A videolaparoscopia no diagnóstico e tratamento do schwannoma abdominal

The authors present two patients with solid tumours (benign Schwannoma), which were found during abdominal ultra-sonography. One of them was located adjacent to the hepatic artery, near its origin at the celiac axis. In the second case the tumor was found in the diafragm. Both of them were well limited and non-invasive (benign characteristics). The removal -for diagnosis and treatment - was done using videolaparoscopy. They emphasize the huge advantages of this new diagnostic and therapeutical modality.

Edema pulmonar de reexpansão tratado com ventilação não invasiva: relato de caso

The authors report a case of Reexpansion Pulmonary Edema (RPE) seen at Hospital de Pronto Socorro de Porto Alegre 3 hours after drainage of spontaneous pneumothorax. The patient presented a unilateral pneumothorax with one-week duration. After pleural drainage respiratory failure occured being managed at the Intensive Care Unit with non-invasive positive pressure ventilation through facial mask. The patient had favorable outcome and was discharged asymtomatic after 72 hours.

Flexible multibody approach in bone strain estimation during physical activity:

Bone strain plays a major role as the activation signal for the bone (re)modeling process, which is vital for keeping bones healthy. Maintaining high bone mineral density reduces the chances of fracture in the event of an accident. Numerous studies have shown that bones can be strengthened with physical exercise. Several hypotheses have asserted that a stronger osteogenic (bone producing) effect results from dynamic exercise than from static exercise. These previous studies are based on short-term empirical research, which provide the motivation for justifying the experimental results with a solid mathematical background. The computer simulation techniques utilized in this work allow for non-invasive bone strain estimation during physical activity at any bone site within the human skeleton. All models presented in the study are threedimensional and actuated by muscle models to replicate the real conditions accurately. The objective of this work is to determine and present loading-induced bone strain values resulting from physical activity. It includes a comparison of strain resulting from four different gym exercises (knee flexion, knee extension, leg press, and squat) and walking, with the results reported for walking and jogging obtained from in-vivo measurements described in the literature. The objective is realized primarily by carrying out flexible multibody dynamics computer simulations. The dissertation combines the knowledge of finite element analysis and multibody simulations with experimental data and information available from medical field literature. Measured subject-specific motion data was coupled with forward dynamics simulation to provide natural skeletal movement. Bone geometries were defined using a reverse engineering approach based on medical imaging techniques. Both computed tomography and magnetic resonance imaging were utilized to explore modeling differences. The predicted tibia bone strains during walking show good agreement with invivo studies found in the literature. Strain measurements were not available for gym exercises; therefore, the strain results could not be validated. However, the values seem reasonable when compared to available walking and running invivo strain measurements. The results can be used for exercise equipment design aimed at strengthening the bones as well as the muscles during workout. Clinical applications in post fracture recovery exercising programs could also be the target. In addition, the methodology introduced in this study, can be applied to investigate the effect of weightlessness on astronauts, who often suffer bone loss after long time spent in the outer space.

Imaging of Tumour Microenvironment for the Planning of Oncological Therapies Using Positron Emission Tomography

Tumour cells differ from normal tissue cells in several important ways. These differences, like for example changed energy metabolism, result in altered microenvironment of malignant tumours. Non-invasive imaging of tumour microenvironment has been at the centre of intense research recently due to the important role that this changed environement plays in the development of malignant tumours and due to the role it plays in the treatment of these tumours. In this respect, perhaps the most important characteristics of the tumour microenvironment from this point of view are the lack of oxygen or hypoxia and changes in blood flow (BF). The purpose of this thesis was to investigate the processes of energy metabolism, BF and oxygenation in head and neck cancer and pancreatic tumours and to explore the possibilities of improving the methods for their quantification using positron emission tomography (PET). To this end [18F]EF5, a new PET tracer for detection of tumour hypoxia was investigated. Favourable uptake properties of the tracer were observed. In addition, it was established that the uptake of this tracer does not correlate with the uptake of existing tracers for the imaging of energy metabolism and BF, so the information about the presence of tissue hypoxia cannot therefore be obtained using tracers such as [18F]FDG or [15O]H2O. These results were complemented by the results of the follow-up study in which it was shown that the uptake of [18F]EF5 in head and neck tumours prior to treatment is also associated with the overall survival of the patients, indicating that tumour hypoxia is a negative prognostic factor and might be associated with therapeutic resistance. The influences of energy metabolism and BF on the survival of patients with pancreatic cancer were investigated in the second study. The results indicate that the best predictor of survival of patients with pancreatic cancer is the relationship between energy metabolism and BF. These results suggest that the cells with high metabolic activity in a hypoperfused tissue have the most aggressive phenotype.

