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1.
BMC Gastroenterol ; 24(1): 25, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38195453

RESUMO

BACKGROUND: The incidence of inflammatory bowel disease (IBD) in children is on the increase worldwide. Growth disorders are common in pediatric patients with inflammatory bowel disease. The aim of this paper is to investigate anthropometric indicators, including height and weight in children with inflammatory bowel disease in Saxony, one of the German federal states, and to evaluate growth trends in patients by comparing their height and weight with that of healthy children in Germany. METHODS: In Saxony, all children and adolescents with IBD were registered in the Saxon Pediatric IBD Registry from 2000 to 2014. The data used are therefore based on a total area-wide survey over 15 years. For this study, 421 datasets of children and adolescents aged 0-14 years with Crohn's disease (CD) (n = 291) or ulcerative colitis (UC) (n = 130) were analyzed. Z-score and percentile calculations were used to compare differences between IBD patients and the general population. RESULTS: The children with CD or UC (both sexes) had a significant lower weight at diagnosis (the mean weight z-score had negative values) versus the general population. The weight values lay mostly below P50 (the 50th percentile, median), more precisely, mostly between P10 and P50 of the body weight child growth curve for corresponding sexes (KiGGS 2003-2006). The height values of both sexes at diagnosis lay also mostly below P50 (the 50th percentile, median) of the child body growth curve for corresponding sexes (KiGGS 2003-2006), i.e. the mean height z-score was negative. But only the children with CD had a significant lower height, more precisely, mostly between P25 and P50 versus the general population (KIGGS). For children with UC the difference was not significant. CONCLUSION: In pediatric patients with IBD the possibility of growth disturbance, mainly in the form of weight retardation, is very probable.


Assuntos
Colite Ulcerativa , Doença de Crohn , Doenças Inflamatórias Intestinais , Feminino , Masculino , Humanos , Adolescente , Criança , Doenças Inflamatórias Intestinais/epidemiologia , Colite Ulcerativa/epidemiologia , Doença de Crohn/epidemiologia , Pesquisa , Sistema de Registros
2.
Opt Express ; 30(2): 2693-2710, 2022 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-35209404

RESUMO

We demonstrate accurate estimation of generalized optical signal to noise ratio (GOSNR) for wavelength division multiplexed fiber communication systems using an experimentally trained multi-tasking convolutional neural network while simultaneously estimating linear and nonlinear noise contributions. Using dual-polarized 32-GBaud 16QAM DWDM links we extract learnable features from constellation density matrices and accurately estimate GOSNR while simultaneously estimating linear and nonlinear contributions. Estimation of the OSNRASE, OSNRNL and GOSNR are demonstrated with < 0.5 dB mean absolute error. We also assess the universality of our model within the regime of metro networks by cross-training with data from such links comprised of different fiber types. We demonstrate a path to a practical universal training method that includes additional link parameters. The methods do not require contiguous high-speed sampling, additional hardware nor transmission of special symbols or patterns and are readily implemented in deployed systems.

3.
Macromol Rapid Commun ; 41(18): e2000183, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32548919

RESUMO

High-performance polymers such as polymethacrylimides have outstanding properties, for example, a unique strength-to-weight ratio and a high thermal stability, usually coupled to a high glass transition temperature. However, the requirement of high processing temperatures caused by these high glass-transition temperatures is often not desired for melt extrusion processes. Herein, a novel and straightforward imidization process of poly(methacrylic anhydrides) is presented with different ratios of ammonia and N-isopropylamine that is induced by thermal treatment. Therefore, polymethacrylimides with a varying degree of N-substitution, and thus a varying number of hydrogen-bond-donating moieties, are synthesized under facile reaction conditions. An in-depth investigation into the structures obtained with this new methodology is undertaken via a combination of nuclear magnetic resonance spectroscopy (NMR), Fourier-transform infrared spectroscopy (FT-IR), and high-resolution electrospray ionization mass spectrometry (ESI-MS). Additionally, thermal properties of the materials are investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analyses. These latter measurements highlight the key opportunity available with this novel synthesis to tailor the thermal properties of the polymer by providing a clear correlation between hydrogen bond formation, as observed by FT-IR, and the glass transition temperature.


