偏最小二乘回归的离群点检测方法

目的本文研究了偏最小二乘回归中四种重要且常用的离群点检测图示方法:偏F检验、残差图与正态分位数图、主成份图(T/T图)与T2椭圆、样本点贡献图.方法通过实例分析了各种方法的优点和不足.结果离群点的检测与分离将有助于模型拟合精度和预测精度的提高.结论研究表明必须综合运用这些方法,并结合原始数据,才能取得比较好的检测效果.     

针刺对备用根猫背根节神经元IGF-Ⅰ表达的影响

目的观察胰岛素样生长因子-I（IGF—I）在正常猫、部分去背根猫及针刺部分去背根猫的L6手术侧背根节（DRG）表达的时空变化，以了解IGF—I与针刺促进脊髓可塑性的关系。方法25只成年健康雄猫随机分为5组：即正常组、备用根术后7d组与14d组（动物行单侧部分去背根手术，即切除一侧L1～L5、L7～S2背根节，保留L6为备用根）、针刺备用根术后7d组与14d组（动物行单侧部分去背根术后针刺L6脊神经外周支配区内的两组穴位）。动物于术后7d、14d分别处死，取各组（手术侧）L。背根节，-20℃恒冷箱切片，片厚20μm，用兔抗IGF—I（1：200）抗体行免疫组化ABC法染色。观察、计数并比较各组背根节IGF—I阳性神经元的分布、含量及时空变化。结果针刺备用根7d组，DRGIGF—I阳性神经元数较术后7d组明显增加（P〈0．05），但仍低于正常水平；针刺14d，DRG阳性神经元比术后14d亦增多（P〈0．01），且恢复至正常水平。与针刺7d组比较，DRGIGF—I阳性神经元在针刺14d时明显增多（P〈0．05）。结论针刺可增加针刺侧DRG内IGF—I阳性中小神经元数。提示针刺后IGF—I在背根节的表达变化可能与针刺促进脊髓可塑性有关。     

一种电阻抗断层成像的图像后处理算法

目的：研究电阻抗断层成像的图像处理方法,改善图像显示效果.方法：先利用相邻三角形单元的电导率估计节点的电导率,然后根据三角形单元3个顶点的电导率进行二维线性插值获得单元内任意点的电导率.结果：原始的按三角形单元分块显示的电阻抗断层成像的图像,可转换为光滑的图像.结论：图像显示效果得到很大的改善;此方法适用于所有三角形剖分的电阻抗断层成像的图像处理.     

TURBT术治疗T1T2期膀胱癌91例

目的:分析两种手术方法对T1T2期膀胱癌的治疗效果。方法:根据病史、体格检查、B超、3D-CT、膀胱镜活组织检查确诊的T1T2期膀胱癌152例,采用TURBT术(经尿道膀胱肿瘤切除术)91例,膀胱局部切除术61例,分析比较治疗效果。结果:两种手术方法疗效无显著特异性,患者生存率与肿瘤病理分期有直接相关性。结论:T1T2期膀胱癌采用TURBT术与采用膀胱局部切除术疗效相当,但TURBT费用低,创伤少,便于再次手术,有推广意义。     

Errors in Patient Positioning for Bone Mineral Density Assessment by Dual X-Ray Absorptiometry: Effect of Technologist Retraining

Improper positioning is one of the factors that can lead to incorrect bone mineral density (BMD) results. This study aimed to assess the frequencies of erroneous positioning during three periods: before retraining of the technologists (BR), after retraining (AR), and at the current timepoint 8 years after retraining (C). The BMD images of the first 150 consecutive patients who underwent DXA of the lumbar spine and hip during each of the three periods were retrospectively reviewed. Patients were excluded if they had severe scoliosis, rendering proper positioning impossible. Each BMD image was assessed by an International Society of Clinical Densitometry certified clinical densitometrist who was blinded to the date of the initial examination. For the lumbar spine in the BR group, the criteria frequently not met were inclusion of both iliac crests (33.8%), straightness (30.3%), and midline positioning (20.4%); the respective frequencies were significantly reduced to 0.8%?5.6%, 2.1%?3.0%, and 0%?2.8% in the AR and C groups (p < 0.05). For the hip in the BR group, the criteria frequently not met were straightness (52.8%) and internal rotation (21.8%); the respective frequencies were significantly reduced to 0%?4.2% and 8.3%?8.4% in the AR and C groups (p < 0.05). Overall improper positioning in the BR group was 49.3% and 57.3% at the lumbar spine and the hip, respectively; the respective frequencies were reduced to 9.3% and 12.7% in the AR group, and to 2.7% and 7.3% in the C group. The least significant change values for the lumbar spine, femoral neck, and total hip also became smaller after retraining. Retraining the technologists improved patient positioning, as evidenced by the decreased frequencies of erroneous positioning and the improved least significant change values after the retraining.     

