Quantum dots as optimized chiral emitters for photonic integrated circuits

Chiral coupling, which allows directional interactions between quantum dots (QDs) and photonic crystal waveguide modes, holds promise for enhancing the functionality of quantum photonic integrated circuits. Elliptical polarizations of QD transitions offer a considerable enhancement in directionality. However, in epitaxial QD fabrication, the lack of precise control over lateral QD positions still poses a challenge in achieving efficient chiral interfaces. Here, we present a theoretical analysis in which we propose to optimize the polarization of a QD emitter against the spatially averaged directionality and demonstrate that the resulting emitter offers a considerable technological advantage in terms of the size and location of high-directionality areas of the waveguide as well as their overlap with the regions of large Purcell enhancement, thereby improving the scalability of the device. Moreover, using $\mathbf{\mathit{k}}\cdot\mathbf{\mathit{p}}$ modeling, we demonstrate that the optimal elliptical polarization can be achieved for neutral exciton transitions in a realistic QD structure. Our results present a viable path for efficient chiral coupling in QD-based photonic integrated circuits, to a large extent overcoming the challenges and limitations of the present manufacturing technology.Comment: Some text modifications in the Introduction, references added, typos corrected, Fig. 7 updated, and the title change

Changes in Motor Skills of Children who Train Sports Swimming at the Initial Stage of School Education (in an Annual Training Cycle)

This paper presents an empirical approach to the changes in motor skills of children who train sports swimming at the initial stage of school education in an annual training cycle. Swimming belongs to the disciplines in which training starts at the age of 6-7. The proper selection of candidates to train certain disciplines is a complex process as they should be chosen from a large population of children, both girls and boys, having specific somatic and motor characteristics which, developed in the long-term, will enable them to achieve sports mastery. The aim of the research was to define which changes in motor skills occur in girls who train sports Aim: swimming in an annual training cycle. The Subject group consisted of 85 girls aged 7 who attended four elementary schools in Szczecin, Poland. 36 of them belonged to the Swimmers group and they were all members of the Municipal Swimming Club (MKP) in Szczecin. The Control group consisted of 49 girls who attended the same elementary schools. All subjects took part in two examinations (carried out in the school year 2009/2010. Physical ability tests were conducted in gyms. Motor skills were assessed with EUROFIT Test Battery which is the most reliable and accurate tool according to scientific research. The research revealed changes in both groups (Sw, C) in terms of all eight tests. Examination II proved statistically significant improvement of results in both groups (Sw, C) in comparison to Examination I. Changes between Examination I and Examination II results were most visible in the Swimmers groups in terms of balance, agility, static strength, functional strength and agility run. Changes between Examination I and Examination II were similar in both groups (Sw, C) in terms of speed of limb movement, explosive strength and torso strength. Progressive changes in motor skill of subjects are a positive phenomenon in the physical development of a child. Swimming training resulted significantly in positive changes in terms of motor skills of subject who were at the initial stage of swimming trainings, compared to their non-training peers. Participation in organized, regular sports classes results in the development of motor (physical) skills of children

Mapping the Interaction Network of Key Proteins Involved in Histone mRNA Generation: A Hydrogen/Deuterium Exchange Study

Histone pre-mRNAs are cleaved at the 3′ end by a complex that contains U7 snRNP, the FLICE-Associated Huge protein (FLASH) and Histone pre-mRNA Cleavage Complex (HCC) consisting of several polyadenylation factors. Within the complex, the N-terminus of FLASH interacts with the N-terminus of the U7 snRNP protein Lsm11 and together they recruit the HCC. FLASH through its distant C-terminus independently interacts with the C-terminal SANT/Myb-like domain of Nuclear Protein, Ataxia-Telangiectasia locus (NPAT), a transcriptional co-activator required for expression of histone genes in S-phase. To gain structural information on these interactions, we used mass spectrometry to monitor hydrogen/deuterium (H/D) exchange in various regions of FLASH, Lsm11 and NPAT alone or in the presence of their respective binding partners. Our results indicate that the FLASH-interacting domain in Lsm11 is highly dynamic, while the more downstream region required for recruiting the HCC exchanges deuterium slowly and likely folds into a stable structure. In FLASH, a stable structure is adopted by the domain that interacts with Lsm11 and this domain is further stabilized by binding Lsm11. Notably, both H/D exchange experiments and in vitro binding assays demonstrate that Lsm11, in addition to interacting with the N-terminal region of FLASH, also contacts the C-terminal SANT/Myb-like domain of FLASH, the same region that binds NPAT. However, while NPAT stabilizes this domain, Lsm11 causes its partial relaxation. These competing reactions may play a role in regulating histone gene expression in vivo

