Effect of epibiosis on the fitness of the sandy shore snail<Emphasis Type="Italic"> Batillaria zonalis</Emphasis> in Hong Kong

Batillaria zonalis is a common snail on Hong Kong sandy shores, occupying the low-mid shore. Shells of B. zonalis (basibiont) are often fouled with the rock oyster Saccostrea cucullata and the barnacle Balanus reticulatus (epibiont). This epibiotic interaction has a negative impact on the fitness of B. zonalis in terms of impairing fecundity, mobility and metabolism of fouled individuals. During the reproductive season, fouled snails had lower Gonadosomatic Index and fewer egg-bearing individuals than non-fouled snails. Fouled snails crawled in a more tortuous pathway and with lower speed when compared with non-fouled snails. Reduction in oxygen consumption and metabolic rate in fouled snails further suggested the restriction in mobility of B. zonalis by the epibionts. Glycogen content in the foot muscle tissues and hepatopancreas of fouled and non-fouled snails was, however, similar, revealing epibiosis does not influence the energy storage of B. zonalis. Mortality of fouled and non-fouled snails was similar under laboratory conditions, suggesting epibiosis does not influence the survivorship of B. zonalis in Hong Kong. Impairment in the fitness of fouled B. zonalis indicates that epibiosis can influence the population dynamics of B. zonalis in Hong Kong.Communicated by T. Ikeda, Hakodate     

Lymphatic transport of inhaled diesel particles in the lungs of rats and guinea pigs exposed to diluted diesel exhaust

Factors influencing the disposition of the inhaled diesel particles were studied by analyzing the deposition of radioactively labelled diesel particles in the respiratory system, by determining the specific function of alveolar cellular mechanisms in the primary defense against inhaled particles and by identifying the important role of the lymphatic system in the lung clearance of experimental animals exposed to diluted emissions from a diesel engine. Radioactive ¹³¹Barium was used as a tracer of diesel particles and the deposition efficiency was determined to be 15%±6% of the inhaled dose in the Fischer 344 rat strain. The number of cells obtained by bronchial lavage increased significantly after a prolonged exposure to a concentration of 1500 μg/m³ of diesel particles. The increased cell number was more than twofold, contained two distinct cell populations (alveolar macrophages and neutrophils) and represented a reactive mobilization of the defense mechanisms in the organism. Light microscopy studies investigated the role of lymphatic transport of the particulate matter and revealed that the peribrochial and perivascular aggregates of lymphoid tissue contained diesel particles even after short exposure periods at low dose levels. With the increasing burden of particles in the respiratory system, the coloration of hilar and mediastinal lymph nodes continuously changed to gray and finally to dark black, depending upon the dose level and exposure. However, at all exposure levels, most of the diesel particles in the alveoli were phagocytized by an increased alveolar cellular defence and particle-containing macrophages were actively moving towards the mucociliary escalator or towards lymphatic channels leading to peribronchial lymphoid aggregates and bronchial or mediastinal lymph nodes. In the lymph nodes, alveolar macrophages containing diesel particles were found mostly in the afferent subcapsular lymphatic vessels and marginal sinuses. In the later stages, cellular structure disintegrated and large aggregates of particulate matter were dispersed throughout the medullary cords with increasing accumulation towards the hilus. It is concluded that the lymphoid aggregates and lymphatic nodes play an important role in sequestering diesel particles or particle-containing phagocytizing cells and provide a pathway, in addition to the mocociliary clearance for particulate removal from the deep pulmonary region.     

