Elemental composition of aquaculture fish from West Bengal, India: nutrition versus food safety.

Aquaculture production continues to grow in West Bengal, where on average people consume 8.2 kg capita-1 of fish each year, and an extensive mosaic of aquaculture ponds has developed along the River Hugli as clay pits are repurposed. The adjacent brickworks and industry (especially tanneries) are a source of environmental pollution, with potential for bioaccumulation of potentially harmful elements (PHEs) in fish farmed in these ponds. Fish from aquaculture present an opportunity to meet food sufficiency in West Bengal; however, an investigation to assess their effectiveness for micronutrient supply balanced against food safety is required. Five ponds close to industrial brick manufacture (urban) and three from rural areas were assessed for the degree of pollution within their pond sediments and waters. Fish were also sampled from each location including a subset from the market in Kolkata to determine the concentrations of PHEs in their fish muscle tissue. Dietary intake and PHE loading were calculated for four fish species to evaluate their nutrient content with respect to recommended daily intakes for adults, e.g. calcium (Ca), potassium (K), magnesium (Mg), iron (Fe), zinc (Zn) and selenium (Se), and to establish whether the provisional maximum tolerable intakes (PMTIs) are exceeded for PHEs, e.g. aluminium (Al), arsenic (As), mercury (Hg), chromium (Cr), tin (Sn), copper (Cu) and lead (Pb). Preliminary results suggest that aquaculture is making an important contribution to nutrition, with fish being a good source of Se. However, in contrast to small wild-caught fish, aquaculture fish in the present study were poor sources of Fe, Ca and Zn. The fish also made substantial contributions (> 10%) to the PMTI of Hg and As. Therefore, there is an urgent need for ongoing monitoring and an expanded sampling programme, as well as research into approaches which might improve the nutritional quality of the farmed fish.

Electronic and optical properties of pristine and boron-nitrogen doped graphyne nanotubes.

First principle calculations with generalized gradient approximation were carried out to analyse the electronic and optical properties of armchair and zigzag graphyne nanotubes (GNTs). The possible application of these NTs in optoelectronic devices was also investigated. The GNTs were doped with boron (B) and nitrogen (N) atoms and the resulting band gap tuning was studied with respect to the B/N substitution site and increasing diameter of the NTs. The basis of this variation was examined using the partial density of states and crystal orbital Hamilton population analysis. A decreasing trend in the optical response was seen with an increase in the diameter of the NTs. The reported systems showed anisotropic behaviour in the low-energy region. The origin of the optical responses was monitored from the infrared to the UV region depending on the doping site of the B/N. As a result of the large band gap, low reflectivity and low refractive index, B/N GNTs have been established as a suitable system for novel optoelectronic devices. The strong absorption peaks in the UV region mean that they are a good choice for use in UV light protection.

A deterministic thermostat for controlling temperature using all degrees of freedom.

We propose a new thermostat that uses all the phase space variables for controlling temperature and thus differs from the existing thermostats that control either the kinetic (e.g., Nose Hoover) or the configurational (e.g., Braga Travis) degrees of freedom. Our thermostat is a special case of the set of equations proposed by Kusnezov et al. [Ann. Phys. 204, 155 (1990)] and is derived using the extended system method. We show that it generates a canonical phase-space distribution. The performance of the thermostat is compared with those of Nose-Hoover kinetic thermostat and Braga-Travis configurational thermostat for a system (i) in thermal equilibrium, (ii) subjected to sudden temperature changes, and (iii) in steady state non-equilibrium under thermal conduction. We observe that all three thermostats perform similarly for systems in equilibrium. However, our thermostat performs the best in the thermal conduction problem by generating a consistent temperature profile across the conduction length. We expect this thermostat to be useful in other non-equilibrium scenarios as well.

Arsenic speciation in polychaetes (Annelida) and sediments from the intertidal mudflat of Sundarban mangrove wetland, India.

