Prediction of Ionic Cr (VI) Extraction Efficiency in Flat Sheet Supported Liquid Membrane Using Artificial Neural Networks (ANNs)

ABSTRACT:Artificial neural networks (ANNs) are computer techniques that attempt to simulate the functionality and decision-making processes of the human brain. In the past few decades, artificial neural networks (ANNs) have been extensively used in a wide range of engineering applications. There are only a few applications in liquid membrane process. The objective of this research was to develop artificial neural networks (ANNs) model to estimate Cr (VI) extraction efficiency in feed phase.Data set (413 experiment records) were obtained from a laboratory scale experimental study. Various combinations of experimental data, namely % (w/w) extractant Alamine 336 concentration in membrane phase, stirring speed in feed and stripping phase, flat sheet support type, stripping phase NaOH concentration, feed phase pH, diluents type, % (w/w) diluents concentration, polymer support type, extractant type, and time are used as inputs into the ANN so as to evaluate the degree of effect of each of these variables on Cr (VI) extraction efficiency in feed phase. The results of the ANN model is compared with multiple linear regression model (MLR). Mean square error (MSE), average absolute relative error (AARE) and coefficient of determination (R 2 ) statistics are used as comparison criteria for the evaluation of the model performances. Based on the comparisons, it was found that the ANN model could be employed successfully in estimating the Cr (VI) extraction efficiency

In vivo glioblastoma growth is reduced by apyrase activity in a rat glioma model

BACKGROUND: ATP is an important signalling molecule in the peripheral and central nervous system. Both glioma growth and tumor resection induces cell death, thus liberating nucleotides to the extracellular medium. Nucleotides are hydrolyzed very slowly by gliomas when compared with astrocytes and induce neuronal cell death and glioma proliferation. The objective of the present study was to test the involvement of extracellular ATP in glioblastoma growth in a rat glioma model. METHODS: To deplete the extracellular ATP, the enzyme apyrase was tested on the treatment of gliomas implanted in the rats CNS. One million glioma C6 cells in 3 microliters of DMEM/FCS were injected in the right striata of male Wistar rats, 250–270 g. After 20 days, the rats were decapitated and the brain sectioning and stained with hematoxylin and eosine. We performed immunohistochemical experiments with Ki67, CD31 and VEGF. Total RNA was isolated from cultured glioma C6 cells and the cDNA was analyzed by Real Time-PCR with primers for the NTPDase family. RESULTS: C6 glioma cells effectively have a low expression of all NTPDases investigated, in comparison with normal astrocytes. The implanted glioma co-injected with apyrase had a significant reduction in the tumor size (p < 0.05) when compared with the rats injected only with gliomas or with gliomas plus inactivated apyrase. According to the pathological analysis, the malignant gliomas induced by C6 injection and co-injected with apyrase presented a significant reduction in the mitotic index and other histological characteristics that indicate a less invasive/proliferative tumor. Reduction of proliferation induced by apyrase co-injection was confirmed by counting the percentage of Ki67 positive glioma cell nuclei. According to counts with CD31, vessel density and neoformation was higher in the C6 group 20 days after implantation. Confirming this observation, rats treated with apyrase presented less VEGF staining in comparison to the control group. CONCLUSION: These results indicate that the participation of extracellular ATP and the ecto-nucleotidases may be associated with the development of this type of brain tumor in an in vivo glioma model

Clinical and organizational factors associated with mortality during the peak of first COVID-19 wave: the global UNITE-COVID study

Purpose: To accommodate the unprecedented number of critically ill patients with pneumonia caused by coronavirus disease 2019 (COVID-19) expansion of the capacity of intensive care unit (ICU) to clinical areas not previously used for critical care was necessary. We describe the global burden of COVID-19 admissions and the clinical and organizational characteristics associated with outcomes in critically ill COVID-19 patients. Methods: Multicenter, international, point prevalence study, including adult patients with SARS-CoV-2 infection confirmed by polymerase chain reaction (PCR) and a diagnosis of COVID-19 admitted to ICU between February 15th and May 15th, 2020. Results: 4994 patients from 280 ICUs in 46 countries were included. Included ICUs increased their total capacity from 4931 to 7630 beds, deploying personnel from other areas. Overall, 1986 (39.8%) patients were admitted to surge capacity beds. Invasive ventilation at admission was present in 2325 (46.5%) patients and was required during ICU stay in 85.8% of patients. 60-day mortality was 33.9% (IQR across units: 20%–50%) and ICU mortality 32.7%. Older age, invasive mechanical ventilation, and acute kidney injury (AKI) were associated with increased mortality. These associations were also confirmed specifically in mechanically ventilated patients. Admission to surge capacity beds was not associated with mortality, even after controlling for other factors. Conclusions: ICUs responded to the increase in COVID-19 patients by increasing bed availability and staff, admitting up to 40% of patients in surge capacity beds. Although mortality in this population was high, admission to a surge capacity bed was not associated with increased mortality. Older age, invasive mechanical ventilation, and AKI were identified as the strongest predictors of mortality

