Versatile microanalytical system with porous polypropylene capillary membrane for calibration gas generation and trace gaseous pollutants sampling applied to the analysis of formaldehyde, formic acid, acetic acid and ammonia in outdoor air

The analytical determination of atmospheric pollutants still presents challenges due to the low-level concentrations (frequently in the mu g m(-3) range) and their variations with sampling site and time In this work a capillary membrane diffusion scrubber (CMDS) was scaled down to match with capillary electrophoresis (CE) a quick separation technique that requires nothing more than some nanoliters of sample and when combined with capacitively coupled contactless conductometric detection (C(4)D) is particularly favorable for ionic species that do not absorb in the UV-vis region like the target analytes formaldehyde formic acid acetic acid and ammonium The CMDS was coaxially assembled inside a PTFE tube and fed with acceptor phase (deionized water for species with a high Henry s constant such as formaldehyde and carboxylic acids or acidic solution for ammonia sampling with equilibrium displacement to the non-volatile ammonium ion) at a low flow rate (8 3 nLs(-1)) while the sample was aspirated through the annular gap of the concentric tubes at 25 mLs(-1) A second unit in all similar to the CMDS was operated as a capillary membrane diffusion emitter (CMDE) generating a gas flow with know concentrations of ammonia for the evaluation of the CMDS The fluids of the system were driven with inexpensive aquarium air pumps and the collected samples were stored in vials cooled by a Peltier element Complete protocols were developed for the analysis in air of NH(3) CH(3)COOH HCOOH and with a derivatization setup CH(2)O by associating the CMDS collection with the determination by CE-C(4)D The ammonia concentrations obtained by electrophoresis were checked against the reference spectrophotometric method based on Berthelot s reaction Sensitivity enhancements of this reference method were achieved by using a modified Berthelot reaction solenoid micro-pumps for liquid propulsion and a long optical path cell based on a liquid core waveguide (LCW) All techniques and methods of this work are in line with the green analytical chemistry trends (C) 2010 Elsevier B V All rights reserved

An Evaluation of Effective Fiber in Beef Feedlot Finishing Diets

A study was designed to collect a database of Iowa feedlot rations for determination of effective neutral detergent fiber (NDF) in complete diets from fiber analysis and particle size determination of individual feed ingredients and compare this with particle size determination of mixed wet rations. Seventy-one beef finishing total mixed rations were collected by ISU Extension Beef Field Specialists across Iowa. Producers were asked to complete a form assessing the acidosis risk associated with each ration. The average NDF of these diets was 25.9%. Of the total mixed rations 1.33 % remained in the top tray (>.75 in.), 47.27 % remained in the middle tray (>.31 in.), and 50.88 % was smaller than the .31 in screen. The effective NDF (eNDF) calculated from the eNDF of the ingredients averaged 10.56%. Estimated eNDF from total diet NDF and the percentage of the total diet in the top and middle trays averaged 12.47%. The calculated eNDF from non-grain sources alone averaged 3.6%. The percentage of digestive deads was weakly related to the percentage of the ration in the bottom tray (r=.19), the percentage in the top tray (r=- .46) and the effective NDF of the ration (r=-.23). The percentage of bloat was related to the total NDF of the diet (r=.28) and the effective fiber from non-grain sources (r=-.23). The number of off-feed incidences was related to the dry matter of the ration (r=.38), the apparent eNDF (r=-.28) and the percentage of ration in the bottom tray (r=.24). This study confirms that there is some relationship between effective NDF of the diet, effective NDF from non-grain sources or diet particle size; and acidosis indicators. These relationships are weak, however, indicating that other factors such as feedbunk management, feed processing, feed presentation and feed mixing likely also play a role in the incidence of acidosis in feedlot cattle.

