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Urban areas play a significant role in generating microplastics (MPs) through increased vehicular and human activities, making urban runoff a key source of MP pollution in receiving waterways. The composition of MPs is anticipated to vary with land use; hence, identifying the hotspots of contamination within urban areas is imperative for the targeted interventions to reduce MPs at their sources. This study collected one-liter stormwater runoffs from three different land uses as sheet flow during two storm events to quantify the MPs and identify the polymers transported from land-based sources. The analytical method included a combination of Fourier transform infrared spectrometer, Raman microscope, and Nile red staining techniques. This study analyzed the broad spectrum of MPs, i.e., 1 μm-5 mm, and tire wear and bitumen particles, considered the two major research gaps in stormwater studies. The MP concentrations were 67.7 ± 11.3 pL -1 in commercial, 23 ± 10.3 pL -1 in residential, and 168.7 ± 37.1 pL -1 in highways. The trend of MP concentrations followed an order of highway > commercial > residential with an exclusive presence of polymethylmethacrylate and ethylene-vinyl acetate in highways; cellophane, methylcellulose, polystyrene, polyamide, and polytetrafluorethylene in commercial; and high-density polyethylene in residential areas. The dominant MP morphology consisted of fragments, accounting for 89 % of the identified MPs, followed by 10 % fibers and 1 % films. This study observed a prevalence of MPs sizes <125 μm constituting 49 % of the total composition. These findings underscore the vital role of land use patterns in shaping MP abundance and reinforce the urgency of implementing effective management strategies to mitigate MP pollution in stormwater runoff., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Chronic low back pain (CLBP) is a persistent and debilitating condition characterized by pain and discomfort in the lower back region that lasts more than 12 weeks. This review aims to determine the efficacy and safety of various doses of tanezumab for managing CLBP. The present meta-analysis was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and the Cochrane Handbook for Systematic Reviews of Intervention standards. We searched multiple databases, including PubMed, Cochrane Library, Excerpta Medica Database (EMBASE), Scopus, and Web of Science, to identify randomized controlled trials comparing tanezumab to placebo or different dosage regimens for CLBP in adult patients. The primary outcome was the mean change in low back pain intensity (LBPI) score baseline to the end of treatment. Secondary outcomes included adverse events and the degree of disability or impairment. A total of six studies were included in the meta-analysis. Analysis of the data showed that tanezumab 5 mg significantly reduced LBPI compared to placebo at all time points (mean deviation (MD) ranging from -0.31 to -0.5). Similarly, tanezumab 10 mg showed a significant reduction in LBPI compared to placebo at all time points (MD ranging from -0.48 to -0.84). However, tanezumab 5 mg showed significantly less reduction of LBPI compared to 10 mg at two, four, eight, and 12 weeks (MD ranging from 0.19 to 0.32). These findings suggest that tanezumab is an effective treatment for CLBP, with 5 mg and 10 mg doses providing clinically meaningful reductions in LBPI., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Tahir et al.)

There has been a growing number of nutrition data visualization tools (DVTs) to monitor progress towards targets and encourage action. However, there are few documented examples of how to go about designing effective DVTs for nutrition-related audiences. In this Open Letter, we summarize reflections from collaborative efforts between the Nigeria Governors' Forum (NGF) and the Data for Decisions to Expand Nutrition Transformation project (DataDENT) in 2019-2021 to design a sub-national nutrition scorecard that aims to hold Nigeria's 36 Governors accountable to nutrition commitments. Our reflections add to an emerging body of work advocating for DVT design processes to develop a specific theory of change for how the DVT will influence target groups and achieve aims. Once the target audience is identified, it is important to create a strong engagement strategy to ensure that the DVT promotes constructive action. We also highlight the importance of identifying actionable indicators through participatory processes. We hope that these insights about collaborative DVT design can be applied by countries and institutions who want to develop similar tools to advance the nutrition agenda in their context., Competing Interests: No competing interests were disclosed., (Copyright: © 2021 Rana Y et al.)