Co-infection and ICU-acquired infection in COIVD-19 ICU patients: a secondary analysis of the UNITE-COVID data set

Background: The COVID-19 pandemic presented major challenges for critical care facilities worldwide. Infections which develop alongside or subsequent to viral pneumonitis are a challenge under sporadic and pandemic conditions; however, data have suggested that patterns of these differ between COVID-19 and other viral pneumonitides. This secondary analysis aimed to explore patterns of co-infection and intensive care unit-acquired infections (ICU-AI) and the relationship to use of corticosteroids in a large, international cohort of critically ill COVID-19 patients.Methods: This is a multicenter, international, observational study, including adult patients with PCR-confirmed COVID-19 diagnosis admitted to ICUs at the peak of wave one of COVID-19 (February 15th to May 15th, 2020). Data collected included investigator-assessed co-infection at ICU admission, infection acquired in ICU, infection with multi-drug resistant organisms (MDRO) and antibiotic use. Frequencies were compared by Pearson's Chi-squared and continuous variables by Mann-Whitney U test. Propensity score matching for variables associated with ICU-acquired infection was undertaken using R library MatchIT using the "full" matching method.Results: Data were available from 4994 patients. Bacterial co-infection at admission was detected in 716 patients (14%), whilst 85% of patients received antibiotics at that stage. ICU-AI developed in 2715 (54%). The most common ICU-AI was bacterial pneumonia (44% of infections), whilst 9% of patients developed fungal pneumonia; 25% of infections involved MDRO. Patients developing infections in ICU had greater antimicrobial exposure than those without such infections. Incident density (ICU-AI per 1000 ICU days) was in considerable excess of reports from pre-pandemic surveillance. Corticosteroid use was heterogenous between ICUs. In univariate analysis, 58% of patients receiving corticosteroids and 43% of those not receiving steroids developed ICU-AI. Adjusting for potential confounders in the propensity-matched cohort, 71% of patients receiving corticosteroids developed ICU-AI vs 52% of those not receiving corticosteroids. Duration of corticosteroid therapy was also associated with development of ICU-AI and infection with an MDRO.Conclusions: In patients with severe COVID-19 in the first wave, co-infection at admission to ICU was relatively rare but antibiotic use was in substantial excess to that indication. ICU-AI were common and were significantly associated with use of corticosteroids

Selective separation of cobalt and nickel by supported liquid membranes

The selective separation of cobalt from acidic media, containing both equimolar and nonequimolar mixtures of cobalt and nickel. was examined by supported liquid membranes using Alamine 336 as mobile carrier dissolved in various diluents. The membrane support was microporous hydrophobic polypropylene Celgard 2500 (25 mu m thick, 0.209 x 0.054 mu m pore size and 55% porosity). Acetic acid-Na acetate buffer was used for the adjustment of the feed pH which was critical. Various parameters were experimentally studied and the optimum conditions were determined. (C) 2009 Elsevier B.V. All rights reserved

OA; TBP; synergistic extraction; facilitated mass transfer

In present study, the synergistic separation of Cr(VI) has been investigated from synthetic acidic solution containing Cr(VI), Co(II) and Ni(II) by flat sheet supported liquid membrane (FSSLM) technique using triisooctylamine (TIOA) and tri-n-butyl phosphate (TBP) as carriers. The main goal of the study was based in the exploring of the synergistic effect of TBP on selective extraction of Cr(VI) in presence of Co(II) and Ni(II) ions. The various parameters related with membrane and aqueous solution properties were studied to identify the optimum extraction and stripping conditions of the Cr(VI) through FSSLM. In the optimum conditions, initial mass flux (J(0)) and separation factors (beta(Cr/Co) and beta(Cr/Ni)) were obtained as 1.49 x 10(-05) (kg/m(2.)s), 382.2 and 725.3 respectively from aqueous H2SO4 media through Celgard 2500 (Celgard Inc., USA) polymer support. As a result, the considerable synergistic influence on selective transport of Cr(VI) through FSSLM using TIOA and TBP as carriers has been identified

membrane using Alamine 300 as carrier

Cobalt and nickel are among the most important nonferrous metals. The using of flat sheet supported liquid membranes (FSSLMs) to remove metals from wastewaters has been used actively by the scientific and industrial communities. In this study, the selective separation of cobalt from thiocyanate solutions containing cobalt and nickel by FSSLM was examined using tri-n-octylamine (Alamine 300) as carrier. The FSSLM was consisted of extractant, flat sheet support and organic solvent. The various parameters were studied to determine the optimum extraction and striping conditions of cobalt and nickel. These parameters were stirring speeds of phases, NH4SCN concentration, pH, diluent type, extractant concentration, stripping reagent concentration and modifier concentration. Concentration of cobalt and nickel were determined by Shimadzu AA-6701GF spectrophotometer. In the optimum conditions, selective separation of cobalt was achieved with an efficiency of 98.4% within 8 h, for equimolar feed mixtures, 400 mg/L Co + 400 mg/L Ni, and the separation factor of Co(II) over Ni(II) was 234.4. In addition, for nonequimolar feed mixtures, 500 mg/L Co + 1000 mg/L Ni, Ni in excess, selective separation of cobalt was 99.9%, and the separation factor of Co was 506 in the same time. (C) 2011 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved

Ionic-Liquid-Based Solvent-Extraction Technique

In this study, the selective extraction and stripping conditions of Co(II) from acidic thiocyanate solution containing Co(II) and Ni(II) by ionic-liquid-based solvent-extraction technique using symmetric and asymmetric imidazolium bromide salts substituting butyl and isobutyl groups were experimentally optimized. The molecular structure effect of imidazolium bromide salts (IMs) have been determined as main factor to extract Co(II). The executive parameters on stripping and extraction processes, such as IMs concentration, pH, thiocyanate concentration, stripping reagent type, and concentration, were experimentally investigated. Molecular variation of organometalic complex (adduct) consisting of IMs and Co-SCN, were illuminated by comparision of ATR-FTIR spectrums of pure and Co-SCN loaded IMs. Stoichiometric rates of the adduct was verified with slope analysis. In light of these examinations, Co(SCN)(3)(-) has been determined as prominent Co-SCN species in aqueous media. Symetric IMs were identified as more effective than asymmetric ones on selective separation of Co(II) from Ni(II). Under optimum conditions, 99.20% of Co(II) was extracted and 93.33% of Co(II) was recovered with higher separation factors especially in diluted solution, whereas, Ni(II) extractions were negligible. We have concluded that the separation power of this study is high in Co(II)/Ni(II) containing dilute solutions and it can be used in preconcentration purposes effectively

DETERMINATION BY ICP/MS OF TRACE METAL CONTENT IN TEN EDIBLE WILD

The determination of nineteen trace metal levels (Li, Be, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Sn, Sb, Te, Hg and Pb) was performed for ten naturally growing edible mushroom species in three different provinces of Turkey. The possibility of using the mushrooms as a bio-indicator of enviromnental pollution was investigated. Trace metal contents were determined by inductively coupled plasma mass spectrometry (ICP-MS), after wet digestion procedure. The highest amounts of Li, Al, V, Fe and Se were found in C. cornucopioides (0.41, 285.92, 0.595, 300.87 and 0.780 mu g g(-1), respectively), the highest amounts of Co, Ni, Cu, Sb and Hg were found in H. lacunosa (1.736, 1.687, 13.22, 0.452 and 0.402 mu g g(-1), respectively), the highest amounts of Cr and Zn were found in S. squamosus (0.700 and 29.16 mu g g(-1), respectively), the highest amounts of Te and Pb were found in T anatolicum (0.007 and 1.102 mu g g(-1), respectively), the highest amounts of Be were found in M costata (0.018 mu g g(-1)), and the highest levels of Mn were found in R. roseolus (8.49 mu g g(-1)). The Pb, Cd, Cr, As, Ni, Sn and Hg contents determined in the edible mushrooms which we analysed were lower than the observed values in literature. Also, available data indicate that the mushroom collection area was not polluted by toxic heavy metals. These data are important in the fields of toxicology, food chemistry and environmental protection

Determination by ICP/MS of trace metal content in ten edible wild mushrooms from Turkey

The determination of nineteen trace metal levels (Li, Be, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Sn, Sb, Te, Hg and Pb) was performed for ten naturally growing edible mushroom species in three different provinces of Turkey. The possibility of using the mushrooms as a bio-indicator of environmental pollution was investigated. Trace metal contents were determined by inductively coupled plasma mass spectrometry (ICP-MS), after wet digestion procedure. The highest amounts of Li, Al, V, Fe and Se were found in C. cornucopioides (0.41, 285.92, 0.595, 300.87 and 0.780 µg g–1, respectively), the highest amounts of Co, Ni, Cu, Sb and Hg were found in H. lacunosa (1.736, 1.687, 13.22, 0.452 and 0.402 µg g–1, respectively), the highest amounts of Cr and Zn were found in S. squamosus (0.700 and 29.16 µg g–1, respectively), the highest amounts of Te and Pb were found in T. anatolicum (0.007 and 1.102 µg g–1, respectively), the highest amounts of Be were found in M. costata (0.018 µg g–1), and the highest levels of Mn were found in R. roseolus (8.49 µg g–1). The Pb, Cd, Cr, As, Ni, Sn and Hg contents determined in the edible mushrooms which we analysed were lower than the observed values in literature. Also, available data indicate that the mushroom collection area was not polluted by toxic heavy metals. These data are important in the fields of toxicology, food chemistry and environmental protection. © 2015, Scibulcom Ltd. All rights reserved