329 research outputs found
Near-field optical power transmission of dipole nano-antennas
Nano-antennas in functional plasmonic applications require high near-field optical power transmission. In this study, a model is developed to compute the near-field optical power transmission in the vicinity of a nano-antenna.
To increase the near-field optical power transmission from a nano-antenna, a tightly focused beam of light is utilized to illuminate a metallic nano-antenna. The modeling and simulation of these structures is performed using 3-D finite element method based full-wave solutions of Maxwell’s equations. Using the optical power transmission model, the interaction of a focused beam of light with plasmonic nanoantennas is investigated. In addition, the tightly focused beam of light is passed through a band-pass filter to identify the effect of various regions of the angular spectrum to the near-field radiation of a dipole nano-antenna. An extensive parametric study is performed to quantify the effects of various parameters on the transmission efficiency of dipole nano-antennas, including length, thickness, width, and the composition of the antenna, as well as the wavelength and half-beam angle of incident light. An optimal dipole nanoantenna geometry is identified based on the parameter studies in this work. In addition, the results of this study show the interaction of the optimized dipole nano-antenna with a magnetic recording medium when it is illuminated with a focused beam of light
Clinical impact of real-time evaluation of the biological activity and degradation of hepatocyte growth factor
Hepatocyte growth factor (HGF) is essential for injury repair. Despite high HGF levels in chronic ulcers, up-regulation of HGF receptor in ulcer tissue and decreased biological activity of HGF in ulcer secretions have been observed. With a surface plasmon resonance-based method, we assessed the binding of HGF to antibodies, receptors, and the basement membrane and identified binding interactions that are indispensable for the biological activity of HGF. Recombinant HGF (rHGF) lots were tested for activity, structural integrity, and degradation, and the results were verified in an in vitro model of cell injury. Biologically active rHGF, as well as plasma from healthy volunteers, bound to heparan sulphate proteoglycan (HSPG) and to anti-HGF antibodies. Decreased binding to HSPG was the first event in rHGF degradation. This study established the feasibility of identifying patients with chronic inflammation who need exogenous HGF and of using ligand-binding assessment to evaluate rHGF lots for biological activity
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A randomized trial and novel SPR technique identifies altered lipoprotein-LDL receptor binding as a mechanism underlying elevated LDL-cholesterol in APOE4s
At a population level APOE4 carriers (~25% Caucasians) are at higher risk of cardiovascular diseases. The penetrance of genotype is however variable and influenced by dietary fat composition, with the APOE4 allele associated with greater LDL-cholesterol elevation in response to saturated fatty acids (SFA). The etiology of this greater responsiveness is unknown. Here a novel surface plasmon resonance technique (SPR) is developed and used, along with hepatocyte (with the liver being the main organ modulating lipoprotein metabolism and plasma lipid levels) uptake studies to establish the impact of dietary fatty acid composition on, lipoprotein-LDL receptor (LDLR) binding, and hepatocyte uptake, according to APOE genotype status. In men prospectively recruited according to APOE genotype (APOE3/3 common genotype, or APOE3/E4), triglyceride-rich lipoproteins (TRLs) were isolated at fasting and 4-6 h following test meals rich in SFA, unsaturated fat and SFA with fish oil. In APOE4s a greater LDLR binding affinity of postprandial TRL after SFA, and lower LDL binding and hepatocyte internalization, provide mechanisms for the greater LDL-cholesterol raising effect. The SPR technique developed may be used for the future study of the impact of genotype, and physiological and behavioral variables on lipoprotein metabolism
Oynophagia in patients after dental extraction: surface electromyography study
OBJECTIVES: Surface electromyographic (sEMG) studies were performed on 40 adult patients following extraction of lower third and second molars to research the approach and limitations of sEMG evaluation of their odynophagia complaints. METHODS: Parameters evaluated during swallowing and drinking include the timing, number of swallows per 100 cc of water, and range (amplitude) of EMG activity of m. masseter, infrahyoid and submental-submandibular group. The above mentioned variables (mean + standard deviation) were measured for the group of dental patients (n = 40) and control group of healthy adults (n = 40). RESULTS: The duration of swallows and drinking in all tests showed increase in dental patients' group, in which this tendency is statistically significant. There was no statistically significant difference between male and female adults' duration and amplitude of muscle activity during continuous drinking in both groups (p = 0.05). The mean of electric activity (in μV) of m. masseter was significantly lower in the dental patients' group in comparison with control group. The electric activity of submental-submandimular and infrahyoid muscle groups was the same in both groups. CONCLUSION: Surface EMG of swallowing is a simple and reliable noninvasive method for evaluation of odynophagia/dysphagia complaints following dental extraction with low level of discomfort of the examination. The surface EMG studies prove that dysphagia following dental extraction and molar surgery has oral origin, does not affect pharingeal segment and submental-submandibular muscle group. This type of dysphagia has clear EMG signs: increased duration of single swallow, longer drinking time, low range of electric activity of m. masseter, normal range of activity of submental-submandibular muscle group, and the "dry swalow" aftereffect. The data can be used for evaluation of complaints and symptoms, as well as for comparison purposes in pre- and postoperative stages and in EMG monitoring during treatment of post-surgical oral cavity discomfort and dysphagia
General symptom reporting in female fibromyalgia patients and referents: a population-based case-referent study
