280 research outputs found

    Observation of sub-natural linewidths for cold atoms in a magneto-optic trap

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    We have studied the absorption of a weak probe beam through cold rubidium atoms in a magneto-optic trap. The absorption spectrum shows two peaks with the smaller peak having linewidth as small as 28% of the natural linewidth. The modification happens because the laser beams used for trapping also drive the atoms coherently between the ground and excited states. This creates ``dressed'' states whose energies are shifted depending on the strength of the drive. Linewidth narrowing occurs due to quantum coherence between the dressed states. The separation of the states increases with laser intensity and detuning, as expected from this model.Comment: 8 pages, 4 figure

    Experimental study of SRAT/SME foaming by Illinois Institute of Technology

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    This report summarizes the results of experiments performed by IIT in an effort to understand the fundamental science involved in the stable foam formation in the Defense Waste Processing Facility`s (DWPF`s) Chemical Processing Cell (CPC). The results of this testing will be confirmed in an experimental apparatus designed to be prototypic of DWPF CPC processing

    The effects of community interventions on unplanned healthcare use in patients with multimorbidity: a systematic review

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    OBJECTIVES: To summarise the impact of community-based interventions for multimorbid patients on unplanned healthcare use. The prevalence of multimorbidity (co-existence of multiple chronic conditions) is rapidly increasing and affects one-third of the global population. Patients with multimorbidity have complex healthcare needs and greater unplanned healthcare usage. Community-based interventions allow for continued care of patients outside hospitals, but few studies have explored the effects of these interventions on unplanned healthcare usage. DESIGN: A systematic review was conducted. MEDLINE, EMBASE, PsychINFO and Cochrane Library online databases were searched. Studies were screened and underwent risk of bias assessment. Data were synthesised using narrative synthesis. SETTING: Community-based interventions. PARTICIPANTS: Patients with multimorbidity. MAIN OUTCOME MEASURES: Unplanned healthcare usage. RESULTS: Thirteen studies, including a total of 6148 participants, were included. All included studies came from high-income settings and had elderly populations. All studies measured emergency department attendances as their primary outcome. Risk of bias was generally low. Most community interventions were multifaceted with emphasis on education, self-monitoring of symptoms and regular follow-ups. Four studies looked at improved care coordination, advance care planning and palliative care. All 13 studies found a decrease in emergency department visits post-intervention with risk reduction ranging from 0 (95% confidencec interval [CI]: -0.37 to 0.37) to 0.735 (95% CI: 0.688-0.785). CONCLUSIONS: Community-based interventions have potential to reduce emergency department visits in patients with multimorbidity. Identification of specific successful components of interventions was challenging given the overlaps between interventions. Policymakers should recognise the importance of community interventions and aim to integrate aspects of these into existing healthcare structures. Future research should investigate the impact of such interventions with broader participant characteristics

    Molecular dynamics simulation of nanocolloidal amorphous silica particles: Part II

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    Explicit molecular dynamics simulations were applied to a pair of amorphous silica nanoparticles of diameter 3.2 nm immersed in a background electrolyte. Mean forces acting between the pair of silica nanoparticles were extracted at four different background electrolyte concentrations. Dependence of the inter-particle potential of mean force on the separation and the silicon to sodium ratio, as well as on the background electrolyte concentration, are demonstrated. The pH was indirectly accounted for via the ratio of silicon to sodium used in the simulations. The nature of the interaction of the counter-ions with charged silica surface sites (deprotonated silanols) was also investigated. The effect of the sodium double layer on the water ordering was investigated for three Si:Na+ ratios. The number of water molecules trapped inside the nanoparticles was investigated as the Si:Na+ ratio was varied. Differences in this number between the two nanoparticles in the simulations are attributed to differences in the calculated electric dipole moment. The implications of the form of the potentials for aggregation are also discussed.Comment: v1. 33 pages, 7 figures (screen-quality PDF), submitted to J. Chem. Phys v2. 15 pages, 4 tables, 6 figures. Content, author list and title changed; single space

    Psychopathology predicts the outcome of medial branch blocks with corticosteroid for chronic axial low back or cervical pain: a prospective cohort study

