Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 36
Filtrar
1.
Clin Orthop Relat Res ; 482(2): 244-256, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37646744

RESUMO

BACKGROUND: The interpretation of patient-reported outcomes requires appropriate comparison data. Currently, no patient-specific reference data exist for the Patient-Reported Outcome Measurement Information System (PROMIS) Physical Function (PF), Upper Extremity (UE), and Pain Interference (PI) scales for individuals 50 years and older. QUESTIONS/PURPOSES: (1) Can all PROMIS PF, UE, and PI items be used for valid cross-country comparisons in these domains among the United States, the United Kingdom, and Germany? (2) How are age, gender, and country related to PROMIS PF, PROMIS UE, and PROMIS PI scores? (3) What is the relationship of age, gender, and country across individuals with PROMIS PF, PROMIS UE, and PROMIS PI scores ranging from very low to very high? METHODS: We conducted telephone interviews to collect custom PROMIS PF (22 items), UE (eight items), and PI (eight items) short forms, as well as sociodemographic data (age, gender, work status, and education level), with participants randomly selected from the general population older than 50 years in the United States (n = 900), United Kingdom (n = 905), and Germany (n = 921). We focused on these individuals because of their higher prevalence of surgeries and lower physical functioning. Although response rates varied across countries (14% for the United Kingdom, 22% for Germany, and 12% for the United States), we used existing normative data to ensure demographic alignment with the overall populations of these countries. This helped mitigate potential nonresponder bias and enhance the representativeness and validity of our findings. We investigated differential item functioning to determine whether all items can be used for valid crosscultural comparisons. To answer our second research question, we compared age groups, gender, and countries using median regressions. Using imputation of plausible values and quantile regression, we modeled age-, gender-, and country-specific distributions of PROMIS scores to obtain patient-specific reference values and answer our third research question. RESULTS: All items from the PROMIS PF, UE, and PI measures were valid for across-country comparisons. We found clinically meaningful associations of age, gender, and country with PROMIS PF, UE, and PI scores. With age, PROMIS PF scores decreased (age ß Median = -0.35 [95% CI -0.40 to -0.31]), and PROMIS UE scores followed a similar trend (age ß Median = -0.38 [95% CI -0.45 to -0.32]). This means that a 10-year increase in age corresponded to a decline in approximately 3.5 points for the PROMIS PF score-a value that is approximately the minimum clinically important difference (MCID). Concurrently, we observed a modest increase in PROMIS PI scores with age, reaching half the MCID after 20 years. Women in all countries scored higher than men on the PROMIS PI and 1 MCID lower on the PROMIS PF and UE. Additionally, there were higher T-scores for the United States than for the United Kingdom across all domains. The difference in scores ranged from 1.21 points for the PROMIS PF to a more pronounced 3.83 points for the PROMIS UE. Participants from the United States exhibited up to half an MCID lower T-scores than their German counterparts for the PROMIS PF and PROMIS PI. In individuals with high levels of physical function, with each 10-year increase in age, there could be a decrease of up to 4 points in PROMIS PF scores. Across all levels of upper extremity function, women reported lower PROMIS UE scores than men by an average of 5 points. CONCLUSION: Our study provides age-, gender-, and country-specific reference values for PROMIS PF, UE, and PI scores, which can be used by clinicians, researchers, and healthcare policymakers to better interpret patient-reported outcomes and provide more personalized care. These findings are particularly relevant for those collecting patient-reported outcomes in their clinical routine and researchers conducting multinational studies. We provide an internet application ( www.common-metrics.org/PROMIS_PF_and_PI_Reference_scores.php ) for user-friendly accessibility in order to perform age, gender, and country conversions of PROMIS scores. Population reference values can also serve as comparators to data collected with other PROMIS short forms or computerized adaptive tests. LEVEL OF EVIDENCE: Level II, diagnostic study.


