85 research outputs found
Polarization sensitive spectroscopy of charged Quantum Dots
We present an experimental and theoretical study of the polarized
photoluminescence spectrum of single semiconductor quantum dots in various
charge states. We compare our high resolution polarization sensitive spectral
measurements with a new many-carrier theoretical model, which was developed for
this purpose. The model considers both the isotropic and anisotropic exchange
interactions between all participating electron-hole pairs. With this addition,
we calculate both the energies and polarizations of all optical transitions
between collective, quantum dot confined charge carrier states. We succeed in
identifying most of the measured spectral lines. In particular, the lines
resulting from singly-, doubly- and triply- negatively charged excitons and
biexcitons. We demonstrate that lines emanating from evenly charged states are
linearly polarized. Their polarization direction does not necessarily coincide
with the traditional crystallographic direction. It depends on the shells of
the single carriers, which participate in the recombination process.Comment: 11 pages, 9 figures. Revised versio
Data-sharing as a quid pro quo of co-regulation in the EU
The paper focuses on the defining of the co-regulation of national and supranational legal regimes’ features of data-sharing in the digital platforms’ functioning on the example of the EU’s practice with a special attention to the disintegration process of Brexit. Data-sharing is one of the most appropriate spheres to demonstrate specific traits of digital platforms — the cross-border character of their operation. This demands quid pro quo interaction of the national and supranational regulatory regimes, filling the gap associated with the lack of international regulation and the inability to harmonize law. We begin with the theoretical characterization of information and personal data, the right to privacy, and classifications of interventions in private life. The EU has been chosen as an example, acting as a flagship of interaction of national and supranational legal orders in relation to the co-regulation of cross-border data-sharing in digital platforms. Interaction of the EU on the principle of quid pro quo, based on the practice of making decisions on adequacy, is considered in the context of Brexit and the relevant law-making practice of the UK. The discussion is complemented by examples of similar EU relations with South Korea and the United States. Based on the analysis, the authors conclude that the EU supranational legal order has a high degree of influence on the national legislation of third countries, which contributes to the constant development of regulation in the sphere and the strengthening of international integration
Role of hepcidin in the development of anemia in patients with rheumatoid arthritis
Chronic disease anemia (CDA) diagnosed in many patients with rheumatoid arthritis (RA) was described in the early 1970s. As earlier noted, iron metabolic disturbances in CDA are its diagnostic feature and the discovery of hepcidin, an iron-regulatory acute-phase protein, could largely clarify an association between the immune mechanism of impaired iron homeostasis and the development of CDA. Objective: to define the role of hepcidin in the differential diagnosis of CDA and true iron deficiency in patients with RA. Subjects and methods. The investigation enrolled 76 patients with RA (1987 ACR criteria) admitted to the Research Institute of Rheumatology, Russian Academy of Medical Sciences, to be treated. The patients were divided into two groups. A study group comprised anemic patients (n = 47). The WHO criteria for anemia were considered to be hemoglobin (Hb) levels of below 120 g/l for women and below 130 g/l for men. A control group consisted of non-anemic patients (n = 29). The anemic and non-anemic patients were matched for age (45.5±14.3 and 49.8±14.3 years, respectively) and disease duration (2 months to 20 years) (p > 0.05). Iron metabolic parameters, such as serum iron, total serum iron-binding capacity (TSIBC), iron transferrin saturation (ITS), transferrin receptors, and serum ferritin (SF), were studied and the level of hepcidin prohormone was estimated by direct enzyme immunoassay (Hepcidin Prohormone Enzyme Immunoassay Kit, IBL, Germany) in all the patients to be analyzed. Cytokines, such as interleukin 6, tumor necrosis factor-а) were determined by enzyme immunoassay (Bender MedSystems, Austria). The Institute’s differential diagnostic algorithm involving SF, TSIBC, and ITS was used to diagnose iron deficiency. The diagnosis was based on two stages of estimating iron values: isolated iron-deficiency anemia (IDA) was diagnosed if SF was below the normal value (< 40 μg/l). If the patient had SF of μ40 μg/l with a simultaneous rise of TSIBC above the normal level (> 70 μg/l) and a drop of ITS (> 20%), he/she might be suspected as having the mixed genesis of anemia, in which both iron deficiency and CDA are detectable. The other patients could be diagnosed as having isolated CDA. Results. The study has established that irrespective of the hemoglobin level, the content of serum hepcidin prohormone in the examined patients with RA averaged 89.2±65.1 pg/ml and was much higher than that in donors (64.9+21.6 pg/ml; р < 0.05). An analysis of the blood biochemical parameters characterizing iron metabolism