Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 272
Filtrar
1.
Phys Rev E ; 109(1-1): 014222, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38366503

RESUMO

We study the ensemble of pseudo-spin 1/2 ultracold bosons, performing Lévy flights, confined in a parabolic potential. The (pseudo-) spin-orbit coupling (SOC) is additionally imposed on these particles. We consider the structure and dynamics of macroscopic pseudospin qubits based on Bose-Einstein condensates, obtained from the above "fractional" bosons. Under "fractional" we understand the substitution of the ordinary second derivative (kinetic energy term) in the Gross-Pitaevskii equation by a so-called fractional Laplacian, characterized by the Lévy index µ. We show that the joint action of interparticle interaction, SOC, and Zeeman splitting in a synthetic magnetic field makes the dynamics of corresponding qubit highly nontrivial with evident chaotic features at both strong interactions and Lévy indices µâ†’1 when the Lévy trajectories of bosons with long jumps dominated over those derived from ordinary Gaussian distribution, corresponding to µ=2. Using analytical and numerical arguments, we discuss the possibilities to control the above qubit using the synergy of SOC, interaction strength, and "fractionality," characterized by the Lévy index µ.

2.
Clin Radiol ; 73(8): 757.e9-757.e19, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29779758

RESUMO

AIM: To test the potential of unenhanced cardiac- and respiratory-motion-corrected three-dimensional steady-state free precession (3D-SSFP) magnetic resonance imaging (MRI) for the assessment of inferior vena cava (IVC) thrombus in patients with clear-cell renal cell carcinoma (cRCC), compared to standard contrast-enhanced (CE)-MRI and CE-computed tomography (CT). MATERIALS AND METHODS: Eighteen patients with cRCC and IVC thrombus, who received CE-MRI and 3D-SSFP at 1.5 T between June 2015 and December 2017, were included. The diagnostic performance of 3D-SSFP in determining the level of thrombus extension, contrast-to-noise ratio (CNR), and image quality were compared with standard MRI/CT and validated against intraoperative and histopathology results. RESULTS: There was 100% agreement between 3D-SSFP, 83.3% agreement between CE-MRI, and 71.4% agreement between CE-CT and surgical findings regarding the level of IVC thrombus. In addition, 3D-SSFP showed a slightly superior estimate of pathological IVC volume. 3D-SSFP reached a significantly higher CNR in the supra- and infrarenal IVC compared to the morphological sequence T2-weighted half-Fourier axial single-shot fast spin-echo (T2-HASTE) and all phases of CE-MRI. More specifically, 3D-SSFP showed a significantly higher CNR in the infrarenal IVC (mean CNR of 10.09±5.74 versus 4.21±2.33 in the delayed phase, p≤0.001) and in the suprarenal IVC (mean CNR of 9.22±4.11 versus 4.84±5.74 in the late arterial phase, p=0.015). CE-CT also was significantly inferior to 3D-SSFP (p≤0.01) and slightly inferior to CE-MRI (p>0.05). The thrombus delineation score for 3D-SSFP (4.38±0.67) was higher compared to CE-MRI (3.76±0.56, p=0.005). CONCLUSION: This preliminary study indicates that 3D-SSFP can achieve an accurate assessment of IVC thrombus in cRCC patients without the need for contrast medium administration, being superior to standard MRI and CT.


Assuntos
Carcinoma de Células Renais/complicações , Imageamento Tridimensional/métodos , Neoplasias Renais/complicações , Neoplasias Renais/patologia , Imageamento por Ressonância Magnética/métodos , Veia Cava Inferior , Trombose Venosa/diagnóstico por imagem , Trombose Venosa/etiologia , Adulto , Idoso , Carcinoma de Células Renais/patologia , Carcinoma de Células Renais/cirurgia , Meios de Contraste , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Neoplasias Renais/cirurgia , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Nefrectomia , Estudos Retrospectivos , Trombectomia , Tomografia Computadorizada por Raios X , Trombose Venosa/cirurgia
3.
J Chem Phys ; 142(21): 212446, 2015 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-26049466

