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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 320: 124597, 2024 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-38865885

RESUMO

The double minimum E1Σu+ state in caesium dimer was investigated by analysing spectra of the E1Σu+← X1Σg+ band system, simplified by polarisation labelling. A total of 6727 rotationally resolved transitions to levels situated in the inner well and above the internal barrier were identified and a potential energy curve allowing to reproduce their energies was constructed using the Fourier grid Hamiltonian and inverted perturbation approach methods. The unambiguity of the potential curve in view of lack of data related to levels located in the outer well is discussed.

2.
Ultramicroscopy ; 263: 113984, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38744124

RESUMO

Scanning probe microscopy (SPM) is ubiquitous in nanoscale science allowing the observation of features in real space down to the angstrom resolution. The scanning nature of SPM, wherein a sharp tip rasters the surface during which a physical setpoint is maintained via a control feedback loop, often implies that the image is subject to drift effects, leading to distortion of the resulting image. While there are in-operando methods to compensate for the drift, correcting the residual linear drift in obtained images is often neglected. In this paper, we present a reciprocal space-based technique to compensate the linear drift in atomically-resolved scanning probe microscopy images without distinction of the fast and slow scanning directions; furthermore this method does not require the set of SPM images obtained for the different scanning directions. Instead, the compensation is made possible by the a priori knowledge of the lattice parameters. The method can also be used to characterize and calibrate the SPM instrument.

3.
Environ Pollut ; 268(Pt B): 115937, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33158622

RESUMO

The aim of this work was to prepare an innovative microelemental feed additive for laying hens, based on waste biomass from the agricultural sector (alfalfa and goldenrod after CO2 extraction in supercritical state). The process was optimized by Response Surface Methodology (RSM) and the most favourable enrichment conditions were selected for Cu(II), Mn(II) and Zn(II) ions: pH - 5, sorbate concentration of Cu(II), Mn(II), Zn(II) - 10.0 mg/L for alfalfa and 10.7 mg/L for goldenrod and biomass dose - 0.1 g/L. Physicochemical properties of biomass were studied and functional groups involved in the binding of Cu(II), Mn(II), Zn(II) ions were determined (mainly carboxylic and hydroxylic groups). An interesting and unique element of this work is the verification of the properties of prepared feed additives in conditions simulating the digestive tract of animals. The release of components in solutions simulating conditions in the intestine and stomach (pH 11 and pH 1) was tested (in vitro tests). The best desorption results were achieved at a strongly acidic pH which corresponds to the stomach environment: 9.80, 14.4% Cu(II), 69.0, 66.9% (Zn), 46.5, 31.9 Mn(II) for alfalfa and goldenrod, respectively. It was concluded that the biomass enriched with micronutrients in biosorption has the potential as a feed additive for sustainable agriculture.


Assuntos
Galinhas , Micronutrientes , Adsorção , Agricultura , Animais , Biomassa , Feminino , Concentração de Íons de Hidrogênio , Íons , Cinética
4.
J Physiol Pharmacol ; 67(2): 277-86, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27226187

RESUMO

Oxidative DNA damage may be a risk factor for development of various pathologies, including malignancy. We studied inflammation triggered modulation of repair activity in the intestines of three weeks old rats injected i.p. with E.coli or S. typhimurium lipopolysaccharides (LPS) at doses of 1, 5 or 10 mg/kg. Subsequent formation in these animals of colonic preneoplastic lesions, aberrant crypt foci (ACF) was also investigated. Five days after LPS administration no differences were observed in repair rate of 1,N(6)-ethenoadenine (εA), 3,N(4)-ethenocytosine (εC) and 8-oxoguanine (8-oxoG) in intestines of these rats, as measured by the nicking assay. However a significant increase in all three repair activities was found within one and two months after S. typhimurium LPS treatment. E. coli LPS significantly increased only the 8-oxoG repair. S. typhimurium LPS stimulated mRNA transcription of pro-inflammatory proteins, lipooxygenase-12 and cyclooxygenase-2, as well as some DNA repair enzymes like AP-endonuclease (Ape1) and εC-glycosylase (Tdg). mRNA level of DNA glycosylases excising εA (MPG) and 8-oxoG (OGG1) was also increased by LPS treatment, but only at the highest dose. Transcription of all enzymes increased for up to 30 days after LPS, and subsequently decreased to the level observed before treatment, with the exception of APE1, which remained elevated even two months after LPS administration. Thus, the repair efficiency of εA, εC and 8-oxoG depends on the availability of APE1, which increases OGG1 and TDG turnover on damaged DNA, and presumably stimulates MPG. One and two months after administration of E. coli or S. typhimurium LPS, the number of aberrant crypt foci in rat colons increased in a dose and time dependent manner. Thus, inflammation stimulates the repair capacity for εA, εC and 8-oxoG, but simultaneously triggers the appearance of preneoplastic changes in the colons. This may be due to increased oxidative stress and imbalance in DNA repair.


