Multiscale Modeling of a Nanoelectromechanical Shuttle

In this article, we report a theoretical analysis of a nanoelectromechanical shuttle based on a multiscale model that combines microscopic electronic structure data with macroscopic dynamics. The microscopic part utilizes a (static) density functional description to obtain the energy levels and orbitals of the shuttling particle together with the forces acting on the particle. The macroscopic part combines stochastic charge dynamics that incorporates the microscopically evaluated tunneling rates with a Newtonian dynamics. We have applied the multiscale model to describe the shuttling of a single copper atom between two gold-like jellium electrodes. We find that energy spectrum and particle surface interaction greatly influence shuttling dynamics; in the specific example that we studied the shuttling is found to involve only charge states Q=0 and Q=+e. The system is found to exhibit two quasi-stable shuttling modes, a fundamental one and an excited one with a larger amplitude of mechanical motion, with random transitions between them.Comment: 9 pages, 9 figure

Mixed cation effect in chalcogenide glasses Rb2S-Ag2S-GeS2

Journal URL: http://prb.aps.org

Primary hepatocellular carcinoma in a patient with history of treated breast cancer: a case report with challenging diagnosis and treatment

Christoforos Kosmidis,1 Nikolaos Varsamis,1 Georgios Anthimidis,1 Sofia Baka,2 Dimitrios Valoukas,3 Triantafyllia Koletsa,4 Katerina Zarampouka,4 Georgios Koimtzis,5 Eleni Georgakoudi,6 Paul Zarogoulidis,7 Christoforos Efthymiadis1 1Department of Surgery, Interbalkan European Medical Center, Thessaloniki, Greece; 2Department of Oncology, Interbalkan European Medical Center, Thessaloniki, Greece; 3Department of Oncology, General Hospital of Ptolemaida, Ptolemaida, Greece; 4Pathology Department, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece; 5Third Surgical Department, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece; 6Aristotle University of Thessaloniki, Thessaloniki, Greece; 7Pulmonary-Oncology Unit, “Theageneio” Cancer Hospital, Thessaloniki, Greece Introduction: Breast cancer is the most common malignancy in women worldwide. Long-term survivors among patients treated for breast cancer are at a high risk for developing a second primary malignancy. Hepatocellular carcinoma is the most frequent primary hepatic malignancy and should be ruled out in breast cancer patients who are diagnosed with solitary hepatic lesions. False diagnosis may lead to inappropriate oncologic staging and treatment of the disease. Case presentation: We present the case of a 73-year-old female patient who had been treated for invasive ductal breast cancer 7 years ago and was diagnosed with a solid hepatic lesion at segments VI and VII and a small, calcified lesion at the tail of the pancreas on follow-up with an abdominal computed tomography. Oncology council decided that both lesions could be resected after determining whether they were metastatic or second primary malignancies. The patient underwent laparotomy and rapid biopsy which showed primary hepatocellular carcinoma and fibrosis of the pancreas. We performed hepatic segmentectomy (VI–VII) and cholecystectomy, while the pancreatic lesion was left intact. The postoperative course of the patient was uncomplicated and she remains disease free 2 years after the operation without any adjuvant therapy. Conclusion: All hepatic lesions detected in breast cancer patients should be evaluated with open mind and liver biopsy should be performed to get a definitive diagnosis and implement the proper treatment strategy. Keywords: breast cancer, hepatocellular cancer, second primary malignancy, rapid biopsy, microwave tissue coagulato

Analysis of the risk of a secondary displacement in conservati- vely treated paediatric distal radius metaphyseal fractures. A multicentric study

