Wireless Power Transfer to Biomedical Implants Using a Class-E Inverter and a Class-DE Rectifier

In this article, we propose a strategy for the design of a wireless power transfer system consisting of a class-E inverter, a half-bridge class-DE rectifier, and two coupled coils. The system is optimized for maximum power transfer efficiency. The design is validated via a case study, for which a wireless power transfer link to a neuroprosthesis was designed. After circuit simulations, a prototype was realized and measured. There is a good agreement between the calculated, simulated and measured voltages and currents. The prototype delivers 80 mW, 7 V to a biomedical implant at 6.78 MHz, the transfer efficiency is 52 to 68%, depending on the alignment. The end-to-end efficiency, with the controller and gate driver also taken into account, is 39 to 57%. Electromagnetic and thermal simulations were performed to verify compliance with relevant safety regulations on specific absorption rate (SAR) levels, magnetic field strength, and heat generation in the implant, for separation distances between the coils of 8 to 15 mm, and transverse misalignment from 0 to 15 mm.</p

Muscle Function in Moderate to Severe Asthma:Association With Clinical Outcomes and Inflammatory Markers

BackgroundPatients with severe asthma have been shown to have low muscle mass, but the clinical consequences are unknown.ObjectiveIn a clinical cohort of patients with moderate to severe asthma, we aimed to assess muscle mass and strength and their relation with functional and clinical outcomes, as well as with systemic inflammatory markers.MethodsMuscle mass and strength were assessed by the fat-free mass index (FFMI), creatinine excretion in a 24-hour urine sample, and handgrip strength test. Functional outcomes included pulmonary function tests and the 6-minute walking distance, whereas clinical outcomes were assessed with questionnaires on asthma control, quality of life, and health care use. Associations of muscle mass and strength with asthma outcomes were assessed with multivariable regression analyses.ResultsA total of 114 patients participated (36% male; mean age, 51.9 ± 14.4 years; body mass index, 27.7 ± 5.7 kg/m2). According to predefined criteria, 16% had a low FFMI and 8% a low urinary creatinine excretion, which did not differ between categories of asthma severity. Both lower FFMI and urinary creatinine excretion were associated with lower values of FEV1 and 6-minute walking distance, whereas a lower handgrip strength was related to worse asthma control, poorer quality of life, and a higher probability of emergency visits (all P &lt; .05). Except for higher leukocytes in relation to lower FFMI, we did not find associations between systemic inflammatory markers and muscle function.ConclusionsThis study demonstrates that low muscle mass is prevalent in patients with moderate to severe asthma and, along with low muscle strength, is associated with poorer clinical and functional outcomes. Our results encourage longitudinal studies into muscle function as a potential target for treatment to improve asthma outcomes

Modulation by epidermal growth factor of the basal 1,25(OH)2D3 receptor level and the heterologous up-regulation of the 1,25(OH)2D3 receptor in clonal osteoblast-like cells

The effects of epidermal growth factor (EGF) on basal 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) receptor level and on parathyroid hormone (PTH)-induced 1,25-(OH)2D3 (OH)2D3 receptor up-regulation were studied in the phenotypically osteoblastic cell line UMR 106. EGF in concentrations exceeding 0.1 ng/ml reduced the number of 1,25(OH)2D3 binding sites without changing the binding affinity. Maximal reduction was 30% at about 1 ng/ml. This reduction was independent of a change in cAMP content. EGF dose-dependently attenuated both PTH-induced 1,25(OH)2D3 receptor up-regulation and PTH-stimulated cAMP production without and effect on the ED50 of the PTH effects. For both PTH responses the IC50 and the maximal effective dose were similar, 0.1 ng/ml an 1 ng/ml EGF, respectively. Reduction was first seen at 0.01 ng/ml EGF. At this concentration. EGF reduced PTH-stimulated 1,25-(OH)2D3 receptor binding without an inhibition of the cAMP response. Time-course studies with 1 ng/ml EGF revealed that at 2 h preincubation EGF reduced the heterologous up regulation by PTH, and maximal inhibition was seen after 4 h. In contrast, PTH-stimulated cAMP production was just significantly inhibited only after 6 h, with 60% inhibition after 24 h preincubation. The effects of prostaglandin E2 and forskolin on both 1,25(OH)2D3 binding and cAMP production were inhibited in a similar fashion. On the other hand, dibutyryl cAMP- and 3-isobutyl-1-methylxanthinestimulated 1,25(OH)2D3 binding were not affected by EGF. Taken together, our results demonstrate that EGF reduces both the basal number of 1,25(OH)2D3 binding sites and the heterologous up-regulation of the 1,25(OH)2D3 receptor. The current data suggest that EGF reduces heterologous upregulation of the 1,25(OH)2D3 receptor independent of as well as dependent on the cAMP messenger system. The EGF effect is not primarily located at the PTH receptor, at cAMP phosphodiesterase, or at protein kinase A level

