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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.11.012 Byline: Claudio Escobar (a), Cesar Soto-Salazar (b), M. Ines Toral (a) Keywords: Electrocoagulation; Copper; Lead and cadmium removal; Optimization conditions for electrocoagulation Abstract: Chemical, electrochemical and flow variables were optimized to examine the effectiveness of the electrocoagulation process for the removal of copper, lead and cadmium. The electrochemical process, which uses electrodes of commercial laminate steel, was applied to simulated wastewater containing 12mgdm.sup.-3 of copper, 4mgdm.sup.-3 of lead and 4mgdm.sup.-3 of cadmium. The optimum conditions for the process were identified as pH=7, flow rate=6.3cm.sup.3 min.sup.-1 and a current density between 31 and 54Am.sup.-2. When the electrode geometric area and time of electrolysis reached critical values, the copper removal reached a maximum value of 80%. A linear relationship was identified between the current density and the mass of generated sludge. In addition, a linear relationship was found between specific energy consumption and current density. The results of this investigation provide important data for the development of an industrial-scale electrolytic reactor. Author Affiliation: (a) Laboratory of Analytical Chemistry, Department of Chemistry, Faculty of Sciences, University of Chile, Las Palmeras 3425, P.O. Box 653, Santiago, Chile (b) Department of Analytical and Inorganic Chemistry, Faculty of Chemical Sciences, University of Concepcion, P.O. Box 160C, Concepcion Edmundo Larenas 129, Concepcion, Chile Article History: Received 10 December 2004; Revised 4 November 2005; Accepted 10 November 2005

A derivative spectrofluorimetric method for simultaneous determination of enrofloxacin (EFX) and ciprofloxacin (CFX) in cow milk was developed. The sample preparation was based on rotating disk sorptive extraction (RDSE) using Oasis HLB® as extraction phase and followed by desorption of the analytes with methanol. The final extracts were evaluated by derivative spectrofluorimetry. An analyte-free cow milk was used as blank sample which was spiked with a known amount of analytes for the study of variables. The sample was treated with trichloroacetic acid in order to precipitate proteins. Furthermore, the extraction was carried out in the presence of Mc Ilvaine-EDTA 0.3M buffer to avoid any type of interference from the calcium ion. The variables involved in the RDSE process were pH and extraction time. Spectral variables were also optimized and analytical signals were evaluated at 417nm and 438nm for EFX and CFX, respectively. The limit of detection (LOD) and limit of quantification (LOQ) were 2.98 - 9.04 µg ⋅ L-1 and 2.56 - 7.75 µg ⋅ L-1, for EFX and CFX respectively. The precision levels, expressed as relative standard deviation, for EFX and CFX were 3.2% and 3.0%, respectively. The recoveries were between 98.8% to 100.5%. Commercial milks were analyzed and both antibiotics shown concentrations below to LOD in the batches analyzed. Finally, the proposed method offers advantages in terms of simplicity, efficiency and cost. Besides being friendly with the environment. [ABSTRACT FROM AUTHOR]

Abstract Background The Himalayas have always been an enigma and, being biodiversity hotspots, are considered extremely important from an ecological point of view. Recent advances in studies regarding high-altitude lakes have garnered relevant importance as these habitats could harbor potential psychrophilic and psychrotrophic microbes with bio-prospective applications. Contemplating the above scenario, the present study has been undertaken to understand the diversity and the functional capacities of the microbes thriving in this lake. Results In our present study on Samiti Lake, the abundance of Proteobacteria as the major phylum was seen in both the soil and water samples. Incase of the ABSLW (water) and ABS1 (soil) sample, 148,066 and 239,754 predicted genes, were taken for functional analysis. The KEGG analysis showed that ABSLW and ABS1 had 122,911 and 160,268, genes assigned to KO terms respectively. Whereas in case of COG functional analysis, 104,334 and 130,191 genes were assigned to different COG classes for ABSLW and ABS1 respectively. Further, on studying the glycoside hydrolases, an abundance of GH13, GH2, GH3, GH43, and GH23 in both the soil and water samples were seen. Conclusion Our study has provided a comprehensive report about the bacterial diversity and functional capacities of microbes thriving in Samiti Lake. It has also thrown some light on the occurrence of glycoside hydrolases in this region, as they have numerous biotechnological applications in different sectors.

