684 research outputs found
The first-year growth response to growth hormone treatment predicts the long-term prepubertal growth response in children
<p>Abstract</p> <p>Background</p> <p>Pretreatment auxological variables, such as birth size and parental heights, are important predictors of the growth response to GH treatment. For children with missing pretreatment data, published prediction models cannot be used.</p> <p>The objective was to construct and validate a prediction model for children with missing background data based on the observed first-year growth response to GH. The accuracy and reliability of the model should be comparable with our previously published prediction model relying on pretreatment data. The design used was mathematical curve fitting on observed growth response data from children treated with a GH dose of 33 μg/kg/d.</p> <p>Methods</p> <p>Growth response data from 162 prepubertal children born at term were used to construct the model; the group comprised of 19% girls, 80% GH-deficient and 23% born SGA. For validation, data from 205 other children fulfilling the same inclusion and treatment criteria as the model group were used. The model was also tested on data from children born prematurely, children from other continents and children receiving a GH dose of 67 μg/kg/d.</p> <p>Results</p> <p>The GH response curve was similar for all children, but with an individual amplitude. The curve SD score depends on an individual factor combining the effect of dose and growth, the 'Response Score', and time on treatment, making prediction possible when the first-year growth response is known. The prediction interval (± 2 SD<sub>res</sub>) was ± 0.34 SDS for the second treatment year growth response, corresponding to ± 1.2 cm for a 3-year-old child and ± 1.8 cm for a 7-year-old child. For the 1–4-year prediction, the SD<sub>res </sub>was 0.13 SDS/year and for the 1–7-year prediction it was 0.57 SDS (i.e. < 0.1 SDS/year).</p> <p>Conclusion</p> <p>The model based on the observed first-year growth response on GH is valid worldwide for the prediction of up to 7 years of prepubertal growth in children with GHD/ISS, born AGA/SGA and born preterm/term, and can be used as an aid in medical decision making.</p
Calculation Of The Giant Magnetocaloric Effect In The Mnfep 0.45as0.55 Compound
We report the theoretical investigations on the giant magnetocaloric compound MnFeP0.45As0.55. The magnetic state equation used takes into account the magnetoelastic effect that leads the magnetic system to order under first order paramagnetic-ferromagnetic phase transition. The model parameters were determined from the magnetization data adjustment and used to calculate the magnetocaloric thermodynamic quantities. The theoretical calculations are compared with the available experimental data.709944101-094410-5Yu, B.F., Gao, Q., Zhang, B., Mang, X.Z., Chen, Z., (2003) Int. J. Refrig., 26, p. 622Gschneidner Jr., K.A., Pecharsky, V.K., (1997) Rare Earths: Science, Technology and Application III, , edited by R. C. Bautista, C. O. Bounds, T. W. Ellis, and B. T. Kilbourn The Minerals, Metals & Materials Society, WarendaleBrown, G.V., (1976) J. Appl. Phys., 47, p. 3673Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494Tegus, O., Brück, E., Buschow, K.H.J., De Boer, F.R., (2002) Nature, 415, p. 150. , LondonMorellon, L., Algarabel, P.A., Ibarra, M.R., Blasco, J., García-Landa, B., Arnold, Z., Albertini, F., (1998) Phys. Rev. B, 58, pp. R14721Rodbell, D.S., (1961) Phys. Rev. Lett., 7, p. 1Bean, C.P., Rodbell, D.S., (1961) Phys. Rev., 126, p. 104Bacmann, M., Soubeyroux, J.-L., Barrett, R., Fruchart, D., Zach, R., Niziol, S., Fruchart, R., (1983) J. Magn. Magn. Mater., 134, p. 59Brück, E., Tegus, O., Li, X.W., Deboer, F.R., Buschow, K.H.J., (2003) Physica B, 327, p. 431Tegus, O., Brück, E., Zhang, L., Dagula, Buschow, K.H.J., De Boer, F.R., (2002) Physica B, 319, p. 174Zach, R., Guillot, M., Tobola, J., (1998) J. Appl. Phys., 83, p. 7237Tegus, O., (2003) Novel Materials for Magnetic Refrigeration, , PhD thesis, Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, Printer Partners Ipskamp B. V., ISBN: 9057761076, OctoberVon Ranke, P.J., Grangeia, D.F., Caldas, A., De Oliveira, N.A., (2003) J. Appl. Phys., 93, p. 4055Wada, H., Tanabe, Y., (2001) Appl. Phys. Lett., 79, p. 3302Wada, H., Morikawa, T., Taniguchi, K., Shibata, T., Yamada, Y., Akishige, Y., (2003) Physica B, 328, p. 11
Influence of chemical doping and hydrostatic pressure on the magnetic properties of Mn1-xFexAs magnetocaloric compounds
CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPERJ - FUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIROFAPEMIG - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAISFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOThis paper presents the results of an investigation of the magnetic and structural properties of Mn1-xFexAs compounds under hydrostatic pressure and chemical doping. The chemical doping was performed by using low Fe doping levels (x=0, 0.003, 0.006, 0.010, 0.015, and 0.018), which emulates the negative pressure effect on the crystal structure. The results of this approach were compared with the physical pressure effect (hydrostatic pressure from 0 to 2.2 kbar) on the Mn0.997Fe0.003As. Both approaches exhibit the same magnetic behaviors: the TC and saturation magnetization decrease as the pressure increases; for the highest pressure studied, an orthorhombic antiferromagnetic phase occurs below the critical temperature and coexists with the ferromagnetic hexagonal phase. The equivalence between hydrostatic pressure and chemical doping indicates that the Fe doping only causes structural deformation. In addition, we performed magnetic measurements at high temperature (up to 520 K) on the samples with x=0 and 0.003 in order to investigate the magnetic behavior above TC=310 K. These results, along with structural characterization, clearly show that between TC and Tt the system is a weak antiferromagnet with short-range order confined only in the ab plane. Finally, using the low- and high-temperature data, the magnetic phase diagrams of the compound under hydrostatic pressure and chemical doping were redrawn. © 2016 American Physical Society.This