Quantitative phase-amplitude microscopy. III. The effects of noise.

We explore the effect of noise on images obtained using quantitative phase-amplitude microscopy - a new microscopy technique based on the determination of phase from the intensity evolution of propagating radiation. We compare the predictions with experimental results and also propose an approach that allows good-quality quantitative phase retrieval to be obtained even for very noisy data.

Glenohumeral translations are increased after a type II superior labrum anterior-posterior lesion: a cadaveric study of severity of passive stabilizer injury.

The effects of simulated type II superior labrum anterior-posterior (SLAP) lesions were studied to determine whether the severity of the lesion affected glenohumeral joint translations. A robotic/universal force-moment sensor testing system was used to simulate load-and-shift tests by applying an anterior or posterior load of 50 N to each shoulder. The apprehension test for anterior instability was simulated by applying an anterior load of 50 N with an external rotation torque of 3 Nm at 30 degrees and 60 degrees of abduction.

Quantitative phase radiography with polychromatic neutrons.

We develop and experimentally demonstrate a formalism that allows accurate phase imaging using neutron sources producing highly polychromatic beams. The results of measurements from a rectangular block of silicon compare favorably with theoretical simulations based upon the known composition and geometry of the block. The increased flux and reduced exposure times will permit a simple extension of the technique to tomographic phase imaging.

A quantitative analysis of valgus torque on the ACL: a human cadaveric study.

The loads needed to elicit a positive pivot shift test in a knee with an anterior cruciate ligament (ACL) rupture have not been quantified. The coupled anterior tibial translation (ATT), coupled internal tibial rotation (ITR), and the in situ force in the ACL in response to a valgus torque, an inherent component of the pivot shift test, were measured in 10 human cadaveric knee specimens. Using a robotic/universal force-moment sensor testing system, valgus torques ranging from 0.

Mal-aligning humeral offset may not effect shoulder hemiarthroplasty: a biomechanical study.

Background: Component mal-positioning may contribute to a poor clinical outcome after hemiarthroplasty. Eccentric head components, recently introduced, allow posterior offset of the humeral head relative to the shaft so the purpose of this study was to determine effects of mal-aligning humeral head offset.

Material/methods: Five glenohumeral joints were each placed in 60 and 90 degrees of shoulder abduction and in apprehension positions using a custom shoulder-testing device.

[Biomechanical tests for type II SLAP lesions of the shoulder joint before and after arthroscopic repair].

Superior labral anterior-to-posterior (SLAP) lesions can cause shoulder pain partly by causing glenohumeral instability. The purpose of this study was to examine the effect of a simulated type II SLAP lesion and subsequent repair on glenohumeral translation of the vented shoulder. In eight cadaver joints, a robotic/UFS testing system was used to measure joint translation by applying an anterior, posterior, or inferior load of 50 N to each shoulder.

The collagen fibers of the anteroinferior capsulolabrum have multiaxial orientation to resist shoulder dislocation.

Instability of the glenohumeral joint can be associated with anteroinferior capsulolabral rupture. To understand its static stabilizing effect better, the collagen fiber orientation of the inferior glenohumeral ligament (IGHL), a component of the anteroinferior capsulolabrum, was studied with a small angle light scattering technique. Three rectangular samples (approximately 11 x 6 mm) were excised from the axillary pouch, one from the anterior band (AB) of the IGHL and one control sample from the long head of the biceps tendon of 7 cadaveric shoulders.

Glenohumeral joint translation after arthroscopic thermal capsuloplasty of the posterior capsule.

Treatment of recurrent posterior or multidirectional glenohumeral instability in athletes with traditional operative management has produced variable results at long-term follow-up. The purpose of this study was to determine whether an arthroscopic thermal capsuloplasty of the posterior capsule with a radiofrequency probe significantly decreases anterior-posterior glenohumeral translation. Successive posterior and anterior loads of 10, 15, and 20 N were applied sequentially to 7 cadaveric shoulder joints that were mounted in a translation testing apparatus with an electromagnetic tracking device measuring posterior and anterior glenohumeral translation.

Cost-effectiveness of PET in the diagnosis of Alzheimer disease.

Purpose: To evaluate the cost-effectiveness of positron emission tomography (PET) in the diagnosis of Alzheimer disease (AD) in community-dwelling patients with mild or moderate dementia who present to specialized AD centers.

Materials And Methods: A decision-analytic model was used to compare costs and quality-adjusted life years (QALYs) associated with strategies involving single photon emission computed tomography (SPECT), dynamic susceptibility-weighted contrast material-enhanced magnetic resonance (MR) imaging, and PET as functional imaging adjuncts to the standard clinical work-up. Sensitivity analyses were performed to examine changes in test characteristics, health-related quality-of-life survey instruments, therapeutic effectiveness, and treatment rules.

Glenohumeral joint translation after arthroscopic thermal capsuloplasty of the rotator interval.

The treatment of recurrent anterior, posterior, or multidirectional glenohumeral instability by operative closure of the rotator interval has been proposed. The purpose of this study was to determine whether arthroscopic thermal capsuloplasty of the rotator interval with the radiofrequency probe significantly decreases anterior-posterior glenohumeral translation. Anterior and posterior loads of 10, 15, and 20 N were sequentially applied to 8 cadaveric shoulder joints while mounted in a translation testing apparatus with an electromagnetic tracking device measuring anterior and posterior glenohumeral translation.

Cost-effectiveness of hepatic metastasectomy in patients with metastatic colorectal carcinoma: a state-transition Monte Carlo decision analysis.

