Publications by authors named "Emiko Koyama"

26 Publications

  • Page 1 of 1

Cephalopods-Inspired Rapid Self-Healing Nanoclay Composite Coatings with Oxygen Barrier and Super-Bubble-Phobic Properties.

ACS Appl Mater Interfaces 2021 Jul 20. Epub 2021 Jul 20.

Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), Higashi 1-1-1, Tsukuba, Ibaraki 305-8565, Japan.

Polymeric coatings with oxygen barrier properties are an important technology in food packaging that can extend the shelf life of food products and reduce waste. Although a typical technology in practical use is the deposition of metal or inorganic materials between multilayer films to reduce the oxygen transmission rate, once the film is damaged, oxygen permeates through the damaged area, damaging the packaged food. In addition, nanobrick wall structures consisting of nanoplatelet bricks have the potential to replace barrier films made of inorganic materials; however, they similarly lack repair performance or have slow repair speed despite having repair performance. Inspired by the rapid self-repair mechanism of cephalopods, the study develops a nanoclay-containing coating that can rapidly repair surface damage via water within 10 s. By introducing CaCl-derived counterions and montmorillonite for nanobrick wall structures into polyelectrolyte multilayers stacked by layer-by-layer self-assembly, the noncovalent polymer network is increased, resulting in mimicking a strong cephalopod-derived β-sheet structure and noncovalent intermolecular interactions derived from cephalopods. The high water retention at the surface showed super-bubble-phobicity in water and inhibited gas permeation. The oxygen permeability of the coatings with more than a certain amount of montmorillonite was less than 1/100 of that of bare polyethylene. The ultrafast self-healing gas barrier coating has the potential to be used not only for food products but also for electronics and pharmaceutical packaging and gas separation applications. The key technology developed in this study provides novel insights into the construction of self-healing membranes made of composite materials and will contribute to the formation of a sustainable society.
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http://dx.doi.org/10.1021/acsami.1c09588DOI Listing
July 2021

Evidence for association of vasopressin receptor 1A promoter region repeat with childhood onset aggression.

J Psychiatr Res 2021 Aug 27;140:522-528. Epub 2021 May 27.

Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science & Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.

Objective: Childhood onset aggression can cause major suffering to affected families and is associated with many negative outcomes in the child's later life, including poor academic performance, adolescent delinquency, drug abuse, depression and antisocial personality disorder. Currently available prevention and intervention strategies have limited efficacy, but a better understanding of underlying genetic and neurobiological factors can lead to more effective prevention and treatment strategies, through genetic screening programs and novel therapies.

Method: This study examined the RS1 (n = 299 aggression, n = 192 controls) and RS3 (n = 291 aggression, n = 189 controls) microsatellite repeats within the promoter region of the vasopressin receptor 1A gene (AVPR1A) and their association with extreme childhood aggression, as assessed by the Child Behavior Checklist (CBCL), as well as the Teacher Report Form (TRF) and Youth Self Report (YSR). Binary logistic regression was used to model the relationship between microsatellite length and childhood aggression. Age and sex were used as covariates.

Results: Logistic regression revealed a nominally significant association between one specific RS3 repeat and non-aggressive status. No association was found for any of the RS1 repeats. In a separate model, grouping repeats into short and long, carriers of long RS3 repeats were nominally significantly associated with non-aggressive status.

Conclusions: These findings suggest a role for AVPR1A and its RS3 microsatellite in extreme childhood aggression and could lead to a better understanding of the biological pathways of aggressive behavior. However, independent replication and further research into the functionality of studied genetic variants is required.
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http://dx.doi.org/10.1016/j.jpsychires.2021.05.062DOI Listing
August 2021

Increased levels of circulating cell-free mtDNA in plasma of late life depression subjects.

J Psychiatr Res 2021 07 8;139:25-29. Epub 2021 May 8.

Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Adult Neurodevelopment and Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.

Background: Oxidative stress (OS) has been implicated in the pathophysiology of late-life depression (LLD). Mitochondria are the primary source of oxidative stress and can be significantly damaged with increased OS. Circulating cell-free mtDNA (ccf-mtDNA) is a marker of cellular stress and mitochondria damage triggered by oxidative stress.

Methods: We evaluated the plasma levels of ccf-mtDNA in between 32 LLD and 21 never-depressed participants. We also investigated the association between ccf-mtDNA and the severity of depressive episodes and cognition performance.

