Microplastic (MP) and nanoplastic (NP) induce neurotoxicity, cytotoxicity, and reproductive system toxicity in mammals. However, the impacts of NPs on the endocrine system are obscure. Here, monodisperse polystyrene nanoplastics (PS-NPs) were prepared by emulsion polymerization and the accumulation of fluorescent PS-NPs in various organs, including the liver, kidney, spleen, and pancreas, was examined. The oral administration of PS-NPs induced visceral organ injury, and the main toxicities were damage to hepatic function and the abnormity of lipid metabolism. Global transcriptome sequencing (RNA-Seq) revealed the impact of PS-NPs on the genes involved in reactive oxygen species (ROS) generation and the PI3K/Akt signaling pathway, which is associated with glucose metabolism in mice. Chronic exposure to PS-NPs significantly increased plasma glucose levels and ROS levels, but did not affect plasma insulin secretion. The phosphorylation of insulin receptor substrate (IRS)-1 at Ser307 was raised, which decreased the phosphorylation of Akt (at Ser473) in the PI3K/Akt pathway. Collectively, these findings suggested that the oral administration of PS-NPs significantly increased ROS, hepatic triglycerides, and cholesterol accumulation. The high levels of ROS disturbed the PI3K/Akt pathway, causing insulin resistance and increased plasma glucose in the mouse liver.

Titanium dioxide nanoparticles (TiO2 NPs) are authorized food additives, and children have the highest exposure. Therefore, children are likely more susceptible to the adverse effects of TiO2 NPs than adults. Previous study showed that oral administration of 50 mg/kg body weight (bw) TiO2 NPs increase plasma glucose in mice. However, few studies have directly compared the adverse effects of exposure to TiO2 NPs on plasma glucose metabolism of different age groups. In this study, the developing (age 3 weeks) and adult mice (age 10 weeks) were orally administered with 50 mg/kg bw TiO2 NPs per day. The TiO2 NPs induced hyperglycemia earlier in the developing mice than in the adult mice. Then mechanisms were analyzed after mice were oral administration of TiO2 NPs for 8 weeks and 26 weeks, respectively. Results showed that the treatment with TiO2 NPs activated xenobiotic biodegradation in livers of both developing and adult mice at the early stage. However, only in the developing mice, TiO2 NPs induced endoplasmic reticulum (ER) stress in livers and increased reactive oxygen species in livers and sera in the early stage. The ER stress and ROS activated an inflammation response and mitogen-activated protein kinase pathways, thereby inducing insulin resistance in the livers of developing mice at the early stage. The response of the adult mice was delayed, and these changes were observed in the late stage of the study. The results of this study all suggest that children are more susceptible than adults to the toxicity of orally administered TiO2 NPs.

Titanium dioxide nanoparticles (TiO2 NPs) are reported to increase plasma glucose levels in mice at specific doses. The production and accumulation of reactive oxygen species (ROS) is potentially the most important factor underlying the biological toxicity of TiO2 NPs but the underlying mechanisms are unclear at present. Data from genome-wide analyses showed that TiO2 NPs induce endoplasmic reticulum (ER) stress and ROS generation, leading to the inference that TiO2 NP-induced ER stress contributes to enhancement of ROS in mice. Resveratrol (Res) effectively relieved TiO2 NP-induced ER stress and ROS generation by ameliorating expression of a common set of activated genes for both processes, signifying that ER stress and ROS are closely related. TiO2 NP-induced ER stress occurred earlier than ROS generation. Upon treatment with 4-phenylbutyric acid to relieve ER stress, plasma glucose levels tended toward normal and TiO2 NP increased ROS production was inhibited. These results suggest that TiO2 NP-induced ER stress promotes the generation of ROS, in turn, triggering increased plasma glucose levels in mice. In addition, Res that displays the ability to reduce ER stress presents a dietary polyphenol antioxidant that can effectively prevent the toxicological effects of TiO2 NPs on plasma glucose metabolism.

