Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Mais filtros












Base de dados
Intervalo de ano de publicação
1.
Phys Rev Lett ; 119(18): 182501, 2017 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-29219591

RESUMO

We report the measurement of the beam-vector and tensor asymmetries A_{ed}^{V} and A_{d}^{T} in quasielastic (e[over →],e^{'}p) electrodisintegration of the deuteron at the MIT-Bates Linear Accelerator Center up to missing momentum of 500 MeV/c. Data were collected simultaneously over a momentum transfer range 0.1

2.
Phys Rev Lett ; 107(25): 252501, 2011 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-22243068

RESUMO

We report a precision measurement of the deuteron tensor analyzing powers T(20) and T(21) at the MIT-Bates Linear Accelerator Center. Data were collected simultaneously over a momentum transfer range Q=2.15-4.50 fm(-1) with the Bates Large Acceptance Spectrometer Toroid using a highly polarized deuterium internal gas target. The data are in excellent agreement with calculations in a framework of effective field theory. The deuteron charge monopole and quadrupole form factors G(C) and G(Q) were separated with improved precision, and the location of the first node of G(C) was confirmed at Q=4.19±0.05 fm(-1). The new data provide a strong constraint on theoretical models in a momentum transfer range covering the minimum of T(20) and the first node of G(C).

3.
J Toxicol ; 2009: 532640, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-20107587

RESUMO

This study investigated the relationship of children's autism symptoms with their toxic metal body burden and red blood cell (RBC) glutathione levels. In children ages 3-8 years, the severity of autism was assessed using four tools: ADOS, PDD-BI, ATEC, and SAS. Toxic metal body burden was assessed by measuring urinary excretion of toxic metals, both before and after oral dimercaptosuccinic acid (DMSA). Multiple positive correlations were found between the severity of autism and the urinary excretion of toxic metals. Variations in the severity of autism measurements could be explained, in part, by regression analyses of urinary excretion of toxic metals before and after DMSA and the level of RBC glutathione (adjusted R(2) of 0.22-0.45, P < .005 in all cases). This study demonstrates a significant positive association between the severity of autism and the relative body burden of toxic metals.

4.
Phys Rev Lett ; 101(4): 042501, 2008 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-18764321

RESUMO

We report new measurements of the neutron charge form factor at low momentum transfer using quasielastic electrodisintegration of the deuteron. Longitudinally polarized electrons at an energy of 850 MeV were scattered from an isotopically pure, highly polarized deuterium gas target. The scattered electrons and coincident neutrons were measured by the Bates Large Acceptance Spectrometer Toroid (BLAST) detector. The neutron form factor ratio GEn/GMn was extracted from the beam-target vector asymmetry AedV at four-momentum transfers Q2=0.14, 0.20, 0.29, and 0.42 (GeV/c)2.

5.
Phys Rev Lett ; 98(5): 052301, 2007 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-17358849

RESUMO

We report the first precision measurement of the proton electric to magnetic form factor ratio from spin-dependent elastic scattering of longitudinally polarized electrons from a polarized hydrogen internal gas target. The measurement was performed at the MIT-Bates South Hall Ring over a range of four-momentum transfer squared Q2 from 0.15 to 0.65 (GeV/c)(2). Significantly improved results on the proton electric and magnetic form factors are obtained in combination with existing cross-section data on elastic electron-proton scattering in the same Q2 region.

6.
Growth ; 43(3): 188-201, 1979 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-116912

RESUMO

An experiment was conducted with young turkey poults to evaluate factors controlling glycogen metabolism in the period following hatching. Glucose and sucrose solutions were given along with a standard starter diet. Liver and carcass glycogen were measured on days 1, 4 and 6. Liver glycogen synthetase (EC 2.4.1.21) and phosphorylase (EC 2.4.1.1) were also assayed at these times. The characteristics of active and inactive glycogen synthetase at these times were determined and sensitivity of the active and inactive forms were related to physiological concentrations of glucose-6-phosphate. Supplemental glucose or sucrose increased carcass glycogen in comparison to controls; however, but sucrose was more effective than glucose in promoting liver glycogen synthesis in 4- and 6-day-old poults. There was an age dependent increase in carcass glycogen between days 1 and 6, but a decrease in liver glycogen between days 4 and 6. The activation of liver glycogen synthetase is incomplete in 1 day old poults but activity increases during the 1st week of life. Activation of glycogen synthetase decreased the apparent Ka for glucose-6-phosphate. Phosphorylase inactivation in vitro was not affected by age. Liver glucose-6-phosphate increases rapidly after hatching and the concentration is related to the in vitro Ka derived for both active and inactive synthetases. Both glucose and sucrose increased liver glucose-6-phosphate at days 4 and 6 as well as glycogen synthetase activity. The increase in enzyme activity may be caused indirectly by an allosteric effect of glucose-6-phosphate. Phosphorylase, while not affected by supplemental carbohydrates, did decrease in activity between days 4 and 6. The decrease in activity could affect the phosphorylase a/ synthetase a ratio and change glycogen metabolism.