This paper documents the concentration of total arsenic and individual arsenic species in four soft-bottom benthic polychaetes (Perenereis cultifera, Ganganereis sootai, Lumbrinereis notocirrata and Dendronereis arborifera) along with host sediments from Sundarban mangrove wetland, India. An additional six sites were considered exclusively for surface sediments for this purpose. Polychaetes were collected along with the host sediments and measured for their total arsenic content using inductively coupled plasma mass spectrometry. Arsenic concentrations in polychaete body tissues varied greatly, suggesting species-specific characteristics and inherent peculiarities in arsenic metabolism. Arsenic was generally present in polychaetes as arsenate (As(V) ranges from 0.16 to 0.50 mg kg(-1)) or arsenite (As(III) ranges from 0.10 to 0.41 mg kg(-1)) (30-53 % as inorganic As) and dimethylarsinic acid (DMA(V) <1-25 %). Arsenobetaine (AB < 16 %), and PO(4)-arsenoriboside (8-48 %) were also detected as minor constituents, whilst monomethylarsonic acid (MA(V)) was not detected in any of the polychaetes. The highest total As (14.7 mg kg(-1) dry wt) was observed in the polychaete D. arborifera collected from the vicinity of a sewage outfall in which the majority of As was present as an uncharacterised compound (10.3 mg kg(-1) dry wt) eluted prior to AB. Host sediments ranged from 2.5 to 10.4 mg kg(-1) of total As. This work supports the importance of speciation analysis of As, because of the ubiquitous occurrence of this metalloid in the environment, and its variable toxicity depending on chemical form. It is also the first work to report the composition of As species in polychaetes from the Indian Sundarban wetlands.

Detection of mycoplasma contamination in cell substrates using reverse transcription-PCR assays.

AIMS: To assess the limit of detection (LOD) and the feasibility of 16S rRNA-based reverse transcription-PCR (RT-PCR) assays for advanced detection of mycoplasma contamination in cell substrates. MATERIALS AND METHODS: The RT-PCR approach is based on detecting the 16S rRNA molecules that, in contrast to genomic bacterial DNA, are represented by multiple copies in mycoplasma cell. The number of 16S rRNA molecules in mycoplasma cells of five species i.e. Mycoplasma arginini, Myc. fermentans, Myc. hyorhinis, Myc. orale and Acholeplasma laidlawii, all known to be frequent cell line contaminants in industrial and research laboratories, was measured using molecular methods. The results of two independently prepared mycoplasma cultures harvested at the stationary phase of their growth showed that the 16S rRNA copy number per cell varied in the range from about 400 to 2000 copies, depending on species, but stayed close between different preparations of one species. The assessment of the LOD of the in-house 16S rRNA-based RT-PCR was performed using samples of MDCK cell culture spiked with different amounts of five aforementioned mycoplasma species. To minimize the bias in methods comparison, the LOD of the RT-PCR assay was expressed in terms of genome equivalents (GEs) and compared with that determined for highly optimized 16S rDNA-based mycoplasma testing methods previously described in scientific literature. CONCLUSIONS: The results of the study showed that the in-house 16S rRNA-based RT-PCR assay was able to reliably detect the presence of less than one mycoplasma GE that is at least 10-fold higher of the LOD previously determined for well-optimized 16S rDNA-based assays developed and described by other researchers. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of the study showed that rapid RT-PCR methods based on the detection of bacterial 16S rRNA are able to expedite mycoplasma testing of cell cultures (1-2 days vs 28 days) and to ensure the limits of detection comparable to that of currently used culture-based mycoplasma testing methods.

Attenuation of sulfur mustard toxicity by S-2(2-aminoethylamino)ethyl phenyl sulfide (DRDE-07) in mouse liver.

Sulfur mustard (SM) (bis-(2-chloroethyl) sulfide) is a chemical warfare agent. Evaluation of toxicity and protective effect of DRDE-07 (S-2(2-aminoethylamino)ethyl phenyl sulfide) was studied in mouse liver after SM challenging. Female mice were given orally 0.2 LD(50) of DRDE-07 (249 mg/kg body weight) and exposed percutaneously with 1.0 LD(50) of SM (8.1 mg/kg body weight). Gene expression profiles were determined using global genome microarray analysis at 3 days post-exposure. DRDE-07 alone treated animal showed significant upregulation to metabolism of xenobiotics by cytochrome P450 pathways. Genes related to cell adhesion molecules (CAMs), were downregulated. DRDE-07 pretreated SM exposed animals showed upregulation of xenobiotic cytochrome P450 pathway genes. Antigen presenting, cell adhesion molecules, cytokine, cytokine receptor metabolism, fatty acid metabolism, glutathione metabolism, cell cycle signaling pathway genes showed downregulation. The present study showed that SM-induced toxicity in mouse liver was attenuated by the pretreatment with DRDE-07.

Acid leachable trace metals in sediment cores from Sunderban Mangrove Wetland, India: an approach towards regular monitoring.

