺。

Research and application of the angular rolling technology for plate mill

Angular rolling technology can overcome the size limitation of plate mill equipment and product heavy steel plate with large unit weight or improve the production efficiency of small width spreading ratio product.With the DEFORM software,the numerical simulation study of the angular rolling process was carried out,and the relation laws of the width,rolling force and strain of the rolled piece under different angular rolling process conditions were obtained.The simulation results show that with the rotation angle increasing,the width of the rolled piece increases.Comparing with the conventional rolling process,the rolling force changes gradually during the biting and throwing stage of the angular rolling pass.With the rotation angle increasing,both the equivalent strains in the thickness direction and in the width direction gradually increase.According to the pattern and dimension's changing formula in the double-pass angular rolling process,the prediction model of angle,reduction and width spreading is built.The opening value of side guide is set for the rotation angle controlling.For one 5000 mm heavy plate mill,the automation control system was modified,and the angular rolling technology was applied online.The absolute deviation of target width does not exceed±20 mm and the relative deviation does not exceed 1%.The large unit weight plate that cannot be rolled with traditional process,can be produced now,and the annual output increases by 10000 t.

Identification of a novel splice site mutation in the DNAAF4 gene of a Chinese patient with primary ciliary dyskinesia

Primary ciliary dyskinesia(PCD)is a rare hereditary orphan condition that results in variable phenotypes,including infertility.About 50 gene variants are reported in the scientific literature to cause PCD,and among them,dynein axonemal assembly factor 4(DNAAF4)has been recently reported.DNAAF4 has been implicated in the preassembly of a multiunit dynein protein essential for the normal function of locomotory cilia as well as flagella.In the current study,a single patient belonging to a Chinese family was recruited,having been diagnosed with PCD and asthenoteratozoospermia.The affected individual was a 32-year-old male from a nonconsanguineous family.He also had abnormal spine structure and spinal cord bends at angles diagnosed with scoliosis.Medical reports,laboratory results,and imaging data were investigated.Whole-exome sequencing,Sanger sequencing,immunofluorescence analysis,hematoxylin-eosin staining,and in silico functional analysis,including protein modeling and docking studies,were used.The results identified DNAAF4 disease-related variants and confirmed their pathogenicity.Genetic analysis through whole-exome sequencing identified two pathogenic biallelic variants in the affected individual.The identified variants were a hemizygous splice site c.784-1G>A and heterozygous 20.1 Kb deletion at the DNAAF4 locus,resulting in a truncated and functionless DNAAF4 protein.Immunofluorescence analysis indicated that the inner dynein arm was not present in the sperm flagellum,and sperm morphological analysis revealed small sperm with twisted and curved flagella or lacking flagella.The current study found novel biallelic variants causing PCD and asthenoteratozoospermia,extending the range of DNAAF4 pathogenic variants in PCD and associated with the etiology of asthenoteratozoospermia.These findings will improve our understanding of the etiology of PCD.

The application of intraoperative neurophysiological monitoring in selective dorsal neurotomy for primary premature ejaculation:a prospective single-center study

Selective dorsal neurotomy(SDN)is a surgical treatment for primary premature ejaculation(PE),but there is still no standard surgical procedure for selecting the branches of the dorsal penile nerves to be removed.We performed this study to explore the value of intraoperative neurophysiological monitoring(IONM)of the penile sensory-evoked potential(PSEP)for standard surgical procedures in SDN.One hundred and twenty primary PE patients undergoing SDN were selected as the PE group and 120 non-PE patients were selected as the normal group.The PSEP was monitored and compared between the two groups under both natural and general anesthesia(GA)states.In addition,patients in the PE group were randomly divided into the IONM group and the non-IONM group.During SDN surgery,PSEP parameters of the IONM group were recorded and analyzed.The differences in PE-related outcome measurements between the perioperative period and 3 months'postoperation were compared for the PE patients,and the differences in effectiveness and complications between the IONM group and the non-IONM group were compared.The results showed that the average latency of the PSEP in the PE group was shorter than that in the normal group under both natural and GA states(P<0.001).Three months after surgery,the significant effective rates in the IONM and non-IONM groups were 63.6%and 34.0%,respectively(P<0.01),and the difference in complications between the two groups was significant(P<0.05).IONM might be useful in improving the short-term therapeutic effectiveness and reducing the complications of SDN.

