624 research outputs found
Blinded sample size recalculation in multiple composite population designs with normal data and baseline adjustments
No full textRobustness of testing procedures for confirmatory subpopulation analyses based on a continuous biomarker
No full text With the advent of personalized medicine, clinical trials studying treatment effects in subpopulations are receiving increasing attention. The objectives of such studies are, besides demonstrating a treatment effect in the overall population, to identify subpopulations, based on biomarkers, where the treatment has a beneficial effect. Continuous biomarkers are often dichotomized using a threshold to define two subpopulations with low and high biomarker levels. If there is insufficient information on the dependence structure of the outcome on the biomarker, several thresholds may be investigated. The nested structure of such subpopulations is similar to the structure in group sequential trials. Therefore, it has been proposed to use the corresponding critical boundaries to test such nested subpopulations. We show that for biomarkers with a prognostic effect that is not adjusted for in the statistical model, the variability of the outcome may vary across subpopulations which may lead to an inflation of the family-wise type 1 error rate. Using simulations we quantify the potential inflation of testing procedures based on group sequential designs. Furthermore, alternative hypotheses tests that control the family-wise type 1 error rate under minimal assumptions are proposed. The methodological approaches are illustrated by a trial in depression. </jats:p
Supplemental material for Robustness of testing procedures for confirmatory subpopulation analyses based on a continuous biomarker
No full textSupplemental Material for Robustness of testing procedures for confirmatory subpopulation analyses based on a continuous biomarker by Alexandra Christine Graf, Gernot Wassmer, Tim Friede, Roland Gerard Gera and Martin Posch in Statistical Methods in Medical Research</p
Stent-retriever assisted vacuum-locked extraction (SAVE) versus a direct aspiration first pass technique (ADAPT) for acute stroke: data from the real-world
No full textAbstract Background Embolectomy is the standard of care in acute ischemic stroke (AIS) caused by large vessel occlusion (LVO). Aim of this study was to compare two techniques: A Direct Aspiration First Pass Technique (ADAPT) and Stent-retriever Assisted Vacuum-locked Extraction (SAVE) stratified by the occluded vessel. Methods One hundred seventy-one patients (71 male) treated between January 2014 and September 2017 with AIS due to LVO of the anterior circulation (55 carotid T, 94 M1, 22 M2) were included. Treatment techniques were divided into two categories: ADAPT and SAVE. Primary endpoints were successful reperfusion (mTICI ≥2b), near-perfect reperfusion (mTICI ≥2c) and groin puncture to reperfusion time. Secondary endpoints were the number of device-passes, first-pass reperfusion, the frequency of emboli to new territory (ENT), clinical outcome at 90 days, and the frequency of symptomatic intracranial hemorrhage (sICH). Analysis was performed on an intention to treat basis. Results Overall, SAVE resulted in significant higher rates of successful reperfusion (mTICI≥2b) compared to ADAPT (93.5% vs 75.0%; p = 0.006). After stratification for the occluded vessel only the carotid T remained significant with higher rates of near-perfect reperfusion (mTICI≥2c) (55.2% vs 15.4%; p = 0.025), while for successful reperfusion a trend remained (93.1% vs 65.4%; p = 0.10). Groin to reperfusion times were not significantly different. Secondary analysis revealed higher rates of first-pass successful reperfusion (59.6% vs 33.3%; p = 0.019), higher rates of first-pass near-perfect reperfusion in the carotid T (35.4% vs 16.7%; p = 0.038) and a lower number of device-passes overall (median 1 IQR 1–2 vs 2 IQR 2–3; p < 0.001) and in the carotid T (median 2 IQR 1.3 vs 3 IQR 2–5; p < 0.001) for SAVE. Clinical outcome and safety parameters were comparable between groups. Conclusions Embolectomy using SAVE appears superior to ADAPT, especially for carotid T occlusions with regard to reperfusion success
Change in Femoral Offset after Closed Reduction and Dynamic Hip Screw Osteosynthesis Via Lateral Approach in Patients with Medial Femoral Neck Fracture: A Retrospective Analysis
