archivist: An R Package for Managing, Recording and Restoring Data Analysis Results

Everything that exists in R is an object [Chambers2016]. This article examines what would be possible if we kept copies of all R objects that have ever been created. Not only objects but also their properties, meta-data, relations with other objects and information about context in which they were created. We introduce archivist, an R package designed to improve the management of results of data analysis. Key functionalities of this package include: (i) management of local and remote repositories which contain R objects and their meta-data (objects' properties and relations between them); (ii) archiving R objects to repositories; (iii) sharing and retrieving objects (and it's pedigree) by their unique hooks; (iv) searching for objects with specific properties or relations to other objects; (v) verification of object's identity and context of it's creation. The presented archivist package extends, in a combination with packages such as knitr and Sweave, the reproducible research paradigm by creating new ways to retrieve and validate previously calculated objects. These new features give a variety of opportunities such as: sharing R objects within reports or articles; adding hooks to R objects in table or figure captions; interactive exploration of object repositories; caching function calls with their results; retrieving object's pedigree (information about how the object was created); automated tracking of the performance of considered models, restoring R libraries to the state in which object was archived.Comment: Submitted to JSS in 2015, conditionally accepte

Canonical and Lie-algebraic twist deformations of κ\kappa-Poincare and contractions to κ\kappa-Galilei algebras

We propose canonical and Lie-algebraic twist deformations of $\kappa$-deformed Poincare Hopf algebra which leads to the generalized $\kappa$-Minkowski space-time relations. The corresponding deformed $\kappa$-Poincare quantum groups are also calculated. Finally, we perform the nonrelativistic contraction limit to the corresponding twisted Galilean algebras and dual Galilean quantum groups.Comment: 16 pages, no figures, v3: few changes provided - version for journal, v2: submitted incidentally, v4: the page numbers for all references in preprint version are provide

Molecular basis of tRNA recognition by the Elongator complex

The highly conserved Elongator complex modifies transfer RNAs (tRNAs) in their wobble base position, thereby regulating protein synthesis and ensuring proteome stability. The precise mechanisms of tRNA recognition and its modification reaction remain elusive. Here, we show cryo–electron microscopy structures of the catalytic subcomplex of Elongator and its tRNA-bound state at resolutions of 3.3 and 4.4 Å. The structures resolve details of the catalytic site, including the substrate tRNA, the iron-sulfur cluster, and a SAM molecule, which are all validated by mutational analyses in vitro and in vivo. tRNA binding induces conformational rearrangements, which precisely position the targeted anticodon base in the active site. Our results provide the molecular basis for substrate recognition of Elongator, essential to understand its cellular function and role in neurodegenerative diseases and cancer

Polish Society of Gynecology and Obstetrics statement on safety measures and performance of ultrasound examinations in obstetrics and gynecology during the SARS-CoV-2 pandemic

We present recommendations on performance and safety measures of ultrasound examinations in obstetrics and gynecologyduring the SARS COV-2 pandemic. The statement was prepared based on the current knowledge on the coronavirusby the Ultrasound Section of the Polish Society of Obstetrics and Gynecology. It has to be noted that the presented guidanceis based on limited evidence and is primarily based on experiences published by authors from areas most affected bythe virus thus far, such as China, Singapore, Hong Kong, and Italy. We realize that the pandemic situation is very dynamic.New data is published every day. Despite the imposed limitations related to the necessity of social distancing, it is crucialto remember that providing optimal care in safe conditions should remain the primary goal of healthcare providers. Weplan to update the current guidelines as the situation develops

Cryo-EM structure of the fully assembled elongator complex

Transfer RNA (tRNA) molecules are essential to decode messenger RNA codons during protein synthesis. All known tRNAs are heavily modified at multiple positions through post-transcriptional addition of chemical groups. Modifications in the tRNA anticodons are directly influencing ribosome decoding and dynamics during translation elongation and are crucial for maintaining proteome integrity. In eukaryotes, wobble uridines are modified by Elongator, a large and highly conserved macromolecular complex. Elongator consists of two subcomplexes, namely Elp123 containing the enzymatically active Elp3 subunit and the associated Elp456 hetero-hexamer. The structure of the fully assembled complex and the function of the Elp456 subcomplex have remained elusive. Here, we show the cryo-electron microscopy structure of yeast Elongator at an overall resolution of 4.3 Å. We validate the obtained structure by complementary mutational analyses in vitro and in vivo. In addition, we determined various structures of the murine Elongator complex, including the fully assembled mouse Elongator complex at 5.9 Å resolution. Our results confirm the structural conservation of Elongator and its intermediates among eukaryotes. Furthermore, we complement our analyses with the biochemical characterization of the assembled human Elongator. Our results provide the molecular basis for the assembly of Elongator and its tRNA modification activity in eukaryotes