<p>Abstract</p> <p>Background</p> <p>Fibromyalgia is characterized by widespread musculoskeletal pain and palpation tenderness. In addition to these classic symptoms, fibromyalgia patients tend to report a number of other complaints. What these other complaints are and how often they are reported as compared with related referents from the general population is not very well known. We therefore hypothesized that subjects with fibromyalgia report more of a wide range of symptoms as compared with referents of the same sex and age from the general population.</p> <p>Methods</p> <p>138 women with diagnosed fibromyalgia in primary health care and 401 referents from the general population matched to the cases by sex, age and residential area responded to a postal questionnaire where information on marital status, education, occupational status, income level, immigrant status, smoking habits physical activity, height and weight history and the prevalence of 42 defined symptoms was sought.</p> <p>Results</p> <p>The cases had lower educational and income levels, were more often unemployed, on sick leave or on disability pension and were more often first generation immigrants than the referents. They were also heavier, shorter and more often had a history of excessive food intake and excessive weight loss. When these differences were taken into account, cases reported not only significantly more presumed fibromyalgia symptoms but also significantly more of general symptoms than the referents. The distribution of symptoms was similar in subjects with fibromyalgia and referents, indicating a generally higher symptom reporting level among the former.</p> <p>Conclusion</p> <p>Subjects with fibromyalgia had a high prevalence of reported general symptoms than referents. Some of these differences may be a consequence of the disorder while others may reflect etiological processes.</p
Comparison of the clinical and pathologic staging in patients undergoing radical cystectomy for bladder cancer
Pre-diagnostic circulating insulin-like growth factor-I and bladder cancer risk in the European Prospective Investigation into Cancer and Nutrition
Previous in vitro and case–control studies have found an association between the insulin‐like growth factor (IGF)‐axis and bladder cancer risk. Circulating concentrations of IGF‐I have also been found to be associated with an increased risk of several cancer types; however, the relationship between pre‐diagnostic circulating IGF‐I concentrations and bladder cancer has never been studied prospectively. We investigated the association of pre‐diagnostic plasma concentrations of IGF‐I with risk of overall bladder cancer and urothelial cell carcinoma (UCC) in a case–control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. A total of 843 men and women diagnosed with bladder cancer between 1992 and 2005 were matched with 843 controls by recruitment centre, sex, age at recruitment, date of blood collection, duration of follow‐up, time of day and fasting status at blood collection using an incidence density sampling protocol. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression with adjustment for smoking status. No association was found between pre‐diagnostic circulating IGF‐I concentration and overall bladder cancer risk (adjusted OR for highest versus lowest fourth: 0.91, 95% CI: 0.66–1.24, ptrend = 0.40) or UCC (n of cases = 776; 0.91, 0.65–1.26, ptrend = 0.40). There was no significant evidence of heterogeneity in the association of IGF‐I with bladder cancer risk by tumour aggressiveness, sex, smoking status, or by time between blood collection and diagnosis (pheterogeneity > 0.05 for all). This first prospective study indicates no evidence of an association between plasma IGF‐I concentrations and bladder cancer risk
Do diagnostic delays in cancer matter?
background: The United Kingdom has poorer cancer outcomes than many other countries due partly to delays in diagnosing symptomatic cancer, leading to more advanced stage at diagnosis. Delays can occur at the level of patients, primary care, systems and secondary care. There is considerable potential for interventions to minimise delays and lead to earlier-stage diagnosis.
methods: Scoping review of the published studies, with a focus on methodological issues.
results: Trial data in this area are lacking and observational studies often show no association or negative ones. This review offers methodological explanations for these counter-intuitive findings.
conclusion: While diagnostic delays do matter, their importance is uncertain and must be determined through more sophisticated methods
Menstrual factors, reproductive history, hormone use, and Urothelial carcinoma risk: A prospective study in the EPIC cohort
Background: Urothelial carcinoma (UC) is the predominant (95%) bladder cancer subtype in industrialised nations. Animal and epidemiological human studies suggest that hormonal factors may influence UC risk. Methods: We used an analytic cohort of 333,919 women from the European Prospective Investigation into Cancer and Nutrition Cohort (EPIC). Associations between hormonal factors and incident UC (overall and by tumour grade, by tumour aggressiveness, and by non-muscle invasive UC) risk were evaluated using Cox proportional hazards models. All models were stratified by age at recruitment and study centre, and adjusted for smoking status and intensity, and fruit and vegetable intakes. Results: During a mean of 15 years of follow-up, 529 women developed UC. In a model including number of full-term pregnancies (FTP), menopausal status, and menopausal hormone therapy (MHT) showed an inverse association between, number of FTP was inversely associated with UC risk (HR≥5vs1=0.48, 0.25-0.90; P-trend in parous women=0.010) and MHT-use (compared to non-use) was positively associated with UC risk (HR=1.27, 1.03-1.57), but no dose-response by years of MHT-use was observed. No modification of HRs by smoking status was observed. Finally, sensitivity analysis in never-smokers showed similar HR patterns for number of FTP and no association between MHT-use and UC risk. Association between MHT-use and UC risk only remained significant in current-smokers. No heterogeneity of the risk estimations in the final model was observed by tumour aggressiveness or by tumour grade. A positive association between the MTH-use and non-muscle invasive UC risk was observed. Conclusion: Increasing number of FTP may reduce UC risk. Our results provided limited evidence for a role of MHT-use in UC risk due to residual confounding by tobacco. Impact: More detailed studies on parity are needed to understand the possible effects of perinatal hormone changes in urothelial cells
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