'Free' surfactant in gastric aspirates and bronchoalveolar lavage in children with and without reflux oesophagitis

Aim: Dipalmitoylphosphatidycholine (DPPC) is the characteristic and main constituent of surfactant. Adsorption of surfactant to epithelial surfaces may be important in the masking of receptors. The aims of the study were to (i) compare the quantity of free DPPC in the airways and gastric aspirates of children with gastroesophageal reflux disease (GORD) to those without and (ii) describe the association between free DPPC levels with airway cellular profile and capsaicin cough sensitivity. Methods: Children aged <14 years were defined as 'coughers' if a history of cough in association with their GORD symptoms was elicited before gastric aspirates and nonbronchoscopic bronchoalveolar lavage (BAL) were obtained during elective flexible upper gastrointestinal endoscopy. GORD was defined as histological presence of reflux oesophagitis. Spirometry and capsaicin cough-sensitivity test was carried out in children aged >6 years before the endoscopy. Results: Median age of the 68 children was 9 years (interquartile range (IQR) 7.2). Median DPPC level in BAL of children with cough (72.7 μg/mL) was similar to noncoughers (88.5). There was also no significant difference in DPPC levels in both BAL and gastric aspirates of children classified according to presence of GORD. There was no correlation between DPPC levels and cellular counts or capsaicin cough-sensitivity outcome measures. Conclusion: We conclude that free DPPC levels in the airways and gastric aspirate is not influenced by presence of cough or GORD defined by histological presence of reflux oesophagitis. Whether quantification of adsorbed surfactant differs in these groups remain unknown. Free DPPC is unlikely to have a role in masking of airway receptors. © 2006 Royal Australasian College of Physicians.

Genetic studies of disorders of calcium crystal deposition

In summary, although many factors are likely to be involved in regulating calcification and ossification processes, studies of the causation of articular chondrocalcinosis and disorders of spinal ossification, such as DISH and OPLL, implicate control over inorganic pyrophosphate levels as being one of the most important factors in their aetiopathogenesis. The findings of these studies may prove relevant to other rheumatic diseases in which ectopic ossification occurs, such as AS.

Study of tracheal collapsibility, compliance and stress by considering its asymmetric geometry

The shape of tracheal cartilage has been widely treated as symmetric in analytical and numerical models. However, according to both histological images and in vivo medical image, tracheal cartilage is of highly asymmetric shape. Taking the cartilage as symmetric structure will induce bias in calculation of the collapse behavior, as well as compliance and muscular stress. However, this has been rarely discussed. In this paper, tracheal collapse is represented by considering its asymmetric shape. For comparison, the symmetric shape, which is reconstructed by half of the cartilage, is also presented. A comparison of cross-sectional area, compliance of airway and stress in the muscular membrane, determined by asymmetric shape and symmetric shape is made. The result indicates that the symmetric assumption brings a small error, around 5% in predicting the cross-sectional area under loading conditions. The relative error of compliance is more than 10%. Particularly when the pressure is close to zero, the error could be more than 50%. The model considering the symmetric shape results in a significant difference in predicting stress in muscular membrane by either under- or over-estimating it. In conclusion, tracheal cartilage should not be treated as a symmetric structure. The results obtained in this study are helpful in evaluating the error induced by the assumption in geometry.

Groucho homologue Grg5 interacts with the transcription factor Runx2-Cbfa1 and modulates its activity during postnatal growth in mice

Runx2-Cbfal, a Runt transcription factor, plays important roles during skeletal development. It is required for differentiation and function of osteoblasts. In its absence, chondrocyte hypertrophy is severely impaired and there is no vascularization of cartilage templates during skeletal development. These tissue-specific functions of Runx2 are likely to be dependent on its interaction with other proteins. We have therefore searched for proteins that may modulate the activity of Runx2. The yeast two-hybrid system was used to identify a groucho homologue, Grg5, as a Runx2-interacting protein. Grg5 enhances Runx2 activity in a cell culture-based assay and by analyses of postnatal growth in mice we demonstrate that Grg5 and Runx2 interact genetically. We also show that Runx2 haploinsufficiency in the absence of Grg5 results in a more severe delay in ossification of cranial sutures and fontanels than occurs with Runx2 haploinsufficiency on a wild-type background. Finally, we find shortening of the proliferative and hypertrophic zones, and expansion of the resting zone in the growth plates of Runx2(+/-)Grg5(-/-) mice that are associated with reduced Ihh expression and Indian hedgehog (Ihh) signaling. We therefore conclude that Grg5 enhances Runx2 activity in vivo.

