Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 22
Filter
1.
Unfallchirurgie (Heidelb) ; 127(4): 305-312, 2024 Apr.
Article in German | MEDLINE | ID: mdl-37880352

ABSTRACT

BACKGROUND: Both in Germany and internationally there is a vehement controversy about the appropriate time for care of proximal femoral fractures in older patients. The effort to achieve high quality and uniform standards of care culminated in the German healthcare system in the strict requirement of delay-free surgery within 24 h. Until now, in view of their high vulnerability patients who were severely injured were too often operated on late with the reference to a general medical condition that could be improved preoperatively. In particular, the fear of complications due to a pre-existing long-term anticoagulation treatment was repeatedly emphasized. OBJECTIVE: The present study is dedicated to the question of whether a delay in surgery of anticoagulated patients with proximal femoral fractures already during the inpatient course has a detrimental effect on the complication statistics and the mortality of the patients. The extent to which external quality assurance data are suitable for rebutting any objections to an operation as soon as possible are examined. MATERIAL AND METHODS: The study is based on treatment data from the external inpatient quality assurance procedure of the federal state of North Rhine-Westphalia from the years 2018-2020. Patients with a proximal femoral fracture were considered. This includes femoral neck fractures and fractures in the area of the pertrochanteric to subtrochanteric region. Only cases with joint-preserving fracture care were selected. The data sets were analyzed using suitable statistical software. RESULTS: More general complications and deaths have been observed in anticoagulated patients. The trend of delayed fracture treatment under anticoagulant medication continues to be clearly visible. A positive association between longer preoperative waiting time and undesirable courses can be confirmed. CONCLUSION: With respect to fracture care when taking anticoagulants, it must be critically examined to what extent a rapid normalization of the coagulation situation is necessary and this actually improves the chances of low complication courses. Should the elimination of the anticoagulant effect by substitution or antidote appear necessary, this should not prevent early care.


Subject(s)
Femoral Neck Fractures , Proximal Femoral Fractures , Humans , Aged , Femoral Neck Fractures/etiology , Fracture Fixation, Internal/adverse effects , Long-Term Care , Anticoagulants/therapeutic use
2.
Lancet ; 400(10357): 997-1007, 2022 09 24.
Article in English | MEDLINE | ID: mdl-36063821

ABSTRACT

BACKGROUND: Asundexian (Bayer AG, Leverkusen, Germany), an oral small molecule factor XIa (FXIa) inhibitor, might prevent thrombosis without increasing bleeding. Asundexian's effect for secondary prevention of recurrent stroke is unknown. METHODS: In this randomised, double-blind, placebo-controlled, phase 2b dose-finding trial (PACIFIC-Stroke), patients with acute (within 48 h) non-cardioembolic ischaemic stroke were recruited from 196 hospitals in 23 countries. Patients were eligible if they were aged 45 years or older, to be treated with antiplatelet therapy, and able to have a baseline MRI (either before or within 72 h of randomisation). Eligible participants were randomly assigned (1:1:1:1), using an interactive web-based response system and stratified according to anticipated antiplatelet therapy (single vs dual), to once daily oral asundexian (BAY 2433334) 10 mg, 20 mg, or 50 mg, or placebo in addition to usual antiplatelet therapy, and were followed up during treatment for 26-52 weeks. Brain MRIs were obtained at study entry and at 26 weeks or as soon as possible after treatment discontinuation. The primary efficacy outcome was the dose-response effect on the composite of incident MRI-detected covert brain infarcts and recurrent symptomatic ischaemic stroke at or before 26 weeks after randomisation. The primary safety outcome was major or clinically relevant non-major bleeding as defined by International Society on Thrombosis and Haemostasis criteria. The efficacy outcome was assessed in all participants assigned to treatment, and the safety outcome was assessed in all participants who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT04304508, and is now complete. FINDINGS: Between June 15, 2020, and July 22, 2021, 1880 patients were screened and 1808 participants were randomly assigned to asundexian 10 mg (n=455), 20 mg (n=450), or 50 mg (n=447), or placebo (n=456). Mean age was 67 years (SD 10) and 615 (34%) participants were women, 1193 (66%) were men, 1505 (83%) were White, and 268 (15%) were Asian. The mean time from index stroke to randomisation was 36 h (SD 10) and median baseline National Institutes of Health Stroke Scale score was 2·0 (IQR 1·0-4·0). 783 (43%) participants received dual antiplatelet treatment for a mean duration of 70·1 days (SD 113·4) after randomisation. At 26 weeks, the primary efficacy outcome was observed in 87 (19%) of 456 participants in the placebo group versus 86 (19%) of 455 in the asundexian 10 mg group (crude incidence ratio 0·99 [90% CI 0·79-1·24]), 99 (22%) of 450 in the asundexian 20 mg group (1·15 [0·93-1·43]), and 90 (20%) of 447 in the asundexian 50 mg group (1·06 [0·85-1·32]; t statistic -0·68; p=0·80). The primary safety outcome was observed in 11 (2%) of 452 participants in the placebo group versus 19 (4%) of 445 in the asundexian 10 mg group, 14 (3%) of 446 in the asundexian 20 mg group, and 19 (4%) of 443 in the asundexian 50 mg group (all asundexian doses pooled vs placebo hazard ratio 1·57 [90% CI 0·91-2·71]). INTERPRETATION: In this phase 2b trial, FXIa inhibition with asundexian did not reduce the composite of covert brain infarction or ischaemic stroke and did not increase the composite of major or clinically relevant non-major bleeding compared with placebo in patients with acute, non-cardioembolic ischaemic stroke. FUNDING: Bayer AG.


