406 research outputs found

    Gold Deposits of the CIS

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    Secondary Electron Emission from Niobium at Cryogenic Temperatures

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    ā€¢ A Secondary Electron Emission test stand has been designed to study the initial conditions of secondary electrons emitted from niobium in cryogenic state. ā€¢ Secondary electron particle distributions have been studied for 0o, 15o, and 30o beveled surfaces ā€¢ BCP and EP samples have been compared showing that the EP count is over twice as large as the BCP count ā€¢ Electron beam surface conditioning was examined. Conditioning appears to be sensitive to pulse duration and the number of impacts ā€¢ Good comparison have been shown between experiment and simulatio

    Multichip imager with improved optical performance near the butt region

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    A compound imager consists of two or more individual chips, each with at least one line array of sensors thereupon. Each chip has a glass support plate attached to the side from which light reaches the line arrays. The chips are butted together end-to-end to make large line arrays of sensors. Because of imperfections in cutting, the butted surfaces define a gap. Light entering in the region of the gap is either lost or falls on an individual imager other than the one for which it is intended. This results in vignetting and/or crosstalk near the butted region. The gap is filled with an epoxy resin or other similar material which, when hardened, has an index of referaction near that of the glass support plate

    Simultaneous bilateral or unilateral carpal tunnel release? A prospective cohort study of early outcomes and limitations

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    BACKGROUND: Over 60% of patients with carpal tunnel syndrome present with symptoms and findings of nerve compression in both hands. Our goal was to compare patient-rated difficulties in performing activities of daily living in the early postoperative period between those undergoing bilateral carpal tunnel release and those undergoing unilateral carpal tunnel release. METHODS: This prospective cohort study enrolled consecutive patients with bilateral carpal tunnel syndrome undergoing bilateral carpal tunnel release (n = 47) or unilateral carpal tunnel release (n = 41). Patient function and disease severity were measured by an abbreviated form of the Disabilities of the Arm, Shoulder and Hand questionnaire, QuickDASH, and the Boston Carpal Tunnel Questionnaire at baseline, at postoperative visit 1 at a mean time (and standard deviation) of 10 Ā± 3 days, and at postoperative visit 2 at a mean time (and standard deviation) of 30 Ā± 6 days. Patients rated their difficulty in completing fifteen activities of daily living each day for the first postoperative week. Patients reported the factors that influenced their choice of surgery. RESULTS: There was no difference in baseline function or disease severity between the two groups with regard to QuickDASH and the Boston Carpal Tunnel Questionnaire. Patients in both groups improved after carpal tunnel release with no difference between groups either at postoperative visit 1 for QuickDASH (p = 0.97) and the Boston Carpal Tunnel Questionnaire (p = 0.86) or at postoperative visit 2 for QuickDASH (p = 0.43) and the Boston Carpal Tunnel Questionnaire (p = 0.34). Patients undergoing bilateral carpal tunnel release had more difficulty only during postoperative days 1 to 2 in opening jars (p = 0.03), cooking (p = 0.008), and doing household chores (p = 0.02). Patients in the two groups did not differ (p > 0.05) in their abilities to perform activities of daily living necessary for personal hygiene or independence on any day during the first seven days following surgery with regard to using the bathroom, bathing, dressing, or eating. Although the most common reason why patients chose bilateral carpal tunnel release was to avoid two surgical procedures (42%), the most common reason why patients chose unilateral carpal tunnel release was concern for self-care (36%). CONCLUSIONS: Patients with bilateral carpal tunnel syndrome can anticipate more severe functional impairment during the first few postoperative days with bilateral carpal tunnel release compared with unilateral carpal tunnel release, but limitations beyond postoperative day 2 or 3 are similar for bilateral and unilateral carpal tunnel release. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence

    The influence of insurance status on access to and utilization of a tertiary hand surgery referral center

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    BACKGROUND: The purpose of this study was to systematically examine the impact of insurance status on access to and utilization of elective specialty hand surgical care. We hypothesized that patients with Medicaid insurance or those without insurance would have greater difficulty accessing care both in obtaining local surgical care and in reaching a tertiary center for appointments. METHODS: This retrospective cohort study included all new patients with orthopaedic hand problems (n = 3988) at a tertiary center in a twelve-month period. Patient insurance status was categorized and clinical complexity was quantified on an ordinal scale. The relationships of insurance status, clinical complexity, and distance traveled to appointments were quantified by means of statistical analysis. An assessment of barriers to accessing care stratified with regard to insurance status was completed through a survey of primary care physicians and an analysis of both patient arrival rates and operative rates at our tertiary center. RESULTS: Increasing clinical complexity significantly correlated (p < 0.001) with increasing driving distance to the appointment. Patients with Medicaid insurance were significantly less likely (p < 0.001) to present with problems of simple clinical complexity than patients with Medicare and those with private insurance. Primary care physicians reported that 62% of local surgeons accepted patients with Medicaid insurance and 100% of local surgeons accepted patients with private insurance. Forty-four percent of these primary care physicians reported that, if patients who were underinsured (i.e., patients with Medicaid insurance or no insurance) had been refused by community surgeons, they were unable to drive to our tertiary center because of limited personal resources. Patients with Medicaid insurance (26%) were significantly more likely (p < 0.001) to fail to arrive for appointments than patients with private insurance (11%), with no-show rates increasing with the greater distance required to reach the tertiary center. CONCLUSIONS: Economically disadvantaged patients face barriers to accessing specialty surgical care. Among patients with Medicaid coverage or no insurance, local surgical care is less likely to be offered and yet personal resources may limit a patientā€™s ability to reach distant centers for non-emergency care. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence

    Synchronous clear cell renal cell carcinoma and tubulocystic carcinoma: genetic evidence of independent ontogenesis and implications of chromosomal imbalances in tumor progression

