Pilzerkrankungen des Auges

Wiener Medizinische Wochenschrift - Die Pilzinfektionen des Auges sind ernstzunehmende Augenerkrankungen. Die Diagnose kann oft durch die Ätiologie und die Symptome gestellt werden. Die...     

A novel model for biomechanical behavior of human brain in epidural hematoma injuries

To obtain an appropriate model for the simulation of the biomechanical behavior of brain tissue and the deformation of ventricles, in particular, we have developed a novel computerized plain strain finite element model. For optimum results, a multiple loading solutions approach using various tissue parameters for the simulation of epidural hematoma have been tested. For this purpose, CT-Scan of a patient with traumatic epidural hematoma has been modeled. By changing the tissue parameters (E and nu) and increasing intraventricular pressure gradient, the displacement of similar points in the modeled ventricle was compared with the true values obtained from patient's CT-Scan taken 3 months later after the resolution of hematoma. The magnitudes leading to least errors were determined. Best solutions were obtained with E=11-12 kPa and DeltaP=1.25-1.5 kPa (7.5-9.4 mmHg), which were consistent with the patient's clinical condition. Biomechanical modeling of unilateral displacement loadings, which are the conditions similar to surgical navigation systems, without considering ventricular geometry and their internal pressure resulted in unacceptable results.     

Incorporating an Exercise Detection,Grading, and Hormone Dosing Algorithm Into the Artificial Pancreas Using Accelerometry and Heart Rate

In this article, we present several important contributions necessary for enabling an artificial endocrine pancreas (AP) system to better respond to exercise events. First, we show how exercise can be automatically detected using body-worn accelerometer and heart rate sensors. During a 22 hour overnight inpatient study, 13 subjects with type 1 diabetes wearing a Zephyr accelerometer and heart rate monitor underwent 45 minutes of mild aerobic treadmill exercise while controlling their glucose levels using sensor-augmented pump therapy. We used the accelerometer and heart rate as inputs into a validated regression model. Using this model, we were able to detect the exercise event with a sensitivity of 97.2% and a specificity of 99.5%. Second, from this same study, we show how patients’ glucose declined during the exercise event and we present results from in silico modeling that demonstrate how including an exercise model in the glucoregulatory model improves the estimation of the drop in glucose during exercise. Last, we present an exercise dosing adjustment algorithm and describe parameter tuning and performance using an in silico glucoregulatory model during an exercise event.     

Obesity and Obesity Shape Markedly Influence Spine Biomechanics: A Subject-Specific Risk Assessment Model

Underlying mechanisms of obesity-related back pain remain unexplored. Thus, we aim to determine the effect of obesity and its shapes on the spinal loads and the associated risks of injury. Obesity shapes were initially constructed by principal component analysis based on datasets on 5852 obese individuals. Spinal loads, cycles to vertebral failure and trunk stability margin were estimated in a subject-specific trunk model taking account of personalized musculature, passive ligamentous spine, obesity shapes, segmental weights, spine kinematics and bone mineral density. Three obesity shapes (mean and extreme abdominal circumferences) at three body weights (BWs) of 86, 98 and 109 kg were analyzed. Additional BW (12 kg) increased spinal loads by ~11.8%. Higher waist circumferences at identical BW increased spinal forces to the tune of ~20 kg additional BW and the risk of vertebral fatigue compression fracture by 3–7 times when compared with smaller waist circumferences. Forward flexion, greater BW and load in hands increased the trunk stability margin. Spinal loads markedly increased with BW, especially at greater waist circumferences. The risk of vertebral fatigue fracture also substantially increased at greater waist circumferences though not at smaller ones. Obesity and its shape should be considered in spine biomechanics.     

Timing of Surgery and the Role of Adjuvant Radiotherapy in Ewing Sarcoma of the Chest Wall: A Single-institution Experience

Background

Ewing sarcoma (ES) is the most common chest wall malignancy in adolescents. Current therapy incorporates chemotherapy to treat systemic disease and radiotherapy to assist with local control. We sought to evaluate the timing of surgery and role of adjuvant radiotherapy.

Methods

We reviewed the St. Jude Children??s Research Hospital chest wall ES experience from 1979 to 2009. Patient demographics, tumor characteristics, treatment variables, and outcomes were analyzed with respect to timing of surgery and use of adjuvant radiotherapy.

Results

Our cohort consisted of 36 patients with chest wall ES; median follow-up was 14.2?years, and 15-year estimate of overall survival was 66?%. In patients with localized disease, the timing of surgery (up-front vs. delayed) did not impact margin negativity or the use of adjuvant radiotherapy, but it did decrease the extent of chest wall resection. When considering radiotherapy in patients with localized disease, we found that patients who did not receive radiotherapy had smaller tumor size (median 6 vs. 10?cm) (p?=?0.04) and were more likely to have had negative margins (p?=?0.01) than patients who received adjuvant radiotherapy. One patient in each group developed a locoregional recurrence. The 15-year estimated of overall survival for patients who received adjuvant radiotherapy was 80 versus 100?% for those who did not.

Conclusions

Delayed surgery decreased the extent of chest wall resection and helped define a patient population with favorable tumor biology. Patients with complete pathologic responses to chemotherapy, and those with tumors <8?cm and negative surgical margins may be spared adjuvant radiotherapy without any decrement in overall survival.     

Structural Polymer-Based Carbon Nanotube Composite Fibers: Understanding the Processing–Structure–Performance Relationship

Among the many potential applications of carbon nanotubes (CNT), its usage to strengthen polymers has been paid considerable attention due to the exceptional stiffness, excellent strength, and the low density of CNT. This has provided numerous opportunities for the invention of new material systems for applications requiring high strength and high modulus. Precise control over processing factors, including preserving intact CNT structure, uniform dispersion of CNT within the polymer matrix, effective filler–matrix interfacial interactions, and alignment/orientation of polymer chains/CNT, contribute to the composite fibers’ superior properties. For this reason, fabrication methods play an important role in determining the composite fibers’ microstructure and ultimate mechanical behavior. The current state-of-the-art polymer/CNT high-performance composite fibers, especially in regards to processing–structure–performance, are reviewed in this contribution. Future needs for material by design approaches for processing these nano-composite systems are also discussed.     

Clinical aspects of infertile 47,XYY patients: a retrospective study

47,XYY syndrome is a sex chromosomal anomaly in men, which may be associated with infertility and has an incidence of 0.1% of male births. The clinical and paraclinical characteristics of men suffering from this anomaly have not been fully described. In this retrospective study, we present 37 cases of 47,XYY infertile men with sperm counts varying from normal to azoospermia, referred to the Genetics Laboratory at the Royan Institute, Iran. Thirteen individuals were mosaic and 24 non-mosaics. Non-mosaic patients were classified as azoospermic (nine cases) and normospermic/oligozoospermic men (15 cases). Two of the non-mosaic and three mosaic patients had secondary infertility. In addition, 13 of them underwent IUI, IVF or ICSI, and in seven cases, there was a biochemical pregnancy. The remaining 14 patients did not have ART. The 47,XYY syndrome is relatively unusual and can be missed clinically because of the lack of symptoms and of diverse phenotypes. Diagnosis of this aneuploidy can provide valuable data for counselling and early management of the patients who undergo fertility evaluation.