Determinación simultánea de Cr, Ni y V en orina mediante et aas

A procedure for the simultaneous determination of Cr, Ni, and V in urine by electrothermal atomic absorption spectrometry (ET AAS) was optimized by factorial design, and performed at a pyrolysis and atomization temperatures of 1300 and 2500 ºC, respectively, using 15 µg de Mg(NO3)2 as chemical modifier. Characteristics mass of 14, 6 and 220 ρg and detection limits of the method of 0.07, 0.38 and 0.75 µg L-1 were obtained for Cr, Ni and V respectively. The methodology was validated using a Liphochek Urine Metals Control sample (Bio-Rad) (P=0.05). The methodology was applied to samples of voluntary Venezuelan people, not environmentally exposed to specific emissions, and results ranging from < LOD-1.1 and 1.3-3.3 µg L-1 was observed for Cr and V, respectively, and not detectable levels for Ni.

Uso de diagrama V modificado como relatório em aulas teórico-práticas de química geral

In this article, we present data from a study in practical classes for General Chemistry. To this end, it was proposed to use a modified V diagram to replace traditional reporting. These reports consist of material commonly prepared in the subject, including introduction, materials and methods, results and discussion and conclusions. From the preparation of the modified V, the students were able to establish relationships between the theoretical and methodological aspects necessary for understanding the objects and events studied. Thus, student learning can be evaluated in light of the Theory of Meaningful Learning.

ALCALOIDES ACRIDÔNICOS INIBEM CATEPSINA L E V

Cathepsins represent a class of enzymes that has the primary function of randomly degrading proteins in the lysosomes, although are also involved in different pathologies. The aim of this paper was to evaluate the capacity of acridone alkaloids isolated from Swinglea glutinosa (Rutaceae) to inhibit cathepsin L in vitro . The IC50 values found were in the 0.8-57 µM range and the most promising compounds were alkaloids 1 and 2, with IC50 of 0.9 and 0.8 µM, respectively. Enzyme kinetics revealed that they are reversible competitive inhibitors with respect to the substrate Z-FR-MCA. This small series of acridone alkaloids showed low selectivity for both cathepsins, but represent promising lead candidates for the further development of competitive cathepsin L and V inhibitors.

Revizor : komedija v pjati dejstvijah / sotš. N. Gogolja

Pultavan kuvernementista, Ukrainan alueelta kotoisin oleva Nikolai Gogol (1809-1852) kävi kahdeksan vuotta Nizhynin taidekoulua. Sinä aikana hän alkoi myös kirjallisen työnsä. Vuonna 1828 hän muutti Pietariin ja tutustui Venäjän kirjalliseen aristokratiaan, mm. Alexander Pushkiniin. Vuonna 1831 ilmestyi ensimmäinen nide Ukrainaan liittyvistä kertomuksista, Vetshera na hutore bliz Dikanki. Gogol oli syvästi kiinnostunut Ukrainan historiasta ja pyrki Kiovan yliopiston historian osaston virkaan. Silloinen Venäjän opetusministeri Sergei Uvarov ja Pushkin tukivat häntä, mutta Kiovan byrokraatit pitivät Gogolia epäpätevänä. Kiovan sijaan Gogol sai vuonna 1834 viran Pietarin yliopiston keskiajan historian professorina, jossa virassa hän todella olikin epäpätevä. Gogol erosi virasta jo seuraavana vuonna. Gogol alkoi uskoa omiin kirjallisiin kykyihinsä, kun hänen komediansa Revizor esitettiin huhtikuussa 1836. Teos on rankkaa satiiria Venäjän provinssien byrokraateista, ja se saatiin esittää vain Nikolai I:n väliintulon kautta. Näytelmä esitti koko Venäjän yhteiskunnan kaikkine ongelmineen, ja oli selvää, että se aiheutti kiistoja. Näitä Gogol pakeni ulkomaille, ja Roomassa syntyivät ensimmäiset osat teoksista Kuolleet sielut sekä Päällysnuttu.

