Embedding Fiber Bragg Grating Sensors in Carbon Composite Structures for Accurate Strain Measurement

Fiber Bragg grating (FBG) sensors written by femtosecond laser pulses in polyamide-coated low bending loss optical fibers are successfully embedded in carbon composite structures, following laminating and light resin molding processes which optimize the size of each ply to address esthetic, drapability, and structural requirements of the final components. The sensors are interrogated by a tunable laser operating at around 1.55 μm, and their response to temperature and strain variations is characterized in a thermally controlled chamber and by bending tests using suspended calibrated loads and a laser scanning system. Experimental results are in good agreement with simulations, confirming that the embedding process effectively overcomes potential issues related to FBG spectral distortion, birefringence, and losses. In particular, the effects of the composite material nonhomogeneity and FBG birefringence are investigated to evaluate their impact on the monitoring capabilities. A bimaterial mechanical beam model is proposed to characterize the orthotropic laminates, pointing out better accuracy in estimating the applied load with respect to the classical homogeneous beam model. A comparative analysis, performed on different instrumented carbon composite samples and supported by theory, points out the repeatability of the FBG sensors' embedding process and the effectiveness of the technology for real-time accurate strain measurement. Based on such measurements, damages and/or changes in local stiffness can be effectively detected, allowing for structural health monitoring (SHM) of composite structures for applications in specific industrial fields such as automotive and aerospace

Bilateral Simultaneous Femoral Neck Fracture Mimicking Abdominal Pain in a Cerebral Palsy Patient

Simultaneous bilateral femoral neck fractures are unusual lesions, generally associated with an underlying condition which causes impaired bone mineralization, triggered by an increased bone stress. We present a 24-year-old cerebral palsy patient, who was previously evaluated in another institution due to inability to walk, interpreted as abdominal pain. No alteration in blood analysis or abdominal X-rays was found. As no response to treatment was observed, a new abdominal X-ray was taken, which incidentally depicted bilateral medial femoral neck fracture. He was referred to our practice after a resection arthroplasty was offered in another institution. After admission, bilateral one-stage THA was performed. Several reports emphasize bone disease as a major precipitating factor, and there is an increased incidence of hip fractures in chronic epilepsy, renal osteodystrophy, and chronic steroid use. Femoral head resection has been proven to be effective in immobilized patients, whereas this was not a reasonable option in this patient who presented walking ability. Despite the treatment election, primary care physicians should be aware of and alert to the possibility of fractures in patients with neurological disorders and calcium metabolism alterations. Late diagnosis of orthopedic injuries in this type of patients may lead to permanent disability

Association between psoas abscess and prosthetic hip infection: a case-control study

Background and purpose The relationship between prosthetic hip infection and a psoas abscess is poorly documented. We determined the frequency of prosthetic hip infections associated with psoas abscesses and identified their determinants

Impregnation of bone chips with antibiotics and storage of antibiotics at different temperatures: an in vitro study

<p>Abstract</p> <p>Background</p> <p>Allograft bone used in joint replacement surgery can additionally serve as a carrier for antibiotics and serve as a prophylaxis against infections. However, <it>in vitro </it>dose-response curves for bone chips impregnated with different kinds of antibiotics are not available. In addition, while it would be desirable to add the antibiotics to allograft bone chips before these are stored in a bone bank, the effects of different storage temperatures on antibiotics are unknown.</p> <p>Methods</p> <p>Five different antibiotics (cefazolin, clindamycin, linezolid, oxacillin, vancomycin) were stored, both as pills and as solutions, at -80°C, -20°C, 4°C, 20°C and 37°C; in addition, bone chips impregnated with cefazolin and vancomycin were stored at -80°C and -20°C. After 1 month, 6 months and 1 year, the activity of the antibiotics against <it>Staphylococcus epidermidis </it>was measured using an inoculated agar. The diameter of the <it>S. epidermidis</it>-free zone was taken as a measure of antibiotic activity.</p> <p>In a separate experiment, <it>in vitro </it>dose-response curves were established for bone chips impregnated with cefazolin and vancomycin solutions at five different concentrations.</p> <p>Finally, the maximum absorbed amounts of cefazolin and vancomycin were established by impregnating 1 g of bone chips with 5 ml of antibiotic solution.</p> <p>Results</p> <p>A decrease of the <it>S. epidermidis</it>-free zone was seen with oxacillin and cefazolin solutions stored at 37°C for 1 month, with vancomycin stored at 37°C for 6 months and with cefazolin and oxacillin solutions stored at 20°C for 6 months. The activity of the other antibiotic solutions, pills and impregnated bone chips was not affected by storage. The <it>in vitro </it>dose-response curves show that the free-zone diameter increases logarithmically with antibiotic concentration. The absorbed antibiotic amount of one gram bone chips was determined.</p> <p>Conclusions</p> <p>Storage of antibiotics in frozen form or storage of antibiotic pills at temperatures up to 37°C for 12 months does not affect their activity. However, storage of antibiotic solutions at temperatures above 20°C does affect the activity of some of the antibiotics investigated. The <it>in vitro </it>dose-response curve can be used to determine the optimal concentration(s) for local application. It provides the opportunity to determine the antibiotic content of bone chips, and thus the amount of antibiotics available locally after application.</p

Spanish Teachers\u27 Sense of Humor and Student Performance on the National Spanish Exams

Research suggests that second/foreign language teachers\u27 sense of humor is directly related to many outcomes for teachers and their students. This research investigates the relationship between the perceived sense of humor of in-service Spanish teachers\u27 (n = 102) and their students\u27 (n = 5,419) score on the National Spanish Exams using the affective filter hypothesis as a conceptual framework. Statistical analyses indicate that Spanish teacher sense of humor is related to student achievement on the exams. This research has implications for language teachers and teacher educators

A Reverse Transcriptase-PCR Assay for Detecting Filarial Infective Larvae in Mosquitoes

The Global Programme for the Elimination of Lymphatic Filariasis (GPELF) was launched in the year 1998 with the goal of eliminating lymphatic filariasis by 2020. As the success of mass drug administration (MDA) in the global program drives the rates of infection in endemic populations to very low levels, the development of new, highly sensitive methods are required for monitoring transmission by screening mosquitoes for the presence of L3 infective larvae. The current method of mosquito dissection to identify L3 larvae is laborious and insensitive and is not amenable to screening large numbers of mosquitoes. Existing molecular assays for the detection of filarial parasite DNA in mosquitoes are sensitive and can easily screen large numbers of vectors. However, current PCR-based methods cannot distinguish between infected mosquitoes that contain any stage of the parasite and infective mosquitoes that harbor third stage larvae (L3) capable of establishing new infections in humans. This paper reports the first development of a molecular L3-detection assay for a filarial parasite in mosquitoes based on RT-PCR detection of an L3-activated gene transcript. This strategy of detecting stage-specific messenger RNA from filarial parasites may also prove useful for detecting infective stages of other vector-borne pathogens