RESUMO

The luminescent and dosimetric properties of the MgB4O7 phosphor co-doped with Tm and Dy ions (MgB4O7:Tm,Dy) obtained by the solution combustion technique were investigated. With the prepared material, sintered dosimeters in pellet form were made. The MgB4O7 dosimeters doped with Tm and Dy with 0.25 and 0.10 mol% respectively and sintered at 1223 K for 3 h showed a sensitivity almost 11 times greater than the sensitivity of the TLD-100 commercial dosimeter. The TL response as a function of the gamma dose showed linearity up to 50 Gy followed by a supralinearity region and, above 500 Gy, the saturation region of the electron traps is reached. The fading of the main TL peak was negligible in the first five days after irradiation reaching 13% after 60 days and the lower detection limit was 43 µGy. The kinetic parameters were determined using the deconvolution method revealing general and second order kinetics. The morphology, crystallography and photoluminescence of the prepared phosphor samples are also reported.

RESUMO

STUDY QUESTION: Is there an association between iron intake and ovarian reserve among women seeking fertility care? SUMMARY ANSWER: Supplemental iron intake above 45 mg/day is associated with lower ovarian reserve among women seeking fertility care. WHAT IS KNOWN ALREADY: Although the literature regarding iron intake in relation to ovarian reserve is scant and inconsistent, some evidence suggests that iron may have gonadotoxic effects. STUDY DESIGN, SIZE, DURATION: This observational study included 582 female participants attending the Massachusetts General Hospital Fertility Center (2007-2019) enrolled in the Environment and Reproductive Health (EARTH) Study. PARTICIPANTS/MATERIALS, SETTING, METHODS: Iron intake was estimated using a validated food frequency questionnaire. Markers of ovarian reserve included antral follicle count (AFC) (assessed via transvaginal ultrasound) and Day 3 FSH, both obtained during the course of an infertility evaluation. MAIN RESULTS AND THE ROLE OF CHANCE: Participants had a median age of 35 years and median total iron intake of 29 mg/day. Total iron intake was inversely related to AFC and this association was driven by intake of supplemental iron. Compared to women with a supplemental iron intake of ≤20 mg/day, women consuming 45-64 mg/day of supplemental iron had a 17% (-35%, 0.3%) lower AFC and women consuming ≥65 mg/day of supplemental iron had a 32% (-54%, -11%) lower AFC after adjusting for potential confounders (P, linear trend = 0.003). Similarly, in a multivariable-adjusted analysis, Day 3 FSH levels were 0.9 (0.5, 1.3) IU/ml higher among women with a supplemental iron intake of ≥65 mg/day when compared to women with a supplemental iron intake of ≤20 mg/day (P, linear trend = 0.02). LIMITATIONS, REASONS FOR CAUTION: Iron intake was estimated using a method that relies on self-report and we had no biomarkers of iron status in our participants; only 36 women consumed ≥45 mg/day of supplemental iron. WIDER IMPLICATIONS OF THE FINDINGS: Since all study participants were seeking fertility treatment, our findings may not apply to women in the general population. Although our findings are consistent with studies of women with iron overload, given the paucity of literature on this topic, it is essential that this question is revisited in studies designed to better understand the dose-response relation of this association across the entire distribution of ovarian reserve and the risk-benefit balance of pre-conceptional iron supplementation given its many positive effects on pregnancy outcomes. STUDY FUNDING/COMPETING INTEREST(S): The project was funded by Grants R01ES022955, R01ES033651, R01ES009718, P30ES000002, and P30DK046200 from the National Institutes of Health. N.J.-C. was supported by a Fulbright Scholarship. N.J.-C., M.M., L.M.-A., E.O.-P., S.W., I.S., and J.E.C. declare no conflict of interest related to the work in the manuscript. R.H. has received grants from the National Institute of Environmental Health Sciences. TRIAL REGISTRATION NUMBER: N/A.

