Brittle fracture down to femto-Joules - and below

We analyze large sets of energy-release data created by stress-induced brittle fracture in a pure sapphire crystal at close to zero temperature where stochastic fluctuations are minimal. The waiting-time distribution follows that observed for fracture in rock and for earthquakes. Despite strong time correlations of the events and the presence of large-event precursors, simple prediction algorithms only succeed in a very weak probabilistic sense. We also discuss prospects for further cryogenic experiments reaching close to single-bond sensitivity and able to investigate the existence of a transition-stress regime.Comment: REVTeX, new figure added, minor modifications to tex

Reference values of inspiratory spirometry for Finnish adults

Inspiratory spirometry is used in evaluation of upper airway disorders e.g. fixed or variable obstruction. There are, however, very few published data on normal values for inspiratory spirometry. The main aim of this study was to produce reference values for inspiratory spirometry for healthy Finnish adults.Inspiratory spirometry was preplanned to a sample of the Finnish spirometry reference values sample. Data was successfully retrieved from 368 healthy nonsmoking adults (132 males) between 19 and 83years of age. Reference equations were produced for forced inspiratory vital capacity (FIVC), forced inspiratory volume in one second (FIV1), FIV1/FIVC, peak inspiratory flow (PIF) and the ratios of FIV1/forced expiratory volume in one second and PIF/peak expiratory flow. The present values were compared to PIF values from previously used Finnish study of Viljanen etal. (1982) reference values and Norwegian values for FIV1, FIVC and FIV1/FIVC presented by Gulsvik etal. (2001). The predicted values from the Gulsvik etal. (2001), provided a good fit for FIVC, but smaller values for FIV1 with mean 108.3 and 109.1% of predicted values for males and females, respectively. PIF values were 87.4 and 91.2% of Viljanen etal. (1982) predicted values in males and females, respectively. Differences in measurement methods and selection of results may contribute to the observed differences. Inspiratory spirometry is technically more demanding and needs repeatability criteria to improve validity. New reference values are suggested to clinical use in Finland when assessing inspiratory spirometry. Utility of inspiratory to expiratory values indices in assessment of airway collapse need further study.Peer reviewe

PET-tutkimus syövän diagnostiikassa ja levinneisyysselvittelyssä

PET-TT- ja -MK-tutkimukset ovat vakiinnuttaneet asemansa syöpäkuvantamisen työkaluna tavanomaisten anatomisten kuvausmenetelmien rinnalla. Tästä on osoituksena kuvausmäärien tasainen kasvu Suomessa ja uusien kameroiden hankkiminen paitsi yliopistosairaaloissa, myös keskussairaaloissa. PET-kuvantaminen vaikuttaa syövän hoitoon ja hoitomuotojen valintaan. Menetelmä on herkkä, ja sillä voidaan paikantaa aiempaa pienempiä imusolmuke-etäpesäkkeitä tai etäpesäkkeitä jo ennen anatomisia muutoksia, erottaa aktiivisen kasvainkudoksen keuhkojen atelektaasista tai hoitojen aiheuttamista arvista sekä fibroosista. PET-menetelmästä on hyötyä syövän hoidossa hoidon suunnittelusta hoitovastearvioon sekä taudin uusiutumisen osoittamiseen. Oikein kohdennettuna kalliin kuvausmenetelmän käyttö on kustannustehokasta. Syövän tarkka levinneisyysselvittely auttaa potilaalle soveltuvimman hoidon valinnassa. PET-tutkimus ei tuo lisäarvoa kaikkien syöpien levinneisyyden selvittelyyn. Kliininen tutkimusnäyttö tarkentuu koko ajan PET-menetelmän käyttöaiheista, ja nykyään syöpätautien hoitosuosituksissa otetaan aiempaa tarkemmin kantaa, milloin PET-kuvantamisesta on osoitettu olevan kliinistä hyötyä

Dendroclimatic transfer functions revisited : Little Ice Age and Medieval Warm Period summer temperatures reconstructed using artificial neural networks and linear algorithms

Peer reviewe

Twisting Graphene Nanoribbons into Carbon Nanotubes

Although carbon nanotubes consist of honeycomb carbon, they have never been fabricated from graphene directly. Here, it is shown by quantum molecular-dynamics simulations and classical continuum-elasticity modeling, that graphene nanoribbons can, indeed, be transformed into carbon nanotubes by means of twisting. The chiralities of the tubes thus fabricated can be not only predicted but also externally controlled. This twisting route is an opportunity for nanofabrication, and is easily generalizable to ribbons made of other planar nanomaterials.Comment: 9 pages, 10 figure