Results: We found a higher ccf-mtDNA level in LLD cases compared with controls (t = -2.91, p = 0.005). Also, ccf-mtDNA was significantly correlated with the severity of depression (r = 0.42, p = 0.001). There was no significant correlation between ccf-mtDNA and measures of cognitive decline.

Limitations: The small sample size and cross-sectional design were the main limitations of this study.

Conclusion: Our results suggest that LLD is associated with elevated mitochondrial damage and cellular stress. If validated, the measurement of ccf-mtDNA in LLD can guide the development of novel treatments focused on cytoprotection and reduction of mitochondrial dysfunction for this condition.
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http://dx.doi.org/10.1016/j.jpsychires.2021.05.015DOI Listing
July 2021

Increased levels of circulating cell-free mtDNA in plasma of late life depression subjects.

J Psychiatr Res 2021 07 8;139:25-29. Epub 2021 May 8.

Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada; Adult Neurodevelopment and Geriatric Psychiatry Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.

Background: Oxidative stress (OS) has been implicated in the pathophysiology of late-life depression (LLD). Mitochondria are the primary source of oxidative stress and can be significantly damaged with increased OS. Circulating cell-free mtDNA (ccf-mtDNA) is a marker of cellular stress and mitochondria damage triggered by oxidative stress.

Methods: We evaluated the plasma levels of ccf-mtDNA in between 32 LLD and 21 never-depressed participants. We also investigated the association between ccf-mtDNA and the severity of depressive episodes and cognition performance.

Results: We found a higher ccf-mtDNA level in LLD cases compared with controls (t = -2.91, p = 0.005). Also, ccf-mtDNA was significantly correlated with the severity of depression (r = 0.42, p = 0.001). There was no significant correlation between ccf-mtDNA and measures of cognitive decline.

Limitations: The small sample size and cross-sectional design were the main limitations of this study.

Conclusion: Our results suggest that LLD is associated with elevated mitochondrial damage and cellular stress. If validated, the measurement of ccf-mtDNA in LLD can guide the development of novel treatments focused on cytoprotection and reduction of mitochondrial dysfunction for this condition.
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http://dx.doi.org/10.1016/j.jpsychires.2021.05.015DOI Listing
July 2021

Pharmacogenomic Studies in Intellectual Disabilities and Autism Spectrum Disorder: A Systematic Review: Études Pharmacogénomiques en Déficiences Intellectuelles et Trouble du Spectre de L'autisme: Une Revue Systématique.

Can J Psychiatry 2020 Nov 23:706743720971950. Epub 2020 Nov 23.

Tanenbaum Centre for Pharmacogenetics, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.

Background: Individuals with intellectual disability (ID) and autism spectrum disorder (ASD) often receive psychotropic medications such as antipsychotics and antidepressants to treat aberrant behaviors and mood symptoms, frequently resulting in polypharmacy and drug-related adverse effects. Pharmacogenomic (PGx) studies with ASD and/or ID (ASD/ID) have been scarce despite the promise of optimizing treatment outcomes. We reviewed the literature on PGx studies with antipsychotics and antidepressants (e.g., treatment response and adverse effects) in ASD/ID.

Methods: We performed a systematic review using MEDLINE, Embase, and PsycINFO, including peer-reviewed original articles in English referring to PGx in the treatment of ASD/ID in any age groups (e.g., treatment response and adverse effects).

Results: A total of 28 PGx studies using mostly candidate gene approaches were identified across age groups. Notably, only 3 studies included adults with ASD/ID while the other 25 studies focused specifically on children/adolescents with ASD/ID. Twelve studies primarily investigated treatment response, of which 5 and 6 studies included patients treated with antipsychotics and antidepressants, respectively. Most interesting results for response were reported for 2 sets of candidate gene studies, namely: (1) The (rs6280) polymorphism was examined in patients treated with risperidone in 3 studies, 2 of which reported an association with risperidone treatment response and (2) the 5-HTTLPR polymorphism and treatment response to antidepressants which was investigated in 4 studies, 3 of which reported significant associations. In regard to side effects, 9 of 15 studies focused on hyperprolactinemia in patients treated with risperidone. Among them, 7 and 5 studies examined the impact of and polymorphisms, respectively, yielding mostly negative study findings.

