Preparation and characterization of porous microspheres and applications in controlled-release of abamectin in water and soil

Porous microspheres with different sizes were prepared through solvent evaporation method with ethylcellulose as a matrix material and abamectin as a core material. The abamectin-loaded microspheres were characterized through scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The chemical structure of the microspheres was determined through FTIR. DLS analysis showed that the diameter of the microspheres range from 10 to 100 μm. SEM analysis revealed that the inner structure of the microspheres is characterized by a porous network. TGA revealed that the microspheres are thermally stable below 125 °C. The controlled release of abamectin from the microspheres into water and soil was also investigated. Abamectin was released from microspheres into water through diffusion. The release of abamectin into soil was mainly caused by erosion, a result that was verified through SEM.     

Study of phase separation in blends of silk fibroin and sodium alginate in solution and in solid state

Silk fibroin (SF) and sodium alginate (SA) are natural polymers with many applications as biomaterials. It is possible to make blends with them in order to improve their properties. Those blends are partially miscible; therefore, understanding the mechanism and phase equilibrium of this system is important to better understand the interaction between these natural polymers. This work analyzed the mechanism of phase separation of SF and SA blends with different composition in solution and in the solid state (as membranes) using small angle light scattering with a He-Ne laser. Polymer interaction and conformation were investigated by Fourier-Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR) and X-Ray Diffraction (XRD), and membrane morphology was analyzed by Scanning Electron Microscopy (SEM). SEM images showed interpenetrated globules in the matrix. Light scattering profile for blends in solution and in the solid state showed a peak of intensity suggesting that phase separation occurs by spinodal decomposition.     

Toxicity profiles in vivo in mice and antitumour activity in tumour-bearing mice of di- and triorganotin compounds

The in vivo toxicity profiles in mice and the antitumour activity in tumour bearing mice were screened for four di-n-butyltin and five triorganotin carboxylates, di-n-butyltin diterebate (5), bis(phenylacetate) (6), bis(deoxycholate) (7), bis(lithocholate) (8), tri-n-butyltin terebate (9), cinnamate (10), and triphenyltin terebate (11).At their maximum tolerated dosis (MTD), no antitumour effect (T/C ~1) was observed for the compounds 5, 7, 9, 10 and 11. The compounds 6 (T/C = 0.51) and 8 (T/C = 0.42) showed clear antitumour activity after single dose administration and might therefore be of interest for further antitumour activity studies.     

Inter- and Intraspecific Variations in Production of Spines and Phenols in Prosopis caldenia and Prosopis flexuosa

In central Argentina the leguminous tree Prosopis caldenia is more abundant in sites of relatively high productivity (lowlands), whereas P. flexuosa is more abundant in sites of relatively low productivity (slopes and uplands). Based upon current antiherbivore defense theory, we predicted: (1) a higher investment in defenses in P. flexuosa than in P. caldenia, and (2) that limitations in resources would result in an increase of the defenses in both species. Our approach for testing these predictions was to estimate leaf phenol concentration and spinescence in adults (field study) and seedlings (greenhouse study) of both species growing at different levels of resource availability. In adult plants, the concentration of phenols was higher (P < 0.01) in P. flexuosa than in P. caldenia, but the opposite relationship was observed in seedlings. The amount of biomass invested in spines was similar (P > 0.10) in both species, whereas spine density was higher (P < 0.05) in P. caldenia than in P. flexuosa. In both species, limitations in resources did not result (P > 0.05) in increases in leaf phenol concentration, amount of biomass invested in spines, spine length, or spine density, except for the increase (P < 0.05) of spine density in seedlings of P. caldenia at low water and nutrient availability. In general, our results did not support current hypotheses on the production of antiherbivore defenses. It is argued that factors such as herbivore behavior (e.g., habitat selection, trampling, branch breakage) and alternative sinks for carbon (e.g., N₂ fixation, carbohydrate reserves), in addition to resource availability in evolutionary and ecological time, should be considered for a more complete understanding of the inter- and intraspecific variations in the production of both physical and chemical antiherbivore defenses.     

