镍铬合金涂覆有机金浆后金基界面的研究

研究认为,任何用于牙科的合金材料从戴入口中开始便不断有金属离子析出,牙科合金的离子析出源于材料的化学腐蚀和电化学腐蚀[1]。镍铬合金在口腔中的耐腐蚀性差,一旦发生腐蚀就可导致不同程度的影响,因此,有必要对铸造合金表面进行改性处理,以提高材料的耐腐蚀性。表面处理的方法有很多,如电镀、化学镀、离子溅射等,通过在一种金属表面涂覆另一种金属,能改善基体金属的理化性能[2]。本研究尝试将有机金浆涂于镍铬合金表面,运用电子探针微分析仪观察界面显微分析涂覆有机金浆前后不同烧结温度的金膜变化,为表面涂层材料、表面性能分析提供实…     

不同材料嵌体与牙体间的边缘适合性研究

目的对铸瓷嵌体、硬质复合树脂嵌体、金合金嵌体、镍铬合金嵌体、银汞合金的边缘适合性进行研究对比,为临床应用提供参考。方法选取25颗成人新鲜离体磨牙,制备标准Ⅱ类洞型,随机分成5组,分别制作铸瓷嵌体、硬质复合树脂嵌体、金合金嵌体、镍铬合金嵌体、直接法银汞充填。随后对所有样本作冷热循环及染色,并作片切,对染色深度作测量,结果应用秩和检验的统计学方法进行处理。结果IPS EmpressⅡ热压铸瓷嵌体组边缘染色深度值最小,银汞合金直接充填组边缘染色深度值最大。铸瓷嵌体组、硬质复合树脂嵌体组及金合金嵌体组分别与镍铬合金组、银汞合金组的边缘染色深度值相比,差异有显著性。结论IPS EmpressⅡ铸瓷嵌体和Brillant硬质复合树脂嵌体的边缘适合性与金合金嵌体接近,优于镍铬合金嵌体与银汞合金直接充填。     

一种牙科喷磨试验仪的设计与应用

目的:牙科喷磨试验仪以测定牙科材料的耐磨性及其应用。方法:该仪由支架、分液漏斗、流砂管、气压表、喷嘴等部件组成牙科喷磨试验仪,用喷磨试验法测量牙科材料耐磨性。结果:用喷磨试验法测量材料耐磨性,各项参数稳定,易于控制,观察指标精确,误差小。并成功测量牙科镍铬合金表面金泥涂层的耐磨性。结论:该喷磨试验仪,为牙科材料涂层及镀层材料耐磨性的测量提供了一种新的可行的方法。     

金泥用于镍铬烤瓷牙的金瓷结合强度及界面电镜观察

目的:观察用金泥涂布镍铬合金基底表面对其金瓷结合强度的影响。方法:用电子探针观察涂布金泥后的金瓷界面,并通过剪切强度测定金瓷结合强度。结果:发现金泥-金属间界面光滑无间隙,提示二者间主要为化学结合;金泥- 瓷层间则存在大量的机械锁结。金泥中可见散在微气泡。涂布金泥组的金瓷结合强度低于未涂布金泥组,两组测量值间有显著性差异。结论:本实验条件下涂布金泥使金瓷结合强度降低。     