Conclusions: There is limited data available on PGx in individuals with ASD/ID and in particular in adults. Given the potential for PGx testing in improving treatment outcomes, additional PGx studies for psychotropic treatment in ASD/ID across age groups are warranted.
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http://dx.doi.org/10.1177/0706743720971950DOI Listing
November 2020

Pharmacogenomic Studies in Intellectual Disabilities and Autism Spectrum Disorder: A Systematic Review: Études Pharmacogénomiques en Déficiences Intellectuelles et Trouble du Spectre de L'autisme: Une Revue Systématique.

Can J Psychiatry 2020 Nov 23:706743720971950. Epub 2020 Nov 23.

Tanenbaum Centre for Pharmacogenetics, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.

Background: Individuals with intellectual disability (ID) and autism spectrum disorder (ASD) often receive psychotropic medications such as antipsychotics and antidepressants to treat aberrant behaviors and mood symptoms, frequently resulting in polypharmacy and drug-related adverse effects. Pharmacogenomic (PGx) studies with ASD and/or ID (ASD/ID) have been scarce despite the promise of optimizing treatment outcomes. We reviewed the literature on PGx studies with antipsychotics and antidepressants (e.g., treatment response and adverse effects) in ASD/ID.

Methods: We performed a systematic review using MEDLINE, Embase, and PsycINFO, including peer-reviewed original articles in English referring to PGx in the treatment of ASD/ID in any age groups (e.g., treatment response and adverse effects).

Results: A total of 28 PGx studies using mostly candidate gene approaches were identified across age groups. Notably, only 3 studies included adults with ASD/ID while the other 25 studies focused specifically on children/adolescents with ASD/ID. Twelve studies primarily investigated treatment response, of which 5 and 6 studies included patients treated with antipsychotics and antidepressants, respectively. Most interesting results for response were reported for 2 sets of candidate gene studies, namely: (1) The (rs6280) polymorphism was examined in patients treated with risperidone in 3 studies, 2 of which reported an association with risperidone treatment response and (2) the 5-HTTLPR polymorphism and treatment response to antidepressants which was investigated in 4 studies, 3 of which reported significant associations. In regard to side effects, 9 of 15 studies focused on hyperprolactinemia in patients treated with risperidone. Among them, 7 and 5 studies examined the impact of and polymorphisms, respectively, yielding mostly negative study findings.

Conclusions: There is limited data available on PGx in individuals with ASD/ID and in particular in adults. Given the potential for PGx testing in improving treatment outcomes, additional PGx studies for psychotropic treatment in ASD/ID across age groups are warranted.
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http://dx.doi.org/10.1177/0706743720971950DOI Listing
November 2020

Hexagonal array formation by intermolecular halogen bonding using a binary blend of linear building blocks: STM study.

Chem Commun (Camb) 2019 Apr 15;55(27):3955-3958. Epub 2019 Mar 15.

National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.

Hexagonal arrays were fabricated via intermolecular halogen bonding between two linear molecular building blocks in a bicomponent blend. The substitution position of the pyridine N atom involved in the halogen bond plays an important role in the formation of the hexagonal structures.
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http://dx.doi.org/10.1039/c9cc00532cDOI Listing
April 2019

Microwave Flow: A Perspective on Reactor and Microwave Configurations and the Emergence of Tunable Single-Mode Heating Toward Large-Scale Applications.

Chem Rec 2019 Jan 20;19(1):188-203. Epub 2018 Nov 20.

SAIDA FDS, INC., 143-10 Isshiki, Yaizu, Shizuoka, 425-0054, Japan.

Microwave heating in chemical reactions was first reported in 1986. There have since been many reports employing microwave heating in organic chemistry, where microwave heating has afforded higher yields of products in shorter time periods. However, such reactions are challenging to scale in batch due to the limited penetration depth of microwaves as well as the wave propagation dependence on cavity size. Continuous flow has addressed both these issues, enabling scalability of microwave processes. As such, a host of reports employing microwave flow chemistry have emerged, employing various microwave heating and reactor configurations in the context of either custom-built or commercial apparatus. The focus of this review is to present the benefits of microwave heating in the context of continuous flow and to characterize the different types of microwave flow apparatus by their design (oscillator, cavity type and reactor vessel). We advocate the adoption of tunable, solid-state oscillator single-mode microwave flow reactors which are more versatile heaters, impart better process control and energy efficiency toward laboratory and larger-scale synthetic chemistry applications.
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http://dx.doi.org/10.1002/tcr.201800104DOI Listing
January 2019

Light-induced mechanical response in crosslinked liquid-crystalline polymers with photoswitchable glass transition temperatures.

