624 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
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
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
Understanding the molecular determinants driving the immunological specificity of the protective pilus 2a backbone protein of Group B Streptococcus
The pilus 2a backbone protein (BP-2a) is one of the most structurally and functionally characterized components of a potential vaccine formulation against Group B Streptococcus. It is characterized by six main immunologically distinct allelic variants, each inducing variant-specific protection. To investigate the molecular determinants driving the variant immunogenic specificity of BP-2a, in terms of single residue contributions, we generated six monoclonal antibodies against a specific protein variant based on their capability to recognize the polymerized pili structure on the bacterial surface. Three mAbs were also able to induce complement-dependent opsonophagocytosis killing of live GBS and target the same linear epitope present in the structurally defined and immunodominant domain D3 of the protein. Molecular docking between the modelled scFv antibody sequences and the BP-2a crystal structure revealed the potential role at the binding interface of some non-conserved antigen residues. Mutagenesis analysis confirmed the necessity of a perfect balance between charges, size and polarity at the binding interface to obtain specific binding of mAbs to the protein antigen for a neutralizing response
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
Association between Grape Yeast Communities and the Vineyard Ecosystems
The grape yeast biota from several wine-producing areas, with distinct soil types and grapevine training systems, was assessed on five islands of Azores Archipelago, and differences in yeast communities composition associated with the geographic origin of the grapes were explored. Fifty-seven grape samples belonging to the Vitis vinifera grapevine cultivars Verdelho dos Acores (Verdelho), Arinto da Terceira (Arinto) and Terrantez do Pico (Terrantez) were collected in two consecutive years and 40 spontaneous fermentations were achieved. A total of 1710 yeast isolates were obtained from freshly crushed grapes and 1200 from final stage of fermentations. Twenty-eight species were identified, Hanseniaspura uvarum, Pichia terricola and Metschnikowia pulcherrima being the three most representative species isolated. Candida carpophila was encountered for the first time as an inhabitant of grape or wine-associated environments. In both sampling years, a higher proportion of H. uvarum in fresh grapes from Verdelho cultivar was observed, in comparison with Arinto cultivar. Qualitatively significant differences were found among yeast communities from several locations on five islands of the Archipelago, particularly in locations with distinctive agro-ecological compositions. Our results are in agreement with the statement that grape-associated microbial biogeography is non-randomly associated with interactions of climate, soil, cultivar, and vine training systems in vineyard ecosystems. Our observations strongly support a possible linkage between grape yeast and wine typicality, reinforcing the statement that different viti-cultural terroirs harbor distinctive yeast biota, in particular in vineyards with very distinctive environmental conditions.Joao Drumonde Neves is the recipient of a fellowship of the Azorean Government (M321/006/F/2008) and PROEMPREGO. This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI), and by national funds through FCT by the projects FCOMP-01-0124-008775, PTDC/AGR-ALI/103392/2008 and PTDC/AGR-ALI/121062/2010.info:eu-repo/semantics/publishedVersio
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