Enhanced T-ray signal classification using wavelet preprocessing

This study demonstrates the application of one-dimensional discrete wavelet transforms in the classification of T-ray pulsed signals. Fast Fourier transforms (FFTs) are used as a feature extraction tool and a Mahalanobis distance classifier is employed for classification. Soft threshold wavelet shrinkage de-noising is used and plays an important role in de-noising and reconstruction of T-ray pulsed signals. An iterative algorithm is applied to obtain three optimal frequency components and to achieve preferred classification performance.     

The principal–agent problem and owner‐managers: An instrumental variables application to nursing home quality

The literature on provider ownership has primarily focused broadly on for‐profits compared with nonprofits and chains versus nonchains. However, the understanding of more nuanced ownership arrangements within individual facilities is limited. Utilizing the principal–agent and managerial control frameworks, we study the role of managerial ownership and its relationship to quality among for‐profit nursing homes (NHs). We identify NH administrators with more than 5% ownership (owner‐manager) from Ohio Medicaid Cost Reports (2005–2010) and link these data to long‐stay resident records in the Minimum Data Set. Using differential distance to the nearest NHs with a salaried manager relative to an owner‐manager, we address the differential selection into these two types of NHs. After instrumenting for admissions to owner‐managed NHs, quality among long‐stay residents at owner‐managed NHs is generally better than NHs with salaried managers. We find suggestive evidence that the magnitudes of quality difference are larger when the principal–agent problem is likely more pronounced, such as when NHs that are part of a multifacility chain and located in more concentrated markets.     

稳心颗粒联合尼可地尔治疗缺血性心肌病合并房性心律失常患者的效果

目的:观察稳心颗粒联合尼可地尔治疗缺血性心肌病合并房性心律失常患者的效果。方法:选取103例缺血性心肌病合并房性心律失常患者作为研究对象,以电脑随机数字表法将其分为研究组51例和对照组52例。两组均开展常规基础治疗,在此基础上,对照组采用尼可地尔治疗,研究组在对照组基础上联合稳心颗粒治疗,比较两组治疗前后心功能指标[左室舒张末期内径(LVEDD)、左室收缩末期内径(LVESD)、左室射血分数(LVEF)]水平、P波最大时限、P波离散度、6 min步行试验(6MWT)距离和不良反应发生率。结果:治疗后,研究组LVEDD和LVESD水平均低于对照组,LVEF水平高于对照组,6MWT距离长于对照组,差异有统计学意义(P<0.05);治疗后,研究组P波最大时限和P波离散度均小于对照组,差异有统计学意义(P<0.05);两组不良反应发生率比较,差异无统计学意义(P>0.05)。结论:稳心颗粒联合尼可地尔治疗缺血性心肌病合并房性心律失常患者可改善心功能指标水平,延长6MWT距离,减小P波最大时限和P波离散度,效果优于单纯尼可地尔治疗。     

Distance traveled to undergo revision shoulder arthroplasty is impacted by patient demographics and exceeds that of primary shoulder arthroplasty

BackgroundPrevious research has highlighted disparities in access to and outcomes following shoulder arthroplasty. The purpose of this study is to compare travel distance for primary vs. revision surgery and to determine the relationships between travel distance to undergo revision shoulder arthroplasty and patient demographics and postoperative adverse outcomes. We hypothesized that older patients, those with increased medical comorbidities, and those with greater financial resources would travel farther for surgery.MethodsThe Healthcare Cost and Utilization Project, American Hospital Association, and UnitedStatesZipCodes.org Enterprise data sets were compiled to collect data on patient demographics, operation performed, and postoperative adverse outcomes. Population-weighted zip code centroid points of patients’ residences as well as hospital coordinates were used to approximate the distance traveled to undergo shoulder arthroplasty. Kruskal-Wallis tests and logistic regression analyses were used to analyze the relationship between travel distance and patients’ demographics and postoperative outcomes.ResultsPatients traveled farther to undergo revision shoulder arthroplasty than to undergo primary shoulder arthroplasty (P = .0001). Among patients who underwent revision operations, older age (P = .0001) and increased medical comorbidities (P = .003) were associated with decreased travel distance. White patients and those with commercial insurance traveled farther to receive care (P = .0001). There were no clinically significant associations between postoperative outcomes following revision surgery and travel distance.ConclusionPatients may travel farther to undergo revision surgery owing to patient preferences or because these complex operations are performed at fewer centers. Younger and healthier patients, white patients, and those with commercial insurance plans traveled farther to receive care. Future work is needed to determine the underlying causes of these disparities and whether it is patient preferences or systemic factors such as hospital density or access to high-quality health insurance that are influencing access to this specialized surgical care.     

Length Matters: Short Base-Plate Angle Guides May Lead to Guide-Wire Mal-Positioning When Inserting a DHS. A Radiographic Modeling Study

The dynamic hip screw (DHS) consists of a barrel-plate fixed to the relatively-straight proximal femoral shaft, and a screw which slides within the barrel at a fixed angle, usually 135°. The guide-wire is inserted using a guide at the set angle. Guide design varies between manufacturers, with some new guides being particularly short. We analysed the impact of guide design on the resulting trajectory of the guidewire, and its potential to cause a surgical error. Twenty AP hip radiographs were analysed. Trauma Cad (Brainlab, Munich, Germany) software was used to template a 4-hole 135° DHS onto the intact femur with the screw positioned in the center of the head. A template of a Stryker (Michigan, USA) 135° DHS guide (37 mm long) was then overlaid at the hip screw entry point, and the set trajectory marked. The divergence between the two trajectories was measured (α angle). The distance the guide would have to be moved inferiorly to attain the correct position in the head was then noted. The median divergence (α angle) caused by the guide relative to the ideal position was 6° (range 2–12). This led to the guidewire placement being a median of 9.1 mm (range 3–23) superior in the head (β).To achieve the correct position of the wire in the head, the guide needed to be moved inferiorly a median of 8 mm (range 2–10). © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:574–577, 2020     

