Eudragit E100/poly(ethylene oxide) electrospun fibers for DNA removal from aqueous solution

The development of new strategies for production of low-cost deoxyribonucleic acid (DNA) adsorbents based on electrospun fibers of block copolymers [Eudragit E-100/poly(ethylene oxide) (PEO)] is a promising way for fast retrieval of free of degradation double-stranded DNA chains from aqueous solution. The adsorption takes place through electrostatic interaction between DNA and oppositely charged electrospun fibers that provide high surface area for DNA adsorption. The adsorption capacity observed for electrospun fibers of Eudragit E100/PEO (considering as target molecules the salmon sperm DNA) was in order of 44.31 mg g⁻¹, following the Langmuir model in a typical adsorption at solid/liquid interface (pseudo-second-order model), that characterizes the electrospun fibers as promising templates for removal of biologic components and further use in molecular biology techniques, as DNA amplification by polymerase chain reaction. The reuse and integrity of membranes after long period of adsorption were tested, confirming the potential of material as adsorbent. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47479.     

Irreversible thermodynamics analysis of ellipsoidal wheat kernel drying,aiming at the evaluation of phenomenological properties

Literature data have revealed that wheat kernel stress–strain relationships, thermal conductivity, and specific heat support the assumption of isotropy. Accepting this premise, we show that drying complexity can be reduced by properly defining the kernel shape and an accurate model. Therefore, we present an irreversible thermodynamics procedure for obtaining transport properties of a wheat kernel. The numerical solution of the associated nonlinear conservation equations was based on the Radial Basis Functions method. Drying behavior of both prolate ellipsoidal and spherical grain kernels is presented and compared. The predicted moisture and temperature profiles correlated favorably with experimental drying profiles, obtained for two temperatures of 47 and 67.5°C.     

Oxidative stress and acid–base balance during the transition period of neonatal Holstein calves submitted to different calving times and obstetric assistance

During the neonatal period, constant adaptations to the extrauterine environment are required. These adaptations are made impossible or hindered when unexpected obstetrical events take place. This study aimed to identify clinical changes of vitality, metabolic and acid–base balance, and oxidative stress of newborn calves born to assisted dams that experienced different durations of calving. A prospective and observational study was conducted with 44 Holstein calves allocated to 3 groups according to the duration of calving: 2?h (n = 16), 2–4?h (n = 16), and >4?h (n = 12), and to 2 subgroups: spontaneous calving (n = 22) and assisted calving (n = 22). We observed that obstetric assistance was beneficial when calving lasted more than 4 h, because 100% of assisted calves had a high Apgar score (≥7) at 5?min, similar to that of spontaneously born calves after 2?h of calving. Rectal temperature of all calves remained within normal values, albeit with a reduction at 20 min of life. Calves born after a calving time >4 h had the highest rectal temperatures, especially those that required obstetrical assistance. There was a progressive increase in blood oxygenation with time, but calves in the >4?h group showed the highest partial pressure of carbon dioxide at birth, whereas calves in the 2 h and 2–4 h groups had lower values. A decrease in partial pressure of CO₂ was observed at 120 min in the 2–4?h and >4?h groups. In the 2–4?h group, calves with obstetrical assistance had higher oxidative stress (measured as thiobarbituric acid reactive substances, TBARS) at 120 min of life compared with that at birth. In spontaneously born calves, TBARS increased only after 240?min. In the >4?h group, TBARS increased progressively with time, regardless of obstetrical subgroup. Calves born spontaneously within the 2?h group had higher TBARS values at birth than calves in the >4 h group with obstetrical assistance. Calves in the >4?h group showed higher levels of glutathione peroxidase (an antioxidant enzyme) at birth than those in the remaining groups. Glutathione peroxidase decreased at 120?min in the >4?h group and at 240?min for the 2?h and 2–4?h groups. In conclusion, obstetric assistance did not improve neonatal vitality and blood oxygenation when calving lasted less than 2 h. Calves born after 2 h of calving showed decreased vitality, hypercapnia, hypoxemia, and increased antioxidant status (glutathione peroxidase).     

Mercury distribution, speciation and flux in the Sepetiba Bay tributaries, SE Brazil

