CONJUGATE HEAT AND MASS TRANSFER IN CONVECTIVE DRYING OF MULTIPARTICLE SYSTEMS PART II: SOYBEAN DRYING

Abstract

This is the second of two papers concerning conjugate transport in convective drying of multiparticle systems. In the first paper (part 1), a solution methodology for conjugate transport problems was porposed and successfully tested for assemblages of spheres. This paper deals with the application of the proposed methodology to a soybean drying problem. The analysis in this study allowed certain phenomena, that are usually not present in single-kernel and deep-bed drying analyses, to be captured by the drying rate curves. The results presented here reinforce the need to take into account particle interactions when studying the drying mechanisms of multiparticle systems.     

Evaluation of Compacted Cementitious Composites for Porous Bearings

The use of porous materials as a restrictor in aerostatic bearings provides many advantages over conventional restrictors, such as small variation of temperature, high damping, high operational speeds, limited wear, and capacity to support radial, axial, and combined loading. A design of experiment (DOE) was carried out to evaluate cold‐pressed cementitious composites as an air restrictor in thrust bearings. The physical and mechanical properties such as the apparent porosity, permeability, and elastic modulus were investigated in this work, thus verifying the structural and flow characteristics of the composites for such application. The composites fabricated with low compacting pressure and small silica particles provided the material requirements for porous bearings.     

Recovery of carbon dioxide from sugarcane fermentation broth in the ethanol industry

Ethanol is one alternative to the use of petroleum-based fuels. It is produced on a large scale in Brazil from sugarcane to the magnitude of billions of liters per year. During the ethanol production step, a considerable amount of byproducts is obtained and treated as waste. Carbon dioxide is one of these byproducts and a substance of interest especially for food industries. Because the production of 1000 kg of ethanol generates approximately 950 kg of CO₂, this work intends to analyze a cryogenic distillation process for the production of CO₂ by means of computational simulations. The results obtained were in agreement with real operational conditions, achieving CO₂ concentrations up to 100% (v/v). With an initial CO₂ concentration of 95% (v/v), 7 separation stages were obtained, achieving the limit of 5 stages for higher CO₂ concentrations in the raw gas. The effect of initial CO₂ concentrations on the final product and the concentration profiles along the column are also presented. In order to optimize the process, it was observed that, for a maximum feed flow of 3333 kg/h (CO₂ concentration of 99%), the plant was able to obtain 10.48 kgCO₂/kW, recovering about 2828 kgCO₂/h at a final product concentration of 99.90% (v/v) at ?25 °C.     

Anticoagulant, Antioxidant and Antitumor Activities of Heterofucans from the Seaweed Dictyopteris delicatula

In the present study, six families of sulfated polysaccharides were obtained from seaweed Dictyopteris delicatula by proteolytic digestion, followed by acetone fractionation and molecular sieving on Sephadex G-100. Chemical analyses demonstrated that all polysaccharides contain heterofucans composed mainly of fucose, xylose, glucose, galactose, uronic acid, and sulfate. The fucans F0.5v and F0.7v at 1.0 mg/mL showed high ferric chelating activity (～45%), whereas fucans F1.3v (0.5 mg/mL) showed considerable reducing power, about 53.2% of the activity of vitamin C. The fucan F1.5v presented the most prominent anticoagulant activity. The best antiproliferative activity was found with fucans F1.3v and F0.7v. However, F1.3v activity was much higher than F0.7v inhibiting almost 100% of HeLa cell proliferation. These fucans have been selected for further studies on structural characterization as well as in vivo experiments, which are already in progress.     

A Perinatal Palatable High-Fat Diet Increases Food Intake and Promotes Hypercholesterolemia in Adult Rats

The main goal of the present study was to evaluate the long-term effects of a perinatal palatable high-fat diet on the food intake and cholesterol profile of adult rats. Male Wistar rats (aged 22 days) were divided into two groups according to their mother’s diet during gestation and lactation (C _p, n = 10; pups from control mothers; and HL_p n = 10; pups from mothers fed a palatable high-fat diet). At the 76th day, pups were housed individually for 14 days, and daily food consumption was determined during a period of 6 days. Blood from 100-day-old rats was sampled by cardiac puncture. Fasting (12 h) serum glucose, total cholesterol, LDL-C, HDL-C, triglycerides (TG), and VLDL-C levels were determined. The measurement of food intake was higher in the animals submitted to a hyperlipidic diet during the perinatal period. Serum total cholesterol, LDL-C, HDL-C, TG, VLDL-C and glycemia were increased in the HL_p group compared to the control group. Our findings show that an early life environment with a high-fat diet can contribute to metabolic disease in later life.     