Chemotherapy and radiotherapy resistance are major obstacles in the long-term efficacy of head and neck squamous cell carcinoma (HNSCC) treatment. Secondhand smoke (SHS) exposure is common and has been proposed as an independent predictor of HNSCC recurrence and disease-free survival. However, the underlying mechanisms responsible for these negative patient outcomes are unknown. To assess the effects of SHS exposure on cisplatin efficacy in cancer cells, three distinct HNSCC cell lines were exposed to sidestream (SS) smoke, the main component of SHS, at concentrations mimicking the nicotine level seen in passive smokers’ saliva and treated with cisplatin (0.01–100 µM) for 48 h. Compared to cisplatin treatment alone, cancer cells exposed to both cisplatin and SS smoke extract showed significantly lower cisplatin-induced cell death and higher cell viability, IC50, and indefinite survival capacity. However, SS smoke extract exposure alone did not change cancer cell viability, cell death, or cell proliferation compared to unexposed control cancer cells. Mechanistically, exposure to SS smoke extract significantly reduced the expression of cisplatin influx transporter CTR1, and increased the expression of multidrug-resistant proteins ABCG2 and ATP7A. Our study is the first to document that exposure to SHS can increase cisplatin resistance by altering the expression of several proteins involved in multidrug resistance, thus increasing the cells’ capability to evade cisplatin-induced cell death. These findings emphasize the urgent need for clinicians to consider the potential role of SHS on treatment outcomes and to advise cancer patients and caregivers on the potential benefits of avoiding SHS exposure.

ObjectivesE-cigarettes pose significant risks to youth, but smokers may benefit from switching to e-cigarettes by reducing their exposure to toxicants, which creates a challenge for the Food and Drug Administration (FDA) in regulating e-cigarettes to protect population health. This study aims to develop e-liquid product standards for nicotine form and concentration that reduce the appeal of e-cigarettes to young people while keeping e-cigarettes available as a safer alternative for smokers.Design and participantsA single-visit, double-blinded, randomized crossover design will be used to examine the effects of e-liquids with varying fractions of free-base nicotine (5%, 25%, 45%, 65%, 85%) among a sample of 66 young adult EC users and 66 older adult smokers, across ecologically valid total nicotine concentrations (20 mg or 50 mg/mL).Interventions and outcomesA 2-puff session will be conducted to test each of the 10 e-liquids in randomly assigned sequences, followed by a 10-minute washout period and participant ratings on appeal and sensory attributes such as throat hit and harshness, as well as behavioral intentions for continued use. Generalized linear mixed models will be used to determine a free-base nicotine level that has limited or no appeal to young adult e-cigarette users while remaining acceptable to smokers.ConclusionsThis study will provide the FDA with scientific evidence regarding the effect of product standards that mandate a minimum threshold for the fraction of free-base nicotine.Trial registrationThe study is registered on clinicaltrials.gov under the identifier NCT05864586.

Abstract Tobacco smoking is the leading preventable cause of cancer. Moreover, continued smoking during cancer therapy reduces overall survival. Aware of the negative consequences of tobacco smoking and the challenges of smoking cessation, cancer patients are inquiring whether they should switch to electronic cigarettes (e-cigarettes). To obtain evidence-based data to inform this decision, we examined the effects of e-cigarette aerosol exposure on cisplatin resistance in head and neck cancer cells. Our results show that cancer cells exposed to e-cigarette aerosol extracts and treated with cisplatin have a significant decrease in cell death, increase in viability, and increase in clonogenic survival when compared to non-exposed cells. Moreover, exposure to e-cigarette aerosol extracts increased the concentration of cisplatin needed to induce a 50% reduction in cell growth (IC50) in a nicotine-independent manner. Tobacco smoke extracts induced similar increases in cisplatin resistance. Changes in the expression of drug influx and efflux transporters, rather than activation of cell growth-promoting pathways or DNA damage repair, contribute to e-cigarette induced cisplatin resistance. These results suggest that like combustible tobacco, e-cigarette use might increase chemotherapy resistance, and emphasize the urgent need for rigorous evaluation of e-cigarettes health effects to ensure evidence-based public health policies.

