The feral horse foot. Part B : radiographic, gross visual and histopathological parameters of foot health in 100 Australian feral horses

Background It has been proposed that the feral horse foot is a benchmark model for foot health in horses. However, the foot health of feral horses has not been formally investigated. Objectives To investigate the foot health of Australian feral horses and determine if foot health is affected by environmental factors, such as substrate properties and distance travelled. Methods Twenty adult feral horses from five populations (n = 100) were investigated. Populations were selected on the basis of substrate hardness and the amount of travel typical for the population. Feet were radiographed and photographed, and digital images were surveyed by two experienced assessors blinded to each other's assessment and to the population origin. Lamellar samples from 15 feet from three populations were investigated histologically for evidence of laminitis. Results There was a total of 377 gross foot abnormalities identified in 100 left forefeet. There were no abnormalities detected in three of the feet surveyed. Each population had a comparable prevalence of foot abnormalities, although the type and severity of abnormality varied among populations. Of the three populations surveyed by histopathology, the prevalence of chronic laminitis ranged between 40% and 93%. Conclusions Foot health appeared to be affected by the environment inhabited by the horses. The observed chronic laminitis may be attributable to either nutritional or traumatic causes. Given the overwhelming evidence of suboptimal foot health, it may not be appropriate for the feral horse foot to be the benchmark model for equine foot health.

Impact of a change in tillage and crop residue management practice on soil chemical and microbiological properties in a cereal-producing red duplex soil in NSW, Australia

The effect of a change of tillage and crop residue management practice on the chemical and micro-biological properties of a cereal-producing red duplex soil was investigated by superimposing each of three management practices (CC: conventional cultivation, stubble burnt, crop conventionally sown; DD: direct-drilling, stubble retained, no cultivation, crop direct-drilled; SI: stubble incorporated with a single cultivation, crop conventionally sown), for a 3-year period on plots previously managed with each of the same three practices for 14 years. A change from DD to CC or SI practice resulted in a significant decline, in the top 0-5 cm of soil, in organic C, total N, electrical conductivity, NH4-N, NO3-N, soil moisture holding capacity, microbial biomass and CO2 respiration as well as a decline in the microbial quotient (the ratio of microbial biomass C to organic C; P <0.05). In contrast, a change from SI to DD or CC practice or a change from CC to DD or SI practice had only negligible impact on soil chemical properties (P >0.05). However, there was a significant increase in microbial biomass and the microbial quotient in the top 0-5 cm of soil following the change from CC to DD or SI practice and with the change from SI to DD practice (P <0.05). Analysis of ester-linked fatty acid methyl esters (EL-FAMEs) extracted from the 0- to 5-cm and 5- to 10-cm layers of the soils of the various treatments detected changes in the FAME profiles following a change in tillage practice. A change from DD practice to SI or CC practice was associated with a significant decline in the ratio of fungal to bacterial fatty acids in the 0- to 5-cm soil (P <0.05). The results show that a change in tillage practice, particularly the cultivation of a previously minimum-tilled (direct-drilled) soil, will result in significant changes in soil chemical and microbiological properties within a 3-year period. They also show that soil microbiological properties are sensitive indicators of a change in tillage practice.

Chemical and bioanalytical assessment of coal seam gas associated water

A comprehensive study was undertaken involving chemical (inorganic and organic) and bioanalytical (a suite of 14 in vitro bioassays) assessments of coal seam gas (coal bed methane) associated water (CSGW) in Queensland, Australia. CSGW is a by-product of the gas extraction process and is generally considered as water of poor quality. This was done to better understand what is known about the potential biological and environmental effects associated with the organic constituents of CSGW in Australia. In Queensland, large amounts of associated water must be withdrawn from coal seams to allow extraction of the gas. CSGW is disposed of via release to surface water, reinjected to groundwater or reused for irrigation of crops or pasture, supplied for power station cooling and or reinjected specifically to augment drinking water aquifers. Groundwater samples were collected from private wells tapping into the Walloon Coal Measures, the same coal aquifer exploited for coal seam gas production in the Surat Basin, Australia. The inorganic characteristics of these water samples were almost identical to the CSGW entering the nearby gas company operated Talinga-Condabri Water Treatment Facility. The water is brackish with a pH of 8 to 9, high sodium, bicarbonate and chloride concentrations but low calcium, magnesium and negligible sulphate concentrations. Only low levels of polyaromatic hydrocarbons (PAHs) were detected in the water samples, and neither phenols nor volatile organic compounds were found. Results from the bioassays showed no genotoxicity, protein damage, or activation of hormone receptors (with the exception of the estrogen receptor). However, five of the 14 bioassays gave positive responses: an arylhydrocarbon-receptor gene activation assay (AhR-CAFLUX), estrogenic endocrine activity (ERα-CALUX), oxidative stress response (AREc32), interference with cytokine production (THP1-CPA) and non-specific toxicity (Microtox). The observed effects were benchmarked against known water sources and were similar to secondary treated wastewater effluent, stormwater and surface water. As mixture toxicity modelling demonstrated, the detected PAHs explained less than 5% of the observed biological effects.

