Concentration of apricot juice using complex membrane technology

In this study, pressed apricot (Prunus armeniaca L.) juice was concentrated using complex membrane technology with different module combinations: UF-RO-OD, UF-RO-MD, UF-NF-OD and UF-NF-MD. In case of the best combination a cross-flow polyethylene ultrafiltration membrane (UF) was applied for clarification, after which preconcentration was done using reverse osmosis (RO) with a polyamide membrane, and the final concentration was completed by osmotic distillation (OD) using a polypropylene module. The UF-RO-OD procedure resulted in a final concentrate with a 65-70 °Brix dry solid content and an excellent quality juice with high polyphenol content and high antioxidant capacity.Nanofiltration (NF) and membrane distillation (MD) were not proper economic solutions.The influence of certain operation parameters was examined experimentally. Temperatures of UF and RO were: 25, 30, and 35 °C, and of OD 25 °C. Recycle flow rates were: UF: 1, 1.5, and 2 m3 h−1; RO: 200, 400, and 600 l h−1; OD: 20, 30 and 40 l h−1. The flow rates in the module were expressed by the Reynolds number, as well. Based on preliminary experiments, the transmembrane pressures of UF and RO filtration were 4 bar and 50 bar, respectively. Each experimental run was performed three times. The following optimal operation parameters provided the lowest total cost: UF: 35 °C, 2 m3 h−1, 4 bar; RO: 35 °C, 600 l h−1, 50 bar; OD: 20, 30 and 40 l h−1; temperature 25 °C.In addition, experiments were performed for apricot juice concentration by evaporation, which technique is widely applied in the industry using vacuum and low temperature.For description the UF filtration, a dynamic model and regression by SPSS 14.0 statistics software were applied

Lipidna peroksidacija i aktivnost antioksidativnih enzima u eritrocitima radnika profesionalno izloženih aluminiju

Current research indicates that lipid peroxidation could have a role in aluminium toxicity. The aim of this study was to asses lipid peroxidation and antioxidative enzyme activity in erythrocytes of workers occupationally exposed to aluminium. We investigated a group of 59 workers (Al group) exposed to aluminium fumes (contamination factor F=8.07 to 13.47, national maximal allowed concentration value is 2 mg m-3). The control group (C group) consisted of 75 subjects employed in lime production who had not been occupationally exposed to aluminium or any known toxic substance. Erythrocyte aluminium concentrations were significantly higher in the exposed group than controls [Al group (8.41±3.66) µg L-1, C group (5.60±0.86) µg L-1, p<0.001]. In the Al group, erythrocyte malondialdehyde concentration was also significantly higher [Al group (189.59±81.27) µmol L-1, C group (105.21±49.62) µmol L-1, p<0.001] and antioxidative enzyme activity reduced for glucoso-6-phosphatedehydrogenase [Al group (5.05±1.70) IU g-1 Hb, C group (12.53±4.12) IU g-1 Hb, p<0.001], glutathione reductase [Al group (1.41±0.56) IU g-1 Hb, C group (1.89±0.57) IU g-1 Hb, p<0.001], glutathione peroxidase [Al group (12.37±5.76) IU g-1 Hb, C group (15.54±4.85) IU g-1 Hb, p<0.001], catalase [Al group (116.76±26.60) IU g-1 Hb, C group (158.81±71.85) IU g-1 Hb, p<0.001] and superoxide dismutase [Al group (1175.8±149.9) IU mg-1 Hb, C group (1377.9±207.5) IU mg-1 Hb, p<0.001].Rezultati suvremenih istraživanja pokazuju da lipidna peroksidacija može imati važnu ulogu u toksičnosti aluminija. Cilj istraživanja bio je da se ispita lipidna peroksidacija i aktivnost antioksidativnih enzima u eritrocitima kod radnika profesionalno izloženih aluminiju. Ispitivanjem je obuhvaćena skupina od 59 radnika (Al skupina) profesionalno izloženih aluminiju (faktor onečišćenja F=8,07 do 13,47, nacionalna maksimalno dopuštena koncentracija je 2 mg m-3). Kontrolna skupina sastojala se od 75 osoba zaposlenih u proizvodnji vapna koje nikada nisu bile profesionalno izložene aluminiju ni drugim toksičnim tvarima. U skupini izloženoj aluminiju utvrđene su statistički signifikantno više koncentracije aluminija u eritrocitima nego u kontrolnoj skupini [Al skupina (8,41±3,66) µg L-1, kontrolna skupina (5,60±0,86) µg L-1, p<0,001]. U Al skupini utvrđene su statistički značajno više koncentracije malondialdehida u eritrocitima [Al skupina (189,59±81,27) µmol L-1, kontrolna skupina (105,21±49,62) µmol L-1, p<0,001]. Također, u Al skupini utvrđene su i statistički značajno niže aktivnosti antioksidativnih enzima u eritrocitima: glukozo- 6-fosfatdehidrogenaza [Al skupina (5,05±1,70) IU g-1 Hb, kontrolna skupina (12,53±4,12) IU g-1 Hb, p<0,001], glutationreduktaza [Al skupina (1,41±0,56) IU g-1 Hb, kontrolna skupina (1,89±0,57) IU g-1 Hb, p<0,001], glutationperoksidaza [Al skupina (12,37±5,76) IU g-1 Hb, kontrolna skupina (15,54±4,85) IU g-1 Hb, p<0,001], katalaza [Al skupina (116,76±26,60) IU g-1 Hb, kontrolna skupina (158,81±71,85) IU g-1 Hb, p<0,001] i superoksiddizmutaza [Al skupina (1175,8±149,9) IU mg-1 Hb, kontrolna skupina (1377,9±207,5) IU mg-1 Hb, p<0,001]

