Metabolism of oral glucose in children born small for gestational age : evidence for an impaired whole body glucose oxidation

Résumé Les études épidémiologiques indiquent que la restriction intra-utérine confère un risque accru de développement de diabète de type 2 au cours de la vie. Certaines études ont documenté la présence d'une résistance à l'insuline chez les jeunes adultes ou les adolescents nés petits pour l'âge gestationnel. Comme la plupart des études ont impliqués des individus post-pubères et comme la puberté influence de manière marquée le métabolisme énergétique, nous avons évalué le devenir du glucose administré oralement dans un groupe incluant essentiellement des enfants pré-pubères ou en début de puberté avec restriction intra-utérine, et chez des enfants matchés pour l'âge et pour le poids. Tous les enfants ont eu une évaluation de leur composition corporelle par mesure des plis cutanés. Ils ont ensuite été étudiés dans des conditions standardisées et ont reçu 4 charges consécutives orales de glucose à raison de 180 mg/kg de poids corporel jusqu'à atteindre un état d'équilibre relatif. La dépense énergétique et l'oxydation des substrats ont été évaluées durant la quatrième heure par calorimétrie indirecte. Comparativement avec les enfants matchés pour l'âge et le poids, les enfants nés petits pour l'âge gestationnel avaient une plus petite stature. Leur dépense énergétique n'était pas significativement abaissée, mais leur oxydation du glucose était plus basse. Ces résultats indiquent que des altérations métaboliques sont présentes précocement chez les enfants nés petits pour l'âge gestationnel, et qu'elles sont possiblement reliées à des altérations de la composition corporelle. Abstract: Epidemiological studies indicate that intrauterine growth restriction confers an increased risk of developing type 2 diabetes mellitus in subsequent life. Several studies have further documented the presence of insulin resistance in young adults or adolescent children born small for gestational age. Since most studies addressed postpubertal individuals, and since puberty markedly affects energy metabolism, we evaluated the disposal of oral glucose in a group including mainly prepubertal and early pubertal children with intrauterine growth restriction and in healthy age- and weight-matched control children. All children had an evaluation of their body composition by skinfold thickness measurements. They were then studied in standardized conditions and received 4 consecutive hourly loads of 180 mg glucose/kg body weight to reach a near steady state. Energy expenditure and substrate oxidation were evaluated during the fourth hour by indirect calorimetry. Compared to both age- and weight-matched children, children born small for gestational age had lower stature. Their energy expenditure was not significantly decreased, but they had lower glucose oxidation rates. These results indicate that metabolic alterations are present early in children born small for gestational age, and are possibly related to alterations of body composition.

Metadifferentiation of iris nevi after iridectomy: a clinicopathological small case series

Abstract Purpose Iridectomy of suspicious pigmented tumors provides the presumed advantage of both a histopathological diagnosis and treatment of the lesion. We present 2 patients that developed an iris melanoma with extrascleral extension at the site of their iridectomy of a histopathologically proven nevus, 46 and 2.5 years later. Methods Retrospective, clinicopathological small case series of 2 patients. Results Two patients underwent iridectomy for a suspicious tumor, the first in 1963 and the second in 2006. Pathological diagnosis was a benign and a borderline nevus respectively. In 2009, both patients presented with a recurrent melanocytic iridociliary tumor with an extrascleral extension adjacent to the surgical scar. Pathological examination confirmed melanoma. Consequently, the two patients underwent proton beam therapy of the whole anterior segment, with limbus deposition and reposition. Conclusion Iridectomy of a histopathologically proven nevus doesn't exclude the possibility of a metadifferentiation of remaining nevus cells into melanoma, even after 46 years. Additionally, treatment in case of a recurrence is more complicated than a primary radiotherapy of the unbiopsied iris tumor, with clinical proof of growth, would have been.

Small proline-rich protein 1A is a gp130 pathway- and stress-inducible cardioprotective protein.

The interleukin-6 cytokines, acting via gp130 receptor pathways, play a pivotal role in the reduction of cardiac injury induced by mechanical stress or ischemia and in promoting subsequent adaptive remodeling of the heart. We have now identified the small proline-rich repeat proteins (SPRR) 1A and 2A as downstream targets of gp130 signaling that are strongly induced in cardiomyocytes responding to biomechanical/ischemic stress. Upregulation of SPRR1A and 2A was markedly reduced in the gp130 cardiomyocyte-restricted knockout mice. In cardiomyocytes, MEK1/2 inhibitors prevented SPRR1A upregulation by gp130 cytokines. Furthermore, binding of NF-IL6 (C/EBPbeta) and c-Jun to the SPRR1A promoter was observed after CT-1 stimulation. Histological analysis revealed that SPRR1A induction after mechanical stress of pressure overload was restricted to myocytes surrounding piecemeal necrotic lesions. A similar expression pattern was found in postinfarcted rat hearts. Both in vitro and in vivo ectopic overexpression of SPRR1A protected cardiomyocytes against ischemic injury. Thus, this study identifies SPRR1A as a novel stress-inducible downstream mediator of gp130 cytokines in cardiomyocytes and documents its cardioprotective effect against ischemic stress.

