9,430 research outputs found
The relationship between dental status, food selection, nutrient intake, nutritional status, and body mass index in older people
This paper reviewed the findings from a national survey in Great Britain which assessed whether dental status affected older people's food selection, nutrient intake, and nutritional status. The survey analyzed national random samples of free-living and institution subjects for dental examination, interview, and four-day food diary as well as blood and urine tests In the free-living sample, intakes of non-starch polysaccharides, protein, calcium, non-heme iron, niacin, and vitamin C were significantly lower in edentulous as compared to dentate subjects. People with 21 or more teeth consumed more of most nutrients, particularly non-starch polysaccharides. This relationship in intake was not apparent in the hematological analysis. Plasma ascorbate and retinol were the only analytes significantly associated with dental status. Having 21 or more teeth increased the likelihood of having an acceptable body mass index (BMI). Thus, maintaining a natural and functional dentition defined as having more than twenty teeth into old age plays an important role in having a healthy diet rich in fruits and vegetables, a satisfactory nutritional status, and an acceptable BMI
Close-packed structures and phase diagram of soft spheres in cylindrical pores
It is shown for a model system consisting of spherical particles confined in cylindrical pores that the first ten close-packed phases are in one-to-one correspondence with the first ten ways of folding a triangular lattice, each being characterized by a roll-up vector like the single-walled carbon nanotube. Phase diagrams in pressure-diameter and temperature-diameter planes are obtained by inherent-structure calculation and molecular dynamics simulation. The phase boundaries dividing two adjacent phases are infinitely sharp in the low-temperature limit but are blurred as temperature is increased. Existence of such phase boundaries explains rich, diameter-sensitive phase behavior unique for cylindrically confined systems
Extended Water Quality Monitoring of the Lincoln Lake Watershed
For seven years, the Lincoln Lake (Moores Creek and Beatty Branch) watershed was monitored for improvements in water quality resulting from agricultural best management practices (BMP) implemented to reduce nutrient transport. During the first three years of monitoring (1991 to 1994), nitrogen transport declined significantly (Edwards et al., 1994, 1996, and 1997) under both base and storm flow conditions. This decline in nitrogen transport was again observed in the three-year period following 1994 (Vendrell et al. 1998). This monitoring effort has demonstrated that water quality bas improved in the Lincoln Lake watershed. However, since the nitrogen transport continued to decline and there was some indication that phosphorus may begin to decline, monitoring was extended for another year (1998)
Effective potentials and electrostatic interactions in self-assembled molecular bilayers II: the case of biological membranes
We propose a very simple but realistic enough model which allows to include a
large number of molecules in molecular dynamics MD simulations of these
bilayers, but nevertheless taking into account molecular charge distributions,
flexible amphiphilic molecules and a reliable model of water. All these
parameters are essential in a nanoscopic scale study of intermolecular and long
range electrostatic interactions. This model was previously used by us to
simulate a Newton black film and in this paper we extend our investigation to
bilayers of the biological membrane type. The electrostatic interactions are
calculated using Ewald sums and, for the macroscopic long range electrostatic
interactions, we use our previously proposed coarsed fit of the (perpendicular
to the bilayer plane) molecular charge distributions with gaussian
distributions. To study an unique biological membrane (not an stack of
bilayers), we propose a simple effective external potential that takes into
account the microscopic pair distribution functions of water and is used to
simulate the interaction with the surrounding water. The method of effective
macroscopic and external potentials is extremely simple to implement in
numerical simulations, and the spatial and temporal charge inhomogeneities are
then roughly taken into account. Molecular dynamics simulations of several
models of a single biological membrane, of neutral or charged polar
amphiphilics, with or without water (using the TIP5P intermolecular potential
for water) are included
A split-cavity design for the incorporation of a DC bias in a 3D microwave cavity
We report on a technique for applying a DC bias in a 3D microwave cavity. We
achieve this by isolating the two halves of the cavity with a dielectric and
directly using them as DC electrodes. As a proof of concept, we embed a
variable capacitance diode in the cavity and tune the resonant frequency with a
DC voltage, demonstrating the incorporation of a DC bias into the 3D cavity
with no measurable change in its quality factor at room temperature. We also
characterize the architecture at millikelvin temperatures and show that the
split cavity design maintains a quality factor , making it promising for future quantum applications
Imaging Transport Resonances in the Quantum Hall Effect
We use a scanning capacitance probe to image transport in the quantum Hall
system. Applying a DC bias voltage to the tip induces a ring-shaped
incompressible strip (IS) in the 2D electron system (2DES) that moves with the
tip. At certain tip positions, short-range disorder in the 2DES creates a
quantum dot island in the IS. These islands enable resonant tunneling across
the IS, enhancing its conductance by more than four orders of magnitude. The
images provide a quantitative measure of disorder and suggest resonant
tunneling as the primary mechanism for transport across ISs.Comment: 4 pages, 4 figures, submitted to PRL. For movies and additional
infomation, see http://electron.mit.edu/scanning/; Added scale bars to
images, revised discussion of figure 3, other minor change
Adsorption of Xe and Ar on Quasicrystalline Al-Ni-Co
An interaction potential energy between and adsorbate (Xe and Ar) and the
10-fold Al-Ni-Co quasicrystal is computed by summing over all
adsorbate-substrate interatomic interactions. The quasicrystal atoms'
coordinates are obtained from LEED experiments and the Lennard-Jones parameters
of Xe-Al, Xe-Ni and Xe-Co are found using semiempirical combining rules. The
resulting potential energy function of position is highly corrugated.
Monolayer adsorption of Xe and Ar on the quasicrystal surface is investigated
in two cases: 1) in the limit of low coverage (Henry's law regime), and 2) at
somewhat larger coverage, when interactions between adatoms are considered
through the second virial coefficient, C_{AAS}. A comparison with adsorption on
a flat surface indicates that the corrugation enhances the effect on Xe-Xe
(Ar-Ar) interactions. The theoretical results for the low coverage adsorption
regime are compared to experimental (LEED isobar) data.Comment: 12 pages, 8figure
Bacterial meningitis in older neonates
During a five-year period, 24 patients' conditions (age range, 2 to 6 weeks) were diagnosed, and they were treated for bacterial meningitis. Organisms recovered from the CSF included group B Streptococcus (n = 6), Escherichia coli (n = 5), Listeria monocytogenes (n = 5), Hemophilus influenzae (n = 4), Streptococcus pneumoniae (n = 2), and group D and group A Streptococcus (one each). Initial antimicrobial therapy must include antibiotics that are effective across this spectrum of potential pathogens. Symptoms and signs were often subtle. Six children (25%) experienced major neurologic residua, including five patients (21%) in whom hydrocephalus developed. Ultrasound examination of the head at the end of therapy was an effective technique for early assessment of neurologic sequelae
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