Preparation and property-performance relationships in samarium-doped ceria nanopowders for solid oxide fuel cell electrolytes

In a systematic study, Samarium doped ceria (SDC) nanopowders, SmxCe1-xO2-x/2 (x = 0.1, 0.2 or 0.3), were prepared by a low temperature citrate complexation route. The synthesis and crystallisation of the SDC powders were followed by thermochemical techniques (TGA/DTA). X-ray diffraction, elemental analysis, specific surface area determination (BET) and electron microscopy (SEM and TEM). Mean crystallite sizes were found to be around 10 nm for all compositions calcined at 500 degrees C. Dense electrolyte bodies were prepared at 1300 degrees C, 1400 degrees C and 1450 degrees C using two sintering times, 4 h or 6 h. Densities of 91-97% of theoretical were obtained, with a marked improvement in density on going from 1300 degrees C to higher sintering temperatures. Grain size analysis was conducted using SEM. Grain size distributions were related to %Sm and sintering conditions. Impedance spectroscopy was used to determine the total, bulk and grain boundary conductivities, the related activation energies and enthalpies of defect association and ion migration. Sintering at 1400 degrees C/6 h or 1450 degrees C/4 h gave superior grain structure and conductivity, with oversintering occurring after more severe treatments. At 600 degrees C the highest total ionic conductivity was 1.81 x 10(-2) S cm(-1) for Sm0.2Ce0.8O1.9. The relationships between chemical composition, sintering parameters, grain structure and electrochemical performance are discussed. (C) 2010 Elsevier B.V. All rights reserved.</p

Nanomaterials for solid oxide fuel cell electrolytes and reforming catalysts

In this work, a broad range of analytical methods was applied to the study of the following three materials systems: yttria-stabilised zirconia (YSZ), samarium-doped ceria (SDC) and SDC-supported metal catalysts. YSZ and SDC were studied in the light of their application as solid electrolytes in Solid Oxide Fuel Cells. The SDC-supported metal catalysts were evaluated for application in the reforming of methanol. The conductive properties of YSZ pellets derived from powders of different Y contents and particle size ranges were investigated using Impedance Spectroscopy (IS). Comparative studies of the crystallography (by X-ray Powder Diffraction (XRD)), morphology (by Scanning and Transmission Electron Microscopy (SEM, TEM)), chemical composition (by Energy Dispersive X-ray Spectroscopy (EDX) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS)) and sintering behaviour (dilatometry) were employed in the overall assessment of the conductivity results collected. Detailed studies of three SDC compositions were performed on nanopowders prepared by a low temperature method developed in the Baker group. Modifications led to a simple and reliable method for producing high quality materials with crystallites of ~10 nm diameter. The products were confirmed by XRD and TEM to be single-phase materials. Thermogravimetric analysis, dilatometry, specific surface area determination, elemental analysis and IS were carried out on these SDC powders. The relationships between particle size, chemical composition, sintering conditions and conductivity were studied in detail allowing optimum sintering conditions to be identified and ionic migration and defect association enthalpies to be calculated. Finally, the interesting results obtained for the SDC nanopowders were a driving force for the preparation of SDC-supported metal catalysts. These were prepared by three different methods and characterised in terms of crystallographic phase, specific surface area and bulk and surface chemical composition. Isothermal catalytic tests showed that all catalysts had some activity for the reforming of methanol and that some compositions showed both very high conversions and high selectivities to hydrogen. These catalysts are of interest for further study and possibly for commercial application.EThOS - Electronic Theses Online ServiceSchool of ChemistryMELEPSRCGBUnited Kingdo

Parity does not affect diabetes complications in women with type 1 diabetes

Introduction The problem concerning the impact of pregnancy on diabetic complications is a matter for discussion as there is some evidence suggesting that pregnancy may trigger development or progression of diabetic chronic complications. However, currently available data concerning this issue is still controversial. Objective The aim of the study was to evaluate the impact of obstetric history on the development of chronic microangiopatic and macroangiopatic complications in type 1 diabetic women. Material and Methods The retrospective study comprised 226 white Caucasian type 1 diabetic women, including 190 parous and 36 nulliparous women. Anthropometric data, information concerning the course of the disease, including metabolic control and chronic complications, together with obstetric history, were registered. Results Parous women were older (p 0.05) and diabetes duration (p>0.05) from nulliparous subjects. There were no significant differences in the incidence (p>0.05) nor onset (p>0.05) of chronic diabetes complications between the groups. The number of deliveries did not correlate with either the incidence nor the onset of chronic complications. Longer DM duration at the moment of first delivery was related to the higher incidence of retinopathy (p<0.01), nephropathy (p<0.05) and neuropathy (p<0.001). Conclusions The incidence of chronic diabetic complications does not differ between parous women and the subjects that were never pregnant, and is not related to the number of pregnancies