Sub-Criticality Measurement with Source Term for Research Reactor in Inverse Kinetics Method

In reactor physics tests, it is important to monitor sub-criticality continuously during criticality approach. Reactivity measurements by the inverse kinetics method are widely used during the operation of a nuclear reactor. This technique is successfully applied at sufficiently high power level or to a core without an external neutron source where the neutron source term in point reactor kinetics equations may be neglected. For operation at low power levels or in the sub-critical domain, the increase in the fluctuation of the neutron signal may cause difficulties in the evaluation of reactivity and the effect of direct emission from the external neutron source may not be neglected. Therefore, contribution of the neutron source must be taken into account and this implies knowledge of a quantity proportional to the source strength, which calls the source term and then it should be determined. The research work has been conducted to measure reactivity with source term using a dedicated reactivity measurement system by the Least Square Inverse Kinetics Method (LSIKM). Application to a simulator of HANARO research reactor, Korea Atomic Energy Research Institute (KAERI), with known source strength and reactivity worth has showed consistent and satisfactory agreement.

Neutron Flux Signal Acquisition from Plant Instrumentation Channel of Research Reactor for Reactivity Calculation

A design for instantaneous neutron flux signal acquisition system is being carried out for reactivity measurement of the nuclear research reactor. It is a computer-based digital data acquisition system that can perform continuous monitor and measurement of reactivity inserted into or removed from the research reactor. The acquisition system accomplishes with two major parts. The first part is an interfacing PCI based data acquisition card and the corresponding driver software intending to on-line acquisition of neutron flux signals from plant instrumentation channel. The second part incorporates the high-level Visual Basic real time program, indigenously developed for computation of reactivity by the solution of neutron point kinetic equations and other relevant functional modules like input file logging, reactivity calculation, graphics demonstration etc.

Elucidating authorship issues as an element of research quality at Thailand’s National Science and Technology Development Agency

Authorship in a scientific publication is an indicator of significant intellectual contribution in scientific work.Regardless of the discipline,it is important for research-related personnel to receive credit and take responsibility for their publications.There are currently several systems of listing authorship that arise from many factors such as research complexity,pressure to obtain funding,hierarchical structure,and promotion.Some of these may unfortunately lead to authorship abuse.Raising awareness and understanding of authorship guidelines can help prevent abuses and disputes.National Science and Technology Development Agency(NSTDA)is a national research agency of Thailand with about 2000 research staff members.The research emphasis of the agency is mainly technology development for application in broad areas,ranging from engineering to medicine,including forensic science.We conducted a survey to identify the level of awareness of NSTDA research staff and their authorship practices.A questionnaire was designed based on the International Committee of Medical Journal Editors(ICMJE)authorship guidelines and used to survey 15%of randomly selected NSTDA research staff.Nearly 90%of them responded to the interview.Among the respondents,60%were not sure about authorship criteria.When presented with the ICMJE criteria,more than 90%agreed with the criteria except for the third one,approval of the final manuscript before submission,33%of respondents thought that authors are only responsible for their particular contribution.However,nearly 80%agreed that every author is responsible for the integrity of the whole manuscript.These results offered an important foundation for forming a strategy to raise awareness about authorship in NSTDA.Following survey analysis,we organized several seminars and developed learning materials and an authorship guideline to increase the level of awareness of authorship for researchers.

CD4＋VEGFR1HIGH T cell as a novel Treg subset regulates inflammatory bowel disease in lymphopenic mice

Regulatory T cells （Tregs） are a specialized subpopulation of T cells that control the immune response and thereby maintain immune system homeostasis and tolerance to self-antigens. Many subsets of CD4＋ Tregs have been identified, including Foxp3~, Trl, Th3, and Foxp3neg iT（R）35 cells. In this study, we identified a new subset of CD4＋VEGFR1high Tregs that have immunosuppressive capacity. CD4＋VEGFRlhigh T cells, which constitute approximately 1.0% of CD4＋ T cells, are hyporesponsive to T-cell antigen receptor stimulation. Surface marker and FoxP3 expression analysis revealed that CD4＋VEGFR1high T cells are distinct from known Tregs. CD4＋VEGFR1high T cells suppressed the proliferation of CD4＋CD25- T cell as efficiently as CD4＋CD25high natural Tregs in a contact-independent manner. Furthermore, adoptive transfer of CD4＋VEGFR1＋ T cells from wild type to RAG-2-deficient C57BL/6 mice inhibited effector T-cell-mediated inflammatory bowel disease. Thus, we report CD4＋ VEGFR1high T cells as a novel subset of Tregs that regulate the inflammatory response in the intestinal tract.