Calculation of the Electromagnetic Field Around a Microtubule

Microtubules are important structures in the cytoskeleton which organizes the cell. A single microtubule is composed of electrically polar structures, tubulin heterodimers, which have a strong electric dipole moment. Vibrations are expected to be generated in microtubules, thus tubulin heterodimers oscillate as electric dipoles. This gives rise to an electromagnetic field which is detected around the cells. We calculate here the electromagnetic field of microtubules if they are excited at 1 GHz. This paper includes work done for the bachelor thesis of the first author.

Deformation pattern in vibrating microtubule: Structural mechanics study based on an atomistic approach

The mechanical properties of microtubules are of great importance for understanding their biological function and for applications in artificial devices. Although microtubule mechanics has been extensively studied both theoretically and experimentally, the relation to its molecular structure is understood only partially. Here, we report on the structural analysis of microtubule vibration modes calculated by an atomistic approach. Molecular dynamics was applied to refine the atomic structure of a microtubule and a C α elastic network model was analyzed for its normal modes. We mapped fluctuations and local deformations up to the level of individual aminoacid residues. The deformation is mode-shape dependent and principally different in α-tubulins and β-tubulins. Parts of the tubulin dimer sequence responding specifically to longitudinal and radial stress are identified. We show that substantial strain within a microtubule is located both in the regions of contact between adjacent dimers and in the body of tubulins. Our results provide supportive evidence for the generally accepted assumption that the mechanics of microtubules, including its anisotropy, is determined by the bonds between tubulins

Correction: Electro-acoustic behavior of the mitotic spindle: A semi-classical coarse-grained model (PLoS ONE (2014) 9:1 (e86501) DOI: 10.1371/journal.pone.0086501)

There are errors in the values reported for parameters a, b, c, and V in Table 1. Please see the correct Table 1 here. [Table Preasented]. There is an error in the equation in the third sentence in the “The arrangement of microtubules” subsection of the Models section. The equation describing the distance from the origin of the coordinate system for MTOC placement on the x-axis is incorrect. Please see the correct equation here: [Formola Presented]. There is an error in the Eq (6) in the “Calculation of the intensity of the electric field” subsection of the Models section. Please see the correct Eq (6) here: [Formola Presented]. There is an error in the Eq (7) in the “Calculation of the intensity of the electric field” subsection of the Models section. Please see the correct Eq (7) here: [Formola Presented]. The authors confirm that the code used in the modelling do not contain the errors in parameters and equations, which affect only the description of the models. The results and conclusions are therefore unaffected by these corrections to the reporting of the methodology. There are errors in the scale of the y-axis shown for the bottom panel of Fig 10. Please see the correct Fig 10 here.[Figure Presented]

Die epidemiologische Untersuchung der dentalen Morbidität mittels Ankete und ihre bewertung