1000 V jakelujännitteen käyttömahdollisuudet Kymenlaakson Sähköverkko Oy:ssä

Kymenlaakson Sähköverkko Oy:n 20/0,4 kV tekniikalla toteutettu sähkönjakeluverkko on monin paikoin saavuttamassa pitoaikansa loppua. Sähkönjakeluverkko sijaitsee pääasiassa haja-asutusalueilla ja on pääosin avojohtotekniikalla rakennettua. Haja-asutusalueilla 20 kV sähköverkko sisältää paljon lyhyitä 1–5 km pituisia johtohaaroja. Tässä diplomityössä selvitettiin 20/1/0,4 kV sähkönjakelujärjestelmän käyttömahdollisuuksia Kymenlaakson Sähköverkko Oy:n sähkönjakeluverkossa. Työssä vertailtiin erilaisilla verkostoratkaisuilla saatavia elinkaarikustannuksia perusparannus- ja uudisrakennuskohteissa. Tutkimuksen perusteella Kymenlaakson Sähköverkko Oy:n sähkönjakeluverkossa on potentiaalia 1000 V jakelujännitteen käytölle. Työssä perehdyttiin myös 1000 V verkostokomponenttien merkitsemiseen ja verkkoyhtiön tekemiin 1000 V verkon tarkastuksiin.

Miniatures V

Soitinnus: piano.

Contribuciones a la ictiologia: V - VI sobre algunas especies de Gobiidae de la colección del Laboratorio Aragó (Banyuls-sur-mer, Francia) y descripción de un nuevo genero (Austrogobius) sudamericano

En el número V de "Contribuciones a la Ictiologia" se dán normas para el estudio sistemático de los organos ciatiformes, que proporcionaron a los Gobiidae de Europa un medio seguro de ordenación genérica y distinción específica. Se añade el estudio de la colección del Laboratorio Aragó, de Banyuls-sur-mer, Francia. En el número VI de "Contribuciones a la Ictiología" se aloja el Gobiosoma parri Ginsburg en el nuevo gênero Austrogobius De Buen, y se dán las características que lo distinguen, especialmente la distribución de tubos mucosos y geniporos.

Spectroscopic analysis of C80 doping with group III and group V elements using semiempirical PM3 molecular modelling technique

Semiempirical calculations at the level of PM3 of theory were carried out to study the structural and electronic properties of C80 and some of its doped derivatives with the elements of group III and V at the level of PM3 of theory. We have selected these elements to be substituted in the fullerene-C80 cage in order to show the effect of such structural change on the electronic properties of the molecules studied. The theoretical IR spectra, some of physical and chemical properties of the molecules studied are obtained and discussed.

A novel indicator reaction for the catalytic determination of V(V) at ppb levels by the kinetic spectrophotometric method

A novel sensitive and relatively selective kinetic method is presented for the determination of V(V), based on its catalytic effect on the oxidation reaction of Ponceau Xylydine by potassium bromate in presence of 5-sulfosalicylic acid (SSA) as activator. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of Ponceau Xylydine at 640 nm between 0.5 to 7 min (the fixed time method) in H3PO4 medium at 25ºC. The effect of various parameters such as concentrations of H3PO4, SSA, bromate and Ponceau Xylydine, temperature and ionic strength on the rate of net reaction were studied. The method is free from most interferences, especially from large amounts of V(IV). The decrease in absorbance is proportional to the concentration of V(V) over the entire concentration range tested (1-15 ng mL−1) with a detection limit of 0.46 ng mL-1 (according to statistical 3Sblank/k criterion) and a coefficient of variation (CV) of 1.8% (for ten replicate measurement at 95% confidence level). The proposed method suffers few interferences such as Cr(VI) and Hg(II) ions. The method was successfully applied to the determination of V(V) in tap water, drinking water, bottled mineral water samples and a certified standard reference material such as SRM-1640 with satisfactory results. The vanadium contents of water samples were also determined by FAAS for a comparison. The recovery of spiked vanadium(V) was found to be quantitative and the reproducibility was satisfactory. It was observed that the results of the SRM 1640 were in good agreement with the certified value.