Public-domain software for root image analysis

In the search for high efficiency in root studies, computational systems have been developed to analyze digital images. ImageJ and Safira are public-domain systems that may be used for image analysis of washed roots. However, differences in root properties measured using ImageJ and Safira are supposed. This study compared values of root length and surface area obtained with public-domain systems with values obtained by a reference method. Root samples were collected in a banana plantation in an area of a shallower Typic Carbonatic Haplic Cambisol (CXk), and an area of a deeper Typic Haplic Ta Eutrophic Cambisol (CXve), at six depths in five replications. Root images were digitized and the systems ImageJ and Safira used to determine root length and surface area. The line-intersect method modified by Tennant was used as reference; values of root length and surface area measured with the different systems were analyzed by Pearson's correlation coefficient and compared by the confidence interval and t-test. Both systems ImageJ and Safira had positive correlation coefficients with the reference method for root length and surface area data in CXk and CXve. The correlation coefficient ranged from 0.54 to 0.80, with lowest value observed for ImageJ in the measurement of surface area of roots sampled in CXve. The IC (95 %) revealed that root length measurements with Safira did not differ from that with the reference method in CXk (-77.3 to 244.0 mm). Regarding surface area measurements, Safira did not differ from the reference method for samples collected in CXk (-530.6 to 565.8 mm²) as well as in CXve (-4231 to 612.1 mm²). However, measurements with ImageJ were different from those obtained by the reference method, underestimating length and surface area in samples collected in CXk and CXve. Both ImageJ and Safira allow an identification of increases or decreases in root length and surface area. However, Safira results for root length and surface area are closer to the results obtained with the reference method.

Bisfosfonatos: síntese, análises químicas e aplicações farmacológicas

Bisphosphonates are drugs that have been widely used in different bone diseases, and have recently been used successfully against many parasites. Various synthetic routes to prepare different types of bisphosphonates have been described, with distinct potency and pharmacological activity. A number of analytical techniques are currently being used to analyze these drugs; among these, the high performance liquid chromatography (HPLC), with different systems of detection, is worth highlighting. However, the development of more sensitive methods is still necessary, once they are essential for bioavailability and bioequivalence studies. This paper reports the major synthesis routes, chemical analysis methodologies and pharmacological applications of bisphosphonates.

Uso de artigos científicos em uma disciplina de Físico-Química

This paper describes the use of primary chemistry literature in a fifth-semester physical chemistry course for undergraduate chemistry students. The main goal is to expose students to the primary literature of physical chemistry, demonstrating how they can benefit from using it. The assignment addresses issues in chemical education such as scientific writing, relating lecture material to the real world, and conducting literature searches. The student evaluation of this assignment, consisting of two surveys and one focus group, showed its usefulness. The details of the evaluation instruments and their results are provided. Out of 45 students enrolled in the course, 30 (67%) students completed the assignment.

Carotenoids production: microorganisms as source of natural dyes

Carotenoids are natural dyes synthesized by plants, algae and microorganisms. Application in many sectors can be found, as food dyeing and supplementation, pharmaceuticals, cosmetics and animal feed. Recent investigations have shown their ability to reduce the risks for many degenerative diseases like cancer, heart diseases, cataract and macular degeneration. An advantage of microbial carotenoids is the fact that the cultivation in controlled conditions is not dependent of climate, season or soil composition. In this review the advances in bio-production of carotenoids are presented, discussing the main factors that influence the microbial production of these dyes in different systems.

Quantificação dos isômeros ácido L-ascórbico e ácido D-iso-ascórbico em geleias de frutas por cromatografia líquida de alta eficiência

Ascorbic acid has important nutritional characteristics such as high antioxidant potential, preventing diverse damage and diseases in the tissues and the process of aging. Different isomeric forms of the ascorbic acid can be found in nature and each one have different potential antioxidant and different activity pro-vitamin C. This work examined a method to detect and quantify the isomers L-ascorbic acid (LAA) and D-iso-ascorbic acid (DIAA) in jelly fruit. The method showed acceptable selectivity, linearity, repeatability and recovery. DIAA was not found in the analyzed samples, but LAA was found up to 605 mg in 100 g of sample.

Constituintes químicos dos galhos de Simaba guianensis subesp. ecaudata (Cronquist)

Simaba guianensis subesp. ecaudata (Simaroubaceae) is a tree found in the Brazilian Amazon. This work describes for the first time the fractionation of stems of this species that resulted in the isolation of the cytotoxic triterpene piscidinol A, the alkaloid 9-methoxycanthin-6-one, caryophyllene oxide, also isolated for the first time from this species and a new alkaloid (6-methoxy-(9H-β-carbolin-1-il)-(Z)-2-propenoic acid). Quantification of 9-methoxycanthin-6-one in different extracts and fractions of stems of S. guianensis by high performance liquid chromatography was also performed. The concentration of 9-methoxycanthin-6-one in methanolic and aqueous extracts were inferior to the known cytotoxic concentration of this compound.