Biological monitoring and Biological Limit Values (BLV): the strategy of the European Union

Occupational standards concerning allowable concentrations of chemical compounds in the ambient air of workplaces have been established in several countries worldwide. With the integration of the European Union (EU), there has been a need of establishing harmonised Occupational Exposure Limits (OEL). The European Commission Directive 95/320/EC of 12 July 1995 has given the tasks to a Scientific Committee for Occupational Exposure Limits (SCOEL) to propose, based on scientific data and where appropriate, occupational limit values which may include the 8-h time-weighted average (TWA), short-term limits/excursion limits (STEL) and Biological Limit Values (BLVs). In 2000, the European Union issued a list of 62 chemical substances with Occupational Exposure Limits. Of these, 25 substances received a "skin" notation, indicating that toxicologically significant amounts may be taken up via the skin. For such substances, monitoring of concentrations in ambient air may not be sufficient, and biological monitoring strategies appear of potential importance in the medical surveillance of exposed workers. Recent progress has been made with respect to formulation of a strategy related to health-based BLVs.

The Cressbrook Creek alluvial aquifer system, Southeast Queensland : hydrochemistry and isotopes to determine hydrological processes and response to floods

This study developed an understanding of hydrological processes within the Cressbrook Creek catchment of the upper Brisbane River, in particular for the alluvial aquifers. Those aquifers within the lower catchment are used for intensive irrigation, and have been impacted by long-term drought followed by flooding. The study utilised water chemistry, isotopic characters and hydraulic measurements to determine factors such as recharge, links between creeks and groundwater, and variations in water quality. The catchment-wide study will enable improved management of the local water resources.

Species and Hybrids: Chemical and Physical Foliar Attributes and Implications for Herbivory.

Hybridization is an important biological phenomenon that can be used to understand the evolutionary process of speciation of plants and their associated pests and diseases. Interactions between hybrid plants and the herbivores of the parental taxa may be used to elucidate the various cues being used by the pests for host location or other processes. The chemical composition of plants, and their physical foliar attributes, including leaf thickness, trichome density, moisture content and specific leaf weight were compared between allopatric pure and commercial hybrid species of Corymbia, an important subtropical hardwood taxon. The leaf-eating beetle Paropsis atomaria, to which the pure taxa represented host (C. citriodora subsp. variegata) and non-host (C. torelliana) plants, was used to examine patterns of herbivory in relation to these traits. Hybrid physical foliar traits, chemical profiles, and field and laboratory beetle feeding preference, while showing some variability, were generally intermediate to those exhibited by parent taxa, thus suggesting an additive inheritance pattern. The hybrid susceptibility hypothesis was not supported by our field or laboratory studies, and there was no strong relationship between adult preference and larval performance. The most-preferred adult host was the sympatric taxon, although this species supported the lowest larval survival, while the hybrid produced significantly smaller pupae than the pure species. The results are discussed in relation to plant chemistry and physical characteristics. The findings suggest a chemical basis for host selection behavior and indicate that it may be possible to select for resistance to this insect pest in these commercially important hardwood trees.

