Applications of chitosan in food,pharmaceuticals, medicine,cosmetics, agriculture,textiles, pulp and paper,biotechnology, and environmental chemistry

Environmental Chemistry Letters - Chitosan is a biopolymer obtained from chitin, one of the most abundant and renewable materials on Earth. Chitin is a primary component of cell walls in fungi, the...     

Seaweed for climate mitigation,wastewater treatment,bioenergy, bioplastic,biochar, food,pharmaceuticals, and cosmetics: a review

The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.

     

Marine reserve design: optimal size, habitats, species affinities, diversity, and ocean microclimate.

The design of marine reserves is complex and fraught with uncertainty. However, protection of critical habitat is of paramount importance for reserve design. We present a case study as an example of a reserve design based on fine-scale habitats, the affinities of exploited species to these habitats, adult mobility, and the physical forcing affecting the dynamics of the habitats. These factors and their interaction are integrated in an algorithm that determines the optimal size and location of a marine reserve for a set of 20 exploited species within five different habitats inside a large kelp forest in southern California. The result is a reserve that encompasses approximately 42% of the kelp forest. Our approach differs fundamentally from many other marine reserve siting methods in which goals of area, diversity, or biomass are targeted a priori. Rather, our method was developed to determine how large a reserve must be within a specific area to protect a self-sustaining assemblage of exploited species. The algorithm is applicable across different ecosystems, spatial scales, and for any number of species. The result is a reserve in which habitat value is optimized for a predetermined set of exploited species against the area left open to exploitation. The importance of fine-scale habitat definitions for the exploited species off La Jolla is exemplified by the spatial pattern of habitats and the stability of these habitats within the kelp forest, both of which appear to be determined by ocean microclimate.     

Beijing's coordinated development of population,resources, environment,and economy

Since the Olympic Games will be held in Beijing at 2008, the urban development plan of Beijing deserves special attention. The essence of regional sustainable development is that population (P), resources (R), environment (E) and economy (E) could develop with sustenance, order and coordination during a certain period, which forms a complex system called the PREE complex system. For this system, a multi-objective integrated model is formulated and solved by a nonlinear goal programming technique. Beijing's PREE complex system is then used as an empirical study. Twelve interesting goals are carefully selected, the parameters of each goal function were estimated by using Beijing's 50-year (1949–1999) statistical data, and their ideal goal limits for 2000 and 2005 are chosen according to the 9th and 10th Five-Year Economic Development Plans of Beijing. The results showed that population size is the most sensitive element in Beijing's PREE complex system. Furthermore, some suggestions related to public policies about the urban development of Beijing are proposed.     

Carbon nitride,metal nitrides,phosphides, chalcogenides,perovskites and carbides nanophotocatalysts for environmental applications

Environmental Chemistry Letters - Effective technologies and materials are needed for environmental detoxification and clean energy production. The actual photocatalytic technology is largely...     

Fractionation of Mn, Fe, Zn and Cu in Sediments of Khor Kalabsha, Lake Nasser, Egypt

Khor Kalabsha is the second largest Khor in Lake Nasser, which is a freshwater side-branch of the main lake. Chemical analysis of the samples indicates that calcium carbonate and organic matter content in the surface sediments average 17.8 and 3.07%, respectively. Moreover, manganese, iron, zinc and copper concentrations are lower in Khor Kalabsha than in other lakes of Egypt. It has been found that both oxides and residual forms constitute the major part of the measured elements in the study area, while manganese and iron play an important role in building up clay minerals. It is noted that both zinc and copper fractions are controlled by biological and biochemical processes.     

Nanoregulation along the product life cycle in the EU,Switzerland, Thailand,the USA,and intergovernmental organisations,and its compatibility with WTO law

Abstract

Due to vast research programmes of industrial countries during the last two decades, our knowledge about the intrinsic properties of nanomaterials has increased considerably. However, ‘nanoregulation’ lags behind this progress. Key elements of nanoregulation are definition/scope and safety/consumer information. Safety information along the nano life-cycle is vital for the nanoparticle producer down to the industrial downstream user (product producer). However, nanodeclaration (in the sense of a label on the product for consumers) is not yet widely spread, in different geographic regions for different reasons. This is a case study for the EU, Switzerland, Thailand, the USA, and Intergovernmental Organisations. In addition, this study investigates inter- and governmental activities and the relationship between nanodeclaration and WTO rules. Non-compliance with WTO rules is a pretext for not introducing nanodeclaration in products. It is concluded that WTO rules do not exclude nanodeclaration.     

