DNA electrophoresis in designed channels

We present a simple description on the electrophoretic dynamics of polyelectrolytes going through designed channels with narrow constrictions of slit geometry. By analyzing rheological behaviours of the stuck chain, which is coupled to the effect of solvent flow, three critical electric fields (permeation field $E^{(per)} \sim N^{-1}$, deformation field $E^{(def)} \sim N^{-3/5}$ and injection field $E^{(inj)} \simeq N^0$, with $N$ polymerization index) are clarified. Between $E^{(per)}$ and $E^{(inj)}$, the chain migration is dictated by the driven activation process. In particular, at $E>E^{(def)}$, the stuck chain at the slit entrance is strongly deformed, which enhances the rate of the permeation. From these observations, electrophoretic mobility at a given electric field is deduced, which shows non-monotonic dependence on $N$. For long enough chains, mobility increases with $N$, in good agreement with experiments. An abrupt change in the electrophoretic flow at a threshold electric field is formally regarded as a nonequilibrium phase transition.Comment: 11 pages, 8 figure

COMPARATIVE STUDY OF ADULTHOOD: THE CASE STUDIES OF UNIVERSITY STUDENTS AND STUDENTS OF VOCATIONAL TRAINING ON THE ISLAND OF LEMNOS, GREECE

A comparative study of adulthood was conducted to explore the levels of self-esteem and the parameters of adulthood among students at the Aegean University, Department of Food Science and Nutrition (D.F.S.N.) and the students of public Institute of Vocational Training (Greek: IEK), both located on the Greek island of Lemnos. Thus, maturity, responsibility, autonomy, self-management and the sense of social responsibility were measured on a Likert scale and Rosenberg’s self-esteem scale. The research investigated whether being a student of Tertiary Education or a student of Vocational Training has an effect on the concept of adulthood or influences the level of individual self-esteem. The quantitative results brought to light that adulthood can be attained without direct relevance to the Educational Institute whereas the degree of self-esteem and self-management in women was determined to some extent by the choice of School. This conclusion has raised issues of major importance for further research. Article visualizations

Anomalous Dynamics of Translocation

We study the dynamics of the passage of a polymer through a membrane pore (translocation), focusing on the scaling properties with the number of monomers $N$. The natural coordinate for translocation is the number of monomers on one side of the hole at a given time. Commonly used models which assume Brownian dynamics for this variable predict a mean (unforced) passage time $\tau$ that scales as $N^2$, even in the presence of an entropic barrier. However, the time it takes for a free polymer to diffuse a distance of the order of its radius by Rouse dynamics scales with an exponent larger than 2, and this should provide a lower bound to the translocation time. To resolve this discrepancy, we perform numerical simulations with Rouse dynamics for both phantom (in space dimensions $d=1$ and 2), and self-avoiding (in $d=2$) chains. The results indicate that for large $N$, translocation times scale in the same manner as diffusion times, but with a larger prefactor that depends on the size of the hole. Such scaling implies anomalous dynamics for the translocation process. In particular, the fluctuations in the monomer number at the hole are predicted to be non-diffusive at short times, while the average pulling velocity of the polymer in the presence of a chemical potential difference is predicted to depend on $N$.Comment: 9 pages, 9 figures. Submitted to Physical Review

Anomalous Dynamics of Forced Translocation

We consider the passage of long polymers of length N through a hole in a membrane. If the process is slow, it is in principle possible to focus on the dynamics of the number of monomers s on one side of the membrane, assuming that the two segments are in equilibrium. The dynamics of s(t) in such a limit would be diffusive, with a mean translocation time scaling as N^2 in the absence of a force, and proportional to N when a force is applied. We demonstrate that the assumption of equilibrium must break down for sufficiently long polymers (more easily when forced), and provide lower bounds for the translocation time by comparison to unimpeded motion of the polymer. These lower bounds exceed the time scales calculated on the basis of equilibrium, and point to anomalous (sub-diffusive) character of translocation dynamics. This is explicitly verified by numerical simulations of the unforced translocation of a self-avoiding polymer. Forced translocation times are shown to strongly depend on the method by which the force is applied. In particular, pulling the polymer by the end leads to much longer times than when a chemical potential difference is applied across the membrane. The bounds in these cases grow as N^2 and N^{1+\nu}, respectively, where \nu is the exponent that relates the scaling of the radius of gyration to N. Our simulations demonstrate that the actual translocation times scale in the same manner as the bounds, although influenced by strong finite size effects which persist even for the longest polymers that we considered (N=512).Comment: 13 pages, RevTeX4, 16 eps figure

Effect of Periodontal Therapy on Crevicular Fluid Interleukin-6 and Interleukin-8 Levels in Chronic Periodontitis

Purpose. The aim of this study was to analyse the levels of interleukin-6 (IL-6) and interleukin-8 (IL-8) in gingival crevicular fluid (GCF) of patients with chronic periodontitis prior to and following surgical and/or nonsurgical periodontal therapy for a period of 32 weeks. Methods. GCF samples were obtained from 24 nondiseased and 72 diseased sites of 12 periodontal patients prior to as well as at 6, 16, and 32 weeks following non-surgical and surgical periodontal therapy. IL-6 and IL-8 levels were determined by enzyme-linked immunosorbent assay (ELISA). Results. Periodontal treatment improved all clinical parameters. Both treatment modalities resulted in similar IL-6 as well as IL-8 levels. Mean IL-6 and IL-8 concentrations were significantly higher in non-diseased compared to diseased sites and increased significantly following treatment in diseased sites. Mean total amounts of IL-6 and IL-8 (TAIL-6, TAIL-8) did not differ significantly between diseased and nondiseased sites, while following therapy TAIL-8 levels decreased significantly. Conclusions. The data suggest that periodontal therapy reduced the levels of IL-8 in GCF. However, a strong relationship between IL-6, IL-8 amounts in GCF and periodontal destruction and inflammation was not found

