Nuclear radiation analysis

A study program of radiation shielding against the deleterious effects of nuclear radiation on man and equipment is reported. The methods used to analyze the radiation environment from bremsstrahlung photons are discussed along with the methods employed by transport code users. The theory and numerical methods used to solve transport of neutrons and gammas are described, and the neutron and cosmic fluxes that would be present on the gamma-ray telescope were analyzed

SNAP-8 post shutdown gamma radiation approximations

Detector responses were calculated for normalized sources in the Perkins and King energy group structure for a SNAP 8 power system on a NASA space station. Gamma decay rates were then calculated by using an expanded, updated list of isotopic decay data, and from these, actual detector responses were found for the SNAP 8 system. The results indicate that energy-dependent calculations must be made to determine decay gamma dose rates for actual reactor configurations. A simplified method for making these calculations has been devised

Monte Carlo variance reduction study

A mathematical analysis of the transport of nuclear radiation through matter is presented. A computer test bed that was developed is shown, along with flow charts

CAVEAT - A revised version of the general purpose Monte Carlo program, COHORT. Volume 1 - Theory and techniques

Revised version of general purpose Monte Carlo computer code for radiation transport calculations - theory and technique

CAVEAT - A revised version of the general purpose Monte Carlo program, COHORT Volume 2 - Users' manual

Revised version of general purpose Monte Carlo computer code for radiation transport calculations - users manua

Structural Properties, Order-Disorder Phenomena and Phase Stability of Orotic Acid Crystal Forms

Orotic acid (OTA) is reported to exist in the anhydrous (AH), monohydrate (Hy1) and dimethylsulfoxide monosolvate (SDMSO) forms. In this study we investigate the (de)hydration/desolvation behavior, aiming at an understanding of the elusive structural features of anhydrous OTA by a combination of experimental and computational techniques, namely, thermal analytical methods, gravimetric moisture (de)sorption studies, water activity measurements, X-ray powder diffraction, spectroscopy (vibrational, solid-state NMR), crystal energy landscape and chemical shift calculations. The Hy1 is a highly stable hydrate, which dissociates above 135°C and loses only a small part of the water when stored over desiccants (25°C) for more than one year. In Hy1, orotic acid and water molecules are linked by strong hydrogen bonds in nearly perfectly planar arranged stacked layers. The layers are spaced by 3.1 Å and not linked via hydrogen-bonds. Upon dehydration the X-ray powder diffraction and solid-state NMR peaks become broader indicating some disorder in the anhydrous form. The Hy1 stacking reflection (122) is maintained, suggesting that the OTA molecules are still arranged in stacked layers in the dehydration product. Desolvation of SDMSO, a non-layer structure, results in the same AH phase as observed upon dehydrating Hy1. Depending on the desolvation conditions different levels of order-disorder of layers present in anhydrous OTA are observed, which is also suggested by the computed low energy crystal structures. These structures provide models for stacking faults as intergrowth of different layers is possible. The variability in anhydrate crystals is of practical concern as it affects the moisture dependent stability of AH with respect to hydration

BIRS Course: RNA Vaccine Manufacture and Assessment of Regulatory Documents for RNA Vaccines

This paper is in three segments: (A) Segment on Vaccine Manufacture; (B) Segment on Ready to Use (RTU) Fluid Path for Compounded Sterile Preparations, mRNA Vaccines, and Phage Therapy, (C) Segment on Competency Framework for Addressing Regulatory Review These segments can be used separately or in combination. Additionally, they can be presented in any order. The time devoted to each segment depends on the depth of the course coverage. These segments are interrelated and describe how to make vaccines, how to manufacture vaccines with a point-of-care system built from ready-to-use parts; and how to regulate vaccines. This is a timely review because of the importance of vaccines for the treatment of diseases. It is hoped that it will lead to new approaches to vaccine manufacture and regulation

Medical Devices Regulation in West Africa – A Situation Analysis

Harmonization of medical devices regulation is receiving strong global attention through the International Medical Devices Regulator’s Forum, an offshoot of the Global Harmonization Task Force on medical devices. Other current trends include the Global Medical Devices Nomenclature and the Medical Devices Single Audit Program. The medical devices regulatory field is in a state of constant innovations; technologies and new regulations and guidelines are evolving to meet the changing needs and trends. This is a veritable development because medical devices and technologies are assuming significant strategic roles in the healthcare value chain – prevention, diagnostics, treatment and cure of diseases – in which they act as “force multipliers,” affecting the economics of healthcare. The questions then are – what is the situation of medical devices regulations in Africa? Is Africa trending along with the global harmonization of medical devices regulation? This research focuses on the state of medical devices regulations in West Africa. The research question is – what is the current state of medical devices regulations in West Africa. To answer this question, a review of publicly available data was conducted. First, the World Health Organization’s website was reviewed for the most current data on the status of West African countries’ medical devices regulations. Then, all the available websites of National Medicines Regulatory Authorities in West Africa were reviewed to ascertain their current medical devices regulatory status. The results show that West African countries are lagging behind in the regulation of medical devices. Only 28% and 17% of the countries have regulations and guidelines respectively. It is recommended that the international partners sensitize, educate and support the national medicines regulatory authorities in West Africa to build their regulatory framework for medical devices using the World Health Organization’s model

Human Capacity Building in Africa – The BIRS Model

Human capacity sufficiency and sustenance in regulatory science is a key factor for harmonization and an identified issue in the harmonization process specifically in Africa. The human factor is the linchpin for progress----there can be no working system without human capacity. Harmonization depends upon education that motivates and prepares individuals for leadership that subsequently fuels the profession. This paper proposes that one of the root causes is lack of sufficient institutions in Africa providing education in regulatory sciences and introduces the Biotechnology Innovation and Regulatory Sciences (BIRS) program model. This education model began with the IPAT program and evolved into the BIRS program of Purdue University. The goal of this program is to enable the manufacture of quality medicines in Africa for Africans by equipping leaders in Africa through higher education aligned with building industrial capacity. The program awards an MS degree from Purdue University in BIRS. These programs established a global professional community of regulatory scientists composed of Industrial Pharmacy Advanced Training (IPAT) graduates in Africa, Purdue MS graduates (from the US and Africa), PhD graduates, faculty, industry, and regulatory leaders. The community is diverse, including about 30% women and 50% Africans, and focuses on technical skills, leadership, regulatory science, and innovation. Currently, this community numbers over 350 members including about 200 graduates of Purdue’s certificate and master’s programs in the US, about 140 graduates of the IPAT certificate and Purdue’s master’s program in Africa, and professors, industry and regulatory leaders who have taught in the program over the years. In 10 years, the program has educated over 100 African scientists at the certificate level and over 40 African scientists at the MS level. Sponsorship of the program with funds and in kind has come from UNIDO, the Merck Foundation, and the Bill and Melinda Gates foundation