2,670 research outputs found

    On a question of Beidleman and Robinson

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    In (1, Theorem A), Beidleman and Robinson proved that if a group satisfies the permutizer condition, it is soluble, its chief factors have order a prime number or 4 and G induces the full group of automorphisms in the chief factors of order 4. In this paper, we show that the converse of this theorem is false by showing some counterexamples. We also find some sufficient conditions for a group satisfying the converse of that theorem to satisfy the permutizer condition

    The College Admissions problem with lower and common quotas

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    We study two generalised stable matching problems motivated by the current matching scheme used in the higher education sector in Hungary. The first problem is an extension of the College Admissions problem in which the colleges have lower quotas as well as the normal upper quotas. Here, we show that a stable matching may not exist and we prove that the problem of determining whether one does is NP-complete in general. The second problem is a different extension in which, as usual, individual colleges have upper quotas, but, in addition, certain bounded subsets of colleges have common quotas smaller than the sum of their individual quotas. Again, we show that a stable matching may not exist and the related decision problem is NP-complete. On the other hand, we prove that, when the bounded sets form a nested set system, a stable matching can be found by generalising, in non-trivial ways, both the applicant-oriented and college-oriented versions of the classical Gale–Shapley algorithm. Finally, we present an alternative view of this nested case using the concept of choice functions, and with the aid of a matroid model we establish some interesting structural results for this case

    The value of FDG-PET in patients with painful total knee arthroplasty

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    Purpose: The purpose of this study was to evaluate 18F-fluorodeoxyglucose (FDG) uptake in patients with painful total knee arthroplasty and to relate FDG uptake to the location of soft tissue pain. Methods: Twenty-eight patients with painful total knee arthroplasty had a clinical examination, standard radiographs, CT measurement of rotation of the femoral component and FDG-PET (18 PET/CT, 10 PET). The diagnosis of infection was based on microbiological examinations of surgical specimens (n=12) or clinical follow-up for at least 6 months (n=16), 99mTc-labelled monoclonal antibody scintigraphy and joint aspiration. Results: Twenty-seven of 28 patients presented with diffuse synovial FDG uptake. Additional focal extrasynovial FDG uptake was observed in 19 knees. Twenty-four of the 28 patients had a diagnosis of internal femoral malrotation. The remaining four patients showed no rotation (0°) and 3°, 4° and 7° of external rotation, respectively. Three patients presented with the additional diagnosis of an infected total knee replacement. Pain was described as diffuse (n=10) or focal (n=18). In two knees a relationship between pain location and FDG uptake was observed. Of ten patients with a severe internal femoral component rotation (>6°), seven had focal uptake, four in the femoral periosteum and three in the tibial periosteum. The difference between knees with severe malrotation and the remaining knees was not significant (p=1.000, Fisher's Exact Test). Conclusion: Diffuse synovial and focal extrasynovial FDG-PET uptake is commonly found in patients with malrotation of the femoral component and is not related to pain location. The information provided by FDG-PET does not contribute to the diagnosis and management of individual patients with persistent pain after total knee replacemen

    Quantitative approach for cardiac risk assessment and interpretation in tuberculosis drug development

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    Cardiotoxicity is among the top drug safety concerns, and is of specific interest in tuberculosis, where this is a known or potential adverse event of current and emerging treatment regimens. As there is a need for a tool, beyond the QT interval, to quantify cardiotoxicity early in drug development, an empirical decision tree based classifier was developed to predict the risk of Torsades de pointes (TdP). The cardiac risk algorithm was developed using pseudo-electrocardiogram (ECG) outputs derived from cardiac myocyte electromechanical model simulations of increasing concentrations of 96 reference compounds which represented a range of clinical TdP risk. The algorithm correctly classified 89% of reference compounds with moderate sensitivity and high specificity (71 and 96%, respectively) as well as 10 out of 12 external validation compounds and the anti-TB drugs moxifloxacin and bedaquiline. The cardiac risk algorithm is suitable to help inform early drug development decisions in TB and will evolve with the addition of emerging data

    Critical Path to Tuberculosis Drug Regimens: Global collaboration to accelerate development of novel drug regimens and rapid drug susceptibility tests for tuberculosis