Timing of weaning and processing: effects on liveweight changes of weaner cattle

To reduce the number of musters and handling costs, calves in extensive cattle herds in northern Australia are processed (vaccinated, ear-marked, de-horned, branded and males castrated) shortly after they are weaned. As stress has adverse effects on health and growth, and weaning is a stressful time for calves, this experiment asked if calf health, welfare and performance were improved when calves had a period with their mothers post-processing, before they were weaned.

Ruumiinkuvia! : Suomalainen performanssi- ja kehotaide 1980- ja1990-luvulla psykoanalyysin valossa

My PhD-thesis Body Images! Psychoanalytical Analysis of Finnish Performance and Body Art in the 1980s and 1990s considers Finnish performance and body art performed mainly by visual artists. In Part I, I chart the historical construction of performance art and its extension since the beginning of the 21st century. There are several wievs of the historical background of performance art. I introduce three different genealogies of performance art. One is Rose-Lee Goldberg s view. She connects performance art with the European avant-garde already at the beginning of the 20th century from futurists and dadaists to Russian avant-garde and the Bauhaus. I prefer to present performance art as contemporary art, which began to take shape in connection with visual arts in the 1950s and 1960s. The focus on the body is apparent in nearly all performance art. Nevertheless, throug the concept of body art I want to empasize the artist s body as the place of art. Body art (as part of performance art) functions as thematic and interpretive concept, which allows me to focus on performances where the questions of body image, narcissism, desire, language and pleasure are incorporated in particular intensive ways. In Part II, I explore the arrival of performance art in Finnish visual arts in the 1980s. I study the new generation s relation to earlier Finnish happenings (1960s) and performative actions in 1970 s. I briefly introduce performance groups of the 1980s art scene and consider their reception in media. The main focus is on the group Jack Helen Brut, in which I see many similarities to the so- called Theatre of Images. The goal of this part II is to provide historical context for the performance analysis that follows. In Part III, I develop the concept of body image which is my main theoretical term. The concept of body image is used according to Lacanian psychoanalytical theory, especially his considerations of mirror stages. My first mapping of body image, which I call imaginary body image, is based on Lacan s famous mirror stage article (1949). According to my reading, body image is narcistic and aggressive. The important concepts here are ego, imaginary, méconnaisance and alienation. In 1953 Lacan began to develop different version on mirror stage, in which he emphasized the primacy of symbolic dimension. It is not image, but language which constructs the foundations of body image. Central concepts in this chater are Other as language, ego-ideal, demand and desire. In the last chapter I connect the third version of the mirror stage to concepts of gaze, phantasy, real, jouissance and object a. In previous chapters I had considered body image in relation to ego. Now I explore it in relation to subject. In my reading the body image is fragile phenomen, which oscillates between yearning for coherence and phantasies of fragmented images. Part IV of the thesis begins with an introduction to the central concepts and debates in performace studies over the last few decades. Important concepts are presence, performativity and theatricality. The main substance of my thesis, however, is the performance analysis, which focuses on works by three Finnish artists and one Finnish group. The first analysis concerns the performance (1992) of Kimmo Schroderus. I discuss the relationship between narcissism and body art and the changes in demands projected on body images of men in recent decades in a Euro-American context. I also explore this performance in relation to the myth of Narcissus, which I reinterpret through Narcissus s aggression against his own body. The group Homo S is the main subject of the next analysis. I discuss the relationship between feminist art and performance art, especially in the United States in the 1960s and 1970s. Homo S is different from this early performance art because of its anarchism, humor and rejection of all ideals. Homo S characterizes its performance Body Body (1983) as liberating vulgar feminism . Sociality and performance of erotic relations between women are central in Body Body. Pia Lindman s performances are the subjects of my third analysis. I study three of her performances: Olen muoto (1993), 17 and in love (1994) and Arranged views (1995). I interpret these performances as efforts to disperse the imaginary and symbolic structures of the body image. She constructs the peculiar object a and phantasy space of her own. In the last analysis I move from questions of image and gaze to a study of language, sound and jouissance. I discuss at a general level the performance of orality and helplesness (Hilflosigkeit) in body art. The central elements in Pentti Otto Koskinen s performances are the ear, listening and receptive gestures and postions. Perseveraatio (1998) can be understood representing as submission to the super-ego s power, which compels one to enjoy. I examine particularly closely the performance Maissi on hyvää ei missään nimessä maissia (1995), which I interpret as the return of a baby s body image to the liminal site of choice: language or jouissance?

