Estudio del efecto del tamaño en la estructura cristalina de nanopartículas de CoFe2O4

Se estudió como afecta el tamaño de nanopartículas de ferrita de cobalto en el desorden cristalino por efecto de superficie. Las nanopartículas se obtuvieron por el método de coprecipitación de sales. Para controlar el tamaño realizaron diferentes tratamientos térmicos posteriores a la síntesis. La estructura cristalina y la morfología se evaluaron por medio de Difracción de rayos-X y Microscopía Electrónica de Transmisión de Alta Resolución. Los resultados obtenidos demuestran en forma cuantitativa, cómo la variación en la relación superficie/volumen es responsable de las deformaciones presentes en las nanoestructuras.Fil: Menchaca Nal, Sandra. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Tecnologia En Polimeros y Nanotecnologia; ArgentinaFil: Londoño Calderon, Cesar Leandro. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Tecnologia En Polimeros y Nanotecnologia; ArgentinaFil: Pardo Saavedra, D. C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; ArgentinaFil: Pampillo, L. G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; ArgentinaFil: Socolovsky, Leandro Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; ArgentinaFil: Martinez Garcia, Ricardo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Tecnologia En Polimeros y Nanotecnologia; Argentin

Morfological study of pore widening process in anodized alumina films

Se estudiaron las características morfológicas del proceso de ensanchamiento de poros en películas de alúmina (Al2O3) nanoporosa. El montaje experimental involucra un set-up de bajo costo que utiliza aluminio comercial. El procedimiento comprende una serie de pretratamientos, un proceso de doble anodizado, y finaliza con la inmersión de la nanoestructura porosa inicialmente fabricada, en una solución acuosa de ácido sulfúrico durante diferentes intervalos de tiempo, que conduce a un ensanchamiento de poros. Se estudió la morfología de las muestras obtenidas por microscopia electrónica de barrido, y sus principales propiedades (tamaño, distribución de tamaño de poros, circularidad y porosidad) se evaluaron en función del tiempo de ensanchamiento. Los resultados obtenidos sugieren una dependencia de la morfología con el tiempo de exposición de las nanoestructuras fabricadas. Estos resultados abren la posibilidad de fabricar nanoporos con propiedades ajustables y de bajo costo.We studied the morphological characteristics of the process of widening of pores in films of nanoporous alumina (Al2O3). The experimental setup involves a set-up that uses low cost commercial aluminum. The process comprises a series of pre-treatments, a double anodizing process, and ends with the immersion of the porous nanostructure (originally manufactured) in an aqueous solution of sulfuric acid, for different time intervals (pore widening). The morphology of the obtained samples was studied by scanning electron microscopy, and its main properties (size, pore size distribution, roundness and porosity) were evaluated as a function of the widening time. The results suggest a dependency of the exposure time with the morphology of the nanostructures fabricated. These results open the possibility of fabricating nanopores with adjustable properties and in an inexpensive way.Fil: Pardo Saavedra, D. C.. Universidad de Buenos Aires. Facultad de Ingenieria. Departamento de Fisica. Laboratorio de Sólidos Amorfos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; ArgentinaFil: Londoño Calderon, Cesar Leandro. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Tecnologia En Polimeros y Nanotecnologia; Argentina; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Menchaca Nal, Sandra. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Tecnologia En Polimeros y Nanotecnologia; Argentina; ArgentinaFil: Pampillo, Laura Gabriela. Universidad de Buenos Aires. Facultad de Ingenieria. Departamento de Fisica. Laboratorio de Sólidos Amorfos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; ArgentinaFil: Martinez Garcia, Ricardo. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Tecnologia En Polimeros y Nanotecnologia; Argentina; ArgentinaFil: Socolovsky, Leandro Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina. Universidad de Buenos Aires. Facultad de Ingenieria. Departamento de Fisica. Laboratorio de Sólidos Amorfos; Argentin

Treatment of subclinical hypothyroidism does not affect bone mass as determined by dual-energy X-ray absorptiometry, peripheral quantitative computed tomography and quantitative bone ultrasound in Spanish women.