Identifying risk factors for blood culture negative infective endocarditis: An international ID-IRI study

Background: Blood culture-negative endocarditis (BCNE) is a diagnostic challenge, therefore our objective was to pinpoint high-risk cohorts for BCNE. Methods: The study included adult patients with definite endocarditis. Data were collected via the Infectious Diseases International Research Initiative (ID-IRI). The study analysing one of the largest case series ever reported was conducted across 41 centers in 13 countries. We analysed the database to determine the predictors of BCNE using univariate and logistic regression analyses. Results: Blood cultures were negative in 101 (11.65 %) of 867 patients. We disclosed that as patients age, the likelihood of a negative blood culture significantly decreases (OR 0.975, 95 % CI 0.963–0.987, p &lt; 0.001). Additionally, factors such as rheumatic heart disease (OR 2.036, 95 % CI 0.970–4.276, p = 0.049), aortic stenosis (OR 3.066, 95 % CI 1.564–6.010, p = 0.001), mitral regurgitation (OR 1.693, 95 % CI 1.012–2.833, p = 0.045), and prosthetic valves (OR 2.539, 95 % CI 1.599–4.031, p &lt; 0.001) are associated with higher likelihoods of negative blood cultures. Our model can predict whether a patient falls into the culture-negative or culture-positive groups with a threshold of 0.104 (AUC±SE = 0.707 ± 0.027). The final model demonstrates a sensitivity of 70.3 % and a specificity of 57.0 %. Conclusion: Caution should be exercised when diagnosing endocarditis in patients with concurrent cardiac disorders, particularly in younger cases