Synthesis, Reactivity and Biological Activity of 17β-HSD1 Inhibitors Based on a Thieno[2,3-d]pryrimidin-4(3H)-one Core

Breast cancer is the most common cancer in women in Western countries. In the early stages of development most breast cancers are hormone-dependent, and estrogens, especially estradiol, have a pivotal role in their development and progression. One approach to the treatment of hormone-dependent breast cancers is to block the formation of the active estrogens by inhibiting the action of the steroid metabolising enzymes. 17beta-Hydroxysteroid dehydrogenase type 1 (17beta-HSD1) is a key enzyme in the biosynthesis of estradiol, the most potent female sex hormone. The 17beta-HSD1 enzyme catalyses the final step and converts estrone into the biologically active estradiol. Blocking 17beta-HSD1 activity with a specific enzyme inhibitor could provide a means to reduce circulating and tumour estradiol levels and thus promote tumour regression. In recent years 17beta-HSD1 has been recognised as an important drug target. Some inhibitors of 17beta-HSD1 have been reported, however, there are no inhibitors on the market nor have clinical trials been announced. The majority of known 17beta-HSD1 inhibitors are based on steroidal structures, while relatively little has been reported on non-steroidal inhibitors. As compared with 17beta-HSD1 inhibitors based on steroidal structures, non-steroidal compounds could have advantages of synthetic accessibility, drug-likeness, selectivity and non-estrogenicity. This study describes the synthesis of large group of novel 17beta-HSD1 inhibitors based on a non-steroidal thieno[2,3-d]pyrimidin-4(3H)-one core. An efficient synthesis route was developed for the lead compound and subsequently employed in the synthesis of thieno[2,3-d]pyrimidin-4(3H)-one based molecule library. The biological activities and binding of these inhibitors to 17beta-HSD1 and, finally, the quantitative structure activity relationship (QSAR) model are also reported. In this study, several potent and selective 17beta-HSD1 inhibitors without estrogenic activity were identified. This establishment of a novel class of inhibitors is a progressive achievement in 17beta-HSD1 inhibitor development. Furthermore, the 3D-QSAR model, constructed on the basis of this study, offers a powerful tool for future 17beta-HSD1 inhibitor development. As part of the fundamental science underpinning this research, the chemical reactivity of fused (di)cycloalkeno thieno[2,3-d]pyrimidin-4(3H)-ones with electrophilic reagents, i.e. Vilsmeier reagent and dimethylformamide dimethylacetal, was investigated. These findings resulted in a revision of the reaction mechanism of Vilsmeier haloformylation and further contributed to understanding the chemical reactivity of this compound class. This study revealed that the reactivity is dependent upon a stereoelectronic effect arising from different ring conformations.

Chemical and source characterisation of size-segregated urban air particulate matter

Recent epidemiological studies have shown a consistent association of the mass concentration of urban air thoracic (PM10) and fine (PM2.5) particles with mortality and morbidity among cardiorespiratory patients. However, the chemical characteristics of different particulate size ranges and the biological mechanisms responsible for these adverse health effects are not well known. The principal aims of this thesis were to validate a high volume cascade impactor (HVCI) for the collection of particulate matter for physicochemical and toxicological studies, and to make an in-depth chemical and source characterisation of samples collected during different pollution situations. The particulate samples were collected with the HVCI, virtual impactors and a Berner low pressure impactor in six European cities: Helsinki, Duisburg, Prague, Amsterdam, Barcelona and Athens. The samples were analysed for particle mass, common ions, total and water-soluble elements as well as elemental and organic carbon. Laboratory calibration and field comparisons indicated that the HVCI can provide a unique large capacity, high efficiency sampling of size-segregated aerosol particles. The cutoff sizes of the recommended HVCI configuration were 2.4, 0.9 and 0.2 μm. The HVCI mass concentrations were in a good agreement with the reference methods, but the chemical composition of especially the fine particulate samples showed some differences. This implies that the chemical characterization of the exposure variable in toxicological studies needs to be done from the same HVCI samples as used in cell and animal studies. The data from parallel, low volume reference samplers provide valuable additional information for chemical mass closure and source assessment. The major components of PM2.5 in the virtual impactor samples were carbonaceous compounds, secondary inorganic ions and sea salt, whereas those of coarse particles (PM2.5-10) were soil-derived compounds, carbonaceous compounds, sea salt and nitrate. The major and minor components together accounted for 77-106% and 77-96% of the gravimetrically-measured masses of fine and coarse particles, respectively. Relatively large differences between sampling campaigns were observed in the organic carbon content of the PM2.5 samples as well as the mineral composition of the PM2.5-10 samples. A source assessment based on chemical tracers suggested clear differences in the dominant sources (e.g. traffic, residential heating with solid fuels, metal industry plants, regional or long-range transport) between the sampling campaigns. In summary, the field campaigns exhibited different profiles with regard to particulate sources, size distribution and chemical composition, thus, providing a highly useful setup for toxicological studies on the size-segregated HVCI samples.

