Unified large and small signal non-quasi-static model for long channel symmetric DG MOSFET

We propose a unified model for large signal and small signal non-quasi-static analysis of long channel symmetric double gate MOSFET. The model is physics based and relies only on the very basic approximation needed for a charge-based model. It is based on the EKV formalism Enz C, Vittoz EA. Charge based MOS transistor modeling. Wiley; 2006] and is valid in all regions of operation and thus suitable for RF circuit design. Proposed model is verified with professional numerical device simulator and excellent agreement is found. (C) 2010 Elsevier Ltd. All rights reserved.

Length-independent voltage fluctuations in small conductors

The mean-squared voltage fluctuation of a disordered conductor of lengthL smaller than the phase coherence lengthL ϕ, is independent of the distance between the probes. We obtain this result using the voltage additivity and the known results for the conductance fluctuation. Our results complement the recent theoretical and experimental findings.

Non-small cell lung cancer : studies on pathogenesis, tumour targeting and treatment outcomes

Lung cancer accounts for more cancer-related deaths than any other cancer. In Finland, five-year survival ranges from 8% to 13%. The main risk factor for lung cancer is long-term cigarette smoking, but its carcinogenesis requires several other factors. The aim of the present study was to 1) evaluate post-operative quality of life, 2) compare clinical outcomes between minimally invasive and conventional open surgery, 3) evaluate the role of oxidative stress in the carcinogenesis of non-small lung cancer (NSCLC), and 4) to identify and characterise targeted agents for therapeutic and diagnostic use in surgery. For study I, pneumonectomy patients replied to 15D quality of life and baseline dyspnea questionnaires. Study III involved a prospective quality of life assessment using the 15D questionnaire after lobectomy or bi-lobectomy. Study IV was a retrospective comparison of clinical outcomes between 212 patients treated with open thoracotomy and 116 patients who underwent a minimally invasive technique. Study II measured parameters of oxidative metabolism (myeloperoxidase activity, glutathione content and NADPH oxidase activity) and DNA adducts. Study V employed the phage display method and identified a core motif for homing peptides. This method served in cell-binding, cell-localisation, and biodistribution studies. Following both pneumonectomy and lobectomy, NSCLC patients showed significantly decreased long-term quality of life. No significant correlation was noted between post-operative quality of life and pre-operative pulmonary function tests. Women suffered more from increased dyspnea after pneumonectomy which was absent after lobectomy or bi-lobectomy. Patients treated with video-assisted thoracoscopy showed significantly decreased morbidity and shorter periods of hospitalization than did open surgery patients. This improvement was achieved even though the VATS patients were older and suffered more comorbid conditions and poorer pulmonary function. No significant differences in survival were noted between these two groups. An increase in NADPH oxidase activity was noted in tumour samples of both adenocarcinoma and squamous cell carcinoma. This increase was independent from myeloperoxidase activity. Elevated glutathione content was noted in tumour tissue, especially in adenocarcinoma. After panning the clinical tumour samples with the phage display method, an amino acid sequence of ARRPKLD, the Thx, was chosen for further analysis. This method proved selective of tumour tissue in both in vitro and in vivo cell-binding assay, and biodistribution showed tumour accumulation. Because of the significantly reduced quality of life following pneumonectomy, other operative strategies should be implemented as an alternative (e.g. sleeve-lobectomy). To treat this disease, implementation of a minimally invasive surgical technique is safe, and the results showed decreased morbidity and a shorter period of hospitalisation than with thoracotomy. This technique may facilitate operative treatment of elderly patients with comorbid conditions who might otherwise be considered inoperable. Simultaneous exposure to oxidative stress and altered redox states indicates the important role of oxidative stress in the pathogenesis and malignant transformation of NSCLC. The studies showed with great specificity and with favourable biodistribution that Thx peptide is specific to NSCLC tumours. Thx thus shows promise in imaging, targeted therapy, and monitoring of treatment response.