Different electromyographic features of the gastrocnemius and the tibialis anterior muscles when comparing three types of service among young sportsmen and sportswomen

This study examines the electromyographic activity of lower extremities and, in particular, of the tibialis anterior among young tennis players aged 12-16 years when performing three types of service, namely flat, slice and topspin. The study sample included 9 athletes. In order to record the muscle electric activity, three active surface electrodes were used with a pre-amplifier (Motion Control Co). Fluctuation analysis did not show statistically significant differences between parameters. Differences were observed in the activation sequence between the two muscles. In the flat service, the gastrocnemius is the first one activated, followed by the tibialis anterior. Maximum activation of the gastrocnemius occurs at initial lift-off, while the tibialis anterior towards the end of lift-off. In slice service, the two muscles are activated together and their maximum activation occurs when lift-off starts. In topspin service, the gastrocnemius is the first one activated, followed by the tibialis anterior. Maximum activation of the gastrocnemius occurs at initial lift-off, while the tibialis anterior towards the end of lift-off. Maximum activation of the two muscles occurred at the start of lift-off in all three service modes. In conclusion, young athletes need training to strengthen the tibialis anterior so as to improve lift-off velocity/acceleration in the service motion. Additionally, strengthening the tibialis anterior is a tool to improve foot lead. Such techniques are of the utmost importance during training so that skills as elaborate as those required for tennis service may be developed among young players

Evaluation of the postgraduate course “Medical Research Methodology” of the Aristotle University Medical School, 5 years after its launching

Introduction: Evaluation in education is used as a necessary procedure in order to readdress educational policy in curriculum, teaching, learning or examinations.Aims: The aim of this paper is to describe and critically analyse the evaluation process of the postgraduate course “Medical Research Methodology” of the Aristotle University Medical School, 5 years after its launching.Population: All students (190) who attended the postgraduate medical program of Aristotle University of Thessaloniki from 2004 to 2008.Method: Students were asked to rate diverse characteristics of the program on a five grade scale. According to the above mentioned aims, an on-line questionnaire was designed, piloted and implemented containing 41 close-ending and 2 openending questions.Results: Subjects regarding the aims and the final assessment of the course were graded with the highest scores. In contrast, the essays given, the students’ belief on skills gained, the clarity of the principles and techniques, as well as the quality of the supporting material, achieved lower scoring. The variability of the grades indicates that there is enough space for important improvements.Conclusion: The successful implementation of an evaluation system of a postgraduate program is producing important information and evidence for its continuous improvement

Creation of the Social Identity through the Dressing and the Representation of the Virtual Body in Virtual Internet Communities

An avatar is a gamer’s/participant’s virtual representation and manifestation in a 3D virtual world such as Second Life, World of Warcraft and others. Different appearances of avatars have different effects in the communication and behavior of the participants in virtual public spaces, as participants with more elaborate avatars had greater success in virtual social contacts than those who used avatars with a “simple” appearance. The process of creating an avatar is influenced by the virtual world’s social context where the participants act and react through their avatars. During the creation process the participants shape their avatars either like their actual appearance or nothing like it. The avatar’s appearance causes confirmatory social behaviors, as participants react subconsciously to the social imperatives underlying the expected behavior based on the digital image’s appearance. The appearance of the avatar affects the perception of the other participants with regards to the actual user behind the avatar, as their expectations of the social structures influence their behavior and they react to other avatars based on their digital appearance. So the reactions of others avatar constitute a behavioral response to the user of this avatar. Most users of virtual worlds create images that look like them, which lead to greater self-awareness of their body, and perceive their avatars as similar to their own reflection in the mirror. This permeates in the social interaction with an increased truthfulness in the representation of the individual characteristics of the participants, leading to effective contacts and interactions between users with more interpersonal confessions. Even digital worlds constitute a framework for experimentation in gender roles and a place for exploration of femininity and masculinity. It is really interesting that half of the female avatars used are actually male users. DOI: 10.5901/ajis.2016.v5n3s1p23

Construction of gender through fashion and dressing

During the last two centuries, the definitions of gender were bounded by increasingly blurred lines, expressing the cultural uncertainty surrounding masculinity and feminity. Besides it is known that gender is a social construction (and not only determined by biological sex). Two basics social - cultural factors that shape the gender are dressing and fashion. A chorography (especially the last two centuries) shows these different constructions of masculinity and femininity. The battle for the use of trousers by women (from Coco Channel and stars of Hollywood Greta Garbo, Marlene Dietrich and Katharine Hepburn play a significant role) confirm the different treatment of male and female. Fashion, which in essence is the fantasy of escape from the typical role of individuals, guiding and shaping the male and female roles, with the major fashion designers to play the key role in shaping it. Dress movements such as Macaroni (1760 - 1780), Baeu, (early 18th century), Dandies (early 19th century) and Mods (20th century) and various teen subcultures show differentiation trends of certain groups. Unisex style has tried to conceal gender differences showing a masquerade of equality for all (with the hippies and Ravers to have the basic role). On the contrary androgynous style seeks to unite the male and the female body, leading to a return to a primordial cosmic unity that will appease the gender confusion and anxiety. But eventually style and androgynous Unisex highlight the differences between the sexes.peer-reviewe