Leaf epidermal profiling as a phenotyping tool for DNA methylation mutants

Phenotypic evaluation of epigenetic mutants is mainly based on the analysis of plant growth and morphological features. However, there are cellular level changes that are not visible to the naked eye and require analysis with higher resolution techniques. In this study, we carried out a phenotypic characterisation of several Arabidopsis thaliana hypomethylation mutants by quantitative image analysis combined with flow cytometry. This phenotyping approach permitted identification of abnormalities at the cellular level in mutants with wild-type morphology at the organ level. Morphometry of adaxial leaf epidermis revealed variations in the size and number of pavement cells, and the density and distribution of stomata in the analysed second rosette leaves from the mutants studied. A direct correlation between DNA ploidy status and leaf pavement cell size in wild type and mutant leaves was observed. Recognition of hidden phenotypic variations could facilitate the identification of key genetic loci underlying the phenotypes caused by modifications of DNA methylation. Thus, this study outlines an easy and fast phenotyping strategy that can be used as a reliable tool for characterisation of epigenetic mutants at the cellular level

INFLUENCE OF UNITHIOL UPON NUCLEIFORMING OF BONE-MARROW LYMPHOCYTES OF RATS WITH SUBCHRONIC MERCURY INTOXICATION

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EFFECTS OF UNSOPORIFIC DOSES PHENOBARBITALUM UPON MITOSIS AND NUCLEIFORMING OF BONE-MARROW CELLS OF RATS WITH ACUTE MERCURY INTOXICATION

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A COMPARATIVE STUDY ON THE EFFECT OF MONO- AND DITHIOL ANTIDOTES ON CELL DIVISION AND NUCLEOLUS FORMATION IN ACUTE MERCURY BICHLORIDE INTOXICATION

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Preparation of ZnO nanowires by electrochemical deposition

AbstractThis work reports the results from the synthesis of nanostructured ZnO thin films via electrochemical deposition on glass substrates coated with F doped SnO2. The influence of the deposition parameters on the properties of the obtained ZnO films was studied. The Raman spectra of the ZnO films contain the typical for ZnO vibrational bands. The scanning electron microscope micrographs demonstrate that the films consist of ZnO nanowires. Growing of ZnO in the conditions with addition of H2O2 in lower concentration and without flowing air results in larger grain formation. The ZnO layers demonstrate high diffuse reflection

Fragmentation and Erosion of Two-Dimensional Aggregates in Shear Flow

We consider single two-dimensional aggregates containing glass particles trapped at a water/oil or water/air interface. Two modes for aggregate break up are observed: break up by fragmentation into a few parts and break up by erosion of single particles. We have studied the critical shear rate for these modes as a function of the aggregate size. Two different particle sizes were used. The smaller particles, with a radius of 65 m, form aggregates that break up predominantly by erosion at a shear rate between 0.5 and 0.7 s-1. This value hardly depends on the size of the aggregates. The larger particles, with a radius of 115 m, form aggregates that break by erosion or by fragmentation. In both modes, the critical shear rate again depends only weakly on the size of the aggregates and ranges between 1.6 and 2.2 s-1. Also the structural changes inside the aggregate before break up were studied. The aggregate behavior at the water/air and water/oil interfaces is quite similar. The critical shear rate for break up was also modeled. The model shows in both modes a weak dependence of the critical shear rate on the aggregate size, which is consistent with the experimental observations. The kinetics of the erosion process was also modeled and compared with the experimentally obtained time dependence of the aggregate size. The differences in the large and small particle systems can be attributed to the occurrence of friction forces between the particles, which one expects to be much larger for the large particle system, due to the stronger two-particle interactio

Motivational Social Visualizations for Personalized E-Learning

A large number of educational resources is now available on the Web to support both regular classroom learning and online learning. However, the abundance of available content produces at least two problems: how to help students find the most appropriate resources, and how to engage them into using these resources and benefiting from them. Personalized and social learning have been suggested as potential methods for addressing these problems. Our work presented in this paper attempts to combine the ideas of personalized and social learning. We introduce Progressor + , an innovative Web-based interface that helps students find the most relevant resources in a large collection of self-assessment questions and programming examples. We also present the results of a classroom study of the Progressor +  in an undergraduate class. The data revealed the motivational impact of the personalized social guidance provided by the system in the target context. The interface encouraged students to explore more educational resources and motivated them to do some work ahead of the course schedule. The increase in diversity of explored content resulted in improving students’ problem solving success. A deeper analysis of the social guidance mechanism revealed that it is based on the leading behavior of the strong students, who discovered the most relevant resources and created trails for weaker students to follow. The study results also demonstrate that students were more engaged with the system: they spent more time in working with self-assessment questions and annotated examples, attempted more questions, and achieved higher success rates in answering them

Effects of Psychopathy on Neurocognitive Domains of Impulsivity in Abstinent Opiate and Stimulant Users

Background: Psychopathy and substance use disorders (SUDs) are both characterized by neurocognitive impairments reflecting higher levels of impulsivity such as reward-driven decision-making and deficient inhibitory control. Previous studies suggest that psychopathy may exacerbate decision-making deficits, but it may be unrelated to other neurocognitive impairments among substance dependent individuals (SDIs). The aim of the present study was to examine the role of psychopathy and its interpersonal-affective and impulsive-antisocial dimensions in moderating the relationships between dependence on different classes of drugs and neurocognitive domains of impulsivity.Method: We tested 693 participants (112 heroin mono-dependent individuals, 71 heroin polysubstance dependent individuals, 115 amphetamine mono-dependent individuals, 76 amphetamine polysubstance dependent individuals, and 319 non-substance dependent control individuals). Participants were administered the Psychopathy Checklist: Screening Version (PCL:SV) and seven neurocognitive tasks measuring impulsive choice/decision-making (Iowa Gambling Task; Cambridge Gambling Task; Kirby Delay Discounting Task; Balloon Analog Risk Task), and impulsive action/response inhibition (Go/No-Go Task, Immediate Memory Task, and Stop Signal Task).Results: A series of hierarchical multiple regressions revealed that the interpersonal-affective dimension of psychopathy moderated the association between decision-making, response inhibition and both amphetamine and heroin dependence, albeit differently. For amphetamine users, low levels of interpersonal-affective traits predicted poor decision-making on the Iowa Gambling Task and better response inhibition on the Stop Signal task. In contrast, in heroin users high interpersonal-affective psychopathy traits predicted lower risk taking on the Cambridge Gambling Task and better response inhibition on the Go/No-Go task. The impulsive-antisocial dimension of psychopathy predicted poor response inhibition in both amphetamine and heroin users.Conclusions: Our findings reveal that psychopathy and its dimensions had both common and unique effects on neurocognitive function in heroin and amphetamine dependent individuals. Our results suggest that the specific interactions between psychopathy dimensions and dependence on different classes of drugs may lead to either deficient or superior decision-making and response inhibition performance in SDIs, suggesting that psychopathy may paradoxically play a protective role for some neurocognitive functions in specific subtypes of substance users