2,810 research outputs found
Sediments: sink, archive, and source of contaminants
Se ha publicado una corrección de este artículo el 03 February 2023 ; DOI: 10.1007/s11356-023-25555-y
Publicado en: Environmental Science and Pollution Research, Vol. 30, nº 12, March 2023, pp. 35514Sediments are sources and sinks of contaminants and play an important role in mediating pollutants across environmental compartments of terrestrial and aquatic ecosystems. In surface waters (lakes, slowly flowing or dammed rivers, estuaries, oceans), organic and inorganic contaminants are either dissolved or sorbed to suspended matter and sediment particles according to their chemical properties. In the case of strong sorption, settling of suspended particles and sediment formation scavenge contaminants out of the water phase, resulting in the accumulation of contaminants in the beds of rivers and lakes.5 página
Microstructural And Mechanical Study of The Al-20Sn (MASS%) Alloy Processed By Equal-Channel Angular Pressing By Route C
In this work, the feasibility of an Al–20Sn (mass%) alloy to improve its mechanical properties through the Equal Channel Angular Pressing (ECAP) process is presented and discussed. Al–20Sn (mass%) alloy samples with a square section of 16 × 16 mm and a length of 100 mm were subjected to the ECAP process through route C (i.e., rotation of 180 degrees between each pass). The characterization of the samples was carried out using X-ray diffraction and the sin^2(ψ) method for residual stresses. Scanning Electron Microscopy (SEM) was used to analyze the morphology and grain size. Vickers microhardness was carried out to analyze the homogeneity of the states of deformation and tensile testing to evaluate the yield strength, ultimate tensile strength and elongation. The results showed that the residual stresses were relatively low, confirming the effect of Sn as stress reliever. The grain size was refined to a sub-micron scale and a ribbon-like morphology was observed. The microhardness values of the severely deformed samples showed a significant increase when compared to the as-cast sample. The tensile tests showed an increase in the yield strength after the first pass, that doubled the yield strength of the as cast sample. A marginal increase in the yield strength after the fifth pass was observed; whilst the ductility remained very similar from 1 to 5 passes.In this work, the feasibility of an Al–20Sn (mass%) alloy to improve its mechanical properties through the Equal Channel Angular Pressing (ECAP) process is presented and discussed. Al–20Sn (mass%) alloy samples with a square section of 16 × 16 mm and a length of 100 mm were subjected to the ECAP process through route C (i.e., rotation of 180 degrees between each pass). The characterization of the samples was carried out using X-ray diffraction and the sin^2(ψ) method for residual stresses. Scanning Electron Microscopy (SEM) was used to analyze the morphology and grain size. Vickers microhardness was carried out to analyze the homogeneity of the states of deformation and tensile testing to evaluate the yield strength, ultimate tensile strength and elongation. The results showed that the residual stresses were relatively low, confirming the effect of Sn as stress reliever. The grain size was refined to a sub-micron scale and a ribbon-like morphology was observed. The microhardness values of the severely deformed samples showed a significant increase when compared to the as-cast sample. The tensile tests showed an increase in the yield strength after the first pass, that doubled the yield strength of the as cast sample. A marginal increase in the yield strength after the fifth pass was observed; whilst the ductility remained very similar from 1 to 5 passes
Monitoring of the arterial pressure in effort. dominant, not dominant arm or both?
Objetivo: evaluar la diferencia de los valores de Presión arterial (PA) entre ambos brazos, medida simultáneamente, durante una prueba de esfuerzo.
Diseño del estudio: estudio transversal. Series de casos. Nivel de evidencia: 3
Material y Métodos: La población se compone de 225 deportistas sanos que realizaron una prueba de esfuerzo en nuestro centro. 128 hombres y 97 mujeres. Edad: 17± 5,5 años.
Resultados: La PA tanto sistólica como diastólica no difiere significativamente entre ambos miembros superiores. No obstante, hemos encontrado casos de variabilidad individual donde la PA predomina en un brazo durante el reposo y en el otro brazo durante el máximo esfuerzo. Los valores de TA son independientes del brazo dominante.
Conclusiones: La posibilidad que el brazo donde predomina la PA de Reposo no coincida durante el máximo esfuerzo, hace necesario, en nuestra opinión, que se mida la PA en ambos miembros superiores durante la prueba de esfuerzoObjective: To evaluate different blood pressure readings between both arms.
Study design: cross-sectional study. Case series. Level of evidence: 3.
Methods: a population of 225 healthy athletes underwent stress tests in our center: 128 males and 97 females. Age range: 17 +/- 5.5 years.
Results: no significant differences in systolic or diastolic blood pressure readings were found between the right or left arm. We did, however, find cases where blood pressure is higher in one arm while resting and in the other arm during maximal exercise. Blood pressure readings were not associated with the dominant arm.
