Ni(ll) biosorption by Rhizopus arrhizus Env 3: the study of important parameters in biomass biosorption

BACKGROUND: The removal of toxic metals from wastewaters by biosorption, based on the metal‐binding capacities of various biological materials, has attracted much interest. However, the success of this approach depends on economic feasibility, which can be obtained by optimisation of the environmental conditions. In this study, Ni(II) biosorption experiments were carried out using a preformed biomass of Rhizopus arrhizus. A pure culture of previously isolated R. arrhizus Env 3 was used for maximum biosorption of nickel metal from nickel‐electroplating industrial effluent. RESULTS: Various environmental factors such as nickel concentration, pH, temperature, mycelial pellet weight, pretreatment of fungal biomass, dead and living fungal biomass and time course of biosorption by R. arrhizus Env 3 were optimised for maximum removal of nickel from the effluent. The maximum nickel removal rate of 618.5 mg g^?1 was observed with living biomass at pH 8, temperature 35 °C, nickel concentration 500 mg L^?1, pellet size 3 g wet weight and shaker velocity 150 rpm. Maximum nickel biosorption was obtained after 72 h. CONCLUSION: Statistical analysis of different factors such as temperature, pH, mycelial pellet size, concentration of nickel in effluent and residual nickel level showed that all these factors had significant effects on the biosorption of nickel metal by R. arrhizus Env 3 from nickel‐electroplating industrial effluent. Copyright © 2008 Society of Chemical Industry     

An IMEX predictor–corrector method for pricing options under regime-switching jump-diffusion models

An efficient second-order method for pricing European and American options under regime-switching jump-diffusion models is presented and analysed for stability and convergence. The implicit–explicit (IMEX) nature of the proposed method avoids the need to invert a full matrix and leads to tridiagonal systems that can be efficiently solved by direct methods. The IMEX predictor–corrector method is coupled with the operator splitting method to solve the linear complementarity problem of the American options. Numerical experiments are performed to demonstrate the stability and second-order convergence of the method.     

Management of natural gas resources and search for alternative renewable energy resources: A case study of Pakistan

Energy usage in Pakistan has increased rapidly in past few years due to increase in economic growth. Inadequate and inconsistent supply of energy has created pressure on the industrial and commercial sectors of Pakistan and has also affected environment. Demand has already exceeded supply and load shedding has become common phenomenon. Due to excessive consumption of energy resources it would become difficult to meet future energy demands. This necessitates proper management of existing and exploration of new energy resources. Energy resource management is highly dependent on the supply and demand pattern. This paper highlights the future demands, production and supply of energy produced from natural gas based on economic and environmental constraints in Pakistan with special emphasis on management of natural gas. An attempt has been made by proposing a suitable course of action to meet the rising gas demand. A mechanism has been proposed to evaluate Pakistan's future gas demand through quantitative analysis of base, worst and best/chosen option. CO₂ emission for all cases has also been evaluated. The potential, constraints and possible solutions to develop alternative renewable energy resources in the country have also been discussed. This work will be fruitful for the decision makers responsible for energy planning of the country. This work is not only helpful for Pakistan but is equally important to other developing countries to manage their energy resources.     

等离子渗镀CrON复合涂层结构与抗铝液熔蚀性能

采用等离子渗氮/电弧离子镀复合方法在H13模具钢表面制备出CrON涂层,研究氧流量对CrON复合涂层结构及抗铝液熔蚀性能的影响。结果表明,随着氧流量的增加,所制备的涂层主要物相由氮化物向氧化物转变,在氧流量较低时主要呈现面心立方CrN结构,而在氧流量为200 mL/min时制备的涂层形成典型的Cr₂O₃晶体相特征。掺入适量的氧,CrN涂层柱状晶生长受到抑制,涂层结构更加致密。涂层表面缺陷和粗糙度随着氧含量的增加而增大。CrON复合涂层在铝液中的失效形式是局部点蚀。由于形成致密的结构和良好的热稳定性,在氧流量为50 mL/min时制备的涂层具有优异的抗铝液熔蚀能力,而氧流量较高时表面生成致密的Cr₂O₃抗氧化层也有利于提高抗铝液熔蚀性能。     

Oesophageal perforation: a dangerous but potentially curable condition

A series of three cases of oesophageal perforation are described. All three presented differently and the X-ray findings were different in the three patients.     

Effect of Aeration on the Quality of Effluent from UASB Reactor Treating Sewage

The treatment of effluent of pilot- and full-scale upflow anaerobic sludge blanket (UASB) reactors operating at steady state was studied in an aeration-settling system. The fine pore submerged diffusers were used to aerate the effluent of UASB reactors under different operating conditions. Forty to 55% of the biochemical oxygen demand (BOD) and the chemical oxygen demand (COD) removal efficiencies were achieved by the direct aeration of the UASB effluent in the laboratory. The maximum removal efficiencies were achieved at 30?min hydraulic retention time (HRT) and a dissolved oxygen (DO) of 5–6??mg/L or high KLa (vigorous aeration). Batch experiments on nitrogen purging and the aeration of sulfides, volatile organic compounds (VOCs), and nonpurgeable organic carbons (NPOCs) were performed to ascertain the mechanism of BOD/COD removal. During aeration, BOD and COD were reduced by the stripping of H2S and VOCs and by the chemical oxidation of total sulfides and organic carbon. The stripping and chemical oxidation depended on the HRT and DO. The performance of a full-scale surface aeration system was compared to the performance of a pilot-scale diffused aeration system. Final sedimentation was effective only in removing the solids from the effluent of the aeration system. The results were confirmed by organic mass balance.     