Assuntos
Polímeros , Varredura Diferencial de Calorimetria , Ligação de Hidrogênio , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
4.
PLoS Comput Biol ; 14(7): e1006259, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29969460

RESUMO

Chemical and mechanical pattern formation is fundamental during embryogenesis and tissue development. Yet, the underlying molecular and cellular mechanisms are still elusive in many cases. Most current theories assume that tissue development is driven by chemical processes: either as a sequence of chemical patterns each depending on the previous one, or by patterns spontaneously arising from specific chemical interactions (such as "Turing-patterns"). Within both theories, mechanical patterns are usually regarded as passive by-products of chemical pre-patters. However, several experiments question these theories, and an increasing number of studies shows that tissue mechanics can actively influence chemical patterns during development. In this study, we thus focus on the interplay between chemical and mechanical processes during tissue development. On one hand, based on recent experimental data, we develop new mechanochemical simulation models of evolving tissues, in which the full 3D representation of the tissue appears to be critical for obtaining a realistic mechanochemical behaviour. The presented modelling approach is flexible and numerically studied using state of the art finite element methods. Thus, it may serve as a basis to combine simulations with new experimental methods in tissue development. On the other hand, we apply the developed approach and demonstrate that even simple interactions between tissue mechanics and chemistry spontaneously lead to robust and complex mechanochemical patterns. Especially, we demonstrate that the main contradictions arising in the framework of purely chemical theories are naturally and automatically resolved using the mechanochemical patterning theory.


Assuntos
Fenômenos Biomecânicos , Padronização Corporal , Simulação por Computador , Desenvolvimento Embrionário , Retroalimentação Fisiológica , Modelos Biológicos , Animais , Fenômenos Químicos
5.
Gastroenterology ; 153(2): 410-419.e17, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28461188

RESUMO

BACKGROUND & AIMS: A diagnosis of celiac disease is made based on clinical, genetic, serologic, and duodenal morphology features. Recent pediatric guidelines, based largely on retrospective data, propose omitting biopsy analysis for patients with concentrations of IgA against tissue transglutaminase (IgA-TTG) >10-fold the upper limit of normal (ULN) and if further criteria are met. A retrospective study concluded that measurements of IgA-TTG and total IgA, or IgA-TTG and IgG against deamidated gliadin (IgG-DGL) could identify patients with and without celiac disease. Patients were assigned to categories of no celiac disease, celiac disease, or biopsy required, based entirely on antibody assays. We aimed to validate the positive and negative predictive values (PPV and NPV) of these diagnostic procedures. METHODS: We performed a prospective study of 898 children undergoing duodenal biopsy analysis to confirm or rule out celiac disease at 13 centers in Europe. We compared findings from serologic analysis with findings from biopsy analyses, follow-up data, and diagnoses made by the pediatric gastroenterologists (celiac disease, no celiac disease, or no final diagnosis). Assays to measure IgA-TTG, IgG-DGL, and endomysium antibodies were performed by blinded researchers, and tissue sections were analyzed by local and blinded reference pathologists. We validated 2 procedures for diagnosis: total-IgA and IgA-TTG (the TTG-IgA procedure), as well as IgG-DGL with IgA-TTG (TTG-DGL procedure). Patients were assigned to categories of no celiac disease if all assays found antibody concentrations <1-fold the ULN, or celiac disease if at least 1 assay measured antibody concentrations >10-fold the ULN. All other cases were considered to require biopsy analysis. ULN values were calculated using the cutoff levels suggested by the test kit manufacturers. HLA typing was performed for 449 participants. We used models that considered how specificity values change with prevalence to extrapolate the PPV and NPV to populations with lower prevalence of celiac disease. RESULTS: Of the participants, 592 were found to have celiac disease, 345 were found not to have celiac disease, and 24 had no final diagnosis. The TTG-IgA procedure identified patients with celiac disease with a PPV of 0.988 and an NPV of 0.934; the TTG-DGL procedure identified patients with celiac disease with a PPV of 0.988 and an NPV of 0.958. Based on our extrapolation model, we estimated that the PPV and NPV would remain >0.95 even at a disease prevalence as low as 4%. Tests for endomysium antibodies and HLA type did not increase the PPV of samples with levels of IgA-TTG ≥10-fold the ULN. Notably, 4.2% of pathologists disagreed in their analyses of duodenal morphology-a rate comparable to the error rate for serologic assays. CONCLUSIONS: In a prospective study, we validated the TTG-IgA procedure and the TTG-DGL procedure in identification of pediatric patients with or without celiac disease, without biopsy. German Clinical Trials Registry no.: DRKS00003854.


