80 research outputs found
Progress with the trial phase for registration of new plant names
In a spirit of co-operation and to publicise this proposed innovation in plant nomenclature widely in southern Africa, this note has been submitted simultaneously to the following botanical journals: Bothalia, South African Journal of Botany, Forum Botanicum and SAB-ONET News. A trial phase for the registration of new plant names in South Africa, co-ordinated by the International Association of Plant Taxonomy in Berlin, is introduced. Registration can be effected by publishing a new name in an accredited journal or series or by submitting it to the national Registration Office established for this purpose
Influence of alternating current electrokinetic forces and torque on the elongation of immobilized DNA
The authors investigate the elongation and orientation of different-sized deoxyribose nucleic acid (DNA) molecules, tethered onto gold electrodes via a terminal thiol, under the influence of high frequency ac electric fields. The DNA molecules are elongated from a random coil into an extended conformation and orientated along the electric field lines as a result of the forces acting on the molecules during the application of the ac electric fields. Elongation was observed in the frequency range 100 kHz-1 MHz, with field strengths of 0.06-1.0 MV/m. Maximum elongation for all DNA fragments tested, irrespective of size, was found for frequencies between 200 and 300 kHz. The torque acting on the induced dipole in the DNA molecules, complemented by a directional bias force, opposite in direction to the dielectrophoretic force, provides the main contribution to the elongation process. The length of elongation is limited to either half the distance between opposing electrodes or to the contour length of the DNA, whichever is shorter. Further, the authors show that the normalized length of the elongated DNA molecules is independent of the contour length of the DNA. (C) 2005 American Institute of Physics
Minipool Caprylic Acid Fractionation of Plasma Using Disposable Equipment: A Practical Method to Enhance Immunoglobulin Supply in Developing Countries
Plasma-derived immunoglobulin G (IgG) is on WHO’s Essential Medicines List, yet developing countries face severe shortages of this critical treatment. Infusion of IgG prepared from locally-collected plasma provides an advantageous mix of antibodies to viral and bacterial pathogens found in the living environment, and this can reduce recurrent infections in immune-deficient patients. We developed a simple manufacturing process using disposable equipment (blood bags, hemodialyzer, and filters) to isolate immunoglobulins from minipools of 20 plasma donations. This process yields a ca. 90% pure virally-inactivated immunoglobulin fraction at 50–60% recovery. Anti-hepatitis B and anti-rubella immunoglobulins were enriched fourfold to sixfold. The product was free of in-vitro thrombogenic and proteolytic activity, confirming its expected clinical safety profile. Virus validations showed caprylic acid treatment robustly inactivated or removed infectivity of lipid-enveloped viruses, including human immunodeficiency virus (HIV) and hepatitis C virus model. This simple and cost-effective process is implemented in Egypt to prepare experimental batches for clinical evaluation. It can enhance immunoglobulin supplies to treat immunodeficient patients through passive transmission of antibodies directed against local pathogens. The method requires minimal training and reasonable infrastructure, and is a practical means to prepare convalescent hyperimmune IgG during infectious outbreaks such as the current Ebola episode.UCR::VicerrectorÃa de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP)UCR::VicerrectorÃa de Docencia::Salud::Facultad de MicrobiologÃ
FABACEAE: A NEW SPECIES OF <i>PEARSONIA</i> FROM MPUMALANGA, SOUTH AFRICA
A NEW SPECIES OF PEARSONIA FROM MPUMALANGA, SOUTH AFRIC
FABACEAE: A NEW' SPECIES OF <i>RHYNCHOSIA</i> FROM SOUTH AFRICA
A NEW' SPECIES OF RHYNCHOSIA FROM SOUTH AFRIC
FABACEAE
CAESALPINIA BRACTEATA, A NEW SPECIES FROM THE ONSEEPKANS AREA OF THE NORTHERN CAPE PROVINC
Fabaceae
A new species of Rhynchosia from the northern provinces of South Africa
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