Biomechanical Evaluation of the Accuracy in Radiographic Assessment of Femoral Component Migration Measurement after Total Hip Arthroplasty

Introduction: Implant subsidence is one criteria utilized to monitor for prosthesis loosening after total hip arthroplasty (THA) with initial implant subsidence assessment often done utilizing plain radiographs. The specific aim of this study was to identify the most reliable references when using plain radiographs to establish an image magnification with the goals being easy to use, inexpensive, reliable, and accurate. Methods: Two femoral stem implants (stem lengths: 127mm, 207mm) were utilized to simulate hemiarthroplasty of the hip with composite femurs. Different combinations of femoral stem distances from the radiographic film (ODD), source-detector differences (SDD), hip rotation, and hip flexion were elected. Standardized anterior-posterior pelvis for each parameter combination setup were taken. Radiographic measurements (head diameter, stem length, stem seating length) were undertaken five times by three examiners. Radiographic image magnification factors were generated from two references (head diameter and stem length). Radiograph measurement reproducibility and stem seating length errors using these magnification factors were evaluated. Results: High level of repeated measurements reliability was found for head diameter (99 ± 0%) and stem length (90 ± 7%) measurements, whereas seating length measurements were less reliable (76 ± 6%). Stem length error using the femoral head magnification factor yielded 11% accuracy. Stem seating length error using both magnification factors were not reliable (< 7% accuracy). All parameters, except SDD, showed significant effect on calibrated measurement error. Conclusions: Current methods of assessing implant subsidence after THA using plain radiographs are inaccurate or reliable. Clinicians should recognize these limitations and be cautious when diagnosing implant stability using plain radiographs alone

The Non-Unconscionability of Condominium Recreation Leases

The authors evaluate the theory of unconscionability as a basis for challenging long-term condominium recreation leases in Florida. They discuss the situation underlying such challenges and examine recent attempts to apply common law and U.C.C. unconscionability principles to recreation leases. An analysis of the realities of condominium development serves to dispel several commonly held misconceptions about recreation leases. The authors also analyze the presumption of unconscionability under the Florida Condominium Act, contrasting it with the proposed Federal Condominium Act. Recognizing the inefficacy of the unconscionability approach, the authors briefly discuss the recreation lease buy-out as a more feasible alternative solution

The Non-Unconscionability of Condominium Recreation Leases

The authors evaluate the theory of unconscionability as a basis for challenging long-term condominium recreation leases in Florida. They discuss the situation underlying such challenges and examine recent attempts to apply common law and U.C.C. unconscionability principles to recreation leases. An analysis of the realities of condominium development serves to dispel several commonly held misconceptions about recreation leases. The authors also analyze the presumption of unconscionability under the Florida Condominium Act, contrasting it with the proposed Federal Condominium Act. Recognizing the inefficacy of the unconscionability approach, the authors briefly discuss the recreation lease buy-out as a more feasible alternative solution

Electromyographic Analysis of Abdominal and Low Back Musculature during Use of an Experimental Stationary Bicycle

Background and Purpose. Currently, stationary bicycles do not incorporate exercise for the abdominal and low back musculature. An experimental stationary bicycle, the Magnus Cycle, has been developed to increase trunk muscle activation and, at the same time, provide aerobic conditioning. The purpose of this study is to assess the activity of the rectus abdominus, external oblique, erector spinae, rectus femoris and biceps femoris muscles during a stationary cycling setting and during a tilt-in-space setting of the Magnus Cycle. Subjects. Sixteen subjects, both men and women, between the ages of 18 and 30 participated in this study. Methods. Surface electromyography (EMG) was used to assess muscle activity from the rectus abdominus, external oblique, erector spinae, rectus femoris, and biceps femoris muscles during each phase of stationary and oscillating exercise. The raw EMG signal was rectified, smoothed and normalized to the respective muscle maximal voluntary contraction prior to data analysis. A repeated measures t-test was utilized to assess differences in EMG activity between minutes one and three of stationary cycling. DIfferences in the oscillating condition for forward and backward tilt was assessed using a repeated measures ANOVA, alpha = 0.05. For trials without differences between oscillations, one way ANOV A was performed to determine differences between stationary, foot forward, and foot backward tilt conditions. Results. In the feet forward position, the rectus abdominis, external obliques, and rectus femoris demonstrated significantly higher EMG activation compared to both the stationary and feet backward conditions (p\u3c.05). Activity of the erector spinae and biceps femoris muscles were not affected by the feet forward position. However, in the feet backward position, the erector spinae and biceps femoris muscles demonstrated significantly higher EMG activity compared to the stationary position and feet forward positions (p\u3c.05). The rectus abdominis, external obliques, and rectus femoris muscles were not affected by the feet backward condition. Discussion and Conclusion. The tilting Magnus Cycle significantly enhances activation of the rectus abdominis, external oblique, erector spinae, rectus femoris, and biceps femoris muscles compared to stationary cycling. The enhanced trunk muscle activity may make the Magnus Cycle a better option for a quicker, more beneficial workout than standard stationary bicycles

Отношение фазовых объемов реакций одиночного и двойного фоторождения пионов на дейтроне

В работе выполнен расчет фазовых объемов реакций одиночного и двойного фоторождения пионов на дейтроне. Проведено количественное сравнение фазовых объемов в зависимости от энегрии гамма-кванта. Для определения экспериментального фазового объема использовались ограничения в эксперименте DEUTERON на ВЭПП-3 ИЯФ СО РАН.In this paper, we analyzed the ratio of the experimental and total phase volumes of reactions of single and double pion photoproduction on deuterons as a function of the photon energy. To determine the experimental phase volume, limitations were used in the DEUTERON experiment at the VEPP-3 at INP SB RAS

Изготовление и исследование образцов из неметаллического материала для визуального контроля

В ходе практических экзаменов в рамках аттестации персонала в области неразрушающего контроля используются аттестационные образцы, содержащие один или несколько дефектов. В настоящее время существуют разные образцы для аттестации персонала, например стальные трубы, металлические пластины с дефектными сварными швами, но они выполнены из металлов, а т. к. аттестовать специалистов необходимо на образцах из материала, соответствующего действительному объекту контроля из перечня опасных производственных объектов, то предлагается вариант изготовления экзаменационного образца из неметаллического материала. Был разработан аттестационный образец из неметаллического материала для аттестации персонала в области неразрушающего контроля по визуальному и измерительному контролю.During the practical examinations in the framework of personnel certification in the field of nondestructive testing, attestation samples containing one or more defects are used. Currently, there are different samples for personnel certification, for example steel pipes, metal plates with defective welds, but they are made of metals, and since it is necessary to certify specialists on samples from the material corresponding to the actual object of control from the list of hazardous production objects, a variant of manufacturing an examination sample made of nonmetallic material. A certification sample was prepared from non-metallic material for the certification of personnel in the field of nondestructive testing by visual and measuring control