Critical review on the stability of illicit drugs in sewers and wastewater samples

Wastewater-based epidemiology (WBE) applies advanced analytical methods to quantify drug residues in wastewater with the aim to estimate illicit drug use at the population level. Transformation processes during transport in sewers (chemical and biological reactors) and storage of wastewater samples before analysis are expected to change concentrations of different drugs to varying degrees. Ignoring transformation for drugs with low to medium stability will lead to an unknown degree of systematic under- or overestimation of drug use, which should be avoided. This review aims to summarize the current knowledge related to the stability of commonly investigated drugs and, furthermore, suggest a more effective approach to future experiments. From over 100 WBE studies, around 50 mentioned the importance of stability and 24 included tests in wastewater. Most focused on in-sample stability (i.e., sample preparation, preservation and storage) and some extrapolated to in-sewer stability (i.e., during transport in real sewers). While consistent results were reported for rather stable compounds (e.g., MDMA and methamphetamine), a varying range of stability under different or similar conditions was observed for other compounds (e.g., cocaine, amphetamine and morphine). Wastewater composition can vary considerably over time, and different conditions prevail in different sewer systems. In summary, this indicates that more systematic studies are needed to: i) cover the range of possible conditions in sewers and ii) compare results more objectively. To facilitate the latter, we propose a set of parameters that should be reported for in-sewer stability experiments. Finally, a best practice of sample collection, preservation, and preparation before analysis is suggested in order to minimize transformation during these steps.

Synthesis and biological evaluation of novel 2-aralkyl-5-substituted-6-(4 `-fluorophenyl)-imidazo2,1-b]1,3,4]thiadiazole derivatives as potent anticancer agents

Levamisole, the imidazo2,1-b]thiazole derivative has been reported as a potential antitumor agent. In the present study, we synthesized, characterized and evaluated biological activity of its novel analogues with substitution in the aralkyl group and on imidazothiadiazole molecules with same chemical backbone but different side chains namely 2-aralkyl-6-(4'-fluorophenyl)-imidazo2,1-b]1,3,4]thiadiazoles (SCR1), 2-aralkyl-5-bromo-6-(4'-fluorophenyl)-imidazo2,1-b]1,3,4]-thiadiaz oles (SCR2), 2-aralkyl-5-formyl-6-(4'-fluorophenyl)-imidazo2,1-b]1,3,4]-thiadia zoles (SCR3) and 2-aralkyl-5-thiocyanato-6-(4'-fluorophenyl)-imidazo2,1-b]1,3,4]-th iadiazoles (SCR4) on leukemia cells. The cytotoxic studies showed that 3a, 4a, and 4c exhibited strong cytotoxicity while others had moderate cytotoxicity. Among these we chose 4a (IC50, 8 mu M) for understanding its mechanism of cytotoxicity. FACS analysis in conjunction with mitochondrial membrane potential and DNA fragmentation studies indicated that 4a induced apoptosis without cell cycle arrest suggesting that it could be used as a potential chemotherapeutic agent. (C) 2011 Elsevier Masson SAS. All rights reserved.

Spatial Analysis and Characterisation of Lentic Ecosystems: A Case Study of Varthur Lake, Bangalore

Lentic ecosystems vital functions such as recycling of nutrients, purification of water, recharge of groundwater,augmenting and maintenance of stream flow and habitat provision for a wide variety of flora and fauna along with their recreation values necessitates their sustainable management through appropriate conservation mechanisms. Failure to restore these ecosystems will result in extinction of species or ecosystem types and cause permanent ecological damage. In Bangalore, lentic ecosystems (for example lakes) have played a prominent role serving the needs of agriculture and drinking water. But the burgeoning population accompanied by unplanned developmental activities has led to the drastic reduction in their numbers (from 262 in 1976 to 81). The existing water bodies are contaminated by residential, agricultural, commercial and industrial wastes/effluents. In order to restore the ecosystem, assessment of the level of contamination is crucial. This paper focuses on characterisation and restoration aspects of Varthur lake based on hydrological, morphometric, physical-chemical and socio-economic investigations for a period of six months covering post monsoon seasons. The results of the water quality analysis show that the lake is eutrophic with high concentrations of phosphorous and organic matter. The morphometric analysis indicates that the lake is shallow in relation to its surface area. Socio-economic analyses show dependence of local residents for irrigation, fodder, etc. These analyses highlight the need and urgency to restore the physical, chemical and biological integrity through viable restoration and sustainable watershed management strategies, which include pollution abatement, catchment treatment, desilting of the lake and educating all stakeholders on the conservation and restoration of lake ecosystems.

