Effects of water restriction and dirt on grooming behavior in neotropical rodents (Trinomys setosus and T. yonenagae) (Echimyidae).

Grooming in rodents presents an evolutionarily conserved behavioral pattern that may cause water loss since saliva is deposited during washing onto large body surfaces. Trinomys yonenagae and Trinomys setosus are sister species of spiny rats occurring in Brazil, the former inhabiting a paleodesert of fixed dunes in the Caatinga, the latter being found in mesic environments of the Atlantic Forest. Consequently, it is expected that both species evolved under different selective pressures related to water balance, with T. yonenagae presenting mechanisms for dealing with water deprivation not found in T. setosus. Reduction of self-cleaning expression seems to offer a possible way to save water, as previously suggested by studies of the sand-dwelling spiny rat. Therefore, we propose to investigate grooming under four conditions: 'control' (C), a regimen of 'water restriction' (WR), of 'dirt' (D), and the combination of both conflicting stimuli (WR + D), in T. setosus, T. yonenagae, and Rattus norvegicus to compare the behavioral responses of these species. The main differences are observed in the forest dweller: T. setosus expresses a low relative duration of face washing under C, whose value is intermediate between the ones found in the two other species. WR treatment does not alter this pattern, however, the addition of dirt (D, WR + D) significantly increases the relative duration of washing in relation to C. Locomotor activity is decreased both in T. setosus and Wistar rats when they are under WR, a situation that could jeopardize antipredatory performance. T. yonenagae, the sand dweller, maintains a significantly lower expression of washing under C, as previously suggested, and under WR, D and WR + D. In addition, differently from the other two species the sand dweller maintains a normal activity level during all treatments. This study suggests differences in grooming as a strategy alluding to water balance by the two spiny rats inhabiting different ecosystems. A significantly clear pattern that saves water is observed in T. yonenagae, which probably has contributed to his evolution in one of the hottest semiarid areas of the world.

The Role of Amylogenic Fiber Aggregation on the Elasticity of a Lipid Membrane.

This work presents a systematic study of the swelling behavior of a lecithin lamellar phase incorporating different amounts of the short peptide sequence diphenylalanine (FF). Small- and wide-angle X-ray scattering assays provide relevant information about the structure and elasticity of the lamellar stacking. These data show that important changes occur at the interface of the lipid membrane dependent not only on the peptide content but also on the hydration of the lamellar structure. Multilamellar-to-unilamellar transitions, previously observed for an increasing number of peptides, are now observed to be dependent on the hydration of the lamellar phase. Wide-angle X-ray scattering and electron microscopy observations (TEM) provide experimental evidence of peptide aggregation into long amylogenic fibers. We argue that aggregates that partition in water may become large enough to destabilize the lamellar structure. It is also shown that, for a given peptide concentration, the lamellar structure can be rendered more flexible or more rigid, by tuning the hydration.

Multilamellar-to-Unilamellar Transition Induced by Diphenylalanine in Lipid Vesicles.

In the present work, we investigate the effect of two short phenylalanine-based peptides on lipid membranes. A simplified model membrane composed of lecithin vesicles was used to incorporate different amounts of the two amino acid sequences, the dimmer l,l-diphenylallanine (FF) and the trimmer cysteine-diphenylallanine (CFF). Spectroscopic and scattering techniques were applied to probe in detail the structural behavior of lipid membranes in the presence of the peptides. The experimental results demonstrate that both peptides are located mainly at the interface of the membrane interacting with phosphate groups modifying membrane thickness and flexibility. The multilamellar structure of the vesicles is preserved with inclusion of small amounts of FF, accompanied by changes in membrane thickness and elasticity. Finally, a multi- to unilamellar transition is observed as a result of peptide self-association into a crystalline structure onto the membrane interface.

Effect of neodymium:yttrium-aluminum-garnet laser and fluoride on the acid demineralization of enamel.