Introduction to and experimental conditions during the first year of the GMR chronic inhalation studies of diesel exhaust

A chronic exposure study was initiated to determine the effects of diesel exhaust on the health of experimental animals. For this purpose, test atmospheres of clean air (control) or freshly diluted diesel exhaust at concentrations of 250, 750, and 1500 μg/m³ were supplied to four 12.6 m³ inhalation chambers which housed rats and guinea pigs. Diesel aerosol size and concentration, as well as chamber temperature and relative humidity, were continually monitored and controlled to maintain the exposure dose levels and an environment of 22±2°C and 50%±20% relative humidity. The concentrations of CO and NO_x were found to be 5.8±1.0 mg/m³ and 7.9±1.0 mg/m³ above ambient in the chamber containing 1500 μg/m³ of particulate. Animals were supplied from the chambers, on a random basis, for both intramural and extramural studies throughout the exposure period. The experiment ran uninterrupted for over twelve months with mean diesel particle mass concentrations within 2% of the target values.     

Participatory evaluation of collaborative and integrated water management: Insights from the field

The Maitland Watershed Partnerships (MWPs) is a multi-stakeholder forum established in 1999 in an agricultural watershed in Southwestern Ontario, Canada. This paper presents 10 lessons emerging from the participatory evaluation of the MWPs carried out in 2005. As suggested in the literature and highlighted by the experience of the MWPs, multi-stakeholder collaboration and integration is about learning how to cope with and take advantage from difference, diversity and divergence. Watershed partnerships are arenas in which different types of knowledges, diverse values and divergent sectoral perspectives, are confronted. In this context, inter-organizational leadership is essential to develop and sustain collaborative advantage among multiple public, private and civil society actors. According to the experience of the MWPs, however, embracing difference, diversity and divergence should go well beyond initial planning stages. Instead, pursuing compromise and agreement should also be at the forefront during the monitoring and evaluation stages. Negotiating indicators for monitoring and evaluation that can address water management both as a social process and a technical process is critical, as is making the distinction between partnership outputs and partnership outcomes.     

Some aspects of toxic contaminants in herbal medicines

A World Health Organisation survey indicated that about 70-80% of the world populations rely on non-conventional medicine mainly of herbal sources in their primary healthcare. In recent years, we have witnessed the increasing growth in popularity of over-the-counter (OTC) health foods, nutraceuticals, and medicinal products from plants or other natural sources in developed countries. This indirectly indicates that the public is not satisfied with their orthodox medical (OM) treatment. Such increase in popularity has also brought concerns and fears over the professionalism of practitioners, and quality, efficacy and safety of their treatment methods and products from herbal and natural sources available in the market. Over the past decade several news-catching episodes in developed communities indicated adverse effects, sometimes life threatening, allegedly arisen consequential to taking of OTC herbal products or traditional medicines from various ethnic groups. These OTC products may be contaminated with excessive or banned pesticides, microbial contaminants, heavy metals, chemical toxins, and for adulterated with orthodox drugs. Excessive or banned pesticides, heavy metals and microbial contaminants may be related to the source of these herbal materials, if they are grown under contaminated environment or during collection of these plant materials. Chemical toxins may come from unfavourable or wrong storage conditions or chemical treatment due to storage. The presence of orthodox drugs can be related to unprofessional practice of manufacturers. Some of these environment related factors can be controlled by implementing standard operating procedures (SOP) leading to Good Agricultural Practice (GAP), Good Laboratory Practice (GLP), Good Supply Practice (GSP) and Good Manufacturing Practice (GMP) for producing these medicinal products from herbal or natural sources. The public's belief that herbal and natural products are safer than synthetic medicines can only be ascertained by imposing regulatory standards on these products that should be manufactured using these Good Practices. Using Chinese medicines, as examples, this paper illustrate how advances in chemical and biomedical analysis would help to detect intentional and unintentional toxic contaminants in herbal substances. The paper also summarises how modernization and progress are being carried out to get the best out of Chinese medicines for public healthcare.     