Characterisation of Laser Beam and Paper Material Interaction

It is known already from 1970´s that laser beam is suitable for processing paper materials. In this thesis, term paper materials mean all wood-fibre based materials, like dried pulp, copy paper, newspaper, cardboard, corrugated board, tissue paper etc. Accordingly, laser processing in this thesis means all laser treatments resulting material removal, like cutting, partial cutting, marking, creasing, perforation etc. that can be used to process paper materials. Laser technology provides many advantages for processing of paper materials: non-contact method, freedom of processing geometry, reliable technology for non-stop production etc. Especially packaging industry is very promising area for laser processing applications. However, there are only few industrial laser processing applications worldwide even in beginning of 2010´s. One reason for small-scale use of lasers in paper material manufacturing is that there is a shortage of published research and scientific articles. Another problem, restraining the use of laser for processing of paper materials, is colouration of paper material i.e. the yellowish and/or greyish colour of cut edge appearing during cutting or after cutting. These are the main reasons for selecting the topic of this thesis to concern characterization of interaction of laser beam and paper materials. This study was carried out in Laboratory of Laser Processing at Lappeenranta University of Technology (Finland). Laser equipment used in this study was TRUMPF TLF 2700 carbon dioxide laser that produces a beam with wavelength of 10.6 μm with power range of 190-2500 W (laser power on work piece). Study of laser beam and paper material interaction was carried out by treating dried kraft pulp (grammage of 67 g m-2) with different laser power levels, focal plane postion settings and interaction times. Interaction between laser beam and dried kraft pulp was detected with different monitoring devices, i.e. spectrometer, pyrometer and active illumination imaging system. This way it was possible to create an input and output parameter diagram and to study the effects of input and output parameters in this thesis. When interaction phenomena are understood also process development can be carried out and even new innovations developed. Fulfilling the lack of information on interaction phenomena can assist in the way of lasers for wider use of technology in paper making and converting industry. It was concluded in this thesis that interaction of laser beam and paper material has two mechanisms that are dependent on focal plane position range. Assumed interaction mechanism B appears in range of average focal plane position of 3.4 mm and 2.4 mm and assumed interaction mechanism A in range of average focal plane position of 0.4 mm and -0.6 mm both in used experimental set up. Focal plane position 1.4 mm represents midzone of these two mechanisms. Holes during laser beam and paper material interaction are formed gradually: first small hole is formed to interaction area in the centre of laser beam cross-section and after that, as function of interaction time, hole expands, until interaction between laser beam and dried kraft pulp is ended. By the image analysis it can be seen that in beginning of laser beam and dried kraft pulp material interaction small holes off very good quality are formed. It is obvious that black colour and heat affected zone appear as function of interaction time. This reveals that there still are different interaction phases within interaction mechanisms A and B. These interaction phases appear as function of time and also as function of peak intensity of laser beam. Limit peak intensity is the value that divides interaction mechanism A and B from one-phase interaction into dual-phase interaction. So all peak intensity values under limit peak intensity belong to MAOM (interaction mechanism A one-phase mode) or to MBOM (interaction mechanism B onephase mode) and values over that belong to MADM (interaction mechanism A dual-phase mode) or to MBDM (interaction mechanism B dual-phase mode). Decomposition process of cellulose is evolution of hydrocarbons when temperature is between 380- 500°C. This means that long cellulose molecule is split into smaller volatile hydrocarbons in this temperature range. As temperature increases, decomposition process of cellulose molecule changes. In range of 700-900°C, cellulose molecule is mainly decomposed into H2 gas; this is why this range is called evolution of hydrogen. Interaction in this range starts (as in range of MAOM and MBOM), when a small good quality hole is formed. This is due to “direct evaporation” of pulp via decomposition process of evolution of hydrogen. And this can be seen can be seen in spectrometer as high intensity peak of yellow light (in range of 588-589 nm) which refers to temperature of ~1750ºC. Pyrometer does not detect this high intensity peak since it is not able to detect physical phase change from solid kraft pulp to gaseous compounds. As interaction time between laser beam and dried kraft pulp continues, hypothesis is that three auto ignition processes occurs. Auto ignition of substance is the lowest temperature in which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark. Three auto ignition processes appears in range of MADM and MBDM, namely: 1. temperature of auto ignition of hydrogen atom (H2) is 500ºC, 2. temperature of auto ignition of carbon monoxide molecule (CO) is 609ºC and 3. temperature of auto ignition of carbon atom (C) is 700ºC. These three auto ignition processes leads to formation of plasma plume which has strong emission of radiation in range of visible light. Formation of this plasma plume can be seen as increase of intensity in wavelength range of ~475-652 nm. Pyrometer shows maximum temperature just after this ignition. This plasma plume is assumed to scatter laser beam so that it interacts with larger area of dried kraft pulp than what is actual area of beam cross-section. This assumed scattering reduces also peak intensity. So result shows that assumably scattered light with low peak intensity is interacting with large area of hole edges and due to low peak intensity this interaction happens in low temperature. So interaction between laser beam and dried kraft pulp turns from evolution of hydrogen to evolution of hydrocarbons. This leads to black colour of hole edges.