Objectives: Distal radius fractures represent one of the most fre-quent injuries in children. The treatment of choice is a closed reduction followed by immobilisation in plaster cast; the immediate recourse to osteosynthesis with Kirschner wires is only reserved for certain cases. The displacement rate reported in the literature is 21-39%. The aim of this study is to retrospectively evaluate the risk factors for a secondary displacement of metaphyseal radius fractures in a paediatric population treated in three different centres. Materials and methods: The initial treatment for all 360 patients examined was a closed reduction under general anaesthesia and im-mobilisation in an above elbow cast for 4 weeks. The pre-operative displacement, residual post-reduction displacement and possible di-splacement at 7 and 14 days of follow-up were all assessed clinically and radiographically. Results: A loss of reduction was reported in 102 cases; 51 under-went an additional reduction procedure - some followed by osteo-synthesis - while in the remaining 51 cases, the loss of reduction was acceptable in relation to the expectation of remodelling. The most statistically significant variable for the occurrence of a secondary displacement is a severe primary displacement. The association with the ulna fracture is not significantly correlated. The quality of the plaster cast is important for maintaining the reduction. There are a few things to consider as indicators for a second procedure: age, time elapsed from moment of fracture, fracture site and the absence of an acceptable reduction. Conclusions: In our experience, a reduction followed by osteo-synthesis with Kirschner wires should be considered the treatment of choice in fractures with a high risk of secondary displacement, namely those with severe initial displacement or unsatisfactory reduction

Lithium Ion Conducting Boron-Oxynitride Amorphous Thin Films: Synthesis and Molecular Structure by Infrared Spectroscopy and Density Functional Theory Modeling

Li ion containing oxynitride amorphous thin films are promising materials for electrochemical applications due to their high ionic conductivity, mechanical stability and chemical durability. Here we report on the preparation of Li boron-oxynitride (LiBON) amorphous thin films by rf sputtering of Li-diborate and Li-pyroborate targets in nitrogen atmosphere. The materials produced were subsequently studied by infrared transmittance spectroscopy assisted by density functional theory calculations using representative Li boron-oxide and boron-oxynitride clusters. The combination of experiments and calculations allows us to propose accurate vibrational assignments and to clarify the complex infrared activity of the LiBON films. Both experimental and calculated spectra show that nitrogen incorporation induces significant structural rearrangements, manifested mainly by a change in boron coordination number from four to three, and by the formation of boron–nitrogen-boron bridges. The nature of boron–nitrogen bonding depends on the composition of the sputtering target, with an exponential relationship adequately describing the dependence of B–N stretching frequency on bond length. Besides bonding to two boron atoms by covalent bonds, the nitrogen atoms interact also with Li ions by participating in their coordination sphere together with oxygen atoms. Likely, boron–nitrogen bonding in LiBON films facilitates Li ion transport due to induced charge delocalization within the boron–nitrogen-boron bridges and reduced electrostatic interaction with the Li ions

Thin film amorphous electrolytes : structure and composition by experimental and simulated infrared spectra

Ionic conducting glasses in thin film forms are promising candidates for applications in microelectronics devices such as microbatteries and microsupercapacitors. In recent years, it was shown that physicochemical properties of thin films may differ substantially from those of the target bulk materials..

A multispectroscopic structural study of lead silicate glasses over an extended range of compositions

A series of lead silicate glasses, spanning the broadest reported range of lead contents (up to 83 mol% PbO), were prepared, on which the following spectroscopic observations were made: Si-29 magic angle spinning nuclear magnetic resonance, time of flight mass spectroscopy, raman spectroscopy and fourier transform infrared spectroscopy. For bulk. splat-quenched samples, infrared results indicate that the lever rule is approximately followed until about 60 mol% PbO, though with considerable dissociation of the stoichiometric groups into silicate units with lesser and greater numbers of non-bridging oxygens. For roller-quenched samples, nuclear magnetic resonance data are consistent with a statistical distribution up to this lead concentration. Above 60 mol% PbO, added oxygen remains associated with lead to form a separate lead oxide glass network. The evidence for this comes from each of the spectroscopic techniques employed. A quantitative distribution of PbO is given. (C) 2009 Elsevier B.V. All rights reserved