1.55-μm mode-locked quantum-dot lasers with 300 MHz frequency tuning range

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 106, 031114 (2015) and may be found at https://doi.org/10.1063/1.4906451.Passive mode-locking of two-section quantum-dot mode-locked lasers grown by metalorganic vapor phase epitaxy on InP is reported. 1250-μm long lasers exhibit a wide tuning range of 300 MHz around the fundamental mode-locking frequency of 33.48 GHz. The frequency tuning is achieved by varying the reverse bias of the saturable absorber from 0 to −2.2 V and the gain section current from 90 to 280 mA. 3 dB optical spectra width of 6–7 nm leads to ex-facet optical pulses with full-width half-maximum down to 3.7 ps. Single-section quantum-dot mode-locked lasers show 0.8 ps broad optical pulses after external fiber-based compression. Injection current tuning from 70 to 300 mA leads to 30 MHz frequency tuning.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, BauelementeEC/FP7/EU/264687/Postgraduate Research on Photonics as an Enabling Technology/PROPHE

Wider-frequency combs generation, noise reduction, and repetition rate tuning in quantum-dot mode-locked lasers

We describe the technique allowing for generation of low-noise wider frequency combs and pulses of shorter duration in quantum-dot mode-locked lasers. We compare experimentally noise stabilization techniques in semiconductor modelocked lasers. We discuss the benefits of electrical modulation of the laser absorber voltage (hybrid mode-locking), combination of hybrid mode-locking with optical injection seeding from the narrow linewidth continues wave master source and optical injection seeding of two coherent sidebands separated by the laser repetition rate

Polymorphisms of the GSTT1 and GSTM1 genes in women of central Serbia: Absence of association with uterine myoma

Since glutathione S-transferase (GST) enzymes are involved in cellular protection, we aimed to determine the distribution of GSTT1 and GSTM1 null genotypes in women in central Serbia in order to assess the risk of development of uterine myoma. The study consisted of 34 clinically diagnosed uterine myoma patients and 35 healthy control women. Analyses of GST polymorphism were carried out by multiplex PCR. Our results showed no significant differences in the GSTT1 and GSTM1 null genotypes between the patients and controls. Using the GSTT1 positive/GSTM1 positive combination as reference, there was no statistically significant risk of uterine myoma with the combination of GSTT1 null and GSTM1 null genotypes. We conclude that polymorphism of both GSTT1 and GSTM1 genes, alone or in combination, did not present the main risk for uterine myoma in women from central Serbia.[Projekat Ministarstva nauke Republike Srbije, br. III41010 i br. ON 175103

Chirurgische eingriffe am parodontalen Geweben in red Retromolaren region

U radu je prikazana hirurška terapija dubokih gingivalnih džepova u retromolarnom regionu, kao i džepova onih zuba, koji se nalaze neposredno do bezubih viličnih regiona. Ovaj hirurški zahvat, izveden je na 23 bolesnika. Diskutovano je o prednostima i nedostacima ove metode.Surgical treatment of deep retromolar pockets and pockets next to edentulous ridges has been described in this paper. This kind of periodontal surgery was carried out on 23 patients, having such problems. The advantages and disadvantages of this type of treatment have been discussed.In dieser Arbeit wurde das chirurgische Heilen der tiefen Zahnfleischtaschen in den retromolaren Regionen, und von Taschen an Zähnen gegenüber den zahnlosen Kieferegionen vorgenommen. Diese Art der chirurgischen Eingriffe wurde an über 23 Kranken durchgeführit. Über Vorteile so auch Nachteile diese Methode wird diskutiert

Pressure effects on the transport coefficients of Ba(Fe1-xCox)2As2

We report the temperature dependence of the resistivity and thermoelectric power under hydrostatic pressure of the itinerant antiferromagnet BaFe2As2 and the electron-doped superconductor Ba(Fe0.9Co0.1)2As2. We observe a hole-like contribution to the thermopower below the structural-magnetic transition in the parent compound that is suppressed in magnitude and temperature with pressure. Pressure increases the contribution of electrons to transport in both the doped and undoped compound. In the 10% Co-doped sample, we used a two-band model for thermopower to estimate the carrier concentrations and determine the effect of pressure on the band structure

Hepatoprotective Effect of Mixture of Dipropyl Polysulfides in Concanavalin A-Induced Hepatitis

The main biologically active components of plants belonging to the genus Allium, responsible for their biological activities, including anti-inflammatory, antioxidant and immunomodulatory, are organosulfur compounds. The aim of this study was to synthetize the mixture of dipropyl polysulfides (DPPS) and to test their biological activity in acute hepatitis. C57BL/6 mice were administered orally with DPPS 6 h before intravenous injection of Concanavalin A (ConA). Liver inflammation, necrosis and hepatocytes apoptosis were determined by histological analyses. Cytokines in liver tissue were determined by ELISA, expression of adhesive molecules and enzymes by RT PCR, while liver mononuclear cells were analyzed by flow cytometry. DPPS pretreatment significantly attenuated liver inflammation and injury, as evidenced by biochemical and histopathological observations. In DPPS-pretreated mice, messenger RNA levels of adhesion molecules and NADPH oxidase complex were significantly reduced, while the expression of SOD enzymes was enhanced. DPPS pretreatment decreased protein level of inflammatory cytokines and increased percentage of T regulatory cells in the livers of ConA mice. DPPS showed hepatoprotective effects in ConA-induced hepatitis, characterized by attenuation of inflammation and affection of Th17/Treg balance in favor of T regulatory cells and implicating potential therapeutic usage of DPPS mixture in inflammatory liver diseases