RESUMO

Photosynthetic antenna complexes harvest sunlight and efficiently transport energy to the reaction center where charge separation powers biochemical energy storage. The discovery of existence of long lived quantum coherence during energy transfer has sparked the discussion on the role of quantum coherence on the energy transfer efficiency. Early works assigned observed coherences to electronic states, and theoretical studies showed that electronic coherences could affect energy transfer efficiency--by either enhancing or suppressing transfer. However, the nature of coherences has been fiercely debated as coherences only report the energy gap between the states that generate coherence signals. Recent works have suggested that either the coherences observed in photosynthetic antenna complexes arise from vibrational wave packets on the ground state or, alternatively, coherences arise from mixed electronic and vibrational states. Understanding origin of coherences is important for designing molecules for efficient light harvesting. Here, we give a direct experimental observation from a mutant of LH2, which does not have B800 chromophores, to distinguish between electronic, vibrational, and vibronic coherence. We also present a minimal theoretical model to characterize the coherences both in the two limiting cases of purely vibrational and purely electronic coherence as well as in the intermediate, vibronic regime.


Assuntos
Complexos de Proteínas Captadores de Luz/química , Complexos de Proteínas Captadores de Luz/metabolismo , Fotossíntese , Rhodobacter sphaeroides/química , Vibração , Transferência de Energia , Teoria Quântica , Rhodobacter sphaeroides/metabolismo
4.
J Chem Phys ; 139(8): 084201, 2013 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-24006987

RESUMO

Assigning absolute phase to two-dimensional (2D) third-order nonlinear optical signals generally requires acquiring both the rephasing and the non-rephasing signals and comparing the sum of the two to spectrally resolved pump-probe spectra. To date, however, Gradient Assisted Photon Echo Spectroscopy (GRAPES) has only been able to acquire rephasing spectra. Such a constraint requires a new phasing protocol. Here, we analytically prove that the rephasing and non-rephasing spectra can be phased independently using pump-probe signal. We verify this result holds even for finite duration pulses by simulation. This relationship holds for all 2D spectroscopies, not only GRAPES. In addition, we present improvements to GRAPES that enable acquisition of rephasing and non-rephasing signals in different phase-matched directions. We employ our phasing protocol to phase the data for laser dye IR-144, leading to reconstruction of purely absorptive 2D spectrum.


Assuntos
Análise Espectral
5.
Br J Anaesth ; 110(1): 87-95, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23048069

RESUMO

BACKGROUND: An organizational approach is proposed as an immediate solution for improving postoperative pain (POP) management. The aim was to evaluate the clinical effectiveness of a quality management system (QMS), based on procedure-specific, multimodal analgesic protocols, modified to meet the individual patients' requirements. METHODS: Patients from the orthopaedic, gynaecological, visceral, and trauma surgery departments of the university hospital were involved in two prospective surveys. Survey 1 was performed at baseline and survey 2 was performed after the implementation of QMS within an interval of 1 year. The patients were asked to report pain intensity on the visual rating scale, incidence of analgesia-related side-effects, and incidence of pain interference with the items of life quality and their satisfaction with the treatment of POP. RESULTS: Patients from Survey 2 (n=251) reported 25-30% less pain than those from Survey 1 (n=269) (P<0.0001). Nausea was reported by 40% of the patients from Survey 1 vs 17% from Survey 2, vomiting by 25 vs 11% and fatigue by 76% in Survey 1 vs 30% in Survey 2 (P<0.0001). Life quality and patients' satisfaction improved in Survey 2 vs Survey 1 (P<0.001). CONCLUSIONS: The implementation of QMS allowed the reduction in POP intensity with a simultaneous decrease in analgesia-related side-effects. This has led to an increased quality of life and patient satisfaction.


Assuntos
Dor Pós-Operatória/tratamento farmacológico , Melhoria de Qualidade/organização & administração , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Analgésicos não Narcóticos/efeitos adversos , Analgésicos não Narcóticos/uso terapêutico , Analgésicos Opioides/efeitos adversos , Analgésicos Opioides/uso terapêutico , Terapia Combinada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Clínicas de Dor , Medição da Dor , Equipe de Assistência ao Paciente/organização & administração , Satisfação do Paciente , Estudos Prospectivos , Garantia da Qualidade dos Cuidados de Saúde , Qualidade de Vida , Inquéritos e Questionários , Adulto Jovem
7.
Med Hypotheses ; 79(3): 365-7, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22738906