Subclinical hypothyroidism is an independent risk factor for atherosclerosis and myocardial infarction in elderly women: the Rotterdam Study

BACKGROUND: Overt hypothyroidism has been found to be associated with cardiovascular disease. Whether subclinical hypothyroidism and thyroid autoimmunity are also risk factors for cardiovascular disease is controversial. OBJECTIVE: To investigate whether subclinical hypothyroidism and thyroid autoimmunity are associated with aortic atherosclerosis and myocardial infarction in postmenopausal women. DESIGN: Population-based cross-sectional study. SETTING: A district of Rotterdam, The Netherlands. PARTICIPANTS: Random sample of 1149 women (mean age +/- SD, 69.0 +/- 7.5 years) participating in the Rotterdam Study. MEASUREMENTS: Data on thyroid status, aortic atherosclerosis, and history of myocardial infarction were obtained at baseline. Subclinical hypothyroidism was defined as an elevated thyroid-stimulating hormone level (>4.0 mU/L) and a normal serum free thyroxine level (11 to 25 pmol/L [0.9 to 1.9 ng/dL]). In tests for antibodies to thyroid peroxidase, a serum level greater than 10 IU/mL was considered a positive result. RESULTS: Subclinical hypothyroidism was present in 10.8% of participants and was associated with a greater age-adjusted prevalence of aortic atherosclerosis (odds ratio, 1.7 [95% CI, 1.1 to 2.6]) and myocardial infarction (odds ratio, 2.3 [CI, 1.3 to 4.0]). Additional adjustment for body mass index, total and high-density lipoprotein cholesterol level, blood pressure, and smoking status, as well as exclusion of women who took beta-blockers, did not affect these estimates. Associations were slightly stronger in women who had subclinical hypothyroidism and antibodies to thyroid peroxidase (odds ratio for aortic atherosclerosis, 1.9 [CI, 1.1 to 3.6]; odds ratio for myocardial infarction, 3.1 [CI, 1.5 to 6.3]). No association was found between thyroid autoimmunity itself an

Diet quality, food intake and incident adult-onset asthma:a Lifelines Cohort Study

PURPOSE: Dietary factors have been suggested as drivers of the rising prevalence of adult-onset asthma, but evidence is inconclusive, possibly due to the complex interrelation with obesity. We aim to explore the relation of diet quality and food intake with incident adult-onset asthma in normal weight and overweight adults of the prospective population-based Lifelines Cohort Study.METHODS: Incident adult-onset asthma was defined as self-reported asthma at ± 4-year follow-up, in adults free of airway disease at baseline. Diet quality scores and food group intake were assessed at baseline. Log-binomial regression analyses were used to estimate adjusted relative risks (RR) between dietary intake (per portion) and incident adult-onset asthma, in categories of BMI (cutoff: 25 kg/m 2). RESULTS: 477 incident asthma cases (75% female, 62% overweight) and 34,698 controls (60% female, 53% overweight) were identified. Diet quality-assessed by the Lifelines Diet Score and Mediterranean Diet Score-was not associated with incident adult-onset asthma in the two BMI groups. Although the dietary intake of several food groups differed between cases and controls, after adjustment for confounders only few remained associated with adult-onset asthma, including red and processed meat (RR: 0.93 per 15 g intake; 95% CI 0.86-0.99) in the normal weight group and intake of cheese (RR 1.09 per 20 g intake; 95% CI 1.00-1.17) and vegetables (RR 1.10 per 50 g intake; 95% CI 1.00-1.21) in the overweight group.CONCLUSION: The results of this study question the role of food as a 'simple' predictor of adult-onset asthma and call for an integrative approach, including a range of modifiable lifestyle factors and further asthma phenotyping.</p

Fibrinolysis during liver transplantation is enhanced by using solvent/detergent virus-inactivated plasma (ESDEP)

After the introduction of solvent/detergent-treated plasma (ESDEP) in our hospital, an increased incidence of hyperfibrinolysis was observed (75% vs 29%; P = 0.005) compared with the use of fresh frozen plasma for liver transplantation. To clarify this increased incidence, intraoperative plasma samples of patients treated with fresh frozen plasma or ESDEP were analyzed in a retrospective observational study. During the anhepatic phase, plasma levels of D-dimer (6.58 vs 1.53 microg/mL; P = 0.02) and fibrinogen degradation products (60 vs 23 mg/L; P = 0.018) were significantly higher in patients treated with ESDEP. After reperfusion, differences increased to 23.5 vs 4.7 microg/mL (D-dimer, P = 0.002) and 161 vs 57 mg/L (fibrinogen degradation products, P = 0.001). The amount of plasma received per packed red blood cell concentrate, clotting tests, and levels of individual clotting factors did not show significant differences between the groups. alpha(2)-Antiplasmin levels, however, were significantly lower in patients receiving ESDEP during the anhepatic phase (0.37 vs 0.65 IU/mL; P < 0.001) and after reperfusion (0.27 vs 0.58 IU/mL; P = 0.001). Analysis of alpha(2)-antiplasmin levels in ESDEP alone showed a reduction to 0.28 IU/mL (normal >0.95 IU/mL) because of the solvent/detergent process. Therapeutic consequences for the use of ESDEP in orthotopic liver transplantation are discussed in view of an increased incidence of hyperfibrinolysis caused by reduced levels of alpha(2)-antiplasmin in the solvent/detergent-treated plasma. IMPLICATIONS: The use of solvent/detergent virus-inactivated plasma is of increasing importance in the prevention of human immunodeficiency virus and hepatitis C virus transmission. Since the use of this plasma during orthotopic liver transplantation has increased, the incidence of hyperfibrinolysis was observed. Clotting analysis of the patients revealed small alpha(2)-antiplasmin concentrations because of the solvent/detergent process