Amorolfine (AOF) is a compound with fungicide activity based on the dual inhibition of growth of the fungal cell membrane, the biosynthesis and accumulation of sterols, and the reduction of ergosterol. In this work a sensitive kinetic and spectrophotometric method for the AOF quantitation based on the AOF oxidation by means of KMnO4 at 30 min (fixed time), pH alkaline, and ionic strength controlled was developed. Measurements of changes in absorbance at 610 nm were used as criterion of the oxidation progress. In order to maximize the sensitivity, different experimental reaction parameters were carefully studied via factorial screening and optimized by multivariate method. The linearity, intraday, and interday assay precision and accuracy were determined. The absorbance-concentration plot corresponding to tap water spiked samples was rectilinear, over the range of 7.56 × 10−6–3.22 × 10−5 mol L−1, with detection and quantitation limits of 2.49 × 10−6 mol L−1 and 7.56 × 10−6 mol L−1, respectively. The proposed method was successfully validated for the application of the determination of the drug in the spiked tap water samples and the percentage recoveries were 94.0–105.0%. The method is simple and does not require expensive instruments or complicated extraction steps of the reaction product. [ABSTRACT FROM AUTHOR]

A method was developed for the identification and quantification of oxytetracycline residues present in salmon muscle and skin using UV-Vis derivative spectrophotometry. With this method, it was possible to reduce the number of steps in the procedure typically required for instrumental analysis of a sample. The spectral variables, order of the derivative, scale factor, smoothing factor, and analytical wavelength were optimized using standard solutions of oxytetracycline dissolved in 900 mg/L oxalic acid in methanol. The matrix effect was significant; therefore, quantification for oxytetracycline residues was carried out using drug-free salmon muscle and skin samples fortified with oxytetracycline. The LOD and LOQ were found to be 271 and 903 μg/kg, respectively. The precision and accuracy of the method were validated using drug-free salmon muscle and skin tissues fortified at three different concentrations (8, 16, and 32 mg/kg) on 3 different days. The recoveries at all fortified concentrations were between 90 and 105%, and RSDs in all cases were less than 6.5%. This method can be used to screen out compliant samples and thereby reduce the number of suspect positive samples that will require further confirmatory analysis. [ABSTRACT FROM AUTHOR]

A new method for the determination and extraction of ethinyl estradiol and etonogestrel was developed for a pharmaceutical product consisting of a solid copolymer intrauterine ring for subsequent simultaneous quantification by ultraviolet-visible derivative spectrophotometry. The spectral variables were optimized for first derivative spectrophotometry with a smoothing factor of 4000 and an amplification factor of 10,000. A wavelength of 291.5 nm was selected for the determination of ethinyl estradiol by a graphical method, while for etonogestrel, zero-crossing was used at 249.5 nm. The limits of detection and quantification for ethinyl estradiol were 9.5 × 10−7and 9.0 × 10−6 mol/L and 1.1 × 10−6and 3.2 × 10−6 mol/L for etonogestrel, respectively. For the extraction method, the variables affecting the analytical signal were the extraction solvent, temperature, and extraction time; optimized conditions were 180 min at 76 ± 2°C in acetonitrile. The method was applied successfully for the first time to analyze intrauterine contraceptive rings. The sample contained 11.7 mg etonogestrel and 2.7 mg ethinyl estradiol; the recoveries were 93.6 ± 1.1% etonogestrel and 97.9 ± 1.5% ethinyl estradiol relative to the nominal concentration. The importance of this method involves its implementation in pharmaceutical laboratories. [ABSTRACT FROM PUBLISHER]