Association of hearing impairment and subsequent driving mobility in older adults

- Purpose of the study Hearing impairment (HI) is associated with driving safety (e.g., increased crashes and poor on-road driving performance). However, little is known about HI and driving mobility. This study examined the longitudinal association of audiometric hearing with older adults’ driving mobility over three years. - Design and Methods Secondary data analyses were conducted of 500 individuals (63-90 years) from the Staying Keen in Later Life (SKILL) study. Hearing (pure tone average of 0.5, 1, and 2 kHz) was assessed in the better hearing ear and categorized into normal hearing <25 dB HL; mild HI 26-40 dB HL; or moderate and greater HI>41 dB HL. The Useful Field of View Test (UFOV) was used to estimate the risk for adverse driving events. MANCOVA compared driving mobility between HI levels across time, adjusting for age, sex, race, hypertension, and stroke. Adjusting for these same covariates, Cox regression analyses examined incidence of driving cessation by HI across three years. - Results Individuals with moderate or greater HI performed poorly on the UFOV, indicating increased risk for adverse driving events (p<.001). No significant differences were found among older adults with varying levels of HI for driving mobility (ps>.05), including driving cessation rates (p=.38), across time. - Implications Although prior research indicates older adults with HI may be at higher risk for crashes, they may not modify driving over time. Further exploration of this issue is required to optimize efforts to improve driving safety and mobility among older adults.

Koko talo soi : Klemetti-Opisto suomalaisen musiikkikulttuurin kehittäjänä 1953-1968

