Pseudoxanthoma elasticum-like papillary dermal elastolysis in non-exposed skin

Pseudoxanthoma elasticum-like papillary dermal elastolysis is an acquired elastic tissue disorder clinically similar to pseudoxanthoma elasticum in the absence of systemic involvement. Histopathologically, special staining of elastic fibers demonstrates a total or partial band-like loss of elastic fibers in the papillary dermis. Although ultraviolet radiation seems to be one of the main etiological factors in this entity, we report a case of pseudoxanthoma elasticum-like papillary dermal elastolysis on the neck of a woman who wore hijab.     

Elastic Characteristics of Digital Cores from Longmaxi Shale Using Lattice Spring Models

Effective medium methods for the attribution of micro-structures to macro elastic properties of shales are important for the prediction of sweet spots in the shale-gas production. With X-ray micro-computed tomography (XMCT), the micro-structures of shale core samples from Longmaxi Formation are visualized and characterized by 3D digital images. As an efficient alternative to conventional effective medium methods for estimating elastic properties, we propose a consistent workflow of lattice spring modeling (LSM) to emulate the digital cores using three types of lattices. Particular attention is paid to investigate the effective Young's moduli, Poisson's ratios, and preferred orientations, by uniaxial compression tests along two directions. Within elastic deformation, the impact of lattice arrangements on the anisotropy is even more than those of stress disturbances and micro-structural features. Compared with analytical approximations and theoretical predictions, the LSM numerical scheme shows general applicability for heterogeneous porous rocks.     

弹力绷带与医用棉两种衬垫在电动气压止血带中的应用比较

目的通过比较医用棉纸与弹力绷带作为电动气压止血带衬垫的方法,观察不同衬垫材料在电动气压止血带中的应用效果。方法将2018年1月至12月镇江市中西医结合医院骨科收治的100例患者采用随机数字表分为弹力绷带组(50例)和棉纸组(50例),分别采用弹力绷带和医用棉纸作为电动气压止血带衬垫材料,观察比较两组的止血效果、皮肤损伤发生率以及对电动气压止血带袖带的保护情况。结果弹力绷带组患者的皮肤压痕、瘀斑、水泡等皮肤损伤发生率低于棉纸组,差异有统计学意义(P<0.05);两组止血效果比较差异无统计学意义;弹力绷带组的袖带污染发生率(4%)明显少于棉纸组(16%),差异有统计学意义(P<0.05)。结论弹力绷带作为止血带衬垫材料止血效果明显,而且能有效降低患者受压处皮肤的损伤率,同时减少了止血带袖带的污染,有利于袖带的清洁消毒。     

Transmission and scanning electron microscopy of cutis rhomboidalis

Cutis rhomboidalis nuchae was assessed in a 65-year-old patient. Optical microscopy showed basophilic agglomerations in the reticular dermis with decreased elastic fibers. Transmission electron microscopy showed elongated, curved and fragmented structures, and in their interior the presence of electron-dense lumps was reduced and irregular, similar to modified elastic fibers, whereas the collagen fibers had a normal aspect. Scanning electron microscopy showed deposits between the bundles of collagen, resembling pebbles or stones. These findings demonstrate that, at one stage of the disease, the collagen remains normal and the alterations are seen in the elastic tissue.     

双侧耳郭软骨骨化1例并文献复习

目的探讨耳郭软骨骨化的发病机制、临床表现、诊断依据、鉴别诊断、治疗方法。方法回顾性分析1例耳郭软骨骨化患者的临床资料并复习相关文献进行总结。结果耳郭软骨骨化的发病机制暂不明确,通常无明显不适症状,少数患者可伴有局部疼痛、听力下降等症状。颞骨CT可辅助诊断,最终确诊依赖于组织病理检查。症状不明显时可暂予观察,若症状严重影响了生活和工作,可予手术治疗。结论耳郭软骨骨化在临床上较为少见,目前尚无有效逆转耳郭骨化的办法。积极寻找病因,及早干预,有利于避免病情进一步发展。     

Prediction of structural failure of tibial bone models under physiological loads: Effect of CT density–modulus relationships

Although finite element (FE) models can provide distinct benefits in understanding knee biomechanics, in particular the response of the knee to implants, their usefulness is limited by the modelling assumptions and input parameters. This study highlights the uncertainty of material input parameters derived from the literature and its limitation on the accuracy and usefulness of FE models of the tibia. An FE model of the intact human knee and a database of knee forces (muscles, ligaments and medial and lateral tibio-femoral contacts) were developed for walking and stair-descent activities. Ten models were constructed from ten different combinations of apparent bone density to elastic modulus material property relationships, published in the literature. Some of the published material property relationships led to predictions of bone strains in the proximal tibia which exceeded published failure criteria under loads imposed by normal activities. These relationships appear not to be applicable for the human tibia. There is a large discrepancy in proposed relationships that cover the cancellous bone density range. For FE models of the human tibia, the material relationship proposed by Morgan et al., which assumed species and anatomic site dependence, produced the most believable results for cancellous bone. In addition to casting doubt on the use of some of the published density–modulus relationships for analysis of the human proximal tibia, this study highlights the need for further experimental work to characterise the behaviour of bone with intermediate densities.     

