Simulation of charge transport in pixelated CdTe

The Voxel Imaging PET (VIP) Pathfinder project intends to show the advantages of using pixelated semiconductor technology for nuclear medicine applications to achieve an improved image reconstruction without efficiency loss. It proposes designs for Positron Emission Tomography (PET), Positron Emission Mammography (PEM) and Compton gamma camera detectors with a large number of signal channels (of the order of 10 6). The design is based on the use of a pixelated CdTe Schottky detector to have optimal energy and spatial resolution. An individual read-out channel is dedicated for each detector voxel of size 1 × 1 × 2 mm 3 using an application-specific integrated circuit (ASIC) which the VIP project has designed, developed and is currently evaluating experimentally. The behaviour of the signal charge carriers in CdTe should be well understood because it has an impact on the performance of the readout channels. For this purpose the Finite Element Method (FEM) Multiphysics COMSOL software package has been used to simulate the behaviour of signal charge carriers in CdTe and extract values for the expected charge sharing depending on the impact point and bias voltage. The results on charge sharing obtained with COMSOL are combined with GAMOS, a Geant based particle tracking Monte Carlo software package, to get a full evaluation of the amount of charge sharing in pixelated CdTe for different gamma impact points

A Catastrophe Theory Based Model for Optimal Control of Chemical Reactions by means of Oriented Electric Fields

The e ect of oriented external electric  elds (OEEF) on chemical reactivity has been studied theoretically and computationally in the last decades. A central goal in this research area is to predict the orientation and the smallest amplitude electric  eld that renders a barrierles chemical process with the smallest possible strength. Recently, a model to  nd the optimal electric  eld has been proposed and described (J. M. Bo ll et. al., J. Chem. Theory Comput. 18, 935 (2022)). We here proof that this model is based on Catastrophe and Optimum Control Theories. Based on both theories a technical treatment of the model is given and applied to a two-dimensional generic example that provides insight into its nature and capability. Finally, the model is applied to determine the optimal OEEF for the trans-to-cis isomerization of a [3]cumulene derivative

Interplay between the gentlest ascent dynamics method and conjugate directions to locate transition states

An algorithm to locate transition states on a potential energy surface (PES) is proposed and described. The technique is based on the GAD method where the gradient of the PES is projected into a given direction and also perpendicular to it. In the proposed method, named GAD-CD, the projection is not only applied to the gradient but also to the Hessian matrix. Then, the resulting Hessian matrix is block diagonal. The direction is updated according to the GAD method. Furthermore, to ensure stability and to avoid a high computational cost, a trust region technique is incorporated and the Hessian matrix is updated at each iteration. The performance of the algorithm in comparison with the standard ascent dynamics is discussed for a simple two dimensional model PES. Its efficiency for describing the reaction mechanisms involving small and medium size molecular systems is demonstrated for five molecular systems of interest

Unexploited biodiversity data sources: the case of airborne pollen

With more than one billion primary biodiversity data records (PBR), the Global Biodiversity Information Facility (GBIF) is the largest and, arguably, most comprehensive and accurate resource about the biodiversity data on the planet. Yet, its gaps (taxonomical, geographical or chronological, among others) have often been brought to attention (Gaijy et al. 2013) and efforts are continuously made to ensure more uniform coverage. Especially as data obtained through this resource are increasingly being used for science, policy, and conservation (Ariño et al. 2018), drawing on every possible source of information to complement already existing data opens new opportunities for supplying the integrative knowledge required for global endeavors, such as understanding the global patterns of ecosystem and environment changes

Measurement of the J/Psi Production Cross Section in 920 GeV/c Fixed-Target Proton-Nucleus Interactions

The mid-rapidity (dsigma_(pN)/dy at y=0) and total sigma_(pN) production cross sections of J/Psi mesons are measured in proton-nucleus interactions. Data collected by the HERA-B experiment in interactions of 920 GeV/c protons with carbon, titanium and tungsten targets are used for this analysis. The J/Psi mesons are reconstructed by their decay into lepton pairs. The total production cross section obtained is sigma_(pN)(J/Psi) = 663 +- 74 +- 46 nb/nucleon. In addition, our result is compared with previous measurements

The Mexican consensus on the diagnosis, treatment, and prevention of NSAID-induced gastropathy and enteropathy

