Investigation of resins suitable for the preparation of biological sample for 3-D electron microscopy.

In the last two decades, the third-dimension has become a focus of attention in electron microscopy to better understand the interactions within subcellular compartments. Initially, transmission electron tomography (TEM tomography) was introduced to image the cell volume in semi-thin sections (∼500nm). With the introduction of the focused ion beam scanning electron microscope, a new tool, FIB-SEM tomography, became available to image much larger volumes. During TEM tomography and FIB-SEM tomography, the resin section is exposed to a high electron/ion dose such that the stability of the resin embedded biological sample becomes an important issue. The shrinkage of a resin section in each dimension, especially in depth, is a well-known phenomenon. To ensure the dimensional integrity of the final volume of the cell, it is important to assess the properties of the different resins and determine the formulation which has the best stability in the electron/ion beam. Here, eight different resin formulations were examined. The effects of radiation damage were evaluated after different times of TEM irradiation. To get additional information on mass-loss and the physical properties of the resins (stiffness and adhesion), the topography of the irradiated areas was analysed with atomic force microscopy (AFM). Further, the behaviour of the resins was analysed after ion milling of the surface of the sample with different ion currents. In conclusion, two resin formulations, Hard Plus and the mixture of Durcupan/Epon, emerged that were considerably less affected and reasonably stable in the electron/ion beam and thus suitable for the 3-D investigation of biological samples.

Soil Stabilization With Chemicals, Iowa Highway Research Board Bulletin No. 22, 1960

In the search for new soil stabilizing agents the effects of six organic cations on plastic limit, liquid limit, shrinkage limit, air-dry strength and rate of slaking of a highly plastic clay subsoil were studied. In all cases the plasticity index and shrinkage were reduced by the treatments. The air-dry strength was lowered in varying degree, which was the only undesirable effect noted. With one exception resistance to slaking was improved. It is concluded that large organic cations show promise as possible stabilizing agents for highly plastic fine-grained soils.

Vessel centerline tracking and boundary sgementation in coronary MRA with minimal manual interaction.

Magnetic resonance angiography (MRA) provides a noninvasive means to detect the presence, location and severity of atherosclerosis throughout the vascular system. In such studies, and especially those in the coronary arteries, the vessel luminal area is typically measured at multiple cross-sectional locations along the course of the artery. The advent of fast volumetric imaging techniques covering proximal to mid segments of coronary arteries necessitates automatic analysis tools requiring minimal manual interactions to robustly measure cross-sectional area along the three-dimensional track of the arteries in under-sampled and non-isotropic datasets. In this work, we present a modular approach based on level set methods to track the vessel centerline, segment the vessel boundaries, and measure transversal area using two user-selected endpoints in each coronary of interest. Arterial area and vessel length are measured using our method and compared to the standard Soap-Bubble reformatting and analysis tool in in-vivo non-contrast enhanced coronary MRA images.

Enterocystoplasty using modified pedicled, detubularized, de-epithelialized sigmoid patches in the mini-pig model.

Enterocystoplasty and gastrocystoplasty have been developed to restore adequate bladder capacity but they still result in the undesired harmful contact of urine with the intestinal mucosa. In an attempt to prevent this nonphysiological interface we performed several modified enterocystoplasties in the mini-pig model using a pedicled, detubularized, de-epithelialized sigmoid patch. Five techniques of patch coverage were used to evaluate urothelial growth or survival on the sigmoid patch. All but 1 patch had intestinal mucosa remnants with mucocele formation. When no coverage was applied or a biodegradable polyglactin mesh was temporarily covering the pedicled, detubularized, de-epithelialized sigmoid patch, severe shrinkage occurred. Partial cover with autologous urothelium islets seemed to decrease shrinkage. Adequate urothelium survival and satisfactory elastic properties of the patch were observed when total cover of the sigmoid patch was achieved with a sheet of homologous urothelium recovering autologous urothelial islets or when the patch was applied to protruding urothelium obtained following sagittal posterior detrusor myotomy.

