Fractoluminescence characterization of the energy dissipated during fast fracture of glass

Fractoluminescence experiments are performed on two kinds of silicate glasses. All the light spectra collected during dynamic fracture reveal a black body radiator behaviour, which is interpreted as a crack velocity-dependent temperature rise close to the crack tip. Crack velocities are estimated to be of the order of 1300 m.s$^{-1}$ and fracture process zones are shown to extend over a few nanometers.Comment: Accepted for publication in Europhysics Letters; 5 pages; 4 figure

The New (Old) Genetics, Version 1.0

The field of Genetics started flourishing after the rediscovery of the Mendelian laws of inheritance at the beginning of the 20th century. These laws are based on a discrete classification of phenotypes and their causative genes. Such a Mendelian way of thinking forms the foundation of modern molecular biology, with its experimental paradigm that a gene function is inferred from the knock-out of the gene. However, most phenotypes are not discrete. Human height, for example, is a continuous phenotype and height measures approximate a Gaussian distribution. The statistical foundation for the genetics of human height was worked out by GALTON at the end of the 19th century. He established the basis of quantitative genetics, a field that has driven the agricultural and breeding programs in the past century. It is not until very recently that the technical developments behind the human genome project have paved the way to reconcile the two contrasting ways of genetic thinking – Mendelian genetics and statistical genetics – through genome-wide analyses. It has now become clear that most phenotypes are rarely determined by single Mendelian genes, but instead, many genes contribute to their determination and variation. It has even been suggested in the omnigenic model that all genes that are expressed at the appropriate time contribute to any given phenotype. These insights are stimulating a major rethinking of how the linear genetic information laid down in the deoxyribonucleic acid (DNA) is converted into the threedimensional structure of an individual. The new conceptual and experimental paradigms have already revolutionized animal and plant breeding. In the field of human genetics, the realization that common diseases also have a polygenic basis is raising new challenges for treatment. And finally, in basic sciences like molecular and evolutionary biology, researchers are starting to revisit traditional, but oversimplified concepts on how genes act and how evolutionary adaptation works

ENOBIO - First tests of a dry electrophysiology electrode using carbon nanotubes

We describe the development and first tests of Enobio, a dry electrode sensor concept for biopotential applications. In the proposed electrodes, the tip of the electrode is covered with a forest of multi-walled CNTs that can be coated with Ag/AgCl to provide ionic-electronic transduction. The CNT brush-like structure is to penetrate the outer layers of the skin improving electrical contact as well as increae the contact surface area. In this paper, we report the results of the first tests of this concept -- immersion on saline solution and pig skin signal detection. These indicate performance on a par with state of the art research-oriented wet electrodes.Comment: Submitted and accepted at the 28th IEEE EMBS International Conference, New York City, August 31st-September 3rd, 2006. Figures updated with proper filtering and averagin

Composición, abundancia, biomasa y distribución espacio temporal del zooplancton en el sector de Palmira, Ciénaga grande de Santa Marta

Se estableció un registro de los componentes físicos-químicos y zooplanctónicos de la columna del agua en un ambiente estuarino del caribe colombiano. El estudio abarcó las épocas climáticas lluviosas y secas de la zona, en un tiempo comprendido entre los meses de septiembre a diciembre del 2001 y enero a marzo del 2002, en una estación del nororiente de la ciénaga grande de santa marta, sector de palmira, abarcando un ciclo diario de muestreo con una frecuencia de cuatro horas. La caracterización biológica del zooplancton, incluye un componente biomásico, expresada en términos de peso húmedo por el método del biovolumen y un componente correspondiente a la abundancia y composición a nivel de géneros. La colecta de los organismos se realizó con una bomba de succión tanto en la superficie como en el fondo de la columna del agua y filtrados a través de un ojo de malla de 40pm. Los mayores valores de abundancia y biomasa se presentaron durante la época lluviosa, así mismo se presentó una alta abundancia de copépodos en el mes de febrero. La comunidad zooplanctónica mostró tendencias a ser mayor hacia las horas de la tarde y en el fondo de la columna del agua; en este mismo sentido la diversidad registró tendencias a disminuir en los meses donde los valores de salinidad son bajos y aumentos en meses donde la salinidad osciló entre 16 y 34.8 ups, en los cuales se observó el mayor número de especies. En general la comunidad zooplanctónica presentó bajos niveles de correlación con los factores físicos y químicos. Palabras claves: ambiente estuarino, épocas climáticas, ciclo diario, biomasa húmeda, biovolume

