Optimization of Time- and Code-Division-Multiplexed Readout for Athena X-IFU.

Readout of a large, spacecraft-based array of superconducting transition-edge sensors (TESs) requires careful management of the layout area and power dissipation of the cryogenic-circuit components. We present three optimizations of our time- (TDM) and code-division-multiplexing (CDM) systems for the X-ray Integral Field Unit (X-IFU), a several-thousand-pixel-TES array for the planned Athena-satellite mission. The first optimization is a new readout scheme that is a hybrid of CDM and TDM. This C/TDM architecture balances CDM's noise advantage with TDM's layout compactness. The second is a redesign of a component: the shunt resistor that provides a dc-voltage bias to the TESs. A new layout and a thicker Pd-Au resistive layer combine to reduce this resistor's area by more than a factor of 5. Third, we have studied the power dissipated by the first-stage SQUIDs (superconducting quantum-interference devices) and the readout noise versus the critical current of the first-stage SqUIDs. As a result, the X-IFU TDM and C/TDM SQUIDs will have a specified junction critical current of 5 µA. Based on these design optimizations and TDM experiments described by Durkin, et al. (these proceedings), TDM meets all requirements to be X-IFU's backup-readout option. Hybrid C/TDM is another viable option that could save spacecraft resources.

Demonstration of Athena X-IFU Compatible 40-Row Time-Division-Multiplexed Readout.

Time-division multiplexing (TDM) is the backup readout technology for the X-ray Integral Field Unit (X-IFU), a 3,168-pixel X-ray transition-edge sensor (TES) array that will provide imaging spectroscopy for ESA's Athena satellite mission. X-0IFU design studies are considering readout with a multiplexing factor of up to 40. We present data showing 40-row TDM readout (32 TES rows + 8 repeats of the last row) of TESs that are of the same type as those being planned for X-IFU, using measurement and analysis parameters within the ranges specified for X-IFU. Singlecolumn TDM measurements have best-fit energy resolution of (1.91 ± 0.01) eV for the Al Kα complex (1.5 keV), (2.10 ± 0.02) eV for Ti Kα (4.5 keV), (2.23 ± 0.02) eV for Mn Kα (5.9 keV), (2.40 ± 0.02) eV for Co Kα (6.9 keV), and (3.44 ± 0.04) eV for Br Kα (11.9 keV). Three-column measurements have best-fit resolution of (2.03 ± 0.01) eV for Ti Kα and (2.40 ± 0.01) eV for Co Kα. The degradation due to the multiplexed readout ranges from 0.1 eV at the lower end of the energy range to 0.5 eV at the higher end. The demonstrated performance meets X-IFU's energy-resolution and energy-range requirements. True 40-row TDM readout, without repeated rows, of kilopixel scale arrays of X-IFU-like TESs is now under development.

Antineuronal nuclei immunohistochemical staining patterns in childhood ependymomas.

NeuN, the mouse-derived monoclonal antibody to the reportedly neuron-specific nuclear protein, has been observed to react with many different types of normal, postmitotic neurons throughout the central and peripheral nervous systems. We retrospectively examined 23 surgical specimens (collected from 20 patients) originally diagnosed at our institution between 1983 and 1999 as ependymoma (9), myxopapillary ependymoma (1), anaplastic/malignant ependymoma (10), and primitive neuroectodermal tumor with ependymal differentiation (3). The ependymomas included lesions from the spine (3), cerebrum (5), and posterior fossa (15). Representative formalin-fixed, paraffin-embedded sections from each tumor were subjected to immunohistochemical staining with antibody against NeuN (Chemicon International, Inc, Temecula, CA). Five astrocytomas, four primitive neuroectodermal tumors, and normal cerebral cortex and ependyma from autopsy brains of premature newborns, term infants, and older children served as controls. Thirteen ependymal tumors had positive nuclear staining ranging from rare tumor cells to numerous groups of cells; of these, 9 were anaplastic ependymomas and had the most staining. These studies suggest that some ependymomas arise from a pluripotential neuroglial cell.

Exploration of the perspectives of persons with schizophrenia regarding quality of life.

