Novel optical imaging technique to determine the 3-D orientation of collagen fibers in cartilage: variable-incidence angle polarization-sensitive optical coherence tomography

Objective: To investigate a novel optical method to determine the three dimensional (3-D) structure of articular cartilage collagen non-destructively. Methods: Polarization-sensitive optical coherence tomography was used to determine the apparent optical birefringence of articular cartilage for a number of different illumination directions. A quantitative method based on the theory of light propagation in uniaxial crystalline materials was validated on equine flexor tendon. Qualitative maps of fiber polar and azimuthal orientation at sites on the posterior and anterior segments of the equine third metacarpophalangeal (fetlock) joint were produced, and the azimuthal orientations compared with data from a split-line experiment. Results: Polar and azimuthal angles of cut flexor tendon broadly agreed with the nominal values but suggested that the accuracy was limited by our method of determining the apparent birefringence. On intact equine fetlock joints we found a non-zero polar tilt that changed in direction at various points along the apex, moving from the sagittal ridge outwards. The azimuthal orientation changes from being parallel to the sagittal ridge in the posterior region to being inclined to the ridge in the anterior region. This broadly agrees with split-line data for the anterior region but differs in the posterior region, possibly reflecting depth-dependent orientation changes. Conclusion: General quantitative agreement was found between our method and histology in validation experiments. Qualitative results for cartilage suggest a complicated 3-D structure that warrants further study. There is potential to develop this approach into a tool that can provide depth-resolved information on collagen orientation in near real-time, non-destructively and in vivo. (c) 2008 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved

Analysis of the success of ICT at the Ikageng MPCC in support of the Itsoseng community : a case study

Information and communication technology is changing every facet of our lives, and thus changing how we live. This in turn impacts on the way we utilise information and communication technology in multi-purpose community centres, which provide support services to the communities in which they are located. A case study was conducted at the information and communication technology equipped Ikageng Multi-purpose Community Centre in Itsoseng, situated in the North West Province of South Africa, to investigate the services delivered; the Centre utilises information and communication technology infrastructure to deliver needed services to the community. The lack of ongoing and sustained training for Centre staff, as well as the challenge of maintaining the Centre’s equipment, were some of the shortcomings identified by the study in terms of service delivery

Final report: Photochromism as a switching mechanism for electronically active organic materials

Recent discoveries in the field of conjugated polymers in environmental stability, regiochemical regularity, and electrical conductivity, particularly of polythiophene and polyaniline, have intensified interest in device applications. Present or anticipated applications include development of electrical circuitry on a molecular scale, as well as conducting and semiconducting materials for a variety of applications including thin film transistors and batteries. The authors have investigated a series of compounds comprising conjugated segments coupled to photochromic elements. The photochromic reaction in these compounds reversibly alters the conjugation length and provides a mechanism for switching both the electrical and optical properties of these materials. The authors are currently investigating the nature and scope of this switching mechanism and preparing extended materials that take advantage of this novel form of switching behavior. Preparation and photochromic behavior of several of these materials are described

Bovine skin lesions of possible filarial origin associated with heavy hornfly infestations (Haematobia meridiana)

Circumscribed, ulcerative skin lesions, usually situated caudal to the scapula, affected cattle in the Republic of Venda during the summer of 1981-82. The occurrence of the lesions was associated with heavy infestations of the hornfly, Haematobia meridiana. Microscopically the lesions were characterized by intense eosinophilic dermatitis. Microfilariae were seen in histological sections of one lesion, but a species identification could not be made. The possible cause of the lesions is discussed.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Psychiatric nurse practitioners' experiences of working with mental health care users presenting with acute symptoms

Psychiatric nurse practitioners (PNPs) working with mental health care users presenting with acute symptoms work in a complex environment. This environment is characterised by mental health care users who may present with a history of violence, sexual assault and substance misuse. The objectives of this study were twofold: firstly, to explore and describe the experiences of PNPs working with mental health care users (MHCUs) presenting with acute symptoms; and secondly, to make recommendations for the a vanced PNPs to facilitate promotion of the mental health of PNPs with reference to nursing practice, research and education. A qualitative, explorative, descriptive and contextual design was used. The target population was PNPs working with MHCUs presenting with acute symptoms in a public mental health care institution in Gauteng. Data were collected by means of four focus group interviews involving 21 PNPs. The researcher made use of drawings, naïve sketches and field notes for the purpose of data triangulation. Data were analysed in accordance with Tesch’s method of open coding. The three themes that emerged were: PNPs experienced working with these MHCUs as entering an unsafe world where care became a burden; they experienced negative emotional reactions and attitudes towards these MHCUs that compromised quality nursing care; and they made a plea for a nurturing environment that would enhance quality nursing care. The PNPs suggest skills and competency development, organisational support, and a need for external resources. Creation of a positive environment and mobilisation of resources as well as the identification and bridging of obstacles are essential in the promotion of the overall wellbeing and mental health of PNPs.J.K.N. (University of Pretoria & South Africa Medical Research Council) was a Master’s candidate, E.v.R. (University of Pretoria) was a Supervisor, and S.M. (University of Pretoria) was a co-supervisor.http://www.curationis.org.zaam2013ay201

