Evaluation of the impedance tonometers TGDc-01 and iCare according to the international ocular tonometer standards ISO 8612

BACKGROUND: Two new tonometers have been introduced that are based on the impedance principle. Both the TGDc-01 (transpalpebral measurement) and the iCare (corneal measurement) do not require corneal anaesthesia. The present work presents an evaluation of both devices. METHODS: Comparative measurements using one of the new tonometers and applanation tonometry were performed by one investigator according to the international standard for ocular tonometer (ISO 8612). Measurements were performed on 445 eyes without corneal pathology from 243 patients. Six measurements were performed for iCare and 3 for TGDc, immediately followed by 3 applanation tonometry measurements. RESULTS: The correlation coefficient with respect to applanation tonometry was 0.81 for TGDc and 0.95 for iCare. TGDc-01 measurements showed an average deviation of 3.1 +/- 2.6 mmHg to those of Perkins applanation tonometry. The maximum difference was 28.7 mmHg below and 9.8 mmHg above the results of applanation tonometry. iCare showed an average deviation of 2.5 +/- 1.1 mmHg to Goldmann tonometry. The maximum difference was 14.5 mmHg below and 9.8 mmHg above. CONCLUSIONS: The results of both new tonometers showed a good correlation with the reference applanation tonometric methods, but the strict requirements of ISO 8612 are not fulfilled by either tonometer at present. Additionally, transpalpebral measurements with the TGDc-01 showed unacceptably high variability.     

切线时间常数在慢性阻塞性肺疾病及肺心病患者F-V曲线形状转变中的变化及临床意义

目的　探讨切线时间常数 ( τt)在慢性阻塞性肺疾病 ( COPD,慢阻肺 )和肺心病患者 F- V曲线形状转变中的变化及临床意义。方法　测定了 90例缓解期 COPD患者 (慢支 43例 ,肺气肿 47例 )及 31例合并肺心病患者的 F- V曲线。并在 F- V曲线上测量高、中、低肺容积的切线时间常数 τt75 、τt5 0 、τt2 5 ,与正常人和吸烟者的 τt作对比分析。结果　 1正常范围内 F- V曲线形状呈平台型、直线型、凸型和凹型 4种 ,| τt75 | >1s或 <1s,τt2 5 <1s,τt关系呈“青少年式”或“老年式”;2轻、中度异常的 F- V曲线呈凸型 ,| τt75 | <1s,τt2 5 ≈ 1s或 >1s,τt 关系呈“喇叭式”改变 ;3严重异常的 F- V曲线形状呈双曲线型 ,| τt75 | <1s,τt2 5 =4s～ 10 s,τt关系呈“塔式”改变。结论　双曲线型、τt2 5 极度延长和“塔式”改变是判断病情严重性的三大重要标志。该方法简便准确 ,利于在临床推广应用     