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    The Critical Path to Tuberculosis Drug Regimens (CPTR) initiative aims to support the rational deployment of new tuberculosis (TB) therapies by speeding the development and impact of new and markedly improved drug regimens as well as rapid drug susceptibility tests. Co-founded by the Bill & Melinda Gates Foundation, the Critical Path Institute, and the TB Alliance in 2010, CPTR is a coalition comprising the world’s leading pharmaceutical companies, product development sponsors, diagnostic companies, regulatory agencies, and civil society organizations which support and catalyze advances in regulatory science, the development of infrastructure, and other progress needed to accelerate the pace of development and introduction of novel regimens and rapid drug susceptibility tests. This manuscript summarizes the work of two subgroups within CPTR, the Regulatory Sciences and Rapid Drug Susceptibility Test consortia, and their efforts to drive innovation. These consortia are supported by a robust TB clinical data platform, which continues to evolve through contributions of contemporary TB clinical trial data sets as well as whole genome sequence level data from isolates across the globe. Examples of innovation are described and include a recently-qualified drug development tool and emerging programs to support the development of clinical trial simulation tools

    EuroEco (European Health Economic Trial on Home Monitoring in ICD Patients): a provider perspective in five European countries on costs and net financial impact of follow-up with or without remote monitoring

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    Aim: Remote follow-up (FU) of implantable cardiac defibrillators (ICDs) allows for fewer in-office visits in combination with earlier detection of relevant findings. Its implementation requires investment and reorganization of care. Providers (physicians or hospitals) are unsure about the financial impact. The primary end-point of this randomized prospective multicentre health economic trial was the total FU-related cost for providers, comparing Home Monitoring facilitated FU (HM ON) to regular in-office FU (HM OFF) during the first 2 years after ICD implantation. Also the net financial impact on providers (taking national reimbursement into account) and costs from a healthcare payer perspective were evaluated. Methods and results: Atotal of 312 patients with VVI-or DDD-ICD implants from 17 centres in six EU countries were randomised to HMON or OFF, of which 303 were eligible for data analysis. For all contacts (in-office, calendar-or alert-triggered web-based review, discussions, calls) time-expenditure was tracked. Country-specific cost parameters were used to convert resource use into monetary values. Remote FU equipment itself was not included in the cost calculations. Given only two patients from Finland (one in each group) a monetary valuation analysis was not performed for Finland. Average age was 62.4 +/- 13.1 years, 81% were male, 39% received a DDD system, and 51% had a prophylactic ICD. Resource use with HM ON was clearly different: less FU visits (3.79 +/- 1.67 vs. 5.53 +/- 2.32; P < 0.001) despite a small increase of unscheduled visits (0.95 +/- 1.50 vs. 0.62 +/- 1.25; P < 0.005), more non-office-based contacts (1.95+3.29 vs. 1.01 +/- 2.64; P < 0.001), more Internet sessions (11.02 +/- 15.28 vs. 0.06 +/- 0.31; P < 0.001) and more in-clinic discussions (1.84 +/- 4.20 vs. 1.28 +/- 2.92; P < 0.03), but with numerically fewer hospitalizations (0.67 +/- 1.18 vs. 0.85 +/- 1.43, P = 0.23) and shorter length-of-stay (6.31 +/- 15.5 vs. 8.26 +/- 18.6; P = 0.27), although not significant. For the whole study population, the total FU cost for providers was not different for HM ON vs. OFF [mean (95% CI): (sic)204 169-238) vs. (sic)213 (182-243); range for difference ((sic)-36 to 54), NS]. From a payer perspective, FU-related costs were similar while the total cost per patient (including other physician visits, examinations, and hospitalizations) was numerically (but not significantly) lower. There was no difference in the net financial impact on providers [profit of (sic)408 (327-489) vs. (sic)400 (345-455); range for difference ((sic)-104 to 88), NS], but there was heterogeneity among countries, with less profit for providers in the absence of specific remote FU reimbursement (Belgium, Spain, and the Netherlands) and maintained or increased profit in cases where such reimbursement exists (Germany and UK). Quality of life (SF-36) was not different. Conclusion: For all the patients as a whole, FU-related costs for providers are not different for remote FU vs. purely in-office FU, despite reorganized care. However, disparity in the impact on provider budget among different countries illustrates the need for proper reimbursement to ensure effective remote FU implementation