In vitro and in vivo Digestibility of Blended and Corresponding Interesterified Fats in Rats

The process of interesterification of fat blends namely vanaspati-ground-nut oil (40:60) (vanaspati-GNO), sal fat and groundnut oil (30:70) (sal-GNO), sheep tallow and groundnut oil (30:70) (ST-GNO), and cottonseed oil (CSO) was found to bring about limited but consistent increase in in vitro digestibility (compared to starting stocks) during first four hours studied. Apparent digestibility of blends of sal-GNO and vanaspati-GNO in rats was not effected by the process of interesterification while interesterified products had significantly higher in vivo true digestibility compared to starting stocks.     

Radiation polymerization and crosslinking of (N-isopropylacrylamide) in solution and in solid state

Summary N-isopropylacrylamide (NIPAAm) hydrogels were synthesized by means of gamma irradiation, with three different methods: (a) irradiation of NIPAAm aqueous solutions; (b) irradiation of NIPAAm aqueous solution in presence of crosslinking agent N, N’-methylenebisacrylamide (BIS); and (c) in solid state, in form of disks compacted at different pressures prior to irradiation. Hydrogels of different crosslinking morphology were generated under different conditions. The hydrogels were characterized with regard to their gel content, swelling behavior in dependence on the temperature, and network properties. Morphology of the samples was characterized by SEM.     

Mycoflora and Co-Occurrence of Fumonisins and Aflatoxins in Freshly Harvested Corn in Different Regions of Brazil

Natural mycoflora and co-occurrence of fumonisins (FB₁, FB₂) and aflatoxins (AFB₁, AFB₂, AFG₁ and AFG₂) in freshly harvested corn grain samples from four regions of Brazil were investigated. Fusarium verticillioides was predominant in all samples. Analysis of fumonisins showed that 98% of the samples were contaminated with FB₁ and 74.5% with FB₁ + FB₂, with toxin levels ranging from 0.015 to 9.67 μg/g for FB₁ and from 0.015 to 3.16 μg/g for FB₂. Twenty-one (10.5%) samples were contaminated with AFB₁, seven (3.5%) with AFB₂ and only one (0.5%) with AFG₁ and AFG₂ Co-contamination with aflatoxins and fumonisins was observed in 7% of the samples. The highest contamination of fumonisins and aflatoxins was observed in Nova Odessa (SP) and Várzea Grande (MT), respectively. The lowest contamination of these mycotoxins was found in Várzea Grande and Nova Odessa, respectively.     

Seasonal Variations in the Fatty Acid Composition of Phospholipid and Triacylglycerol in Gonad and Liver of Mastacembelus simack

The seasonal effects on the fatty acid composition of triacylglycerol (TG) and phospholipid (PL) in the gonad and liver of Mastacembelus simack were determined using the gas chromatographic method. The most abundant fatty acids in the investigated seasons and tissues were palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1n‐9), palmitoleic acid (C16:1n‐7), arachidonic acid (C20:4n‐6), eicosapentaenoic acid (C20:5n‐3), and docosahexaenoic acid (C22:6n‐3). The distribution proportions of ∑SFA (saturated fatty acids), ∑MUFA (monounsaturated fatty acids) and ∑PUFA (polyunsaturated fatty acids) were found to be different among PL and TG fractions in all seasons. The total lipid content of gonad and liver were 1.32 (November)–4.90 % (September) and 1.32 (September)–3.94 % (January), respectively. It was shown that the total lipid and fatty acid compositions in the gonad and liver of fish were significantly influenced by seasons.     

Cathodic reduction of benzil in acetone and in dichloromethane

The cathodic reduction of benzil has been carried out at a controlled potential on a mercury cathode in two different SSE (solvent-supporting-electrolyte) conditions: (a) acetone/lithium perchlorate in absence of electrophile where 2,3-diphenyl-5-methyl-furan and 1,2-diphenyl-2-hydroxy-1,4-pentanedione were obtained as main products and (b) dichloromethane/tetrabuthylammonium chloride with the addition of oxalyl chloride as electrophile, where a fast electron transfer took place.     