Assuntos
Medidas de Resultados Relatados pelo Paciente , Extremidade Superior , Feminino , Humanos , Masculino , Extremidade Inferior , Diferença Mínima Clinicamente Importante , Dor , Pessoa de Meia-Idade
2.
Qual Life Res ; 32(3): 749-758, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36617606

RESUMO

PURPOSE: The assessment of health-related quality of life (HRQOL) measured via patient-reported outcomes (PROs) is a key component in clinical trials and increasingly used in clinical routine worldwide. Two PRO measures (PROMs) that share the same definition of health and report outcomes on a comparable T-metric anchored to general population samples are the PROMIS-29 and the EORTC QLQ-C30. In this study, we investigate the empirical agreement of these underlying concepts. METHODS: We collected PROMIS-29 and EORTC QLQ-C30 data from 1,478 female patients at a breast cancer outpatient centre. We calculated descriptive statistics and correlations between the subscales of both instruments. We performed exploratory (EFA) and confirmatory factor analysis (CFA) in randomly split subsamples in order to assess the underlying psychometric structure of both instruments. RESULTS: The cohort (mean age = 47.4, ± 14.49) reported comparable mean HRQOL scores between the corresponding subscales of both instruments similar to general population reference values. Correlation between the corresponding subscales of both instruments ranged between 0.59 (Social Role) and 0.78 (Physical Functioning). Both an exploratory and a theoretically driven confirmatory factor analysis provided further support for conceptual agreement of the scales. CONCLUSION: EORTC QLQ-C30 and PROMIS-29 showed similar scores and satisfactory agreement in conceptional and statistical analysis. This suggests that the underlying conceptualization of health is reasonably close. Hence, the development of score transformation algorithms or calibration of both instruments on common scales could prospectively increase the comparability of clinical and research PRO data collected with either instrument.


Assuntos
Neoplasias da Mama , Qualidade de Vida , Humanos , Feminino , Qualidade de Vida/psicologia , Algoritmos , Calibragem , Análise Fatorial , Inquéritos e Questionários
3.
Angew Chem Int Ed Engl ; 60(39): 21583-21591, 2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34228886

RESUMO

Tin is the frontrunner for substituting toxic lead in perovskite solar cells. However, tin suffers the detrimental oxidation of SnII to SnIV . Most of reported strategies employ SnF2 in the perovskite precursor solution to prevent SnIV formation. Nevertheless, the working mechanism of this additive remains debated. To further elucidate it, we investigate the fluoride chemistry in tin halide perovskites by complementary analytical tools. NMR analysis of the precursor solution discloses a strong preferential affinity of fluoride anions for SnIV over SnII , selectively complexing it as SnF4 . Hard X-ray photoelectron spectroscopy on films shows the lower tendency of SnF4 than SnI4 to get included in the perovskite structure, hence preventing the inclusion of SnIV in the film. Finally, small-angle X-ray scattering reveals the strong influence of fluoride on the colloidal chemistry of precursor dispersions, directly affecting perovskite crystallization.

4.
J Am Chem Soc ; 142(5): 2364-2374, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31917562

RESUMO

Halide perovskites are a strong candidate for the next generation of photovoltaics. Chemical doping of halide perovskites is an established strategy to prepare the highest efficiency and most stable perovskite-based solar cells. In this study, we unveil the doping mechanism of halide perovskites using a series of alkaline earth metals. We find that low doping levels enable the incorporation of the dopant within the perovskite lattice, whereas high doping concentrations induce surface segregation. The threshold from low to high doping regime correlates to the size of the doping element. We show that the low doping regime results in a more n-type material, while the high doping regime induces a less n-type doping character. Our work provides a comprehensive picture of the unique doping mechanism of halide perovskites, which differs from classical semiconductors. We proved the effectiveness of the low doping regime for the first time, demonstrating highly efficient methylammonium lead iodide based solar cells in both n-i-p and p-i-n architectures.