Laskentamalli PKL-koelaitteiston pienen vuodon kokeen simuloimiseksi Apros-ohjelmistolla

Työn tavoitteena oli tehdä Apros-laskentamalli PKL-koelaitteistosta ja testata kuinka hyvin Apros pystyy laskemaan PKL-koelaitteistolla suoritetun E2.2 pienen vuodon kokeen. Tavoitteena oli myös tarkastella boorittoman veden tulpan etenemistä pienen vuodon kokeen aikana. PKL-koelaitteisto vastaa saksalaista sähköteholtaan 1300 MW olevaa Philippsburg 2 painevesilaitosta. Koelaitteiston tilavuudet ja teho on skaalattu kertoimella 145. Työssä tehdyllä laskentamallilla tarkasteltiin boorittoman veden tulpan liikkumista pienen vuodon kokeen aikana. Kun malli oli valmis, laskenta suoritettiin Apros 5.05 versiolla. Boorittoman veden tulpan etenemisen laskennassa käytettiin toisen kertaluvun diskretointia, jolla booripitoisuuden muutokset säilyvät teräväreunaisina. Laskentamalli pystyi kuvaamaan koelaitteistolla suoritetussa pienen vuodon kokeessa tapahtuneet ilmiöt varsin hyvin. Eroa koetuloksiintuli pääkiertopiirien luonnonkiertojen alkamishetkistä ja primääripaineen käyttäytymisessä. Kokeen alkutilanne ei ollut stationääritila, joten alkutilanteen asettamisessa oli hankaluuksia. Varsinkin pääkiertopiirien veden pinnankorkeuksienasettamisessa oli vaikeuksia, koska veden pinnankorkeuksien erot pyrkivät tasoittumaan nopeasti kokeen aikana. Apros pystyi laskemaan PKL-koelaitteistolla suoritetun pienen vuodon kokeen hyvin. Mallilla tulisi kuitenkin laskea vielä toisentyyppisiäkin kokeita, ennen kuin voidaan varmuudella tietää mallin toimivuus. PKL-koelaitteisto vastaa pääpiirteiltään Suomeen rakennettavaa Olkiluoto 3 ydinvoimalaitosta. Tehty työ antaa lisävarmuutta, kun Olkiluoto 3 laitoksen turvallisuustarkasteluita tehdään.

Long-term effects of neonatal hypoglycemia on brain growth and psychomotor development in small-for-gestational-age preterm infants.

OBJECTIVE: To investigate the effects of neonatal hypoglycemia on physical growth and neurocognitive function.Study design: A systematic detection of hypoglycemia (<2.6 mmol/L or 47 mg/dL) was carried out in 85 small-for-gestational-age preterm neonates. Prospective serial evaluations of physical growth and psychomotor development were performed. Retrospectively, infants were grouped according to their glycemic status. RESULTS: The incidence of hypoglycemia was 72.9%. Infants with repeated episodes of hypoglycemia had significantly reduced head circumferences and lower scores in specific psychometric tests at 3.5 years of age. Hypoglycemia also caused reduced head circumferences at 18 months and lower psychometric scores at 5 years of age. Infants with moderate recurrent hypoglycemia had lower scores at 3.5 and 5 years of age compared with the group of infants who had 1 single severe hypoglycemic episode. CONCLUSION: Recurrent episodes of hypoglycemia were strongly correlated with persistent neurodevelopmental and physical growth deficits until 5 years of age. Recurrent hypoglycemia also was a more predictable factor for long-term effects than the severity of a single hypoglycemic episode. Therefore repetitive blood glucose monitoring and rapid treatment even for mild hypoglycemia are recommended for small-for-gestational-age infants in the neonatal period.