Trabecular Bone Score (TBS)--A Novel Method to Evaluate Bone Microarchitectural Texture in Patients With Primary Hyperparathyroidism.

Context: In the milder form of primary hyperparathyroidism (PHPT), cancellous bone, represented by areal bone mineral density at the lumbar spine by dual-energy x-ray absorptiometry (DXA), is preserved. This finding is in contrast to high-resolution peripheral quantitative computed tomography (HRpQCT) results of abnormal trabecular microstructure and epidemiological evidence for increased overall fracture risk in PHPT. Because DXA does not directly measure trabecular bone and HRpQCT is not widely available, we used trabecular bone score (TBS), a novel gray-level textural analysis applied to spine DXA images, to estimate indirectly trabecular microarchitecture. Objective: The purpose of this study was to assess TBS from spine DXA images in relation to HRpQCT indices and bone stiffness in radius and tibia in PHPT. Design and Setting: This was a cross-sectional study conducted in a referral center. Patients: Participants were 22 postmenopausal women with PHPT. Main Outcome Measures: Outcomes measured were areal bone mineral density by DXA, TBS indices derived from DXA images, HRpQCT standard measures, and bone stiffness assessed by finite element analysis at distal radius and tibia. Results: TBS in PHPT was low at 1.24, representing abnormal trabecular microstructure (normal ≥1.35). TBS was correlated with whole bone stiffness and all HRpQCT indices, except for trabecular thickness and trabecular stiffness at the radius. At the tibia, correlations were observed between TBS and volumetric densities, cortical thickness, trabecular bone volume, and whole bone stiffness. TBS correlated with all indices of trabecular microarchitecture, except trabecular thickness, after adjustment for body weight. Conclusion: TBS, a measurement technology readily available by DXA, shows promise in the clinical assessment of trabecular microstructure in PHPT.

Computer-aided volume measurement of posttraumatic orbits reconstructed with AO titanium mesh plates: accuracy and reliability

PURPOSE: To prospectively evaluate the accuracy and reliability of "freehand" posttraumatic orbital wall reconstruction with AO (Arbeitsgemeinschaft Osteosynthese) titanium mesh plates by using computer-aided volumetric measurement of the bony orbits. METHODS: Bony orbital volume was measured in 12 patients from coronal CT scan slices using OsiriX Medical Image software. After defining the volumetric limits of the orbit, the segmentation of the bony orbital region of interest of each single slice was performed. At the end of the segmentation process, all regions of interest were grouped and the volume was computed. The same procedure was performed on both orbits, and thereafter the volume of the contralateral uninjured orbit was used as a control for comparison. RESULTS: In all patients, the volume data of the reconstructed orbit fitted that of the contralateral uninjured orbit with accuracy to within 1.85 cm3 (7%). CONCLUSIONS: This preliminary study has demonstrated that posttraumatic orbital wall reconstruction using "freehand" bending and placement of AO titanium mesh plates results in a high success rate in re-establishing preoperative bony volume, which closely approximates that of the contralateral uninjured orbit.

Functional independence within the self-memory system: new insights from two cases of developmental amnesia.

