101 research outputs found
A new noninvasive method for the accurate and precise assessment of varicose vein diameters
The feasibility and reproducibility of a new ultrasonic method for the direct assessment of maximal varicose vein diameter (VVD) were evaluated. A study was also performed to demonstrate the capacity of the method to detect changes in venous diameter induced by a pharmacologic treatment. Patients with varicose vein disease were recruited. A method that allows the precise positioning of patient and transducer and performance of scans in a gel-bath was developed. Maximal VVD was recorded both in the standing and supine positions. The intraassay reproducibility was determined by replicate scans made within 15 minutes in both
positions. The interobserver variability was assessed by comparing VVDs measured during the
first phase baseline examination with those obtained during baseline examinations in the
second phase of the study. The error in reproducibility of VVD determinations was 5.3% when diameters were evaluated in the standing position and 6.4% when assessed in the supine
position. The intramethod agreement was high, with a bias between readings of 0.06 ±0.18 mm and of â0.02 ±0.19 mm, respectively, in standing and supine positions. Correlation coefficients were better than 0.99 in both positions. The method appears to be sensitive enough to detect small changes in VVDs induced by treatments. The proposed technique provides a tool of
potential valid use in the detection and in vivo monitoring of VVD changes in patients with varicose vein disease. The method offers an innovative approach to obtain a quantitative assessment of varicose vein progression and of treatment effects, thus providing a basis for epidemiologic survey
Optical Coherence Tomography Angiography to estimate early retinal blood flow changes after uncomplicated cataract surgery
Background: To investigate macular microvascular changes after uncomplicated phacoemulsification surgery according to the cataract severity grade. Methods: Retrospective, cross-sectional study involving 23 eyes of 23 patients who underwent elective cataract extraction. All patients underwent routine ophthalmologic examination, including optical coherence tomography angiography (OCTA) at baseline (preoperative visit, T0) and seven days postoperatively (T7). OCTA scans were obtained with the spectral domain system Cirrus 5000 (Carl Zeiss Meditec, Inc., Dublin, CA, USA), and 3 mm à 3 mm raster fovea-centered scans were obtained to evaluate the superficial capillary plexus (SCP) vessel density, perfusion density, and foveal avascular zone (FAZ) parameters. Results: SCP perfusion density significantly increased from 28.3 ± 5.73% to 33.74 ± 4.13% after the surgery (p < 0.001). Similarly, SCP vessel density significantly increased from 15.14 ± 3.41 mm-1 to 18.14 ± 2.57 mm-1 after surgery (p < 0.001). The mean preoperative FAZ area significantly increased from 0.27 ± 0.12 mm to 0.24 ± 0.11 mm seven days postoperatively (p = 0.008). When comparing softer and harder cataracts, no significant variations in SCP vessel density, as well as SCP perfusion density parameters and the FAZ area, perimeter, and circularity index, were noted before and after surgery. Conclusions: Macular SPC vessel density and macular SCP perfusion density increase after uncomplicated cataract surgery regardless of the cataract severity
Synchronized onset of nuclear and cell surface modifications in U937 cells during apoptosis
In this study we investigated the relationship between nuclear and cell surface modifications (i.e. blebbing, phosphatidylserine [PS] and sugar residues exposure) in a monocytic cell line, U937, during apoptosis induced by oxidative stress (1mM H2O2) or inhibition of protein synthesis (10 mg/ml puromycin). Dying cells were simultaneously observed for nuclear modifications, presence of superficial blebs and plasma membrane alterations. Morphological analysis performed by conventional fluorescence microscopy, or by transmission and scanning electron microscopy showed that the courses of nuclear and membrane alterations occured concomitantly, but the phenotype was dependent on the stage of the apoptotic process and the type of apoptogenic inducer used. The progression of apoptosis in U937 cells beyond early stages resulted in the extensive formation of blebs which concomitantly lost some typical markers of apoptosis, such as PS and sugar residues. Therefore, the modality by which the nucleus condenses, or the amount and the pattern of distribution of PS on the cell surface were, for each cell line, strictly related to the apoptogenic inducer. The morphological data reported in the present paper should lead to a more precise quantification of apoptosis by improving the detection of apoptotic cells in vivo (i.e. in tissue, organs), which is a crucial point in the evaluation of efficiency of antiproliferative drugs, such as antiblastic or immunosuppressive compounds
TOWARDS A LOW ALPHA LATTICE FOR THE ALBA STORAGE RING
