5,895 research outputs found

    Space processes for extended low-G testing

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    Results of an investigation of verifying the capabilities of space processes in ground based experiments at low-g periods are presented. Limited time experiments were conducted with the processes. A valid representation of the complete process cycle was achieved at low-g periods ranging from 40 to 390 seconds. A minimum equipment inventory, is defined. A modular equipment design, adopted to assure low cost and high program flexibility, is presented as well as procedures and data established for the synthesis and definition of dedicated and mixed rocket payloads

    Electron spin relaxation of N@C60 in CS2

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    We examine the temperature dependence of the relaxation times of the molecules N@C60 and N@C70 (which comprise atomic nitrogen trapped within a carbon cage) in liquid CS2 solution. The results are inconsistent with the fluctuating zero field splitting (ZFS) mechanism, which is commonly invoked to explain electron spin relaxation for S > 1/2 spins in liquid solution, and is the mechanism postulated in the literature for these systems. Instead, we find a clear Arrhenius temperature dependence for N@C60, indicating the spin relaxation is driven primarily by an Orbach process. For the asymmetric N@C70 molecule, which has a permanent non-zero ZFS, we resolve an additional relaxation mechanism caused by the rapid reorientation of its ZFS. We also report the longest coherence time (T2) ever observed for a molecular electron spin, being 0.25 ms at 170K.Comment: 6 pages, 6 figures V2: Updated to published versio

    An Enhanced Nonlinear Critical Gradient for Electron Turbulent Transport due to Reversed Magnetic Shear

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    The first nonlinear gyrokinetic simulations of electron internal transport barriers (e-ITBs) in the National Spherical Torus Experiment show that reversed magnetic shear can suppress thermal transport by increasing the nonlinear critical gradient for electron-temperature-gradient-driven turbulence to three times its linear critical value. An interesting feature of this turbulence is nonlinearly driven off-midplane radial streamers. This work reinforces the experimental observation that magnetic shear is likely an effective way of triggering and sustaining e-ITBs in magnetic fusion devices.Comment: 4 pages, 5 figure

    An Enhanced Nonlinear Critical Gradient for Electron Turbulent Transport due to Reversed Magnetic Shear

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    The first nonlinear gyrokinetic simulations of electron internal transport barriers (e-ITBs) in the National Spherical Torus Experiment show that reversed magnetic shear can suppress thermal transport by increasing the nonlinear critical gradient for electron-temperature-gradient-driven turbulence to three times its linear critical value. An interesting feature of this turbulence is nonlinearly driven off-midplane radial streamers. This work reinforces the experimental observation that magnetic shear is likely an effective way of triggering and sustaining e-ITBs in magnetic fusion devices.Comment: 4 pages, 5 figure

    Severe Lumbar Disability Is Associated With Decreased Psoas Cross-Sectional Area in Degenerative Spondylolisthesis

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    Study Design: Retrospective cohort. Objectives: Alterations in lumbar paraspinal muscle cross-sectional area (CSA) may correlate with lumbar pathology. The purpose of this study was to compare paraspinal CSA in patients with degenerative spondylolisthesis and severe lumbar disability to those with mild or moderate lumbar disability, as determined by the Oswestry Disability Index (ODI). Methods: We retrospectively reviewed the medical records of 101 patients undergoing lumbar fusion for degenerative spondylolisthesis. Patients were divided into ODI score ≤40 (mild/moderate disability, MMD) and ODI score \u3e40 (severe disability, SD) groups. The total CSA of the psoas and paraspinal muscles were measured on preoperative magnetic resonance imaging (MRI). Results: There were 37 patients in the SD group and 64 in the MMD group. Average age and body mass index were similar between groups. For the paraspinal muscles, we were unable to demonstrate any significant differences in total CSA between the groups. Psoas muscle CSA was significantly decreased in the SD group compared with the MMD group (1010.08 vs 1178.6 mm2, P =.041). Multivariate analysis found that psoas CSA in the upper quartile was significantly protective against severe disability (P =.013). Conclusions: We found that patients with severe lumbar disability had no significant differences in posterior lumbar paraspinal CSA when compared with those with mild/moderate disability. However, severely disabled patients had significantly decreased psoas CSA, and larger psoas CSA was strongly protective against severe disability, suggestive of a potential association with psoas atrophy and worsening severity of lumbar pathology. © The Author(s) 2018

