Bonding performance and interfacial characteristics of short fiber‐reinforced resin composite in comparison with other composite restoratives

The purpose of this study was to investigate the shear bond strength (SBS) and surface free‐energy (SFE) of short fiber‐reinforced resin composite (SFRC), using different adhesive systems, in comparison with other composite restoratives. The resin composites used were everX Posterior (EP), Clearfil AP‐X (CA), and Filtek Supreme Ultra Universal Restorative (FS). The adhesive systems used were Scotchbond Multi‐Purpose (SM), Clearfil SE Bond (CS), and G‐Premio Bond (GB). Resin composite was bonded to dentin, and SBS was determined after 24 h of storage in distilled water and after 10,000 thermal cycles (TCs). The SFEs of the resin composites and the adhesives were determined by measuring the contact angles of three test liquids. The SFE values and SFE characteristics were not influenced by the type of resin composite, but were influenced by the type of adhesive system. The results of this study suggest that the bonding performance and interfacial characteristics of SFRC are the same as for other composite restoratives, but that these parameters are affected by the type of adhesive system. The bonding performance of SFRC was enhanced by thermal cycling in a manner similar to that for other composite restoratives.     

Key changes in denervated muscles and their impact on regeneration and reinnervation

The neuromuscular junction becomes progressively less receptive to regenerating axons if nerve repair is delayed for a long period of time. It is difficult to ascertain the denervated muscle＇s residual receptivity by time alone. Other sensitive markers that closely correlate with the extent of denervation should be found. After a denervated muscle develops a fibrillation potential, muscle fiber conduction velocity, muscle fiber diameter, muscle wet weight, and maximal isometric force all decrease; remodeling increases neuromuscular junction fragmentation and plantar area, and expression of myogenesis-related genes is initially up-regulated and then down-regulated. All these changes correlate with both the time course and degree of denervation. The nature and time course of these denervation changes in muscle are reviewed from the literature to explore their roles in assessing both the degree of detrimental changes and the potential success of a nerve repair. Fibrillation potential amplitude, muscle fiber conduction velocity, muscle fiber diameter, mRNA expression levels of myogenic regulatory factors and nicotinic acetylcholine receptor could all reflect the severity and length of denervation and the receptiveness of denervated muscle to regenerating axons, which could possibly offer an important clue for surgical choices and predict the outcomes of delayed nerve repair.     

A Novel Diagnostic Test for End-Stage Sensory Failure Associated With Diabetic Foot Ulceration: Proof-of-Principle Study

Background:Diabetic foot ulceration (DFU) affects only a subgroup of patients with diabetic neuropathy, that is, those with pain-insensitivity due to end-stage sensory failure. Pain perception failure develops insidiously and remains asymptomatic until first DFU. As loss of pain perception is clinically significant, timely detection is mandatory.Objectives:A novel suprathreshold pinprick pain stimulus of 512 mN force made from optical glass-fiber was explored in a prospective cross-sectional diagnostic accuracy study to detect DFU-related end-stage sensory failure.Methods:A total of 116 participants were studied (25 healthy people, 22 patients with diabetes without relevant complications, 19 patients with previous painful foot or leg injuries, and 50 patients with previous or active painless DFU [reference standard]). Palmar and plantar surfaces were stimulated in a standardized fashion. At the feet, the second and third toe skinfolds and the middle of the plantar arch were stimulated. Participants scored stimulated pricking discomfort or pain intensity 0 to 10 on a numerical rating scale.Results:At hands, intensity was rated on average 5 (1-10) [median (range)] by 114/116 participants. Per foot, participants without DFU scored 5 (1-10), while those with DFU scored 0 (0-3) (P < .0001). At plantar toe skinfolds, the absence of pinprick pain perception detected DFU-associated sensory failure with an accuracy of 99.5% (sensitivity 99.5%, specificity 99.4%, positive likelihood ratio 248, and negative likelihood ratio 0.005).Conclusion:In this pilot study, nociceptive stimulation of a plantar toe skinfold with a 512 mN optical glass-fiber pinprick accurately identified DFU-associated end-stage sensory failure.     

