4,774 research outputs found
Tests of the Gravitational Inverse-Square Law
We review recent experimental tests of the gravitational inverse-square law
and the wide variety of theoretical considerations that suggest the law may
break down in experimentally accessible regions.Comment: 81 pages, 10 figures, submitted by permission of the Annual Review of
Nuclear and Particle Science. Final version of this material is scheduled to
appear in the Annual Review of Nuclear and Particle Science Vol. 53, to be
published in December 2003 by Annual Reviews, http://AnnualReviews.or
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Regulation of sensory nerve conduction velocity (SCV) of human bodies responding to annual temperature variations in natural environments
The extensive research interests in environmental temperature can be linked to human productivity/performance as well as comfort and health; while the mechanisms of physiological indices responding to temperature variations remain incompletely understood. This study adopted a physiological sensory nerve conduction velocity (SCV) as a temperature-sensitive biomarker to explore the thermoregulatory mechanisms of human responding to annual temperatures. The measurements of subjects’ SCV (over 600 samples) were conducted in a naturally ventilated environment over all four seasons. The results showed a positive correlation between SCV and annual temperatures and a Boltzmann model was adopted to depict the S-shaped trend of SCV with operative temperatures from 5 °C to 40 °C. The SCV increased linearly with operative temperatures from 14.28 °C to 20.5 °C and responded sensitively for 10.19 °C - 24.59 °C, while tended to be stable beyond that. The subjects’ thermal sensations were linearly related to SCV, elaborating the relation between human physiological regulations and subjective thermal perception variations. The findings reveal the body SCV regulatory characteristics in different operative temperature intervals, thereby giving a deeper insight into human autonomic thermoregulation and benefiting for built environment designs, meantime minimizing the temperature-invoked risks to human health and well-being
Mean-Payoff Optimization in Continuous-Time Markov Chains with Parametric Alarms
Continuous-time Markov chains with alarms (ACTMCs) allow for alarm events
that can be non-exponentially distributed. Within parametric ACTMCs, the
parameters of alarm-event distributions are not given explicitly and can be
subject of parameter synthesis. An algorithm solving the -optimal
parameter synthesis problem for parametric ACTMCs with long-run average
optimization objectives is presented. Our approach is based on reduction of the
problem to finding long-run average optimal strategies in semi-Markov decision
processes (semi-MDPs) and sufficient discretization of parameter (i.e., action)
space. Since the set of actions in the discretized semi-MDP can be very large,
a straightforward approach based on explicit action-space construction fails to
solve even simple instances of the problem. The presented algorithm uses an
enhanced policy iteration on symbolic representations of the action space. The
soundness of the algorithm is established for parametric ACTMCs with
alarm-event distributions satisfying four mild assumptions that are shown to
hold for uniform, Dirac and Weibull distributions in particular, but are
satisfied for many other distributions as well. An experimental implementation
shows that the symbolic technique substantially improves the efficiency of the
synthesis algorithm and allows to solve instances of realistic size.Comment: This article is a full version of a paper accepted to the Conference
on Quantitative Evaluation of SysTems (QEST) 201
Simulation-based analysis of micro-robots swimming at the center and near the wall of circular mini-channels
Swimming micro robots have great potential in biomedical applications such as targeted drug delivery, medical diagnosis, and destroying blood clots in arteries. Inspired by swimming micro organisms, micro robots can move in biofluids with helical tails attached to their bodies. In order to design and navigate micro robots, hydrodynamic characteristics of the flow field must be understood well. This work presents computational fluid dynamics (CFD) modeling and analysis of the flow due to the motion of micro robots that consist of magnetic heads and helical tails inside fluid-filled channels akin to bodily conduits; special emphasis is on the effects of the radial position of the robot. Time-averaged velocities, forces, torques, and efficiency of the micro robots placed in the channels are analyzed as functions of rotation frequency, helical pitch (wavelength) and helical radius (amplitude) of the tail. Results indicate that robots move faster and more efficiently near the wall than at the center of the channel. Forces acting on micro robots are asymmetrical due to the chirality of the robot’s tail and its motion. Moreover, robots placed near the wall have a different flow pattern around the head when compared to in-center and unbounded swimmers. According to simulation results, time-averaged for-ward velocity of the robot agrees well with the experimental values measured previously for a robot with almost the same dimensions
