<abstract><title style='display:none'>Abstract</title>This article proposes four relationships of dynamic viscosity temperature dependence for a nonaddtivated mineral oil. The purpose of this study was to find a polynomial or exponential dependence between temperature and dynamic viscosity of mineral oil, using the Andrade equation changes. Equation constants A, B, C and D were determined by fitting polynomial or exponential.</abstract>

A new viscosity-temperature relationship for mineral oil SAE 10W

<abstract><title style='display:none'>Abstract</title>Huge amounts of used lubricating oils from automotive sources are disposed of as a harmful waste into the environment. For this reason, means to recover and reuse these wastes need to be found. Problems arising from acid treatment include environmental problems associated with the disposal of acid sludge and spent earth, low product yield (45-65%) and incomplete removal of metals. The processes of re-refining of used lubricating oils depend greatly on the nature of the oil base stock and on the nature and amount of contaminants in the lubricant resulting from operations. The study was carried out on a sample of 15W40 type used oil collected from one automobile. The re-refining process of used oil consists of dehydration, solvent extraction, solvent stripping and vacuum distillation. This study aims to investigate a process of solvent extraction of an alcohol-ketone mixture as a pre-treatment step followed by vacuum distillation at 5 mmHg. The primary step was conducted before the solvent extraction that involves dehydration to remove the water and fuel contaminants from the used oil by vacuum distillation. The solvent extraction and vacuum distillation steps were used to remove higher molecular weight contaminants. The investigated solvent to oil ratios were 2, 3, 4, 5 and 6. The solvent composition is 25% 2-propanol, 50% 1- butanol and 25% butanone or methyl ethyl ketone (MEK). The percentage of oil recovery for the solvent to oil ratio of 6:1 is further improved, but for the ratio values higher than 6:1, operation was considered economically not feasible. Finally, the re-refined oil properties were compared with the commercial virgin lubricating oil properties.</abstract>

Ovidius University of Constanta, Department of Chemistry and Chemical Engineering, 124 Mamaia Blvd, 900527 Constanta, Romania

“Auto Axel” Ltd., W. Maracineanu Str, No. 7, Postal code: 700373 – Iaşi, Romania

Regeneration of used engine lubricating oil by solvent extraction

<abstract><title style='display:none'>Abstract</title>The objective of the present work was to adapt the Prussian Blue reaction for the determination of ascorbic acid. The procedure was successfully applied for the determination of ascorbic acid in red and white grapes (<italic>Vitis vinifera </italic>L.) just previous ingathering. In the present work was used the red and white grapes from Murfatlar vineyard: Mamaia, Cabernet Sauvignon, Merlot, Pinot Noir, Chardonnay, Sauvignon, Muscat Ottonel and Riesling Italian. The results were situated in the range of 0.67 - 1.79 mg vitamin C/100g product for red grapes and respectively 0.50 - 1.49 mg vitamin C/100g for white grapes.</abstract>

Department of Chemistry and Chemical Engineering, University “Ovidius” of Constantza, 124 Mamaia Blvd, 900527, Constantza, Romania

Polytechnic University of Bucharest, Department of Analytical Chemistry and Environmental Engineering, 1-7 Polizu Street, 011061, Bucharest, Romania

Spectrophotometric determination of ascorbic acid in grapes with the Prussian Blue reaction

<abstract><title style='display:none'>Abstract</title> The aim of this research is to characterize some distilled drinks commercially available on the market (brandy, gin, vodka, whiskey) and some distilled beverages provided by private manufacturers (palinca made in copper, aluminum and stainless steel distillation apparatus). For this purpose the alcoholic concentration, the dry extract, the total acidity, the ash content and copper level were determined. The alcoholic concentration was measured using the picnometer method and the copper content was determined by UV-VIS molecular absorption spectrometric method. This study shows that the distilled beverages commercially available on the market can be discriminated from palinca, a homemade brandy using the differences between the obtained results.</abstract>

Quality control of distilled beverages

<abstract><title style='display:none'>Abstract</title>The refined rapeseed oil were carefully studied in recent years because they may constitute a raw material for biodegradable lubricants getting organic. These oils are an alternative to synthetic mineral oils. This article presents rheological behavior of refined rapeseed oil. The dynamic viscosity of refined rapeseed oil was determined at temperatures range between 313 - 363 K and shear rates range from 3.3 - 120 s-1. For temperature ranging between 313 - 363 K refined rapeseed oil has a Bingham fluid behavior.</abstract>