The clay minerals from greda deposit

The term "clay" refers to natural materials composed of fine minerals, which in their composition contain water molecules, which give it the property of plasticity, which is lost by drying processes. The basic physical and chemical characteristics of clay are low permeability, the possibility of cation exchange, thermal structural stability, swelling processes. These characteristic properties appear as a consequence of the crystal structure, in which the layers of SiO4, tetrahedra, extend infinitely in two dimensions. In this paper are presented the basic structural and crystallochemical properties of clay from Greda deposit

Stability of quantum-dot excited-state laser emission under simultaneous ground-state perturbation

The impact of ground state amplification on the laser emission of In(Ga)As quantum dot excited state lasers is studied in time-resolved experiments. We find that a depopulation of the quantum dot ground state is followed by a drop in excited state lasing intensity. The magnitude of the drop is strongly dependent on the wavelength of the depletion pulse and the applied injection current. Numerical simulations based on laser rate equations reproduce the experimental results and explain the wavelength dependence by the different dynamics in lasing and non-lasing sub-ensembles within the inhomogeneously broadened quantum dots. At high injection levels, the observed response even upon perturbation of the lasing sub-ensemble is small and followed by a fast recovery, thus supporting the capacity of fast modulation in dual-state devices

Potential preservation of dental pulp stem cells

Dental pulp stem cells (DPSCs) as postnatal stem cells have recently been described. They are clonogenic cells, capable for self-renewal with high proliferative potential. Their multilineage potential and plasticity enables their differentiation into different kind of cells, such as osteoblasts, chondrocytes, adipocytes, muscle cells, neural cells, odontoblasts, cementoblasts and ameloblasts. DPSCs are an important human stem cells source, especially in patients who lost their chance for umbilical cord blood isolation and preservation. As these cells became useful for tissue engineering and cell therapy, proper mode of their preservation also became important. The most important points in the cryopreservation and recovery procedure are: growth phase of harvested cells, number of cells, the proper cryopreservative concentration and serum concentration. The cryopreservation process includes the following general components: harvesting of the cells, addition of cryopreservative, the freezing procedure, the thawing procedure and assessment of the viability prior to transplantation. There is no single and perfect cryopreservation method. Further investigations should be regarding capability of DPSCs and their differentiated cells to recover and restart proliferation, differentiation and new tissue production for therapeutic use after cryopreservation

A crisis of protection and safe passage: violence experienced by migrants/refugees travelling along the Western Balkan corridor to Northern Europe.

BACKGROUND: Pushed by ongoing conflicts and pulled by the desire for a better life, over one million migrants/refugees transited Balkan countries and arrived in Europe during 2015 and early 2016. To curb this influx, European countries instituted restrictive migration policies often characterized by building of razor-wire border fences and border closures. Among migrants/refugees who received mental health care in Serbia while travelling through Balkan countries to Northern Europe, we assessed the prevalence and patterns of violent events experienced including physical trauma. METHODS: A mixed methods study among migrants/refugees attending mobile mental health clinics run by Médecins sans Frontières (MSF) between July 2015 and June 2016, in Serbia - a main transit hub to European countries. Clinics were conducted according to MSF guidelines by experienced psychologists who were supported by cultural mediators. The main outcome measures were violent events and associated physical trauma. RESULTS: Of 992 migrants/refugees attending MSF mental health clinics, the majority (72%) were from Syria and Afghanistan and included vulnerable groups (14%) such as unaccompanied minors and pregnant women. The most frequent mental health symptoms/signs were anxiety (29%) and adjustment reactions (26%). Of the 992 migrants/refugees, 270 (27%) had experienced violent events during their journey. Signs of physical trauma due to acts of violence were seen in 223(22%) of the 992 individuals, 144 (65%) being perpetrated by State authorities and involving women (11%) and children (13%). Border closures along the Balkan route were associated with a dramatic decrease in registered migrants/refugee arrivals in Serbia. Conversely, among those that made it across the borders, an increasing linear trend in reported violent events was observed at MSF mental health clinics (X2 for linear trend, P <0 · 001). Qualitative evidence corroborated with quantitative findings. CONCLUSIONS: Nearly one-in-three migrants/refugees seen in MSF clinics experienced violent events including physical trauma along their journey. State authorities, including those in European countries were the perpetrators in over half of such events which were associated with border closures. There is "a crisis of protection and safe passage" which needs to change towards one of respect for the principles of international human rights and refugee law