表面プラズモン顕微鏡法による異方性媒質の特性評価

本研究では，光学的異方性を有する薄膜試料の顕微分析を可能とするナノプローブの開発を行い，これを用いて10-3 ~ 10-1 の範囲で複屈折を測定することに成功した. 開発したプローブでは集束表面プラズモン（高開口数の顕微鏡対物レンズを用いて集束させた光で励起した表面プラズモン）を利用しており，集束表面プラズモンの空間周波数応答から複屈折の測定を行う．具体的には，試料の複屈折によって，反射光空間周波数分布に生じる楕円状の光吸収パターンの方位と楕円率から，複屈折の大きさと光学軸の方位を求める．このプローブは，従来法に比べ極めて微小な領域における試料の複屈折を測定することができる．はじめに，この手法の妥当性を検証するため，光誘起複屈折を示す薄膜異方性試料の複屈折の大きさと進相軸の方位を，さまざまな条件下で測定した．実験では，アゾ系高分子（PAZO: poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzene-sulfonamide]-1,2- ethanediyl sodium salt]）スピンコート薄膜を作製し，紫外光照射が引き起こすシス型からトランス型への遷移がもたらす複屈折を調べた．その結果，0.01 ~ 0.07の範囲で変化することを測定することができた．また，さまざまな偏向状態の紫外光を照射したときに，反射光の空間周波数分布に生じる楕円状の光吸収パターンの回転から，進相軸の方位の変化を確認することができた. また，大きな複屈折を示す試料の測定におけるプローブの適用性を確認するために，巨大複屈折を示すアゾ系高分子を合成し，これを薄膜化した試料の複屈折を測定し，その結果と従来からの偏光解析手法による測定結果との相関を確認した．さらに，開発したプローブを生体試料の微小複屈折測定に応用する検討を行った．ここでは，ニワトリの表皮や真皮など皮膚のさまざまな部位の複屈折測定を行い，表皮では ~ 0.008 ，真皮では ~ 0.03 の複屈折を示すことを確認した．また，この測定から，皮膚組織がもたらす強い光散乱も無視できることを確認できた．これによって，無標識でさまざまな病理診断が行える潜在性を示すことができ，たとえば，紫外光環境下での繊維芽細胞の複屈折を測定することで，皮膚日射病を診断できると考える．In this thesis, I have developed a nano-probe for the microscopic characterization of anisotropic samples specially in the form of thin films. The developed probe has been successfully tested to measure birefringence in the range of 10-3 ~ 10-1. The probe was developed with focused surface plasmon (interference of surface plasmons generated by coupling with convergent incident light from a high numerical aperture microscope objective). The birefringence of the sample caused the change in the propagation constant along the principal directions of the sample. Elliptical absorption pattern in the reflected spatial frequency distribution was observed on introduction of anisotropic sample as Kretschmann configuration. The ratio of the propagation constants along the principal directions yields the magnitude of birefringence while the orientation of the elliptical absorption pattern in the reflected spatial distribution denotes the fast axis of the sample. The developed probe is thus able to quantitatively characterize anisotropicity of samples in microscopic region. The detailed characteristics of the anisotropic samples in the form of thin films exhibiting photo-induced birefringence have been analyzed in terms of the magnitude of birefringence and the direction of fast axis. I examined azo-polymer PAZO poly[1-[4-(3-carboxy-4-hydroxyphenylazo) benzene-sulfonamide]-1,2-ethanediyl sodium salt] thin films produced by spin coating. The birefringence varies in the range of 0.01 - 0.07 with low density under the influence of ultra-violet radiation due to photo-isomerization (transition from the cis-state to the trans-state). The fast axis of the sample could be rotated with the change in polarization of the ultra-violet light. This could be further correlated with the change in orientation of elliptical absorption pattern at the reflected spatial frequency distribution. Further, to perform high birefringence measurement with the developed probe, I also synthesized gigantic birefringence azo-polymer (exhibiting photo-induced birefringence: Δn ∼ 0.4). I correlated the results with simple in-line polarimetric set-up. Also, I checked the applicability of the developed probe for determining very low birefringence of bio-samples. I analyzed various parts of the chicken skin samples like the epidermal and the dermal layers to observe the birefringence changes. It was found that the dermal layer of the skin showed Δn ∼ 0.03 while that of the epidermis showed Δn ∼ 0.008. Further I confirmed that the effect of scattering on near-field anisotropic characterization is negligible. Thus, this method can be used to characterize highly scattering samples like skin. I believe that the developed probe can find potential application towards disease detection, as most tissues within human body secrete collagen (possessing intrinsic birefringence). The increase of birefringence in such tissues can be used as a label free bio-marker. Potential example include detection of dermatoheliosis from the change in the quantitative birefringence of the fibroblasts in the ultra-violet environment.室蘭工業大学 (Muroran Institute of Technology)博士（工学）当アイテムは要旨のみの公開になっています（2021-12-9