A study of rheological behavior for refined rapeseed oil

<abstract><title style='display:none'>Abstract</title>The petroleum refining industry has a significant influence on the total pollution of the environment by industrial discharges and wastes. In the operation of petroleum refineries, the atmosphere is polluted with hydrogen sulfide, sulfur dioxide, nitrogen oxides, carbon monoxide, hydrocarbons, and other toxic substances. The main pollutants are sulfur dioxide and hydrocarbons. The fresh water used by refineries in product cooling is returned to the original source of water containing crude oil, petroleum products, and mineral salts as contaminants. The extent of air and water pollution depends on the particular processing technology, control measures that are employed and also on the scale of the processing. In working out these measures, the primary attention of scientific-research institutes and design and planning organizations must be directed not only towards how to reduce the contaminating and poisoning action of industrial discharges on the environment, but primarily towards preventing or minimizing these discharges in the refineries.</abstract>

Environmental pollution in the petroleum refining industry

<abstract>
<title style='display:none'>Abstract</title>
The objective of this study was to synthesize some novel substituted 4-(2-methoxynaphthalen-6-yl) pyrimidine- 2(1<italic>H</italic>)-thione compounds using sodium hydroxide catalyzed three component condensation and cyclization reaction of substituted 6-methoxy-2-acetonapthone, various substituted benzaldehydes and thiourea. These thione derivatives were characterized by their analytical, physical, and spectroscopic data. In addition, the <italic>in vitro</italic> antibacterial activities of these pyrimidine derivatives were evaluated using Bauer-Kirby disc diffusion method.
</abstract>

Synthesis, spectral study and evaluation of antibacterial activity of some novel 4-(6-methoxynaphthalen-2-yl)-6-(substituted aryl)pyrimidine-2(1<italic>H</italic>)-thiones

<abstract>
<title style='display:none'>Abstract</title>
In this work, the influence of process parameters (temperature: 25 - 65 °C, ethanol content in the extraction solvent: 30 - 90 vol.%, and solid-to-solvent ratio: 1:15 - 1:45 w/v) on the process of ultrasound-assisted extraction (UAE) of (poly)phenols from blueberry leaves (<italic>Vaccinium myrtillus</italic>) was investigated. Statistical analysis was performed using the MINITAB 21 software, with the application of three-level full factorial designs. The Responses in the study are the content of total (poly)phenols, flavonoids and anthocyanins in the obtained extracts. The extraction of blueberry leaf was significantly (p &lt; 0.05) impacted by process variables. The R2, Adjusted R2, and Predicted R2 values in the study are high, showing a significant relationship between the independent variables and the Response. The optimal temperature for all three Responses is 65 °C, the optimal solid-to-solvent ratio for total (poly)phenols and anthocyanins is 1:45 w/v and for flavonoids is 28.03 w/v, while the optimal ethanol content in the solvent for total (poly)phenols, flavonoids and anthocyanins is 51.21 vol.%, 50.61 vol.% and 83.33 vol.%, respectively.
</abstract>

Optimization of ultrasound-assisted extraction (UAE) of (poly)phenolic compounds from blueberry (<italic>Vaccinium myrtillus</italic>) leaves using full-factorial design

<abstract>
<title style='display:none'>Abstract</title>
In this study, the extent of Pb contamination around an active military shooting range is re-assessed to ascertain current contamination status comparatively to data’s reported 20 years ago. This is because lead bullet disintegration and mobility takes several years and extensively affects levels of soil-Pb contamination. A total of 120 topsoil samples were collected within the impact area (front) and non-impact area (back) for Pb determination. High concentrations of Pb were found at impact berm both front (28940±2996 μg/g) and back (775±128 μg/g). Spatial distribution of contamination reflects the distances from berm. Soil-Pb contamination around non-impact area was notable at back berm through to 100 m distance with significant difference in Pb, Cr, Ni and Zn levels. Concentration of Pb at berm was observed to have increase five-fold over a period of about twenty years from previous study with accumulation factor of about 1000. Principal component analysis PCA indicated 67 % of total metal load of range soil was majorly from impact areas of the berm. The correspondence analysis relay plot shows pollution order of Pb &gt; Ni &gt; Cd &gt; Cr &gt; Zn &gt; Cu. This confirms soil contamination especially around the impact area, i.e. impact berm and firing lines and non-impact area at 0 m, 10 m, 50 m and 100 m. Environmental consequence of high soil-Pb levels within the range especially non-impact areas utilized for farming activities will leave much to desire. Hence, extensive and continuous monitoring is needed. However, remediation through appropriate soil washing technique could reduce Pb levels and improve soil condition regardless of age.
</abstract>