Efeito da adição de extrato de casca de jabuticaba nas características físico-químicas e sensoriais de queijo petit suisse

A busca pela melhoria da qualidade de vida e a procura por alimentos naturais e funcionais são crescentes. A incorporação de prebióticos e corantes naturais pode agregar valor ao produto, por serem capazes de melhorar sua qualidade e por apresentarem grandes atrativos tecnológicos. Portanto, o objetivo deste trabalho foi avaliar o efeito da adição de prebióticos (inulina e oligofrutose) e corante natural (extrato de casca de jabuticaba) nas características de queijo petit suisse. Foi realizada análise da composição físico-química (extrato seco total, cinzas, proteínas, lipídeos, carboidratos e acidez titulável) logo após o processamento, análise do pH, colorimetria, teor de compostos bioativos e atividade antioxidante em diferentes tempos de armazenamento (0, 7, 14, 21 e 28 dias), análise do teor de fibras alimentares da formulação de queijo petit suisse com maior atividade antioxidante ao final da vida de prateleira e análises microbiológica e sensorial. O queijo petit suisse elaborado foi dividido em cinco formulações, de acordo com a concentração de corante natural incorporado, que foram 0%, 1,5%, 2,0%, 2,5% e 3,0%. Os dados obtidos com as análises realizadas logo após o processamento e análise sensorial foram submetidos à análise de variância e teste de Tukey, os dados obtidos com as análises realizadas em diferentes tempos de armazenamento foram submetidos à análise de variância e estudo do comportamento cinético, e a análise de fibras e microbiológica foi analisada por meio de estatística descritiva. Os valores de extrato seco total, proteínas, lipídeos, cinzas e carboidrato não diferiram significativamente (p>0,05) entre as formulações. A formulação sem adição de corante natural apresentou menor acidez (p≤0,05), e com o aumento da concentração de corante natural, maior foi a acidez do queijo. Os teores de antocianinas, fenólicos totais e capacidade antioxidante foram maiores com o aumento da concentração de corante incorporado, sendo que o teor de antocianinas reduziu com o decorrer do tempo de armazenamento. O valor encontrado de fibras para a formulação contendo 3,0% de corante natural foi baixo, e o produto não apresentou alegação de propriedade funcional. A fim de verificar se o queijo estava próprio para o consumo, foi realizada análise microbiológica para coliformes termotolerantes, estando todas as formulações de queijo petit suisse em condições sanitárias satisfatórias. A análise sensorial foi realizada em duas etapas. Na primeira etapa foi realizado teste de aceitação com avaliação dos atributos cor, sabor, consistência e impressão global, e intenção de compra para todas as formulações com incorporação de corante natural. Na segunda etapa foi realizado o teste de aceitação com informação nutricional do produto para a amostra mais aceita na primeira etapa. Como resultado, foi observado que o atributo cor foi o único que apresentou diferença significativa (p≤0,05) entre as formulações, sendo as mais aceitas com concentração 2,5% e 3,0%. De forma geral, todas as formulações foram bem aceitas, porém, a formulação com maior adição de corante natural foi a que xiii apresentou maiores notas. Assim, o queijo com maior concentração de corante natural foi o utilizado na segunda etapa sensorial, sendo observada influência das informações nos atributos cor e consistência (p≤0,05). Dessa forma, a utilização de prebióticos e corante natural de casca de jabuticaba em queijo petit suisse foi viável por não alterar a composição centesimal do produto, além de conferir ao produto uma coloração atrativa.

Kuituvuoto reikäsihdillä massan syöttövaiheessa

Diplomityön tarkoituksena oli kehittää tutkimuslaite, jolla pystyttäisiin tutkimaan sellumassan syöttötapahtumaa reikäsihdillä ja tarkastelemaan syöttöhetkellä tapahtuvaa kuituhäviötä. Laitteen suunnittelun ja valmistuksen tavoitteena oli myös saada tutkimuslaite mahdollisim-man modifioitavaksi (syöttöaukon koko, muoto ja erityyppiset reikäsihdit ja näiden vaikutukset sellukuitujen hävikkiin). Haluttiin myös mahdollisuus syöttötapahtuman kuvaamiseen esim. suurnopeuskameroin, joka otettiinkin huomioon laiteosia valittaessa (läpinäkyvä akryyli). Tutkimuslaitteen kestävyyttä erilaisissa prosessiolosuhteissa haluttiin korostaa (voidaan operoida laajalla pH ja lämpötila-alueilla, sekä syöttöpainetta voidaan muunnella). Diplomityön kirjallisuusosassa käsitellään kuituvuodon aiheuttamia haittoja, joista tärkein on taloudellinen menetys. Näiden lisäksi kirjallisuusosassa tarkastellaan pääpirteittäin pesume-netelmiä ja käydään läpi kuitusulpun suotautumiseen vaikuttavia tekijöitä. Diplomityöhön sisältyi tutkimuslaitteen suunnittelun ja valmistuksen lisäksi myös laitteen toi-mivuuden testaus. Testit suoritettiin pohjoismaisella koivusellulla. Koivusellu otettiin happi-vaiheen jälkeisen pesurin poistosta. Massalle suoritettiin KAPPA-luvun, SR-luvun, viskositee-tin ja syrjäytys -määritykset, sekä kuituanalyysi. Laitteella suoritettiin 7 %, 10 % ja 12 % sakeuksisten massojen koeajotestit. Suodokset otettiin talteen jatkotutkimuksiin, jossa niistä mitattiin kuituvuoto. 10 % suodokselle suoritettiin myös kuituanalyysi. Tuloksista nähtiin, että 7 % sakeuksinen massa antoi lähes nelinkertaisen kuituvuotomäärän 10 % sakeuksiseen massan syöttöön nähden.