观察弹性髓内钉在儿童四肢长骨骨折中的治疗效果

目的对弹性髓内钉在儿童四肢长骨骨折中的治疗效果进行观察。方法资料选自2011年11月~2012年11月我院收治的四肢长骨骨折患儿92例,通过弹性髓内钉对患儿进行治疗。结果所有患儿的治疗效果评价中优良率为96.74%,说明弹性髓内钉治疗儿童四肢长骨骨折的效果较好。结论采用弹性髓内钉对四肢长骨骨患儿进行治疗的效果较好。     

小儿股骨干骨折弹性髓内钉固定对骨质愈合的影响

目的探究小儿股骨干骨折弹性髓内钉固定对骨质愈合的影响。方法选取2012年5月至2013年2月期间因股骨干骨折而在我院进行治疗的54例患儿作为本次研究对象。对患儿股骨干骨折采取弹性髓内钉进行固定。统计患儿手术时间、术中出血量、术后并发症及下地完全负重时间,根据Flynn功能预后评价表对患儿进行预后评价。结果患儿手术时间为35.50~78.40 min,平均(50.45±10.32)min,出血量32.20~48.60 mL,平均(40.37±8.36)mL。54例患儿术后均得到随访,平均随访时间为10~18个月,术后未发生延迟愈合、生长畸形、骨折不愈合、髓内钉感染、拔钉困难等并发症;早期有3例患儿因钉尾折弯发生轻度的"激惹"反应,导致轻度疼痛,后期采取不弯折钉尾且留取恰当长度后,"激惹"反应消失。根据Flynn功能预后评价表对患儿进行预后评价:优50例,良4例,优良率100%。下地完全负重时间为5.0~16.0周,平均为(11.2±3.5)周。结论弹性髓内钉适用于小儿股骨干骨折治疗,具有小切口微创、术后功能优良率高、并发症少等优点,值得临床推广与应用。     

Influence of occlusal hypofunction on the elastic property and bone formation of rat alveolar bone

The purpose of this study was to investigate the influence of occlusal hypofunction on the maintenance of the elastic property and alveolar bone formation using an occlusal hypofunction model. Analyses of the elastic property and bone formation of the alveolar bone were carried out by the compression test and the bone histomorphometry in the two directions (the tooth axis direction and the bucco-lingual direction). The compression test was done with the texturometer to analyse the springiness of bone specimens of the mandibular first molar. Bone histomorphometric analyses were evaluated using double labeled frontal section. Results showed that occlusal hypofunction significantly reduced the springiness and suppressed the alveolar bone formation in the bucco-lingual direction. These results suggested that occlusal function plays an important role in maintenance of the elastic property and bone formation of the alveolar bone.     

Can poly(acrylic) acid molecular weight mixtures improve the compressive fracture strength and elastic modulus of a glass-ionomer restorative?

Objectives

To optimize the compressive fracture strength (σ) and elastic modulus (E) of a glass-ionomer (GI) restorative using poly(acrylic) acid (PAA) weight average molecular weight (M_w) mixtures.

Methods

174 PAA solutions were prepared (four control PAA M_ws at three PAA concentrations (25, 35 and 45%) (n = 12) and six M_w mixtures (Groups A-F at nine blend ratios and three PAA concentrations (n = 162))). The viscosity (η) of each PAA solution was determined using a digital viscometer. The PAA solutions were hand-mixed with a commercial GI restorative powder (Ionofil Molar; Voco, Cuxhaven, Germany) and σ and E were determined using cylindrical (6 mm height, 4 mm diameter) specimens (n = 20) at 24 h. Data were analyzed using analyses of variance (ANOVA) (three-, two- and one-way) and regression analyses at p < 0.05.

Results

The three- and two-way ANOVAs highlighted significant effects of M_w mixture, blend ratio and PAA concentration (all p < 0.0001) on the η, σ and E data. Regression analyses showed significant increases in η, σ and E (p < 0.0001) with increasing M_w from Groups A to F. There was no significant effect of blend ratio on the σ data for Groups A (p = 0.178), D (p = 0.747) and F (p = 0.107) and on the E data (p > 0.083).

Significance

The current approach to improving the mechanical properties of GI restoratives using PAA M_w mixtures is encouraging, however, further manipulation of the GI restorative system by optimizing PAA M_w mixtures, blend ratios and PAA concentrations is required to elicit further improvements in σ and E without impacting upon the η of the PAA solution.