Assuntos
Autoanticorpos/sangue , Doença Celíaca/diagnóstico , Proteínas de Ligação ao GTP/imunologia , Gliadina/imunologia , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Transglutaminases/imunologia , Autoanticorpos/imunologia , Biópsia , Doença Celíaca/imunologia , Doença Celíaca/patologia , Criança , Pré-Escolar , Duodeno/patologia , Europa (Continente) , Feminino , Humanos , Lactente , Masculino , Valor Preditivo dos Testes , Estudos Prospectivos , Proteína 2 Glutamina gama-Glutamiltransferase , Sensibilidade e Especificidade , Testes Sorológicos/métodos
6.
Clin Gastroenterol Hepatol ; 16(9): 1442-1449.e5, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29654912

RESUMO

BACKGROUND & AIMS: Celiac disease can be identified by a serologic test for IgA against tissue transglutaminase (IgA-TTG) in a large proportion of children. However, the increased concentrations of antibody rarely normalize within the months after children are placed on a gluten-free diet (GFD). Early serologic predictors of sufficient adherence to GFD are required for optimal treatment. METHODS: In a prospective study, we observed the response to a GFD in 345 pediatric patients (67% girls; mean age, 8.4 y) who underwent duodenal biopsy to confirm or refute celiac disease from October 2012 through December 2015. Baseline serum samples were tested centrally for IgA-TTG and IgG against deamidated gliadin. Follow-up serologic analyses of children on a GFD were performed about 3 months later. RESULTS: The geometric mean concentration of IgA-TTG decreased from 72.4-fold to 5.2-fold the upper limit of normal (ULN), or by a factor of 14.0 (95% CI, 12.0-16.4). A substantial response (defined as a larger change than the typical variation in patients not on a GFD) was observed in 80.6% of the children. Only 28.1% of patients had a substantial response in the concentration of IgG against deamidated gliadin. Concentration of IgA-TTG remained above 1-fold the ULN in 83.8% of patients, and above 10-fold the ULN in 26.6% of patients with a substantial response. CONCLUSIONS: Serum concentration of IgA-TTG decreases substantially in most children with celiac disease within 3 months after they are placed on a GFD, but does not normalize in most. This information on changes in antibody concentrations can be used to assess patient response to the diet at short-term follow-up evaluations. Patients with a substantial response to a GFD often still have high antibody levels after 3 months. German Clinical Trials Registry no. DRKS00003854.


Assuntos
Autoanticorpos/sangue , Doença Celíaca/patologia , Doença Celíaca/terapia , Dieta Livre de Glúten , Adolescente , Análise Química do Sangue , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Imunoglobulina A/sangue , Lactente , Masculino , Estudos Prospectivos , Fatores de Tempo
7.
J Math Biol ; 72(4): 973-996, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26385578

RESUMO

In this paper, a model is developed for the evolution of plaques in arteries, which is one of the main causes for the blockage of blood flow. Plaque rupture and spread of torn-off material may cause closures in the down-stream vessel system and lead to ischemic brain or myocardial infarctions. The model covers the flow of blood and its interaction with the vessel wall. It is based on the assumption that the penetration of monocytes from the blood flow into the vessel wall, and the accumulation of foam cells increasing the volume, are main factors for the growth of plaques. The dynamics of the vessel wall is governed by a deformation gradient, which is given as composition of a purely elastic tensor, and a tensor modeling the biologically caused volume growth. An equation for the evolution of the metric is derived quantifying the changing geometry of the vessel wall. To calculate numerically the solutions of the arising free boundary problem, the model system of partial differential equations is transformed to an ALE (Arbitrary Lagrangian-Eulerian) formulation, where all equations are given in fixed domains. The numerical calculations are using newly developed algorithms for ALE systems. The results of the simulations, obtained for realistic system parameters, are in good qualitative agreement with observations. They demonstrate that the basic modeling assumption can be justified. The increase of stresses in the vessel wall can be computed. Medical treatment tries to prevent critical stress values, which may cause plaque rupture and its consequences.


