Secretory Phospholipase A2 in Dromedary Tears: a Host Defense Against Staphylococci and Other Gram-Positive Bacteria

The best known physiologic function of secreted phospholipase A₂ (sPLA₂) group IIA (sPLA₂-IIA) is defense against bacterial infection through hydrolytic degradation of bacterial membrane phospholipids. In fact, sPLA₂-IIA effectively kills Gram-positive bacteria and to a lesser extent Gram-negative bacteria and is considered a major component of the eye’s innate immune defense system. The antibacterial properties of sPLA₂ have been demonstrated in rabbit and human tears. In this report, we have analyzed the bactericidal activity of dromedary tears and the subsequently purified sPLA₂ on several Gram-positive bacteria. Our results showed that the sPLA₂ displays a potent bactericidal activity against all the tested bacteria particularly against the Staphylococcus strains when tested in the ionic environment of tears. There is a synergic action of the sPLA₂ with lysozyme when added to the bacteria culture prior to sPLA₂. Interestingly, lysozyme purified from dromedary tears showed a significant bactericidal activity against Listeria monocytogene and Staphylococcus epidermidis, whereas the one purified from human tears displayed no activity against these two strains. We have also demonstrated that Ca²⁺ is crucial for the activity of dromedary tear sPLA₂ and to a less extent Mg²⁺ ions. Given the presence of sPLA₂ in tears and intestinal secretions, this enzyme may play a substantial role in innate mucosal and systemic bactericidal defenses against Gram-positive bacteria.     

Displacement gain dependent fidelity in quantum teleportation using entangled two-mode squeezed light

We study a scheme for quantum teleportation of a single-mode squeezed coherent state using entangled two-mode squeezed vacuum. We establish the analytic expression of displacement gain dependent fidelity in terms of the squeezing coherent parameter \(r\) and quantum channel parameter \(p\) . The dependence of the optimum displacement gain for teleporting a squeezed coherent state upon the EPR entanglement is discussed. It shows that the fidelity of teleportation can be improved by tuning the displacement gain. We find that the fidelity increases with the increase of EPR parameter, while it decreases with the increase of the squeezing coherent parameter of the signal. We get infinite squeezing as a resource is required for an ideal and perfect teleportation of unknown input states. We show that the nonclassical properties of an unknown state to be teleported can be preserved in the teleportation.     

1,2-Naphthoquinone-4-Sulphonic Acid Sodium Salt (NQS) as an Analytical Reagent for the Determination of Pharmaceutical Amine by Spectrophotometry

Abstract: Several papers have been presented in recent years regarding the field of application of 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS) as a chromogenic reagent for the determination of pharmaceutical amines using spectrophotometry. In this review article, various spectrophotometric methods using NQS as a labeling reagent for determination of pharmaceutical amines are presented. The application of these methods for the determination of drugs in pharmaceutical formulations and real samples is discussed.     

The effects of different possible modes of uniaxial strain on the tunability of electronic and band structures in $$\text {MoS}_2$$ monolayer nanosheet via first-principles density functional theory

Although it is important for the study of graphene, identifying and characterizing the number of graphene layers is challenging. In this paper, we calculate graphene’s transmission. The result shows that the phase change is more sensitive than the intensity change when light passes through graphene in some THz frequencies. Based on this fact, a simple route is presented for identifying the single or few layers of graphene sheets by using terahertz phase contrast microscopy (TPCM). The route is fast, and easy to be carried out.     

ADM-Padé solutions for generalized Burgers and Burgers-Huxley systems with two coupled equations

We present an approximate numerical solution to generalized Burgers and Burgers-Huxley systems with two coupled equations using the ADM-Padé technique which is a combination of the Adomian decomposition method and Padé approximation. The Padé technique is used to enhance the accuracy and speed up the convergence rate of the truncated series solution produced by the ADM. Results are given in graphical form for explicit examples of the two systems.     

Etude par RMN des 2-2′ -Dihalogeno-diethylethers—II: Effet de Solvant

Solvent effects on compounds of formula (X? CH₂? CH₂)₂O with X ? Cl, Br, I have been studied. The rotamer ratios have been determined for each solvent according to Lin's method and it is shown that the three compounds moved to gauche forms when increasing the medium dielectric constant. Additionally, it is shown that geminal couplings of the iodine derivative algebraically decrease on increasing the medium polarity. An attempt to correlate these variations with rotamer populations is made.     