Effects of abnormal zona pellucida on fertilization and pregnancy in IVF/ICSI-ET

Objective To analyze the fertilization rate, embryo development and clinical outcome of oocytes with abnormal zona pellucida after in vitro fertilization （IVF） or intracytoplasmic sperm injection （1CS1）. Methods A retrospective analysis included a total of 43 cycles （27 IVF cycles and 16 ICSI cycles） in which oocytes displaying abnormal zona pellucida were retrieved between January 2006 and December 2011. The fertilization rate, embryo quality, and the cumulative clinical pregnancy rate were analyzed. Results Rescue ICSI was applied in 2 7 IVF cycles in which failed extrusion of the second polar body after conventional IVF was observed, and of them, complete failure to fertilize occurred in 23 IVF cycles. The fertilization rate and the normal fertilization rate for IVF （64.83% and 59.32%, respectively） were significantly lower than those for ICS1 （85.19% and 79.01%, respectively）, whereas the cleavage rate （94.12%） with IVF did not differ significantly from that with ICSI （95.65%, P〉0. 05）. The percentages of good-quality embryos in 1VF group （52. 67%） and 1CSl group （43.75%） also did not differ significantly （P〉0.05）. Although the rates of implantation and pregnancy appeared to be greater in IVF group （33.33% and 40.00%, respectively） compared with those in ICSI group （25.00% and 35. 71%, respectively）, the differences were not significant （P〉0.05）.Conclusions ICSI should be carried out for oocytes with abnormal zona pellucida, for which the risk of lVF failure is high. Rescue ICSI improves the likelihood of fertilization of oocytes with abnormal zona pellucida, but cannot improve the clinical outcome.

Effect of the P1 Medium and the ECM Medium on Embryo Quality in IVF

Objective To investigate the effect of the glucose-free preimplantation stage one （P1） medium and the ECM medium on embryo development quality in IVF. Methods The patients with ≥4 zygotes of 2PN were studied. A total of 201 retrieval cycles were included in a prospective randomized study. Each patient was herself control. Half of zygotes of 2PN were transferred into ECM medium （group A） and half into P1 medium （group B）for further culture. Embryo development was evaluated on the day of embryo transfer. The efficacy of ECM was compared with P1 as culture medium for the development of preimplantation embryos. Results No statistically significant differences were noted between the two groups regarding embryo-cleavage rate （97.13% vs 97.55%） and rate of normal-cleaving embryos （58.29% and 58.37%）. The rate of top-quality embryos was statistically higher in group A than in group B （27.59% vs 19.75%, P〈O.05）. Embryo quality, as assessed by morphological parameters （the amount of detached anuclear fragments 〉30%）, was better in group A than in group B （19.86% vs 21.75%）, however, there was no statistically significance. Both the rate of good-quality embryos （47.95% vs 46.17%） and available embryos （63.22% vs 61.19%） were higher in group A than in group B, but there was also no statistically significance. Conclusion The ECM medium may be associated with a better embryo quality compared with the P1 medium.

Modulation of SIRT1 expression improves erectile function in aged rats

Silent information regulator 2-related enzyme 1(SIRT1)is an aging-related protein activated with aging.Herein,we evaluated the role of SIRT1 in aging-related erectile dysfunction.The expression of SIRT1 was modulated in aged Sprague-Dawley rats following intragastric administration of resveratrol(Res;5 mg kg^(-1)),niacinamide(NAM;500 mg kg^(-1))or Res(5 mg kg^(-1))+tadalafil(Tad;phosphodiesterase-5[PDE5]inhibitor;5 mg kg^(-1))for 8 weeks.Then,we determined erectile function by the ratio of intracavernosal pressure(IcP)/mean systemic arterial pressure(MAP).Cavernosal tissues were extracted to evaluate histological changes,cell apoptosis,nitric oxide(NO)/cyclic guanosine monophosphate(cGMP),the superoxide dismutase(SOD)/3,4-methylenedioxyamphetamine(MDA)level,and the expression of SIRT1,p53,and forkhead box O3(FOX03a)using immunohistochemistry,terminal deoxynucleotidyl transferase(TdT)-mediated 2'-deoxyuridine 5'-triphosphate(dUTP)nick-end labeling(TUNEL),enzyme-linked immunosorbent assays,and western blot analysis.Compared with the control,Res treatment significantly improved erectile function,reflected by an increased content of smooth muscle and endothelium,NO/cGMP and SOD activity,and reduced cell apoptosis and MDA levels.The effect of Res was improved by adding Tad.In addition,the protein expression of SIRT1 was increased in the Res group,accompanied by decreased p53 and FOxO3a levels.In addition,inhibition of SIRT1 by NAM treatment resulted in adverse results compared with Res treatment.SIRT1 activation ameliorated aging-related erectile dysfunction,supporting the potential of SIRT1 as a target for erectile dysfunction treatment.