Titanium dioxide nanoparticles (TiO2NPs) constitute the top five NPs in use today. In this study, oral administration of 50, 100, and 200 mg/kg body weight (b.w.) TiO2NPs increases plasma glucose in mice, whereas 10 and 20 mg/kg b.w. TiO2NPs did not. RNA sequencing (RNA-seq) technology was used to investigate genome-wide effects of TiO2NPs. Clustering analysis of the RNA-seq data showed the most significantly enriched gene ontology terms and KEGG pathways related to the endoplasmic reticulum (ER) and ER stress. Molecular biology verification showed that 50 mg/kg b.w. and higher doses TiO2NPs activated a xenobiotic biodegradation response and increased expression of cytochrome P450 family genes in mouse livers, thus inducing ER stress in mice. ER stress-activated MAPK and NF-κB pathways and induced an inflammation response, resulting in phosphorylation of the insulin receptor substrate 1 and, consequently, insulin resistance. This was the main mechanism by which TiO2NPs increased plasma glucose in mice. Meanwhile, ER stress disturbed the monooxygenase system, and thus generated reactive oxygen species (ROS). Relief of ER stress with 4-phenylbutyric acid inhibited all the above effects of TiO2NPs, including the generation of ROS. Therefore, TiO2NP-induced ER stress was a decisive factor with a central role in plasma glucose disturbance in mice.

Adiponectin, an adipocytokine produced by adipocytes, functions as an anti-inflammatory and anti-apoptotic substance, while also enhancing insulin sensitivity. Patients or model animals with obesity or diabetes typically present attenuated expression of adiponectin. Moreover, obesity and diabetes are often accompanied with hypoxia in adipose tissue, which may result in endoplasmic reticulum (ER) stress as well as low expression of adiponectin. The purpose of this study was to investigate the specific role of the unfolded protein response (UPR) involved in the low expression of adiponectin induced by hypoxia. Subjecting 3T3-L1 adipocytes to hypoxia significantly reduced adiponectin expression and activated the PERK and IRE1 signaling pathways in a time-dependent manner. The ATF6 signaling pathway showed no obvious changes with hypoxia treatment under a similar time course. Moreover, the down-regulated expression of adiponectin induced by hypoxia was relieved once the PERK and IRE1 signaling pathways were suppressed by the inhibitors GSK2656157 and 4μ8C, respectively. Overall, these data demonstrate that hypoxia can suppress adiponectin expression and activate the PERK and IRE1 signaling pathways in differentiated adipocytes, and this two pathways are involved in the suppression of adiponectin expression induced by hypoxia.

Zinc sulfide (ZnS) films were successfully grown by using mist chemical vapor deposition (mist-CVD) with fine-channel susceptor made of quartz. For the investigation of growth dynamics, two types of mist generators and two types of susceptors were prepared and distribution profiles of film thickness were examined. Thermal efficiency of susceptor depends on heat-penetration efficiency and line-velocity of the mists, which are influenced by the fine-channel gap-height of the susceptors. Using larger size of mists requires higher thermal efficiency in susceptor to obtain a flat thickness distribution. This result indicates that the optimization of the mist size and the susceptor structure is important for the film uniformity of grown films by the mist-CVD. (C) 201 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Musclin is a type of muscle-secreted cytokine and its increased gene expression induces insulin resistance in type 2 diabetes. However, the mechanism underlying increased musclin gene expression is currently unclear. Excessive saturated fatty acids (SFA) can activate the secretion of several muscle-secreted cytokines as well as endoplasmic reticulum (ER) stress pathway, thereby contributing to the development of type 2 diabetes. The purpose of this study was to investigate the mechanisms responsible for the effect of palmitate, the most abundant SFA in the plasma, on the gene expression of musclin in C2C12 myotubes. Treatment of C2C12 myotubes with palmitate or tunicamycin significantly increased the expression of musclin as well as ER stress-related genes, but treatment with oleate did not. Pre-treatment of C2C12 myotubes with 4-phenyl butyrate suppressed the expression of ER stress-related genes, simultaneously, resulting in decreased expression of the musclin gene induced by palmitate or tunicamycin. These results indicate that ER stress is related to palmitate-induced musclin gene expression. Moreover, palmitate-induced musclin gene expression was significantly inhibited in C2C12 myotubes when PERK pathway signaling was suppressed by knockdown of the PERK gene or treatment with GSK2656157, a PERK autophosphorylation inhibitor. However, there was no difference in the palmitate-induced musclin gene expression when IRE1 and ATF6 signaling pathways were suppressed by knockdown of the IRE1 and ATF6 genes. These findings suggest that palmitate increases musclin gene expression via the activation of the PERK signaling pathway in C2C12 myotubes.

