Comparison of capsule-mixed versus hand-mixed glass ionomer cements Part 1: compressive strength and surface hardness

Dental restorative glass ionomer cements (GIC) are available as hand-mixed or capsulated products. Capsulation facilitates uniform ratios of powder to liquid, that should result in an optimal end-product. If this is evident, the degree to which capsulated GIC are mechanically stronger will aid in deciding when to use them instead of the handmixed variety. The compressive strength and surface hardness of handmixed GIC were compared to capsule-mixed equivalents. Eighty samples were manufactured from hand-mixed GIC: Riva Self Cure; Fuji IX GP; Ketac Universal, Ketac Molar Easymix, and equivalent capsule-mixed GIC: Riva Self Cure; Fuji IX GP; Ketac Universal Aplicap and Ketac Molar Aplicap. Compressive fracture strength was tested using a universal testing apparatus. Surface hardness was measured with a Vickers digital micro-hardness tester Significant differences were found between the compressive strength of RSCH and RSCC (P = 0.027), and, between KMH and KMC (P < 0.001). Significant differences in surface hardness were found between FIXH and FIXC (P = 0.031),KUH and KUC (P < 0.001), as well as KMH and KMC (P = 0.006). Three capsulated forms of GIC (RSCC, KUC, KMC) demonstrated superior mechanical properties. Capsulated GIC offer advantages which may translate to clinical application

Rickettsia felis DNA recovered from a child who lived in southern Africa 2000 years ago

DATA AVAILABILITY : Raw reads from Ballito Bay A samples are available under the NCBI BioProject PRJEB22660. The R. felis BBayA mapped reads and the metagenome-assembled genome are available under the NCBI BioProject PRJNA930765. The NCBI WGS accession number is JAQQRK000000000.The Stone Age record of South Africa provides some of the earliest evidence for the biological and cultural origins of Homo sapiens. While there is extensive genomic evidence for the selection of polymorphisms in response to pathogen-pressure in sub-Saharan Africa, e.g., the sickle cell trait which provides protection against malaria, there is inadequate direct human genomic evidence for ancient human-pathogen infection in the region. Here, we analysed shotgun metagenome libraries derived from the sequencing of a Later Stone Age hunter-gatherer child who lived near Ballito Bay, South Africa, c. 2000 years ago. This resulted in the identification of ancient DNA sequence reads homologous to Rickettsia felis, the causative agent of typhus-like flea-borne rickettsioses, and the reconstruction of an ancient R. felis genome.A National Geographic Society Scientific Exploration Grant, the Oppenheimer Endowed Fellowship in Molecular Archaeology, the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme and the Knut and Alice Wallenberg Foundation.https://www.nature.com/commsbiohj2023BiochemistryGeneticsMicrobiology and Plant Patholog

Die gedrag van Amerikaanse regstreekse buitelandse belegging in Suid-Afrika, 1985-hede

M. Com. (Economics)The objective of the study was to examine the behaviour of American foreign direct investment in South Africa since 1985. By the mid- eighties more than 300 American companies had direct investments or employees in South Africa. During the period 1984-1991, 215 of these companies withdrew from South Africa. Most of them sold their affiliates to local investors or local companies. Some sold their affiliates to non- South African companies. A few liquidated their South African operations while others sold their assets to trusts. Most of the companies that withdrew from South Africa maintained licensing and other contractual agreements with their former affiliates. No American company established new affiliates in South African during the period 1984-1991. During the period July 1991 - February 1994, 39 American companies settled in South Africa. Some of them were companies that withdrew from South Africa during the sanctions period. The number of companies re-entering the country could, however, be misleading. Only a few of these companies established manufacturing plants locally. The new settlement was not accompanied by a significant inflow of capital or the employment of large numbers of workers..

Die invloed van die VSA-dollar op die mededingende voordeel van Suid-Afrika

D.Com. (Economics)The objective of the study was mainly to examine the effect of the U.S. dollar on the competitive advantage of South Africa.The theoretical framework explaining the competitive position of a country in the global market place was examined in Chapter II. The complexity of the variables involved is evident from the many different points of view put forward by economists, not only in respect of the. concept competitive advantage of a country, but also in respect of the criteria that should be used to evaluate such competitiveness. It is, however, evident that the phenomena involved in evaluating the competitive position of a country cannot be separated from the theories explaining the flow of goods and services between countries. Only a minor part of such flows can be explained in terms of the traditional international trade theories. Most of the trade over borders occurs between countries differing very little from each other as far as tastes and factor ..

Rickettsia felis DNA recovered from a child who lived in southern Africa 2000 years ago

The Stone Age record of South Africa provides some of the earliest evidence for the biological and cultural origins of Homo sapiens. While there is extensive genomic evidence for the selection of polymorphisms in response to pathogen-pressure in sub-Saharan Africa, e.g., the sickle cell trait which provides protection against malaria, there is inadequate direct human genomic evidence for ancient human-pathogen infection in the region. Here, we analysed shotgun metagenome libraries derived from the sequencing of a Later Stone Age hunter-gatherer child who lived near Ballito Bay, South Africa, c. 2000 years ago. This resulted in the identification of ancient DNA sequence reads homologous to Rickettsia felis, the causative agent of typhus-like flea-borne rickettsioses, and the reconstruction of an ancient R. felis genome