This study was carried out to investigate the risks of simultaneous exposure to pesticide residues and bacteria contaminants in locally produced fresh vegetables and vegetables in Tanzania. A total of 613 samples were analyzed for pesticide residues, out of which 250 were also analyzed for bacterial contamination. Overall, 47.5% had pesticide residues, 74.2% exceeded Maximum Residue Levels (MRLs). Organophosphorus (95.2%), organochlorines (24.0%), pyrethroids (17.3%), and carbamates (9.2%) residues dominated. MRL values were mostly exceeded in tomatoes, onions, watermelons, cucumbers, Chinese cabbage, and sweet paper. Tetramethrin (0.0329-1.3733 mg/kg), pirimiphos-methyl (0.0003-1.4093 mg/kg), permethrin (0.0009-2.4537 mg/kg), endosulfan (beta) (0.0008-2.3416 mg/kg), carbaryl (0.0215-1.5068 mg/kg), profenofos (0.0176-2.1377 mg/kg), chlorpyrifos (0.0004-1.2549 mg/kg) and dieldrin (0.0011-0.5271 mg/kg) exceeded MRLs. The prevalence of bacteria contamination was high (63.2%). Enterobacter (55.6%) Pseudomonas aeruginosa (32.4%), E. coli (28.2%), Citrobacter (26.8%), Klebsiella oxytoca (14.8%), and Salmonella (7.7%) were isolated. Furthermore, 46.4% tested positive for both pesticide residues and bacterial contaminants. Vegetables from farms (60.7%) contained more dual contaminants than market-based vegetables (41.8%). This may have resulted from excessive pesticide use and unhygienic handling of fresh fruits and vegetables at production level. Binary logistic regression showed that fresh fruits and vegetables with pesticide residues were 2.231 times more likely to have bacteria contaminants (OR: 2.231; 95% CI: 0.501, 8.802). The contamination levels of pesticide residues and bacterial contaminants could be perceived as a serious problem as most fresh fruits and vegetables recorded values of pesticide residues far above the MRLs with pathogenic bacteria isolated in higher proportions. MRLs was higher in most vegetables consumed raw or semi-cooked such as watermelons, carrots, cucumber, tomatoes, onion and sweet paper. There is an urgent need to develop pesticide monitoring and surveillance systems at farmer level, educating farmers and promoting the use of greener pesticides to mitigate the health effects of pesticides and bacterial contaminants., Competing Interests: The authors have declared that no competing interests exist.

Biomonitoring of pesticides exposure has currently become a matter of great public concern due to the potential health effects of pesticides. This study assessed levels of acetylcholinesterase (AChE) inhibition and associated health effects in uncontrolled smallholder farming systems in rural Tanzania. A cross-sectional study was conducted of 90 exposed farmers and 61 nonexposed controls from horticultural zones. A structured questionnaire was administered, and a capillary blood sample of 10  μ l was used to measure AChE activity using an Erythrocyte Acetylcholinesterase Test Mate Photometric Analyzer kit (Model 400). A multiple logistic regression model was used to investigate determinants of pesticide exposure. The study revealed that smallholder farmers are occupationally exposed to pesticides. Exposed farmers had significantly lower AChE levels. The use of personal protective equipment (PPE) did not significantly reduce the likelihood of AChE inhibition. Women, younger and older farmers, and underweight, overweight, and obese farmers were at increased risk of AChE inhibition. Increase in age (10 years) increased likelihood of AChE inhibition by 6.7%, while decrease in BMI increased likelihood of AChE inhibition by 86.7% while increased pesticides contact hours increased risk of having lower AChE at about 3 times. The number of exposure symptoms (14.10 ± 7.70) was higher in exposed farmers than unexposed. Self-reported symptoms are confirmed to correlate to lower AChE. Prevalence of tiredness (71.6% against 15.5%), fatigue (64.8% against 27.6%), soreness in joints (59.1% against 20.7%), thirst (52.3% against 12.1%), skin irritation (52.1% against 17.2%), salivation and abdominal pain (50% against 8.6% and 31.0%, respectively), muscle weakness (47.7% against 24.1%), and memory loss (47.7% against and 29.3%) differed significantly between exposed and control. This study provides useful information regarding the level of occupational and environmental exposure to pesticides in smallholder horticultural production systems. Pesticides use needs to be controlled at farm level by developing pesticides monitoring and surveillance systems., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this paper., (Copyright © 2019 Jones A. Kapeleka et al.)

