Liftable homeomorphisms of rank two finite abelian branched covers

Archiv der Mathematik - We investigate branched regular finite abelian A-covers of the 2-sphere, where every homeomorphism of the base (preserving the branch locus) lifts to a homeomorphism of the...     

Enhancement of the Activity and Enantioselectivity of Lipase by Sol–Gel Encapsulation Immobilization onto β-cyclodextrin-Based Polymer

Candida rugosa lipase was encapsulated within a chemically inert sol–gel support prepared by polycondensation with tetraethoxysilane and octyltriethoxysilane in the presence of β-cyclodextrin-based polymer. The catalytic activity of the encapsulated lipases was evaluated both in the hydrolysis of p-nitrophenylpalmitate and the enantioselective hydrolysis of racemic Naproxen methyl ester. It has been observed that the percent activity yield of the encapsulated lipase was 65 U/g, which is 7.5 times higher than that of the covalently immobilized lipase. The β-cyclodextrin-based encapsulated lipases had higher conversion and enantioselectivity compared with covalently immobilized lipase. The study confirms an excellent enantioselectivity (E >300) for the encapsulated lipase with an enantiomeric excess value of 98% for S-naproxen.     

Inhibitory Effect of Sodium Alginate Nanoemulsion Coating Containing Myrtle Essential Oil (Myrtus communis L.) on Listeria monocytogenes in Kasar Cheese

The present study aimed to characterize the physical properties of nanoemulsion-based sodium alginate edible coatings containing myrtle (Myrtus communis L.) essential oil and to determine its inhibitory effects on Listeria monocytogenes in fresh Kasar cheese during the 24-day storage at 4 °C. The GC-MS analysis showed that the main components of myrtle essential oil were 1,8-cineol (38.64%), α-pinene (30.19%), d-limonene (7.51%), and α-ocimene (6.57%). Myrtle essential oil showed an inhibitory effect on all tested L. monocytogenes strains and this effect significantly increased after ultrasonication. Minimum inhibitory and minimum bactericidal concentrations of myrtle essential oil nanoemulsion were found to be 4.00–4.67 mg/mL and 5.00–7.33 mg/mL, respectively. The antibacterial activity of myrtle essential oil nanoemulsion against L. monocytogenes was confirmed by the membrane integrity and FESEM analyses. Nanoemulsion coatings containing myrtle essential oil showed antibacterial activity against L. monocytogenes with no adverse effects on the physicochemical properties of cheese samples. Nanoemulsion coatings containing 1.0% and 2.0% myrtle essential oil reduced the L. monocytogenes population in cheese during the storage by 0.42 and 0.88 log cfu/g, respectively. These results revealed that nanoemulsion-based alginate edible coatings containing myrtle essential oil have the potential to be used as a natural food preservative.     

A Simple and Low-Cost Electrochemical Immunosensor for Ultrasensitive Determination of Calreticulin Biomarker in Human Serum

An early on time detection of breast cancer significantly affects the treatment process and outcome. Herein, a new label-free impedimetric biosensor is developed to determine the lowest change in the level of calreticulin (CALR), which is a new biomarker of breast carcinoma. The proposed immunosensor is fabricated by using reduced graphene oxide/amino substituted polypyrrole polymer (rGO-PPyNH₂) nanocomposite modified disposable electrode. The anti-CALR antibodies are first attached on the rGO-PPyNH₂ nanocomposite coated electrode through glutaraldehyde crosslinking; the CALR antigens are then immobilized with the addition of CALR antigens to form an immunocomplex on the sensing surface. This immunocomplex induces considerably larger interfacial electron transport resistance (R_ct). The variation in the R_ct has a linear relationship with CALR level in the detection range of 0.025 to 75 pg mL⁻¹, with a detection limit of 10.4 fg mL⁻¹. The suggested biosensor shows high selectivity to CALR, good storage stability (at least 5 weeks) and suitable reproducibility results as shown in quality control chart. The designed immunosensor is utilized to analyze CALR levels in human sera with satisfying results. This immunosensor provides a novel way for the clinical determination of CALR and other cancer biological markers.     

Kinetic adsorption of drugs using carbon nanofibers in simulated gastric and intestinal fluids

Two different classes of drugs were selected to test the adsorption capacity of carbon nanofibers as a greener new generation alternative adsorbent in simulated gastric and intestinal fluids. Kinetics of the promethazine and trimethoprim adsorption were analyzed using Lagergren first order and Pseudo second order models. Intraparticle diffusion graphs were also plotted to discuss the adsorption mechanism. Kinetic data showed the significance of boundary layer effect for both of the drugs and the presence of intraparticle diffusion as the other rate controlling step for the promethazine adsorption. Giles isotherms showed the high affinity of drug molecules to the adsorbent. Maximum adsorption capacity of drugs was calculated using Langmuir model as 18.35 and 41.15 mg/g for trimethoprim and 95.24 and 80.65 mg/g for promethazine in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF), respectively. Trimethoprim adsorption was under favor of hydrophobic interaction and π-π dispersion interactions while promethazine adsorption was through cation exchange where the electrostatic attraction is an important force with the contribution of dispersion interactions.     

Interval transportation problem: feasibility,optimality and the worst optimal value

Central European Journal of Operations Research - We consider the model of a transportation problem with the objective of finding a minimum-cost transportation plan for shipping a given...