Subject(s)
Brain Ischemia , Ischemic Stroke , Stroke , Thrombosis , Aged , Anticoagulants/therapeutic use , Brain Ischemia/drug therapy , Brain Ischemia/prevention & control , Double-Blind Method , Factor XIa , Female , Hemorrhage/chemically induced , Hemorrhage/drug therapy , Humans , Male , Platelet Aggregation Inhibitors/therapeutic use , Stroke/drug therapy , Stroke/prevention & control , Treatment Outcome
3.
Lancet ; 399(10333): 1383-1390, 2022 04 09.
Article in English | MEDLINE | ID: mdl-35385695

ABSTRACT

BACKGROUND: Direct-acting oral anticoagulant use for stroke prevention in atrial fibrillation is limited by bleeding concerns. Asundexian, a novel, oral small molecule activated coagulation factor XIa (FXIa) inhibitor, might reduce thrombosis with minimal effect on haemostasis. We aimed to determine the optimal dose of asundexian and to compare the incidence of bleeding with that of apixaban in patients with atrial fibrillation. METHODS: In this randomised, double-blind, phase 2 dose-finding study, we compared asundexian 20 mg or 50 mg once daily with apixaban 5 mg twice daily in patients aged 45 years or older with atrial fibrillation, a CHA2DS2-VASc score of at least 2 if male or at least 3 if female, and increased bleeding risk. The study was conducted at 93 sites in 14 countries, including 12 European countries, Canada, and Japan. Participants were randomly assigned (1:1:1) to a treatment group using an interactive web response system, with randomisation stratified by whether patients were receiving a direct-acting oral anticoagulant before the study start. Masking was achieved using a double-dummy design, with participants receiving both the assigned treatment and a placebo that resembled the non-assigned treatment. The primary endpoint was the composite of major or clinically relevant non-major bleeding according to International Society on Thrombosis and Haemostasis criteria, assessed in all patients who took at least one dose of study medication. This trial is registered with ClinicalTrials.gov, NCT04218266, and EudraCT, 2019-002365-35. FINDINGS: Between Jan 30, 2020, and June 21, 2021, 862 patients were enrolled. 755 patients were randomly assigned to treatment. Two patients (assigned to asundexian 20 mg) never took any study medication, resulting in 753 patients being included in the analysis (249 received asundexian 20 mg, 254 received asundexian 50 g, and 250 received apixaban). The mean age of participants was 73·7 years (SD 8·3), 309 (41%) were women, 216 (29%) had chronic kidney disease, and mean CHA2DS2-VASc score was 3·9 (1·3). Asundexian 20 mg resulted in 81% inhibition of FXIa activity at trough concentrations and 90% inhibition at peak concentrations; asundexian 50 mg resulted in 92% inhibition at trough concentrations and 94% inhibition at peak concentrations. Ratios of incidence proportions for the primary endpoint were 0·50 (90% CI 0·14-1·68) for asundexian 20 mg (three events), 0·16 (0·01-0·99) for asundexian 50 mg (one event), and 0·33 (0·09-0·97) for pooled asundexian (four events) versus apixaban (six events). The rate of any adverse event occurring was similar in the three treatment groups: 118 (47%) with asundexian 20 mg, 120 (47%) with asundexian 50 mg, and 122 (49%) with apixaban. INTERPRETATION: The FXIa inhibitor asundexian at doses of 20 mg and 50 mg once daily resulted in lower rates of bleeding compared with standard dosing of apixaban, with near-complete in-vivo FXIa inhibition, in patients with atrial fibrillation. FUNDING: Bayer.


