3,940 research outputs found
Mindfulness-Based Cognitive Therapy: Further Issues in Current Evidence and Future Research
The authors respond to the article by H. F. Coelho, P. H. Canter, and E. Ernst (2007)A. T. Beck, C. H. Ward, M. Mendelson, J. Mock, & J. Erbaugh, 1961) after treatment
‘Fit for surgery’:the relationship between cardiorespiratory fitness and postoperative outcomes
NEW FINDINGS: What is the topic of this review? The relationships and physiological mechanisms underlying the clinical benefits of cardiorespiratory fitness (CRF) in patients undergoing major intra‐abdominal surgery. What advances does it highlight? Elevated CRF reduces postoperative morbidity/mortality, thus highlighting the importance of CRF as an independent risk factor. The vascular protection afforded by exercise prehabilitation can further improve surgical risk stratification and postoperative outcomes. ABSTRACT: Surgery accounts for 7.7% of all deaths globally and the number of procedures is increasing annually. A patient's ‘fitness for surgery’ describes the ability to tolerate a physiological insult, fundamental to risk assessment and care planning. We have evolved as obligate aerobes that rely on oxygen (O(2)). Systemic O(2) consumption can be measured via cardiopulmonary exercise testing (CPET) providing objective metrics of cardiorespiratory fitness (CRF). Impaired CRF is an independent risk factor for mortality and morbidity. The perioperative period is associated with increased O(2) demand, which if not met leads to O(2) deficit, the magnitude and duration of which dictates organ failure and ultimately death. CRF is by far the greatest modifiable risk factor, and optimal exercise interventions are currently under investigation in patient prehabilitation programmes. However, current practice demonstrates potential for up to 60% of patients, who undergo preoperative CPET, to have their fitness incorrectly stratified. To optimise this work we must improve the detection of CRF and reduce potential for interpretive error that may misinform risk classification and subsequent patient care, better quantify risk by expressing the power of CRF to predict mortality and morbidity compared to traditional cardiovascular risk factors, and improve patient interventions with the capacity to further enhance vascular adaptation. Thus, a better understanding of CRF, used to determine fitness for surgery, will enable both clinicians and exercise physiologists to further refine patient care and management to improve survival
Fidelity and plausibility of bimanual interaction in mixed reality
When human actors interact with virtual objects the result is often not convincing to a third party viewer, due to incongruities between the actor and object positions. In this study we aim to quantify the magnitude and impact of the errors that occur in a bimanual interaction, that is when an actor attempts to move a virtual object by holding it between both hands. A three stage framework is presented which firstly captures the magnitude of these interaction errors, then quantifies their effect on the relevant third party audience, and thirdly assesses methods to mitigate the impact of the errors. Findings from this work show that the degree of error was dependent on the size of the virtual object and also on the axis of the hand placement with respect to the axis of the interactive motion. In addition, actor hand placement outside and away from the object surface was found to affect the visual plausibility considerably more than when the actor's hands were within the object boundaries. Finally, a method for automatic adaptation of the object size to match the distance between the actor's hands gave a significant improvement in the viewers' assessment of the scene plausibility. © 1995-2012 IEEE
SenseBack - An implantable system for bidirectional neural interfacing
Chronic in-vivo neurophysiology experiments require highly miniaturized, remotely powered multi-channel neural interfaces which are currently lacking in power or flexibility post implantation. In this article, to resolve this problem we present the SenseBack system, a post-implantation reprogrammable wireless 32-channel bidirectional neural interfacing that can enable chronic peripheral electrophysiology experiments in freely behaving small animals. The large number of channels for a peripheral neural interface, coupled with fully implantable hardware and complete software flexibility enable complex in-vivo studies where the system can adapt to evolving study needs as they arise. In complementary ex-vivo and in-vivo preparations, we demonstrate that this system can record neural signals and perform high-voltage, bipolar stimulation on any channel. In addition, we demonstrate transcutaneous power delivery and Bluetooth 5 data communication with a PC. The SenseBack system is capable of stimulation on any channel with ±20 V of compliance and up to 315 μA of current, and highly configurable recording with per-channel adjustable gain and filtering with 8 sets of 10-bit ADCs to sample data at 20 kHz for each channel. To the best of our knowledge this is the first such implantable research platform offering this level of performance and flexibility post-implantation (including complete reprogramming even after encapsulation) for small animal electrophysiology. Here we present initial acute trials, demonstrations and progress towards a system that we expect to enable a wide range of electrophysiology experiments in freely behaving animals
High Resolution Infrared Imaging and Spectroscopy of the Pistol Nebula: Evidence for Ejection
