Effect of high hydrostatic pressure on ascorbic acid, phenolic compounds and antioxidant activity of pera rio orange juice

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Stability of Order in Solvent-Annealed Block Copolymer Thin Films

ABSTRACT: One way to produce high order in a block copolymer thin film is by solution casting a thin film and slowly evaporating the solvent in a sealed vessel. Such a solvent-annealing process is a versatile method to produce a highly ordered thin film of a block copolymer. However, the ordered structure of the film degrades over time when stored under ambient conditions. Remarkably, this aging process occurs in mesoscale thin films of polystyrene-polyisoprene triblock copolymer where the monolayer of vitrified 15 nm diameter polystyrene cylinders sink in a 20 nm thick film at 22 °C. The transformation is studied by atomic force microscopy (AFM). We describe the phenomena, characterize the aging process, and propose a semiquantitative model to explain the observations. The residual solvent effects are important but not the primary driving force for the aging process. The study may lead to effective avenue to improve order and make the morphology robust and possibly the solvent-annealing process more effective.

LIFE TABLE ANALYSIS OF DIAPHORINA CITRI (HEMIPTERA: PSYLLIDAE) INFESTING SWEET ORANGE (CITRUS SINENSIS) IN SAO PAULO

An ecological life table for eggs and nymphs of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) was constructed with data obtained from orange orchards (Citrus sinensis Osbeck) in 2 regions of the State of Sao Paulo, over 4 generations in the period from XI-2006 to V-2007, comprising spring, summer, and fall seasons. Young growing shoots with D. citri eggs present were identified, and live individuals were counted until adult emergence. No predatory arthropods were observed in association with D. citri eggs and nymphs during the study. The mean parasitism of fourth- and fifth-instar nymphs by Tamarixia radiata Waterston (Hymenoptera: Eulophidae) was 2.3%. The durations of the egg-adult period were similar among the 4 generations, ranging from 18.0 to 24.7 d (at mean temperatures ranging from 21.6 to 26.0 degrees C) and followed the temperature requirement models obtained in the laboratory for D. citri. However, survival from the egg to the adult stage for the same period varied considerably from 1.7 to 21.4%; the highest mortalities were observed in the egg and small nymphal (first- to thirdinstar) stages, which were considered to be key phases for population growth of the pest.

Epiphany root canal sealer prepared with resinous solvent is irritating to rat subcutaneous tissues

Objective: This study assessed the biocompatibility of the Epiphany endodontic sealer prepared with resinous solvent of Epiphany system (Thinning resin) in rat subcutaneous tissues. Study Design: Polyethylene tubes were filled with the sealer and 4 groups were established: GI, Epiphany prepared with 1 drop of resinous solvent (RS); GII, Epiphany prepared with 1 drop of RS and photoactivated; GIII, Epiphany associated with self-etch primer and prepared with 1 drop of RS; GIV, Epiphany associated with self-etch primer, prepared with 1 drop of RS and photoactivated. The filled tubes were implanted into 4 different regions of the dorsum of 20 adult male rats. Results: After 7, 14 and 21 days, all groups presented a moderate to severe chronic inflammation, necrosis and foreign-body giant cells. At 42 days, although the intensity of chronic inflammatory reaction decreased, the other features still were observed. Conclusion: The Epiphany sealer prepared with the RS was irritating to rat subcutaneous tissues.

Regeneration and characterization of somatic hybrids combining sweet orange and mandarin/mandarin hybrid cultivars for citrus scion improvement

Protoplast fusion between sweet orange and mandarin/mandarin hybrids scion cultivars was performed following the model "diploid embryogenic callus protoplast + diploid mesophyll-derived protoplast". Protoplasts were isolated from embryogenic calli of 'Pera' and 'Westin' sweet orange cultivars (Citrus sinensis) and from young leaves of 'Fremont', Nules', and 'Thomas' mandarins (C. reticulata), and 'Nova' tangelo [C. reticulata x (C. paradisi x C. reticulata)]. The regenerated plants were characterized based on their leaf morphology (thickness), ploidy level, and simple sequence repeat (SSR) molecular markers. Plants were successfully generated only when 'Pera' sweet orange was used as the embryogenic parent. Fifteen plants were regenerated being 7 tetraploid and 8 diploid. Based on SSR molecular markers analyses all 7 tetraploid regenerated plants revealed to be allotetraploids (somatic hybrids), including 2 from the combination of 'Pera' sweet orange + 'Fremont' mandarin, 3 'Pera' sweet orange + 'Nules' mandarin, and 2 'Pera' sweet orange + 'Nova' tangelo, and all the diploid regenerated plants showed the 'Pera' sweet orange marker profile. Somatic hybrids were inoculated with Alternaria alternata and no disease symptoms were detected 96 h post-inoculation. This hybrid material has the potential to be used as a tetraploid parent in interploid crosses for citrus scion breeding.

