Spin-coated Tin-doped NiO thin films for third order nonlinear optical applications

A self-made spin-coater was employed to deposit pure and Sn doped nickel oxide thin films on glass substrates. The tin doping impact on the structural, linear and nonlinear optical properties of the spin-coated NiO thin films was studied. The XRD analysis showed that undoped and Sn doped NiO thin films have a cubic structure and are preferentially oriented along the (200) direction. The increase of doping concentration leads to a modification in the values of certain parameters such as the crystallite size and the structural strain as well as affecting the nonlinear optical properties of the doped nickel oxide thin films. The values of the third order nonlinear optical susceptibility, found to be between 2.25 × 10−21 m2/V2 and 3.13 × 10−21 m2/V2, were obtained and analyzed depending on the concentration of the doping

Comparison of structural, morphological, linear and nonlinear optical properties of NiO thin films elaborated by Spin-Coating and Spray Pyrolysis

The paper reports on a comparative study of nickel oxide thin films prepared via two different elaboration methods spin-coating and spray pyrolysis. The structure and the surface topography of the NiO thin films have been studied by X-ray diffraction and the atomic force microscope. The optical properties of the deposited films were characterized with the analysis of the experimentally recorded optical transmittance data in the spectral wavelength range of 300–850 nm, via a JENWAY6715 UV–vis spectrophotometer. To complete the comparison, the third order nonlinear optical susceptibility was determined from the third harmonic generation experiment, which in turn were explored by the rotational Maker fringe technique using the beam of Nd:YAG laser at 1064 nm in picoseconds regime. The present work is aimed to exhibit the influence of the elaboration method on the physical properties through analyzing the obtained experimental results

Spin-coated nickel doped cadmium sulfide thin films for third harmonic generation applications

In the current study, different percentages of Nickel (0%, 2%, 4% and 6%) doped CdS thin films have been deposited on glass substrates by the sol-gel spin-coating technique. Before performing the nonlinear optical studies, the structural, morphological and optical properties were examined as a function of Ni doping concentration through the XRD, SEM, AFM and UV–vis spectrometry, respectively. According to the XRD patterns, all films are polycrystalline and the incorporation of Ni does not change qualitatively the crystalline phase of CdS. The Ni doping affects the surface morphology of the CdS thin films which is indicated by scanning electron microscopy and atomic force microscopy images. The band gap was determined via the equation related to the absorption coefficient. It\u27s deduced that the optical band-gap values increased from 2.35 eV to 2.41 eV depending on Ni content. Though, the nonlinear optical properties were determined based on the measurements of the third harmonic generation (THG) using the rotational Maker fringe technique. The results showed that the third order nonlinear optical susceptibilities oscillate between 5.40 × 10−21 m2/V2 for CdS:Ni (2%) and 4.98 × 10−21 m2/V2 for CdS:Ni (6%) while the pure CdS one falls inward, with a value of 5.09 × 10−21 m2/V2

Effects of culture conditions on acetic acid production by bacteria isolated from Ivoirian fermenting cocoa (Theobroma cacao L.) beans

Objectives: This study investigates the acidification capacity under various culture conditions of high acetic acid producer AAB strains previously isolated from Ivoirian cocoa beans fermentation.Methodology and Results: Effect of culture conditions was studied in agar medium and acid production was monitored by measuring the clear halo diameter during incubation. All tested strains showed acetic acid production at 30, 35 and 40 °C. Moreover, at initial concentration 0.1 - 0.4 %, lactic and citric acids stimulated acidification capacity of these strains with increase rate ranged from 50 to 100 % while acetic acid reduced this capacity. In addition, maximum acetic acid production capacity was obtained for strains 123 D; 56 AB and 49 D at 8 % ethanol initial concentration.Conclusions and application of findings: This study shows that all tested strains are able to produce acetic acid under certain culture conditions similar to cocoa fermentation stress. However, cocoa fermentation assay is needed to better estimate the performance of selected strains.Keywords: Acetic acid bacteria, acetic acid production, Cocoa fermentation, culture condition

In vitro seeds germination and seedling growth of cashew (Anacardium occidentale L.)

In Côte d’Ivoire, the yield of cashew nuts is low. This situation has led to the use of improved clonal-based material for the expansion or establishment of new plantations. To obtain a mass propagation of such elite materials, application of tissue culture becomes very important. However, it is difficult to obtain viable explants derived from mature plants developing in field because of high concentrations of disinfectants required for surface sterilization. Explants excised from in vitro seedlings are therefore the most suitable for the micropropagation of cashew. The objective of this study was to identify the type of seeds suitable for in vitro germination and plantlets development. Seeds without shell with entire cotyledons (SWSEC), seeds without shells with half cotyledons (SWSHC) and the embryonic axis (EA) were placed on the basal medium of Murashige and Skoog (MS) without any plant growth regulators. The final rate of germination ranged from 75 to 95 %, the time to have 50 % germination and the average germination time were statistically identical with the three types of seeds. Higher plants (7cm) with larger numbers of leaves, which are more vigorous were obtained with SWSHC. This type of seeds is therefore more suitable provide seedling used as explant sources for themicropropagation of the cashew tree.Key words : Anacardium occidentale ; germination ; micropropagatio