We present new NICMOS/HST infrared images and CGS4/UKIRT Br-alpha (4.05 um)
spectroscopy of the Pistol Star and its associated nebula, finding strong
evidence to support the hypothesis that the Pistol Nebula was ejected from the
Pistol Star. The Pa-alpha NICMOS image shows that the nebula completely
surrounds the Pistol Star, although the line intensity is much stronger on its
northern and western edges. The Br-alpha spectra show the classical ring-like
signature of quasi-spherical expansion, with weak blueshifted emission (V_max
approx -60 km/s) and strong redshifted emission (V_max approx +10 km/s), where
the velocities are with respect to the velocity of the Pistol Star; further,
the redshifted emission appears to be "flattened" in the position-velocity
diagram. These data suggest that the nebula was ejected from the star several
thousand years ago, with a velocity between the current terminal velocity of
the stellar wind (95 km/s) and the present expansion velocity of gas in the
outer shell of the nebula (60 km/s). The Pa-alpha image reveals several
emission-line stars in the region, including two newly-identified emission-line
stars north of the Pistol Star with spectral types earlier than WC8 (T_eff >
50,000 K). The presence of these stars, the morphology of the Pa-alpha
emission, and the velocity field in the gas suggest that the side of the nebula
furthest from us is approaching, and being ionized by, the hot stars of the
Quintuplet, and that the highest velocity redshifted gas has been decelerated
by winds from the Quintuplet stars. We also discuss the possibility that the
nebular gas might be magnetically confined by the ambient magnetic field
delineated by the nearby nonthermal filaments.Comment: Figure 1 is included as a JPG file. Figure 1 and 2 also available at
ftp://quintup.astro.ucla.edu/pistol2
Interannual variability of photosynthesis across Africa and its attribution
Africa is thought to be a large source of interannual variability in the global carbon cycle, only vaguely attributed to climate fluctuations. This study uses a biophysical model, Simple Biosphere, to examine in detail what specific factors, physiological (acute stress from low soil water, temperature, or low humidity) and biophysical (low vegetation radiation use), are responsible for spatiotemporal patterns of photosynthesis across the African continent during the period 1982-2003. Acute soil water stress emerges as the primary factor driving interannual variability of photosynthesis for most of Africa. Southern savannas and woodlands are a particular hot spot of interannual variability in photosynthesis, owing to high rainfall variability and photosynthetic potential but intermediate annual rainfall. Surprisingly low interannual variability of photosynthesis in much of the Sudano-Sahelian zone derives from relatively low vegetation cover, pronounced humidity stress, and somewhat lower rainfall variability, whereas perennially wet conditions diminish interannual variability in photosynthesis across much of the Congo Basin and coastal West Africa. Though not of focus here, the coefficient of variation in photosynthesis is notably high in drylands and desert margins (i.e., Sahel, Greater Horn, Namib, and Kalahari) having implications for supply of food and fiber. These findings emphasize that when considering impacts of climate change and land surface feedbacks to the atmosphere, it is important to recognize how vegetation, climate, and soil characteristics may conspire to filter or dampen ecosystem responses to hydroclimatic variability. Copyright 2008 by the American Geophysical Union
Trauma Immediately Preceding REM-Behavior Disorder:A Valuable Prognostic Marker?
Background: The definition of rapid eye movement (REM) sleep behavior disorder (RBD) has varied over the years. Rapid eye movement sleep behavior disorder can be considered isolated or idiopathic or can occur in the context of other disorders, including trauma-associated sleep disorder (TSD) and overlap parasomnia. However, whether trauma in RBD carries any prognostic specificity is currently unknown.
Study Objectives: To test the hypothesis that RBD secondary to trauma is less likely to result in the development of neurodegeneration compared to idiopathic RBD (iRBD) without trauma in the general population.
Methods: A retrospective cohort study of 122 consecutive RBD patients (103 males) at two tertiary sleep clinics in Europe between 2005 and 2020 was studied. Patients were diagnosed as having iRBD by video polysomnography (vPSG) and had a semi-structured interview at presentation, including specifically eliciting any history of trauma. Patients with secondary RBD to recognized causes were excluded from the study. Patients with iRBD were categorized into three groups according to reported trauma history: (1) No history of trauma, (2) traumatic experience at least 12 months prior to RBD symptom onset, and (3) traumatic experience within 12 months of RBD symptom onset. Idiopathic RBD duration was defined as the interval between estimated onset of RBD symptoms and last hospital visit or death. Follow-up duration was defined as the interval between iRBD diagnosis and last hospital visit or death.
Results: In a follow-up period of up to 18 years, no patient who experienced trauma within 12 months preceding their iRBD diagnosis received a diagnosis of a neurodegenerative disorder (n = 35), whereas 38% of patients without trauma within the 12 months of symptom onset developed a neurodegenerative illness. These patients were also significantly more likely to have a family history of α-synucleinopathy or tauopathy.
