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1.
J Synchrotron Radiat ; 30(Pt 1): 242-250, 2023 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-36601943

RESUMEN

The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science.


Asunto(s)
Fotones , Radiografía , Rayos X
2.
Opt Express ; 31(12): 19703-19721, 2023 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-37381380

RESUMEN

Methods of ablation imprints in solid targets are widely used to characterize focused X-ray laser beams due to a remarkable dynamic range and resolving power. A detailed description of intense beam profiles is especially important in high-energy-density physics aiming at nonlinear phenomena. Complex interaction experiments require an enormous number of imprints to be created under all desired conditions making the analysis demanding and requiring a huge amount of human work. Here, for the first time, we present ablation imprinting methods assisted by deep learning approaches. Employing a multi-layer convolutional neural network (U-Net) trained on thousands of manually annotated ablation imprints in poly(methyl methacrylate), we characterize a focused beam of beamline FL24/FLASH2 at the Free-electron laser in Hamburg. The performance of the neural network is subject to a thorough benchmark test and comparison with experienced human analysts. Methods presented in this Paper pave the way towards a virtual analyst automatically processing experimental data from start to end.

3.
Annu Rev Phys Chem ; 70: 45-69, 2019 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-31174459

RESUMEN

The air-water interface is ubiquitous in nature, as manifested in the form of the surfaces of oceans, lakes, and atmospheric aerosols. The aerosol interface, in particular, can play a crucial role in atmospheric chemistry. The adsorption of atmospheric species onto and into aerosols modifies their concentrations and chemistries. Moreover, the aerosol phase allows otherwise unlikely solution-phase chemistry to occur in the atmosphere. The effect of the air-water interface on these processes is not entirely known. This review summarizes recent theoretical investigations of the interactions of atmosphere species with the air-water interface, including reactant adsorption, photochemistry, and the spectroscopy of reactants at the water surface, with an emphasis on understanding differences between interfacial chemistries and the chemistries in both bulk solution and the gas phase. The results discussed here enable an understanding of fundamental concepts that lead to potential air-water interface effects, providing a framework to understand the effects of water surfaces on our atmosphere.

4.
J Synchrotron Radiat ; 24(Pt 1): 196-204, 2017 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-28009559

RESUMEN

Direct metrology of coherent short-wavelength beamlines is important for obtaining operational beam characteristics at the experimental site. However, since beam-time limitation imposes fast metrology procedures, a multi-parametric metrology from as low as a single shot is desirable. Here a two-dimensional (2D) procedure based on high-resolution Fresnel diffraction analysis is discussed and applied, which allowed an efficient and detailed beamline characterization at the SACLA XFEL. So far, the potential of Fresnel diffraction for beamline metrology has not been fully exploited because its high-frequency fringes could be only partly resolved with ordinary pixel-limited detectors. Using the high-spatial-frequency imaging capability of an irradiated LiF crystal, 2D information of the coherence degree, beam divergence and beam quality factor M2 were retrieved from simple diffraction patterns. The developed beam metrology was validated with a laboratory reference laser, and then successfully applied at a beamline facility, in agreement with the source specifications.

5.
Heredity (Edinb) ; 116(2): 167-76, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26374237

RESUMEN

A comprehensive understanding of how human disturbance affects tropical forest ecosystems is critical for the mitigation of future losses in global biodiversity. Although many genetic studies of tropical forest fragmentation have been conducted to provide insight into this issue, relatively few have incorporated landscape data to explicitly test the effects of human disturbance on genetic differentiation among populations. In this study, we use a newly developed landscape genetic approach that relies on a genetic algorithm to simultaneously optimize resistance surfaces to investigate the effects of human disturbance in the Udzungwa Mountains of Tanzania, which is an important part of a universally recognized biodiversity hotspot. Our study species is the endangered Udzungwa red colobus monkey (Procolobus gordonorum), which is endemic to the Udzungwa Mountains and a known indicator species that thrives in large and well-protected blocks of old growth forest. Population genetic analyses identified significant population structure among Udzungwa red colobus inhabiting different forest blocks, and Bayesian cluster analyses identified hierarchical structure. Our new method for creating composite landscape resistance models found that the combination of fire density on the landscape and distance to the nearest village best explains the genetic structure observed. These results demonstrate the effects that human activities are having in an area of high global conservation priority and suggest that this ecosystem is in a precarious state. Our study also illustrates the ability of our novel landscape genetic method to detect the impacts of relatively recent landscape features on a long-lived species.