Modules d'endo-permutation

Dans la th´eorie des repr´esentations modulaires des groupes finis, les modules d?endo-permutation occupent une place importante. En e_et, c?est le r?ole jou´e par ces modules dans l?analyse de la structure de certains modules simples pour des groupes finis p-nilpotents, qui a amen´e E. Dade `a en introduire le concept, en 1978. Quelques ann´ees plus tard, L. Puig a d´emontr´e que la source de n?importe quel module simple pour un groupe fini p-r´esoluble quelconque est un module d?endo-permutation. Plus r´ecemment, on s?est rendu compte que ces modules interviennent aussi dans l?analyse locale des cat´egories d´eriv´ees et dans l?´etude des syst`emes de fusion. La situation que l?on consid`ere est la suivante. On se donne un nombre premier p, un p-groupe fini P, un corps alg´ebriquement clos k de caract´eristique p et on veut d´eterminer tous les kP-modules d?endo-permutation couverts ind´ecomposables de type fini, c?est-`a-dire tous les kP-modules ind´ecomposables de type fini, tels que leur alg`ebre d?endomorphismes est un kP-module de permutation ayant un facteur direct trivial. On d´efinit une relation d?´equivalence sur l?ensemble de ces kP-modules et le produit tensoriel des modules induit une structure de groupe ab´elien sur l?ensemble des classes d?´equivalence. On appelle ce groupe, le groupe de Dade de P. Ainsi, classifier les modules d?endo-permutation couverts revient `a d´eterminer le groupe de Dade de P. Le groupe de Dade d?un p-groupe fini arbitraire est encore inconnu, bien qu?E. Dade, en 1978, ´etait d´ej`a parvenu `a la classification dans le cas o`u P est ab´elien. La premi`ere partie de ce travail de th`ese est consacr´ee au probl`eme de la classification dans le cas g´en´eral et r´esoud la question dans le cas de deux familles de p-groupes finis, `a savoir celle des p-groupes m´etacycliques, pour un nombre premier p impair, et celle des 2-groupes extrasp´eciaux, de la forme D8 _ · · · _ D8. Ces deux choix ont ´et´e motiv´es par le fait que ces groupes sont "presque" ab´eliens. De plus, certains r´esultats sur la structure du groupe de Dade d?un p-groupe fini quelconque rendent le groupe de Dade des groupes de ces deux familles plus simple `a ´etudier. Dans un deuxi`eme temps, nous nous sommes int´eress´es `a deux occurrences de ces modules dans la th´eorie de la repr´esentation des groupes finis, c?est-`a-dire `a deux raisons qui motivent leur ´etude. Ainsi, nous avons r´ealis´e des modules d?endo-permutation comme sources de modules simples. En particulier, il s?av`ere que, dans le cas d?un nombre premier p impair, tout module d?endo-permutation ind´ecomposable dont la classe est un ´el´ement de torsion dans le groupe de Dade est la source d?un module simple. Finalement, nous avons d´etermin´e, parmi tous les modules d?endo-permutation connus actuellement, lesquels poss`edent une r´esolution de permutation endo-scind´ee. Nous sommes arriv´es `a la conclusion que les seuls modules d?endo-permutation qui n?ont pas de r´esolution de permutation endo-scind´ee sont les modules "exceptionnels" apparaissant pour un 2-groupe de quaternions g´en´eralis´es.<br/><br/>In modular representation theory, endo-permutation modules occupy an important position. Indeed, the role that these modules play, in the analysis of the structure of some particular simple modules for finite p-nilpotent groups, induced E. Dade, in 1978, to give them their current name. A few years later, L. Puig proved that the source of any simple module for any finite psolvable group is an endo-permutation module. More recently, the occurrence of endo-permutation modules has also been noticed in the local analysis of splendid equivalences between derived categories and in the study of fusion systems. We consider the following situation. Given a prime number p, a finite pgroup P and an algebraically closed field k of characteristic p, we are looking for all finitely generated indecomposable capped endo-permutation kP-modules. That is, all finitely generated indecomposable kP-modules such that their endomorphism algebra is a permutation kP-module having a trivial direct summand. Then, we define an equivalence relation on the set of all isomorphism classes of such modules, and it turns out that the tensor product (over k) induces a structure of abelian group on this set. We call this group the Dade group of P. Hence, classifying all indecomposable finitely generated capped endo-permutation