Quantitative immuno-mass spectrometry imaging of skeletal muscle dystrophin
Emerging and promising therapeutic interventions for Duchenne muscular dystrophy (DMD) are confounded by the challenges of quantifying dystrophin. Current approaches have poor precision, require large amounts of tissue, and are difficult to standardize. This paper presents an immuno-mass spectrometry imaging method using gadolinium (Gd)-labeled anti-dystrophin antibodies and laser ablation-inductively coupled plasma-mass spectrometry to simultaneously quantify and localize dystrophin in muscle sections. Gd is quantified as a proxy for the relative expression of dystrophin and was validated in murine and human skeletal muscle sections following k-means clustering segmentation, before application to DMD patients with different gene mutations where dystrophin expression was measured up to 100 µg kg−1 Gd. These results demonstrate that immuno-mass spectrometry imaging is a viable approach for pre-clinical to clinical research in DMD. It rapidly quantified relative dystrophin in single tissue sections, efficiently used valuable patient resources, and may provide information on drug efficacy for clinical translation
Alteration of Hypothalamic–Pituitary–Thyroid Axis Function in Non-Small-Cell Lung Cancer Patients
The aim of this study was to evaluate the hypothalamic–pituitary–thyroid (HPT) axis function in patients suffering from lung cancer. Thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH), free thyroxine (FT4), interleukin (IL)-2, and melatonin serum levels were measured in blood samples collected every 4 hours for 24 hours from 11 healthy participants (H; ages 35-53 years) and 9 patients suffering from non-small-cell lung cancer (C; ages 43-63 years). Relationships between hormone levels overall and over time of day were evaluated within and among groups. A prominent circadian rhythm with peaks near midnight was present for TSH and melatonin serum levels in both H and C, indicating similar synchronization of the main body clock to the 24-hour environmental light–dark cycle. As regards 24-hour means in H and C, TSH was lower in C, whereas TRH, FT4, and IL-2 were higher in C, with no difference in melatonin levels. Simple linear regression, FT4 versus TRH, showed a positive correlation in H..
Development of a core outcome set to use in the research and assessment of malignant bowel obstruction: protocol for the RAMBO study
INTRODUCTION: Studies regarding the management of malignant bowel obstruction (MBO) report conflicting findings. This is partly due to different outcome measures being used to evaluate severity of MBO and the response to treatments. Furthermore, current outcome measures focus mainly on measurable physiological parameters which may not correlate strongly with patient-defined quality of life. The development of core outcome sets allows a consistent approach to evaluating clinical conditions taking into consideration patient, healthcare professional and researcher viewpoints. It follows an internationally recognised standard methodology. We present a protocol for the development of a core outcome set for Research and Assessment of MBO (RAMBO). METHODS: RAMBO is a multicentre study, comprising of four phases: a systematic review to examine current scope of outcome measures associated with MBO (phase I). Interviews with patients, companions and healthcare professionals will explore priorities and preferences for care and outcomes (phase II). An expert panel meeting will collate the findings into a set of outcomes (phase III), refined by consensus through a Delphi survey with key stakeholders (phase IV). The final set of outcomes will be ratified at a consensus meeting. Each step will actively include patient partners. Thematic analysis and descriptive statistics will be used to analyse qualitative and quantitative data, respectively. ETHICS AND DISSEMINATION: Ethical approval was obtained (Wales REC 5, REF: 19/LO/1876). Study participants and relevant stakeholders will be updated with newsletters and a lay summary at the end of the study. Abstracts will be submitted to national and international conferences, result papers will be submitted to peer-reviewed, open access journals. TRIAL AND PROSPERO REGISTRATION NUMBERS: Core Outcome Measures in Effectiveness Trials (1402); Systematic Literature Review (CRD42019150648); Rapid Review (CRD42020176393)