5.
Am J Med Genet A ; 170(3): 728-33, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26640080

RESUMO

Using whole-exome sequencing, we identified a homozygous acceptor splice-site mutation in intron 6 of the KATNB1 gene in a patient from a consanguineous Turkish family who presented with congenital microcephaly, lissencephaly, short stature, polysyndactyly, and dental abnormalities. cDNA analysis revealed complete loss of the natural acceptor splice-site resulting either in the usage of an alternative, exonic acceptor splice-site inducing a frame-shift and premature protein truncation or, to a minor extent, in complete skipping of exon 7. Both effects most likely lead to complete loss of KATNB1 function. Homozygous and compound heterozygous mutations in KATNB1 have very recently been described as a cause of microcephaly with brain malformations and seizures. We extend the KATNB1 associated phenotype by describing a syndrome characterized by primordial dwarfism, lissencephaly, polysyndactyly, and dental anomalies, which is caused by a homozygous truncating KATNB1 mutation.


Assuntos
Nanismo/genética , Homozigoto , Lisencefalia/genética , Microcefalia/genética , Mutação , Sindactilia/genética , Pré-Escolar , Análise Mutacional de DNA , Nanismo/diagnóstico , Exoma , Feminino , Ordem dos Genes , Loci Gênicos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lisencefalia/diagnóstico , Imageamento por Ressonância Magnética , Microcefalia/diagnóstico , Linhagem , Fenótipo , Sindactilia/diagnóstico , Síndrome
6.
Opt Express ; 21(7): 7858-67, 2013 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-23571876

RESUMO

This study presents a novel numerical model for laser ablation and laser damage in glass including beam propagation and nonlinear absorption of multiple incident ultrashort laser pulses. The laser ablation and damage in the glass cutting process with a picosecond pulsed laser was studied. The numerical results were in good agreement with our experimental observations, thereby revealing the damage mechanism induced by laser ablation. Beam propagation effects such as interference, diffraction and refraction, play a major role in the evolution of the crater structure and the damage region. There are three different damage regions, a thin layer and two different kinds of spikes. Moreover, the electronic damage mechanism was verified and distinguished from heat modification using the experimental results with different pulse spatial overlaps.


Assuntos
Vidro/química , Vidro/efeitos da radiação , Lasers , Modelos Químicos , Simulação por Computador , Doses de Radiação , Espalhamento de Radiação
7.
Cancer Cell ; 8(3): 227-39, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16169467

RESUMO

Chromosomal instability in human breast cancer is known to take place before mammary neoplasias display morphological signs of invasion. We describe here the unexpected finding of a tumor cell population with normal karyotypes isolated from bone marrow of breast cancer patients. By analyzing the same single cells for chromosomal aberrations, subchromosomal allelic losses, and gene amplifications, we confirmed their malignant origin and delineated the sequence of genomic events during breast cancer progression. On this trajectory of genomic progression, we identified a subpopulation of patients with very early HER2 amplification. Because early changes have the highest probability of being shared by genetically unstable tumor cells, the genetic characterization of disseminated tumor cells provides a novel rationale for selecting patients for targeted therapies.


Assuntos
Células da Medula Óssea/patologia , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Queratinas/genética , Apoptose , Instabilidade Cromossômica/genética , Mapeamento Cromossômico , Feminino , Marcadores Genéticos , Humanos , Cariotipagem , Perda de Heterozigosidade
8.
Sci Rep ; 13(1): 22498, 2023 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-38110426

RESUMO

During the SARS-CoV-2 pandemic, the German healthcare system faced challenges of efficiently allocating testing resources. To address this, we developed an open-source personalized recommendation system (PRS) called "CovApp". The PRS utilized a questionnaire to estimate the risk of infection, provided personalized recommendations such as testing, self-isolation, or quarantine, and featured QR code data transmission to electronic health records. The PRS served up to 2.5 million monthly users and received 67,000 backlinks from 1800 domains. We clinically evaluated the PRS at the SARS-CoV-2 testing facility at Charité and observed a 21.7% increase in patient throughput per hour and a 22.5% increase in patients per day. Patients using the PRS were twice as likely to belong to the High Risk group eligible for testing (18.6% vs. 8.9%, p < 0.0001), indicating successful compliance with CovApp's recommendations. CovApp served as a digital bridge between the population and medical staff and significantly improved testing efficiency. As an open-source platform, CovApp can be readily customized to address emerging public health crises. Further, given the EHR interface, the app is of great utility for other applications in clinical settings.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , COVID-19/epidemiologia , Registros Eletrônicos de Saúde , Teste para COVID-19 , Atenção à Saúde , Internet
9.
Stroke ; 43(2): 350-5, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22267825