PET人工韧带材料纳米化对骨髓基质干细胞粘附、增殖及分化影响的实验研究

目的:观察人骨髓基质干细胞(human bone marrow mesenchymal stem cells,hBMSCs)在经过表面纳米化处理的PET人工韧带材料表面的粘附、增殖及成骨分化。方法:根据PET膜片表面处理情况分为PET组(PET膜片未经表面处理)、LBL组(PET膜片表面经透明质酸、壳聚糖纳米自组装涂层处理)和HA组(PET膜片经透明质酸、壳聚糖纳米自组装处理后,表面再加纳米羟基磷灰石涂层)3组。在上述3种PET材料上分别培养hBMSCs后进行各项检测。扫描电镜(SEM)观察hBMSCs在材料上培养1天和7天时的细胞形态。培养7天后,Alamar blue法检测hBMSCs的增殖,pNPP法检测碱性磷酸酶(ALP)活性。RealTimePCR检测培养3天hBMSCs的整合素β1mRNA表达。结果:SEM显示HA组和LBL组hBMSCs能更好地伸展和粘附,形态明显优于PET组。培养7天,HA组和LBL组的细胞增殖、ALP活性定量均显著高于PET组(P<0.001);HA组细胞增殖显著高于LBL组(P=0.01),HA组ALP活性显著高于LBL组(P<0.001)。培养3天后,HA组和LBL组hBMSCs的整合素β1mRNA表达显著高于PET组(P<0.001),HA组显著高于LBL组(P=0.003)。结论:PET人工韧带材料表面经壳聚糖、透明质酸纳米自组装涂层和纳米羟基磷灰石涂层处理后,能明显促进人hBMSCs的粘附、增殖和分化。纳米羟基磷灰石涂层的作用最明显。     

C／C复合材料表面聚多巴胺涂层的制备及性能研究

目的：碳／碳（ C／C）复合材料为当前极具潜力的骨修复生物材料,在其表面制备聚多巴胺涂层旨在改善C／C复合材料亲水性和生物活性。方法制备一系列不同涂覆时间、涂覆环境（空气或富氧）条件的C／C复合材料表面聚多巴胺涂层,采用水接触角测试、扫描电子显微镜、能谱分析、原子力显微镜及蛋白吸附等表征手段探索不同制备条件对各项性能的影响规律,得出较佳制备条件。结果反应条件为多巴胺浓度2．0 g／L,涂覆时间30 min（氧气）＋11．5 h（空气）时,聚多巴胺涂层水接触角由空白对照组的64．0°下降至25．9°,其亲水性得到极大的改善;通过扫描电子显微镜、能谱分析及原子力显微镜测试得出该涂层均匀且致密;同时蛋白吸附含量为0．2817 mg。结论在C／C复合材料表面制备了聚多巴胺涂层,极大地改善了C／C复合材料的亲水性和生物活性。这一结果提示聚多巴胺涂层的C／C复合材料可作为新一代骨组织修复材料,为后续医学应用提供了理论依据。     

固定义齿修复材料对MRI图像的影响探讨

目的 研究分析不同的固定义齿修复材料对MRI的影响,为其临床应用和研究提供有效的理论支持.方法 研究于2013年1月～ 2014年5月结束,入选对象为该阶段在接受治疗的110例口腔疾病行头颈部MRI检查的患者,研究以当前临床口腔固定修复治疗中常用的非贵金属和责金属为实验材料,分析MRI图像上的伪像发生规律以及对检查结果的影响情况.结果 经研究显示镍铬合金产生的伪影面积相对较大,镍的含量差异对伪影范围的大小起到主要的影响作用,而金合金几乎不会对MRI产生较大的伪像影响.结论 镍合金固定义齿修复材料对MRI的成像情况具有明显的影响,而金合金对其产生的影响不大,口腔内固定的修复体对头颈部MRI检查无影响.     

金自组膜固定生物分子技术在核酸及免疫传感器中的应用

本综述了金表面自组装技术固定生物分子的方法及其在核酸传感器和免疫传感器中的应用。包括金表面自组装技术的原理；金硫键的形成；金电极及金膜的沉积制作技术：热蒸发沉积、电子束蒸发沉积、飞溅沉积等；金表面Piranha溶液的清洁与处理；自组装常用试剂：含巯基或二硫键的化合物；金自组膜单层的取向度特性、针眼对固定生物分子的影响；自组膜活泼尾基的活化方法及偶联生物分子的方法；金自组装技术在核酸传感器及免疫传感器中固定核酸、蛋白质的应用，包括在电化学、表面等离子体共振、石英微天平、光学波导测定等核酸与免疫传感器中的应用。     