kPmodules is equivalent to determining the Dade group of P. At present, the Dade group of an arbitrary finite p-group is still unknown. However, E. Dade computed the Dade group of all finite abelian p-groups, in 1978 already. The first part of this doctoral thesis is concerned with the problem of the classification in the general case and solve it in the case of two families of finite p-groups, namely the metacyclic p-groups, for an odd prime number p, and the extraspecial 2-groups of the shape D8 _· · ·_D8. These two choices have been motivated by the fact that these groups are not far from being abelian. Moreover, some general results concerning the Dade group of arbitrary finite p-groups suggest that the Dade group of the groups belonging to these two families is easier to study. In the second part of this thesis, we have been looking at two particular occurrences of these modules in representation theory of finite groups which motivate the interest of their classification. Thus, we realised endo-permutation modules as sources of simple modules. In particular, it turns out that, in case p is an odd prime, any indecomposable module whose class in the Dade group is a torsion element is the source of some simple module. Finally, we considered all the modules we know at present and determined which ones have an endo-split permutation resolution. We could then conclude that all but the "exceptionnal" modules occurring in the generalized quaternion case have an endo-split permutation resolution.<br/><br/>"Module d?endo-permutation" n?est pas le nom d?une maladie exotique contagieuse (du moins pas `a ma connaissance), comme vous pourriez peut-?etre l?imaginer si vous faites partie des personnes qui croient que le titre de docteur n?est destin´e qu?aux m´edecins. Dans ce cas, il se peut que le sujet dont il est question ici vous cause quelques naus´ees et r´eveille de douloureux souvenirs d?´ecole, car un module d?endo-permutation est un objet math´ematique, alg´ebrique, plus pr´ecis´ement. Ce concept a ´et´e introduit il y a un quart de si`ecle, de l?autre c?ot´e de l?Atlantique, et il s?est r´ev´el´e su_samment int´eressant pour qu?aujourd?hui il ait franchi bien des fronti`eres, celles de l?alg`ebre y compris. Mais de quoi s?agit-il ? Si vous entendez le terme "endo-permutation" probablement pour la premi`ere fois, ce n?est certainement pas le cas pour celui de "module". Cependant, sa d´efinition dans le pr´esent contexte ne co¨ýncide avec aucune de celles figurant dans les dictionnaires ordinaires. Les personnes qui ont d´ej`a entendu parler de Frobenius, Burnside, Schur, ou encore Brauer, pourront vous dire qu?un module est une repr´esentation. "De quoi ?" vous demanderezvous. "Un spectacle de marionnettes, peut-?etre ?" Bien s?ur que non ! Un module d?endo-permutation est une repr´esentation particuli`ere de certains groupes finis, o`u un groupe n?est pas un groupe de rock, comme vous pouvez vous en douter, mais d´esigne un objet math´ematique connu par tous les ´etudiants en sciences au terme de leur premi`ere ann´ee universitaire (en th´eorie, du moins). La "popularit´e" de la notion de groupe, fini ou non, est due au fait que les groupes sont fr´equemment utilis´es, aussi bien dans le domaine abstrait des math´ematiques, que dans le monde r´eel des physiciens, chimistes et autres biologistes (pour ne citer qu?eux). "Mais comment peut-on utiliser concr`etement ces objets invisibles ?" vous demanderez-vous alors. Et bien, justement, en les consid´erant par l?interm´ediaire de leurs repr´esentations, c?est-`a-dire en leur associant des matrices, de fa¸con plus ou moins naturelle. Or, comme il y a "beaucoup trop" de matrices pour un groupe donn´e, elles sont classifi´ees selon certaines de leurs propri´et´es, ce qui permet de les r´epertorier dans diverses familles (celle des modules d?endo-permutation, par exemple). Un groupe est ainsi rendu "concret", car les donn´ees matricielles sont manipulables par tous les scienti- fiques (et leurs ordinateurs), qui peuvent alors les utiliser dans leurs recherches, afin de contribuer au progr`es de la science. En toute franchise, c?est bien loin de ces soucis terre-`a-terre que ce travail de th`ese sur la classification des modules d?endo-permutation a ´et´e accompli. En fait, quitte `a choquer certaines ?ames sensibles, sa r´ealisation est surtout due au caract`ere ´epicure de son auteur, qui, avouons-le, en a ´et´e pleinement satisfait !