Abstract: In this work, a characterization of reagent chromophere 5-(4-sulphophenylazo)-8-aminoquinoline [SPA] by IR and 1H RMN was carried out and a pK a value of 3.55±0.03 was found as well. An 1:2 stoichiometry for the Cu(II)-SPA complex was determined at pH 9 by Job and molar ratio methods. A value of 1.4×1014 for the stability constant was also found. Based on the formation of this complex a new method for the copper determination in presence of gold and silver was developed by derivative spectrophotometry using a previous preconcentration on solid phase. In this method, the analytical measures were executed directly in the solid phase containing the complex. The Cu(II) reacts with the reagent chromophere SPA previously retained in the anionic exchange DEAE Sephadex A25. In this determination, the first derivative at 605nm was used. The quantification range was between (3.2±0.3×10−1)×10−8 and (94.4±0.9)×10−8 molL−1 (3.2±0.3×10−1)×10−8 , and (94.4±0.9)×10−8 molL−1. The repeatability expressed as RSD was between 1.1 and 2.0%. The method was applied successfully for the copper determination in mineral residuals and natural water samples. The results were consistent with those provided by ICP-mass spectrometry. [Copyright &y& Elsevier]

The article reports on the results of a study of copper and silver on SP Sephadex C25 as complexes with 1-phenyl-1,2-propanedione-2-oximethiosemicarbazone by derivative spectrophotometry. A description of the experimental set-up and measurement method is presented. The results of the study were consistent with those provided by inductively coupled plasma/mass spectrometry.

Abstract: A new method for the simultaneous determination of copper and gold was developed by derivative spectrophotometry using a previous preconcentration on solid phase. The method is based on the formation of Cu(II)-PPDOT and Au(III)-PPDOT complexes that are extracted from aqueous solution in only 20min on cationic exchange SP Sephadex C25. In this simultaneous determination, the second derivative and the zero crossing method were used. The copper and gold determinations were carried out at 278.0nm and 282.0nm, respectively. The determination range for both analytes was 1.6×10−8–141×10−8 molL−1. Good levels of repeatability (RSD) of 1.3% and 1.4% were observed for copper and gold, respectively. The method was applied successfully for the copper and gold determination in mineral residuals, minerals and natural water samples. The results were consistent with those provided by ICP-mass spectrometry. [Copyright &y& Elsevier]

Focuses on the development of a method for the sequential determination of attapulgite and nifuroxazide in pharmaceutical determinations by spectrophotometry. Studies of solvent, light and temperature effects; Requirement to obtain stable compounds for analytical purposes; Evaluation of the second-derivative spectra in the same samples.

This work presents a simple and fast method for the simultaneous determination of amiloride and furosemide by digital derivative spectrophotometry. HCl 1×10−2 mol/l dissolved in ethanol was used as solvent and to extract drugs from formulations. Subsequently the samples were evaluated directly by first digital derivative spectrophotometry, using a smoothing factor of 8 and scale factor of 1×10−4. The simultaneous determination of furosemide and amiloride can be carried out at 241.4 and 343.6 nm, respectively. In both cases, the zero crossing approach was used. When both compounds are present together in a sample, it is possible to quantify one in the presence of the other, without mutual interference. The determination range was found to be of 6.9×10−8 to 16×10−5 and 6.8×10−8 to 8×10−5 mol/l, for amiloride and furosemide, respectively. A good level of repeatability (RSD) of 0.9 and 0.6% was observed for amiloride and furosemide, respectively. The ingredients commonly found in commercial pharmaceutical formulations do not interfere. The proposed method was applied to the determination of these drugs in pharmaceutical formulations. [Copyright &y& Elsevier]