Assuntos
Colo/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Lesões Pré-Cancerosas/induzido quimicamente , Adenina/análogos & derivados , Adenina/metabolismo , Animais , Animais Recém-Nascidos , Araquidonato 12-Lipoxigenase/genética , Colo/metabolismo , Colo/patologia , Neoplasias do Colo , Ciclo-Oxigenase 2/genética , Citosina/análogos & derivados , Citosina/metabolismo , Dano ao DNA , Escherichia coli , Guanina/análogos & derivados , Guanina/metabolismo , Inflamação/induzido quimicamente , Inflamação/metabolismo , Inflamação/patologia , Estresse Oxidativo/efeitos dos fármacos , Lesões Pré-Cancerosas/metabolismo , Lesões Pré-Cancerosas/patologia , Ratos Wistar , Salmonella typhimurium
6.
J Chem Phys ; 142(23): 234308, 2015 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-26093560

RESUMO

We have carried out the direct deperturbation analysis of about 780 rovibronic term values of the strongly spin-orbit (SO) coupled A(1)Σ(+) and b(3)Π states of the (7)Li(133)Cs molecule recorded by polarization labelling spectroscopy technique. The explicit A(1)Σ(+) ∼ b(3)ΠΩ=0,1,2 coupled-channels treatment allowed us to reproduce 95% experimental term values with a standard deviation of 0.05 cm(-1) which is close to the accuracy of the present experiment. The initial potential energy curves (PECs) of the mutually perturbed states and SO matrix elements were ab initio evaluated in the basis of the spin-averaged wave functions. The empirically refined PECs and SO functions, along with the theoretical transition dipole moments, were used to predict energy and radiative properties of the A ∼ b complex for low J levels of both (7)Li(133)Cs and (6)Li(133)Cs isotopologues. The reasonable candidates for the stimulated Raman transitions between initial Feshbach resonance states, the mixed levels of the A ∼ b complex, and absolute ground X(1)Σ(+) (v = 0 and J = 0) state were identified.

7.
Curr Med Chem ; 21(28): 3294-309, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24934345

RESUMO

4-Aminobutyric acid is an inhibitory neurotransmitter involved in the control of neuronal activity in the mammalian central nervous system. There is considerable direct and indirect evidence that impaired activity of GABAmediated inhibitory synapses may be an important causative factor in experimental and clinical seizure disorders. This review is focused on the recent development of compounds which can influence GABA neurotransmission by affecting the GABA receptors, the plasma-membrane GABA transporters (GATs) and catabolic enzyme GABA-transaminase (GABAT). These compounds have been primarily investigated in relation to epilepsy, but it has also been found that a decrease in GABA neurotransmission appears to be involved in the aetiology of several neurological disorders such as insomnia, spasticity, neuropathic pain, anxiety and other mental disorders.


Assuntos
Ácido gama-Aminobutírico/fisiologia , 4-Aminobutirato Transaminase/antagonistas & inibidores , Animais , Desenho de Fármacos , Inibidores da Captação de GABA/farmacologia , Humanos , Receptores de GABA/fisiologia
8.
Adv Med Sci ; 58(2): 429-33, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24327533

RESUMO

PURPOSE: The purpose of this study was to define the coronoid-condylar index (CCI). MATERIALS AND METHODS: The material for studies comprised 26 patients. Thirteen patients were treated for bilateral coronoid hyperplasia. The remaining 13 patients were included in the control group. Based on 3D CT measurements, the coronoidcondylar index (CCI) was calculated and assessed statistically. RESULTS: In patients with coronoid hyperplasia mean CCI was 1.25, while in the control group it was 1.00. CONCLUSION: The proposed CCI can be used for the evaluation of anomalies of the mandibular coronoid processes.