Subject(s)
Anticoagulants , Atrial Fibrillation , Factor Xa Inhibitors , Aged , Anticoagulants/adverse effects , Atrial Fibrillation/drug therapy , Double-Blind Method , Factor Xa Inhibitors/adverse effects , Female , Hemorrhage/chemically induced , Humans , Male , Pyrazoles/adverse effects , Pyridones/adverse effects , Treatment Outcome
4.
Eur Heart J Cardiovasc Pharmacother ; 8(8): 786-795, 2022 12 02.
Article in English | MEDLINE | ID: mdl-35383832

ABSTRACT

AIMS: To describe outcomes of patients with chronic coronary artery disease (CAD) and/or peripheral artery disease (PAD) enrolled in the Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) randomized trial who were treated with the combination of rivaroxaban 2.5 mg twice daily and aspirin 100 mg once daily during long-term open-label extension (LTOLE). METHODS AND RESULTS: Of the 27 395 patients enrolled in COMPASS, 12 964 (mean age at baseline 67.2 years) from 455 sites in 32 countries were enrolled in LTOLE and treated with the combination of rivaroxaban and aspirin for a median of 374 additional days (range 1-1191 days). During LTOLE, the incident events per 100 patient years were as follows: for the primary outcome [cardiovascular death, stroke, or myocardial infarction (MI)] 2.35 [95% confidence interval (CI) 2.11-2.61], mortality 1.87 (1.65-2.10), stroke 0.62 (0.50-0.76), and MI 1.02 (0.86-1.19), with CIs that overlapped those seen during the randomized treatment phase with the combination of rivaroxaban and aspirin. The incidence rates for major and minor bleeding were 1.01 (0.86-1.19) and 2.49 (2.24-2.75), compared with 1.67 (1.48-1.87) and 5.11 (95% CI 4.77-5.47), respectively, during the randomized treatment phase with the combination. CONCLUSION: In patients with chronic CAD and/or PAD, extended combination treatment for a median of 1 year and a maximum of 3 years was associated with incidence rates for efficacy and bleeding that were similar to or lower than those seen during the randomized treatment phase, without any new safety signals.


Subject(s)
Myocardial Infarction , Peripheral Arterial Disease , Stroke , Humans , Infant , Aspirin , Drug Therapy, Combination , Myocardial Infarction/epidemiology , Peripheral Arterial Disease/diagnosis , Peripheral Arterial Disease/drug therapy , Peripheral Arterial Disease/epidemiology , Rivaroxaban , Stroke/epidemiology
5.
BMC Public Health ; 21(1): 1944, 2021 10 27.
Article in English | MEDLINE | ID: mdl-34702221

ABSTRACT

We read with interest the article entitled "The global distribution of acute unintentional pesticide poisoning: estimations based on a systematic review". We wholeheartedly agree that it is important to evaluate the extent of this issue. We would like to understand the numbers provided in this article, which appear to overestimate the global burden of pesticide poisonings. We also feel that addressing the benefits of these chemistries is important for a complete evaluation.


