医療応用を指向した双性イオン分子で保護した金属ナノマテリアルの創製

関西大

Influence of Type and Compositions of SCMs on Expansion of Mortar Bars from Alkali Silica Reaction

The effect of different local pozzolans, as a supplementary cementitious material (SCM), on the expansion of mortar bar due to Alkali Silica Reaction (ASR) were reported in this paper. Accelerated test on specimens using local volcanic aggregates, rhyolite, was used to investigate and to compare the effects of fly ash (FA) and metakaolin (MK) on the suppression of the length change. In this study, three different percentages of FA, namely, 20, 35 and 50 and three of MK, namely, 10, 15 and 20 were used in cement replacement. The results showed the lowest expansions at 14 days were -0.036% and -0.001%, respectively for 35% FA and 10% MK, compared to 0.176 % of the control mix. Results from 28 days acceleration registered a slight increase in expansion for both FA and MK mixes.  Increase the SCMs to 50% FA and 15-20% MK yielded reduction of expansion to the innocuous level for both short and long term expansion. Chemical composition analysis revealed decrease in CaO/SiO2 and CaO/Al2O3 of the cementitious systems. This could affect the expansion reduction.  But alumina in Al2O3/SiO2 show the dominant effect on ASR suppression. Microstructures of all materials and casted specimens were also studied in detail. Considering all aspects, these SCMs were considered good candidates for ASR prevention in new concrete structures

การพัฒนาความสามารถในการสร้างแบบจำลองทางวิทยาศาสตร์ เรื่อง ปัจจัยที่มีผลต่ออัตราการเกิดปฏิกิริยาเคมี ด้วยการจัดการเรียนรู้แบบสืบเสาะหาความรู้โดยใช้แบบจำลองเป็นฐานร่วมกับภาพเคลื่อนไหวที่สร้างขึ้น

รับบทความ: 20 ตุลาคม 2565; แก้ไขบทความ: 19 กุมภาพันธ์ 2566; ยอมรับตีพิมพ์: 27 กุมภาพันธ์ 2566; ตีพิมพ์ออนไลน์: 28 พฤษภาคม 2566   บทคัดย่อ การเรียนรู้และเข้าใจแบบจำลองทางวิทยาศาสตร์เป็นหัวใจสำคัญอย่างหนึ่งของการเรียนวิทยาศาสตร์ โดยเฉพาะอย่างยิ่งในวิชาเคมี เนื่องจากเนื้อหาวิชาเคมีส่วนใหญ่ค่อนข้างซับซ้อนยากต่อการทำความเข้าใจ หากนักเรียนเข้าใจแบบจำลองและสามารถสร้างแบบจำลองได้จะสามารถเข้าใจเนื้อหาวิชาเคมีได้ง่ายขึ้น งานวิจัยนี้มีวัตถุประสงค์เพื่อพัฒนาความสามารถในการสร้างแบบจำลองทางวิทยาศาสตร์ เรื่อง ปัจจัยที่มีผลต่ออัตราการเกิดปฏิกิริยาเคมีของนักเรียนชั้นมัธยมศึกษาปีที่ 5 ด้วยการจัดการเรียนรู้แบบสืบเสาะหาความรู้โดยใช้แบบจำลองเป็นฐานร่วมกับภาพเคลื่อนไหวที่ผู้วิจัยได้สร้างขึ้น กลุ่มเป้าหมายคือนักเรียนชั้นมัธยมศึกษาปีที่ 5 จำนวน 30 คน เครื่องมือที่ใช้ในการวิจัยคือ 1) แผนการจัดการเรียนรู้ 2) ภาพเคลื่อนไหว 3) แบบวัดการสร้างแบบจำลองทางวิทยาศาสตร์ 4) แบบสัมภาษณ์กึ่งโครงสร้าง และ 5) อนุทิน การศึกษาในครั้งนี้เป็นวิจัยเชิงคุณภาพ โดยศึกษาความสามารถในการสร้างแบบจำลองทางวิทยาศาสตร์ก่อนและหลังการจัดการเรียนรู้ จากการวิจัยพบว่าก่อนเรียนนักเรียนส่วนใหญ่มีความสามารถในการสร้างแบบจำลองทางวิทยาศาสตร์อยู่ในระดับควรปรับปรุง หลังการจัดการเรียนรู้นักเรียนส่วนใหญ่มีความสามารถในการสร้างแบบจำลองทางวิทยาศาสตร์อยู่ในระดับดีมาก กิจกรรมการเรียนรู้ช่วยพัฒนาความสามารถในการสร้างแบบจำลองทางวิทยาศาสตร์ของนักเรียนได้ดียิ่งขึ้นในทุกองค์ประกอบ และภาพเคลื่อนไหวที่ผู้วิจัยสร้างขึ้นสามารถช่วยส่งเสริมให้นักเรียนเข้าใจพฤติกรรมของสารในระดับโมเลกุลมากขึ้น คำสำคัญ:  แบบจำลองทางวิทยาศาสตร์  ปัจจัยที่มีผลต่ออัตราการเกิดปฏิกิริยาเคมี  ภาพเคลื่อนไหว   Abstract Learning and understanding scientific models are the heart of learning science, especially in chemistry, since most of the chemistry content is quite complicated to understand. If students understand modeling and create modeling, it will be easier to understand the chemistry content. The purpose of this research was to develop students’ construction scientific model ability. The target group was 30 grade–11 students. Research instruments were composed of: 1) lesson plans, 2) animations, 3) scientific model ability tests of factors effecting chemical reaction rate, 4) interview and 5) reflection notes. This study was qualitative research to examine students’ ability to create scientific modeling before and after learning. According to the research, it was found that before studying, the students’ ability to create science models was at an improved level. After the learning process, the students were able to create scientific models at an excellent level. The results showed that the quest for knowledge using model–based learning together with animation improved students’ ability to create scientific models in all aspects, and the animations created by the researcher can encourage students to understand the behavior of substances at the molecular level and reaction rates. Keywords:  Scientific modeling, Factors affecting chemical reaction rate, Animation