Assessment of spatial distribution of lead in soils around an active military shooting range

<abstract>
<title style='display:none'>Abstract</title>
The health risk of polychlorinated biphenyls (PCBs) exposure from Ugbuwangue, Ugbori and Edjeba rivers sediments in Warri-South, Warri, Delta State was investigated. Nine sediment samples were collected; three samples each along the course of the different rivers. The sediment samples were Soxhlet extracted with acetone/dichloromethane/<italic>n</italic>hexane (1:1:1 v/v). A total of 28 PCBs were quantified using gas chromatography coupled with mass spectrometry detector. The concentration of the 28 PCBs ranges from 178.76-1398.29 ng g−1 for Ugbuwangue river, 224.81-685.19 ng g-1 for Ugbori river and 539.33-7858.3 ng g−1 for Edjeba river. The concentration of 12 PCBs were recorded for dioxin-like PCBs ranged from 0.08-401.52 ng g−1 (Ugbuwangue river 0.13 to 223.11 ng g−1, Ugbori river 0.08 to 153.39 ng g−1 and Edjeba river 0.32 to 401.52 ng g−1), while the concentration of 16 non-dioxin-like PCBs were recorded ranging from 0.13-4245.71 ng g−1 (Ugbuwangue river 0.18 to 386.47 ng g−1, Ugbori river 0.13 to 111.98 ng g−1 and Edjeba river 0.31 to 4245.71 ng g−1). The ecological risks of the nine sediment samples were investigated and it ranges from 25.52 – 1122.616 with Edjeba river sediment having the highest ecological risk while Ugbuwangue river sediment has the least ecological risk.
</abstract>

Health risk assessment of polychlorinated biphenyls exposure from inland rivers sediments in Warri-South, Warri, Delta State

<abstract>
<title style='display:none'>Abstract</title>
In this study, 3,4-ethylenedioxypyrrole (EDOP) and pyrrole (Py) copolymers were prepared by chemical and electrochemical polymerization methods. The properties of the polymers obtained by both methods were compared. Chemical synthesis of copolymers was carried out with ferric chloride (FeCl3) in the acetonitrile (ACN) environment. The electrochemical synthesis was carried out with lithium perchlorate (LiClO4) electrolyte and suitable oxidation potential range in ACN solution. The properties of polypyrrole (PPy) copolymers were performed with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and conductivity measurements. Depending on the polymerization method and pyrrole amount in copolymer, thermal stability, conductivity and surface morphology were varied.
</abstract>

Preparation and characterization of chemically and electrochemically synthesized 3,4-ethylenedioxy pyrrole/pyrrole (EDOP/Py) copolymers

<abstract>
<title style='display:none'>Abstract</title>
This study evaluated the properties and potential applications of <italic>Cyperus rotundus</italic> tubers resin, a herbaceous plant native to North Africa, Asia, and Australia. The resin was evaluated for yield, phenolic composition, antioxidant activity, anti-inflammatory potential, and sun protection factor (SPF). Results showed that the resin contained five types of phenolic compounds, namely vanillic acid, gallic acid, caffeic acid, quercetin, and rutin. The resin exhibited significant antioxidant activity in all assays tested, with IC50 values ranging from 0.0638 to 0.454 mg/mL. The SPF value of the resin was determined to be 5.794, suggesting its potential as a sunscreen. The resin also showed significant anti-inflammatory activity in both human serum albumin (HSA) and egg albumin denaturation assays. Overall, the findings of this study suggest that <italic>Cyperus rotundus</italic> tubers resin is a promising source of natural antioxidants and anti-inflammatory compounds. It has the potential to be used in a variety of applications, including food and beverage products, cosmetics, and pharmaceuticals. This study is an important step in understanding the properties and applications of <italic>Cyperus rotundus</italic> tubers resin. The results indicate that this natural product has great potential in a variety of health applications.
</abstract>

<italic>Cyperus rotundus</italic> tubers resin from Algeria: a promising source of natural antioxidants, anti-inflammatory, and photoprotective compounds

