904 resultados para Study approaches and experimental validation
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Circulating Fibrocytes (CFs) are bone marrow-derived mesenchymal progenitor cells that express a similar pattern of surface markers related to leukocytes, hematopoietic progenitor cells and fibroblasts. CFs precursor display an ability to differentiate into fibroblasts and Myofibroblasts, as well as adipocytes. Fibrocytes have been shown to contribute to tissue fibrosis in the end-stage renal disease (ESRD), as well as in other fibrotic diseases, leading to fibrogenic process in other organs including lung, cardiac, gut and liver. This evidence has been confirmed by several experimental proofs in mice models of kidney injury. In the present study, we developed a protocol for the study of CFs, by using peripheral blood monocytes cells (PBMCs) samples collected from healthy human volunteers. Thanks to a flow cytometry method, in vitro culture assays and the gene expression assays, we are able to study and characterize this CFs population. Moreover, results confirmed that these approaches are reliable and reproducible for the investigation of the circulating fibrocytes population in whole blood samples. Our final aim is to confirm the presence of a correlation between the renal fibrosis progression, and the different circulating fibrocyte levels in Chronic Kidney Disease (CKD) patients. Thanks to a protocol study presented and accepted by the Ethic Committee we are continuing the study of CFs induction in a cohort of sixty patients affected by CKD, divided in three distinct groups for different glomerular filtration rate (GFR) levels, plus a control group of thirty healthy subjects. Ongoing experiments will determine whether circulating fibrocytes represent novel biomarkers for the study of CKD progression, in the early and late phases of this disease.
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The present thesis focuses on elastic waves behaviour in ordinary structures as well as in acousto-elastic metamaterials via numerical and experimental applications. After a brief introduction on the behaviour of elastic guided waves in the framework of non-destructive evaluation (NDE) and structural health monitoring (SHM) and on the study of elastic waves propagation in acousto-elastic metamaterials, dispersion curves for thin-walled beams and arbitrary cross-section waveguides are extracted via Semi-Analytical Finite Element (SAFE) methods. Thus, a novel strategy tackling signal dispersion to locate defects in irregular waveguides is proposed and numerically validated. Finally, a time-reversal and laser-vibrometry based procedure for impact location is numerically and experimentally tested. In the second part, an introduction and a brief review of the basic definitions necessary to describe acousto-elastic metamaterials is provided. A numerical approach to extract dispersion properties in such structures is highlighted. Afterwards, solid-solid and solid-fluid phononic systems are discussed via numerical applications. In particular, band structures and transmission power spectra are predicted for 1P-2D, 2P-2D and 2P-3D phononic systems. In addition, attenuation bands in the ultrasonic as well as in the sonic frequency regimes are experimentally investigated. In the experimental validation, PZTs in a pitch-catch configuration and laser vibrometric measurements are performed on a PVC phononic plate in the ultrasonic frequency range and sound insulation index is computed for a 2P-3D phononic barrier in the sonic frequency range. In both cases the numerical-experimental results comparison confirms the existence of the numerical predicted band-gaps. Finally, the feasibility of an innovative passive isolation strategy based on giant elastic metamaterials is numerically proved to be practical for civil structures. In particular, attenuation of seismic waves is demonstrated via finite elements analyses. Further, a parametric study shows that depending on the soil properties, such an earthquake-proof barrier could lead to significant reduction of the superstructure displacement.
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In this thesis we studied the stereodynamic behavior of 1,2-azaborines variously substituted on boron (7a, 7b, 13). Depending on the hindrance of the asymmetric aryl substituent the resulting conformations could be stereolabile or configurationally stable. Through dynamic NMR and lineshape simulation, the energy rotational barriers of the different conformers are obtained. When the barrier is higher than 22-23 kcal/mol stable atropisomers that are fisically separable could be obtained (case of compound 13) and the free activation energy barrier is determinable by kinetic analysis. Absolute configuration of two atropisomers were assigned by comparison between computational calculations and experimental ECD. Isosteric compound 21 is then synthesized in order to compare the rotational barrier around B-Caryl with the one around Cnaphth-Caryl bond.
