ABSTRACT
We use ab initio real-time time-dependent density functional theory to investigate the effect of optical and extreme ultraviolet (XUV) circularly polarized femtosecond pulses on the magnetization dynamics of ferromagnetic materials. We demonstrate that the light induces a helicity-dependent reduction of the magnitude of the magnetization. In the XUV regime, where the 3p semicore states are involved, a larger helicity dependence persisting even after the passage of light is exhibited. Finally, we were able to separate the part of the helicity-dependent dynamics due to the absorption from the part due to the inverse Faraday effect. Doing so, we show that the former has, overall, a greater impact on the magnetization than the latter, especially after the pulse and in the XUV regime. This work hints at the yet experimentally unexplored territory of the XUV light-induced helicity-dependent dynamics, which, according to our prediction, could magnify the helicity-dependent dynamics already exhibited in the optical regime.
ABSTRACT
Clusters, i.e. polyhedral geometric entities, are widely used to describe the structure of complex intermetallic compounds. However, little is generally known about their physical significance. The atomic and electronic structures of the Al13TM4 complex intermetallic compounds (TM = Fe, Co, Ru, Rh) have been investigated using a wide range of ab initio tools in order to examine the influence of the chemical composition on the pertinence of the bulk structure description based on 3D clusters. In addition, since surface studies were found to be a relevant approach to address the question of cluster stability in complex phases, the interplay of the cluster substructure with the 2D surface is addressed in the case of the Al13Co4(100) and Al13Fe4(010) surfaces.
ABSTRACT
The present multicenter, randomized crossover study compared the safety and efficacy of continuous infusion with those of short infusions of ceftazidime in patients with cystic fibrosis. Patients with chronic Pseudomonas aeruginosa colonization received two successive courses of intravenous tobramycin and ceftazidime (200 mg/kg of body weight/day) for pulmonary exacerbation administered as thrice-daily short infusions or as a continuous infusion. The primary endpoint was the variation in the forced expiratory volume in 1 s (FEV1) during the course of antibiotic treatment. Sixty-nine of the 70 patients enrolled in the study received at least one course of antibiotic treatment. The improvement in FEV1 at the end of therapy was not statistically different between the two treatment procedures (+7.6% after continuous infusion and +5.5% after short infusions) but was better after continuous ceftazidime treatment in patients harboring resistant isolates (P < 0.05). The interval between the course of antibiotic treatments was longer after the continuous infusion than after the short infusion of ceftazidime (P = 0.04). The mean serum ceftazidime concentration during the continuous infusion was 56.2 +/- 23.2 microg/ml; the mean peak and trough concentrations during the short infusions were 216.3 +/- 71.5 and 12.1 +/- 8.7 microg/ml, respectively. The susceptibility profiles of the P. aeruginosa isolates remained unchanged and were similar for both regimens. Quality-of-life scores were similar whatever the treatment procedure, but 82% of the patients preferred the continuous-infusion regimen. Adverse events were not significantly different between the two regimens. In conclusion, the continuous infusion of ceftazidime did not increase its toxicity and appeared to be as efficient as short infusions in patients with cystic fibrosis as a whole, but it gave better results in patients harboring resistant isolates of P. aeruginosa.
Subject(s)
Anti-Bacterial Agents/administration & dosage , Ceftazidime/administration & dosage , Cystic Fibrosis/drug therapy , Adolescent , Adult , Anti-Bacterial Agents/adverse effects , Ceftazidime/adverse effects , Cross-Over Studies , Drug Administration Schedule , Female , Humans , Male , Young AdultABSTRACT
A prerequisite to the developement of an efficient cell and/or gene therapy for lung cancer is a precise characterization of the inflammatory cell populations spontaneously present in the tumor stroma associated with this cancer. This study was designed to define the cytotoxic potential and the relationship with stroma development of tumor infiltrating lymphocytes (TIL) and tumor associated macrophages (TAM). Tumor samples from 48 patients undergoing surgery for non-small cell lung cancer (NSCLC) were analyzed, by immunohistochemistry and in situ hybridization, with a panel of antibodies and probes specific for cell proteins linked to cytotoxicity, cytokines, and growth factors, and the replication status of TIL and TAM was evaluated by in vivo 5-bromodeoxyuridine incorporation. It was shown that, in NSCLC: (1) tumor stroma inflammatory cells are mainly TIL (approximately 2/3) (among them, 80 % are T-cells) and TAM (approximately 1/3), with almost no natural killer (NK) cells, and a few dentritic cells; (2) TAM and TIL are poorly replicating, but mainly recruited to the tumor stroma; (3) more than half TAM show an antibody-dependent cytotoxic potential, and one third of T-cells are TIA-1 positive CD8 activated cytotoxic lymphocytes; (4) cancer cells from only a few tumor express HLA class I and II antigens; (5) TAM production of cytotoxic cytokines [interleukin-1alpha (IL-1alpha), IL-1beta, IL-6, tumor necrosis factor-alpha (TNF-alpha)] and of transforming growth factor-beta1 (TGF-beta1) is low, in contrast to their strong release of platelet-derived growth factor (PDGF). We concluded that, in NSCLC, TIL cytotoxicity is likely to be low because of a poor class I MHC expression by tumor cells, and TAM low production of cytotoxic cytokines is a major limit to their possible cytotoxic activity. In contrast, TAM may favor tumor progression by contributing to tumor stroma formation and angiogenesis through their release of PDGF, in conjunction with TGF-beta1 production by tumor cells.