The Features of the Synovium in Early Rheumatoid Arthritis According to the 2010 ACR/EULAR Classification Criteria

OBJECTIVES: It has been shown in early arthritis cohorts that the 2010 ACR/EULAR criteria for rheumatoid arthritis (RA) enable an earlier diagnosis, perhaps at the cost of a somewhat more heterogeneous patient population. We describe the features of synovial inflammation in RA patients classified according to these new criteria. METHODS: At baseline, synovial tissue biopsy samples were obtained from disease-modifying antirheumatic drug (DMARD)-naïve early RA patients (clinical signs and symptoms <1 year). Synovial tissue was analyzed for cell infiltration, vascularity, and expression of adhesion molecules. Stained sections were evaluated by digital image analysis. Patients were classified according to the two different sets of classification criteria, autoantibody status, and outcome. FINDINGS: Synovial tissue of 69 RA patients according to 2010 ACR/EULAR criteria was analyzed: 56 patients who fulfilled the criteria for RA at baseline and 13 who were initially diagnosed as undifferentiated arthritis but fulfilled criteria for RA upon follow up. The synovium at baseline was infiltrated by plasma cells, macrophages, and T cells as well as other cells, and findings were comparable to those when patients were selected based on the 1987 ACR criteria for RA. There was no clear cut difference in the characteristics of the synovium between RA patients initially diagnosed as undifferentiated arthritis and those who already fulfilled classification criteria at baseline. CONCLUSION: The features of synovial inflammation are similar when the 2010 ACR/EULAR classification criteria are used compared to the 1987 ACR criteria

The Herschel-Heterodyne Instrument for the Far-Infrared (HIFI): instrument and pre-launch testing

This paper describes the Heterodyne Instrument for the Far-Infrared (HIFI), to be launched onboard of ESA's Herschel Space Observatory, by 2008. It includes the first results from the instrument level tests. The instrument is designed to be electronically tuneable over a wide and continuous frequency range in the Far Infrared, with velocity resolutions better than 0.1 km/s with a high sensitivity. This will enable detailed investigations of a wide variety of astronomical sources, ranging from solar system objects, star formation regions to nuclei of galaxies. The instrument comprises 5 frequency bands covering 480-1150 GHz with SIS mixers and a sixth dual frequency band, for the 1410-1910 GHz range, with Hot Electron Bolometer Mixers (HEB). The Local Oscillator (LO) subsystem consists of a dedicated Ka-band synthesizer followed by 7 times 2 chains of frequency multipliers, 2 chains for each frequency band. A pair of Auto-Correlators and a pair of Acousto-Optic spectrometers process the two IF signals from the dual-polarization front-ends to provide instantaneous frequency coverage of 4 GHz, with a set of resolutions (140 kHz to 1 MHz), better than < 0.1 km/s. After a successful qualification program, the flight instrument was delivered and entered the testing phase at satellite level. We will also report on the pre-flight test and calibration results together with the expected in-flight performance

Equivalent length design equations for right-angled microstrip bends

For printed antenna systems, microstrip feeding networks may become quite complex, including several right-angled bends. In designing feed networks we have to consider reflection levels at and electrical lengths of the bends. Removing a part of the area of metallization in the bend's corner can compensate for the excess capacitance and reduce the reflection level of the bend. Full wave simulations have been performed for unmitered and (50%) mitered right-angled bends in microstrip on FR4 and FR4 -like substrates in the frequency range 868MHz - 60GHz. The simulations revealed that for reflection levels below -15dB, up to 10GHz mitering is unnecessary. For reflection levels below -20dB, mitering must be applied for frequencies in excess of 2.5GHz. A slight modification of the centreline approach for unmitered bends leads to an equivalent electrical length for unmitered bends with an absolute accuracy of less than one degree for all frequencies and substrates, where the reference planes may be brought back all the way to the bend. Applying this modification to 50%-mitered bends, having the reference planes at 0.2 lambdag distance from the bend, lambdag being the wavelength in the substrate, leads to an absolute error in electrical length of less than two and a half degrees for all frequencies and substrates