Wear Behavior of Fiber Laser Textured TiN Coatings in a Heavy Loaded Sliding Regime

In heavy loaded mating components, such as sliders and sliding bearings, guaranteeing the efficiency of lubricant films for long times during severe service conditions is very complicated. In this work, the benefits deriving from the use of fiber laser sources for surface texturing of very thin TiN coatings in severe wear working conditions were demonstrated. Evaluations of the laser textured dimples shape, geometry and density are given. Wear performance of the fiber laser textured surfaces was evaluated in discontinuous oil lubricated conditions with a flat contact. High normal load and low sliding speed were applied. Comparison tests were also performed on commercial TiN and WC/C coatings. In terms of average wear volume and maximum wear depth, Laser Surface Texturing of TiN provided respectively a 70% and a 45% reduction if compared to plain TiN. If compared to WC/C the wear resistance gains were lower but LST TiN maintained such benefits for longer wear runs. SEM analysis also revealed that the laser interaction provided a localized thermal cracking to the TiN coating. However, the sliding action caused very limited and localized coating fragmentation or delamination.     

Treatment of tumors involving the optic nerves and chiasm

An approach toward treatment of tumors involving the optic apparatus is presented. When tumors cause mass effect, microsurgical excision or debulking is generally recommended. Radiosurgery has been controversial yet advances in imaging and high speed computer planning allow treatment of lesions involving the optic apparatus with low morbidity. Microsurgical and radiosurgical approaches to tumors involving the globe, orbit, suprasellar region and third ventricle are discussed. Gamma Knife radiosurgery for choroidal melanomas spares orbital excenteration. We have used a marginal dose of 20–25 Gy for choroidal melanomas and generally limit the optic nerves and chiasm to less than 10 Gy in other cases. The effective dose for cavernous hemangiomas remains unclear, however we have had success with marginal doses in the range of 16–20Gy. Lower doses may prove successful yet better spare vision in cases where vision is useful. Our combined microsurgical and radiosurgical approach to tumors involving the apparatus has had an excellent rate of sparing vision, a low overall morbidity and excellent success.     

Assessing impact of differential symptom functioning on post‐traumatic stress disorder (PTSD) diagnosis

This article explores the generalizability of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM‐IV) diagnostic criteria for post‐traumatic stress disorder (PTSD) to various subpopulations. Besides identifying the differential symptom functioning (also referred to as differential item functioning [DIF]) related to various background variables such as gender, marital status and educational level, this study emphasizes the importance of evaluating the impact of DIF on population inferences as made in health surveys and clinical trials, and on the diagnosis of individual patients. Using a sample from the National Comorbidity Study‐Replication (NCS‐R), four symptoms for gender, one symptom for marital status, and three symptoms for educational level were significantly flagged as DIF, but their impact on diagnosis was fairly small. We conclude that the DSM‐IV diagnostic criteria for PTSD do not produce substantially biased results in the investigated subpopulations, and there should be few reservations regarding their use. Further, although the impact of DIF (i.e. the influence of differential symptom functioning on diagnostic results) was found to be quite small in the current study, we recommend that diagnosticians always perform a DIF analysis of various subpopulations using the methodology presented here to ensure the diagnostic criteria is valid in their own studies. Copyright © 2014 John Wiley & Sons, Ltd.     

猪降主动脉环向力学性质的实验研究

目的研究猪降主动脉的力学特性。方法猪降主动脉按照距心脏距离分成5组,各组由左右两侧组织、腹侧面组织构成。使用单轴拉伸方法拉伸组织,获得应力与伸张比曲线。采用经典数学模型分析5个部位(位置1～5)弹性、胶原纤维模量以及胶原纤维激活参数等特征,并对比腹侧面与两侧组织之间的力学差异。结果在环向上,胶原纤维模量随着远离心脏的方向逐渐增长,而弹性纤维模量位置1～4随着距心脏的距离增加而逐渐增大,位置5的弹性纤维模量减小,且位置5两侧的环向弹性纤维模量小于腹侧面约19%;在轴向上,弹性纤维模量小于腹侧面约37%,位置5腹侧面的弹性纤维模量相比于位置4差异不大(均值差异约5%)。在整个降主动脉中,侧面环向胶原纤维模量大于腹侧面约26%,环向弹性纤维模量在靠近心脏的四部分侧面高于腹侧面约16%。结论猪胸主动脉的环向力学特性和位置有关,最远端的部分在低应力下表现出较软特点。研究结果有助于科研人员更好理解主动脉的力学特征以及开展更细致的计算机建模。