Nutrients on Asphalt Parking Surfaces in an Urban Environment

Amounts of readily soluble nutrients on asphalt parking lot surfaceswere measured at four locations in metropolitan Phoenix, Arizona, U.S.A. Using a rainfall simulator, short intense rainfall events were generated to simulate `first flush' runoff. Samples were collected from 0.3 m² sections of asphalt at 8 to 10 sites on each of four parkinglots, during the pre-monsoon season in June-July 1998 and analyzed for dissolved NO₃ ^--N, NH₄ ⁺-N, soluble reactive phosphate (SRP), and dissolved organic carbon (DOC). Runoff concentrations varied considerably for NO₃ ^--N and NH₄ ⁺-N (between 0.1 and 115.8 mg L^-1) and DOC (26.1 to 295.7 mg L^-1), but less so for SRP (0.1 to 1.0 mg L^-1), representing average surface loadings of 191.3, 532.2, and 1.8 mg m^-2 respectively. Compared with similar data collected from undeveloped desert soil surfaces outside the city, loadings of NO₃ ^--N and NH₄ ⁺-N on asphalt surfaces were greater by factors of 91 and 13, respectively. In contrast, SRP loads showed little difference between asphalt and desert surfaces. Nutrient fluxes in runoff from a storm that occurred shortly after the experiments were used to estimate input-output budgets for 3 of the lots under study. Measured outputs of DOC and SRP were similar to those predicted using rainfall and experimentally determined surface loadings, but for NH₄ ⁺-N and particularly for NO₃ ^--N, estimated rainfall inputs and surface runoff were significantly higher than exports in runoff. This suggests that parking lots may be important sites for nutrient accumulation and temporary storage in arid urban catchments.     

Intermediate inhibition in the heterogeneous UV-catalysis using a TiO2 suspension system

Langmuir-Hinshelwood (L-H) kinetic expression was used to develop a basic mathematical model, which could describe the inhibition of intermediates in the photocatalysis of 2-chlorophenol (2-CP) in a suspended TiO2 system. Results showed that the photocatalytic oxidation of 2-chlorophenol followed the L-H type behavior and the reaction by-products displayed an inhibiting effect on the degradation rate. The inhibition was estimated by comparing to observed and estimated half-lives. The higher the initial concentration of 2-chlorophenol, the higher the inhibition of photocatalytic reaction. The L-H kinetic has been modified slightly in this study to rationalize the contrast of inhibited behavior and to improve in favor of a surface reaction. The concentrations of 2-chlorophenol were investigated ranging from 7.78 x 10(-5) to 7.78 x 10(-4) mol l(-1). The degradation of 2-chlorophenol in this reaction condition approximates a first-order kinetics to near-complete degradation. Calculated kinetic profiles are in an excellent agreement with the experimental observation. The results of the theoretical analysis can be used to estimate reaction rates in different initial concentrations of target compound.     

Synthesis and spatial dynamics of socio-economic metabolism and land use change of Taipei Metropolitan Region

Ever since the concept of metabolism was extended from biological science by social scientists to analyze human systems, socio-economic metabolism has been extensively applied to explore resource consumption, asset accumulation, waste emissions, and complex processes of land use change in a socio-economic system. Current research in socio-economic metabolism and land use change has used accounting approaches for macroscopic comparisons of countries and regions. However, socio-economic metabolism has seldom been applied to the analysis of land use change. To simulate the spatial-temporal dynamics of socio-economic metabolism and land use change, this study adopts a spatial system modeling method to develop a Socio-Economic Metabolism and Land Use Change (SEMLUC) model for the Taipei Metropolitan Region. The simulation results illustrate that the Taipei Metropolitan Region is highly dependent on inflows of non-renewable energy and exhibits a spatial hierarchy of non-renewable energy consumption centering on Taipei's Main station. Additionally, urban assets provide feedback to natural and agricultural systems to extract additional resource inflows which, driven by the maximum power principle, accelerate the convergence of energy flows toward urban assets. Accumulating urban assets also facilitates inflows of non-renewable material to nearby cells thereby enhancing land use conversion to urban areas. This work also demonstrates the capability of ArcGIS software in simulating socio-economic metabolism and land use change in an urban system.