Толерантный подход к теме греко-турецких взаимоотношений в новейшей греческой прозе

Целью данной статьи стало рассмотрение нового видения дихотомии «грек-турок» в романах греческих писателей второй половины ХХ века

Blood-brain barrier leakage and microvascular lesions in cerebral amyloid angiopathy

Background and Purpose-Cerebral amyloid angiopathy (CAA) is a common small vessel disease that independently effects cognition in older individuals. The pathophysiology of CAA and CAA-related bleeding remains poorly understood. In this postmortem study, we explored whether blood-brain barrier leakage is associated with CAA and microvascular lesions.Methods-Eleven CAA cases (median [IQR] age=69 years [65-79 years], 8 males) and 7 cases without neurological disease or brain lesions (median [IQR] age=77 years [68-92 years], 4 males) were analyzed. Cortical sections were sampled from each lobe, and IgG and fibrin extravasation (markers of blood-brain barrier leakage) were assessed with immunohistochemistry. We hypothesized that IgG and fibrin extravasation would be increased in CAA cases compared with controls, that this would be more pronounced in parietooccipital brain regions compared with frontotemporal brain regions in parallel with the posterior predilection of CAA, and would be associated with CAA severity and number of cerebral microbleeds and cerebral microinfarcts counted on ex vivo magnetic resonance imaging of the intact brain hemisphere.Results-Our results demonstrated increased IgG positivity in the frontotemporal (P=0.044) and parietooccipital (P=0.001) cortex in CAA cases compared with controls. Within CAA cases, both fibrin and IgG positivity were increased in parietooccipital brain regions compared with frontotemporal brain regions (P=0.005 and P=0.006, respectively). The percentage of positive vessels for fibrin and IgG was associated with the percentage of amyloid-beta-positive vessels (Spearman.=0.71, P=0.015 and Spearman.=0.73, P=0.011, respectively). Moreover, the percentage of fibrin and IgGpositive vessels, but not amyloid-beta-positive vessels, was associated with the number of cerebral microbleeds on magnetic resonance imaging (Spearman.=0.77, P=0.005 and Spearman.=0.70, P=0.017, respectively). Finally, we observed fibrin deposition in walls of vessels involved in cerebral microbleeds.Conclusions-Our results raise the possibility that blood-brain barrier leakage may be a contributory mechanism for CAArelated brain injury

Phase fluctuations, dissipation and superfluid stiffness in d-wave superconductors

We study the effect of dissipation on quantum phase fluctuations in d-wave superconductors. Dissipation, arising from a nonzero low frequency optical conductivity which has been measured in experiments below $T_c$, has two effects: (1) a reduction of zero point phase fluctuations, and (2) a reduction of the temperature at which one crosses over to classical thermal fluctuations. For parameter values relevant to the cuprates, we show that the crossover temperature is still too large for classical phase fluctuations to play a significant role at low temperature. Quasiparticles are thus crucial in determining the linear temperature dependence of the in-plane superfluid stiffness. Thermal phase fluctuations become important at higher temperatures and play a role near $T_c$.Comment: Presentation improved, new references added (10 latex pages, 3 eps figures). submitted to PR

New York: the animated city

The urban landscape of New York City is one that is familiar to many, but, through the medium of animation, this familiarity has been consistently challenged. Often metamorphic, and always meticulously constructed, animated imagery encourages reflective thinking. Focusing on the themes of construction, destruction, and interactivity, this article seeks to cast critical light upon the animated double life that New York City has lived through the following moving image texts: Disney’s Fantasia 2000 (1999), Patrick Jean’s computer-generated short Pixels (2009), and Rockstar Games’ open-world blockbuster Grand Theft Auto IV (2008)

4pi Models of CMEs and ICMEs

Coronal mass ejections (CMEs), which dynamically connect the solar surface to the far reaches of interplanetary space, represent a major anifestation of solar activity. They are not only of principal interest but also play a pivotal role in the context of space weather predictions. The steady improvement of both numerical methods and computational resources during recent years has allowed for the creation of increasingly realistic models of interplanetary CMEs (ICMEs), which can now be compared to high-quality observational data from various space-bound missions. This review discusses existing models of CMEs, characterizing them by scientific aim and scope, CME initiation method, and physical effects included, thereby stressing the importance of fully 3-D ('4pi') spatial coverage.Comment: 14 pages plus references. Comments welcome. Accepted for publication in Solar Physics (SUN-360 topical issue