3,438 research outputs found

    Ab initio analysis of the x-ray absorption spectrum of the myoglobin-carbon monoxide complex: Structure and vibrations

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    We present a comparison between Fe K-edge x-ray absorption spectra of carbonmonoxy-myoglobin and its simulation based on density-functional theory determination of the structure and vibrations and spectral simulation with multiple-scattering theory. An excellent comparison is obtained for the main part of the molecular structure without any structural fitting parameters. The geometry of the CO ligand is reliably determined using a synergic approach to data analysis. The methodology underlying this approach is expected to be especially useful in similar situations in which high-resolution data for structure and vibrations are available.Comment: 13 pages, 3 figure

    Apgar score or birthweight in Chihuahua dogs born by elective Caesarean section : which is the best predictor of the survival at 24 h after birth?

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    In the dog, the correct management of parturition and the prompt neonatal evaluation and assistance can reduce the perinatal mortality rates that are particularly high in toy breeds. Newborn evaluation and factors addressing prognosis are pivotal to guarantee the correct neonatal assistance. Assessment of the Apgar score with viability classification and birthweight are recognized as predictors for neonatal survival in dogs, but breed-specific data are needed for a more feasible application in the dog species, in which wide differences among breeds are known. The present study aimed therefore to: (a) assess the role of Apgar score and birthweight as predictors for the survival of Chihuahua newborn puppies in the first 24 h of life; (b) to assess a cut-off of the Apgar score and birthweight values that can predict the survival of Chihuahua newborn puppies in the first 24 h after birth; (c) to assess the possible effect played by maternal parity, newborn gender and litter-size on Apgar score in Chihuahua newborn puppies, in order to provide breed-specific data for a better neonatal assistance..Data obtained from 176 normal developed Chihuahua puppies born by elective Caesarean section, showed that 62%, 28% and 10% of puppies were classified in the Apgar score classes 7\u201310, 4\u20136 and 0\u20133, respectively, with survival at 24 h after birth of 97%, 96%, 39%, in the three Apgar classes of viability, respectively. Apgar score was a better predictor for survival at 24 h after birth than birthweight (AUC 0.93, P < 0.0001; AUC 0.69, P < 0.01, respectively). Litter-size of 7 puppies/litter plays a negative effect on Apgar score. Apgar score is a better predictor of survival at 24 h than birthweight, and the best cut-off of Apgar score for survival at 24 h after birth is 4, with 96% sensitivity and 77% specificity. The different proportion of \u201cnormal viable\u201d and \u201cless viable\u201d neonates in comparison to other studies highlights that Chihuahua puppies born by elective Caesarean section should be carefully evaluated at birth to provide correct assistance

    Beyond hollowing out: Public sector managers and the use of external management consultants

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    Expenditure on management consultants in public sector organizations is generally seen as contributing to a “hollowing out” of the state through the substitution of internal management capability. However, there is little systematic evidence for this view which also ignores how public sector managers may, themselves, drive consulting use. Looking at 125 English public hospitals over 6 years, we explore the relationship between the development and composition of management functions and spending on consultants. Our findings show the absence of a substitution effect and, therefore, challenge the “hollowing out” thesis. Instead, they point to a more active, occupationally varied and political use of consultancy. We find that larger management functions overall are associated with greater reliance on consultants— a complementary relationship. However, where a higher proportion of managers are engaged in internal consulting functions, this results in the lower use of external management consultants, with implications for theory, research and policy

    Enhancing the scratch resistance of polycarbonate with poly(ethylene oxide)-silica hybrid coatings

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    Scratch-resistant coatings for bisphenol-A polycarbonate sheets were obtained by the sol–gel synthesis of an organic–inorganic hybrid system based on poly(ethylene oxide) and silica. The organic–inorganic hybrids were thermally cured into hard transparent coatings by using conventional and microwave (MW) ovens. Both techniques proved to be equally efficient in promoting the system’s crosslinking, as evaluated by 29Si MAS-NMR. The MW-assisted curing, however, was much faster. Photoelasticity analysis showed that MW-assisted curing causes localized overheating of the samples, inducing a state of residual plane stresses that bring about dimensional instability of the coated material. Instrumented scratch tests for the coated samples revealed an increase of 1 order of magnitude in the minimal load at which a scratch track appears on the sample surface. However, the friction coefficient values for samples with thermally cured coatings were lower than those produced by MW-assisted curing

    Hair and Claw Dehydroepiandrosterone Concentrations in Newborn Puppies Spontaneously Dead within 30 Days of Age

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    The latest intrauterine fetal developmental stage and the neonatal period represent the most challenging phases for mammalian offspring. Toward the term of pregnancy, during parturition, and after birth, the hypothalamic–pituitary–adrenal axis (HPA) is a key system regulating several physiologic processes, through the production of cortisol and dehydroepiandrosterone (DHEA). This study was aimed to assess DHEA concentrations in hair and claws of 126 spontaneously dead newborn puppies, classified as premature puppies (PRE-P), stillborn puppies (STILL-P) and puppies that died from the 1st to the 30th day of life (NEON-P). The possible influence of newborn sex, breed body size, and timing of death on DHEA concentrations in both matrices was evaluated. Claw DHEA concentrations were higher in the PRE-P group when compared to STILL-P and NEON-P puppies (p < 0.05), whilst no significant differences were found in hair for all the studied factors. The results confirm the hypothesis that higher amounts of DHEA are produced during the intrauterine life in dogs, also in puppies that will die soon after birth

