Laser surfasse patterning using a Michelson interferometer and a femtosecond laser radiation

We report on a simple method to obtain surface gratings using a Michelson interferometer and femtosecond laser radiation. In the optical setup used, two parallel laser beams are generated using a beam splitter and then focused using the same focusing lens. An interference pattern is created in the focal plane of the focusing lens, which can be used to pattern the surface of materials. The main advantage of this method is that the optical paths difference of the interfering beams is independent of the distance between the beams. As a result, the fringes period can be varied without a need for major realignment of the optical system and the time coincidence between the interfering beams can be easily monitored. The potential of the method was demonstrated by patterning surface gratings with different periods on titanium surfaces in air.

Desenvolvimento de ferramentas e provetes para o ensaio Thick Adherend Shear Test (TAST).

As estruturas coladas são geralmente projetadas para que o adesivo seja essencialmente sujeito a esforços de corte, pois neste tipo de solicitação o adesivo apresenta melhores caraterísticas mecânicas. A avaliação do comportamento ao corte pode ser realizada com o adesivo no estado maciço ou como camada fina em juntas adesivas. Os métodos que permitem avaliar o comportamento ao corte, quer para o adesivo, quer para as juntas, são: o ensaio Iosipescu ou V-Notched beam shear method, o ensaio de borboleta ou Notched plate shear method (Arcan), o ensaio de torsão, o ensaio de tração numa junta de sobreposição simples e o ensaio Thick Adherend Shear Test (TAST). Os ensaios Arcan e Iosipescu, tal como o ensaio de torção, podem ser realizados em provetes de adesivo maciço ou em juntas. O ensaio de torção é pouco utilizado, porque a aplicação do esforço de corte exige dispositivos e equipamentos de ensaios complexos. Os ensaios Arcan e Iosipescu utilizam provetes com entalhes e podem introduzir alguma dificuldade na medição precisa das deformações. O ensaio de tração numa junta de sobreposição simples é um dos métodos mais usados para caraterizar uma junta adesiva, porque é um método simples, as juntas são de fácil fabrico e pode ser realizado em máquinas universais de ensaios mecânicos. Neste ensaio os aderentes estão sujeitos a uma solicitação de tração, enquanto a camada de adesivo está sujeita a esforços de corte combinados com esforços de arrancamento. Os esforços de arrancamento resultam da própria geometria da junta na qual existe um desalinhamento das forças de tração, mesmo quando são colocados calços (reguladores de espessura) nos locais de amarração. O ensaio TAST é dos mais populares para obtenção das propriedades ao corte, uma vez que tanto as ferramentas de ensaio como o fabrico dos provetes são relativamente simples. Este ensaio é realizado em junta sendo os substratos espessos e de aço que, devido à sua elevada rigidez, contribuem para um esforço de corte praticamente puro no adesivo. Neste trabalho realizou-se o projeto e a fabricação das ferramentas, gabarit e substratos necessários para a execução de provetes TAST e ensaios utilizando diferentes adesivos.

Development of paper-based color test-strip for drug detection in aquatic environment: Application to oxytetracycline

The wide use of antibiotics in aquaculture has led to the emergence of resistant microbial species. It should be avoided/minimized by controlling the amount of drug employed in fish farming. For this purpose, the present work proposes test-strip papers aiming at the detection/semi-quantitative determination of organic drugs by visual comparison of color changes, in a similar analytical procedure to that of pH monitoring by universal pH paper. This is done by establishing suitable chemical changes upon cellulose, attributing the paper the ability to react with the organic drug and to produce a color change. Quantitative data is also enabled by taking a picture and applying a suitable mathematical treatment to the color coordinates given by the HSL system used by windows. As proof of concept, this approach was applied to oxytetracycline (OXY), one of the antibiotics frequently used in aquaculture. A bottom-up modification of paper was established, starting by the reaction of the glucose moieties on the paper with 3-triethoxysilylpropylamine (APTES). The so-formed amine layer allowed binding to a metal ion by coordination chemistry, while the metal ion reacted after with the drug to produce a colored compound. The most suitable metals to carry out such modification were selected by bulk studies, and the several stages of the paper modification were optimized to produce an intense color change against the concentration of the drug. The paper strips were applied to the analysis of spiked environmental water, allowing a quantitative determination for OXY concentrations as low as 30 ng/mL. In general, this work provided a simple, method to screen and discriminate tetracycline drugs, in aquaculture, being a promising tool for local, quick and cheap monitoring of drugs.