Assuntos
Modelos Cardiovasculares , Placa Aterosclerótica/etiologia , Algoritmos , Artérias/fisiopatologia , Fenômenos Biomecânicos , Velocidade do Fluxo Sanguíneo , Simulação por Computador , Hemorreologia , Humanos , Hidrodinâmica , Conceitos Matemáticos , Placa Aterosclerótica/fisiopatologia
8.
Opt Express ; 22(22): 27077-85, 2014 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-25401858

RESUMO

The possibility of all-optical phase-preserving amplitude regeneration for star-8QAM is demonstrated using a modified nonlinear optical loop mirror. Experiments show a reduction in amplitude noise on both amplitude levels simultaneously, considering two different types of signal distortions: deterministic low-frequency amplitude modulation and broadband amplitude noise. Furthermore, using this amplitude regeneration, the robustness against nonlinear phase noise from fiber nonlinearity in a transmission line is increased. The scheme suppresses the conversion of amplitude noise to nonlinear phase noise. This is shown for simultaneous amplitude regeneration of the two amplitude states as well as for amplitude regeneration of the high-power states only. If the transmission is limited by nonlinear phase noise, single-level operation at the more critical higher-power state will benefit because of the wider plateau region. Numerical simulations confirm the experimental results.

9.
Opt Express ; 22(22): 27381-91, 2014 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-25401887

RESUMO

We present experimental and numerical investigations of Kerr nonlinearity compensation in a 400-km standard single-mode fiber link with distributed Raman amplification with backward pumping. A dual-pump polarization-independent fiber-based optical parametric amplifier is used for mid-link spectral inversion of 5 × 28-GBd polarization-multiplexed 16-QAM signals. Signal quality factor (Q-factor) improvements of 1.1 dB and 0.8 dB were obtained in the cases of a single-channel and a five-channel wavelength-division multiplexing (WDM) system, respectively. The experimental results are compared to numerical simulations with good agreement. It is also shown with simulations that a maximum transmission reach of 2400 km enabled by the optical phase conjugator is possible for the WDM signal.

10.
J Surg Res ; 189(2): 340-7, 2014 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-24726059

RESUMO

BACKGROUND: Tissue-engineered blood vessels (TEBVs) represent an innovative approach for overcoming reconstructive problems associated with vascular diseases by providing small-caliber vascular grafts. This study aimed to evaluate a novel biomaterial of bacterially synthesized cellulose (BC) as a potential scaffold for small-diameter TEBV. METHODS: Small-diameter blood vessels with a supramolecular fiber network structure consisting of tubular hydrogels from biodesigned cellulose were created using Gluconacetobacter strains and Matrix reservoir technology. BC tubes (length: 100 mm, inner diameter: 4.0-5.0 mm) were applied to replace the carotid arteries of 10 sheep for a period of 3 mo to gain further insights into (a) functional (in vivo) performance, (b) ability of providing a scaffold for the neoformation of a vascular wall and (c) their proinflammatory potential, and the (d) technical feasibility of the procedure. RESULTS: Preoperative analysis revealed a bursting strength of the grafts of approximately 800 mm Hg and suture retention strength of 4-5 N. Postexplantation analysis showed a patency rate of 50% (n = 5) and physiological performance of the patent grafts at 4, 8, and 12 wk postoperatively, compared with native arteries. Histologic analysis revealed a neoformation of a vascular wall-like structure along the BC scaffold consisting of immigrated vascular smooth muscle cells and a homogeneous endothelialization of the inner graft surface without signs of prothrombogenic or inflammatory potential. Scanning electron microscopy revealed a confluent luminal endothelial cell layer and the immigration of vascular smooth muscle cells into the BC matrix. CONCLUSIONS: BC grafts provide a scaffold for the neoformation of a three-layered vascular wall exhibit attractive properties for their use in future TEBV programs for cardiovascular surgery.