Assuntos

RESUMO

This work investigates how docosahexaenoic acid (DHA) modifies the effect of Cholesterol (Chol) on the structural and dynamical properties of dipalmitoylphosphatidylcholine (DPPC) membrane. We employ low-cost and non-invasive methods: zeta potential (ZP), conductivity, density, and ultrasound velocity, complemented by molecular dynamics simulations. Our studies reveal that 30% of DHA added to the DPPC-Chol system tends to revert Chol action on a model lipid bilayer. Results obtained in this work shed light on the effect of polyunsaturated fatty acids - particularly DHA - on lipid membranes, with potential preventive applications in many diseases, e.g. neuronal as, Alzheimer's disease, and viral, as Covid-19.

Assuntos

RESUMO

Fluorescence spectroscopy and Molecular Dynamics results show that cholesterol reduces water along the chains in ether lipids by changing the water distribution pattern between tightly and loosely bound water molecules. Water distribution was followed by emission spectra and generalized polarization of 6-dodecanoyl-2-dimethyl aminonaphthalene (Laurdan) inserted in 1,2-dimiristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine (14: 0 Diether PC) membranes. Molecular Dynamics simulations indicate that the action of cholesterol could be different in ether PC in comparison to ester PC. In addition, Cholesterol seems to act "per se" as an additional hydration center in ether lipids. Regardless of the phase state, cholesterol both in DMPC and 14:0 Diether PC vesicles, changed the distribution of water molecules decreasing the dipole relaxation of the lipid interphase generating an increase in the non-relaxable population. Above 10% Cholesterol/14:0 Diether PC ratio vesicles' interphase present an environment around Laurdan molecules similar to that corresponding to ester PC.

Assuntos

RESUMO

This work reports the effect of hydroxy-xanthones (XAs) on 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC) bilayers as determined by ultrasound velocimetry, densimetry and molecular dynamics simulations. XAs with different number of hydroxyl group were studied. Experimental results, in good agreement with molecular dynamics simulations, revealed that the presence of XAs in the systems studied increases fluidity while simultaneously decreses the compressibility of both membranes. This ´apparent contradiction´ ceases to exist when the particular geometrical structure of the xanthones is taken into account: the planar shape of their fused aromatic rings might allow them to pack efficiently among the hydrocarbon tails of the lipids, thus decreasing compressibility, while their presence weakens or disrupts methylene-methylene interchain interactions, thus increasing membrane fluidity and decreasing their melting temperature.

Assuntos

RESUMO

INTRODUCTION: Living kidney donation (LKD) is one of the most used alternatives in the field of organ transplantation. OBJECTIVE: Analyze the attitude toward LKD among the population of Havana, Cuba. METHODS: Population under study. Population resident in Havana, Cuba. INCLUSION CRITERIA: Sample of population over 15 years stratified by age and sex. INSTRUMENT: Validated questionnaire of attitude toward donation and transplant "PCID-DVR-Ríos," self-administered and anonymously filled out. STATISTICS: χ2, Student t test, and a logistic regression analysis. RESULTS: A total of 920 respondents have been included in the study. A total of 85.5% (n = 787) are in favor of the related LKD. In our study, 26.5% (n = 244) would remain in favor of unrelated LKD. Regarding the related LKD, the following variables remain independent in the multivariate analysis: 1. having studies (odds ratio [OR] = 3.649; P = .018); 2. attitude toward cadaveric organ donation (OR = 8.547; P < .001); 3. religion (OR = 4.385; P = .001); 4. opinion of the couple (OR = 4.672; P = .028); and 5. risk with living donation (OR = 10.989; P = .003). CONCLUSIONS: The population of Havana has a very favorable attitude toward related LKD. Only a quarter of respondents are in favor of unrelated LKD.