Neuropsychological and neuroimaging data suggest that the self-memory system can be fractionated into three functionally independent systems processing personal information at several levels of abstraction, including episodic memories of one's life (episodic autobiographical memory, EAM), semantic knowledge of facts about one's life (semantic autobiographical memory, SAM), and semantic knowledge of one's personality [conceptual self, (CS)]. Through the study of two developmental amnesic patients suffering of neonatal brain injuries, we explored how the different facets of the self-memory system develop when growing up with bilateral hippocampal atrophy. Neuropsychological evaluations showed that both of them suffered from dramatic episodic learning disability with no sense of recollection (Remember/Know procedure), whereas their semantic abilities differed, being completely preserved (Valentine) or not (Jocelyn). Magnetic resonance imaging, including quantitative volumetric measurements of the hippocampus and adjacent (entorhinal, perirhinal, and temporopolar) cortex, showed severe bilateral atrophy of the hippocampus in both patients, with additional atrophy of adjacent cortex in Jocelyn. Exploration of EAM and SAM according to lifetime periods covering the entire lifespan (TEMPAu task, Piolino et al., 2009) showed that both patients had marked impairments in EAM, as they lacked specificity, details and sense of recollection, whereas SAM was completely normal in Valentine, but impaired in Jocelyn. Finally, measures of patients' CS (Tennessee Self-Concept Scale, Fitts and Warren, 1996), checked by their mothers, were generally within normal range, but both patients showed a more positive self-concept than healthy controls. These two new cases support a modular account of the medial-temporal lobe with episodic memory and recollection depending on the hippocampus, and semantic memory and familiarity on adjacent cortices. Furthermore, they highlight developmental episodic and semantic functional independence within the self-memory system suggesting that SAM and CS may be acquired without episodic memories.

Stability Evaluation of a Paper Machine Wet End

Työssä analysoidaanprosessin vaikutusta paperikoneen stabiiliuteen. Kaksi modernia sanomalehtipaperikonetta analysoitiin ja sen perusteella molemmista prosesseista rakennettiin fysiikan lakeihin perustuvat simulointimallit APROS Paper simulointiohjelmistolla. Työn tavoitteena on selvittää, miten kyseisten koneiden prosessit eroavat toisistaan ja arvioida, miten havaitut erot vaikuttavat prosessien stabiiliuteen. Työssä tarkastellaan periodisten häiriöiden vaimenemista prosessissa. Simuloinnissa herätteenä käytettiin puhdasta valkoista kohinaa, jonka avulla eri taajuistenperiodisten häiriöiden vaimenemista analysoitiin. Prosessien häiriövasteet esitetään taajuuskoordinaatistossa. Suurimmat erot prosessien välillä löytyivät viirakaivosta ja sen sekoitusdynamiikasta. Perinteisen viirakaivon todettiin muistuttavan käyttäytymiseltään sarjaan kytkettyjä ideaalisekoittimia, kun taas pienempitilavuuksisen fluumin todettiin käyttäytyvän lähes kuin putkiviive. Vaikka erotprosessitilavuudessa sekä viirakaivon sekoitusdynamiikassa olivat hyvin selkeät, havaittiin vain marginaalinen ero prosessin välillä periodisten häiriöiden vaimenemisessa, koska erot viiraretentiotasoissa vaikuttivat eniten simulointituloksia. Matalammalla viiraretentiolla operoivan paperikoneen todettiin vaimentavan tehokkaammin prosessihäiriöitä. Samalla retentiotasolla pienempitilavuuksisen prosessin todettiin vaimentavan hitaita prosessihäiriöitä marginaalisesti paremmin. Tutkituista paperikoneista toisella simuloitiin viiraosan vedenpoistomuutoksenvaikutusta viiraretentioon ja paperin koostumukseen. Lisäksi arvioitiin viiraretention säädön toimivuutta. Viiraosan listakengän vedenpoiston todettiin aiheuttavan merkittäviä sakeus- ja retentiohäiriöitä, mikäli sen avulla poistettavan kiintoaineen virtaus tuplaantuisi. Viiraretention säädön todettiin estävän häiriöiden kierron prosessissa, mutta siirtävän ne suoraan rainaan. Retention säädön eikuitenkaan todettu olevan suoranainen häiriön lähde.