Prediction and comparison of textural properties of magnetic copolymer supports for enzyme immobilization

Magnetic polymers supports have proven to be valuable materials for enzyme immobilization, as they allow recovering the catalyst by magnetic separation, precluding the need for costly and time-consuming separation steps. In this study, magnetic copolymer supports were synthesized using styrene (STY) and different crosslinking agents (divinylbenzene, ethylene glycol dimethacrylate, or triethylene glycol dimethacrylate) and initiators (azobisisobutyronitrile or benzoyl peroxide) and used to immobilize Candida antarctica lipase B (CALB). The aim was to obtain biocatalysts with high enzymatic activity and satisfactory morphological properties for use in biotransformation reactions. Two morphological properties known to influence the immobilization yield were taken into consideration, specific surface area, and swelling index. Experimental data were compared to the predictions of a model based on molar balance, method of moments, numerical fractionation, and elementary gel structures. The high correlation (R² = 0.9974) between experimental and predicted values demonstrated the suitability of the model for estimating the textural properties of enzyme supports. CALB was successfully immobilized, showing high hydrolytic activity (500–700 U g⁻¹) and good thermal stability at 50°C. CALB/STY-EGDMA-M was 14 times more stable than free CALB. The results confirm the efficiency of the immobilization method and the suitability of the copolymers for enzyme immobilization.     

Synthesis of Isopropyl Palmitate by Lipase Immobilized on a Magnetized Polymer Matrix

Penicillium camemberti lipase immobilized on a magnetized poly(styrene-co-divinylbenzene) was used as a biocatalyst for isopropyl palmitate synthesis. The reaction conditions were determined by 2² factorial central composite design. A mathematical model based on a simplified kinetic approach was developed to describe the system and validated with the experimental data. An assay carried out in a stirred-tank reactor confirmed the proposed model. The ester was purified and the properties such as density and water content were similar to those found in commercially available isopropyl palmitate.     

A Synthetic MUC1 Glycopeptide Bearing βGalNAc‐Thr as a Tn Antigen Isomer Induces the Production of Antibodies against Tumor Cells

This study presents the synthesis of the novel protected O‐glycosylated amino acid derivatives 1 and 2 , containing βGalNAc‐SerOBn and βGalNAc‐ThrOBn units, respectively, as mimetics of the natural Tn antigen (αGalNAc‐Ser/Thr), along with the solid‐phase assembly of the glycopeptides NHAcSer‐Ala‐Pro‐Asp‐Thr[αGalNAc]‐Arg‐Pro‐Ala‐Pro‐Gly‐BSA ( 3 ‐BSA) and NHAcSer‐Ala‐Pro‐Asp‐Thr[βGalNAc]‐Arg‐Pro‐Ala‐Pro‐Gly‐BSA ( 4 ‐BSA), bearing αGalNAc‐Thr or βGalNAc‐Thr units, respectively, as mimetics of MUC1 tumor mucin glycoproteins. According to ELISA tests, immunizations of mice with βGalNAc‐glycopeptide 4 ‐BSA induced higher sera titers (1:320 000) than immunizations with αGalNAc‐glycopeptide 3 ‐BSA (1:40 000). Likewise, flow cytometry assays showed higher capacity of the obtained anti‐glycopeptide 4 ‐BSA antibodies to recognize MCF‐7 tumor cells. Cross‐recognition between immunopurified anti‐βGalNAc antibodies and αGalNAc‐glycopeptide and vice versa was also verified. Lastly, molecular dynamics simulations and surface plasmon resonance (SPR) showed that βGalNAc‐glycopeptide 4 can interact with a model antitumor monoclonal antibody (SM3). Taken together, these data highlight the improved immunogenicity of the unnatural glycopeptide 4 ‐BSA, bearing βGalNAc‐Thr as Tn antigen isomer.     

Lipid oxidation inhibitory effects and phenolic composition of aqueous extracts from medicinal plants of colombian amazonia

Diverse plants of ethnobotanic interest in Amazonia are commonly used in traditional medicine. We determined the antioxidant potential against lipid peroxidation, the antimicrobial activity, and the polyphenol composition of several Amazonian plants (Brownea rosademonte, Piper glandulosissimum, Piper krukoffii, Piper putumayoense, Solanum grandiflorum, and Vismia baccifera). Extracts from the plant leaf, bark, and stem were prepared as aqueous infusions, as used in folk medicine, and added to rat liver microsomes exposed to iron. The polyphenolic composition was detected by reverse-phase HPLC coupled to diode-array detector and MS/MS analysis. The antimicrobial activity was tested by the spot-on-a-lawn method against several indicator microorganisms. All the extracts inhibited lipid oxidation, except the P. glandulosissimum stem. The plant extracts exhibiting high antioxidant potential (V. baccifera and B. rosademonte) contained high levels of flavanols (particularly, catechin and epicatechin). By contrast, S. grandiflorum leaf, which exhibited very low antioxidant activity, was rich in hydroxycinnamic acids. None of the extracts showed antimicrobial activity. This study demonstrates for the first time the presence of bioactive polyphenolic compounds in several Amazonian plants, and highlights the importance of flavanols as major phenolic contributors to antioxidant activity.