99 research outputs found
Exploration of Resonant Continuum and Giant Resonance in the Relativistic Approach
Single-particle resonant-states in the continuum are determined by solving
scattering states of the Dirac equation with proper asymptotic conditions in
the relativistic mean field theory (RMF). The regular and irregular solutions
of the Dirac equation at a large radius where the nuclear potentials vanish are
relativistic Coulomb wave functions, which are calculated numerically.
Energies, widths and wave functions of single-particle resonance states in the
continuum for ^{120}Sn are studied in the RMF with the parameter set of NL3.
The isoscalar giant octupole resonance of ^{120}Sn is investigated in a fully
consistent relativistic random phase approximation. Comparing the results with
including full continuum states and only those single-particle resonances we
find that the contributions from those resonant-states dominate in the nuclear
giant resonant processes.Comment: 16 pages, 2 figure
Musculoskeletal symptoms of the upper extremities and the neck: A cross-sectional study on prevalence and symptom-predicting factors at visual display terminal (VDT) workstations
<p>Abstract</p> <p>Background</p> <p>The aim of this study was to determine the prevalence and the predictors of musculoskeletal symptoms in the upper extremities and neck at visual display terminal (VDT) workstations.</p> <p>Methods</p> <p>In a cross-sectional study 1,065 employees working at VDT > 1 h/d completed a standardised questionnaire. Workstation conditions were documented in a standardised checklist, and a subgroup of 82 employees underwent a physical examination.</p> <p>Results</p> <p>Using the Nordic Questionnaire, the 12-month prevalence of symptoms of the neck, shoulder region, hand/wrist, or elbow/lower arm was 55%, 38%, 21%, and 15% respectively. The duration of VDT work had a significant impact on the frequency of neck symptoms in employees performing such work > 6 h/d.</p> <p>Conclusion</p> <p>With regard to musculoskeletal symptoms of the upper extremities, preventive measures at VDT workstations should be focused on neck and shoulder symptoms (e.g. ergonomic measures, breaks to avoid sitting over long periods).</p
Biomagnifcation and body distribution of ivermectin in dung beetles
We thank the staf of DoΓ±ana Biological Reserve (DBR-ICTS), DoΓ±ana National Park, and Los Alcornocales
Natural Park, especially D. Paz, F. IbÑñez, P. Bayón, M. Malla and D. Ruiz for logistic facilities for the field
work and permissions (2019107300000904/IRM/MDCG/mes) to collect cattle dung and dung beetles. We
are grateful to J. Castro and A. RascΓ³n for technical assistance. We also thank A. V. GimΓ©nez-GΓ³mez for her
technical assistance in the laboratory work. We thank also F.-T Krell and the two anonymous reviewers for their
constructive comments. Financial support was provided by the project CGL2015-68207-R of the SecretarΓa de
Estado de InvestigaciΓ³nβMinisterio de EconomΓa y Competitividad.A terrestrial test system to investigate the biomagnifcation potential and tissue-specifc distribution
of ivermectin, a widely used parasiticide, in the non-target dung beetle Thorectes lusitanicus (Jekel)
was developed and validated. Biomagnifcation kinetics of ivermectin in T. lusitanicus was investigated
by following uptake, elimination, and distribution of the compound in dung beetles feeding on
contaminated faeces. Results showed that ivermectin was biomagnifed in adults of T. lusitanicus
when exposed to non-lethal doses via food uptake. Ivermectin was quickly transferred from the gut to
the haemolymph, generating a biomagnifcation factor (BMFk) three times higher in the haemolymph
than in the gut after an uptake period of 12 days. The fat body appeared to exert a major role on
the biomagnifcation of ivermectin in the insect body, showing a BMFk 1.6 times higher than in the
haemolymph. The results of this study highlight that the biomagnifcation of ivermectin should be
investigated from a global dung-based food web perspective and that the use of these antiparasitic
substances should be monitored and controlled on a precautionary basis. Thus, we suggest that an
additional efort be made in the development of standardised regulatory recommendations to guide
biomagnifcation studies in terrestrial organisms, but also that it is necessary to adapt existing methods
to assess the efects of such veterinary medical products
Development of an in-vivo active reversible butyrylcholinesterase inhibitor
Alzheimerβs disease (AD) is characterized by severe basal forebrain cholinergic deficit, which results in progressive and chronic deterioration of memory and cognitive functions. Similar to acetylcholinesterase, butyrylcholinesterase (BChE) contributes to the termination of cholinergic neurotransmission. Its enzymatic activity increases with the disease progression, thus classifying BChE as a viable therapeutic target in advanced AD. Potent, selective and reversible human BChE inhibitors were developed. The solved crystal structure of human BChE in complex with the most potent inhibitor reveals its binding mode and provides the molecular basis of its low nanomolar potency. Additionally, this compound is noncytotoxic and has neuroprotective properties. Furthermore, this inhibitor moderately crosses the blood-brain barrier and improves memory, cognitive functions and learning abilities of mice in a model of the cholinergic deficit that characterizes AD, without producing acute cholinergic adverse effects. Our study provides an advanced lead compound for developing drugs for alleviating symptoms caused by cholinergic hypofunction in advanced AD
Computer work and musculoskeletal disorders of the neck and upper extremity: A systematic review
<p>Abstract</p> <p>Background</p> <p>This review examines the evidence for an association between computer work and neck and upper extremity disorders (except carpal tunnel syndrome).</p> <p>Methods</p> <p>A systematic critical review of studies of computer work and musculoskeletal disorders verified by a physical examination was performed.</p> <p>Results</p> <p>A total of 22 studies (26 articles) fulfilled the inclusion criteria. Results show limited evidence for a causal relationship between computer work per se, computer mouse and keyboard time related to a diagnosis of wrist tendonitis, and for an association between computer mouse time and forearm disorders. Limited evidence was also found for a causal relationship between computer work per se and computer mouse time related to tension neck syndrome, but the evidence for keyboard time was insufficient. Insufficient evidence was found for an association between other musculoskeletal diagnoses of the neck and upper extremities, including shoulder tendonitis and epicondylitis, and any aspect of computer work.</p> <p>Conclusions</p> <p>There is limited epidemiological evidence for an association between aspects of computer work and some of the clinical diagnoses studied. None of the evidence was considered as moderate or strong and there is a need for more and better documentation.</p
Sarcopenia: etiology, clinical consequences, intervention, and assessment
The aging process is associated with loss of muscle mass and strength and decline in physical functioning. The term sarcopenia is primarily defined as low level of muscle mass resulting from age-related muscle loss, but its definition is often broadened to include the underlying cellular processes involved in skeletal muscle loss as well as their clinical manifestations. The underlying cellular changes involve weakening of factors promoting muscle anabolism and increased expression of inflammatory factors and other agents which contribute to skeletal muscle catabolism. At the cellular level, these molecular processes are manifested in a loss of muscle fiber cross-sectional area, loss of innervation, and adaptive changes in the proportions of slow and fast motor units in muscle tissue. Ultimately, these alterations translate to bulk changes in muscle mass, strength, and function which lead to reduced physical performance, disability, increased risk of fall-related injury, and, often, frailty. In this review, we summarize current understanding of the mechanisms underlying sarcopenia and age-related changes in muscle tissue morphology and function. We also discuss the resulting long-term outcomes in terms of loss of function, which causes increased risk of musculoskeletal injuries and other morbidities, leading to frailty and loss of independence
- β¦