Food-Like Growth Conditions Support Production of Active Vitamin B12 by Propionibacterium freudenreichii 2067 without DMBI, the Lower Ligand Base,or Cobalt Supplementation

Propionibacterium freudenreichii is a traditional dairy bacterium and a producer of short chain fatty acids (propionic and acetic acids) as well as vitamin B12. In food applications, it is a promising organism for in situ fortification with B12 vitamin since it is generally recognized as safe (GRAS) and it is able to synthesize biologically active form of the vitamin. In the present study, vitamin B12 and pseudovitamin biosynthesis by P. freudenreichii was monitored by UHPLC as a function of growth in food-like conditions using a medium mimicking cheese environment, without cobalt or 5,6-dimethylbenzimidazole (DMBI) supplementation. Parallel growth experiments were performed in industrial-type medium known to support the biosynthesis of vitamin B12. The production of other key metabolites in the two media were determined by HPLC, while the global protein production was compared by gel-based proteomics to assess the effect of growth conditions on the physiological status of the strain and on the synthesis of different forms of vitamin. The results revealed distinct protein andmetabolite production, which reflected the growth conditions and the potential of P. freudenreichii for synthesizing nutritionally relevant amounts of active vitamin B12 regardless of the metabolic state of the cells.Peer reviewe

ผลของกลาสไอดอดนเมอร์ซีเมนต์ชนิดใหม่ต่อเซลล์สร้างกระดูกมนุษย์

Thesis (Ph.D. (Molecular Biology and Bioinforatics))--Prince of Songkla University 201

Using bioconjugation reactions for protein detection, intracellular delivery, and the study of protein conformation