Abstract A proposal of a low alpha lattice for the ALBA third generation light source is presented. Opposed to most of other machines, belonging to the same category, ALBA employs an optimized lattice making use of combined function dipoles. This has permitted a very compact design stripped out of all not strictly necessary quadrupoles resulting in a lack of flexibility. For such a reason the common approaches used in many other synchrotrons can not be directly applied to ALBA and a different strategy has to be worked out
Electrochemical Formation of Germanene: pH 4.5
Germanene is a single layer allotrope of Ge, with a honeycomb structure similar to graphene. This report concerns the electrochemical formation of germanene in a pH 4.5 solution. The studies were performed using in situ Electrochemical Scanning Tunneling Microscopy (EC-STM), voltammetry, coulometry, surface X-ray diffraction (SXRD) and Raman spectroscopy to study germanene electrodeposition on Au(111) terraces. The deposition of Ge is kinetically slow and stops after 2â3 monolayers. EC-STM revealed a honeycomb (HC) structure with a rhombic unit cell, 0.44 ± 0.02 nm on a side, very close to that predicted for germanene in the literature. Ideally the HC structure is a continuous sheet, with six Ge atoms around each hole. However, only small domains, surrounded by defects, of this structure were observed in this study. The small coherence length and multiple rotations domains made direct observation with surface X-ray diffraction difficult. Raman spectroscopy was used to investigate the multi-layer Ge deposits. A peak near 290 cm^(â1), predicted to correspond to germanene, was observed on one particular area of the sample, while the rest resembled amorphous germanium. Electrochemical studies of germanene showed limited stability when exposed to oxygen
Politische Fragmentierung und kulturelle KohÀrenz in der SpÀtantike
Der vorliegende Band bespricht mit Fallbeispielen sowohl die politisch bedingten Ausdifferenzierungen als auch die persistenten kulturellen Gemeinsamkeiten des 5. bis 6. Jhs. n. Chr.
Die jahrhundertelange politische Einheit des Imperium Romanum hatte ihren Ausdruck in einer groĂen kultu- rellen KohĂ€renz gefunden, fĂŒhrte doch die Ausrichtung auf Rom zu Vereinheitlichungen in vielen Bereichen. Daraus resultierten allgemein gĂŒltige Normen, die sich in Gemeinsamkeiten der materiellen Kultur und der Sprache Ă€uĂerten. Besonders augenfĂ€llig war die HomogenitĂ€t der bildenden Kunst. Mit der Teilung des Imperiums und der Bildung germanischer Reiche auf römischem Boden zerfiel seit den Jahrzehnten um 400 n. Chr. zwar die politische Einheit, die Vorstellung eines einheitlichen Imperiums und einer gemeinsamen Kultur dauerte jedoch an
Performance of Delta4 Phantom+ using Flattening-Filter and Flattening Filter-Free beams
EnThe goal of this study was to evaluate the performances of the new pre-treatment system Delta4 Phantom+ in terms of a stable and sensitive tool for achieving a reliable verification. Delta4+ was evaluated for verification with 6FFFMV beams using static beam arrangement. The accelerator output was monitored with the ionization chamber. The device was tested for dose-rate dependence, linearity and stability using its daily output correction. The response of Delta4+ was evaluated for energy 6FFFMV, measuring the gamma index of four Volumetric Modulated Arc Therapy (VMAT) plan. The response of Delta4+ as a function of accelerator dose rate is in agreement with the ionization chamber with a difference smaller than 0,1%. The output is constant for different MU. VMAT plan analysis show values within 98,3%-100% with a threshold of 3%-3mm, while with a threshold of 2%-2mm the values are within 93,5%-97,5%. Delta4+ is an accurate device. For all the measurements made, uncertainties below 1% were obtained.ItLo scopo di questo studio Ăš stato quello di valutare la risposta in termini di stabilitĂ e sensibilitĂ del nuovo sistema pre-trattamento Delta4 Phantom+. La risposta del sistema Ăš stato studiata utilizzando fasci di fotoni da 6MVsenza filtro di flattening (6FFFMV). L'output dell'acceleratore Ăš stato monitorato con una camera a ionizzazione. La dipendenza dal dose rate, la linearitĂ e la stabilitĂ sono state verificate utilizzando il fattore di correzione giornaliera fornito dal sistema. La risposta Ăš stata verificata su 4 piani di trattamento con tecnica VMAT. La risposta del Delta4+ al variare del dose rate Ăš in accordo con quella della camera a ionizzazione con una scarto minore dello 0.1%. La risposta al variare delle UM Ăš costante con una differenza entro lo 0.4%. L'analisi dei piani VMAT mostra valori di indice gamma per soglia 3%-3mm compresi tra 98.3%-100%, mentre per 2%-2mm i valori sono tra 93,5%-97,5%. Il Delta4+ risulta essere un sistema accurato in quanto l'incertezza ottenuta su tutte le misure non supera l'1%
The Calatabiano landslide (southern Italy): preliminary GB-InSAR monitoring data and remote 3D mapping
A simple method to help determine landslide susceptibility from spaceborne InSAR data: the Montescaglioso case study
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