The paper presents the first document to identify the enrichment pattern of acid leachable trace metals (ALTMs) such as Fe, Mn, Cr, Cu, Ni, Pb, Cd, Co, Mo, Ag, As and Ba and their relationship with sediment quality parameters (pH, organic carbon, carbonates and texture) in core sediments (<63 microm particle size) from Indian Sunderban mangrove wetland, formed at the estuarine phase of the river Hugli (Ganges). Textural analysis reveals an overall predominance of mud. The results indicate that the change in pH values causes coagulation and precipitation of ALTMs. Fe and Mn have fairly close distribution patterns of enrichment in surface layers which might be ascribed to early diagnetic processes. The most prominent feature of ALTMs is the enrichment of Fe, Mn, Cr, Cu, Ni, Pb, and Ba in the surface-subsurface layers in the sediment cores, which is mainly attributed to the intense industrial and agricultural activities as well as drainage of untreated domestic sewage to this coastal region. The ALTMs also indicate their association with organic carbon and Fe-Mn oxyhydroxides. The enrichment is well--supported by the correlation, grouping and clustering of ALTMs in statistical analyses. Anthropogenic Factor values indicated ALTMs enrichment for all trace metals due to intense anthropogenic activities. Overall higher values of ALTMs in sediments in comparison to other Indian coastal regions indicate that they are mainly due to the uncontrolled anthropogenic activities in this mangrove estuarine complex. Statistical analyses suggest that five ALTMs (Cu, Pb, As, Mo, Ba) are attached to the organic particles and the clustering of elements separately also indicates that they are from external source. The result of the present study suggests the need for a regular monitoring program which will help to improve the quality of this potential wetland.

Quantification and source identification of polycyclic aromatic hydrocarbons in core sediments from Sundarban mangrove wetland, India.

The distribution and potential sources of 16 polycyclic aromatic hydrocarbons (PAHs) in sediment cores (<63 microm particle size) of the Sundarban mangrove wetland, northeastern coast of Bay of Bengal (India), were investigated by gas chromatography coupled to mass spectrometry. The total concentrations of 16 PAHs ( summation operator(16)PAHs) ranged from 132 to 2938 ng/g, with a mean of 634 ng/g, and the sum of 10 out of 16 priority PAHs ( summation operator(10)PAH) varied from 123 to 2441 ng/g, with a mean of 555 ng/g, and the 5 carcinogenic PAHs (benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, and dibenz[a,h]anthracene) accounted for 68-73% of the priority PAHs. Maximum concentrations of the sediment core were obtained at subsoil depth of 12-16 cm. The prevalence of four to six aromatic ring PAHs and cross-plots of specific isomer ratios such as phenanthrene/anthracene, fluoranthene/pyrene, and methylphenanthrenes/phenanthrene suggested the predominance of wood and coal combustion sources, the atmospheric deposition, and surface runoff to be the major transport pathways. A good correlation existed between the benzo[a]pyrene level and the total PAH concentrations, making this compound a potential molecular marker for PAH pollution. Total TEQ (S) (carc) values calculated for samples varied from 6.95 ng/g TEQ (S) (carc) to 119 ng/g TEQ (S) (carc) , with an average of 59 ng/g dry weight TEQ (S) (carc) . The baseline data can be used for regular monitoring, considering the industrial and agricultural growth around this coastal environment.

Trace metal bioaccumulation by soft-bottom polychaetes (Annelida) of Sundarban Mangrove Wetland, India and their potential use as contamination indicator.

Bioaccumulation of trace metals in four soft-bottom polychaetes along with the host sediments was recorded from the intertidal regions of Indian Sundarban mangrove wetland. The enrichment of Mn (maximum 730 mg kg⁻¹) and Zn (maximum 320 mg kg⁻¹) was recorded for all the polychaetes followed by Cr, Cu, As, Co, Ni and Pb, showing sharp variations between the species. However, concentrations of Sn and Hg were very low with small variations between the species. An overall high bioconcentration factor (BCF) was recorded in the capitellid worm Mastobranchus indicus. The results of the investigation indicate the possibility of developing a standard test protocol for bioaccumulation by polychaetous annelids.

Differential mRNA expression of acetylcholinesterase in the central nervous system of rats with acute and chronic exposure of sarin & physostigmine.