Assuntos
Implante de Prótese Vascular , Prótese Vascular , Celulose , Gluconacetobacter xylinus , Engenharia Tecidual , Animais , Arteríolas , Estudos de Viabilidade , Feminino , Reação a Corpo Estranho , Teste de Materiais , Ovinos , Alicerces Teciduais , Grau de Desobstrução Vascular
11.
Cent Eur J Public Health ; 22(1): 48-53, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24844107

RESUMO

OBJECTIVE: Helicobacter pylori (H.p.) infections play a very important role in the development of ulcerations and malignancies of the gastrointestinal tract. It is assumed that the primary infection occurs during childhood, depending on numerous environmental factors among them hygiene and social status. Our aim was to determine whether treatment with antibiotics affects the persistence of H.p. infection. METHODS: In 2006, we conducted an epidemiological study among all grade 8 students in the city of Leipzig (mean age 14.6 years). To determine the prevalence of H.p. infection, a voluntary H.p. test (13C-urea breath test) was performed in all participants. RESULTS: The H.p. prevalence was 6.3% (N = 1,598). A significant difference was found between those students who had been treated with an antibiotic at least once prior to the test and those who had never received any antibiotics (4.0% and 11.1%, respectively, p < 0.001). H.p. prevalence decreased with increasing numbers of antibiotic treatments. CONCLUSION: In adolescence, treatment with "non-H.p. specific" antibiotics appears to significantly affect H.p. prevalence. Moreover, the actual persistence of H.p. in "chronic persistent" H.p. infections appears to fluctuate at least in younger years. Thus, any "non-H.p. specific" antibiotic treatment should be considered in the diagnosis and treatment of H.p. infections and should be taken into account as an important confounder in future epidemiological studies.


Assuntos
Antibacterianos/uso terapêutico , Infecções por Helicobacter/epidemiologia , Helicobacter pylori/isolamento & purificação , Adolescente , Antibacterianos/administração & dosagem , Testes Respiratórios/métodos , Emigrantes e Imigrantes/estatística & dados numéricos , Feminino , Alemanha/epidemiologia , Infecções por Helicobacter/diagnóstico , Helicobacter pylori/efeitos dos fármacos , Humanos , Modelos Logísticos , Masculino , Prevalência , Fatores Socioeconômicos , Inquéritos e Questionários , Ureia/análise
12.
Emerg Microbes Infect ; 13(1): 2350168, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38687703

RESUMO

ABSTRACTBorna disease virus 1 (BoDV-1) was just recently shown to cause predominantly fatal encephalitis in humans. Despite its rarity, bornavirus encephalitis (BVE) can be considered a model disease for encephalitic infections caused by neurotropic viruses and understanding its pathomechanism is of utmost relevance. Aim of this study was to compare the extent and distribution pattern of cerebral inflammation with the clinical course of disease, and individual therapeutic procedures. For this, autoptic brain material from seven patients with fatal BVE was included in this study. Tissue was stained immunohistochemically for pan-lymphocytic marker CD45, the nucleoprotein of BoDV-1, as well as glial marker GFAP and microglial marker Iba1. Sections were digitalized and counted for CD45-positive and BoDV-1-positive cells. For GFAP and Iba1, a semiquantitative score was determined. Furthermore, detailed information about the individual clinical course and therapy were retrieved and summarized in a standardized way. Analysis of the distribution of lymphocytes shows interindividual patterns. In contrast, when looking at the BoDV-1-positive glial cells and neurons, a massive viral involvement in the brain stem was noticeable. Three of the seven patients received early high-dose steroids, which led to a significantly lower lymphocytic infiltration of the central nervous tissue and a longer survival compared to the patients who were treated with steroids later in the course of disease. This study highlights the potential importance of early high-dose immunosuppressive therapy in BVE. Our findings hint at a promising treatment option which should be corroborated in future observational or prospective therapy studies.ABBREVIATIONS: BoDV-1: Borna disease virus 1; BVE: bornavirus encephalitis; Cb: cerebellum; CNS: central nervous system; FL: frontal lobe; GFAP: glial fibrillary acid protein; Hc: hippocampus; Iba1: ionized calcium-binding adapter molecule 1; Iba1act: general activation of microglial cells; Iba1nod: formation of microglial nodules; IL: insula; Me: mesencephalon; Mo: medulla oblongata; OL: occipital lobe; pASS: per average of 10 screenshots; patearly: patients treated with early high dose steroid shot; patlate: patients treated with late or none high dose steroid shot; Po: pons; So: stria olfactoria; Str: striatum.