This study aims to examine the operations and significance of the Klemetti Institute (Klemetti-Opisto) as a developer of Finnish music culture from 1953 to 1968 during the term of office of the Institute s founder and first director, Arvo Vainio. The Klemetti Institute was originally established as a choir institute, but soon expanded to offer a wide range of music courses. In addition to providing courses for choir leaders and singers, the Institute began its orchestral activities as early as the mid-1950s. Other courses included ear training seminars as well as courses for young people s music instructors and in playing the kantele (a Finnish string instrument) and solo singing. More than 20 types of courses were offered over the 16-year period. The Klemetti Institute s courses were incorporated into the folk high school courses offered by the Orivesi Institute (Oriveden Opisto) and were organised during the summer months of June and July. In addition to funding based on the Folk High School Act, financial assistance was obtained from various foundations and funds, such as the Wihuri Foundation. This study is linked to the context of historical research. I examine the Klemetti Institute s operations chronologically, classifying instruction into different course types, and analyse concert activities primarily in the section on the Institute s student union. The source material includes the Klemetti Institute archives, which consist of Arvo Vainio s correspondence, student applications, register books and cards, journals and student lists, course albums and nearly all issues of the Klemettiläinen bulletin. In addition, I have used focused interviews and essays to obtain extensive data from students and teachers. I concentrate on primary school teachers, who accounted for the majority of course participants. A total of more than 2,300 people participated in the courses, nearly half of whom took courses during at least two summers. Primary school teachers accounted for 50% to 70% of the participants in most courses and constituted an even larger share of participants in some courses, such as the music instructor course. The Klemetti Institute contributed to the expansion throughout Finland of a new ideal for choral tone. This involved delicate singing which strives for tonal purity and expressiveness. Chamber choirs had been virtually unheard of in Finland, but the Klemetti Institute Chamber Choir popularised them. Chamber choirs are characterised by an extensive singing repertoire ranging from the Middle Ages to the present. As the name suggests, chamber choirs were originally rather small mixed choirs. Delicate singing meant the avoidance of extensive vibrato techniques and strong, heavy forte sounds, which had previously been typical of Finnish choirs. Those opposing and shunning this new manner of singing called it ghost singing . The Klemetti Institute s teachers included Finland s most prominent pedagogues and artists. As the focused essays, or reminiscences as I call them, show, their significance for the students was central. I examine extensively the Klemetti Institute s enthusiastic atmosphere, which during the early years was characterised by what some writers described as a hunger for music . In addition to distributing a new tonal ideal and choir repertoire, the Klemetti Institute also distributed new methods of music education, thus affecting the music teaching of Finnish primary schools, in particular. The Orff approach, which included various instruments, became well known, although some of Orff s ideas, such as improvisation and physical exercise, were initially unfamiliar. More important than the Orff approach was the in-depth teaching at the Klemetti Institute of the Hungarian ear training method known as the Kodály method. Many course participants were among those launching specialist music classes in schools, and the method became the foundation for music teaching in many such schools. The Klemetti Institute was also a pioneer in organising orchestra camps for young people. The Klemetti Institute promoted Finnish music culture and played an important role in the continuing music education of primary school teachers. Keywords: adult education, Grundtvigian philosophy, popular enlightenment, Klemetti Institute, Kodály method, choir singing, choir conducting, music history, music education, music culture, music camp, Orff approach, Orff-Schulwerk, Orivesi Institute, instrument teaching, free popular education, communality, solo singing, voice production

Muusikon mentaaliharjoittelu : Konsertoivan ja opettavan pianistin mentaaliharjoittelu

This research explores the foci, methods and processes of mental training by pianists who are active as performers and teachers. The research is based on the concept of mental training as a solely mental mode of practising. Musician s mental training takes place without an instrument or the physical act of playing. The research seeks answers to questions: 1) What are the foci of a pianist s mental training? 2) How does a pianist carry out the mental training? 3) What does mental training in music entail as a process? The research approach is qualitative, and the materials were gathered from thematic interviews. The aim of practising is always an improved result both in the act of playing and the performance. Mental training by a pianist is collaboration between technical, auditory, visual, kinaesthetic and affective factors. Also interpretation, memory and overcoming stage fright are needed. Technical, cognitive and performance skills are involved. According to the results of this research, mental training is a goal-oriented activity which can have an impact on all of these factors. Without a musical inner ear and its functionality, true musicianship cannot exist. One particular result of this research is the conceptualisation of opening up the inner ear. Auditory exercises and internally playing mental images are essential elements of the mental practice of a musician. Visual images, such as a picture of music notation or a performance event, are the point of focus for musicians who find visual images to be the easiest to realise. When developing technical skills by using mental training, it is important to focus on the technically most difficult sections. It is also necessary to focus on the holistic experiencing of the performance situation. By building on positive energies and strengths, the so-called psyching up may be the most important element in mental training. Based on the results of this research, a synthesis is outlined of the music event as an activity process, built on representations and schemes. Mental training aims at the most ideal possible act of playing and the creation of a musical event; these are achieved by focussing on various mental images produced by the different senses, together with concrete practising. Mental training in sports and in music share common factors. Both modes of practising, mental as well as physical, involve three important elements: planning, realisation and evaluation of the practice. In music, however, the goal is an artistic end result which does not often apply to an athletic event. Keywords: Mental training in music, auditory imagining, visualisation, kinaesthetic-mental experience, mastery of the psyche

Design and characterisation of scaffolds for osteochondral regeneration

Treatment of joint diseases such as osteoarthritis is difficult and requires extensive developments for adequate solutions to emerge. Continued innovation in projects explored in this thesis may be beneficial to understanding the requirements of the joint environment. This may then lead to constructs that perform desirably from both mechanical and biological standpoints, resulting in complete, tissue-engineered osteochondral solutions. This thesis investigated specific scaffold designs for bone and osteochondral tissue engineering, as well as the formation of complex criteria on which cartilage hydrogel scaffolds may be assessed. The combination of hydrogels and ceramics were found to maintain chondrogenesis, while the concentration of photoinitiators in photocrosslinkable hydrogel systems may be optimised to maximise mechanical properties and cell viability. Finally, viscoelasticity of hydrogel blends was assessed using oscillatory motion, demonstrating the property is tailorable.