First human trials of a dry electrophysiology sensor using a carbon nanotube array interface

Fatigue, sleepiness and disturbed sleep are important factors in health and safety in modern society and there is considerable interest in developing technologies for routine monitoring of associated physiological indicators. Electrophysiology, the measurement of the electrical activity of biological origin, is a key technique for the measurement of physiological parameters in several applications, but it has been traditionally difficult to develop sensors for measurements outside the laboratory or clinic with the required quality and robustness. In this paper we report the results from first human experiments using a new electrophysiology sensor called ENOBIO, using carbon nanotube arrays for penetration of the outer layers of the skin and improved electrical contact. These tests, which have included traditional protocols for the analysis of the electrical activity of the brain--spontaneous EEG and ERP--indicate performance on a par with state of the art research-oriented wet electrodes, suggesting that the envisioned mechanism--skin penetration--is responsible. No ill side-effects have been observed six months after the tests, and the subject did not report any pain or special sensations on application of the electrode

Successful management of peri-implantitis around short and ultrashort single-crown implants: a case series with a 3-year follow-up

Introduction and Aim. In case of peri-implantitis, resective surgery is contraindicated for short and ultrashort implants, limiting the treatment options to regenerative surgery or to implant removal. 'is retrospective case series presents the clinical and radiographic outcomes of a surgical regenerative procedure to treat peri-implantitis around short and ultrashort implants. Materials and Methods. The study is a retrospective evaluation of patients suffering from peri-implantitis and those who underwent access flap surgery, concomitant chemical and mechanical decontamination of implant surface, and bone grafting using a self-hardening mixture of bone substitutes and biphasic calcium sulfate. No membranes were applied to cover the grafting material, and primary tension-free closure was achieved. The retrospective protocol was reviewed and approved by the Ethics Committee for Clinical Sperimentation (CESC) of Verona and Rovigo, Italy (based in the University of Verona) (Prog. 1863CESC. Date of approval: 2018-07-04). Results. 15 patients (17 implants) have been diagnosed with peri-implantitis after a mean follow-up of 24 months after loading. Implant length was between 5 and 8 mm. 8 patients (10 implants) had a history of periodontitis. At baseline, the mean PD (probing pocket dept) at the deepest site was 8.12 mm, with an average mBI (modified bleeding index) of 2.35 and a mean BD (bone defect depth) of 3.04 mm. At the 3-year follow-up, the CSR was 100%, the mean mBI was 0.88 (average reduction: - 1.47), the mean PD was 3.35 mm (mean PD reduction: 4.77 mm), and the mean bone defect was reduced by 1.74 mm, with a mean bone fill of 55%. Conclusions. The results of the present case series suggest that if accurate surface decontamination is achieved, high survival rate and good clinical and radiographic results can be obtained after 3 years. However, only the histological examination could confirm the growth of new bone in direct contact with the implant surface or if the grafted material only fills the space left by the peri-implant defect

Axially asymmetric fermion scattering off electroweak phase transition bubble walls with hypermagnetic fields

We show that in the presence of large scale primordial hypermagnetic fields, it is possible to generate an axial asymmetry for a first order electroweak phase transition. This happens during the reflection and transmission of fermions off the true vacuum bubbles, due to the chiral nature of the fermion coupling with the background field in the symmetric phase. We derive and solve the Dirac equation for such fermions and compute the reflection and transmission coefficients for the case when these fermions move from the symmetric to the symmetry broken phase. We also comment on the possible implications of such axial charge segregation processes for baryon number generation.Comment: 8 pages, 2 Encapsulated Postscript figures, uses ReVTeX and epsfig.sty, expanded discussion, version to appear in Phys. Rev.