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We report on the application of a static (dc) electric field in the plume region during the pulsed Nd doped yttrium aluminum garnet laser deposition (PLD) of tetrahedral amorphous carbon (ta-C) films in vacuum ambient (pressure=10-4–10-3 Pa), where the working pressure is exclusively due to ablation vapor. This approach is strikingly different from the plasma- or ion-beam-assisted PLD because the mean free path at this pressure is by far longer than the target to substrate distance. Thus, the electric field interacts with individual ionized species invoking ion acceleration and gas-phase reactions among different ionized species. These phenomena are clearly dependent on the laser wavelength (first, second, or third harmonic, λ=1064, 532, and 355 nm, respectively) used for the ablation. We found that the application of the electric field causes surface smoothing (the roughness decreases from about 1 to 0.4 nm) and faster deposition rate (from about 2 to 7 nm/min) for the second and third harmonics. In addition, the phenomena are less intense in the case of the first harmonic due to the low concentration of ionized species in the plume. In addition, in the case of PLD using λ=532 nm, the electric field improves the film’s density (from 2.60 to 2.95 g/cm3). The correlations found are discussed in terms of the ablated species and the deposition mechanisms of the ta-C. [ABSTRACT FROM AUTHOR]

The structural properties of copper selenide (CuxSe), formed as a secondary phase on the surface of CuGaSe2 films grown under Cu-rich conditions on GaAs (100) substrates, were studied by micro-Raman spectroscopy. Raman bands at 45 and 263 cm-1, observed on crystallites dispersed on the CuGaSe2 film, are in agreement with the Raman modes of CuSe and Cu2Se. Polarization- and angular-dependent micro-Raman measurements reveal that the CuxSe-crystallites are grown with a preferential orientation on the CuGaSe2 surface. [ABSTRACT FROM AUTHOR]

Raman scattering and photoluminescence (PL) emission of Cu[sub x]Ga[sub y]Se[sub 2] thin films, grown by metalorganic chemical vapor deposition (MOCVD) on GaAs (100) and by physical vapor deposition (PVD) on Glass/Mo substrates, were studied at room and low temperatures as a function of composition. Line width changes of Raman bands in the temperature range 20–300 K indicate the formation of a more disordered Cu[sub x]Ga[sub y]Se[sub 2] phase with increasing Ga content. It is most likely that Raman bands observed at 193 and 199 cm-1 in the Ga-rich samples at low temperatures are associated with defect-related interface modes. The intensity increase of these bands and the photoluminescence intensity enhancement may be correlated to an increase in defect concentration in the Ga-rich phase. The radiative recombination in defect-rich Ga-rich samples with a higher degree of disorder apparently supports the PL emission. The observed changes are more pronounced in MOCVD than in PVD grown films. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The structural and optical properties of nitrogenated amorphous carbon films, grown by rf-magnetron sputtering on silicon substrates, were studied by Raman and photoluminescence (PL) spectroscopy as a function of the nitrogen concentration and the substrate bias voltage V[sub b]. For films deposited with V[sub b]=10 V, the photoluminescence emission was most intense at nitrogen concentrations in the carrier gas of 25% (75% Ar), while the intensity ratio I(D)/I(G) of the Raman bands of disordered graphite (D band) and graphite (G band) partially substituted by nitrogen exhibited a minimum simultaneously observed with a minimum of G-band frequency and a maximum of G-band width. Changes in spectral characteristics of Raman scattering at a concentration of 25% (≅30 at %) are indicative of an increase of sp³-bonded fraction and disorder. PL-enhancement coincides, in this case, with structural changes and is probably correlated to the substitution of nitrogen in the tetrahedraly bonded amorphous matrix. In the case of films deposited in a pure nitrogen atmosphere, N[sub 2] = 100%, no significant PL-intensity changes appeared to exist between films deposited at low positive (10 V) and highly negative (-200 V) substrate bias. After several months of sample storage in air, samples grown at negative V[sub b] were found to preserve their structural and optical properties, while films grown at positive bias (V[sub b]=10) and nitrogen concentrations in the carrier gas above 70% (≅40 at %) delaminated. [ABSTRACT FROM AUTHOR]