Fe_3O_4涂层多巴胺修饰PET人工韧带对MC3T3-E1细胞粘附、增殖和分化影响的实验研究

目的:观察MC3T3-E1细胞在Fe_3O_4涂层多巴胺修饰聚对苯二甲酸乙二醇酯(PET)人工韧带材料表面的粘附、增殖及成骨分化情况。方法:按PET材料表面涂层情况分为4组:PET组,即PET表面未处理组;多巴胺(DA)组,即PET表面进行多巴胺涂层组;100 Fe_3O_4组和200 Fe_3O_4组,分别为PET经多巴胺处理后表面涂有100μg/ml和200μg/ml的Fe_3O_4溶液组。在上述4组PET材料上分别培养MC3T3-E1细胞,进行各项检测。扫描电镜(SEM)和X射线能谱分析(EDS)材料涂层情况。细胞在材料上培养3天和7天后行荧光染色,观察细胞粘附情况。培养1、3、7天后,行CCK-8检测MC3T3-E1细胞的增殖。诱导培养基培养7天检测碱性磷酸酶活性;培养21天行茜素红染色,检测细胞矿化情况;培养14天行Real Time PCR检测骨钙蛋白和胶原I基因的表达。结果:SEM和EDS检测验证涂层成功。荧光染色显示涂层组有效增加了细胞的粘附。细胞增殖实验示涂层组对细胞增殖有促进作用,各涂层组与未涂层组差异具有统计学意义(P<0.05)。涂层材料组碱性磷酸酶OD值明显高于未涂层组(P<0.05)。茜素红染色示各组都有较多矿化结节形成,定量分析显示100 Fe_3O_4组和200 Fe_3O_4组与PET组比较差异有统计学意义(P<0.05)。PCR检测显示涂层组骨钙蛋白和I型胶原基因的表达都较未涂层组增加,骨钙蛋白:Fe_3O_4组与PET组比较差异有统计学意义(P<0.01);I型胶原:DA组、Fe_3O_4组与PET组比较差异具有统计学意义(P<0.05)。结论:经多巴胺修饰四氧化三铁涂层处理的PET人工韧带材料,能明显促进MC3T3-E1细胞的粘附、增殖和分化。     

液相沉积纳米二氧化硅涂层对纯钛耐腐蚀性的影响

目的在体外模拟口腔环境下,研究液相沉积法制备的纳米二氧化硅(SiO2)涂层对纯钛耐腐蚀性能的影响。方法将16个纯钛试件随机分为对照组、0.1 mol/L硅酸钠溶液组、0.3 mol/L硅酸钠溶液组、0.5 mol/L硅酸钠溶液组。用液相沉积法在实验组纯钛试件表面制备SiO2涂层,用动电位极化曲线法考察各组试件在人工唾液中的腐蚀电位及腐蚀电流密度,同时用X线衍射、能谱分析、扫描电镜等分析涂层表面成分及形貌。结果涂层为非晶态SiO2。各实验组较对照组显著提高了纯钛腐蚀电位,降低了腐蚀电流密度(P<0.05)。0.3 mol/L硅酸钠溶液组耐腐蚀性最好。结论液相沉积法制备的纳米SiO2涂层可提高纯钛在人工唾液中的耐腐蚀性能,硅酸钠溶液的最佳浓度是0.3 mol/L。     

不同种类贵金属合金与镍铬合金的金瓷结合强度分析

目的：比较3种贵金属合金和镍铬合金与瓷的金瓷结合强度。方法：通过金瓷界面间的剪切强度测定，观察金铂合金、金钯合金、银钯合金及镍铬合金的金瓷结合强度。结果：不同种类的贵金属合金及镍铬合金间的金瓷结合强度测量值均有差异，镍铬合金的结合强度值最高，金铂次之，银钯再次之，金钯最小。除金—铂合金组与银—钯合金组之间无显著性差异外，其他各组之间都有显著性差异。结论：在本实验条件下贵金属合金结合强度低于镍铬合金，其中金钯合金最低。     