Influence of the bipartite scrotum on the testicular and scrotal temperatures in goats

The influence of the scrotal bipartition and of the year period on the scrotal-testicular thermal regulation was evaluated in male goats raised in Piaui State, Brazil. Eighteen male goats at mating age were accomplished in this study and arranged into three Groups (6 animals each) obeying the classification as goats presenting no scrotal bipartition (Group I), goats showing scrotal bipartition at 50% of the testicular length (Group II), and goats with more than 50% of scrotal bipartition (Group III). The scrotal, testicular and spermatic funiculi temperatures were evaluated invasively with the aid of a digital thermometer and non-invasive with a pyrometer in the proximal, medial and distal portion. The data were acquired during the dry (October-November) and rainy (February-March) period of the year, measured in two shifts: morning (6h00-7h00) and afternoon (14h00-15h00). The results were submitted to variance analysis (ANOVA) following the SNK test for average comparison (p<0.05). The year period interfered on the scrotal-testicular thermal regulation, due to increased temperatures of the scrotal, testicular and spermatic funiculi during the dry period in comparison with the rainy period. The bipartition level was also a factor which contributed to the influence of scrotal-testicular temperature regulation, due to lower average scrotal-testicular temperature rates observed during both periods in the goats with higher levels of scrotal bipartition (>50%). It is possible to conclude that with the experimental conditions applied on this study, the level of scrotal bipartition and the climatic conditions interfere with the scrotal-testicular thermal regulation in goats.

Comparison of two methods for glucocorticoid evaluation in maned wolves

Analysis of faecal glucocorticoid metabolites provides a powerful noninvasive tool for monitoring adrenocortical activity in wild animals. However, differences regarding the metabolism and excretion of these substances make a validation for each species and sex investigated obligatory. Although maned wolves (Chrysocyon brachyurus) are the biggest canids in South America, their behaviour and physiology are poorly known and they are at risk in the wild. Two methods for measuring glucocorticoid metabolites in maned wolves were validated: a radio- and an enzyme immunoassay. An ACTH challenge was used to demonstrate that changes in adrenal function are reflected in faecal glucocorticoid metabolites. Our results suggest that both methods enable a reliable assessment of stress hormones in maned wolves avoiding short-term rises in glucocorticoid concentrations due to handling and restraint. These methods can be used as a valuable tool in studies of stress and conservation in this wild species.