Monograph on Essentials in Limnology and GIS

Aquatic ecosystems are dynamic and depend on various interdependent and inter-related factors that are vital for their existence and in maintaining the ecological balance. Various anthropogenic activities have impaired ecological conditions in many ecosystems. This monograph gives an account of the essentials in limnology, which helps in understanding the nature and extent of the problems and also provides an insight into the use of Geographic Information System as an effective tool for resource inventorying, monitoring and management. The monograph consists of four chapters, and the first one gives an overall view of the inland aquatic bodies as complex ecological systems. It begins with the formation of lakes, and the various physical, chemical and biological factors that determine these ecosystems. The physical factors covered include morphometry, density, light, etc., and the lake chemistry determined by various anions and cations are discussed in detail. The biological parameters include phytoplankton, zooplankton, waterfowl and fish communities that play an important role in freshwater biodiversity, and are presented with diagrams for easy understanding. The monograph gives an in depth view of the lake zones, productivity, and seasonal changes in the lake community with various energy relationships. The concept of food chain and food web in an aquatic ecosystem is also presented with illustrations. Lastly, the various anthropogenic activities that have deteriorated the quality of water are listed with the restoration strategies.

High-quality ZnO nanorod based flexible devices for electronic and biological applications

Vertically aligned zinc oxide nanorods (ZnO NRs) were synthesized on kapton flexible sheets using a simple and cost-effective three-step process (electrochemical seeding, annealing under ambient conditions, and chemical solution growth). Scanning electron microscopy studies reveal that ZnO NRs grown on seed-layers, developed by electrochemical deposition at a negative potential of 1.5 V over a duration of 2.5 min and annealed at 200 degrees C for 2 h, consist of uniform morphology and good chemical stoichiometry. Transmission electron microscopy analyses show that the as-grown ZnO NRs have single crystalline hexagonal structure with a preferential growth direction of < 001 >. Highly flexible p-n junction diodes fabricated by using p-type conductive polymer exhibited excellent diode characteristics even under the fold state.

Enhancing the mechanical and biological performance of a metallic biomaterial for orthopedic applications through changes in the surface oxide layer by nanocrystalline surface modification

Nanostructured metals are a promising class of biomaterials for application in orthopedics to improve the mechanical performance and biological response for increasing the life of biomedical implants. Surface mechanical attrition treatment (SMAT) is an efficient way of engineering nanocrystalline surfaces on metal substrates. In this work, 316L stainless steel (SS), a widely used orthopedic biomaterial, was subjected to SMAT to generate a nanocrystalline surface. Surface nanocrystallization modified the nature of the oxide layer present on the surface. It increased the corrosion-fatigue strength in saline by 50%. This increase in strength is attributed to a thicker oxide layer, residual compressive stresses, high strength of the surface layer, and lower propensity for intergranular corrosion in the nanocrystalline layer. Nanocrystallization also enhanced osteoblast attachment and proliferation. Intriguingly, wettability and surface roughness, the key parameters widely acknowledged for controlling the cellular response remained unchanged after nanocrystallization. The observed cellular behavior is explained in terms of the changes in electronic properties of the semiconducting passive oxide film present on the surface of 316L SS. Nanocrystallization increased the charge carrier density of the n-type oxide film likely preventing denaturation of the adsorbed cell-adhesive proteins such as fibronectin. In addition, a net positive charge developed on the otherwise neutral oxide layer, which is known to facilitate cellular adhesion. The role of changes in the electronic properties of the oxide films on metal substrates is thus highlighted in this work. This study demonstrates the advantages of nanocrystalline surface modification by SMAT for processing metallic biomaterials used in orthopedic implants.