AIM: The aim of the present study was to evaluate the protective effect of the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser and acidic phosphate fluoride (APF) on enamel erosion caused by hydrochloric acid. METHODS: Fifty human enamel specimens were distributed according to the following treatments (n = 10): untreated (control), APF (1.23%) 4 min, Nd:YAG laser (100 mJ, 1 W, 10 Hz, 141.5 J/cm2 ), APF + Nd:YAG laser, and Nd:YAG laser + APF. For 14 days the specimens were submitted to erosive challenge: 5 min in 3 mL hydrochloric acid (0.01 M, pH 2.2), rinsed with distilled water, and stored in artificial saliva for 3 h. This cycle was repeated four times per day. The calcium (Ca) loss was determined in demineralizing solution by atomic emission spectroscopy, and superficial roughness (Ra) was measured before and after the erosive challenge. RESULTS: The mean Ca loss was (mg/L, ± standard deviation): control 12.74 ± 3.33, APF 1.71 ± 0.11, laser 1.64 ± 0.08, APF + laser 1.38 ± 0.08, and laser + APF 1.48 ± 0.07. Kruskal-Wallis test showed a significant difference between the control and other groups. APF + laser showed minor loss of Ca. After the erosive challenge, the APF + laser group showed Ra alteration. CONCLUSION: A significant reduction in tooth dissolution was observed after fluoride application combined with Nd:YAG irradiation.

Quo vadis? Career of Brazilian ethologists earning a doctoral degree in 2010 / Quo vadis? A carreira dos Etólogos no Brasil que obtiveram seu título de Doutor em 2010

Fifty two doctors (22 male, 30 female) got a degree in Ethology in 2010, according to a previous study; 46 curricula vitae (21 male, 25 female), 88% of the initial group, provided career information at Plataforma Lattes database during a life-span of six years. Employability was high, at least 90% for both sexes. 48% of doctors work at the public sector, holding stable jobs; 40% are professors at public universities. Fellowships provide 10 positions (19%), and the private sector nine jobs (17%); mostly at private universities (15%). Men occupy the majority of positions at public universities (14 of 21, representing 67%), while most women are holding positions at the private sector or as public servants outside professorship (nine out of 13, corresponding to 69%). 70% of fellowship holders are women. 96% advised or are advising academic works. 89% of all are co-authors of at least one peer-reviewed article: a total of 366 reports (male= 166, female= 170; 61 articles.year-1; 1.5 article.year-1.doctor-1). 56% of doctors graduate at Institutions located in the Southeast region, where most graduation programs are. A clear regional transference of doctors is observed when employment is considered, in this case the participation of the Southeast region shrinks to 30%. This indicates a role played by the Southeast region as disseminator of animal behavior knowledge within Brazil. This opens the possibility of an equitable relationship among regions in Brazil concerning higher education in Ethology. It is foreseen a positive effect upon the knowledge of the particular fauna of Brazilian regions, diverse and numerous, and mostly unknown from the ethological point of view. In our sample women are in slightly greater number than men, and are involved in mentoring and publishing, as well as men. Most females holding doctorate in Ethology work in less stable jobs (at private institutions or holding temporary fellowships) and probably endure less favorable conditions regarding research and remuneration. Not surprisingly this is the scenario seen in 30 out of 35 countries of the Organisation for Economic Co-operation and Development community, including in countries like USA and Germany. So it is not enough just to support accessibility; special attention should be given to assure fair working conditions for all. Our data also show a favorable scenario for Ethology in Brazil, mostly associated with the public educational system that is tuition-free and dependent of governmental resources. Recent governmental cutbacks for Science and Technology may curb further expansion of Ethology in Brazil