The mist chemical vapor deposition (mist CVD) method, which uses ultrasonically atomized solutions as sources, is an environmental friendly and cost-effective technology for the growth of compound semiconductors. This growth process is realized under atmospheric pressure and allows us to use many kinds of salts, complexes, and compounds with low toxicity for sources. Using the oxidizability of water including the source, most of the previous reports of the mist-CVD method are on oxide materials. In this study, we fabricated zinc sulfide (ZnS) films by mist-CVD method using thiourea-based water solutions as sources. Investigating the growth of ZnS by mist-CVD under various growth conditions and experimental setups, we proposed zinc-chloride complexes are necessary for the growth of ZnS and vaporized mist sources act as precursors.

Background:The chemical chaperone 4-phenylbutyric acid (4-PBA) has been shown to relieve endoplasmic reticulum (ER) stress. Therefore, it improves insulin sensitivity and promotes glucose metabolism in skeletal muscle. Glucose transporter type 4 (GLUT4), as a major glucose transporter protein, plays a central role in glucose metabolism. Until now, it has been unclear whether 4-PBA affects GLUT4 gene expression and thus, contributes to glucose metabolism. Methods: C2C12 myotubes were treated with 4-PBA, tunicamycin or butyrate and subjected to Western blot and RT-PCR. Results: 4-PBA-treated C2C12 myotubes increased GLUT4 expression and promoted glucose metabolism. Most interestingly, GLUT4 gene expression induced by 4-PBA was not associated with ER stress even in the presence of tunicamycin, an ER stress inducer. Moreover, we also found that 4-PBA inhibited histonedeacetylase 5 (HDAC5) expression in C2C12 myotubes, resulting in hyperacetylation of the histone H3 at the myocyte enhancer factor 2 (MEF2) binding site. This increased the binding of MEF2A to the site on the GLUT4 promoter, resulting in increased GLUT4 expression. Conclusions: Our data indicate that 4-PBA increases GLUT4 expression by acetylating the MEF2 site to increase the MEF2A binding through a mechanism that involves suppression of the HDAC5 pathway, but without involving ER stress. Copyright (C) 2014 S Karger AG, Basel

We carried out laser ablation of three organic molecules, rubrene (Rb), Oralith Brilliant Pink R (BP) and quinacridonequinone (QQ) in a poor solvent, water. As a result, nanoparticles of BP and QQ were formed, but those of Rb were not formed because of photodissociation. For a rigid molecule, QQ, optical properties of colloidal solutions were investigated in relation to the size of the included nanoparticles. A linear correlation between the blue shift of the absorption peak energy and the decrease in the diameter of the nanoparticles was found, indicating that the nanoparticle diameter can be easily estimated from the absorption spectrum of a colloidal solution. From the solution, a nanoparticle film was fabricated on an electrode by the electrophoretic deposition method. © 2012 Materials Research Society.

We report on generation of coherent terahertz radiation by photomixing with a photoconductive antenna placed in a three-dimensional photonic crystal cavity. We observed efficiency peaks around the frequencies near the photonic bandedges and at the planar defect modes. The efficiency peaks observed near the photonic bandedges are associated with the increase of the optical mode density at the bandedge. The relatively low efficiency at the planar defect mode frequencies are explained by the mode diffusion in the lateral direction of the defect layer.

We report on the radiation power of the terahertz (THz) beam from YBa2Cu3O7-delta (YBCO) thin film antennas. InSb hot-electron bolometer is used to estimate the radiation power after being calibrated in the THz beam generation and detection system. The 100-nm-thick and 30-mum-wide YBCO thin film bridges are connected to a self-complimentary log-periodic toothed planar antenna or a bow-tie antenna. Femtosecond optical pulses are focused onto the center bridge of the antennas being biased with a current up to 1 A. The detected power increases in proportion with increasing bias current, and reaches over 22 muW in the average at an excitation power of 98 mW. (C) 2001 Elsevier Science BY. All rights reserved.

