Covalent immobilization of active lysozyme on Si/glass surface using alkoxy Fischer carbene complex on SAM

A cross-metathesis reaction between an alkene terminated self-assembled monolayer (SAM) on glass/Si wafer and an alkene tethered Fischer carbene complex yielded a functionalized surface. Rapid aminolysis of the Fischer carbene moieties permit efficient anchoring of amine containing molecules on such a surface. Attachment of 1-pyrenemethylamine was thus monitored by ATR-IR spectroscopy and fluorescence microscopy. Similarly, BSA and lysozyme were individually grafted to such Fischer carbene modified surfaces using their pendant lysine residues. It has been demonstrated that the anchored lysozyme retains its bactericidal property.     

Fingerprint chemotaxonomic GC–TOFMS profile of wood and bark of mangrove tree Sonneratia caseolaris (L.) Engl.

The bark and wood of Sonneratia caseolaris (L.) Engl. have been analyzed for chemical profile by GC–TOFMS. Overall thirty-two compounds from bark and twenty-eight compounds from wood have been detected. Sixteen constituents have been found to be common in both the extracts. GC–TOFMS chemical profile may be a significant finger print chemotaxonomic marker as an identity of this plant.     

Calix[4]azacrowns as ionophores for liquid?Cliquid extraction and facilitated transport of biological supramolecular complexes

The native and methyl ester amino acids have been extracted by calix[4]azacrowns 1 (1,3-[ethylene-bis-aminocarbonylmethoxy)]-p-tert-butylcalix[4]arene) and 2 (1,3-[propylene-bis-aminocarbonylmethoxy)]-p-tert-butyl-calix[4]arene) from an aqueous phase into a chloroform phase and transported through a chloroform liquid membrane as ion pairs in the presence of picrate or tropaeolin 00 as counter ions aiming their separation. The amino acids under study exhibited good extractability by calix[4]azacrowns 1 and 2. Both receptors 1 and 2 showed good extractability towards amino acids under study. The results are discussed in term of correlation of structural properties of amino acids and calix[4]azacrowns involved in experiments. In this respect, the influence of chain length of receptors upon extraction and transport of amino acids, and the nature of anions used as counter ions are evaluated.     

Synthesis of Some C2‐Symmetric Bidentate Ligands and Their Complexes Derived from Feist's Acid

Various new C₂‐symmetric bidentate ligands, bearing phosphorus, nitrogen, and sulfur, were obtained in an efficient manner, starting from (±)‐trans‐3‐methylidenecyclopropane‐1,2‐dicarboxylic acid (Feist's acid; (±)‐trans‐ 3 ). The structures of the new bidentate ligands, di(tert‐butyl) (±)‐[(trans‐3‐methylidenecyclopropane‐1,2‐diyl)dimethanediyl]biscarbamate ((±)‐ 9 ), (±)‐(trans‐3‐methyldienecyclopropane‐1,2‐diyl)dimethanaminium dichloride ((±)‐ 10 ), (±)‐S,S′‐[(trans‐3‐methylidenecyclopropane‐1,2‐diyl)dimethanediyl] diethanethioate ((±)‐ 11 ), and (±)‐[(trans‐3‐methylidenecyclopropane‐1,2‐diyl)dimethanediyl]bis(diphenylphosphane) ((±)‐ 12 ), were fully characterized by standard spectroscopic techniques. These new classes of C₂‐symmetric bidentate ligands have the potential to be used in asymmetric catalysis.     

Effect of rotation on plane waves in generalized thermo-microstretch elastic solid with a relaxation time

The present paper is aimed at studying the effect of rotation on the general model of the equations of generalized thermo-microstretch for a homogeneous isotropic elastic half-space solid whose surface is subjected to a Mode-I Crack problem considered. The problem is in the context of the generalized thermoelasticity Lord-?hulman??s (L-S) theory with one relaxation time, as well as the classical dynamical coupled theory (CD) The normal mode analysis is used to obtain the exact expressions for the displacement components, force stresses, temperature, couple stresses and microstress distribution. The variations of the considered variables through the horizontal distance are illustrated graphically. Comparisons are made with the results in the presence and absence of rotation and in the presence and absence of microstretch constants between the two theories.     

