140 research outputs found

    Removal of Solophenyl Red 3BL Dye from Textile Effluents by Adsorption Using a Natural Adsorbent Oxalis pes-caprae L.

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    The aim of the present study was to assess the adsorption potential of a natural adsorbent Oxalis pes-caprae L. for the removal of azo-dye solophenyl red 3BL (SR 3BL) from textile effluents. The adsorbent was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The effect of various parameters on the efficiency of the adsorption was studied. The optimum was found with the contact time of 35 minutes, pH of 6, and temperature of 25 °C. The equilibrium experimental data were fitted with the Langmuir, Freundlich, and Temkin models. Experimental data were well described with the Langmuir isotherm indicating monolayer adsorption. Pseudo-first-order, pseudo-second-order, and Elovich kinetic models were used to evaluate the adsorption kinetics. The adsorption kinetics was found to follow closely the pseudo-first-order kinetic model. Thermodynamics studies revealed that the adsorption process was spontaneous and exothermic. This work is licensed under a Creative Commons Attribution 4.0 International License

    Effect of supervised exercise on physical function and balance in patients with intermittent claudication

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    Background The aim of the study was to identify whether a standard supervised exercise programme (SEP) for patients with intermittent claudication improved specific measures of functional performance including balance. Methods A prospective observational study was performed at a single tertiary vascular centre. Patients with symptomatic intermittent claudication (Rutherford grades 1–3) were recruited to the study. Participants were assessed at baseline (before SEP) and 3, 6 and 12 months afterwards for markers of lower-limb ischaemia (treadmill walking distance and ankle : brachial pressure index), physical function (6-min walk, Timed Up and Go test, and Short Physical Performance Battery (SPPB) score), balance impairment using computerized dynamic posturography with the Sensory Organization Test (SOT), and quality of life (VascuQoL and Short Form 36). Results Fifty-one participants underwent SEP, which significantly improved initial treadmill walking distance (P = 0·001). Enrolment in a SEP also resulted in improvements in physical function as determined by 6-min maximum walking distance (P = 0·006), SPPB score (P < 0·001), and some domains of both generic (bodily pain, P = 0·025) and disease-specific (social domain, P = 0·039) quality of life. Significant improvements were also noted in balance, as determined by the SOT (P < 0·001). Conclusion Supervised exercise improves both physical function and balance impairment

    Electrochemical M2+ recognition by an amidopyridyl-tetrathiafulvalene derivative

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    A tetrathiafulvalene-based redox-responsive receptor incorporating amide and pyridyl coordinating units exhibits an original multi-wave electrochemical recognition behaviour towards Cd(II)

    Developing Guidelines for Assessing the Effectiveness of Intelligent Compaction Technology

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    Many factors affect pavement compaction quality, which can vary. Such variability may result in an additional number of passes required, extended working hours, higher energy consumption, and negative environmental impacts. The use of Intelligent Compaction (IC) technology during construction can improve the quality and longevity of pavement structures while reducing risk for contractors and project owners alike. This study develops guidelines for the implementation of IC in the compaction of pavement layers as well as performing a preliminary life-cycle cost analysis (LCCA) of IC technology compared to the conventional compaction approach. The environmental impacts of the improved construction process were quantified based on limited data available from the case studies. The LCCA performed in this study consisted of different scenarios in which the number of operating hours was evaluated to estimate the cost efficiency of the intelligent compaction technique during construction. The analyses showed a reduction in energy consumption and the production of greenhouse gas (GHG) emissions with the use of intelligent compaction. The LCCA showed that the use of IC technology may reduce the construction and maintenance costs in addition to enhancing the quality control and quality assurance (QC/QA) process. However, a more comprehensive analysis is required to fully quantify the benefits and establish more accurate performance indicators. A draft version of the preliminary guidelines for implementation of IC technology and long-term monitoring of the performance of pavement layers compacted thereby is also included in this report

    Carboxylic acid derivatives of tetrathiafulvalene: key intermediates for the synthesis of redox-active calixarene-based anion receptors

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    A series of calixarene–TTF (TTF=tetrathiafulvalene) receptors incorporating amide binding units for anion recognition have been synthesized and characterized. For this purpose, two synthetically versatile new TTF carboxylic acid derivatives were prepared and characterized by X-ray diffraction, these structures demonstrating the critical role of the carboxylic function in the solid-state organization. Some of the calixarene–amide–TTF assemblies exhibit strong binding of various anions, as shown by 1H NMR titration studies, and one receptor is able to electrochemically respond in the presence of H2PO4−, C6H5CO2− or CH3CO2− anion

