Numerical spatial impulse response calculations for a circular piston radiating in a lossy medium.

Exact analytical expressions for the spatial impulse response are available for certain transducer geometries. These exact expressions for the spatial impulse response, which are only available for lossless media, analytically evaluate the Rayleigh integral to describe the effect of diffraction in the time domain. To extend the concept of the spatial impulse response by including the effect of power law attenuation in a lossy medium, time-domain Green's functions for the Power Law Wave Equation, which are expressed in terms of stable probability density functions, are computed numerically and superposed. Numerical validations demonstrate that the lossy spatial impulse for a circular piston converges to the analytical lossless spatial impulse response as the value of the attenuation constant grows small. The lossy spatial impulse response is then evaluated in different spatial locations for four specific values of the power law exponent using several different values for the attenuation constant. As the attenuation constant or the distance from the source increases, the amplitude decreases while an increase in temporal broadening is observed. The sharp edges that appear in the time-limited lossless impulse response are replaced by increasingly smooth curves in the lossy impulse response, which decays slowly as a function of time.

A Rare Case of Erdheim-Chester Disease (Non-Langerhans Cell Histiocytosis) with Concurrent Langerhans Cell Histiocytosis: A Diagnostic and Therapeutic Challenge.

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocyte disorder most commonly characterized by multifocal osteosclerotic lesions of the long bones demonstrating sheets of foamy histiocyte infiltrates on biopsy with or without histiocytic infiltration of extraskeletal tissues. ECD can be difficult to diagnose since it is a very rare disease that can affect many organ systems. Diagnosis is based on the pathologic evaluation of involved tissue interpreted within the clinical context. Patients who have the BRAF V600E mutation are treated first line with vemurafenib. For those without the mutation with symptomatic ECD, conventional or PEGylated interferon alpha is recommended. For patients who are either intolerant or nonresponsive to interferon alpha, systemic chemotherapy with or without corticosteroids can be used. We present a rare case of Erdheim-Chester disease with concurrent Langerhans cell histiocytosis which occurs in only one fifth of the cases and often presents as a diagnostic and therapeutic challenge.

Primary Effusion Lymphoma without an Effusion: A Rare Case of Solid Extracavitary Variant of Primary Effusion Lymphoma in an HIV-Positive Patient.

Primary effusion lymphoma (PEL) is a unique form of non-Hodgkin lymphoma, usually seen in severely immunocompromised, HIV-positive patients. PEL is related to human herpesvirus-8 (HHV-8) infection, and it usually presents as a lymphomatous body cavity effusion in the absence of a solid tumor mass. There have been very few case reports of HIV-positive patients with HHV-8-positive solid tissue lymphomas not associated with an effusion (a solid variant of PEL). In the absence of effusion, establishing an accurate diagnosis can be challenging, and a careful review of morphology, immunophenotype, and presence of HHV-8 is necessary to differentiate from other subtypes of non-Hodgkin lymphoma. Treatment involves intensive chemotherapy, and prognosis is usually poor. We present a rare case of a PEL variant in an HIV-positive patient who presented with extensive lymphadenopathy without any associated effusions.

Can vestibular rehabilitation exercises help patients with concussion? A systematic review of efficacy, prescription and progression patterns.

