Search Results - (Author, Cooperation:J. C. Smith)

2013-02-09

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Amino Acid Sequence ; Bacterial Proteins/*genetics ; Corrinoids/genetics ; Desulfovibrio desulfuricans/*genetics/metabolism ; Environmental Pollutants/*metabolism ; Ferredoxins/genetics ; Gene Deletion ; Geobacter/*genetics/metabolism ; Mercury/*metabolism ; Methylation ; Molecular Sequence Data ; *Multigene Family

2013-08-03

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Blastula/*embryology/metabolism ; Carrier Proteins/*metabolism ; Cell Cycle Proteins/*metabolism ; Chromosomal Proteins, Non-Histone/*metabolism ; *DNA Replication ; RecQ Helicases/*metabolism ; Xenopus Proteins/*metabolism ; Xenopus laevis/*embryology/genetics/metabolism

2014-07-26

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Biology/*manpower ; Biomedical Research/*manpower ; Faculty ; Family Characteristics ; Female ; Humans ; Male ; Men ; *Sex Ratio ; *Sexism ; *Women

2013-02-22

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

2018-01-09

Wiley-Blackwell

0094-8276

1944-8007

Geosciences

Physics

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The dynamics of the methyl groups in the crystalline alanine dipeptide is examined over a wide range of temperatures using elastic and inelastic neutron scattering experiments and molecular dynamics (MD) simulations of the full crystal. Neutron scattering spectra are calculated from the simulations and directly compared to the experimental profiles. The N-ter and C-ter methyl groups in the molecule have low rotational barriers, i.e., (approximately-less-than)1 kcal/mol. They undergo rotations that are activated on time scales faster than ≈1 ns at temperatures as low as 50–100 K and are on the picosecond time scale at 150 and 300 K. At 300 K the rotational motion becomes strongly diffusive in the simulation. In contrast, the side-chain methyls possess a significant intramolecular intrinsic torsional barrier, ≈3 kcal/mol. As a result, their dynamics consists of librations and rare jumps between wells. The simulations are further analyzed to characterize in detail the motions giving rise to the calculated scattering. Using a quaternion-based method the simulated methyl dynamics is decomposed into rigid-body rotational and translational components. The decomposed motions and their contributions to the calculated neutron profiles are examined.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The low-frequency (〈20 meV) polarized vibrational density of states in crystalline polyacetylene has recently been derived from inelastic neutron scattering data [J. L. Sauvajol, D. Djurado, A. J. Dianoux, N. Theophilou, and J. E. Fischer, Phys. Rev. B 43, 14 305 (1991)]. The spectral profiles were found to be highly anisotropic and to vary considerably with the chain conformation (cis or trans). Here we investigate the characteristics of the low-frequency vibrations using the molecular dynamics method. Densities of states are calculated from the simulations and directly compared with the data derived from the experiments. The anisotropic and conformation-dependent profiles are mostly well reproduced. The simulation trajectories are further analyzed so as to determine the dynamical contributions to the observed spectra. The lowest-frequency vibrations parallel to the chain axes, at 1.5 meV in the cis system and 4 meV in the trans system, are found to result from whole-molecule rigid-body translations, invariant with chain length. Conversely, the low-frequency intramolecular vibrations are weakly dependent on chain conformation but vary strongly with the chain length.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

—The rates of acetylation of choline and the mono-, di-, and tri-ethyl analogues of choline by choline acetyltransferase (acetyl-CoA: choline O-acetyltransferase; EC 2.3.1.6) were studied with a partially purified enzyme from bovine caudate nucleus. All the substrates were acetylated by ChAc. The rates of acetylation at low concentrations of substrate were choline 〉MEC 〉DEC 〉TEC, but at high concentrations MEC was acetylated more rapidly than choline. These results have been compared to those of previous workers. The mode of binding of choline and its analogues to ChAc is discussed, and it is suggested that replacement of methyl by ethyl groups results in a lower energy of binding of the substrate to the active site of the enzyme.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1745-4557

