On the Properties of a Bundle of Flexible Actin Filaments in an Optical Trap

We establish the Statistical Mechanics framework for a bundle of Nf living and uncrosslinked actin filaments in a supercritical solution of free monomers pressing against a mobile wall. The filaments are anchored normally to a fixed planar surface at one of their ends and, because of their limited flexibility, they grow almost parallel to each other. Their growing ends hit a moving obstacle, depicted as a second planar wall, parallel to the previous one and subjected to a harmonic compressive force. The force constant is denoted as trap strength while the distance between the two walls as trap length to make contact with the experimental optical trap apparatus. For an ideal solution of reactive filaments and free monomers at fixed free monomers chemical potential, we obtain the general expression for the grand potential from which we derive averages and distributions of relevant physical quantities, namely the obstacle position, the bundle polymerization force and the number of filaments in direct contact with the wall. The grafted living filaments are modeled as discrete Wormlike chains, with Factin persistence length, subject to discrete contour length variations to model single monomer (de)polymerization steps. Rigid filaments, either isolated or in bundles, all provide average values of the stalling force in agreement with Hill's predictions, independent of the average trap length. Flexible filaments instead, for values of the trap strength suitable to prevent their lateral escape, provide an average bundle force and an average trap length slightly larger than the corresponding rigid cases (few percents). Still the stalling force remains nearly independent on the average trap length, but results from the product of two strongly L dependent contributions: the fraction of touching filaments and the single filament buckling force.Comment: 21 pages, 8 figure

Наноалмазы как идеальные наноносители для циансодежащих цитостатиков

Цианосодержащие цитостатики - новый класс открытых нами лекарств, которые благодаря цианогруппам хорошо закрепляются на наноалмазах, с увеличением активности

Factor structure and psychometric properties of the Italian version of the Homosexuality scale of the Trueblood Sexual Attitudes Questionnaire

The aim of the present study was to translate the Homosexuality scale of the Trueblood Sexual Attitudes Questionnaire into the Italian language and to assess its factor structure and psychometric properties in Italian psychology students. The questionnaire was originally developed and validated in U.S. college students, and later in Turkish social work students, showing high internal consistency. It measures attitudes toward several sexual practices and behaviors, regarding self and others. Particularly, the Homosexuality scale measures attitudes toward different sexual and romantic practices with people of the same sex. A total of 199 Italian psychology students participated to the study, and they were administered the Italian translation of the scale. We applied exploratory factor analysis and confirmatory factor analysis. Results showed that the scale has high internal consistency, and that the original two-factor model accounting for attitudes toward self and others fits the data well. Implications for education and assessment in student populations are discussed

Transition metal oxides using quantum Monte Carlo

The transition metal-oxygen bond appears prominently throughout chemistry and solid-state physics. Many materials, from biomolecules to ferroelectrics to the components of supernova remnants contain this bond in some form. Many of these materials' properties strongly depend on fine details of the TM-O bond and intricate correlation effects, which make accurate calculations of their properties very challenging. We present quantum Monte Carlo, an explicitly correlated class of methods, to improve the accuracy of electronic structure calculations over more traditional methods like density functional theory. We find that unlike s-p type bonding, the amount of hybridization of the d-p bond in TM-O materials is strongly dependant on electronic correlation.Comment: 20 pages, 4 figures, to appear as a topical review in J. Physics: Condensed Matte

A Single Wearable Sensor for Gait Analysis in Parkinson’s Disease: A Preliminary Study

Movement monitoring in patients with Parkinson’s disease (PD) is critical for quantifying disease progression and assessing how a subject responds to medication administration over time. In this work, we propose a continuous monitoring system based on a single wearable sensor placed on the lower back and an algorithm for gait parameters evaluation. In order to preliminarily validate the proposed system, seven PD subjects took part in an experimental protocol in preparation for a larger randomized controlled study. We validated the feasibility of our algorithm in a constrained environment through a laboratory scenario. Successively, it was tested in an unsupervised environment, such as the home scenario, for a total of almost 12 h of daily living activity data. During all phases of the experimental protocol, videos were shot to document the tasks. The obtained results showed a good accuracy of the proposed algorithm. For all PD subjects in the laboratory scenario, the algorithm for step identification reached a percentage error low of 2%, 99.13% of sensitivity and 100% of specificity. In the home scenario the Bland–Altman plot showed a mean difference of −3.29 and −1 between the algorithm and the video recording for walking bout detection and steps identification, respectively