Subject(s)
Pesticides , Humans
6.
J. Am. Coll. Cardiol ; 73(25): 3271-3280, Jul. 2019. gráfico, tabela
Article in English | Sec. Est. Saúde SP, SESSP-IDPCPROD, Sec. Est. Saúde SP | ID: biblio-1024371

ABSTRACT

BACKGROUND: The COMPASS (Cardiovascular Outcomes for People Using Anticoagulation Strategies) trial showed that the combination of low-dose rivaroxaban and aspirin reduced major vascular events in patients with stable vascular disease. OBJECTIVES: The purpose of this study was to identify subsets of patients at higher risk of recurrent vascular events, which may help focus the use of rivaroxaban and aspirin therapy. METHODS: COMPASS patients with vascular disease were risk stratified using 2 methods: the REACH (reduction of Atherothrombosis for Continued Health) atherothrombosis risk score and CART (Classification and Regression Tree) analysis. The absolute risk differences for rivaroxaban with aspirin were compared to aspirin alone over 30 months for the composite of cardiovascular death, myocardial infarction, stroke, acute limb ischemia, or vascular amputation; for severe bleeding; and for the net clinical benefit. RESULTS: High-risk patients using the REACH score were those with 2 or more vascular beds affected, history of heart failure (HF), or renal insufficiency, and by CART analysis were those with ≥2 vascular beds affected, history of HF, or diabetes. Rivaroxaban and aspirin combination reduced the serious vascular event incidence by 25% (4.48% vs. 5.95%, hazard ratio: 0.75; 95% confidence interval: 0.66 to 0.85), equivalent to 23 events prevented per 1,000 patients treated for 30 months, at the cost of a nonsignificant 34% increase in severe bleeding (1.34; 95% confidence interval: 0.95 to 1.88), or 2 events caused per 1,000 patients treated. Among patients with ≥1 high-risk feature identified from the CART analysis, rivaroxaban and aspirin prevented 33 serious vascular events, whereas in lower-risk patients, rivaroxaban and aspirin treatment led to the avoidance of 10 events per 1,000 patients treated for 30 months. CONCLUSIONS: In patients with vascular disease, further risk stratification can identify higher-risk patients (≥2 vascular beds affected, HF, renal insufficiency, or diabetes). The net clinical benefit remains favorable for most patients treated with rivaroxaban and aspirin compared with aspirin. (AU)


Subject(s)
Vascular Diseases/drug therapy , Aspirin , Anticoagulants
7.
J Am Coll Cardiol ; 73(25): 3271-3280, 2019 07 02.
Article in English | MEDLINE | ID: mdl-31248548

ABSTRACT

BACKGROUND: The COMPASS (Cardiovascular Outcomes for People Using Anticoagulation Strategies) trial showed that the combination of low-dose rivaroxaban and aspirin reduced major vascular events in patients with stable vascular disease. OBJECTIVES: The purpose of this study was to identify subsets of patients at higher risk of recurrent vascular events, which may help focus the use of rivaroxaban and aspirin therapy. METHODS: COMPASS patients with vascular disease were risk stratified using 2 methods: the REACH (REduction of Atherothrombosis for Continued Health) atherothrombosis risk score and CART (Classification and Regression Tree) analysis. The absolute risk differences for rivaroxaban with aspirin were compared to aspirin alone over 30 months for the composite of cardiovascular death, myocardial infarction, stroke, acute limb ischemia, or vascular amputation; for severe bleeding; and for the net clinical benefit. RESULTS: High-risk patients using the REACH score were those with 2 or more vascular beds affected, history of heart failure (HF), or renal insufficiency, and by CART analysis were those with ≥2 vascular beds affected, history of HF, or diabetes. Rivaroxaban and aspirin combination reduced the serious vascular event incidence by 25% (4.48% vs. 5.95%, hazard ratio: 0.75; 95% confidence interval: 0.66 to 0.85), equivalent to 23 events prevented per 1,000 patients treated for 30 months, at the cost of a nonsignificant 34% increase in severe bleeding (1.34; 95% confidence interval: 0.95 to 1.88), or 2 events caused per 1,000 patients treated. Among patients with ≥1 high-risk feature identified from the CART analysis, rivaroxaban and aspirin prevented 33 serious vascular events, whereas in lower-risk patients, rivaroxaban and aspirin treatment led to the avoidance of 10 events per 1,000 patients treated for 30 months. CONCLUSIONS: In patients with vascular disease, further risk stratification can identify higher-risk patients (≥2 vascular beds affected, HF, renal insufficiency, or diabetes). The net clinical benefit remains favorable for most patients treated with rivaroxaban and aspirin compared with aspirin.