Terahertz (THz) radiation is generated by exciting an un-doped InAs wafer with a femtosecond free-electron laser (FEL) at the Thomas Jefferson National Accelerator Facility. A microwatt level of THz radiation is detected from the unbiased InAs emitter when it is excited with the femtosecond FEL pulses operated at a wavelength of 1.06 mum and 10 W average power.

Ultrabroadband detection of terahertz radiation is demonstrated with a low-temperature-grown GaAs photoconductive antenna gated with 15-fs laser pulses. The observed spectra extends up to 20 THz and shows an absorption band between 7 similar to 10 THz due to the phonon resonance in GaAs substrate of the detector.

We demonstrate generation of coherent. terahertz radiation by photomixing with a photoconductive antenna placed in a 3-D photonic crystal cavity. We observe a sharp gain peak at a frequency in the photonic bandgap, suggesting a cavity effect for it localized defect mode.

We report the ultrafast impulsive excitation of coherent LO phonons with the frequency of 5.57 THz in InSb. These phonons, when generated by femtosecond laser pulses. exhibit phase-dependent fluctuation properties. that is, the variance of coherent amplitude is a function of time delay. The variance oscillations occur, for short time delays, at twice the frequency of the coherent amplitude. (C) 2000 Elsevier Science B.V. All rights reserved.

We report on the ultrabroadband coherent detection of radiation in wavelengths spanning from far to midinfrared with a low-temperature-grown GaAs photoconductive dipole antenna gated with 15 fs light pulses. The detected spectral frequency exceeds 20 THz. (C) 2000 American Institute of Physics. [S0003-6951(00)05451-6].

The azimuthal angle dependence and the temperature dependence of terahertz (THz) radiation generated from n-type (111) InSb and n-type (111) InAs surfaces irradiated with similar to 80 fs near-infrared laser pulses are investigated. The azimuthal angle dependence shows that the contribution of the difference-frequency mixing (DFM) is not dominant for both materials at the excitation density of similar to 1 GW/cm(2). At an appropriate azimuthal angle, the radiation due to DFM is excluded from the total THz radiation and the temperature dependence of THz radiation due to the surge current is observed. The increase of THz radiation with decrease of the temperature is found to be much more pronounced for InSb than for InAs. The different temperature dependence can be attributed to the different radiation mechanisms dominant for both materials. Especially, the temperature dependence of the THz radiation from InSb is well explained by the photoDember effect.

We have reviewed and discussed the generation of continuous-wave terahertz radiation by the photomixing of dual-mode lasers, which includes a multi-mode laser diode (LD), a dual-mode microchip laser, a monolithic dual-mode DBR LD, and a widely tunable dual-mode external cavity LD. It is demonstrated by several experiments that the beat frequency of a dual-mode laser is more stable than the original laser modes because of the common-mode rejection effect. We also suggest a novel scheme by which the optical beat is stabilized to less than 1 kHz and its frequency can be precisely determined as well.

Coherent cw-terahertz (THz) radiation has been generated by photomixing with a photoconductive antenna fabricated on a low-temperature-grown (LTG) GaAs film using a two-longitudinal-mode distributed Bragg reflector (DBR) laser diode (LD). The frequency of the emitted radiation corresponds to the difference frequency between the two modes of the LD. The linewidth of the radiation is much narrower than that of each laser mode oscillating in the same cavity due to the common-mode rejection effect between the two modes oscillating in the same cavity. This property of the two-mode LD, as well as its compactness and ease of optical alignment, make the device promising as an excitation laser source for photomixing.

A tunable dual-wavelength external cavity laser diode (2-lambda-ECL) was used to generate tunable coherent cw-terahertz (THz) radiation by photomixing in a biased photoconductive antenna fabricated on a low-temperature-grown (LTG)-GaAs film. The 2-lambda-ECL oscillated at the two output modes simultaneously with a frequency separation from 250 GHz to 2.1 THz in the same cavity. We demonstrated that the frequency of the emitted THz radiation corresponded to the difference frequency between the two modes of the diode laser. The tunable 2-lambda-ECL, due to its compact design and ease of optical alignment, is a promising laser source for the generation of tunable cw-THz radiation by photomixing.

