Coherent and Dissipative Coupling in a Magnetomechanical System.

Hybrid elastic and spin waves hold promises for energy-efficient and versatile generation and detection of magnetic signals, with potentially long coherence times. Here we report on the combined elastic and magnetic dynamics in a one-dimensional magnetomechanical crystal composed of an array of magnetic nanostripes. Phononic and magnonic modes are impulsively excited by an optical ultrafast trigger and their decay is monitored by time-resolved magneto-optical Kerr effect. Complementary Brillouin light scattering measurements and micromagnetic simulations concur in a unified picture, in which the strength and degree of mixing of coherent and dissipative coupling of the quasiparticles are determined quantitatively.

Multidetection scheme for transient-grating-based spectroscopy.

Time-resolved optical spectroscopy represents an effective non-invasive approach to investigate the interplay of different degrees of freedom, which plays a key role in the development of novel functional materials. Here, we present magneto-acoustic data on Ni thin films on SiO2 as obtained by a versatile pump-probe setup that combines transient grating spectroscopy with time-resolved magnetic polarimetry. The possibility to easily switch from a pulsed to continuous wave probe allows probing of acoustic and magnetization dynamics on a broad time scale, in both transmission and reflection geometry.

Infection prevention in endoscopy practice: comparative evaluation of re-usable vs single-use endoscopic valves.

Re-usable air/water and suction valves used in endoscopes often demonstrate risk of infection. To the authors' knowledge, the safety and efficacy of re-usable and single-use valves have not been compared to date. As such, a laboratory investigation was undertaken to compare the safety and efficacy of re-usable and single-use valves at 11 Italian endoscopy sites. Safety was evaluated by analysing the rinse liquid of reprocessed re-usable valves ready for use, and efficacy was assessed based on the completion of endoscopic procedures without valve malfunction. This study found significantly lower contamination of single-use valves compared with re-usable valves (0 vs 29.1%, respectively; P=0.007) and similar efficacy (97.6 vs 98.8%, respectively; P=ns). Microbiological analysis of the rinse liquid of reprocessed re-usable valves identified various surviving micro-organisms and highlighted their potential pathogenicity. Such data suggest that sterile single-use valves may be safer than re-usable valves, and have comparable performance.

Chloride diffusivity in hardened cement paste from microscale analyses and accounting for binding effects.

The diffusion of chloride ions in hardened cement paste (HCP) under steady-state conditions and accounting for the highly heterogeneous nature of the material is investigated. The HCP microstructures are obtained through segmentation of X-ray images of real samples as well as from simulations using the cement hydration model CEMHYD3D. Moreover, the physical and chemical interactions between chloride ions and HCP phases (binding), along with their effects on the diffusive process, are explicitly taken into account. The homogenized diffusivity of the HCP is then derived through a least square homogenization technique. Comparisons between numerical results and experimental data from the literature are presented.

[Self expandable metal stent as bridge-to-surgery in acute bowel obstruction]. / Le protesi colorettali come bridge to surgery nelle occlusioni intestinali acute.

AIM: Self expandable metal stent (SEMS) can be used to relieve malignant colorectal obstruction. The stent serves as a palliative measure for high-risk patients or those with unresectable tumor on subsequent workup. For low-risk patients with resectable disease, SEMS serves as a safe and effective bridge to subsequent laparoscopic surgery. METHODS: From August 2009 to April 2012 we have treated with SEMS 39 patients, 20 of whom with palliative purpose; 19 patients are treated with SEMS for bridge to surgery, out of these patients, 8 were women, 11 men with median age of 61.4 years (range 36-81 years). Technical success, defined as a successful stent placement and deployment in the stricture site, was achieved for 39/40 patients (97.5%). The average duration of the procedure was about 60 minutes (range 15-120). RESULTS: Clinical success was achieved for all the 39 patients, 19 of these could be subjected to bowel preparation and colon resection after 25 days from the positioning. No colostomy was performed. Among patients undergoing the procedure, perforation occurred in 1 case. CONCLUSION: In summary, the colonic stent placement is a complex method that needs qualified medical-nursing team, able to solve any difficult situation, such as the severe, irregular and distal obstruction. SEMS positioning guarantees a high percentage of clinical and technical success; however it is necessary to pay attention to the risk of complications like bowel perforation.

Measurement of liver iron overload: noninvasive calibration of MRI-R2* by magnetic iron detector susceptometer.