Más de 30 millones de personas consumen diariamente antiinflamatorios noesteroideos (AINE) en el mundo, y este consumo se ve incrementado anualmente. Aunque losAINE poseen propiedades analgésicas y antiinflamatorias, sus eventos adversos gastrointesti-nales son bien reconocidos. En nuestro país no existía un consenso respecto al diagnóstico,tratamiento y prevención de la gastropatía y la enteropatía por AINE, por lo que la AsociaciónMexicana de Gastroenterología reunió a un grupo de expertos para establecer recomendacionesde utilidad para la comunidad médica. En este consenso se emitieron 33 recomendaciones. Elconsenso destaca que el riesgo de toxicidad gastrointestinal de los AINE varía según el fármacoempleado y su farmacocinética, lo cual debe ser considerado al momento de su prescripción. Losfactores de riesgo de complicación gastroduodenal por AINE son: antecedente de úlcera pép-tica, edad mayor a 65 a˜nos, dosis altas del AINE, infección por Helicobacter pylori (H.pylori), ypresencia de comorbilidades graves. Los síntomas y el da˜no gastroduodenal inducido por AINEson variables ya que puede cursar asintomático o manifestarse como anemia por deficiencia dehierro, hemorragia, estenosis y perforación. La cápsula endoscópica y la enteroscopia son méto-dos diagnósticos directos en la enteropatía por AINE. Respecto a la prevención, se recomiendaprescribir la dosis mínima necesaria de un AINE para obtener el efecto deseado y durante elmenor tiempo. Finalmente, los inhibidores de la bomba de protones (IBP) representan el están-dar de oro para la profilaxis y tratamiento de los efectos gastroduodenales, mas no son útilesen la enteropatía

Investment in the long-tail of biodiversity data: from local research to global knowledge

In business, the "long-tail economy" refers to a market strategy where the gravity center shifts from a few high-demand products to many, varied products focused on small niches. Commercialization of individually low-demand products can be profitable as long as their production cost is low and, all taken together, they aggregate into a big chunk of the market. Similarly, in the "business" of biodiversity data acquisition, we can find several mainstream products that produce zillions of bits of information every year and account for most of the budget allocated to increase our primary data-based knowledge about Earth's biological diversity. These products play a crucial role in biodiversity research. However, along with these large global projects, there is a constellation of small-scale institutions that work locally, but whose contribution to our understanding of natural processes should not be dismissed. These information datasets can be collectively referred to as the "long-tail biodiversity data"

Moonlighting Proteins Hal3 and Vhs3 Form a Heteromeric PPCDC with Ykl088w in Yeast CoA Biosynthesis

Premi a l'excel·lència investigadora. 2010Unlike most other organisms, the essential five-step Coenzyme A biosynthetic pathway has not been fully resolved in yeast. Specifically, the gene(s) encoding the phosphopantothenoylcysteine decarboxylase (PPCDC) activity still remains unidentified. Sequence homology analyses suggest three candidates, namely Ykl088w, Hal3 and Vhs3, as putative PPCDC enzymes in Saccharomyces cerevisiae. Interestingly, Hal3 and Vhs3 have been characterized as negative regulatory subunits of the Ppz1 protein phosphatase. Here we show that YKL088w does not encode a third Ppz1 regulatory subunit, and that the essential roles of Ykl088w and the Hal3/Vhs3 pair are complementary, cannot be interchanged and can be attributed to PPCDC-related functions. We demonstrate that while known eukaryotic PPCDCs are homotrimers, the active yeast enzyme is a heterotrimer which consists of Ykl088w and Hal3/Vhs3 monomers that separately provides two essential catalytic residues. Our results unveil Hal3/Vhs3 as moonlighting proteins, involved in both CoA biosynthesis and protein phosphatase regulation

European registry on helicobacter pylori management: Effectiveness of first and second-line treatment in Spain

The management of Helicobacter pylori infection has to rely on previous local effectiveness due to the geographical variability of antibiotic resistance. The aim of this study was to evaluate the effectiveness of first and second-line H. pylori treatment in Spain, where the empirical prescription is recommended. A multicentre prospective non-interventional registry of the clinical practice of European gastroenterologists concerning H. pylori infection (Hp-EuReg) was developed, including patients from 2013 until June 2019. Effectiveness was evaluated descriptively and through a multivariate analysis concerning age, gender, presence of ulcer, proton-pump in-hibitor (PPI) dose, therapy duration and compliance. Overall, 53 Spanish hospitals were included, and 10, 267 patients received a first-line therapy. The best results were obtained with the 10-day bismuth single-capsule therapy (95% cure rate by intention-to-treat) and with both the 14-day bismuth-clarithromycin quadruple (PPI-bismuth-clarithromycin-amoxicillin, 91%) and the 14-day non-bismuth quadruple concomitant (PPI-clarithromycin-amoxicillin-metronidazole, 92%) therapies. Second-line therapies were prescribed to 2448 patients, with most-effective therapies being the triple quinolone (PPI-amoxicillin-levofloxacin/moxifloxacin) and the bismuth-levofloxacin quadruple schemes (PPI-bismuth-levofloxacin-amoxicillin) prescribed for 14 days (92%, 89% and 90% effective-ness, respectively), and the bismuth single-capsule (10 days, 88.5%). Compliance, longer duration and higher acid inhibition were associated with higher effectiveness. “Optimized” H. pylori therapies achieve over 90% success in Spain