RESUMO

Biomedical research in the 21st century increasingly relies on pathogen-free nonhuman primates (NHPs) to model human pathophysiology. Despite adherence to protocols designed to maintain pathogen-free colonies, reports of tuberculosis regularly appear. We hypothesize that, undetected by standard screening protocols, mycobacteria of the Mycobacterium tuberculosis complex (MTBC) continue to circulate in established NHP colonies and may, in addition, be periodically reintroduced with newly imported animals. The tuberculin skin test (TST), the accepted standard screening test for tuberculosis, relies on the host's immune response to detect infection, but empirical data suggest that TST lacks both specificity and, particularly in certain NHP species and in immune compromised animals, sensitivity. In order to improve the detection of MTBC infection in NHP colonies we propose new screening protocols that incorporate molecular methods to detect mycobacteria. These new tests do not rely on the host's immune response and may allow for strain typing of the pathogens - enhancing our ability to elucidate patterns of disease transmission. Moreover, the ability to rapidly and noninvasively collect specimens could lead to an improved appreciation of the burden of MTBC circulating in populations of NHPs and humans, including drug-resistant strains, data that are invaluable to public health efforts.


Assuntos
Tuberculose/fisiopatologia , Animais , Modelos Teóricos , Primatas , Testes Cutâneos , Tuberculose/diagnóstico , Tuberculose/imunologia
8.
Toxicol In Vitro ; 26(3): 485-92, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22230562

RESUMO

Methylmercury (MeHg) is a ubiquitous toxicant that targets the developing fetal nervous system. MeHg interacts with the Notch signaling pathway, a highly-conserved intercellular signaling mechanism required for normal development. Notch signaling is conveyed by activation of the genes in the enhancer of split (E(spl)) locus in Drosophila. We have previously shown that acute high doses of MeHg upregulate several E(spl) genes in Drosophila neural-derived C6 cells. Furthermore, MeHg induction of E(spl) can occur independent of the Notch receptor itself. We now show that MeHg, unlike inorganic mercury (HgCl2), preferentially upregulates E(spl)mδ and E(spl)mγ in Drosophila C6 cells. This is distinct from Delta ligand-induced Notch signaling in which no induction of E(spl)mδ is seen. MeHg is also seen to specifically upregulate E(spl)mδ in Drosophila embryos where HgCl2 showed no such effect. Additionally, treatment of embryos with MeHg caused a consistent failure in axonal outgrowth of the intersegmental nerve (ISN). This ISN phenotype was partially replicated by genetic activation of the Notch pathway, but was not replicated by increasing expression of E(spl)mδ. These data suggest a role for Notch signaling and the E(spl)mδ target gene in MeHg toxicity, however, the site of action for E(spl)mδ in this system remains to be elucidated.


Assuntos
Compostos de Metilmercúrio/toxicidade , Receptores Notch/metabolismo , Transdução de Sinais/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Linhagem Celular , Proteínas de Drosophila/genética , Drosophila melanogaster , Embrião não Mamífero , Desenvolvimento Embrionário/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Proteínas Repressoras/genética
9.
Am J Primatol ; 74(6): 543-50, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21932331

RESUMO

Humans and nonhuman primates (NHP) interact in a variety of contexts. The frequency, duration, and intensity of interspecies interaction influence the likelihood that contact results in cross-species transmission of infectious agents. In this study, we present results of a cross-sectional survey of attendees at a national conference of primatologists, characterizing their occupational exposures to NHP. Of 116 individuals who participated in the study, 68.1% reported having worked with NHP in a field setting, 68.1% in a laboratory setting, and 24.1% at a zoo or animal sanctuary. Most subjects (N=98, 84.5%) reported having worked with multiple NHP taxa, including 46 (39.7%) who had worked with more than five distinct taxa. Sixty-nine subjects (59.5%) recalled having been scratched by a NHP and 48 (41.1%) had been bitten; 32 subjects reporting being bitten more than once. Eleven subjects (9.5%) reported having been injured by a needle containing NHP tissue or body fluids. We conclude that primatologists are at high risk for exposure to NHP-borne infectious agents. Furthermore, primatologists' varied occupational activities often bring them into contact with multiple NHP species in diverse contexts and geographic areas, over extended periods of time, making them a unique population with respect to zoonotic and anthropozoonotic disease risk.


