Raul Fernandez

Bio: Raul Fernandez is an academic researcher from University of Chicago. The author has contributed to research in topics: Computer science & Data discovery. The author has an hindex of 36, co-authored 102 publications receiving 11567 citations. Previous affiliations of Raul Fernandez include Spanish National Research Council & University of Texas at Austin.

WSXM: a software for scanning probe microscopy and a tool for nanotechnology.

Abstract: In this work we briefly describe the most relevant features of WSXM, a freeware scanning probe microscopy software based on MS-Windows. The article is structured in three different sections: The introduction is a perspective on the importance of software on scanning probe microscopy. The second section is devoted to describe the general structure of the application; in this section the capabilities of WSXM to read third party files are stressed. Finally, a detailed discussion of some relevant procedures of the software is carried out.

Devices for use in transluminal and endoluminal surgery

Abstract: The present invention is a device and method of using a variety of laparoscopic or NOTES surgical tools at a confined or inaccessible space, e.g., an intra-abdominal surgical and NOTES tool inserted through a single incision through the skin or hollow viscus. Generally, the laparoscopic or NOTES surgical devices include a device body having a first side and a second side, wherein the first side includes a positioning mechanism and the second side includes one or more of a variety of laparoscopic or NOTES tools.

Integrating scale out and fault tolerance in stream processing using operator state management

Abstract: As users of "big data" applications expect fresh results, we witness a new breed of stream processing systems (SPS) that are designed to scale to large numbers of cloud-hosted machines. Such systems face new challenges: (i) to benefit from the "pay-as-you-go" model of cloud computing, they must scale out on demand, acquiring additional virtual machines (VMs) and parallelising operators when the workload increases; (ii) failures are common with deployments on hundreds of VMs-systems must be fault-tolerant with fast recovery times, yet low per-machine overheads. An open question is how to achieve these two goals when stream queries include stateful operators, which must be scaled out and recovered without affecting query results.Our key idea is to expose internal operator state explicitly to the SPS through a set of state management primitives. Based on them, we describe an integrated approach for dynamic scale out and recovery of stateful operators. Externalised operator state is checkpointed periodically by the SPS and backed up to upstream VMs. The SPS identifies individual operator bottlenecks and automatically scales them out by allocating new VMs and partitioning the checkpointed state. At any point, failed operators are recovered by restoring checkpointed state on a new VM and replaying unprocessed tuples. We evaluate this approach with the Linear Road Benchmark on the Amazon EC2 cloud platform and show that it can scale automatically to a load factor of L=350 with 50 VMs, while recovering quickly from failures.

Trocar-less instrumentation for laparoscopy: magnetic positioning of intra-abdominal camera and retractor.

Abstract: Laparoscopic surgery is an increasingly common method to treat surgical disease. However, hand-eye dissociation, a two-dimensional field-of-view, and fixed instrumentation with limited degrees of freedom contribute to a steep learning curve.1–3 Another significant limitation of laparoscopy is the fixed working envelope surrounding each port that is created by the fulcrum motion around the insertion point of each trocar. This often necessitates placement of multiple ports to accommodate changes in instrument position for improved visibility and efficiency. Additional ports contribute to postoperative pain, diminish cosmesis, and carry a risk of bleeding, hernia formation, or organ damage.4,5 Current robotic systems can overcome some of these hurdles, but they still require multiple trocars and are restricted by even smaller working envelopes.6 To provide greater flexibility of endoscopic viewing, instrument usage and to further reduce morbidity, we have developed in prototype a novel adjunct laparoscopic system concept, a moveable, “lockable” platform that is positioned intra-abdominally and stabilized by an external permanent magnet placed on the abdominal skin. Our hypothesis is that a transabdominal “magnetic anchoring and guidance system” (MAGS) can be used to actively control an intra-abdominal endoscope and multiple working instruments introduced through a single trocar into the abdominal cavity (Fig. 1). This platform would allow unrestricted intra-abdominal movement of surgical instruments and has the potential to realize the benefits of single-keyhole surgery while meeting or exceeding the performance of current-day fixed-trocar laparoscopy. We present the initial development of a MAGS camera and tissue retractor for laparoscopic surgery. FIGURE 1. A, Schematic representation of conventional transabdominal trocar and instrument (left) and proposed magnetically anchored and guided instrument/camera (right). B, Schematic representation of typical multitrocar laparoscopic surgery (left) and ...

