5,245 research outputs found

    Attainment of treat-to-target endpoints in SLE patients with high disease activity in the atacicept phase 2b ADDRESS II study

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    OBJECTIVE Low disease activity (LDA) and remission are emerging treat-to-target (T2T) endpoints in SLE. However, the rates at which these endpoints are met in patients with high disease activity (HDA) are unknown. Atacicept, which targets B lymphocyte stimulator and a proliferation-inducing ligand, improved disease outcomes in SLE patients with HDA (SLEDAI-2K ≥10) at baseline in the phase 2b ADDRESS II study. This is a post hoc analysis of T2T endpoints in these patients. METHODS Patients received weekly atacicept (75 or 150 mg s.c.) or placebo for 24 weeks (1:1:1 randomization). Attainment of three T2T endpoints, LDA (SLEDAI-2K ≤ 2), Lupus Low Disease Activity State (LLDAS) and remission (clinical SLEDAI-2K = 0, prednisone-equivalent ≤5mg/day and Physician’s Global Assessment <0.5), was assessed and compared with SLE Responder Index (SRI)-4 and SRI-6 response. RESULTS Of 306 randomized patients, 158 (51.6%) had baseline HDA. At week 24, 37 (23.4%) HDA patients attained LDA, 25 (15.8%) LLDAS and 17 (10.8%) remission. Each of these endpoints was more stringent than SRI-4 (n = 87; 55.1%) and SRI-6 (n = 67; 42.4%). Compared with placebo (n = 52), at week 24, patients treated with atacicept 150 mg (n = 51) were more likely to attain LDA [odds ratio (OR) 3.82 (95% CI: 1.44, 10.15), P = 0.007], LLDAS [OR 5.03 (95% CI: 1.32, 19.06), P = 0.018] or remission [OR 3.98 (95% CI: 0.78, 20.15), P = 0.095]. CONCLUSION At week 24, LDA, LLDAS and remission were more stringent than SRI-4 and SRI-6 response, were attainable in the HDA population and discriminated between treatment with atacicept 150 mg and placebo. These results suggest that T2T endpoints are robust outcome measures in SLE clinical trials and support further evaluation of atacicept in SLE. TRAIL REGISTRATION ClinicalTrials.gov, http://clinicaltrials.gov, NCT01972568

    Reconstructing pedigrees: some identifiability questions for a recombination-mutation model

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    Pedigrees are directed acyclic graphs that represent ancestral relationships between individuals in a population. Based on a schematic recombination process, we describe two simple Markov models for sequences evolving on pedigrees - Model R (recombinations without mutations) and Model RM (recombinations with mutations). For these models, we ask an identifiability question: is it possible to construct a pedigree from the joint probability distribution of extant sequences? We present partial identifiability results for general pedigrees: we show that when the crossover probabilities are sufficiently small, certain spanning subgraph sequences can be counted from the joint distribution of extant sequences. We demonstrate how pedigrees that earlier seemed difficult to distinguish are distinguished by counting their spanning subgraph sequences.Comment: 40 pages, 9 figure

    Rare B Decays with a HyperCP Particle of Spin One

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    In light of recent experimental information from the CLEO, BaBar, KTeV, and Belle collaborations, we investigate some consequences of the possibility that a light spin-one particle is responsible for the three Sigma^+ -> p mu^+ mu^- events observed by the HyperCP experiment. In particular, allowing the new particle to have both vector and axial-vector couplings to ordinary fermions, we systematically study its contributions to various processes involving b-flavored mesons, including B-Bbar mixing as well as leptonic, inclusive, and exclusive B decays. Using the latest experimental data, we extract bounds on its couplings and subsequently estimate upper limits for the branching ratios of a number of B decays with the new particle. This can serve to guide experimental searches for the particle in order to help confirm or refute its existence.Comment: 17 pages, 3 figures; discussion on spin-0 case modified, few errors corrected, main conclusions unchange

    A single-photon transistor using nano-scale surface plasmons

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    It is well known that light quanta (photons) can interact with each other in nonlinear media, much like massive particles do, but in practice these interactions are usually very weak. Here we describe a novel approach to realize strong nonlinear interactions at the single-photon level. Our method makes use of recently demonstrated efficient coupling between individual optical emitters and tightly confined, propagating surface plasmon excitations on conducting nanowires. We show that this system can act as a nonlinear two-photon switch for incident photons propagating along the nanowire, which can be coherently controlled using quantum optical techniques. As a novel application, we discuss how the interaction can be tailored to create a single-photon transistor, where the presence or absence of a single incident photon in a ``gate'' field is sufficient to completely control the propagation of subsequent ``signal'' photons.Comment: 20 pages, 4 figure

    Abbreviation definition identification based on automatic precision estimates

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    <p>Abstract</p> <p>Background</p> <p>The rapid growth of biomedical literature presents challenges for automatic text processing, and one of the challenges is abbreviation identification. The presence of unrecognized abbreviations in text hinders indexing algorithms and adversely affects information retrieval and extraction. Automatic abbreviation definition identification can help resolve these issues. However, abbreviations and their definitions identified by an automatic process are of uncertain validity. Due to the size of databases such as MEDLINE only a small fraction of abbreviation-definition pairs can be examined manually. An automatic way to estimate the accuracy of abbreviation-definition pairs extracted from text is needed. In this paper we propose an abbreviation definition identification algorithm that employs a variety of strategies to identify the most probable abbreviation definition. In addition our algorithm produces an accuracy estimate, pseudo-precision, for each strategy without using a human-judged gold standard. The pseudo-precisions determine the order in which the algorithm applies the strategies in seeking to identify the definition of an abbreviation.</p> <p>Results</p> <p>On the Medstract corpus our algorithm produced 97% precision and 85% recall which is higher than previously reported results. We also annotated 1250 randomly selected MEDLINE records as a gold standard. On this set we achieved 96.5% precision and 83.2% recall. This compares favourably with the well known Schwartz and Hearst algorithm.</p> <p>Conclusion</p> <p>We developed an algorithm for abbreviation identification that uses a variety of strategies to identify the most probable definition for an abbreviation and also produces an estimated accuracy of the result. This process is purely automatic.</p

    The Swiss cheese model of safety incidents: are there holes in the metaphor?

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    BACKGROUND: Reason's Swiss cheese model has become the dominant paradigm for analysing medical errors and patient safety incidents. The aim of this study was to determine if the components of the model are understood in the same way by quality and safety professionals. METHODS: Survey of a volunteer sample of persons who claimed familiarity with the model, recruited at a conference on quality in health care, and on the internet through quality-related websites. The questionnaire proposed several interpretations of components of the Swiss cheese model: a) slice of cheese, b) hole, c) arrow, d) active error, e) how to make the system safer. Eleven interpretations were compatible with this author's interpretation of the model, 12 were not. RESULTS: Eighty five respondents stated that they were very or quite familiar with the model. They gave on average 15.3 (SD 2.3, range 10 to 21) "correct" answers out of 23 (66.5%) – significantly more than 11.5 "correct" answers that would expected by chance (p < 0.001). Respondents gave on average 2.4 "correct" answers regarding the slice of cheese (out of 4), 2.7 "correct" answers about holes (out of 5), 2.8 "correct" answers about the arrow (out of 4), 3.3 "correct" answers about the active error (out of 5), and 4.1 "correct" answers about improving safety (out of 5). CONCLUSION: The interpretations of specific features of the Swiss cheese model varied considerably among quality and safety professionals. Reaching consensus about concepts of patient safety requires further work

    Critical change in the Fermi surface of iron arsenic superconductors at the onset of superconductivity

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    The phase diagram of a correlated material is the result of a complex interplay between several degrees of freedom, providing a map of the material's behavior. One can understand (and ultimately control) the material's ground state by associating features and regions of the phase diagram, with specific physical events or underlying quantum mechanical properties. The phase diagram of the newly discovered iron arsenic high temperature superconductors is particularly rich and interesting. In the AE(Fe1-xTx)2As2 class (AE being Ca, Sr, Ba, T being transition metals), the simultaneous structural/magnetic phase transition that occurs at elevated temperature in the undoped material, splits and is suppressed by carrier doping, the suppression being complete around optimal doping. A dome of superconductivity exists with apparent equal ease in the orthorhombic / antiferromagnetic (AFM) state as well as in the tetragonal state with no long range magnetic order. The question then is what determines the critical doping at which superconductivity emerges, if the AFM order is fully suppressed only at higher doping values. Here we report evidence from angle resolved photoemission spectroscopy (ARPES) that critical changes in the Fermi surface (FS) occur at the doping level that marks the onset of superconductivity. The presence of the AFM order leads to a reconstruction of the electronic structure, most significantly the appearance of the small hole pockets at the Fermi level. These hole pockets vanish, i. e. undergo a Lifshitz transition, at the onset of superconductivity. Superconductivity and magnetism are competing states in the iron arsenic superconductors. In the presence of the hole pockets superconductivity is fully suppressed, while in their absence the two states can coexist.Comment: Updated version accepted in Nature Physic

    s7a 4 reduction of systemic lupus flares by atacicept in a randomised placebo controlled phase iib study address ii and its extension study

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    Purpose Atacicept targets the B-cell stimulating factors, BLyS and APRIL, and has shown evidence of clinical response in patients with SLE. The 24 week Phase II ADDRESS II (NCT01972568) Study and its long-term extension (LTE; NCT02070978) provided data on disease activity with up to 48 weeks of atacicept treatment. Methods In ADDRESS II, patients were randomised (1:1:1) to receive weekly atacicept (75 or 150 mg SC injection) or placebo (PBO) for 24 weeks. Those who completed treatment were eligible to enter the LTE, to either continue on the same atacicept dose (atacicept groups), or switch from PBO to atacicept 150 mg (PBO/150 mg). The SLE flare analysis from both studies are reported here. Results The ITT population of ADDRESS II included 306 patients; 158 of whom met the predefined high disease activity (HDA) criterion (SLEDAI-2K≥10 at Screening). Of the 262 patients who completed the ADDRESS II, 253 entered the LTE. At 24 weeks in the PBO-controlled trial, cumulative incidence of severe flare was significantly reduced with atacicept 75 mg vs PBO by BILAG A (HR 0.24; p=0.0186), and with atacicept 150 mg vs PBO by SFI (HR 0.18; p=0.002). There was no difference in moderate-to-severe flare by BILAG A/2B. In the HDA subpopulation, incidence of severe flare at 24 weeks was significantly reduced with both atacicept doses vs PBO by BILAG A (75 mg HR 0.08, p=0.002; 150 mg HR 0.32, p=0.038) and SFI (75 mg HR 0.33, p=0.029; 150 mg HR 0.19, p=0.004). Incidence of moderate-to-severe flare by BILAG A/2B was significantly reduced with atacicept 150 mg vs PBO (HR 0.34, p=0.032). At 48 weeks, risk of severe flare by SFI was significantly lower with atacicept 150 mg vs the PBO/150 mg in both the ITT and HDA populations (figure 1); significant flare reductions were seen with atacicept 75 mg by BILAG A, and with both atacicept doses by BILAG A/2B vs PBO/150 mg, in the HDA subpopulation. Conclusions In this 24 week, double-blind, PBO-controlled trial, atacicept treatment was associated with significant flare reductions compared with PBO. Rates of flare continued to be low in atacicept-treated patients between weeks 24–48. Most flares occurred in HDA patients in the PBO group

    Spatially resolved transcriptomics reveals genes associated with the vulnerability of middle temporal gyrus in Alzheimer’s disease

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    Human middle temporal gyrus (MTG) is a vulnerable brain region in early Alzheimer’s disease (AD), but little is known about the molecular mechanisms underlying this regional vulnerability. Here we utilize the 10 × Visium platform to define the spatial transcriptomic profile in both AD and control (CT) MTG. We identify unique marker genes for cortical layers and the white matter, and layer-specific differentially expressed genes (DEGs) in human AD compared to CT. Deconvolution of the Visium spots showcases the significant difference in particular cell types among cortical layers and the white matter. Gene co-expression analyses reveal eight gene modules, four of which have significantly altered co-expression patterns in the presence of AD pathology. The co-expression patterns of hub genes and enriched pathways in the presence of AD pathology indicate an important role of cell–cell-communications among microglia, oligodendrocytes, astrocytes, and neurons, which may contribute to the cellular and regional vulnerability in early AD. Using single-molecule fluorescent in situ hybridization, we validated the cell-type-specific expression of three novel DEGs (e.g., KIF5A, PAQR6, and SLC1A3) and eleven previously reported DEGs associated with AD pathology (i.e., amyloid beta plaques and intraneuronal neurofibrillary tangles or neuropil threads) at the single cell level. Our results may contribute to the understanding of the complex architecture and neuronal and glial response to AD pathology of this vulnerable brain region

    Evaluation of two dairy herd reproductive performance indicators that are adjusted for voluntary waiting period

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    <p>Abstract</p> <p>Background</p> <p>Overall reproductive performance of dairy herds is monitored by various indicators. Most of them do not consider all eligible animals and do not consider different management strategies at farm level. This problem can be alleviated by measuring the proportion of pregnant cows by specific intervals after their calving date or after a fixed time period, such as the voluntary waiting period. The aim of this study was to evaluate two reproductive performance indicators that consider the voluntary waiting period at the herd. The two indicators were: percentage of pregnant cows in the herd after the voluntary waiting period plus 30 days (PV30) and percentage of inseminated cows in the herd after the voluntary waiting period plus 30 days (IV30). We wanted to assess how PV30 and IV30 perform in a simulation of herds with different reproductive management and physiology and to compare them to indicators of reproductive performance that do not consider the herd voluntary waiting period.</p> <p>Methods</p> <p>To evaluate the reproductive indicators we used the SimHerd-program, a stochastic simulation model, and 18 scenarios were simulated. The scenarios were designed by altering the reproductive management efficiency and the status of reproductive physiology of the herd. Logistic regression models, together with receiver operating characteristics (ROC), were used to examine how well the reproductive performance indicators could discriminate between herds of different levels of reproductive management efficiency or reproductive physiology.</p> <p>Results</p> <p>The logistic regression models with the ROC analysis showed that IV30 was the indicator that best discriminated between different levels of management efficiency followed by PV30, calving interval, 200-days not-in calf-rate (NotIC200), in calf rate at100-days (IC100) and a fertility index. For reproductive physiology the ROC analysis showed that the fertility index was the indicator that best discriminated between different levels, followed by PV30, NotIC200, IC100 and the calving interval. IV30 could not discriminate between the two levels.</p> <p>Conclusion</p> <p>PV30 is the single best performance indicator for estimating the level of both herd management efficiency and reproductive physiology followed by NotIC200 and IC100. This indicates that PV30 could be a potential candidate for inclusion in dairy herd improvement schemes.</p
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