Assuntos
Exposição Ocupacional , Doenças dos Primatas/transmissão , Zoonoses/epidemiologia , Animais , Mordeduras e Picadas , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/transmissão , Estudos Transversais , Demografia , Humanos , Primatas , Fatores de Risco , Assunção de Riscos , Meio Social , Inquéritos e Questionários
10.
Rev Sci Instrum ; 80(4): 044102, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19405676

RESUMO

We describe here the Harvard integrated cavity output spectroscopy (ICOS) isotope instrument, a mid-IR infrared spectrometer using ICOS to make in situ measurements of the primary isotopologues of water vapor (H(2)O, HDO, and H(2) (18)O) in the upper troposphere and lower stratosphere (UTLS). The long path length provided by ICOS provides the sensitivity and accuracy necessary to measure these or other trace atmospheric species at concentrations in the ppbv range. The Harvard ICOS isotope instrument has been integrated onto NASA's WB-57 high-altitude research aircraft and to date has flown successfully in four field campaigns from winter 2004-2005 to the present. Off-axis alignment and a fully passive cavity ensure maximum robustness against the vibrationally hostile aircraft environment. The very simple instrument design permitted by off-axis ICOS is also helpful in minimizing contamination necessary for accurate measurements in the dry UTLS region. The instrument is calibrated in the laboratory via two separate water addition systems and crosscalibrated against other instruments. Calibrations have established an accuracy of 5% for all species. The instrument has demonstrated measurement precision of 0.14 ppmv, 0.10 ppbv, and 0.16 ppbv in 4 s averages for H(2)O, HDO, and H(2) (18)O, respectively. At a water vapor mixing ratio of 5 ppmv the isotopologue ratio precision is 50[per thousand] and 30[per thousand] for deltaD and delta(18)O, respectively.

11.
Appl Opt ; 48(8): 1514-9, 2009 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-19277084

RESUMO

Wavelength selective coatings are of common use in order to enhance the efficiency of devices heated by radiation such as solar thermal collectors. The use of suitable materials and the optimization of coating layer thicknesses are advisable ways to maximize the absorption. Further improvement is achievable by embedding particles in certain layers in order to modify material properties. We focus on optimizing the absorption behavior of a solar collector setup using copper as substrate, a layer of amorphous hydrogenated carbon with embedded titanium carbide particles (a-C:H/TiC), and an antireflection coating of amorphous silicon dioxide (aSiO(2)). For the setup utilizing homogeneous particle distribution, a relative absorption of 90.98% was found, while inhomogeneous particle embedding yielded 98.29%. These results are particularly interesting since until now, absorption of more than 95% was found only by using embedded Cr but not by using the more biocompatible Ti.

12.
Nature ; 457(7228): 451-4, 2009 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-19158792

RESUMO

Massive galaxies in the young Universe, ten billion years ago, formed stars at surprising intensities. Although this is commonly attributed to violent mergers, the properties of many of these galaxies are incompatible with such events, showing gas-rich, clumpy, extended rotating disks not dominated by spheroids. Cosmological simulations and clustering theory are used to explore how these galaxies acquired their gas. Here we report that they are 'stream-fed galaxies', formed from steady, narrow, cold gas streams that penetrate the shock-heated media of massive dark matter haloes. A comparison with the observed abundance of star-forming galaxies implies that most of the input gas must rapidly convert to stars. One-third of the stream mass is in gas clumps leading to mergers of mass ratio greater than 1:10, and the rest is in smoother flows. With a merger duty cycle of 0.1, three-quarters of the galaxies forming stars at a given rate are fed by smooth streams. The rarer, submillimetre galaxies that form stars even more intensely are largely merger-induced starbursts. Unlike destructive mergers, the streams are likely to keep the rotating disk configuration intact, although turbulent and broken into giant star-forming clumps that merge into a central spheroid. This stream-driven scenario for the formation of discs and spheroids is an alternative to the merger picture.