Diffusion characteristics of ethylene glycol in skeletal muscle

Part of the optical clearing study in biological tissues concerns the determination of the diffusion characteristics of water and optical clearing agents in the subject tissue. Such information is sufficient to characterize the time dependence of the optical clearing mechanisms—tissue dehydration and refractive index (RI) matching. We have used a simple method based on collimated optical transmittance measurements made from muscle samples under treatment with aqueous solutions containing different concentrations of ethylene glycol (EG), to determine the diffusion time values of water and EG in skeletal muscle. By representing the estimated mean diffusion time values from each treatment as a function of agent concentration in solution, we could identify the real diffusion times for water and agent. These values allowed for the calculation of the correspondent diffusion coefficients for those fluids. With these results, we have demonstrated that the dehydration mechanism is the one that dominates optical clearing in the first minute of treatment, while the RI matching takes over the optical clearing operations after that and remains for a longer time of treatment up to about 10 min, as we could see for EG and thin tissue samples of 0.5 mm.

FACTORS ASSOCIATED TO ADHERENCE TO DIFFERENT TREATMENT SCHEMES WITH MEGLUMINE ANTIMONIATE IN A CLINICAL TRIAL FOR CUTANEOUS LEISHMANIASIS

The favorable outcome of the treatment of a disease is influenced by the adherence to therapy. Our objective was to assess factors associated with adherence to treatment of patients included in a clinical trial of equivalence between the standard and alternative treatment schemes with meglumine antimoniate (MA) in the treatment of cutaneous leishmaniasis (CL), in the state of Rio de Janeiro. Between 2008 and 2011, 57 patients with CL were interviewed using a questionnaire to collect socioeconomic data. The following methods were used for adherence monitoring: counting of vial surplus, monitoring card, Morisky test and modified Morisky test (without the question regarding the schedule); we observed 82.1% (vial return), 86.0% (monitoring card), 66.7% (Morisky test) and 86.0% (modified Morisky test) adherence. There was a strong correlation between the method of vial counting and the monitoring card and modified Morisky test. A significant association was observed between greater adherence to treatment and low dose of MA, as well as with a lower number of people sleeping in the same room. We recommend the use of the modified Morisky test to assess adherence to treatment of CL with MA, because it is a simple method and with a good performance, when compared to other methods.

Optical clearing mechanisms characterization in muscle

Optical immersion clearing is a technique that has been widely studied for more than two decades and that is used to originate a temporary transparency effect in biological tissues. If applied in cooperation with clinical methods it provides optimization of diagnosis and treatment procedures. This technique turns biological tissues more transparent through two main mechanisms — tissue dehydration and refractive index (RI) matching between tissue components. Such matching is obtained by partial replacement of interstitial water by a biocompatible agent that presents higher RI and it can be completely reversible by natural rehydration in vivo or by assisted rehydration in ex vivo tissues. Experimental data to characterize and discriminate between the two mechanisms and to find new ones are necessary. Using a simple method, based on collimated transmittance and thickness measurements made from muscle samples under treatment, we have estimated the diffusion properties of glucose, ethylene glycol (EG) and water that were used to perform such characterization and discrimination. Comparing these properties with data from literature that characterize their diffusion in water we have observed that muscle cell membrane permeability limits agent and water diffusion in the muscle. The same experimental data has allowed to calculate the optical clearing (OC) efficiency and make an interpretation of the internal changes that occurred in muscle during the treatments. The same methodology can now be used to perform similar studies with other agents and in other tissues in order to solve engineering problems at design of inexpensive and robust technologies for a considerable improvement of optical tomographic techniques with better contrast and in-depth imaging.