Nat Commun 2018 08 13;9(1):3234. Epub 2018 Aug 13.

Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Higashi 1-1-1, Tsukuba, Ibaraki, 305-8565, Japan.

Energy conversion of light into mechanical work is of fundamental interest in applications. In particular, diligent molecular design on nanoscale, in order to achieve efficient photomechanical effects on macroscopic scale, has become one of the most interesting study topics. Here, by incorporating a "photomelting" azobenzene monomer crosslinked into liquid crystalline (LC) networks, we generate photoresponsive polymer films that exhibit reversible photoswitchable glass transition temperatures (T) at room temperature (~20 °C) and photomechanical actuations under the stimulus of UV/visible light. The trans-to-cis isomerization of azo chromophores results in a change in T of the crosslinked LC polymers. The T of the polymer network is higher than room temperature in the trans-form and lower than room temperature in the cis-form. We demonstrate the photoswitchable T contribute to the photomechanical bending and a new mechanism for photomechanical bending that attributes the process to an inhomogeneous change in T of the film is proposed.
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http://dx.doi.org/10.1038/s41467-018-05744-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6089925PMC
August 2018

Cannabis use, other substance use, and co-occurring mental health concerns among youth presenting for substance use treatment services: Sex and age differences.

J Subst Abuse Treat 2018 08 9;91:12-19. Epub 2018 May 9.

Centre for Addiction and Mental Health, 80 Workman Way, Toronto, ON, Canada; Department of Psychiatry, University of Toronto, Toronto, ON, Canada. Electronic address:

Cannabis use among youth is of significant concern given the potential negative health impacts on young people. This study describes the mental health characteristics, cannabis use, and substance use profiles of youth aged 14 to 24 years seen at the Youth Addiction and Concurrent Disorders Service at the Centre for Addiction and Mental Health, through an age and gender lens. Almost all participating youth indicated lifetime cannabis use. Substance use and mental health profiles among those indicating a history of cannabis use differed along sex and age. Male youth were more likely to use cannabis more frequently, while female youth were more likely to use greater variety of substances and display more co-occurring mental health problems. Adolescent problematic substance use tended to co-occur with externalizing problems whereas problematic young adult substance use tended to co-occur with internalizing problems. Implications for the integrated, coordinated care of substance use and mental health concerns, with attention to the unique needs of subgroups of youth, are discussed.
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http://dx.doi.org/10.1016/j.jsat.2018.05.001DOI Listing
August 2018

Selective, Scalable Synthesis of C-Fullerene/Indene Monoadducts Using a Microwave Flow Applicator.

J Org Chem 2018 04 11;83(8):4348-4354. Epub 2018 Apr 11.

National Institute of Advanced Industrial Science and Technology , Tsukuba Central 5, 1-1-1 Higashi , Tsukuba , Ibaraki 305-8568 , Japan.

The synergy of continuous processing and microwave heating technologies has unlocked scalable (g/h), safe and efficient reaction conditions for synthesis of fullerene/indene-based organic photovoltaic acceptor materials in a nonchlorinated solvent with levels of productivity unparalleled by previous syntheses. The microwave flow reactor sustains high temperature while employing short residence times, reaction conditions which uniquely allow the selective synthesis of fullerene/indene monoadducts. Design of experiments analysis revealed residence time as the most crucial factor for conversion and selectivity control.
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http://dx.doi.org/10.1021/acs.joc.7b03209DOI Listing
April 2018

The Versican G1 Fragment and Serum-Derived Hyaluronan-Associated Proteins Interact and Form a Complex in Granulation Tissue of Pressure Ulcers.

Am J Pathol 2018 02 21;188(2):432-449. Epub 2017 Nov 21.