13.
Chembiochem ; 9(4): 573-84, 2008 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-18293298

RESUMO

Biologically formed silica is produced at ambient conditions under the control of molecular and physicochemical processes that are apparently integrated in biosilica morphogenesis, but the mechanisms are not yet fully understood. With the recent identification of small polypeptides and proteins that are encapsulated inside the biosilica and functional in silica polymerization in vitro, it is of importance to determine whether interactions between inorganic silica species and these organic compounds occur in vivo. A time-resolved analysis of valve formation in synchronously growing cells of the diatom species Navicula pelliculosa enabled us to characterize the relevant chemical bonds by attenuated total reflectance Fourier-transformed infrared (ATR-FTIR) spectroscopy. Typically, inorganic bonds of Si-O-Si (bands at 1058, 843 cm(-1)), Si-OH (3689 cm(-1)), and P=O (1239 cm(-1)) and organic bonds of proteinaceous matter (with the amide I and II bands at 1642 and 1543 cm(-1), respectively) were positively identified during one cycle of valve formation. The observed variations in FTIR band intensity and location represented specific interactions between organic and inorganic molecules during the major silicification event, during which stretching of the Si-O bonds was predominantly noticed. The experimentally obtained frequencies (nu) of the major bonds corresponded to those that were obtained by MM+ and PM3 FTIR simulations for organo-silica interactions based on biomolecules that are proposed to be involved in biosilica formation. The results indicated that hydrogen bonds originated from interactions, albeit weak, between organic phosphate or amine groups to the inorganic hydroxyl groups or oxygen atoms from the silicic acid and/or silica. The existence of covalent P-O-Si bonds and electrostatic interactions could not be excluded. These interactions clearly suggest that biomolecules actively contribute to the silica polymerization process during valve formation in N. pelliculosa, and also might act comparably in other diatoms species in which similar biomolecules have been identified.


Assuntos
Diatomáceas/química , Diatomáceas/citologia , Compostos Orgânicos/análise , Compostos Orgânicos/química , Dióxido de Silício/análise , Dióxido de Silício/química , Simulação por Computador , Modelos Moleculares , Estrutura Molecular , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Proc Natl Acad Sci U S A ; 104(25): 10441-6, 2007 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-17563373

RESUMO

The role of external ionic strength in diatom biosilica formation was assessed by monitoring the nanostructural changes in the biosilica of the two marine diatom species Thalassiosira punctigera and Thalassiosira weissflogii that was obtained from cultures grown at two distinct salinities. Using physicochemical methods, we found that at lower salinity the specific surface area, the fractal dimensions, and the size of mesopores present in the biosilica decreased. Diatom biosilica appears to be denser at the lower salinity that was applied. This phenomenon can be explained by assuming aggregation of smaller coalescing silica particles inside the silica deposition vesicle, which would be in line with principles in silica chemistry. Apparently, external ionic strength has an important effect on diatom biosilica formation, making it tempting to propose that uptake of silicic acid and other external ions may take place simultaneously. Uptake and transport of reactants in the proximity of the expanding silica deposition vesicle, by (macro)pinocytosis, are more likely than intracellular stabilization and transport of silica precursors at the high concentrations that are necessary for the formation of the siliceous frustule components.


Assuntos
Diatomáceas/fisiologia , Nanoestruturas/química , Dióxido de Silício/metabolismo , Cloreto de Sódio/metabolismo , Fenômenos Químicos , Físico-Química , Diatomáceas/química , Diatomáceas/crescimento & desenvolvimento , Modelos Biológicos , Nanoestruturas/ultraestrutura , Concentração Osmolar , Dióxido de Silício/química
15.
Exp Clin Endocrinol Diabetes ; 114(9): 498-505, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17115347

RESUMO

UNLABELLED: Patient registries are valuable tools to study long-term morbidity and mortality of rare diseases. Acromegaly is rare (incidence 3-4/mill/year, prevalence 40-70/mill; approx. 300 new patients/yr and up to 5700 patients in Germany). Diagnostic and therapeutic possibilities have considerably improved, but treatment results remain often unsatisfactory. The main cause is residual disease activity after surgery, most importantly due to invasive macroadenomas. The German Acromegaly Registry is an initiative of the Pituitary Study Group of the German Endocrine Society (DGE). Formally established in January 2003 by the Board of the DGE, long-term financial support is guaranteed by an unrestricted grant from Novartis Pharma GmbH to the DGE. The registry cooperates closely with the United Kingdom and the Austrian registries. The aim of the German Acromegaly Registry is to establish a database of sufficient epidemiological strength in order to (1) document co-morbidity and mortality, (2) provide data on diagnostic and therapeutic procedures/effectiveness, (3) enable comparison of procedures in different national centres, (4) provide information for patient support groups/interaction with health care providers, (5) enable comparison with other national registries within Europe. The registry has at present 82 participating centres, and 42 have included patients (20 university clinics, 8 non-university hospitals, 14 centres in private practice). The database aims to include all acromegalic patients in Germany who are cared for and treated at present. Up to December 2005 1543 patients have been entered in a retrospective manner. Data collection is by external monitoring by highly trained study nurses who visit the individual centres. Inclusion is planned to continue at a rate of 500 per year. Starting in 2005 centres are revisited every 3 years at a rate of 500 per year (prospective phase of the registry). Quality of the data has been validated by an independent monitoring team which demonstrated high data concordance. CONCLUSIONS: Initial results of the German Acromegaly Registry show that it was possible to include a large number of patients within 3 years into the registry. Data quality has been validated and shown to be satisfactory. Therefore, the registry will be a useful tool to study long-term morbidity and mortality in a large series of patients.