Spray coating of oxide and chalcogenide semiconductor layers for TFT application

This work documents the deposition and optimization of semiconductor thin films using chemical spray coating technique (CSC) for application on thin-film transistors (TFTs), with a low-cost, simple method. CSC setup was implemented and explored for industrial application, within Holst Centre, an R&D center in the Netherlands. As zinc oxide had already been studied within the organization, it was used as a standard material in the initial experiments, obtaining typical mobility values of 0.14 cm2/(V.s) for unpatterned TFTs. Then, oxide X layer characteristics were compared for films deposited with CSC at 40°C and spin-coating. The mobility of the spin-coated TFTs was 103 cm2/(V.s) higher, presumably due to the lack of uniformity of spray-coated film at such low temperatures. Lastly, tin sulfide, a relatively unexplored material, was deposited by CSC in order to obtain functional TFTs and explore the device’s potential for working as a phototransistor. Despite the low mobilities of the devices, a sensitive photodetector was made, showing drain current variation of nearly one order of magnitude under yellow light. CSC technique’s simplicity and versatility was confirmed, as three different semiconductors were successfully implemented into functional devices.

Sharing the surplus: a just and efficient proposal for environments with externalities

Economic activities, both on the macro and micro level, often entail wide-spread externalities. This in turn leads to disputes regarding the compensation levels to the various parties affected. We propose a general, yet simple, method of deciding upon the distribution of the gains (costs) of cooperation in the presence of externalities. This method is shown to be the unique one satisfying several desirable properties. Furthermore, we illustrate the use of this method to resolve the sharing of benefits generated by international climate control agreements.

Chebyshev polynomial approximation to approximate partial differential equations

This paper suggests a simple method based on Chebyshev approximation at Chebyshev nodes to approximate partial differential equations. The methodology simply consists in determining the value function by using a set of nodes and basis functions. We provide two examples. Pricing an European option and determining the best policy for chatting down a machinery. The suggested method is flexible, easy to program and efficient. It is also applicable in other fields, providing efficient solutions to complex systems of partial differential equations.

Polymerase chain reaction amplification of genomic fragments of bovine herpesvirus-1

Especial conditions were developed for the amplification of five DNA segments from US region of BHV-1 by polymerase chain reaction. In order to eliminate most nonspecific products it was found that addition of three cosolvents DMSO, glycerol and NP 40 was a simple method for increasing the specificity of amplification.

Préservation de la fertilité masculine et cancer [Fertility preservation and cancer in the male].

Improvement in cancer treatments resulted in an increased number of men surviving cancer. Quality of life has become an important issue in these patients. Anti cancer treatments might have transient or definitive harmful effects on male fertility. Sperm cryoconservation is currently the only proven method to preserve fertility in patients undergoing oncologic treatment. It should be proposed to every patient at reproductive age before chemotherapy, radiotherapy or any surgery involving reproductive tract. Despite low use rate, this simple method could allow patients presenting infertility after treatment to father a child.

Sensitive headspace gas chromatography analysis of free and conjugated 1-methoxy-2-propanol in urine

Glycol ethers still continue to be a workplace hazard due to their important use on an industrial scale. Currently, chronic occupational exposures to low levels of xenobiotics become increasingly relevant. Thus, sensitive analytical methods for detecting biomarkers of exposure are of interest in the field of occupational exposure assessment. 1-Methoxy-2-propanol (1M2P) is one of the dominant glycol ethers and the unmetabolized urinary fraction has been identified to be a good biological indicator of exposure. An existing analytical method including a solid-phase extraction and derivatization before GC/FID analysis is available but presents some disadvantages. We present here an alternative method for the determination of urinary 1M2P based on the headspace gas chromatography technique. We determined the 1M2P values by the direct headspace method for 47 samples that had previously been assayed by the solid-phase extraction and derivatization gas chromatography procedure. An inter-method comparison based on a Bland-Altman analysis showed that both techniques can be used interchangeably. The alternative method showed a tenfold lower limit of detection (0.1 mg/L) as well as good accuracy and precision which were determined by several urinary 1M2P analyses carried out on a series of urine samples obtained from a human volunteer study. The within- and between-run precisions were generally about 10%, which corresponds to the usual injection variability. We observed that the differences between the results obtained with both methods are not clinically relevant in comparison to the current biological exposure index of urinary 1M2P. Accordingly, the headspace gas chromatography technique turned out to be a more sensitive, accurate, and simple method for the determination of urinary 1M2P.[Authors]

