20,107 research outputs found
Maternal haemodynamic function differs in preâeclampsia when it is associated with a smallâforâgestationalâage newborn: a prospective cohort study
Objective
To describe maternal haemodynamic differences in gestational hypertension with smallâforâgestationalâage babies (HDP + SGA), gestational hypertension with appropriateâforâgestationalâage babies (HDPâonly) and control pregnancies.
Design
Prospective cohort study.
Setting
Tertiary Hospital, UK.
Population
Women with gestational hypertension and healthy pregnant women.
Methods
Maternal haemodynamic indices were measured using a nonâinvasive Ultrasound Cardiac Output Monitor (USCOMâ1AÂŽ) and corrected for gestational age and maternal characteristics using deviceâspecific reference ranges.
Main outcome measures
Maternal cardiac output, stroke volume, systemic vascular resistance.
Results
We included 114 HDP + SGA, 202 HDPâonly and 401 control pregnancies at 26â41 weeks of gestation. There was no significant difference in the mean arterial blood pressure (110 versus 107 mmHg, P = 0.445) between the two HDP groups at presentation. Pregnancies complicated by HDP + SGA had significantly lower median heart rate (76 versus 85 bpm versus 83 bpm), lower cardiac output (0.85 versus 0.98 versus 0.97 MoM) and higher systemic vascular resistance (1.4 versus 1.0 versus 1.2 MoM) compared with control and HDPâonly pregnancies, respectively (all P < 0.05).
Conclusion
Women with HDP + SGA present with more severe haemodynamic dysfunction than HDPâonly. Even HDPâonly pregnancies exhibit impaired haemodynamic indices compared with normal pregnancies, supporting a role of the maternal cardiovascular system in gestational hypertension irrespective of fetal size. Central haemodynamic changes may play a role in the pathogenesis of preâeclampsia and should be considered alongside placental aetiology
SHG microscopic observations of polar state in Li-doped KTaO3 under electric field
Incipient ferroelectric KTaO3 with off-center Li impurity of the critical
concentration of 2.8 mol% was investigated in order to clarify the dipole glass
state under electric field. Using optical second-harmonic generation (SHG)
microscope, we observed a marked history dependence of SHG intensity through
zero-field cooling (ZFC), zero-field heating (ZFH), field heating after ZFC
(FH/ZFC) and FH after field cooling (FH/FC). These show different paths with
respect to temperature: In the ZFC/ZFH process, weak SHG was observed at low
temperature, while in the FH/ZFC process, relatively high SHG appears in a
limited temperature range below TF depending on the field strength, and in the
FC and FH/FC processes, the SHG exhibits ferroelectric-like temperature
dependence: it appears at the freezing temperature of 50K, increases with
decreasing temperature and has a tendency of saturation. These experimental
results strongly suggest that dipole glass state or polar nano-clusters which
gradually freezes with decreasing temperature is transformed into
semi-macroscopic polar state under the electric field. However at sufficiently
low temperature, the freezing is so strong that the electric field cannot
enlarge the polar clusters. These experimental results show that the polar
nano-cluster model similar to relaxors would be more relevant in KTaO3 doped
with the critical concentration of Li. Further experiments on the anisotropy of
SHG determine that the average symmetry of the field-induced polar phase is
tetragonal 4mm or 4, which is also confirmed by the X-ray diffraction
measurement.Comment: 26 pages, 8 figures, 1 tabl
Levels of Glucose-6-phosphate Dehydrogenase in Type 1 Diabetes Mellitus patients with Nephropathy and Cardiovascular disease complication
The aim of this study is to evaluate oxidative stress in diabetes mellitus (DM) Type1 by the measurement of Glucose-6-phosphate Dehydrogenase (G-6-PD), an enzyme expressed in human RBCs, is important in the generation of reduced glutathione which is the key product in oxidative stress controls. The Study was carried on 80 samples of blood and serum of National Diabetes Center (NDC). The study groups under fasting conditions and they divided as:20 samples of diabetes mellitus patients without complications and 20 samples of diabetes mellitus with cardiovascular (CV) complications and 20 samples of diabetes mellitus with Nephropathy (Neph) complications compared with 20 control group with average age (13-67) years.. The results showed an elevation in the lipid profile and urea levels in patients groups compared with control group and a decrease in glucose-6-phosphate Dehydrogenase, HDL levels in all patients groups compared with control group
Volume of Mixing Effect on Fluid Counter-Diffusion