Assuntos

Assuntos

RESUMO

The pig industry is growing very fast in Argentina with an increasing need for replacement animals, feedstuff and transportation of animals. One of the main competitive advantages of the Argentinian pig industry is its being free of most major pig diseases. Within this context, applying measures aimed to reduce the risk of introduction and spread of pathogens is critical. The aim of the present study was to assess the biosecurity of Argentinian pig farms. Two types of farms were assessed: firstly, all official suppliers of high-genetic-value (n = 110) and secondly, a sample from commercial farms (n = 192). Data on the external and internal biosecurity practices applied on the farms was collected with a questionnaire. Data was analysed using a correspondence analysis and a hierarchical clustering analysis, which allowed identification of types of farms with regard to the biosecurity measures applied. Key variables characterizing the clusters were identified through an indicator value analysis. In addition, the external biosecurity of the farms was evaluated by using risk assessment tools with respect to the potential introduction of porcine epidemic diarrhoea virus. Results made evident three clusters: the first one which, amongst other measures, applied several barriers to prevent the entry of people, trucks and other vehicles, and could be considered as a group of high biosecurity, and the two other groups which applied a lower number of external and internal biosecurity measures. The results of the risk assessment showed that the routes with the highest risk of disease introduction were: replacement animals, vehicles transporting feed or animals, and visitors. The assessment of the external biosecurity showed that most Argentinian farms were not prepared for the contingency of a pathogen such as porcine epidemic diarrhoea virus. Special efforts should be made in official suppliers of high-genetic-value farms with poor biosecurity scores since they are at the top of the pig production chain and can be key for the spread of diseases.

Assuntos

RESUMO

INTRODUCTION: Immigrants from Ecuador represent the largest group of Latin Americans in Spain and are, therefore, a subgroup of interest to understand their attitudes and influences in respect to organ donation and transplantation. OBJECTIVE: To analyze the attitude of nationals of Ecuador residing in Spain regarding deceased organ donation. METHODS: The study population included the Ecuadorian population residing in Spain. A sample of population older than 15 years was obtained randomly and stratified by age and sex (n=461). Attitude was assessed using a validated questionnaire on psychosocial aspects toward organ donation (PCID-DTO-Ríos). Assistance from immigration support associations in Spain was needed to advice on the location of potential respondents. RESULTS: Attitude toward cadaveric donation was favorable in 59% (n=271) of respondents, 12% (n=57) were against cadaveric donation, and 29% (n=133) were undecided. Several variables were associated with having a more favorable attitude. In the multivariate analysis, the following variables were independently associated with a more positive attitude toward organ donation: 1. level of formal education (odds ratio [OR]=6.849 [25.641-1.818]; P = .004); 2. being in favor of donating a family member's organs (OR=8.849 [20.833-3.717]; P < .001); 3. having commented at a family level about transplant (OR=3.717 [6.578-2.109]; P < .001); 4. not being concerned about the possible mutilation of the body after donation (OR=4.608 [8.547-2.487]; P < .001) and 5. knowing the attitude of one's religion toward donation (OR=7.462 [34.482-1.623]; P = .010). CONCLUSIONS: The attitude toward cadaveric organ donation among the Ecuadorian population residing in Spain is less favorable than that of the Spanish population and is determined by many different psychosocial variables.

Assuntos

RESUMO

INTRODUCTION: The Bolivian population is growing in Spain. The knowledge and acceptance of the concept of brain death are fundamental. OBJECTIVE: To analyze the level of understanding of the brain death concept among the population of Bolivians residing in Spain. METHODS: The study population was Bolivians living in Spain. The inclusion criteria were being older than 15 years, being born in Bolivia, and residing in Spain; participants were selected randomly from this group and stratified by age and sex. Knowledge of the concept of brain death was assessed using a validated questionnaire on psychosocial aspects toward organ donation. A group of people to be surveyed was randomly selected. Assistance from immigration support associations in Spain was needed to advise on the location of potential respondents. The survey was self-administered and completed anonymously. RESULTS: Of the 206 respondents, 27% understood brain death (BD) and believed that this was the death of an individual. Of the rest, 18% did not understand it and the remaining 55% believed it did not mean the death of a patient. Those who understood the concept of BD were more in favor of deceased donation than those who did not (52% vs 47%; P = .886). None of the sociopersonal variables analyzed is associated with knowledge of the concept of BD. A high percentage of respondents indicated fear of apparent death during organ donation. CONCLUSIONS: The majority of the Bolivian population residing in Spain does not understand the concept of BD. Contrary to most psychosocial studies, it is not associated with attitudes toward organ donation or other sociopersonal factors.

Assuntos