Ultrasound call detection in capybara

The vocal repertoire of some animal species has been considered a non-invasive tool to predict distress reactivity. In rats ultrasound emissions were reported as distress indicator. Capybaras[ vocal repertoire was reported recently and seems to have ultrasound calls, but this has not yet been confirmed. Thus, in order to check if a poor state of welfare was linked to ultrasound calls in the capybara vocal repertoire, the aim of this study was to track the presence of ultrasound emissions in 11 animals under three conditions: 1) unrestrained; 2) intermediately restrained, and 3) highly restrained. The ultrasound track identified frequencies in the range of 31.8±3.5 kHz in adults and 33.2±8.5 kHz in juveniles. These ultrasound frequencies occurred only when animals were highly restrained, physically restrained or injured during handling. We concluded that these calls with ultrasound components are related to pain and restraint because they did not occur when animals were free of restraint. Thus we suggest that this vocalization may be used as an additional tool to assess capybaras[ welfare.

Motoneuronitautiin liittyvä hengitysvajaus: hengitystoiminnan ja energia-aineenvaihdunnan mittaaminen

Tavoitteet: Tämän tutkimussarjan tavoitteena oli tutkia hengitystoiminnan sekä energia-aineen¬vaihdunnan muutoksia motoneuronitautia (amyotrofinen lateraaliskleroosi, ALS) sairastavilla potilailla. Erityisenä mielenkiinnon kohteena olivat kotihoitoon soveltuvan hengityslaitteen vai¬kutus elinajan ennusteeseen sekä hengitysvajauksen etenemistä kuvaavien keuhkotoimintakokei¬den arviointi ALS-potilailla, epäsuoran kalorimetrian mittaustarkkuus ja perusaineenvaihdunnan (PAV) suuruus kajoavaa hengityslaitetta käyttävillä ALS-potilailla. Aineisto ja menetelmät: Kajoamattoman hengityslaitteen käytön ja iän vaikutusta elinajan en¬nusteeseen arvioitiin 84:llä ja hengitystoiminnan muutoksia 42 ALS-potilaalla. Epäsuoran kalo¬rimetrian mittaustarkkuutta kajoamatonta hengityslaitetta käytettäessä arvioitiin hereillä olevilla 12 vapaaehtoisella mieshenkilöllä. PAV:n suuruutta arvioitiin viidellä kajoavaa hengityslaitetta käyttävällä ALS-potilaalla. Osatöistä kaksi ensimmäistä olivat luonteeltaan havainnoivia (retros¬pektiivisiä) ja kaksi viimeistä seurantatutkimuksia (prospektiivisia). Tulokset: Alle 65-vuotiailla ALS-potilailla ei havaittu eroa elinajan ennusteessa kajoamaton¬ta hengityslaitetta käyttävien ja käyttämättömien potilaiden välillä. Sen sijaan yli 65-vuotiail¬la ALS-potilailla elinajan ennuste piteni merkittävästi kajoamatonta hengityslaitetta käyttävillä potilailla (elinaika diagnoosin jälkeen 22 vs. 8 kk, Hazard Ratio = 0.25, 95 % luottamusväli 0.11 – 0.55, p <0.001). ALS-potilailla, joilla kajoamaton hengityslaite katsottiin tarpeelliseksi kuuden kuukauden kuluessa diagnoosihetkestä, hengitystiheys osoittautui diagnoosihetkellä mer-kittävästi kiihtyneeksi (21/min) ja rintakehän liike merkittävästi alentuneeksi (2.9 cm) verrattuna ALS-potilaisiin, joille kajoamaton hengityslaite katsottiin tarpeelliseksi myöhemmin (16/min ja 4.0 cm). Kajoamattoman hengityslaitehoidon aikana keskimääräinen mitattu PAV vapaaehtoisilla miehillä oli 1858 kcal/vrk kun PAV ilman hengityslaitetta oli 1852 kcal/vrk, p = 0.8. Kajoavaa hengityslaitehoitoa käyttävien viiden ALS-potilaan keskimääräinen PAV vastaavalla mittausase¬telmalla mitattaessa oli 1130 kcal/vrk, kun vastaava PAV laskettuna viidellä eri laskentakaavalla oli 1700 kcal/vrk, p < 0.001. Johtopäätökset: Yli 65-vuotiailla ALS-potilailla, jotka eivät sopeutuneet kajoamattomaan hen¬gityslaitehoitoon, oli nelinkertainen riski menehtyä aiemmin kuin kajoamattomaan hengityslai¬tehoitoon sopeutuneilla ALS-potilailla. Hengitystiheys osoittautui merkittävästi kiihtyneeksi ja rintakehän liike alentuneeksi ALS-potilailla, joille kajoamaton hengityslaitehoito katsottiin ai¬heelliseksi kuuden kuukauden kuluessa diagnoosihetkestä. Kajoamattoman hengityslaitehoidon aikana mitattu PAV ei poikennut mitatusta PAV:sta itsenäisen hengityksen aikana. Näin ollen epäsuoraa kalorimetriamenetelmää voidaan käyttää luotettavasti PAV:n määrittämiseen käytet¬täessä samanaikaisesti kotihoitoon soveltuvaa hengityslaitehoitoa. Elämää ylläpitävää kajoavaa hengityslaitehoitoa käyttävien ALS-potilaiden PAV oli merkittävästi hidastunut laskennallisella menetelmällä arvioituun PAV verrattuna.