Creatine supplementation--part II: in vivo magnetic resonance spectroscopy

PURPOSE: Our purpose was to study effects of creatine (Cr) supplementation on muscle metabolites noninvasively by means of magnetic resonance spectroscopy (MRS) before and after supplementation with Cr or placebo. METHODS: 1H-MRS was used in a comprehensive, double-blind, cross-over study in 10 volunteers to measure Cr in m. tibialis anterior and m. rectus femoris at rest. PCr/ATP was observed in m. quadriceps femoris by 31P-MRS at rest and after exercise. RESULTS: A significant increase in total Cr was observed with Cr intake in m. tibialis anterior (+9.6 +/- 1.7%, P = 0.001) and in m. rectus femoris (+18.0 +/- 1.8%, P < 0.001). PCr/ATP showed a significant increase (+23.9 +/- 2.3%, P < 0.001) in m. quadriceps femoris at rest with Cr supplementation. Post-Cr supplementation recovery rates from exercise were significantly lower (k = 0.029 s(-1), P < 0.01) compared with postplacebo consumption (k = 0.034 s(-1)) and presupplementation (k = 0.037 s(-1)). However, higher levels of PCr/ATP at rest compensate for this reduction of the recovery rate after Cr supplementation. The increase of PCr/ATP determined by 31P-MRS correlates with the increase of Cr observed by 1H-MRS (r = 0.824, P < 0.001). CONCLUSION: Noninvasive observation of Cr and PCr after Cr supplementation shows an increase in a muscle specific manner. Higher preexercise levels of PCr/ATP at rest compensate for significantly slower recovery rates of PCr/ATP after Cr supplementation.     

Colloidal gold nanoparticles as a blood-pool contrast agent for X-ray computed tomography in mice

OBJECTIVES: To present the pharmacokinetics and computed tomographic imaging efficacy of colloidal gold nanoparticles (AuNPs) as a blood-pool agent for x-ray computed tomography (CT). METHODS AND MATERIALS: To prepare the colloidal AuNPs, gold nanocrystals were modified using sulfhydrated polyethylene glycol (PEG). Cytotoxicity and histopathologic tests were carried out for toxicity evaluation. Six adult Balb/c mice underwent microcomputed tomography scans after injection of colloidal AuNPs (2.5 micromol Au/g body weight). Four mice with HT-1080 tumors were imaged for visualization of the tumor vasculature. RESULTS: The PEG coated colloidal AuNPs appeared as spherical nanoparticles with 38-nm diameters. The AuNPs-PEG showed a biocompatibility without toxicity in the mice. We identified a stable imaging window for visualizing the vasculature system, immediately to 24 hours after injection. Microcomputed tomography imaging using AuNPs-PEG clearly visualized the tumor vascular structures. CONCLUSION: Colloidal AuNPs show potential as a blood-pool agent for x-ray CT imaging.     

Effects of oral creatine and resistance training on myosin heavy chain expression

PURPOSE: This study examined 12 wk of creatine (Cr) supplementation and heavy resistance training on muscle strength and myosin heavy chain (MHC) isoform mRNA and protein expression. METHODS: Twenty-two untrained male subjects were randomly assigned to either a control (CON), placebo (PLC), or Cr (CRT) group in a double-blind fashion. Muscle biopsies were obtained before and after 12 wk of heavy resistance training. PLC and CRT trained thrice weekly using three sets of 6-8 repetitions at 85-90% 1-RM on the leg press, knee extension, and knee curl exercises. CRT ingested 6 g.d-1 of Cr for 12 wk, whereas PLC consumed the equal concentration of placebo. RESULTS: There were no significant differences for percent body fat (P > 0.05). However, for total body mass, fat-free mass, thigh volume, muscle strength, and myofibrillar protein, CRT and PLC exhibited significant increases after training when compared to CON (P < 0.05), whereas CRT was also significantly greater than PLC (P < 0.05). For Type I, IIa, and IIx MHC mRNA expression, CRT was significantly greater than CON and PLC, whereas PLC was greater than CON (P < 0.05). For MHC protein expression, CRT was significantly greater than CON and PLC for Type I and IIx (P < 0.05) but was equal to PLC for IIa. CONCLUSION: Long-term Cr supplementation increases muscle strength and size, possibly as a result of increased MHC synthesis.     