Cinquenta e dois doutores(as) (22 masculino, 30 feminino) defenderam teses em Etologia em 2010, de acordo com um estudo prévio; 46 curricula vitae (21 masculino, 25 feminino), 88% do grupo inicial, forneceram informações a partir de consulta à base de dados da Plataforma Lattes, durante seis anos. A empregabilidade foi alta, de pelo menos 90% para ambos os sexos. 48% dos doutores(as) trabalham no setor público, e têm empregos estáveis; 40% são professores(as) em universidades públicas. Dez posições são ocupadas por bolsistas (19%), e o setor privado é responsável por nove empregos (17%); a maioria deles em universidades privadas (15%). Homens ocupam a maioria das posições nas universidades públicas (14 de 21, representando 67%), enquanto que a maioria das mulheres tem posição no setor privado ou são servidoras públicas não docentes (nove de 13, correspondendo a 69%). Setenta por cento dos pesquisadores bolsistas são mulheres. 96% supervisionaram ou estão supervisando trabalhos acadêmicos. A maioria (89%) é coautor(a) de pelo menos um artigo peer-reviwed: um total de 366 publicações (masculino= 166, feminino= 170; 61 artigos.ano-1; 1,5 artigos.ano-1.autor-1). 56% dos doutores fizeram Pós Graduação em Instituições do sudeste brasileiro, onde a maioria dos programas de Pós Graduação está situada. Observa-se uma clara transferência regional de doutores quando se considera os empregos ocupados, nesse caso a participação do sudeste se reduz a 30%. Este dado indica que o sudeste pode ser considerado um disseminador de conhecimentos sobre comportamento animal dentro do Brasil. É possível se antever um futuro de relações de maior igualdade entre as regiões brasileiras em relação ao ensino superior de Etologia. Efeitos positivos são previstos com relação ao conhecimento de faunas muito particulares das regiões brasileiras, que são diversas e numerosas, além de majoritariamente pouco conhecidas do ponto de vista etológico. Na presente amostra as mulheres estão ligeiramente mais representadas em número do que os homens, e estão envolvidas em atividades de orientação e publicação, tanto quanto os homens. Entretanto, a maioria das doutoras trabalha em empregos menos estáveis (em instituições privadas ou como bolsistas temporárias), e provavelmente convivem com condições menos favoráveis tanto com relação à pesquisa e à remuneração. Não surpreendentemente este é o cenário visto em 30 dos 35 países da Organisation for Economic Co-operation and Development, inclusive em países como os Estados Unidos e a Alemanha. Não é suficiente, portanto, aumentar a acessibilidade; atenção especial deve ser dispensada de maneira a assegurar condições adequadas de trabalho para todos(as). Os dados também mostram um cenário favorável para a Etologia no Brasil, principalmente no sistema público de educação, que é isento de taxas e dependente de fundos governamentais. Cortes recentes no orçamento governamental da Ciência e Tecnologia podem interferir com a continuidade da expansão da Etologia no Brasil

Steric-induced effects on stabilizing a lamellar structure.

We investigate the behavior of multilamellar phases composed of lecithin and a commercial cosurfactant (Simusol), which is a mixture of ethoxylated fatty acids. Using X-ray scattering and a new procedure to fit the data, relevant parameters characterizing the lamellar structure were determined as a function of membrane composition, varying from 100% of lecithin to 100% of Simulsol. Scattering data illustrating the swelling of the lamellae for different amounts of cosurfactant are presented with the respective behavior of the Caillé parameter. With this experimental approach, we show that the incorporation of ethoxy brushes onto the lipid surface enhances repulsive interactions arising from membrane fluctuations and changes the interactions at the interface between bilayers.

Morphological and mineral analysis of dental enamel after erosive challenge in gastric juice and orange juice.

This study evaluated and compared in vitro the morphology and mineral composition of dental enamel after erosive challenge in gastric juice and orange juice. Human enamel specimens were submitted to erosive challenge using gastric juice (from endoscopy exam) (n = 10), and orange juice (commercially-available) (n = 10), as follows: 5 min in 3 mL of demineralization solution, rinse with distilled water, and store in artificial saliva for 3 h. This cycle was repeated four times a day for 14 days. Calcium (Ca) loss after acid exposure was determined by atomic emission spectroscopy. The presence of carbonate (CO) and phosphate (PO) in the specimens was evaluated before and after the erosive challenge by FT-Raman spectroscopy. Data were tested using t-tests (P < 0.05). Morphology of enamel was observed in scanning electron microscopy (SEM). The mean loss of Ca was: 12.74 ± 3.33 mg/L Ca (gastric juice) and 7.07 ± 1.44 mg/L Ca (orange juice). The analysis by atomic emission spectroscopy showed statistically significant difference between erosive potential of juices (P = 0.0003). FT-Raman spectroscopy found no statistically significant difference in the ratio CO/PO after the erosive challenge. The CO/PO ratios values before and after the challenge were: 0.16/0.17 (gastric juice) (P = 0.37) and 0.18/0.14 (orange juice) (P = 0.16). Qualitative analysis by SEM showed intense alterations of enamel surface. The gastric juice caused more changes in morphology and mineral composition of dental enamel than orange juice. The atomic emission spectroscopy showed to be more suitable to analyze small mineral loss after erosive challenge than FT-Raman.

Development of a heavy metal sorption system through the P=S functionalization of coconut (Cocos nucifera) fibers.

Lignocellulosic residues are interesting materials for the production of heavy metal adsorbents for aquatic systems. Whole fibers taken from coconut (Cocos nucifera) husks were functionalized with the thiophosphoryl (P=S) group by means of the direct reaction with Cl(3)PS, (CH(3)O)(2)ClP=S or (CH(3)CH(2)O)(2)ClP=S in order to obtain an adsorptive system for 'soft' metal ions, particularly Cd(2+). These functionalized fibers (FFs) were characterized by means of elemental analysis, infrared spectroscopy, thermal analysis and acid-base titration. Adsorption isotherms for Cd(2+) fitted the Langmuir model, with binding capacities of 0.2-5 m mol g(-1) of FF at 25 degrees C.