Subject(s)
Aspirin/therapeutic use , Cardiovascular Diseases/prevention & control , Factor Xa Inhibitors/therapeutic use , Fibrinolytic Agents/therapeutic use , Rivaroxaban/therapeutic use , Aged , Drug Therapy, Combination , Female , Humans , Male , Middle Aged , Risk Assessment
8.
Eur Radiol ; 29(11): 5873-5878, 2019 Nov.
Article in English | MEDLINE | ID: mdl-30915558

ABSTRACT

OBJECTIVES: In the German National Cohort (GNC), 30,000 individuals are examined with whole-body MRI (wbMRI), of which about 3000 participants are expected to receive an incidental finding (IF) disclosure. In order to get feedback from participants and to evaluate the IF-management procedure of the wbMRI substudy, a follow-up questionnaire was developed. This single-center pilot trial was aimed to get a first impression on feasibility reproducibility and validity of such a survey in order to take necessary adjustments before initiating the survey among several thousand participants. METHODS: The questionnaires were sent out in test-retest manner to 86 participants who received a wbMRI examination in January-February 2016 at the imaging center in Neubrandenburg. The ratio of participants with and without IF notification was 1:1. Descriptive statistics was performed. RESULTS: A first response of 94% and completion proportion of 99% were achieved. Participants were satisfied with the examination procedure. Ninety-five percent of participants considered it very important to receive notification of IFs. Participants reported minimal stress levels while waiting for a possible IF notification letter, but high stress levels when an IF letter was received. Phrasing of the IF reports was rated in 97% as well understandable and in 55% as beneficial to health status. CONCLUSIONS: This questionnaire will serve researchers within the GNC as a fundamental instrument not only for quality management analyses but also for the investigation of still unacknowledged scientific and ethical questions contributing to evidence-based guidelines concerning the complex approach to IFs in future population-based imaging. KEY POINTS: • Evidence-based guidelines for reporting incidental findings in population whole-body MRI are lacking. • Pilot-testing of a questionnaire for the evaluation of practical and ethical aspects of the procedure to report incidental findings in the German National Cohort shows a high level of acceptance and high return rate by participants. • Participants reported minimal stress levels while waiting for a possible incidental finding notification letter, which increased significantly, when such a letter was received.


Subject(s)
Incidental Findings , Magnetic Resonance Imaging/methods , Whole Body Imaging/methods , Feasibility Studies , Female , Follow-Up Studies , Germany , Humans , Male , Middle Aged , Pilot Projects , Reproducibility of Results , Surveys and Questionnaires
9.
J Orthop Surg Res ; 13(1): 108, 2018 May 09.
Article in English | MEDLINE | ID: mdl-29739435

ABSTRACT

BACKGROUND: Iliac crest bone harvesting is a frequently performed surgical procedure widely used to treat bone defects. The objective of this study is to assess the biomechanical quantities related to risk for pelvic fracture after harvesting an autologous bone graft at the anterior iliac crest. METHODS: Finite element models with a simulated harvest site (sized 15 × 20 mm, 15 × 35 mm, 30 × 20 mm and 30 × 35 mm) in the iliac wing are created. The relevant loading case is when the ipsilateral leg is lifted off the ground. Musculoskeletal analysis is utilized to compute the muscle and joint forces involved in this motion. These forces are used as boundary conditions for the finite element analyses. Bone tissue stress is analyzed. RESULTS: Critical stress peaks are located between the anterior superior iliac spine (ASIS) and the anterior edge of the harvest site. Irrespective of the graft size, the iliac wing does not show any significant stress peaks with the harvest site being 20 to 25 mm posterior to the ASIS. The harvest area itself inhibits the distribution of the forces applied on the ASIS to extend to the posterior iliac wing. This leads to a lack of stress posterior to the harvest site. A balanced stress distribution with no stress peaks appears when the bone graft is taken below the iliac crest. CONCLUSION: A harvest site located at least 20 to 25 mm posterior to the ASIS should be preferred to minimize the risk of iliac fatigue fracture.


