Cell viability after osteotomy and bone harvesting: comparison of piezoelectric surgery and conventional bur

The aim of this study was to evaluate and compare the influence of a piezoelectric device versus a conventional bur on osteocyte viability and osteoblast and osteoclast activity using an in vivo mouse model. Osteotomies were created and bone grafts were harvested using either a conventional bur or a piezoelectric device; the resulting injuries and bone grafts were evaluated over an extended time-course using molecular and cellular assays for cell death (TUNEL assay), cell viability (4′,6-diamidino-2-phenylindole (DAPI) staining), the onset of mineralization (alkaline phosphatase activity), and bone remodelling (tartrate-resistant acid phosphatase activity). Osteotomies created with a piezoelectric device showed greater osteocyte viability and reduced cell death. Bone grafts harvested with a piezoelectric device exhibited greater short-term cell viability than those harvested with a bur, and exhibited slightly more new bone deposition and bone remodelling. The difference in response of osteocytes, osteoblasts, and osteoclasts to bone cutting via a bur and via a piezoelectric device is negligible in vivo. Given the improved visibility and the margin of safety afforded by a piezoelectric device, they are the instrument of choice when cutting or harvesting bone to preserve soft tissue.     

Study on the Effects of Different Cutting Angles on the End-Milling of Wire and Arc Additive Manufacturing Inconel 718 Workpieces

This research presents an analysis of the effects of different cutting angles on the side milling of Inconel 718 products manufactured with the Wire and Arc Additive Manufacturing (WAAM) technique. Considering that this manufacturing technology can build near-net shape products, its surface quality is deemed unqualified as a final product, requiring a post-processing step. In this paper, three different angles—0°, 35°, and 90—are compared, looking for possible differences regarding its machinability. As the alloy in question is a material known for being difficult to machine, and the samples were produced with the additive manufacturing technique that created peculiar characteristics, it was deemed necessary to analyze different aspects of the machining process: the surface quality, tool wear, and cutting forces for all three cases, and to rank the angles regarding these results. With analog experiments with the same alloy but cold-rolled, it was possible to infer that not only is the 0-degree angle is the best option for milling, but the anisotropy of the WAAM samples could be the major source of the differences in the milling results.     

Method of Data Selection for Turning of Inconel 718 Alloy Obtained by Casting and Laser Sintering Powder

This article focuses on the issues related to the machining of DMLS (Direct Metal Laser Sintering) laser sintered parts made of Inconel 718 alloy. Longitudinal turning with CBN (cubic boron nitride) tool inserts is analyzed. The authors made an attempt to establish a procedure to find the optimal finishing cutting parameters while minimizing the specific cutting force and taking into account the machined surface quality criterion. During experiments the influence of cutting data on the values of cutting force and specific cutting force were performed. Moreover, the results of measurements of surface roughness parameters and the results of analysis of chip form are presented as well. Cast Inconel 718 has also been tested for comparative purposes. The variability of the material’s hardening state during machining was found, as well as the variability of the specific cutting force value as a function of the cross-sectional shape of the cutting layer. The values of all components of the total cutting force for turning the material obtained by the additive method are lower than for turning the cast material by approximately 32%. At the end of the article, the authors present an application of the proposed optimization algorithm. It was established that by changing the cross-section shape of the cutting layer, it was possible to perform the turning process at a specific cutting force value of 22% less, which is achieved by reducing the cross-section size.     

Reduction of Cracks in Marble Appeared at Hydro-Abrasive Jet Cutting Using Taguchi Method

The appearance of cracks in brittle materials in general and in marble, in particular, is a problem in the hydro-abrasive jet cutting process. In this paper is presented a method to reduce the appearance of cracks when cutting with a hydro-abrasive jet of marble by using statistical analysis. The Taguchi method was used, establishing the main parameters that influence the process. Research design was based on performing experiments by modifying the parameters that influence the process. In this way, it has been shown that the stochastic effects resulting from the marble structure can be reduced. A careful study was made of the behavior of marble under the action of the hydro-abrasive jet, and of the behavior of the whole process in the processing of brittle materials. Results of experiments confirmed the hypothesis that statistical analysis is a procedure that can lead to a decrease in the number of cracks in processing. The measurement was performed with precise instruments and analyzed with recognized software and according to the results obtained, the reduction of the number of cracks is achieved through use of low pressure, a minimum stand-off distance and a small tube diameter. In this way, the paper presents a new and effective tool for optimizing the cutting with a hydro-abrasive jet of marble.     