RESUMO

BACKGROUND AND PURPOSE: Silent brain infarctions are associated with an increased risk of stroke in healthy individuals. Risk of recurrent stroke in patients with both symptomatic and silent brain infarction (SBI) has only been investigated in patients with cardioembolic stroke in the European Atrial Fibrillation Trial. We assessed whether patients with recent noncardioembolic stroke and SBI detected on MRI are at increased risk for recurrent stroke, other cardiovascular events, and mortality. METHODS: The prevalence of SBI detected on MRI was assessed in 1014 patients enrolled in the imaging substudy of the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial. The primary outcome was first recurrence of stroke in patients with both symptomatic stroke and SBI in comparison with age- and sex-matched patients with stroke without SBI. Secondary outcomes were a combined vascular end point, other vascular events, and mortality. The 2 groups were compared using conditional logistic regression. RESULTS: Silent brain infarction was detected in 207 (20.4%) of the 1014 patients. Twenty-seven (13.0%) patients with SBI and 19 (9.2%) without SBI had a recurrent stroke (OR, 1.42; 95% CI, 0.79-2.56; P=0.24) during a mean follow-up of 2.5 years. Similarly, there was no statistically significant difference for all secondary outcome parameters between patients with SBI and matched patients without SBI. CONCLUSIONS: The presence of SBI in patients with recent mild noncardioembolic ischemic stroke could not be shown to be an independent risk factor for recurrent stroke, other vascular events, or a higher mortality rate. CLINICAL TRIAL REGISTRATION: URL: http://clinicaltrials.gov. Unique identifier: NCT00153062.


Assuntos
Infarto Cerebral/complicações , Acidente Vascular Cerebral/prevenção & controle , Idoso , Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Aspirina/uso terapêutico , Benzimidazóis/uso terapêutico , Benzoatos/uso terapêutico , Isquemia Encefálica/complicações , Isquemia Encefálica/patologia , Infarto Cerebral/patologia , Clopidogrel , Dipiridamol/uso terapêutico , Feminino , Humanos , Embolia Intracraniana/complicações , Embolia Intracraniana/epidemiologia , Embolia Intracraniana/patologia , Estimativa de Kaplan-Meier , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Inibidores da Agregação Plaquetária/uso terapêutico , Fatores de Risco , Prevenção Secundária , Fatores Socioeconômicos , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/patologia , Telmisartan , Ticlopidina/análogos & derivados , Ticlopidina/uso terapêutico , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Vasodilatadores/uso terapêutico
10.
Stroke ; 43(9): 2336-42, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22738922

RESUMO

BACKGROUND AND PURPOSE: High blood pressure is one of the main risk factors for cerebral white matter lesions (WMLs). There is limited evidence from one randomized trial that blood pressure-lowering is able to slow WML progression. We investigated whether telmisartan prevents WML progression in the imaging substudy of the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial. METHODS: This predefined substudy comprised 771 patients (mean age, 65 years) with recent ischemic stroke of noncardioembolic origin who received telmisartan or placebo during a mean follow-up of 27.9 (SD, 7.6) months and had 2 evaluable MRI examinations after index stroke and at study closeout. All MRI scans were centrally adjudicated for progression of periventricular and subcortical WML by 2 neuroradiologists blinded to treatment allocation. RESULTS: Mean blood pressure was 3.0/1.3 mm Hg lower with telmisartan compared with placebo at follow-up MRI. There was no statistically significant difference in progression of the mean periventricular WML score (least squares mean difference, 0.14; 95% CI, -0.12 to 0.39; P=0.29) and mean subcortical WML diameter (least squares mean difference, -0.35 mm; 95% CI, -1.00 to 0.31 mm; P=0.30) during follow-up between patients on telmisartan and placebo. CONCLUSIONS: Treatment with telmisartan on top of existing antihypertensive medication did not result in significant blood pressure-lowering and did not prevent the progression of WML in patients with a recent ischemic stroke in this patient cohort. Our analysis is limited by the relatively short follow-up period. Clinical Trial Registration- URL: http://clinicaltrials.gov. Unique Identifier: NCT00153062.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Anti-Hipertensivos/uso terapêutico , Benzimidazóis/uso terapêutico , Benzoatos/uso terapêutico , Encéfalo/patologia , Acidente Vascular Cerebral/tratamento farmacológico , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Aspirina/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Progressão da Doença , Feminino , Seguimentos , Humanos , Modelos Logísticos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Inibidores da Agregação Plaquetária/uso terapêutico , Fatores de Risco , Prevenção Secundária , Acidente Vascular Cerebral/patologia , Telmisartan , Resultado do Tratamento
11.
Nature ; 441(7096): 1011-4, 2006 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-16791200

