A powerful computational crystallography method to study ice polymorphism

Classical Molecular Dynamics (MD) simulations are employed as a tool to investigate structural properties of ice crystals under several temperature and pressure conditions. All ice crystal phases are analyzed by means of a computational protocol based on a clustering approach following standard MD simulations. The MD simulations are performed by using a recently published classical interaction potential for oxygen and hydrogen in bulk water, derived from neutron scattering data, able to successfully describe complex phenomena such as proton hopping and bond formation/breaking. The present study demonstrates the ability of the interaction potential model to well describe most ice structures found in the phase diagram of water and to estimate the relative stability of sixteen known phases through a cluster analysis of simulated powder diagrams of polymorphs obtained from MD simulations. The proposed computational protocol is suited for automated crystal structure identification.Comment: RevTex 4.1, 7 figures - to be published in the Journal of Chemical Physic

Sinonasal angioleiomyoma with adipocyte differentiation: clinicopathologic study of 2 cases and review of the literature

Angioleiomyoma (ALM) is a benign tumor of the skin and soft tissues composed of well differentiated smooth muscle cells arranged around and among many vascular channels. Few cases have been reported in the sinonasal region, where ALM may show a variable amount of mature adipose tissue that may make hard the distinction from angiomyolipoma. We report here two cases that presented with a three- and six-month history of left nasal obstruction respectively. In both patients, clinical examination and imaging studies failed to reveal features of tuberous sclerosis complex and demonstrated a mass obliterating the nasal cavity arising from the inferior turbinate. Both masses were endoscopically excised. Pathologic analysis revealed highly vascularized tumors composed of well differentiated smooth muscle cells intermingled with a variable number of mature adipocytes. Immunostaining for melanocytic markers was negative. Based on these findings, both tumors were diagnosed as sinonasal-ALM with adipocytic differentiation. These two cases indicate that both clinical data (i.e. absence of features of tuberous sclerosis complex) and immunohistochemistry (i.e. absence of melanocytic markers) are mandatory for the recognition of sinonasal-ALM with adipocytic differentiation. The term angiomyolipoma to identify these lesions is confusing and should be abandoned

Gap solitons in a nonlinear quadratic negative index cavity

By integrating the full Maxwell's equations we predict the existence of gap solitons in a quadratic, Fabry-Perot negative index cavity. An intense, fundamental pump pulse shifts the band structure that forms when magnetic and electric plasma frequencies are different so that a weak, second harmonic pulse initially tuned inside the gap is almost entirely transmitted. The process is due cascading, which occurs far from phase matching conditions, and causes pulse compression. A nonlinear polarization spawns a dark soliton, while a nonlinear magnetization produces a bright soliton

Control of superluminal transit through a heterogeneous medium

We consider pulse propagation through a two component composite medium (metal inclusions in a dielectric host) with or without cavity mirrors. We show that a very thin slab of such a medium, under conditions of localized plasmon resonance, can lead to significant superluminality with detectable levels of transmitted pulse. A cavity containing the heterogeneous medium is shown to lead to subluminal-to-superluminal transmission depending on the volume fraction of the metal inclusions. The predictions of phase time calculations are verified by explicit calculations of the transmitted pulse shapes. We also demonstrate the independence of the phase time on system width and the volume fraction under specific conditions.Comment: 21 Pages,5 Figures (Published in Journal of Modern Optics

Sporadic high-grade malignant peripheral nerve sheath tumor of the hypoglossal nerve

Malignant tumors of peripheral nerve sheaths (MPNSTs) are rare malignant soft tissue tumors arising either from a peripheral nerve or from a pre-existing benign nerve sheath tumor. They occur most often in the context of Neurofibromatosis type-1 (NF-1) and are characterized by poor prognosis and aggressive behavior with a high rate of recurrence and distant metastases. We describe a 50-year-old woman who presented with right neck swelling, progressive dysphagia and tongue paresis. Imaging analysis revealed a mass involving the right parapharyngeal space. The tumor was excissed through a transcervical approach. At surgery, the tumor was strictly adherent to the hypoglossal nerve. Pathologic evaluation of the mass revealed a high-grade MPNST. Based on the pathological diagnosis, a clinical work-up for NF-1 was performed but it resulted negative. Occurrence of sporadic high-grade MPNST in the parapharyngeal space is rare and development from the hypoglossal nerve exceptional. As far as we know, only in two cases, both with clinical features consistent with NF1, the tumor was reported to be arised from the hypoglossal nerve

p63 isoforms regulate metabolism of cancer stem cells

p63 is an important regulator of epithelial development expressed in different variants containing (TA) or lacking (\u394N) the N-terminal transactivation domain. The different isoforms regulate stem-cell renewal and differentiation as well as cell senescence. Several studies indicate that p63 isoforms also play a role in cancer development; however, very little is known about the role played by p63 in regulating the cancer stem phenotype. Here we investigate the cellular signals regulated by TAp63 and \u394Np63 in a model of epithelial cancer stem cells. To this end, we used colon cancer stem cells, overexpressing either TAp63 or \u394Np63 isoforms, to carry out a proteomic study by chemical-labeling approach coupled to network analysis. Our results indicate that p63 is implicated in a wide range of biological processes, including metabolism. This was further investigated by a targeted strategy at both protein and metabolite levels. The overall data show that TAp63 overexpressing cells are more glycolytic-active than \u394Np63 cells, indicating that the two isoforms may regulate the key steps of glycolysis in an opposite manner. The mass-spectrometry proteomics data of the study have been deposited to the ProteomeXchange Consortium (http://proteomecentral. proteomexchange.org) via the PRIDE partner repository with data set identifiers PXD000769 and PXD000768

A graphical environment to express the semantics of control systems

We present the concept of a unified graphical environment for expressing the semantics of control systems. The graphical control system design environment in Simulink already allows engineers to insert a variety of assertions aimed the verification and validation of the control software. We propose extensions to a Simulink-like environment's annotation capabilities to include formal control system stability, performance properties and their proofs. We provide a conceptual description of a tool, that takes in a Simulink-like diagram of the control system as the input, and generates a graphically annotated control system diagram as the output. The annotations can either be inserted by the user or generated automatically by a third party control analysis software such as IQC$\beta$ or $\mu$-tool. We finally describe how the graphical representation of the system and its properties can be translated to annotated programs in a programming language used in verification and validation such as Lustre or C

Analysis of the RLMS Adaptive Beamforming Algorithm Implemented with Finite Precision

This paper studies the influence of the use of finite wordlength on the operation of the RLMS adaptive beamformingalgorithm. The convergence behavior of RLMS, based on the minimum mean square error (MSE), is analyzed for operation with finite precision. Computer simulation results verify that a wordlength of nine bits is sufficient for the RLMS algorithm to achieve performance close to that provided by full precision. The performance measures used include residual MSE, rate of convergence, error vector magnitude (EVM), and beam pattern. Based on all these measures, it is shown that the RLMS algorithm outperforms other earlier algorithms, such as least mean square (LMS), recursive least square (RLS), modified robust variable step size (MRVSS) and constrained stability LMS (CSLMS)