showed that, whether they were anemic or non-anemic, the patients with RA, as compared with donors, were found to have an elevated level of SF that is an acute-phase indicator and reflects the high activity of an inflammatory process. To rule out IDA, the anemic patients with RA were subdivided into 3 subgroups according to the differential diagnostic algorithm. Subgroup 1 included patients with isolated CDA (n = 13 patients (28% of those in the study group)); Subgroup 2 consisted of 17 (32%) patients with anemia of mixed genesis (CDA ± IDA), and Subgroup 3 comprised 17 patients with IDA. An analysis of the clinical and laboratory parameters in RA independent of the nature of anemia demonstrated that only the patients with isolated CDA had significantly higher mean values of hepcidin prohormone (120.3±56.1 pg/ml) as compared to the control group (90.3±37.9 pg/ml) and RA patients with iron deficiency (both isolated IDA and that of mixed genesis). The same subgroup had a higher inflammatory RA activity characterized by the highest values of DAS 28, C-reactive protein, and SF. Conclusion. Hepcidin is a negative regulator of iron metabolism and may be used for the differential diagnosis of CDA and true iron deficiency in patients with RA
A Novel Acyl-CoA Beta-Transaminase Characterized from a Metagenome
BACKGROUND: Bacteria are key components in all ecosystems. However, our knowledge of bacterial metabolism is based solely on the study of cultivated organisms which represent just a tiny fraction of microbial diversity. To access new enzymatic reactions and new or alternative pathways, we investigated bacterial metabolism through analyses of uncultivated bacterial consortia. METHODOLOGY/PRINCIPAL FINDINGS: We applied the gene context approach to assembled sequences of the metagenome of the anaerobic digester of a municipal wastewater treatment plant, and identified a new gene which may participate in an alternative pathway of lysine fermentation. CONCLUSIONS: We characterized a novel, unique aminotransferase that acts exclusively on Coenzyme A (CoA) esters, and proposed a variant route for lysine fermentation. Results suggest that most of the lysine fermenting organisms use this new pathway in the digester. Its presence in organisms representative of two distinct bacterial divisions indicate that it may also be present in other organisms
The Relational Impact of Multiple Sclerosis: An Integrative Review of the Literature Using a Cognitive Analytic Framework
This integrative literature review uses cognitive analytic therapy (CAT) theory to examine the impact of a chronic illness, multiple sclerosis (MS), on relationships and mental health. Electronic searches were conducted in six medical and social science databases. Thirty-eight articles met inclusion criteria, and also satisfied quality criteria. Articles revealed that MS-related demands change care needs and alter relationships. Using a CAT framework, the MS literature was analysed, and five key patterns of relating to oneself and to others were identified. A diagrammatic formulation is proposed that interconnects these patterns with wellbeing and suggests potential “exits” to improve mental health, for example, assisting families to minimise overprotection. Application of CAT analysis to the literature clarifies relational processes that may affect mental health among individuals with MS, which hopefully will inform how services assist in reducing unhelpful patterns and improve coping. Further investigation of the identified patterns is needed
The MHD nature of ionospheric wave packets excited by the solar terminator
We obtained the first experimental evidence for the magnetohydrodynamic (MHD)
nature of ionospheric medium-scale travelling wave packets (MSTWP). We used
data on total electron content (TEC) measurements obtained at the dense
Japanese network GPS/GEONET (1220 stations) in 2008-2009. We found that the
diurnal, seasonal and spectral MSTWP characteristics are specified by the solar
terminator (ST) dynamics. MSTWPs are the chains of narrow-band TEC oscillations
with single packet's duration of about 1-2 hours and oscillation periods of
10-20 minutes. Their total duration is about 4--6 hours. The MSTWP spatial
structure is characterized by a high degree of anisotropy and coherence at the
distance of more than 10 wavelengths. The MSTWP direction of travelling is
characterized by a high directivity regardless of seasons. Occurrence rate of
daytime MSTWPs is high in winter and during equinoxes. Occurrence rate of
nighttime MSTIDs has its peak in summer. These features are consistent with
previous MS travelling ionosphere disturbance (TID) statistics obtained from
630-nm airglow imaging observations in Japan. In winter, MSTWPs in the northern
hemisphere are observed 3-4 hours after the morning ST passage. In summer,
MSTWPs are detected 1.5-2 hours before the evening ST occurrence at the point
of observations, at the moment of the evening ST passage in the
magneto-conjugate point. Both the high Q-factor of oscillatory system and
synchronization of MSTWP occurrence with the solar terminator passage at the
point of observations and in the magneto-conjugate area testify the MHD nature
of ST-excited MSTWP generation. The obtained results are the first experimental
evidence for the hypothesis of the ST-generated ion sound waves.Comment: 12 pages, 3 figure
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