The synthetic modification of proteins has significantly contributed in the fields of chemical biology and material science. Choosing an appropriate chemical strategy that involves the controlled coupling of biomolecules in aqueous solution and in a well-defined manner is key. This work describes the use of suitable bioconjugation reactions for a variety of applications. Firstly, oxidative coupling of o-aminophenols and anilines was used for the detection of nitrotyrosine-containing proteins. In this work, we demonstrated that the chemoselectivity of the tandem nitro reduction/oxidative coupling sequence was sufficiently high to label nitrated proteins among thousands of others in complex mixtures. Second, we constructed protein-polymer conjugates using 2-pyridinecarboxaldehyde reaction for intracellular protein delivery. The polymers were endowed with 2-pyridinecarboxaldehyde (2PCA) groups, which modify proteins selectively at their N-terminal positions through imidazolidinone formation. The polymer-modified proteins were delivered into the cytosolic compartment of various cancer cells and the function of the proteins was retained during the process. Importantly, mechanistic studies have revealed that the internalization pathways of the constructs are likely to occur through a membrane fusion mechanism, thus at least partially circumventing the protein inactivation that occurs through endocytosis. Finally, we adapted 2PCA and oxidative coupling reactions to create a Förster resonance energy transfer construct of an intrinsically disordered protein (IDP) to monitor protein folding. A library of IDP with different lengths and densities of polyethylene glycol (PEG) through lysine modifications was constructed. We demonstrated that the size and density of the PEG chains had little to no effect on the conformation of IDPs

Short and long-term effects of exposure to low dose and low dose rate of gamma radiation : using in vitro and in vivo models

Assessment of human health risks from exposure to ionizing radiation (IR) is mainly based on the extrapolation of results from epidemiological studies on populations exposed to relatively high doses and often at high dose rates (HDR). Risk estimates after exposure to low doses and in particular at low dose rates (LDR) remain controversial due to a lack of epidemiological evidence. Therefore, high priority is given to strengthening the evidence on which risk assessments can be based for low doses and LDR. It is known that the cytotoxicity of radiation decreases by decreasing dose rate. Less is known about the effects of LDR on mutation rates and premature senescence compared to HDR. We established 2 cell lines with low expression of two proteins, MTH1 or MYH, both involved in the protection of cells from mutation induction by reactive oxygen species (ROS). The cells were exposed to different doses at different dose rates, and the levels of mutation were studied. The results showed a possible dose-rate threshold for mutations for the MTH1/MYH double knockdown cells. Next, we studied the effect of dose rate on adaptive response (AR). AR is defined as the ability of a low dose of ionizing radiation to induce enhanced resistance in cells subsequently exposed to a high dose. We established dose response relations for survival and mutations for MCF-10A cells exposed/non-exposed to an adaptive dose of 50 mGy at different dose rates, followed by exposure to different high doses. We found no protective effect of 50 mGy on survival. However, we observed that 50 mGy the adaptive dose reduced the mutation frequency induced by 1 Gy challenging dose. The protection level was higher when 50 mGy was delivered at LDR. A significant amount of data suggests that oxidative stress, induced for example by LDR, can contribute to senescence. We cultured VH10 cells, beginning with passage 13, during chronic LDR exposure. The cells were passaged every week for 6 weeks until they stopped proliferating due to premature senescence at passage 19. Passage 8 VH10 cells were cultured correspondingly but without irradiation until they stopped proliferating at passage 23 in response to replicative senescence. The DNA repair kinetics and the levels of DNA damage that were localized in the telomeres of young, middle-aged, premature senescent and replicative senescent cells were investigated. The young cells repaired DSB significantly faster than the senescent cells; premature and replicative senescent cells accumulated more DNA damage in the telomeres; and as compared to middle-aged cells, young cells cope with oxidative stress of chronic irradiation more effectively. The transgenerational effects of IR were studied in Drosophila embryos. The exposed embryos were followed up for abnormality during embryogenesis until adult stage and up to 12 generations. We found that radiation induced an A5pig- phenotype (depigmented area in the A5 segment of the male body) that was transmitted up to 12 generations. This phenomenon did not follow the Mendelian inheritance model, which indicates the influence of mechanisms other than mutagenesis e.g. epigenetic mechanism. We showed that; LDR is less cytotoxic than HDR but both induce equal levels of mutation per unit dose; LDR induces premature senescence; LDR may be more effective than HDR in inducing adaptive response; and LDR and HDR exposure of Drosophila embryos can induce an abnormal phenotype that can be transmitted through generations