Assuntos
Glicogênio/metabolismo , Perus/crescimento & desenvolvimento , Envelhecimento , Animais , Animais Recém-Nascidos , Dieta , Ativação Enzimática , Glucofosfatos/metabolismo , Glicogênio Sintase/metabolismo , Fígado/metabolismo , Glicogênio Hepático/metabolismo , Fosforilases/metabolismo , Perus/metabolismo
7.
Poult Sci ; 57(6): 1652-7, 1978 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-220598

RESUMO

An experiment was conducted with turkey hens to investigate the effect of substituting 30% of the carbohydrate calories with corn oil, 1,3-butanediol, or glycerol. Birds fed additional corn oil had the lowest liver glycogen concentration. Corn oil increased phosphorylase, a total phosphorylase, and glycogen synthetase I in comparison to the controls. Also, additional corn oil resulted in the highest specific activity of glucose-6-phosphatase. Dietary glycerol caused the highest concentration of liver glycogen. Glycerol increased glycogen synthetase I, but had little effect upon total activity in comparison to butanediol in the diet. Both butanediol and glycerol gave similar phosphorylase a activity, but butanediol increased total activity. The fat-fed and control-fed hens regulated hepatic glycogen concentration through phosphorylase, while glycerol and butanediol-fed hens regulated glycogen through glycogen synthetase. In vitro activation of glycogen synthetase I was deficient in hens fed additional corn oil, indicating a lack of glycogen synthetase phosphatase activity. The order of activation (glycerol greater than butanediol greater than control greater than corn oil) corresponds to the rank of glycogen concentrations


Assuntos
Metabolismo Energético , Glicogênio Hepático/metabolismo , Perus/metabolismo , Animais , Butileno Glicóis/metabolismo , Feminino , Glucose-6-Fosfatase/metabolismo , Glicerol/metabolismo , Glicogênio Sintase/metabolismo , Fígado/enzimologia , Óleos/metabolismo , Fosforilases/metabolismo , Zea mays
8.
Poult Sci ; 57(5): 1460-2, 1978 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-724607

RESUMO

Carcass glycogen was degraded by chicks at a faster rate than liver glycogen during the first 72 hr of a 120 hr fast. Degradation of both sources of glycogen proceeded at a slower rate during the final 48 hr. Carcass glycogen was repleted at a greater rate than liver glycogen.


Assuntos
Galinhas/metabolismo , Glicogênio/metabolismo , Animais , Glucose/metabolismo , Glicogênio/biossíntese , Glicogênio Hepático/biossíntese
9.
Poult Sci ; 57(3): 747-51, 1978 May.
Artigo em Inglês | MEDLINE | ID: mdl-674049

RESUMO

Fertile eggs from Large White turkey hens were classified according to weight at time of incubation. Glycogen was measured in the 21-day-old embryo and one-day-old poult. Liver glycogen was positively correlated with initial egg weight in the 21-day-old embryo and negatively related to initial egg weight in the one-day-old poult. Glycogen recycling was evident in the one-day-old poult. Maximum accumulation of 14C-glucose as glycogen occurred 60 min post injection. Liver phosphorylase a level was higher in the one-day-old poult than the embryo. Total phosphorylase per gram of liver tissue was not different between the two age groups. Liver phosphorylase b was subject to conversion to phosphorylase a in both age groups. Avian phosphorylase exists in both the active and inactive form.


Assuntos
Glicogênio/metabolismo , Glicogênio Hepático/metabolismo , Perus/metabolismo , Animais , Glucose/metabolismo , Fígado/enzimologia , Glicogênio Hepático/biossíntese , Fosforilases/metabolismo , Perus/embriologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...