Publications by authors named "Litvin I"

Unlabelled: The aim of this study was to evaluate corneal biomechanical properties in myopic patients after ReLEx SMILE and FemtoLASIK surgeries using the Corvis ST analyzer.

Material And Methods: The SMILE group comprised 23 patients (46 eyes) with spherical refraction -3.8±1.

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We investigate the effect of manipulating the laser quality factor and the spectral properties of the gain medium on an oligomer-based plasmonic nanolaser. We develop different designs of the oligomer resonators, decreasing the lasing threshold and increasing the mode lifetime to improve the lasing efficiency. Based on the designs we are able to decrease the lasing threshold by a factor of ten.

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Objective: To assess perinatal outcomes of first pregnancy after remission from gestational trophoblastic neoplasia and the impact of the time between the end of chemotherapy and the subsequent pregnancy.

Data Sources: The Medical Subject Headings related to perinatal outcomes, chemotherapy, and gestational trophoblastic neoplasia were used alone or in combination to retrieve relevant articles. We searched all references registered until April, 2019 in Embase, LILACS, MEDLINE, the Cochrane Central Register of Controlled Trials, and Web of Science.

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We investigated the selective excitation of localized surface plasmons by structured light. We derive selection rules using group theory and propose a fitting integral to quantify the contribution of the eigenmodes to the absorption spectra. Based on the result we investigate three nano oligomers of different symmetry (trimer, quadrumer, and hexamer) in detail using finite-difference time-domain simulations.

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The coherent evolution of a molecular quantum state during a molecule-surface collision is a detailed descriptor of the interaction potential which was so far inaccessible to measurements. Here we use a magnetically controlled molecular beam technique to study the collision of rotationally oriented ground state hydrogen molecules with a lithium fluoride surface. The coherent control nature of the technique allows us to measure the changes in the complex amplitudes of the rotational projection quantum states, and express them using a scattering matrix formalism.

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Background: Breast cancer is one of the most common malignancies in women worldwide, and one of the leading causes of cancer-related death. Programmed cell death 1 (PD-1) and its ligand (PD-L1) are key physiologic suppressors of the cytotoxic immune reaction. Some authors advocate that PD-L1 expression may help in breast cancer prognosis.

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Article Synopsis
  • The study introduces shape-invariant Bessel beams as a new option for free-space optical communications, specifically targeting orbital angular momentum (OAM).
  • These beams, created using a phase-only element on a spatial light modulator, are designed to be long-range and self-healing.
  • The research compares the performance of helical OAM beams with Bessel-like OAM beams in a 150 m outdoor optical link, revealing similar performance levels and analyzing the effects of link characteristics on modal cross-talk.
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In this paper, the electronically nonadiabatic Landau-Zener (LZ) mechanism for the vibrational relaxation v = 1 → v = 0 of NO(XΠ) in collisions with Ar(S01) is discussed. It corresponds to nonadiabatic transitions between two crossing vibronic potential energy surfaces (PESs) originating from vibrational states of the collision complex and supported by two coupled electronic PESs. The LZ rate coefficients k10LZ are calculated within the uniform Airy approach in the reaction coordinate approximation with parameters derived from ab initio PESs and an asymptotic estimation of the Franck-Condon factor in the nonadiabatic coupling region.

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Background: Distinguishing hydatidiform moles (HMs) from nonmolar specimens and the subclassification of HM are important because complete hydatidiform mole (CHM) is associated with an increased risk of development of gestational trophoblastic neoplasia. However, diagnosis based solely on morphology has poor inter-observer reproducibility. Recent studies have demonstrated that the use of p57 immunostaining improves diagnostic accuracy for CHM.

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The aim of this study was to investigate the role of the ß-adrenergic blocker bucindolol on endothelial dysfunction and pulmonary vascular remodeling in rats with pulmonary arterial hypertension (PAH). Male Wistar rats were divided into four groups: control, monocrotaline (MCT), control?+?bucindolol and monocrotaline?+?bucindolol (MCT?+?BCD). PAH was induced by an injection of monocrotaline (60?mg/kg i.

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Aims: This study aimed to investigate whether beneficial effects of thyroid hormones are comparable to those provided by the aerobic exercise training, to verify its applicability as a therapeutic alternative to reverse the pathological cardiac remodeling post-infarction.

Materials And Methods: Male rats were divided into SHAM-operated (SHAM), myocardial infarction (MI), MI subjected to exercise training (MIE), and MI who received T3 and T4 treatment (MIH) (n = 8/group). MI, MIE and MIH groups underwent an infarction surgery while SHAM was SHAM-operated.