Stabilization of the bio-membrane by small molecules: interaction of trehalose with the phospholipid bilayer

Anhydrobiotic organisms undergo periods of acute dehydration during their life cycle. It is of interest to understand how the biomembrane remains intact through such stress. A disaccharide, trehalose, which is metabolised during anhydrobiosis is found to prevent disruption of model membrane systems. Molecular modelling techniques are used to investigate the possible mode of interaction of trehalose with a model monolayer. The objective is to maximise hydrogen bonding between the two systems. A phospholipid matrix consisting of 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) is chosen to represent the monolayer. The crystal structure of DMPC reveals that there are two distinct conformers designated as A and B. An expansion of the monolayer, coplanar with its surface, results in the trehalose molecule being accommodated in a pocket formed by four B conformers. One glucose ring of the sugar rests on the hydrophobic patch provided by the choline methyls of an A conformer. Five hydrogen bonds are formed involving the phosphate oxygens of three of the surrounding B conformers. The model will be discussed with reference to relevant experimental data on the interaction.

Host-parasitoid relationship in different Cotesia melitaearum and Melitaea cinxia populations around the Baltic Sea

The relationship between hosts and parasites is one of the most studied interactions between living organisms, and it is both universal and common in nature. Parasitoids are special type of parasites whose offspring develop attached to or within a single host organism that it ultimately consumes and kills. Hosts are arthropods and most parasitoids belong to the insect order Hymenoptera. For almost two decades metapopulation research on the Glanville fritillary butterfly (Melitaea cinxia) has been conducted in the Åland Islands, Finland. The studies have been concerned with the population dynamics, evolution, genetics, behavior, natural history and life history characteristics of M. cinxia, as well as with species interacting with the butterfly. The parasitoids of M. cinxia have been under long term studies and much has been learned about specific host-parasitoid interactions during the past decade. The research for this Master s thesis was done in the Åland Islands during summer 2010. I conducted a reciprocal transplant style experiment in order to compare the performance of host butterflies (M. cinxia) under attack by different parasitoid wasps (C. melitaearum). I used hosts and parasitoids from five origins around the Baltic Sea: Öland, Uppland, Åland, Saaremaa and Pikku-Tytärsaari. The host-parasitoid relationship was studied in terms of host susceptibility and parasitoid virulence, addressing specifically the possible effects of inbreeding and local adaptation of both parasitoids and their hosts. I compared various factors such as host defence ratio, parasitoid development rate, cocoon production rate etc. I also conducted a small scale C. melitaearum egg development experiment and C. melitaearum external morphology comparison between different parasitoid populations. The results show that host resistance and parasitoid virulence differ between both host and parasitoid populations. For example, Öland hosts were most susceptible to parasitoids and especially vulnerable to Pikku-Tytärsaari wasps. Pikku-Tytärsaari wasps were most successful in terms of parasitoids virulence and efficiency except in Saaremaa hosts, where the wasp did not succeed. Saaremaa hosts were resistant except towards Åland parasitoids. I did not find any simple pattern concerning host resistance and parasitoid virulence between inbred and outbred populations. Also, the effect of local adaptation was not detected, perhaps because metapopulation processes disturb local adaptation of the studied populations. Morphological comparisons showed differences between studied wasp populations and sexual dimorphism was obvious with females being bigger that males. There were also interesting differences among populations in male and female wing shapes. The results raise many further questions. Especially interesting were Pikku-Tytärsaari wasps that did well in terms of efficiency and virulence. Pikku-Tytärsaari is a small, isolated island in the Gulf of Finland and both the host and parasitoids are extremely inbred. For the host and parasitoid to persist in the island, the host has to have some mechanisms to escape the parasitoid. Further research will be done on the subject to discover the mechanisms of Pikku-Tytärsaari host s ability to escape parasitism. Also, genetic analyses will be conducted in the near future to determine the relatedness of used C. melitaearum populations.

