363 research outputs found
Engineering intracellular biomineralization and biosensing by a magnetic protein
Remote measurement and manipulation of biological systems can be achieved using magnetic techniques, but a missing link is the availability of highly magnetic handles on cellular or molecular function. Here we address this need by using high-throughput genetic screening in yeast to select variants of the iron storage ferritin (Ft) that display enhanced iron accumulation under physiological conditions. Expression of Ft mutants selected from a library of 10[superscript 7] variants induces threefold greater cellular iron loading than mammalian heavy chain Ft, over fivefold higher contrast in magnetic resonance imaging, and robust retention on magnetic separation columns. Mechanistic studies of mutant Ft proteins indicate that improved magnetism arises in part from increased iron oxide nucleation efficiency. Molecular-level iron loading in engineered Ft enables detection of individual particles inside cells and facilitates creation of Ft-based intracellular magnetic devices. We demonstrate construction of a magnetic sensor actuated by gene expression in yeast.National Institutes of Health (U.S.) (Grant DP2-OD002114)National Institutes of Health (U.S.) (Grant R01-NS076462)National Institutes of Health (U.S.) (Grant R01-MH103160)Thomas and Stacey Siebel Foundation (Fellowship)McGovern Institute for Brain Research at MIT (Friends of the McGovern Institute Fellowship
Results of a multicenter, prospective trial of thoracic endovascular aortic repair for blunt thoracic aortic injury (RESCUE trial)
ObjectiveTo evaluate the early outcomes of patients undergoing thoracic endovascular aortic repair for blunt thoracic aortic injuries.MethodsA prospective, nonrandomized, multicenter trial using the Medtronic Valiant Captivia stent graft was conducted at 20 sites in North America. Fifty patients with blunt thoracic aortic injuries were enrolled between April 2010 and January 2012 and will be followed for 5 years. The injuries were classified into categories (grades I-IV) based on severity: intimal tear, intramural hematoma, pseudoaneurysm, or rupture. The primary end point was 30-day all-cause mortality. Secondary end points were adverse events occurring within 30 days that were related to the procedure, device or aorta, and aortic-related mortality. Technical success was measured as successful device delivery and deployment.ResultsSeventy-six percent (38/50) of patients were male with mean age of 41 ± 17 years. Fifty-one Medtronic Valiant Captivia thoracic stent grafts and a single Talent thoracic stent graft were implanted within a median of 1.0 days following injury (mean, 1.8 ± 4.0 days). Seventy percent (35/50) of aortic injuries were grade III or higher, including one patient with free rupture. Mean injury severity score was 38 ± 14. Fifty-four percent of stent grafts were â€26 mm (28/52). The left subclavian artery was completely covered in 40% of patients (20/50) and partially covered in 18% of patients (9/50). Four patients underwent subclavian artery revascularization: one at the time of the endograft procedure and three others after developing arm ischemia after the initial endograft procedure. Cerebral spinal fluid was drained in two patients. The median procedure time was 91 minutes, and median hospital stay was 12 days. There was 100% successful device delivery and deployment. Four (8%) patients died within 30 days. Nonfatal adverse events within 30 days that were related to the procedure, device, or aorta were experienced by 12% (6/50) of patients. No nonfatal adverse events related to the device were reported; a single death was conservatively adjudicated as device-, procedure-, and aorta-related because of insufficient information. No patient developed spinal cord injury, and there were no cerebrovascular accidents. However, one patient had an anoxic brain injury following aortic rupture. No patient underwent conversion to open repair or required an endovascular reintervention.ConclusionsBased on the early outcomes, the Medtronic Valiant Captivia stent graft appears to be a promising treatment modality for blunt thoracic aortic injuries. Long-term follow-up is necessary to substantiate the effectiveness of thoracic endovascular aortic repair in treatment of blunt thoracic aortic injuries
Riemann-Finsler geometry and Lorentz-violating kinematics
Effective field theories with explicit Lorentz violation are intimately
linked to Riemann-Finsler geometry. The quadratic single-fermion restriction of
the Standard-Model Extension provides a rich source of pseudo-Riemann-Finsler
spacetimes and Riemann-Finsler spaces. An example is presented that is
constructed from a 1-form coefficient and has Finsler structure complementary
to the Randers structure.Comment: 19 page
Determining a Role for Ventromedial Prefrontal Cortex in Encoding Action-Based Value Signals During Reward-Related Decision Making
