Effect of harvesting hour on some physical and mechanical properties of Rosa damascena Mill

BACKGROUND: Mechanization of Rosa damascena flower harvest is limited because of the asynchronous flowering period, the necessity for the harvest operation to take place in the early hour of the morning, and a lack of knowledge regarding the physical–mechanical properties of R. damascena. This study investigated the effect of harvesting hour on some physical–mechanical properties of R. damascena. RESULTS: The terminal velocity of the rose flower ranged from 4.00 to 2.38 m s^?1. The highest picking force was found to be 6.29 N for the harvesting hour of 06:00 am. Tear forces of petal changed from 1.54 to 0.97 N for the harvesting hour of 06:00 am and 12:00 pm, respectively. The tension force of pedicel varied between 8.25 and 7.76 N. The weight of the rose flower was measured as an average of 1.61 and 1.50 g at 06:00 am and 12:00 pm, respectively. Horizontal and vertical projection areas of rose flowers were positively correlated with harvesting hour, with an R² of 0.97 and 0.75, respectively. Results showed that there was a minor loss in colour for both inner and outer surfaces of petals. CONCLUSION: The results of physical–mechanical properties of R. damascena obtained from this study should be considered for the operation of flower harvest mechanization. Copyright © 2011 Society of Chemical Industry     

The effect of using an exopolysaccharide‐producing culture on the physicochemical properties of low‐fat and reduced‐fat Kasar cheeses

A mixed starter culture containing exopolysaccharide (EPS)‐producing strains of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was combined with Lactobacillus helveticus LH301 and used in the manufacture of low‐fat and reduced‐fat Kasar cheeses. For comparison, low‐fat (C10) and reduced‐fat (C20) cheeses were made using EPS‐producing (EPS⁺) starter strain and EPS‐non‐producing (EPS^?) starter strain. The physicochemical properties of the cheeses were assessed in terms of chemical composition, texture, microstructure and microbial content over 90 days. Cheeses made with EPS‐producing culture (EPS10 and EPS20) had lower protein contents than control cheeses with 10% and 20% fat in dry basis (C10 and C20). Scanning electron microscopy images showed that using EPS‐producing culture resulted in a less compact protein matrix and sponge‐like structure in the cheese samples. In general, cheeses made using EPS‐producing culture had lower total viable counts. This could be related to the reduced survivability of EPS‐producing cells in the cheese matrix during ripening due to autolysis ability.     

Compositional,biochemical and textural changes during ripening of Tulum cheese made with different coagulants

In the present study, biochemical, chemical and texture changes in Tulum cheeses made using calf rennet and microbial rennets (Aspergillus niger protease and Rhizomucor miehei protease) were compared during ripening for up to 90 days. A total of 15 free fatty acids (FFAs) were detected in the cheese samples. The peroxide values (PV) of the cheeses increased significantly (P < 0.05) during ripening and the cheese made with calf rennet had the highest PV. Proteolysis in the cheeses increased as the ripening time increased. α_s1‐casein and β‐casein degradation was higher in cheeses manufactured with R. miehei protease. Cheeses made with calf rennet were significantly (P < 0.05) harder, more adhesive, more cohesive and more resilient than those made with microbial rennet.     

Phenolic composition,enzyme inhibitory,and antioxidant activity of <Emphasis Type="Italic">Bituminaria bituminosa</Emphasis>

This study aimed to evaluate the in vitro antioxidant and enzyme inhibitory activities of ethyl acetate, methanol, and water extracts of Bituminaria bituminosa. In phosphomolybdenum assay, the methanol extract showed the highest activity (166.78 μmol TEs/g dry plant). The water extract exhibited the highest scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH^?) and 2,2-azino-bis (3-ethylbenzothiazloine-6-sulphonic acid) (ABTS^?+). In addition, it exhibited the highest activity in cupric ion reducing (CUPRAC) and ferric reducing antioxidant power (FRAP) assays (41.26 and 46.82 μmol TEs/g dry plant). The extracts did not show cholinesterase and tyrosinase inhibitory activity. However, α-glucosidase inhibition assay resulted in the superiority of water extract (1233.86 μmol ACEs/g dry plant). In the case of α-amylase inhibitory assay, the ethyl acetate extract showed the highest activity (53.65 μmol ACEs/g dry plant). The water extract exhibited the highest phenolic content (31.70 μmol GAEs/g dry plant). In contrast, the methanol extract was found rich in flavonoid compounds (5.29 μmol REs/g dry plant). The water extract contained considerable amounts of rosmarinic acid, luteolin, quercetin, and rutin. Therefore, it can be used as a source of new and alternative antioxidant and enzyme inhibitory agents.     

A Novel Sprague-Dawley Rat Model Presents Improved NASH/NAFLD Symptoms with PEG Coated Vitexin Liposomes

Chronic liver disease (CLD) is a global threat to the human population, with manifestations resulting from alcohol-related liver disease (ALD) and non-alcohol fatty liver disease (NAFLD). NAFLD, if not treated, may progress to non-alcoholic steatohepatitis (NASH). Furthermore, inflammation leads to liver fibrosis, cirrhosis, and hepatocellular carcinoma. Vitexin, a natural flavonoid, has been recently reported for inhibiting NAFLD. It is a lipogenesis inhibitor and activates lipolysis and fatty acid oxidation. In addition, owing to its antioxidant properties, it appeared as a hepatoprotective candidate. However, it exhibits low bioavailability and low efficacy due to its hydrophobic nature. A novel rat model for liver cirrhosis was developed by CCL4/Urethane co-administration. Vitexin encapsulated liposomes were synthesized by the ‘thin-film hydration’ method. Polyethylene glycol (PEG) was coated on liposomes to enhance stability and stealth effect. The diseased rats were then treated with vitexin and PEGylated vitexin liposomes, administered intravenously and orally. Results ascertained the liposomal encapsulation of vitexin and subsequent PEG coating to be a substantial strategy for treating liver cirrhosis through oral drug delivery.     