    Chemical composition analysis of essential oils of four plants from Aurès region of Algeria and their antibacterial and antibiofilm activities against coagulase-negative staphylococci

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    Background: The altitudinal and geographical variability of the Aurès mountains of Algeria favored the existence of some endemic and rare varieties of medicinal plants. The aim of the present work is to determine the chemical composition, antimicrobial and antibiofilm properties of the  essential oils (EOs) from aerial parts of four medicinal plants from Aurès region of Algeria; Juniperus thurifera L., Juniperus oxycedrus L., Salvia   officinalis L. and Thymus ciliatus ssp. munbyanus (Boiss. & Reut.) Batt. on coagulase negative staphylococci (CoNS) isolates. Methodology: Extraction of EOs from the four plant materials was carried out by hydro-distillation, and the EO yield expressed in gram of the distillate per 100 grams of dry matter. The chemical composition of the EOs was analyzed by gas chromatography-mass spectrometry (GC-MS) method. In vitro antibacterial and antibiofilm activities of the EOs were evaluated against CoNS previously isolated at the Anti-Cancer Center of Batna, Algeria using the agar disc diffusion assay and biofilm inhibition study, respectively. Minimum inhibitory concentration (MIC) and minimum  bacterial concentration (MBC) of the EOs of S. officinalis L. and T. ciliatus ssp. munbyanus were determined by the dilution method. Results: Twenty-seven and 41 compounds rich in monoterpene hydrocarbons were identified from J. oxycedrus and J. thurifera plants respectively, while 45 and 32 compounds, constituted mainly by oxygenated monoterpenes, were identified from S. officinalis L. and T. ciliatus ssp. munbyanus, respectively. The EOs of T. ciliatus ssp. munbyanus showed the most inhibitory activity of all the four plants on CoNS isolates (n=66) with mean  inhibition zone diameter of 24.99±6.29mm, and mean MIC and MBC values of 2.65±3.77mg/ml and 5.31±7.41mg/ml respectively, followed by S.  officinalis L., with mean inhibition zone diameter of 13.38± 6.52mm, and mean MIC and MBC values of 27.53±28.2 mg/ml and 31.97±33.19 mg/ml  respectively (p<0.0001 by one-way ANOVA). Also, percentage biofilm inhibition of CoNS isolates (n=59) was high for EOs of T. ciliatus ssp. munbyanus  (65.63±10.71%) and S. officinalis L. (53.13±5.83%), although was significantly higher for T. ciliatus ssp. munbyanus compared to S. officinalis L. (p<0.0001, t=7.874). Conclusion: Essential oils from T. ciliatus ssp. munbyanus and S. officinalis L. could represent an alternative to classical antibiotics against planktonic cells and biofilms of CoNS

    Virus en sistemas acuáticos e implicaciones en salud pública

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    The use of the hydraulic resources by humans raised the interest on the presence of virus in aquatic systems, due to the public health risk they represent. We present a revision on the occurrence of virus in different aquatic systems, the diseases caused produced by human virus and their symptoms, including enterovirus, rotavirus, astrovirus, calicivirus, adenovirus and hepatitis A virus. Implications in public health in relation with the existing regulations for human use and consumption, as well as residual treated and reused water, are analyzed. We mention the impact of viral diseases related the water for human use and consumption, giving some idea of Mexico´s situation. The methods used for the detection of virus, as well as the common methods for water disinfection used for human with a specific focus on viral contamination. We conclude that human viruses capable to persist in the environment have severe effects, specially for infants. The results of this revision suggest that research should be conducted in Mexico and other tropical areas to know what is the situation with viral contamination in groundwater, freshwater and treated wastewater for reuse. It is relevant the evaluation of enterovirus as indicators of the presence of viral fecal contamination and bacteriophages intenting to include them in the water quality standards.El aprovechamiento de los recursos hídricos por el hombre, ha despertado interés sobre la presencia de virus en sistemas acuáticos debido al riesgo que representan para la salud pública. Se realiza una revisión sobre la presencia de virus en diferentes sistemas acuáticos, las enfermedades causadas por virus humanos y sus síntomas, incluyendo enterovirus, rotavirus, astrovirus, calicivirus, adenovirus y virus de hepatitis A. Se analizan también las implicaciones para la salud en relación con la normatividad vigente para agua de uso y consumo humano, así como para agua residual tratada y reutilizada. Se trata el impacto de las enfermedades virales relacionadas con uso y consumo de agua en la población, mencionando la situación en México. Se describen los métodos que se emplean para la detección de virus, así como los métodos más comunes de desinfección para agua de uso y consumo humano, con un enfoque específico sobre contaminación viral. Se concluye que los virus entéricos capaces de persistir en el ambiente tienen el potencial de causar efectos severos en la salud, especialmente de la población infantil. Los resultados de esta revisión sugieren que en México y otras zonas tropicales se deben realizar investigaciones para conocer cual es la situación en cuanto a contaminación viral del agua subterránea, superficial y agua residual tratada para reúso. Es relevante evaluar como agentes indicadores de contaminación viral fecal a los enterovirus y bacteriófagos con la intención de incluirlos en los estándares de calidad del agua