Abstract: In this study, the effect of urbanization and environmental pollution on qualitative (structural) and quantitative changes of the Corylus avellana (hazel) pollen was investigated using scanning electron microscopy, Fourier Transform Infrared (FTIR) spectroscopy and curve-fitting analysis of amide I profile. The obtained spectroscopic results show significant variations in the fraction of proteins in the hazel pollen, which probably depend on various degrees of anthropopression. Our results suggest that alterations in the chemical composition of pollen, induced by urbanization and air pollutants, may intensify the allergenic potential and may cause the increase in the incidence of allergies in people. Mutations in nucleic acids are accompanied by a number of molecular changes leading to the formation of allergenic proteins. It seems that the type of habitat, where the pollen grew, affects the individual differentiation. Indeed, it was found that in the site exhibiting low pollution, the hazel pollen contain a lower amount of proteins than to the ones from a site with high anthropopression. Hence, FTIR spectroscopy and curve-fitting analysis of amide I profile can be successfully applied as tools for identifying quantitative and qualitative changes of proteins in hazel pollen., Graphical Abstract: Anthropogenic factors such as air pollution and urbanization lead to changes in structure and chemical composition of hazel pollen. Fourier Transform Infrared spectroscopy (FTIR) and Gaussian analysis showed structural changes in hazel pollen collected from sites with different absorbance values of individual chemical functional groups and changes in the secondary structure of proteins of the pollen.

Green synthesis method using camomile extract was applied to synthesize silver nanoparticles to tune their antibacterial properties merging the synergistic effect of camomile and Ag. Scanning transmission electron microscopy revealed that camomile extract (CE) consisted of porous globular nanometer sized structures, which were a perfect support for Ag nanoparticles. The Ag nanoparticles synthesized with the camomile extract (AgNPs/CE) of 7 nm average sizes, were uniformly distributed on the CE support, contrary to the pure Ag nanoparticles synthesized with glucose (AgNPs/G), which were over 50 nm in diameter and strongly agglomerated. The energy dispersive X-ray spectroscopy chemical analysis showed that camomile terpenoids act as a capping and reducing agent being adsorbed on the surface of AgNPs/CE enabling their reduction from Ag(+) and preventing them from agglomeration. Fourier transform infrared and ultraviolet-visible spectroscopy measurements confirmed these findings, as the spectra of AgNPs/CE, compared to pure CE, did not contain the 1109 cm(-1) band, corresponding to -C-O groups of terpenoids and the peaks at 280 and 320 nm, respectively. Antibacterial tests using four bacteria strains showed that the AgNPs/CE performed five times better compared to CE AgNPs/G samples, reducing totally all the bacteria in 2 h.

We hereby report the design and implementation of an Autonomous Microbial Cell Culture and Classification (AMC(3)) system for rapid detection of food pathogens. Traditional food testing methods require multistep procedures and long incubation period, and are thus prone to human error. AMC(3) introduces a "one click approach" to the detection and classification of pathogenic bacteria. Once the cultured materials are prepared, all operations are automatic. AMC(3) is an integrated sensor array platform in a microbial fuel cell system composed of a multi-potentiostat, an automated data collection system (Python program, Yocto Maxi-coupler electromechanical relay module) and a powerful classification program. The classification scheme consists of Probabilistic Neural Network (PNN), Support Vector Machines (SVM) and General Regression Neural Network (GRNN) oracle-based system. Differential Pulse Voltammetry (DPV) is performed on standard samples or unknown samples. Then, using preset feature extractions and quality control, accepted data are analyzed by the intelligent classification system. In a typical use, thirty-two extracted features were analyzed to correctly classify the following pathogens: Escherichia coli ATCC#25922, Escherichia coli ATCC#11775, and Staphylococcus epidermidis ATCC#12228. 85.4% accuracy range was recorded for unknown samples, and within a shorter time period than the industry standard of 24 hours.