CASOS INVESTIGATIVOS E A RELAÇÃO COM O SABER: TRAJETÓRIA E PROCESSO DE APRENDIZAGEM DE ESTUDANTES DO ENSINO SUPERIOR NO TOCANTINS

In light of the theory of relationship with know of Bernard Charlot, aiming to understand the unique stories of the subject through a positive lecture, i.e., understanding the reality and the way the subjects read and interpret the world, this article attempts identify how higher education students solve an investigative case and learn the scientific knowledge using this theory. For this, we used narrative as a discourse genre to collect the data of 34 students who participated in the small group activities. After content analysis, the results showed that all groups of students solve the case in a similar way and in three stages, prevailing relations with know with the world, with others and with yourself. However, even if the resolution is similar, chemical learning differs between different groups and differs between the scientific content present in the case. From these results it is possible to identify the effectiveness of learning depends on the epistemic and identity relationships with know of each subject (relationship with yourself) because to learn the student must enter into an intellectual activity (investigative case), stay on it and develop the relationships with known necessary to master the normativity (chemical language).

The effect of wood supply and bleaching process on pulp brightness stability

One hundred different 5.5-year-old Eucalyptus grandis x Eucalyptus urophylla wood clones were cooked to kappa number 15-17.5 and the resulting kraft pulps oxygen-delignified to kappa 9.5-11.5 under fixed conditions, except for chemical charges. Thirteen samples showing large variations in effective alkali requirement, pulp yield and O-stage efficiency and selectivity were selected for brightness reversion studies. These samples were bleached to 90-91% ISO by DEDD and DEDP sequences and their brightness stability and chemical characteristics determined. Heat reversion of the eucalyptus kraft pulps was strongly influenced by the wood supply, with brightness loss varying in the range of 2.1-3.6 and 0.8-1.7 %ISO for ODEDD and ODEDP bleached pulps, respectively. Pulps bleached by the ODEDP sequence showed reversion values 1.3-1.9 % ISO lower than those bleached by the ODEDD sequence. Pulp carbonyl content decreased by 35-40% during the final peroxide bleaching stage. Carbonyl and carboxyl groups correlated positively with brightness reversion, as did permanganate number and acid soluble lignin. Pulp final viscosity and metal and DCM extractives contents showed no significant correlation with brightness reversion. Pulping, oxygen delignification and ECF bleaching performances also showed no correlation with brightness reversion.

Comparison of metering mechanisms of corn seed

It was compared the performance of the metering mechanism of corn seeds (Zea mays) in direct seeding in an area of ​​200 ha, a property in Piraí do Sul, State of Paraná - PR, in Brazil. It was seeded 4 maize hybrids, 50 ha of each, with seeds of different sieves. The experiment was conducted in a randomized block design (RBD), with 3 treatments and 9 repetitions for each corn hybrid. The treatments were the pneumatic seed of metering mechanisms, horizontal perforated disc with and without ramp®. The plots were 40 m² and were distributed at the early, middle and late sowing. The variables analyzed in each corn hybrid were initial population, faulty spacing, multiple spacing, acceptable spacing, and yield components. As there were no significant differences in the variables, it was concluded that the quality of seeding with different systems of distribution was similar in the different sieves of distributed corn seeds.

Expression of the Mycobacterium bovis P36 gene in Mycobacterium smegmatis and the baculovirus/insect cell system

In the present study we evaluated different systems for the expression of mycobacterial antigen P36 secreted by Mycobacterium bovis. P36 was detected by Western blot using a specific antiserum. The P36 gene was initially expressed in E. coli, under the control of the T7 promoter, but severe proteolysis prevented its purification. We then tried to express P36 in M. smegmatis and insect cells. For M. smegmatis, we used three different plasmid vectors differing in copy number and in the presence of a promoter for expression of heterologous proteins. P36 was detected in the cell extract and culture supernatant in both expression systems and was recognized by sera from M. bovis-infected cattle. To compare the expression level and compartmentalization, the MPB70 antigen was also expressed. The highest production was reached in insect cell supernatants. In conclusion, M. smegmatis and especially the baculovirus expression system are good choices for the production of proteins from pathogenic mycobacteria for the development of mycobacterial vaccines and diagnostic reagents.

Banking and regional inequality in Brazil: an empirical note

The paper investigates a neglected aspect of regional inequality in Brazil, namely regional inequalities related to financial flows. A synthetic regional financial inequality index is proposed and calculated in a semester basis over the 02-1994/02-2000 period. The inequality measure attempts to capture to what extent deposits in a given state translate into credit operations in that locality. Two main results emerge. First, non-negligible inequality patterns emerge when one considers the segment of private banks and those are consistent with an important proportion of states with a predominantly exporting pattern, for which deposits surpasses loans in that locality. Second, if one focus on the segment of public banks, an opposite pattern appears, that is consistent with decision patterns that might have, in part, a regional development motivation.