冷却条件对2219-T62铝合金厚板搅拌摩擦焊接头耐蚀性的影响

通过开路电位(OCP)、动电位极化曲线、扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究水冷和空冷对20 mm厚2219-T62铝合金搅拌摩擦焊(FSW)接头在3.5%NaCl溶液中耐蚀性的影响。结果表明,与2219铝合金母材和FSW焊缝热影响区相比,具有较高电位、较低腐蚀电流密度和细小均匀沉淀强化相的2219铝合金FSW焊缝焊核区,在3.5%NaCl溶液中具有较好的耐蚀性。与空冷接头相比,水冷FSW接头的耐蚀性明显提高。通过显微组织形貌分析可知,2219铝合金FSW接头在含氯离子腐蚀溶液中的耐蚀性取决于电位的高低和第二相粒子尺寸和分布。

TC4/TA15异种钛合金激光焊焊缝的显微组织和高温力学性能

研究不同焊接工艺参数条件下TC4/TA15异种钛合金激光焊接接头的显微组织和高温力学性能。结果表明:TC4/TA15异种激光焊焊缝熔合区由含针状α’马氏体的粗化β柱状晶组成,热影响区主要由初始α相和β转变相组成,TA15侧热影响区的宽度窄于TC4侧热影响区的宽度。TC4/TA15异种接头的屈服强度和抗拉强度随温度的升高而降低,高温拉伸强度从高到低的顺序为TA15母材>异种接头>TC4母材,800°C时塑性变形程度最高。TC4/TA15异种接头横截面的最高显微硬度位于焊缝中心,热处理后接头的显微硬度整体降低,但硬度分布特征未发生改变。异种接头的高温拉伸断裂均发生在TC4母材侧,并在拉伸过程中发生明显颈缩,微观断口呈现韧性断裂特征。

TC4/TA15异质钛合金激光焊焊缝的显微组织和力学性能（英文）

研究TC4/TA15异质钛合金激光焊焊缝的显微组织和力学性能。结果表明:TC4/TA15异质钛合金激光焊缝熔合区显微组织由针状α相和马氏体α′组成,TC4侧热影响区主要是残余α相和马氏体α′,TA15侧热影响区则出现了大量等轴α相。焊缝显微硬度呈现不对称特征,熔合区最高,TA15母材区最低。随应变速率由1×10^(-4) s^(-1)增加到1×10^(-2) s^(-1),接头屈服强度和抗拉强度均升高,且满足TC4母材>TC4/TC4同质接头>TA15母材>TA15/TA15同质接头>TC4/TA15异质接头,而硬化能力和应变硬化指数则降低。不同应变速率下拉伸TC4/TA15异质接头均在TA15母材断裂,断口呈现韧性断裂特征。

Pneumothorax during retroperitoneal laparoscopic partial nephrectomy in a lupus nephritis patient:A case report

BACKGROUND Downgrading target treatment and laparoscopic partial nephrectomy have become increasingly popular in patients with renal cell carcinomas.Rare as it is,pneumothorax is one of the most severe intraoperative complications which needs immediate recognition.On the other hand,as a rheumatological disease,lupus nephritis requires a long period of hormone therapy.Cases of pneumothorax in hormone-consuming renal cancer patients are even fewer.CASE SUMMARY A 39-year-old woman was admitted to our department to take a laparoscopic partial nephrectomy.The patient had a medical history of lupus nephritis and renal clear cell carcinoma with hormone and target treatment.Her blood oxygen saturation dropped to 92%during the operation,and pneumothorax was detected by ultrasound.O2 inhalation and lung dilation were performed.Her vital signs were monitored closely throughout the operation.The operation was accomplished,and she regained consciousness smoothly.A postoperative bedside chest X-ray was conducted after she was transferred to the urosurgery ward,while no evidence of further pneumothorax or lib injury was observed.CONCLUSION Pneumothorax is a severe complication in laparoscopic or robotic-assisted laparoscopic operations,especially in retroperitoneal ones.It is easily neglected unless the injury of the diaphragm is found.Low insufflation pressure and shorter operation time are necessary for patients with a history of long-term hormone consumption or chronic immune system disease.

Targeted isolation of antitubercular cycloheptapeptides and an unusual pyrroloindoline-containing new analog,asperpyrroindotide A,using LC–MS/MS-based molecular networking

Further insights on the secondary metabolites of a soft coral-derived fungus Aspergillus versicolor under the guidance of MS/MS-based molecular networking led to the isolation of seven known cycloheptapeptides,namely,asperversiamides A–C(1–3)and asperheptatides A–D(4–7)and an unusual pyrroloindoline-containing new cycloheptapeptide,asperpyrroindotide A(8).The structure of 8 was elucidated by comprehensive spectroscopic data analysis,and its absolute configuration was determined by advanced Marfey’s method.The semisynthetic transformation of 1 into 8 was successfully achieved and the reaction conditions were optimized.Additionally,a series of new derivatives(10−19)of asperversiamide A(1)was semi-synthesized and their anti-tubercular activities were evaluated against Mycobacterium tuberculosis H37Ra.The preliminary structure−activity relationships revealed that the serine hydroxy groups and the tryptophan residue are important to the activity.