RESUMO

The accumulation of somatic DNA damage has been implicated as a cause of ageing in metazoa. One possible mechanism by which increased DNA damage could lead to cellular degeneration and death is by stochastic deregulation of gene expression. Here we directly test for increased transcriptional noise in aged tissue by dissociating single cardiomyocytes from fresh heart samples of both young and old mice, followed by global mRNA amplification and quantification of mRNA levels in a panel of housekeeping and heart-specific genes. Although gene expression levels already varied among cardiomyocytes from young heart, this heterogeneity was significantly elevated at old age. We had demonstrated previously an increased load of genome rearrangements and other mutations in the heart of aged mice. To confirm that increased stochasticity of gene expression could be a result of increased genome damage, we treated mouse embryonic fibroblasts in culture with hydrogen peroxide. Such treatment resulted in a significant increase in cell-to-cell variation in gene expression, which was found to parallel the induction and persistence of genome rearrangement mutations at a lacZ reporter locus. These results underscore the stochastic nature of the ageing process, and could provide a mechanism for age-related cellular degeneration and death in tissues of multicellular organisms.


Assuntos
Envelhecimento/genética , Expressão Gênica , Miocárdio/metabolismo , Envelhecimento/fisiologia , Animais , Coração/fisiologia , Peróxido de Hidrogênio , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miocárdio/citologia , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
12.
Eur J Pediatr ; 171(11): 1611-8, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22729243

RESUMO

UNLABELLED: Treacher Collins syndrome (TCS) is the most common and well-known mandibulofacial dysostosis caused by mutations in at least three genes involved in pre-rRNA transcription, the TCOF1, POLR1D and POLR1C genes. We present a severely affected male individual with TCS with a heterozygous de novo frameshift mutation within the TCOF1 gene (c.790_791delAG,p.Ser264GlnfsX7) and compare the clinical findings with three previously unpublished, milder affected individuals from two families with the same mutation. We elucidate typical clinical features of TCS and its clinical implications for the paediatrician and mandibulofacial surgeon, especially in severely affected individuals and give a short review of the literature. CONCLUSION: The clinical data of these three families illustrate that the phenotype associated with this specific mutation has a wide intra- and interfamilial variability, which confirms that variable expressivity in carriers of TCOF1 mutations is not a simple consequence of the mutation but might be modified by the combination of genetic, environmental and stochastic factors. Being such a highly complex disease treatment of individuals with TCS should be tailored to the specific needs of each individual, preferably by a multidisciplinary team consisting of paediatricians, craniofacial surgeons and geneticists.


