Structure and properties of ilmenite from first principles

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Evaluation of a Desktop 3D Printed Rigid Refractive-Indexed-Matched Flow Phantom for PIV Measurements on Cerebral Aneurysms

Purpose Fabrication of a suitable flow model or phantom is critical to the study of biomedical fluid dynamics using optical flow visualization and measurement methods. The main difficulties arise from the optical properties of the model material, accuracy of the geometry and ease of fabrication. Methods Conventionally an investment casting method has been used, but recently advancements in additive manufacturing techniques such as 3D printing have allowed the flow model to be printed directly with minimal post-processing steps. This study presents results of an investigation into the feasibility of fabrication of such models suitable for particle image velocimetry (PIV) using a common 3D printing Stereolithography process and photopolymer resin. Results An idealised geometry of a cerebral aneurysm was printed to demonstrate its applicability for PIV experimentation. The material was shown to have a refractive index of 1.51, which can be refractive matched with a mixture of de-ionised water with ammonium thiocyanate (NH4SCN). The images were of a quality that after applying common PIV pre-processing techniques and a PIV cross-correlation algorithm, the results produced were consistent within the aneurysm when compared to previous studies. Conclusions This study presents an alternative low-cost option for 3D printing of a flow phantom suitable for flow visualization simulations. The use of 3D printed flow phantoms reduces the complexity, time and effort required compared to conventional investment casting methods by removing the necessity of a multi-part process required with investment casting techniques

Intra-rater agreement for the 6-group geometric classification: 3 evaluators.

<p>Intra-rater agreement for the 6-group geometric classification: 3 evaluators.</p

Geometric classification of scalp hair for valid drug testing, 6 more reliable than 8 hair curl groups

<div><p>Introduction</p><p>Curly hair is reported to contain higher lipid content than straight hair, which may influence incorporation of lipid soluble drugs. The use of race to describe hair curl variation (Asian, Caucasian and African) is unscientific yet common in medical literature (including reports of drug levels in hair). This study investigated the reliability of a geometric classification of hair (based on 3 measurements: the curve diameter, curl index and number of waves).</p><p>Materials and methods</p><p>After ethical approval and informed consent, proximal virgin (6cm) hair sampled from the vertex of scalp in 48 healthy volunteers were evaluated. Three raters each scored hairs from 48 volunteers at two occasions each for the 8 and 6-group classifications. One rater applied the 6-group classification to 80 additional volunteers in order to further confirm the reliability of this system. The Kappa statistic was used to assess intra and inter rater agreement.</p><p>Results</p><p>Each rater classified 480 hairs on each occasion. No rater classified any volunteer’s 10 hairs into the same group; the most frequently occurring group was used for analysis. The inter-rater agreement was poor for the 8-groups (k = 0.418) but improved for the 6-groups (k = 0.671). The intra-rater agreement also improved (k = 0.444 to 0.648 versus 0.599 to 0.836) for 6-groups; that for the one evaluator for all volunteers was good (k = 0.754).</p><p>Conclusions</p><p>Although small, this is the first study to test the reliability of a geometric classification. The 6-group method is more reliable. However, a digital classification system is likely to reduce operator error. A reliable objective classification of human hair curl is long overdue, particularly with the increasing use of hair as a testing substrate for treatment compliance in Medicine.</p></div

Intra-rater agreement for the 8-group geometric classification: 3 evaluators.

<p>Intra-rater agreement for the 8-group geometric classification: 3 evaluators.</p

Archives in the trenches: repatriation of African National Congress liberation archives in diaspora to South Africa

Please access the full-text of this article at the doi link at the top of this record.The African National Congress (ANC) liberation archives were created in countries all over the world. These liberation archives form part of the national archival heritage of South Africa as they bridge the gap of undocumented history of people who were previously marginalised by the apartheid government. After the ban on liberation movements was lifted in South Africa, the ANC embarked on the process of identification and repatriation of the records that were fragmented throughout the world. This study investigated the approaches followed by the ANC in identifying and repatriating its liberation archives from the trenches to make them accessible. Qualitative data were collected through interviews with purposively selected employees of the African National Congress, MultiChoice, Africa Media Online and the Nelson Mandela Foundation who were involved in the repatriation of the liberation archives. Interview data were augmented through content analysis of ANC documents such as policies, websites and annual reports, as well as observation of the storage conditions of the liberation archives. The key findings revealed that the ANC stablished an archives management committee that played an important role in the identification, repatriation and, ultimately, digitisation of liberation archives. The committee utilised former liberation struggle members to identify records in ANC hosts in various countries. It was established that, although the ANC was aware of where its records were abroad, not all its records were repatriated to South Africa after the unbanning of the liberation movements. For example, there were host nations, like Italy, that disputed the return of the ANC liberation archives to South Africa. The liberation archives are in the custody of the Fort Hare University as a chosen official repository for the ANC. It is concluded that the repatriation of the liberation archives is an ongoing process, as not all records have been repatriated to South Africa. As the ANC is in power at the time of writing, this is the opportunity for the organisation to negotiate with countries that still have custody of its liberation archives, such as Italy, to repatriate such records to South Africa. A further study on legal ownership and copyright, digitisation and ensuring the authenticity of the ANC liberation archives is recommended. This study can be extended to other liberation movements in southern Africa.Information Scienc

Inter-rater agreement for the 6-group geometric classification: 3 evaluators at occasion 1 and occasion 2.

<p>Inter-rater agreement for the 6-group geometric classification: 3 evaluators at occasion 1 and occasion 2.</p

Intra-rater agreement for the 6-group geometric classification: 3 evaluators.

<p>Intra-rater agreement for the 6-group geometric classification: 3 evaluators.</p

Demographics of sample population (n = 128) across 8 hair curl groups.

<p>Same number (10) of hair 6cm in length—each sample is representative of individuals geometrically classified into groups I–VIII using 3 measurements (curve diameter, curl meter, number of waves).</p