    PCN185 A Multi-Country Retrospective Study of Patient Characteristics and Treatment Patterns in Chronic Myeloid Leukemia

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    Opicapone, a Novel Catechol-O-methyl Transferase Inhibitor, for Treatment of Parkinson\u27s Disease Off Episodes

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    Parkinson\u27s Disease (PD) is a common neurodegenerative disorder and the leading cause of disability. It causes significant morbidity and disability through a plethora of symptoms, including movement disorders, sleep disturbances, and cognitive and psychiatric symptoms. The traditional pathogenesis theory of PD involves the loss of dopaminergic neurons in the substantia nigra (SN). Classically, treatment is pursued with an assortment of medications that are directed at overcoming this deficiency with levodopa being central to most treatment plans. Patients taking levodopa tend to experience off episodes with decreasing medication levels, causing large fluctuations in their symptoms. These off episodes are disturbing and a source of morbidity for these patients. Opicapone is a novel, peripherally acting Catechol-O-methyl transferase (COMT) inhibitor that is used as adjunctive therapy to carbidopa/levodopa for treatment and prevention of off episodes. It has been approved for use as an adjunct to levodopa since 2016 in Europe and has recently (April 2020) gained FDA approval for use in the USA. By inhibiting COMT, opicapone slows levodopa metabolism and increases its availability. Several clinical studies demonstrated significant improvement in treatment efficacy and reduction in duration of off episodes. The main side effect demonstrated was dyskinesia, mostly with the 100mg dose, which is higher than the approved, effective dose of 50mg. Post-marketing surveillance and analysis are required to further elucidate its safety profile and contribute to patient selection. This paper reviews the seminal and latest evidence in the treatment of PD off episodes with the novel drug Opicapone, including efficacy, safety, and clinical indications

    Chronic pain treatment strategies in Parkinson’s disease

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    Neurological disorders, including Parkinson’s disease (PD), have increased in prevalence and are expected to further increase in the coming decades. In this regard, PD affects around 3% of the population by age 65 and up to 5% of people over the age of 85. PD is a widely described, physically and mentally disabling neurodegenerative disorder. One symptom often poorly recognized and under-treated by health care providers despite being reported as the most common non-motor symptom is the finding of chronic pain. Compared to the general population of similar age, PD patients suffer from a significantly higher level and prevalence of pain. The most common form of pain reported by Parkinson’s patients is of musculoskeletal origin. One of the most used combination drugs for PD is Levodopa-Carbidopa, a dopamine precursor that is converted to dopamine by the action of a naturally occurring enzyme called DOPA decarboxylase. Pramipexole, a D2 dopamine agonist, and apomorphine, a dopamine agonist, and Rotigotine, a dopamine receptor agonist, have showed efficacy on PD-associated pain. Other treatments that have shown efficacy in treating pain of diverse etiologies are acetaminophen, Nonsteroidal anti-inflammatory drugs (NSAIDs), and cyclooxygenase-2 (COX-2) inhibitors. Opioids and opioid-like medications such as oxycodone, morphine, tramadol, and codeine are also commonly employed in treatment of chronic pain in PD. Other opioid related medications such as Tapentadol, a central-acting oral analgesic with combined opioid and noradrenergic properties, and Targinact, a combination of the opioid agonist oxycodone and the opioid antagonist naloxone have shown improvement in pain. Anticonvulsants such as gabapentin, pregabalin, lamotrigine, carbamazepine and tricyclic antidepressants (TCAs) can be trialed when attempting to manage chronic pain in PD. The selective serotonin and noradrenaline reuptake inhibitors (SNRIs) also possess pain relieving and antidepressant properties, but carry less of the risk of anticholinergic side effects seen in TCAs. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has been shown in multiple studies to be effective against various types of PD associated pain symptoms. Massage therapy (MT) is one of the most common forms of complementary and alternative medicine. Studies have shown that pressure applied during MT may stimulate vagal activity, promoting reduced anxiety and pain, as well as increasing levels of serotonin. In a survey study of PD patients, rehabilitative therapy and physical therapy were rated as the most effective for pain reduction, though with only temporary relief but these studies were uncontrolled. Yoga has been studied for patients with a wide array of neurological disorders. In summary, PD pathology is thought to have a modulating effect on pain sensation, which could amplify pain. This could help explain a portion of the higher incidence of chronic pain felt by PD patients. A treatment plan can be devised that may include dopaminergic agents, acetaminophen, NSAIDs, opioids, antidepressants, physical therapies, DBS and other options discussed in this review. A thorough assessment of patient history and physical examination should be made in patients with PD so chronic pain may be managed effectively