Critical pathway for patients undergoing aortic-surgery: Impact on postoperative care at an intensive care unit in Sweden
A cluster randomized controlled trial of child-focused psychiatric consultation and a school systems-focused intervention to reduce aggression
While school-based anti-bullying programs are widely used, there have been few controlled trials of effectiveness. This study compared the effect of manualized School Psychiatric Consultation (SPC), CAPSLE (a systems and mentalization focused whole school intervention), and treatment-as-usual (TAU) in reducing aggression and victimization among elementary school children.Participants were 1,345 third to fifth graders in nine elementary schools in a medium-sized Midwestern city who took part in a cluster-level randomized controlled trial with stratified restricted allocation, to assess efficacy after two years of active intervention and effectiveness after one year of minimal input maintenance intervention. Outcome measures included peer and self-reports of bullying, bystanding, and mentalizing behavior and classroom behavioral observations of disruptive and off-task behavior.CAPSLE moderated the developmental trend of increasing peer-reported victimization (p < .01), aggression (p < .05), self-reported aggression (p < .05) and aggressive bystanding (p < .05), compared to TAU schools. CAPSLE also moderated a decline in empathy and an increase in the percent of children victimized compared to SPC (p < .01) and TAU conditions (p < .01). Results for self-reported victimization, helpful bystanding, and beliefs in the legitimacy of aggression did not suggest significantly different changes among the study conditions over time. CAPSLE produced a significant decrease in off-task (p < .001) and disruptive classroom behaviors (p < .01), while behavioral change was not observed in SPC and TAU schools. Superiority with respect to TAU for victimization (p < .05), aggression (p < .01), and helpful (p < .05) and aggressive bystanding (p < .01) were maintained in the follow-up year.A teacher-implemented school-wide intervention that does not focus on disturbed children substantially reduced aggression and improved classroom behavior
'On the surface': a qualitative study of GPs' and patients' perspectives on psoriasis
BACKGROUND: Psoriasis is a chronic, inflammatory skin disease affecting approximately 2% of the UK population and is currently incurable. It produces profound effects on psychological wellbeing and social functioning and has significant associated co-morbidities. The majority of patients with psoriasis are managed in primary care, however in-depth patient and GP perspectives about psoriasis management in this setting are absent from the literature. This article reports an in-depth study which compares and contrasts the perspectives of people with psoriasis and of GPs on the challenges of managing psoriasis in primary care. METHODS: In-depth, qualitative semi-structured interviews were conducted with a diverse sample of 29 people with psoriasis and 14 GPs. Interviews were coded using principles of Framework Analysis to enable a comparison of patient and practitioner perspectives on key issues and concepts arising from the data. RESULTS: Patients perceived GPs to be lacking in confidence in the assessment and management of psoriasis and both groups felt lacking in knowledge and understanding about the condition. While practitioners recognised that psoriasis has physical, emotional and social impact, they assumed patients had expertise in the condition and may not address these issues in consultations. This resulted in patient dissatisfaction and sub-optimal assessment of severity and impact of psoriasis by GPs. Patients and GPs recognised that psoriasis was not being managed as a complex long-term condition, however this appeared less problematic for GPs than for patients who desired a shared management with their GP incorporating appropriate monitoring and timely reviews. CONCLUSIONS: The research suggests that current routine practice for psoriasis management in primary care is mismatched with the expressed needs of patients. To address these needs, psoriasis must be recognised as a complex long-term condition involving exacting physical, psychological and social demands, co-morbidity and the development of new treatments.General practitioners need to improve both their knowledge and skills in the assessment and management of psoriasis. This in turn will facilitate management of the condition in partnership with patients. Commissioning multi-disciplinary services, which focus on long-term impacts on wellbeing and quality of life, might address current deficits in care
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