OBJECTIVE: This study is the first phase of a two-phase study aimed at exploring the perspectives of consumers with schizophrenia regarding quality of life and developing a quality-of-life assessment that addresses factors experienced as important by consumers. METHOD: Focus groups were used to explore the perspectives of 35 persons with schizophrenia regarding the meaning of quality of life and factors important to quality of life. RESULTS: Seven major factors that had an impact on quality of life resulted from inductive analysis, including activity, social interaction, time, disclosure, "being normal," finances, and management of illness. These factors relate to three overall themes: managing time, connecting and belonging, and making choices and maintaining control. CONCLUSIONS: Although the findings confirm the importance of factors included in existing quality-of-life assessments, they also highlight the need to look at new dimensions of commonly included factors and to include other factors. The findings support beliefs regarding occupation that are central to occupational therapy and the use of occupation as means and ends of therapy.

Advances in pediatric airway radiology.

Radiologic evaluation of the airway has been used as a screening tool and an adjunct to endoscopy for many years. It provides noninvasive data on the structure of the airway while avoiding the risk of general anesthesia. In the past, standard radiographs provided only a shadow of the intricate anatomy of the pediatric airway. Not only have there been advances in static imaging but there now exists technology that enable noninvasive dynamic imaging and new techniques for image-guided intervention within the airway. This article focuses on four specific areas: airway fluoroscopy, functional swallow studies, controlled ventilation computed tomography, and interventional airway techniques.

Exploration of a group model in fieldwork education.

OBJECTIVE: Organizational changes, such as program management and managed care, and fluctuations in resources present challenges to the effective provision of fieldwork placements. This study compared an innovative group model with a traditional 1:1 supervision model to determine their effect on students and supervisors. METHOD: The two models were implemented at an urban clinical facility in several areas of practice over a 2 year period. Questionnaires were used to assess student skill development, student and supervising therapist satisfaction, and impact on supervising therapists' use of time. Focus groups were used to explore the advantages and disadvantages of each model. RESULTS: There were few statistically significant differences in students' (n = 26) and supervising therapists' (n = 28) ratings when the two models were compared. The qualitative findings suggest that the advantages of one model often relate to the disadvantages of the other model. In addition, supervising therapists and students offered several suggestions for how to improve implementation of the group model. CONCLUSION: When the results of the study are compared to the objectives established for the group model, it appears that many of the objectives outlined for the model were partially achieved. Several issues, such as the student-supervisor relationship and the evaluation process, need to be addressed with participants to ensure successful implementation of the group model.

Herpetic tracheitis and brachial plexus neuropathy in a child with burns.

Herpetic tracheobronchitis is a well-recognized clinical entity that most commonly occurs in immunocompromised patients, including patients with burns. Although the diagnosis of herpetic tracheobronchitis is usually not made until postmortem examination, the presence of the condition can be established when histologic specimens of a patient with upper airway obstruction are studied. In this article, a case is described in which a child developed herpetic tracheitis after undergoing elective intubation after the grafting of burns of the face, neck, and upper extremity. The tracheitis resulted in severe upper airway obstruction that required tracheal dilatation and sequential bronchoscopic excisions of granulation tissue. The patient also developed a brachial plexus neuropathy that was most likely related to herpetic infection.

Description and validation of a measure of received support specific to HIV.

Validation data are described for the Social Support Inventory for People who are HIV Positive or Have AIDS. This inventory was developed specifically for use with individuals who are HIV-positive to assess three types of received support (instrumental, informational, emotional) for each of four dimensions: whether support is received or wanted, satisfaction with support, and source of the support. It was validated in the context of a larger cross-sectional study of 120 adults with HIV who completed a set of questionnaires. Descriptive statistics, internal consistency coefficients, and evidence of construct validity for the original inventory are presented. An improved, revised version based on the validation data for the original one is also briefly described, but not tested.

Intracortical chondroma.

A case of a 45-year-old woman with an intracortical chondroma of the right tibia is described. The uniqueness of this location and presentation is discussed.

An instrument evaluation framework: description and application to assessments of hand function.