Plasma modification of carbon coating produced by RF CVD on oxidized NiTi shape memory alloy under glow-discharge conditions

Our previous work has shown that for cardiac applications, combining low-temperature plasma oxidation with an amorphous carbon coating (a-C:N:H type) constitutes a prospective solution. In this study, a short-term modification by low-temperature oxygen plasma is proposed as an example and a method for shaping the topography and surface energy of the outer amorphous carbon coating, produced via the Radio-Frequency Chemical Vapour Deposition (RFCVD) method on NiTi alloy oxidized under glow-discharge conditions. This treatment alters the chemical composition of the outer zone of the surface layer. A slight increase is also noted in the surface roughness at the nanoscale. The contact angles were shown to increase by about 20% for water and 30% for diiodomethane, while the surface free energy decreased by ca. 11%. The obtained results indicate that even short-term contact with low-temperature plasma can shape the surface properties of the carbon coating, an outcome which shows potential in terms of its use in medical applications

Metabolic syndrome — a new definition and management guidelines

The joint position paper by Polish Society of Hypertension, Polish Society for the Treatment of Obesity, Polish Lipid Association, Polish Association for Study of Liver, Polish Society of Family Medicine, Polish Society of Lifestyle Medicine, Division of Prevention and Epidemiology Polish Cardiac Society, “Club 30” Polish Cardiac Society, and Division of Metabolic and Bariatric Surgery Society of Polish Surgeons Reviewers: Agnieszka Olszanecka, Krzysztof J. Filipia

Nuclear Import and Export Signals of Human Cohesins SA1/STAG1 and SA2/STAG2 Expressed in Saccharomyces cerevisiae

Abstract Background: Human SA/STAG proteins, homologues of the yeast Irr1/Scc3 cohesin, are the least studied constituents of the sister chromatid cohesion complex crucial for proper chromosome segregation. The two SA paralogues, SA1 and SA2, show some specificity towards the chromosome region they stabilize, and SA2, but not SA1, has been shown to participate in transcriptional regulation as well. The molecular basis of this functional divergence is unknown. Methodology/Principal Findings: In silico analysis indicates numerous putative nuclear localization (NLS) and export (NES) signals in the SA proteins, suggesting the possibility of their nucleocytoplasmic shuttling. We studied the functionality of those putative signals by expressing fluorescently tagged SA1 and SA2 in the yeast Saccharomyces cerevisiae. Only the Nterminal NLS turned out to be functional in SA1. In contrast, the SA2 protein has at least two functional NLS and also two functional NES. Depending on the balance between these opposing signals, SA2 resides in the nucleus or is distributed throughout the cell. Validation of the above conclusions in HeLa cells confirmed that the same N-terminal NLS of SA1 is functional in those cells. In contrast, in SA2 the principal NLS functioning in HeLa cells is different from that identified in yeast and is localized to the C-terminus. Conclusions/Significance: This is the first demonstration of the possibility of non-nuclear localization of an SA protein. The reported difference in the organization between the two SA homologues may also be relevant to their partially divergent functions. The mechanisms determining subcellular localization of cohesins are only partially conserved between yeast and human cells

Efficiency of revised constructions of protective layers of the subgrade

Geotechnical examinations of the subgrade are conducted before its rehab, repair or upbringing works. Due to variability of parameters of the subgrade soil over time, and limited scope of such examinations, the geotechnical model of the subgrade, identified based on test results, is inevitably characterised by uncertainty. The actual soil conditions are identified as part of geotechnical checks performed during repair or upbringing building works. Using these test results, subgrade soil parameters are then checked for conformance with their design values. In case any discrepancy is found, or the ensuing inadequacy of the design construction of protective layers in the actual soil conditions, appropriate revised constructions are designed and implemented. This paper describes and compared the five most frequently used types of revised constructions of protective layers of the subgrade, whose parameters are adjusted to the prevailing local soil conditions. For each type of construction, its material requirements were analysed, as well as its required volume of earth works and its execution unit cost were identified. Upon this basis, the discussed protective layer revised constructions' efficiency and their recommended application conditions were determined, depending on their prevailing actual soil conditions

Ocena szkolnej oferty turystycznej przez uczniów szczecińskich szkół średnich

Zeszyty Naukowe Uniwersytetu Szczecińskiego. Nr 444