Inappropriate antibiotic use leads to increased risk of antibiotic resistance and other adverse outcomes. The objectives of the study were to determine the prevalence and characteristics of antibiotic use in Egyptian hospitals to identify opportunities for quality improvement. A point prevalence survey was conducted in 18 hospitals in March 2011. A total of 3408 patients were included and 59% received at least one antibiotic, with the most significant use among persons <12 years and intensive care unit patients (p < 0.05). Third generation cephalosporin were the most commonly prescribed antibiotics (28.7% of prescriptions). Reasons for antibiotic use included treatment of community—(27%) and healthcare-associated infections (11%) and surgical (39%) and medical (23%) prophylaxis. Among surgical prophylaxis recipients, only 28% of evaluable cases received the first dose within two hours before incision and only 25% of cases received surgical prophylaxis for <24 h. The prevalence of antibiotic use in Egyptian hospitals was high with obvious targets for antimicrobial stewardship activities including provision of antibiotic prescription guidelines and optimization of surgical and medical prophylaxis practices.

No abstract

No abstract

No abstract

No abstract

High field electron spin resonance, nuclear magnetic resonance and magnetization studies addressing the ground state of the quasi two-dimensional spin-1/2 honeycomb lattice compound InCu 2/3 V 1/3 O3 are reported. Uncorrelated finite size structural domains occurring in the honeycomb planes are expected to inhibit long range magnetic order. Surprisingly, ESR data reveal the development of two collinear antiferromagnetic (AFM) sublattices below ∼ 20 K whereas NMR results show the presence of the staggered internal field. Magnetization data evidence a spin reorientation transition at ∼ 5.7 T. Quantum Monte-Carlo calculations show that switching on the coupling between the honeycomb spin planes in a finite size cluster yields a Néel-like AFM spin structure with a substantial staggered magnetization at finite temperatures. This may explain the occurrence of a robust AFM state in InCu 2/3 V 1/3 O3 despite an unfavorable effect of structural disorder.PACS numbers: 75.50. Ee, 76.30.Fc, 75.10.Jm In planar honeycomb lattice systems a combination of nontrivial topology, strong electronic, spin and orbital correlations and degeneracies yields a rich variety of ground states, novel excitations and exotic behaviors that currently attract much attention. The recently discovered exciting phenomena range, e.g., from the quantum Hall effect in graphene 1,2 , superconductivity in MgB 2 3 and intercalated graphite 4 , to topologically driven quantum phase transitions in anyonic quantum liquids 5 .Regarding the spin degrees of freedom, an important feature of low dimensional spin systems is the presence of quantum fluctuations that inhibit long range order of the quantum spin-1/2 lattice. Such an effect essentially depends on the spin coordination number z. The one dimensional (1D) Heisenberg antiferromagnetic (AFM) S = 1/2 chain with z = 2 does not show any magnetic order even at zero temperature 6 , whereas long range order is possible at T = 0 in the 2D case 7 as, e.g., in the prominent S = 1/2 Heisenberg square lattice model with z = 4. The honeycomb lattice has the minimum possible coordination number of any regular 2D lattice z = 3. Thus quantum fluctuations there are weaker than in the 1D case, but stronger than in the 2D square lattice. Hence, the AFM order for the honeycomb lattice is fragile 8,9 .Experimentally, low-D spin systems described by the Heisenberg Hamiltonian H = 2J afm S i S j are often realized in structurally three dimensional organic-or transition metal oxide (TMO) compounds where strong AFM exchange interaction J afm between unpaired localized spins occurs along only one or two spacial directions. Owing to residual small 3D exchange couplings such materials usually exhibit a long range Néel order at a finite temperature T N , though, unlike in the 3D magnets, the ordering occurs at much smaller temperaturesRecently, a complex TMO compound, InCu 2/3 V 1/3 O 3 , was suggested as a possible candidate for the realization of the S = 1/2 honeycomb lattice 10 . In its layered hexagonal structure the Cu 2+ (3d 9...

The topology of the magnetic interactions of the copper spins in the nitrosonium nitratocuprate (NO) [Cu(NO 3 ) 3 ] suggests that it could be a realization of the Nersesyan-Tsvelik model, whose ground state was argued to be either a resonating valence bond (RVB) state or a valence bond crystal (VBC). The measurement of thermodynamic and resonant properties reveals a behavior inherent to low dimensional spin S = ½ systems and provides indeed no evidence for the formation of long-range magnetic order down to 1.8 K.Low dimensional quantum magnets are currently the object of an intensive experimental and theoretical research. This stems from the rich physics which is displayed by these systems due to their reduced dimensionality and competing interactions which often push the transition to ordered states to very low temperatures or even preclude the onset of magnetism at all.Geometric frustration is one of the effects which are believed to lead to possible non-classical states. A non-classical ground state does exist in a pure one-dimensional quantum antiferromagnet which is disordered and carries low-energy spinon excitations with fractional quantum numbers. A fundamental question is whether such non classical states can survive in higher dimensions and whether they could realize the long-sought resonant valence bond (RVB) state [1]. The concept of RVB state is of utmost importance in modern condensed matter physics, not only for frustrated magnetism in general but also in the context of high -temperature superconductivity of layered cupric compounds [2].

No abstract