A new method for the simultaneous determination of iron and ruthenium at ultra-trace levels is proposed. The method is based on the formation of the iron and ruthenium complexes with 2,4,6-tri-(2-pyridil)-1,3,5-triazine (TPTZ) in the presence of hydroxylamine hydrochloride and buffer CH2ClCOOH/CH2ClCOONa (pH=3.0). The formation of the complexes and their retention on a cationic resin SP-Sephadex C25 were integrated in one step at 90 °C, with stirring for 90 min. Under these conditions a high preconcentration level was achieved for both analytes. The complexes retained on the solid phase were evaluated by second derivative spectrophotometry. The selected analytical wavelengths were 539.7 and 553.3 nm for the determination of ruthenium and iron, respectively, by using the zero crossing approach. The detection and quantification limits were 0.54 ng ml−1 and 1.79 ng ml−1 for ruthenium and 0.41 ng ml−1 and 1.38 ng ml−1 for iron. The proposed method was applied to the determination of both analytes in synthetic mixtures. [Copyright &y& Elsevier]

Introduction: This is the case of a 15-year-old boy who had been socially isolated in his house for over 1 year. He had become increasingly agitated, but refused any help offered. Objectives: To establish the role of community treatment in adolescents with mental health problems. Methods: Summary of the interventions taken place during the treatment Results: Initially this young person refused any medical treatment, so we tried first supportive therapy and CBT. He dicho not obtain any benefits as he appeared experiencias paranoid ideation and thoughts of being persecuted in the streets. With support from the occupational therapist, the young person started to take care of his personal hygiene. Afterwards he started to take oral medication with partial response. We decided to switch to im treatment. In conjunction with CBT, the young person was gradually able to llaves the house. All the sessions during the first fewmonths took place at his family home. These visits were weekly or twice weekly. Once he left the house, he attended the grupos at the day hospital. After 18months, he was dischargedwithout medication and he is currently studying for a degree. Conclusions: Community treatment in adolescent with mental health problems is a better opción to establish good rapport and avoid stressful situations that could take place in an in-patient facilita. [ABSTRACT FROM AUTHOR]

A simple method by first derivative spectrophotometry is proposed for the simultaneous determination of o-nitrophenol and p-nitrophenol. The analytes were separated from samples by liquid-liquid extraction (pH = 7.4) as tetrabutylammonium ion pairs into the 1,2-dichloroethane organic phase and subsequently the extracts were evaluated directlyby derivative spectrophotometry. Simultaneous determination of both analytes could be carried out using the zero-crossing and the graphical methods for o-nitrophenol and p-nitrophenol, respectively. The determination ranges were found to be between 0.115 to 3.00 ppm and 0.130 to 3.00 ppm for o-nitrophenol and p-nitrophenol, respectively. The relative standard deviations were in all instances less than 2.0%. The proposed method was applied to the determination of these compoundsin fruit juices. [ABSTRACT FROM AUTHOR]

Copper mining activities are very important in central Chile. Like other metals, copper is a nutrient for most plants at low concentration levels; however, at higher levels it may become toxic. At present, copper abundance in mediterranean ecosystems is unknown both for vegetation and soils. In this study, two localities of the Coastal Range in central Chile were studied. Copper content was found to be mainly related to site type, and secondly to the components of the ecosystem. Copper contents are similar to other mediterranean ecosystems of the world. Soil was found to represent the main source of data variation. [ABSTRACT FROM AUTHOR]

Abstract: The present study shows the formation and characterization of the ionic-pair between the antibiotic oxytetracycline and the dye crystal violet in ammonia solution pH 9.0±0.2 extracted into chloroform. The characterization was demonstrated using UV–vis spectrophotometry, 1H NMR, measurement of relaxation times T 1 and IR spectroscopy, using a comparison between the signals of individual pure compounds with the signals with the mixture CV–OTC in different alkaline media. The formation of ionic-pair was also corroborated by new signals and chemical shifts. (2D) NMR spectroscopy experiments show that the interaction is electrostatic. [Copyright &y& Elsevier]