Peritoneal dialysis and neurological outcome in infants and small children

Although improved outcomes for children on peritoneal dialysis (PD) have been seen in recent years, the youngest patients continue to demonstrate inferior growth, more frequent infections, more neurological sequelae, and higher mortality compared to older children. Also, maintain-ing normal intravascular volume status, especially in anuric patients, has proven difficult. This study was designed to treat and monitor these youngest PD patients, which are relatively many due to the high prevalence of congenital nephrotic syndrome of the Finnish type (CNF, NPHS1) in Finland, with a strict protocol, to evaluate the results and to improve metabolic balance, growth, and development. A retrospective analysis of 23 children under two years of age at onset of PD, treated between 1995 and 2000, was performed to obtain a control population for our prospective PD study. Respectively, 21 patients less than two years of age at the beginning of PD were enrolled in prospective studies between 2001 and 2005. Medication for uremia and nutrition were care-fully adjusted during PD. Laboratory parameters and intravascular volume status were regu-larly analyzed. Growth was analyzed and compared with midparental height. In a prospective neurological study, the risk factors for development and the neurological development was determined. Brain images were surveyed. Hearing was tested. In a retrospective neurological study, the data of six NPHS1 patients with a congruent neurological syndrome was analyzed. All these patients had a serious dyskinetic cerebral palsy-like syndrome with muscular dysto-nia and athetosis (MDA). They also had a hearing defect. Metabolic control was mainly good in both PD patient groups. Hospitalization time shortened clearly. The peritonitis rate diminished. Hypertension was a common problem. Left ventricular hypertrophy decreased during the prospective study period. None of the patients in either PD group had pulmonary edema or dialysis-related seizures. Growth was good and catch-up growth was documented in most patients in both patient groups during PD. Mortality was low (5% in prospective and 9% in retrospective PD patients). In the prospective PD patient group 11 patients (52%) had some risk factor for their neuro-development originating from the predialysis period. The neurological problems, detected be-fore PD, did not worsen during PD and none of the patients developed new neurological com-plications during PD. Brain infarcts were detected in four (19%) and other ischemic lesions in three patients (14%). At the end of this study, 29% of the prospectively followed patients had a major impairment of their neurodevelopment and 43% only minor impairment. In the NPHS1+MDA patients, no clear explanation for the neurological syndrome was found. The brain MRI showed increased signal intensity in the globus pallidus area. Kernic-terus was contemplated to be causative in the hypoproteinemic newborns but it could not be proven. Mortality was as high as 67%. Our results for young PD patients were promising. Metabolic control was acceptable and growth was good. However, the children were significantly smaller when compared to their midparental height. Although many patients were found to have neurological impairment at the end of our follow-up period, PD was a safe treatment whereby the neurodevelopment did not worsen during PD.

Impact of energy quantisation in single electron transistor island on hybrid complementary metal oxide semiconductor-single electron transistor integrated circuits

For the first time, the impact of energy quantisation in single electron transistor (SET) island on the performance of hybrid complementary metal oxide semiconductor (CMOS)-SET transistor circuits has been studied. It has been shown through simple analytical models that energy quantisation primarily increases the Coulomb Blockade area and Coulomb Blockade oscillation periodicity of the SET device and thus influences the performance of hybrid CMOS-SET circuits. A novel computer aided design (CAD) framework has been developed for hybrid CMOS-SET co-simulation, which uses Monte Carlo (MC) simulator for SET devices along with conventional SPICE for metal oxide semiconductor devices. Using this co-simulation framework, the effects of energy quantisation have been studied for some hybrid circuits, namely, SETMOS, multiband voltage filter and multiple valued logic circuits. Although energy quantisation immensely deteriorates the performance of the hybrid circuits, it has been shown that the performance degradation because of energy quantisation can be compensated by properly tuning the bias current of the current-biased SET devices within the hybrid CMOS-SET circuits. Although this study is primarily done by exhaustive MC simulation, effort has also been put to develop first-order compact model for SET that includes energy quantisation effects. Finally, it has been demonstrated that one can predict the SET behaviour under energy quantisation with reasonable accuracy by slightly modifying the existing SET compact models that are valid for metallic devices having continuous energy states.

Mathematical modelling of groundwater pollution in a small heterogeneous aquifer at Kärkölä, southern Finland

Yhteenveto: Kärkölän likaantuneen pohjavesialueen matemaattinen mallinnus

A Non Quasi-Static Small Signal Model for Long Channel Symmetric DG MOSFET

We propose a compact model for small signal non quasi static analysis of long channel symmetric double gate MOSFET The model is based on the EKV formalism and is valid in all regions of operation and thus suitable for RF circuit design Proposed model is verified with professional numerical device simulator and excellent agreement is found well beyond the cut-off frequency

Relaxation dominated by inertia: Solvation dynamics of a small ion in a dipolar solvent

It is shown from an analytical theory that the solvation dynamics of a small ion can be controlled largely by the inertial response of the dipolar solvent when the liquid is in the underdamped limit. It is also shown that this inertial response arises primarily from the long wavelength (with wavevector k≃0) processes which have a collective excitation-like behaviour. The long time decay is dominated by the processes occurring at molecular lengthscales. The theoretical results are in good agreement with recent computer simulation results.