Sémantique de type Kripke d'un système logique basé sur un ensemble ordonné fini

In order to modelize the reasoning of intelligent agents represented by a poset T, H. Rasiowa introduced logic systems called “Approximation Logics”. In these systems the use of a set of constants constitutes a fundamental tool. We have introduced in [8] a logic system called without this kind of constants but limited to the case that T is a finite poset. We have proved a completeness result for this system w.r.t. an algebraic semantics. We introduce in this paper a Kripke‐style semantics for a subsystem of for which there existes a deduction theorem. The set of “possible worldsr is enriched by a family of functions indexed by the elements of T and satisfying some conditions. We prove a completeness result for system with respect to this Kripke semantics and define a finite Kripke structure that characterizes the propositional fragment of logic . We introduce a reational semantics (found by E. Orlowska) which has the advantage to allow an interpretation of the propositionnal logic using only binary relations. We treat also the computational complexity of the satisfiability problem of the propositional fragment of logic .     

Physicochemical Properties and Functional Characteristics of Ecologically Extracted Shrimp Chitosans with Different Organic Acids during Demineralization Step

The current study aims to develop eco-friendly and economical chitosans with a wide range of applications using organic acids for shrimp shells demineralization. Chitosan samples were extracted from shrimp (Parapenaeus longirostris) shells and the demineralization step was performed with three organic acids (citric, acetic, and lactic) and two mineral acids (hydrochloric and sulfuric). The chitosans were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The chitosans’ physicochemical properties were also determined. The characteristic bands and functional groups of the chitosans were identified by FTIR spectra. The chitosans’ crystallinity order was as follows: Ch_HCl > Ch_Citric > Ch_H2SO4 > Ch_Lactic > Ch_Acetic. The chitosans’ morphological characteristics revealed a smooth surface and fibrous structures with pores. Chitosans extracted by organic acids showed the highest extraction yields. Ch_HCl and Ch_Citric had higher degrees of deacetylation values; 83.67% and 81.47%, respectively. The solubility was proportional to the degree of deacetylation. Furthermore, Ch_H2SO4 and Ch_Citric had lower molecular weight values; 149 kDa and 183 kDa, respectively. Organic acids are as effective as mineral acids for shrimp shells demineralization. The developed process opens up possibilities to produce chitin and chitosan in a more eco-friendly way and at a lower cost in many industrial sectors.     

Purification and Biochemical Characterization of a New Protease Inhibitor from Conyza dioscoridis with Antimicrobial,Antifungal and Cytotoxic Effects

The main objective of the current study was the extraction, purification, and biochemical characterization of a protein protease inhibitor from Conyza dioscoridis. Antimicrobial potential and cytotoxic effects were also examined. The protease inhibitor was extracted in 0.1 M phosphate buffer (pH 6–7). Then, the protease inhibitor, named PDInhibitor, was purified using ammonium sulfate precipitation followed by filtration through a Sephadex G-50 column and had an apparent molecular weight of 25 kDa. The N-terminal sequence of PDInhibitor showed a high level of identity with those of the Kunitz family. PDInhibitor was found to be active at pH values ranging from 5.0 to 11.0, with maximal activity at pH 9.0. It was also fully active at 50 °C and maintained 90% of its stability at over 55 °C. The thermostability of the PDInhibitor was clearly enhanced by CaCl₂ and sorbitol, whereas the presence of Ca²⁺ and Zn²⁺ ions, Sodium taurodeoxycholate (NaTDC), Sodium dodecyl sulfate (SDS), Dithiothreitol (DTT), and β-ME dramatically improved the inhibitory activity. A remarkable affinity of the protease inhibitor with available important therapeutic proteases (elastase and trypsin) was observed. PDInhibitor also acted as a potent inhibitor of commercial proteases from Aspergillus oryzae and of Proteinase K. The inhibitor displayed potent antimicrobial activity against gram+ and gram- bacteria and against fungal strains. Interestingly, PDInhibitor affected several human cancer cell lines, namely HCT-116, MDA-MB-231, and Lovo. Thus, it can be considered a potentially powerful therapeutic agent.     

A Switchable Catalyst Duo for Acyl Transfer Proximity Catalysis and Regulation of Substrate Selectivity

Enzymes are encoded with a gamut of information to catalyze a highly selective transformation by selecting the proper reactants from an intricate mixture of constituents. Mimicking biological machinery, two switchable catalysts with differently sized cavities and allosteric control are conceived that allow complementary size-selective acyl transfer in an on/off manner by modulating the effective local concentration of the substrates. Selective activation of one of two catalysts in a mixture of reactants of similar reactivity enabled upregulation of the desired product.