Photoluminescence excitation spectroscopy in narrow - gap Hg₁₋x₋yCd xMnyTe

New results on infrared photoluminescence and photoluminescence excitation spectroscopy around the fundamental energy gap in Hg₁₋x₋yCdxMnyTe single crystal are presented. A very strong electron-phonon coupling influencing the optical spectra of this narrow-gap semiconductor is found. An indirect «hot exciton» absorption under participation of longitudinal optical phonons occurs to be the main absorption mechanism. It was shown, that knowledge about the excitonic processes in wide gap semiconductors also can be applied to high-quality narrow-gap materials

Cooperative Effects in the Photoluminescence of (In,Ga)As/GaAs Quantum Dot Chain Structures

Multilayer In0.4Ga0.6As/GaAs quantum dot (QD) chain samples are investigated by means of cw and time-resolved photoluminescence (PL) spectroscopy in order to study the peculiarities of interdot coupling in such nanostructures. The temperature dependence of the PL has revealed details of the confinement. Non-thermal carrier distribution through in-chain, interdot wave function coupling is found. The peculiar dependences of the PL decay time on the excitation and detection energies are ascribed to the electronic interdot coupling and the long-range coupling through the radiation field. It is shown that the dependence of the PL decay time on the excitation wavelength is a result of the superradiance effect

Deuteron-equivalent and phase-equivalent interactions within light nuclei

Background: Phase-equivalent transformations (PETs) are well-known in quantum scattering and inverse scattering theory. PETs do not affect scattering phase shifts and bound state energies of two-body system but are conventionally supposed to modify two-body bound state observables such as the rms radius and electromagnetic moments. Purpose: In order to preserve all bound state observables, we propose a new particular case of PETs, a deuteron-equivalent transformation (DET-PET), which leaves unchanged not only scattering phase shifts and bound state (deuteron) binding energy but also the bound state wave function. Methods: The construction of DET-PET is discussed; equations defining the simplest DET-PETs are derived. We apply these simplest DET-PETs to the JISP16 $NN$ interaction and use the transformed $NN$ interactions in calculations of $^3$H and $^4$He binding energies in the No-core Full Configuration (NCFC) approach based on extrapolations of the No-core Shell Model (NCSM) basis space results to the infinite basis space. Results: We demonstrate the DET-PET modification of the $np$ scattering wave functions and study the DET-PET manifestation in the binding energies of $^3$H and $^4$He nuclei and their correlation (Tjon line). Conclusions: It is shown that some DET-PETs generate modifications of the central component while the others modify the tensor component of the $NN$ interaction. DET-PETs are able to modify significantly the $np$ scattering wave functions and hence the off-shell properties of the $NN$ interaction. DET-PETs give rise to significant changes in the binding energies of $^3$H (in the range of approximately 1.5 MeV) and $^4$He (in the range of more than 9 MeV) and are able to modify the correlation patterns of binding energies of these nuclei

MOLECULAR APOPTOSIS MECHANISMS WITH UNDERLYING EXPERIMENTAL ACUTE LUNG INJURY

Background. Current data suggest systemic autoimmune activation in the pathogenesis of bronchopulmonary diseases. The imbalance in the system of pro- and anti-inflammatory cytokines is very important in immunopathogenesis. Objective. The aim of our research was to determine the caspase-3 rate in the dynamics of experimental acute lung injury and to study the relationship between their level and the number of cells carrying membrane binding TNF receptor type 1 to define the main mechanisms of cell death. Results. The analysis of the results of caspase-3 rate in lung homogenate showed that this cysteine proteinase was uniformly increasing in all experimental groups during simulating of ALI induced by administration of hydrochloric acid (p<0.001). When comparing the results of caspase course of apoptosis it was defined that, despite the progressive increase in caspase-3 rate in lung homogenate, cysteine proteinase rate in plasma did not change. The receptor mechanism of apoptosis was studied by establishing correlation relationships with the number of cells carrying membrane binding TNF type 1 (TNF-R1) receptor. A strong positive correlation relationship between the number of neutrophils with TNF-R1 and caspase-3 rate in lungs of all research groups was determined. Conclusions. The implementation of neutrophils death by apoptosis is caused by change of activity of caspase cascade effector components, such as caspase-3, in cases of ALI induced by intratracheal administration of hydrochloric acid. One of the potential mechanisms responsible for the activation of caspase course is excessive generation of active forms of oxygen and increase in the number of neutrophils carrying membrane binding TNF receptor type 1.Історія питання . В даний час дані дозволяють припустити , системне аутоімунне активації в патогенезі бронхолегеневих захворювань. Дисбаланс в системі про- та протизапальних цитокінів є дуже важливим в иммунопатогенеза. Мета. Метою нашого дослідження було визначити частоту каспаз-3 в динаміці експериментального гострого пошкодження легенів і вивчити взаємозв'язок між їх рівнем і число клітин , що несуть мембрану зв'язують TNF рецептора типу 1 , щоб визначити основні механізми клітинної смерті. результати. аналіз результатів каспаз-3 швидкості в гомогенате легких показали , що цей цістеінпротеаза рівномірно збільшується в усіх експериментальних групах під час моделювання ОПЛ , викликаного введенням соляної кислоти (р <0,001). При порівнянні результатів каспаз процесі апоптозу було визначено , що, незважаючи на поступове збільшення каспаз-3 швидкості в гомогенате легких, цистеїн швидкість протеїнази в плазмі НЕ change.The рецепторний механізм апоптозу був вивчений шляхом встановлення кореляції відносин з числом клітин , що несуть мембрану зв'язування рецептора типу 1 TNF (TNF-R1). Сильна позитивна кореляція залежність між числом нейтрофілів з TNF-R1 і каспаз-3 швидкості в легких всіх дослідних груп була визначена. Висновки. Реалізація смерті нейтрофілів шляхом апоптозу викликано зміною активності каспаз компонентів каскадів ефекторних, такі в якості каспаз-3, у випадках ОЛП індукованих трахею соляної кислоти. Одним з можливих механізмів , відповідальних за активацію каспаз курсу є надмірне утворення активних форм кисню і збільшення числа нейтрофілів , що несуть мембрану зв'язування TNF рецептора типу 1

