Nitric oxide synthesis and biological functions of nitric oxide released from ruthenium compounds

During three decades, an enormous number of studies have demonstrated the critical role of nitric oxide (NO) as a second messenger engaged in the activation of many systems including vascular smooth muscle relaxation. The underlying cellular mechanisms involved in vasodilatation are essentially due to soluble guanylyl-cyclase (sGC) modulation in the cytoplasm of vascular smooth cells. sGC activation culminates in cyclic GMP (cGMP) production, which in turn leads to protein kinase G (PKG) activation. NO binds to the sGC heme moiety, thereby activating this enzyme. Activation of the NO-sGC-cGMP-PKG pathway entails Ca2+ signaling reduction and vasodilatation. Endothelium dysfunction leads to decreased production or bioavailability of endogenous NO that could contribute to vascular diseases. Nitrosyl ruthenium complexes have been studied as a new class of NO donors with potential therapeutic use in order to supply the NO deficiency. In this context, this article shall provide a brief review of the effects exerted by the NO that is enzymatically produced via endothelial NO-synthase (eNOS) activation and by the NO released from NO donor compounds in the vascular smooth muscle cells on both conduit and resistance arteries, as well as veins. In addition, the involvement of the nitrite molecule as an endogenous NO reservoir engaged in vasodilatation will be described

Electrical activation of carbon in GaAs : implantation temperature effects

Carbon was implanted into GaAs at the energy of 1 MeV with doses between 131013 and 2 31015 cm22 at temperatures of 80 K, nominal room temperature (RT), and 300 °C. A markedly higher electrical activation was obtained in the samples implanted at 80 K compared to those implanted at RT or 300 °C, attaining a maximum hole concentration of 231019 cm23. The redistribution of the C profile during rapid thermal annealing at temperatures from 700 to 950 °C for 10 s was found negligible, independently of the implantation temperature. Similar improvements in the electrical properties were also verified in samples implanted at 80 K with a lower energy of 60 keV. We consider that despite the light mass of C ions, the reduced dynamic annealing at 80 K allows the accumulation of an abundance of As vacancies, which assist the C activation as a p-type dopant

A New Approach For Interexaminer Reliability Data Analysis On Dental Caries Calibration