No full textObjective Closed reduction and dynamic hip screw (DHS) osteosynthesis are preferred as joint‐preserving therapy in case of medial femoral neck fractures (MFNFs). A change in the femoral offset (CFO) can cause gait abnormality, impingement, or greater trochanteric pain syndrome. It is unknown whether the femoral offset (FO) can be postoperatively fully restored. The aim of the study was to investigate the extent of a possible CFO in hip joints after DHS osteosynthesis in the case of an MFNF. Methods In this retrospective study, 104 patients (mean age: 71.02 years, men: n = 50, women: n = 54) with MFNF who underwent closed reduction and DHS osteosynthesis were analyzed by postoperative x‐rays to assess CFO between the operated (OS) and nonoperated joint side (NOS). The studies covered the time period 2010–2020. A statistical comparison was performed between the mean values of FO between OS and NOS, taking into account patient age, gender, and fracture severity. Results All operated hip joints showed a CFO. In 76.0% (79 of 104), the FO decreased (FOD), and in 24.0% (25 of 104), the FO increased (FOI). A critical CFO (>15% CFO) was detected in 52.9% (55 of 104). In hip joints with postoperative FOD, the mean FO between NOS (49.15 mm [±6.56]) and OS (39.32 mm [±7.87]) and in hip joints with postoperative FOI the mean FO between NOS (41.59 [±8.21]) and OS (47.27 [±6.68]) differed significantly ( p 0.001) and caput–collum–diaphyseal angle (CCD; r S : 0.34; p > 0.001) correlated with postoperative CFO. FOD was found in hip joints with a preoperative FO >44 mm and CCD 134°. Conclusion Closed reduction and DHS osteosynthesis in patients with MFNF result in a clustered significant CFO. The individual FO should be taken into account pre‐ and intraoperatively to avoid a postoperative extensive CFO.Open-Access-Publikationsfonds 202
THE SCIENCE OF SPEECH: DEVELOPING A COMPUTATIONAL MODEL FOR DIGITAL COMMUNICATION AND ITS RAMIFICATIONS FOR AUTHOR IDENTIFICATION IN CYBERSECURITY
No full textGreat strides have been made in identifying an author on the web by analyzing keystroke input, even down to determining what operating system the person was writing on at the time. Likewise, studying the author’s semantics and syntax provides helpful clues as to the identity of the author and whether or not the author is attempting to commit a forgery of some kind. However, most parse trees focus on either the human, or the machine, side of the Human-Machine Interface (HMI). Incorporating both sides of the HMI better accounts for the unique digital signature every web author creates by analyzing stylometry and keystroke dynamics. This research could be instrumental not only in finding malicious actors on the web, but also in distinguishing humans from machines by the way they use words. Thus, combining typing times with part-of-speech (POS) tags demonstrates crucial differences in where authors are likely to spend the most time in sentence composition.Approved for public release; distribution is unlimited.CivilianSFShttp://archive.org/details/thescienceofspee109456489
Cryptogamen-flora, enthaltend die abbildung und beschreibung der vorzüglichsten cryptogamen Deutschlands und der angrenzenden länder ...
No full textPart 2 has t.-p.: Die pilze ... 1875.Mode of access: Internet
Validation of the extended thrombolysis in cerebral infarction score in a real world cohort.
No full textBackgroundA thrombolysis in cerebral infarction (TICI) score of 2b is defined as a good recanalization result although the reperfusion may only cover 50% of the affected territory. An additional mTICI2c category was introduced to further differentiate between mTICI scores. Despite the new mTICI2c category, mTICI2b still covers a range of 50-90% reperfusion which might be too imprecise to predict neurological improvement after therapy.AimTo compare the 7-point "expanded TICI" (eTICI) scale with the traditional mTICI in regard to predict functional independence at 90 days.MethodsRetrospective review of 225 patients with large artery occlusion. Angiograms were graded by 2 readers according the 7-point eTICI score (0% = eTICI0; reduced clot = eTICI1; 1-49% = eTICI2a, 50-66% = eTICI2b50; 67-89% = eTICI2b67, 90-99% = eTICI2c and complete reperfusion = eTICI3) and the conventional mTICI score. The ability of e- and mTICI to predict favorable outcome at 90days was compared.ResultsGiven the ROC analysis eTICI was the better predictor of favorable outcome (p-value 0.047). Additionally, eTICI scores 2b50, 2b67 and 2c (former mTICI2b) were significantly superior at predicting the probability of a favorable outcome at 90 days after endovascular therapy with a p-value of 0.033 (probabilities of 17% for mTICI2b50, 24% for mTICI2b67 and 54% for mTICI2c vs. 36% for mTICI2b).ConclusionsThe 7-point eTICI allows for a more accurate outcome prediction compared to the mTICI score because it refines the broad range of former mTICI2b results
Compressive Membrane Action in Immersed Tubes: A Finite Element Study
No full textCompressive membrane action is a phenomenon commonly found in reinforced concrete structures after significant cracking and deformation have taken place. In this thesis report, the potential benefit of CMA in immersed tubes subjected to fires is quantified through a finite element study. Furthermore, sensitivity studies are conducted in order to determine the boundary conditions necessary in immersed tubes to induce CMA.Civil Engineering | Structural Engineerin
- …