paper presents the results of an investigation of the magnetic and structural properties of Mn1-xFex As compounds under hydrostatic pressure and chemical doping. The chemical doping was performed by using low Fe doping levels (x = 0, 0.003, 0.006, 0.010, 0.015, and 0.018), which emulates the negative pressure effect on the crystal structure. The results of this approach were compared with the physical pressure effect (hydrostatic pressure from 0 to 2.2 kbar) on the Mn0.997Fe0.003As. Both approaches exhibit the same magnetic behaviors: the T-C and saturation magnetization decrease as the pressure increases, for the highest pressure studied, an orthorhombic antiferromagnetic phase occurs below the critical temperature and coexists with the ferromagnetic hexagonal phase. The equivalence between hydrostatic pressure and chemical doping indicates that the Fe doping only causes structural deformation. In addition, we performed magnetic measurements at high temperature (up to 520 K) on the samples with x = 0 and 0.003 in order to investigate the magnetic behavior above T-C = 310 K. These results, along with structural characterization, clearly show that between T-C and T-t the system is a weak antiferromagnet with short-range order confined only in the ab plane. Finally, using the low- and high-temperature data, the magnetic phase diagrams of the compound under hydrostatic pressure and chemical doping were redrawn.93519CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPERJ - FUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIROFAPEMIG - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAISFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPERJ - FUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIROFAPEMIG - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAISFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOSem informaçãoSem informaçãoSem informaçãoSem informaçãoSem informaçãoThe authors would like to thank to CNPq, CAPES, FAPERJ, FAPEMIG, FAPESP, and PROPPI-UFF for financial support
Normal Values of Circulating IGF-I Bioactivity in the Healthy Population: Comparison with five widely used IGF-I immunoassays
Background: IGF-I immunoassays are primarily used to estimate IGF-I bioactivity. Recently, an IGFI
specific Kinase Receptor Activation Assay (KIRA) has been developed as an alternative method.
However, no normative values have been established for the IGF-I KIRA.
Objective: To establish normative values for the IGF-I KIRA in healthy adults.
Design: Cross-sectional study in healthy non-fasting blood donors.
Study participants: 426 healthy individuals (310 M, 116 F; age range: 18 – 79 yrs)
Main outcome Measures: IGF-I bioactivity determined by the KIRA. Results were compared with
total IGF-I, measured by five different IGF-I immunoassays.
Results: Mean (± SD) IGF-I bioactivity was 423 (± 131) pmol/L and decreased with age (β = -3.4
pmol/L/yr, p < 0.001). In subjects younger than 55 yrs mean IGF-I bioactivity was significantly higher
in women than in men. Above this age this relationship was inverse, suggesting a drop in IGF-I
bioactivity after menopause. This drop was not reflected in total IGF-I levels. IGF-I bioactivity was
significantly related to total IGF-I (rs varied between 0.46 – 0.52; P-values < 0.001).
Conclusions: We established age-specific normative values for the IGF-I KIRA. We observed a
significant drop in IGF-I bioactivity in women between 50 and 60 years, which was not perceived by
IGF-I immunoassays. The IGF-I KIRA, when compared to IGF-I immunoassays, theoretically has the
advantage that it measures net effects of IGF-binding proteins on IGF-I receptor activation. However,
it has to be proven whether information obtained by the IGF-I KIRA is clinically more relevant than
measurements obtained by IGF-I immunoassays
Long‐distance dispersal in the short‐distance dispersing house sparrow ( Passer domesticus )
The house sparrow (Passer domesticus) is a small passerine known to be highly sedentary. Throughout a 30‐year capture–mark–recapture study, we have obtained occasional reports of recoveries far outside our main metapopulation study system, documenting unusually long dispersal distances. Our records constitute the highest occurrence of long‐distance dispersal events recorded for this species in Scandinavia. Such long‐distance dispersals radically change the predicted distribution of dispersal distances and connectedness for our study metapopulation. Moreover, it reveals a much greater potential for colonization than formerly recorded for the house sparrow, which is an invasive species across four continents. These rare and occasional long‐distance dispersal events are challenging to document but may have important implications for the genetic composition of small and isolated populations and for our understanding of dispersal ecology and evolution
Presenting features and long-term effects of growth hormone treatment of children with optic nerve hypoplasia/septo-optic dysplasia
<p>Abstract</p> <p>Background</p> <p>Optic nerve hypoplasia (ONH) with/or without septo-optic dysplasia (SOD) is a known concomitant of congenital growth hormone deficiency (CGHD).</p> <p>Methods</p> <p>Demographic and longitudinal data from KIGS, the Pfizer International Growth Database, were compared between 395 subjects with ONH/SOD and CGHD and 158 controls with CGHD without midline pathology.</p> <p>Results</p> <p>ONH/SOD subjects had higher birth length/weight, and mid-parental height SDS. At GH start, height, weight, and BMI SDS were higher in the ONH/SOD group. After 1 year of GH, both groups showed similar changes in height SDS, while weight and BMI SDS remained higher in the ONH/SOD group. The initial height responses of the two groups were similar to those predicted using the KIGS-derived prediction model for children with idiopathic GHD. At near-adult height, ONH/SOD and controls had similar height, weight, and BMI SDS.</p> <p>Conclusions</p> <p>Compared to children with CGHD without midline defects, those with ONH/SOD presented with greater height, weight, and BMI SDS. These differences persisted at 1 year of GH therapy, but appeared to be overcome by long-term GH treatment.</p
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