Energy,population, and agricultural productivity in Iran

Solar energy feeds all life on this planet's surface. The energy of the Sun can be tapped and converted to the different forms of energy by renewable energy systems, such as solar power plants, photovoltaic systems, and plants. Land is needed for food production, which is the most globally important activity. With increasing population, the required area is determined by consumption and production patterns. The world is globally divided into poor and rich areas of production and consumption, which have large differences. Iran's energy and food production and consumption are studied and compare with poor and rich examples. It is concluded that available agricultural land is limited and currently declining per capita due to population growth. The expansion of irrigated crop area, high-quality seed, and modern farming techniques can marginally improve agricultural productivity and provide relative self-sufficiency in grain production. Much of the growth in Iran's renewable energy is attributed to hydroelectricity power plants. Solar energy, wind, hydro and geothermal energy are also potential forms of sustainable energy in Iran.     

Aspects of a zooplankton,phytoplankton, phosphorus system

In this paper a three-dimensional dynamical system which models the three-species system made up of phytoplankton, zooplankton and organic phosphorus nutrient in a lake environment is studied. The system is part of a more general limnological model for eutrophic lakes and impoundments which has been developed by Battelle Northwest Laboratories. It is shown that this system, henceforth referred to as Z-P-P, has a phase portrait comprised of a plane portrait embedded in the three-dimensional space R³ as an “attractor”.¹ Under a small perturbation of the nutrient equation it is shown that the system is essentially a classical Volterra-Lotka system embedded in a three-dimensional phase space R³.The system derived from Z-P-P by the addition of a term to the nutrient equation which represents the organic phosphorus contribution of dying phytoplankton is also considered. The equilibria of this system are studied and what can be deduced of the phase portrait is compared with that of the above systems. It is found that these phase portraits are qualitatively indifferent to the form of the growth rate functions for zooplankton and phytoplankton provided they are monotone increasing. Some discussion about the stability of these systems is included. Throughout this paper results are interpreted in limnological terms.     

Concentrations of cadmium,manganese, copper,zinc, and lead in the tissues of the oyster (Crassostrea iredalei) obtained from Setiu Lagoon,Terengganu, Malaysia

Heavy metals pollution in aquatic environments is a major problem contributing to human health issues. The study of these pollutants through bioindicators such as the oyster Crassostrea iredalei is important for (1) determining the levels and sources and (2) regulating the quantity of pollutants. The concentrations of cadmium (Cd), manganese (Mn), copper (Cu), zinc (Zn), and lead (Pb) in tissues of C. iredalei, sediment and surrounding water was measured, and data was analyzed to determine the relationship between sampling periods and between oyster tissue, sediment, and water. The highest concentration of metals in oyster tissue was Zn, followed by Cu, Mn, Cd, and Pb. Concentrations of Cd, Cu, and Zn exceeded the maximum level allowed according to the Malaysian Food Act of 1983, which is equivalent to the WHO recommended levels of heavy metals in organisms used for consumption. The highest metal concentration in sediment was Mn followed by Zn, Pb, Cu, and Cd. Concentrations of heavy metals in surrounding water were Zn, Pb, Cu, Mn, and Cd. There was no correlation between metal concentration in oyster tissue and in sediment for all five metals.     

On Advocacy by Environmental Scientists: What, Whether, Why, and How

Abstract:  Debate about the nature and appropriateness of advocacy by environmental scientists is important—it represents understanding the role of these citizens in our society. Much has been written about advocacy by scientists, and that literature describes substantial diversity in reasons why advocacy by scientists is or is not appropriate. Despite the nature of this literature there has been no comprehensive, systematic review of why some favor and others oppose advocacy by environmental scientists. Through a literature review we catalogued, categorized, and critiqued the arguments used for and against the appropriateness of advocacy by environmental scientists. Most arguments, whether for or against advocacy, are characterized by some significant deficiency. From our analysis of the literature an argument emerges that to date has never been fully articulated: that advocacy is nearly unavoidable, and that scientists, by virtue of being citizens first and scientists second, have a responsibility to advocate to the best of their abilities, to improve their advocacy abilities, and to advocate in a justified and transparent manner. We also discuss the meaning and relevance of advocacy being justified and transparent. We suggest scientists expend their efforts to better understand what constitutes appropriate advocacy and spend less effort pondering whether they should advocate .     

