2,514 research outputs found

    "SAMs meet MEMS": surface modification with self-assembled monolayers for the dry-demolding of photoplastic MEMS/NEMS

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    In this contribution we demonstrate the use of self-assembled monolayers (SAMs) as anti-adhesion coating to assist the removal of photoplastic MEMS/NEMS with a patterned metal layer from the surface without wet chemical sacrificial layer etching, so-called 'dry-demolding'. The SAMs functionality here is to reduce the stiction between the surface and a thin evaporated metal film. The double-layer SAM/metal provides enough stability to support subsequent micromachining step

    Instruments and methods: a method for recording ice ablation using a low-cost ultrasonic rangefinder

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    We have adapted inexpensive ultrasonic rangefinders to measure ablation rates on the surface of a glacier.While ultrasonic rangers are commercially available for this purpose, our goal was to utilize rangefinders typically used in hobby robotics without significantly compromising performance. To correct for environmental factors that affect the speed of sound we use two ultrasonic rangefinders, one focused on a fixed target. Measurements of ablation correlate well with manual measurements with an uncertainty of about 3 cm, suggesting an accuracy comparable with other non-manual methods of recording ablation. The limitations of our rangefinder include those inherent in commercially available units as well as having less acoustical power, which results in a reduced effective range of the sensor (2m) and difficulties in detecting surfaces lying below low-density snow. Our sensor design provides a cost-effective means of increasing the spatial coverage of ice ablation measurements

    Retention of mouth-to-mouth, mouth-to-mask and mouth-to-face shield ventilation

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    Background: Retention of mouth-to-mouth, mouth-to-mask and mouth-to-face shield ventilation techniques is poorly understood.Methods: A prospective randomised clinical trial was undertaken in January 2004 in 70 candidates randomly assigned to training in mouth-to-mouth, mouth-to-mask or mouth-to-face shield ventilation. Each candidate was trained for 10 min, after which tidal volume, respiratory rate, minute volume, peak airway pressure and the presence or absence of stomach inflation were measured. 58 subjects were reassessed 1 year later and study parameters were recorded again. Data were analysed with ANOVA, \textgreekq2 and McNemar tests.Results: Tidal volume, minute volume, peak airway pressure, ventilation rate and stomach inflation rate increased significantly at reassessment with all ventilation techniques compared with the initial assessment. However, at reassessment, mean (SD) tidal volume (960 (446) vs 1008 (366) vs 1402 (302) ml; p<0.05), minute volume (12 (5) vs 13 (7) vs 18 (3) l/min; p<0.05), peak airway pressure (14 (8) vs 17 (13) vs 25 (8) cm H2O; p<0.05) and stomach inflation rate (63% vs 58% vs 100%; p<0.05) were significantly lower with mouth-to-mask and mouth-to-face shield ventilation than with mouth-to-mouth ventilation. The ventilation rate at reassessment did not differ significantly between the ventilation techniques.Conclusions: One year after a single episode of ventilation training, lay persons tended to hyperventilate; however, the degree of hyperventilation and resulting stomach inflation were lower when a mouth-to-mask or a face shield device was employed. Regular training is therefore required to retain ventilation skills; retention of skills may be better with ventilation devices

    Fluka Estimations concerning Obstacles in the LHC Magnets.

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    The effect of the impact of the full energy LHC proton beam with an object left in the beam pipe is investigated in order to assess the conditions for a superconducting magnet's quench. FLUKA simulations indicate that a quench would happen about 20 m downstream from the impact for a current through the object being several orders of magnitude lower than the nominal beam current. If such a strict current limit (decreasing with increasing obstacle's thickness) is not exceeded in operational conditions, the obstacle might be destroyed without causing any quench, being the vaporization time dependent on its shape and movement. However, any rise of the traversing current above the mentioned limit would result in a beam dump and the obstacle remaining in the machine

    Henry Lewis McMurry

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    Autoresuscitation (Lazarus phenomenon) after termination of cardiopulmonary resuscitation - a scoping review.