A time-course study was carried out to measure the acetylcholinesterase (AChE) gene expression in the brain of female rats exposed to different doses of sarin and physostigmine. Short-term effects were studied with an acute single subcutaneous dose (s.c.) of 80 microg kg(-1) (0.5 x LD(50)) sarin. Cortex and cerebellum showed a significant decline in AChE mRNA expression at 2.5, 24 and 72 h. Biochemical studies showed that plasma butrylcholinesterase (BChE) and brain AChE activities were significantly decreased at 2.5 h, which came back to near control values by 24 h in both cases. For long-term chronic studies, three groups of female rats received daily doses of physostigmine (0.1 mg kg(-1) day(-1)) intramuscularly (i.m.), sarin (15 microg kg(-1) day(-1)) s.c. independently and a combined dose of physostigmine (i.m.) (0.1 mg kg(-1) day(-1)) followed by sarin (s.c.) (15 microg kg(-1) day(-1)) continuously for 30 days. Differential AChE mRNA levels in cortex and cerebellum of rat brain were observed after 30 days and after a lag period of another 30 days with no further administration. Plasma (BChE) and brain (AChE) showed irregular inhibition profile in biochemical studies at 30 days and returned to control levels after 60 days. The acute single subcutaneous administration of sarin for short-term as well as chronic long-term studies showed that AChE inhibition alone does not lead to observed changes in mRNA expression of AChE gene. These observations further suggest that route of administration as well as dose exposure regimen also contributes to the regulation of AChE mRNA expression.

Role of inflammatory cytokines and DNA damage repair proteins in sulfur mustard exposed mice liver.

Sulfur mustard (bis-(2-chloroethyl) sulfide) is an alkylating agent, and produces blisters on skin and causes systemic toxicity and DNA strand breaks. The mechanism and role of inflammatory cytokines, receptors, and DNA damage signaling pathway specific genes were studied in sulfur mustard (SM) exposed mouse liver. Female mice were exposed percutaneously with 1.0 L.D50 of SM (8.1 mg/kg body weight). Inflammatory cytokine gene expression profiles were determined at 1 and 3 days post-exposure to SM and DNA damage signaling pathway specific, double strand break repair proteins gene expression profile at 1, 3, and 7 days were examined by DNA microarrays and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Anti-inflammatory cytokines and receptors were down-regulated from day 1 to day 3. Pro-inflammatory genes TNF-alpha, TNF receptors were up-regulated from day 1 to day 3. Double strand DNA break repair proteins Rad23, Rad50, Rad51, Rad52, and Rad54l were down-regulated from day 1 to day 7. This result indicates sulfur mustard causes inflammatory response, activates the cascade of events in the signal transduction pathway, and promotes irreversible double strand DNA breaks in chromosomal DNA, which is leading to cell death.

Adenosine deaminase estimation and multiplex polymerase chain reaction in diagnosis of extra-pulmonary tuberculosis.

SETTING: Extra-pulmonary tuberculosis (EPTB), including mycobacteriosis, contributes 15-20% of all tuberculosis (TB) cases. The diagnosis of EPTB remains elusive because of the inadequate sensitivity of routine and conventional bacteriological methods for the detection of Mycobacterium tuberculosis and related organisms in clinical specimens such as cerebrospinal fluid (CSF), pleural fluid and peritoneal fluid. OBJECTIVE: To develop a better diagnostic marker for EPTB. DESIGN: In our study, 179 cases of EPTB were analysed for acid-fast bacilli (AFB) smear, adenosine deaminase activity (ADA) and multiplex polymerase chain reaction (PCR). Although estimation of ADA is helpful, its sensitivity and specificity varies widely. On the other hand, a multiplex PCR using amplicons such as IS6110, dnaJ gene and hsp65 genes has high sensitivity (60-88%) and specificity (81-100%). RESULTS: On comparing AFB and ADA results with PCR, the PCR is clearly more effective than AFB (P < 0.001) and ADA estimation (P < 0.02) in CSF. The same result was observed with peritoneal fluid (P < 0.001 vs. P < 0.05) and pleural fluid (P < 0.001 and P < 0.05). CONCLUSION: The study shows that multiplex PCR remains the best tool and is a much better marker for diagnosing EPTB.

Occurrence, distribution and possible sources of organochlorine pesticide residues in tropical coastal environment of India: an overview.