Background: We describe the development of an electrochemical sensor array for monitoring the proliferation effects of cissus populnea plant extracts on TM4 Sertoli cells., Methods: The proliferation activities of the extracts on Sertoli cells were studied using a high-throughput electrochemical sensor array (DOX-96) and the analytical sensor characteristics were compared with conventional colorimetric MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and fluorescence spectroscopy., Results: This work shows that there is a definite positive trend in the proliferation effect of the extract of Cissus populnea on the TM4 Sertoli cells. All of the three techniques confirmed that the most effective concentration for the proliferation is 10 ppm. At this concentration, the proliferation effect was established around 120% for both DOX-96 and MTT techniques, whereas fluorescence assays showed a higher level (120-150%). DOX-96 showed a lower limit of detection (1.25 × 10(4) cells/ml); whereas the LOD recorded for both MTT and fluorescence techniques was 2.5 × 10(4) cells/ml. Visual examination of the cells by means of confocal fluorescence microscopy confirmed the proliferation of Sertoli cells as was determined using the MTT assay. This investigation provides a confident interpretation of the results and proved that the most effective concentration for the proliferation using Cissus populnea plant extract is 10 ppm., Conclusions: Overall, the DOX results compared well with the conventional methods of checking proliferation of cells. The fascinating feature of the sensor array is the ability to provide continuous proliferation experiments with no additional reagents including 96 simultaneous electrochemical experiments. The use of the DOX-96 could reduce a typical bioassay time by 20-fold. Thus the DOX-96 can be used as both a research tool and for practical cell culture monitoring.

The discovery of fullerenes in 1985 has ushered in an explosive growth in the applications of engineered nanomaterials and consumer products. Nanotechnology and engineered nanomaterials (ENMs) are being incorporated into a range of commercial products such as consumer electronics, cosmetics, imaging and sensors. Nanomaterials offer new possibilities for the development of novel sensing and monitoring technologies. Nanosensors can be classified under two main categories: (i) Nanotechnology-enabled sensors or sensors that are themselves nanoscale or have nanoscale materials or components, and (ii) Nanoproperty-quantifiable sensors or sensors that are used to measure nanoscale properties. The first category can eventually result in lower material cost, reduced weight and energy consumption. The second category can enhance our understanding of the potential toxic effects of emerging pollutants from nanomaterials including fullerenes, dendrimers, and carbon nanotubes. Despite the enormous literatures and reviews on Category I sensors, there are few sensors to measure nanoscale properties or sensors belonging to Category II. This class of nanosensors is an area of critical interest to nanotoxicology, detection and risk assessment, as well as for monitoring of environmental and/or biological exposure. This article discusses emerging fields of nanotoxicology and nanomonitoring including the challenges of characterizing engineered nanomaterials and the potentials of combining existing analytical techniques with conventional cytotoxicity methods. Two case studies are provided for development of Category II nanosensors for fullerene nanoparticles and quantum dots. One highlights the uniqueness of a portable, dissolved oxygen electrochemical sensor arrays capable of detecting the ENMs as well as provide rapid nanotoxicological information. This review has shown that addressing the complex and critical issues surrounding the environmental transformation and toxicity of ENMs must be accompanied by the creation of new approaches or further developments of existing instrumentation.

DNA biosensors are increasingly used in hybridization reactions, mutation detection, genomic sequencing, and identification of pathogens. However, the inability to monitor the recognition signals without resorting to the use of labels or electroactive mediators has led to DNA devices with inadequate sensitivity. Moreover, some electroactive species require high redox potentials that often destroy the DNA complementarity. This article presents the concept of metal-enhanced detection (MED) for the determination of DNA-DNA reactions and presents the application of this concept for mismatch detection. The MED concept relies on the idea that metallic films deposited as a continuous layer or monolayer onto a solid electrode, or even electrostatically held, could greatly enhance the rate of electron transfer by reducing the distance between the donor and acceptor species and could lead to label-free assays during DNA hybridization reactions. The MED concept has been tested for voltammetric detection of gene sequence of Microcystis spp. The resulting biosensor involved the immobilization of a 17-mer DNA probe that is complementary to a specific gene sequence of Microcystis spp. on a gold electrode via avidin-biotin chemistry. Electrochemical reduction and oxidation of DNA-captured Ag(+) ions provided the detection signals for the target gene sequence in solution. A linear response of silver cathodic peak current with concentration of the target oligonucleotide sequence was observed with a detection limit of 7 x 10(-9)M. This label-free approach was successfully applied to detecting two-base-pair mismatches in the gene sequence of Microcystis spp.