Conclusions: The development of RBD within 12 months of experiencing a traumatic life event, indistinguishable clinically from iRBD, did not lead to phenoconversion to a neurodegenerative disorder even after 18 years (mean follow up 6 years). We suggest that a sub-type of RBD be established and classified as secondary RBD due to trauma. Additionally, we advocate that a thorough psychological and trauma history be undertaken in all patients presenting with dream enactment behaviors (DEB)
Barriers and facilitators to change in the organisation and delivery of endoscopy services in England and Wales: a focus group study
Objective: Explore professional views of changes to gastroenterology service organisation and delivery and barriers and facilitators impacting on change. The work was undertaken as part of an evaluation in endoscopy service provision catalysed by the Modernising Endoscopy Services Programme of the Modernisation Agency. Design: Focus groups followed by analysis and group-working activities identifying key themes. Setting: English and Welsh secondary care gastroenterology units. Participants: 20 professionals working in gastroenterology in England and Wales. Medical, surgical and nursing specialists including endoscopy nurses. Opportunistic sampling to include senior people in leadership and management roles who were directly involved in service modernisation, excluding those involved in the Modernisation Endoscopy Services Programme. Results: Four 1.5 h focus groups took place in 2007. Summative and thematic analyses captured essential aspects of text and achieved consensus on key themes. 4 themes were revealed: 'loss of personal autonomy and erosion of professionalism', 'lack of senior management understanding', 'barriers and facilitators to change' and 'differences between English and Welsh units'. Themes indicated that low staff morale, lack of funding and senior management support were barriers to effective change. Limitations to the study include the disproportionately low number of focus group attendees from English units and the time delay in reporting these findings. Conclusions: Despite ambitions to implement change, ineffective management support continued to hamper modernisation of service organisation and delivery. While the National Health Service Modernisation Agency Modernising Endoscopy Services Programme acted as a catalyst for change, affecting the way staff work, communicate and think, it was not effective in heralding change itself. However, gastroenterologists were keen to consider the potential for change and future service modernisation. The methodological framework of innovative qualitative enquiry offers comprehensive and rigorous enhancement of quantitative studies, including randomised trials, when a mixed methods approach is needed.7 page(s
Retroperitoneal Compared to Transperitoneal Approach for Open Abdominal Aortic Aneurysm Repair Is Associated with Reduced Systemic Inflammation and Postoperative Morbidity
Background In the United Kingdom, the most common surgical approach for repair of open abdominal aortic aneurysms (AAAs) is transperitoneal (TP). However, retroperitoneal (RP) approach is favored in those with more complex vascular anatomy often requiring a cross-clamp on the aorta superior to the renal arteries. This study compared these approaches in patients matched on all major demographic, comorbid, anatomic, and physiological variables. Methods Fifty-seven patients (TP: n = 24; RP: n = 33) unsuitable for endovascular aneurysm repair underwent preoperative cardiopulmonary exercise testing prior to open AAA repair. The surgical approach undertaken was dictated by individual surgeon preference. Postoperative mortality, complications, and length of hospital stay (LoS) were recorded. Patients were further stratified according to infrarenal (IR) or suprarenal/supraceliac (SR/SC) surgical clamping. Systemic inflammation (C-reactive protein) and renal function (serum creatinine and estimated glomerular filtration rate) were recorded. Results Twenty-three (96%) of TP patients only required an IR clamp compared with 12 (36%) in the RP group. Postoperative systemic inflammation was lower in RP patients ( p = 0.002 vs. TP) and fewer reported pulmonary/gastrointestinal complications whereas renal impairment was more marked in those receiving SR/SC clamps ( p < 0.001 vs. IR clamp). RP patients were defined by lower LoS ( p = 0.001), while mid-/long-term mortality was low/comparable with TP, resulting in considerable cost savings. Conclusion Despite the demands of more complicated vascular anatomy, the clinical and economic benefits highlighted by these findings justify the more routine adoption of the RP approach for complex AAA repair
Leiomyosarcoma of the inferior vena cava: Clinical experience with four cases
BACKGROUND: Leiomyosarcoma of the inferior vena cava is a rare tumor that presents in an insidious manner with non-specific symptoms. Given its rarity, there are no consensus guidelines to its management. The aim of this study was to report the clinical experience in the management of patients presenting to our institution during a 12 year period. PATIENTS AND METHODS: Four patients with leiomyosarcomas of the inferior vena cava were managed at our institution during the period reviewed. Patient details were identified through a search of the pathology department computerized database, and case notes were retrospectively reviewed to obtain details of presentation and management. RESULTS: There were 3 females and 1 male with a mean age of 59 years. All tumors were identified within 2 months of first symptoms. Three of the 4 had localized tumors whilst 1 patient had lung metastases at presentation. The three patients with resectable tumors underwent radical surgical excision of the tumor, and two patients had postoperative radiotherapy. One patient died of recurrence at 7 months, and another at 30 months. The third patient is currently well and disease free at 16 months. The fourth patient with metastatic disease was treated with chemotherapy alone and survived 36 months. CONCLUSION: Leiomyosarcoma of the inferior vena cava is an uncommon tumor that presents with non-specific symptoms. At the time of presentation, tumors are usually large and resection is challenging but probably offers the best opportunity for long-term survival
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