Biologically active APRIL is secreted following intracellular processing in the Golgi apparatus by furin convertase

Abstract: Tumor necrosis factor (TNF) ligand family members are synthesized as transmembrane proteins, and cleavage of the membrane-anchored proteins from the cell surface is frequently observed. The TNF-related ligands APRIL and BLyS and their cognate receptors BCMA/TACI form a two ligand/two receptor system that has been shown to participate in B- and T-cell stimulation. In contrast to BLyS, which is known to be cleaved from the cell surface, we found that APRIL is processed intracellularly by furin convertase. Blockage of protein transport from the endoplasmic reticulum to the Golgi apparatus by Brefeldin A treatment abrogated APRIL processing, whereas monensin, an inhibitor of post-Golgi transport, did not interfere with cleavage of APRIL, but blocked secretion of processed APRIL. Thus, APRIL shows a unique maturation pathway among the TNF ligand family members, as it not detectable as a membrane-anchored protein at the cell surface, but is processed in the Golgi apparatus prior to its secretion.

Gwyddion: an open-source software for SPM data analysis

Abstract: In this article, we review special features of Gwyddion—a modular, multiplatform, open-source software for scanning probe microscopy data processing, which is available at http://gwyddion.net/. We describe its architecture with emphasis on modularity and easy integration of the provided algorithms into other software. Special functionalities, such as data processing from non-rectangular areas, grain and particle analysis, and metrology support are discussed as well. It is shown that on the basis of open-source software development, a fully functional software package can be created that covers the needs of a large part of the scanning probe microscopy user community.

Electronic Transport Properties of Individual Chemically Reduced Graphene Oxide Sheets

Abstract: Individual graphene oxide sheets subjected to chemical reduction were electrically characterized as a function of temperature and external electric fields. The fully reduced monolayers exhibited conductivities ranging between 0.05 and 2 S/cm and field effect mobilities of 2−200 cm2/Vs at room temperature. Temperature-dependent electrical measurements and Raman spectroscopic investigations suggest that charge transport occurs via variable range hopping between intact graphene islands with sizes on the order of several nanometers. Furthermore, the comparative study of multilayered sheets revealed that the conductivity of the undermost layer is reduced by a factor of more than 2 as a consequence of the interaction with the Si/SiO2 substrate.

Display screen or portion thereof with graphical user interface

Abstract: Newness and distinctiveness is claimed in the features of ornamentation as shown inside the broken line circle in the accompanying representation.

Surgical stapling instrument with an articulatable end effector

Abstract: A surgical instrument can comprise a channel configured to support a staple cartridge and, in addition, an anvil pivotable between open and closed positions relative to the channel. The surgical instrument can further comprise a cutting member configured to incise tissue positioned captured between the staple cartridge and the anvil and, in addition, means for stopping the cutting member prior to a distal end datum, wherein the distal end datum can be defined by the distal-most staple cavity in the staple cartridge. In such embodiments, the incision within the tissue may not extend beyond the portion of the tissue that has been stapled.

Giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor

Abstract: Two-dimensional (2D) transition metal dichalcogenides (TMDs) are emerging as a new platform for exploring 2D semiconductor physics. Reduced screening in two dimensions results in markedly enhanced electron-electron interactions, which have been predicted to generate giant bandgap renormalization and excitonic effects. Here we present a rigorous experimental observation of extraordinarily large exciton binding energy in a 2D semiconducting TMD. We determine the single-particle electronic bandgap of single-layer MoSe2 by means of scanning tunnelling spectroscopy (STS), as well as the two-particle exciton transition energy using photoluminescence (PL) spectroscopy. These yield an exciton binding energy of 0.55 eV for monolayer MoSe2 on graphene—orders of magnitude larger than what is seen in conventional 3D semiconductors and significantly higher than what we see for MoSe2 monolayers in more highly screening environments. This finding is corroborated by our ab initio GW and Bethe-Salpeter equation calculations which include electron correlation effects. The renormalized bandgap and large exciton binding observed here will have a profound impact on electronic and optoelectronic device technologies based on single-layer semiconducting TMDs.