Ionic and histological studies of salivary glands in rats with diabetes and their glycemic state after laser irradiation.

OBJECTIVES: To evaluate the effect of laser irradiation (LI) on the glycemic state and the histological and ionic parameters of the parotid and submandibular glands in rats with diabetes. METHODS: One hundred twenty female rats were divided into eight groups. Diabetes was induced by administration of streptozotocin and confirmed later according to results of glycemia testing. Twenty-nine days after the induction, the parotid and submandibular glands of the rats were irradiated with 5, 10, and 20 J/cm2 using a laser diode (660 nm/100 mW) (without diabetes: C5, C10, and C20; with diabetes: D5, D10, and D20, respectively). On the following day, the rats were euthanized, and blood glucose determined. Histological and ionic analyses were performed. RESULTS: Rats with diabetes without irradiation (D0) showed lipid droplets accumulation in the parotid gland, but accumulation decreased after 5, 10, and 20 J/cm2 of laser irradiation. A decrease in fasting glycemia level from 358.97+/-56.70 to 278.33+/-87.98 mg/dL for D5 and from 409.50+/-124.41 to 231.80+/-120.18 mg/dL for D20 (p<0.05) was also observed. CONCLUSION: LI should be explored as an auxiliary therapy for control of complications of diabetes because it can alter the carbohydrate and lipid metabolism of rats with diabetes.

Dye-enhanced laser fluorescence detection of caries lesions around brackets.

The aim was to evaluate the performance of DIAGNOdent [laser fluorescence(LF) and LFpen] devices enhanced by fluorescent dye in detecting mineral loss around brackets and comparing the inhibitory effect of bonding material on artificial demineralization, and to verify whether LF methods show the same trends of mineral loss. Brackets were bonded to premolar halves with Fuji Ortho LC, Transbond XT, and Ortho Glass LC cements (n = 15). The teeth were soaked in demineralizing solution (pH = 4.8) for 16 days. Mineral loss was calculated by atomic emission spectrometry, and lesions were measured with LF devices with dye [tetrakis N-methylpyridyl porphyrin (TMPyP)]. Groups were compared with regard to LF readings and mineral loss, and performance of caries detection was calculated. Higher mineral loss and LF-TMPyP values occurred in the resin group. LFpen-TMPyP readings were significantly higher in the demineralized groups. Correlation was observed between mineral loss and LF measurements. LF methods are capable of identifying lower demineralization around brackets bonded with resin-modified glass ionomer cements.

Salivary parameters in infants aged 12 to 60 months with Down syndrome.

The purpose of this study was to measure certain components in whole saliva from children with Down syndrome aged 12 months to 60 months. Twenty children with Down syndrome were compared with 18 children without Down syndrome. Whole saliva was collected under slight suction and the salivary pH was measured with a portable pH meter soon after collection. Electrolyte concentrations were determined by inductively coupled argon plasma with atomic emission spectrometry. Sialic acid was determined by thiobarbituric acid assay. Amylase was assayed measuring the maltose produced by the breakdown of starch and peroxidase with ortho-dianisidine. No statistically significant differences were observed in sialic acid, calcium, phosphorus and magnesium concentrations between the group with Down syndrome and the control group. Protein and sodium concentration were higher in the group with Down syndrome compared to the control group. On the other hand, the flow rate, pH, amylase and peroxidase activities and potassium concentration were lower in those with Down syndrome compared to those children in the control group.

Comparison of electrolyte concentrations in whole saliva of individuals with and without cerebral palsy.

OBJECTIVE: To analyze sodium, potassium, calcium, phosphorus, and magnesium concentrations in whole saliva of adolescents with cerebral palsy (CP) and compare them with those of normal individuals. METHOD AND MATERIALS: Thirty-six adolescents with CP aged 12.0 +/- 1.8 years were compared with 36 healthy age-matched individuals. Saliva was collected under slight suction. Electrolyte concentrations were determined by inductively coupled argon plasma with atomic emission spectrometry. RESULTS: Significant differences were observed with matched and unmatched flow rates. Sodium concentrations were significantly decreased, whereas potassium levels were significantly increased in the CP group. No statistically significant differences were observed regarding phosphorus, magnesium, and calcium concentrations between adolescents with CP and controls. CONCLUSION: Our results suggest that there is an alteration in the sodium and potassium concentration in whole saliva of individuals with CP.