Trace elements in hemodialysis patients: a systematic review and meta-analysis

<p>Abstract</p> <p>Background</p> <p>Hemodialysis patients are at risk for deficiency of essential trace elements and excess of toxic trace elements, both of which can affect health. We conducted a systematic review to summarize existing literature on trace element status in hemodialysis patients.</p> <p>Methods</p> <p>All studies which reported relevant data for chronic hemodialysis patients and a healthy control population were eligible, regardless of language or publication status. We included studies which measured at least one of the following elements in whole blood, serum, or plasma: antimony, arsenic, boron, cadmium, chromium, cobalt, copper, fluorine, iodine, lead, manganese, mercury, molybdenum, nickel, selenium, tellurium, thallium, vanadium, and zinc. We calculated differences between hemodialysis patients and controls using the differences in mean trace element level, divided by the pooled standard deviation.</p> <p>Results</p> <p>We identified 128 eligible studies. Available data suggested that levels of cadmium, chromium, copper, lead, and vanadium were higher and that levels of selenium, zinc and manganese were lower in hemodialysis patients, compared with controls. Pooled standard mean differences exceeded 0.8 standard deviation units (a large difference) higher than controls for cadmium, chromium, vanadium, and lower than controls for selenium, zinc, and manganese. No studies reported data on antimony, iodine, tellurium, and thallium concentrations.</p> <p>Conclusion</p> <p>Average blood levels of biologically important trace elements were substantially different in hemodialysis patients, compared with healthy controls. Since both deficiency and excess of trace elements are potentially harmful yet amenable to therapy, the hypothesis that trace element status influences the risk of adverse clinical outcomes is worthy of investigation.</p

Production of activated carbon materials from kenaf biomass to be used as catalyst support in aqueous-phase reforming process

In the present study, low value-added woody biomass, kenaf (Hibiscus cannabinus L.), was utilized for production of activated carbons (ACs) that can be used as catalyst support for deposition of metal particles such as Pt to produce highly active catalysts for gasification of biomass hydrolysates by aqueous-phase reforming (APR) process. H3PO4 was used as activating agent for production of AC materials. ACs produced from kenaf and non-hydrolyzed fraction of kenaf after dissolution in subcritical water were compared with the commercial one. The activated carbon material from kenaf had highest BET surface area and total pore volume among the materials tested including commercial AC. The catalyst prepared by Pt deposition on this material (kenaf AC-Pt) had also highest BET surface area and total pore volume. This catalyst exhibited very high activity and selectivity for hydrogen production (0.015 mol H2/g catalyst) in APR of biomass hydrolysate. © 2016 Elsevier B.V. All rights reserved

Efficient Separation of Oil-Water and Fatty Alcohol-Water Emulsions by Vacuum Filtration Using Bacterial Cellulose Membranes

The emulsions of water-insoluble organic compounds such as oil and fatty alcohol based solvents, are widely encountered in chemical industries and this type of emulsions have led to significant environmental pollution. Therefore, it is crucial to explore effective approaches for removal of waste oil and other fatty solvents present in aqueous emulsions. In this study two types of aqueous emulsions were studied to separate water; water/oil and 1-decanol/water emulsions. A vacuum membrane filtration system was used to separate the emulsions. Bacterial cellulose (BC) membranes were synthesized using Gluconacetobacter xylinus bacteria. Our findings demonstrate that BC membranes can effectively separate water from oil and fatty alcohol based solvent containing emulsions, thereby providing a viable solution for environmental remediation

Evaluation of various carbon materials supported Pt catalyts for aqueous-phase reforming of lignocellulosic biomass hydrolysate

Currently, under huge pressure from energy demands and environmental problems, much attention is being paid to produce fuel and chemicals from lignocellulosic biomass. In this matter, development of active and also recyclable catalysts are essential. In the present study, various types of carbon supported Pt reforming catalysts were prepared for use in gasification of wheat straw biomass hydrolysate by aqueous-phase reforming. The supports tested were various carbon materials having different surface and structures that were activated carbon (AC), single- and multi-walled carbon nanotubes (SWCNT and MWCNT), superdarco carbon (SDC) and graphene oxide (GO). The catalysts prepared using these supports were evaluated based on gasification yield, carbon amount consumed in the process, sugar alcohols formation and breaking down of organic compounds in the hydrolysate. Compared to other carbon-based supports tested, Pt on activated carbon showed best performance for gasification of biomass hydrolysate. This catalyst was also active on carbon consumption, sugar alcohols production and breaking down soluble organic compounds in the hydrolysate. The second active catalyst, Pt on single-walled carbon nanotube, showed significantly higher activity compared to multi-walled carbon nanotube since large polysaccharides molecules were not able to enter into narrow graphene sheets in multi-walled carbon nanotube to react with Pt deposited inside graphene layers. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved