Evaluation of a modified spray-applied interfacial polymerization method for preparation of nanofiltration membranes

Nanofiltration (NF) membranes were fabricated by using piperazine (PIP) and trimesoyl chloride (TMC) by conventional and spray-applied interfacial polymerization methods, studying the effect of the application method for both phases, the number of applied layers, and the displacement speed for the spray application. A polysulfone ultrafiltration membrane was used as support. NF membranes were characterized by different spectroscopic, microscopic, and physicochemical techniques. Rejection capacity was evaluated for sodium chloride (NaCl), sodium sulfate (Na₂SO₄), and magnesium sulfate (MgSO₄) salts; the decreasing rejection order was Na₂SO₄ > MgSO₄ > NaCl for each NF membrane. NF membrane prepared with one layer of the sprayed out TMC solution and conventional application of PIP solution exhibited the highest salt rejection (99% for 1000 ppm Na₂SO₄) and a permeated flux of 10.28 L m⁻² h⁻¹ at 0.55 MPa. The modified method is a facile-reproducible preparation methodology that reduces the consumption of time, effort, and reagents leading to a scalable manufacturing process for separation technology. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48129.     

Combustion of syngas in a pressurized microturbine-like combustor: Experimental results

The different routes for power production from biomass often lead to an intermediary product such as a synthesis gas or syngas, which is typically rich in hydrogen and carbon monoxide. The simple design, fuel flexibility and size, which often matches the amount of waste energy available in industrial sites, makes microturbines an attractive solution for on-site, decentralized power generation using a limited range of alternative fuels such as synthetic gas. The properties of the synthetic fuel differ from properties of natural gas and a detailed experimental study with a separated microturbine-like pressurized combustor is therefore necessary. The present article reviews the experimental results obtained by gradually switching the fuel feed from natural gas to wet syngas in a pressurized, slightly modified lean premix microturbine combustor. Temperature profiles, pressure, emissions and flame imaging were closely monitored to detect possible problems in operability of the combustor caused by the strong difference in fuel characteristics.     

Novel route to stabilization of bioactive antioxidants by encapsulation in electrospun fibers of zein prolamine

The encapsulation of the light sensitive model β-carotene, a colorant and antioxidant molecule widely used in the food industry, has been successfully achieved in ultrafine fibers of zein prolamine, a sustainable agropolymer, by means of electrospinning. Fiber capsules were in the micro- and nanorange in the cross-section and the encapsulation preserved the fluorescence of the polyene molecules. Observations with confocal Raman imaging spectroscopy showed that the antioxidant was stable and widely dispersed inside the zein fibers but agglomerated in some areas. Nevertheless, a significant increase in the light stability of the β-carotene when exposed to UV–vis irradiation was determined for the encapsulated compound. As a result, electrospinning of zein prolamine shows an excellent outlook for its application in the stabilization of light sensitive added-value food components.     

beta-Microseminoprotein in human spermatozoa and its potential role in male fertility

beta-Microseminoprotein (MSMB) is one of the most abundant proteins in human seminal plasma. The objectives of this study were: (1) to purify MSMB from seminal plasma (SP) and generate antibodies against the pure protein; (2) to investigate the interaction of MSMB with ejaculated spermatozoa and its possible effect on the spontaneous acrosome reaction (AR); and (3) to quantify MSMB content in SP and examine its relationship with the clinical sperm parameters. MSMB was purified from SP and its presence on the sperm surface was examined by indirect immunofluorescence using a specific polyclonal antibody. The effect of MSMB on the AR was evaluated using guinea pig epididymal spermatozoa as a model. MSMB quantification assay was performed with a two-site binding ELISA using two polyclonal antibodies against MSMB. MSMB was assessed in semen samples from fertile donors (controls) and subfertile patients according to World Health Organization criteria. MSMB was detected on the sperm surface and mainly localized to the acrosomal region of the head and neck. A significant spontaneous AR inhibition was observed when guinea pig epididymal spermatozoa were preincubated with MSMB. Finally, MSMB was significantly increased in subfertile patients when compared with fertile controls (P<0.02). The association of MSMB to the sperm surface, the inhibitor effect on the spontaneous AR and the increased MSMB levels found in SP in subfertile men suggests a relationship between this protein and semen quality and a possible role in the process of fertilization.     