Assuntos
Mutação da Fase de Leitura , Disostose Mandibulofacial/genética , Proteínas Nucleares/genética , Fosfoproteínas/genética , Criança , Feminino , Marcadores Genéticos , Humanos , Recém-Nascido , Masculino , Disostose Mandibulofacial/diagnóstico , Fenótipo
13.
Geburtshilfe Frauenheilkd ; 82(7): 747-754, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35815101

RESUMO

Introduction The gathering of health and quality-of-life issues that matter most to patients over so-called patient-reported outcomes (PROs) is a key aspect of patient-centered healthcare. In obstetrics, this approach has the potential to expand the current understanding of what quality entails by including patient perspectives. The International Consortium for Health Outcome Measures (ICHOM), founded in 2012, is a global organization which aims to standardise the collection of PROs and make the results comparable worldwide. A PRO Set for obstetrics, "Pregnancy and Childbirth", was published in 2018. The aim of our work was to translate the instruments of this set that are not yet available in German into German. Methods The instruments were translated from English into German using the Functional Assessment of Chronic Illness Therapy (FACIT) translation method. The translated instruments consisted of the Breastfeeding Self-Efficacy Scale - Short Form (BSES-SF), the Mother-to-Infant Bonding Scale (MIBS), and the Birth Satisfaction Scale - Revised (BSS-R) as well as a number of individual questions (items). Results The final version of the German translations were found to be easily comprehensible by the target group. During the cognitive debriefing, it became clear that pregnant women and women who had just given birth often used a number of medically incorrect terms to refer to their symptoms or complaints. In the translations great care was taken to ensure that the wording was as close as possible to the general usage of the language while at the same time the terminology was medically correct. To achieve a precise but comprehensible translation, the response structure of the BSES-SF also had to be adapted. Conclusions The instruments of the ICHOM Standard Set "Pregnancy and Childbirth", which were not previously available in German, were successfully translated into German. This meant dealing with a few challenges such as adapting questions or response structures. The cultural and linguistic comprehensibility of the German translations were confirmed during the subsequent cognitive debriefing. The translations offer the possibility of implementing the complete ICHOM Set for Pregnancy and Childbirth. This would provide an opportunity to expand the existing understanding of quality by including the subjective experience of women during and after childbirth and, in future, to compare outcomes with those of other hospitals across the world.

14.
ACS Appl Mater Interfaces ; 14(7): 9676-9684, 2022 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-35134299

RESUMO

Copper indium disulfide (CuInS2) grown under Cu-rich conditions exhibits high optical quality but suffers predominantly from charge carrier interface recombination, resulting in poor solar cell performance. An unfavorable "cliff"-like conduction band alignment at the buffer/CuInS2 interface could be a possible cause of enhanced interface recombination in the device. In this work, we exploit direct and inverse photoelectron spectroscopy together with electrical characterization to investigate the cause of interface recombination in chemical bath-deposited Zn(O,S)/co-evaporated CuInS2-based devices. Temperature-dependent current-voltage analyses indeed reveal an activation energy of the dominant charge carrier recombination path, considerably smaller than the absorber bulk band gap, confirming the dominant recombination channel to be present at the Zn(O,S)/CuInS2 interface. However, photoelectron spectroscopy measurements indicate a small (0.1 eV) "spike"-like conduction band offset at the Zn(O,S)/CuInS2 interface, excluding an unfavorable energy-level alignment to be the prominent cause for strong interface recombination. The observed band bending upon interface formation also suggests Fermi-level pinning not to be the main reason, leaving near-interface defects (as recently observed in Cu-rich CuInSe2) as the likely reason for the performance-limiting interface recombination.

15.
RSC Adv ; 12(13): 7996-8002, 2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35424741

RESUMO

Combinatorial material science crucially depends on robust, high-throughput characterization methods. While X-ray photoelectron spectroscopy (XPS) may provide detailed information about chemical and electronic properties, it is a time-consuming technique and, therefore, is not viewed as a high-throughput method. Here we present preliminary XPS data of 169 measurement spots on a combinatorial 72 × 72 cm2 Cu x Ni1-x O y compositional library to explore how characterization and evaluation routines can be optimized to improve throughput in XPS for combinatorial studies. In particular, two quantification approaches are compared. We find that a simple integration (of XPS peak regions) approach is suited for fast evaluation of, in the example system, the [Cu]/([Cu] + [Ni]) ratio. Complementary to that, the time-consuming (XPS peak-) fit approach provides additional insights into chemical speciation and oxidation state changes, without a large deviation of the [Cu]/([Cu] + [Ni]) ratio. This insight suggests exploiting the fast integration approach for 'real time' analysis during XPS data collection, paving the way for an 'on-the-fly' selection of points of interest (i.e., areas on the sample where sudden composition changes have been identified) for detailed XPS characterization. Together with the envisioned improvements when going from laboratory to synchrotron-based excitation sources, this will shorten the analysis time sufficiently for XPS to become a realistic characterization option for combinatorial material science.