The counter-current diffusion-driven mixing process of two miscible fluids is studied in the absence of gravity, assuming that the mixture is non regular, that is its volume is smaller than the sum of the initial volumes of the two components. Two competing effects are present in the mixing region: on one hand, the mass flow rate of each species increases, due to the larger density of the fluid; on the other hand, though, the volumetric flux is retarded by the inward convection due to volume disappearance, which opposes the outward velocity field due to diffusion. This intuition is confirmed by the analytical result of a 1D non-ideal mixing process, showing that, in the presence of the convection induced by a volume decrease, a) the process is self-similar; b) the mass flux of each species at the interface increases by approximately 0.8 e, where e is the maximum relative volume decrease; c) the volume flux of each species decreases by approximately a 0.2 e amount. This result is further confirmed by a perturbation analysis for small e
Isotopic studies in the natural sources of radium in groundwater in Illinois
Stable and radioactive isotopes in groundwater were studied in an investigation of the natural geologic sources of high concentrations of ²²âśRa and ²²â¸Ra in confined aquifers in the Cambrian and Ordovician bedrock of northern Illinois. The covariation of šâ¸0 and D determined that the groundwater has a meteoric isotopic composition. Groundwater in unconfined aquifers has šâ¸0 values (-6.6 to -7.9â°/ââ) that are similar to contemporary meteoric water. However, a source of recharge related to glaciation is required for groundwater in confined aquifers of the Cambrian and Ordovician that is significantly depleted in šâ¸0 (šâ¸0 values range to -12.7â°/ââ and are less than -9â°/ââ over large regions) . The covariation of Âłâ´S and šâ¸0 in dissolved sulfates determined a mixing line between two sources; oxidation of sulfide minerals and dissolution of marine evaporites. Dissolved sulfates from evaporite sources are present in large concentrations in confined aquifers but are of a different isotopic composition than evaporites of Cambrian or Ordovician age. Glaciation may be important with regard to recharge of the sulfates. The ²³â´U/²³â¸U activity ratio in groundwater from the Cambrian and Ordovician are unexpectedly high; values range from 2.1 to 40.7. The lowest ratios occur in primary recharge zones. In confined aquifers values are greater than 20 over large regions. Alpha recoil damage is a mechanism that contributes to the disequilibrium. However, the regional variation in activity ratios and in ²³â´U concentrations supports the concept that glacial recharge has contributed to the high ratios. Radiological and geochemical mechanisms that partition ²³â¸U, ²³â´U and ²³â°Th on the sandstone matrix are important to the dissolved ²²âśRa concentration.U.S. Department of the InteriorU.S. Geological Surve
Gestation and Lactation Rations for Ewes
The purpose of this study is to determine wether these two forms of haylage are satisfactory both nutritionally and economically in the lactation as well as the gestation period
Glueballs in a Hamiltonian Light-Front Approach to Pure-Glue QCD
We calculate a renormalized Hamiltonian for pure-glue QCD and diagonalize it.
The renormalization procedure is designed to produce a Hamiltonian that will
yield physical states that rapidly converge in an expansion in free-particle
Fock-space sectors. To make this possible, we use light-front field theory to
isolate vacuum effects, and we place a smooth cutoff on the Hamiltonian to
force its free-state matrix elements to quickly decrease as the difference of
the free masses of the states increases. The cutoff violates a number of
physical principles of light-front pure-glue QCD, including Lorentz covariance
and gauge covariance. This means that the operators in the Hamiltonian are not
required to respect these physical principles. However, by requiring the
Hamiltonian to produce cutoff-independent physical quantities and by requiring
it to respect the unviolated physical principles of pure-glue QCD, we are able
to derive recursion relations that define the Hamiltonian to all orders in
perturbation theory in terms of the running coupling. We approximate all
physical states as two-gluon states, and use our recursion relations to
calculate to second order the part of the Hamiltonian that is required to
compute the spectrum. We diagonalize the Hamiltonian using basis-function
expansions for the gluons' color, spin, and momentum degrees of freedom. We
examine the sensitivity of our results to the cutoff and use them to analyze
the nonperturbative scale dependence of the coupling. We investigate the effect
of the dynamical rotational symmetry of light-front field theory on the
rotational degeneracies of the spectrum and compare the spectrum to recent
lattice results. Finally, we examine our wave functions and analyze the various
sources of error in our calculation.Comment: 75 pages, 17 figures, 1 tabl
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