U okviru međunarodnog projekta Svjetske zdravstvene organizacije »Korištenje zdravstvene službe i zdravstvene zaštite«, kao jedna od viiše metodoloških studija izvršena je i provjera vrijednosti ankete i valjanosti podataka o dentalnom morbiditetu. Autori su, nakon analize medicinsko-statističkih podataka utvrđenih po liječniku-stomatologu te izjave anketiranih osoba, dokazati da je postotak slaganja zadovoljavao i bio u skladu s postojećim standardima za takvu vrst \u27ispitivanja. S obzirom na reprezentativnost uzorka, autori zaključuju, da se dobiveni rezultati ispitivanja o stopama morbiditeta zubiju mogu proširiti sa anketiranog uzorka na cjelokupnu populaciju područja Istre i Hrvatskog primorja.An investigation of the condition of the oral cavity with regard to dental morbidity by means of epidemiologic methods apart from other advantages offers an insight into the distribution of diseases of a population living in certain areas or again of individual segments of the population.Within the scope of the international project of the World Health Organisation »International Collaborative Study of Medical Care Utilization« — in the further text WHO/ICS/MCU, one of the several methodologic studies in the project was the evaluation of the inquiry and the accuracy of the data on dental morbidity. The region of Istra and the Croatian Littoral, comprised by the project mentioned, numbered 440.000 inhabitants (46% belonging to the urban and 54% to the rural population). A representative sample was used, obtained by the geographical method of choice selection and the results of the investigation may thus be applied to the entire population living in that region. The problem of the study of validity was to establish to what extent we may rely on the accuracy of the data compiled be means of questionnaire forms given to subjects to complete. The actual sta\u27te of the teeth was taken as a criterium for the determination of the validity and this was established by means of a stomatological examination after the inquiry had been completed. After analysing the medical and statistical data compiled by a specialist in stomatology and the statements made by the subjects taking part in the inquirv, the percentage of agreement proved to be satisfactory. Thus the percentage of agreement in the replies given by the test subjects to questions about the number of extracted teeth as established by the inquiry and the actual number of teeth missing, as established by the examination amounted to 86,3%, dissent was recorded in 12,6% whereas no data were available for 1.2%. In the replies given by test subjects about the existence of dental-prosthetic replacements and the actual presence of dental prostheses, the percentage of agreement was 84.6% and there was dissent in 12.1% while no data were available for 2.6%. Accordingly we may rightly conclude that the data which we obtained from the questionnaires, respectively the WHO/ICS/MCU study are in accordance with the existing standards and that they represent a relatively precise indicator of the actual dental morbidity of the population investigated. With regard to the representativeness of the sample, the conclusions about the rates of morbidity of the teeth in the investigated sample may be enlarged to include the entire population of the region of Istra and the Croat Littoral.Die Prüfung des Gesundheitszustandes der Mundhöhle inbezug auf die dentale Morbidität mittels epidemiologischer Methoden, ergibt Einsicht in die Verteilung der Erkrankung bei der Menschengrupe eines bestimmten Gebietes, oder gewisser Segmente der Bevölkerung. Im Rahmen des internationalen Projekts der Weltgesundheitsorganisation »Die Auswertung des Gesundheitsdienstes und des Gesundheitschutzes« (World Health Organization; International Collaborative Study of Medical Care Utilization; — WHO/ICS/MCU), eine von mehreren Studien aus dem Projekt war Gegenstand der Feststellung des Anketenwertes und der Richtigkeit der Angaben über die dentale Morbidität. Das Gebiet von Istrien und des kroatischen Küstenlandes, welches mit dem genannten Projekt erfasst war, hat 440.000 Einwohner, davon sind 46% Stadt- und 54% Landbevölkerung). Das Muster war representativ und zugerichtet nach der geographischen Methode der zufälligen Auswahl, demnach kann man die Resultate der Untersuchung auf die Gesamtbevölkerung dieses Gebietes beziehen. Das Problem der Studie über die Validatät der Untersuchung liegt in der Feststellung, inwiefern man sich auf die Angaben der Ankete verlassen kann. Als Kriterium für die Feststellung der Validität werde der reale Zahnstatus der nach der Ankete bei der stomatologischen Untersuchung angetroffen wurde, bestimmt Die Analyse der medizinisch-statistischen Angaben, aufgenommen vom Zahnrazt, zeigt eine zufriedenstellende Übereinstimmung mit den Aussagen der anketierten Personen. Der Perzenstatz der übereinstimmenden Antworten der Probanden auf die Frage über die Anzahl der extrahierten Zähne nach Angaben der Ankete und der tatsächliche Zustand der fehlenden Zähne, festgestellt während der Untersuchung, beträgt 86,3%, während 12,6% nicht übereinstimmen bei 1,2% fehlenden Angaben.Inbezug auf zahnprothetische Arbeiten betrugen die übereinstimmenden Antworten der Probanden mit den tatsächlich vorhandenen Zahnprothesen 84,6%, 12,1% gingen auseinander bei 2,6% fehlenden Angaben Demnach kann man mit Recht schliessen, dass die Angaben der Ankete, bzw. Studien WHO/lCS/ /MCU mit den bestehenden Standarten übereinstimmen und dass sie einen ziemlich genauen Anzeiger der realen dentalen Morbidität der anketierten Bevölikerungsschichte darstellen

Sensorimotor control dynamics and cultural biases: learning to move in the right (or left) direction

The nativist hypothesis suggests universal features of human behaviour can be explained by biologically determined cognitive substrates. This nativist account has been challenged recently by evolutionary models showing that the cultural transmission of knowledge can produce behavioural universals. Sensorimotor invariance is a canonical example of a behavioural universal, raising the issue of whether culture can influence not only which skills people acquire but also the development of the sensorimotor system. We tested this hypothesis by exploring whether culture influences the developing sensorimotor system in children. We took kinematic measures of motor control asymmetries in adults and children from differing cultures where writing follows opposite directions. British and Kuwaiti adults (n = 69) and First Grade (5-6 year old) children (n = 140) completed novel rightward and leftward tracing tasks. The Kuwaitis were better when moving their arm leftward whilst the British showed the opposite bias. Bayesian analysis techniques showed that while children were worse than adults, they also showed asymmetries - with the asymmetry magnitude related to accuracy levels. Our findings support the idea that culture influences the sensorimotor system

Tubulin response to intense nanosecond-scale electric field in molecular dynamics simulation