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OBJECTIVES: The present literature review conceptualises landscape as a health resource that promotes physical, mental, and social well-being. Different health-promoting landscape characteristics are discussed. METHODS: This article is based on a scoping study which represents a special kind of qualitative literature review. Over 120 studies have been reviewed in a five-step-procedure, resulting in a heuristic device. RESULTS: A set of meaningful pathways that link landscape and health have been identified. Landscapes have the potential to promote mental well-being through attention restoration, stress reduction, and the evocation of positive emotions; physical well-being through the promotion of physical activity in daily life as well as leisure time and through walkable environments; and social well-being through social integration, social engagement and participation, and through social support and security. CONCLUSION: This scoping study allows us to systematically describe the potential of landscape as a resource for physical, mental and social well-being. A heuristic framework is presented that can be applied in future studies, facilitating systematic and focused research approaches and informing practical public health interventions.
An examination chair to measure internal rotation of the hip in routine settings: a validation study
Resumo:
OBJECTIVE: To determine the performance of a newly developed examination chair as compared with the clinical standard of assessing internal rotation (IR) of the flexed hip with a goniometer.
METHODS: The examination chair allowed measurement of IR in a sitting position simultaneously in both hips, with hips and knees flexed 90 degrees, lower legs hanging unsupported and a standardized load of 5 kg applied to both ankles using a bilateral pulley system. Clinical assessment of IR was performed in supine position with hips and knees flexed 90 degrees using a goniometer. Within the framework of a population-based inception cohort study, we calculated inter-observer agreement in two samples of 84 and 64 consecutive, unselected young asymptomatic males using intra-class correlation coefficients (ICC) and determined the correlation between IR assessed with examination chair and clinical assessment.
RESULTS: Inter-observer agreement was excellent for the examination chair (ICC right hip, 0.92, 95% confidence interval [CI] 0.89-0.95; ICC left hip, 0.90, 95% CI 0.86-0.94), and considerably higher than that seen with clinical assessment (ICC right hip, 0.65, 95% CI 0.49-0.77; ICC left hip, 0.69, 95% CI 0.54-0.80, P for difference in ICC between examination chair and clinical assessment
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Background: Annual syphilis testing was reintroduced in the Swiss HIV Cohort Study (SHCS) in 2004. We prospectively studied occurrence, risk factors, clinical manifestations, diagnostic approaches and treatment of syphilis. Methods: Over a period of 33 months, participants with positive test results for Treponema pallidum hemagglutination assay were studied using the SHCS database and an additional structured case report form. Results: Of 7244 cohort participants, 909 (12.5%) had positive syphilis serology. Among these, 633 had previously been treated and had no current signs or symptoms of syphilis at time of testing. Of 218 patients with newly detected untreated syphilis, 20% reported genitooral contacts as only risk behavior and 60% were asymptomatic. Newly detected syphilis was more frequent among men who have sex with men (MSM) [adjusted odds ratio (OR) 2.8, P < 0.001], in persons reporting casual sexual partners (adjusted OR 2.8, P < 0.001) and in MSM of younger age (P = 0.05). Only 35% of recommended cerebrospinal fluid (CFS) examinations were performed. Neurosyphilis was diagnosed in four neurologically asymptomatic patients; all of them had a Venereal Disease Research Laboratory (VDRL) titer of 1:≥32. Ninety-one percent of the patients responded to treatment with at least a four-fold decline in VDRL titer. Conclusion: Syphilis remains an important coinfection in the SHCS justifying reintroduction of routine screening. Genitooral contact is a significant way of transmission and young MSM are at high risk for syphilis. Current guidelines to rule out neurosyphilis by CSF analysis are inconsistently followed in clinical practice. Serologic treatment response is above 90% in the era of combination antiretroviral therapy.
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The widespread use of artificial nestboxes has led to significant advances in our knowledge of the ecology, behaviour and physiology of cavity nesting birds, especially small passerines Nestboxes have made it easier to perform routine monitoring and experimental manipulation of eggs or nestlings, and also repeatedly to capture, identify and manipulate the parents However, when comparing results across study sites the use of nestboxes may also Introduce a potentially significant confounding variable in the form of differences in nestbox design amongst studies, such as their physical dimensions, placement height, and the way in which they are constructed and maintained However, the use of nestboxes may also introduce an unconsidered and potentially significant confounding variable clue to differences in nestbox design amongst studies, such as their physical dimensions, placement height, and the way in which they are constructed and maintained Here we review to what extent the characteristics of artificial nestboxes (e g size, shape, construction material, colour) are documented in the 'methods' sections of publications involving hole-nesting passerine birds using natural or excavated cavities or artificial nestboxes for reproduction and roosting Despite explicit previous recommendations that authors describe in detail the characteristics of the nestboxes used, we found that the description of nestbox characteristics in most recent publications remains poor and insufficient We therefore list the types of descriptive data that should be included in the methods sections of relevant manuscripts and justify this by discussing how variation in nestbox characteristics can affect or confound conclusions from nestbox studies We also propose several recommendations to improve the reliability and usefulness of research based on long-term studies of any secondary hole-nesting species using artificial nestboxes for breeding or roosting.