Vibrational relaxation of HCl(v=1) has been measured in mixtures with H2, HD, and D2 in the temperature range between 300 and 140 K using laser-induced fluorescence. Relaxation in mixtures with n-H2 and with hydrogen enriched with its para modification is a pure vibration–translation, rotation (V–T,R) process. In mixtures with HD and D2 both vibration–vibration (V–V) and V–T,R relaxation rates could be determined separately. [ABSTRACT FROM AUTHOR]

Presents a Raman and photoluminescence study, on silicon (Si) quantum wires fabricated on crystalline silicon (100). In-depth look at the splitting of the Raman phonon; Comparison of the Raman spectrum of silicon nanowires with the Raman spectrum of virgin crystalline silicon; Examination of the polarization dependence of the photoluminescence emission.

Drawing on Aaker’s brand equity model and Keller’s brand engagement concept and building on the sponsorship between a professional basketball club and a software company, this study examined how sport sponsorship affects brand equity and purchase behavior of the sponsor’s product. Data from 222 survey respondents were collected and analyzed using structural equation modeling techniques. The results provided evidence that perceived quality and brand engagement impact brand loyalty and purchase behavior of fans toward the sponsor’s product. Perceived fit between sponsor and sponsee and team identification were found to influence significantly sponsor’s brand equity constructs. The study extends Aaker’s model in the sport sponsorship context and highlights the influential role of perceived quality and brand engagement on driving sport team fans to form brand loyalty and purchase sponsor’s product. [ABSTRACT FROM PUBLISHER]

Background and purpose Although the first mutation associated with Parkinson's disease ( PD) was identified several years ago in the alpha-synuclein ( SNCA) gene in families of Greek and Italian ancestry, a more systematic study of this and other known PD mutations has not been performed in the Greek population. Methods A genetic analysis in 111 familial or sporadic with early-onset (≤50 years, EO) PD patients was performed for the presence of the A53T SNCA mutation. In separate subgroups of these patients, further mutations in the SNCA, LRRK2, Parkin, PINK1 and DJ-1 genes were searched for. Additionally, a subgroup of familial cases was analysed for mutations in the glucocerebrosidase ( GBA) gene. Results In total, five patients (4.5% of our whole population) were identified with the A53T SNCA mutation, two with a heterozygote dosage mutation and one with a heterozygote point mutation in the Parkin gene, and seven patients (10.3% of our familial cohort) with GBA gene mutations. Conclusions The A53T mutation in the SNCA gene, although uncommon, does represent a cause of PD in the Greek population, especially of familial EOPD with autosomal dominant inheritance. GBA mutations in the familial cohort tested here were as common as in a cohort of sporadic cases previously examined from the same centres. For the remainder of the genes, genetic defects that could definitively account for the disease were not identified. These results suggest that further Mendelian traits that lead to PD in the Greek population remain to be identified. [ABSTRACT FROM AUTHOR]

What is known and objective The relative effectiveness and safety profile of the treatments with marketing authorization for relapsing multiple sclerosis ( MS) are not well known because randomized controlled trials with head-to-head comparisons between these treatments do not exist. Thus, a network of multiple-treatments meta-analysis was performed using four clinical outcomes: 'patients free of relapse', 'patients without disease progression', 'patients without MRI progression' and 'patients with adverse events'. Methods Randomized controlled trials ( RCTs) on MS were systematically searched in PubMed and Cochrane Central Register of Controlled Trial. The network analysis performed pairwise comparisons between the marketed treatments (Betaferon 250mcg, Avonex 30mcg, Rebif 44mcg, Rebif 22mcg, Aubagio 7 mg, Aubagio 14 mg, Copaxone 20 mg, Tysabri 300 mg, Gilenya 0·5 mg and Novantrone 12 mg/m2) using direct and indirect analyses. Results and discussion The analysis included 48 articles, involving 20 455 patients with MS. The direct analysis showed better response for more than one outcome for Gilenya compared with Avonex ('patients free of relapse' and 'patients without MRI progression') and for Betaferon compared with Avonex ('patients without disease progression' and 'patients without MRI progression'). The indirect analysis indicated that Tysabri may have better relative effectiveness compared with the other treatments for two outcomes: 'patients free of relapse' and 'patients without MRI progression'. Regarding 'patients with adverse events', no data were available for all comparisons to make fair inferences. What is new and conclusion This was an attempt, for the first time, to compare the efficacy and safety profile of existing approved treatments for relapsing MS. Although some treatments have shown better response, the results of the network analysis should be interpreted with caution because of the lack of RCTs with head-to-head comparisons between treatments. [ABSTRACT FROM AUTHOR]