INTRODUCTION: The results of studies examining the influence of subclinical hypothyroidism (SCH) and levothyroxine (L-T4) replacement therapy on bone have generated considerable interest but also controversy. The present research aims to evaluate the effects of L-T4 treatment on different skeletal sites in women. MATERIAL AND METHODS: A group of 45 premenopausal (mean age: 43.62 ±6.65 years) and 180 postmenopausal (mean age: 59.51 ±7.90 years) women with SCH who were undergoing L-T4 replacement therapy for at least 6 months were compared to 58 pre- and 180 postmenopausal women with SCH (untreated) matched for age. The mean doses of L-T4 were 90.88 ±42.59 µg/day in the premenopausal women and 86.35 ±34.11 µg/day in the postmenopausal women. Bone measurements were obtained using quantitative bone ultrasound (QUS) for the phalanx, dual-energy X-ray absorptiometry (DXA) for the lumbar spine and hip, and peripheral quantitative computed tomography (pQCT) for the non-dominant distal forearm. RESULTS: No differences were observed between patients and untreated controls in these bone measurements except in the bone mineral density (BMD) of the spine (p = 0.0214) in postmenopausal women, which was greater in treated women than in untreated controls. CONCLUSIONS: Our results indicate that adequate metabolic control through replacement treatment with L-T4 in pre- and postmenopausal women does not affect bone mass

A search for substellar members in the Praesepe and sigma Orionis clusters

(Abridged). We have conducted deep photometric searches for substellar members of the Praesepe (0.5-1 Gyr) and sigma Orionis (3 Myr) star clusters using the Sloan i' and z' filters, the 3.5-m and the 5-m Hale telescopes on the Calar Alto and Palomar Observatories, respectively. The total area surveyed was 1177 arcmin^2 (Praesepe) and 1122 arcmin^2 (sigma Orionis) down to 5-sigma detection limits of i'= 24.5 and z'= 24 mag, corresponding to masses of 50-55 M_Jup (Praesepe) and 6 M_Jup (sigma Orionis). Besides recovering previously known cluster members reported in the literature, we have identified new photometric candidates in both clusters whose masses expand the full range covered by our study. In sigma Orionis, follow-up NIR photometry has allowed us to confirm the likely cluster membership of three newly discovered planetary-mass objects. The substellar mass function of sigma Orionis, which is complete from the star-brown dwarf borderline down to 7 M_Jup, keeps rising smoothly with a slope of alpha = 0.6^{+0.5}_{-0.1}. Very interestingly, one of the faintest Praesepe candidates for which we have also obtained follow-up JHK photometry nicely fits the expected optical and infrared photometric sequence of the cluster. From its colors, we have estimated its spectral type in the L4-L6 range. If confirmed as a true Praesepe member, it would become the first L-type brown dwarf (50-60 M_Jup) identified in an intermediate-age star cluster. Our derivation of the Praesepe mass function depends strongly on the cluster age. For the youngest possible ages (500-700 Myr), our results suggest that there is a deficit of Praesepe brown dwarfs in the central regions of the cluster, while the similarity between the Praesepe and sigma Orionis mass functions increases qualitatively for models older than 800 Myr.Comment: Accepted for publication in A&A. Figures 1, 7, and 9-12 are available in jpeg forma

Cancer Survivors\u27 Self-Efficacy and Spirituality Outcomes Following a Holistic Integrative Intervention