Blackwell Publishing Journal Backfiles 1879-2005

Process Engineering, Biotechnology, Nutrition Technology

Three types of restructured roasts were made from beef rounds, with or without antioxidants: (1) roasts made with top and bottom round pieces weighing 0.343-0.680 kg; (2) roasts made with top and bottom round pieces weighing 0.113-0.343 kg; and (3) roasts made with knuckles and gracilis muscles of rounds that were ground through a 3-hole kidney-shaped plate. All roasts were precooked, stored at -17°C for 10-14 days, and then reheated. Total weight loss (precooking loss + reheating loss), proximate composition and thiobarbituric acid values for lipid oxidation were not different (P〉0.05) among the three types of roasts. Juiciness and overall palatability scores were higher (P〈0.05) for roasts made with ground knuckles and gracilis muscles of the round than for the other two types of roasts. Within each roast type, use of antioxidants did not affect (P〈0.05) any of the properties determined.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The unusual temperature dependence of several optical spectroscopic vibrational bands in crystalline acetanilide has been interpreted as providing evidence for dynamic localization. Here we examine the vibrational dynamics of crystalline acetanilide over a spectral range of ∼20–4000 cm−1 using incoherent neutron scattering experiments, phonon normal mode calculations and molecular dynamics simulations. A molecular mechanics energy function is parametrized and used to perform the normal mode analyses in the full configurational space of the crystal i.e., including the intramolecular and intermolecular degrees of freedom. One- and multiphonon incoherent inelastic neutron scattering intensities are calculated from harmonic analyses in the first Brillouin zone and compared with the experimental data presented here. Phonon dispersion relations and mean-square atomic displacements are derived from the harmonic model and compared with data derived from coherent inelastic neutron scattering and neutron and x-ray diffraction. To examine the temperature effects on the vibrations the full, anharmonic potential function is used in molecular dynamics simulations of the crystal at 80, 140, and 300 K. Several, but not all, of the spectral features calculated from the molecular dynamics simulations exhibit temperature-dependent behavior in agreement with experiment. The significance of the results for the interpretation of the optical spectroscopic results and possible improvements to the model are discussed. © 1995 American Institute of Physics.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The low-frequency dynamics (〈20 meV) of pure and sodium-doped trans polyacetylene are investigated using a combination of incoherent neutron scattering spectroscopy and molecular dynamics simulations. The simulations are performed using a molecular mechanics potential function and including explicitly the three-dimensional crystal environments of the molecules. Both the experiments and the simulations indicate that doping results in a marked change in the vibrational density of states of the polyene chains in the direction perpendicular to the chain axes, a broad minimum appearing at ∼16 meV. This spectral region is dominated by intramolecular torsional displacements. The results also suggest that the mean-square displacements of the polyacetylene atoms become more isotropic on doping. The contributions of various rigid-body motions to the simulation-derived mean-square displacements and vibrations are described.

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Ninety-five patients complaining of urinary incontinence, 58 of whom had been subjected to previous unsuccessful surgery, were investigated by means of flow studies and voiding cine-urethrocystography with simultaneous pressure recordings. Patients suffering from neurological lesions or fistulae were excluded from this study. It was found that urinary stress incontinence could result from weakness of the internal urethral sphincter, detrusor instability, urethral narrowing, or any combination of these three. Clinical symptoms and signs alone did not provide an accurate diagnosis. A rational plan of treatment, based on full investigation is outlined and attention is especially drawn to the treatment by internal urethrotomy ofincontinence due to urethral narrowing which may occur as a sequel to gynaecological surgery.

Electronic Resource

1365-2559

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Aims:  Alveolar soft part sarcoma (ASPS) is a rare sarcoma in the buttocks or thigh of young adults, often with metastases to lung, brain, or bone. This study examines the morphological and clinical features of lingual ASPS.Methods and results:  Fourteen cases, in eight males and six females (ages 3–21 years, median 5 years), ranged from 8 to 50 mm, median 25 mm. All tumours were intramuscular, circumscribed and multinodular. Tumours from all but the oldest patient exhibited a predominantly solid (non-alveolar) growth pattern. Vascular invasion was common. Crystals varied in number from none or extremely rare to nearly 100% of tumour cells.Immunohistochemical results:  Fifty percent desmin positive, all focally smooth muscle antigen (SMA) positive; negative for vimentin, neural/melanocytic, myoid, histiocytic, and epithelial markers. All tumours were surgically excised; only two patients received chemotherapy. Follow-up on 10 patients showed that all patients were alive without disease (4–32, median 22 years). Only one patient had a microscopic metastasis to lung (3 years) but was without disease at 11 years.Conclusions:  Lingual ASPS is a tumour of childhood with a distinctive, predominantly solid growth pattern. Despite typical vascular invasion, the early diagnosis and small tumour size may explain its relatively good outcome.

