Machinability Investigation of Nitronic 60 Steel Turning Using SiAlON Ceramic Tools under Different Cooling/Lubrication Conditions

The machining of nickel-based super alloys is challenging, owing to the generation of high cutting temperatures, as well as difficulty in maintaining dimensional accuracy and minimizing surface roughness, which compels the use of cutting fluids for reducing these issues due to efficient cooling/lubrication strategies. The present work investigates the comparative performance of four cooling/lubrication techniques: dry cutting, wet, minimum quantity lubricant (MQL) and compressed-air modes in turning Nitronic 60 steel using a new-generation SiAlON ceramic inserts. Several machinability parameters were analyzed for performance evaluation. For this purpose, 16 cycles of turning trials were performed based on Taguchi’s L₁₆ orthogonal array experimental design by varying cutting conditions and lubrication modes. MQL exhibits beneficial effects as compared to the other lubrication conditions concerning low cutting force, improved surface finish, decreased cutting temperature, longer tool life, and lower white layer thickness on machined surface. Burr formation on the saw-tooth chip surface, as well as friction, greatly influenced the tool flank wear due to improper cooling and poor lubrication approach in dry, wet, and compressed-air-cooled machining environments in comparison to MQL-machining. From an economical perspective, the tool life in MQL machining improved by 11%, 72%, and 138% in the comparison with flooded, compressed-air, and dry conditions, respectively. The results of the study demonstrate that using the MQL system can help with heat extraction capability, and provide some promising outcomes.     

SCID小鼠接种人白血病细胞HL-60的流式细胞术分析

腹腔及静脉注入人白血病细胞HL 6 0建立人白血病异种移植模型 ,采用流式细胞仪检测HL 6 0细胞表面标志CD33、DNA含量及周期分布 ,及病理组织学检查观察其生长特性。结果显示 ,实验接种的HL 6 0细胞在放射线处理或未处理的SCID小鼠体内均能生长 ,发生全身性白血病。 3周时外周血即可见白血病细胞浸润 ,受累肝、脾增生期细胞比例增加 ,iv接种 5× 10 6HL 6 0细胞 ,在发病晚期 ,骨髓细胞中CD33+ 细胞占 3 79%和 2 97% ;ip接种 1 0× 10 7的SCID小鼠 ,其骨髓细胞中CD33+ 率为 12 32 %。提示HL 6 0 /SCID小鼠模型为良好的肿瘤体内研究模型 ,以CD33阳性率判断模型中肿瘤细胞浸润指标能快速、客观地判断病情。     

Infection of undifferentiated and differentiated promyelocytic cells (HL-60) with varicella-zoster virus

HL-60 cells can be induced to differentiate into macrophage-like cells by treatment with 12-O-tetra-decanoylphorbol-13-acetate (TPA). The relationship between virus replication and cell differentiation was investigated using HL-60 cells that had been induced to differentiate by TPA (dHL-60 cells) and undifferentiated cells (udHL-60 cells). On infection of these cells with cell-free varicella-zoster virus (VZV), virus antigens were detected in dHL-60 cells but not in udHL-60 cells, and the percentage of antigen-positive dHL-60 cells increased during incubation. Similar results were obtained by infectious center assay, and the percentage of antigen-positive cells correlated with the stage of cell differentiation. No significant difference was found in the binding of VZV to dHL-60 cells and udHL-60 cells. Furthermore, trypsin treatment after adsorption suggested that VZV penetrated into udHL-60 cells. These findings indicate that VZV may be able to replicate in mature monocytes but may be harbored in immature monocytes in vivo.     

抗缺氧物质灌胃小鼠抗缺氧能力测定和Hsp70的表达

目的:研究抗缺氧物质对小鼠抗缺氧能力的影响及Hsp70的表达。方法:小鼠100只,随机分为塞隆(高原鼢鼠)肌肉组、高海拔牦牛肉组、石榴籽组、红景天组和空白对照组,连续灌胃(ig)10天,于常压下进行抗缺氧实验和Western Blot测定Hsp70的表达。结果:红景天组、石榴籽组、塞隆肉组小鼠密闭缺氧存活时间延长;塞隆肉组、石榴籽组、红景天组灌胃的小鼠的Hsp70表达被诱导出现。结论:抗缺氧物质(即红景天胶囊、石榴籽超临界萃取物、塞隆肉超临界萃取物)灌胃的小鼠密闭缺氧存活时间均延长;抗缺氧物质灌胃的小鼠的Hsp70的表达增强,说明抗缺氧药物可诱导Hsp70的表达,Hsp或许可以作为抗缺氧药物研究和测试指标。     