Conclusions: The possibility that the arm in which there is a predominant rest blood pressure does not coincide during maximum stress, makes it necessary, according to our judgment, to measure blood pressure in both upper limbs during stress test
Prediction of clinical toxicity in locally advanced head and neck cancer patients by radio-induced apoptosis in peripheral blood lymphocytes (PBLs)
Head and neck cancer is treated mainly by surgery and radiotherapy. Normal tissue toxicity due to x-ray exposure is a limiting factor for treatment success. Many efforts have been employed to develop predictive tests applied to clinical practice. Determination of lymphocyte radio-sensitivity by radio-induced apoptosis arises as a possible method to predict tissue toxicity due to radiotherapy. The aim of the present study was to analyze radio-induced apoptosis of peripheral blood lymphocytes in head and neck cancer patients and to explore their role in predicting radiation induced toxicity. Seventy nine consecutive patients suffering from head and neck cancer, diagnosed and treated in our institution, were included in the study. Toxicity was evaluated using the Radiation Therapy Oncology Group scale. Peripheral blood lymphocytes were isolated and irradiated at 0, 1, 2 and 8 Gy during 24 hours. Apoptosis was measured by flow cytometry using annexin V/propidium iodide. Lymphocytes were marked with CD45 APC-conjugated monoclonal antibody. Radiation-induced apoptosis increased in order to radiation dose and fitted to a semi logarithmic model defined by two constants: α and β. α, as the origin of the curve in the Y axis determining the percentage of spontaneous cell death, and β, as the slope of the curve determining the percentage of cell death induced at a determined radiation dose, were obtained. β value was statistically associated to normal tissue toxicity in terms of severe xerostomia, as higher levels of apoptosis were observed in patients with low toxicity (p = 0.035; Exp(B) 0.224, I.C.95% (0.060-0.904)). These data agree with our previous results and suggest that it is possible to estimate the radiosensitivity of peripheral blood lymphocytes from patients determining the radiation induced apoptosis with annexin V/propidium iodide staining. β values observed define an individual radiosensitivity profile that could predict late toxicity due to radiotherapy in locally advanced head and neck cancer patients. Anyhow, prospective studies with different cancer types and higher number of patients are needed to validate these results
Prediction of clinical toxicity in localized cervical carcinoma by radio-induced apoptosis study in peripheral blood lymphocytes (PBLs)
<p>Abstract</p> <p>Background</p> <p>Cervical cancer is treated mainly by surgery and radiotherapy. Toxicity due to radiation is a limiting factor for treatment success. Determination of lymphocyte radiosensitivity by radio-induced apoptosis arises as a possible method for predictive test development. The aim of this study was to analyze radio-induced apoptosis of peripheral blood lymphocytes.</p> <p>Methods</p> <p>Ninety four consecutive patients suffering from cervical carcinoma, diagnosed and treated in our institution, and four healthy controls were included in the study. Toxicity was evaluated using the Lent-Soma scale. Peripheral blood lymphocytes were isolated and irradiated at 0, 1, 2 and 8 Gy during 24, 48 and 72 hours. Apoptosis was measured by flow cytometry using annexin V/propidium iodide to determine early and late apoptosis. Lymphocytes were marked with CD45 APC-conjugated monoclonal antibody.</p> <p>Results</p> <p>Radiation-induced apoptosis (RIA) increased with radiation dose and time of incubation. Data strongly fitted to a semi logarithmic model as follows: RIA = βln(Gy) + α. This mathematical model was defined by two constants: α, is the origin of the curve in the Y axis and determines the percentage of spontaneous cell death and β, is the slope of the curve and determines the percentage of cell death induced at a determined radiation dose (β = ΔRIA/Δln(Gy)). Higher β values (increased rate of RIA at given radiation doses) were observed in patients with low sexual toxicity (Exp(B) = 0.83, C.I. 95% (0.73-0.95), p = 0.007; Exp(B) = 0.88, C.I. 95% (0.82-0.94), p = 0.001; Exp(B) = 0.93, C.I. 95% (0.88-0.99), p = 0.026 for 24, 48 and 72 hours respectively). This relation was also found with rectal (Exp(B) = 0.89, C.I. 95% (0.81-0.98), p = 0.026; Exp(B) = 0.95, C.I. 95% (0.91-0.98), p = 0.013 for 48 and 72 hours respectively) and urinary (Exp(B) = 0.83, C.I. 95% (0.71-0.97), p = 0.021 for 24 hours) toxicity.</p> <p>Conclusion</p> <p>Radiation induced apoptosis at different time points and radiation doses fitted to a semi logarithmic model defined by a mathematical equation that gives an individual value of radiosensitivity and could predict late toxicity due to radiotherapy. Other prospective studies with higher number of patients are needed to validate these results.</p
Radiation induced apoptosis and initial DNA damage are inversely related in locally advanced breast cancer patients