Climatic Change, Wildfire, and Conservation

Abstract:  Climatic variability is a dominant factor affecting large wildfires in the western United States, an observation supported by palaeoecological data on charcoal in lake sediments and reconstructions from fire-scarred trees. Although current fire management focuses on fuel reductions to bring fuel loadings back to their historical ranges, at the regional scale extreme fire weather is still the dominant influence on area burned and fire severity. Current forecasting tools are limited to short-term predictions of fire weather, but increased understanding of large-scale oceanic and atmospheric patterns in the Pacific Ocean (e.g., El Niño Southern Oscillation, Pacific Decadal Oscillation) may improve our ability to predict climatic variability at seasonal to annual leads. Associations between these quasi-periodic patterns and fire occurrence, though evident in some regions, have been difficult to establish in others. Increased temperature in the future will likely extend fire seasons throughout the western United States, with more fires occurring earlier and later than is currently typical, and will increase the total area burned in some regions. If climatic change increases the amplitude and duration of extreme fire weather, we can expect significant changes in the distribution and abundance of dominant plant species in some ecosystems, which would thus affect habitat of some sensitive plant and animal species. Some species that are sensitive to fire may decline, whereas the distribution and abundance of species favored by fire may be enhanced. The effects of climatic change will partially depend on the extent to which resource management modifies vegetation structure and fuels.     

Metal passivity as mechanism of metal carcinogenesis: Chromium,nickel, iron,copper, cobalt,platinum, molybdenum

For the transition metals chromium, nickel, iron, copper, cobalt, platinum, and molybdenum, mechanisms of stable bonding in biochemistry (emphasis on carcinogenic mechanisms), chemistry, industrial chemistry, as well as epidemiological, occupational, orthopedic (implant devices) effects related to carcinogenesis, were reviewed. Hypothetically, the propensity to stable bonding (inertness), which ensures the metals’ performance capacity for consumers and industrial application, relates to their carcinogenicity. For chromium, a relationship between industrial/chemical and biological reactivity was noted for the tendency of Cr(III) ions to cause hydrolysis previous to stable bonding, as occurs during anodic passivation, leather tanning, and as indicated in biochemical studies pertaining to a mechanism of DNA condensation, which was suggested as a carcinogenic mechanism. The involvement of metal hydrolysis in both anodic passivation and biochemistry was noted also for nickel, iron, and platinum; the DNA interaction of platinum (cis-platin) is known to depend on hydrolysis. For nickel, issues of potential (V) were found important in both passivation and carcinogenicity. Comparably, the passivity behavior of cobalt and copper was found atypical, and their carcinogenicity yet unclear. Molybdenum, contained in passivated metallic implants, may relate to implant-associated carcinogenesis. Occupational carcinogenic effects were indicated for chromium, nickel, iron, and cobalt as caused by both reactive and passivated metal species. Exposure to acids and chronic respiratory irritation/infection/inflammation in workers were important cofactors in metal carcinogenesis. For wood and leather workers exposed to dust, the assumed presence in dust of metal particles abraded from alloys (sawing or cutting blades) may be a carcinogenic exposure hazard.     

广东省南海市农业土壤中铜锌镍的环境容量

南海市是我国经济最发达的县级市之一,工业门类多,布局分散,工业“三废”对土壤环境产生一定影响。研究结果表明,土壤中铜、锌、镍的容量分别为１８５ ．５８ ｋｇ／ｈ ｍ ２ 、２９２ ．８８ ｋｇ／ｈ ｍ ２ 、６３ ．９２ ｋｇ／ｈ ｍ ２ 。丘陵地区容最较大,其次是基塘区,平原地区较小。重金属污染型企业分布密集的地区环境容量较小。土壤环境容量与元素含量和最大允许含量有关。     

International externalities, strategic interaction, and domestic politics

Domestic politics can sometimes play an influential role when externalities have strategic and international implications. If voters delegate the choice to policymakers and if individual countries independently determine their environmental policy using a consumption tax on the emissions generating good, the result could be an outcome that is inferior to the one preferred by the median voter in the absence of delegation. On the other hand, if the international externality is unilateral in nature, rather than reciprocal, we find that delegation is largely irrelevant, since voters’ choice of policymaker is no longer strategic in character. Similarly, if voters anticipate policymakers successfully coordinating their policies at a later stage, there also will be no difference between the policymakers’ and the median voters’ aggregate weighting of environmental emissions.     