Seasonal effects on the relationship between photosynthesis and leaf carbohydrates in orange trees

To understand the effect of summer and winter on the relationships between leaf carbohydrate and photosynthesis in citrus trees growing in subtropical conditions, 'Valencia' orange trees were subjected to external manipulation of their carbohydrate concentration by exposing them to darkness and evaluating the maximal photosynthetic capacity. In addition, the relationships between carbohydrate and photosynthesis in the citrus leaves were studied under natural conditions. Exposing the leaves to dark conditions decreased the carbohydrate concentration and increased photosynthesis in both seasons, which is in accordance with the current model of carbohydrate regulation. Significant negative correlations were found between total non-structural carbohydrates and photosynthesis in both seasons. However, non-reducing sugars were the most important carbohydrate that apparently regulated photosynthesis on a typical summer day, whereas starch was important on a typical winter day. As a novelty, photosynthesis stimulation by carbohydrate consumption was approximately three times higher during the summer, i.e. the growing season. Under subtropical conditions, citrus leaves exhibited relatively high photosynthesis and high carbohydrate levels on the summer day, as well as a high nocturnal consumption of starch and soluble sugars. A positive association was determined between photosynthesis and photoassimilate consumption/exportation, even in leaves showing a high carbohydrate concentration. This paper provides evidence that photosynthesis in citrus leaves is regulated by an increase in sink demand rather than by the absolute carbohydrate concentration in leaves.

Genetic transformation of three sweet orange cultivars from explants of adult plants

The difficulty in adult tissue genetic transformation in woody species is still an obstacle to be overcome, including in most sweet orange cultivars of the Brazilian citrus industry. This work reports that, after in vitro culture adjustments, transgenic adventitious buds of 'Hamlin', 'Pra', and 'Valencia' sweet oranges (Citrus sinensis L. Osbeck) were recovered using adult material as explant source, in genetic transformation experiments via Agrobacterium tumefaciens. The transgenic buds were identified by the GUS histochemical analysis and confirmed by PCR analysis, which indicated the presence of an amplified fragment of 817 bp corresponding to the uidA gene sequence. The efficiencies of genetic transformation for 'Hamlin', 'Pra', and 'Valencia' sweet orange cultivars were 2.5, 1.4, and 3.7%, respectively. Media supplemented with auxins and cytokinins during co-culture, and media with high concentrations of cytokinins (3 mg L-1) during transgenic selection led to the transformation and, consequently, the regeneration of adequate number of adventitious buds for the three cultivars. The use of sonication during the explant disinfection was not effective to reduce endophytic contamination and reduced transformation efficiency.

Myelography in orange-spined-hairy-dwarf-porcupine (Sphiggurus villosus)

The myelography procedure is reported in an adult of the Sphiggurus villosus (hairy-tree-porcupine) species coming from the wild, in the region of Curitiba/PR. After proceeding with the examination, while the animal was under general anesthesia, there was a dorsal deviation of the contrast in the height of the seventh thoracic vertebra (T-7) caused by compression in the ventral region of the vertebra. This is suggestive of edema caused by intramedullary hemorrhage secondary to trauma suffered by the animal in the wild. Therefore, the use of myelography in Sphiggurus villosus (hairy-tree-porcupine) proved to be quite valid and efficient, presenting the advantages of greater precision to delimit and locate the lesion present in the vertebral column.