Expression of cytochrome P450 enzymes and metabolism of timolol in human ocular tissue

Glaucoma is a group of progressive optic neuropathies causing irreversible blindness if not diagnosed and treated in the early state of progression. Disease is often, but not always, associated with increased intraocular pressure (IOP), which is also the most important risk factor for glaucoma. Ophthlamic timolol preparations have been used for decades to lower increased intraocular pressure (IOP). Timolol is locally well tolerated but may cause e.g. cardiovascular and pulmonary adverse effects due to systemic absorption. It has been reported that approximately 80% of a topically administered eye drop is systemically absorbed. However, only limited information is available on timolol metabolism in the liver or especially in the human eye. The aim of this work was to investigate metabolism of timolol in human liver and human ocular tissues. The expression of drug metabolizing cytochrome P450 (CYP) enzymes in the human ciliary epithelial cells was studied. The metabolism of timolol and the interaction potential of timolol with other commercially available medicines were investigated in vitro using different liver preparations. The absorption of timolol to the aqueous humor from two commercially available products: 0.1% eye gel and 0.5% eye drops and the presence of timolol metabolites in the aqueous humor were investigated in a clinical trial. Timolol was confirmed to be metabolized mainly by CYP2D6 as previously suggested. Potent CYP2D6 inhibitors especially fluoxetine, paroxetine and quinidine inhibited the metabolism of timolol. The inhibition may be of clinical significance in patients using ophthalmic timolol products. CYP1A1 and CYP1B1 mRNAs were expressed in the human ciliary epithelial cells. CYP1B1 was also expressed at protein level and the expression was strongly induced by a known potent CYP1B1 inducer 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The CYP1B1 induction is suggested to be mediated by aryl hydrocarbon receptor (AHR). Low levels of CYP2D6 mRNA splice variants were expressed in the human ciliary epithelial cells and very low levels of timolol metabolites were detected in the human aqueous humor. It seems that negligible amount of CYP2D6 protein is expressed in the human ocular tissues. Timolol 0.1% eye gel leads to aqueous humor concentration high enough to achieve therapeutic effect. Inter-individual variation in concentrations is low and intraocular as well as systemic safety can be increased when using this product with lower timolol concentration instead of timolol 0.5% eye drops.

Determination of management units for grey mackerel fisheries in northern Australia.

