541 research outputs found
Natural Killer cells responsiveness to physical esercise: a brief review
Natural killer cells (NK) are a group of peripheral blood lymphocytes which display cytotoxic ac- tivity against a wide range of tumour cells. They are a consistent part of the inflammatory re- sponse that is activated when either internal or external injuries occur as they are able to syn- thesize perforins. An important role is played by NK cells in the host defence against tumours without expressing any antigen-binding recap- tor in their membrane which, however, distin- guish T and B lymphocytes. NK activity appears early in the immune response, thus providing immediate protection during the time required for the activation and proliferation of cytotoxic T lymphocytes and for their differentiation into functional cells. Even though much research regarding the effects of aerobic training exercise on NK cell numbers and function, there appears to be much controversy regarding its effect. NK cells are rapidly mobilized into circulation in response to acute exercise, most likely by in- creased shear stress and catecholamine-in- duced down-regulation of adhesion molecule expression. However, tissue injury and inflam- mation which often accompanies strenuous ex- ercise have been associated to post-exercise NK cell suppression. Scientific evidence indicates exercise-induced changes in NK cell redistribu- tion and function should be strongly influenced by stress hormones including catecholamines, cortisol and prolactin as well as by soluble me- diators such as cytokines and prostaglandins. The role of exercise therapy in cancer patients and survivors rehabilitation is becoming increasingly important as it is thought to modulate immunity and inflammation. However, more knowledge about the effects of exercise on im-mune function in these patients is needed
Theoretical and experimental analysis of dissipative buckling restrained barces
Buckling restrained braces are passive energy dissipators used for seismic protection of building
frames; such devices consist of slender steel bars connected usually to the frame to be protected
either like conventional (concentric) diagonal braces or like chevron braces. Under horizontal
seismic motions, the interstory drifts generate axial strains in the steel bars beyond their yielding
points; such tension-compression cycles constitute the hysteresis loops. The buckling of the steel
bars (core) is prevented by embedding them in a stockiest encasing; it consists usually of a steel
tube filled with mortar. A crucial issue is to allow sliding between the core and the encasing to
prevent relevant shear stress transfer.
This work aims to contribute to a better understanding of the behavior of buckling restrained
braces; the final objective is to foster its mass use in developing countries (in earthquake prone
regions), particularly for reinforced concrete building frames. The research approach consists of
designing, producing and testing (in Argentina) five reduced scale dissipators (about 400 mm
long) and of taking profit of the gained experience to design, to produce and to test (in Spain) four
full size (near 3000 mm long) prototype devices. All these tests are individual, i.e. no
subassemblies (accounting for the building frames) are considered.
The main conclusion is that it is possible to obtain a reasonably cheap (about 1000 US$ per unit;
this amount corresponds to production in Spain (summer 2006) without optimizing the
fabrication process), efficient, robust, low maintenance and durable prototype device requiring
only a low-tech production process (suitable for developing countries). Moreover, the results
show that the fatigue life of buckling restrained braces, even highly uncertain, can be significantly
bigger than expected (according to some previously published results); it might allow extending
the life of these devices after a number of strong seismic inputs.
A numerical analysis of the buckling behavior of these devices is performed; it allows
formulating some design recommendations. Further research needs are identified
Light Quenched Hadron Spectrum and Decay Constants on different Lattices
We present a study of (quenched) lattice configurations from
the APE collaboration, for using both the Wilson and the
SW-Clover fermion action. We determine the light hadronic spectrum and meson
decay constants. We extract the inverse lattice spacing using data at the
simulated values of the quark mass. We find an agreement with the experimental
data of for mesonic masses and for baryonic masses and
pseudoscalar decay constants. A larger deviation is present for the vector
decay constants.Comment: 3 pages, Talk presented at LATTICE96(spectrum
Theoretical and experimental analysis of dissipative buckling restrained braces
Buckling restrained braces are passive energy dissipators used for seismic protection of building frames; such devices consist of slender steel bars connected usually to the frame to be protected either like conventional (concentric) diagonal braces or like chevron braces. Under horizontal seismic motions, the interstory drifts generate axial strains in the steel bars beyond their yielding points, such tension-compresssion cycles constitute the hysteresis loops. Thebuckling of the steel bars (core) is prevented by embedding them in a stockiest encasing; it consists usually of a steel tube filled with mortar. A crucial issue is to allow sliding between the core and the encasing to prevent relevant shear stress transfer. This work aims to contribute to a better understanding of the behavior of buckling restrained braces, the final objective is to foster its mass use in developing countries (in earthquake prone regions), particulary for reinforced concrete building frames. The research approach consists of designing, producing and testing (in Argentina) five reduced scale dissipators (about 400 mm long) and of taking profit of the gained experience to design, to produce and to test (in Spain) four full size (near 3000 mm long) prototype devices. All these tests are a individual, i.e. no subassemblies (accounting for the building frames) are considered. The main conclusion is that it is possible to obtain a reasonably cheap (about 1000 US$ per unit; this amount corresponds to production in Spain (summer 2006) without optimizing the fabrication process), efficient, robust, low maintenance and durable prototype device requiring only a low-tech production process (suitable for developing countries). Moreover, the results show that the fatigue life of buckling restrained braces, even highly uncertain, can be significantly bigger than expected (according to some previously published results); it might allow extending the life of these devices after a number of strong seismic inputs. A numerical analysis of the buckling behavior of these devices is performed; it allows formulating some design recommendations. Further research needs are identified.Postprint (published version
RESULTS FOR THE B-MESON DECAY CONSTANT FROM THE APE COLLABORATION
The decay constant for the B-meson in the static limit is calculated using
the Wilson and clover actions at various lattice spacings. We show that both
the contamination of our results by excited states and the effects finite
lattice spacing are at most the order of the statistical uncertainties. A
comparison is made of our results and those obtained in other studies. Values
for and are also given.Comment: Contribution to Lattice'94, 3 pages PostScript, uuencoded compresse
Modulation of cardiac contractility by muscle metaboreflex following efforts of different intensities in humans.