Theoretical study of the absorption and nonradiative deactivation of 1-nitronaphthalene in the low-lying singlet and triplet excited states including methanol and ethanol solvent effects

The photophysics of the 1-nitronaphthalene molecular system, after the absorption transition to the first singlet excited state, is theoretically studied for investigating the ultrafast multiplicity change to the triplet manifold. The consecutive transient absorption spectra experimentally observed in this molecular system are also studied. To identify the electronic states involved in the nonradiative decay, the minimum energy path of the first singlet excited state is obtained using the complete active space self-consistent field//configurational second-order perturbation approach. A near degeneracy region was found between the first singlet and the second triplet excited states with large spin-orbit coupling between them. The intersystem crossing rate was also evaluated. To support the proposed deactivation model the transient absorption spectra observed in the experiments were also considered. For this, computer simulations using sequential quantum mechanic-molecular mechanic methodology was used to consider the solvent effect in the ground and excited states for proper comparison with the experimental results. The absorption transitions from the second triplet excited state in the relaxed geometry permit to describe the transient absorption band experimentally observed around 200 fs after the absorption transition. This indicates that the T-2 electronic state is populated through the intersystem crossing presented here. The two transient absorption bands experimentally observed between 2 and 45 ps after the absorption transition are described here as the T-1 -> T-3 and T-1 -> T-5 transitions, supporting that the intermediate triplet state (T-2) decays by internal conversion to T-1. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4738757]

Natural parasitism of Diaphorina citri Kuwayama (Hemiptera, Psyllidae) nymphs by Tamarixia radiata Waterston (Hymenoptera, Eulophidae) in Sao Paulo orange groves

Natural parasitism of Diaphorina citri Kuwayama (Hemiptera, Psyllidae) nymphs by Tamarixia radiata Waterston (Hymenoptera, Eulophidae) in Sao Paulo orange groves. The psyllid Diaphorina citri Kuwayama 1908 has become the main citrus pest species in the state of Sao Paulo, Brazil, after the introduction of the huanglongbing or citrus greening. This study evaluated the parasitism of 3rd, 4th and 5th instar D. citri nymphs by Tamarixia radiata (Waterston, 1922) in citrus groves under a regimen of regular insecticide applications in ten producing regions: Araraquara, Barretos, Bauru, Botucatu, Franca, Itapetininga, Jau, Limeira, Lins and Sao Joao da Boa Vista. Sixty-nine samples of new branches infested with nymphs of D. citri were collected from 2005 to 2008 in orange groves ranging from 1 to 20 years old, of the varieties Hamlin, Pera, Valencia and Natal. The parasitoid T. radiata is widely distributed in Sao Paulo orange groves, and was identified in 50 (72%) of the samples, showing a mean parasitism rate of 12.4%. The highest parasitism rate was observed in the "summer" (from January through March), with a mean of 25.7%. Nymphal parasitism was above 90% in two samples. The probable causes of the variations in parasitism of D. citri by T. radiata are discussed.

The Role of Molecular Conformation and Polarizable Embedding for One- and Two-Photon Absorption of Disperse Orange 3 in Solution

Solvent effects on the one- and two-photon absorption (IPA and 2PA) of disperse orange 3 (DO3) in dimethyl sulfoxide (DMSO) are studied using a discrete polarizable embedding (PE) response theory. The scheme comprises a quantum region containing the chromophore and an atomically granulated classical region for the solvent accounting for full interactions within and between the two regions. Either classical molecular dynamics (MD) or hybrid Car-Parrinello (CP) quantum/classical (QM/MM) molecular dynamics simulations are employed to describe the solvation of DO3 in DMSO, allowing for an analysis of the effect of the intermolecular short-range repulsion, long-range attraction, and electrostatic interactions on the conformational changes of the chromophore and also the effect of the solute-solvent polarization. PE linear response calculations are performed to verify the character, solvatochromic shift, and overlap of the two lowest energy transitions responsible for the linear absorption spectrum of DO3 in DMSO in the visible spectral region. Results of the PE linear and quadratic response calculations, performed using uncorrelated solute-solvent configurations sampled from either the classical or hybrid CP QM/MM MD simulations, are used to estimate the width of the line shape function of the two electronic lowest energy excited states, which allow a prediction of the 2PA cross-sections without the use of empirical parameters. Appropriate exchange-correlation functionals have been employed in order to describe the charge-transfer process following the electronic transitions of the chromophore in solution.

