A quantitative validated method using liquid chromatography and chemometric analysis for evaluation of raw material oF Maytenus ilicifolia (Schrad.) Planch., Celastraceae

The hydroalcoholic extracts prepared from standard leaves of Maytenus ilicifolia and commercial samples of espinheira-santa were evaluated qualitatively (fingerprinting) and quantitatively. In this paper, fingerprinting chromatogram coupled with Principal Component Analysis (PCA) is described for the metabolomic analysis of standard and commercial espinheira-santa samples. The epicatechin standard was used as an external standard for the development and validation of a quantitative method for the analysis in herbal medicines using a photo diode array detector. This method has been applied for quantification of epicatechin in commercialized herbal medicines sold as espinheira-santa in Brazil and in the standard sample of M. ilicifolia.

Stability indicating HPLC method for simultaneous determination of moxifloxacin hydrochloride and ketorolac tromethamine in pharmaceutical formulations

A simple, RP-HPLC method was established for determining moxifloxacin and ketorolac in pharmaceutical formulations. Moxifloxacin, ketorolac and their degradation products were separated using C8 column with methanol and phosphate buffer pH 3.0 (55:45 v/v) as the mobile phase. Detection was performed at 243 nm using a diode array detector. The method was validated using ICH guidelines and was linear in the range 20-140 µg mL-1 for both analytes. Good separation of both the analytes and their degradation products was achieved using this method. The developed method can be applied successfully for the determination of moxifloxacin and ketorolac.

Determinação de bussulfano em plasma através de cromatografia líquida de alta eficiência com detector de arranjo de diodos e derivatização com dietilditiocarbamato de sódio

A high performance liquid chromatographic-diode array detection method for the determination of busulfan in plasma was developed and validated. Sample preparation consisted of protein precipitation followed by derivatization with sodium diethyldithiocarbamate and liquid-liquid extraction with methyl-tert-butyl ether. Chromatograms were monitored at 277 nm. Separation was carried out on a Lichrospher RP 18 column (5 µm, 250 x 4 mm). The mobile phase consisted of water and acetonitrile (20:80, v/v). The method presented adequate specificity, linearity, precision and accuracy and allowed reliable determination of busulfan in clinical plasma samples, being applied to three patients submitted to bone marrow transplantation.

Máscaras mecânicas de sombra por eletrocorrosão para dispositivos eletro-ópticos

Shadow masks are used in manufacturing processes for electro-optic devices to transfer patterns with different shapes and dimensions. For fabrication of organic based devices, shadow masks should be made of materials stable against organic solvents, high temperature, and robust, remaining unchanged after multiple cycles of use and fixation. Thus, stainless steel is suitable for shadow masks. A simple, cheap and quick method of obtaining shadow masks by electrochemical corrosion of stainless steel is reported. The shadow mask was used to evaporate cathode material to obtain an organic light emitting diode with active area of 9 mm². This device exhibited a turn-on voltage of 5 V and luminance of 14 cd/m².

Isolamento do verbacosídeo e validação de método analítico para padronização do extrato bruto das partes aéreas de Buddleja stachyoides Cham. & Schltdl. (Scrophulariaceae)

Phenylpropanoid glycoside verbascoside was isolated and identified from the ethyl acetate fraction of the aerial parts of Buddleja stachyoides Cham. & Schltdl. by 1H-NMR. A method using high-performance liquid chromatography has been developed and validated for determination of verbascoside in alcoholic crude extract of the aerial parts of B. stachyoides. Analysis was performed on a Phenomenex® Gemini-NX C18 analytical column (250 mm × 4.6 mm; 5 µm) using a mobile phase (pump A - aqueous solution containing H2SO4 (0.01 M), H3PO4 (0.4%), and (C2H5)2NH (0.4%); pump B - methanol:aqueous (95:5) solution containing H2SO4 (0.05 M), H3PO4 (2%), and (C2H5)2NH (0.2%); pump C - acetonitrile:aqueous (90:10) solution containing H2SO4 (0.05 M) and H3PO4 (2%)) and a diode array detector at 325 nm. The method was validated in accordance with ANVISA guidelines and may be applied to quality control of herbal medicine with aerial parts of B. stachyoides.