Dissolved gaseous Hg, reactive Hg, total dissolved Hg and particulate Hg concentrations were measured in samples of majors tributaries of the Sepetiba Bay, SE Brazil (Itimirim, Itingu?u, Guarda, Guandu, S?o Francisco and Ita rivers), in dry and rainy seasons. The average Hg concentrations found varied from 0.02 to 0.18 ng L(-1) for dissolved gaseous Hg, from 0.1 to 18.1 ng L(-1) for reactive Hg, from 0.1 to 66.6 ng L(-1) for total dissolved Hg and from 0.3 to 250 ng L(-1) for particulate Hg. During the rainy season, a decrease in the dissolved Hg concentrations and an increase in the particulate Hg concentrations was observed. Positive correlations were found between the reactive Hg and the total dissolved Hg concentrations (r = 0.99), between the particulate Hg and TSS concentrations (r = 0.82) and between total Hg and particulate Hg concentrations (r = 0.95). The instantaneous Hg fluxes varied among rivers from 0.02 to 412 microgs(-1) for total dissolved Hg and from 0.03 to 12,572 microgs(-1) for particulate Hg. The log Kd varied from 3.76 to 6.43 and showed a significant increase in rainy season following an increase in particulate Hg and a decrease in dissolved Hg concentrations. These results suggest that erosion and runoff are the major pathways of Hg transport to rivers and eventually to Sepetiba Bay.     

Nonuniform coherence sampling for fields produced by incoherent three-dimensional sources

A nonuniform sampling scheme is described for measuring the mutual intensity of the wave field produced in a plane a distance z from a spatially incoherent, three-dimensional source object. Both uniform and nonuniform sampling are analyzed and discussed in detail, and comparisons of the two schemes are made. It is shown that nonuniform sampling requires fewer measurements than uniform sampling to specify the coherence function. Additionally, the smallest separation required between measurement points is larger for the nonuniform case.     

Synthesis and Antitrypanosomal Activity of 1,4-Disubstituted Triazole Compounds Based on a 2-Nitroimidazole Scaffold: a Structure-Activity Relationship Study

Chagas disease affects 6–8 million people worldwide, remaining a public health concern. Toxicity, several adverse effects and inefficiency in the chronic stage of the disease are the major challenges regarding the available treatment protocols. This work involved the synthesis of twenty-two 1,4-disubstituted-1,2,3-triazole analogues of benznidazole (BZN), by using a click chemistry strategy. Analogues were obtained in moderate to good yields (40-97 %). Antitrypanosomal activity was evaluated against the amastigote forms of Trypanosoma cruzi. Compound 8 a (4-(2-nitro-1H-imidazol-1-yl)methyl)-1-phenyl-1H-1,2,3-triazole) without substituents on phenyl ring showed similar biological activity to BZN (IC₅₀=3.0 μM, SI>65.3), with an IC₅₀=3.1 μM and SI>64.5. Compound 8 o (3,4-di-OCH₃−Ph) with IC₅₀ = 0.65 μM was five-fold more active than BZN, and showed an excellent selectivity index (SI>307.7). Compound 8 v (3-NO₂, 4-CH₃−Ph) with IC₅₀=1.2 μM and relevant SI>166.7, also exhibited higher activity than BZN. SAR analysis exhibited a pattern regarding antitrypanosomal activity relative to BZN, in compounds with electron-withdrawing groups (Hammett σ+) at position 3, and electron-donating groups (Hammett σ-) at position 4, as observed in 8 o and 8 v . Further research might explore in vivo antitrypanosomal activity of promising analogues 8 a , 8 o , and 8 v . Overall, this study indicates that approaches such as the bioisosteric replacement of amide group by 1,2,3-triazole ring, the use of click chemistry as a synthesis strategy, and design tools like Craig-plot and Topliss tree are promising alternatives to drug discovery.     

Acetaldehyde and formaldehyde concentrations from sites impacted by heavy-duty diesel vehicles and their correlation with the fuel composition: Diesel and diesel/biodiesel blends

The increasing of both industrialization and motorization of the world has led to a sharp rise in the demand for fossil fuels. Concern about the environmental impact caused by burning of these fuels has involved researchers that became engaged in assessing the damages of pollution not only to environment, but also to human health. In this study, carbonyl compounds (CC) were measured in vapor samples from a place impacted by heavy-duty vehicles (Bus Station) fuelled with diesel/biodiesel fuel blend (B5) in Salvador, Brazil. Among them, formaldehyde, acetaldehyde and propanone were the most abundant quantified compounds. Concentration levels (ppbV) for major CC detected during the sampling period ranged from 28.45 to 287.3 (formaldehyde), 24.91 to 171.3 (acetaldehyde) and 5.835 to 72.29 (propanone). The obtained data in this site was compared to formaldehyde and acetaldehyde concentrations found in other sites impacted by heavy-duty vehicles fuelled with pure diesel and diesel/biodiesel blends. All data were used to make a possible correlation with formaldehyde/acetaldehyde ratio and the relationship with the kind of fuel used by these vehicles. PCA was used to verify possible grouping among 19 sites impacted by heavy-duty vehicles and showed two major groups, one characterized by being strongly impacted and the other with a low contribution of heavy-duty vehicles. Thus, the addition of higher concentrations of biodiesel to diesel showed an improvement in the carbonyl concentration profile at places with high circulation of heavy-duty vehicles, which had similar profile to those found for sites less impacted by these kind of vehicles.