Calculation of Franck-Condon factors including anharmonicity: simulation of the C2 H4+ X̃2B 3u←C2 H4X̃1 Ag band in the photoelectron spectrum of ethylene

Our new simple method for calculating accurate Franck-Condon factors including nondiagonal (i.e., mode-mode) anharmonic coupling is used to simulate the C2H4+X2B 3u←C2H4X̃1 Ag band in the photoelectron spectrum. An improved vibrational basis set truncation algorithm, which permits very efficient computations, is employed. Because the torsional mode is highly anharmonic it is separated from the other modes and treated exactly. All other modes are treated through the second-order perturbation theory. The perturbation-theory corrections are significant and lead to a good agreement with experiment, although the separability assumption for torsion causes the C2 D4 results to be not as good as those for C2 H4. A variational formulation to overcome this circumstance, and deal with large anharmonicities in general, is suggested

How does basis set superposition error change the potential surfaces for hydrogen-bonded dimers?

We describe a simple method to automate the geometric optimization of molecular orbital calculations of supermolecules on potential surfaces that are corrected for basis set superposition error using the counterpoise (CP) method. This method is applied to the H-bonding complexes HF/HCN, HF/H2O, and HCCH/H2O using the 6-31G(d,p) and D95 + + (d,p) basis sets at both the Hartree-Fock and second-order Møller-Plesset levels. We report the interaction energies, geometries, and vibrational frequencies of these complexes on the CP-optimized surfaces; and compare them with similar values calculated using traditional methods, including the (more traditional) single point CP correction. Upon optimization on the CP-corrected surface, the interaction energies become more negative (before vibrational corrections) and the H-bonding stretching vibrations decrease in all cases. The extent of the effects vary from extremely small to quite large depending on the complex and the calculational method. The relative magnitudes of the vibrational corrections cannot be predicted from the H-bond stretching frequencies alone

PEG-b-PPS diblock copolymer aggregates for hydrophobic drug solubilization and release: cyclosporin A as an example

Micelles formed from amphiphilic block copolymers have been explored in recent years as carriers for hydrophobic drugs. In an aqueous environment, the hydrophobic blocks form the core of the micelle, which can host lipophilic drugs, while the hydrophilic blocks form the corona or outer shell and stabilize the interface between the hydrophobic core and the external medium. In the present work, mesophase behavior and drug encapsulation were explored in the AB block copolymeric amphiphile composed of poly(ethylene glycol) (PEG) as a hydrophile and poly(propylene sulfide) PPS as a hydrophobe, using the immunosuppressive drug cyclosporin A (CsA) as an example of a highly hydrophobic drug. Block copolymers with a degree of polymerization of 44 on the PEG and of 10, 20 and 40 on the PPS respectively (abbreviated as PEG44-b-PPS10, PEG44-b-PPS20, PEG44-b-PPS40) were synthesized and characterized. Drug-loaded polymeric micelles were obtained by the cosolvent displacement method as well as the remarkably simple method of dispersing the warm polymer melt, with drug dissolved therein, in warm water. Effective drug solubility up to 2 mg/mL in aqueous media was facilitated by the PEG- b-PPS micelles, with loading levels up to 19% w/w being achieved. Release was burst-free and sustained over periods of 9-12 days. These micelles demonstrate interesting solubilization characteristics, due to the low glass transition temperature, highly hydrophobic nature, and good solvent properties of the PPS block