Polymerization of epoxides catalyzed by a mixed‐valent iron trifluoroacetate [Fe3O(O2CCF3)6(H2O)3]

The readily available mixed‐valent iron trifluoroacetate complex [Fe₂^IIIFe^II(µ₃‐O)(O₂CCF₃)₆(H₂O)₃] is an effective catalyst for the polymerization of epoxides. A very small amount of the catalyst (1.0–0.01 mol%) could initiate the polymerization of cyclohexene oxide, cyclopentene oxide and epichlorohydrin. Based on quantitative end‐group analysis by ¹⁹F NMR spectroscopy, a Lewis acid (LA^⊕) catalyzed anionic reaction mechanism is proposed. Copyright © 2012 Society of Chemical Industry     

Direct pyrolysis mass spectrometry analysis of fresh and aged $\hbox{PF}_{6}^{-}$‐doped polythiophenes

In this study, pyrolysis mass spectrometry has been applied for the investigation of thermal characteristics of ‐doped polythiophene (PTh) films. Thermal degradation of PTh showed behaviour identical with ‐doped polythiophene (BF₄‐PTh), indicating that the effects of the dopants in question on the thermal characteristics of the PTh are not significant. Besides the oligomer peaks (up to hexamer), peaks indicating decomposition of the thiophene ring have also been detected as in the case of BF₄‐PTh. However, the data also indicated that the oxidation of the dopant was much more effective, yielding mainly POF₃, H₃PO₄ compounds even for the freshly prepared samples. Upon ageing, the yield of these products increased and exposure to air for more than 50 days also caused degradation of the PTh chains. Furthermore, substitution of the thiophene (Th) ring by fluorine has been recorded and was associated with reactions of Th with the reactive oxidation products of the dopant. Analyses of the de‐doped samples showed that although de‐doping was effective to a certain extent, inward diffusion of the counter ion (C₄H₉)₄N⁺ has also occurred. This diffusion was more efficient than that was observed for BF₄‐PTh samples. Copyright © 2004 Society of Chemical Industry     

Essential work of fracture of poly(ϵ‐caprolactone)/boehmite alumina nanocomposites: Effect of surface coating

The essential work of fracture (EWF) approach was adopted to reveal the effect of nanofillers on the toughness of poly (?‐caprolactone) (PCL)/boehmite alumina (BA) nanocomposites. Synthetic BA particles with different surface treatments were dispersed into the PCL matrix by extrusion melt compounding. The morphology of the composites was studied by scanning electron microscopy. Differential scanning calorimetry and wide‐angle X‐ray scattering were used to detect changes in the crystalline structure of PCL. Also, mode I type EWF tests, dynamic mechanical analysis, and quasi‐static tensile tests were applied to study the effect of the BA nanofillers on the mechanical properties of the nanocomposites. BA was homogeneously dispersed and acted as heterogeneous crystallization nucleant and a nonreinforcing filler in PCL. The tensile modulus and yield strength slightly increased and the yield strain decreased with increasing BA content (up to 10 wt %). The effect of the BA surface treatment with octylsilane was negligible by contrast to that with alkylbenzene sulfonic acid (OS2). Like the tensile mechanical data, the essential and nonessential work of fracture parameters did not change significantly either. The improved PCL/BA adhesion in case of OS2 treatment excluded the usual EWF treatise. This was circumvented by energy partitioning between yielding and necking. The yielding‐related EWF decreased, whereas the nonessential EWF increased with BA content and with better interfacial adhesion. This was attributed to the effect of matrix/filler debonding. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

An upgraded artificial bee colony (ABC) algorithm for constrained optimization problems

Artificial bee colony (ABC) algorithm developed by Karaboga is a nature inspired metaheuristic based on honey bee foraging behavior. It was successfully applied to continuous unconstrained optimization problems and later it was extended to constrained design problems as well. This paper introduces an upgraded artificial bee colony (UABC) algorithm for constrained optimization problems. Our UABC algorithm enhances fine-tuning characteristics of the modification rate parameter and employs modified scout bee phase of the ABC algorithm. This upgraded algorithm has been implemented and tested on standard engineering benchmark problems and the performance was compared to the performance of the latest Akay and Karaboga’s ABC algorithm. Our numerical results show that the proposed UABC algorithm produces better or equal best and average solutions in less evaluations in all cases.     

Increasing the conversion fraction of sulfur to sodium thiosulfate with the ultrasound energy

The usage of ultrasound has gained popularity in the recent years. Ultrasonic processing means blasting liquids, usually water, with very intense sound at high frequency, producing very well mixed powerful chemical and physical reactions. This paper deals with the investigation of the effect of ultrasonic energy on the conversion fraction of sulfur in the production reaction of sodium thiosulfate which was obtained from sulfur and Na₂SO₃ solution. Concentration of Na₂SO₃ solution parameter was chosen as the constant parameter. The experiments were performed with various amplitudes of ultrasound power and in the absence and presence of ultrasound energy in various temperatures with various particle sizes. The results indicate that the conversion fraction values increase in the presence of ultrasound energy and increase at high amplitude values.