Electronic Resource

1365-2214

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Psychology

Objective  Tracheostomies in children are increasingly performed for chronic medical conditions. There are no published studies reporting the experience of children with a tracheostomy in school. Such information would be valuable in planning the care and education of these children. The aims of this study were to identify those children with a tracheostomy in Nottinghamshire schools and determine the support they were receiving.Design, setting and participants  Questionnaire survey to families and school carers of 11 children with a tracheostomy.Results  All children of school age were in full-time education (five mainstream, five special schools). One preschool child attended a Family Centre. Four had problems finding suitable carers, delaying return to school in three. Four parents were dissatisfied with aspects of the child's experience at school: two felt the teaching staff were unsupportive, one was unhappy with the care of the tracheostomy, and one had problems funding a carer. Ten out of 11 school carers were satisfied with their training; 10 would have liked regular update sessions. The amount of care required varied. Those with complex medical problems in a special school setting needed frequent care, and one had required admission to hospital from school. One child had time off school because of lack of carer availability. Those who were severely disabled had less time off school for ill health after the tracheostomy than before the tracheostomy.Conclusion  Children with tracheostomies can successfully and safely achieve full-time education in both mainstream and special schools. A dedicated multidisciplinary team, including input from the parents, is essential to achieve this goal. Regular revision of skills and information sessions for the teaching staff would be beneficial.

Electronic Resource

1365-2559

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We reviewed 17 cases of liposarcoma with peculiar meningothelial-like whorls to determine the pathological and clinical significance of this distinctive morphological finding.〈section xml:id="abs1-2"〉〈title type="main"〉Methods and resultsSeventeen liposarcomas with concentric whorls simulating the whorls seen in meningioma, were retrieved from the soft tissue registry of the Armed Forces Institute of Pathology. There were 10 males and seven females with a mean age of 53 years (range 24–76 years). Twelve of the 17 cases were large retroperitoneal tumours (mean 170 mm in greatest dimensions). All 17 cases had whorls. Three cases were classified as well-differentiated liposarcoma with whorls and bone formation. Five cases showed coalescing of whorls into areas which may be interpreted as low to intermediate grade dedifferentiation. Five cases had spindled areas associated with the whorls which correlate with classical intermediate to high-grade dedifferentiation, Finally, four cases had a predominant spindle cell component resembling malignant fibrous histiocytoma with focal residual possible sclerosing well-differentiated liposarcoma (scattered adipocytes, adipocytic atypia and/or floret-type giant cells). The meningothelial-like whorls were clustered or scattered throughout the tumours and ranged from 0.09 mm to over 10 mm in diameter in cases with coalescent whorls. Metaplastic bone was present within the whorls or in their immediate vicinity in 10 of 17 cases. Immunohistochemically, the whorl-forming spindle cells showed α-smooth muscle actin reactivity in three of seven cases but were negative for epithelial membrane antigen, CD21, and CD35 indicating lack of relationship with meningioma and dendritic reticulum cell sarcoma, other tumours that may contain whorls. Whorls with bone formation revealed cells adjacent to the bone to be positive for osteocalcin, a marker of osteoblastic phenotype. The spindle cells of the whorls were negative for CD34 and CD31, yet these highlighted numerous capillaries inside the whorls in a concentric manner. The whorl-forming cells showed moderate to high MIB-1-index and showed p53 immunoreactivity similar to the dedifferentiated areas but differed from the areas of well-differentiated liposarcoma, which were p53-negative and showed a low MIB-1-index. Follow-up (available in 65% cases) revealed seven patients with metastases or dead of the disease and five patients with one or more recurrences.〈section xml:id="abs1-3"〉〈title type="main"〉ConclusionsThe meningothelial-like whorls represent a mesenchymal proliferation which may undergo pericytic or myofibroblastic, or occasionally osteoblastic, differentiation in liposarcoma. These whorls do not represent dendritic or perineurial/meningothelial differentiation. The significant proliferative activity, p53 reactivity and tendency to coalesce and associate with dedifferentiated liposarcoma suggest that the meningothelial whorls may represent an early sign of dedifferentiation of liposarcoma.

Electronic Resource

0040-5639

Theology and Religious Studies

BOOK REVIEWS

0026-7937

Linguistics and Literary Studies

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Quail embryos at stages 21-23 were irradiated in ovo in a Vickers-Armstrong Mk IV Hotspot irradiation unit at a dose rate of 1.6 krad min'1 as measured by ferrous sulphate dosimetry. The limb buds were removed from the embryos and the ZPAs grafted to sites prepared in the anterior margins of ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] The mesoderm-inducing activities of MEK1 and Xenopus p42mapk (Xp42) were tested by injecting RNA encoding gain-of-function mutant forms of both proteins into fertilized eggs before dissecting animal caps at the blastula stage. We used a constitu-tively active form of MEK1 (MEK1S217E/S221E) in which ...

Electronic Resource