Objective: To evaluate the cost-effectiveness of hepatic resection ("metastasectomy") in patients with metachronous liver metastases from colorectal carcinoma (CRC), and to investigate the impact of operative and follow-up strategies on outcomes, cost, and cost-effectiveness.

Summary Background Data: There is substantial evidence that resection of CRC liver metastases can result in long-term survival in some patients. However, several unresolved issues are difficult to address using currently available clinical data.

Measurement of the spatial coherence function of undulator radiation using a phase mask.

A measurement of the horizontal coherence function of 7.9 keV radiation from an undulator beam line at the Advanced Photon Source is reported. X-ray diffraction from a phase-shifting mask was used, and the coherence function was measured as a function of the width of beam-conditioning slits in the beam line.

Shoulder muscle reflex latencies under various levels of muscle contraction.

Previous research in relaxed muscles shows that muscle reflex latencies are too slow to protect the shoulder. However, during athletic activity when injury occurs, some level of shoulder muscle contraction typically exists. The purpose of the current study was to assess shoulder muscle reflex latencies under various levels of muscle contraction.

Glenohumeral translations are only partially restored after repair of a simulated type II superior labral lesion.

Background: The effect on joint stability of repair of type II superior labrum and biceps anchor lesions is unknown.

Hypothesis: Increased translations of the glenohumeral joint after a simulated type II lesion will be reduced after the lesion is repaired.

Study Design: Controlled laboratory study.

Differential indicators of diabetes-induced oxidative stress in New Zealand White rabbits: role of dietary vitamin E supplementation.

Determination of reliable bioindicators of diabetes-induced oxidative stress and the role of dietary vitamin E supplementation were investigated. Blood (plasma) chemistries, lipid peroxidation (LPO), and antioxidant enzyme activities were measured over 12 weeks in New Zealand White rabbits (control, diabetic, and diabetic + vitamin E). Cholesterol and triglyceride levels did not correlate with diabetic state.

Shoulder biomechanics and muscle plasticity: implications in spinal cord injury.

After spinal cord injury, excessive burden falls on the upper extremity, especially the shoulder. Overall, 51% of persons with spinal cord injury have shoulder problems. Common shoulder problems in persons with spinal cord injury begin with muscle imbalance that can lead to glenohumeral instability, impingement disease, rotator cuff tears, and subsequent degenerative joint disease.

Muscles may contribute to shoulder dislocation and stability.

Joint instability is one of the most common human afflictions, affecting not only the hip, knee, and shoulder but all joints of the body. Surgical repair for joint instability is done commonly, yet has not been able to restore function consistently. Pain, recurrence of instability, joint stiffness, muscle injury, and degenerative joint disease are all too common sequelae.

The efficacy of using a personal stereo to treat auditory hallucinations. Preliminary findings.

This article presents preliminary findings from the first participant to complete an experiment assessing the efficacy of the personal stereo in treating auditory hallucinations. O.C.

Gender differences in patellofemoral joint biomechanics.

Patellofemoral pain is associated with patellar malalignment and quadriceps weakness which are seen more commonly in women. The objective of the current study was to determine the effects of gender, vastus medialis strength, and tibial rotation on patellofemoral joint biomechanics. Twelve fresh-frozen knees from cadavers were tested using a custom knee jig.

Effects of simulated vastus medialis strength variation on patellofemoral joint biomechanics in human cadaver knees.

Selective strengthening of the vastus medialis (VM) muscle is a conservative treatment used to address some patellofemoral joint (PFJ) problems. The objective of this study was to examine the effects of varying VM strength on PFJ kinematics and contact pressures and areas. We tested five fresh-frozen cadaveric knees using a custom knee jig, which permits the simulation of physiologic quadriceps loading while also allowing the VM force to be varied.

Colorectal cancer screening issues: a role for CT colonography?

Colorectal cancer is the third most common cancer in the United States and will cause 56,700 deaths in 2001, despite the availability of screening tests capable of detecting the disease at earlier stages and reducing mortality. This article reviews the natural history of colorectal cancer, common risk factors and prevention strategies, and the strengths, limitations, and cost effectiveness of available screening tests. Although reminders to undergo colorectal cancer screening have become commonplace in the popular media, compliance with screening guidelines remains poor.

Quantitative assessment of glenohumeral translation.

Cutaneous electromagnetic position sensors were used to quantify anteroposterior laxity of the shoulder. Forty-three female athletes were tested (27 were soccer players and 16 were swimmers). The athletes had a mean age of 18.

Cadaveric study of glenohumeral translation using electromagnetic sensors.

Clinical methods for measuring shoulder translation rely heavily on the experience of the examiner and remain largely subjective, prone to errors of interobserver and intraobserver reproducibility. Accurate in vitro methods of measuring glenohumeral translation exist. The purpose of the current study was to evaluate the accuracy of computerized electromagnetic spatial sensors applied to the skin, in measuring glenohumeral translation under simulated conditions of a standard shoulder examination.

Open surgical repair restores joint forces that resist glenohumeral dislocation.

Traumatic anterior shoulder instability is a clinical problem often observed in athletes participating in overhead activities. The standard treatment for this condition is surgical repair, which may be accomplished by an open or arthroscopic procedure. The current authors assessed the strength of open repair, by comparing glenohumeral joint forces in intact specimens with specimens with anterior dislocation and open repair.

Variation in the glenoid origin of the anteroinferior glenohumeral capsulolabrum.

Restoration of the anteroinferior capsulolabrum, including the labrum and origin of the anterior band of the inferior glenohumeral ligament is crucial during Bankart repair. The purpose of the current study was to describe variations in this anatomy near the glenoid. The histologic and gross anatomy were studied in 10 fresh-frozen glenohumeral joints from adult cadavers.