2,781 research outputs found
State of the art of Lewis acid-containing zeolites: lessons from fine chemistry to new biomass transformation processes
[EN] The former synthesis of TS-1 opened new catalytic opportunities for zeolites, especially for their application as selective redox catalysts in several fine chemistry processes. Interestingly, isolated Ti species in the framework positions of hydrophobic zeolites, such as high silica zeolites, offer unique Lewis acid sites even in the presence of protic polar solvents (such as water). Following this discovery, other transition metals (such as Sn, Zr, V, Nb, among others) have been introduced in the framework positions of different hydrophobic zeolitic structures, allowing their application in new fine chemistry processes as very active and selective redox catalysts. Recently, these hydrophobic metallozeolites have been successfully applied as efficient catalysts for several biomass-transformation processes in bulk water. The acquired knowledge from the former catalytic descriptions in fine chemistry processes using hydrophobic Lewis acid-containing zeolites has been essential for their application in these novel biomass transformations. In the present review, I will describe the recent advances in the synthesis of new transition metal-containing zeolites presenting Lewis acid character, and their unique catalytic applications in both fine chemistry and novel biomass-transformations.This work has been supported by the Spanish Government-MINECO (MAT2012-37160), Consolider Ingenio 2010-Multicat, and UPV through PAID-06-11 (no. 1952). Manuel Moliner also acknowledges the "Subprograma Ramon y Cajal" for the contract RYC-2011-08972. ITQ thanks the "Program Severo Ochoa" for financial support.Moliner Marin, M. (2014). State of the art of Lewis acid-containing zeolites: lessons from fine chemistry to new biomass transformation processes. Dalton Transactions. 43:4197-4208. https://doi.org/10.1039/C3DT52293HS419742084
Push-Pull Control of Motor Output
Inhibition usually decreases input–output excitability of neurons. If, however, inhibition is coupled to excitation in a push–pull fashion, where inhibition decreases as excitation increases, neuron excitability can be increased. Although the presence of push–pull organization has been demonstrated in single cells, its functional impact on neural processing depends on its effect on the system level. We studied push–pull in the motor output stage of the feline spinal cord, a system that allows independent control of inhibitory and excitatory components. Push–pull organization was clearly present in ankle extensor motoneurons, producing increased peak-to-peak modulation of synaptic currents. The effect at the system level was equally strong. Independent control of the inhibitory component showed that the stronger the background of inhibition, the greater the peak force production. This illustrates the paradox at the heart of push–pull organization: increased force output can be achieved by increasing background inhibition to provide greater disinhibition
3D human pose estimation from depth maps using a deep combination of poses
Many real-world applications require the estimation of human body joints for
higher-level tasks as, for example, human behaviour understanding. In recent
years, depth sensors have become a popular approach to obtain three-dimensional
information. The depth maps generated by these sensors provide information that
can be employed to disambiguate the poses observed in two-dimensional images.
This work addresses the problem of 3D human pose estimation from depth maps
employing a Deep Learning approach. We propose a model, named Deep Depth Pose
(DDP), which receives a depth map containing a person and a set of predefined
3D prototype poses and returns the 3D position of the body joints of the
person. In particular, DDP is defined as a ConvNet that computes the specific
weights needed to linearly combine the prototypes for the given input. We have
thoroughly evaluated DDP on the challenging 'ITOP' and 'UBC3V' datasets, which
respectively depict realistic and synthetic samples, defining a new
state-of-the-art on them.Comment: Accepted for publication at "Journal of Visual Communication and
Image Representation
An Efficient Representation Format for Fuzzy Intervals Based on Symmetric Membership Functions
International audienceThis paper proposes a novel implementation of fuzzy arithmetics that exploits both fuzzy intervals and hardware specificities. First, we propose and evaluate the benefit of an alternative representation format to the traditional lower-upper and midpoint-radius representation formats for intervals. Thanks to the proposed formats, we show that it is possible to halve the number of operations and memory requirements compared to conventional methods. Then, we show that operations on fuzzy intervals are sensitive to hardware specificities of accelerators such as GPU. These include static rounding, memory usage, instruction level parallelism (ILP) and thread-level parallelism (TLP). We develop a library of fuzzy arithmetic operations in CUDA and C++ over several formats. The proposed library is evaluated using compute-bound and memory-bound benchmarks on Nvidia GPUs, and shows a performance gain of 2 to 20 over traditional approaches
Direct synthesis of a titanosilicate molecular sieve containing large and medium pores in its structure
[EN] The direct synthesis of the titanosilicate form of ITQ-39 is reported. This is the first description of the direct preparation of a titanosilicate molecular sieve containing large and medium pores in the same structure. The characterization clearly indicates the presence of Ti atoms in tetrahedral coordination in the framework of ITQ-39 zeolite. This material is very active in the oxidation of lineal and cyclic olefins with H2O2, showing selectivities between TS-1 and Ti-Beta. (C) 2012 Elsevier Inc. All rights reserved.Financial support by the Spanish MEC (Consolider Ingenio 2010-Multicat), Generalitat Valenciana by the PROMETEO program and UPV through PAID-06-11 (n.1952) is acknowledged. Manuel Moliner acknowledges to "Subprograma Ramon y Cajal" for the contract RYC-2011-08972. Jose Gaona is also acknowledged for technical help.Moliner Marin, M.; Corma Canós, A. (2012). Direct synthesis of a titanosilicate molecular sieve containing large and medium pores in its structure. Microporous and Mesoporous Materials. 164:44-48. https://doi.org/10.1016/j.micromeso.2012.06.035S444816
Cellular senescence enhances adaptive anticancer immunosurveillance
Cancer therapy often induces senescence in some cancer cells. Senescent cells, due to their profoundly altered biology, may conceivably interact with the adaptive immune system in novel ways that may boost cancer immunosurveillance, triggering the clearance of both senescent and non-senescent neoplastic cells. In this regard, we have recently reported that senescent cancer cells exhibit potent antigenicity and adjuvanticity and can elicit strong CD8(+) T cell-dependent anticancer effects when used as vaccination agents
Advances in the synthesis of titanosilicates: From the medium pore TS-1 zeolite to highly-accessible ordered materials
[EN] In the present review, we would like to cover the most fundamental advances achieved in the design of ordered titanosilicates since the earlier discovery of TS-1 reported by EniChem in the mid-eighties. The invention of the medium-pore TS-1 zeolite was a breakthrough, and this material has been applied as efficient catalyst in diverse industrial applications. However, its limited pore size (5 5.5 Å) offers diffusion limitations when working with large molecules. The design and preparation of open titanosilicates, such as large pore molecular sieves, mesoporous ordered materials, or layered-type zeolites will be described. The applicability of these titanosilicates to catalytic oxidation processes requiring bulky organic molecules will also be presented.This work has been supported by the Spanish GovernmentMINECO (MAT2012-37160), Consolider Ingenio 2010-Multicat,
and UPV through PAID-06-11 (n.1952). Manuel Moliner also acknowledges to ‘‘Subprograma Ramon y Cajal’’ for the contract
RYC-2011-08972. ITQ thanks the ‘‘Program Severo Ochoa’’ for financial support (SEV 2012 0267).Moliner Marin, M.; Corma Canós, A. (2014). Advances in the synthesis of titanosilicates: From the medium pore TS-1 zeolite to highly-accessible ordered materials. Microporous and Mesoporous Materials. 189:31-40. https://doi.org/10.1016/j.micromeso.2013.08.003S314018
Efficient Transport Protocol for Networked Haptics Applications
The performance of haptic application is highly sensitive to communication delays and losses of data. It implies several constraints in developing networked haptic applications. This paper describes a new internet protocol called Efficient Transport Protocol (ETP), which aims at developing distributed interactive applications. TCP and UDP are transport protocols commonly used in any kind of networked communication, but they are not focused on real time application. This new protocol is focused on reducing roundtrip time (RTT) and inter packet gap (IPG). ETP is, therefore, optimized for interactive applications which are based on processes that are continuously exchanging data.ETP protocol is based on a state machine that decides the best strategies for optimizing RTT and IPG. Experiments have been carried out in order to compare this new protocol and UDP
Applying Rotordynamics Analysis to Identify the Cause of High Synchronous Vibration on Overhung-Rotor Compressor
Case Stud
Practical Uses Of Advanced Rotordynamics Tools To Ensure Trouble-Free Operation Of A Gearbox.
Case StudyThe intent of this case study is to illustrate how rotor dynamics analysis can become an effective tool to improve rotor stability. Analytical method, such as undamped planar critical speed map is used to evaluate the vibration characteristics of a gearbox. Currently, advanced rotor dynamics software provides greater capability in generating and analyzing rotor models. By removing undesirable instability sources and ensuring reliable separation margin, successful rotor-stability improvement is validated. This case illustrates a rotor dynamics analysis applied on a high speed pinion of a speed increasing gearbox, which was exhibiting high vibration during operation. Analytical results predicted rotor instability due to the coincidence of the seven times operating speed and its fourth natural planar frequency. Based on recent investigation, this phenomenon is inherent to gear design, and can be controlled by adding or removing weight on the non-drive end of the high speed pinion without major modifications on the gearbox. Thanks to the rotor dynamics analysis model, the cause of the vibration was found and the gearbox redesigned, avoiding expensive down time to the users
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