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    <p>Abstract</p> <p>Background</p> <p>Comorbid psychopathology is an important predictor of poor outcome for many types of treatments for back or neck pain. But it is unknown if this applies to the results of medial branch blocks (MBBs) for chronic low back or neck pain, which involves injecting the medial branch of the dorsal ramus nerves that innervate the facet joints. The objective of this study was to determine whether high levels of psychopathology are predictive of pain relief after MBB injections in the lumbar or cervical spine.</p> <p>Methods</p> <p>This was a prospective cohort study. Consecutive patients in a pain medicine practice undergoing MBBs of the lumbar or cervical facets with corticosteroids were recruited to participate. Subjects were selected for a MBB based on operationalized selection criteria and the procedure was performed in a standardized manner. Subjects completed the Brief Pain Inventory (BPI) and the Hospital Anxiety and Depression Scale (HADS) just prior to the procedure and at one-month follow up. Scores on the HADS classified the subjects into three groups based on psychiatric symptoms, which formed the primary predictor variable: <it>Low</it>, <it>Moderate</it>, or <it>High </it>levels of psychopathology. The primary outcome measure was the percent improvement in average daily pain rating one-month following an injection. Analysis of variance and chi-square were used to analyze the analgesia and functional rating differences between groups, and to perform a responder analysis.</p> <p>Results</p> <p>Eighty six (86) subjects completed the study. The <it>Low </it>psychopathology group (n = 37) reported a mean of 23% improvement in pain at one-month while the <it>High </it>psychopathology group (n = 29) reported a mean worsening of -5.8% in pain (p < .001). Forty five percent (45%) of the <it>Low </it>group had at least 30% improvement in pain versus 10% in the <it>High </it>group (p < .001). Using an analysis of covariance, no baseline demographic, social, or medical variables were significant predictors of pain improvement, nor did they mitigate the effect of psychopathology on the outcome.</p> <p>Conclusion</p> <p>Psychiatric comorbidity is associated with diminished pain relief after a MBB injection performed with steroid at one-month follow-up. These findings illustrate the importance of assessing comorbid psychopathology as part of a spine care evaluation.</p

    Quality of life, long-term survivors and long-term outcome from the ABC-02 study.

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    Background The ABC-02 (Advanced Biliary Tract Cancer) study established cisplatin and gemcitabine (CisGem) as the standard first-line chemotherapy for patients with locally advanced or metastatic biliary tract cancer (BTC). We examine quality of life (QoL), describe the long-term survivors and provide a long-term outcome.Methods A total of 410 BTC patients were randomised to receive either CisGem or gemcitabine alone (Gem); 324 patients consented to complete EORTC QLQ-C30 and EORTC QLQ-PAN26 QoL questionnaires; 268 (83%) patients returned at least one QoL questionnaire (134 in each arm). Long-term survivors were defined as those surviving over 2 years and we performed a final analysis of the primary outcome; overall survival (OS).Results Most QoL scales showed a trend favouring the combined CisGem arm, including functional and symptomatic scales, although the differences were not statistically significant. Forty-five (11%)) patients survived at least 2 years (34 received CisGem and 11 Gem) and 21 (5%) 3 years or more (14 received CisGem and 7 Gem). After a median follow-up of 9.2 months and 398 deaths, the median OS was 11.7 months for CisGem and 8.1 months for Gem (hazard ratio (HR)=0.65, 95% CI: 0.53-0.79, P<0.001).Conclusions The survival advantage of CisGem compared to Gem was not associated with an improvement or deterioration of QoL. Long-term survivors were more likely to have received CisGem and the long-term OS is identical to that previously described

    Discovery and Development of Toll-Like Receptor 4 (TLR4) Antagonists: A New Paradigm for Treating Sepsis and Other Diseases

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    Abstract. Sepsis remains the most common cause of death in intensive care units in the USA, with a current estimate of at least 750,000 cases per year, and 215,000 deaths annually. Despite extensive research still we do not quite understand the cellular and molecular mechanisms that are involved in triggering and propagation of septic injury. Endotoxin (lipopolysaccharide from Gram-negative bacteria, or LPS) has been implicated as a major cause of this syndrome. Inflammatory shock as a consequence of LPS release remains a serious clinical concern. In humans, inflammatory responses to LPS result in the release of cytokines and other cell mediators from monocytes and macrophages, which can cause fever, shock, organ failure and death. A number of different approaches have been investigated to try to treat and/or prevent the septic shock associated with infections caused by Gram-negative bacteria, including blockage of one or more of the cytokines induced by LPS. Recently several novel amphipathic compounds have been developed as direct LPS antagonists at the LPS receptor, TLR4. This review article will outline the current knowledge on the TLR4-LPS synthesis and discuss the signaling, in vitro pre-clinical and in vivo clinical evaluation of TLR4 antagonists and their potential use in sepsis and a variety of diseases such as atherosclerosis as well as hepatic and renal malfunction. KEY WORDS: drug discovery; LPS; sepsis; toll-like receptor antagonists
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