To date limited data exists that addresses the impact of urinary incontinence on sexual function. In the present study, we assessed sexual functions in patients with urinary incontinence and compared with healthy continent subjects by means of Female Sexual Function Index (FSFI) questionnaire. A total of 21 premenopausal incontinent women (three stress incontinence, nine overactive bladder and nine mixed incontinence) were enrolled in the study, and 18 healthy continent subjects served as controls. All subjects were asked to complete FSFI questionnaire and each FSFI domain scores including desire, arousal, lubrication, orgasm, satisfaction and pain were calculated. The mean scores in each domain were compared between the groups. Mean age of subjects with urinary incontinence and controls were 39.5+/-6.6 and 32.6+/-9.1 y, respectively. All domain scores were significantly lower in incontinent women except for pain. Among the incontinence types, no significant difference was determined in all domains of FSFI. Urinary incontinence significantly reduces sexual functions in premenopausal sexually active women.

Due to the increased threats of chemical and biological agents of injury by terrorist organizations, a significant effort is underway to develop tools that can be used to detect and effectively combat chemical and biochemical toxins. In addition to the right mix of policies and training of medical personnel on how to recognize symptoms of biochemical warfare agents, the major success in combating terrorism still lies in the prevention, early detection and the efficient and timely response using reliable analytical technologies and powerful therapies for minimizing the effects in the event of an attack. The public and regulatory agencies expect reliable methodologies and devices for public security. Today's systems are too bulky or slow to meet the "detect-to-warn" needs for first responders such as soldiers and medical personnel. This paper presents the challenges in monitoring technologies for warfare agents and other toxins. It provides an overview of how advances in environmental analytical methodologies could be adapted to design reliable sensors for public safety and environmental surveillance. The paths to designing sensors that meet the needs of today's measurement challenges are analyzed using examples of novel sensors, autonomous cell-based toxicity monitoring, 'Lab-on-a-Chip' devices and conventional environmental analytical techniques. Finally, in order to ensure that the public and legal authorities are provided with quality data to make informed decisions, guidelines are provided for assessing data quality and quality assurance using the United States Environmental Protection Agency (US-EPA) methodologies.

The need for rapid and accurate detection systems is expanding and the utilization of cross-reactive sensor arrays to detect chemical warfare agents in conjunction with novel computational techniques may prove to be a potential solution to this challenge. We have investigated the detection, prediction, and classification of various organophosphate (OP) nerve agent simulants using sensor arrays with a novel learning scheme known as support vector machines (SVMs). The OPs tested include parathion, malathion, dichlorvos, trichlorfon, paraoxon, and diazinon. A new data reduction software program was written in MATLAB V. 6.1 to extract steady-state and kinetic data from the sensor arrays. The program also creates training sets by mixing and randomly sorting any combination of data categories into both positive and negative cases. The resulting signals were fed into SVM software for "pairwise" and "one" vs all classification. Experimental results for this new paradigm show a significant increase in classification accuracy when compared to artificial neural networks (ANNs). Three kernels, the S2000, the polynomial, and the Gaussian radial basis function (RBF), were tested and compared to the ANN. The following measures of performance were considered in the pairwise classification: receiver operating curve (ROC) Az indices, specificities, and positive predictive values (PPVs). The ROC Az) values, specifities, and PPVs increases ranged from 5% to 25%, 108% to 204%, and 13% to 54%, respectively, in all OP pairs studied when compared to the ANN baseline. Dichlorvos, trichlorfon, and paraoxon were perfectly predicted. Positive prediction for malathion was 95%.