我国氮氧化物排放控制及脱硝催化剂研究进展

氮氧化物(NOx)对大气环境造成的危害已成为影响生态环境和经济社会可持续发展的重要因素,其来源主要集中在火电、玻璃、陶瓷、水泥、钢铁和焦化行业等固定污染源以及机动车、船舶和飞机等移动污染源。实践表明,催化脱硝是NOx减排的最有效手段。介绍我国NOx污染现状,并结合不同领域和行业的烟气特点,阐述NOx的治理情况和研究难点。在此基础上,围绕NOx催化消除这一共性问题,根据不同行业间实际工况的共性和差异性,分别以NH_3-SCR(固定源脱硝)和NO+CO(移动源脱硝)两种催化脱硝技术为主线,系统综述固定源(中高温、低温、抗中毒)及移动源(汽油车和柴油车)中脱硝催化剂的研究进展,并对不同领域相应脱硝催化剂可能的发展方向进行展望。     

Occurrence of Deoxynivalenol in Maize and Wheat in Serbia

A total of 226 samples of maize and 59 of wheat from the 2004–2007 harvests were investigated for the presence and concentration of deoxynivalenol (DON). Samples of the 2004 harvest were analyzed after their storing for one year in barns, while those of the 2005–2007 harvest were taken directly off fields immediately after the harvest. The samples were analyzed by liquid chromatography on an ODS Hypersil column with DAD detector and ELISA methods. The average incidence rate of DON in maize from the 2004 harvest was 50% (concentration range 0.042–2.460 mg/kg, average value 0.536 mg/kg), while for those of the 2005–2007 harvest it was 32.4% (concentration range 0.027–2.210 mg/kg, average value 0.223 mg/kg). In the case of wheat incidence rate of DON for 2004 harvest was 50.0% (concentration range 0.630–1.840 mg/kg, average value 1.235 mg/kg), while for those of the 2005–2007 harvest it was 34.5% (concentration range 0.057–0.423 mg/kg, average value 0.190 mg/kg). Concentrations in two samples of maize and one of wheat (one sample of each cereal being of the 2004 harvest) were above the maximum level adopted by the European Commission. The results obtained were analyzed as a function of climatic conditions and compared with those of the neighboring countries where the relevant data existed.     

紫背天葵黄酮的体内外抗氧化作用

采用体积分数80%的乙醇提取紫背天葵中的总黄酮并测定其含量,将粗提液萃取,经AB-8型大孔吸附树脂纯化,以Vc为对照,测定紫背天葵总黄酮粗提液、纯化液对二苯代苦味酰基自由基(DPPH.)、羟基自由基(.OH)和超氧阴离子自由基(O2-.)的清除能力,并考察紫背天葵黄酮纯化物的体内抗氧化效果。结果表明,紫背天葵中粗黄酮含量为13.928 mg/g,纯化比率为32.79%;紫背天葵总黄酮粗提液、纯化液对3种自由基均有不同程度的清除作用,且清除作用随黄酮质量浓度的升高而增强,纯化液的清除作用强于粗提液;低剂量紫背天葵黄酮纯化物实验组小鼠肝脏和脑组织中超氧化物歧化酶(SOD)活力和肝脏过氧化氢酶(CAT)活力显著高于对照组(p<0.05),而脑中的丙二醛(MDA)含量显著低于正常对照组(p<0.05)。     

Evaluation and characterization of vector fluids and peroxides in a process of in situ compatibilization of polyethylene and polystyrene

An organic functional silane was found to be the most efficient among several vector fluids in reactive blend compatibilization of the polyethylene (PE) / polystyrene (PS) / peroxide / vector fluid system. This paper involves further analysis of this reactive blending system. Surface tension data was used to calculate spreading coefficients which were compared to the amount of PE-PS copolymer formed during blending. A good correlation between a computed spreading coefficient and the degree of grafting of PS onto PE was found. The results suggest that the pattern of distribution of the vector fluid in PE / PS blends is the key factor leading to effective results. Furthermore, different peroxides were evaluated in PE / PS blends, in order to determine the dependence of PE / PS interfacial grafting reaction on the structure of the peroxide.     