The requirement for Queensland, Northern Territory and Western Australian jurisdictions to ensure sustainable harvest of fish resources and their optimal use relies on robust information on the resource status. For grey mackerel (Scomberomorus semifasciatus) fisheries, each of these jurisdictions has their own management regime in their corresponding waters. The lack of information on stock structure of grey mackerel, however, means that the appropriate spatial scale of management is not known. As well, fishers require assurance of future sustainability to encourage investment and long-term involvement in a fishery that supplies lucrative overseas markets. These management and fisher-unfriendly circumstances must be viewed in the context of recent 3-fold increases in catches of grey mackerel along the Queensland east coast, combined with significant and increasing catches in other parts of the species' northern Australian range. Establishing the stock structure of grey mackerel would also immensely improve the relevance of resource assessments for fishery management of grey mackerel across northern Australia. This highlighted the urgent need for stock structure information for this species. The impetus for this project came from the strategic recommendations of the FRDC review by Ward and Rogers (2003), "Northern mackerel (Scombridae: Scomberomorus): current and future research needs" (Project No. 2002/096), which promoted the urgency for information on the stock structure of grey mackerel. In following these recommendations this project adopted a multi-technique and phased sampling approach as carried out by Buckworth et al (2007), who examined the stock structure of Spanish mackerel, Scomberomorus commerson, across northern Australia. The project objectives were to determine the stock structure of grey mackerel across their northern Australian range, and use this information to define management units and their appropriate spatial scales. We used multiple techniques concurrently to determine the stock structure of grey mackerel. These techniques were: genetic analyses (mitochondrial DNA and microsatellite DNA), otolith (ear bones) isotope ratios, parasite abundances, and growth parameters. The advantage of using this type of multi-technique approach was that each of the different methods is informative about the fish’s life history at different spatial and temporal scales. Genetics can inform about the evolutionary patterns as well as rates of mixing of fish from adjacent areas, while parasites and otolith microchemistry are directly influenced by the environment and so will inform about the patterns of movement during the fishes lifetime. Growth patterns are influenced by both genetic and environmental factors. Due to these differences the use of these techniques concurrently increases the likelihood of detecting different stocks where they exist. We adopted a phased sampling approach whereby sampling was carried out at broad spatial scales in the first year: east coast, eastern Gulf of Carpentaria (GoC), western GoC, and the NW Northern Territory (NW NT). By comparing the fish samples from each of these locations, and using each of the techniques, we tested the null hypothesis that grey mackerel were comprised of a single homogeneous population across northern Australia. Having rejected the null hypothesis we re-sampled the 1st year locations to test for temporal stability in stock structure, and to assess stock structure at finer spatial scales. This included increased spatial coverage on the east coast, the GoC, and WA. From genetic approaches we determined that there at least four genetic stocks of grey mackerel across northern Australia: WA, NW NT (Timor/Arafura), the GoC and the east Grey mackerel management units in northern Australia ix coast. All markers revealed concordant patterns showing WA and NW NT to be clearly divergent stocks. The mtDNA D-loop fragment appeared to have more power to resolve stock boundaries because it was able to show that the GoC and east coast QLD stocks were genetically differentiated. Patterns of stock structure on a finer scale, or where stock boundaries are located, were less clear. From otolith stable isotope analyses four major groups of S. semifasciatus were identified: WA, NT/GoC, northern east coast and central east coast. Differences in the isotopic composition of whole otoliths indicate that these groups must have spent their life history in different locations. The magnitude of the difference between the groups suggests a prolonged separation period at least equal to the fish’s life span. The parasite abundance analyses, although did not include samples from WA, suggest the existence of at least four stocks of grey mackerel in northern Australia: NW NT, the GoC, northern east coast and central east coast. Grey mackerel parasite fauna on the east coast suggests a separation somewhere between Townsville and Mackay. The NW NT region also appears to comprise a separate stock while within the GoC there exists a high degree of variability in parasite faunas among the regions sampled. This may be due to 1. natural variation within the GoC and there is one grey mackerel stock, or 2. the existence of multiple localised adult sub-stocks (metapopulations) within the GoC. Growth parameter comparisons were only possible from four major locations and identified the NW NT, the GoC, and the east coast as having different population growth characteristics. Through the use of multiple techniques, and by integrating the results from each, we were able to determine that there exist at least five stocks of grey mackerel across northern Australia, with some likelihood of additional stock structuring within the GoC. The major management units determined from this study therefore were Western Australia, NW Northern Territory (Timor/Arafura), the Gulf of Carpentaria, northern east Queensland coast and central east Queensland coast. The management implications of these results indicate the possible need for management of grey mackerel fisheries in Australia to be carried out on regional scales finer than are currently in place. In some regions the spatial scales of management might continue as is currently (e.g. WA), while in other regions, such as the GoC and the east coast, managers should at least monitor fisheries on a more local scale dictated by fishing effort and assess accordingly. Stock assessments should also consider the stock divisions identified, particularly on the east coast and for the GoC, and use life history parameters particular to each stock. We also emphasise that where we have not identified different stocks does not preclude the possibility of the occurrence of further stock division. Further, this study did not, nor did it set out to, assess the status of each of the stocks identified. This we identify as a high priority action for research and development of grey mackerel fisheries, as well as a management strategy evaluation that incorporates the conclusions of this work. Until such time that these priorities are addressed, management of grey mackerel fisheries should be cognisant of these uncertainties, particularly for the GoC and the Queensland east coast.