Current aspects of therapeutic reduction mammaplasty for immediate early breast cancer management: An update

Breast-conservation surgery (BCS) is established as a safe surgical treatment for most patients with early breast cancer. Recently, advances in oncoplastic techniques are capable of preserving the breast form and quality of life. Although most BCS defects can be managed with primary closure, the aesthetic outcome may be unpredictable. Among technical options, therapeutic reduction mammaplasty (TRM) remains a useful procedure since the BCS defect can be repaired and the preoperative appearance can be improved, resulting in more proportional breasts. As a consequence of rich breast tissue vascularization, the greater part of reduction techniques have based their planning on preserving the pedicle of the nipple-areola complex after tumor removal. Reliable circulation and improvement of a conical shape to the breast are commonly described in TRM reconstructions. With an immediate approach, the surgical process is smooth since both procedures can be carried out in one operative setting. Additionally, it permits wider excision of the tumor, with a superior mean volume of the specimen and potentially reduces the incidence of margin involvement. Regardless of the fact that there is no consensus concerning the best TRM technique, the criteria is determined by the surgeon’s experience, the extent/location of glandular tissue resection and the size of the defect in relation to the size of the remaining breast. The main advantages of the technique utilized should include reproducibility, low interference with the oncological treatment and long-term results. The success of the procedure depends on patient selection, coordinated planning and careful intra-operative management.     

The R.E.N.A.L. Nephrometric Nomogram Cannot Accurately Predict Malignancy or Aggressiveness of Small Renal Masses Amenable to Partial Nephrectomy

Introduction/BackgroundThe prediction of histology of SRM could be essential for their management. The RNN is a statistical tool designed to predict malignancy or high grading of enhancing renal masses. In this study we aimed to perform an external validation of the RNN in a cohort of patients who received a PN for SRM.Materials and MethodsThis was a multicentric study in which the data of 506 consecutive patients who received a PN for cT1a SRM between January 2010 and January 2013 were analyzed. For each patient, the probabilities of malignancy and aggressiveness were estimated preoperatively using the RNN. The performance of the RNN was evaluated according to receiver operating characteristic (ROC) curve, calibration plot, and decision curve analyses.ResultsThe area under the ROC curve for malignancy was 0.57 (95% confidence interval [CI], 0.51-0.63; P = .031). The calibration plot showed that the predicted probability of malignancy had a bad concordance with observed frequency (Brier score = 0.17; 95% CI, 0.15-0.19). Decision curve analysis confirmed a poor clinical benefit from use of the system. The estimated area under the ROC curve for high-grade prediction was 0.57 (95% CI, 0.49-0.66; P = .064). The calibration plot evidenced a bad concordance (Brier score = 0.15; 95% CI, 0.13-0.17). Decision curve analysis showed the lack of a remarkable clinical usefulness of the RNN when predicting aggressiveness.ConclusionsThe RNN cannot accurately predict histology in the setting of cT1a SRM amenable to PN.     

一元线性回归算法在生物化学分析仪上的应用研究

目的：实现一种应用于生物化学分析仪的定量分析方法。方法：利用一元一次线性回归模型，结合标准曲线来计算待测样本的浓度值。结果：经过验证和临床测试，该算法可满足性能要求，且有效可行。结论：该方法能很好地满足临床应用，并能扩展到工业检测、食品安全等领域。     

Dynamic mechanisms underlying afterdischarge: A human subdural recording study

ObjectiveNo synoptic understanding exists of how and why afterdischarges (ADs) occur following electrical stimulation of the cerebral cortex. Based on human observations, we formulated a general mechanism for the emergence of ADs.MethodsWe retrospectively analysed spectra of AD time-series and control segments of the resting electrocorticogram (ECoG) in 15 epilepsy patients who underwent cortical stimulation mapping. The observations led to the development of phenomenological models for AD emergence and morphology.ResultsAn analytical relationship exists between the spectrum of the baseline ECoG and the ensuing AD, characterised by ‘condensation’ of the main baseline spectral cluster, with variable inclusion of higher harmonics of the condensate.ConclusionsADs arise by synchronisation of pre-existing local field potentials, likely through temporary inactivation of inhibitory interneurons from repetitive stimulation-induced depolarization. The appearance of higher harmonics indicates that ADs are further modulated by recurrent feedback, likely from the entrained activity of single units.SignificanceFor the first time, a putative mechanism is suggested for AD emergence following electrical stimulation of the cerebral cortex. Insight is also offered into several empirical observations regarding ADs, detailed in the main text. More generally, a novel conceptual synthesis emerges between the behaviour of electrically-excited cortex and the physics of nonlinearly coupled multi-oscillator systems.     

Laparoscopic partial cystectomy with mucosal stripping of extraluminal duodenal duplication cysts

Duodenal duplication cysts are rare congenital anomalies.Duodenal duplication should be considered in the differential diagnosis of patients who present with abdominal symptoms with cystic structures neighboring the duodenum.Here,we present an 8-year-old girl with a duodenal duplication cyst treated with partial cystectomy with mucosal stripping performed laparoscopically.Laparoscopic surgery can be considered as a treatment option for duodenal duplication cysts,especially in extraluminal locations.