In situ reprogramming to transdifferentiate fibroblasts into cardiomyocytes using adenoviral vectors: Implications for clinical myocardial regeneration

Objective

The reprogramming of cardiac fibroblasts into induced cardiomyocyte-like cells improves ventricular function in myocardial infarction models. Only integrating persistent expression vectors have thus far been used to induce reprogramming, potentially limiting its clinical applicability. We therefore tested the reprogramming potential of nonintegrating, acute expression adenoviral (Ad) vectors.

经尺骨鹰嘴V型截骨入路双侧锁定钢板治疗肱骨髁间粉碎性骨折

目的：探讨经尺骨鹰嘴V型截骨入路双侧锁定钢板固定肱骨髁间粉碎性骨折的疗效.方法：将我院31例采用经尺骨鹰嘴V型截骨入路双侧锁定钢板内固定治疗的肱骨髁间粉碎骨折患者的临床资料进行回顾性分析.结果：31例患者均获得平均12个月的随访,尺骨鹰嘴截骨及肱骨髁间粉碎骨折均获得骨性愈合,无切口感染及异位骨化发生,未见与截骨相关的并发症.术后肘关节功能评价参照Mayo法评分,优17例,良10例,可4例,优良率达87.10％.结论：经尺骨鹰嘴V型截骨入路双锁定钢板内固定治疗肱骨髁间粉碎骨折,可以较好地显露骨折情况,有效地固定骨折,有利于术后早期功能锻炼,恢复关节活动功能.     

严重烧伤行手急诊切痂功能性治疗

目的 :提高手部深度烧伤治疗质量。方法 :将重度以上合并手深度烧伤 85例分为传统治疗组 (A组 )和改良治疗组 (B组 ) ,A组在休克期内只行必要的减压术 ,伤后 3～ 7d行手部切削痂自体皮移植术 (滚轴刀取皮 ) ;B组于伤后 8h内行手部浅层切痂异体皮或生物敷料覆盖术 ,伤后 3～ 5d进行大张自体中厚皮更植(鼓取皮 ) ,指蹼处理上将指蹼缘切开向手背提升 ,以加深指蹼 ,再行皮片插入 ,缝成曲线形 ,创面愈合后各指蹼间隔以条形疤痕贴 ,戴弹力手套并用弹力条布在手套外分指蹼加压 ,晚间应用可塑夹板或行手指牵引对抗疤痕孪缩。结果 :B组在植皮成活率、创面愈合时间等方面优于传统治疗组 ,假蹼发生率下降。结论 :严重烧伤行手部急诊切痂延期植皮为治疗手部深度烧伤较好的方法之一。     

吉林省地区朝鲜族和汉族健康人群LPL基因HindⅢ酶切位点多态性分布的研究

目的分析我国吉林省地区朝鲜族和汉族健康人群脂蛋白酯酶(lipoprotein lipase,LPL)基因HindⅢ酶切位点多态性的分布。方法应用聚合酶链反应(polimerase chain reaction,PCR)等技术检测66例朝鲜族和90例汉族LPL基因多态性,并将其基因型和等位基因在两族人群中的分布进行统计学分析。结果朝鲜族人群LPL基因P+P+基因型,P+P-基因型和P-P-基因型频率分别为57.58%,33.33%和9.09%;汉族人群分别为73.33%,24.44%和2.22%,两组基因型的分布差异具有显著性(P=0.049)。朝鲜族人群P+等位基因和P-等位基因频率分别为74.24%和25.76%;汉族人群分别为85.56%和14.44%,两组等位基因的分布差异具有显著性(P=0.012)。结论 LPL基因HindⅢ酶切位点多态性在中国吉林省地区朝鲜族和汉族人群中的分布差异有显著性。