Transcriptional insights on the regenerative mechanics of axotomized neurons in vitro

Axotomized neurons have the innate ability to undergo regenerative sprouting but this is often impeded by the inhibitory central nervous system environment. To gain mechanistic insights into the key molecular determinates that specifically underlie neuronal regeneration at a transcriptomic level, we have undertaken a DNA microarray study on mature cortical neuronal clusters maintained in vitro at 8, 15, 24 and 48 hrs following complete axonal severance. A total of 305 genes, each with a minimum fold change of &plusmn;1.5 for at least one out of the four time points and which achieved statistical significance (one-way ANOVA, P < 0.05), were identified by DAVID and classified into 14 different functional clusters according to Gene Ontology. From our data, we conclude that post-injury regenerative sprouting is an intricate process that requires two distinct pathways. Firstly, it involves restructuring of the neurite cytoskeleton, determined by compound actin and microtubule dynamics, protein trafficking and concomitant modulation of both guidance cues and neurotrophic factors. Secondly, it elicits a cell survival response whereby genes are regulated to protect against oxidative stress, inflammation and cellular ion imbalance. Our data reveal that neurons have the capability to fight insults by elevating biological antioxidants, regulating secondary messengers, suppressing apoptotic genes, controlling ion-associated processes and by expressing cell cycle proteins that, in the context of neuronal injury, could potentially have functions outside their normal role in cell division. Overall, vigilant control of cell survival responses against pernicious secondary processes is vital to avoid cell death and ensure successful neurite regeneration.

Association of different forms of bullying victimisation with adolescents' psychological distress and reduced emotional wellbeing

OBJECTIVE: The frequency and emotional response to bullying victimisation are known to be associated with adolescent mental ill health. A potentially important under-investigated factor is the form of bullying. Four common forms of bullying behaviours are name-calling, physical threats or harm, rumour spreading and social exclusion. To more comprehensively understand bullying victimisation in adolescence, we examined the association of all three factors (frequency, emotional response, form) to psychological distress and emotional wellbeing. METHOD: A stratified, random sample of adolescents (n&thinsp;=&thinsp;10, 273; mean age&thinsp;=&thinsp;14.33&thinsp;years, standard deviation&thinsp;=&thinsp;1.68&thinsp;years) completed validated measures of bullying victimisation (Gatehouse Bullying Questionnaire), psychological distress (K10) and emotional wellbeing (Mental Health Inventory) in classroom time. Associations between the form of bullying victimisation and mental health outcomes were examined. RESULTS: Adolescents reported a high prevalence of all four forms of bullying: teased or called names (30.6%), rumour spreading (17.9%), social exclusion (14.3%) and physical threats or harm (10.7%). Victimisation was independently associated with significantly higher levels of psychological distress and reduced levels of emotional wellbeing for all forms of bullying. In particular, social exclusion had a strong association with mental ill health. Adolescents who experienced frequent bullying that was upsetting reported higher psychological distress and reduced emotional wellbeing. CONCLUSION: Different forms of bullying victimisation were independently associated with psychological distress and reduced emotional wellbeing. In particular, frequent and upsetting social exclusion requires a targeted and measured response by school communities and health practitioners.

Clinical placement and rurality of career commencement : a pilot study

This article reports on a project that aimed to discover whether rural placement can influence new graduates to take up rural positions, and what factors play a role in the decision-making. This pilot study reports the findings from a pre-survey of students (n = 110) who completed a questionnaire at the end of their rural placement in the Greater Green Triangle region, Australia. Findings are compared with matched questionnaire responses for students who subsequently completed a post-survey after graduation and who commenced work (n = 28). Rural placement appears to be associated with commencing rural practice after graduation. More graduates with an urban home address commenced rural practice than graduates with a rural home address who started their careers in the city. Longer placements may sway those with a city background to start work in a rural area.

