151 research outputs found
Microwave Components with MEMS Switches
RF MEMS switches with metal-metal contacts are being developed for microwave applications where broadband, high linearity performance is required. These switches provide less than 0.2 dB insertion loss through 40 GHz. This paper describes the integration of these switches into selected microwave components such as reconfigurable antenna elements, tunable filters, switched delay lines, and SPDT switches. Microwave and millimeter wave measured results from these circuits are presented
Point-of-care ultrasound diagnosis of pediatric cholecystitis in the ED
Abstract Objective: The diagnosis of cholecystitis or biliary tract disease in children and adolescents is an uncommon occurrence in the emergency department and other acute care settings. Misdiagnosis and delays in diagnosing children with cholecystitis or biliary tract disease of up to months and years have been reported in the literature. We discuss the technique and potential utility of point-of-care ultrasound evaluation in a series of pediatric patients with suspected cholecystitis or biliary tract disease. Methods: We present a nonconsecutive case series of pediatric and adolescent patients with abdominal pain diagnosed with cholecystitis or biliary tract disease using point-of-care ultrasound. The published sonographic criteria is 3 mm or less for the upper limits of normal gallbladder wall thickness and is 3 mm or less for normal common bile duct diameter (measured from inner wall to inner wall) in children. Measurements above these limits were considered abnormal, in addition to the sonographic presence of gallstones, pericholecystic fluid, and a sonographic Murphy's sign. Results: Point-of care ultrasound screening detected 13 female pediatric patients with cholecystitis or biliary tract disease when the authors were on duty over a 5-year period. Diagnoses were confirmed by radiology imaging or at surgery and surgical pathology. Conclusions: Point-of-care ultrasound to detect pediatric cholecystitis or biliary tract disease may help avoid misdiagnosis or delays in diagnosis in children with abdominal pain
Photothermal optical coherence tomography in ex vivo human breast tissues using gold nanoshells
We demonstrate photothermal optical coherence tomography (OCT) imaging in highly scattering human breast tissue ex vivo. A 120 kHz axial scan rate, swept-source phase-sensitive OCT system at 1300 nm was used to detect phase changes induced by 830 nm photothermal excitation of gold nanoshells. Localized phase modulation was observed 300–600 μm deep in scattering tissue using an excitation power of only 22 mW at modulation frequencies up to 20 kHz. This technique enables integrated structural and molecular-targeted imaging for cancer markers using nanoshells.National Institutes of Health (U.S.) (Grant Number R01- CA75289-13)United States. Air Force Office of Scientific Research (Contract Number FA9550-07-1-0014)MFELP (Contract Number FA9550-07-1-0101)Natural Sciences and Engineering Research Council of Canada (NSERC) Heritage Scholarship FundCenter for Integration of Medicine and Innovative TechnologyNational Science council of Taiwan. Taiwan Merit Scholarshi
Transcatheter Arterial Chemoembolization Is a Feasible Palliative Locoregional Therapy for Breast Cancer Liver Metastases
Background. Liver metastases are common in advanced breast cancer. We sought to evaluate the role of transcatheter arterial chemoembolization (TACE) in breast cancer patients with hepatic metastases. Methods. A retrospective review of ten patients with breast cancer who were treated with TACE for unresectable liver metastases (1998–2008). Results. All patients, median age 46.5, had received prior systemic chemotherapies. Adriamycin was administered for 6, cisplatin/gemcitabine for 2, cisplatin for one and oxaliplatin for one patient. Median number of TACE cycles was 4. Kaplan Meier survival analysis showed an increase in median survival for patients who responded to treatment when compared to those who did not respond (24 vs 7 months, P = .02). Conclusions. This is one of the largest series of breast cancer patients with liver metastases treated with TACE. It suggests that TACE is a feasible palliative option and warrants further investigations
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
Higher body mass index may induce asthma among adolescents with pre-asthmatic symptoms: a prospective cohort study
<p>Abstract</p> <p>Background</p> <p>Limited studies have prospectively examined the role of body mass index (BMI) as a major risk factor for asthma during adolescence. This study investigates whether BMI is associated with increased risk of developing physician-diagnosed asthma during 12-month follow-up among adolescents with undiagnosed asthma-like symptoms at baseline.</p> <p>Methods</p> <p>A total of 4,052 adolescents with undiagnosed asthma-like symptoms at baseline were re-examined after a 12-month follow-up. Asthma cases were considered confirmed only after diagnosis by a physician based on the New England core and International Study of Asthma and Allergies in Childhood (ISAAC) criteria video questionnaires, and accompanying pulmonary function tests. Logistic regression analyses were used to evaluate the relationship of BMI and the risk of acquiring asthma.</p> <p>Results</p> <p>The results indicated that girls with higher BMI were at an increased risk of developing asthma during the 12-month follow-up. The odds ratios for girls developing physician-diagnosed asthma were 1.75 (95% CI = 1.18-2.61) and 1.12 (95% CI = 0.76-1.67), respectively, for overweight and obesity as compared to the normal weight reference group after adjustment for other covariates. A similar relationship was not observed for overweight and obese boys who were also significantly more active than their female counterparts.</p> <p>Conclusions</p> <p>Increased BMI exaggerates the risk of acquiring asthma in symptomatic adolescent females but not in adolescent males. Thus, gender is an important modifier of BMI-related asthma risk. Additional research will be required to determine whether the increased asthma risk results from genetic, physiological or behavioural differences.</p
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