Compensatory enlargement of human coronary arteries identified by magnetic resonance imaging

The aim of the present study was to evaluate the role of magnetic resonance imaging (MRI) for the non-invasive detection of coronary abnormalities and specifically the remodeling process in patients with coronary artery disease (CAD). MRI was performed in 10 control healthy subjects and 26 patients with angiographically proven CAD of the right coronary (RCA) or left anterior descending (LAD) artery; 23 patients were within two months of acute coronary syndromes, and 3 had stable angina with a positive test for ischemia. Wall thickness (WT), vessel wall area (VWA), total vessel area (TVA), and luminal area (LA) were measured. There were significant increases in WT (mean ± SEM, RCA: 2.62 ± 0.75 vs 0.53 ± 0.15 mm; LAD: 2.21 ± 0.69 vs 0.62 ± 0.24 mm) and in VWA (RCA: 30.96 ± 17.57 vs 2.1 ± 1.2 mm²; LAD: 19.53 ± 7.25 vs 3.6 ± 2.0 mm²) patients compared to controls (P < 0.001 for each variable). TVA values were also greater in patients compared to controls (RCA: 44.56 ± 21.87 vs 12.3 ± 4.2 mm²; LAD: 31.89 ± 11.31 vs 17.0 ± 6.2 mm²; P < 0.001). In contrast, the LA did not differ between patients and controls for RCA or LAD. When the LA was adjusted for vessel size using the LA/TVA ratio, a significant difference was found: 0.33 ± 0.16 in patients vs 0.82 ± 0.09 in controls (RCA) and 0.38 ± 0.13 vs 0.78 ± 0.06 (LAD) (P < 0.001). As opposed to normal controls, positive remodeling was present in all patients with CAD, as indicated by larger VWA. We conclude that MRI detected vessel wall abnormalities and was an effective tool for the noninvasive evaluation of the atherosclerotic process and coronary vessel wall modifications, including positive remodeling that frequently occurs in patients with acute coronary syndromes.