Assuntos
Cefalometria/métodos , Cefalometria/normas , Doenças Mandibulares/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Tomografia Computadorizada por Raios X/normas , Adolescente , Adulto , Feminino , Humanos , Hiperplasia/diagnóstico por imagem , Hiperplasia/patologia , Imageamento Tridimensional/métodos , Imageamento Tridimensional/normas , Masculino , Mandíbula/diagnóstico por imagem , Mandíbula/patologia , Doenças Mandibulares/patologia , Projetos Piloto , Padrões de Referência , Adulto Jovem
9.
Nano Lett ; 13(1): 43-7, 2013 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-23198917

RESUMO

We show that bismuth nanostructures form three-dimensional patterns governed by two-dimensional electronic effects. Scanning tunneling microscopy reveals that both the vertical and the lateral dimensions of the structures strongly favor certain values and that the preferred widths are substantially different for each preferred height. First-principles calculations demonstrate that this vertical-lateral correlation is governed by the Fermi surface topology and that this is itself sensitively dependent on the dimensions of the structure.

10.
Opt Express ; 19(20): 19354-64, 2011 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-21996876

RESUMO

In this paper a new technique for numerical analysis of microstructured optical fibers is proposed. The technique uses a combination of model order reduction method and discrete function expansion technique. A significant reduction of the problem size is achieved (by about 85%), which results in much faster simulations (up to 16 times) without affecting the accuracy.


Assuntos
Tecnologia de Fibra Óptica/instrumentação , Microscopia/métodos , Fibras Ópticas , Desenho de Equipamento , Reprodutibilidade dos Testes
11.
J Colloid Interface Sci ; 363(2): 579-84, 2011 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-21880324

RESUMO

We have studied the structure of salt-free lysozyme at 293 K and pH 7.8 using molecular simulations and experimental SAXS effective potentials between proteins at three volume fractions, ϕ=0.012, 0.033, and 0.12. We found that the structure of lysozyme near physiological conditions strongly depends on the volume fraction of proteins. The studied lysozyme solutions are dominated by monomers only for ϕ≤0.012; for the strong dilution 70% of proteins are in a form of monomers. For ϕ=0.033 only 20% of proteins do not belong to a cluster. The clusters are mainly elongated. For ϕ=0.12 almost no individual particles exits, and branched, irregular clusters of large extent appear. Our simulation study provides new insight into the formation of equilibrium clusters in charged protein solutions near physiological conditions.


Assuntos
Muramidase/química , Concentração de Íons de Hidrogênio , Modelos Moleculares , Soluções , Temperatura
12.
J Chem Phys ; 135(4): 044318, 2011 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-21806130

RESUMO

Polarization labeling spectroscopy technique was used to measure excitation spectra of LiCs molecule in the spectral range of 16,000-18,500 cm(-1). Four band systems were observed and assigned to transitions from the ground X(1)Σ(+) state to excited states (4)Ω = 0(+), (5)Ω = 0(+), (5)Ω = 1, and (6)Ω = 1 (in Hund's case (c) notation proper here), the latter three states being fine structure components of the states d(3)Π and e(3)Σ(+), nominally of triplet symmetry. The observed states are characterized spectroscopically and the experimental results are compared with predictions of theoretical calculations, showing accuracy of the theoretical electronic term values better than 100 cm(-1) and of the ω(e) and R(e) constants within 5%.

13.
Chaos ; 21(2): 023126, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21721768

RESUMO

In this paper we study the qualitative dynamics of piecewise-smooth slow-fast systems (singularly perturbed systems) which are everywhere continuous. We consider phase space topology of systems with one-dimensional slow dynamics and one-dimensional fast dynamics. The slow manifold of the reduced system is formed by a piecewise-continuous curve, and the differentiability is lost across the switching surface. In the full system the slow manifold is no longer continuous, and there is an O(ɛ) discontinuity across the switching manifold, but the discontinuity cannot qualitatively alter system dynamics. Revealed phase space topology is used to unfold qualitative dynamics of planar slow-fast systems with an equilibrium point on the switching surface. In this case the local dynamics corresponds to so-called boundary-equilibrium bifurcations, and four qualitative phase portraits are uncovered. Our results are then used to investigate the dynamics of a box model of a thermohaline circulation, and the presence of a boundary-equilibrium bifurcation of a fold type is shown.