An instrument evaluation framework outlining a process for selecting measurement instruments for use in hand therapy is presented. Each section of the framework--including clinical utility, standardization, purpose, psychometric properties, and patient's perspective--is explained in detail. The framework is applied to four hand function assessments that measure functional limitation, specifically, the Test Evaluant les Membres Supèrieurs des Personnes Agèes (Upper Extremity Performance Evaluation Test for the Elderly; TEMPA), the Jebsen Test of Hand Function, the Smith Hand Function Test, and the Quantitative Test of Upper Extremity Function. The therapists who developed and applied the framework selected the TEMPA as the most appropriate measure for their setting. This framework will assist hand therapists in justifying the selection of measurement instruments and will facilitate a consistent, comprehensive, and critical evaluation approach.

Functional endoscopic sinus surgery training simulator.

OBJECTIVE/HYPOTHESIS: To determine the efficacy of a haptic (force feedback) device and to compare isosurface and volumetric models of a functional endoscopic sinus surgery (FESS) training simulator. STUDY DESIGN: A pilot study involving faculty and residents from the Department of Otolaryngology at The Ohio State University. METHODS: Objective trials evaluated the haptic device's ability to perceive three-dimensional shapes (stereognosis) without the aid of image visualization. Ethmoidectomy tasks were performed with both isosurface and volumetric FESS simulators, and surveys compared the two models. RESULTS: The haptic device was 77% effective for stereognosis tasks. There was a preference toward the isosurface model over the volumetric model in terms of visual representation, comfort, haptic-visual fidelity, and overall performance. CONCLUSIONS: The FESS simulator uses both visual and haptic feedback to create a virtual reality environment to teach paranasal sinus anatomy and basic endoscopic sinus surgery techniques to ear, nose, and throat residents. The results of the current study showed that the haptic device was accurate in and of itself, within its current physical limitations, and that the isosurface-based simulator was preferred.

Understanding the potential of occupation: a qualitative exploration of seniors' perspectives on activity.

This article presents the results of a qualitative study that explored the characteristics and potential of occupation. Semistructured interviews with 12 seniors who live in the community followed by member-checking groups were used to explore informants' perspectives on the importance and role of occupation in their lives by asking them about their activities. Themes pertinent to the characterization of activity, the contributions of activity, and a condition allowing for the potential of activity emerged from the inductive analysis. These themes provide information about how occupation naturally functions in the lives of seniors and suggest a tentative conceptualization of the characteristics and potential of occupation. The findings have implications for research regarding occupation and for clinical practice aimed at enabling occupation.

Long-term outcome analysis of functional endoscopic sinus surgery: correlation of symptoms with endoscopic examination findings and potential prognostic variables.

One hundred eighty-two patients were evaluated after functional endoscopic sinus surgery. The goal was to establish whether any anatomical finding correlated with symptoms and to find any historical predictors of symptomatic failure. Of all physical findings reviewed, only scarring of middle meatal antrostomy and scarring of the ethmoids approached significance in predicting poor outcome. Surprisingly, of the historical factors reviewed, only gastroesophageal reflux disease was statistically significant as a predictor of poor symptomatic outcome.

Serum insulin-like growth factor-I and serum testosterone status of elderly men in an inpatient rehabilitation unit.

This study was designed to estimate the prevalence of hyposomatomedinemia and hypogonadism in an inpatient rehabilitation unit. The authors studied healthy young men (HOM) ages 20-29 years (n=33); healthy old men (HOM) ages 59-98 years (n=27), and elderly men in an inpatient rehabilitation unit (ERM) ages 58-95 years (n=42). Serum concentrations of insulin-like growth factor (IGF-I), total testosterone (TT), and free testosterone (FT) were measured. A low IGF-I level (below the lower 2.5 percentile of HYM) occurred in 85% of the HOM and in 62.5% of the ERM. When a low IGF-I was defined as a value below the 2.5 percentile of the HOM, the prevalence in ERM was 6.2%. A low TT level (below the lower 2.5 percentile of the HOM) occurred in 78% of the HOM and in 90% of the ERM. Low TT, defined as a value below the lower 2.5 percentile of the HOM, occurred in 22% of the ERM. The results with FT were similar. In neither HOM nor ERM was IGF-I significantly correlated to TT and FT. A large percentage of HOM and ERM have severe hypogonadism (TT<193 ng/mL) as compared with HOM. The ERM had a higher prevalence of severe hypogonadism as compared with the HOM.

Observations on nursing home residents with a history of hip fracture.