Phenolic composition and antioxidant properties of Brazilian honeys

The antioxidant activities and polyphenolic levels of "assa peixe," "cambara," and "morrão de candeia" Brazilian honeys were investigated. Phenolic extracts of 11 honeys were evaluated spectrophotometrically to determine their total phenolic and flavonoid contents, and their antioxidant activities were measured using DPPH, ABTS, and FRAP assays. High-performance liquid chromatography coupled with diode array detection was applied to determine the phenolic composition of the honey extracts. The presence of fourteen phenolic compounds was established (eleven phenolic acids and three flavonoids), as well as HMF and abscisic acid. Principal component analysis was applied to classify the honey samples according to their floral origins.

DETECTION AND QUANTIFICATION OF PHYTOCHEMICAL MARKERS OF Ilex paraguariensis BY LIQUID CHROMATOGRAPHY

Ilex paraguariensis (yerba-mate) is used as a beverage, and its extract requires adequate quality control methods in order to guarantee quality and safe use. Strategies to develop and optimize a chromatographic method to quantify theobromine, caffeine, and chlorogenic acid in I. paraguariensis extracts were evaluated by applying a quality by design (QbD) model and ultra high-performance liquid chromatography (UHPLC). The presence of these three phytochemical markers in the extracts was evaluated using UHPLC-MS and was confirmed by the chromatographic bands in the total ion current traces (m/z of 181.1 [M+H]+, 195.0 [M+H]+, and 353.0 [M−H]−, respectively). The developed method was then transferred to a high-performance liquid chromatography (HPLC) platform, and the three phytochemical markers were used as external standards in the validation of a method for analyses of these compounds in extracts using a diode array detector (DAD). The validated method was applied to quantify the chlorogenic acid, caffeine, and theobromine in the samples. HPLC-DAD chromatographic fingerprinting was also used in a multivariate approach to process the entire data and to separate the I. paraguariensis extracts into two groups. The developed method is very useful for qualifying and quantifying I. paraguariensis extracts.

COMPARAÇÃO DE MÉTODOS POR CROMATOGRAFIA LÍQUIDA NA DETERMINAÇÃO DE MULTIRRESÍDUOS DE AGROTÓXICOS EM MORANGOS

Liquid chromatography is often used for the determination of pesticide multiresidues in foods. In Brazil, the strawberry crop is an example of a food with high levels of irregularities because of the application of pesticides. This is a major concern from the perspective of food safety, environmental protection, and certification for food export. The purpose of this study is to evaluate and compare chromatographic separation and detection methods in relation to a newly developed and validated method using ultra high performance liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) for the analytical determination of pesticides in strawberries. The comparisons were based on evaluations of the analysis time, consumption of the solvent in the mobile phase, injection volume, detectability, matrix effect, and recovery. The results showed that the LC–MS/MS and UHPLC–MS/MS techniques were both extremely efficient at analyzing pesticide residues with different physico-chemical parameters that were present at low concentrations in a complex matrix. The UHPLC separation method provided better chromatographic performance and productivity, which contributed favorably to routine analytical determinations. Detection by MS/MS had better detectability and selectivity compared with the diode array detector.

ESTUDO FITOQUÍMICO, ATIVIDADE ANTIMICROBIANA E CITOTÓXICA DE ESPÉCIMES DE Leonotis nepetifolia L. R. (Br)

Specimens of Leonotis nepetiflolia were obtained from cultivated and wild environments to verify their influences in chemical composition. Phytochemical analyses were conducted for the ethyl acetate phase obtained by partitioning the crude ethanol extract from the cultivated leaves of L. nepetifolia. In doing so, flavonoid 3',4',5-trimethoxy-6,7-dihidroxyflavone (cirsiliol), a chemotaxonomic marker of the family Lamiaceae, was isolated. The results reveal that all phases and extracts tested exhibited weak to moderate antimicrobial activity against the strains of bacteria tested. The evaluation of in vitrocytotoxic and antitumor activity showed that the ethyl acetate phases obtained from both wild and cultivated leaves exhibit high potential cytotoxic and antitumor (> 78.0% of inhibition) activity. The major component of these phases was identified by high-performance liquid chromatography-diode array detector and nuclear magnetic resonance analyses using both 1D and 2D methods. The results further indicate that the flavonoid cirsiliol is the agent responsible for the activity observed in these phases.