Ability of laser fluorescence device associated with fluorescent dyes in detecting and quantifying early smooth surface caries lesions.

A laser fluorescence (LF) device is a portable tool, but it does not measure minor mineral changes. Our in vitro study aim is to propose the association of an LF with two fluorescent dyes and to evaluate the performance in detecting and quantifying early demineralization. Artificial caries lesions are created in 40 primary canine teeth using a demineralizing solution (pH=4.8) for 12, 24, 48, and 96 h. LF measurements are performed with DIAGNOdent after demineralization in these samples and in 20 sound primary teeth. Measurements with LF with 0.2-mM tetrakis(N-methylpyridyl)porphyrin (LF TMPyP) and with 4-mM protoporphyrin IX (LF PPIX) are made. The amount of calcium loss is determined by atomic emission spectrometry. A correlation between LF and LF with dyes and mineral loss and receiver operating characteristics analysis are performed, as well as comparisons of sensitivity, specificity, and accuracy values. Significant correlation is obtained with LF TMPyP and mineral loss of lesions demineralized for 24, 48, and 96 h. Better performance is achieved with LF TMPyP for all parameters than with LF alone. LF PPIX does not present good results. In conclusion, LF TMPyP provides good performance in detecting and quantifying very early enamel caries lesions.

Effect of Er:YAG laser on enamel acid resistance: morphological and atomic spectrometry analysis.

BACKGROUND AND OBJECTIVES: This study evaluated the effect of Er:YAG laser on enamel acid resistance. STUDY DESIGN/MATERIALS AND METHODS: Seventy human enamel slabs were randomly divided into seven groups (n = 10): G1, Er:YAG laser (Key Laser 2, KaVo, Germany) 60 mJ, 2 Hz, 33.3 J/cm2 (handpiece no. 2051, non-contact); G2, Er:YAG laser 80 mJ, 2 Hz, 44.4 J/cm2 (handpiece no. 2051, non-contact); G3, Er:YAG laser 120 mJ, 2 Hz, 66.6 J/cm2 (handpiece no. 2051, non-contact); G4, Er:YAG laser 64 mJ, 2 Hz, 20 J/cm2 (handpiece no. 2055, contact); G5, Er:YAG laser 86.4 mJ, 2 Hz, 26.9 J/cm2 (handpiece no. 2055, contact); G6, Er:YAG laser 135 mJ, 2 Hz, 42.2 J/cm2 (handpiece no. 2055, contact); G7, control. After laser irradiation, samples were submitted to an acid challenge. For both the nos. 2051 and 2055 handpieces, irradiation was performed with a water cooled spray (5.0 ml/minutes). The calcium and phosphorous ions delivered from the tooth surface were quantified by atomic emission spectrometry, and morphological analysis of the enamel surface was performed under scanning electron microscopy. Kruskal-Wallis and multiple comparisons tests were applied to distinguish significant differences among the treatments (alpha = 5%). RESULTS: Groups G1, G2, and G4 presented decreased demineralization. The SEM evaluation revealed different surface alterations as a result of the different energies used. CONCLUSION: Lower energies can decrease enamel solubility without severe alterations of the enamel.

Interpretation of seasonal variation of metals and abiotic properties in a tropical lake using multivariate analysis and MINTEQA2 program.

The hydrological cycle of Lake Ipê and the principal parameters that could affect its abiotic parameters and its metal (Fe, Mn, and Cd) concentrations were investigated. A detailed study of seasonal variations using Principal Components Analysis (PCA) for the most relevant metals (Fe, Mn and Cd) was performed, assisted by the MINTEQA2 geochemical equilibrium program using 15 water abiotic parameters. The abiotic variables and metals in the lake were governed by the hydrological regimen of the Parana River and by the occurrence of occasional flood pulses and rainfall. The occurrence of cadmium is a concern; its presence could be due to industrial or agricultural activities or even to a natural geochemical process.

Electrolyte concentrations in saliva of children aged 6-10 years with Down syndrome.