Optimization and diagnostic of nonlinear optical features of π-conjugated benzodifuran-based derivatives

The nonlinear optical parameters of benzodifuran-based derivatives obtained by a green approach are determined under picosecond laser irradiation. The guest–host polymeric films were prepared on the basis of benzodifuran derivatives incorporated into PMMA. The optical absorption spectra of benzodifuran-based compounds in films and solutions were analyzed and their SHG and THG measurements were performed by means of the Maker fringe technique in transmission scheme using the output beam of a mode-locked Nd:YAG/YVO4 laser generating at 1064 nm with 30 ps pulse duration. The compounds with asymmetrical structure and increased π-conjugated chains have shown the highest SHG response of the order of 10−13 m V−1. Z-scan measurements have been carried out at 532 nm and the values of nonlinear optical refractive indexes and absorption coefficients were defined and revealed negative nonlinear refraction and positive nonlinear absorption

The Chikungunya Epidemic on La Réunion Island in 2005–2006: A Cost-of-Illness Study

For a long time, studies of chikungunya virus infection have been neglected, but since its resurgence in the south-western Indian Ocean and on La Réunion Island, this disease has been paid greater amounts of attention. The economic and social impacts of chikungunya epidemics are poorly documented, including in developed countries. This study estimated the cost-of-illness associated with the 2005–2006 chikungunya epidemics on La Réunion Island, a French overseas department with an economy and health care system of a developed country. “Cost-of-illness” studies measure the amount that would have been saved in the absence of a disease. We found that the epidemic incurred substantial medical expenses estimated at €43.9 million, of which 60% were attributable to direct medical costs related, in particular, to expenditure on medical consultations (47%), hospitalization (32%) and drugs (19%). The costs related to care in ambulatory and hospitalized cases were €90 and €2000 per case, respectively. This study provides the basic inputs for conducting cost-effectiveness and cost-benefit evaluations of chikungunya prevention strategies

Damage of woven composite under tensile and shear stress using infrared thermography and micrographic cuts

Infrared thermography was used to study damage developing in woven fabrics. Two different experiments were performed, a ±45° tensile test and a rail shear test. These two different types of tests show different damage scenarios, even if the shear stress/strain curves are similar. The ±45° tension test shows matrix hardening and matrix cracking whereas the rail shear test shows only matrix hardening. The infrared thermography was used to perform an energy balance, which enabled the visualization of the portion of dissipated energy caused by matrix cracking. The results showed that when the resin is subjected to pure shear, a larger amount of energy is stored by the material, whereas when the resin is subjected to hydrostatic pressure, the main part of mechanical energy is dissipated as heat

On the Treatment of Airline Travelers in Mathematical Models

The global spread of infectious diseases is facilitated by the ability of infected humans to travel thousands of miles in short time spans, rapidly transporting pathogens to distant locations. Mathematical models of the actual and potential spread of specific pathogens can assist public health planning in the case of such an event. Models should generally be parsimonious, but must consider all potentially important components of the system to the greatest extent possible. We demonstrate and discuss important assumptions relative to the parameterization and structural treatment of airline travel in mathematical models. Among other findings, we show that the most common structural treatment of travelers leads to underestimation of the speed of spread and that connecting travel is critical to a realistic spread pattern. Models involving travelers can be improved significantly by relatively simple structural changes but also may require further attention to details of parameterization

Impact of Chikungunya Virus Infection on Health Status and Quality of Life: A Retrospective Cohort Study

BACKGROUND:Persistent symptoms, mainly joint and muscular pain and depression, have been reported several months after Chikungunya virus (CHIKV) infection. Their frequency and their impact on quality of life have not been compared with those of an unexposed population. In the present study, we aimed to describe the frequency of prolonged clinical manifestations of CHIKV infection and to measure the impact on quality of life and health care consumption in comparison with that of an unexposed population, more than one year after infection. METHODOLOGY/PRINCIPAL FINDINGS:In a retrospective cohort study, 199 subjects who had serologically confirmed CHIKV infection (CHIK+) were compared with 199 sero-negative subjects (CHIK-) matched for age, gender and area of residence in La Réunion Island. Following an average time of 17 months from the acute phase of infection, participants were interviewed by telephone about current symptoms, medical consumption during the last 12 months and quality of life assessed by the 12-items Short-Form Health Survey (SF-12) scale. At the time of study, 112 (56%) CHIK+ persons reported they were fully recovered. CHIK+ complained more frequently than CHIK- of arthralgia (relative risk = 1.9; 95% confidence interval: 1.6-2.2), myalgia (1.9; 1.5-2.3), fatigue (2.3; 1.8-3), depression (2.5; 1.5-4.1) and hair loss (3.8; 1.9-7.6). There was no significant difference between CHIK+ and CHIK- subjects regarding medical consumption in the past year. The mean (SD) score of the SF-12 Physical Component Summary was 46.4 (10.8) in CHIK+ versus 49.1 (9.3) in CHIK- (p = 0.04). There was no significant difference between the two groups for the Mental Component Summary. CONCLUSIONS/SIGNIFICANCE:More than one year following the acute phase of infection, CHIK+ subjects reported more disabilities than those who were CHIK-. These persistent disabilities, however, have no significant influence on medical consumption, and the impact on quality of life is moderate