Subject(s)
Cancellous Bone/surgery , Cortical Bone/surgery , Fractures, Stress/prevention & control , Ilium/surgery , Tissue and Organ Harvesting/methods , Weight-Bearing , Biomechanical Phenomena/physiology , Bone Transplantation/adverse effects , Bone Transplantation/methods , Cancellous Bone/diagnostic imaging , Cancellous Bone/transplantation , Cortical Bone/diagnostic imaging , Cortical Bone/transplantation , Fractures, Stress/diagnostic imaging , Fractures, Stress/etiology , Humans , Ilium/diagnostic imaging , Ilium/physiology , Tissue and Organ Harvesting/adverse effects , Weight-Bearing/physiology
10.
Nano Lett ; 18(3): 1707-1713, 2018 03 14.
Article in English | MEDLINE | ID: mdl-29425440

ABSTRACT

There are a number of theoretical proposals based on strain engineering of graphene and other two-dimensional materials, however purely mechanical control of strain fields in these systems has remained a major challenge. The two approaches mostly used so far either couple the electrical and mechanical properties of the system simultaneously or introduce some unwanted disturbances due to the substrate. Here, we report on silicon micromachined comb-drive actuators to controllably and reproducibly induce strain in a suspended graphene sheet in an entirely mechanical way. We use spatially resolved confocal Raman spectroscopy to quantify the induced strain, and we show that different strain fields can be obtained by engineering the clamping geometry, including tunable strain gradients of up to 1.4%/µm. Our approach also allows for multiple axis straining and is equally applicable to other two-dimensional materials, opening the door to investigating their mechanical and electromechanical properties. Our measurements also clearly identify defects at the edges of a graphene sheet as being weak spots responsible for its mechanical failure.

15.
ACS Appl Mater Interfaces ; 8(14): 9377-83, 2016 Apr 13.
Article in English | MEDLINE | ID: mdl-26986938

ABSTRACT

We present a method to create and erase spatially resolved doping profiles in graphene-hexagonal boron nitride heterostructures. The technique is based on photoinduced doping by a focused laser beam and does neither require masks nor photoresists. This makes our technique interesting for rapid prototyping of unconventional electronic device schemes, where the spatial resolution of the rewritable, long-term stable doping profiles is limited by only the laser spot size (≈600 nm) and the accuracy of sample positioning. Our optical doping method offers a way to implement and to test different, complex doping patterns in one and the very same graphene device, which is not achievable with conventional gating techniques.

16.
Nano Lett ; 15(3): 1547-52, 2015 Mar 11.
Article in English | MEDLINE | ID: mdl-25646665

ABSTRACT

Many-body effects resulting from strong electron-electron and electron-phonon interactions play a significant role in graphene physics. We report on their manifestation in low B field magneto-phonon resonances in high-quality exfoliated single-layer and bilayer graphene encapsulated in hexagonal boron nitride. These resonances allow us to extract characteristic effective Fermi velocities, as high as 1.20 × 10(6) m/s, for the observed "dressed" Landau level transitions, as well as the broadening of the resonances, which increases with the Landau level index.

17.
Appl Environ Microbiol ; 80(20): 6539-48, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25128338

ABSTRACT

The application of whole cells as biocatalysts is often limited by the toxicity of organic solvents, which constitute interesting substrates/products or can be used as a second phase for in situ product removal and as tools to control multistep biocatalysis. Solvent-tolerant bacteria, especially Pseudomonas strains, are proposed as promising hosts to overcome such limitations due to their inherent solvent tolerance mechanisms. However, potential industrial applications suffer from tedious, unproductive adaptation processes, phenotypic variability, and instable solvent-tolerant phenotypes. In this study, genes described to be involved in solvent tolerance were identified in Pseudomonas taiwanensis VLB120, and adaptive solvent tolerance was proven by cultivation in the presence of 1% (vol/vol) toluene. Deletion of ttgV, coding for the specific transcriptional repressor of solvent efflux pump TtgGHI gene expression, led to constitutively solvent-tolerant mutants of P. taiwanensis VLB120 and VLB120ΔC. Interestingly, the increased amount of solvent efflux pumps enhanced not only growth in the presence of toluene and styrene but also the biocatalytic performance in terms of stereospecific styrene epoxidation, although proton-driven solvent efflux is expected to compete with the styrene monooxygenase for metabolic energy. Compared to that of the P. taiwanensis VLB120ΔC parent strain, the maximum specific epoxidation activity of P. taiwanensis VLB120ΔCΔttgV doubled to 67 U/g of cells (dry weight). This study shows that solvent tolerance mechanisms, e.g., the solvent efflux pump TtgGHI, not only allow for growth in the presence of organic compounds but can also be used as tools to improve redox biocatalysis involving organic solvents.