MCR-ALS APLICADO NO MONITORAMENTO QUANTITATIVO DO PROCESSO DE ELETRODEGRADAÇÃO DA ATRAZINA USANDO ESPECTROS UV: RESULTADOS COMPARATIVOS COM HPLC-DAD COMO UM MÉTODO DE REFERÊNCIA

Electrodegradation of atrazine in water was performed using homemade (PA and PB) and purchased (PC) boron-doped diamond anodes. The degradation was monitored off-line by analyzing total organic carbon and high performance liquid chromatography with diode array detector (HPLC-DAD) and at-line by UV spectroscopy. The spectra were recorded every 2 min. The rank deficiency problem was resolved by assembling an augmented column-wise matrix. HPLC was employed to separate the original and byproducts degradation components. Aiming the same goal, multivariate curve resolution - alternating least squares (MCR-ALS) was applied to resolve the UV spectroscopic data. Comparison between HPLC and MCR-ALS separations is presented. By using MCR-ALS the spectra of atrazine and two byproducts were successfully resolved and the resulted concentration profiles properly represented the system studied. The ALS explained variance (R2) for PA, PB and PC was equal to 99.99% for all of them and the lack of fit for PA, PB and PC were 0.39, 0.34 and 0.54 respectively. The correlation (R) between the recovered and pure spectra were calculate for each electrodegradation, validating the MCR-ALS results. The average R was equal to 0.997. The spectral and concentration profiles described with this new approach are in agreement with HPLC-DAD results. The proposed method is an alternative to classical analyses for monitoring of the degradation process, mainly due to the simplicity, fast results and economy.

Tasajännitetason nosto polttokennosovelluksessa

Polttokennojen, erityisesti SOFC-kennojen, tutkimuksessa on viime vuosina saavutettu merkittäviä edistysaskelia ja mahdollisuudet kennojen laajamittaiseen hyödyntämiseen paranevat koko ajan. Polttokennojen yleistyessä tarvitaan tehoelektroniikkaa muokkaamaan kennojen tasajännite verkkoon sopivaksi vaihtojännitteeksi. Verkkovaihtosuuntaaja vaatii korkeamman jännitetason, kuin polttokennosta on saatavissa, joten tasajännitetasoa on ensin nostettava. Tässä diplomityössä esitellään kolme eri hakkuritopologiaa ja perehdytään kokosiltahakkurin optimointiin. Hakkurin pääasialliset häviölähteet olivat toision diodisilta ja transistorit. Diodien vaihtaminen piidiodeista piikarbididiodeihin ei parantanut hyötysuhdetta, koska toision jännite tarkastellussa sovelluksessa oli matala. Muuntajan käämiminen litz-johtimella paransi hyötysuhdetta merkittävästi.

Ledivalaisimet rautatiealueiden valaistuksessa

Leditekniikan kehitys viime vuosina on mahdollistanut niiden käytön yleisvalaistuksessa. Tässä työssä tehdään katsaus leditekniikan nykytilaan ja tulevaisuuteen, sekä osoitetaan, että ledivalaisimien energiankulutuksessa ja huoltokustannuksissa tehdyillä säästöillä voidaan kattaa suuremmat hankintakustannukset ja päästä yhtä suuriin tai pienempiin elinkaarikustannuksiin verrattuna perinteisiin kaasupurkausvalaisimiin. Valaisimien määrät on laskettu Dialux-valaistuslaskentaohjelmalla siten että rautatieasemien avolaitureiden ja katettujen laitureiden valaistusvaatimukset täyttyvät. Tuloksia voi soveltaa muihin vastaaviin tiloihin kuten asematunneleihin tai kevyen liikenteen väylille.