Objectives: a) to evaluate the interexaminer reliability in caries detection considering different diagnostic thresholds and b) to indicate, by using Kappa statistics, the best way of measuring interexaminer agreement during the calibration process in dental caries surveys. Methods: Eleven dentists participated in the initial training, which was divided into theoretical discussions and practical activities, and calibration exercises, performed at baseline, 3 and 6 months after the initial training. For the examinations of 6-7-year-old schoolchildren, the World Health Organization (WHO) recommendations were followed and different diagnostic thresholds were used: WHO (decayed/missing/filled teeth - DMFT index) and WHO + IL (initial lesion) diagnostic thresholds. The interexaminer reliability was calculated by Kappa statistics, according to WHO and WHO+IL thresholds considering: a) the entire dentition; b) upper/lower jaws; c) sextants; d) each tooth individually. Results: Interexaminer reliability was high for both diagnostic thresholds; nevertheless, it decreased in all calibration sections when considering teeth individually. Conclusion: The interexaminer reliability was possible during the period of 6 months, under both caries diagnosis thresholds. However, great disagreement was observed for posterior teeth, especially using the WHO+IL criteria. Analysis considering dental elements individually was the best way of detecting interexaminer disagreement during the calibration sections.156480485Assaf, A.V., Meneghim, M.C., Zanin, L., Mialhe, F.L., Pereira, A.C., Ambrosano, G.M.B., Assessment of different methods for diagnosing dental caries in epidemiological surveys (2004) Community Dent Oral Epidemiol, 32, pp. 418-425Assaf, A.V., Meneghim, M.C., Zanin, L., Cortellazzi, K.L., Pereira, A.C., Ambrosano, G.M.B., Effect of different diagnostic thresholds on dental caries calibration (2006) J Public Health Dentistry, 66, pp. 17-22Assaf, A.V., Meneghim, M.C., Zanin, L., Tengan, C., Pereira, A.C., Effect of different diagnostic thresholds for dental caries calibration - a 12 month evaluation (2006) Community Dent Oral Epidemiol, 34, pp. 213-219Brasil, da Saúde, M., SB Brasil (2002) Projeto, , Condições de saúde bucal da população brasileira:, Brasília, DF;, 2003 2004Cohen, J.A., Coefficient of agreement for nominal scales (1960) Education and Psychological Measurement, 20, pp. 37-46Fyffe, H.E., Deery, C., Nugent, Z.J., Nuttall, N.M., Pitts, N.B., Effect of diagnostic threshold on the validity and reliability of epidemiological caries diagnosis using the Dundee Selectable Threshold Method for caries diagnosis (DSTM) (2000) Community Dent Oral Epidemiol, 28, pp. 42-51Landis, J.R., Koch, G.G., The measurement of observer agreement for categorical data (1977) Biometrics, 33, pp. 159-174Marthaler, T.M., Changes in dental caries 1953-2003 (2004) Caries Res, 38, pp. 173-181Mitropoulos, C.M., Lennon, M.A., Worthington, H.V., A national calibration exercise for the British Association for the Study of Community Dentistry regional examiners (1990) Community Dent Health, 7, pp. 179-187Ministério da Saúde, (1988) Levantamento epidemiológico em saúde bucal: Brasil, Zona Urbana, 1986, , Brasília: Centro de Documentação, Ministério da Saúde;Nuttall, N.M., Paul, J.W., The analysis of inter-dentist agreement in caries prevalence studies (1985) Community Dent Health, 2, pp. 123-128Nyvad, B., Machiulskiene, V., Baelum, V., Construct and predictive validity of clinical caries diagnostic criteria assessing lesion activity (2003) J Dent Res, 82, pp. 117-122Nyvad, B., Machiulskiene, V., Baelum, V., Reliability of a new caries diagnostic system differentiating between active and inactive caries lesions (1999) Caries Res, 33, pp. 252-260Peres, M.A., Traebert, J., Marcenes, W., Calibração de examinadores para estudos epidemiológicos de cárie dentária (2001) Cad Saude Publica, 17, pp. 153-159Pine, C.M., Pitts, N.B., Nugent, Z.J., British Association for the Study of Community Dentistry (BASCD) guidance on the statistical aspects of training and calibration of examiners for surveys of child dental health. A BASCD coordinated dental epidemiology programme quality standard (1997) Community Dent Health, 14 (SUPPL. 1), pp. 18-29Sim, J., Wright, C.C., The kappa statistic in reliability studies: Use, interpretation, and sample size requirements (2005) Phys Ther, 85, pp. 257-268Oral health surveys (1997) Basic methods, , World Health Organization, 4th ed. Geneva: WHO

Rheological and Textural Analyses

LA/P/0140/2020Biobased raw materials like natural polysaccharides are increasingly sought by the cosmetic industry for their valuable properties. Such biodegradable and usually non-cytotoxic biopolymers are commonly used in skin-care products as rheological modifiers, bioemulsifiers and/or bioactive ingredients. FucoPol is a natural polysaccharide with reported biocompatibility, emulsion-forming and stabilizing capacity, shear-thinning behavior and bioactivity (e.g., antioxidant capacity, wound healing ability) that potentiate its utilization in skin-care products. In this study, olive oil and α-tocopherol containing emulsions were stabilized with FucoPol. Although the presence of α-tocopherol negatively impacted the emulsions’ stability, it increased their emulsification index (EI). Moreover, FucoPol outperformed the commercial emulsifier Sepigel® 305, under the tested conditions, with higher EI and higher stability under storage for 30 days. The formulation of FucoPol-based emulsions with olive oil and α-tocopherol was studied by Response Surface Methodology (RSM) that allowed the definition of the ingredients’ content to attain high emulsification. The RSM model established that α-tocopherol concentration had no significant impact on the EI within the tested ranges, with optimal emulsification for FucoPol concentration in the range 0.7–1.2 wt.% and olive oil contents of 20–30 wt.%. Formulations with 25 wt.% olive oil and either 0.5 or 2.0 wt.% α-tocopherol were emulsified with 1.0 wt.% or 0.7 wt.% FucoPol, respectively, resulting in oil-in-water (O/W) emulsions. The emulsions had similar shear-thinning behavior, but the formulation with higher FucoPol content displayed higher apparent viscosity, higher consistency, as well as higher firmness, adhesiveness and cohesiveness, but lower spreadability. These findings show FucoPol’s high performance as an emulsifier for olive oil/α-tocopherol, which are supported by an effective impact on the physicochemical and structural characteristics of the emulsions. Hence, this natural polysaccharide is a potential alternative to other emulsifiers.publishersversionpublishe