STUDY DESIGN: In this study sodium, potassium, calcium, phosphorus, zinc, and magnesium ion concentration was analyzed in stimulated whole saliva in 22 children with Down syndrome aged 6 to 10 years. These children were compared with 21 healthy children of the same age. Stimulated saliva was collected by chewing a piece of parafilm for 10 minutes. The pH was measured with a portable pH meter after collection. Electrolyte concentrations were determined by inductively coupled argon plasma with atomic emission spectrometry. RESULTS: No statistically significant differences were observed in phosphorus, zinc, magnesium, and calcium concentration between the children with Down syndrome and the control children. The sodium concentration showed about 66.8% higher value in the Down syndrome than in the control group. On the other hand the flow rate and potassium concentration were lower in the Down syndrome than in the control group. CONCLUSION: Our results suggest that there is alteration in the metabolism of the duct and/or acinar cells of salivary glands of Down syndrome children.

Evaluation of the salt accumulation process during inundation in water resource of Contas river basin (Bahia-Brazil) applying principal component analysis.

The high salinization in some reservoirs of the Contas river basin (Bahia-Brazil) has been erroneously attributed only to concentration by evaporation. However, recent studies of this basin have shown that in period of intense rainfalls, occur an increase of the saline concentration in the flowing rivers of the reservoirs. The application of statistical methods (cluster and principal components analysis) have shown that this fact can be attributed to the discharge of saline waters from the small reservoirs of every drained area, provoked by inundation, is also an important factor in the salinization process. Thus the study of the geochemical variables: Na(+), K(+), Ca(2+), Mg(2+), Cl(-), SO(4)(2-) and CO(3)(2-), showed one group formed by Na(+) and Cl(-), attributed to the discharge of saline water provoked by inundation from a small reservoir, and a second group constituted by Ca(2+), Mg(2+), K(+) and SO(4)(2-), due to an increase provoked by the evaporation in the salinization process.

Comparison of metal analysis in sediments using EDXRF and ICP-OES with the HCl and Tessie extraction methods.

The work presents an investigation on metal availability in sediments during 13 months using the dispersive-energy X-ray fluorescence (EDXRF) and atomic emission spectrometry with induced argon plasma (ICP-OES) techniques and single extraction (0.1moll(-1) HCl) and Tessie's sequential speciation methods. The EDXRF technique could yield essentially the same profile as ICP-OES for the seasonal variation of metals in sediments, but in a more practical way. The sequential extraction procedure (SEP) was more efficient in metal dissolution than single extraction. The Pb, Ni, Al, Cr, and Fe elements were less efficiently extracted with single extraction in relation to sequential extraction. For Co both methodologies were equivalent, but for Cu and Mn the extraction was higher with single extraction. Single extraction does not mobilize Pb, Ni, Al, Cr, and Fe adsorbed on oxides and bound to organic matter. However for Cu and Mn, not only extracted these metals from the four fractions, but it also dissolved part of the fifth fraction (residual). Principal Component Analysis discriminated seasonal variations in the content of several metals, mainly Fe, Co, Ni, and Zn. The mobility of metallic ions in the sediments is conditioned to the seasonal flow of organic and inorganic material coming from the river or by the erosion of adjacent soils.

Simultaneous determination of manganese and selenium in serum by electrothermal atomic absorption spectrometry.

A method for determination of manganese and selenium in serum by simultaneous atomic absorption spectrometry (SIMAAS) is proposed. The samples (30 mul) were diluted (1+3) to 1.0% v/v HNO(3)+0.10% w/v Triton X-100 directly in the autosampler cups. A total of 20 mug Pd+10 mug Mg(NO(3))(2) was used as chemical modifier. The pyrolysis and atomization temperatures for the simultaneous heating program were 1200 and 2300 degrees C, respectively. The addition of an oxidant mixture (15% w/w H(2)O(2)+1.0% v/v HNO(3)) and the inclusion of a low temperature pyrolysis step (400 degrees C) attenuated the build-up of carbonaceous residues onto the integrated platform. An aliquot of 15 mul of the reference or sample solution was introduced into the graphite tube and heated at 80 degrees C; subsequently, 10 mul of oxidant mixture+10 mul of chemical modifier was introduced over that aliquot and the remaining heating program steps were executed. This strategy allowed at least 250 heating cycles for each THGA tube without analytical signal deterioration. The characteristic masses for manganese (6 pg) and selenium (46 pg) were estimated from the analytical curves. The detection limits were 6.5 pg (n=20, 3delta) for manganese and 50 pg (n=20, 3delta) for selenium. The reliability of the entire procedure was checked with the analysis of serum from Seronormtrade mark Trace Elements in Serum (Sero AS) and by addition and recovery tests (97+/-9% for manganese and 96+/-7% for selenium) using five serum samples.