Creatine supplementation affects muscle creatine during energy restriction

INTRODUCTION: Anaerobic performance and body protein may decrease with energy restriction practiced by some athletes for weight loss. METHODS: This investigation examined the effects of creatine (Cr) supplementation during energy restriction on muscle Cr, exercise performance (10 sprints of 6 s, with 30-s rest), nitrogen balance, and body composition in male resistance trainers. Creatine supplemented (CrS, 20 g x d(-1) of Cr) and those given a placebo (P1) consumed a formula diet of 75.3 kJ (18 kcal) x kg(-1) x d(-1) (54.7% C, 21.3% P, 24% F) for 4 d. A control group was unsupplemented and continued their normal diet. There were no changes in body composition or performance of the control group. RESULTS: CrS and P1 demonstrated similar decreases in body weight and percent body fat. The percent change in fat-free mass was more for P1 (2.4+/-0.3% reduction) than CrS (1.4+/-0.4%), but urinary nitrogen losses were similar. Significant increases in muscle total Cr and CrP of 15-16% were demonstrated by CrS over the energy restriction period, whereas P1 had no changes in muscle Cr. Total work done during the sprints expressed per body weight tended to be 3.8% higher in CrS and 0.5% less in P1 after the energy restriction (P = 0.058). CONCLUSION: It was concluded that Cr supplementation increased muscle Cr during short-term energy restriction but did not affect body fat or protein loss. The change in muscle creatine was reflected in a tendency for higher total sprint work for the Cr group.     

Energy expenditure of submaximal running does not increase after cycle-run transition

AIM: This study was performed to determine the relationship between increased fat oxidation and decreased running efficiency following intense cycling exercise. METHODS: Twenty-two middle-level triathletes were studied during submaximal running before and after submaximal cycling exercise. All subjects completed a 13-min run on a track at a velocity corresponding to 75% of their maximal aerobic speed (MAS) before (T1) and after (T2) submaximal cycling exercise at 75 % of maximal aerobic power (MAP). The energy cost of running (Cr) was quantified using the O(2) uptake (.VO(2)) and energy expenditure (EE) using the respiratory exchange ratio (RER). Gas exchange was measured over 30 s during the 3(rd) min and last 30 s of each run. RESULTS: The results show that after cardiorespiratory equilibration (12 min 30 s), Cr (calculated in mL(O(2))*kg(-1)*m(-1)) during T2 was higher than during T1 (+ 8.2+/-4.3%; P = 0.03). Similar observations were made for .VO(2) (+ 8.2+/-4.3%; P = 0.03) and pulmonary ventilation (+ 7.0+/-12.3%; P = 0.04). RER decreased between T1 and T2 (- 8.6+/-9.2 %; p = 0.01). EE and Cr expressed in kJ.kg(-1).m(-1) did not vary significantly between T1 and T2. CONCLUSION: We suggest that the decrease in RER drop may be a result of greater lipid oxidation as metabolic substrate after cycling exercise.     

Effects of resistance exercise and creatine supplementation on myasthenia gravis: a case study

PURPOSE: The purpose of this case study was to determine the effects of 15 wk of resistance exercise and creatine (Cr) supplementation on body composition, training volume, peak strength, and complete blood chemistry in a patient with myasthenia gravis (MG). METHODS: The patient was a 26-yr-old man who was taking prednisone and azathioprine for his condition. The patient self-administered 5 g of Cr per day in addition to resistance exercise 3 times per week. Fasting blood samples were obtained and body weight (BW) and fat free mass (FFM; via hydrostatic weighing) were measured before and after training and Cr supplementation. In addition, isokinetic (Cybex II) peak strength for leg extension (LE), leg flexion (LF), and volume load (repetition x mass lifted) for the first and last resistance training session were determined. RESULTS: After Cr supplementation and training, the results demonstrated increases in BW (6.8%), FFM (4.3%), upper body volume load (37.0%), lower body volume load (15.0%), and peak strength for LE (37.0%) and LF (12.5%). Moreover, blood chemistry values remained within normal limits for the duration of the 15-wk study. CONCLUSION: These data suggest that resistance exercise plus Cr supplementation may promote gains in strength and FFM in patients with MG.     