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    Autoresuscitation describes the return of spontaneous circulation after termination of resuscitation (TOR) following cardiac arrest (CA). We aimed to identify phenomena that may lead to autoresuscitation and to provide guidance to reduce the likelihood of it occurring. We conducted a literature search (Google Scholar, MEDLINE, PubMed) and a scoping review according to PRISMA-ScR guidelines of autoresuscitation cases where patients undergoing CPR recovered circulation spontaneously after TOR with the following criteria: 1) CA from any cause; 2) CPR for any length of time; 3) A point was reached when it was felt that the patient had died; 4) Staff declared the patient dead and stood back. No further interventions took place; 5) Later, vital signs were observed. 6) Vital signs were sustained for more than a few seconds, such that staff had to resume active care. Sixty-five patients with ROSC after TOR were identified in 53 articles (1982-2018), 18 (28%) made a full recovery. Almost a third made a full recovery after autoresuscitation. The following reasons for and recommendations to avoid autoresuscitation can be proposed: 1) In asystole with no reversible causes, resuscitation efforts should be continued for at least 20 min; 2) CPR should not be abandoned immediately after unsuccessful defibrillation, as transient asystole can occur after defibrillation; 3) Excessive ventilation during CPR may cause hyperinflation and should be avoided; 4) In refractory CA, resuscitation should not be terminated in the presence of any potentially-treatable cardiac rhythm; 5) After TOR, the casualty should be observed continuously and ECG monitored for at least 10 min

    Proton Magnetic Resonance Spectroscopy and Illness Stage in Schizophrenia-A Systematic Review and Meta-Analysis

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    Background It is not known whether regional brain N-acetyl aspartate (NAA) changes in the progression from prodrome to chronic schizophrenia. We used effect size meta-analysis to determine which brain regions show the most robust reductions in NAA first episode and chronic schizophrenia as measured by proton magnetic resonance spectroscopy and to determine whether these changes are present in individuals at high risk of developing schizophrenia. Methods We identified 131 articles, of which 97 met inclusion criteria. Data were separated by stage of illness (at risk, first episode schizophrenia, chronic schizophrenia) and by brain region. For each region, mean and SD of the NAA measure was extracted. Results Significant reductions in NAA levels were found in frontal lobe, temporal lobe, and thalamus in both patient groups (effect size > .3; p < .01). In individuals at high risk of schizophrenia (of whom approximately 20% would be expected to undergo transition to psychosis), significant NAA reductions were present in thalamus (effect size = .78; p < .05), with reductions at trend level only in temporal lobe (effect size = .32; p < .1), and no reductions in frontal lobe (effect size = .05; p = .5). Conclusions These data suggest that schizophrenia is associated with loss of neuronal integrity in frontal and temporal cortices and in the thalamus and suggest that these changes in the frontal and temporal lobe might occur in the transition between the at-risk phase and the first episode

    Levodopa reverses gait asymmetries related to anhedoniaand magical ideation

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    Animals and men turn preferentially away from the hemisphere with the more active dopamine (DA) system. Consistent with the idea of a right-hemispheric hyperdopaminergia in schizophrenia, a leftsided turning bias was described for unmedicated psychotic patients. We investigated the modulating role of DA and schizophrenia-like thought on whole-body turns in a controlled double-blind study. The number of veers to either side when walking blindfolded straight ahead (20 meter) was assessed in 40 healthy righthanded men (20 men received levodopa, the remaining participants placebo). Side preferences were analyzed in terms of individuals' positive (Magical Ideation, MI) and negative (Physical Anhedonia, PhysAn) schizotypal features. In the placebo group, increasing MI scores were related to increasing left-sided veering and increasing PhysAn scores were related to increasing right-sided veering. In the levodopa group, this relationship between preferred veering side and type of schizotypy was reversed. The finding in the placebo group suggests an association between MI and a relative right-hemispheric hyperdopaminergia. Unexpectedly, levodopa did not enhance this veering bias, but reversed it, suggesting that psychosis-protective mechanisms exist in the healthy positive "schizotypic” brain. Also unexpectedly, levodopa made "anhedonics” veer like "magics” after placebo, suggesting that DA agonists suppress negative schizotypal symptom

    FLUKA simulations for the optimization of the Beam Loss Monitors

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    The collimation system in the beam cleaning insertion IR7 of the Large Hadron Collider (LHC) is expected to clean the primary halo and the secondary radiation of a beam with unprecedented energy and intensity. Accidental beam losses can therefore entail severe consequences to the hardware of the machine. Thus, protection mechanisms, e.g. beam abort, must be instantaneously triggered by a set of Beam Loss Monitors (BLM's). The readings in the BLM's couple the losses from various collimators, thus rendering the identification of any faulty unit rather complex. In the present study the detailed geometry of IR7 is upgraded with the insertion of the BLM's, and the Monte Carlo FLUKA transport code is used to estimate the individual contribution of every collimator to the showers detected in each BLM
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