Asunto(s)
Colobus/genética , Ecosistema , Genética de Población , Algoritmos , Animales , Teorema de Bayes , Análisis por Conglomerados , Conservación de los Recursos Naturales , Especies en Peligro de Extinción , Bosques , Genotipo , Actividades Humanas , Humanos , Tanzanía
8.
Rev Gastroenterol Mex ; 80(1): 13-20, 2015.
Artículo en Inglés, Español | MEDLINE | ID: mdl-25726441

RESUMEN

BACKGROUND: Functional constipation and irritable bowel syndrome with constipation are highly prevalent and affect the quality of life of those who suffer from them. AIMS: To evaluate quality of life in patients with functional constipation and irritable bowel disease in accordance with the Rome III criteria, using the PAC-QOL and SF-36 questionnaires. MATERIALS AND METHODS: A cross-sectional study was conducted using self-administered questionnaires. The PAC-QOL, SF-36, and Rome III constipation module questionnaires were applied to patients that complained of constipation at the outpatient clinic of a tertiary care hospital. The constipation subtypes were: functional constipation (no pain), irritable bowel syndrome with constipation (pain and/or discomfort ≥3 days/month), and unclassifiable constipation (pain ≤2 days/month). Data were summarized in proportions, and group comparisons were made between the scores of each of the areas of the PAC-QOL and SF-36 questionnaires using parametric tests (Student's t test and ANOVA). RESULTS: A total of 43 PAC-QOL surveys were analyzed, resulting in cases of irritable bowel syndrome with constipation (14%), functional constipation (37%), and unclassifiable constipation (49%). There were statistically significant differences (P<.05) in Physical discomfort (irritable bowel syndrome with constipation vs. functional constipation and unclassifiable constipation vs. irritable bowel syndrome with constipation), Worries and concerns (irritable bowel syndrome with constipation vs. functional constipation), and Treatment satisfaction (irritable bowel syndrome with constipation vs. functional constipation and unclassifiable constipation vs. irritable bowel syndrome with constipation). A total of 93 SF-36 questionnaires were analyzed, describing cases of irritable bowel syndrome with constipation (23%), functional constipation (27%), and unclassifiable constipation (51%). Lower physical energy was found in relation to irritable bowel syndrome with constipation vs. functional constipation (P<.0221) and unclassifiable constipation (P<.0086), respectively, and there was greater physical pain in the cases of irritable bowel syndrome with constipation vs. unclassifiable constipation (P<.0362). CONCLUSIONS: Differences in quality of life of patients presenting with constipation subtypes were identified using the PAC-QOL and SF-36 questionnaires. The patients that had the irritable bowel syndrome with constipation subtype experienced poorer quality of life in all the evaluated domains.


Asunto(s)
Estreñimiento , Síndrome del Colon Irritable , Calidad de Vida , Adulto , Anciano , Anciano de 80 o más Años , Estreñimiento/clasificación , Estreñimiento/fisiopatología , Estudios Transversales , Femenino , Humanos , Síndrome del Colon Irritable/clasificación , Síndrome del Colon Irritable/fisiopatología , Masculino , Persona de Mediana Edad , Índice de Severidad de la Enfermedad
9.
Semergen ; 46 Suppl 1: 20-27, 2020 Aug.
Artículo en Español | MEDLINE | ID: mdl-32739134

RESUMEN

BACKGROUND AND OBJECTIVES: In this moments, of extreme gravity in which we find ourselves, and in the uncertainty face about the most effective treatment against COVID-19 disease and with the aim of find the evidence that support the chloroquine/hydroxychloroquine use recommendation to treat COVID-19 disease, a systematic review of published studies and RCT studies publishes until April 28, 2020 was carried out. MATERIAL AND METHODS: A systematic search was carried out in PubMed with the keywords COVID-19 and their synonyms and hydroxychloroquine/chloroquine. The data selection and extraction was elaborated by two researchers, independently. The results were discussed with a Primary Care physicians clinical group and the results were synthesized using GRADE methodology. RESULTS: A good quality systematic review was found that includes articles with a high risk of bias. And 8 EC launched that will produce results beyond May 2020. CONCLUSIONS: Although the conclusions of the systematic review generate a low confidence in the results, and the clinical variables that show benefit are intermediate variables, the side effects are acceptable and could be minimized with the use of QT lengthening risk tools, so it is could make a weak recommendation in favor of the use of chloroquine/hydroxychloroquine in patients with mild-moderate stage COVID-19.