Organochlorine pesticides (OCPs) are an important potential component of chemical pollutants used extensively for agriculture and sanitation purposes in India as these are comparatively cheap and effective. These persistent organic compounds such as HCH isomers, DDT and its metabolites are the predominant chemical contaminants found along the Indian coast and thus constitute both alluring and grave areas of scientific research. Our objective in the paper is to provide a comprehensive account of the distribution of organochlorine pesticides in biotic and abiotic compartments of the Indian coastal environment, make some comments on their environmental sources, their movement through the food chain and possible ecotoxicological risk of health in biota including humans. The prevalent HCH, DDT and HCB concentrations differ markedly in eastern and western coast of India reflecting differing agricultural and other usage and their ultimate input into the coastal environment by several rivers and the bioturbation activities of macrozoobenthos (bivalve mollusks, polychaetous annelids, etc.). In several cases, the DDT levels exceeded the effects range-low (ER-L) and could thus cause acute biological impairments, in comparison with the sediment quality guidelines. Contributions of DDT metabolites (DDT, DDD and DDE residues) vary in different Indian coastal regions predominated by pp'-DDT and pp'-DDD. Measured concentrations of HCHs were lower than DDTs that might be due to higher water solubility, vapor pressure and biodegradability of the latter. HCH and DDT residues in fish in India were lower than those in the temperate countries indicating a lower accumulation in tropical fish, which might be related to rapid volatilization of this insecticide in the tropical environment. The concentrations of other chlorinated pesticides (aldrin, dieldrin, eldrin, methoxychlor, endosulfan sulphate) were lower and not generally of great concern.

Organochlorine pesticide residues in sediment cores of sunderban wetland, northeastern part of Bay of Bengal, India, and their ecotoxicological significance.

This paper presents the first comprehensive report of the organochlorine pesticide residues (OCs) such as hexachlorocyclohexane isomers (HCHs), dichlorodiphenyltrichloroethane and its six metabolites (DDTs), and hexachlorobenzene (HCB) in core sediments (<63-microm particle size) from the Indian Sunderban wetland. The pooled mean values of the mass fraction of SigmaHCHs, HCB, and SigmaDDTs in the sediments were 0.05-12, 0.05-1.4, and 0.05-11.5 ng g(-1) dry weight, respectively. The vertical distribution of pesticides reveals an erratic pattern. The concentration of four isomers of HCHs reveals a heterogenic distribution where gamma-HCH (lindane) and beta-HCH shared the dominant part. The mass fraction of HCB did not show any sharp spatial variation. The prevailing sequence of DDT metabolites indicates an active degradation of the parent compound in the sediments and/or inputs of already degraded pp'DDT to the region. Peak concentrations of HCH isomers and DDT metabolites have the potential to induce ecotoxicological impact as per the sediment quality guidelines.

Liquorice and soy sauce, a life-saving concoction in a patient with Addison's disease.

Addison's disease is a relatively common disorder to endocrinologists, but is rare and potentially fatal when presenting acutely. Treatment now involves replacement of glucocorticoids and mineralocorticoids with synthetic compounds, although historically patients took common salt and plant-based preparations. We describe the case of a 42-year-old woman who self-treated undiagnosed Addison's disease for several years with soy sauce and liquorice sticks. She presented with a four-week history of decreased energy, malaise and postural dizziness. Our patient described an unusual diet of liquorice sticks and soy sauce, consuming around 46 g of salt per week. There was a family history of Type 1 diabetes mellitus. Physical examination was unremarkable, although subsequent investigation confirmed Addison's disease. Liquorice provided glycyrrhizic acid and glycyrrhetinic acid, which act on 11-beta hydroxysteroid dehydrogenase enzymes. In this case, the net effect was potentiation of glucocorticoid action on renal mineralocorticoid receptors in the context of failing adrenocortical steroid production. The case highlights the importance of taking a dietary history to aid diagnosis.

Distribution and possible source of trace elements in the sediment cores of a tropical macrotidal estuary and their ecotoxicological significance.

The paper presents the first document regarding concentration, distribution and possible sources of selected trace elements (Cu, Fe, Mn, Zn, Cr, Co, Ni, Pb, Al, B and Ba) in core sediments (<63 micro particle size) from the lower stretch of Hugli (Ganges) estuary, northeast coast of Bay of Bengal by ICP-AES and EDXRF to evaluate geochemical processes influencing their distribution and possible environmental consequences. The levels of elements showed a wide range of variations in different core depths, in upper and lower intertidal zones as well as among three sampling stations. The most interesting feature of the study is the downward increase of concentrations of majority of the elements reaching overall maximum values at a depth of 20-28 cm in upper littoral zone of the site located in the extreme downstream stretch of the estuary. Values of organic carbon showed very strong positive correlations with most of the elements as revealed by correlation matrix (r) values. The interelemental relationship revealed the identical behavior of element during its transport in the estuarine environment. The overall variation in concentration can be attributed to differential discharge of untreated effluents originating from industrial, agricultural, and aquacultural sources as well as from domestic sewage along with the fishing and boating activities. The resulting compositional dataset was tested by principal component analyses and cluster analyses. Pollution load index (PLI) and index of Geoaccumulation (Igeo) revealed overall low values but the enrichment factors (EFs) for Pb were typically high for all the stations. The mean concentrations of Zn and to some extent Cu exceeded the Effects Range-Low (ER-L) values in the majority of the cases indicating that there may be some ecotoxicological risk to organisms living in sediments. The concentration of the trace elements reported in this work is useful as baselines for comparison in future sediment quality studies.

Magnetic Resonance Imaging and the Use in Small Renal Masses.

The incidence of small renal masses (SRM) has been increasing, and this is mainly attributed to the incidental finding of such masses on imaging performed in asymptomatic patients. Consequently, this calls for careful evaluation and management of these masses to determine their nature and need for treatment. This article reviews current literature regarding the evaluation and management of SRM. It focuses on the specific use of MRI in the diagnosis and management of SRM. A Medline review of the literature was performed from 1996 to the present time. Computed tomography (CT) imaging has been the investigation of choice for evaluating SRM. However, some remain difficult to determine their malignant or benign nature and remain indeterminate. In such cases, further imaging with magnetic resonance imaging (MRI) can be performed to evaluate the mass in more detail. It can also be used where CT is contraindicated and where active surveillance is the treatment of choice and radiation exposure is a concern. MRI is a useful tool in evaluating an indeterminate small renal mass. Accurate diagnosis and management of SRM require close collaboration between a urologist and radiologist to identify potentially malignant tumours to subsequently reduce mortality from renal cell cancer.

Most commercial insulin assays fail to detect recombinant insulin analogues.

Insulin assays are utilized in various clinical scenarios, including the assessment of insulin therapy compliance or of suspected insulin overdose. In an interpretative exercise carried out by UK National External Quality Assessment Service (NEQAS), serum sent to the participating laboratories was spiked with 30 pmol/L of the short-acting insulin analogue Human Actrapid. Only two out of 24 participant laboratories had sufficient assay cross-reactivity with Actrapid to interpret the results as suggestive of insulin administration. The development of specific insulin assays has led to deterioration in the ability to detect non-compliance or overdose with recombinant insulin treatment. Clinicians should be aware of this significant limitation, which could lead to misdiagnosis.

Interspecific variation in heavy metal body concentrations in biota of Sunderban mangrove wetland, northeast India.

The coastal environment of West Bengal, recognized as the most diversified and productive ecosystem among all the maritime states of India, faces organic pollution from domestic sewage and urban and industrial effluents leading serious impacts on biota. The present paper aims at providing information on concentration level of heavy metals among the tissues of benthic polychaetes, bivalve molluscs and finfishes collected from Sundarban mangrove wetland, northeast coast of India. An overall common trend in bioaccumulation was revealed with the following decreasing order: Zn>Mn>Cu>Cr>Se>Hg with few exceptions. Both species dependent variability and temporal variations were pronounced. A high degree of organ specificity was evident in the bivalves where gill and mantle exhibited higher metal accumulation due to ion exchange property of the mucous layer covering these organs. Variability between closely related species is a reflection of different uptake rates, physiology and impact of environmental factors. The results of this analysis suggest that mollusks can play a significant role in trace metal trophic transfer studies, especially as their representatives are intertidally and subtidally ubiquitous.

Machine learning in soil classification.

In a number of engineering problems, e.g. in geotechnics, petroleum engineering, etc. intervals of measured series data (signals) are to be attributed a class maintaining the constraint of contiguity and standard classification methods could be inadequate. Classification in this case needs involvement of an expert who observes the magnitude and trends of the signals in addition to any a priori information that might be available. In this paper, an approach for automating this classification procedure is presented. Firstly, a segmentation algorithm is developed and applied to segment the measured signals. Secondly, the salient features of these segments are extracted using boundary energy method. Based on the measured data and extracted features to assign classes to the segments classifiers are built; they employ Decision Trees, ANN and Support Vector Machines. The methodology was tested in classifying sub-surface soil using measured data from Cone Penetration Testing and satisfactory results were obtained.