The authors evaluated nursing home residents with a prior history of hip fracture for osteopenia and its risk factors, and attempted to learn to what extent the residents' bone status had been considered by their primary care physicians. Thirty-one hip fracture residents in the Milwaukee VA nursing home were studied to determine their status with regard to bone mineral density of the proximal femur, and the following risk factors or predictors of osteopenia: history of smoking; history of fractures; calcium and vitamin D intake; underweight; immobility; hypogonadism; and administration of drugs that may accelerate bone demineralization. Data were also collected on the evaluation and management of the post hip fracture residents in three other nursing homes. In the Milwaukee nursing home, out of 31 hip fracture survivors, 74% had sustained a hip fracture before admission to the nursing home; 29% had a history of second fracture. In 84% of patients, there was no mention of osteopenia in the active medical problem list and, therefore, there was no intervention plan in place to improve or prevent further bone loss. Thirty-two percent were underweight, 36% were currently smoking, 55% were immobile, 64% were consuming at least one medication that might increase bone loss, calcium intake was less than 1,000 mg daily in 52%, and 66% were hypogonadal (serum testosterone level less than 300 ng/dL). Chart reviews of the hip fracture survivors at three other nursing homes revealed similar findings. Approximately 5-15% of nursing home residents are hip fracture survivors. They usually have severe osteopenia and multiple risk factors for further bone loss and future fractures.(ABSTRACT TRUNCATED AT 250 WORDS)

Observations on the nutrient intakes of eating-dependent nursing home residents: underutilization of micronutrient supplements.

OBJECTIVE: To estimate the intakes of essential nutrients by eating-dependent nursing home residents (EDR). METHODS: This study was done in a 190 bed VA nursing home. Thirty-four EDR were selected for the study. Clinical data base which included age, sex, primary diagnosis, body mass index, albumin, hematocrit, activities of daily living status, decubitus ulcer medications and use of multivitamin/trace mineral supplement were recorded from the medical records. Caloric and essential nutrient intakes were determined over a 3-day period by a registered dietitian. RESULTS: Seventy percent (24/34) residents in the study group were underweight (body mass index < 23 kg/m2), 26% were hypoalbuminemic (serum level < 3.5 g/dl), 50% were anemic (hematocrit < 37%); and 38% had pressure ulcers. In 88% EDR, the dietary intakes of three or more essential nutrients were below 50% of the RDA. Most frequent and severely deficient were zinc, copper, and vitamin B6. Despite the inadequate essential micronutrient intakes in the majority of EDR, only 35% received a multivitamin supplement and only 3% received a trace mineral supplement. A survey of 30 other VA nursing homes indicated generally similar findings to those in the Milwaukee facility with regard to the high frequency for eating-dependence, and the low frequency for administration of multivitamin and trace mineral supplements. CONCLUSIONS: Despite eating supervision and assistance, the majority of EDR have inadequate intakes of numerous essential macro- and micronutrients. The deficient micronutrient intakes could be normalized by administration of a multivitamin/trace mineral supplement daily. Nevertheless, only a minority of EDR in VA nursing homes currently receive such a supplement.

Studies of growth hormone/insulin-like growth factor-I in polio survivors.

In the later years of life, many polio survivors develop post-polio syndrome manifested by progressive muscular weakness. Previous work by the authors showed low IGF-I level in polio survivors compared to age-matched controls. IGF-I concentration tended to be lower in polio survivors who were older, male, obese, and also in persons experiencing difficulty in the activities of daily living which were independent of other factors. IGF-I levels did not correlate with the subjective report of recent decline in functional status. Further studies of nocturnal GH secretion indicated that low IGF-I level was secondary to impaired growth hormone secretion. Low IGF-I levels in subjects with post-polio syndrome were corrected by physiologic doses of hGH and the response was dose dependent. Lesser dosage was required to normalize IGF-I level compared to standard dosages previously used in younger persons. Inasmuch as low IGF-I level resulting from GH deficiency is known to be associated with weakness, muscle atrophy, and decrease in aerobic work capacity, it is postulated that low IGF-I levels that occur in aging polio survivors may have an adverse effect on their neuromuscular function, and that hGH replacement may improve their functional status. Moreover, the new dose-response data may decrease the frequency of side effects in future hGH treatment of older adults.