Développement et validation d'une méthode de calcul indépendant des unités moniteur basée sur les simulations Monte Carlo pour la vérification des traitements IMRT

Résumé : La radiothérapie par modulation d'intensité (IMRT) est une technique de traitement qui utilise des faisceaux dont la fluence de rayonnement est modulée. L'IMRT, largement utilisée dans les pays industrialisés, permet d'atteindre une meilleure homogénéité de la dose à l'intérieur du volume cible et de réduire la dose aux organes à risque. Une méthode usuelle pour réaliser pratiquement la modulation des faisceaux est de sommer de petits faisceaux (segments) qui ont la même incidence. Cette technique est appelée IMRT step-and-shoot. Dans le contexte clinique, il est nécessaire de vérifier les plans de traitement des patients avant la première irradiation. Cette question n'est toujours pas résolue de manière satisfaisante. En effet, un calcul indépendant des unités moniteur (représentatif de la pondération des chaque segment) ne peut pas être réalisé pour les traitements IMRT step-and-shoot, car les poids des segments ne sont pas connus à priori, mais calculés au moment de la planification inverse. Par ailleurs, la vérification des plans de traitement par comparaison avec des mesures prend du temps et ne restitue pas la géométrie exacte du traitement. Dans ce travail, une méthode indépendante de calcul des plans de traitement IMRT step-and-shoot est décrite. Cette méthode est basée sur le code Monte Carlo EGSnrc/BEAMnrc, dont la modélisation de la tête de l'accélérateur linéaire a été validée dans une large gamme de situations. Les segments d'un plan de traitement IMRT sont simulés individuellement dans la géométrie exacte du traitement. Ensuite, les distributions de dose sont converties en dose absorbée dans l'eau par unité moniteur. La dose totale du traitement dans chaque élément de volume du patient (voxel) peut être exprimée comme une équation matricielle linéaire des unités moniteur et de la dose par unité moniteur de chacun des faisceaux. La résolution de cette équation est effectuée par l'inversion d'une matrice à l'aide de l'algorithme dit Non-Negative Least Square fit (NNLS). L'ensemble des voxels contenus dans le volume patient ne pouvant être utilisés dans le calcul pour des raisons de limitations informatiques, plusieurs possibilités de sélection ont été testées. Le meilleur choix consiste à utiliser les voxels contenus dans le Volume Cible de Planification (PTV). La méthode proposée dans ce travail a été testée avec huit cas cliniques représentatifs des traitements habituels de radiothérapie. Les unités moniteur obtenues conduisent à des distributions de dose globale cliniquement équivalentes à celles issues du logiciel de planification des traitements. Ainsi, cette méthode indépendante de calcul des unités moniteur pour l'IMRT step-andshootest validée pour une utilisation clinique. Par analogie, il serait possible d'envisager d'appliquer une méthode similaire pour d'autres modalités de traitement comme par exemple la tomothérapie. Abstract : Intensity Modulated RadioTherapy (IMRT) is a treatment technique that uses modulated beam fluence. IMRT is now widespread in more advanced countries, due to its improvement of dose conformation around target volume, and its ability to lower doses to organs at risk in complex clinical cases. One way to carry out beam modulation is to sum smaller beams (beamlets) with the same incidence. This technique is called step-and-shoot IMRT. In a clinical context, it is necessary to verify treatment plans before the first irradiation. IMRT Plan verification is still an issue for this technique. Independent monitor unit calculation (representative of the weight of each beamlet) can indeed not be performed for IMRT step-and-shoot, because beamlet weights are not known a priori, but calculated by inverse planning. Besides, treatment plan verification by comparison with measured data is time consuming and performed in a simple geometry, usually in a cubic water phantom with all machine angles set to zero. In this work, an independent method for monitor unit calculation for step-and-shoot IMRT is described. This method is based on the Monte Carlo code EGSnrc/BEAMnrc. The Monte Carlo model of the head of the linear accelerator is validated by comparison of simulated and measured dose distributions in a large range of situations. The beamlets of an IMRT treatment plan are calculated individually by Monte Carlo, in the exact geometry of the treatment. Then, the dose distributions of the beamlets are converted in absorbed dose to water per monitor unit. The dose of the whole treatment in each volume element (voxel) can be expressed through a linear matrix equation of the monitor units and dose per monitor unit of every beamlets. This equation is solved by a Non-Negative Least Sqvare fif algorithm (NNLS). However, not every voxels inside the patient volume can be used in order to solve this equation, because of computer limitations. Several ways of voxel selection have been tested and the best choice consists in using voxels inside the Planning Target Volume (PTV). The method presented in this work was tested with eight clinical cases, which were representative of usual radiotherapy treatments. The monitor units obtained lead to clinically equivalent global dose distributions. Thus, this independent monitor unit calculation method for step-and-shoot IMRT is validated and can therefore be used in a clinical routine. It would be possible to consider applying a similar method for other treatment modalities, such as for instance tomotherapy or volumetric modulated arc therapy.