趋化因子CCL21、 E-selectins、 Hsp90在实验性牙周炎大鼠牙周组织中的表达及意义

目的：探讨趋化因子CCL21、E选择素（E-selectins）、热休克蛋白90(heat shock protein 90,Hsp90)在实验性牙周炎大鼠牙周组织中的表达及意义。方法：选取40只10周龄雄性Wistar大鼠,随机分为4组,每组10只。A、B、C组均建立牙周炎模型,其余10只为空白对照组。A、B、C组分别于牙周基础治疗后4、8、12周处死并取第一、二磨牙间牙周组织进行CCL21、E-selectins、Hsp90 mRNA 和蛋白表达检测。采用SPSS 25.0软件包对数据进行统计学分析。结果：A、B、C组牙周附着水平显著大于对照组（P<0.05）;牙周基础治疗后,牙周附着水平呈先升高后降低趋势,牙周组织中CCL21、E-selectins、Hsp90 mRNA以及蛋白相对表达量呈降低趋势（P<0.05）。结论：CCL21、E-selectins、Hsp90 mRNA在牙周炎组织中表达上调,随着牙周局部治疗,其表达水平逐渐降低。     

Reduced or painful jaw movement after collision-related injuries: a population-based study

BACKGROUND: The authors report the incidence of and factors associated with reduced and/or painful jaw movement after motor vehicle collisions that resulted in whiplash-associated disorders (WADs). METHODS: All adults filing collision-related personal injury claims during an 18-month period in Saskatchewan, Canada, were evaluated via questionnaire to determine demographic characteristics, precollision health (including jaw pain), collision parameters and collision-related symptoms, including reduced and/or painful jaw movement and injury-related neck pain. The authors excluded patients who were hospitalized for more than two days and those who sustained injuries as a pedestrian, bicyclist or motorcyclist. In determining incidence rates, the authors also excluded those who had had jaw pain before the collision. RESULTS: The incidence of reduced and/or painful jaw movement was 14.9 percent (n = 1,158), and it was higher in subjects with WADs (15.8 percent) than in those without WADs (4.7 percent; relative risk = 3.36, 95 percent confidence interval, 2.36 to 4.78). Within the WAD injuries, multivariable logistic regression revealed that the onset of reduced and/or painful jaw movement was associated with female sex; age < 50 years; having hit one's head in the collision; and postinjury symptoms of difficulty swallowing, ringing in the ears, dizziness or unsteadiness, and more intense neck pain. Collision parameters, such as head position at the time of the crash and headrest use and type, were not associated with onset of jaw symptoms. CONCLUSIONS: Reduced or painful jaw movement was more common in people with WADs than in those with other collision-related injuries. Among those with WADs, reduced or painful jaw movement was more common in women and younger people. CLINICAL IMPLICATIONS: Reduced or painful jaw movement is an important aspect of WADs, and more studies are needed to determine how to best assess and treat this problem.     

Identification of 4‐aryl‐1H‐pyrrole[2,3‐b]pyridine derivatives for the development of new B‐Raf inhibitors

During the last years, a significant interest in the identification of new classes of B‐Raf inhibitors has emerged. In this study, which was conceived within an effort that culminated in the recent report of the first dual inhibitors of B‐Raf and Hsp90, we describe the identification of four compounds based on 4‐aryl‐1H‐pyrrole[2,3‐b]pyridine scaffold as interesting starting points for the development of new B‐Raf inhibitors. Structure–activity relationships and predicted binding modes are discussed. Moreover, the novelty of the newly identified structures with respect to currently known B‐Raf inhibitors was assessed through a ligand‐based dissimilarity assessment. Finally, structural modifications with the potential ability to improve the activity toward B‐Raf are put forward.     

台盼蓝拒染法、MTT法、CCK-8法在研究As203细胞毒性作用中的意义

目的筛选三氧化二砷（As203）对HL一60细胞毒性的有效剂量及作用时间的检测方法,并对其结果进行分析。方法采用台盼蓝拒染法、M1Tr法、CCK～8法测定不同浓度的As203,体外作用HL一60细胞株的细胞存活率．采用单因素方差分析其与剂量一时间依赖反应的关系。结果4．0、8．0μmol／L作用48、72h及8．0μmol／L作用24h被染细胞小于5％,其余均未观察到蓝染细胞。MTY法检测在1．0～8．0μmol／LAs20,剂量范围内培养24、48、72h（P〈0．05）,各组均能够抑制HL-60细胞活性。CCK-8法检测在0．5～8．0μmol／LAs203剂量范嗣内培养24、48、72h（P〈0．05）,各组均能够抑制HL-60细胞活性。HL-60细胞在不同时间、不同浓度均能出现细胞存活率明显降低,As20,的毒副作用呈现明显的剂量-时间依赖反应。结论在研究As203的细胞毒性时,用CCK-8法优于M11’法,均比台盼蓝法更为灵敏。