Intense pulsed electric fields are known to act at the cell membrane level and are already being exploited in biomedical and biotechnological applications. However, it is not clear if electric pulses within biomedically-attainable parameters could directly influence intra-cellular components such as cytoskeletal proteins. If so, a molecular mechanism of action could be uncovered for therapeutic applications of such electric fields. To help clarify this question, we first identified that a tubulin heterodimer is a natural biological target for intense electric fields due to its exceptional electric properties and crucial roles played in cell division. Using molecular dynamics simulations, we then demonstrated that an intense - yet experimentally attainable - electric field of nanosecond duration can affect the bβ-tubulin’s C-terminus conformations and also influence local electrostatic properties at the GTPase as well as the binding sites of major tubulin drugs site. Our results suggest that intense nanosecond electric pulses could be used for physical modulation of microtubule dynamics. Since a nanosecond pulsed electric field can penetrate the tissues and cellular membranes due to its broadband spectrum, our results are also potentially significant for the development of new therapeutic protocols

Evolution of avalanche conducting states in electrorheological liquids

Charge transport in electrorheological fluids is studied experimentally under strongly nonequlibrium conditions. By injecting an electrical current into a suspension of conducting nanoparticles we are able to initiate a process of self-organization which leads, in certain cases, to formation of a stable pattern which consists of continuous conducting chains of particles. The evolution of the dissipative state in such system is a complex process. It starts as an avalanche process characterized by nucleation, growth, and thermal destruction of such dissipative elements as continuous conducting chains of particles as well as electroconvective vortices. A power-law distribution of avalanche sizes and durations, observed at this stage of the evolution, indicates that the system is in a self-organized critical state. A sharp transition into an avalanche-free state with a stable pattern of conducting chains is observed when the power dissipated in the fluid reaches its maximum. We propose a simple evolution model which obeys the maximum power condition and also shows a power-law distribution of the avalanche sizes.Comment: 15 pages, 6 figure

Review of invasive grapevine aphid, Aphis illinoisensis Shimer, and native parasitoids in the Mediterranean (Hemiptera, Aphididae; Hymenoptera, Braconidae, Aphidiinae)

A summary of the study of Aphis illinoisensis Shimer on grapes, Vitis vinifera in the Mediterranean area brings references and new findings on its distribution in Crete/Greece, Turkey, Northern Cyprus, Malta, Israel, Montenegro, Tunisia, Algeria and Libya. Parasitoids of A. illinoisensis were only occasionally found (Aphidius matricariae Hal. - Cyprus, Turkey, Greece; Aphidius colemani Viereck - Libya; Lysiphlebus testaceipes Cress. - Algeria). Of the native species, i.e. A. colemani, and others similar to the native species, L. testaceipes seem to be a promising biocontrol agent within the framework of an ecologically friendly management in the area. Given the evidence of its expansion, A. illinoisensis is expected to expand further in several directions from the recently documented invaded area to all the grape-growing areas of the Mediterranean and even those of South-Eastern and Central Europe

The Challenges of Releasing Human Data for Analysis

The NASA Johnson Space Center s (NASA JSC) Committee for the Protection of Human Subjects (CPHS) recently approved the formation of two human data repositories: the Lifetime Surveillance of Astronaut Health Repository (LSAH-R) for clinical data and the Life Sciences Data Archive Repository (LSDA-R) for research data. The establishment of these repositories forms the foundation for the release of data and information beyond the scope for which the data was originally collected. The release of clinical and research data and information is primarily managed by two NASA groups: the Evidence Base Working Group (EBWG), consisting of members of both repositories, and the LSAH Policy Board. The goal of unifying these repositories and their processes is to provide a mutually supportive approach to handling medical and research data, to enhance the use of medical and research data to reduce risk, and to promote the understanding of space physiology, countermeasures and other mitigation strategies. Over the past year, both repositories have received over 100 data and information requests from a wide variety of requesters. The disposition of these requests has highlighted the challenges faced when attempting to make data collected on a unique set of subjects available beyond the original intent for which the data were collected. As the EBWG works through each request, many considerations must be factored into account when deciding what data can be shared and how - from the Privacy Act of 1974 and the Health Insurance Portability and Accountability Act (HIPAA), to NASA s Health Information Management System (10HIMS) and Human Experimental and Research Data Records (10HERD) access requirements. Additional considerations include the presence of the data in the repositories and vetting requesters for legitimacy of their use of the data. Additionally, fair access must be ensured for intramural, as well as extramural investigators. All of this must be considered in the formulation of the charters, policies and workflows for the human data repositories at NASA