Metals and radionuclides are usually coupled with proteins together with suitable ligands for therapeutic, tumor-imaging, pharmaceuticals, and biocompatibility applications. Several ligands that can strongly coordinate a given nuclide in a specific valency are already known. However, the demand for bifunctionality has limited the applications of these ligands. We hereby report the molecular design of a receptor system based on the linkage of protein to monoazo ligands. By use of basic coordination chemistry, 4-(3-quinolinoazo)hydroxybenzoic acid (QABA) and derivatives were successfully conjugated to ovalbumin, bovine serum albumin, and alkaline phosphatase at a site that was distinct from the metal binding site. The presence of carboxylic acid linkage in the QABA served as a convenient bridge for protein conjugation and may allow the generic application of these ligands for bioconjugate synthesis while ensuring a high in vivo stability. The ligand-protein conjugates were characterized using UV-vis spectroscopy, Fourier transform infrared spectroscopy, thin layer chromatography, NMR, and surface-enhanced laser desorption ionization time-of-flight mass spectrometry. The conjugate was tested for the ability to recognize nonradioactive Ga(3+) at a physiological pH, and a binding constant of 1 x 10(20) was recorded. Also, the in vitro testing results indicated that the fluorescent conjugates exhibited significant selectivity for gallium compared to Pb(2+), Hg(2+), Zn(2+), Cu(2+), Fe(3+), and Co(2+) while no responses were obtained for alkaline and alkaline earth metals. These attributes could allow these conjugates to be used as a model for imaging sensors and for metal detection.

This work describes the theoretical and experimental approaches for monitoring the interfacial biomolecular reaction between immobilized antibody and the antigen binding partner using novel differential impedance spectroscopy. The prerequisite of any biosensor is the immobilization of macromolecules onto the surface of a transducer. It is clear that the function of most macromolecules changes from what is observed in solution once immobilization has occurred. In the worst case, molecules entirely lose their binding activity almost immediately after immobilization. Certain conditions (e.g., denaturation, interfacial effects based on ionic strength, surface charge, dielectric constants, etc.) at interfaces are responsible for alterations of binding activity; it is not clear whether a combination of such processes is understood. However, these processes in combination must be reliably modeled in order to predict the outcome for most macromolecules. This work presents the theoretical and practical means for elucidating the surface reactivity of biomolecular reagents using ion displacement model with antibody-antigen (Ab-Ag) reaction as the test case. The Ab-Ag reaction was directly monitored using a dual-channeled, impedance analyzer capable of 1 measurement/s using covalent immobilization chemistry and polymer-modified electrodes in the absence of a redox probe. The evidence of Ab-Ag binding was revealed through the evolution of differential admittance. The surface loading obtained using the covalent immobilization chemistry was 9.0 x 10(16)/cm2, whereas with polymer-modified electrodes, the surface loading was 9.0 x 10(15)/cm2, representing a 10 times increase in surface reactivity. The proposed approach may be applicable to monitoring other surface interfacial reactions such as DNA-DNA interactions, DNA-protein interactions, and DNA-small molecule interactions.

This work describes the results of a mechanistic investigation of antibody-antigen binding using electrochemical quartz crystal microbalance (EQCM). The aim was to verify the contribution of electrolytes to conducting polypyrrole electrodes that have been modified with proteins. The behavior of an EQCM film containing various counterions was studied (chloride, dodecylsulphate and proteins) and mass changes recorded in a series of anions, cations and proteins. Results obtained indicate that the interaction of different proteins at quartz crystal electrode surface is dependent on the applied potential, the nature of the cations and anions, and the specificity of the immobilized antibody. The resonant frequency of the anti-HSA-coated quartz abruptly decreased upon contact with the antigen and this stabilized within 5 min in the concentration range between 1 and 100 ppm. The injection of other proteins such as bovine serum albumin and chymotrypsin, yielded responses that were significantly lower in magnitude than those obtained for the corresponding HSA.

This work describes the chemistry and methodology for constructing multilayers of bis-biotinylated dsDNA on metal substrates after enzyme cleavage and demonstrates its use for amplified microgravimetric and impedimetric analyses of anticancer drug, cisplatin. Specific chemical modification of dsDNA prior to immobilization was achieved via a bisulfite-catalyzed transamination of cytosine after endonuclease cleavage of plasmid DNA. The specificity of the reaction of cytosine residues at ss- versus dsDNA loci after endonuclease cleavage was characterized using circular dichroism, mass spectrometry, and absorption spectrophotometry. The biotinylated dsDNA consisting of 2961 base pairs was then used as a ligand at avidin-modified gold electrodes. Ac impedance spectroscopy and quartz crystal microbalance measurements clearly showed that the response to cisplatin increased linearly with target concentrations. The impedance spectroscopy resulted in a detection limit of 1 nM and a surface density of 4.8 x 10(13) molecules/0.1 cm(2). The immobilization of dsDNA on surfaces is a significant improvement over existing approaches in that it enables the attachment of long pieces of unmodified double-stranded DNA via a simple biotinylation step. The immobilization technique provides a generic approach for dsDNA-based sensor development and for monitoring DNA-analyte interactions.

