University of Crete

About: University of Crete is a education organization based out in Rethymno, Greece. It is known for research contribution in the topics: Population & Galaxy. The organization has 8681 authors who have published 21684 publications receiving 709078 citations. The organization is also known as: Panepistimio Kritis.

Occupational Exposure from Common Fluoroscopic Projections Used in Orthopaedic Surgery

Abstract: Background: Personnel assisting in or performing fluoroscopically guided procedures may be exposed to high doses of radiation. Accurate occupational dosimetric data for the orthopaedic theater staff are of paramount importance for practicing radiation safety. Methods: Fluoroscopic screening was performed on an anthropomorphic phantom with use of four projections common in image-guided orthopaedic surgery. The simulated projections were categorized, according to the imaged anatomic area and the beam orientation, as (1) hip joint posterior-anterior, (2) hip joint lateral cross-table 45°, (3) lumbar spine anterior-posterior, and (4) lumbar spine lateral 90°. The scattered air kerma rate was measured on a grid surrounding the operating table. For each grid point, the effective dose, eye lens dose, and face skin dose values, normalized over the tube dose area product, were derived. For the effective dose calculations, three radiation protection conditions were considered: (1) with the exposed personnel using no protection measures, (2) with the exposed personnel wearing a 0.5-mm lead-equivalent protective apron, and (3) with the exposed personnel wearing both an apron and a thyroid collar. Maximum permissible workloads for typical hip, spine, and kyphoplasty procedures were derived on the basis of compliance with effective dose, eye lens dose, and skin dose limits. Results: We found that the effective dose, eye lens dose, and face skin dose to an orthopaedic surgeon wearing a 0.5-mm lead-equivalent apron will not exceed the corresponding limits if the dose area product of the fluoroscopically guided procedure is <0.38 Gy m 2. When protective eye goggles are also worn, the maximum permissible dose area product increases to 0.70 Gy m 2, while the additional use of a thyroid shield allows a workload of 1.20 Gy m 2. The effective dose to the orthopaedic surgeon working tableside during a typical hip, spine, kyphoplasty procedure was 5.1, 21, and 250 μSv, respectively, when a 0.5-mm lead-equivalent apron alone was used. The additional use of a thyroid shield reduced the effective dose to 2.4, 8.4, and 96 μSv per typical hip, spine, and kyphoplasty procedure, respectively. Conclusions: The levels of occupational exposure vary considerably with the type of fluoroscopically assisted procedure, staff positioning, and the radiation protection measures used. The data presented in the current study will allow for accurate estimation of the occupational dose to orthopaedic theater personnel.

Semiconductor physics of organic-inorganic 2D halide perovskites.

Abstract: Achieving technologically relevant performance and stability for optoelectronics, energy conversion, photonics, spintronics and quantum devices requires creating atomically precise materials with tailored homo- and hetero-interfaces, which can form functional hierarchical assemblies. Nature employs tunable sequence chemistry to create complex architectures, which efficiently transform matter and energy, however, in contrast, the design of synthetic materials and their integration remains a long-standing challenge. Organic–inorganic two-dimensional halide perovskites (2DPKs) are organic and inorganic two-dimensional layers, which self-assemble in solution to form highly ordered periodic stacks. They exhibit a large compositional and structural phase space, which has led to novel and exciting physical properties. In this Review, we discuss the current understanding in the structure and physical properties of 2DPKs from the monolayers to assemblies, and present a comprehensive comparison with conventional semiconductors, thereby providing a broad understanding of low-dimensional semiconductors that feature complex organic–inorganic hetero-interfaces. This Review provides an overview of the current understanding of the physics of organic–inorganic two-dimensional halide perovskites.

The use of statins alone, or in combination with pioglitazone and other drugs, for the treatment of non-alcoholic fatty liver disease/non-alcoholic steatohepatitis and related cardiovascular risk. An Expert Panel Statement.

Abstract: Non-alcoholic fatty liver disease (NAFLD), the most common liver disease, is characterized by accumulation of fat (>5% of the liver tissue), in the absence of alcohol abuse or other chronic liver diseases. It is closely related to the epidemic of obesity, metabolic syndrome or type 2 diabetes mellitus (T2DM). NAFLD can cause liver inflammation and progress to non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis or hepatocellular cancer (HCC). Nevertheless, cardiovascular disease (CVD) is the most common cause of death in NAFLD/NASH patients. Current guidelines suggest the use of pioglitazone both in patients with T2DM and in those without. The use of statins, though considered safe by the guidelines, have very limited use; only 10% in high CVD risk patients are on statins by tertiary centers in the US. There are data from several animal studies, 5 post hoc analyses of prospective long-term survival studies, and 5 rather small biopsy proven NASH studies, one at baseline and on at the end of the study. All these studies provide data for biochemical and histological improvement of NAFLD/NASH with statins and in the clinical studies large reductions in CVD events in comparison with those also on statins and normal liver. Ezetimibe was also reported to improve NAFLD. Drugs currently in clinical trials seem to have potential for slowing down the evolution of NAFLD and for reducing liver- and CVD-related morbidity and mortality, but it will take time before they are ready to be used in everyday clinical practice. The suggestion of this Expert Panel is that, pending forthcoming randomized clinical trials, physicians should consider using a PPARgamma agonist, such as pioglitazone, or, statin use in those with NAFLD/NASH at high CVD or HCC risk, alone and/or preferably in combination with each other or with ezetimibe, for the primary or secondary prevention of CVD, and the avoidance of cirrhosis, liver transplantation or HCC, bearing in mind that CVD is the main cause of death in NAFLD/NASH patients.