Modulation of Anti-Oxidation Ability by Proanthocyanidins during Germination of Arabidopsis thaliana Seeds

作为结束， flavonoid biosynthetic 小径的产品主要在种子上衣中积累的 Proanthocyanidins (舞步) 但是他们的生物功能大部分是未知的。我们在 Arabidopsis 的舞步缺乏的异种在外部地应用的氧化压力下面在种子上衣和萌芽变化中学习了反氧化能力。舞步缺乏的变异的种子的萌芽比的快，建议萌芽的导致舞步的抑制在低或不氧化的应力下面野类型。当应用氧化压力高时，舞步缺乏的异种的萌芽比的低，建议舞步相关的反氧化的损失在异种的野类型的能力。用表明异种的骆驼毛的织物，我们的研究两个都表明了那骆驼毛的织物发信号小径和舞步是重要的让反应在种子萌芽期间服务氧化应力。然而，在到氧化应力的 abi 异种和舞步异种之间的反应的差异建议骆驼毛的织物发信号小径不能在减轻氧化应力在舞步行动起一个主要作用。在低或不氧化的应力下面，萌芽被 ABA 内容主要在种子决定，舞步缺乏的变异的种子由于他们的更低的骆驼毛的织物内容更快发芽了比野类型。然而，当舞步缺乏的种子在高氧化的应力下面发芽了时，氧化损害禁止了萌芽。在高氧化的压力下面的野类型的展出更高的萌芽由于舞步反氧化能力。外部地使用的氧化应力在与舞步生物的续生说基因的表示变化与一致的内长的舞步内容导致了变化。舞步调制了在种子萌芽期间控制了反应的氧种类和反氧化能力的层次的一些关键酶的活动。这个工作建议舞步贡献由在萌芽控制和反氧化反应起双作用在环境压力下面帮助萌芽的适应机制。

Structure modification,antialgal,antiplasmodial,and toxic evaluations of a series of new marine-derived 14-membered resorcylic acid lactone derivatives

Marine natural products play critical roles in the chemical defense of many marine organisms and are essential,reputable sources of successful drug leads.Sixty-seven 14-membered resorcylic acid lactone derivatives 3–27 and 30–71 of the natural product zeaenol(1)isolated from the marine-derived fungus Cochliobolus lunatus were semisynthesized by chlorination,acylation,esterification,and acetalization in one to three steps.The structures of these new derivatives were established by HRESIMS and NMR techniques.All the compounds(1–71)were evaluated for their antialgal and antiplasmodial activities.Among them,14 compounds displayed antifouling activities against adhesion of the fouling diatoms.In particular,9 and 34 exhibited strong and selective inhibitory effects against the diatoms Navicula laevissima and Navicula exigua(EC50=6.67 and 8.55μmol/L),respectively,which were similar in efficacy to those of the positive control SeaNine 211(EC50=2.90 and 9.74μmol/L).More importantly,38,39,and 69–71 showed potent antiplasmodial activities against Plasmodium falciparum with IC50 values ranging from 3.54 to 9.72μmol/L.Very interestingly,the five antiplasmodial derivatives displayed non-toxicity in the cytotoxicity assays and the zebrafish embryos model,thus,representing potential promising antiplasmodial drug agents.The preliminary structure–activity relationships indicated that biphenyl substituent at C-2,acetonide at positions C-5′and C-6′,and tri-or tetra-substituted of acyl groups increased the antiplasmodial activity.Therefore,combining evaluation of chemical ecology with pharmacological models will be implemented as a systematic strategy,not only for environmentally friendly antifoulants but also for structurally novel drugs.

m4C DNA methylation regulates biosynthesis of daptomycin in Streptomyces roseosporus L30

Despite numerous studies on transcriptional level regulation by single genes in drug producing Actinomyces,the global regulation based on epigenetic modification is not well explored.N4-methylcytosine(m4C),an abundant epigenetic marker in Actinomycetes’genome,but its regulatory mechanism remains unclear.In this study,we identify a m4C methyltransferase(SroLm3)in Streptomyces roseosporus L30 and multi-omics studies were performed and revealed SroLm3 as a global regulator of secondary metabolism.Notably,three BGCs inΔsroLm3 strain exhibited decreased expression compared to wild type.In-frame deletion of sroLm3 in S.roseosporus L30 further revealed its role in enhancing daptomycin production.In summary,we characterized a m4C methyltransferase,revealed the function of m4C in secondary metabolism regulation and biosynthesis of red pigment,and mapped a series of novel regulators for daptomycin biosynthesis dominated by m4C methylation.Our research further indicated that m4C DNA methylation may contribute to a metabolic switch from primary to secondary metabolism in Actinomyces.

Preclinical studies of the triazolo[1,5-a]pyrimidine derivative WS-716 as a highly potent,specific and orally active P-glycoprotein(P-gp)inhibitor

Multidrug resistance(MDR) is the main cause of clinical treatment failure and poor prognosis in cancer. Targeting P-glycoprotein(P-gp) has been regarded as an effective strategy to overcome MDR. In this work, we reported our preclinical studies of the triazolo[1,5-a]pyrimidine-based compound WS-716 as a highly potent, specific, and orally active P-gp inhibitor. Through direct binding to P-gp,WS-716 inhibited efflux function of P-gp and specifically reversed P-gp-mediated MDR to paclitaxel(PTX) in multiple resistant cell lines, without changing its expression or subcellular localization. WS-716 and PTX synergistically inhibited formation of colony and 3D spheroid, induced apoptosis and cell cycle arrest at G2/M phase in resistant SW620/Ad300 cells. In addition, WS-716 displayed minimal effect on the drug-metabolizing enzyme cytochrome P4503A4(CYP3A4). Importantly, WS-716 increased sensitivity of both pre-clinically and clinically derived MDR tumors to PTX in vivo with the T/C value of 29.7% in patient-derived xenograft(PDX) models. Relative to PTX treatment alone, combination of WS-716 and PTX caused no obvious adverse reactions. Taken together, our preclinical studies revealed therapeutic promise of WS-716 against MDR cancer, the promising data warrant its further development for cancer therapy.