Covariance Matrix Estimation and Mean-Variance Optimization in application to International Diversification

Tutkimus keskittyy kansainväliseen hajauttamiseen suomalaisen sijoittajan näkökulmasta. Tutkimuksen toinen tavoite on selvittää tehostavatko uudet kovarianssimatriisiestimaattorit minimivarianssiportfolion optimointiprosessia. Tavallisen otoskovarianssimatriisin lisäksi optimoinnissa käytetään kahta kutistusestimaattoria ja joustavaa monimuuttuja-GARCH(1,1)-mallia. Tutkimusaineisto koostuu Dow Jonesin toimialaindekseistä ja OMX-H:n portfolioindeksistä. Kansainvälinen hajautusstrategia on toteutettu käyttäen toimialalähestymistapaa ja portfoliota optimoidaan käyttäen kahtatoista komponenttia. Tutkimusaieisto kattaa vuodet 1996-2005 eli 120 kuukausittaista havaintoa. Muodostettujen portfolioiden suorituskykyä mitataan Sharpen indeksillä. Tutkimustulosten mukaan kansainvälisesti hajautettujen investointien ja kotimaisen portfolion riskikorjattujen tuottojen välillä ei ole tilastollisesti merkitsevää eroa. Myöskään uusien kovarianssimatriisiestimaattoreiden käytöstä ei synnytilastollisesti merkitsevää lisäarvoa verrattuna otoskovarianssimatrisiin perustuvaan portfolion optimointiin.

Gas-liquid mass transfer in bubbly flow: Estimation of mass transfer, bubble size and reactor performance in various applications

Gas-liquid mass transfer is an important issue in the design and operation of many chemical unit operations. Despite its importance, the evaluation of gas-liquid mass transfer is not straightforward due to the complex nature of the phenomena involved. In this thesis gas-liquid mass transfer was evaluated in three different gas-liquid reactors in a traditional way by measuring the volumetric mass transfer coefficient (kLa). The studied reactors were a bubble column with a T-junction two-phase nozzle for gas dispersion, an industrial scale bubble column reactor for the oxidation of tetrahydroanthrahydroquinone and a concurrent downflow structured bed.The main drawback of this approach is that the obtained correlations give only the average volumetric mass transfer coefficient, which is dependent on average conditions. Moreover, the obtained correlations are valid only for the studied geometry and for the chemical system used in the measurements. In principle, a more fundamental approach is to estimate the interfacial area available for mass transfer from bubble size distributions obtained by solution of population balance equations. This approach has been used in this thesis by developing a population balance model for a bubble column together with phenomenological models for bubble breakage and coalescence. The parameters of the bubble breakage rate and coalescence rate models were estimated by comparing the measured and calculated bubble sizes. The coalescence models always have at least one experimental parameter. This is because the bubble coalescence depends on liquid composition in a way which is difficult to evaluate using known physical properties. The coalescence properties of some model solutions were evaluated by measuring the time that a bubble rests at the free liquid-gas interface before coalescing (the so-calledpersistence time or rest time). The measured persistence times range from 10 msup to 15 s depending on the solution. The coalescence was never found to be instantaneous. The bubble oscillates up and down at the interface at least a coupleof times before coalescence takes place. The measured persistence times were compared to coalescence times obtained by parameter fitting using measured bubble size distributions in a bubble column and a bubble column population balance model. For short persistence times, the persistence and coalescence times are in good agreement. For longer persistence times, however, the persistence times are at least an order of magnitude longer than the corresponding coalescence times from parameter fitting. This discrepancy may be attributed to the uncertainties concerning the estimation of energy dissipation rates, collision rates and mechanisms and contact times of the bubbles.