Subject(s)
Genetic Engineering/methods , Pseudomonas/genetics , Pseudomonas/metabolism , Styrene/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Biocatalysis , Drug Resistance, Bacterial , Epoxy Compounds/metabolism , Epoxy Compounds/pharmacology , Gene Deletion , Molecular Sequence Data , Pseudomonas/drug effects , Solvents/pharmacology , Styrene/pharmacology
18.
Biom J ; 56(6): 1076-92, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25123830

ABSTRACT

Case-parent trio studies considering genotype data from children affected by a disease and their parents are frequently used to detect single nucleotide polymorphisms (SNPs) associated with disease. The most popular statistical tests for this study design are transmission/disequilibrium tests (TDTs). Several types of these tests have been developed, for example, procedures based on alleles or genotypes. Therefore, it is of great interest to examine which of these tests have the highest statistical power to detect SNPs associated with disease. Comparisons of the allelic and the genotypic TDT for individual SNPs have so far been conducted based on simulation studies, since the test statistic of the genotypic TDT was determined numerically. Recently, however, it has been shown that this test statistic can be presented in closed form. In this article, we employ this analytic solution to derive equations for calculating the statistical power and the required sample size for different types of the genotypic TDT. The power of this test is then compared with the one of the corresponding score test assuming the same mode of inheritance as well as the allelic TDT based on a multiplicative mode of inheritance, which is equivalent to the score test assuming an additive mode of inheritance. This is, thus, the first time the power of these tests are compared based on equations, yielding instant results and omitting the need for time-consuming simulation studies. This comparison reveals that these tests have almost the same power, with the score test being slightly more powerful.


Subject(s)
Biometry/methods , Genotype , Parents , Sample Size , Child , Gene Frequency , Humans , Linkage Disequilibrium , Polymorphism, Single Nucleotide , Regression Analysis
19.
Genet Epidemiol ; 38(6): 516-22, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25048299

ABSTRACT

Case-parent trio studies are commonly employed in genetics to detect variants underlying common complex disease risk. Both commercial and freely available software suites for genetic data analysis usually contain methods for case-parent trio designs. A user might, however, experience limitations with these packages, which can include missing functionality to extend the software if a desired analysis has not been implemented, and the inability to programmatically capture all the software versions used for low-level processing and high-level inference of genomic data, a critical consideration in particular for high-throughput experiments. Here, we present a software vignette (i.e., a manual with step by step instructions and examples to demonstrate software functionality) for reproducible genome-wide analyses of case-parent trio data using the open source Bioconductor package trio. The workflow for the practitioner uses data from previous genetic trio studies to illustrate functions for marginal association tests, assessment of parent-of-origin effects, power and sample size calculations, and functions to detect gene-gene and gene-environment interactions associated with disease.


Subject(s)
Genetic Variation , Software , Child , Gene-Environment Interaction , Genetic Association Studies , Genotype , Humans , Parents , Polymorphism, Single Nucleotide
20.
Nat Commun ; 4: 1753, 2013.
Article in English | MEDLINE | ID: mdl-23612294

ABSTRACT

Graphene quantum dots are attractive candidates for solid-state quantum bits. In fact, the predicted weak spin-orbit and hyperfine interaction promise spin qubits with long coherence times. Graphene quantum dots have been extensively investigated with respect to their excitation spectrum, spin-filling sequence and electron-hole crossover. However, their relaxation dynamics remain largely unexplored. This is mainly due to challenges in device fabrication, in particular concerning the control of carrier confinement and the tunability of the tunnelling barriers, both crucial to experimentally investigate decoherence times. Here we report pulsed-gate transient current spectroscopy and relaxation time measurements of excited states in graphene quantum dots. This is achieved by an advanced device design that allows to individually tune the tunnelling barriers down to the low megahertz regime, while monitoring their asymmetry. Measuring transient currents through electronic excited states, we estimate a lower bound for charge relaxation times on the order of 60-100 ns.

SELECTION OF CITATIONS
SEARCH DETAIL
...