Assuntos
Encéfalo , Humanos , Masculino , Feminino , Encéfalo/virologia , Encéfalo/imunologia , Doença de Borna/tratamento farmacológico , Doença de Borna/virologia , Linfócitos/imunologia , Proteínas dos Microfilamentos/metabolismo , Antígenos Comuns de Leucócito/metabolismo , Proteína Glial Fibrilar Ácida/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Terapia de Imunossupressão , Vírus da Doença de Borna/fisiologia , Encefalite Viral/tratamento farmacológico , Encefalite Viral/virologia , Encefalite Viral/imunologia , Neuroglia/virologia , Neuroglia/metabolismo
13.
Space Sci Rev ; 220(5): 51, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38948073

RESUMO

The Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) is a dual-frequency ice-penetrating radar (9 and 60 MHz) onboard the Europa Clipper mission. REASON is designed to probe Europa from exosphere to subsurface ocean, contributing the third dimension to observations of this enigmatic world. The hypotheses REASON will test are that (1) the ice shell of Europa hosts liquid water, (2) the ice shell overlies an ocean and is subject to tidal flexing, and (3) the exosphere, near-surface, ice shell, and ocean participate in material exchange essential to the habitability of this moon. REASON will investigate processes governing this material exchange by characterizing the distribution of putative non-ice material (e.g., brines, salts) in the subsurface, searching for an ice-ocean interface, characterizing the ice shell's global structure, and constraining the amplitude of Europa's radial tidal deformations. REASON will accomplish these science objectives using a combination of radar measurement techniques including altimetry, reflectometry, sounding, interferometry, plasma characterization, and ranging. Building on a rich heritage from Earth, the moon, and Mars, REASON will be the first ice-penetrating radar to explore the outer solar system. Because these radars are untested for the icy worlds in the outer solar system, a novel approach to measurement quality assessment was developed to represent uncertainties in key properties of Europa that affect REASON performance and ensure robustness across a range of plausible parameters suggested for the icy moon. REASON will shed light on a never-before-seen dimension of Europa and - in concert with other instruments on Europa Clipper - help to investigate whether Europa is a habitable world.

14.
Radiology ; 268(3): 710-8, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23630311

RESUMO

PURPOSE: To test the image features that may be useful in predicting the visually lossless thresholds (VLTs) of body computed tomographic (CT) images for Joint Photographic Experts Group 2000 (JPEG2000) compression. MATERIALS AND METHODS: The institutional review board approved this study, with a waiver of informed patient consent. One hundred body CT studies obtained in different patients by using five scanning protocols were obtained, and 100 images, each of which was selected from each of the 100 studies, were collected. Five radiologists independently determined the VLT of each image for JPEG2000 compression by using the QUEST algorithm. The 100 images were randomly divided into two data sets-the training set (50 images) and the testing set (50 images)-and the division was repeated 200 times. For each of the 200 divisions, a multiple linear regression model was constructed on a training set and tested on a testing set regarding each of five image features-standard deviation of image intensity, image entropy, relative percentage of low-frequency (LF) energy, variation in high-frequency (HF) energy, and visual complexity-as independent variables and considering the VLTs determined with the median value of the radiologists' responses as a dependent variable. The root mean square residual and intraclass correlation coefficient (ICC) for the 200 divisions between the VLTs predicted by the models and those determined by radiologists were compared between the models by using repeated-measures analysis of variance with post-hoc comparisons. RESULTS: Mean root-mean-square residuals for multiple linear regression models constructed with variation in HF energy (1.20 ± 0.10 [standard deviation]) and visual complexity (1.09 ± 0.07) were significantly lower than those for standard deviation of image intensity (1.65 ± 0.13), image entropy (1.63 ± 0.14), and relative percentage of LF energy (1.58 ± 0.12) (P < .01). ICCs for variation in HF energy (0.64 ± 0.05) and visual complexity (0.71 ± 0.04) were significantly higher than those for standard deviation of image intensity (0.04 ± 0.02), image entropy (0.05 ± 0.02), and relative percentage of LF energy (0.20 ± 0.04) (P < .01). CONCLUSION: Among the five tested image features, variation in HF energy and visual complexity were the most promising in predicting the VLTs of body CT images for JPEG2000 compression.