    Chronic pain treatment strategies in Parkinson’s disease

    Get PDF
    Neurological disorders, including Parkinson’s disease (PD), have increased in prevalence and are expected to further increase in the coming decades. In this regard, PD affects around 3% of the population by age 65 and up to 5% of people over the age of 85. PD is a widely described, physically and mentally disabling neurodegenerative disorder. One symptom often poorly recognized and under-treated by health care providers despite being reported as the most common non-motor symptom is the finding of chronic pain. Compared to the general population of similar age, PD patients suffer from a significantly higher level and prevalence of pain. The most common form of pain reported by Parkinson’s patients is of musculoskeletal origin. One of the most used combination drugs for PD is Levodopa-Carbidopa, a dopamine precursor that is converted to dopamine by the action of a naturally occurring enzyme called DOPA decarboxylase. Pramipexole, a D2 dopamine agonist, and apomorphine, a dopamine agonist, and Rotigotine, a dopamine receptor agonist, have showed efficacy on PD-associated pain. Other treatments that have shown efficacy in treating pain of diverse etiologies are acetaminophen, Nonsteroidal anti-inflammatory drugs (NSAIDs), and cyclooxygenase-2 (COX-2) inhibitors. Opioids and opioid-like medications such as oxycodone, morphine, tramadol, and codeine are also commonly employed in treatment of chronic pain in PD. Other opioid related medications such as Tapentadol, a central-acting oral analgesic with combined opioid and noradrenergic properties, and Targinact, a combination of the opioid agonist oxycodone and the opioid antagonist naloxone have shown improvement in pain. Anticonvulsants such as gabapentin, pregabalin, lamotrigine, carbamazepine and tricyclic antidepressants (TCAs) can be trialed when attempting to manage chronic pain in PD. The selective serotonin and noradrenaline reuptake inhibitors (SNRIs) also possess pain relieving and antidepressant properties, but carry less of the risk of anticholinergic side effects seen in TCAs. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has been shown in multiple studies to be effective against various types of PD associated pain symptoms. Massage therapy (MT) is one of the most common forms of complementary and alternative medicine. Studies have shown that pressure applied during MT may stimulate vagal activity, promoting reduced anxiety and pain, as well as increasing levels of serotonin. In a survey study of PD patients, rehabilitative therapy and physical therapy were rated as the most effective for pain reduction, though with only temporary relief but these studies were uncontrolled. Yoga has been studied for patients with a wide array of neurological disorders. In summary, PD pathology is thought to have a modulating effect on pain sensation, which could amplify pain. This could help explain a portion of the higher incidence of chronic pain felt by PD patients. A treatment plan can be devised that may include dopaminergic agents, acetaminophen, NSAIDs, opioids, antidepressants, physical therapies, DBS and other options discussed in this review. A thorough assessment of patient history and physical examination should be made in patients with PD so chronic pain may be managed effectively
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