Lichen flora of the Mount Donna Buang Scenic Reserve, Victoria

This report investigated the lichen flora of the Mt Donna Buang Scenic Reserve in Victoria, There were several aims: to describe the lichens of the region, to produce a pictorial key enabling field identification and to determine any distribution patterns. A floristic survey covering approximately 50 square km was undertaken to determine lichen diversity of the region generally. Lichens were sampled along roads, tracks, walking trails and in sections of bush, taking into account forest type and, particularly, areas that were lichen rich. Seventy-five lichen species in 43 genera and 27 families were identified and described from the region. An unknown, species H, also was described. Of the 76 lichen species, 22 were crastose and the remainder macrolichens. The best represented families were: Cladoniaceae (8 species), Hypogymniaceae (6), Lobariaceae (7), Lecideaceae (6), Pannariaceae (6) and Parmeliaccae (6). This study described 12 species (17%) which previously were not known for Victoria and which are a first record for the state. These include: Cladonia sarmentosa (J.D. Hook & Taylor) Dodge, Graphis librata Knight, Parmelinopsis neodamaziana (Elix & Johnston) Elix & Hale, Pertusaria novaezelandiae Szatala, Placopsis pardlina f. microphylla Lamb, Porina leptalea AX. Sm., Pseudocyphellaria ardesiaca Galloway, Trapeliopsis congregant (Zahlbr.) Brako, Menegazzia myriotrema (Mull. Arg.) P. James, Bunodophoron scrobiculatum (Church. Bab,) Wedin, Parmelia testacea Stirton and Menegazzia purpurascens S. Louwhoff sp. nov.. The last eight species are new to the mainland and, apart from Menegazzia purpurascens, previously were known only from Tasmania. Five main elements of distribution were identified for the lichen flora of the Mt Donna Buang Scenic Reserve: cosmopolitan, austral/australasian, paleotropical, pantropical and western pacific. The majority of species (68%) had austral/australasian distributions, eleven (16%) were endemic to Australia and nine (13%) occurred only in Tasmania , Victoria and New Zealand. A pictorial, dichotomous key was constructed for the lichen flora of the Mt Donna Buang Scenic Reserve. Previously, keys to the lichen flora of Tasmanian rainforests were suggested as appropriate to similar areas in Victoria, however, the Victorian forests include a significant sclerophyll element The key presented is specific for the study site but is appropriate to similar regions in Victoria and has been tested in a number of these areas. The key was designed to be ‘user-friendly’ so that the experienced and inexperienced alike are able to use it. A more detailed investigation of the lichen flora of the Mt Donna Buang Scenic Reserve was carried out in order to determine distribution. A total of 50 quadrats, each 20m x 20m in size, were sampled. Within each, the dominant vegetation type was determined and individuals were identified and location noted. The cover abundance of each lichen species on each individual tree was estimated using a modified Braun-Blanquet scale. A total of 710 trees, representing 13 different species, were examined. Nothofagus cunninghamii (Hook.) Oerst, Eucalyptus regnans R Mull., Acacia dealbata Link, A. melanoxylon R. Br., Hedycarya angustifolia A. Cunn. and Atherosperma moschatum Labill. were the six most common tree species encountered at the study site. Nothofagus cunninghamii supported the greatest lichen diversity (39 species), although most species occurred on less than 10% of the trees. The majority of lichens occurring on N. cunninghamii A. melanoxylon, A. dealbata and H. angustifolia were foliose or crustose, those on Ł. regnans fruticose and foliose and those on A moschatum crustose. Bunodophoron australe was the only lichen species at the study site to occur on one host, Nothofagus cunninghamiL Many occurred on a number of different hosts, but were most common on one particular tree species. The distribution of lichens at the study site was analysed with a rnultivariate statistical package (PATN) which dealt with ‘pattern analysis’. The program ‘SSH’ in PATN which uses the Bray-Curtis ordination technique, was used to create scatterplots displaying the degree of dissimilarity between quadrats in terms of presence/absence of lichen species. The program ‘TWAY’ in PATN was used to construct a two way table to display which lichen species occurred in each vegetation type. The pattern analysis revealed that the lichens of the Mt Donna Buang Scenic Reserve were not restricted to any particular forest type, but particular lichens, or groups of lichens, tended to predominate in certain vegetation communities. This concurs with work done by others in Tasmanian forests. Quadrats which were situated in cool temperate rainforest were grouped more closely with each other than with quadrats in other vegetation types. These also supported the greatest number of lichen species. This was not surprising since N. cunninghamii the dominant tree species in cool temperate rainforest, supported the greatest lichen diversity.

Microwave dielectric properties of PTFE/rutile nanocomposites

The effects of nano-size rutile filler on the microwave dielectric properties of PTFE composites were investigated and the results were compared with that of micron size rutile filled composites. Nano-size rutile powder was prepared through sol–gel route and the filled PTFE composites were fabricated through SMECH process. Different characterization techniques such as powder X-ray diffraction, SEM, BET, TEM and TG/DSC were employed to analyze the nature of ceramic filler. The dielectric properties of filled composites were evaluated at microwave frequency region using waveguide cavity perturbation technique. Different theoretical models have been employed to predict the variation of dielectric constant with respect to filler loading. The moisture absorption characteristics of nano-rutile filled PTFE composites were measured as per IPC-TM-650 2.6.2 standards. Composites show high dielectric constant at X-band frequency region with relatively high loss tangent compared to micron size counterpart.