Electrochemical homolytic and heterolytic coupling of activated olefins in the absence and presence of benzyl bromide in microemulsion

Electrochemical reduction of four activated olefins namely cyclohexenone (CH), cyclopentenone (CP), methylmethacrylate (MMA), acrylonitrile (AN) in the absence and presence of benzylbromide (BBr) were investigated in CTAB/n-hexane/n-butanol/water based bicontinuous microemulsion (μE). Both cyclic voltammetric studies and galvanostatic preparative electrolysis were carried out. Cyclic voltammetric results in μE were also compared with those in N,N-dimehtylformamide (DMF) medium. Adsorption effects are observed both in DMF and μE. AN undergoes one electron reduction in aprotic solvent and two electron reduction in μE. CH, CP, BBr undergo one electron reduction and yield significant homolytic coupled products under galvanostatic conditions. AN and MMA lead to two electron reduction under identical conditions. In the presence of BBr, CH and CP alone yield significant heterolytic coupled products with simultaneous competitive resin formation. Reduction of AN leads to the formation of a identifiable quantity of propylamine and 3-phenylpropylamine in the absence and in the presence of BBr, respectively.     

山楂提取物的体外和体内抗氧化作用

采用ABTS清除2,2′-连氨-(3-乙基苯并噻唑啉-6-磺酸)二氨盐自由基、FRAP(铁离子还原/抗氧化能力测定法)和DPPH(清除二苯代苦味肼基自由基)三种体外模型筛选山楂提取物抗氧化活性;用高脂高糖乳剂建立了小鼠髙脂质模型,考察了提取物的体内抗氧化效果。山楂提取物体外ABTS、FRAP和DPPH法清除自由基能力测定结果显示,SC>SD>SB>SE>SA,SC在体内可以明显升高SOD(超氧化物歧化酶)水平(P<0.05)和降低MDA(丙二醛)水平(P<0.001)。研究结果表明,SC体外筛选抗氧化效果最好,与体内作用一致,SC体外抗氧化和体内抗脂质过氧化存在一定的相关性。     

Determination and occurrence of oxofatty acids in fats and oils

A relatively simple method is detailed for the routine isolation and estimation of oxofatty acids (OFA) in lipids. The lipid in cyclohexane is transmethylated in a two-phase, 3.5 min procedure, and the carbonyls in the methyl ester fraction are derivatized with 2,4-dinitrophenylhydrazine (DNPH) in the presence of monochloroacetic acid (MCA). The derivatives are fractionated on alumina, and the OFA fraction is obtained and evaluated spectrophotometrically. A large variety of animal, plant, and marine lipids contained OFA ranging from <1 to >50 μmoles/g. Data also show that (a) OFA are formed in naturally oxidizing fats and oils, and (b) strongly acidic conditions can cause elaboration of OFA in hydroperoxidized fats and oils.     

Comparative studies of glycolytic pathways and channeling under in vitro and in vivo modes

This study constructed cell-free glycolytic enzyme systems and compared them to their in vivo functions in Escherichia coli. Under in vitro conditions, flux regulation followed enzyme concentrations and kinetics. In E. coli, only one of the isozymes of phosphofructokinase (PfkA) and fructose-bisphosphate aldolase (FbaA) facilitate Embden-Meyerhof-Parnas (EMP) flux, but under in vitro assays, these isozymes were interchangeable. Additionally, in vitro introduction of the Entner–Doudoroff (ED) pathway improved glycolysis rates, while in vivo overexpression of the ED pathway could not capture significant flux unless its phosphotransferase system (PTS) was knocked out. Lastly, in vivo dynamic ¹³ C-experiments revealed that the labeling order of EMP pathway intermediates was not strictly cascade, indicating intracellular metabolites were not well mixed. These enigmatic observations cannot be fully explained by thermodynamics or substrate level regulations. This article supports the long-time conjecture that EMP enzymes are channeled, and the PTS may be an anchor point to initiate enzyme assemblies. © 2018 American Institute of Chemical Engineers AIChE J, 65: 483–490, 2019     

Effect of reconditioning and reuse of sucrose syrup in quality properties and retention of nutrients in osmotic dehydration of guava