<p>Abstract</p> <p>Background</p> <p>DNA-damage assays, quantifying the initial number of DNA double-strand breaks induced by radiation, have been proposed as a predictive test for radiation-induced toxicity. Determination of radiation-induced apoptosis in peripheral blood lymphocytes by flow cytometry analysis has also been proposed as an approach for predicting normal tissue responses following radiotherapy. The aim of the present study was to explore the association between initial DNA damage, estimated by the number of double-strand breaks induced by a given radiation dose, and the radio-induced apoptosis rates observed.</p> <p>Methods</p> <p>Peripheral blood lymphocytes were taken from 26 consecutive patients with locally advanced breast carcinoma. Radiosensitivity of lymphocytes was quantified as the initial number of DNA double-strand breaks induced per Gy and per DNA unit (200 Mbp). Radio-induced apoptosis at 1, 2 and 8 Gy was measured by flow cytometry using annexin V/propidium iodide.</p> <p>Results</p> <p>Radiation-induced apoptosis increased in order to radiation dose and data fitted to a semi logarithmic mathematical model. A positive correlation was found among radio-induced apoptosis values at different radiation doses: 1, 2 and 8 Gy (p < 0.0001 in all cases). Mean DSB/Gy/DNA unit obtained was 1.70 ± 0.83 (range 0.63-4.08; median, 1.46). A statistically significant inverse correlation was found between initial damage to DNA and radio-induced apoptosis at 1 Gy (p = 0.034). A trend toward 2 Gy (p = 0.057) and 8 Gy (p = 0.067) was observed after 24 hours of incubation.</p> <p>Conclusions</p> <p>An inverse association was observed for the first time between these variables, both considered as predictive factors to radiation toxicity.</p
Clinical relevance of monitoring serum levels of adalimumab in patients with rheumatoid arthritis in daily practice
[Objectives]: We aimed to assess the usefulness of measuring serum levels of adalimumab (ADL) and anti-ADL antibodies in 57 patients with rheumatoid arthritis (RA) treated with ADL for at least 3 months in daily practice. [Methods]: All patients received concomitant disease-modifying anti-rheumatic drug (DMARD). Receiver-operator characteristics (ROC) analysis was used to obtain the cut-off value of ADL for low disease activity (DAS28-ESR ≤3.2). [Results]: Anti-ADL antibodies were detected in 4 (7%) patients with a mean (SD) DAS28 score of 4.6 (0.9). Patients with positive anti-ADL antibodies had significantly lower levels of ADL and higher DAS28 scores than those with negative antibodies. Patients with DAS28 ≤3.2 as compared with patients with DAS28 >3.2 showed significantly better SDAI score, higher serum concentrations of ADL and none of them showed anti-ADL antibodies. The cut-off of serum level of ADL for DAS28 11.3 mg/L. Patients in the medium group were closed to clinical remission (median DAS28 2.7) and patients in the high group were on clinical remission (DAS28 2.1). [Conclusion]: Serum levels of ADL should be maintained >4.3 mg/L. In patients with ADL levels >11.3 mg/L, a decrease of the dose of ADL or an increase in the interval between doses may be planned. The presence of anti-ADL antibodies was associated with a loss of clinical efficacy of ADL.Peer Reviewe
Necklace-structured high-harmonic generation for low-divergence, soft x-ray harmonic combs with tunable line spacing
The extreme nonlinear optical process of high-harmonic generation (HHG) makes it possible to map the properties of a laser beam onto a radiating electron wave function and, in turn, onto the emitted x-ray light. Bright HHG beams typically emerge from a longitudinal phased distribution of atomic-scale quantum antennae. Here, we form a transverse necklace-shaped phased array of linearly polarized HHG emitters, where orbital angular momentum conservation allows us to tune the line spacing and divergence properties of extreme ultraviolet and soft x-ray high-harmonic combs. The on-axis HHG emission has extremely low divergence, well below that obtained when using Gaussian driving beams, which further decreases with harmonic order. This work provides a new degree of freedom for the design of harmonic combs—particularly in the soft x-ray regime, where very limited options are available. Such harmonic beams can enable more sensitive probes of the fastest correlated charge and spin dynamics in molecules, nanoparticles, and materials.The JILA team graciously acknowledges support from the Department of Energy BES Award No. DE-FG02-99ER14982 for the experimental implementation, a MURI grant from the Air Force Office of Scientific Research under Award No. FA9550-16-1-0121 for the mid-infrared laser soft x-ray research, and a National Science Foundation Physics Frontier Center grant PHY-1734006 for theory. N.J.B. acknowledges support from National Science FoundationGraduate Research Fellowships (grant no. DGE-1650115). Q.L.D.N. acknowledges support from National Science Foundation Graduate Research Fellowships (grant no. DGE-1144083). J.S.R., L.P., and C.H.-G. acknowledge support from Ministerio de Ciencia e Innovación (FIS2016-75652-Pand PID2019-106910GB-I00). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 851201). J.S.R., L.P., and C.H.-G. also acknowledge support from Junta de Castilla y León FEDER funds (project no. SA287P18). L.R. acknowledges support from Ministerio de Educación, Cultura y Deporte (FPU16/02591). C.H.-G. acknowledges Ministerio de Ciencia, Innovación, y Universidades for Ramón y Cajal contract (RYC-2017-22745), cofunded by the European Social Fund. L.R., J.S.R., L.P., and C.H.-G. thankfully acknowledge the computer resources at MareNostrum and the technical support provided by Barcelona Supercomputing Center (FI-2020-3-0013)
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