<abstract><title style='display:none'>Abstract</title>In view of ensuring healthy agricultural foods for human consumption, this study assessed the human health risk implicated in selected heavy metals in some commonly consumed vegetables, tubers, nuts and fruits grown around the quarry sites at Ishiagu, Ebonyi State, Nigeria. Samples from agriculture area of Umudike, Abia State, Nigeria, constituted the control. The concentration of Mn, Zn, Fe, Cu, Cd, and Pb, were determined using atomic absorption spectrometry. The potential non-carcinogenic health risk for consumers which included Estimated Daily Intake (EDI) and Target Hazard Quotients (THQ) for Pb, Fe, Mn, Zn, Cd and Cu while carcinogenic health risk using Cancer Slope Factors (CSF) was established for Cd and Pb. Relative abundance of heavy metals across the locations and all samples was in the order Fe &gt; Mn &gt; Zn &gt; Pb &gt; Cu &gt; Cd. There was statistical significant effect of quarrying activities on the concentration of the heavy metals (Fe, Mn, Zn, Pb, Cu, Cd) at p &lt; 0.05 level. Based on the observed bioconcentration factors, cassava showed more hyperaccumulation potential compared to other samples. Pumpkin and bitter leaf also could be used in remediation owing to their high bioaccumulation index for Pb and Zn. THQ obtained for Mn and Pb were &gt;1 indicating that the residents at the quarry site may be exposed to potential non-carcinogenic health risk due to Mn and Pb intoxication. With respect to US EPA prescriptions, average carcinogenic risk values obtained for Pb and Cd in this study indicated a lifetime (70 years) probability of contracting cancer suggesting that they be placed for further consideration as chemicals of concern with respect to the assessed locals. </abstract>

Human health risk assessment of heavy metals in soils and commonly consumed food crops from quarry sites located at Isiagwu, Ebonyi State

<abstract><title style='display:none'>Abstract</title> Lipase-catalyzed biodiesel production is being the object of extensive research due to the demerits of chemical based catalytic system. Lipase immobilized on Fe3O4 magnetic nanoparticles has the integrated advantages of traditional immobilized lipase and free lipase for its rather fast reaction rate and easy separation. It has been demonstrated that free lipase NS81006 has potential in catalyzing the alcoholysis of renewable oils for biodiesel preparation. In this study, Fe3O4 magnetic nanoparticles functionalized with organosilane compounds like (3-aminopropyl)triethyloxysilane (APTES) and (3-mercaptopropyl)trimethoxysilane) MPTMS were used as carriers for lipase immobilization. Lipase NS81006 was covalently bound to the organosilane-functionalized magnetic nanoparticles by using glutaraldehyde cross-linking reagent. A biodiesel yield of 89% and 81% could be achieved by lipase immobilized on APTES-Fe3O4 and MPTMS-Fe3O4 magnetic nanoparticles respectively under optimized conditions of oil to methanol molar ratio 1:3 with three step addition of methanol, reaction temperature 45°C and reaction time duration 12 h. The lipases immobilized on magnetic nanoparticles could be recovered easily by external magnetic field for further use.</abstract>

Lipase NS81006 immobilized on Fe3O4 magnetic nanoparticles for biodiesel production

<abstract>
<title style='display:none'>Abstract</title>
Nucleosides and their analogues are an important, well-established class of clinically useful medicinal agents that exhibit antiviral and anticancer activity. Thus, our research group has focused on the synthesis of new nucleoside derivatives that could be tested for their broad-spectrum biological activity. In this study, two new series of nucleoside derivatives were synthesized from uridine (<bold>1</bold>) through facile two-step reactions using the direct acylation method, affording 5’-<italic>O</italic>-acyl uridine derivatives in good yields. The isolated uridine analogs were further transformed into two series of 2’,3’-di-<italic>O</italic>-acyl derivatives bearing a wide variety of functionalities in a single molecular framework to evaluate their antimicrobial activity. The new synthesized compounds were characterized through physicochemical, elemental and spectroscopic analysis, and all were screened for their <italic>in vitro</italic> antimicrobial activity against selected human and plant pathogenic strains. The test compounds revealed moderate to good antibacterial and antifungal activities and were more effective against fungal phytopathogens than against bacterial strains, while many of them exhibited better antimicrobial activity than standard antibiotics. Minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) tests against all microorganisms were also conducted for five compounds based on their activity (<bold>6</bold>, <bold>11</bold>, <bold>13</bold>, <bold>16</bold>, and <bold>17</bold>). In addition, all the derivatives were optimized using density functional theory (DFT) B3LYP/6-31g+(d,p) calculations to elucidate their thermal and molecular orbital properties. A molecular docking study was performed using the human protein 5WS1 to predict their binding affinity and modes, and ADMET and SwissADME calculations confirmed the improved pharmacokinetic properties of the compounds. Besides, structure–activity relationship (SAR), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) studies were also performed. Thus, the improvement of the bioactivity of these compounds is expected to significantly contribute to the design of more antimicrobial agents for therapeutic use in the future.
</abstract>

