Viroids: survivors from the RNA world?

[EN] Because RNA can be a carrier of genetic information and a biocatalyst, there is a consensus that it emerged before DNA and proteins, which eventually assumed these roles and relegated RNA to intermediate functions. If such a scenario¿the so-calledRNAworld¿existed,wemight hope to find its relics in our presentworld. The properties of viroids that make them candidates for being survivors of the RNA world include those expected for primitive RNA replicons: (a) small size imposed by error-prone replication, (b) high G + C content to increase replication fidelity, (c) circular structure for assuring complete replication without genomic tags, (d ) structural periodicity for modular assembly into enlarged genomes, (e) lack of protein-coding ability consistent with a ribosome-free habitat, and ( f ) replication mediated in some by ribozymes, the fingerprint of the RNA world. With the advent of DNA and proteins, those protoviroids lost some abilities and became the plant parasites we now know.R.F. has received funding by grant BFU2011-28443 from Ministerio de Economia y Competititvidad (MINECO, Spain), R.S. by grants BFU2011-25271 (MINECO) and ERC-2011-StG-281191-VIRMUT (European Research Council), and S.F.E. by grant BFU2012-30805 (MINECO). P.S. has been supported by postdoctoral contracts from Generalitat Valenciana (APOSTD/2010, program VALi+d) and MINECO (program Juan de la Cierva).Flores Pedauye, R.; Gago Zachert, SP.; Serra Alfonso, P.; Sanjuan Verdeguer, R.; Elena Fito, SF. (2014). Viroids: survivors from the RNA world?. Annual Review of Microbiology. 68:395-414. https://doi.org/10.1146/annurev-micro-091313-103416S3954146

Spin State Disproportionation in Insulating Ferromagnetic LaCoO3 Epitaxial Thin Films

The origin of insulating ferromagnetism in epitaxial LaCoO3 films under tensile strain remains elusive despite extensive research efforts have been devoted. Surprisingly, the spin state of its Co ions, the main parameter of its ferromagnetism, is still to be determined. Here, we have systematically investigated the spin state in epitaxial LaCoO3 thin films to clarify the mechanism of strain induced ferromagnetism using element-specific x-ray absorption spectroscopy and dichroism. Combining with the configuration interaction cluster calculations, we unambiguously demonstrate that Co3+ in LaCoO3 films under compressive strain (on LaAlO3 substrate) are practically a low spin state, whereas Co3+ in LaCoO3 films under tensile strain (on SrTiO3 substrate) have mixed high spin and low spin states with a ratio close to 1:3. From the identification of this spin state ratio, we infer that the dark strips observed by high-resolution scanning transmission electron microscopy indicate the position of Co3+ high spin state, i.e., an observation of a spin state disproportionation in tensile-strained LaCoO3 films. This consequently explains the nature of ferromagnetism in LaCoO3 films

Refractive Status at Birth: Its Relation to Newborn Physical Parameters at Birth and Gestational Age

Refractive status at birth is related to gestational age. Preterm babies have myopia which decreases as gestational age increases and term babies are known to be hypermetropic. This study looked at the correlation of refractive status with birth weight in term and preterm babies, and with physical indicators of intra-uterine growth such as the head circumference and length of the baby at birth.All babies delivered at St. Stephens Hospital and admitted in the nursery were eligible for the study. Refraction was performed within the first week of life. 0.8% tropicamide with 0.5% phenylephrine was used to achieve cycloplegia and paralysis of accommodation. 599 newborn babies participated in the study. Data pertaining to the right eye is utilized for all the analyses except that for anisometropia where the two eyes were compared. Growth parameters were measured soon after birth. Simple linear regression analysis was performed to see the association of refractive status, (mean spherical equivalent (MSE), astigmatism and anisometropia) with each of the study variables, namely gestation, length, weight and head circumference. Subsequently, multiple linear regression was carried out to identify the independent predictors for each of the outcome parameters.Simple linear regression showed a significant relation between all 4 study variables and refractive error but in multiple regression only gestational age and weight were related to refractive error. The partial correlation of weight with MSE adjusted for gestation was 0.28 and that of gestation with MSE adjusted for weight was 0.10. Birth weight had a higher correlation to MSE than gestational age.This is the first study to look at refractive error against all these growth parameters, in preterm and term babies at birth. It would appear from this study that birth weight rather than gestation should be used as criteria for screening for refractive error, especially in developing countries where the incidence of intrauterine malnutrition is higher

Temperature effects on an InGaP (GaInP) (55)Fe X-ray photovoltaic cell.

This paper investigates the effects of temperature on an InGaP (GaInP) (55)Fe X-ray photovoltaic cell prototype for a radioisotope microbattery (also called a nuclear microbattery). An In0.5Ga0.5P p-i-n (5 μm i-layer) mesa photodiode was illuminated by a standard 206 MBq (55)Fe radioisotope X-ray source and characterised over the temperature range -20 °C to 100 °C. The electrical power output of the device reached its maximum value of 1.5 pW at a temperature of -20 °C. An open circuit voltage and a short circuit current of 0.82 V and 2.5 pA, respectively, were obtained at -20 °C. While the electrical power output and the open circuit voltage decreased with increasing temperature, an almost flat trend was found for the short circuit current. The cell conversion efficiency decreased from 2.1% at -20 °C to 0.7% at 100 °C

Rapid expression and purification of the hepatitis delta virus antigen using the methylotropic yeast Pichia pastoris

Objective: Patients with dual hepatitis B (HBV) and hepatitis D (HDV) virus infection are at an increased risk of progression to liver cirrhosis and hepatocellular carcinoma than patients with a single viral infection. Treatment of viral hepatitis due to dual HBV/HDV infection represents a challenge. Currently there is no vaccine against HDV. Recombinant production of HDV antigen (HDAg) is the first step towards a potential vaccine candidate and the development of assays for HDV detection. Results: This study demonstrates the expression of one HDAg isoform, S-HDAg, in Pichia pastoris. A recombinant vector carrying a tagged gene encoding S-HDAg under the control of the methanol-inducible promoter AOX1 was designed and integrated into P. pastoris X33. The protein, which was purified using a Ni2+ affinity column and eluted at 100-150 mM imidazole, has potential as a recombinant antigen for further study

KOSI- Key Object Detection for Sentiment Insights

This paper explores an original approach of using computer vision, data mining and an expert system to facilitate marketers and other interested parties to take automated data-driven decisions with the use of actionable insights. The system uses a state-of-the-art algorithm to retrieves all the images of a desired Instagram user profile. Then, the data is passed through a combination of different convolutional neural networks for object detection and a rule-based translation system to determine the interests of this profile user. Further, using a separately trained convolutional neural network with an original dataset developed as part of this study, personality insights are derived. The results from the conducted experiments yield a satisfactory prediction of interests and not very promising results for the personality prediction