Linking landscape- and population ecology for large population management modelling: the case of Ibex (capra ibex) in Switzerland

La biologie de la conservation est communément associée à la protection de petites populations menacées d?extinction. Pourtant, il peut également être nécessaire de soumettre à gestion des populations surabondantes ou susceptibles d?une trop grande expansion, dans le but de prévenir les effets néfastes de la surpopulation. Du fait des différences tant quantitatives que qualitatives entre protection des petites populations et contrôle des grandes, il est nécessaire de disposer de modèles et de méthodes distinctes. L?objectif de ce travail a été de développer des modèles prédictifs de la dynamique des grandes populations, ainsi que des logiciels permettant de calculer les paramètres de ces modèles et de tester des scénarios de gestion. Le cas du Bouquetin des Alpes (Capra ibex ibex) - en forte expansion en Suisse depuis sa réintroduction au début du XXème siècle - servit d?exemple. Cette tâche fut accomplie en trois étapes : En premier lieu, un modèle de dynamique locale, spécifique au Bouquetin, fut développé : le modèle sous-jacent - structuré en classes d?âge et de sexe - est basé sur une matrice de Leslie à laquelle ont été ajoutées la densité-dépendance, la stochasticité environnementale et la chasse de régulation. Ce modèle fut implémenté dans un logiciel d?aide à la gestion - nommé SIM-Ibex - permettant la maintenance de données de recensements, l?estimation automatisée des paramètres, ainsi que l?ajustement et la simulation de stratégies de régulation. Mais la dynamique d?une population est influencée non seulement par des facteurs démographiques, mais aussi par la dispersion et la colonisation de nouveaux espaces. Il est donc nécessaire de pouvoir modéliser tant la qualité de l?habitat que les obstacles à la dispersion. Une collection de logiciels - nommée Biomapper - fut donc développée. Son module central est basé sur l?Analyse Factorielle de la Niche Ecologique (ENFA) dont le principe est de calculer des facteurs de marginalité et de spécialisation de la niche écologique à partir de prédicteurs environnementaux et de données d?observation de l?espèce. Tous les modules de Biomapper sont liés aux Systèmes d?Information Géographiques (SIG) ; ils couvrent toutes les opérations d?importation des données, préparation des prédicteurs, ENFA et calcul de la carte de qualité d?habitat, validation et traitement des résultats ; un module permet également de cartographier les barrières et les corridors de dispersion. Le domaine d?application de l?ENFA fut exploré par le biais d?une distribution d?espèce virtuelle. La comparaison à une méthode couramment utilisée pour construire des cartes de qualité d?habitat, le Modèle Linéaire Généralisé (GLM), montra qu?elle était particulièrement adaptée pour les espèces cryptiques ou en cours d?expansion. Les informations sur la démographie et le paysage furent finalement fusionnées en un modèle global. Une approche basée sur un automate cellulaire fut choisie, tant pour satisfaire aux contraintes du réalisme de la modélisation du paysage qu?à celles imposées par les grandes populations : la zone d?étude est modélisée par un pavage de cellules hexagonales, chacune caractérisée par des propriétés - une capacité de soutien et six taux d?imperméabilité quantifiant les échanges entre cellules adjacentes - et une variable, la densité de la population. Cette dernière varie en fonction de la reproduction et de la survie locale, ainsi que de la dispersion, sous l?influence de la densité-dépendance et de la stochasticité. Un logiciel - nommé HexaSpace - fut développé pour accomplir deux fonctions : 1° Calibrer l?automate sur la base de modèles de dynamique (par ex. calculés par SIM-Ibex) et d?une carte de qualité d?habitat (par ex. calculée par Biomapper). 2° Faire tourner des simulations. Il permet d?étudier l?expansion d?une espèce envahisseuse dans un paysage complexe composé de zones de qualité diverses et comportant des obstacles à la dispersion. Ce modèle fut appliqué à l?histoire de la réintroduction du Bouquetin dans les Alpes bernoises (Suisse). SIM-Ibex est actuellement utilisé par les gestionnaires de la faune et par les inspecteurs du gouvernement pour préparer et contrôler les plans de tir. Biomapper a été appliqué à plusieurs espèces (tant végétales qu?animales) à travers le Monde. De même, même si HexaSpace fut initialement conçu pour des espèces animales terrestres, il pourrait aisément être étndu à la propagation de plantes ou à la dispersion d?animaux volants. Ces logiciels étant conçus pour, à partir de données brutes, construire un modèle réaliste complexe, et du fait qu?ils sont dotés d?une interface d?utilisation intuitive, ils sont susceptibles de nombreuses applications en biologie de la conservation. En outre, ces approches peuvent également s?appliquer à des questions théoriques dans les domaines de l?écologie des populations et du paysage.<br/><br/>Conservation biology is commonly associated to small and endangered population protection. Nevertheless, large or potentially large populations may also need human management to prevent negative effects of overpopulation. As there are both qualitative and quantitative differences between small population protection and large population controlling, distinct methods and models are needed. The aim of this work was to develop theoretical models to predict large population dynamics, as well as computer tools to assess the parameters of these models and to test management scenarios. The alpine Ibex (Capra ibex ibex) - which experienced a spectacular increase since its reintroduction in Switzerland at the beginning of the 20th century - was used as paradigm species. This task was achieved in three steps: A local population dynamics model was first developed specifically for Ibex: the underlying age- and sex-structured model is based on a Leslie matrix approach with addition of density-dependence, environmental stochasticity and culling. This model was implemented into a management-support software - named SIM-Ibex - allowing census data maintenance, parameter automated assessment and culling strategies tuning and simulating. However population dynamics is driven not only by demographic factors, but also by dispersal and colonisation of new areas. Habitat suitability and obstacles modelling had therefore to be addressed. Thus, a software package - named Biomapper - was developed. Its central module is based on the Ecological Niche Factor Analysis (ENFA) whose principle is to compute niche marginality and specialisation factors from a set of environmental predictors and species presence data. All Biomapper modules are linked to Geographic Information Systems (GIS); they cover all operations of data importation, predictor preparation, ENFA and habitat suitability map computation, results validation and further processing; a module also allows mapping of dispersal barriers and corridors. ENFA application domain was then explored by means of a simulated species distribution. It was compared to a common habitat suitability assessing method, the Generalised Linear Model (GLM), and was proven better suited for spreading or cryptic species. Demography and landscape informations were finally merged into a global model. To cope with landscape realism and technical constraints of large population modelling, a cellular automaton approach was chosen: the study area is modelled by a lattice of hexagonal cells, each one characterised by a few fixed properties - a carrying capacity and six impermeability rates quantifying exchanges between adjacent cells - and one variable, population density. The later varies according to local reproduction/survival and dispersal dynamics, modified by density-dependence and stochasticity. A software - named HexaSpace - was developed, which achieves two functions: 1° Calibrating the automaton on the base of local population dynamics models (e.g., computed by SIM-Ibex) and a habitat suitability map (e.g. computed by Biomapper). 2° Running simulations. It allows studying the spreading of an invading species across a complex landscape made of variously suitable areas and dispersal barriers. This model was applied to the history of Ibex reintroduction in Bernese Alps (Switzerland). SIM-Ibex is now used by governmental wildlife managers to prepare and verify culling plans. Biomapper has been applied to several species (both plants and animals) all around the World. In the same way, whilst HexaSpace was originally designed for terrestrial animal species, it could be easily extended to model plant propagation or flying animals dispersal. As these softwares were designed to proceed from low-level data to build a complex realistic model and as they benefit from an intuitive user-interface, they may have many conservation applications. Moreover, theoretical questions in the fields of population and landscape ecology might also be addressed by these approaches.