Imaging Neuroinflammation in Progressive Multiple Sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system CNS), where inflammation and neurodegeneration lead to irreversible neuronal damage. In MS, a dysfunctional immune system causes auto‐reactive lymphocytes to migrate into CNS where they initiate an inflammatory cascade leading to focal demyelination, axonal degeneration and neuronal loss. One of the hallmarks of neuronal injury and neuroinflammation is the activation of microglia. Activated microglia are found not only in the focal inflammatory lesions, but also diffusely in the normal‐appearing white matter (NAWM), especially in progressive MS. The purine base, adenosine is a ubiquitous neuromodulator in the CNS and also participates in the regulation of inflammation. The effect of adenosine mediated via adenosine A2A receptors has been linked to microglial activation, whereas modulating A2A receptors may exert neuroprotective effects. In the majority of patients, MS presents with a relapsing disease course, later advancing to a progressive phase characterised by a worsening, irreversible disability. Disease modifying treatments can reduce the severity and progression in relapsing MS, but no efficient treatment exists for progressive MS. The aim of this research was to investigate the prevalence of adenosine A2A receptors and activated microglia in progressive MS by using in vivo positron emission tomography (PET) imaging and [11C]TMSX and [11C](R)‐PK11195 radioligands. Magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI) was performed to evaluate structural brain damage. Non‐invasive input function methods were also developed for the analyses of [11C]TMSX PET data. Finally, histopathological correlates of [11C](R)‐PK11195 radioligand binding related to chronic MS lesions were investigated in post‐mortem samples of progressive MS brain using autoradiography and immunohistochemistry. [11C]TMSX binding to A2A receptors was increased in NAWM of secondary progressive MS (SPMS) patients when compared to healthy controls, and this correlated to more severe atrophy in MRI and white matter disintegration (reduced fractional anisotropy, FA) in DTI. The non‐invasive input function methods appeared as feasible options for brain [11C]TMSX images obviating arterial blood sampling. [11C](R)‐PK11195 uptake was increased in the NAWM of SPMS patients when compared to patients with relapsing MS and healthy controls. Higher [11C](R)‐PK11195 binding in NAWM and total perilesional area of T1 hypointense lesions was associated with more severe clinical disability, increased brain atrophy, higher lesion load and reduced FA in NAWM in the MS patients. In autoradiography, increased perilesional [11C](R)‐PK11195 uptake was associated with increased microglial activation identified using immunohistochemistry. In conclusion, brain [11C]TMSX PET imaging holds promise in the evaluation of diffuse neuroinflammation in progressive MS. Being a marker of microglial activation, [11C](R)‐ PK11195 PET imaging could possibly be used as a surrogate biomarker in the evaluation of the neuroinflammatory burden and clinical disease severity in progressive MS.

Repercussions of a sleep medicine outreach program

Despite the high prevalence of sleep disorders, many healthcare professionals and lay people have little knowledge of Sleep Medicine. Mindful of such a reality, in 2001 the Sleep Institute of the Associação Fundo de Incentivo à Psicofarmacologia launched a campaign to increase Sleep Medicine awareness. Media features, exhibitions, inserts, and classes were used to reach 2,000,000 people and 55,000 healthcare professionals during the period from 2001 to 2004. To evaluate this program, we compared data for polysomnography referrals to the Institute in 2000 and in 2004. A total of 8805 referrals were evaluated (2000: 2164; 2004: 6641). Over the 4 years of the program, the number of beds increased by 43%; more women were referred (31 vs 37%; P < 0.001), mainly with a diagnostic hypothesis of sleep-disorder breathing (SDB). SDB was the most frequent diagnostic hypothesis in 2000 and 2004. In 2004 there were fewer referrals without a diagnostic hypothesis (27 vs 21%; P < 0.001) and for controlling surgically treated SDB (2.3 vs 1.6%; P < 0.05), and an increase in the following diagnostic hypotheses: non-invasive treatment of SDB (8.3 vs 12.3%; P < 0.001) and insomnia (3.5 vs 6.5%; P < 0.001). Insomnia diagnostic hypothesis was better correlated with SDB on referral documents in 2004 and less with a diagnostic hypothesis of limb movement disturbance. The program helped increase polysomnography referrals, particularly among women. Healthcare professionals appear to have a more developed understanding of sleep disorders.

