Oscillation of Nonlinear Differential Equations with Advanced Arguments

This paper is concerned with the oscillation of all solutions of the n-th order delay differential equation . The necessary and sufficient conditions for oscillatory solutions are obtained and other conditions for nonoscillatory solution to converge to zero are established

Exploring the coordination capabilities of a family of flexible benzotriazole-based ligands using Cobalt (II) sources

In this study we focus on the coordination chemistry of a family of three flexible benzotriazole-based ligands (L1-L3) using Cobalt(II) salts. Our efforts have resulted to the formation of ten novel compounds, formulated as [Co2(L1)2Cl4]·2MeCN (1·2MeCN), Co2(L1)2Br4 (2), [Co(L2)Cl2]·MeCN (3·MeCN), Co(L2)Cl2 (4), [Co2(L2)2Br4]·2MeCN (5·2MeCN), [Co(L2)2(NO3)2]·2MeCN (6·2MeCN), [Co2(L3)2Cl4]·2MeCN (7·2MeCN), Co2(L3)2Cl4 (8), Co2(L3)2Br4 (9), and Co(L3)2(NO3)2 (10). The structures have been well characterised through X-Ray crystallography, FT-IR, ESI-MS, PXRD, Elemental Analysis and TGA studies. The compounds show a large structural variety depending on synthetic parameters (ratio, temperature and metal salt) and the ligand selection (various conformations in each ligand). When tuned appropriately, these factors drastically affect dimensionality, metal geometry and the nuclearity of the final product, resulting in a range of 0D dimers (1, 3, 5, 8, 9), 1D (2, 7, 10) and 2D (4, 6) coordination polymers (CPs). A temperature-induced single-crystal to single-crystal transformation of compound 3 to 4 is additionally reported. The magnetic properties of representative compounds (4, 7, 9) are subject to large changes with only minor structural variations, suggesting that tetrahedral Co(II) nodes in CPs or MOFs could function as sensitive reporters of small changes in the local environment

Prophylactic Ketamine Reduces Incidence of Postanaesthetic Shivering

General anesthesia influences the thermoregulatory process. The aim of this study was to compare the efficacy of low-dose prophylactic ketamine with that ofplacebo in preventing postoperative shivering. A prospective randomized double-blind study involved 76 ASA I and II patients undergoing general anesthesia that was expected to last no more than 2 hours. Patientswere randomly allocated to receive normal saline (Group P, n=33) or ketamine 0.5 mg kg (Group K, n=33) intravenously 20 min before completion of surgery. The anesthesia was induced with propofol 2.5-3.0 mgkg and fentanyl (2 -3 μgkg ), atracurium 0.5 mgkg ) was given to facilitateorotracheal intubation. It was maintained with propofol (510 mgkg hr ), fentanylup to (5 μg · kg · h and a mixture of nitrous oxide/oxygen (2:1). Ambient temperature was maintained at 20°22°C with constant humidity. Postoperative shivering in the recovery room was evaluated according to 5 point scale ofWrench. The two groups did not differ significantly regarding patient characteristics. The number of patients shivering onarrival in the recovery room, and at 10 and 20 min after operationwas significantly less in Groups K than in Group P. In group P 36% have had shivering in T0 whereas in group K 6%, in T10 45% in group P whereas 18% in group K. In T 20 24% in group Phave had shivering compared with6%in group K, whereas in T309%in group P compared with 0% in group K. The incidence of free Postanaesthetic shivering (no shivering) on arrival in the recovery room T0 was: 63.6% in group P compared with 90.9 % in group K. The postoperative hemodynamic parameters were similar in the two groups. Active warming was not required in group K but was needed in 8 cases in group P. None of patients had episodes of O desaturation or respiratory depression during the study period. No hallucinations, delirium, nausea, vomiting, hypertension, tachycardia, and feeling like walking in the space or nystagmus were seen in any of the patients. Prophylactic low-dose ketamine was found to be effectivein preventing postoperative shivering.

Cu(II) coordination polymers as vehicles in the A³ coupling

A family of benzotriazole based coordination compounds, obtained in two steps and good yields from commercially available materials, formulated [CuII(L 1 )2(MeCN)2]·2(ClO4)·MeCN (1), [CuII(L 1 )(NO3)2]·MeCN (2), [ZnII(L 1 )2(H2O)2]·2(ClO4)·2MeCN (3), [CuII (L 1 )2Cl2]2 (4), [CuII 5(L 1 )2Cl10] (5), [CuII 2(L 1 )4Br2]·4MeCN·(CuII 2Br6) (6), [CuII(L 1 )2(MeCN)2]·2(BF4) (7), [CuII(L 1 )2(CF3SO3)2] (8), [ZnII(L 1 )2(MeCN)2]·2(CF3SO3) (9), [CuII 2(L 2 )4(H2O)2]·4(CF3SO3)·4Me2CO (10) and [CuII 2(L 3 )4(CF3SO3)2]·2(CF3SO3)·Me2CO (11) are reported. These air stable compounds were tested as homogeneous catalysts for the A3 coupling synthesis of propargyl amine derivatives from aldehyde, amine and alkyne under a non-inert atmosphere. Fine-tuning of the catalyst resulted in a one dimensional (1D) coordination polymer (CP) (8) with excellent catalytic activity in a wide range of substrates, avoiding any issues that would inhibit its performance

Diffusion behavior of transition metals in field-assisted ion-exchanged glasses

The use of ion-exchange techniques for doping silicate glasses with transition metals has attracted much attention in the last decades for its potential in several applications, namely, light waveguides technology, luminescent materials, and for the possibility to realize systems in which metal nanocluster formation is controlled by suitable post-exchange techniques. In this framework, the control of metal distribution inside the glass is a central issue for both the understanding of the incorporation process and for the definition of effective preparation protocols. In this experiment, metallic films (Ag, Cu, Au, Co) were deposited onto the substrates by the rf-sputtering technique. Metal ions then penetrate to substitute glass alkali by means of field-assisted ion-exchange, realized at different temperature and electric field values. In particular, we present in this paper the Au doping of silicate glasses, successfully realized for the first time with this method. The gold diffusion profiles, as measured by Secondary Ion Mass Spectrometry (SIMS), indicate that the migration depends on the experimental parameters (temperature and electric field), but also on the local structure, as well as on chemical phenomena occurring at the metal/glass interface

COPPER DIFFUSION IN ION-EXCHANGED SODA-LIME GLASS

Cu-alkali ion exchange in silicate glasses gives rise to a peculiar copper distribution, with the presence of both the Cu2+ and Cu+ oxidation states. Grazing incidence X-ray absorption near-edge structure spectroscopy and secondary ion mass spectrometry were performed on different ion-exchanged samples. The results show that the Cu2+/Cu+ ratio is strongly depth-dependent. The relative presence of the two species throughout the exchanged region turns out to be governed by their different diffusion regimes, while the chemistry of the redox process is shown to play a minor role. A phenomenological model is proposed to describe the diffusion process