Models of electron transport in single layer graphene

The main features of the conductivity of doped single layer graphene are analyzed, and models for different scattering mechanisms are presented.Comment: 15 pages. Submitted to the Proceedings of the ULTI symposium on Quantum Phenomena and Devices at Low Temperatures, Espoo, Finland, to be published in the Journ. of Low. Temp. Phy

Oscillating Solitons Pinned to a Nonmagnetic Impurity in Layered Antiferromagnets

We argue that an oscillatory motion of impurity-pinned solitons may occur in layered antiferromagnetic compounds. The characteristic frequencies of these modes, that may be detected by resonance or inelastic neutron scattering, are estimated analytically and depend on the soliton sizes and types .Comment: 11 pages, 1 figur

Spatial antibunching of photons with parametric down-conversion

The theoretical framework behind a recent experiment by Nogueira et. al. [Phys. Rev. Lett. 86}, 4009 (2001)] of spatial antibunching in a two-photon state generated by collinear type II parametric down-conversion and a birefringent double-slit is presented. The fourth-order quantum correlation function is evaluated and shown to violate the classical Schwarz-type inequality, ensuring that the field does not have a classical analog. We expect these results to be useful in the rapidly growing fields of quantum imaging and quantum information.Comment: 5 pages, 3 figures. Minor changes made, accepted for publication in PR

A Green's function approach to transmission of massless Dirac fermions in graphene through an array of random scatterers

We consider the transmission of massless Dirac fermions through an array of short range scatterers which are modeled as randomly positioned $\delta$- function like potentials along the x-axis. We particularly discuss the interplay between disorder-induced localization that is the hallmark of a non-relativistic system and two important properties of such massless Dirac fermions, namely, complete transmission at normal incidence and periodic dependence of transmission coefficient on the strength of the barrier that leads to a periodic resonant transmission. This leads to two different types of conductance behavior as a function of the system size at the resonant and the off-resonance strengths of the delta function potential. We explain this behavior of the conductance in terms of the transmission through a pair of such barriers using a Green's function based approach. The method helps to understand such disordered transport in terms of well known optical phenomena such as Fabry Perot resonances.Comment: 22 double spaced single column pages. 15 .eps figure

Klein tunneling in graphene: optics with massless electrons

This article provides a pedagogical review on Klein tunneling in graphene, i.e. the peculiar tunneling properties of two-dimensional massless Dirac electrons. We consider two simple situations in detail: a massless Dirac electron incident either on a potential step or on a potential barrier and use elementary quantum wave mechanics to obtain the transmission probability. We emphasize the connection to related phenomena in optics, such as the Snell-Descartes law of refraction, total internal reflection, Fabry-P\'erot resonances, negative refraction index materials (the so called meta-materials), etc. We also stress that Klein tunneling is not a genuine quantum tunneling effect as it does not necessarily involve passing through a classically forbidden region via evanescent waves. A crucial role in Klein tunneling is played by the conservation of (sublattice) pseudo-spin, which is discussed in detail. A major consequence is the absence of backscattering at normal incidence, of which we give a new shorten proof. The current experimental status is also thoroughly reviewed. The appendix contains the discussion of a one-dimensional toy model that clearly illustrates the difference in Klein tunneling between mono- and bi-layer graphene.Comment: short review article, 18 pages, 14 figures; v3: references added, several figures slightly modifie