Methodological approaches to planar and volumetric scintigraphic imaging of small volume targets with high spatial resolution and sensitivity

Single-photon emission computed tomography (SPECT) is a non-invasive imaging technique, which provides information reporting the functional states of tissues. SPECT imaging has been used as a diagnostic tool in several human disorders and can be used in animal models of diseases for physiopathological, genomic and drug discovery studies. However, most of the experimental models used in research involve rodents, which are at least one order of magnitude smaller in linear dimensions than man. Consequently, images of targets obtained with conventional gamma-cameras and collimators have poor spatial resolution and statistical quality. We review the methodological approaches developed in recent years in order to obtain images of small targets with good spatial resolution and sensitivity. Multipinhole, coded mask- and slit-based collimators are presented as alternative approaches to improve image quality. In combination with appropriate decoding algorithms, these collimators permit a significant reduction of the time needed to register the projections used to make 3-D representations of the volumetric distribution of target’s radiotracers. Simultaneously, they can be used to minimize artifacts and blurring arising when single pinhole collimators are used. Representation images are presented, which illustrate the use of these collimators. We also comment on the use of coded masks to attain tomographic resolution with a single projection, as discussed by some investigators since their introduction to obtain near-field images. We conclude this review by showing that the use of appropriate hardware and software tools adapted to conventional gamma-cameras can be of great help in obtaining relevant functional information in experiments using small animals.

Thermal modelling of commercial lithium-ion batteries

The accelerating adoption of electrical technologies in vehicles over the recent years has led to an increase in the research on electrochemical energy storage systems, which are among the key elements in these technologies. The application of electrochemical energy storage systems for instance in hybrid electrical vehicles (HEVs) or hybrid mobile working machines allows tolerating high power peaks, leading to an opportunity to downsize the internal combustion engine and reduce fuel consumption, and therefore, CO2 and other emissions. Further, the application of electrochemical energy storage systems provides an option of kinetic and potential energy recuperation. Presently, the lithium-ion (Li-ion) battery is considered the most suitable electrochemical energy storage type in HEVs and hybrid mobile working machines. However, the intensive operating cycle produces high heat losses in the Li-ion battery, which increase its operating temperature. The Li-ion battery operation at high temperatures accelerates the ageing of the battery, and in the worst case, may lead to a thermal runaway and fire. Therefore, an appropriate Li-ion battery cooling system should be provided for the temperature control in applications such as HEVs and mobile working machines. In this doctoral dissertation, methods are presented to set up a thermal model of a single Li-ion cell and a more complex battery module, which can be used if full information about the battery chemistry is not available. In addition, a non-destructive method is developed for the cell thermal characterization, which allows to measure the thermal parameters at different states of charge and in different points of cell surface. The proposed models and the cell thermal characterization method have been verified by experimental measurements. The minimization of high thermal non-uniformity, which was detected in the pouch cell during its operation with a high C-rate current, was analysed by applying a simplified pouch cell 3D thermal model. In the analysis, heat pipes were incorporated into the pouch cell cooling system, and an optimization algorithm was generated for the estimation of the optimalplacement of heat pipes in the pouch cell cooling system. An analysis of the application of heat pipes to the pouch cell cooling system shows that heat pipes significantly decrease the temperature non-uniformity on the cell surface, and therefore, heat pipes were recommended for the enhancement of the pouch cell cooling system.

X-Ray analysis to assess mechanical damage in sweet corn seeds

The X-ray test is a precise, fast and non-destructive method to detect mechanical damage in seeds. In the present study, the efficiency of X-ray analysis in identifying the extent of mechanical damage in sweet corn seeds and its relationship with germination and vigor was evaluated. Hybrid 'SWB 551' (sh2) seeds with round (R) and flat (F) shapes were classified as large (L), medium (M1, M2 and M3) and small (S), using sieves with round and oblong screens. After artificial exposure to different levels of damage (0, 1, 3, 5 and 7 impacts), seeds were X-rayed (15 kV, 5 min) and submitted to germination (25 °C/5 days) and cold (10 °C/7 days) tests. Digital images of normal and abnormal seedlings and ungerminated seeds from germination and cold tests were jointly analyzed with the seed X-ray images. Results showed that damage affecting the embryonic axis resulted in abnormal seedlings or dead seeds in the germination and cold tests. The X-ray analysis is efficient for identifying mechanical damage in sweet corn seeds, allowing damage severity to be associated with losses in germination and vigor.