Computational Analysis and Optimization of Real Gas Flow In Small Centrifugal Compressors

Small centrifugal compressors are more and more widely used in many industrialsystems because of their higher efficiency and better off-design performance comparing to piston and scroll compressors as while as higher work coefficient perstage than in axial compressors. Higher efficiency is always the aim of the designer of compressors. In the present work, the influence of four partsof a small centrifugal compressor that compresses heavy molecular weight real gas has been investigated in order to achieve higher efficiency. Two parts concern the impeller: tip clearance and the circumferential position of the splitter blade. The other two parts concern the diffuser: the pinch shape and vane shape. Computational fluid dynamics is applied in this study. The Reynolds averaged Navier-Stokes flow solver Finflo is used. The quasi-steady approach is utilized. Chien's k-e turbulence model is used to model the turbulence. A new practical real gas model is presented in this study. The real gas model is easily generated, accuracy controllable and fairly fast. The numerical results and measurements show good agreement. The influence of tip clearance on the performance of a small compressor is obvious. The pressure ratio and efficiency are decreased as the size of tip clearance is increased, while the total enthalpy rise keeps almost constant. The decrement of the pressure ratio and efficiency is larger at higher mass flow rates and smaller at lower mass flow rates. The flow angles at the inlet and outlet of the impeller are increased as the size of tip clearance is increased. The results of the detailed flow field show that leakingflow is the main reason for the performance drop. The secondary flow region becomes larger as the size of tip clearance is increased and the area of the main flow is compressed. The flow uniformity is then decreased. A detailed study shows that the leaking flow rate is higher near the exit of the impeller than that near the inlet of the impeller. Based on this phenomenon, a new partiallyshrouded impeller is used. The impeller is shrouded near the exit of the impeller. The results show that the flow field near the exit of the impeller is greatly changed by the partially shrouded impeller, and better performance is achievedthan with the unshrouded impeller. The loading distribution on the impeller blade and the flow fields in the impeller is changed by moving the splitter of the impeller in circumferential direction. Moving the splitter slightly to the suction side of the long blade can improve the performance of the compressor. The total enthalpy rise is reduced if only the leading edge of the splitter ismoved to the suction side of the long blade. The performance of the compressor is decreased if the blade is bended from the radius direction at the leading edge of the splitter. The total pressure rise and the enthalpy rise of thecompressor are increased if pinch is used at the diffuser inlet. Among the fivedifferent pinch shape configurations, at design and lower mass flow rates the efficiency of a straight line pinch is the highest, while at higher mass flow rate, the efficiency of a concave pinch is the highest. The sharp corner of the pinch is the main reason for the decrease of efficiency and should be avoided. The variation of the flow angles entering the diffuser in spanwise direction is decreased if pinch is applied. A three-dimensional low solidity twisted vaned diffuser is designed to match the flow angles entering the diffuser. The numerical results show that the pressure recovery in the twisted diffuser is higher than in a conventional low solidity vaned diffuser, which also leads to higher efficiency of the twisted diffuser. Investigation of the detailed flow fields shows that the separation at lower mass flow rate in the twisted diffuser is later than in the conventional low solidity vaned diffuser, which leads to a possible wider flow range of the twisted diffuser.

Introducing Basic Systematic Requirements Engineering Practices in Small Organizations with an Easy to Adopt Method

Requirements-relatedissues have been found the third most important risk factor in software projects and as the biggest reason for software project failures. This is not a surprise since; requirements engineering (RE) practices have been reported deficient inmore than 75% of all; enterprises. A problem analysis on small and low maturitysoftware organizations revealed two; central reasons for not starting process improvement efforts: lack of resources and uncertainty; about process improvementeffort paybacks.; In the constructive part of the study a basic RE method, BaRE, was developed to provide an; easy to adopt way to introduce basic systematic RE practices in small and low maturity; organizations. Based on diffusion of innovations literature, thirteen desirable characteristics; were identified for the solution and the method was implemented in five key components:; requirements document template, requirements development practices, requirements; management practices, tool support for requirements management, and training.; The empirical evaluation of the BaRE method was conducted in three industrial case studies. In; this evaluation, two companies established a completely new RE infrastructure following the; suggested practices while the third company conducted continued requirements document; template development based on the provided template and used it extensively in practice. The; real benefits of the adoption of the method were visible in the companies in four to six months; from the start of the evaluation project, and the two small companies in the project completed; their improvement efforts with an input equal to about one person month. The collected dataon; the case studies indicates that the companies implemented new practices with little adaptations; and little effort. Thus it can be concluded that the constructed BaRE method is indeed easy to; adopt and it can help introduce basic systematic RE practices in small organizations.