    Randomized clinical trial of percutaneous transluminalangioplasty, supervised exercise and combined treatment forintermittent claudication due to femoropopliteal arterial disease

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    Background:The aim was to compare percutaneous transluminal angioplasty (PTA), a supervisedexercise programme (SEP) and combined treatment (PTA plus SEP) for intermittent claudication dueto femoropopliteal arterial disease.Methods: Consenting patients with femoropopliteal arterial lesions were randomized to one of threetreatment arms: PTA, SEP, or PTA plus SEP. All patients received optimal medical treatment. Patientswere assessed at baseline and 1, 3, 6 and 12 months after intervention. Clinical (ankle pressures, walkingdistances, symptoms) and quality-of-life (QoL) outcomes (Short Form 36, VascuQol) were analysed.Results: A total of 178 patients (108 men, median age 70 years) were included. All three treatmentgroups demonstrated significant clinical and QoL improvements. One year after PTA (60 patients, 8withdrew), 37 patients (71 per cent) had improved (16 mild, 16 moderate, 5 marked), nine (17 per cent)showed no improvement and six (12 per cent) had deteriorated. After SEP (60 patients, 14 withdrew),32 patients (70 per cent) had improved (19 mild, 10 moderate, 3 marked), six (13 per cent) showed noimprovement and eight (17 per cent) had deteriorated. After PTA plus SEP (58 patients, 11 withdrew),40 patients (85 per cent) had improved (18 mild, 20 moderate, 2 marked), seven (15 per cent) showedno improvement and none had deteriorated. On intergroup analysis, PTA and SEP alone were equallyeffective in improving clinical outcomes, although the effect was short-lived. PTA plus SEP produced amore sustained clinical improvement, but there was no significant QoL advantage.Conclusion: For patients with intermittent claudication due to femoropopliteal disease, PTA, SEP,and PTA plus SEP were all equally effective in improving walking distance and QoL after 12 months.Registration number: NCT00798850 (http://www.clinicaltrials.gov)

    Systematic Study of Electron Localization in an Amorphous Semiconductor

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    We investigate the electronic structure of gap and band tail states in amorphous silicon. Starting with two 216-atom models of amorphous silicon with defect concentration close to the experiments, we systematically study the dependence of electron localization on basis set, density functional and spin polarization using the first principles density functional code Siesta. We briefly compare three different schemes for characterizing localization: information entropy, inverse participation ratio and spatial variance. Our results show that to accurately describe defect structures within self consistent density functional theory, a rich basis set is necessary. Our study revealed that the localization of the wave function associated with the defect states decreases with larger basis sets and there is some enhancement of localization from GGA relative to LDA. Spin localization results obtained via LSDA calculations, are in reasonable agreement with experiment and with previous LSDA calculations on a-Si:H models.Comment: 16 pages, 11 Postscript figures, To appear in Phys. Rev.

    A Quantitative Approach to the Watershed Governance Prism: The Duero River Basin, Mexico

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    Advances have been made in water resource investigation due to the implementation of mathematical models, the development of theoretical frameworks, and the evaluation of sustainability indices. Together, they improve and make integrated water resource management more efficient. In this paper, in the study area of the Duero River Basin, located in Michoacan, Mexico, we schematize a series of numerical indices of the Watershed Governance Prism to determine the quantitative status of water governance in a watershed. The results, presented as axes, perspectives, and prisms in the Axis Index, Water Governance Index, and Watershed Governance Prism Index, provide the conclusion that it is possible to establish and evaluate the Watershed Governance Prism Index using our numerical implementation of the Watershed Governance Prism theoretical framework. Thus, it is possible to define a quantitative status and evoke how water governance is being designed and implemented in a watershed
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