Chiral behaviour of the lattice -parameter with the Wilson and Clover Actions at
We present results for the kaon -parameter from a sample of
configurations using the Wilson action and configurations using the
SW-Clover action, on a lattice at . We compare
results obtained by renormalizing the relevant operator with different
``boosted" values of the strong coupling constant . In the case of
the SW-Clover action, we also use the operator renormalized non-perturbatively.
In the Wilson case, we observe a strong dependence of on the prescription
adopted for , contrary to the results of the Clover case which are
almost unaffected by the choice of the coupling. We also find that the matrix
element of the operator renormalized non-perturbatively has a better chiral
behaviour. This gives us our best estimate of the renormalization group
invariant -parameter, .Comment: LaTeX, 17 pages, 3 postscript figures uuencode
Covid-19 vaccines in children with cow’s milk and food allergies
The COVID-19 pandemic is the most challenging global health crisis of our times. Vaccination against COVID-19 plays a key role to control the current pandemic situation. The risk of allergic reactions to new COVID-19 vaccines is low. However, there is a debate on the safety in allergic patients following post marketing findings by different agencies. Our aim is to understand from current experiences whether children with cow’s milk or food allergy are at higher risk than a general population for allergic reactions to COVID-19 vaccines. Current data indicate that patients with a history of allergy to cow’s milk or other foods, even if severe, should receive COVID-19 vaccine in a setting with availability of treatments for anaphylactic reactions and under medical supervision. Recipients should be discharged after a protracted observation period of 30 min if no reaction developed
Respiratory muscle training in patients recovering recent open cardio-thoracic surgery: a randomized-controlled trial.
Objectives- To evaluate the clinical efficacy and feasibility of an expiratory muscle training (EMT) device (Respilift™) applied to patients recovering from recent open cardio-thoracic surgery (CTS).
Design- Prospective, double-blind, 14-day randomised-controlled trial.
Participants and setting- 60 inpatients recovering from recent CTS and early admitted to a pulmonary rehabilitation program.
Interventions- Chest physiotherapy plus EMT with a resistive load of 30 cm H2O for active group and chest physiotherapy plus EMT with a sham load for control group.
Measures- Changes in maximal expiratory pressure (MEP) was considered as primary outcome, while maximal inspiratory pressures (MIP), dynamic and static lung volumes, oxygenation, perceived symptoms of dyspnoea, thoracic pain and well being (evaluated by visual analogic scale-VAS) and general health status were considered secondary outcomes.
Results- All outcomes recorded showed significant improvements in both groups; however, the change of MEP (+34.2 mmHg, p<0.001 and +26.1%, p<0.001 for absolute and % of predicted, respectively) was significantly higher in Active group. Also VAS-dyspnoea improved faster and more significantly (p<0.05) at day 12 and 14 in Active group when compared with Control. The drop out rate was 6%, without differences between groups.
Conclusions- In patients recovering from recent CTS specific EMT by Respilift™ is feasible and effective
Effects of a walking aid in COPD patients receiving oxygen therapy
STUDY OBJECTIVES: To elucidate whether a simple walking aid may improve physical performance in COPD patients with chronic respiratory insufficiency who usually carry their own heavy oxygen canister. DESIGN: Randomized crossover trial. SETTING: Physiopathology laboratory of three rehabilitation centers. PATIENTS AND INTERVENTIONS: We studied 60 stable COPD patients (mean age, 70.6 +/- 7.9 years; FEV(1), 44.8 +/- 14.3% of predicted [+/- SD]) with chronic respiratory insufficiency who randomly performed, on 2 consecutive days, a standardized 6-min walking test using two different modalities: a full-weight oxygen canister transported using a small wheeled cart and pulled by the patient (Aid modality) or full-weight oxygen canister carried on the patient's shoulder (No-Aid modality). MEASUREMENTS AND RESULTS: The distance walked, peak effort dyspnea, and leg fatigue scores as primary outcomes, and other cardiorespiratory parameters as secondary outcomes were recorded during both tests. A significant difference (p < 0.05) between the two tests occurred for all the measured outcomes in favor of the Aid modality. Most importantly, significant changes for distance (+ 43 m, p < 0.001), peak effort dyspnea (- 2.0 points, p < 0.001), leg fatigue (- 1.4 points, p < 0.001), as well as for mean and nadir oxygen saturation and heart rate with the Aid modality (but not with the No-Aid modality) were recorded in the subgroup of patients walking < 300 m at baseline. CONCLUSIONS: This study suggests that a simple walking aid may be helpful in COPD patients receiving long-term oxygen therapy, particularly in those with lower residual exercise capacity
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