The aim of this study was to assess the effect of reconditioning and reuse (RR) of sucrose syrup in quality properties and retention of nutrients in guava during osmotic dehydration (OD). Two trials of 15 OD cycles were conducted with RR of osmotic solution. The parameters of water loss (WL) and solid incorporation (SI), as well as microbial load and physical–chemical properties of syrup and fruit were evaluated. The results showed that the RR did not modify the parameters WL and SI, and the microbial load remained low. The RR did not influence the color of osmodehydrated fruit, as well as the nutrient retentions, but probably it influenced the citric acid and reduced sugar retentions. At the end, the syrup was enriched of vitamin C, polyphenols, potassium, with traces of lycopene, β-carotene, and other minerals (Fe, Mg, Mn, and Zn) and could be used to formulate new products.     

Characterization of N-acylphosphatidylethanolamine and acylphosphatidylglycerol in oats

Two polar lipid classes, both with three acyl groups, were isolated from an extract of oats and characterized by nuclear magnetic resonance spectroscopy, electrospray mass spectrometry (MS), and electron ionization MS (EIMS). Distortionless enhancement by polarization transfer (DEPT) and the two-dimensional correlation experiments 1H-detected heteronuclear multiple quantum coherence spectroscopy, heteronuclear multiple bond correlation spectroscopy, double quantum filtered correlation spectroscopy, and total correlation spectroscopy provided sufficient information for determination of the structure of the two lipid classes. The polar lipid classes were found to be N-acylphosphatidylethanolamine [1,2-diacyl-sn-glycero-3-phospho-(N-acyl)-1'-ethanolamine; N-acyl-PE] and acylphosphatidylglycerol [1,2-diacyl-sn-glycero-3-phospho-(3'-acyl)-1'-sn-glycerol]. High-performance liquid chromatography with electrospray ionization MS (HPLC-ESMS) and with electrospray ionization tandem MS (HPLC-MS/MS) were utilized for the separation and subsequent determination of molecular species. With HPLC-ESMS, ions of deprotonated molecules were obtained and with HPLC-MS/MS carboxylate ions (representing acyl groups) were obtained as well as other structurally significant ions. Fifty molecular species of N-acylphosphatidylethanolamine and 24 molecular species of acylphosphatidylglycerol were found, with a molecular mass range of 924-1032 Da and 959-1035 Da, respectively. Identification of the fatty acid isomers, as picolinyl ester derivatives, was done with gas chromatography with EIMS. Three isomers of 16:1 fatty acids were found in N-acyl-PE, and their double bond positions were determined to 6, 9, and 11 with a relative abundance of 4:10:1.     

Fractional coefficient of macromolecules in concentrated solution and in the vicinity of the critical solution temperature. Diffusion and sedimentation studies of polystyrene in toluene and trans-decalin

The concentration dependence of the frictional coefficient (f) in concentrated solutions of well-defined polystyrene fractions has been studied both in a good solvent (toluene) and in a solvent where θ conditions and condition in the vicinity of phase separation can be realized (trans-decalin). f and the self-diffusion coefficient (D⁺) have been calculated from a combination of measured translational diffusion coefficients (D) and osmotic pressure data for the systems; polystyrene $\text{(M = 390 000)}\text{trans-}\text{decalin}$ up to 90 kg/m³ at 20° (θ-conditions), 30° and 40°C; polystyrene $\text{(M = 110 000)}\text{toluene}$ up to 120 kg/m³ at 25°C. Sedimentation measurements are also reported. The main results are: (a) over a concentration interval 0–100 kg/m³, f shows more than a ten-fold and almost linear increase; (b) in trans-decalin when the temperature is raised from 20° (θ-conditions) to 40°C (good solvent conditions), keeping the concentration constant, f increases only slightly, the increase being somewhat more pronounced at higher concentrations; (c) the concentration dependence of the ratio $\text{D}\text{D}{}^{\mathrm{+}}$ is considerable under good solvent conditions but becomes gradually less pronounced when θ-conditions are approached; (d) diffusion/osmosis and velocity sedimentation give identical values of f over the entire concentration interval.