Essays on Innovativeness and its Evaluation in Small and Medium-sized Enterprises

Tutkimus koostuu neljästä artikkelista, jotka käsittelevät suomalaisten pienten ja keskisuurten teollisuusyritysten (PKT-yritysten) innovatiivisuutta, sen attribuutteja (ominaispiirteitä) sekä indikaattoreita. Tutkimuksessa tarkastellaan sekä kirjallisuudessa esitettyjä että PKT-johtajien ja PKT-yritystenkehityshankkeiden rahoituspäätöksiin osallistuvien yritystutkijoiden haastatteluissa esittämiä innovatiivisuuden määritelmiä. Innovatiivisuusindikaattoreista tarkastellaan PKT-yritysten kehittämishankkeille sovellettavia rahoitus- ja arviointikriteerejä sekä yritysten ulkopuolisten rahoittajien että PKT-johtajien näkökulmasta. Erityistä huomiota kohdistetaan sovellettuihin laadullisiin ja ei-numeerisiin innovatiivisuuden arviointikriteereihin. Sekä kirjallisuudessa että kymmenen yritystutkijan ja kuuden esimerkkiyrityksen johtajan haastatteluissa innovaation uutuus yhdistetään innovatiivisuuteen. Muita tärkeitä innovatiivisuuteen liitettyjä ominaisuuksia olivat markkinat, muista yrityksistä erottuminen ja yksilöiden luovuus. Ihmisläheiset ja yksilöihin liittyvät näkökulmat korostuvat yritystutkijoiden ja PKT-johtajien innovatiivisuuden määritelmissä, kun taas kirjallisuudessa annetaan enemmän painoa ympäristölle, tuotteille ja markkinoille. Yritystutkijat pitivät yritykseen ja sen johtajaan liittyviä tekijöitä tärkeinä rahoitettavien kehittämishankkeiden panosten arviointikriteereinä. Tuotteiden kaupallinen menestys oli rahoittajan kannalta tärkein tulostekijä. Tarkastelluissa esimerkkiyrityksissä kehityshankkeista päättäminen ja hankkeiden arviointi on toisaalta intuitiivista ja saattaa olla tiedostamatontakin, koska yritysten kehittämistoiminta on vähäistä. Pienyritysten johtajat korostavat arvioinnissa rahallisiamittareita, vaikka sekä numeerisia että laadullisia kriteereitä sovelletaan. Todennäköisin syy tälle on pienyritysten rajalliset taloudelliset voimavarat. Toinen mahdollinen syy rahoituksellisten tekijöiden painottamiseen on, että tämän päivän ihannejohtaja ymmärretään analyyttiseksi ja mm.rahavirtoja valvovaksi. Kuitenkin innovatiiviset yritysjohtajat pitävät innovaatioiden luomista yhtenä elämän hauskoista puolista. Innovatiiviset esimerkkiyritykset ovat tulevaisuuteen ja kasvuun suuntautuneita strategisella tasolla. Operationaalisella tasolla ne tuottavat keksintöjä ja innovaatioita. Patentteja tarkastelluilla yrityksillä on kuitenkin vähän. Sekä innovatiiviset että vähemmän innovatiiviset esimerkkiyritykset ovat voimakkaasti asiakassuuntautuneita ja erikoistuneita tiettyihin tuotteisiin ja asiakkaisiin. Asiakkaiden tarpeita tyydytetään kehittämällä niitä vastaavia tuotteita. Tästä johtuu, että valtaosa yritysten kehittämistoiminnasta kohdistuu tuotteisiin tai tuotantoon.

