Topological Mechanism of Nucleation of Cyclic Polyethylene(Knots and soft-matter physics: Topology of polymers and related topics in physics, mathematics and biology)

この論文は国立情報学研究所の電子図書館事業により電子化されました。In order to clarify the effects of entanglement species on nucleation of polymers, we studied the nucleation rate I of cyclic and linear polyethylenes (C-PE and L-PE) from the melt as a function of degree of supercooling ΔT by means of polarizing optical microscope. We prepared several C-PEs with different weight average molecular weights M_w=4600-114800. I of all the sample were obeyed the equation, I=I_0exp(-C/ΔT^2). I_0s of C-PE with M_w=114800 and L-PE with M_w=35400 were almost the same. This indicates that C-PE is easier to nucleate than L-PE due to lack of knot entanglements. On the other hand, Cs for C-PE significantly increased with increasing M_w. This tendency is quite different with L-PE previously reported. The increase of C indicates that folding regularity of end surface of nucleus increases. Since topological constraint of C-PE arose from the lack of chain ends is relatively decreased with increasing M_w, it was implied that the nucleation behavior of C-PE approaches that of L-PE

Basic performance assessment of reagents for measuring soluble FMS-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF) in Japanese women

Among the factors associated with angiogenesis, soluble FMS-like tyrosine kinase-1 (sFlt-1) is antiangiogenic and placental growth factor (PlGF) is proangiogenic. The sFlt-1/PlGF ratio is considered useful for the short-term prediction of preeclampsia (PE) in high-risk pregnancies and has been used clinically in Japan since July 2021. Regarding the clinical use of the sFlt-1/PlGF ratio in Japan, there have been no published reports demonstrating that sFlt-1 and PlGF assay reagents have the same basic performance in Japanese and European women. To our knowledge, we conducted the first basic performance assessment of the sFlt-1 and PlGF assay reagents using sera from Japanese women. We obtained satisfactory results for repeatability, intermediate precision, linearity, effects of interferents, and the LoQ. The sFlt-1 and PlGF assay reagents performed well, and we believe that they are entirely adequate for use in routine clinical assays of Japanese patients, similar to those in European patients

Efficient Chain Extension Reaction of Poly (butylene terephthalate) by using Crystallization

Plastics are quite important materials for not only industrial usages but also our daily life. Many plastics are difficult to reuse because they are susceptible to UV, hydrolysis and so on leading to the reduction of molecular weight. Among them, poly (butylenes terephthalate) (PBT) is a valuable materials prepared by polycondensation reaction, and PBT has the same limitation to reuse. Hence, efficient chain extension reaction for recovered PBT has been needed to improve the properties damaged by chain scission. In this study, new chain extension reaction had been examined by using crystallization as pre-treatment. Isothermal crystallization at 161℃ concentrated the chain end-groups on the surface of the crystals, and chain extension reaction at 210℃, which was lower than the melting temperature of PBT, enhanced the molecular weight significantly compared with the reaction over the melting temperature. It concluded that the pre-treatment of crystallization was favorable for the efficient chain extension reaction and this result provided the new technology for the effective reuse of the plastics

Effect of the blend ratio of cyclic and linear polyethylene blends on isothermal crystallization in the quiescent state

The role of entanglements that form between cyclic and linear polymers in crystallization is of particular interest, but it is not fully understood. We investigated the crystallization behaviors of blends of cyclic polyethylene (C-PE) and linear polyethylene (L-PE) in a quiescent state to elucidate the role of this novel entanglement in crystallization. The samples were prepared by mixing the prepared C-PE and L-PE specimens at L-PE weight fraction (ΦL-PE) values of 0–100 wt%, with the weight average molecular weights of C-PE and L-PE being 175 × 103 and 154 × 103, respectively. The isothermal crystallization behaviors were analyzed through polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The morphology observed through POM was similar to that of ΦL-PE. From the time evolution of the heat flow measured via DSC, we obtained the half-crystallization time (t1/2) values as functions of ΦL-PE at different degrees of supercooling (ΔT). The 1/t1/2 values of the C-PE and L-PE homopolymers were approximately the same at ΔT = 25.5 and 26.5 K. At a larger ΔT value, the 1/t1/2 value of C-PE was significantly larger than that of L-PE. In contrast, 1/t1/2 reached a minimum value at ΦL-PE = 30–40 wt%, irrespective of ΔT. As the entanglement density increased with increasing ΦL-PE, the crystallization rate was expected to decrease monotonically. By considering the experimental relationship between 1/t1/2 and ΦL-PE, we speculated that the suppression of crystallization in the blended system was caused by a novel entanglement formed by the penetration of the L-PE chain into the C-PE chain

The job description survey for analyzing experiences, knowledge and skills of institutional researcher in the U.S. higher education institutions