Coping the arsenic toxicity in rice plant with magnesium addendum for alluvial soil of indo-gangetic Bengal, India

Arsenic (As3+) is a toxic metalloid found in the earth’s crust, its elevated concentration is a concern for human health because rice is the staple grain in eastern part of India and the waterlogged rice field environment provides opportunity for more As3+ uptake. Magnesium (Mg2+) is an important plant nutrient. Present work is a search for reducing As3+ toxicity in plants through Mg2+ application. The findings are quite impressive, the root to shoot biomass ratio showed more than 1.5 times increase compared to the control. Total protein content increased 2 folds. Carbohydrate and chlorophyll content increased two to three times compared to control. On the other hand, Malondialdehyde content showed a decline with the application of increased Mg2+ dose. The in-silico study shows a better interaction with As3+ in presence of Mg2+ but interestingly without stress symptoms. These findings from the research indicate that Mg2+ application can be effective in reducing As3+ induced stress in plants

Characterization of cellophane birefringence due to uniaxial strain by focused surface plasmon microscopy

In this paper, we study the relationship of local birefringence and stress oriented inhomogeneous elasticity of a sample from the spatial frequency response of focused surface plasmon (FSP). The birefringence of the sample varies the propagation constant of surface plasmon with regard to its direction and produces an elliptic absorption pattern in the reflected spatial frequency distribution. Birefringence is calculated from the ratio of the propagation constant along the fast to slow axis of the sample. The change in eccentricity was proportional to the applied stress on cellophane film. A strong correlation (0.94∼0.97) exists between FSP and phase shifting interferometry results

Dataset on the development of palladium nanoparticle decorated colloidal porous organic polymer for photocatalytic Suzuki coupling

Herein, we report the synthesis and characterization data of visible-light-active colloidal azobenzene-based porous organic polymer (Azo–POP) and its Pd-nanoparticle loaded analog (Pd–Azo–POP). The setup for photocatalytic Suzuki reactions triggered by Pd–Azo–POP under conventional batch reaction mode as well as in a prototypal continuous flow system has also been provided in addition to the detailed catalytic data including 1H and 13C NMR spectra of the obtained products. For further discussions on the materials, their effect on overall catalysis and mechanistic insight, please refer to the associated article “Pd-nanoparticle decorated azobenzene-based colloidal porous organic polymer for visible and natural sunlight-induced Mott–Schottky junction mediated instantaneous Suzuki coupling” (Chakraborty et al., 2019)

Metal organic frameworks mimicking natural enzymes : a structural and functional analogy

In this review, we have portrayed the structure, synthesis and applications of a variety of biomimetic MOFs from an unprecedented angle. Synthetic MOF analogues of five distinct enzymes: phosphotriesterase, hydrogenase, cytochrome P450, chymotrypsin and carbonic anhydrase, have been discussed with their skeletal comparison to actual enzymatic active sites as reference, and an explanation of catalytic pathways from the mechanistic cycle of the corresponding enzymes is depicted. We demonstrated critically each of the five discrete situations by assimilating available benchmark researches in an attempt to provide a concise literature source on the ingenious design strategies and versatile biomimetic applications of this domain of materials

Antagonistic and synergistic effects of lead and selenium in Rattus norvegicus

Female rats were administered intraperitoneal injections of solutions of lead acetate and sodium selenite. The salt solutions were given singly to 'control' animals and successively to the 'treated' animals in both chronic and acute treatments but with or without a time gap of 1 h in the latter treatment. In the chronic treatments the dosage of lead acetate was kept constant and that of sodium selenite varied while in the acute treatments the ratio of the two salts was kept constant. Degrees of protection afforded by sodium selenite against chromosomal damage caused by lead acetate were assessed