16.
Protein Expr Purif ; 79(2): 187-90, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21664273

RESUMO

The Escherichia coli unc-operon encodes the genes for the subunits of the F0F1-ATP synthase and an integral membrane protein of unknown function called UncI. UncI influences the cell-growth and activity of F0F1, but its exact function is still unknown. The expression level is too low to extract milligram amounts of UncI from E. coli membranes and the existing purification protocol based on methanol/chloroform is not suitable for structural and functional studies. Here we present protocols to increase the expression level, to purify UncI in a detergent where UncI is monodisperse, and we characterize its oligomeric state.


Assuntos
Proteínas de Bactérias/isolamento & purificação , Escherichia coli/genética , Proteínas de Membrana/isolamento & purificação , Óperon/genética , Proteínas Recombinantes/isolamento & purificação , Complexos de ATP Sintetase/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Cromatografia em Gel , Clonagem Molecular , Primers do DNA/química , Primers do DNA/genética , Escherichia coli/metabolismo , Expressão Gênica , Proteínas de Membrana/química , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Plasmídeos , Polimerização , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transformação Bacteriana
17.
ACS Appl Mater Interfaces ; 12(10): 12353-12361, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32045207

RESUMO

We report on the chemical and electronic structure of cesium tin bromide (CsSnBr3) and how it is impacted by the addition of 20 mol % tin fluoride (SnF2) to the precursor solution, using both surface-sensitive lab-based soft X-ray photoelectron spectroscopy (XPS) and near-surface bulk-sensitive synchrotron-based hard XPS (HAXPES). To determine the reproducibility and reliability of conclusions, several (nominally identically prepared) sample sets were investigated. The effects of deposition reproducibility, handling, and transport are found to cause significant changes in the measured properties of the films. Variations in the HAXPES-derived compositions between individual sample sets were observed, but in general, they confirm that the addition of 20 mol % SnF2 improves coverage of the titanium dioxide substrate by CsSnBr3 and decreases the oxidation of SnII to SnIV while also suppressing formation of secondary Br and Cs species. Furthermore, the (surface) composition is found to be Cs-deficient and Sn-rich compared to the nominal stoichiometry. The valence band (VB) shows a SnF2-induced redistribution of Sn 5s-derived density of states, reflecting the changing SnII/SnIV ratio. Notwithstanding some variability in the data, we conclude that SnF2 addition decreases the energy difference between the VB maximum of CsSnBr3 and the Fermi level, which we explain by defect chemistry considerations.

18.
ACS Appl Mater Interfaces ; 12(31): 34941-34948, 2020 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-32633119

RESUMO

The underlying beneficial mechanism of heavy alkali postdeposition treatment (PDT) of Cu(In,Ga)Se2 thin-film solar cell absorbers that led to new record efficiencies in recent years is studied using photoelectron spectroscopy. Excitation energies between 40.8 eV and 6 keV were used to examine the near-surface region of Cu(In,Ga)Se2 thin-film solar cell absorbers that underwent NaF and combined NaF/RbF PDT. The already Cu-deficient surface region after NaF PDT, which is modeled as a Cu:(In + Ga):Se = 1:5:8 phase, shows further depletion after NaF/RbF PDT and seems to incorporate some Rb. Additionally, we have found strong indications for the NaF/RbF PDT-induced formation of a Rb-In-Se-type compound with a 1:1:2 stoichiometry partially covering the absorber surface. The electronic Cu(In,Ga)Se2 structure is modified due to the RbF treatment, with a pronounced shift in the valence band maximum away from the Fermi level in the immediate vicinity of the surface.