講演講師等

講師,任期:2019年12月～

国際交流事業

ナノ粒子の応用検討,相手国:中国

公開講座・講演会の企画・講師等

LEDと豆電球について,日付:12月

講演講師等

講師,任期:2018年12月～

国際交流事業

全体会議での大学の紹介及び個別進学相談

国際交流事業

ナノ粒子の応用検討,相手国:中国

公開講座・講演会の企画・講師等

LEDと豆電球について,日付:12月

講演講師等

講師,任期:2017年１１月～

国際交流事業

理事

国際交流事業

ナノ粒子の応用検討,相手国:中国

国際交流事業

全体会議での大学の紹介及び個別進学相談

公開講座・講演会の企画・講師等

半導体LEDについて講習会,日付:10月

小・中・高校生を対象とした学部体験入学・出張講座等

監査,日付:11月

国際交流事業

ナノ粒子の応用検討,相手国:中国

小・中・高校生を対象とした学部体験入学・出張講座等

実行委員長,日付:11月

国際交流事業

ナノ粒子の応用検討,相手国:中国

小・中・高校生を対象とした学部体験入学・出張講座等

実行委員会の事務局長,日付:11月

国際交流事業

ナノ粒子の応用検討,相手国:中国

公開講座・講演会の企画・講師等

高校理科教師の研究活動について助言,日付:12月

公開講座・講演会の企画・講師等

半導体LEDについて講習会,日付:10月

国際交流事業

ナノ粒子の応用検討,相手国:中国

公開講座・講演会の企画・講師等

ペットボトルロケット打ち上げ大会

小・中・高校生を対象とした学部体験入学・出張講座等

「缶サット」とラジコン飛行機の研究

国際交流事業

ナノ粒子の応用検討,相手国:中国

小・中・高校生を対象とした学部体験入学・出張講座等

「缶サット」とラジコン飛行機の研究

公開講座・講演会の企画・講師等

ペットボトルロケット打ち上げ大会

国際交流事業

ナノ粒子の応用検討,相手国:中国

公開講座・講演会の企画・講師等

附属校・公立学校との連携事業

公開講座・講演会の企画・講師等

ペットボトルロケット打ち上げ大会

国際交流事業

ナノ粒子の応用検討,相手国:中国

小・中・高校生を対象とした学部体験入学・出張講座等

「缶サット」とラジコン飛行機の研究

学術雑誌等の編集委員・査読・審査員等

編集委員,任期:H21-22

国際交流事業

テラヘルツ電磁波の応用分野探求,相手国:中国

小・中・高校生を対象とした学部体験入学・出張講座等

「缶サット」打ち上げをテーマにした高大連携教育

国際交流事業

国際会議の招待参加,相手国:中国

国際交流事業

実験設備の立ち上げの助言,相手国:中国

小・中・高校生を対象とした学部体験入学・出張講座等

出張授業

小・中・高校生を対象とした学部体験入学・出張講座等

体験授業

国際交流事業

共同研究の組織の立ち上げ,相手国:中国

公開講座・講演会の企画・講師等

実験体験

小・中・高校生を対象とした学部体験入学・出張講座等

体験授業

公開講座・講演会の企画・講師等

実験・観察・工作

小・中・高校生を対象とした学部体験入学・出張講座等

出張授業

国や地方自治体、他大学・研究機関等での委員

理事,任期:2017年７月～2019年

学協会、政府、自治体等の公的委員

学協会、政府、自治体等の公的委員,任期:2

国や地方自治体、他大学・研究機関等での委員

教育担当,任期:2年

ボランティア活動等

中国語担当

社会との連携を推進する活動

実行委員長

ボランティア活動等

中国語担当

社会との連携を推進する活動

実行委員会の事務局長

ボランティア活動等

中国語担当

ボランティア活動等

中国語担当理事

ボランティア活動等

通訳担当理事

ボランティア活動等

通訳担当理事

ボランティア活動等

教育策担当

ボランティア活動等

教育策担当

産業界、行政諸機関等と行った共同研究、新技術創出、コンサルティング等

株式会社ABsizeとナノ粒子の作製の研究,実施者:和歌山大学　

産業界、行政諸機関等と行った共同研究、新技術創出、コンサルティング等

株式会社ABsizeとナノ粒子の作製の研究,実施者:和歌山大学