Happidispersion karakterisointi laboratoriosekoittimessa

Työn tarkoituksena oli tarkastella uutta kuvantamistekniikkaa käyttäen happikaasun dispergointia keskisakeuksisen massasuspension joukkoon laboratoriosekoittimessa. Työssä pyrittiin tarkastelemaan muodostuvan dispersion homogeenisuutta neljästä eri kuvauspisteestä sekoittimen kannesta ja kyljestä. Samalla tarkasteltiin myös sekoittimen tehonkulutusta sekä tehonkulutuksen ja aikaansaadun dispersion välistä yhteyttä. Työn yhtenä tarkoituksena oli myös tarkastella uuden kuvantamistekniikan mahdollisuuksia tämäntyyppisissä sovellutuksissa, sillä työ kuuluu PulpVision-projektiin, jossa kehitetään massa- ja paperiteollisuuden uusia konenäkösovellutuksia. Työn kokeellinen osuus koostui sekoituskokeista, joissa tarkasteltiin neljästä kuvauspisteestä kahdella sekoittimen nopeudella mänty- ja koivususpensioihin muodostuvaa kuplakokojakaumaa. Sekoituskokeiden lisäksi tehtiin tehonkulutuskokeita, joissa tarkasteltiin sekoittimen tehonkulutusta sekoittimen täyttöasteen funktiona koivu- ja mäntysuspensioilla sekä vedellä. Työn tuloksien perusteella todettiin, että koivususpensiosta havaittujen kuplien pinta-ala oli noin puolet mäntysuspensiosta havaittujen kuplien pinta-alasta. Sekoittimen roottorin pyörimisnopeuden puolittuessa suspensioon dispergoidun hapen kuplakoko kasvoi huomattavasti. Neljästä kuvausyhteestä tarkasteltuna havaittiin pienimpien kuplien esiintyvän sekoittimen alaosassa. Mäntysuspension tehonkulutuksen havaittiin kasvavan viidenneksellä, kun sekoittimen täyttöaste kasvoi 10 %, kun taas koivususpension tehonkulutuksen kasvu oli tästä vain puolet. Kuvantamislaitteiston todettiin olevan tämänkaltaiseen sovellutukseen riittävä, varsinkin kun valonlähteenä käytetään pulssilaseria.

Ablação de tumor de canal anal tratado com laser de diodo: seguimento após 17 meses

The Nd:YAG laser is used as the palliative treatment of obstructive and/or hemorrhagic intestinal lesions with an effective but temporary symptomatic relief, with symptoms and signs recurrence after six to eight weeks. This report describes the treatment of a patient bearing a low rectal adenocarcinoma through diode laser ablation and the result after 17 months.

Performance and scalability of isolated DC-DC converter topologies in low voltage, high current applications

Fuel cells are a promising alternative for clean and efficient energy production. A fuel cell is probably the most demanding of all distributed generation power sources. It resembles a solar cell in many ways, but sets strict limits to current ripple, common mode voltages and load variations. The typically low output voltage from the fuel cell stack needs to be boosted to a higher voltage level for grid interfacing. Due to the high electrical efficiency of the fuel cell, there is a need for high efficiency power converters, and in the case of low voltage, high current and galvanic isolation, the implementation of such converters is not a trivial task. This thesis presents galvanically isolated DC-DC converter topologies that have favorable characteristics for fuel cell usage and reviews the topologies from the viewpoint of electrical efficiency and cost efficiency. The focus is on evaluating the design issues when considering a single converter module having large current stresses. The dominating loss mechanism in low voltage, high current applications is conduction losses. In the case of MOSFETs, the conduction losses can be efficiently reduced by paralleling, but in the case of diodes, the effectiveness of paralleling depends strongly on the semiconductor material, diode parameters and output configuration. The transformer winding losses can be a major source of losses if the windings are not optimized according to the topology and the operating conditions. Transformer prototyping can be expensive and time consuming, and thus it is preferable to utilize various calculation methods during the design process in order to evaluate the performance of the transformer. This thesis reviews calculation methods for solid wire, litz wire and copper foil winding losses, and in order to evaluate the applicability of the methods, the calculations are compared against measurements and FEM simulations. By selecting a proper calculation method for each winding type, the winding losses can be predicted quite accurately before actually constructing the transformer. The transformer leakage inductance, the amount of which can also be calculated with reasonable accuracy, has a significant impact on the semiconductor switching losses. Therefore, the leakage inductance effects should also be taken into account when considering the overall efficiency of the converter. It is demonstrated in this thesis that although there are some distinctive differences in the loss distributions between the converter topologies, the differences in the overall efficiency can remain within a range of a few percentage points. However, the optimization effort required in order to achieve the high efficiencies is quite different in each topology. In the presence of practical constraints such as manufacturing complexity or cost, the question of topology selection can become crucial.