Externalities, Market Power, and Resource Extraction

This article analyzes the effect of market power in the presence of dynamic and biological externalities. When several countries harvest fish in international waters the evolution of fish population is affected by their joint action, thus generating a biological and a dynamic externality. If there is trade, the market-clearing prices depend on the harvesting and consumption in all countries. Therefore, market-clearing prices also generate an externality. We find a subgame perfect Cournot–Nash equilibrium and study the conditions under which it may be efficient. We also analyze the role of different externalities in generating inefficiency.     

Risk,Risk Aversion,and On-Farm Soil Depletion

This paper studies the production and attendant soil depletion choices of a risk-averse farmer in two related models. The first is a two-date model with uncertainty in both production and end-of-period land price. The second is a three-date model in which production and consumption choices are made in both periods, but there is uncertainty only in the second period. In both models, the paper identifies plausible conditions under which a higher level of initial farmer wealth and/or a lower level of production and land risk lead to a lower level of output and, as a result, a lower level of output-induced soil depletion.     

湛江特呈岛红树林植物群落的结构和动态特征

对特呈岛红树林植被进行多次和全面的调查,通过采用格子样的方法,选取面积为100～800 m^2的样地,每片样地再分成若干10 m×10 m的样方,对红树林样地内的植物进行每木测量,记录各植物的种名、胸径、高度、冠幅等,并进行重要性以及多样性等常规的群落分析,判定该地区植被的生长特征以及研究其演替动态变化。结果表明：①面积较大的群落主要有3个类型,即白骨壤群落（Avicennia marina）、白骨壤＋红海榄群落（Avicennia marina＋Rhizophora stylosa）、白骨壤-桐花树群落（Avicennia marina-Aegiceras corniculatum）;其它面积较小的群落有：白骨壤＋红海榄-木榄＋桐花树群落（vicennia marina＋Rhizophora stylosa-Bruguiera gymnorrhiza＋Aegiceras corniculatum）、红海榄＋木榄群落（Rhizophora stylosa＋Bru-guiera gymnorrhiza）;②在3个主要群落中,优势种的苗木和小树相对较少,优势种群的年龄结构均为衰退型;③各群落的Simpson指数关系为：白骨壤＋红海榄群落﹥红海榄＋木榄群落﹥白骨壤＋红海榄—木榄＋桐花树群落﹥白骨壤—桐花树群落﹥白骨壤群落;白骨壤群落的重要值为300,为典型的单优群落;④特呈岛的白骨壤群落是中国该类群落中面积最大的,目前长势良好,无病虫害,并且红树林外缘的白骨壤枝干在波浪冲刷或人为原因下,受到较严重的侵蚀,其幼树在林外缘基本无法存活,需要加强保护,对其生理生态学特征也值得进一步深入研究。     

Stochastic Pollution, Permits, and Merger Incentives

Pollution permit regulations introduce nonlinearities into the objective function of a polluting firm. We develop a microeconomic model to show the effects these nonlinearities might have upon firm decisions when emissions are stochastic. Under perfect competition the fraction of planned pollution covered by permits is shown to be separable from planned production. We also demonstrate that permit management incentives may motivate a merger of otherwise independent firms. Incentives to petition for “bubble” coverage are also considered. The model is studied under risk neutrality and risk aversion. Imperfectly competitive situations in the output and permit markets are also analyzed.     

Externalities, pigouvian corrections, and risk attitudes

We examine the influence of risk attitudes on the provision of an externality and on the proper size of Pigouvian correction when the externality is a random variable whose distribution is affected by an observable externality-generating activity. An intervening technology relates changes in this observable activity to the probability distribution of the relevant externality. Unlike the now-standard result in the theory of the firm involving the influence of risk attitudes on output levels, we cannot conclude that increases in risk aversion will lead necessarily to a reduction in the level of the externality. Our results are applied to a wide range of market failures.