Compressive force generation by a bundle of living biofilaments

To study the compressional forces exerted by a bundle of living stiff filaments pressing on a surface, akin to the case of an actin bundle in filopodia structures, we have performed particulate Molecular Dynamics simulations of a grafted bundle of parallel living (self-assembling) filaments, in chemical equilibrium with a solution of their constitutive monomers. Equilibrium is established as these filaments, grafted at one end to a wall of the simulation box, grow at their chemically active free end and encounter the opposite confining wall of the simulation box. Further growth of filaments requires bending and thus energy, which automatically limit the populations of longer filaments. The resulting filament sizes distribution and the force exerted by the bundle on the obstacle are analyzed for different grafting densities and different sub- or supercritical conditions, these properties being compared with the predictions of the corresponding ideal confined bundle model. In this analysis, non-ideal effects due to interactions between filaments and confinement effects are singled out. For all state points considered at the same temperature and at the same gap width between the two surfaces, the force per filament exerted on the opposite wall appears to be a function of a rescaled free monomer density $\hat{\rho}_1^{\rm eff}$. This quantity can be estimated directly from the characteristic length of the exponential filament size distribution $P$ observed in the size domain where these grafted filaments are not in direct contact with the wall. We also analyze the dynamics of the filament contour length fluctuations in terms of effective polymerization ($U$) and depolymerization ($W$) rates, where again it is possible to disentangle non-ideal and confinement effects.Comment: 24 pages, 7 figure

Le défi de la mécanisation : mécaniser la coupe sur 20 000 hectares

In this thesis we investigate some problems in set theoretical topology related to the concepts of the group of homeomorphisms and order. Many problems considered are directly or indirectly related to the concept of the group of homeomorphisms of a topological space onto itself. Order theoretic methods are used extensively. Chapter-l deals with the group of homeomorphisms. This concept has been investigated by several authors for many years from different angles. It was observed that nonhomeomorphic topological spaces can have isomorphic groups of homeomorphisms. Many problems relating the topological properties of a space and the algebraic properties of its group of homeomorphisms were investigated. The group of isomorphisms of several algebraic, geometric, order theoretic and topological structures had also been investigated. A related concept of the semigroup of continuous functions of a topological space also received attentionCochin University of Science and TechnologyDepartment of Mathematics and Statistics, Cochin University of Science and Technolog

Case report: targeted whole exome sequencing enables the first prenatal diagnosis of the lethal skeletal dysplasia Osteocraniostenosis.

BACKGROUND: Osteocraniostenosis (OCS) is a rare genetic disorder characterised by premature closure of cranial sutures, gracile bones and perinatal lethality. Previously, diagnosis has only been possible postnatally on clinical and radiological features. This study describes the first prenatal diagnosis of OCS. CASE PRESENTATION: In this case prenatal ultrasound images were suggestive of a serious but non-lethal skeletal dysplasia. Due to the uncertain prognosis the parents were offered Whole Exome Sequencing (WES), which identified a specific gene mutation in the FAMIIIa gene. This mutation had previously been detected in two cases and was lethal in both perinatally. This established the diagnosis, a clear prognosis and allowed informed parental choice regarding ongoing pregnancy management. CONCLUSIONS: This case report supports the use of targeted WES prenatally to confirm the underlying cause and prognosis of sonographically suspected abnormalities

Model and Performance Analysis of Piezoelectric Energy Harvester System for Different Harvester Beam Configurations

Electricity is one of the main energy resources will be used to operate many devices and appliance for making human life as comfortable. In many of the applications the small electronics equipments or devices are used which requires power in milli Watts, micro Watts, nano Watts. This small power requirement devices are gets power form battery which is nowadays replaced by the PEH energy technology. There are many configurations are used and modeled to improve the power performance of the PEH. This paper is focus on the improvements of the PEH through the continuous beam, segmented beam with tip mass and clamped – clamped continuous beam harvester. The performances of the harvesters are analyzed with the factor like voltage generation, power generation, strain stress imposed on the harvester like that. The major difficulty in the use of PEH harvester to obtain electrical energy from the vibrations or motion energy is that the output power is very less; efficiency is very poor during the low frequency periods. The vibration frequency is not at all same for all duration of vibration. So, the vibrations in the frequency reduce the output of PEH particularly at low frequency situations. So, finding and designing a suitable PEH to produce high output power in any field of vibration energy source available

The conjectures of Artin-Tate and Birch-Swinnerton-Dyer

We provide two proofs that the conjecture of Artin-Tate for a fibered surface is equivalent to the conjecture of Birch-Swinnerton-Dyer for the Jacobian of the generic fibre. As a byproduct, we obtain a new proof of a theorem of Geisser relating the orders of the Brauer group and the Tate-Shafarevich group.Comment: 13 pages, Takashi Suzuki has joined as author, new version has two proofs (second proof by Takashi Suzuki

Multiloop divergences in the closed bosonic string theory

The structure of the divergences in the multiloop vacuum diagrams for the closed bosonic strings in the framework of the Polyakov covariant formalism is discussed. It is found, by an explicit computation, that all the divergences in the theory may be interpreted as due to tadpole diagrams in which the dilaton goes into the vacuum

Short-course chemotherapy in neuro-tuberculosis - Brief review of clinical trials undertaken at the Tuberculosis Research Centre, Madras

Tuberculosis of the nervous system can present as tuberculous meningitis, tuberculoma of brain, Potts paraplegia, tuberculosis of spine and rarely as arachnoiditis and vasculitis. Tuberculosis is conventionally treated for 12 to 18 months to ensure adequate cure, stabilise quiescence and prevent relapses. With the introduction of rifampicin and pyrazinamide it became feasible to shorten the duration of chemotherapy to 6 to 9 months. Many controlled clinical trials conducted all over the world have confirmed the success of this approach in pulmonary tuberculosis by evolving 100% effective SCC regimens 1-5. In a few studies especially tuberculous lymphadenitis, tuberculous abdomen and pericarditis SCC has also been used and found to be as effective as conventional regimens6,7. However, only recently has SCC been tried for neurotuberculosis. This presentation briefly highlights some of the chemotherapy trials conducted at the Tuberculosis Research Centre in some areas of CNS tuberculosis8-10. What is SCC? SCC refers to chemotherapeutic regimens containing powerful bactericidal drugs like INH, Rifampicin and Pyrazinamide, by the use of which the duration of treatment of TB is reduced from the conventional 12 to 18 months to 6 to 9 months

A neuromorphic approach to auditory pattern recognition in cricket phonotaxis

Rost T, Ramachandran H, Nawrot MP, Chicca E. A neuromorphic approach to auditory pattern recognition in cricket phonotaxis. In: 2013 European Conference on Circuit Theory and Design (ECCTD). IEEE; 2013: 1-4.Developing neuromorphic computing paradigms that mimic nervous system function is an emerging field of research with high potential for technical applications. In the present study we take inspiration from the cricket auditory system and propose a biologically plausible neural network architecture that can explain how acoustic pattern recognition is achieved in the cricket central brain. Our circuit model combines two key features of neural processing dynamics: Spike Frequency Adaptation (SFA) and synaptic short term plasticity. We developed and extensively tested the model function in software simulations. Furthermore, the feasibility of an analogue VLSI implementation is demonstrated using a multi-neuron chip comprising Integrate-and-Fire (IF) neurons and adaptive synapses