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Pulmonary arterial hypertension (PAH) is characterized by vasoconstriction and proliferative obstruction of pulmonary vessels, which promotes a progressive increase in pulmonary vascular resistance (PVR). The effect of exercise training on oxidative stress, metabolism, and markers of nitric oxide (NO) and endothelin-1 (ET-1) was analyzed in the lung tissue of rats with PAH induced by monocrotaline (MCT).Twenty-four Wistar rats were divided into four groups (5-7 animals): sedentary control (SC), sedentary MCT (SM), trained control (TC), and trained MCT (TM).

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Rate coefficients for capture of H(j = 0,1) by H are calculated in perturbed rotor approximation, i.e., at collision energies considerably lower than Bhc (where B denotes the rotational constant of H).

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Pulmonary arterial hypertension (PAH) is characterised by an elevation in afterload imposed on the right ventricle (RV), leading to hypertrophy and failure. The autonomic nervous system (ANS) plays a key role in the progression to heart failure, and the use of beta-blockers attenuates this process. The aim of this study was to verify the role of bucindolol, aβ1-, β2- and α1-blocker, on the ANS, and its association with RV function in rats with PAH.

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Background: Distinguishing hydatidiform moles (HMs) from non-molar specimens and the subclassification of HM are important because complete hydatidiform mole (CHM) is associated with an increased risk of gestational trophoblastic neoplasia. However, diagnosis based solely on morphology has poor interobserver reproducibility. Recent studies have demonstrated that the use of p57 immunostaining improves diagnostic accuracy for CHM.

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Purpose: An open-label, noninferiority study to evaluate the impact of epoetin alfa (EPO) on tumor outcomes when used to treat anemia in patients receiving chemotherapy for metastatic breast cancer.

Methods: Women with hemoglobin ≤ 11.0 g/dL, receiving first- or second-line chemotherapy for metastatic breast cancer, were randomly assigned to EPO 40,000 IU subcutaneously once a week or best standard of care.

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We propose a new technique for laser beam shaping into a desirable beam profile by using a laser amplifier with a pump beam that has a modified intensity profile. We developed the analytical formula, which describes the transformation of the seed beam into the desired beam profile in a four level amplifiers small signal regime. We propose a numerically method to obtain the required pump intensity profile in the case where high pump power saturated the laser crystal or for three level materials.

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Tunneling corrections to Landau-Zener rate coefficients for the vibrational relaxation NO(X(2)Π, v = 1) + Ar → NO(X(2)Π, v = 0) + Ar between 300 and 2000 K are determined employing ab initio potential energy surfaces calculated by the code provided by Alexander [J. Chem. Phys.

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Bessel beams have been extensive studied to date but are always created over a finite region inside the laboratory. Means to overcome this consider multi-element refractive designs to create beams that have a longitudinal dependent cone angle, thereby allowing for a far greater quasi non-diffracting propagation region. Here we outline a generalized approach for the creation of shape-invariant Bessel-like beams with a single phase-only element, and demonstrate it experimentally with a phase-only spatial light modulator.

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Laguerre-Gaussian beams with a nonzero azimuthal index are known to carry orbital angular momentum (OAM), and are routinely created external to laser cavities. The few reports of obtaining such beams from laser cavities suffer from inconclusive evidence of the real electromagnetic field. In this Letter we revisit this question and show that an observed doughnut beam from a laser cavity may not be a pure Laguerre-Gaussian azimuthal mode but can be an incoherent sum of petal modes, which do not carry OAM.

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Background: Superior vena cava syndrome (SVCO) is caused by compression of superior vena cava and restriction of blood flow to the heart. The most common underlying condition in cancer patients is lung cancer or other malignancy expanding in the upper mediastinum. SVCO belongs to oncological emergencies and requires a prompt dia-gnostic work up and treatment.

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Article Synopsis
  • The study presents a straightforward laser setup using an opaque ring and a circular aperture to create various laser beam types, including Gaussian and Flat-top beams.
  • The ability to adjust the beam type is achieved by changing the aperture's diameter, which does not necessitate any realignment of the laser cavity.
  • The researchers used a digital laser with a spatial light modulator inside the cavity to validate their theory, successfully confirming the expected characteristics of the laser system through experiments.
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The rate coefficients for capture of charged particles by dipolar polarizable symmetric top molecules in the quantum collision regime are calculated within an axially nonadiabatic channel approach. It uses the adiabatic approximation with respect to rotational transitions of the target within first-order charge-dipole interaction and takes into account the gyroscopic effect that decouples the intrinsic angular momentum from the collision axis. The results are valid for a wide range of collision energies (from single-wave capture to the classical limit) and dipole moments (from the Vogt-Wannier and fly-wheel to the adiabatic channel limit).

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