19.
Clin Microbiol Infect ; 26(12): 1685.e7-1685.e12, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32827715

RESUMO

OBJECTIVE: In Berlin, the first public severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing site started 1 day after the first case in the city occurred. We describe epidemiological and clinical characteristics and aim at identifying risk factors for SARS-CoV-2 detection during the first 6 weeks of operation. METHODS: Testing followed national recommendations, but was also based on the physician's discretion. We related patient characteristics to SARS-CoV-2 test positivity for exploratory analyses using a cross-sectional, observational study design. RESULTS: Between 3 March and 13 April 2020, 5179 individuals attended the site (median age 34 years; interquartile range 26-47 years). The median time since disease onset was 4 days (interquartile range 2-7 days). Among 4333 persons tested, 333 (7.7%) were positive. Test positivity increased up to 10.3% (96/929) during the first 3 weeks and then declined, paralleling Germany's lock-down and the course of the epidemic in Berlin. Strict adherence to testing guidelines resulted in 10.4% (262/2530) test positivity, compared with 3.9% (71/1803) among individuals tested for other indications. A nightclub was a transmission hotspot; 27.7% (26/94) of one night's visitors were found positive. Smell and/or taste dysfunction indicated coronavirus disease 2019 (COVID-19) with 85.6% specificity (95% CI 82.1%-88.1%). Four per cent (14/333) of those infected were asymptomatic. Risk factors for detection of SARS-CoV-2 infection were recent contact with a positive case (second week after contact, OR 3.42; 95% CI 2.48-4.71), travel to regions of high pandemic activity (e.g. Austria, OR 4.16; 95% CI 2.48-6.99), recent onset of symptoms (second week, OR 3.61; 95% CI 1.87-6.98) and an impaired sense of smell/taste (4.08; 95% CI 2.36-7.03). CONCLUSIONS: In this young population, early-onset presentation of COVID-19 resembled flu-like symptoms, except for smell and/or taste dysfunction. Risk factors for SARS-CoV-2 detection were return from regions with high incidence and contact with confirmed SARS-CoV-2 cases, particularly when tests were administered within the first 2 weeks after contact and/or onset of symptoms.


Assuntos
Teste para COVID-19/estatística & dados numéricos , COVID-19/epidemiologia , Portador Sadio/epidemiologia , Adulto , Berlim/epidemiologia , COVID-19/diagnóstico , COVID-19/fisiopatologia , Teste para COVID-19/métodos , Portador Sadio/diagnóstico , Portador Sadio/virologia , Estudos Transversais , Feminino , Humanos , Incidência , Masculino , Programas de Rastreamento/estatística & dados numéricos , Pessoa de Meia-Idade , Transtornos do Olfato/epidemiologia , Transtornos do Olfato/virologia , Pandemias/estatística & dados numéricos , Fatores de Risco , Sensibilidade e Especificidade , Distúrbios do Paladar/epidemiologia , Distúrbios do Paladar/virologia
20.
Mol Biochem Parasitol ; 163(1): 61-5, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18840477

RESUMO

In eukaryotes, proteins containing RNA Recognition Motifs (RRMs) are involved in many different RNA processing reactions, RNA transport, and mRNA decay. Kinetoplastids rely extensively on post-transcriptional mechanisms to control gene expression, so RRM domain proteins are expected to play a prominent role. We here describe the results of an RNA interference screen targeting 37 of the 72 RRM-domain proteins of Trypanosoma brucei. RNAi targeting 8 of the genes caused clear growth inhibition in bloodstream trypanosomes, and milder effects were seen for 9 more genes. The small, single-RRM protein TbRBP3 specifically associated with 10 mRNAs in trypanosome lysates, but RBP3 depletion did not affect the transcriptome.


Assuntos
Proteínas de Protozoários/metabolismo , Interferência de RNA , Proteínas de Ligação a RNA/metabolismo , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/metabolismo , Animais , Humanos , Estrutura Terciária de Proteína , Transporte Proteico , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , RNA de Protozoário/genética , RNA de Protozoário/metabolismo , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Trypanosoma brucei brucei/química , Tripanossomíase Africana/parasitologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA