45 research outputs found

    Maximal adaptive-decision speedups in quantum-state readout

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    The average time TT required for high-fidelity readout of quantum states can be significantly reduced via a real-time adaptive decision rule. An adaptive decision rule stops the readout as soon as a desired level of confidence has been achieved, as opposed to setting a fixed readout time tft_f. The performance of the adaptive decision is characterized by the "adaptive-decision speedup," tf/Tt_f/T. In this work, we reformulate this readout problem in terms of the first-passage time of a particle undergoing stochastic motion. This formalism allows us to theoretically establish the maximum achievable adaptive-decision speedups for several physical two-state readout implementations. We show that for two common readout schemes (the Gaussian latching readout and a readout relying on state-dependent decay), the speedup is bounded by 44 and 22, respectively, in the limit of high single-shot readout fidelity. We experimentally study the achievable speedup in a real-world scenario by applying the adaptive decision rule to a readout of the nitrogen-vacancy-center (NV-center) charge state. We find a speedup of 2\approx 2 with our experimental parameters. In addition, we propose a simple readout scheme for which the speedup can, in principle, be increased without bound as the fidelity is increased. Our results should lead to immediate improvements in nanoscale magnetometry based on spin-to-charge conversion of the NV-center spin, and provide a theoretical framework for further optimization of the bandwidth of quantum measurements.Comment: 18 pages, 11 figures. This version is close to the published versio

    Right cranial lung lobe torsion after a diaphragmatic rupture repair in a Jack Russell terrier

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    A seven-year-old male Jack Russell terrier was presented with a history of coughing, generalised weakness and lethargy 10 days after an abdominal coeliotomy to repair a large diaphragmatic rupture. Thoracic radiographs demonstrated a soft tissue mass in the midcaudal right thoracic cavity. Ultrasonographic studies, bronchoscopy and subsequent exploratory thoracotomy confirmed a diagnosis of a right cranial lung lobe torsion (LLT), with an anomalous caudodorsal displacement of the affected lobe. LLT should be considered as a differential diagnosis for respiratory tract disease following diaphragmatic rupture repair

    Phase II Open Label Study of Valproic Acid in Spinal Muscular Atrophy

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    UNLABELLED:Preliminary in vitro and in vivo studies with valproic acid (VPA) in cell lines and patients with spinal muscular atrophy (SMA) demonstrate increased expression of SMN, supporting the possibility of therapeutic benefit. We performed an open label trial of VPA in 42 subjects with SMA to assess safety and explore potential outcome measures to help guide design of future controlled clinical trials. Subjects included 2 SMA type I ages 2-3 years, 29 SMA type II ages 2-14 years and 11 type III ages 2-31 years, recruited from a natural history study. VPA was well-tolerated and without evident hepatotoxicity. Carnitine depletion was frequent and temporally associated with increased weakness in two subjects. Exploratory outcome measures included assessment of gross motor function via the modified Hammersmith Functional Motor Scale (MHFMS), electrophysiologic measures of innervation including maximum ulnar compound muscle action potential (CMAP) amplitudes and motor unit number estimation (MUNE), body composition and bone density via dual-energy X-ray absorptiometry (DEXA), and quantitative blood SMN mRNA levels. Clear decline in motor function occurred in several subjects in association with weight gain; mean fat mass increased without a corresponding increase in lean mass. We observed an increased mean score on the MHFMS scale in 27 subjects with SMA type II (p<or=0.001); however, significant improvement was almost entirely restricted to participants <5 years of age. Full length SMN levels were unchanged and Delta7SMN levels were significantly reduced for 2 of 3 treatment visits. In contrast, bone mineral density (p<or=0.0036) and maximum ulnar CMAP scores (p<or=0.0001) increased significantly. CONCLUSIONS:While VPA appears safe and well-tolerated in this initial pilot trial, these data suggest that weight gain and carnitine depletion are likely to be significant confounding factors in clinical trials. This study highlights potential strengths and limitations of various candidate outcome measures and underscores the need for additional controlled clinical trials with VPA targeting more restricted cohorts of subjects. TRIAL REGISTRATION:ClinicalTrials.gov

    SMA CARNI-VAL Trial Part I: Double-Blind, Randomized, Placebo-Controlled Trial of L-Carnitine and Valproic Acid in Spinal Muscular Atrophy

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    Valproic acid (VPA) has demonstrated potential as a therapeutic candidate for spinal muscular atrophy (SMA) in vitro and in vivo.Two cohorts of subjects were enrolled in the SMA CARNIVAL TRIAL, a non-ambulatory group of "sitters" (cohort 1) and an ambulatory group of "walkers" (cohort 2). Here, we present results for cohort 1: a multicenter phase II randomized double-blind intention-to-treat protocol in non-ambulatory SMA subjects 2-8 years of age. Sixty-one subjects were randomized 1:1 to placebo or treatment for the first six months; all received active treatment the subsequent six months. The primary outcome was change in the modified Hammersmith Functional Motor Scale (MHFMS) score following six months of treatment. Secondary outcomes included safety and adverse event data, and change in MHFMS score for twelve versus six months of active treatment, body composition, quantitative SMN mRNA levels, maximum ulnar CMAP amplitudes, myometry and PFT measures.At 6 months, there was no difference in change from the baseline MHFMS score between treatment and placebo groups (difference = 0.643, 95% CI = -1.22-2.51). Adverse events occurred in >80% of subjects and were more common in the treatment group. Excessive weight gain was the most frequent drug-related adverse event, and increased fat mass was negatively related to change in MHFMS values (p = 0.0409). Post-hoc analysis found that children ages two to three years that received 12 months treatment, when adjusted for baseline weight, had significantly improved MHFMS scores (p = 0.03) compared to those who received placebo the first six months. A linear regression analysis limited to the influence of age demonstrates young age as a significant factor in improved MHFMS scores (p = 0.007).This study demonstrated no benefit from six months treatment with VPA and L-carnitine in a young non-ambulatory cohort of subjects with SMA. Weight gain, age and treatment duration were significant confounding variables that should be considered in the design of future trials.Clinicaltrials.gov NCT00227266

    What is Intellectual Freedom Today? An Invitation to Think the Event

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    The pubmed search term “pastoris[Title] AND (express[Title] OR produced[Title] OR expression[Title] OR production[Title])” yielded 877 hits in December 2008, dated from 1987 to 2009. At the same time, the search term “pastoris[Title] AND (bioreactor[Title] OR fed-batch[Title] OR continuous[Title] OR fermentations[Title] OR large-scale[Title] OR fermentation[Title] OR pilot[Title])” returned 92 hits –published between 1990 and 2009. This analysis is somewhat superficial and ostentatious, but it suggests that the majority of researchers publishing on Pichia use it as a tool for rather than an object of their work. This is not to say that the majority should change their focus, but in fact researchers sometimes face difficulties when the need to obtain useful amounts of a target protein produced in Pichia calls for scale-up from the benchtop protocols to a bioreactor-based process. This chapter attempts to provide a reliable protocol for AOX1-driven bioreactor production of secreted scFvs or other proteins

    SMA CARNI-VAL TRIAL PART II: A Prospective, Single-Armed Trial of L-Carnitine and Valproic Acid in Ambulatory Children with Spinal Muscular Atrophy

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    Multiple lines of evidence have suggested that valproic acid (VPA) might benefit patients with spinal muscular atrophy (SMA). The SMA CARNIVAL TRIAL was a two part prospective trial to evaluate oral VPA and l-carnitine in SMA children. Part 1 targeted non-ambulatory children ages 2–8 in a 12 month cross over design. We report here Part 2, a twelve month prospective, open-label trial of VPA and L-carnitine in ambulatory SMA children.This study involved 33 genetically proven type 3 SMA subjects ages 3–17 years. Subjects underwent two baseline assessments over 4–6 weeks and then were placed on VPA and L-carnitine for 12 months. Assessments were performed at baseline, 3, 6 and 12 months. Primary outcomes included safety, adverse events and the change at 6 and 12 months in motor function assessed using the Modified Hammersmith Functional Motor Scale Extend (MHFMS-Extend), timed motor tests and fine motor modules. Secondary outcomes included changes in ulnar compound muscle action potential amplitudes (CMAP), handheld dynamometry, pulmonary function, and Pediatric Quality of Life Inventory scores.Twenty-eight subjects completed the study. VPA and carnitine were generally well tolerated. Although adverse events occurred in 85% of subjects, they were usually mild and transient. Weight gain of 20% above body weight occurred in 17% of subjects. There was no significant change in any primary outcome at six or 12 months. Some pulmonary function measures showed improvement at one year as expected with normal growth. CMAP significantly improved suggesting a modest biologic effect not clinically meaningful.This study, coupled with the CARNIVAL Part 1 study, indicate that VPA is not effective in improving strength or function in SMA children. The outcomes used in this study are feasible and reliable, and can be employed in future trials in SMA

    Repair-Mediated Duplication by Capture of Proximal Chromosomal DNA Has Shaped Vertebrate Genome Evolution

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    DNA double-strand breaks (DSBs) are a common form of cellular damage that can lead to cell death if not repaired promptly. Experimental systems have shown that DSB repair in eukaryotic cells is often imperfect and may result in the insertion of extra chromosomal DNA or the duplication of existing DNA at the breakpoint. These events are thought to be a source of genomic instability and human diseases, but it is unclear whether they have contributed significantly to genome evolution. Here we developed an innovative computational pipeline that takes advantage of the repetitive structure of genomes to detect repair-mediated duplication events (RDs) that occurred in the germline and created insertions of at least 50 bp of genomic DNA. Using this pipeline we identified over 1,000 probable RDs in the human genome. Of these, 824 were intra-chromosomal, closely linked duplications of up to 619 bp bearing the hallmarks of the synthesis-dependent strand-annealing repair pathway. This mechanism has duplicated hundreds of sequences predicted to be functional in the human genome, including exons, UTRs, intron splice sites and transcription factor binding sites. Dating of the duplication events using comparative genomics and experimental validation revealed that the mechanism has operated continuously but with decreasing intensity throughout primate evolution. The mechanism has produced species-specific duplications in all primate species surveyed and is contributing to genomic variation among humans. Finally, we show that RDs have also occurred, albeit at a lower frequency, in non-primate mammals and other vertebrates, indicating that this mechanism has been an important force shaping vertebrate genome evolution

    Hyperammonemia and systemic inflammatory response syndrome predicts presence of hepatic encephalopathy in dogs with congenital portosystemic shunts

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    Hepatic encephalopathy (HE) is an important cause of morbidity and mortality in patients with liver disease. The pathogenesis of he is incompletely understood although ammonia and inflammatory cytokines have been implicated as key mediators. To facilitate further mechanistic understanding of the pathogenesis of HE, a large number of animal models have been developed which often involve the surgical creation of an anastomosis between the hepatic portal vein and the caudal vena cava. One of the most common congenital abnormalities in dogs is a congenital portosystemic shunt (cpss), which closely mimics these surgical experimental models of HE. Dogs with a cPSS often have clinical signs which mimic clinical signs observed in humans with HE. Our hypothesis is that the pathogenesis of HE in dogs with a cPSS is similar to humans with HE. The aim of the study was to measure a range of clinical, haematological and biochemical parameters, which have been linked to the development of HE in humans, in dogs with a cPSS and a known HE grade. One hundred and twenty dogs with a cPSS were included in the study and multiple regression analysis of clinical, haematological and biochemical variables revealed that plasma ammonia concentrations and systemic inflammatory response syndrome scores predicted the presence of HE. Our findings further support the notion that the pathogenesis of canine and human HE share many similarities and indicate that dogs with cPSS may be an informative spontaneous model of human HE. Further investigations on dogs with cPSS may allow studies on HE to be undertaken without creating surgical models of HE thereby allowing the number of large animals used in animal experimentation to be reduced

    The Use of Functional Data Analysis to Evaluate Activity in a Spontaneous Model of Degenerative Joint Disease Associated Pain in Cats

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    Introduction and objectives: accelerometry is used as an objective measure of physical activity in humans and veterinary species. In cats, one important use of accelerometry is in the study of therapeutics designed to treat degenerative joint disease (DJD) associated pain, where it serves as the most widely applied objective outcome measure. These analyses have commonly used summary measures, calculating the mean activity per-minute over days and comparing between treatment periods. While this technique has been effective, information about the pattern of activity in cats is lost. In this study, functional data analysis was applied to activity data from client-owned cats with (n = 83) and without (n = 15) DJD. Functional data analysis retains information about the pattern of activity over the 24-hour day, providing insight into activity over time. We hypothesized that 1) cats without DJD would have higher activity counts and intensity of activity than cats with DJD; 2) that activity counts and intensity of activity in cats with DJD would be inversely correlated with total radiographic DJD burden and total orthopedic pain score; and 3) that activity counts and intensity would have a different pattern on weekends versus weekdays. Results and conclusions: results showed marked inter-cat variability in activity. Cats exhibited a bimodal pattern of activity with a sharp peak in the morning and broader peak in the evening. Results further showed that this pattern was different on weekends than weekdays, with the morning peak being shifted to the right (later). Cats with DJD showed different patterns of activity from cats without DJD, though activity and intensity were not always lower; instead both the peaks and troughs of activity were less extreme than those of the cats without DJD. Functional data analysis provides insight into the pattern of activity in cats, and an alternative method for analyzing accelerometry data that incorporates fluctuations in activity across the day.UCR::Vicerrectoría de Docencia::Ciencias Sociales::Facultad de Ciencias Económicas::Escuela de Estadístic
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