Analytics for the modified kraft pulps

Tämän diplomityön tavoitteena on kehittää sopiva analyyttinen menetelmä muokatun kraft-sellukuidun substituutioasteen (DS) kvantitatiivista määrittämistä varten. Muokkauksella tarkoitetaan tässä yhteydessä joko kovalenttisesti tai adsorption avulla tapahtuvaa molekyylin kiinnittymistä sellukuidun pinnalle. Työn kirjallisuusosuudessa käsitellään lyhyesti eri muokkaustapoja ja yhdisteitä joiden avulla voidaan saavuttaa haluttuja ominaisuuksia sellusta valmistetuille lopputuotteille. Lisäksi kirjallisuusosuudessa käydään läpi käyttötarkoitukseen soveltuvimpia suoria ja epäsuoria analyysimenetelmiä. Analyysimenetelmistä kaikkein lupaavimpia testattiin työn kokeellisessa osassa. Diplomityön kokeellisessa osassa keskityttiin kehittämään muokatulle sellulle kvantitatiivista menetelmää DS:n määrittämiseksi Fourier-muunnos infrapuna-vaimennettu kokonaisheijastus (FTIR-ATR) spektrometrillä. Kirjallisuuskatsauksessa ei löytynyt yhtään dokumentoitua tutkimusta, jossa FTIR-ATR menetelmää olisi käytetty muokatun sellukuidun kvantitatiiviseen tutkimukseen. Muiden analyysimenetelmien, kuten alkuaineanalyysin, termogravimetrisen analyysin (TGA) ja valomikroskopian avulla pyrittiin tuottamaan lisätietoa muokkauksesta. Kvantitatiivisen FTIR-ATR menetelmän kehitykseen käytetyt muokatut sellukuidut olivat selluloosa-asetaattia ja selluloosa betainaattia. Saatujen tulosten perusteella muokattujen sulfiitti- ja kraft sellukuitujen DS:n kvantitatiivinen määrittäminen on mahdollista FTIR-ATR menetelmällä. Vähäinen kalibrointipisteiden määrä vaikeutti tarkan analyysimenetelmän tekemistä. Kehitetyn menetelmän suurimpina ongelmina olivat kiinteiden näytteiden heterogeenisyys sekä mahdollisten epäpuhtauksien tunnistaminen. Jatkotutkimusten avulla kehitettyä menetelmää on kuitenkin mahdollista käyttää muokattujen sellukuitujen jatkuvaan analysointiin selluteollisuudessa.

Effects of aging and maternal protein restriction on the muscle fibers morphology and neuromuscular junctions of rats after nutritional recovery

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Development of new analytical procedures aimet at the characterization of artistic samples

In this thesis, new advances in the development of spectroscopic based methods for the characterization of heritage materials have been achieved. As concern FTIR spectroscopy new approaches aimed at exploiting near and far IR region for the characterization of inorganic or organic materials have been tested. Paint cross-section have been analysed by FTIR spectroscopy in the NIR range and an “ad hoc” chemometric approach has been developed for the elaboration of hyperspectral maps. Moreover, a new method for the characterization of calcite based on the use of grinding curves has been set up both in MIR and in FAR region. Indeed, calcite is a material widely applied in cultural heritage, and this spectroscopic approach is an efficient and rapid tool to distinguish between different calcite samples. Different enhanced vibrational techniques for the characterisation of dyed fibres have been tested. First a SEIRA (Surface Enhanced Infra-Red Absorption) protocol has been optimised allowing the analysis of colorant micro-extracts thanks to the enhancement produced by the addition of gold nanoparticles. These preliminary studies permitted to identify a new enhanced FTIR method, named ATR/RAIRS, which allowed to reach lower detection limits. Regarding Raman microscopy, the research followed two lines, which have in common the aim of avoiding the use of colloidal solutions. AgI based supports obtained after deposition on a gold-coated glass slides have been developed and tested spotting colorant solutions. A SERS spectrum can be obtained thanks to the photoreduction, which the laser may induce on the silver salt. Moreover, these supports can be used for the TLC separation of a mixture of colorants and the analyses by means of both Raman/SERS and ATR-RAIRS can be successfully reached. Finally, a photoreduction method for the “on fiber” analysis of colorant without the need of any extraction have been optimised.