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Apolipoprotein J (ApoJ) is a component of plasma high-density lipoproteins. Previous studies have shown progressive recovery of ApoJ sialic acid content with increased duration of alcohol abstinence. Therefore, the sialic acid index of plasma apolipoprotein J (SIJ) seems to be a promising alcohol biomarker. Phosphatidylethanol (PEth) is a direct ethanol metabolite and has recently attracted attention as a biomarker of prolonged intake of higher amounts of alcohol. The aim of the pilot study was to explore sensitivity, specificity, and normalization of SIJ and PEth in comparison with traditional and emerging biomarkers.
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Strokes due to transmural vasculitis associated with coccidioidal meningitis result in significant morbidity and mortality. The immunological and inflammatory processes responsible are poorly understood. To determine the inflammatory mediators, i.e. cytokines, chemokines, iNOS, matrix metalloproteinase-9 (MMP-9), that possibly contribute to vasculitis, temporal mRNA expression in brain basilar artery samples and MMP-9 protein in the CSF of male NZW rabbits infected intracisternally with 6.5 x 10(4) arthroconidia of Coccidioides immitis were assessed. Five infected and 3 sham-injected rabbits at each time point were euthanized 4, 9, 14 and 20 days post infection. All infected rabbits had neurological abnormalities and severe vasculitis in the basilar arteries on days 9-20. In basilar arteries of infected animals versus controls, mRNAs encoding for IL-6, iNOS, IFN-gamma, IL-2, MCP-1, IL-1beta, IL-10, TNF-alpha, CCR-1, MMP-9, TGF-beta, as well as MMP-9 protein in CSF, were found to be significantly up-regulated. Thus, this study identified inflammatory mediators associated with CNS vasculitis and meningitis due to C. immitis infection. Assessment of the individual contribution of each mediator to vasculitis may offer novel approaches to the treatment of coccidioidal CNS infection. This study also provides unique methodology for immunology studies in a rabbit model.
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This article reports about the internet based, second multicenter study (MCS II) of the spine study group (AG WS) of the German trauma association (DGU). It represents a continuation of the first study conducted between the years 1994 and 1996 (MCS I). For the purpose of one common, centralised data capture methodology, a newly developed internet-based data collection system ( http://www.memdoc.org ) of the Institute for Evaluative Research in Orthopaedic Surgery of the University of Bern was used. The aim of this first publication on the MCS II was to describe in detail the new method of data collection and the structure of the developed data base system, via internet. The goal of the study was the assessment of the current state of treatment for fresh traumatic injuries of the thoracolumbar spine in the German speaking part of Europe. For that reason, we intended to collect large number of cases and representative, valid information about the radiographic, clinical and subjective treatment outcomes. Thanks to the new study design of MCS II, not only the common surgical treatment concepts, but also the new and constantly broadening spectrum of spine surgery, i.e. vertebro-/kyphoplasty, computer assisted surgery and navigation, minimal-invasive, and endoscopic techniques, documented and evaluated. We present a first statistical overview and preliminary analysis of 18 centers from Germany and Austria that participated in MCS II. A real time data capture at source was made possible by the constant availability of the data collection system via internet access. Following the principle of an application service provider, software, questionnaires and validation routines are located on a central server, which is accessed from the periphery (hospitals) by means of standard Internet browsers. By that, costly and time consuming software installation and maintenance of local data repositories are avoided and, more importantly, cumbersome migration of data into one integrated database becomes obsolete. Finally, this set-up also replaces traditional systems wherein paper questionnaires were mailed to the central study office and entered by hand whereby incomplete or incorrect forms always represent a resource consuming problem and source of error. With the new study concept and the expanded inclusion criteria of MCS II 1, 251 case histories with admission and surgical data were collected. This remarkable number of interventions documented during 24 months represents an increase of 183% compared to the previously conducted MCS I. The concept and technical feasibility of the MEMdoc data collection system was proven, as the participants of the MCS II succeeded in collecting data ever published on the largest series of patients with spinal injuries treated within a 2 year period.