Assuntos
Acromegalia/epidemiologia , Bases de Dados Factuais , Sistema de Registros , Acromegalia/etiologia , Acromegalia/terapia , Adulto , Idoso , Coleta de Dados/métodos , Feminino , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Projetos de Pesquisa
16.
Am J Primatol ; 68(9): 855-67, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16900501

RESUMO

Concern about emerging and re-emerging diseases plays an increasing role in conservation and management of both captive and free-ranging nonhuman primates (NHPs). Managers and policy makers must formulate conservation plans in an arena plagued by uncertainty, complexity, emotion, and politics. The risk analysis paradigm provides a framework that brings together scientists and policy experts to make better decisions for both people and animals. Risk analysis is a multidisciplinary, science-based process that provides an organized and logical approach for incorporating scientific information into policy development in the real world. By blending four specific goal-oriented stages-hazard identification, risk assessment, risk management, and risk communication-one can logically assess the probability that an adverse event, such as the introduction of an emerging disease into a naïve population, will occur. The following is a review of this process as it pertains to NHP conservation and risks associated with infectious diseases.


Assuntos
Doenças Transmissíveis/veterinária , Conservação dos Recursos Naturais/métodos , Doenças dos Primatas/epidemiologia , Primatas , Zoonoses/epidemiologia , Animais , Animais Selvagens , Doenças Transmissíveis/epidemiologia , Doenças Transmissíveis/microbiologia , Doenças Transmissíveis/transmissão , Humanos , Doenças dos Primatas/microbiologia , Doenças dos Primatas/transmissão , Saúde Pública , Medição de Risco , Gestão de Riscos , Zoonoses/microbiologia , Zoonoses/transmissão
17.
J Nanosci Nanotechnol ; 5(1): 68-78, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15762163

RESUMO

Silica becomes increasingly used in chemical, pharmaceutical, and (nano)technological processes, resulting in an increased demand for well-defined silicas and silica-based materials. The production of highly structured silica from cheap starting materials and under ambient conditions, which is a target for many researchers, is already realized in the formation of diatom biosilica, producing highly hierarchical ordered meso- and macropores silica structures. This notion formed the starting point in our integrative biomolecular and biomimetic study on diatom silicon biomineralization in which we have analyzed silica transformations and structure-direction in polymer-mediated silica syntheses using a combination of (ultra)small-angle X-ray scattering and (cryo)electron microscopy. Using bio-analogous reaction conditions and reagents, such as waterglass and (combinations of) polyethylene oxide (PEO) based polymers, we demonstrate in this review the synthesis of tailor-made mesoporous silicas in which we can, as in biosilica synthesis, control the morphological features of the resulting materials on the nanometer level as well as on the micrometer level.


Assuntos
Biomimética/métodos , Cristalização/métodos , Diatomáceas/metabolismo , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Dióxido de Silício/química , Silício/química , Biomimética/instrumentação , Diatomáceas/ultraestrutura , Minerais/química , Minerais/metabolismo , Tamanho da Partícula , Polímeros/química , Silício/metabolismo , Dióxido de Silício/metabolismo , Propriedades de Superfície
18.
Clin Endocrinol (Oxf) ; 60(6): 750-7, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15163340

