Results of twenty years of blood group research in south africa

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Analytical model for the uncorrelated emittance evolution of externally injected beams in plasma-based accelerators

This article introduces an analytical formalism for the calculation of the evolution of beam moments and the transverse emittance for beams which are externally injected into plasma wakefield accelerators. This formalism is then applied to two scenarios with increasing complexity - a single beam slice without energy gain and a single beam slice with energy gain, both propagating at a fixed co-moving position behind the driver. The obtained results are then compared to particle-in-cell (PIC) simulations as well as results obtained using an semi-analytic numerical approach (SANA). We find excellent agreement between results from the analytical model and from SANA and PIC

Matching small β\beta functions using centroid jitter and two beam position monitors

Matching to small beta functions is required to preserve emittance in plasma accelerators. The plasma wake provides strong focusing fields, which typically require beta functions on the mm-scale, comparable to those found in the final focusing of a linear collider. Such beams can be time consuming to experimentally produce and diagnose. We present a simple, fast, and noninvasive method to measure Twiss parameters in a linac using two beam position monitors only, relying on the similarity of the beam phase space and the jitter phase space. By benchmarking against conventional quadrupole scans, the viability of this technique was experimentally demonstrated at the FLASHForward plasma-accelerator facility.Comment: 8 pages, 7 figure

Preliminary results on electrophoretic and immunoelectrophoretic fractionation of bovine muscle extract

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A Novel Four-Gene Prognostic Signature for Prediction of Survival in Patients with Soft Tissue Sarcoma

Soft tissue sarcomas (STS), a group of rare malignant tumours with high tissue heterogeneity, still lack effective clinical stratification and prognostic models. Therefore, we conducted this study to establish a reliable prognostic gene signature. Using 189 STS patients’ data from The Cancer Genome Atlas database, a four-gene signature including DHRS3, JRK, TARDBP and TTC3 was established. A risk score based on this gene signature was able to divide STS patients into a low-risk and a high-risk group. The latter had significantly worse overall survival (OS) and relapse free survival (RFS), and Cox regression analyses showed that the risk score is an independent prognostic factor. Nomograms containing the four-gene signature have also been established and have been verified through calibration curves. In addition, the predictive ability of this four-gene signature for STS metastasis free survival was verified in an independent cohort (309 STS patients from the Gene Expression Omnibus database). Finally, Gene Set Enrichment Analysis indicated that the four-gene signature may be related to some pathways associated with tumorigenesis, growth, and metastasis. In conclusion, our study establishes a novel four-gene signature and clinically feasible nomograms to predict the OS and RFS. This can help personalized treatment decisions, long-term patient management, and possible future development of targeted therapy

Wakefield-Induced Ionization injection in beam-driven plasma accelerators

We present a detailed analysis of the features and capabilities of Wakefield-Induced Ionization (WII) injection in the blowout regime of beam driven plasma accelerators. This mechanism exploits the electric wakefields to ionize electrons from a dopant gas and trap them in a well-defined region of the accelerating and focusing wake phase, leading to the formation of high-quality witness-bunches [Martinez de la Ossa et al., Phys. Rev. Lett. 111, 245003 (2013)]. The electron-beam drivers must feature high-peak currents ($I_b^0\gtrsim 8.5~\mathrm{kA}$) and a duration comparable to the plasma wavelength to excite plasma waves in the blowout regime and enable WII injection. In this regime, the disparity of the magnitude of the electric field in the driver region and the electric field in the rear of the ion cavity allows for the selective ionization and subsequent trapping from a narrow phase interval. The witness bunches generated in this manner feature a short duration and small values of the normalized transverse emittance ($k_p\sigma_z \sim k_p\epsilon_n \sim 0.1$). In addition, we show that the amount of injected charge can be adjusted by tuning the concentration of the dopant gas species, which allows for controlled beam loading and leads to a reduction of the total energy spread of the witness beams. Electron bunches, produced in this way, fulfil the requirements to drive blowout regime plasma wakes at a higher density and to trigger WII injection in a second stage. This suggests a promising new concept of self-similar staging of WII injection in steps with increasing plasma density, giving rise to the potential of producing electron beams with unprecedented energy and brilliance from plasma-wakefield accelerators

Blood groups in bovines. II. Normally occurring isoantibodies in cattle blood

One type of normally occurring isoantibodies in cattle serum, which has not been described before and which corresponds perfectly with the immune anti-Y₂, has been demonstrated. A seasonal variation of normally occurring isoantibodies has been established. In all groups of animals, the highest titres were found to be present during the late summer and the lowest titres during the late winter. There appears to be no difference between sexes and among breeds in this seasonal variation, which is not influenced by feeding. A correlation of climatological factors and naturally occurring isoantibodies was made and it is believed that radiation and temperature may have an influence on the seasonal variation of normal antibodies. An experiment was carried out to exclude any form of light influence on six animals with normally occurring isoantibodies in their serum. In spite of this the seasonal variation in their antibody level was found to be similar to that in a control group exposed to light. It appears that of the climatic factors temperature has the most stimulating effect on the production of antibodies, but that a retardation of about two to three months takes place in the antibody producing systems. Any gradual change in temperature appears to be effective in bringing about an increase or decrease in the level of normally occurring isoantibodies. A corresponding variation of antibodies against Brucella abortus to that of normally occurring isoantibodies could be demonstrated.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

Blood groups in bovines. I. Production of cattle iso-immune sera and blood group reagents

A short introduction is given to the field of bovine blood group research. Some of the immunological terms used in immuno-genetics are explained. The genetic aspects are briefly dealt with. The methods used for the production of iso-immune sera are described. An analysis is made of the different sources of genetical and environmental variation in antibody production, and from this it is concluded that it is impossible to give detailed directives for their production. The difficulties of testing sera under high temperature conditions are dealt with. It is concluded that these difficulties can be overcome in South Africa only by carrying out all blood group work in an air conditioned laboratory. The fractionation of different antisera is presented in Table No. 6. As a result of basic investigations in South Africa, three new types of antibodies have been isolated in Afrikaner cattle, which react with three so far unknown antigenic blood factors. Only a few test sera could not be produced. Through international cooperation between blood group laboratories and particularly through exchanges of test sera, the South African laboratory was able to start routine blood group determinations. for different practical purposes and genetical studies, in 1958.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format