Modification methods and applications of egg protein gel properties: A review

Egg protein (EP) has a variety of functional properties, such as gelling, foaming, and emulsifying. The gel characteristics provide a foundation for applications in the food industry and research on EP. The proteins denature and aggregate to form a dense three-dimensional gel network structure, with a process influenced by protein concentration, pH, ion type, and strength. In addition, the gelation properties of EP can be altered to varying degrees by applying different treatment conditions to EP. Currently, modification methods for proteins include physical modification (heat-induced denaturation, freeze–thaw modification, high-pressure modification, and ultrasonic modification), chemical modification (glycosylation modification, phosphorylation modification, acylation modification, ethanol modification, polyphenol modification), and biological modification (enzyme modification). Pidan, salted eggs, egg tofu, and other egg products have unique sensory properties, due to the gel properties of EP. In accessions, EP has also been used as a new ingredient in food packaging and biopharmaceuticals due to its gel properties. This review will further promote EP gel research and provide guidance for its full application in many fields.     

Microscopic characterization of petiole anatomy of Asteraceous taxa of Western Himalaya-Pakistan

Petiole anatomy of 15 species of family Asteraceae was examined which aimed to investigate petiolar anatomical structures for species level identification. Shandon Microtome was used for petiole histological preparations. Both qualitative and quantitative features were studied under microscope which showed significant variation in petiole, collenchyma, parenchyma shape/size, vascular bundles arrangement/size, and vessel elements quantity. Artemisia japonica Thunb., Cirsium vulgare (Savi) Ten., Myriactis nepalensis Less., Seriphidium brevifolium Ling & Y.R.Ling, Taraxacum officinale (L.) Weber ex F.H.Wigg., and Xanthium strumarium L. showed winged petioles. Maximum length and width of upper and lower epidermis was found in Tagetes erecta L. which is 23.05 ± 0.89 μm, 24.9 ± 1.257 μm length and 21.75 ± 1.38067 μm, 22.75 ± 0.467 μm width, respectively. Petioles of Parthenium hysterophorus L. was longest one with 9.85 ± 10.45 μm while A. japonica Thunb. showed highest number of vessel elements. Maximum size of vascular bundles was found in T. erecta L. with 5.05 ± 14.25 μm. Artemisia annua L., C. vulgare (Savi) Ten, Cyanthillium cinereum (L.) H.Rob., Helianthus annus L., M. nepalensis Less., P. hysterophorus L., Senecio chrysanthemoides DC. have trichomes while Tussilago farfara L. has highest number of vascular bundles. All species have angular collenchyma type except M. nepalensis Less., P. hysterophorus L., S. brevifolium Ling & Y.R.Ling, Tagetes minuta L., T. officinale L., S. chrysanthemoides DC., and T. farfara L. Cluster analysis implemented that distinct plant species in cluster. Petiolar anatomical structures and taxonomic key will helpful for distinguishing Asteraceous taxa at genus and species level. This taxonomic significant investigation will also provide baseline to taxonomists for other Asteraceae studies and phylogenetic research.     

High-pressure processing of fish and shellfish products: Safety,quality, and research prospects

Seafood products have been one of the main drivers behind the popularity of high-pressure processing (HPP) in the food industry owing to a high demand for fresh ready-to-eat seafood products and food safety. This review provides an overview of the advanced knowledge available on the use of HPP for production of wholesome and highly nutritive clean label fish and shellfish products. Out of 653 explored items, 65 articles published during 2016–2021 were used. Analysis of the literature showed that most of the earlier work evaluated the HPP effect on physicochemical and sensorial properties, and limited information is available on nutritional aspects. HPP has several applications in the seafood industry. Application of HPP (400–600 MPa) eliminates common seafood pathogens, such as Vibrio and Listeria spp., and slows the growth of spoilage microorganisms. Use of cold water as a pressure medium induces minimal changes in sensory and nutritional properties and helps in the development of clean label seafood products. This technology (200–350 MPa) is also useful to shuck oysters, lobsters, crabs, mussels, clams, and scallops to increase recovery of the edible meat. High-pressure helps to preserve organoleptic and functional properties for an extended time during refrigerated storage. Overall, HPP helps seafood manufacturers to maintain a balance between safety, quality, processing efficiency, and regulatory compliance. Further research is required to understand the mechanisms of pressure-induced modifications and clean label strategies to minimize these modifications.