Assuntos
Algoritmos , Compressão de Dados/métodos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Processamento de Sinais Assistido por Computador , Tomografia Computadorizada por Raios X/métodos , Imagem Corporal Total/métodos , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Projetos Piloto , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
15.
Langmuir ; 29(49): 15463-73, 2013 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-24266499

RESUMO

The potential of 2,2';3,2″-terthiophene (3T) as branching units in 3D copolymers is presented with EDOT as an example comonomer. Branched EDOT/3T polythiophenes were prepared by electropolymerization, and their electrochemical and optical properties are discussed. Two different approaches were employed: (i) the direct electropolymerization of a novel branched thiophene monomer (3TE3) consisting of a 3T core that contains three outer EDOT end groups and (ii) the electrochemical copolymerization of a EDOT/3T mixture in different ratios from [1:1] to [1:10]. Cyclic voltammetric and vis spectrometric experiments show that the EDOT content within the polymer has a strong influence on the electronic properties of the material: with increasing EDOT content, the HOMO-LUMO gap is decreased. To prove copolymer formation of EDOT and 3T, chemically synthesized reference copolymers of EDOT and 3T were prepared by oxidative coupling using FeCl3, and their optical and electronic properties were compared to those of the electrodeposited films. In addition, the copolymer formation is indicated by the comparison of the electrochemical and spectroscopic results with those of the homopolymers P3T and PEDOT.

16.
Bioorg Med Chem ; 21(10): 2710-4, 2013 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-23562373

RESUMO

A NMR method related to 2D CH correlation with an additional double quantum filter for (31)P spin coupling was employed to follow the reaction kinetics of the two anomers of glucose during phosphorylation catalyzed by the enzyme yeast hexokinase. The kinetic parameters according to Michaelis-Menten for these reactions have been determined and it is shown that the ß-anomer of glucose is phosphorylated faster by a factor of 1.4 versus the α-anomer. Use of human liver glucokinase as an enzyme yields more complex kinetics.


Assuntos
Glucose/química , Ressonância Magnética Nuclear Biomolecular/métodos , Glucose/metabolismo , Hexoquinase/metabolismo , Humanos , Fosforilação , Estereoisomerismo , Especificidade por Substrato
17.
PLoS One ; 18(6): e0287860, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37384664

RESUMO

OBJECTIVE: In Saxony, the incidence of Crohn's disease (CD) in children and adolescents increased significantly from 3.3 per 100,000 person-years in 2000 to 5.1 in 2014. The aim of this study was to describe the initial characteristics and the clinical course of CD in children and adolescents and to identify drug treatment options associated with an advantage for a mild course or remission. METHODS: Clinical data were collected from patients who suffered from inflammatory bowel disease (IBD) and were recruited in the Saxon Pediatric IBD-Registry. All children newly diagnosed with CD in this registry in Saxony between 2000 and 2014 were included in this registry study. Characteristics such as age, disease location and extra-intestinal manifestations at diagnosis were accessed. The severity level of the disease at diagnosis as well as at follow-up were analysed by PCDAI index. Patients were divided into 3 groups according to length of follow-up: 1-3 years, 4-6 years and 7-9 years after diagnosis. A logistic regression model was conducted to examine which baseline parameters are associated with disease progression. RESULTS: There were 338 children and adolescents with CD included in this registry study. At diagnosis, the median age of patients was 12.0 (0.7-14.9), 61.5% (n = 208) of the patients were male. The most common disease location observed in pediatric CD patients was the L3 (55%, n = 176). Patients aged 10-14 years were significantly more likely to present an L2 than patients aged 0-4 years (80.3%, n = 53 vs. 19.7%, n = 13, p = 0.01). During the follow-up, data from 71.3% (n = 241) othe patients were available. Disease activity measured by PCDAI decreased in 47.7% (n = 115) of the patients, 40.7% (n = 98) of the patients were stable and increased in 11.6% (n = 28) of the patients. Patients with intermediate/severe disease at onset were more likely to have an active disease at the end of follow up, too (p = 0.00). Logistic regression analysis of the initial characteristics showed that the age at diagnosis, gender, initial location and initial extra-intestinal manifestation are not associated with the progression of the disease (p>0.05). Furthermore, drug treatment options could be identified from our data, which are associated with benefits for a milder course or remission. CONCLUSION: From 2000 to 2014, the health status of most pediatric patients with CD had improved or remained stable. Initial characteristics including age at diagnosis, initial localization and initial extra-intestinal manifestation are not associated with the progression of the disease, only the initial activity by PCDAI.