Dynamic Model of a Small Once-Through Boiler

In this study, a model for the unsteady dynamic behaviour of a once-through counter flow boiler that uses an organic working fluid is presented. The boiler is a compact waste-heat boiler without a furnace and it has a preheater, a vaporiser and a superheater. The relative lengths of the boiler parts vary with the operating conditions since they are all parts of a single tube. The present research is a part of a study on the unsteady dynamics of an organic Rankine cycle power plant and it will be a part of a dynamic process model. The boiler model is presented using a selected example case that uses toluene as the process fluid and flue gas from natural gas combustion as the heat source. The dynamic behaviour of the boiler means transition from the steady initial state towards another steady state that corresponds to the changed process conditions. The solution method chosen was to find such a pressure of the process fluid that the mass of the process fluid in the boiler equals the mass calculated using the mass flows into and out of the boiler during a time step, using the finite difference method. A special method of fast calculation of the thermal properties has been used, because most of the calculation time is spent in calculating the fluid properties. The boiler was divided into elements. The values of the thermodynamic properties and mass flows were calculated in the nodes that connect the elements. Dynamic behaviour was limited to the process fluid and tube wall, and the heat source was regarded as to be steady. The elements that connect the preheater to thevaporiser and the vaporiser to the superheater were treated in a special way that takes into account a flexible change from one part to the other. The model consists of the calculation of the steady state initial distribution of the variables in the nodes, and the calculation of these nodal values in a dynamic state. The initial state of the boiler was received from a steady process model that isnot a part of the boiler model. The known boundary values that may vary during the dynamic calculation were the inlet temperature and mass flow rates of both the heat source and the process fluid. A brief examination of the oscillation around a steady state, the so-called Ledinegg instability, was done. This examination showed that the pressure drop in the boiler is a third degree polynomial of the mass flow rate, and the stability criterion is a second degree polynomial of the enthalpy change in the preheater. The numerical examination showed that oscillations did not exist in the example case. The dynamic boiler model was analysed for linear and step changes of the entering fluid temperatures and flow rates.The problem for verifying the correctness of the achieved results was that there was no possibility o compare them with measurements. This is why the only way was to determine whether the obtained results were intuitively reasonable and the results changed logically when the boundary conditions were changed. The numerical stability was checked in a test run in which there was no change in input values. The differences compared with the initial values were so small that the effects of numerical oscillations were negligible. The heat source side tests showed that the model gives results that are logical in the directions of the changes, and the order of magnitude of the timescale of changes is also as expected. The results of the tests on the process fluid side showed that the model gives reasonable results both on the temperature changes that cause small alterations in the process state and on mass flow rate changes causing very great alterations. The test runs showed that the dynamic model has no problems in calculating cases in which temperature of the entering heat source suddenly goes below that of the tube wall or the process fluid.

Analysis of the voltage source inverter with small DC-link capacitor

IIn electric drives, frequency converters are used to generatefor the electric motor the AC voltage with variable frequency and amplitude. When considering the annual sale of drives in values of money and units sold, the use of low-performance drives appears to be in predominant. These drives have tobe very cost effective to manufacture and use, while they are also expected to fulfill the harmonic distortion standards. One of the objectives has also been to extend the lifetime of the frequency converter. In a traditional frequency converter, a relatively large electrolytic DC-link capacitor is used. Electrolytic capacitors are large, heavy and rather expensive components. In many cases, the lifetime of the electrolytic capacitor is the main factor limiting the lifetime of the frequency converter. To overcome the problem, the electrolytic capacitor is replaced with a metallized polypropylene film capacitor (MPPF). The MPPF has improved properties when compared to the electrolytic capacitor. By replacing the electrolytic capacitor with a film capacitor the energy storage of the DC-linkwill be decreased. Thus, the instantaneous power supplied to the motor correlates with the instantaneous power taken from the network. This yields a continuousDC-link current fed by the diode rectifier bridge. As a consequence, the line current harmonics clearly decrease. Because of the decreased energy storage, the DC-link voltage fluctuates. This sets additional conditions to the controllers of the frequency converter to compensate the fluctuation from the supplied motor phase voltages. In this work three-phase and single-phase frequency converters with small DC-link capacitor are analyzed. The evaluation is obtained with simulations and laboratory measurements.

Stereotactic body radiotherapy with helical TomoTherapy for medically inoperable early stage primary and second-primary non-small-cell lung neoplasm: 1-year outcome and toxicity analysis.

OBJECTIVE: This study investigated the effectiveness of stereotactic body radiotherapy with helical TomoTherapy (T-SBRT) for treating medically inoperable primary and second-primary early stage non-small-cell lung neoplasm (SPLN) and evaluated whether the movement of organizing pneumonia (OP) within the irradiation field (IF) can be detected via analysis of radiological changes. METHODS: Patients (n = 16) treated for 1 year (2011-12) at our hospital by T-SBRT at a total dose of 60 Gy in five fractions were examined retrospectively. Outcome and toxicity were recorded and were separately described for SPLN. CT scans were reviewed by a single radiologist. RESULTS: Of the 16 patients, 5 (31.3%) had primary lung malignancies, 10 (62.5%) had SPLN, and 1 case (6.3%) had isolated mediastinal metastasis of lung neoplasm. Pathological evidence was obtained for 72.2% of all lesions. The median radiological follow-up was 11 months (10.5 months for SPLN). For all cases, the 6- and 12-month survival rates were 100% and 77.7% (100% and 71.4%, respectively, for SPLN), and the 6- and 12-month locoregional control rates were 100% in all cases. 2 (12.5%) of 16 patients developed grade 3 late transient radiation pneumonitis following steroid therapy and 1 (6.3%) presented asymptomatic infiltrates comparable to OP opacities. CONCLUSION: T-SBRT seems to be safe and effective. ADVANCES IN KNOWLEDGE: Mild OP is likely associated with radiation-induced anomalies in the IF, identification of migrating opacities can help discern relapse of radiation-induced opacities.