An accurate assessment of body iron accumulation is essential for the diagnosis and therapy of iron overload in diseases such as thalassemia or hemochromatosis. Magnetic iron detector susceptometry and MRI are noninvasive techniques capable of detecting iron overload in the liver. Although the transverse relaxation rate measured by MRI can be correlated with the presence of iron, a calibration step is needed to obtain the liver iron concentration. Magnetic iron detector provides an evaluation of the iron overload in the whole liver. In this article, we describe a retrospective observational study comparing magnetic iron detector and MRI examinations performed on the same group of 97 patients with transfusional or congenital iron overload. A biopsy-free linear calibration to convert the average transverse relaxation rate in iron overload (R(2) = 0.72), or in liver iron concentration evaluated in wet tissue (R(2) = 0.68), is presented. This article also compares liver iron concentrations calculated in dry tissue using MRI and the existing biopsy calibration with liver iron concentrations evaluated in wet tissue by magnetic iron detector to obtain an estimate of the wet-to-dry conversion factor of 6.7 ± 0.8 (95% confidence level).

Erythrocyte aggregation in patients with systemic lupus erythematosus.

Systemic Lupus Erythematosus (SLE) is an autoimmune, chronic inflammatory, non-organ specific disease. SLE patients present a high prevalence of thrombotic and arteriosclerotic disease. The aim of the present work was to study the erythrocyte aggregation kinetics, and the effect of plasma factors, namely, immunoglobulin and fibrinogen concentration, as well as cell factors such as deformability and erythrocyte membrane lipid fluidity on the erythrocyte aggregation, in SLE patients and healthy controls. The results show that SLE patients red blood cells aggregate at higher rate and the aggregates size are also greater than controls due to an increase of immunoglobulin and plasma fibrinogen. The negative correlation between aggregation parameters and rigidity index could point out that the altered deformability diminishes the erythrocyte aggregation. Correlation between rigidity index and anisotropy suggests that the decrease of membrane lipid fluidity might be a cause of deformability decrease. The erythrocyte aggregation increase in these patients could induce a decreased flow that might contribute to the thromboembolic process present in SLE patients.

Total iron-overload measurement in the human liver region by the magnetic iron detector.

An accurate assessment of body iron accumulation is essential for the diagnosis and therapy of iron overload in diseases, such as hemochromatosis, thalassemia and other forms of severe anemias. The magnetic iron detector (MID) is a room-temperature susceptometer, which measures the total iron overload in the liver. Since February 2005, about 600 patients have been assessed using this device. The iron overload is obtained by calculating the difference between the measured magnetization signal of the patient and the patient's background signal. The latter is the magnetization signal that the patient would generate with normal iron content. This study presents the method for calculating the background signal of healthy volunteers and the application of the same method to patients with iron burden in order to evaluate their overload. The present MID sensitivity is 0.8 g and the reproducibility of the iron overload measurement of the same patients is lower than 0.5 g. The MID does not require calibration with liver biopsies. We correlated the MID measurements with the results of 26 biopsies (R = 0.62), 64 superconducting quantum interference device susceptometer measurements (R = 0.79), 666 serum ferritin concentration measurements (R = 0.72), and 41 MRI- R2* measurements (R = 0.71).

Association of -318 C/T and +49 A/G cytotoxic T lymphocyte antigen-4 (CTLA-4) gene polymorphisms with a clinical subset of Italian patients with systemic sclerosis.

Systemic sclerosis (SSc) is a complex and heterogeneous autoimmune disorder with a multi-factorial pathogenesis. Like other autoimmune disorders, the possible role of specific cytotoxic T lymphocyte antigen-4 (CTLA-4) gene polymorphisms in predisposing to SSc has been hypothesized, but it remains controversial. CTLA-4 promoter (-318C/T) and exon 1 (+49 A/G) polymorphisms have been analysed in 43 Italian females with SSc and in 93 unrelated matched healthy controls by a newly designed tetra-primer amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR) method. No significant association has been found with either polymorphisms.Nevertheless, SSc patients without concomitant Hashimoto's thyroiditis (HT) were carrying both the -318T allele (P = 0.031) and the +49 G allele (P = 0.076) more frequently than SSc patients with HT [defined by positivity for anti-thyroperoxidase (TPO) and anti-thyroglobulin (TGA) autoantibodies] than controls. Haplotype analysis confirms this association (P = 0.028), and suggests the predominant role of the -318T, whereas that of the +49 G, if any, seems weak. Thus, in Italian SSc patients the CTLA-4 -318C/T promoter polymorphism appears to be associated with the susceptibility to develop SSc without thyroid involvement. Larger studies are needed to confirm these findings and to clarify whether the -318C/T polymorphism is the functional responsible or whether it reflects the presence of another linked genetic element in the same chromosomal region.