OBJECTIVE: Concussion symptoms normally resolve within 7-10 days but vertigo, dizziness and balance dysfunction persist in 10-30% of cases causing significant morbidity. This study systematically evaluated the evidence supporting the efficacy, prescription and progression patterns of vestibular rehabilitation therapy (VRT) in patients with concussion. DESIGN: Systematic Review, guided by PRISMA guidelines and presenting a best evidence synthesis. DATA SOURCES: Electronic databases PubMed (1949 to May 2015), CINAHL (1982 to May 2015), EMBASE (1947 to May 2015), SPORTDiscus (1985 to May 2015), Web of Science (1945 to May 2015) and PEDRO (1999 to May 2015), supplemented by manual searches and grey literature. ELIGIBILITY CRITERIA FOR STUDY SELECTION: Article or abstract of original research, population of patients with concussion/mild traumatic brain injury (mTBI) with vestibular symptoms, interventions detailing VRT, measurement of outcomes pre-VRT/post-VRT. Study type was not specified. RESULTS: Following a double review of abstract and full-text articles, 10 studies met the inclusion criteria: randomised controlled trial (n=2), uncontrolled studies (n=3) and case studies (n=5). 4 studies evaluated VRT as a single intervention. 6 studies incorporated VRT in multimodal interventions (including manual therapy, strength training, occupational tasks, counselling or medication). 9 studies reported improvement in outcomes but level I evidence from only 1 study was found that demonstrated increased rates (OR 3.91; 95% CI 1.34 to 11.34; p=0.002) of medical clearance for return to sport within 8 weeks, when VRT (combined with cervical therapy) was compared with usual care. Heterogeneity in study type and outcomes precluded meta-analysis. Habituation and adaptation exercises were employed in 8 studies and balance exercises in 9 studies. Prescription and progression patterns lacked standardisation. CONCLUSIONS: Current evidence for optimal prescription and efficacy of VRT in patients with mTBI/concussion is limited. Available evidence, although weak, shows promise in this population. Further high-level studies evaluating the effects of VRT in patients with mTBI/concussion with vestibular and/or balance dysfunction are required.

Benefits Associated With Early Diagnosis and Treatment of Soft Tissue Sarcomas of the Foot and Ankle.

Soft tissue sarcomas arising in the foot and ankle are often misdiagnosed, resulting in excision without adequate preoperative staging or surgical margins. The goal of the present study was to review a case series of soft tissue sarcomas of the foot and ankle with attention directed at unplanned excisions of sarcomas. An unplanned excision means that a patient either underwent an inadequate preoperative workup or the preoperative workup indicated a benign entity, resulting in surgical resection. We retrospectively analyzed the medical records of 10 patients with sarcomas of the foot and ankle treated at our institution. All soft tissue sarcomas were excised with the widest margin possible without any major bone or neurovascular resection to allow for preservation of the foot. All patients were followed up for a minimum of 8 months to assess pain, function, and complications. The patients were followed up for an average of 22.4 (range 8 to 44) months. Of the 10 patients, 6 had undergone preoperative magnetic resonance imaging without contrast and the sarcomas were read as benign or cystic masses. Two patients had undergone preoperative magnetic resonance imaging with contrast, and these scans were also misread. Despite having undergone previous unplanned surgery, none of these sarcomas had recurred after repeat resection with a wider margin at a mean follow-up of 22.4 (range 8 to 44) months. At the last follow-up point, 8 patients were alive without evidence of disease. Minor complications included lymph edema in 1, stress fracture in 1, and wound infection in 1 that resolved. Preoperative MRI with contrast is recommended before resecting any soft tissue masses of the foot and ankle. In the event of an unplanned excision of a soft tissue sarcoma, the patient should be referred to an orthopedic oncologist for definitive surgery to optimize the oncologic and functional results. In the present retrospective analysis, previous intervention did not seem to affect the prognosis, including local recurrence, distant metastasis, disease-free interval, and functional outcomes.

Free tax assistance and the earned income tax credit: vital resources for social workers and low-income families.

As the United States' economy continues to experience challenges, more families at or near the poverty level fall prey to predatory financial practices. Their vulnerability to these operations is increased by a lack of knowledge of asset-building resources and alternative financial services. This article focuses on Volunteer Income Tax Assistance (VITA)--a free income tax preparation program, which is a vital resource available to low-income families. Unfortunately, VITA is largely underused and often unknown to economically strained families and to the social workers and other professionals to whom these families turn for assistance. This article concludes with policy and practice implications for social workers and other professionals engaged in providing services to financially vulnerable families.