Morphological analysis of glass, carbon and glass/carbon fiber posts and bonding to self or dual-cured resin luting agents

OBJECTIVE: The aim of this study was to evaluate the morphology of glass (GF), carbon (CF) and glass/carbon (G/CF) fiber posts and their bond strength to self or dual-cured resin luting agents. MATERIAL AND METHODS: Morphological analysis of each post type was conducted under scanning electron microscopy (SEM). Bond strength was evaluated by microtensile test after bisecting the posts and re-bonding the two halves with the luting agents. Data were subjected to two-way ANOVA and Tukey's test (α=0.05). Failure modes were evaluated under optical microscopy and SEM. RESULTS: GF presented wider fibers and higher amount of matrix than CF, and G/CF presented carbon fibers surrounded by glass fibers, and both involved by matrix. For CF and GF, the dual-cured material presented significantly higher (p<0.05) bond strength than the self-cured agent. For the dual agent, CF presented similar bond strength to GF (p>0.05), but higher than that of G/CF (p<0.05). For the self-cured agent, no significant differences (p>0.05) were detected, irrespective of the post type. For GF and G/CF, all failures were considered mixed, while a predominance of adhesive failures was detected for CF. CONCLUSION: The bonding between fiber posts and luting agents was affected by the type of fibers and polymerization mode of the cement. When no surface treatment of the post is performed, the bonding between glass fiber post and dual-cured agent seems to be more reliable.

A simple method for non-linear analysis of steel fiber reinforced concrete

This paper proposes a physical non-linear formulation to deal with steel fiber reinforced concrete by the finite element method. The proposed formulation allows the consideration of short or long fibers placed arbitrarily inside a continuum domain (matrix). The most important feature of the formulation is that no additional degree of freedom is introduced in the pre-existent finite element numerical system to consider any distribution or quantity of fiber inclusions. In other words, the size of the system of equations used to solve a non-reinforced medium is the same as the one used to solve the reinforced counterpart. Another important characteristic of the formulation is the reduced work required by the user to introduce reinforcements, avoiding ""rebar"" elements, node by node geometrical definitions or even complex mesh generation. Bounded connection between long fibers and continuum is considered, for short fibers a simplified approach is proposed to consider splitting. Non-associative plasticity is adopted for the continuum and one dimensional plasticity is adopted to model fibers. Examples are presented in order to show the capabilities of the formulation.

Failure analysis of belt/roll tribological pair used for the production of eucalypt fiber panels

The premature failure of a large agglomeration machine used for the annual production of 360,000 m(3) of eucalypt fiber panels was investigated to identify the nucleation and growth mechanisms of cracking in PH stainless steel belts (126 m x 2.9 m x 3.0 mm). These belts are used to compress a cushion composed of eucalyptus fibers and glue, being the pressure transmitted from the pistons by the action of numerous case-hardening steel rolls. Examination of the belt working interfaces (belt/rolls and belt/eucalypt fibers) indicated that the main cracking was nucleated on the belt/roll interface and that there is a clear relationship between the crack nucleation and the presence of superficial irregularities, which were observed on the belt/roll working surface. Used rolls showed the presence of perimetric wear marks and 2 mu m silicon-rich encrusted particles (identified as silicon carbide). Lubricant residues contained the presence of helicoidal wires, which were originated by the release of the stainless steel cleaning brush bristles, and 15 mu m diameter metallic particles, which were generated by material detachment of the belt. The presence of foreign particles on the tribological interface contributed to an increase of the shear stresses at the surfaces and, consequently, the number of the contact fatigue crack nucleation sites in the belt/roll tribo-interface. The cracking was originated on the belt/roll interface of the stainless steel belt by a mixed rolling/slip contact fatigue mechanism, which promoted spalling and further nucleation and growth of conventional fatigue cracks. Finally, the system lubrication efficiency and the cleaning procedure should be optimised in order to increase the life expectancy of the belt. (c) 2006 Elsevier Ltd. All rights reserved.