Synthesis, characterization, synergistic antimicrobial properties and molecular docking of sugar modified uridine derivatives

<abstract><title style='display:none'>Abstract</title> Thermodynamic properties of lead species in aqueous solution are collected. The chemical equilibria between various forms of Pb(II) are considered. The speciation diagrams for the equilibria 4[PbOH]+(aq) ⇄ [Pb4(OH)4]4+(aq) and 2[Pb3(OH)4]2+(aq) ⇄ [Pb6(OH)8]4+(aq), and the thermodynamic activity - pH diagram of Pb(II) species are plotted. Basic chemical and electrochemical equilibria for lead are calculated. The potential - pH diagram for Pb - H2O system is revised.</abstract>

The revised potential – pH diagram for Pb – H2O system

<abstract><title style='display:none'>Abstract</title> Statistical analysis starts with the assessment of the distribution of experimental data. Different statistics are used to test the null hypothesis (H0) stated as Data follow a certain/specified distribution. In this paper, a new test based on Shannon’s entropy (called Shannon’s entropy statistic, H1) is introduced as goodness-of-fit test. The performance of the Shannon’s entropy statistic was tested on simulated and/or experimental data with uniform and respectively four continuous distributions (as error function, generalized extreme value, lognormal, and normal). The experimental data used in the assessment were properties or activities of active chemical compounds. Five known goodness-of-fit tests namely Anderson-Darling, Kolmogorov-Smirnov, Cramér-von Mises, Kuiper V, and Watson U2 were used to accompany and assess the performances of H1. </abstract>

Performances of Shannon’s Entropy Statistic in Assessment of Distribution of Data

<abstract><title style='display:none'>Abstract</title> In recent years black mussels are one of the most commercially important species from the Bulgarian Black Sea. The marine mollusks are valuable healthy food, low in calories and fats and high in proteins. They are a major dietary source of fat soluble pigments - astaxanthin, carotenoids and polyunsaturated fatty acids (PUFA). To our knowledge the information about the nutritional quality of mussels from the Bulgarian Black Sea waters, based on chemical composition, fat soluble pigments, cholesterol and PUFA content is very limited. The aim of the present study is to determine and compare protein, lipid, carbohydrate and energy values, fat soluble pigments, cholesterol and fatty acid composition in farmed mussels (Mytilus galloprovincialis) from the Bulgarian northern and southern parts of the Black Sea coast. The mussel samples were analyzed for lipids (Bligh &amp; Dyer method), crude proteins (Kjeldahl method), carbohydrates and moistures according to the AOAC (1990) methods. Fatty acids were analyzed by the GC-MS system. Fat soluble pigments and cholesterol were analyzed simultaneously by the RP-HPLC system. Lipid and protein content were found to be higher in mussels from the northern region. In accordance with the Commission Regulation (EC) No. 116/2010 all analyzed mussel samples can be classified as high in protein and low in fats and carbohydrates. The amount of cholesterol, contained in all mussel populations is significantly low, while the omega-3 (n-3) is significantly higher than the omega-6 PUFA. A portion of 100 g edible tissue provides 0.500 g more of the required amount of eicosapentaenoic acid (20:5) and docosahexaenoic acid (22:6) n-3 PUFA according to EFSA (2012). It can be concluded that the studied mussel aquaculture in the Black Sea is beneficial food for the human health and it is advisable to be part of a proper or a preventive diet of Bulgarian consumers.</abstract>

Nutritional evaluation of aquaculture mussels (M. galloprovincialis) from the Black Sea, Bulgaria

Publication Ethics and Publication Malpractice Statement

Instructions for Authors

Open Access License