Cancer treatments often negatively impact health-related quality of life (HR-QOL) for cancer survivors (CS), ignoring the multi-dimensional nature of the human experience of cancer and its impact on mental and spiritual domains. A holistic integrative approach was implemented on a heterogenous population of cancer survivors during the COVID epidemic with the goal of improving their overall well-being by looking beyond physical functioning. PURPOSE: To examine the relationship between spirituality and self-efficacy of cancer survivors of all types of cancer following a holistic intervention during the COVID-19 pandemic. METHODS: Subjects were recruited via network partners and self-referral. Subjects were eligible to participate if they were cancer survivors of any type at any stage of cancer treatment; subjects were ineligible to participate if they presented with any absolute contraindications to exercise testing as per ACSM guidelines. For 16 weeks, subjects were asked to participate in three 75-minute sessions of therapeutic yoga-based with loving kindness meditation per week. Psychosocial support text messages were sent daily to subjects based on their motivational state to encourage participation in these health enhancing behaviors. Data was collected through numerous channels including BlueJay Mobile Telehealth medicine application. RESULTS: A total of 29 survivors provided informed consent. The average age of the subjects was 58.9 years, 25 female survivors and 4 male survivors; 11 of the 29 self-reported as Latino/ Hispanic. The 29 subjects were survivors of the following primary cancers: breast cancer (n=21), cervical cancer (n=2), ovarian cancer (n=1), prostate cancer (n=1), sarcoma (n=1), lymphoma (n=1), thyroid cancer (n=1), or leukemia (n=1). There is a positive association between how confident a cancer survivor feels towards performing exercise in various situations and the amount of social support they receive from their family (p\u3c.001) and friends (p\u3c.001). The individual’s confidence to overcome the obstacle to exercise and their level of hope are associated with the support they receive from loved ones. CONCLUSION: The present study suggests that to improve exercise behavior in adult cancer survivors, one should incorporate social support to strengthen barriers self-efficacy to improve outcome expectations. To further understand these associations, longitudinal research is needed and should include more survivors

The impact of different strategies to handle missing data on both precision and bias in a drug safety study: a multidatabase multinational population-based cohort study

BACKGROUND: Missing data are often an issue in electronic medical records (EMRs) research. However, there are many ways that people deal with missing data in drug safety studies. AIM: To compare the risk estimates resulting from different strategies for the handling of missing data in the study of venous thromboembolism (VTE) risk associated with antiosteoporotic medications (AOM). METHODS: New users of AOM (alendronic acid, other bisphosphonates, strontium ranelate, selective estrogen receptor modulators, teriparatide, or denosumab) aged ≥50 years during 1998–2014 were identified in two Spanish (the Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria [BIFAP] and EpiChron cohort) and one UK (Clinical Practice Research Datalink [CPRD]) EMR. Hazard ratios (HRs) according to AOM (with alendronic acid as reference) were calculated adjusting for VTE risk factors, body mass index (that was missing in 61% of patients included in the three databases), and smoking (that was missing in 23% of patients) in the year of AOM therapy initiation. HRs and standard errors obtained using cross-sectional multiple imputation (MI) (reference method) were compared to complete case (CC) analysis – using only patients with complete data – and longitudinal MI – adding to the cross-sectional MI model the body mass index/smoking values as recorded in the year before and after therapy initiation. RESULTS: Overall, 422/95,057 (0.4%), 19/12,688 (0.1%), and 2,051/161,202 (1.3%) VTE cases/participants were seen in BIFAP, EpiChron, and CPRD, respectively. HRs moved from 100.00% underestimation to 40.31% overestimation in CC compared with cross-sectional MI, while longitudinal MI methods provided similar risk estimates compared with cross-sectional MI. Precision for HR improved in cross-sectional MI versus CC by up to 160.28%, while longitudinal MI improved precision (compared with cross-sectional) only minimally (up to 0.80%). CONCLUSIONS: CC may substantially affect relative risk estimation in EMR-based drug safety studies, since missing data are not often completely at random. Little improvement was seen in these data in terms of power with the inclusion of longitudinal MI compared with cross-sectional MI. The strategy for handling missing data in drug safety studies can have a large impact on both risk estimates and precision