Deposición transversal de líquido de las boquillas de doble abanico TTJ60-11004 y TTJ60-11002 en distintas condiciones operacionales

El objetivo de este trabajo fue el de evaluar la deposición transversal de caldo de las boquillas pulverizadoras de doble abanico TTJ60-11004 y TTJ60-11002 en distintas condiciones operacionales. Se utilizaron 5 muestras de cada boquilla pulverizadora siendo considerada cada unidad, una repetición. La distribución de caldo fue evaluada por medio de una mesa de evaluación de distribución construida de acuerdo con la norma ISO 56821. Se evaluó el perfil de distribución individual, la distribución volumétrica simulada de la superposición de los chorros por medio del coeficiente de variación (CV%) de los volúmenes colectados, el caudal y el ángulo de abertura de los chorros. Las condiciones operacionales fueron: presión de trabajo de 200, 300 y 400 Kpa, altura de 30, 40 y 50 cm en relación al blanco y espaciamiento entre boquillas simulados en Software (Microsoft Excel) entre 45 y 100 cm. Las boquillas presentaron perfil individual descontinuo con la mayor deposición de líquido en la región central y reducción del volumen gradual en dirección a las extremidades. El aumento de la presión promovió alargamiento del perfil y de la franja de aplicación. Las boquillas proporcionaron perfil uniforme que dependió del espaciamiento entre las boquillas, con valores menores con reducción en el espaciamiento y en presiones mayores. El caudal y el ángulo del chorro aumentaron con el incremento en la presión.

Distribuição volumétrica e espectro de gotas de pontas de pulverização de baixa deriva

Objetivou-se neste trabalho avaliar a distribuição volumétrica e o espectro de gotas das pontas de pulverização de baixa deriva TTI110015, AI110015 e AVI11001 sob diferentes condições operacionais. A distribuição volumétrica foi determinada em bancada de ensaios padronizada analisando o coeficiente de variação (CV%) de uma barra simulada em computador, utilizando pressões de 200, 300 e 400 kPa, altura de 30, 40 e 50 cm em relação à bancada e espaçamento entre pontas de 40 a 100 cm. O espectro de gotas foi produzido utilizando-se apenas água como calda em um analisador de partículas em meio aquoso, nas pressões de 200, 300 e 400 kPa. Foram avaliados o DMV, a porcentagem de gotas com diâmetro inferior a 100 µm (%100 µm) e a amplitude relativa (AR). As pontas proporcionaram perfil descontínuo nas pressões de 300 e 400 kPa e uniforme a 200 kPa. Na pressão de 200 kPa, as pontas foram adequadas apenas para aplicação em faixa, e a 300 e 400 kPa, apenas para área total. Ocorreu menor CV (abaixo de 7%) com a maior pressão de trabalho e menor espaçamento entre pontas. À medida que se aumentou a pressão de trabalho, reduziu-se o DMV. As pontas TTI110015 e AI110015 em todas as pressões e a ponta AVI11001 na pressão de 200 kPa produziram gotas extremamente grossas e gotas grossas nas pressões de 300 e 400 kPa apenas para a ponta AVI11001. As pontas proporcionaram baixos valores de amplitude relativa (AR) e gotas de tamanho uniforme, bem como produziram baixa porcentagem de gotas menores que 100 µm, principalmente TTI110015 e AI110015, com menor risco de deriva.

