Porphyrins and related compounds as photoactivatable insecticides. 3. Laboratory and field studies

The exposure of populations of Ceratitis capitata (fruit fly), Bactrocera oleae (olive fly) and Stomoxis calcitrans (house fly) to a bait containing mumolar concentrations of porphyrin-type photosensitizers resulted in a significant accumulation of the porphyrin by the insects and a consequent development of photosensitivity upon exposure to visible light. The photoinsecticidal activity appeared to increase with increasing hydrophobicity of the porphyrin molecule: thus, the amphiphilic dicationic meso-di(cis-4N-methyl-pyridyl)-cis-diphenyl-porphine (n-octanol/water partition coefficient = 20) was markedly more efficient than its tricationic analogue or the dianionic hematoporphyrin (n-octanol/water partition coefficient = 12). The observed large decrease in the acetylcholinesterase activity of the photosensitized flies suggests that the damage of the nervous system gives an important contribution to the phototoxic action of porphyrins. Studies with C. capitata indicate that the photoinsecticidal action of porphyrins can be utilized to control the population of noxious insects also in open field conditions.     

薯果类维生素C的分光光度法测定

为探讨分光光度测定薯果中维生素C的方法，在待测样品中加草酸处理过滤后于490nm作分光光度测定。结果表明，经分光光度扫描，生成物脎的吸收峰值为488～492nm，温度是测定过程中的重要因素。此法可用于薯果的维生素C测定，较化学方法简便。     

Coupled membrane process applied to fruit juice concentration

A coupled membrane process of membrane distillation and osmotic evaporation, where the solutions were thermostated separately at different temperatures, was developed. Enhanced water flux was obtained since the total driving force of the coupled process was higher than the sum of the driving forces of single processes. Apple, raspberry, sour cherry, red, and black currant juices were concentrated by the novel, mild technique. Presented at the 33rd International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 22–26 May 2006.     

Extraction and characterization of alkali-treated red coconut empty fruit bunch fiber

This article discusses the extraction and characterization of new natural fiber extracted from red coconut empty fruit bunch. The physicochemical, mechanical, and thermal properties of alkali-treated red coconut empty fruit bunch fibers (ARCEFBFs) were reported and compared with other natural fibers for the first time. Cellulose content (65.02 wt%), wax (0.32 wt%), density (1.421 g/cc), and tensile strength (1299.49 MPa) were identified in ARCEFBFs. Fourier transform infrared spectroscopy and X-ray diffraction analysis confirmed that ARCEFBFs are rich in cellulose content with crystallinity index of 53.6%. Thermogravimetric analysis revealed that these fibers are thermally stable until 270.48°C.     

Bromine,arsenic, cadmium,and lead in several key food groups: an assessment of relative risk

ABSTRACT

This study endeavoured to provide an overview of the bromine, Br, arsenic (As, a metalloid) and metal (cadmium, Cd, and lead, Pb) relative risk associated with the consumption of relevant food groups (lean fish, fatty fish, bivalves, cephalopods, fresh fruit, dried fruit, and green vegetables) in Portugal. Though As, Cd, and Pb have been frequently studied, a comprehensive overview applying the same state-of-the-art methodology to a wide array of foods is missing. Besides, there is a large deficit of content information and risk assessment studies on Br. Thus, it is important to apply a mathematically realistic and innovative methodology (extreme value theory) to recent and accurate databases for the aforementioned food groups and elements.

Best fits to Br, As (total), Cd, and Pb concentrations were attained through different functions, ranging from the normal distribution to the Weibull distribution. A semi-probabilistic risk assessment approach on the basis of four alternative scenarios (one monthly meal; one weekly meal; three weekly meals; one daily meal) showed low relative risk regarding Br and Pb in the selected food groups, including bivalves, which contained the highest Br and Pb contents. With respect to total As, high relative risk values were calculated for seafood, but it should be emphasized that this As is overwhelmingly organic, thus presenting low risk. For Cd, substantial relative risk associated with bivalves’ and cephalopods’ consumption, particularly with one or more weekly meal(s), was found. However, the current study enables us to compare between the relative risk of the studied food groups and scenarios, and other studies encompassing the whole diet and following long-term dietary patterns are needed for the assessment of absolute risk.     

Physical and Sensory Properties of Japanese Quince Chips Obtained by Osmotic Dehydration in Fruit Juice Concentrates and Hybrid Drying

Japanese quince has high health value, but due to its taste and texture, it is difficult to eat raw. The use of innovative drying methods to produce dried snack foods from these fruits may be of interest to producers and consumers. The physicochemical and sensory properties of 3 mm slices of Japanese quince fruit (with skin, without seeds) obtained by osmotic pre-treatment in chokeberry and apple juice concentrates, and with the use of convection (convective drying, C-D), freeze-drying (F-D), and convection-microwave-vacuum drying (hybrid) are assessed. The methods of drying osmo-dehydrated slices do not affect the dry matter content. In most dried quince, the water activity is 0.40 or lower. Pre-osmotic dehydration and drying have a significant impact on the mechanical and acoustic properties of quince chips. Sensory attractive chips emit loud acoustic emission (AE) during the breaking test. Chips that are osmo-dehydrated in a mixture of chokeberry juice concentrate and sucrose and dried by a hybrid method are attractive. They have a dark red color given by chokeberry concentrate and a slight sweet (with a slight sour-bitter) taste. The sensory evaluation was useful for determining the quality of the chips in terms of their texture (crispness) tested by mechanical methods. Their sensory ratings (overall desirability as weight of color, taste, crispness, and flavor) are high and similar (from 3.8 to 4.1). The use of innovative drying methods with pre-osmotic treatment allows obtaining dried material with properties comparable to those obtained by the F-D method, but in a much shorter time, i.e., with lower energy and using a simple method.     