Genetic effects and genetic relationships among shrunken (sh2) sweet corn lines and F1 hybrids

The objectives of this study were to quantify the components of genetic variance and the genetic effects, and to examine the genetic relationship of inbred lines extracted from various shrunken2(sh2) breeding populations. Ten diverse inbred lines developed from genetic background, were crossed in half diallel. Parents and their F1 hybrids were evaluated at three environments. The parents were genotyped using 20 polymorphic simple sequence repeats (SSR). Agronomic and quality traits were analysed by a mixed linear model according to additive-dominance genetic model. Genetic effects were estimated using an adjusted unbiased prediction method. Additive variance was more important than dominance variance in the expression of traits related to ear aspects (husk ratio and percentage of ear filled) and eating quality (flavour and total soluble solids). For agronomic traits, however, dominance variance was more important than additive variance. The additive genetic correlation between flavour and tenderness was strong (r = 0.84, P <0.01). Flavour, tenderness and kernel colour additive genetic effects were not correlated with yield related traits. Genetic distance (GD), estimated from SSR profiles on the basis of Jaccard's similarity coefficient varied from 0.10 to 0.77 with an average of 0.56. Cluster analysis classified parents according to their pedigree relationships. In most studied traits, F1 performance was not associated with GD.

Combining ability, genetic diversity and heterosis in relation to F1 performance of tropically adapted shrunken (sh2) sweet corn lines

With 6 tables Abstract The objectives of this study were to evaluate the importance of heterosis for agronomic and quality traits in shrunken (sh2) sweet corn, assess the usefulness of combining ability to predict the value of parents and their crosses for further genetic improvement and examine whether genetic divergence can predict heterosis or F1 performance. Ten genetically diverse shrunken (sh2) sweet corn inbred lines were used to generate 45 F1s. F1s and parents were evaluated for agronomic and quality traits across environments. Heterosis was more important for yield-related traits than it was for ear aspects and eating quality. Heterosis for most traits was mostly dependent on dominance genetic effects of parental lines. Parents and F1per se performance were highly correlated with general combining ability effects and mid-parent values, respectively, for most traits. Hybrid performance for flavour and plant height was significantly but weakly related to simple sequence repeat (SSR)-based genetic distance (GD). Phenotypic distance (PD), estimated from phenotypic traits was correlated with heterosis for total soluble solids, ear length and flavour. © 2012 State of Queensland.

Investigation of the effects of extracellular osmotic pressure on morphology and mechanical 1 properties of individual chondrocyte

It has been demonstrated that most cells of the body respond to osmotic pressure in a systematic manner. The disruption of the collagen network in the early stages of osteoarthritis causes an increase in water content of cartilage which leads to a reduction of pericellular osmolality in chondrocytes distributed within the extracellular environment. It is therefore arguable that an insight into the mechanical properties of chondrocytes under varying osmotic pressure would provide a better understanding of chondrocyte mechanotransduction and potentially contribute to knowledge on cartilage degeneration. In this present study, the chondrocyte cells were exposed to solutions with different osmolality. Changes in their dimensions and mechanical properties were measured over time. Atomic Force Microscopy (AFM) was used to apply load at various strain-rates and the force-time curves were logged. The thin-layer elastic model was used to extract the elastic stiffness of chondrocytes at different strain-rates and at different solution osmolality. In addition, the porohyperelastic (PHE) model was used to investigate the strain-rate dependent responses under the loading and osmotic pressure conditions. The results revealed that the hypo-osmotic external environment increased chondrocyte dimensions and reduced Young’s modulus of the cells at all strain-rates tested. In contrast, the hyper-osmotic external environment reduced dimensions and increased Young’s modulus. Moreover, by using the PHE model coupled with inverse FEA simulation, we established that the hydraulic permeability of chondrocytes increased with decreasing extracellular osmolality which is consistent with previous work in the literature. This could be due to a higher intracellular fluid volume fraction with lower osmolality.