55 research outputs found

    Nonlinear Optics and Quantum Entanglement of Ultra-Slow Single Photons

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    Two light pulses propagating with ultra-slow group velocities in a coherently prepared atomic gas exhibit dissipation-free nonlinear coupling of an unprecedented strength. This enables a single-photon pulse to coherently control or manipulate the quantum state of the other. Processes of this kind result in generation of entangled states of radiation field and open up new prospectives for quantum information processing

    New dinuclear cyanido complexes with amine alcohol ligand: synthesis, characterization and biotechnological application potential

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    In this study, the cyanido complexes given by the formula [Ni(Abut)Ni(CN)4]·8H2O (C1), [Cu(Abut)2Ni(CN)4]·7H2O (C2), [Zn(Abut)Ni(CN)4]·8H2O (C3) and [Cd(Abut)Ni(CN)4]·7H2O (C4) were obtained by microwave synthesis method. The powder forms of the complexes were characterized by elemental, FT-IR spectroscopy, and thermal analysis. And also antibacterial, antibiofilm and anticancer activities were investigated. The splitting stretching bands of cyanido groups in the FT-IR spectra of C1-C4 indicated the assets of terminal and end cyanido groups. The antibacterial activities of C1-C4 were tested with nine Gram negative and six Gram positive bacteria. The most efficient antibacterial activity of complexes was observed at 1000 µg/ml-1 concentration. Anticancer activity was tested using HeLa cell line and MTT test. The studied cyanide complexes have been shown to decrease the viability of HeLa cells with IC50 values 14.86, 6.5, 7.2 and 19.2 µg/ml for C1, C2, C3 and C4 complex, respectively

    Quantum-dot spin qubit and hyperfine interaction

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    We review our investigation of the spin dynamics for two electrons confined to a double quantum dot under the influence of the hyperfine interaction between the electron spins and the surrounding nuclei. Further we propose a scheme to narrow the distribution of difference in polarization between the two dots in order to suppress hyperfine induced decoherence.Comment: 12 pages, 3 figures; Presented as plenary talk at the annual DPG meeting 2006, Dresden (to appear in Advances in Solid State Physics vol. 46, 2006

    Vacuum Squeezing in Atomic Media via Self-Rotation

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    When linearly polarized light propagates through a medium in which elliptically polarized light would undergo self-rotation, squeezed vacuum can appear in the orthogonal polarization. A simple relationship between self-rotation and the degree of vacuum squeezing is developed. Taking into account absorption, we find the optimum conditions for squeezing in any medium that can produce self-rotation. We then find analytic expressions for the amount of vacuum squeezing produced by an atomic vapor when light is near-resonant with a transition between various low-angular-momentum states. Finally, we consider a gas of multi-level Rb atoms, and analyze squeezing for light tuned near the D-lines under realistic conditions.Comment: 10 pages, 6 figures; Submitted to PR

    Strongly interacting polaritons in coupled arrays of cavities

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    Observing quantum phenomena in strongly correlated many-particle systems is difficult because of the short length- and timescales involved. Exerting control over the state of individual elements within such a system is even more so, and represents a hurdle in the realization of quantum computing devices. Substantial progress has been achieved with arrays of Josephson junctions and cold atoms in optical lattices, where detailed control over collective properties is feasible, but addressing individual sites remains a challenge. Here we show that a system of polaritons held in an array of resonant optical cavities—which could be realized using photonic crystals or toroidal microresonators—can form a strongly interacting many-body system showing quantum phase transitions, where individual particles can be controlled and measured. The system also offers the possibility to generate attractive on-site potentials yielding highly entangled states and a phase with particles much more delocalized than in superfluids

    Understanding Change in Romantic Relationship Expectations of International Female Students from Turkey

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    In the light of grounded theory, the authors explored change in romantic relationship expectations of international students. Twelve female graduate students from Turkey were interviewed and several themes were identified explaining the presence and absence of change in participants’ attitudes toward romantic relationships. The findings are discussed in relation to acculturation and direction for future research is presented

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    A social psychological comparison of the Turkish elderly residing at high or low quality institutions

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    This paper aims to provide a comparison of the Turkish elderly residing at high- or low-quality institutions in terms of institutional and life satisfaction, attitudes toward institutional living, feelings of control, nature of relocation, importance attributed to different aspects of institutions, and preferences for different living conditions. In-depth interviews were carried out with 106 Turkish males and females (62-89 years) divided equally between high- and low-quality institutions from Istanbul. Compared to those from low-quality institutions, respondents from high-quality institutions reported feeling more satisfied with their lives and institutional living, having more personal control, having moved to the institution more voluntarily, and were more likely to prefer their current living environments and to attribute importance to facilities, services, physical surroundings and leisure time activities. In spite of such differences in assessments of current living environments, those residing at high-quality institutions did not seem to have significantly more positive attitudes toward institutional living in general, although there was a trend in that direction. In terms of gender differences, females reported more life satisfaction, more positive attitudes toward institutional living, more voluntary relocation, and were more likely to prefer their current living places and to attribute importance to people. Present results from the collectivistic Turkish context are discussed in reference to related findings from the more individualistic societies, as well as those concerning the community-residing elderly. (C) 1999 Academic Press

    Cytotoxic Effects of Kynurenic Acid and Quinaldic Acid in Hepatocellular Carcinoma (HepG2) Cell Line

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    Kynurenic acid (KYNA), tryptophan metabolite synthesized in the kynurenine pathway, is present in human body fluids as well as in variety of foods, herbal medicines and honeybee derived foodstuffs. KYNA is an endogenous antagonist of all ionotropic glutamate receptors. It has been found that glutamate antagonists inhibit proliferation of different human tumor cells. Quinaldic acid (QUINA), a derivative of KYNA, is also a tryptophan metabolite and shows high similarity to KYNA in physiological and pathological processes. It has been suggested that both of these endogenous substances have antiproliferative activities in colon cancer cell lines. In this study, the cytotoxic activities of KYNA and QUINA in human hepatocellular carcinoma (HepG2) cell line were investigated. HepG2 cells were exposed to different concentrations (1 µM–10 mM) of KYNA and QUINA for 24, 36 and 48 h. The cell viability was determined by MTT assay. Our results showed that KYNA and QUINA decreased the viability of HepG2cells on a dose- and time-dependent manner, and have cytotoxic effects in milimolar concentrations. To the best of our knowledge, this is the first report on cytotoxic effects of KYNA and QUINA in HepG2 cell lines. Further studies needed to explore the potential roles of KYNA and QUINA as a chemotherapeutic or chemopreventive agent in hepatocellular carcinoma

    A reliable and fast mesh-free solver for the telegraph equation

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    In the presented study, the hyperbolic telegraph equation is taken as the focus point. To solve such an equation, an accurate, reliable, and efficient method has been proposed. The developed method is mainly based on the combination of a kind of mesh-free method and an adaptive method. Multiquadric radial basis function mesh-free method is considered on spatial domain and the adaptive fifth-order Runge–Kutta method is used on time domain. The validity and the performance of the proposed method have been checked on several test problems. The approximate solutions are compared with the exact solution, it is shown that the proposed method has more preferable to the other methods in the literature. © 2022, The Author(s) under exclusive licence to Sociedade Brasileira de Matemática Aplicada e Computacional.The authors are grateful to the Editor-in-Chief and the anonymous referees for their valuable and constructive comments/suggestions to improve the original version
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