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    Seven percent of renal cell carcinoma (RCC) cases are diagnosed as "unclassified" RCC by morphology. Genetic profiling of RCCs helps define renal tumor subtypes, especially in cases where morphologic diagnosis is inconclusive. This report describes a patient with synchronous clear cell RCC (ccRCC) and a tubulocystic renal carcinoma (TCRC) in the same kidney, and discusses the pathologic features and genetic profile of both tumors. A 67 year-old male underwent CT scans for an unrelated medical event. Two incidental renal lesions were found and ultimately removed by radical nephrectomy. The smaller lesion had multiple small cystic spaces lined by hobnail cells with high nuclear grade separated by fibrous stroma. This morphology and the expression of proximal (CD10, AMACR) and distal tubule cell (CK19) markers by immunohistochemistry supported the diagnosis of TCRC. The larger lesion was a typical ccRCC, with Fuhrman's nuclear grade 3 and confined to the kidney. Molecular characterization of both neoplasms using virtual karyotyping was performed to assess relatedness of these tumors. Low grade areas (Fuhrman grade 2) of the ccRCC showed loss of 3p and gains in chromosomes 5 and 7, whereas oncocytic areas displayed additional gain of 2p and loss of 10q; the high grade areas (Fuhrman grade 3) showed several additional imbalances. In contrast, the TCRC demonstrated a distinct profile with gains of chromosomes 8 and 17 and loss of 9. In conclusion, ccRCC and TCRC show distinct genomic copy number profiles and chromosomal imbalances in TCRC might be implicated in the pathogenesis of this tumor. Second, the presence of a ccRCC with varying degrees of differentiation exemplifies the sequence of chromosomal imbalances acquired during tumor progression

    Sexual Functioning Among Endometrial Cancer Patients Treated With Adjuvant High-Dose-Rate Intra-Vaginal Radiation Therapy

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    Purposeā€”We used the Female Sexual Function Index (FSFI) to investigate the prevalence of sexual dysfunction (SD) and factors associated with diminished sexual functioning in early stage endometrial cancer (EC) patients treated with simple hysterectomy and adjuvant brachytherapy. Methods and Materialsā€”A cohort of 104 patients followed in a radiation oncology clinic completed questionnaires to quantify current levels of sexual functioning. The time interval between hysterectomy and questionnaire completion ranged from 5 years. Multivariate regression was performed using the FSFI as a continuous variable (score range, 1.2ā€“35.4). SD was defined as an FSFI score of <26, based on the published validation study. Resultsā€”SD was reported by 81% of respondents. The mean (Ā±standard deviation) domain scores in order of highest-to-lowest functioning were: satisfaction, 2.9 (Ā±2.0); orgasm, 2.5 (Ā±2.4); desire, 2.4 (Ā±1.3); arousal, 2.2 (Ā±2.0); dryness, 2.1 (Ā±2.1); and pain, 1.9 (Ā±2.3). Compared to the index population in which the FSFI cut-score was validated (healthy women ages 18ā€“74), all scores were low. Compared to published scores of a postmenopausal population, scores were not statistically different. Multivariate analysis isolated factors associated with lower FSFI scores, including having laparotomy as opposed to minimally invasive surgery (effect size, āˆ’7.1 points; 95% CI, āˆ’11.2 to āˆ’3.1; P<.001), lack of vaginal lubricant use (effect size, āˆ’4.4 points; 95% CI, āˆ’8.7 to āˆ’0.2, P = .040), and short time interval (<6 months) from hysterectomy to questionnaire completion (effect size, āˆ’4.6 points; 95% CI, āˆ’9.3ā€“0.2; P = .059). Conclusionsā€”The rate of SD, as defined by an FSFI score <26, was prevalent. The postmenopausal status of EC patients alone is a known risk factor for SD. Additional factors associated with poor sexual functioning following treatment for EC included receipt of laparotomy and lack of vaginal lubricant use

    Disruption of cholinergic neurotransmission, within a cognitive challenge paradigm, is indicative of AĪ²-related cognitive impairment in preclinical Alzheimerā€™s disease after a 27-month delay interval

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    Background Abnormal beta-amyloid (AĪ²) is associated with deleterious changes in central cholinergic tone in the very early stages of Alzheimerā€™s disease (AD), which may be unmasked by a cholinergic antagonist (J Prev Alzheimers Dis 1:1ā€“4, 2017). Previously, we established the scopolamine challenge test (SCT) as a ā€œcognitive stress testā€ screening measure to identify individuals at risk for AD (Alzheimerā€™s & Dementia 10(2):262ā€“7, 2014) (Neurobiol. Aging 36(10):2709-15, 2015). Here we aim to demonstrate the potential of the SCT as an indicator of cognitive change and neocortical amyloid aggregation after a 27-month follow-up interval. Methods Older adults (Nā€‰=ā€‰63, aged 55ā€“75ā€‰years) with self-reported memory difficulties and first-degree family history of AD completed the SCT and PET amyloid imaging at baseline and were then seen for cognitive testing at 9, 18, and 27 months post-baseline. Repeat PET amyloid imaging was completed at the time of the 27-month exam. Results Significant differences in both cognitive performance and in AĪ² neocortical burden were observed between participants who either failed vs. passed the SCT at baseline, after a 27-month follow-up period. Conclusions Cognitive response to the SCT (Alzheimerā€™s & Dementia 10(2):262ā€“7, 2014) at baseline is related to cognitive change and PET amyloid imaging results, over the course of 27ā€‰months, in preclinical AD. The SCT may be a clinically useful screening tool to identify individuals who are more likely to both have positive evidence of amyloidosis on PET imaging and to show measurable cognitive decline over several years
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