Considerable evidence has emerged to implicate ventromedial prefrontal cortex in encoding expectations of future reward during value-based decision making. However, the nature of the learned associations upon which such representations depend is much less clear. Here, we aimed to determine whether expected reward representations in this region could be driven by actionâoutcome associations, rather than being dependent on the associative value assigned to particular discriminative stimuli. Subjects were scanned with functional magnetic resonance imaging while performing 2 variants of a simple reward-related decision task. In one version, subjects made choices between 2 different physical motor responses in the absence of discriminative stimuli, whereas in the other version, subjects chose between 2 different stimuli that were randomly assigned to different responses on a trial-by-trial basis. Using an extension of a reinforcement learning algorithm, we found activity in ventromedial prefrontal cortex tracked expected future reward during the action-based task as well as during the stimulus-based task, indicating that value representations in this region can be driven by actionâoutcome associations. These findings suggest that ventromedial prefrontal cortex may play a role in encoding the value of chosen actions irrespective of whether those actions denote physical motor responses or more abstract decision options
Emotions in context: examining pervasive affective sensing systems, applications, and analyses
Pervasive sensing has opened up new opportunities for measuring our feelings and understanding our behavior by monitoring our affective states while mobile. This review paper surveys pervasive affect sensing by examining and considering three major elements of affective pervasive systems, namely; âsensingâ, âanalysisâ, and âapplicationâ. Sensing investigates the different sensing modalities that are used in existing real-time affective applications, Analysis explores different approaches to emotion recognition and visualization based on different types of collected data, and Application investigates different leading areas of affective applications. For each of the three aspects, the paper includes an extensive survey of the literature and finally outlines some of challenges and future research opportunities of affective sensing in the context of pervasive computing
Pair production of the heavy leptons in future high energy linear e^{+}e^{-} colliders
The littlest Higgs model with T-parity predicts the existence of the T-odd
particles, which can only be produced in pair. We consider pair production of
the T-odd leptons in future high energy linear collider ().
Our numerical results show that, as long as the T-odd leptons are not too
heavy, they can be copiously produced and their possible signals might be
detected via the processes in future
experiments.Comment: Discussions added, typos and references correcte
Efficacy and safety of filgotinib in methotrexate-naive patients with rheumatoid arthritis with poor prognostic factors: post hoc analysis of FINCH 3
OBJECTIVE: This analysis evaluated efficacy and safety of filgotinib, a Janus-associated kinase 1-preferential inhibitor, in methotrexate (MTX)-naive patients with rheumatoid arthritis (RA) with multiple poor prognostic factors (PPFs). METHODS: This was a post hoc analysis of the phase III, randomised, double-blind, active-controlled, FINCH 3 study (clinicaltrials.gov NCT02886728). Patients received once-daily oral filgotinib 200 or 100âmg plus once-weekly oral MTX â€20âmg (FIL200 + MTXâand FIL100 + MTX), filgotinib 200âmg monotherapy (FIL200), or oral MTX monotherapy (MTX-mono) for up to 52 weeks. PPFs investigated were seropositivity for rheumatoid factor or anticyclic citrullinated peptide antibodies, high-sensitivity C reactive protein (CRP) â„4âmg/L, Disease Activity Score in 28 joints with CRP (DAS28(CRP)) >5.1, and presence of erosions. Filgotinib efficacy and safety in patients with all four PPFs at baseline were explored versus MTX-mono within this subgroup and compared informally with the overall population. RESULTS: Of 1249 patients in FINCH 3, 510 (40.8%) had all PPFs. Efficacy of FIL200 + MTX among these patients was comparable to the overall population, with higher rates of 20%/50%/70% improvement from baseline by American College of Rheumatology criteria, DAS28(CRP) <2.6, and remission; greater improvement in physical function and pain; and better inhibition of structural damage relative to MTX-mono. FIL100 + MTXâand FIL200 were not consistently more efficacious versus MTX-mono. Safety of filgotinib in patients with PPFs was comparable to the overall population; no new safety signals were observed. CONCLUSION: FIL200 + MTX efficacy and safety in patients with multiple PPFs were similar to the overall population
Thin film solar cell inflatable ultraviolet rigidizable deployment hinge
A flexible inflatable hinge includes curable resin for rigidly positioning panels of solar cells about the hinge in which wrap around contacts and flex circuits are disposed for routing power from the solar cells to the power bus further used for grounding the hinge. An indium tin oxide and magnesium fluoride coating is used to prevent static discharge while being transparent to ultraviolet light that cures the embedded resin after deployment for rigidizing the inflatable hinge
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