RESUMO

OBJECTIVES: There is evidence from recent controlled clinical studies that replacement therapy of hypothyroidism with T4 in combination with a small amount of T3 may improve the well-being of the patients. As the issue is still the subject of controversial discussion, our study was assigned to confirm the superiority of a physiological combination of thyroid hormones (absorbed molar ratio 14 : 1) over T4 alone with regard to mood states and cognitive functioning. DESIGN AND PATIENTS: After a run-in period with the T4 study medication for 4 weeks, a controlled, randomized, double-blind, two-period (each 12 weeks), cross-over study without washout between the treatment periods was performed in 23 hypothyroid patients (three males, 20 females, age 23-69 years, 21 subjects after surgery/radioiodine, two with autoimmune thyroiditis) to compare the effects of the previous individual T4 dose (100-175 micro g) with a treatment in which 5% of the respective T4 dose was substituted by T3. MEASUREMENTS: Standard hormonal characteristics and standardized psychological tests to quantify mood and cognitive performance were measured after the run-in period and at the end of each treatment period. In 12 subjects, the concentration-time profiles of fT3 and fT4 were compared after the last administration of the respective study medication. TSH, fT3 and fT4 were measured with immunological assays. CLINICAL RESULTS: Replacement therapy with T4 and T4/T3 was not different in all steady-state hormonal, metabolic and cardiovascular characteristics except for TSH, which was more suppressed after T4/T3. The efficacy of replacement therapy with the T4/T3 combination was not different from the T4 monotherapy with regard to all psychological test scores describing mood and cognitive functioning of the patients. Mood was even significantly impaired by the T4/T3 combination in eight subjects, with TSH < 0.02 mU/l, compared to patients with normal TSH (Beck Depression Inventory: 8.25 +/- 5.01 vs. 4.07 +/- 5.60, P = 0.026). PHARMACOKINETIC RESULTS: The area under the concentration-time curve (AUC(0-8h)) of fT3 was significantly higher after T4/T3 compared to the T4 monotherapy (42.8 +/- 9.03 pmol x h/l vs. 36.3 +/- 8.50 pmol x h/l, P < 0.05) and was significantly correlated to serum TSH (r(s) = -0.609, P < 0.05). After T4/T3, patients with a history of Graves' disease or autoimmune thyroiditis had significantly higher serum trough levels of fT3 whereas the fT4 concentrations were significantly lower in patients with a nonautoimmune background. CONCLUSION: Replacement therapy of hypothyroidism with T4 plus T3 does not improve mood and cognitive performance compared to the standard T4 monotherapy. There is even a higher risk of signs of subclinical hyperthyroidism associated with impaired well-being of the patients, which is clearly caused by significant fluctuations in the steady-state fT3 serum concentrations.


Assuntos
Hipotireoidismo/tratamento farmacológico , Tiroxina/uso terapêutico , Tri-Iodotironina/uso terapêutico , Adulto , Afeto/efeitos dos fármacos , Idoso , Disponibilidade Biológica , Cognição/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Quimioterapia Combinada , Feminino , Humanos , Hipotireoidismo/sangue , Hipotireoidismo/psicologia , Masculino , Pessoa de Meia-Idade , Estatísticas não Paramétricas , Tireotropina/sangue , Tiroxina/efeitos adversos , Tiroxina/sangue , Falha de Tratamento , Tri-Iodotironina/efeitos adversos , Tri-Iodotironina/sangue
19.
Z Orthop Ihre Grenzgeb ; 141(6): 637-42, 2003.
Artigo em Alemão | MEDLINE | ID: mdl-14679428

RESUMO

AIM: The successful operative stabilization of the shoulder joint is a demanding surgical procedure. The causality of shoulder instability is complex with in some cases multiple lesions in different anatomical structures. The surgeon has to understand the complexity of factors causing instability in order to be therapeutically successful. The aim of the study was to document the intraoperative pathology in revision instability surgery. METHOD: 46 patients with recurrent postoperative instability were included (8 female, 38 male, follow-up > 12 months). After diagnostic arthroscopy an open revision surgery was performed in all cases. RESULTS: In 19 cases (40%) an insufficient surgical procedure was performed (inadequate capsular shift with worn out labral tissue). Selection of an incorrect surgical technique was the reason for revision in 12 patients (25%). Anamnestically 5 patients reported a re-injury, whereas objectively only one patient described an adequate trauma. The most frequent finding was an open rotator interval (persisting Foramen Weitbrecht), which was seen in 22 cases (46%). CONCLUSION: A stable range of motion of the shoulder is achieved by a variety of different factors, which leads in most instances to a combination of pathological changes in case of a dislocated shoulder. To understand the contributing factors of an instable shoulder joint is a necessity to carry out a successful surgical procedure.


Assuntos
Instabilidade Articular/etiologia , Instabilidade Articular/cirurgia , Complicações Pós-Operatórias/etiologia , Luxação do Ombro/etiologia , Luxação do Ombro/cirurgia , Adulto , Causalidade , Feminino , Seguimentos , Humanos , Instabilidade Articular/epidemiologia , Masculino , Erros Médicos/estatística & dados numéricos , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/cirurgia , Recidiva , Reoperação/métodos , Reoperação/estatística & dados numéricos , Fatores de Risco , Luxação do Ombro/epidemiologia , Técnicas de Sutura
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...