    Concept of an ionizing time-domain matter-wave interferometer

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    We discuss the concept of an all-optical and ionizing matter-wave interferometer in the time domain. The proposed setup aims at testing the wave nature of highly massive clusters and molecules, and it will enable new precision experiments with a broad class of atoms, using the same laser system. The propagating particles are illuminated by three pulses of a standing ultraviolet laser beam, which detaches an electron via efficient single photon-absorption. Optical gratings may have periods as small as 80 nm, leading to wide diffraction angles for cold atoms and to compact setups even for very massive clusters. Accounting for the coherent and the incoherent parts of the particle-light interaction, we show that the combined effect of phase and amplitude modulation of the matter waves gives rise to a Talbot-Lau-like interference effect with a characteristic dependence on the pulse delay time.Comment: 25 pages, 5 figure

    Multigram scale synthesis of polycyclic lactones and evaluation of antitumor and other biological properties

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    An efficient four-step synthesis of tetracyclic lactones from 1,4-benzodioxine-2-carboxylic acid was developed. Ellipticine derivatives exhibit antitumor activity however only a few derivatives without carbazole subunit have been studied to date. Herein, several tetracyclic lactones were synthesized and biologically evaluated. Several compounds (2a, 3a, 4a and 5a) were found to be inhibitors of the KrasWnt pathway. The lactone 2a also exerted a potent inhibition of Tau protein translation and was shown to have capacity for CYP1A1-bioactivation. The results obtained are further evidence of the therapeutic potential of tetracyclic lactones related to ellipticine. Molecular modeling studies showed that compound 2a is inserted between helix a3 and a4 of the KRas protein making interactions with the hydrophobic residues Phe90, Glu91, Ile9364, Hie94, Leu133 and Tyr137and a hydrogen bond with residue Arg97

    MERLIN: a novel BRET-based proximity biosensor for studying mitochondria–ER contact sites

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    The contacts between the ER and mitochondria play a key role in cellular functions such as the exchange of lipids and calcium between both organelles, as well as in apoptosis and autophagy signaling. The molecular architecture and spatiotemporal regulation of these distinct contact regions remain obscure and there is a need for new tools that enable tackling these questions. Here, we present a new bioluminescence resonance energy transfer-based biosensor for the quantitative analysis of distances between the ER and mitochondria that we call MERLIN (Mitochondria-ER Length Indicator Nanosensor). The main advantages of MERLIN compared with available alternatives are that it does not rely on the formation of artificial physical links between the two organelles, which could lead to artifacts, and that it allows to study contact site reversibility and dynamics. We show the applicability of MERLIN by characterizing the role of the mitochondrial dynamics machinery on the contacts of this organelle with the ER.We thank Peter McCormick for helpful advice and discussion and Carolin Stegmuller, Sabine Schafer, Iris Koch, Maria Zarani, Astrid Schauss, Christian Jungst, Felix Babatz, and Marina Nikolova for technical support. This work has been partially supported by the Deutsche Forschungsgemeinschaft (FOR2036 GA1641/2-1 and GA1641/2-2) and the European Research Council (StG 309966)

    Recommendations to Optimize the Use of Volumetric MRI in Huntington's Disease Clinical Trials

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    Volumetric magnetic resonance imaging (vMRI) has been widely studied in Huntington's disease (HD) and is commonly used to assess treatment effects on brain atrophy in interventional trials. Global and regional trajectories of brain atrophy in HD, with early involvement of striatal regions, are becoming increasingly understood. However, there remains heterogeneity in the methods used and a lack of widely-accessible multisite, longitudinal, normative datasets in HD. Consensus for standardized practices for data acquisition, analysis, sharing, and reporting will strengthen the interpretation of vMRI results and facilitate their adoption as part of a pathobiological disease staging system. The Huntington's Disease Regulatory Science Consortium (HD-RSC) currently comprises 37 member organizations and is dedicated to building a regulatory science strategy to expedite the approval of HD therapeutics. Here, we propose four recommendations to address vMRI standardization in HD research: (1) a checklist of standardized practices for the use of vMRI in clinical research and for reporting results; (2) targeted research projects to evaluate advanced vMRI methodologies in HD; (3) the definition of standard MRI-based anatomical boundaries for key brain structures in HD, plus the creation of a standard reference dataset to benchmark vMRI data analysis methods; and (4) broad access to raw images and derived data from both observational studies and interventional trials, coded to protect participant identity. In concert, these recommendations will enable a better understanding of disease progression and increase confidence in the use of vMRI for drug development
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