31 research outputs found

    Synthesis, characterization, and its PL dynamics of colloidal type II CdTe/CdSe nanocrystals

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    We describe our improved synthesis and optical properties of high quality type II CdTe/CdSe nanocrystals (NCs). Specifically, clear shell-thickness dependences have been observed in the absorption and photoluminescence (PL) spectra and PL decay profiles as well. The magnitude of the lowest absorption band decreases drastically with large redshift as the shell thickness increases. The origin will be discussed on the bases of the model where the spatial configuration of the lowest electron-hole pair in the NCs changes from that of type I to type II as the shell thickness increases. As for the PL lifetime of the lowest electron-hole excitations, substantial increase is observed with increasing shell thickness. This can also be understood by considering the spatial configuration; spatial overlap between electron and hole wavefunctions decreases with increasing shell thickness, thus the lifetime increases. As for the NCs with extremely thin shell (∼1 ML; 1 ML = 0.35 nm), the PL lifetime seems much longer than expected. This suggests that the thin shells seem imperfect and work rather a kind of trap sites than layers

    Synthesis, characterization, and its PL dynamics of colloidal type II CdTe/CdSe nanocrystals

    Get PDF
    We describe our improved synthesis and optical properties of high quality type II CdTe/CdSe nanocrystals (NCs). Specifically, clear shell-thickness dependences have been observed in the absorption and photoluminescence (PL) spectra and PL decay profiles as well. The magnitude of the lowest absorption band decreases drastically with large redshift as the shell thickness increases. The origin will be discussed on the bases of the model where the spatial configuration of the lowest electron-hole pair in the NCs changes from that of type I to type II as the shell thickness increases. As for the PL lifetime of the lowest electron-hole excitations, substantial increase is observed with increasing shell thickness. This can also be understood by considering the spatial configuration; spatial overlap between electron and hole wavefunctions decreases with increasing shell thickness, thus the lifetime increases. As for the NCs with extremely thin shell (∼1 ML; 1 ML = 0.35 nm), the PL lifetime seems much longer than expected. This suggests that the thin shells seem imperfect and work rather a kind of trap sites than layers

    Novel functional anti-HER3 monoclonal antibodies with potent anti-cancer effects on various human epithelial cancers

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    Resistance of progressive cancers against chemotherapy is a serious clinical problem. In this context, human epidermal growth factor receptor 3 (HER3) can play important roles in drug resistance to HER1- and HER2- targeted therapies. Since clinical testing of anti-HER3 monoclonal antibodies (mAbs) such as patritumab could not show remarkable effect compared with existing drugs, we generated novel mAbs against anti-HER3. Novel rat mAbs reacted with HEK293 cells expressing HER3, but not with cells expressing HER1, HER2 or HER4. Specificity of mAbs was substantiated by the loss of mAb binding with knockdown by siRNA and knockout of CRISPR/Cas9-based genome-editing. Analyses of CDR sequence and germline segment have revealed that seven mAbs are classified to four groups, and the binding of patritumab was inhibited by one of seven mAbs. Seven mAbs have shown reactivity with various human epithelial cancer cells, strong internalization activity of cell-surface HER3, and inhibition of NRG1 binding, NRG1-dependent HER3 phosphorylation and cell growth. Anti-HER3 mAbs were also reactive with in vivo tumor tissues and cancer tissue-originated spheroid. Ab4 inhibited in vivo tumor growth of human colon cancer cells in nude mice. Present mAbs may be superior to existing anti-HER3 mAbs and support existing anti-cancer therapeutic mAbs

    New Chemical Family of [ n

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    Ripe Tomato Saponin Esculeoside A and Sapogenol Esculeogenin A Suppress CD4+ T Lymphocyte Activation by Modulation of Th2/Th1/Treg Differentiation

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    We report that esculeoside A (EsA), a glycoside and a major component in ripe tomato fruit, ameliorated experimental dermatitis in mice. However, the underlying immunologic molecular mechanisms are unknown. The present study examined its underlying immune nutrition mechanism using concanavalin A (ConA)-blast mouse splenocyte primary culture. We found that EsA and its sapogenol esculeogenin A (Esg-A) concentration-dependently suppressed T-lymphoproliferation using CFSE-labeled flow-cytometry and water-soluble tetrazolium (WST) assay. Using ELISA and q-PCR methods, EsA/Esg-A showed profound decreases in T helper 2 (Th2)-relevant interleukin-4 (IL-4) secretion and mRNA expression, and GATA3 expression. Moreover, EsA/Esg-A suppressed CD4+ T-lymphocyte activation by decreasing IL-2 secretion and mRNA expression and CD25+ cell proportion. Further, EsA/Esg-A alleviated Treg suppressive activity by reducing IL-10 secretion, Foxp3 mRNA expression, and cell numbers. We suggest the immune nutrition function by tomato component, and highlight that EsA/Esg-A are capable of reducing CD4+ T-lymphocyte activation via a reduction in Th2-lymphocyte activity by modulation of Th2/Th1/Treg subunit differentiation

    Depression and anxiety symptoms among Vietnamese migrants in Japan during the COVID-19 pandemic

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    Abstract This study aimed to examine the mental health status and related factors among Vietnamese migrants in Japan during the COVID-19 pandemic. We conducted an online cross-sectional survey between September 21 and October 21, 2021. Along with Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder 7-item (GAD-7) scores, we collected data on demographics, changes in socioeconomic status due to the pandemic, language proficiency, social support, and health conditions. Multivariate logistic regression was performed to identify factors related to symptoms of depression and anxiety. Among 621 participants who completed the questionnaire, moderate-to-severe symptoms of depression (PHQ-9 score ≥ 10 points) and mild-to-severe symptoms of anxiety (GAD-7 score ≥ 5 points) were observed in 203 (32.7%) and 285 (45.9%) individuals, respectively. Factors related to depressive symptoms were age (95% confidence interval [CI]=0.89-0.99), pre-existing health conditions (95% [CI]=1.61–3.76), and a low subjective socioeconomic status (95% [CI]=1.64–3.71). Factors related to anxiety symptoms were being single (95% [CI]=1.01–2.93), having pre-existing health conditions (95% [CI]=1.63–3.88), subjective socioeconomic status (95% [CI]=1.87–3.97), and absence of a partner to discuss one’s health with (95% [CI]=1.11–2.47). Vietnamese migrants in Japan experienced a decrease in income, worsening working conditions, and poor mental health status during the COVID-19 pandemic. Further investigations are necessary to find an effective way to increase their social support and mitigate socioeconomic adversities
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