我が国において近年進む大学改革の中で，大学職員の高度専門職化は一つの重要課題となっている。特に，18歳人口減少社会を迎え，厳しい大学運営を迫られる現状においては，経営資源の有効化や，的確な大学経営判断が欠かせなくなっている。そのような中，データ分析や経営判断のための情報を集めるInstitutional Research(IR)は，様々な職種の中でも大きな注目を集めている。すでに，日本の一部大学にも広がっているが，必ずしもその形は一様でなく，全体的な定着に至るにはまだ課題もある。本論では，IRを早くから導入し，高度専門職化を進めてきたアメリカの事例から，大規模な大学の教職員の公募サイトであるHigherEdJobsを利用し，客観的な情報からIRを適切に運用するために求められる経験や能力を考察する。Professional development for the college and university’s staff is to be one of the vital issues in the recent university reform movement in Japan. Japanese higher education institutions face unfavorable financial conditions due to the decreasing 18 years old population. That make colleges and universities having management perspective for utilizing managerial resources and appropriate descion making in their management. Institutional Research (IR) is seen important work in the university administration and penetrate to Japanese higher education gradually. This study aim to point out the experiences, knowledge and skills of Institutional researcher through analyzing job description on recruiting website in U.S. as an advance case of IR

Selective cyclooxygenase-2 inhibitors show a differential ability to inhibit proliferation and induce apoptosis of colon adenocarcinoma cells

AbstractAlthough the influence of selective cyclooxygenase (COX)-2 inhibitors on the proliferation of colon adenocarcinoma cells have been the subject of much investigation, relatively little research has compared the effects of different COX-2 inhibitors. Celecoxib strongly suppressed the proliferation of COX-2 expressing HT-29 cells at 10–40 μM. NS-398 and nimesulide also inhibited cell proliferation, whereas rofecoxib, meloxicam, and etodolac did not. Only celecoxib induced apoptosis of HT-29 cells, as detected on the basis of DNA fragmentation, TUNEL positivity, and caspase-3/7 activation. DNA fragmentation was also increasd in COX-2 non-expressing cell lines (SW-480 and HCT-116) by exposure to celecoxib for 6–24 h. All six COX-2 inhibitors suppressed the production of prostaglandin E2 by HT-29 cells, suggesting that the pro-apoptotic effect of celecoxib was unrelated to inhibition of COX-2. Inactivation of Akt might explain the differential pro-apoptotic effect of these selective COX-2 inhibitors on colon adenocarcinoma cells

Evaluation of liver function for hepato-biliary-pancreatic surgery

In the present study, liver function at pre-operative and postoperative period was evaluated by various examinations. Patients with obstructive jaundice (n=14) and liver tumor (n=6) often have complications such as postoperative hepatic failure (n=4). They were divided into 3 groups: group A (n=7) had postoperative complications, group B (n=13) had uneventful postoperative course and group C (n=4) had postoperative hepatic failure. Liver function had significant correlations with levels of total bilirubin max (T-Bil max), hepaplastin tests (HPT) and ALPratio (post ope/pre-ope). Group C had T-Bil max≧30 mg/dl, HPT≦60% (54.4±14.7), ALPratio≧1.5, and admission ALP≧3000. We determined the level of bilirubin per day in drained blie (V-Bil) in 14 patients who underwent biliary drainage to ensure precise evalution of preoperative liver function. V-Bil was 332.9±140.0 mg/day on average, showing a close correlation with the serum bilirubin decreasing rate "b" and ICG R 15 (p<0.05). V-Bil is useful for evaluation of liver function in patients with malignant obstructive jaundice. In 6 patients without cirrhosis undergoing partial hepatectomy for liver tumor, ALPratio (≧1.5), a blood loss during operation (≧500), and operating time were related to the onset of postoperative hepatic failure

Triptolide, an active compound identified in a traditional Chinese herb, induces apoptosis of rheumatoid synovial fibroblasts

BACKGROUND: Extracts of Tripterygium wilfordii Hook F (TWHF), a traditional Chinese herb, have been reported to show efficacy in patients with rheumatoid arthritis (RA). Since RA is not only characterized by inflammation but also by synovial proliferation in the joints, we examined whether triptolide (a constituent of TWHF) could influence the proliferation of rheumatoid synovial fibroblasts (RSF) by induction of apoptosis. RESULTS: RSF were obtained from RA patients during surgery and were treated with triptolide under various conditions. The viability and proliferation of RSF were measured by the 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST-1) assay and by 5-bromo-2'-deoxyuridine incorporation, respectively. Apoptosis was identified by detection of DNA fragmentation using an enzyme-linked immunosorbent assay and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL). The role of caspases in apoptosis of RSF was analyzed by measuring caspase-3 activity. Activation of the peroxisome proliferator-activated receptor (PPAR) γ was assessed by a luciferase reporter gene assay using RSF transfected with a plasmid containing the peroxisome proliferator response element. Triptolide decreased viability, inhibited proliferation, and induced apoptosis of RSF in a concentration-dependent manner at very low (nM) concentrations. Caspase-3 activity was increased by treatment with triptolide and was suppressed by caspase inhibitors. Although PPARγ activation was induced by 15-deoxy-Δ(12,14)-prostaglandin J(2), triptolide did not induce it under the same experimental conditions. An extract of TWHF also induced DNA fragmentation in RSF. CONCLUSION: The mechanism of action remains to be studied; however, triptolide may possibly have a disease-modifying effect in patients with RA