Effects of supplement timing and resistance exercise on skeletal muscle hypertrophy

PURPOSE: Some studies report greater muscle hypertrophy during resistance exercise (RE) training from supplement timing (i.e., the strategic consumption of protein and carbohydrate before and/or after each workout). However, no studies have examined whether this strategy provides greater muscle hypertrophy or strength development compared with supplementation at other times during the day. The purpose of this study was to examine the effects of supplement timing compared with supplementation in the hours not close to the workout on muscle-fiber hypertrophy, strength, and body composition during a 10-wk RE program. METHODS: In a single-blind, randomized protocol, resistance-trained males were matched for strength and placed into one of two groups; the PRE-POST group consumed a supplement (1 g x kg(-1) body weight) containing protein/creatine/glucose immediately before and after RE. The MOR-EVE group consumed the same dose of the same supplement in the morning and late evening. All assessments were completed the week before and after 10 wk of structured, supervised RE training. Assessments included strength (1RM, three exercises), body composition (DEXA), and vastus lateralis muscle biopsies for determination of muscle fiber type (I, IIa, IIx), cross-sectional area (CSA), contractile protein, creatine (Cr), and glycogen content. RESULTS: PRE-POST demonstrated a greater (P < 0.05) increase in lean body mass and 1RM strength in two of three assessments. The changes in body composition were supported by a greater (P < 0.05) increase in CSA of the type II fibers and contractile protein content. PRE-POST supplementation also resulted in higher muscle Cr and glycogen values after the training program (P < 0.05). CONCLUSION: Supplement timing represents a simple but effective strategy that enhances the adaptations desired from RE-training.     

Esophageal mucoceles complicating double exclusion of the esophagus after ingestion of caustics

A mucocele is rarely observed after esophageal exclusion for corrosive burns. It may represent a contra-indication to esophageal conservation in case of a total gastric resection for necrosis and perforation of the stomach. To evaluate this risk, 15 patients, operated between January 1970 and december 1988, were reviewed: they underwent total gastric resection with esophageal exclusion, followed by a secondary colon transplant between the cervical esophagus and the duodenum. A plain chest film was performed for 13 patients and a CT scan for 11 patients. Mean follow-up was 5.7 years (2 months - 17 years). Four patients died, one of them after resection of a compressive esophageal mucocele. Six mucoceles were detected on 13 chest films and 7 were described on 11 CT scans. On the whole, 8 mucoceles were diagnosed on 15 patients; one of them was complicated by tracheal compression. The formation of a secondary esophageal mucocele is a late sign of incomplete destruction of the esophageal wall. It is a frequent complication of esophageal exclusion performed after total gastrectomy for corrosive burns of the stomach. It must be detected on a chest film which shows the largest dilatations or on a CT scan, which is a better investigation. When the diameter of the mucocele is equal of superior to 50 mm, it can be compressive and must be treated by resection of internal diversion.     

Effects of oral creatine and resistance training on myogenic regulatory factor expression

PURPOSE: This study examined 12 wk of creatine (Cr) supplementation and heavy resistance training on skeletal muscle creatine kinase (M-CK) mRNA expression and the mRNA and protein expression of the myogenic regulatory factors Myo-D, myogenin, MFR-4, and Myf5. METHODS: Twenty-two untrained males were randomly assigned to either a control (CON), placebo (PLC), or Cr (CRT) group in a double-blind fashion. Muscle biopsies were obtained before and after training. PLC and CRT trained thrice weekly using 3 sets of 6-8 repetitions at 85-90% 1-RM on the leg press, knee extension, and knee curl exercises. CRT ingested 6 g.d-1 of Cr for 12 wk while PLC consumed the equal amount of placebo. RESULTS: After training, M-CK mRNA expression, as well as myogenin and MRF-4 mRNA and protein expression, were found to be significantly greater for CRT compared with PLC and CON, whereas PLC was also significantly different from CON (P < 0.05). For Myo-D mRNA and protein, both CRT and PLC were significantly different from CON (P < 0.05), but CRT and PLC were not different from one another. No significant differences were located for Myf5 mRNA or protein (P > 0.05). M-CK mRNA was correlated with myogenin (r = 0.916) and MRF-4 (r = 0.883) protein (P < 0.05). CONCLUSION: When combined with heavy resistance training, Cr supplementation increases M-CK mRNA expression, likely due to concomitant increases in the expression of myogenin and MRF-4. Therefore, increases in myogenin and MRF-4 mRNA and protein may play a role in increasing myosin heavy chain expression, already shown to occur with Cr supplementation.