Department of Advanced Medicine, National Center for Geriatrics and Gerontology, Obu, Japan; School of Nursing and Health, Aichi Prefectural University, Nagoya, Japan. Electronic address:

The hyaluronan (HA)-rich extracellular matrix plays dynamic roles during tissue remodeling. Versican and serum-derived HA-associated protein (SHAP), corresponding to the heavy chains of inter-α-trypsin inhibitor, are major HA-binding molecules in remodeling processes, such as wound healing. Versican G1-domain fragment (VG1F) is generated by proteolysis and is present in either remodeling tissues or the mature dermis. However, the macrocomplex formation of VG1F has not been clarified. Therefore, we examined the VG1F-containing macrocomplex in pressure ulcers characterized by chronic refractory wounds. VG1F colocalized with SHAP-HA in specific regions of the granulation tissue but not with fibrillin-1. A unique VG1F-SHAP-HA complex was isolated from granulation tissues using gel filtration chromatography and subsequent cesium chloride-gradient ultracentrifugation under dissociating conditions. Consistent with this molecular composition, recombinant versican G1, but not versican G3, interacted with the two heavy chains of inter-α-trypsin inhibitor. The addition of recombinant VG1 in fibroblast cultures enhanced VG1F-SHAP-HA complex deposition in the pericellular extracellular matrix. Comparison with other VG1F-containing macrocomplexes, including dermal VG1F aggregates, versican-bound microfibrils, and intact versican, highlighted the tissue-specific organization of HA-rich extracellular matrix formation containing versican and SHAP. The VG1F-SHAP-HA complex was specifically detected in the edematous granulation tissues of human pressure ulcers and in inflamed stages in a mouse model of moist would healing, suggesting that the complex provides an HA-rich matrix suitable for inflammatory reactions.
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http://dx.doi.org/10.1016/j.ajpath.2017.10.015DOI Listing
February 2018

Language disorder and retrospectively reported sexual abuse of girls: severity and disclosure.

J Child Psychol Psychiatry 2017 Oct 13;58(10):1114-1121. Epub 2017 Apr 13.

Child, Youth and Emerging Adult Service, Centre for Addiction and Mental Health, Toronto, ON, Canada.

Background: Despite emerging evidence for an association between communication disorders and maltreatment, little research has examined sexual abuse characteristics or disclosure experiences among individuals with language disorder (LD). Given that communication difficulties may constitute a barrier to disclosure, the disclosure experiences among individuals with and without communication difficulties may also differ.

Methods: Five-year-old children identified with a language and/or speech disorder from a nonclinical community sample and a control group were followed to adulthood in a prospective longitudinal study. At age 31, participants completed a behaviorally specific questionnaire on experiences of sexual abuse and questionnaires on disclosure experiences and social reactions to disclosure. Due to low endorsement of sexual victimization among male participants and low sample size, results are reported for women only and exclude nine participants with speech disorder without LD. Participation rates were 28 of 40 in the LD cohort and 45 of 51 controls. Sexual victimization severity was defined using an index combining five indicators (duration, invasiveness, relationship to perpetrator, coercive tactics used, and number of perpetrators). Subthreshold sexual victimization was defined as a single, noncontact incident with a perpetrator unknown to the child; experiences with greater severity were classified as child sexual abuse.

Results: Among women who reported sexual victimization by age 18, invasiveness and overall severity were greater in the LD cohort than in the control cohort. Women in the LD cohort (43%) were more likely than controls (16%) to report child sexual abuse, excluding subthreshold experiences. There were no differences between cohorts in probability of disclosure, latency to disclosure, or social reactions.

Conclusions: Women with a history of child LD in a nonclinical sample reported substantial child sexual abuse experiences. Implications for understanding associations between LD and mental health and for prevention and early intervention are discussed.
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http://dx.doi.org/10.1111/jcpp.12723DOI Listing
October 2017

Photoinduced crystal-to-liquid phase transitions of azobenzene derivatives and their application in photolithography processes through a solid-liquid patterning.

Org Lett 2014 Oct 12;16(19):5012-5. Epub 2014 Sep 12.

Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST) , Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.

The direct and reversible transformation of matter between the solid and liquid phases by light at constant temperature is of great interest because of its potential applications in various manufacturing settings. We report a simple molecular design strategy for the phase transitions: azobenzenes having para-dialkoxy groups with a methyl group at the meta-position. The photolithography processes were demonstrated using the azobenzene as a photoresist in a single process combining development and etching of a copper substrate.
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http://dx.doi.org/10.1021/ol502223uDOI Listing
October 2014

Bipyridine derivatives at a solid/liquid interface: effects of the number and length of peripheral alkyl chains.

Langmuir 2010 Mar;26(5):3376-81

National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan.