Simulations of Dense Atomic Hydrogen in the Wigner Crystal Phase

Path integral Monte Carlo simulations are applied to study dense atomic hydrogen in the regime where the protons form a Wigner crystal. The interaction of the protons with the degenerate electron gas is modeled by Thomas-Fermi screening, which leads to a Yukawa potential for the proton-proton interaction. A numerical technique for the derivation of the corresponding action of the paths is described. For a fixed density of rs=200, the melting is analyzed using the Lindemann ratio, the structure factor and free energy calculations. Anharmonic effects in the crystal vibrations are analyzed.Comment: Proceedings article of the Study of Matter at Extreme Conditions (SMEC) conference in Miami, Florida; submitted to Journal of Physics and Chemistry of Solids (2005

Machine Learning Approach for Care Improvement of Children and Youth with Type 1 Diabetes Treated with Hybrid Closed-Loop System

Type 1 diabetes is a disease affecting beta cells of the pancreas and it’s responsible for a decreased insulin secretion, leading to an increased blood glucose level. The traditional method for glucose treatment is based on finger-stick measurement of the blood glucose concentration and consequent manual insulin injection. Nowadays insulin pumps and continuous glucose monitoring systems are replacing them, being simpler and automatized. This paper focuses on analyzing and improving the knowledge about which Machine Learning algorithms can work best with glycaemic data and tries to find out the relation between insulin pump settings and glycaemic control. The dataset is composed of 90 days of recordings taken from 16 children and adolescents. Three Machine Learning approaches, two for classification, Logistic Regression (LR) and Random Forest (RL), and one for regression, Multivariate Linear Regression (MLR), have been used for the purpose. Specifically, the pump settings analysis was performed based on the Time In Range (TIR) computation and comparison consequent to pump setting changes. RF and MLR have shown the best results, while, for the settings’ analysis, the data show a discrete correlation between changes and TIRs. This study provides an interesting closer look at the data recorded by the insulin pump and a suitable starting point for a thorough and complete analysis of them

Free energy methods in Coupled Electron Ion Monte Carlo

Recent progress in simulation methodologies and in computer power allow first principle simulations of condensed systems with Born-Oppenheimer electronic energies obtained by Quantum Monte Carlo methods. Computing free energies and therefore getting a quantitative determination of phase diagrams is one step more demanding in terms of computer resources. In this paper we derive a general relation to compute the free energy of an ab-initio model with Reptation Quantum Monte Carlo (RQMC) energies from the knowledge of the free energy of the same ab-initio model in which the electronic energies are computed by the less demanding but less accurate Variational Monte Carlo (VMC) method. Moreover we devise a procedure to correct transition lines based on the use of the new relation. In order to illustrate the procedure, we consider the liquid-liquid phase transition in hydrogen, a first order transition between a lower pressure, molecular and insulating phase and a higher pressure, partially dissociated and conducting phase. We provide new results along the T = 600K isotherm across the phase transition and find good agreement between the transition pressure and specific volumes at coexistence for the model with RQMC accuracy between the prediction of our procedure and the values that can be directly inferred from the observed plateau in the pressure-volume curve along the isotherm. This work paves the way for future use of VMC in first principle simulations of high pressure hydrogen, an essential simplification when considering larger system sizes or quantum proton effects by Path Integral Monte Carlo methods.Comment: Accepted for publication in Molecular Physic

Tuber borchii fruit body: 2-dimensional profile and protein identification

The formation of the fruit body represents the final phase of the ectomycorrhizal fungus T. borchii life cycle. Very little is known concerning the molecular and biochemical processes involved in the fructification phase. 2-DE maps of unripe and ripe ascocarps revealed different protein expression levels and the comparison of the electropherograms led to the identification of specific proteins for each developmental phase. Associating micropreparative 2-DE to microchemical approaches, such as N-terminal sequencing and 2-D gel-electrophoresis mass-spectrometry, proteins playing pivotal roles in truffle physiology were identifie

Using internet predicts attitudes towards sexual behaviour in Italian psychology students

The aim of the present study was to investigate whether the use of different sources of information about sexuality predicts attitudes towards own and towards others’ sexual behaviours, as measured through the Trueblood Sexual Attitude Questionnaire (TSAQ) Self and Other scales, in 193 Italian psychology students. The self-reported sources of information considered in the study were books, newspapers, magazines, television, internet, friends, family, and sex education courses, and age, gender, sexual orientation, and religious beliefs were tested as possible confounders. Results from hierarchical regression analyses showed that students' self-reported use of the internet predict liberal attitudes towards their own sexual behaviour, including autoeroticism, commercial sex, heterosexuality, homosexuality, and variation in sex, after controlling for age, gender, sexual orientation, and religious beliefs. On the other hand, we did not find any significant relations between self-reported information sources about sexuality and students' attitudes towards others' sexual behaviour. These results highlight the need for higher education institutions, educators and practitioners in the field of human sexuality to review sexual education programmes targeting university students, taking into account the role of the internet