Asunto(s)
Cloroquina/uso terapéutico , Infecciones por Coronavirus/tratamiento farmacológico , Humanos , Hidroxicloroquina/uso terapéutico , Incertidumbre , Tratamiento Farmacológico de COVID-19
10.
J Phys Chem A ; 113(25): 6924-35, 2009 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-19476363

RESUMEN

Reactions of alkyl radicals with oxygen are key reactions in the low-temperature oxidation of hydrocarbons, but they have not been extensively studied yet in the case of cycloalkanes. Isomerizations of cycloalkylperoxy radicals and formation of cyclic ethers are especially important. In the present work, a theoretical study of the gas-phase reactions of cyclopentylperoxy and cyclohexylperoxy radicals has been carried out by means of quantum chemical calculations at the CBS-QB3 level. Computations on cyclopentylperoxy decomposition pathways are reported here for the first time. Thermochemical data have been obtained by means of isodesmic reactions, and the contribution of hindered rotors has been explicitly taken into account. Transition state theory has been used to calculate rate constants for all the elementary reactions. Three-parameter Arrhenius expressions have been derived in the temperature range 300-1000 K. Tunneling effects have been accounted for in the case of H-atom transfers. Our results compare well with experimental data and previous calculations available in the literature. In particular, the predicted rate constants for processes involving cyclohexylperoxy radicals, which have been introduced in a reaction mechanism scheme proposed before, exhibit excellent agreement with experiments at low and intermediate temperatures.


Asunto(s)
Cicloparafinas/química , Modelos Químicos , Oxígeno/química , Simulación por Computador , Radicales Libres/química , Cinética , Oxidación-Reducción , Teoría Cuántica , Temperatura , Termodinámica
11.
Chem Commun (Camb) ; (6): 718-20, 2008 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-18478701

RESUMEN

Computations show that chlorophyll a is able to coordinate a maximum of two water molecules in hydrophobic media that form a bridge between the Mg atom and the methyl ester carbonyl group.

12.
J Phys Chem A ; 112(46): 11598-610, 2008 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-18956855

RESUMEN

Whereas many studies have been reported on the reactions of aliphatic hydrocarbons, the chemistry of cyclic hydrocarbons has not been explored extensively. In the present work, a theoretical study of the gas-phase unimolecular decomposition of cyclic alkyl radicals was performed by means of quantum chemical calculations at the CBS-QB3 level of theory. Energy barriers and high-pressure-limit rate constants were calculated systematically. Thermochemical data were obtained from isodesmic reactions, and the contribution of hindered rotors was taken into account. Classical transition state theory was used to calculate rate constants. The effect of tunneling was taken into account in the case of CH bond breaking. Three-parameter Arrhenius expressions were derived in the temperature range of 500-2000 K at atmospheric pressure, and the CC and CH bond breaking reactions were studied for cyclic alkyl radicals with a ring size ranging from three to seven carbon atoms, with and without a lateral alkyl chain. For the ring-opening reactions, the results clearly show an increase of the activation energy as the pi bond is being formed in the ring (endo ring opening) in contrast to the cases in which the pi bond is formed on the side chain (exo ring opening). These results are supported by analyses of the electronic charge density that were performed with Atoms in Molecules (AIM) theory. For all cycloalkyl radicals considered, CH bond breaking exhibits larger activation energies than CC bond breaking, except for cyclopentyl for which the ring-opening and H-loss reactions are competitive over the range of temperatures studied. The theoretical results compare rather well with the experimental data available in the literature. Evans-Polanyi correlations for CC and CH beta-scissions in alkyl and cycloalkyl free radicals were derived. The results highlight two different types of behavior depending on the strain energy in the reactant.

13.
J Nutr Health Aging ; 22(7): 796-801, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30080222

RESUMEN

OBJECTIVE: To analyze the prevalence of sarcopenia in elderly care homes using the algorithm of the European Working Group on Sarcopenia in Older People (EWGSOP) and to evaluate the applicability, sensitivity, and specificity of two simplified algorithms that do not include gait speed measurement. DESIGN: Cross-sectional study. SETTING: Long-term care homes. PARTICIPANTS: 249 residents (187 females and 62 males) with a mean age of 84.9 ± 6.7 years (range, 70-106 yrs). MEASUREMENTS: Cognitive impairment was evaluated with the Pfeiffer test, functional capacity with the Barthel index, walking ability by the Functional Ambulation Classification, muscle mass by bioelectrical impedance analysis, muscle strength by handgrip dynamometry and, gait speed over a distance of 4 m. Sarcopenia was assessed using the EWGSOP-recommended algorithm and two simplified algorithms (A and B). Algorithms A and B were validated with respect to the EWGSOP algorithm using the MacNemar test and obtaining the sensitivity and specificity, kappa coefficient, and area under the receiver operating characteristic curve (AUC). RESULTS: Total or severe dependence was recorded in 67% of the 249 residents, severe or moderate cognitive impairment in 64%, inability to walk in 49%, and capacity to walk only with the aid of an ambulator or two people in 21%. The prevalence of sarcopenia was 63.0% by the EWGSOP algorithm, 62.9% by algorithm A and 63.2% by algorithm B (P = 1.000); 143 participants were diagnosed with sarcopenia by all three methods (P =1.000, K = 1.000). CONCLUSION: Further studies that include residents with functional and/or cognitive impairment are required to validate these results, comparing the diagnostic performance of the EGWSOP algorithm with that of the simplified algorithms validated in the present report.


Asunto(s)
Disfunción Cognitiva/diagnóstico , Fuerza de la Mano/fisiología , Hogares para Ancianos/estadística & datos numéricos , Fuerza Muscular/fisiología , Sarcopenia/diagnóstico , Sarcopenia/epidemiología , Anciano , Anciano de 80 o más Años , Algoritmos , Estudios Transversales , Impedancia Eléctrica , Femenino , Marcha/fisiología , Humanos , Cuidados a Largo Plazo , Masculino , Prevalencia , Caminata/fisiología
17.
Histol Histopathol ; 20(4): 1147-53, 2005 10.
Artículo en Inglés | MEDLINE | ID: mdl-16136497

RESUMEN

The effects of the intracerebroventricular (ICV) administration of crude extracts of lupin quinolizidine alkaloids (LQAs) were studied in adult rat brain tissue. Mature L. exaltatus and L. montanus seeds were collected in western Mexico, and the LQAs from these seeds were extracted and analyzed by capillary gas chromatography. This LQA extract was administered to the right lateral ventricle of adult rats through a stainless steel cannula on five consecutive days. While control animals received 10 microl of sesame oil daily (vehicle), the experimental rats (10 per group) received 20 ng of LQA from either L. exaltatus or from L. montanus. All the animals were sacrificed 40 h after receiving the last dose of alkaloids, and their brains were removed, fixed and coronal paraffin sections were stained with haematoxylin and eosin. Immediately after the administration of LQA the animals began grooming and suffered tachycardia, tachypnea, piloerection, tail erection, muscular contractions, loss of equilibrium, excitation, and unsteady walk. In the brains of the animals treated with LQA damaged neurons were identified. The most frequent abnormalities observed in this brain tissue were "red neurons" with shrunken eosinophilic cytoplasm, strongly stained pyknotic nuclei, neuronal swelling, spongiform neuropil, "ghost cells" (hypochromasia), and abundant neuronophagic figures in numerous brain areas. While some alterations in neurons were observed in control tissues, unlike those found in the animals treated with LQA these were not significant. Thus, the histopathological changes observed can be principally attributed to the administration of sparteine and lupanine present in the alkaloid extracts.


Asunto(s)
Alcaloides/toxicidad , Encéfalo/efectos de los fármacos , Lupinus , Quinolizinas/toxicidad , Animales , Conducta Animal/efectos de los fármacos , Encéfalo/citología , Encéfalo/patología , Inyecciones Intraventriculares , Masculino , Extractos Vegetales/toxicidad , Ratas , Ratas Wistar , Convulsiones/inducido químicamente , Aceite de Sésamo
18.
J Phys Chem B ; 109(48): 23024-30, 2005 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-16854000

RESUMEN

The 1,3-hydrogen shift of triazene in aqueous solution was studied with a combination of QM/MM methods. First, the different species involved were characterized and the activation free-energies calculated with ASEP/MD, a method that makes use of the mean field approximation. Then the reaction dynamics was simulated with a QM/MM/MD method. A very strong influence of the solvent was observed, both specific, with the participation of a water molecule, and from the rest of the solvent. The effect of solvation on the geometry and electron distribution of triazene is important: N-N bond lengths tend to be more similar and the molecule acquires a planar structure. For the transition state structure, a substantial degree of ionic nature was found. Dynamic solvent effects were also analyzed.

19.
SEMERGEN, Soc. Esp. Med. Rural Gen. (Ed. Impr.) ; 46(supl.1): 20-27, ago. 2020. tab, graf
Artículo en Español | IBECS (España) | ID: ibc-192623

RESUMEN

ANTECEDENTES Y OBJETIVOS: En los momentos de extrema gravedad en los que nos encontramos, y ante la incertidumbre acerca de los tratamientos más eficaces en la lucha contra la enfermedad COVID-19 y con el objetivo de conocer las evidencias que pueden sostener la recomendación de utilización de cloroquina/hidroxicloroquina en el COVID 19, se realizó una revisión sistemática de estudios publicados y EC puestos en marcha con fecha hasta 28 de abril 2020. MATERIAL Y MÉTODOS: Se realizó una búsqueda sistemática en PubMed con las palabras clave COVID-19 y sus sinónimos y cloroquina/hidroxicloroquina. La selección y extracción de los datos aparecidos en dicha búsqueda fue realizada por dos investigadores de forma independiente. Los resultados se discutieron con un grupo clínico de médicos de Atención Primaria y se sintetizaron los resultados mediante tablas de GRADE. RESULTADOS: Se encontró una revisión sistemática de buena calidad que incluye artículos con elevado riesgo de sesgos. Y 8 EC puestos en marcha que arrojarán resultados más allá de mayo de 2020. CONCLUSIONES: Aunque las conclusiones de la revisión sistemática generan una baja confianza en los resultados, y las variables clínicas que muestran beneficio son variables intermedias, los efectos secundarios son asumibles y podrían ser minimizados con el uso de herramientas de riesgo de alargamiento del QT, por lo que se podría hacer una recomendación débil a favor del uso de cloroquina/hidroxicloroquina en pacientes con COVID-19 en estadio leve-moderado


BACKGROUND AND OBJECTIVES: In this moments, of extreme gravity in which we find ourselves, and in the uncertainty face about the most effective treatment against COVID-19 disease and with the aim of find the evidence that support the chloroquine/hydroxychloroquine use recommendation to treat COVID-19 disease, a systematic review of published studies and RCT studies publishes until April 28, 2020 was carried out. MATERIAL AND METHODS: A systematic search was carried out in PubMed with the keywords COVID-19 and their synonyms and hydroxychloroquine/chloroquine. The data selection and extraction was elaborated by two researchers, independently. The results were discussed with a Primary Care physicians clinical group and the results were synthesized using GRADE methodology. RESULTS: A good quality systematic review was found that includes articles with a high risk of bias. And 8 EC launched that will produce results beyond May 2020. CONCLUSIONS: Although the conclusions of the systematic review generate a low confidence in the results, and the clinical variables that show benefit are intermediate variables, the side effects are acceptable and could be minimized with the use of QT lengthening risk tools, so it is could make a weak recommendation in favor of the use of chloroquine/hydroxychloroquine in patients with mild-moderate stage COVID-19


Asunto(s)
Humanos , Infecciones por Coronavirus/tratamiento farmacológico , Síndrome Respiratorio Agudo Grave/tratamiento farmacológico , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo/patogenicidad , Hidroxicloroquina/administración & dosificación , Cloroquina/administración & dosificación , Antimaláricos/administración & dosificación , Pandemias , Atención Primaria de Salud/organización & administración
20.
Nutrition ; 19(9): 767-71, 2003 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-12921887

RESUMEN

OBJECTIVES: We assessed which factors contribute to the high level of nutritional risk detected by the Mini Nutritional Assessment (MNA) test in institutionalized older women. To this end, we undertook a complete nutritional assessment. METHODS: A cross-sectional study in 89 older women (age range, 72-98 y) living in two private nursing homes in Granada (Spain) was carried out. The MNA test was used as an assessment tool to detect nutritional risk. The nutritional assessment included anthropometric measurements (body mass index, triceps and subscapular skinfold thicknesses, and mid-arm and calf circumferences), quantification of dietary intake (7-d weighed-food records), clinical and functional evaluations (number of drugs, Katz index, and Red Cross cognitive scale), and biological markers (albumin, prealbumin, transferrin, and lymphocyte counts). RESULTS: We found that 7.9% (n = 5) of the older women were malnourished (MNA score, 14.5 +/- 1.4), 61.8% (n = 56) were at risk of malnutrition (MNA score, 20.6 +/- 2.1), and 30.3% (n = 28) were well nourished (MNA score, 25.0 +/- 1.1) according to the MNA test. CONCLUSIONS: This high prevalence of risk of malnutrition detected by the MNA test in healthy institutionalized older women was due mainly to risk situations and self-perception of health and did not depend on age. Inadequate micronutrients intake may contribute to the development of malnutrition in this population.


Asunto(s)
Evaluación Geriátrica/métodos , Casas de Salud , Evaluación Nutricional , Trastornos Nutricionales/diagnóstico , Anciano , Anciano de 80 o más Años , Antropometría , Biomarcadores/sangre , Estudios Transversales , Registros de Dieta , Femenino , Humanos , Trastornos Nutricionales/sangre , Estado Nutricional , Medición de Riesgo
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