Ecofriendly synthesis of silver nanoparticles using Kei-apple (Dovyalis caffra) fruit and their efficacy against cancer cells and clinical pathogenic microorganisms

Green fabrication has become a safe approach for producing nanoparticles. Plant-based biogenic synthesis of silver nanoparticles (AgNPs) has emerged as a possible alternative to traditional chemical production. In this paper, we provide a low-cost, green synthesis of AgNPs utilizing using Kei-apple (Dovyalis caffra) fruit extract. Ultraviolet–visible (UV–Vis) spectroscopy, Fourier Transform Infrared (FTIR), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Scanning-Electron Microscope (SEM), and Dynamic Light Scattering (DLS) analyses were used to characterize green produced AgNPs. The formation of AgNPs was shown to have a surface resonance peak of 415 nm in UV–visible spectra, and FTIR spectra verified the participation of biological molecules in Synthesis of AgNPs. The TEM revealed that the biosynthesized AgNPs were mostly spherical in form, with size range of 12–53 nm. XRD diffractogram was used to demonstrate the face cubic centre (fcc) character of AgNPs. Excellent anticancer activity of AgNPs was recorded where more than 80% of Prostate Cancer (PC-3) cell lines was inhibited by 100–150 µg/mL of AgNPs, while 38% only was recorded using AgNO₃ and 55.62% was recorded D. caffra fruit extract at 150 µg/mL. Destructions of PC-3 cell was observed as a result of exposed to AgNPs, followed by D. caffra fruit extract, while minor alterations were recorded as exposed to AgNO₃. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging using AgNPs was three fold using fruit extract at 100 µg/mL indicating good antioxidant activity. Excellent inhibitory activity of AgNPs was recorded against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus fumigatus with inhibition diameter zone 28.22 ± 0.25 mm, 23.21 ± 0.35 mm, 27.25 ± 0.03 mm, 28.40 ± 0.15 mm, 29.23 ± 0.44 mm, and 9.52 ± 0.5 mm, respectively compared with AgNO₃. D. caffra fruits considered a promising and safe source for fabrication of AgNPs with multi-biological functions.     

Ultrasound-assisted nanofluid flooding to enhance heavy oil recovery in a simulated porous media

Herein thermally treated empty fruit bunch SiO₂ nanoparticles (EFBSNP) was produced by ultrasound-assisted wet-milling and their effectiveness in enhancing cavitation effect of ultrasound to improve heavy oil recovery was evaluated. Empty fruit bunch ash (EFBA) was thermally treated to enhance its SiO₂ content. Surface properties and size distribution of EFBSNP were studied using transmission electron microscopy and dynamic light scattering. X-ray diffractometer identified the crystal phase, the active group was ascertain using Fourier-transform infrared spectroscopy and thermal stability was established by differential scanning calorimetry. Moreover, the surface chemical composition was determined by X-ray photoelectron spectroscopy. The ability of empty fruit bunch SiO₂ nanofluid (EFBSNF) to absorb ultrasound in heavy oil and the impact of ultrasound assisted EFBSNF flooding to enhance oil recovery of heavy oil was assessed. The microstructure analysis revealed EFBSNP of size ranges 17.78–115.38 nm with a purity of 94%. EFBSNF assisted ultrasound decreased interfacial tension to 0.2 mN/m, thus mobilizing the trapped oil droplet in the pores effectively. Ultrasound assisted EFBSNF flooding increased oil recovery by 44.33% compared to 26.33% without ultrasound.     

基于混合果蝇优化算法的选址-库存-配送集成优化研究

本文面向企业运营管理实践,构建了一种基于联合补货策略的选址-库存-配送集成优化新模型。作为典型的NP-hard问题,传统算法难以高效稳定地求解,故本文设计了一种新的混合果蝇优化算法(Fruit Fly Optimization Algorithm, FOA),通过引入进化算法的信息交换、变异、选择操作来增强算法局部寻优能力,采取概率性飞行策略来平衡算法的全局寻优与局部寻优。算例结果表明,新混合FOA算法的准确性和稳定性较标准FOA有了明显的改善,与差分进化、自适应混合差分进化、粒子群优化相比也具有比较优势。     

果树干周生长模型的研究

生长模型是定量研究果树干周生长过程的有效手段.果树干周生长规律常用L og istic方程、M itscherlich方程、三参数和四参数的R ichards方程、三角函数方程来模拟.本文首次用拟W e ibu ll方程模拟果树干周的生长规律,结果表明,W e ibu ll方程达到了与果树干周最佳拟合的效果,同时,本文方法可先给定由实际情况(如立地条件等)所确定的干周生长的最大值,这使得在研究中可以更好地预测果树将来的干周增长.另外,考虑到因实际情况所造成的初始干周不同这种普遍现象及其引起的生长过程的差异,本文直接引入与单株树体有关的基准干周作为参数,建立了与实际生长情况相结合的干周生长模型,获得了满意的结果.