540 research outputs found
Topographical characteristics through the study of the thermal and hydrological disuniformity of the soil from the mesoscale. An appplication to local forecasting of ambient temperature from the TELLUS project
There are no author-identified significant results in this report
A Vibrational Circular Dichroism Approach To The Determination Of The Absolute Configuration Of Flexible And Transparent Molecules: Fluorenone Ketals Of 1,N-Diols
The infrared absorption (IR) and vibrational circular dichroism (VCD) spectra for five ketal
molecules, three of which obtained from 1,2-diols and two from 1,3-diols, were recorded in the
mid-IR region. The spectra have been satisfactorily reproduced by DFT calculations, even with
not too large wavefunction basis sets, especially due to the low number of conformers to be
considered. The mobility of some moieties provides a recognizable signature. A characteristic
couplet of VCD bands attributed to normal modes involving the methine and a phenyl ring
bonded to the stereogenic carbon atom is evidenced for two ketals of the series as a signature
of the absolute configuration; due comparison with existing literature is made. A relation is
discussed of the present VCD data with the literature VCD data of simple alcohols and diols
Treatment of malignant hypercalcaemia with aminohexane bisphosphonate (neridronate).
Twenty patients with hypercalcaemia due to malignancy, which persisted following rehydration, were treated with the bisphosphonate, aminohexane bisphosphonate (AHBP), which is structurally similar to pamidronate. The treatment given was a single infusion of 125 mg of AHBP in 500 ml of normal saline infused over 4 h. Serum and urine biochemistry were measured before and after treatment. Acute toxicity was evaluated with particular attention to gastrointestinal symptoms, acute-phase reaction and change in renal function, as judged by serum creatinine. The infusion of AHBP induced a rapid fall apparent by day 3 (P < 0.001), with a nadir at day 7. The serum calcium remained lower at days 14 and 28 than at day 0, but the numbers followed up were low (n = 5 and n = 4). In all 20 patients there was a fall in serum calcium after treatment, and in 13 (65%) normocalcaemia was achieved. Failure to respond completely to AHBP appeared to be associated with a renal mechanism of hypercalcaemia. Treatment was associated with a significant decrease in fasting urinary calcium excretion (P < 0.05). There was no change in white cell count or renal function following AHBP and only two cases of mild pyrexia after infusion. We conclude that aminohexane bisphosphonate is an effective agent in the treatment of tumour-induced hypercalcaemia, with rapid onset of effect and low toxicity
Stability of Transonic Shock Solutions for One-Dimensional Euler-Poisson Equations
In this paper, both structural and dynamical stabilities of steady transonic
shock solutions for one-dimensional Euler-Poission system are investigated.
First, a steady transonic shock solution with supersonic backgroumd charge is
shown to be structurally stable with respect to small perturbations of the
background charge, provided that the electric field is positive at the shock
location. Second, any steady transonic shock solution with the supersonic
background charge is proved to be dynamically and exponentially stable with
respect to small perturbation of the initial data, provided the electric field
is not too negative at the shock location. The proof of the first stability
result relies on a monotonicity argument for the shock position and the
downstream density, and a stability analysis for subsonic and supersonic
solutions. The dynamical stability of the steady transonic shock for the
Euler-Poisson equations can be transformed to the global well-posedness of a
free boundary problem for a quasilinear second order equation with nonlinear
boundary conditions. The analysis for the associated linearized problem plays
an essential role
Adsorption of Indium on a InAs wetting layer deposited on the GaAs(001) surface
In this work we perform a first-principles study of the adsorption properties
of an In adatom deposited on 1.75 monolayers (ML) InAs, forming a wetting layer
on GaAs with the or
reconstruction. The structural properties of these reconstructions have been
studied: we determine the equilibrium geometry of the surfaces and their
stability for various growth conditions. We have then carried out a detailed
study of the potential energy surface (PES) for an In adsorbate, finding the
minima and the saddle points. The main characteristics of the PES and the
bonding configurations of the In adatom on the surface are analyzed by
comparing with analogous studies reported in the literature, trying to extract
the effects due to: (i) the compressive strain to which the InAs adlayer is
subjected, (ii) the particular surface reconstruction, and (iii) the wetting
layer composition. We found that, in general, stable adsorption sites are
located at: (i) locations besides the As in-dimers, (ii) positions bridging two
As in-dimers, (iii) between two adjacent ad-dimers (only in ), and
(iv) locations bridging two As ad-dimers. We find also other shallower
adsorption sites which are more reconstruction specific due to the lower
symmetry of the reconstruction compared to the
reconstruction
Curcuma longa Extract Exerts a Myorelaxant Effect on the Ileum and Colon in a Mouse Experimental Colitis Model, Independent of the Anti-Inflammatory Effect
Background: Curcuma has long been used as an anti-inflammatory agent in inflammatory bowel disease. Since gastrointestinal motility is impaired in inflammatory states, the aim of this work was to evaluate if Curcuma Longa had any Methods: The biological activity of Curcuma extract was evaluated against Carbachol induced contraction in isolated mice intestine. Acute and chronic colitis were induced in Balb/c mice by Dextran Sulphate Sodium administration (5% and 2.5% respectively) and either Curcuma extract (200 mg/kg/day) or placebo was thereafter administered for 7 and 21 days respectively. Spontaneous contractions and the response to Carbachol and Atropine of ileum and colon were studied after
colitis induction and Curcuma administration. Results: Curcuma extract reduced the spontaneous contractions in the ileum and colon; the maximal response to Carbachol was inhibited in a non-competitive and reversible manner. Similar results were obtained in ileum and colon from Curcuma fed mice. DSS administration decreased the motility, mainly in the colon and Curcuma almost restored both the spontaneous contractions and the response to Carbachol after 14 days assumption, compared to standard diet, but a prolonged assumption of Curcuma decreased the spontaneous and Carbachol-induced contractions.
Conclusions: Curcuma extract has a direct and indirect myorelaxant effect on mouse ileum and colon, independent of the
anti-inflammatory effect. The indirect effect is reversible and non-competitive with the cholinergic agent. These results
suggest the use of curcuma extract as a spasmolytic agent
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