Objective To assess the interaction of the MTHFR C677T polymorphism with changes in lipid and glucose metabolism effected by oral hormone replacement therapy (HRT) in postmenopausal women. Methods In this open-label, prospective, interventional study, parameters of lipid and glucose metabolism, as well as homocysteine, were assessed in 97 postmenopausal women at baseline and 1 year after the initiation of HRT. Participants were stratified into three subgroups, according to the MTHFR C677T polymorphism (wild-type: CC genotype; heterozygous: CT genotype; homozygous for the mutant variable: TT genotype). Results The TT genotype was associated with an elevation of total and low density lipoprotein (LDL) cholesterol, while CT and CC genotypes were associated with a reduction of total cholesterol and LDL cholesterol after 1 year of HRT ( p = 0.032 for total cholesterol and p = 0.002 for LDL cholesterol). Women with the TT genotype had higher glucose levels in contrast to women with the CC genotype who had lower glucose levels after 1 year of HRT ( p = 0.011). Additionally, CC carriers under HRT had a significant elevation of apolipoprotein A1 levels ( p = 0.018), contrarily to CT and TT genotypes. Conclusion While HRT was associated with favorable changes in lipid and metabolic parameters in carriers of the CC genotype, this effect was not evident in carriers of the T allele. The MTHFR C677T polymorphism may modify the effect of HRT on lipid and metabolic parameters in postmenopausal women. [ABSTRACT FROM AUTHOR]

In fluid mechanics, topology optimization is used for designing flow passages, connecting predefined inlets and outlets, with optimal performance based on selected criteria. In this article, the continuous adjoint approach to topology optimization in incompressible ducted flows with heat transfer is presented. A variable porosity field, to be determined during the optimization, is the means to define the optimal topology. The objective functions take into account viscous losses and the amount of heat transfer. Turbulent flows are handled using the Spalart–Allmaras model and the proposed adjoint is exact,i.e.the adjoint to the turbulence model equation is formulated and solved, too. This is an important novelty in this article which extends the porosity-based method to account for heat transfer flow problems in turbulent flows. In problems such as the design of manifolds, constraints on the outlet flow direction, rates and mean outlet temperatures are imposed. [ABSTRACT FROM AUTHOR]

SUMMARY Robust design problems in aerodynamics are associated with the design variables, which control the shape of an aerodynamic body, and also with the so-called environmental variables, which account for uncertainties. In this kind of problems, the set of design variables, which leads to optimal performance, taking into account possible variations in the environmental variables, is sought. One of the possible ways to solve this problem is by means of the second-order second-moment approach, which requires first-order and second-order derivatives of the objective function with respect to the environmental variables. Should the minimization problem be solved using a gradient-based method, algorithms for the computation of up to third-order sensitivity derivatives (twice with respect to the environmental variables and once with respect to the shape controlling design variables) must be devised. In this paper, a combination of the continuous adjoint variable method and direct differentiation to compute the third-order sensitivities is proposed. This is shown to be the most efficient among all alternative methods provided that the environmental variables are much less than the design ones. Apart from presenting the method formulation, this paper focuses on the assessment of the so-computed up-to third-order mixed derivatives through comparison with costly finite-difference schemes. To this end, the robust design of a two-dimensional duct is performed. Then, using the validated method, the robust design of a two-dimensional cascade airfoil is demonstrated. Although both cases are handled as inverse design problems, the method can be extended to other objective functions or three-dimensional problems in a straightforward manner. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Upon certain network events, such as node or link failures, IP routers need to update their affected routing table entries. During the period between the failure occurrence and the installation of the updated entries (on the line cards), the network traffic is lost when forwarded by routers that are still using old entries. Indeed, current IP routers do not involve network traffic information during this unordered update process. The consequence is more packet losses compared to a process that would order these entries based on local traffic information. In this paper, we model and predict network traffic passing through an IP router and define two dynamic heuristics in order to reduce the packet loss resulting from routing table updates. AutoRegressive Integrated Moving Average (ARIMA)-Generalized AutoRegressive Conditional Heteroskedasticity (GARCH) traffic models are used in combination with heuristics that dynamically sort the routing entries and improve the low-level routing table update process. In a realistic simulation environment, we show that this setup can result into a clear decrease of packet loss, depending on i) the network traffic model, ii) the applied heuristic, and iii) the network traffic aggregation level. [ABSTRACT FROM AUTHOR]