A simple analysis of the influence of the solvent-induced electronic polarization on the N-15 magnetic shielding of pyridine in water

Electronic polarization induced by the interaction of a reference molecule with a liquid environment is expected to affect the magnetic shielding constants. Understanding this effect using realistic theoretical models is important for proper use of nuclear magnetic resonance in molecular characterization. In this work, we consider the pyridine molecule in water as a model system to briefly investigate this aspect. Thus, Monte Carlo simulations and quantum mechanics calculations based on the B3LYP/6-311++G (d,p) are used to analyze different aspects of the solvent effects on the N-15 magnetic shielding constant of pyridine in water. This includes in special the geometry relaxation and the electronic polarization of the solute by the solvent. The polarization effect is found to be very important, but, as expected for pyridine, the geometry relaxation contribution is essentially negligible. Using an average electrostatic model of the solvent, the magnetic shielding constant is calculated as -58.7 ppm, in good agreement with the experimental value of -56.3 ppm. The explicit inclusion of hydrogen-bonded water molecules embedded in the electrostatic field of the remaining solvent molecules gives the value of -61.8 ppm.

Fractionation of lemon essential oil by solvent extraction: Phase equilibrium for model systems at T=298.2 K

The fractioning of lemon essential oil can be performed by liquid-liquid extraction using hydrous ethanol as a solvent. A quaternary mixture composed of limonene, gamma-terpinene, beta-pinene, and citral was used to simulate lemon essential oil. In this paper, we present (liquid + liquid) equilibrium data that were experimentally determined for systems containing essential oil compounds, ethanol, and water at T = 298.2 K. The experimental data were correlated using the NRTL and UNIQUAC models, and the mean deviations between calculated and experimental data were less than 0.0053 in all systems, indicating the accuracy of these molecular models in describing our systems. The results show that as the water content in the solvent phase increased, the values of the distribution coefficients decreased, regardless of the type of compound studied. However, the oxygenated compound always showed the highest distribution coefficient among the components of the essential oil, thus making deterpenation of the lemon essential oil a feasible process. (C) 2012 Elsevier Ltd. All rights reserved.

Adsorption of Sodium Dodecyl Sulfate on Ge Substrate: The Effect of a Low-Polarity Solvent

This paper describes the adsorption of sodium dodecyl sulfate (SDS) molecules in a low polar solvent on Ge substrate by using Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy and atomic force microscopy (AFM). The maximum SDS amount adsorbed is (5.0 +/- 0.3) x 10(14) molecules cm(-2) in CHCl3, while with the use of CCl4 as subphase the ability of SDS adsorbed is 48% lower. AFM images show that depositions are highly disordered over the interface, and it was possible to establish that the size of the SDS deposition is around 30-40 nm over the Ge surface. A complete description of the infrared spectroscopic bands for the head and tail groups in the SDS molecule is also provided.

Natural parasitism of Diaphorina citri Kuwayama (Hemiptera, Psyllidae) nymphs by Tamarixia radiata Waterston (Hymenoptera, Eulophidae) in São Paulo orange groves

The psyllid Diaphorina citri Kuwayama 1908 has become the main citrus pest species in the state of São Paulo, Brazil, after the introduction of the huanglongbing or citrus greening. This study evaluated the parasitism of 3rd, 4th and 5th instar D. citri nymphs by Tamarixia radiata (Waterston, 1922) in citrus groves under a regimen of regular insecticide applications in ten producing regions: Araraquara, Barretos, Bauru, Botucatu, Franca, Itapetininga, Jaú, Limeira, Lins and São João da Boa Vista. Sixty-nine samples of new branches infested with nymphs of D. citri were collected from 2005 to 2008 in orange groves ranging from 1 to 20 years old, of the varieties Hamlin, Pera, Valencia and Natal. The parasitoid T. radiata is widely distributed in São Paulo orange groves, and was identified in 50 (72%) of the samples, showing a mean parasitism rate of 12.4%. The highest parasitism rate was observed in the "summer" (from January through March), with a mean of 25.7%. Nymphal parasitism was above 90% in two samples. The probable causes of the variations in parasitism of D. citri by T. radiata are discussed.