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OBJECTIVES: There is concern regarding the possible health effects of cellular telephone use. We examined whether the source of funding of studies of the effects of low-level radiofrequency radiation is associated with the results of studies. We conducted a systematic review of studies of controlled exposure to radiofrequency radiation with health-related outcomes (electroencephalogram, cognitive or cardiovascular function, hormone levels, symptoms, and subjective well-being). DATA SOURCES: We searched EMBASE, Medline, and a specialist database in February 2005 and scrutinized reference lists from relevant publications. DATA EXTRACTION: Data on the source of funding, study design, methodologic quality, and other study characteristics were extracted. The primary outcome was the reporting of at least one statistically significant association between the exposure and a health-related outcome. Data were analyzed using logistic regression models. DATA SYNTHESIS: Of 59 studies, 12 (20%) were funded exclusively by the telecommunications industry, 11 (19%) were funded by public agencies or charities, 14 (24%) had mixed funding (including industry), and in 22 (37%) the source of funding was not reported. Studies funded exclusively by industry reported the largest number of outcomes, but were least likely to report a statistically significant result: The odds ratio was 0.11 (95% confidence interval, 0.02-0.78), compared with studies funded by public agencies or charities. This finding was not materially altered in analyses adjusted for the number of outcomes reported, study quality, and other factors. CONCLUSIONS: The interpretation of results from studies of health effects of radiofrequency radiation should take sponsorship into account.
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Fluconazole is effective in the therapy of cryptococcal meningitis in patients with AIDS. The optimal dosage of fluconazole and the impact of combination with flucytosine are not known. In this study, rabbits with experimental cryptococcal meningitis were given fluconazole at low, intermediate, or high dose or in combination with a low or intermediate dose of flucytosine. Serial cerebrospinal fluid (CSF) examinations showed that all three doses of fluconazole and low-dose fluconazole in combination with intermediate-dose flucytosine were effective in reducing CSF cryptococcal titer, lactate, white blood cell count, and cryptococcal antigen (CRAG) titers. The intermediate and high doses of fluconazole reduced CSF fungal (P < .05) and CRAG (P < .001) titers earlier than low-dose fluconazole alone or in combination with flucytosine. Only the highest dose of fluconazole reduced brain edema after 7 days. In this model of cryptococcal meningitis, there was evidence of a dose response with fluconazole but no in vivo synergism with flucytosine.
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PURPOSE: To prospectively quantify in vitro the influence of gadopentetate dimeglumine and ioversol on the magnetic resonance (MR) imaging signal observed with a variety of musculoskeletal pulse sequences to predict optimum gadolinium concentrations for direct MR arthrography at 1.5 and 3.0 T. MATERIALS AND METHODS: In an in vitro study, T1 and T2 relaxation times of three dilution series of gadopentetate dimeglumine (concentration, 0-20.0 mmol gadolinium per liter) at ioversol concentrations with iodine concentration of 0, 236.4, and 1182 mmol iodine per liter (corresponding to 0, 30, and 150 mg of iodine per milliliter) were measured at 1.5 and 3.0 T. The relaxation rate dependence on concentrations of gadolinium and iodine was analytically modeled, and continuous profiles of signal versus gadolinium concentration were calculated for 10 pulse sequences used in current musculoskeletal imaging. After fitting to experimental discrete profiles, maximum signal-to-noise ratio (SNR), gadolinium concentration with maximum SNR, and range of gadolinium concentration with 90% of maximum SNR were derived. The overall influence of field strength and iodine concentration on these parameters was assessed by using t tests. The deviation of simulated from experimental signal-response profiles was assessed with the autocorrelation of the residuals. RESULTS: The model reproduced relaxation rates of 0.37-38.24 sec(-1), with a mean error of 4.5%. Calculated SNR profiles matched the discrete experimental profiles, with autocorrelation of the residuals divided by the mean of less than 5.0. Admixture of ioversol consistently reduced T1 and T2, narrowed optimum gadolinium concentration ranges (P = .004-.006), and reduced maximum SNR (P < .001 to not significant). Optimum gadolinium concentration was 0.7-3.4 mmol/L at both field strengths. At 3.0 T, maximum SNR was up to 75% higher than at 1.5 T. CONCLUSION: Admixture of ioversol to gadopentetate dimeglumine solutions results in a consistent additional relaxation enhancement, which can be analytically modeled to allow a near-quantitative a priori optimized match of contrast media concentrations and imaging protocol for a broad variety of pulse sequences.