Lajitteluparametrit korkeakappaisessa sellulinjassa

Tutkimustyön tarkoituksena oli selvittää Tainionkosken sellutehtaan vuonna 2001 uudistetun kuitulinjan prosessin vaikutusta kuumajauhatukseen, kuumalajitteluun, pesutulokseen ja hienolajitteluun. Työn tavoitteena oli löytää ja todentaa optimaalinen ajotapa lopputuotteen eli Tainionkosken kartonkitehtaan kartongin kannalta pesussa, kuidutuksessa, kuumalajittelussa ja hienolajittelussa. Ennen kuitulinjan uudistusta kartoitettiin tilanne kuumajauhatuksessa ja kuumalajittelussa ennen prosessimuutoksia. Kartoituksessa havaittiin, että kuumalajittelu ja kuumakuidutus toimivat parhaiten puhtaan jauhatusenergian ollessa n. 18 kWh/ADT, sekä tilavuusmääräisen ja massavirtamääräisen rejektisuhteen ollessa n. 30 %.Uuden pesemön valmistumisen jälkeen tutkittiin kappatason ja energiatason vaikutusta kuumalajitteluun, kuumakuidutukseen ja pesutulokseen. Tutkimuksessa todettiin tikkupitoisuuksien kasvavan kappatason kohoamisen seurauksena. Kuumajauhimen syöttösakeus kasvoi kappatason noustua, koska prosessimittaus ei huomioinut sakeuden kasvua ja tällöin jauhimen laimennusveden määrä jäi liian vähäiseksi. Korkean kapan seurauksena keitosta tulevien suurien partikkelien määrä lisääntyi. Kuumajauhatuksessa korkeampi kappaluku merkitsi hienoaineen lisääntymistä jauhetussa massassa. Tämän seurauksena kuidutetun massan suotautumisvastus kasvoi kappatason kohottua. Uuden prosessin kuumajauhatukseen tuleva massa on jo pesty 4-vaiheisella DD-pesurilla. Puhtaampi massa kuumajauhatuksessa ja kuumalajittelussa on merkinnyt jauhimen tikkureduktion paranemista, mutta samalla kuumalajittimen tikkujen puhdistustehokkuus on heikentynyt. Laboratoriomittausten mukaan kappatason kasvu huonontaa pesutulosta uudessa pesemössä. Uuden hienolajittamon suorituskykyä määritettiin taseiden avulla. Vanhan lajittamon toiminnassa huomattiin puutteita siinä, että 2-portaan lajittimen 1-portaan syöttöön tulevan rejektivirran tikkupitoisuus oli suurempi mitä tikkupitoisuus 1-portaan syöttövirrassa. Uudessa lajittamossa molempien virtausten tikkupitoisuudet olivat lähes samat. Kokonaisuudessaan hienolajittamon toiminta havaittiin hyväksi. Pesemö ja hienolajittelu toimivat kokeiden perusteella parhaiten lähellä mitoitettua maksimituotantoa 700 ADT/d.

Biphasic response of a tecto-mesencephalic pilocytic astrocytoma after Gamma Knife surgery - A case report.

Biphasic response (shrinkage-regrowth-shrinkage) of tumors has never previously been reported in the postoperative course, neither after microsurgery, nor after Gamma Knife surgery (GKS). We present the case of an adult with dorsal midbrain syndrome resulting from a pilocytic astrocytoma centered on the mesencephalic tectum. The tumor extended to the third ventricle and the thalamus. Initially, due to tumor growth, a biopsy was performed and histology established. Later, a ventriculocisternostomy for obstructive hydrocephalus was performed. Finally, GKS was performed, as the tumor continued to grow. After GKS, the lesion exhibited a biphasic response, with a major shrinkage at 3 months, regrowth within the target volume at 6 and 9 months and a second phase of important shrinkage at 12 months, which persisted for the next two years. The possible mechanisms for this particular response pattern are discussed.