Analysis of genomic and functional RFLP derived markers associated with sucrose content, fiber and yield QTLs in a sugarcane (Saccharum spp.) commercial cross

Expressed sequence tags derived markers have a great potential to be used in functional map construction and QTL tagging. In the present work, sugarcane genomic probes and expressed sequence tags having homology to genes, mostly involved in carbohydrate metabolism were used in RFLP assays to identify putative QTLs as well as their epistatic interactions for fiber content, cane yield, pol and tones of sugar per hectare, at two crop cycles in a progeny derived from a bi-parental cross of sugarcane elite materials. A hundred and twenty marker trait associations were found, of which 26 at both crop cycle and 32 only at first ratoon cane. A sucrose synthase derived marker was associated with a putative QTL having a high negative effect on cane yield and also with a QTL having a positive effect on Pol at both crop cycles. Fifty digenic epistatic marker interactions were identified for the four traits evaluated. Of these, only two were observed at both crop cycles.

Hollow fiber-based liquid-phase microextraction (HF-LPME) of isradipine and its main metabolite followed by chiral HPLC analysis: application to an in vitro biotransformation study

An enantioselective liquid chromatographic method using two-phase hollow fiber liquid-phase microextraction (HF-LPME-HPLC) was developed for the determination of isradipine (ISR) enantiomers and its main metabolite (pyridine derivative of isradipine, PDI) in microsomal fractions isolated from rat liver. The analytes were extracted from 1 mL of microsomal medium using a two-phase HF-LPME procedure with hexyl acetate as the acceptor phase, 30 min of extraction, and sample agitation at 1,500 rpm. For the first time, ISR enantiomers and PDI were resolved. For this separation, a ChiralpakA (R) AD column with hexane/2-propanol/ethanol (94:04:02, v/v/v) as the mobile phase at a flow rate of 1.5 mL min(-1) was used. The column was kept at 23 A +/- 2 A degrees C. The drug and metabolite detection was performed at 325 nm and the internal standard oxybutynin was detected at 225 nm. The recoveries were 23% for PDI and 19% for each ISR enantiomer. The method presented quantification limits (LOQ) of 50 ng mL(-1) and was linear over the concentration range of 50-5,000 and 50-2,500 ng mL(-1) for PDI and each ISR enantiomer, respectively. The validated method was employed to an in vitro biotransformation study of ISR using rat liver microsomal fraction showing that (+)-(S)-ISR is preferentially biotransformed.

Automated static image analysis as a novel tool in describing the physical properties of dietary fiber

Abstract The growing interest in the usage of dietary fiber in food has caused the need to provide precise tools for describing its physical properties. This research examined two dietary fibers from oats and beets, respectively, in variable particle sizes. The application of automated static image analysis for describing the hydration properties and particle size distribution of dietary fiber was analyzed. Conventional tests for water holding capacity (WHC) were conducted. The particles were measured at two points: dry and after water soaking. The most significant water holding capacity (7.00 g water/g solid) was achieved by the smaller sized oat fiber. Conversely, the water holding capacity was highest (4.20 g water/g solid) in larger sized beet fiber. There was evidence for water absorption increasing with a decrease in particle size in regards to the same fiber source. Very strong correlations were drawn between particle shape parameters, such as fiber length, straightness, width and hydration properties measured conventionally. The regression analysis provided the opportunity to estimate whether the automated static image analysis method could be an efficient tool in describing the hydration properties of dietary fiber. The application of the method was validated using mathematical model which was verified in comparison to conventional WHC measurement results.

Radiometric analysis of the light coupled by optimally cut plastic optical fiber amplitude modulating reflectance displacement sensors

A radiometric analysis of the light coupled by optical fiber amplitude modulating extrinsic-type reflectance displacement sensors is presented. Uncut fiber sensors show the largest range but a smaller responsivity. Single cut fiber sensors exhibit an improvement in responsivity at the expense of range. A further increase in responsivity as well as a reduction in the operational range is obtained when the double cut sensor configuration is implemented. The double cut configuration is particularly suitable in applications where feedback action is applied to the moving reflector surface. © 2000 American Institute of Physics.