后路凸侧椎板楔形截骨经肋椎关节松解胸椎间隙治疗青少年重度脊柱侧后凸

【摘要】 目的：评价经后路凸侧椎板楔形截骨经肋椎关节松解胸椎间隙矫形治疗青少年重度脊柱侧后凸畸形的安全性和早期临床效果。方法：2014年5月~2016年12月对我院15例青少年重度脊柱侧后凸患者行经后路凸侧椎板楔形截骨经肋椎关节松解胸椎间隙手术治疗,术前仅1例严重脊柱侧后凸患者行头盆环牵引。男6例,女9例,年龄13～18岁（16.1±1.6岁）。其中先天性脊柱侧后凸3例,特发性11例,神经纤维瘤病性1例。术前侧凸Cobb角82°～144°（102.5°±17.6°）,侧凸的柔韧性为6.4％～28.5％[（21.56±5.70）%];后凸50°～95°（68.1°±15.3°）,冠状位躯干偏移距离（C7中垂线与骶骨中垂线距离）2.0～6.8cm（3.40±1.37cm）。术前四肢肌力及感觉均正常。观察治疗效果。结果：椎板楔形截骨5.20±0.56个（4~6个）,松解椎间隙5.20±0.56个（4~6个）,手术时间6.1～7.9h（7.00±0.51h）,术中出血量1050～2500ml（1450.0±521.3ml）。术后侧凸Cobb角18°～40°（28.0°±6.6°）,矫正率72.5%;后凸22°～42°（27.8°±6.1°）,矫正率58.4%;冠状位躯干偏移距离0～2cm（0.85±0.74cm）,矫正率72.8%。随访25～41个月（33.1±5.4个月）。末次随访时侧凸Cobb角19°～43°（30.0°±6.9°）,矫正率70.6%;后凸22°～42°（28.6°±6.5°）,矫正率57.2%;冠状位躯干偏移距离0.2～2.3cm（1.10±0.72cm）,矫正率71.3%。无胸膜破裂,无假关节形成,无内固定断裂及松动,矫正度无显著丢失。1例患者术前骨盆牵引发生钉道感染,经局部换药及抗生素应用,2周后感染控制;1例术后第3天发生十二指肠系膜上动脉综合征,采取禁食水、持续胃肠减压、维持水电解质平衡、左侧卧位,术后2周痊愈;1例T4左侧椎弓根螺钉侵入椎管压迫神经,术后5h发生左下肢不完全性瘫痪,术后8h去除T4左侧椎弓根螺钉,术后5个月左下肢功能完全恢复。结论：采用后路凸侧椎板楔形截骨经肋椎关节松解胸椎间隙治疗青少年重度脊柱侧后凸畸形,不需要剥离椎体侧方胸膜,手术解剖层次表浅和创伤小,不仅有助于增加脊柱柔韧性,而且可提供足够的压缩和闭合空间来矫正脊柱侧后凸,能获得良好的脊柱三维矫正。     

A ventral approach to stereotaxy of the guinea pig brain

For skeletal muscles, a well-known match exists between the properties of motoneurones and those of their muscle fibres. Hence, the intramuscular distribution of different kinds of motoneuronal nerve endings (e.g. ‘slow’ versus ‘fast’) can be mapped by determining the distribution of the corresponding types of muscle fibre. As a background for further studies of motoneuronal plasticity, we needed precise measures of such distributions. Simple quantitative methods were developed for defining the position and extent of sub-populations of cells within a structure (e.g. the regional distribution of slow versus fast muscle fibres within a muscle cross-section): (a) The ‘mass vector method’ defined the relative position of the target cell cloud. A line was drawn between the calculated centre of mass for the target cells and that for the whole structure. The direction (a1) and length (a2) of this line gave a measure of the direction and degree of target cell eccentricity within the structure. (b) The ‘sector method’ delineated the region containing the target fibres. A circle around the centre of mass for the target fibres was subdivided into a number of equal sectors (standard setting: 20). The most remote point was found within each sector and a line joining these points defined the region of the target fibres. When applied to the ‘slow’ type I fibres of cross-sections from rat hindlimb muscles, the regional area estimates obtained by the sector method were highly correlated with, but 10% lower than those achieved by the well-established ‘convex hull’ method. Highly significant inter-muscular differences were observed for each one of the three new parameters described in this paper (a1, a2, b).     

Impact of corneal parameters on intraocular pressure measurements in different tonometry methods

