Stability in nonlinear neutral differential equations with variable delays using fixed point theory

The purpose of this paper is to use a fixed point approach to obtain asymptotic stability results of a nonlinear neutral differential equation with variable delays. An asymptotic stability theorem with a necessary and sufficient condition is proved. In our consideration we allow the coefficient functions to change sign and do not require bounded delays. The obtained results improve and generalize those due to Burton, Zhang and Raffoul. We end by giving three examples to illustrate our work

Staphylococcal cassette chromosome mec typing and meca sequencing in methicillin-resistant staphylococci from Algeria: A highly diversified element with new mutations in mecA

Genetic mechanisms of methicillin resistance are still relevant in staphylococci. The aims of this study are to assess the possible exchanges of staphylococcal cassette chromosome mec (SCCmec) among isolates of methicillin-resistant staphylococci (MRS) and to check for known or new mutations in mecA DNA. A total of 35 MRS non-repetitive isolates were recovered, including 20 Staphylococcus haemolyticus, 7 Staphylococcus aureus, 4 Staphylococcus sciuri, 2 Staphylococcus saprophyticus and 1 isolate each of Staphylococcus xylosus and Staphylococcus lentus. Only 16 of the 35 strains were assigned to known SCCmec types: 7 SCCmec VII, 6 SCCmec IV and 3 SCCmec III, with possible horizontal transfer of the SCCmec VII from methicillin-resistant S. haemolyticus to methicillin-susceptible S. aureus. mecA gene sequencing in ten selected isolates allowed description of nine punctual mutations, seven of which were reported for the first time. The most frequent mutation was G246E, identified in isolates of methicillin-resistant S. aureus, S. sciuri, S. saprophyticus and S. lentus. These results emphasized the high degree of genetic diversity of SCCmec element in MRS and describe new missense mutations in mecA, which might be important in understanding the evolution of methicillin and new b-lactam resistance

Common fixed point theorems for single and set-valued maps satisfying a strict contractive condition

Some new common fixed point theorems for weakly compatible single and set-valued mappings under strict contractive conditions are obtained. Our results extend, improve and complement the result of Fisher [3] and the recent one due to Ahmed [2] and others

Anticonvulsant Activity of Hydroalcoholic Extract of Ageratum Conyzoides L. (Asteraceae) in Mice

This work aimsto study the anticonvulsant activity in vivo of the hydro alcoholic extract of Ageratum conyzoides L. (ASTERACEAE) in mice. Seizure was induced by electric stimulation of animal ears and intraperitoneal injection of picrotoxin. The extract increases the seizure threshold and reduces picrotoxin-induced convulsion duration. Animals of control group reacted to electric shock of 10.67 ± 0.74 mV, versus 14.33 ± 0.64, 22.67 ± 1.28 and 29.33 ± 0.64 mV for the animals treated with the extract at doses 200, 400 and 800 mg/kg respectively (P<0.05). Duration of clonic seizure induced by picrotoxin decreases from 36.04 ± 3.46 s in control group to 31.33 ± 0.88, 14.08 ± 1.02 and 10.07 ±1.31 s in the treated animals, while tonic seizure duration in control group is equal to 156.33 ± 24.53 s versus 73.02 ± 5.32 s and 29.67 ± 3.59 s in the animals treated with the extract at doses 400 and 800 mg/kg respectively (P<0.05). Alkaloids in the extract might be responsible for this activity by blocking Na+ or K+ channels, it also might enhance GABA or inhibit glutamate action

Common fixed point theorems for pairs of single and multivalued D-maps satisfying an integral type

This contribution is a continuation of [1, 3, 14]. The concept of subcom- patibility between single maps and between single and multivalued maps is used as a tool for proving existence and uniqueness of common fixed points on complete metric and symmetric spaces. Extensions of known results, in particularly results given by Djoudi and Aliouche, Elamrani and Mehdaoui, Pathak et al. are thereby obtained

Descriptive Epidemiology of Nasal Carriage of Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus Among Patients Admitted to Two Healthcare Facilities in Algeria

Aim: To evaluate nasal carriage rate and variables associated with Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) in patients admitted in two healthcare facilities. Results: S. aureus was isolated from 159 (26%) of the enrolled patients. Methicillin-susceptible S. aureus was isolated from 150 (24.5%) patients, and MRSA was isolated from 9 (1.5%). Cancer and previous hospitalization were associated with a significantly higher frequency of nasal S. aureus carriage among the patients admitted to the general hospital and the nephrology department, respectively. MRSA isolates were heterogeneous with respect to their staphylococcal cassette chromosome mec element (SCCmec) type, sequence type (ST), and toxin genes (pvl and tst1) content. Four isolates were attributed with the ST80-MRSA-IV clone, which is known to be predominant in Algeria. Conclusions: This is the first assessment of S. aureus and MRSA nasal carriage and associated variables in Algeria. Our findings provide also a picture of the MRSA strains circulating in the community in this geographic area. They can be useful as a guide for implementing screening and control procedures against S. aureus/MRSA in the Algerian healthcare facilities

Hyaluronic Acid Scaffolds for Loco-Regional Therapy in Nervous System Related Disorders

Hyaluronic acid (HA) is a Glycosaminoglycan made of disaccharide units containing N-acetyl-D-glucosamine and glucuronic acid. Its molecular mass can reach 10 MDa and its physiological properties depend on its polymeric property, polyelectrolyte feature and viscous nature. HA is a ubiquitous compound found in almost all biological tissues and fluids. So far, HA grades are produced by biotechnology processes, while in the human organism it is a major component of the extracellular matrix (ECM) in brain tissue, synovial fluid, vitreous humor, cartilage and skin. Indeed, HA is capable of forming hydrogels, polymer crosslinked networks that are very hygroscopic. Based on these considerations, we propose an overview of HA-based scaffolds developed for brain cancer treatment, central and peripheral nervous systems, discuss their relevance and identify the most successful developed systems

Finite-Size Effects and Scaling for the Thermal QCD Deconfinement Phase Transition within the Exact Color-Singlet Partition Function

We study the finite-size effects for the thermal QCD Deconfinement Phase Transition (DPT), and use a numerical finite size scaling analysis to extract the scaling exponents characterizing its scaling behavior when approaching the thermodynamic limit. For this, we use a simple model of coexistence of hadronic gas and color-singlet Quark Gluon Plasma (QGP) phases in a finite volume. The Color-Singlet Partition Function (CSPF) of the QGP cannot be exactly calculated and is usually derived within the saddle point approximation. When we try to do calculations with such an approximate CSPF, a problem arises in the limit of small temperatures and/or volumes (VT3<<1), requiring then additional approximations if we want to carry out calculations. We propose in this work a new method for an accurate calculation of any quantity of the finite system, without explicitly calculating the CSPF itself and without any approximation. By probing the behavior of some useful thermodynamic response functions on the hole range of temperature, it turns out that in a finite size system, all singularities in the thermodynamic limit are smeared out and the transition point is shifted away. A numerical finite size scaling analysis of the obtained data allows us to determine the scaling exponents of the QCD DPT. Our results expressing the equality between their values and the space dimensionality is a consequence of the singularity characterizing a first order phase transition and agree very well with the predictions of other FSS theoretical approaches and with the results of both lattice QCD and Monte Carlo models calculations.Comment: 09 pages, 11 Postscript figure