    Peripubertal Testosterone, 17β-Estradiol and Progesterone Concentrations in Hair and Nails in Dobermann Dogs

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    Studies about puberty in dogs are few, probably because many factors are involved in the delicate process of puberty onset, leading to difficulties in the proper enrollment of subjects. Moreover, the use of blood for monitoring hormonal changes can be problematic, and not feasible for long-term studies. Hair and nails proved to be suitable matrices for the retrospective evaluation of hormones’ long-term accumulation. This study was performed using hair and nails for the evaluation of testosterone (T), 17β-estradiol (E2) and progesterone (P4) concentrations to assess possible sexual steroid changes during the peripubertal period in dogs. The results, obtained on five males and five females, showed a significant increase in T in hair and nails of males immediately before puberty. In females, a significant increase in E2 at puberty and a marked increase in P4 after puberty was found in both biological specimens. Sex-related differences were detected only for T hair concentrations, but when the sex and sampling time were considered together, hair and nails T and nails P4 concentrations allowed us to discern between male and female dogs at specific sampling times. The results from this study showed that hair and nails are useful biological specimens for the retrospective evaluation of changes in T, E2 and P4 concentrations in peripubertal dogs

    How stressful is maternity? Study about cortisol and dehydroepiandrosterone-sulfate coat and claws concentrations in female dogs from mating to 60 days post-partum

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    In dogs, the phase from mating to the end of weaning lasts about 120 days and encompasses many aspects that, interacting, contribute to increase the allostatic load. The coat and claws, useful for long-term change assessments, have the advantage of being collectable without invasiveness. In the present study, the Cortisol (C) and Dehydroepiandrosterone-sulfate (DHEA-S) concentration monthly changes in the coat and claws were studied in female dogs from mating to the end of weaning to assess Hypothalamic\u2013Pituitary\u2013Adrenal (HPA) axis activation during pregnancy and the post-partum period. The results from 15 Dobermann Pinscher female dogs showed a trend of increase of the coat C from mating to 60 days post-partum, with significant changes between mating and parturition-60 days post-partum (p < 0.01) and between the 30-day pregnancy diagnosis (PD) and 30\u201360 days post-partum (p < 0.05). The claws C trend showed significant increases between mating and 30\u201360 days post-partum (p < 0.05) and between the PD and 60 days post-partum (p < 0.01). DHEA-S in both matrices showed non-significant changes. The results suggest that maternity could play a pivotal role in the HPA axis activation, with a subsequent chronic secretion of C determining an increase in the allostatic load in the mothers. Neither maternal parity nor litter size played a significant role in the accumulation of C and DHEA-S in both matrices

    Postpartum hair cortisol, dehydroepiandrosterone sulfate and their ratio in beef cows: Exploring association with parity and conception outcome

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    Hair steroid measurement has received increasing attention for monitoring hypothalamic-pituitary-adrenal axis function, as it offers the advantages of being noninvasive, fast, and able to indicate steroid concentrations over long periods. The objects of the study were to evaluate cortisol (C) and dehydroepiandrosterone sulfate (DHEA-S) hair concentrations and their ratio (C/DHEA-S) in beef cows from calving to 100 days (d) postpartum (pp) and to assess possible differences related to parity (primiparous vs multiparous) and conception outcome (pregnant vs not pregnant). Hair samples were collected from 6 primiparous and 5 multiparous pregnant beef cows by clipping the coat at calving (T0) and every 20 d for 5 times (T1-T5), collecting only the regrown hair. Starting from the 6th-week pp, cows were submitted to artificial insemination at spontaneous estrus; by 100 d pp, 7 cows were pregnant and 4 were not pregnant. Statistical analysis showed higher hair C concentrations in the 11 cows at calving (T0) compared to all the subsequent samplings except for T1, and higher C concentrations at T1 compared to T3, T4, and T5. These results indicate that hair C concentrations in beef cows are affected by sampling time, with a decrease from calving, as reported in other matrices. When exploring changes within parity groups, no differences were found in the multiparous among sampling times, while hair C concentrations at T0 and T1 tended to be higher than at T2 (0.01 ≤ p < 0.05) and were higher (p < 0.01) than in all the subsequent samplings (T3, T4 and T5) within the primiparous group. Higher hair C concentrations were found at T0 and T1 in the primiparous compared to multiparous (p < 0.01), suggesting that primiparous cows undergo a greater stress level before and around parturition compared to multiparous, probably due to the novelty of the calving experience. No differences were detected in C hair concentrations according to conception outcome (pregnant versus not pregnant) in each sampling time. Hair DHEA-S concentrations were neither affected by time nor by parity or conception outcome. Differences in the C/DHEA-S ratio were found at T1, with higher C/DHEA-S in the multiparous compared to primiparous cows (p < 0.001), and a tendency for higher ratio in the not pregnant compared to the pregnant (0.01 ≤ p < 0.05). These results support the choice of hair as a valuable biological matrix when investigating long-time periods such as postpartum in cows and suggest an enhanced immunoprotective effect of DHEA-S in the postpartum of primiparous cows, and in cows that get pregnant within 100 d postpartum
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