糖尿病患者白内障术后视功能与术前HbA1c值的相关性研究

目的:探究糖尿病患者白内障术后黄斑区视网膜结构、脉络膜结构及最佳矫正视力与术前HbA1c值的相关性。方法:临床病例对照研究。选择2016-10/2017-12在青岛市市立医院眼科中心符合入组条件的超声乳化白内障患者82例87眼,分为非糖尿病组和糖尿病组。依据术前HbA1c水平,将糖尿病组分为高HbA1c值组(HbA1c>7.0%)和正常HbA1c值组(HbA1c≤7.0%)。其中非糖尿病组(4%≤HbA1c≤6.0%)28例30眼,高HbA1c组28例29眼和正常HbA1c组26例28眼。运用频域光相干断层扫描(SD-OCT)检查各组患者术前1d,术后1d,1wk,1、3mo时黄斑中心凹视网膜厚度(CST)、黄斑总容积(CV)和黄斑中心凹脉络膜厚度(SFCT),采用多因素重复测量方差分析其变化,Pearson相关分析探究其与HbA1c值的相关性;同时比较各组患者术后黄斑水肿(PCME)发生率;进一步分析糖尿病患者HbA1c值与术后最佳矫正视力(CDVA)的关联性。结果:非糖尿病组、高HbA1c组和正常HbA1c组患者白内障术后1wk时CST分别为239.03±11.55、254.38±26.44、247.07±19.51μm,术后1mo时CST分别为241.00±11.15、271.55±61.05、248.64±38.28μm(F=3.001,P=0.048);其中高HbA1c值组和正常HbA1c值组比较有差异(P<0.05),且两组患者术后1wk,1mo时HbA1c值与CST之间在P=0.01水平上呈正相关关系(r术后1wk=0.338,r术后1mo=0.297)。三组患者术后发生PCME分别为0例、5眼(17%)和1眼(4%)。非糖尿病组、高HbA1c组和正常HbA1c组患者术后1wk时CDVA分别为0.07±0.06、0.12±0.10、0.09±0.08,术后1mo时CDVA分别为0.03±0.06、0.11±0.15、0.11±0.09,术后3mo时CDVA分别为0.02±0.04、0.08±0.12、0.06±0.06(F=3.272,P=0.045);其中高HbA1c值组和正常HbA1c值组比较无差异(P>0.05),两组患者HbA1c值与术后1wk,1、3mo(r术后1wk=0.425,r术后1mo=0.235,r术后3mo=0.332)CDVA(LogMAR)在P=0.01水平上两者显著相关且呈正相关关系。三组患者白内障术后CV、SFCT的组间变化趋势大致相同,其变化程度的组间无差异。结论:糖尿病患者术前HbA1c水平与超声乳化白内障术后黄斑区视网膜和脉络膜结构有一定的相关性;术前HbA1c>7.0%的患者术后发生黄斑水肿的风险增加。同时,糖尿病患者术前HbA1c水平与白内障术后最佳矫正视力密切相关;术前HbA1c值越高的患者术后视力提高越欠佳。     

“勾股定理”测量的左右心室电极间距离与心脏再同步化治疗临床疗效的相关性和预测性分析

【摘要】背景：再同步化治疗能改善心力衰竭患者的预后,但大约有1/3患者不能从中获益,也就是无反应者。目的：探讨在勾股定理方法测量下的实际左右心室电极间距离与心脏再同步化治疗临床疗效的相关性和预测性。方法：回顾性的研究在我院所有因符合CRT指征而行CRT植入术的患者,采集患者术前、术后6个月基本资料（年龄、左心室射血分数（LVEF）、左心室舒张末内径（LVEDD）、左心房前后径（LAAPD）、QRS 时限（QRSd）、N-端脑利钠肽前体(NT-proBNP)、美国纽约心脏病协会（NYHA）心功能分级等）;在术后的透视影像下,用游标卡尺测量正侧位左右心室间电极直接距离（L）（水平距离 V ,垂直距离 H）,正前位心脏横径（C）、胸腔横径（T）,根据勾股定理左、右心室电极植入位置间直接距离（DD2=V12+L22）或（DD2=V22+L12）;计算左、右心室电极植入位置间 DD/C。并根据术后心脏彩超变化或临床症状评估分为显著有效（A组）,有效（B组）和无效（C组）。结果：共有108个患者（平均年龄 64.34±9.35岁,51.9%男性,57.4%扩心病）纳入研究,A组（31）、有效组（56）和无效组（31）;三组患者术后6月的LVEF、6-MWT、LVEDD、QRSd、NT-ProBNP较术前均有明显改善（P＜0.05）,DD及DD/C在组内及组间均有统计学意义（P＜0.05）;且A组＞B组＞C组;多因素Logistic回归分析示DD和DD/C是CRT临床疗效的独立影响因素;在ROC曲线分析中,DD（DD/C）曲线下面积分别为0.709（0.713）和0.741（0.835）,A组和B组、B组和C组之间的DD（DD/C）截断值分别为54.84mm（0.551）和43.5mm（0.395）（P＜0.05）。结论：在勾股定理方法测量下的实际心室间电极距离与CRT临床疗效呈正相关,DD（DD/C）越大,CRT临床效果越好,并且也是预测CRT临床效果的预测因素。