Assuntos
Doença de Crohn , Doenças Inflamatórias Intestinais , Humanos , Adolescente , Criança , Masculino , Feminino , Doença de Crohn/diagnóstico , Doença de Crohn/tratamento farmacológico , Doença de Crohn/epidemiologia , Alemanha/epidemiologia , Sistema de Registros , Progressão da Doença
18.
J Am Chem Soc ; 134(1): 43-6, 2012 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-22171620

RESUMO

The synthesis of ionically functionalized branched polythiophenes with either carboxylic acid (anionic, P3T-COOH) or methylimidazolium (cationic, P3T-MIM) end groups is presented. Due to the large number of end groups present in the polymer, the functionalization has a major impact on the solubility of the polymers. In the case of P3T-COOH, the polymer shows a fully reversible phase transfer between organic solvents and water, depending on the pH. Remarkably, the ionic-liquid-modified polymer P3T-MIM is soluble in a room-temperature ionic liquid. The absorption properties are unaffected by the functional end groups.

19.
Opt Express ; 20(12): 13100-7, 2012 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-22714337

RESUMO

In this paper we present four-wave mixing (FWM) based parametric conversion experiments in p-i-n diode assisted silicon-on-insulator (SOI) nano-rib waveguides using continuous-wave (CW) light around 1550 nm wavelength. Using a reverse biased p-i-n waveguide diode we observe an increase of the wavelength conversion efficiency of more than 4.5 dB compared to low loss nano-rib waveguides without p-i-n junction, achieving a peak efficiency of -1 dB. Conversion efficiency improves also by more than 7 dB compared to previously reported experiments deploying 1.5 µm SOI waveguides with p-i-n structure. To the best of our knowledge, the observed peak conversion efficiency of -1dB is the highest CW efficiency in SOI reported so far.

20.
J Pediatr Gastroenterol Nutr ; 55(1): 21-5, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22249805

RESUMO

OBJECTIVE: Assays for antibodies against native gliadin (anti-nGli) are still often assumed to perform better in the diagnosis of coeliac disease in young children than tests for antibodies to deamidated gliadin (anti-dGli), tissue transglutaminase (anti-tTG), and endomysium (EmA). We compared the performance of assays for anti-nGli, anti-dGli, anti-tTG, and EmA in this age group. METHODS: We investigated retrospectively 184 children (42 with coeliac disease under normal diet and 142 controls) up to 2 years of age. Immunoglobulin (Ig) A- and IgG-anti-dGli, IgA- and IgG-anti-nGli, IgA- and IgG-anti-tTG, and IgA-EmA were measured in serum. Areas under receiver operating characteristics curves, sensitivities, specificities, positive and negative predictive values, positive and negative likelihood ratios, as well as diagnostic odds ratios were calculated. RESULTS: From all of the tests investigated, only assays for IgG-anti-dGli, IgA-anti-tTG, and IgA-EmA had high specificity (≥ 0.96) connected with high sensitivity (≥ 0.86), with high positive predictive values (≥ 0.52 and ≥ 0.69 at pretest probabilities of 0.05 and 0.1, respectively) and negative predictive values (≥ 0.99 and ≥ 0.98 at pretest probabilities of 0.05 and 0.1, respectively). These assays also showed high positive likelihood ratio (≥ 24) at low negative likelihood ratio (≤ 0.15) and high diagnostic odds ratios (≥ 136). CONCLUSIONS: Our results do not support the use of assays of anti-nGli to diagnose coeliac disease in young children. IgA-anti-tTG, IgA-EmA, and IgG-anti-dGli perform better than anti-nGli.


Assuntos
Doença Celíaca/diagnóstico , Gliadina/imunologia , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Área Sob a Curva , Doença Celíaca/imunologia , Distribuição de Qui-Quadrado , Pré-Escolar , Feminino , Humanos , Lactente , Funções Verossimilhança , Masculino , Músculos/imunologia , Razão de Chances , Valor Preditivo dos Testes , Curva ROC , Estudos Retrospectivos , Transglutaminases/imunologia
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