14.
J Phys Condens Matter ; 22(39): 395501, 2010 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-21403230

RESUMO

Scanning tunnelling microscopy, ultraviolet photoelectron spectroscopy and current imaging tunnelling spectroscopy (STM/UPS/CITS) were used to study the topographic and electronic structure of a high-temperature structure formed on the TiO(2)(001) surface after heating at 1173 K. The STM images revealed different domain-like ordering and periodicity on the surface in comparison to those observed previously. The UPS studies showed the presence of a surface state at energy about 1.1 eV below the Fermi level. This result was confirmed by the CITS data showing pronounced periodic maxima of the electron local density of states at energy around 1.1-1.2 eV below the Fermi level and located on top of every row of the new high-temperature structure. The CITS results recorded for small grains, which coexist with the observed structure, showed that their chemical composition is closer to the Ti(2)O(3) material than to TiO(2-x) for x << 1.

15.
J Chem Phys ; 130(12): 124307, 2009 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-19334830

RESUMO

Two previously unknown (1)Pi states and one (1)Sigma(+) state of NaLi are experimentally investigated in the energy region of 34,000-36,000 cm(-1) above the bottom of the molecular ground state potential well by using polarization labeling spectroscopy technique. Potential energy curves are deduced for all three states from the observed rovibrational levels. The identity of the observed states is discussed in relation with the recently published theoretical calculations on electronic structure of NaLi by Petsalakis et al. [J. Chem. Phys. 129, 054306 (2008)] and Mabrouk and Berriche [J. Phys. B41, 155101 (2008)].

16.
Artigo em Inglês | MEDLINE | ID: mdl-19264538

RESUMO

The polarisation labelling spectroscopy technique has provided detailed information about the shape of the potential barrier to dissociation of the 2(1)Pi state in KLi. The potential curve of the 2(1)Pi state is constructed using the Inverted Perturbation Approach method. Our analysis shows that the barrier height is DeltaE=20.8+/-1.0 cm(-1) relative to the dissociation limit and the barrier maximum is located at Rbar=8.2+/-0.1 A.


Assuntos
Lítio/química , Fósforo/química , Potássio/química
17.
J Colloid Interface Sci ; 317(2): 442-8, 2008 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-17950304

RESUMO

We present a new determination method of the porosity created by the adsorption space between closed multiwalled carbon nanotubes. Using the grand canonical Monte Carlo (GCMC) simulation of nitrogen adsorption at 77 K and applying the "Karolina" algorithm, local isotherms were simulated for different distances between parallel nanotubes and finally the equation of the global adsorption isotherm was solved. This methodology leads to a satisfactory description of the experimental nitrogen adsorption data showing that the distance between nanotubes is in the range between 4 and 14 nm.

18.
J Chem Phys ; 126(19): 194313, 2007 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-17523810

RESUMO

Fourier transform spectra of near-infrared laser-induced fluorescence in (39)K(6)Li show transitions to high vibrational levels of both the X (1)Sigma(+) and a (3)Sigma(+) electronic states. These include 147 transitions into six vibrational levels of the a (3)Sigma(+) state, which lie between 7 and 88 cm(-1) below the dissociation asymptote. Unfortunately, their energies span less than 30% of the well depth. However, fitting those data to eigenvalues of analytical model potential functions whose outer limbs incorporate the theoretically predicted long-range form, V(R) approximately D-C(6)R(6)-C(8)R(8), yields complete, plausible potential curves for this state. The best fits converge to remarkably similar solutions which indicate that D(e)=287(+/-4) cm(-1) and R(e)=4.99(+/-0.09) A for the a (3)Sigma(+) state of KLi, with omega(e)=47.3(+/-1.4) and 44.2(+/-1.5) cm(-1) for (39)K(6)Li and (39)K(7)Li, respectively. Properties of the resulting potential are similar to those of a published ab initio potential and are consistent with those of the analogous states of Li(2), K(2), Na(2), and NaK.

19.
Opt Express ; 15(20): 12605-18, 2007 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-19550528

RESUMO

A highly accurate radiation boundary condition for finite difference analysis of open waveguides is introduced. The boundary condition is applicable to the structures embedded in a homogeneous medium and fitted to the cross section of the structure. The numerical tests carried out for a few types of waveguides including microstructured fibers showed that the proposed approach improves the accuracy by about an order of magnitude in comparison with the PML technique and eliminates all its disadvantages.

20.
J Chem Phys ; 124(20): 204308, 2006 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-16774333

RESUMO

The long range potential of the B 1Pi state in NaRb has been investigated by observation of rovibrational levels that it supports, including the high lying ones, with the technique of polarization labeling spectroscopy. This has allowed us to characterize the potential energy curve up to 1.9 cm(-1) from the dissociation limit. The highest observed rovibrational level v=49, J=10 has the outer turning point at R=16.48 A.

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