Preparation, characterization and dielectric properties of temperature stable SrTiO3/PEEK composites for microwave substrate applications

Poly(ether ether ketone) (PEEK) is a potential candidate for electronic applications due to its low permittivity, low loss, high melting point, better chemical resistance, excellent insulating properties and easy processibility. Present paper discusses the preparation and characterization of SrTiO3 filled PEEK composite for microwave substrate applications. The dielectric constant, dielectric loss and temperature variation of dielectric constant of the composites have been studied up to 1 MHz using an Impedance Analyzer. Different theoretical approaches have been employed to predict the effective permittivity of composite systems and the results are compared with that of the experimental data. The crystallinity of the bulk composite is studied by X-ray diffraction studies. Scanning electron microscopic technique has been employed to study the dispersion of the particulate filler in PEEK matrix. Vickers hardness of pure and filled PEEK composite has been measured using Microhardness Tester. The effect of particle size on the dielectric as well as mechanical properties of SrTiO3/PEEK composite system is also studied by incorporating micronsize and nanosize fillers. Present study shows that a temperature stable composite can be realized by judiciously selecting appropriate filler concentration in the PEEK matrix.

Isolation of a gene preferentially expressed in mature anthers of rice (Oryza sativa L.)

Using monoclonal antibodies raised against pollen-specific proteins, we have isolated a cDNA clone, designatedOry-Cl from a rice anther cDNA expression library. A transcript corresponding to theOry-Cl gene showed preferential expression in anthers. This transcript was not detected in any vegetative tissues analysed. RNA gel blot analysis of different developmental stages of anthers showed that theOry-Cl gene is expressed at later stages of pollen development. In situ hybridisation showed that theOry-Cl transcript is only present in mature pollen.

Antibodies to pollen exine

A polyclonal antiserum and monoclonal antibodies have been prepared to purified pollen exines of Calocedrus decurrens Florin. The location of the antigen is in the exine, as shown by light-and electron-microscopic immunocytochemistry. The greatest reduction in antibody binding follows treatment of the exine with chemicals known to alter sporopollenin. These results provide evidence that sporopollenin is antigenic. Exines of ten species of gymnosperms and angiosperms also bound the polyclonal antiserum, indicating similarity of sporopollenin structure.

Placing space/time through photography’s old and new technologies

The discovery that an impressively strong 3-dimensional effect in a 2-dimensional photographic representation&nbsp;of natural outdoor scenes occurs when a single camera&nbsp;is directed around one point in the scene, thus drawing&nbsp;into relief the subject of attention and blurring the&nbsp;surrounding space, has important implications for&nbsp;understanding basic processes in 3-dimensional vision.&nbsp;For the development of new ways for generating 3D&nbsp;effects in motion and static representations of scenes we&nbsp;might well learn from photography’s old technologies,&nbsp;as well as digital technologies of the static print, which&nbsp;have yet to release the full impact of their potential in&nbsp;the representation of motion and space.

Rickettsia

Rickettsial diseases are often undiagnosed because the treating doctor doesn’t consider it as part of the differential diagnosis, especially in Australia. A travel history is often helpful. For example, scrub typhus (Orientia tsutsugamushi) is only present in northern, tropical Australia; returning sick from a southern African game park may be due to African Tick Typhus (Rickettsia africae), following tick bites.

Measurement and analysis of pavement marking retroreflectivity

Retroreflective pavement markings enhance road safety by increasing visibility of roadway delineation for road users. In most countries, authorities responsible for road safety do not have performance intervention criteria and standards, and rely on fixed-time interval maintenance programs. This practice is undergoing change via the introduction of mobile retroreflectivity recording units. The focus of this study is to investigate the use of standard mobile retroreflectivity recording units and to analyse the observed retroreflectivity data to evaluate the state of pavement markings under investigation. The centreline pavement marking retrorefl/ectivity data collected by Queensland Department of Main Roads using the ECODYN mobile retroreflectivity recording unit are analysed to determine how the factors such as pavement surface type and traffic environment relate to retroreflectivity performance. It has been found that the mobile retroreflectivity recording unit with in-built processing capabilities can be implemented for identifying the requirements of maintenance programs, as well as to relate the observed retroreflectivity with other factors such as pavement surface type and traffic environment. The observed data indicated that there is a disparity between urban and rural roads of southeast Queensland in terms of centreline pavement marking retroreflectivity qualities. Asphalt surfaces, common in urban environments, were found to have average retroreflectivity over 200 mcd/m2/lux, whereas sprayed seal surfaces, common in rural environments, averaged below 170 mcd/m2/lux. About one-third of the roads used in the analysis fell below the generally accepted minimum threshold of 150 mcd/m2/lux at the time of observation.