Lipoxygenase activity associated to fruit ripening and senescence in chayote (Sechium edule Jacq. Sw. cv. “virens levis”)

Lipoxygenase (LOX) enzyme activity and their putative isoforms were investigated during postharvest life in chayote fruit (Sechium edule Jacq. Sw. cv. “virens levis”). Possible associations of LOX with fruit quality parameters are discussed. Five LOX isoforms were identified (SeLOX‐1 to ?5) displaying different activity patterns during ripening and senescence as well as in roots, stems, and leaves. The probable role of SeLOX‐5 as a specific isoform linked to senescence was examined. The highest relative activity of LOX was registered in fruit tissue, followed by leaves, stem, and roots. Correlations were found between LOX and fruit composition variables such as the contents of linoleic (LA) and linolenic (LNA) acids, weight loss, CO₂ and ethylene production rates. LOX activity, and LA and LNA concentration decreased from Day 1 to Days 13–17, when early seed germination events became visible, indicating a transition stage between late fruit ripening and early senescence characterized by a deteriorative process.

Practical applications

Detrimental effects on fruit composition variables such as dehydration, weight loss, wilting, and sprouting symptoms, have been reported as the main causes that reduce the commercial quality and shelf life in chayote fruit and prevent their export to distant markets. To the best of our knowledge, the association of lipoxygenase (LOX) enzymes to non‐climacteric fruit ripening—like chayote—or their loss of commercial quality during prolonged shelf life has not yet been described. This is the first study that explores the role of chayote LOX activity in fruit, identifies various specific LOX isoforms associated to ripening or to the senescence process and provides new evidence that supports the hypothesis that putative LOX isoforms might be related to several postharvest detrimental effects on chayote fruit. This information could be useful to food processors or packers to pursue better profitability and consumer satisfaction.     

Access to common resources and food security: Evidence from National Surveys in Nigeria

Common resources (CRs) provide a “hidden harvest” for rural households and can also act as a safety net in the event of poor agricultural output or seasonal food gaps, hence contributing to food security. Yet only limited empirical research has assessed the relationship between CRs and the self-assessed food security conditions recorded among rural households. This exploratory paper draws on recent data from the Nigerian General Household Survey (GHS), a nationally representative sample of households administered in 2012–2013 as part of the World Bank Living Standards Measurement Study — Integrated Surveys on Agriculture (LSMS-ISA). A sustainable livelihood framework was used to contextualise CR access within the broader set of food security drivers. In Nigeria, access to common pasture and water resources is significantly associated with less reporting of food insecurity. In contrast, access to common forest tends to be associated with food insecurity, suggesting that households with access to common forest remain vulnerable (i.e. isolated from services and opportunities) despite having the advantage of the forest as a source of food. Echoing existing literature, the relative importance of these commons decreases when income of households increases. However, there are no clear signs that access to commons acts as a seasonal safety net for households during the lean season. The paper advocates streamlining CR data collection alongside agricultural data for a more integrated food security policy intervention aimed at the most vulnerable.     

A case study of pellet size fraction influence on pelletizing operation

Pellet production is constantly optimized considering different aspects of the production chain from run of mining (ROM) to metallic iron. Industrially, the trade-off between an optimum pellet-size-ratio and the maximum performance in the steel production chain is a relevant subject. The present case study at a Brazilian operation shows the impact of different pellet size fractions on performance of operation, improvements on the fired pellets, less fine generation during handling, and superior metallurgical behavior during the reduction process, resulting in the production of direct reduction iron (DRI) that add more value to the economic performance of the electric arc furnaces (EAF).     

Natural Mallow Fiber-Reinforced Epoxy Composite for Ballistic Armor Against Class III-A Ammunition

Epoxy matrix composites reinforced with up to 30 vol pct of continuous and aligned natural mallow fibers were for the first time ballistic tested as personal armor against class III-A 9 mm FMJ ammunition. The ballistic efficiency of these composites was assessed by measuring the dissipated energy and residual velocity after the bullet perforation. The results were compared to those in similar tests of aramid fabric (Kevlar?) commonly used in vests for personal protections. Visual inspection and scanning electron microscopy analysis of impact-fractured samples revealed failure mechanisms associated with fiber pullout and rupture as well as epoxy cracking. As compared to Kevlar?, the mallow fiber composite displayed practically the same ballistic efficiency. However, there is a reduction in both weight and cost, which makes the mallow fiber composites a promising material for personal ballistic protection.