Population of isomers in decay of the giant dipole resonance

The value of an isomeric ratio (IR) in N=81 isotones ($^{137}$Ba, $^{139}$Ce, $^{141}$Nd and $^{143}$Sm) is studied by means of the ($\gamma, n)$ reaction. This quantity measures a probability to populate the isomeric state in respect to the ground state population. In ($\gamma, n)$ reactions, the giant dipole resonance (GDR) is excited and after its decay by a neutron emission, the nucleus has an excitation energy of a few MeV. The forthcoming $\gamma$ decay by direct or cascade transitions deexcites the nucleus into an isomeric or ground state. It has been observed experimentally that the IR for $^{137}$Ba and $^{139}$Ce equals about 0.13 while in two heavier isotones it is even less than half the size. To explain this effect, the structure of the excited states in the energy region up to 6.5 MeV has been calculated within the Quasiparticle Phonon Model. Many states are found connected to the ground and isomeric states by $E1$, $E2$ and $M1$ transitions. The single-particle component of the wave function is responsible for the large values of the transitions. The calculated value of the isomeric ratio is in very good agreement with the experimental data for all isotones. A slightly different value of maximum energy with which the nuclei rest after neutron decay of the GDR is responsible for the reported effect of the A-dependence of the IR.Comment: 16 pages, 4 Fig

Magnetically controlled exciton transfer in hybrid quantum dot-quantum well nanostructures

A magnetophotoluminescence study of the carrier transfer with hybrid InAs/GaAs quantum dot(QD)-InGaAs quantum well (QW) structures is carried out where we observe an unsual dependence of the photoluminescence (PL) on the GaAs barrier thickness at strong magnetic field and excitation density. For the case of a thin barrier the QW PL intensity is observed to increase at the expense of a decrease in the QD PL intensity. This is attributed to changes in the interplane carrier dynamics in the QW and the wetting layer (WL) resulting from increasing the magnetic field along with changes in the coupling between QD excited states and exciton states in the QW and the WL

Aharonov-Bohm interference in quantum ring exciton: effects of built-in electric fields

We report a comprehensive discussion of quantum interference effects due to the finite structure of excitons in quantum rings and their first experimental corroboration observed in the optical recombinations. Anomalous features that appear in the experiments are analyzed according to theoretical models that describe the modulation of the interference pattern by temperature and built-in electric fields.Comment: 6 pages, 7 figure

Nucleon-nucleon interaction in the JJ-matrix inverse scattering approach and few-nucleon systems

The nucleon-nucleon interaction is constructed by means of the $J$-matrix version of inverse scattering theory. Ambiguities of the interaction are eliminated by postulating tridiagonal and quasi-tridiagonal forms of the potential matrix in the oscillator basis in uncoupled and coupled waves, respectively. The obtained interaction is very accurate in reproducing the $NN$ scattering data and deuteron properties. The interaction is used in the no-core shell model calculations of $^3$H and $^4$He nuclei. The resulting binding energies of $^3$H and $^4$He are very close to experimental values.Comment: Text is revised, new figures and references adde

Epidemiological pattern of community-acquired respiratory tract infections of the conscripts in the North Fleet during a vaccine-challenged period

The formation of the new military units in the North fleet is accompanied by vaccination using Exhausted diphtheria tetanus vaccine, modified. The accination coincides with periods of a rising number of army conscripts being taken ill with community-acquired infection of respiratory tracts: acute tonsillitis, acute bronchitis and community-acquired pneumonia. We need to study is to ascertain whether there is the correlation between the periods of the increase in the number of ervicemen fallen ill with community-acquired infection of respiratory tracts and the diphtheria and tetanus vaccination. The study was carried out on the North fleet conscripts who were drawn blood samples from the ulnar vein before and after the vaccination using Exhausted diphtheria tetanus vaccine, modified. The blood was examined for the presence of antibodies to diphtheria and tetanus using direct hemagglutination test. The health status of the vaccinated conscripts was under observation for 4 months, during which acute illnesses (acute tonsillitis, acute bronchitis and community-acquired pneumonia) were registered. Serologic testing demonstrated a high rate of immunological protection against diphtheria and tetanus before vaccination. After the diphtheria and tetanus vaccination, the number of conscripts, who were taken ill in the first month, was significantly higher compared to the following months. The conscripts, who fell ill, had high antibody titers against diphtheria and tetanus in the vaccine-challenged period. Vaccination of the servicemen using Exhausted diphtheria tetanus vaccine, modified, is serologically unfounded; it leads to complications such as acute tonsillitis, acute bronchitis and community-acquired pneumonia during the vaccinechallenged period especially during the first month and less considerably during the following months