Recent work has focused on cell transplantation as a therapeutic option following ischemic stroke, based on animal studies showing that cells transplanted to the brain not only survive, but also lead to functional improvement. Neural degeneration after ischemia is not selective but involves different neuronal populations, as well as glial and endothelial cell types. In models of stroke, the principal mechanism by which any improvement has been observed, has been attributed to the release of trophic factors, possibly promoting endogenous repair mechanisms, reducing cell death and stimulating neurogenesis and angiogenesis. Initial human studies indicate that stem cell therapy may be technically feasible in stroke patients, however, issues still need to be addressed for use in human subjects. [ABSTRACT FROM AUTHOR]

Cardiopulmonary resuscitation (CPR) after the induction of cardiac arrest (CA) has been studied in mice and rats. The anatomical and physiological parameters of the cardiopulmonary system of these two species have been defined during experimental studies and are comparable with those of humans. Moreover, these animal models are more ethical to establish and are easier to manipulate, when compared with larger experimental animals. Accordingly, the effects of successful CPR on the function of vital organs, such as the brain, have been investigated because damage to these vital organs is of concern in CA survivors. Furthermore, the efficacy of several drugs, such as adrenaline (epinephrine), vasopressin and nitroglycerin, has been evaluated for use in CA in these small animal models. The purpose of these studies is not only to increase the rate of survival of CA victims, but also to improve their quality of life by reducing damage to their vital organs after CA and during CPR. [ABSTRACT FROM AUTHOR]

We determined the prevalence of overweight and obesity in young Greek men in 2006 and examined variations related to their place of residence and educational level. Body height and weight were measured in 2568 conscripts of the Greek army, aged 19–26 years. The calculated body mass index (BMI, kg m−2) was correlated to their socio-demographic characteristics, i.e. level of education and place of residence (urban or rural). Overweight and obesity were defined according to the World Health Organization classification. Mean BMI (standard deviation) of the conscripts was 24.7 (4.2). The prevalence of overweight (30 > BMI ≥ 25 kg m−2) was 28.5% and correlated positively with a higher educational level, whereas the prevalence of obesity (BMI ≥ 30 kg m−2) was 10.4% and correlated positively with a lower educational level. Our data were compared with those of similar studies performed in the years 1969: BMI 23.8 (1.4) ( P < 0.0001) and 1990: BMI 23.8 (2.9) ( P < 0.0001), showing a positive secular trend for BMI in Greek conscripts in the last 16 years. In conclusion, we documented an alarmingly high prevalence of overweight and obesity among young Greek men. [ABSTRACT FROM AUTHOR]

A new continuous adjoint formulation for the optimization of cascade aerofoils with minimum total pressure losses, i.e. an objective function which has never been used before along with the continuous adjoint, is presented. To support a steepest descent algorithm, the adjoint method is used to compute the gradient of the objective function with respect to the design variables. The function is defined as the difference in total pressure between the inlet to and the outlet from the cascade. In contrast to other known continuous adjoint approaches in aerodynamics (such as inverse designs based on target pressure distributions or drag-lift optimization for isolated aerofoils), where the functional is defined over the parameterized solid walls, the present functional consists of integrals over the inlet/outlet boundaries only. To cope with this particular situation, the method of characteristics is used to impose inlet/outlet adjoint boundary conditions. It is worth noting that the objective function gradient is expressed as an integral over the solid walls. The minimization of losses in linear and peripheral compressor cascades, constrained by the desirable flow turning and the minimum allowed blade thickness, are demonstrated. [ABSTRACT FROM AUTHOR]