Historical considerations and evolution of the forest policies for small woodlot owners of Quebec.

XVIII IUFRO World Congress, Ljubljana 1986.

Polarization studies in electromagnetic scattering by small Solar-system particles

In remote-sensing studies, particles that are comparable to the wavelength exhibit characteristic features in electromagnetic scattering, especially in the degree of linear polarization. These features vary with the physical properties of the particles, such as shape, size, refractive index, and orientation. In the thesis, the direct problem of computing the unknown scattered quantities using the known properties of the particles and the incident radiation is solved at both optical and radar spectral regions in a unique way. The internal electromagnetic fields of wavelength-scale particles are analyzed by using both novel and established methods to show how the internal fields are related to the scattered fields in the far zone. This is achieved by using the tools and methods that were developed specifically to reveal the internal field structure of particles and to study the mechanisms that relate the structure to the scattering characteristics of those particles. It is shown that, for spherical particles, the internal field is a combination of a forward propagating wave with the apparent wavelength determined by the refractive index of the particle, and a standing wave pattern with the apparent wavelength the same as for the incident wave. Due to the surface curvature and dielectric nature of the particle, the incident wave front undergoes a phase shift, and the resulting internal wave is focused mostly at the forward part of the particle similar to an optical lens. This focusing is also seen for irregular particles. It is concluded that, for both spherical and nonspherical particles, the interference at the far field between the partial waves that originate from these concentrated areas in the particle interior, is responsible for the specific polarization features that are common for wavelength-scale particles, such as negative values and local extrema in the degree of linear polarization, asymmetry of the phase function, and enhancement of intensity near the backscattering direction. The papers presented in this thesis solve the direct problem for particles with both simple and irregular shapes to demonstrate that these interference mechanisms are common for all dielectric wavelength-scale particles. Furthermore, it is shown that these mechanisms can be applied to both regolith particles in the optical wavelengths and hydrometeors at microwave frequencies. An advantage from this kind of study is that it does not matter whether the observation is active (e.g., polarimetric radar) or passive (e.g., optical telescope). In both cases, the internal field is computed for two mutually perpendicular incident polarizations, so that the polarization characteristics can then be analyzed according to the relation between these fields and the scattered far field.

Poststroke survival and ischemic stroke recurrence : the cerebral small-vessel disease perspective

The aim of the present study was to investigate the influence of different manifestations of cerebral SVD on poststroke survival and ischemic stroke recurrence in long-term follow-up. The core imaging features of small-vessel disease (SVD) are confluent and extensive white matter changes (WMC) and lacunar infarcts. These are associated with minor motor deficits but a major negative influence on cognition, mood, and functioning in daily life, resulting from small-vessel lesions in the fronto-subcortical brain network. These sub-studies were conducted as part of the Helsinki Stroke Aging Memory (SAM) study. The SAM cohort consisted of 486 consecutive patients aged 55 to 85 years who were admitted to Helsinki University Central Hospital with acute ischemic stroke. The study included comprehensive clinical, neuropsychological, psychiatric and radiological assessment three months poststroke. The patients were followed up up for 12 years using extensive national registers. The effect of different manifestations of cerebral SVD on poststroke survival and stroke recurrence was analyzed controlling for factors such as age, education, and cardiovascular risk factors. Poststroke dementia and cognitive impairment relate to poor long-term survival. In particular, deficits in executive functions as well as visuospatial and constructional abilities predict poor outcome. The predictive value of cognitive deficits is further underlined by the finding that depression-executive dysfunction syndrome (DES), but not depression in itself, is associated with poor poststroke survival. Delirium is not independently associated with increased risk for long-term poststroke mortality, although it is associated with poststroke dementia. Furthermore, acute index stroke attributable to SVD is associated with poorer long-term survival and a higher risk for cardiac death than other stroke subtypes. Severe WMC, a surrogate of SVD, is independently related to an increased risk of stroke recurrence at five years. In summary, cognitive poststroke outcomes reflecting changes in the executive network brain, and the presence of cerebral SVD are important determinants of poststroke mortality and ischemic stroke recurrence, regardless of whether SVD is the cause of the index stroke or a condition concurrent to some other etiology.