Chemical Profile,Antioxidant Properties and Antimicrobial Activities of Malaysian Heterotrigona itama Bee Bread

The aim of the study was to determine the chemical profile, antioxidant properties and antimicrobial activities of Heterotrigona itama bee bread from Malaysia. The pH, presence of phytochemicals, antioxidant properties, total phenolic content (TPC) and total flavonoid content (TFC), as well as antimicrobial activities, were assessed. Results revealed a decrease in the pH of bee bread water extract (BBW) relative to bee bread ethanolic extract (BBE) and bee bread hot water extract (BBH). Further, alkaloids, flavonoids, phenols, tannins, saponins, terpenoids, resins, glycosides and xanthoproteins were detected in BBW, BBH and BBE. Also, significant decreases in TPC, TFC, DPPH activity and FRAP were detected in BBW relative to BBH and BBE. We detected phenolic acids such as gallic acid, caffeic acid, trans-ferulic acid, trans 3-hydroxycinnamic acid and 2-hydroxycinnamic acid, and flavonoids such as quercetin, kaempferol, apigenin and mangiferin in BBE using high-performance liquid chromatography analysis. The strongest antimicrobial activity was observed in Klebsilla pneumonia (MIC₅₀ 1.914 µg/mL), followed by E. coli (MIC₅₀ 1.923 µg/mL), Shigella (MIC₅₀ 1.813 µg/mL) and Salmonella typhi (MIC₅₀ 1.617 µg/mL). Bee bread samples possess antioxidant and antimicrobial properties. Bee bread contains phenolic acids and flavonoids, and could be beneficial in the management and treatment of metabolic diseases.     

The effects of hazardous ions adsorption on the morphological and chemical properties of reactive cloth filter

Reactive cloth filter is fabricated by grafting of acrylonitrile/methacrylic acid onto cotton cloth, using mutual irradiation technique and the subsequent amidoximation of the reactive intermediate nitrile groups. The incorporation of the amidoxime/carboxyl groups was confirmed by different techniques. The effect of the hazardous ions chelation from radioactive waste on the morphological and chemical structure was studied. The cloth filter possessed good morphological and chemical stability suitable for practical use. The fabricated cloth filter can be used for low-level radioactive waste treatments.     

Spectrofluorimetric method for measuring the activity of the enzyme α-l-fucosidase using the ion associate of 2-chloro-4-nitro phenol-rhodamine-B

A low cost and accurate method for the detection and analytical determination of the activity of the enzyme α-l-fucosidase (AFU) was developed. The method was based upon measuring the fluorescence intensity of the complex ion associate of the ion associate of rhodamine-B and the compound 2-chloro-4-nitrophenol (RB⁺ CNP⁻) at 580 nm in phosphate buffer (pH 5) against the reagent blank. The influence of the different parameters, e.g. pH, incubation time, temperature, 2-chloro-4-nitrophenol concentration, foreign ions and surfactants that control the fluorescence intensity of the produced ion associate was critically investigated. The correlation between the fluorescence activity of the enzyme AFU by the developed procedures and the standard method was positive and highly significant in patients and controls (r² = 0.99, p < 0.001). The developed method is simple and proceeds without practical artifacts compared to the standard method.     

Synthesis and antibacterial evaluation of new N- and S-glycosides analogues with dinitrophenyl-substituted heterocyclic bases

Four N- and S-glycosides 13–16 having nucleobases 7–12 binding to sugar molecules from one side and to 3,5-dinitrophenyl moieties from another side were synthesized from 3,5-dinitrobenzoic acid 2. The synthetic intermediates, hydrazide 5 and thiosemicarbazide 6 regarded as important key compounds for the synthesis of nucleobases 7–12, each was obtained by two approaches. Structures of synthesized compounds were determined spectroscopically. Antibacterial activities for synthetic intermediates and glycosides were assessed using the paper disk diffusion method against Gram-negative bacteria: Pseudomonas aeruginosa, Pseudomonas fluorescens, and Escherichia coli and Gram-positive bacteria: Bacillus cereus and Staphylococcus aureus. Some of the synthetic compounds showed variant activity against some of the microorganisms tested. Nucleobases 8–10 and 12 showed moderate to slight activity against microorganisms under test at relatively high concentration, while the N-glycosides 14 and 15 exhibited persistent effect even at lower concentrations. Commercially available antibiotics polymyxine and oxytetracycline were used as positive controls.     

Synthesis and electrochemical characterization of nitrogen-doped and nitrogen–phosphorus-doped multi-walled carbon nanotubes

Nitrogen-doped and nitrogen–phosphorus-doped multi-walled carbon nanotubes (N-MWCNTs and N–P-MWCNTs, respectively) were fabricated by chemical vapor deposition and characterized using scanning electron microscopy and transmission electron microscopy in combination with energy dispersive X-ray spectroscopy and Raman spectroscopy. The electrochemical response of N-MWCNTs and N–P-MWCNTs towards ferrocyanide/ferricyanide was initially studied. The findings exhibit weakening of electrochemical response and sensitivity of nanotubes with phosphorus doping, and thus, within the composite films tested, those consist exclusively of N-MWCNTs exhibit the greatest electrocatalytic activity. N–P-MWCNT film was further applied for individual electrochemical analysis of ascorbic acid (AA), uric acid (UA), and dopamine (DA), and lower limits of detections of 11.6, 7.8, and 1.9 μM were estimated, respectively. The findings demonstrate that AA does not interfere with UA, but considerable interference of AA in analysis of DA was observed. Thus, the simultaneous analysis of AA, UA, and DA on N–P-MWCNTs appears to be restricted.