Supramolecular docking and immobilization of biotinylated dsDNA onto a self-assembled monolayer of avidin have been measured using impedance spectroscopy and quartz crystal microbalance technique. The formation of the serial assembly was first achieved by linearizing circular plasmid dsDNA using BamH I endonuclease enzyme. This was followed by a bisulfite-catalyzed transamination reaction in order to biotinylate the dsDNA. The reaction is single-strand specific, and it specifically targets unpaired cytosine bases generated during the enzyme cleavage. The biotinylated dsDNA was then used as a ligand at a gold electrode containing avidin. The process was monitored by ac impedance spectroscopy that was used to probe the changes in interfacial electron-transfer resistance upon binding and a microgravimetric quartz crystal microbalance that reflected in situ mass changes on the dsDNA-functionalized substrates. Our results demonstrated that this approach could be employed for the determination of small-molecular-weight organics such as cisplatin, daunomycin, bisphenol A, chlorinated phenols, and ethidium bromide. A detection limit in the magnitude of ca. 10 nM was achieved. This immobilization technique provides a generic approach for dsDNA-based sensor development and for the monitoring of DNA-analyte interactions.

The accurate determination of postmortem interval (PMI) using the formation of adipocere presents a significant challenge to forensic scientists interested in determining the time of death. Several attempts have been made to determine the time since the occurrence of death. However, up to date, this has been difficult because previous approaches have been mainly qualitative, focusing on the later stages of degradation processes. This work presents preliminary results of an experimental model of postmortem adipocere formation using liquid chromatography. Three pig cadavers were submerged in distilled water, chlorinated water, and saline water. Fresh specimens resulting from the degradation in the subcutaneous fat were obtained from the pigs at two-week intervals for a period of ten weeks, and were subjected to chromatographic analysis. By correlating the ratio of the disappearance of hydrolyzed fatty acids with the formation of hydroxystearic and oxostearic acids after death, a simple, quantitative analytical method was developed for the determination of PMI. Experimental observation of the chemistry of adipocere formation indicated that adipocere can be formed only a few hours after an incidence of death and this continues until the saturation of oleic acid degradation after several weeks. Different time courses were obtained for cadavers immersed in distilled, chlorinated, and saline water, respectively. This work has not in any way solved the time since death problem. But it may be an approach to the problem that has not been adequately explored.

The detection of gallium in biological samples is required due to its role in the diagnosis of tumor and for possible treatment of malignancies. However, the use of purely instrumental techniques is unsuitable for detection of low levels of gallium in biological matrixes. We have synthesized new protein conjugates based on 4-(2-pyridylazo) ligands. The conjugates were successfully employed for the detection of gallium in biological matrixes using a nonantibody-based sandwich assay format. The recovery level obtained was between 97 and 101.3 with a relative standard deviation of less than 5%. The assay resulted in a detection limit of 5 x 10(-8) M and a remarkable selectivity for gallium(III) relative to other metals investigated. The new method provided adequate accuracy for gallium applicable for animal physiology and clinical toxicology.

Novel strategies are providing a more comprehensive and refined basis for understanding the occurrence and effects of endocrine disrupters.

This paper discusses basic electrochemical immunoassay technology. Factors limiting the practical application of antibodies to analytical problems are also presented. It addresses the potential use of immunoassay methods based on electrochemical detection for the analysis of environmental samples. It provides examples for the detection and quantitation of environmental samples using conducting electroactive polymers (CEPs). CEP-based immunosensing systems are compared with conventional environmental immunoassay procedures. The advantages of using these types of sensors for rapid, sensitive, and cost-effective analysis of pesticides and toxic chemicals are analysed and discussed. CEP-based immunosensing technology might eventually be used for continuous monitoring of effluents such as waste streams to determine compliance with regulations. CEP-based sensors are suitable for monitoring ground-water, waste stream effluents, agricultural run-offs and for monitoring the effectiveness of remediation, or for other situations where a real-time monitoring capability is desired.