AIM: To evaluate the impact of central corneal thickness (CCT) and corneal curvature on intraocular pressure (IOP) measurements performed by three different tonometers. METHODS: IOP in 132 healthy eyes of 66 participants was measured using three different tonometry techniques: Goldmann applanation tonometer (GAT), Pascal dynamic contour tonometer (DCT), and ICare rebound tonometer (RT). CCT and corneal curvature were assessed. RESULTS: In healthy eyes, DCT presents significantly higher values of IOP than GAT (17.34±3.69 and 15.27±4.06 mm Hg, P<0.0001). RT measurements are significantly lower than GAT (13.56±4.33 mm Hg, P<0.0001). Compared with GAT, DCT presented on average 2.51 mm Hg higher values in eyes with CCT<600 μm and 0.99 mm Hg higher results in eyes with CCT≥600 μm. The RT results were lower on average by 1.61 and 1.95 mm Hg than those obtained by GAT, respectively. Positive correlations between CCT in eyes with CCT<600 μm were detected for all IOP measurement techniques, whereas a similar relationship was not observed in eyes with thicker corneas. A correlation between IOP values and keratometry in the group with CCT<600 μm was not detected with any of the tonometry methods. In thicker corneas, a positive correlation was found for GAT and mean keratometry values (R=0.369, P=0.005). CONCLUSION: The same method should always be chosen for routine IOP control, and measurements obtained by different methods cannot be compared. All analysed tonometry methods are dependent on CCT; thus, CCT should be taken into consideration for both diagnostics and monitoring.     

Neural network for solving convex quadratic bilevel programming problems

In this paper, using the idea of successive approximation, we propose a neural network to solve convex quadratic bilevel programming problems (CQBPPs), which is modeled by a nonautonomous differential inclusion. Different from the existing neural network for CQBPP, the model has the least number of state variables and simple structure. Based on the theory of nonsmooth analysis, differential inclusions and Lyapunov-like method, the limit equilibrium points sequence of the proposed neural networks can approximately converge to an optimal solution of CQBPP under certain conditions. Finally, simulation results on two numerical examples and the portfolio selection problem show the effectiveness and performance of the proposed neural network.     

Icare回弹式眼压计的应用与护理

目的探讨Icare回弹式眼压计的临床应用以及测量时的护理。方法选取受试者112人112只眼,使用Icare回弹式眼压计分别对患者右眼角膜中央、距角膜缘2mill的0～180。子午线颞侧和鼻侧进行测量。结果Icare回弹式眼压计测得的眼压值在角膜中央、颞侧和鼻侧分别为（15．4±3．4）,（15．8±3．6）,（15．6±3．4）mmHg,角膜中央眼压和水平子午线的鼻侧、颞侧眼压数值比较差异无统计学意义（F=0．325,P〉0．05）,有显著的一致性。结论在正常眼压范围内,Icare回弹式眼压计在角膜中央、颞侧和鼻侧有明显的一致性。测量时的护理是取得准确测量结果的有效保证。     

CHI: A contemporaneous health index for degenerative disease monitoring using longitudinal measurements

In this paper, we develop a novel formulation for contemporaneous patient risk monitoring by exploiting the emerging data-rich environment in many healthcare applications, where an abundance of longitudinal data that reflect the degeneration of the health condition can be continuously collected. Our objective, and the developed formulation, is fundamentally different from many existing risk score models for different healthcare applications, which mostly focus on predicting the likelihood of a certain outcome at a pre-specified time. Rather, our formulation translates multivariate longitudinal measurements into a contemporaneous health index (CHI) that captures patient condition changes over the course of progression. Another significant feature of our formulation is that, CHI can be estimated with or without label information, different from other risk score models strictly based on supervised learning. To develop this formulation, we focus on the degenerative disease conditions, for which we could utilize the monotonic progression characteristic (either towards disease or recovery) to learn CHI. Such a domain knowledge leads us to a novel learning formulation, and on top of that, we further generalize this formulation with a capacity to incorporate label information if available. We further develop algorithms to mitigate the challenges associated with the nonsmooth convex optimization problem by first identifying its dual reformulation as a constrained smooth optimization problem, and then, using the block coordinate descent algorithm to iteratively solve the optimization with a derived efficient projection at each iteration. Extensive numerical studies are performed on both synthetic datasets and real-world applications on Alzheimer’s disease and Surgical Site Infection, which demonstrate the utility and efficacy of the proposed method on degenerative conditions that include a wide range of applications.     

A survey of some recent applications of optimal transport methods to econometrics

This paper surveys recent applications of methods from the theory of optimal transport to econometric problems.