Bipyridine derivatives (bpys) with various number and length of peripheral alkyl chains (with carbon numbers of n = 11-17) were synthesized, and their self-assembled monolayers were observed by scanning tunneling microscopy (STM) at a 1-phenyloctane/highly oriented pyrolytic graphite (HOPG) interface. The effects of the number, the substitution position, and the length of alkyl chains on the two-dimensional structures were systematically studied. Bpys substituted by a single alkyl chain in the p-position on each side adopted an almost linear form with zigzag-type alignment of the pi-conjugated unit, whereas, in the case of m-substitution, the bpys showed Z-shaped morphology with interdigitated alkyl chains. In both cases, no odd-even alkyl chain length effects were observed. The bpys with double alkyl chains at m- and p-positions displayed odd-even alkyl chain effects, suggesting that the formation of two-dimensional structure is dominated by the interactions between alkyl chains. Bpys with triple alkyl chains at o-, m-, and p-positions also showed odd-even alkyl chain effects, but only for the higher number of carbon atoms in the alkyl chain unit (n = 14-17). These results indicate that concerted intermolecular interactions of the alkyl chain unit introduce the odd-even chain length effect on the self-assembled two-dimensional structure. After coordination of PdCl(2), odd-even effects were quenched, and bpys were converged into the same lamellar structure, in which the molecules are almost linear. All the structural differences due to the odd-even alkyl chain length effect were explained in terms of intermolecular and molecule-substrate interactions.
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http://dx.doi.org/10.1021/la903156mDOI Listing
March 2010

Innovative platform for transmission localized surface plasmon transducers and its application in detecting heavy metal Pd(II).

Anal Chem 2009 Sep;81(18):7703-12

National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.

Transmission localized surface plasmon resonance (T-LSPR) transducers based on the characteristic surface plasmon absorption band of Au island films have become increasingly attractive. The first and main bottleneck hampering the development of T-LSPR sensors is instability, manifested as change in the surface plasmon absorbance band following immersion in organic solvents and aqueous solutions. In this paper, we innovate the platform for T-LSPR transducer by using remarkably stable and highly adhesive Au/Al(2)O(3) nanocomposite film. Isolated Au nanoparticles embedded in dielectric matrix Al(2)O(3) were prepared by a simple one-step radio frequency magnetron cosputtering technique. The obtained nanocomposite film is exceedingly stable during immersion in solvents, drying, and binding of different molecules; it successfully passes the adhesive tape test and sonication treatment. The superior stability and adhesion, obtained without the use of any intermediate adhesion layer or protective overlayer, is attributed to (1) the Au nanoparticles embedment and Al(2)O(3) rim formation during the sputtering process and (2) the resistance of element Al in matrix to the nucleophilic attack by the solvent molecules. Given this success, we believe that the Au/Al(2)O(3) nanocomposite film holds promise as an innovative sensing platform in T-LSPR detection technology, as demonstrated here for the Pd(II) sensing process with excellent sensitivity and low detection limit.
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http://dx.doi.org/10.1021/ac901137zDOI Listing
September 2009

Emerging adult outcomes of adolescent psychiatric and substance use disorders.

Addict Behav 2009 Oct 2;34(10):800-5. Epub 2009 Apr 2.

Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, Canada.

This study investigates the age 25 outcomes of late adolescent mental health and substance use disorders. A hierarchical cluster analysis of age 19 DSM-III-R mental health and substance diagnoses placed participants into one of 9 clusters: Anxious, Depressed, Antisocial, Drug Abuser, Problem Drinker, Anxious Drinker, Depressed Drug Abuser and Antisocial Drinker, and No Diagnosis. Diagnoses were generated from the University of Michigan Composite International Diagnostic Interview. Repeated measures multivariate analyses of variance revealed distinct trajectories of improvement and decline among the 9 clusters. Clusters with co-occurring substance and mental health disorders improved over adolescent levels, but continued to have higher levels of depression symptoms, poorer global functioning, and higher levels of substance use than the No Diagnosis cluster. Members of the The Problem Drinkers cluster, who tended to have alcohol use disorders only at age 19, did not differ from their peers with no diagnoses. Drug use disorders in adolescence, with or without a co-occurring mental health disorders, were associated with a poor prognosis in emerging adulthood. Clinical interventions should distinguish among these diverse clinical presentations.
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http://dx.doi.org/10.1016/j.addbeh.2009.03.035DOI Listing
October 2009

Development of phonological awareness in bilingual chinese children.

J Psycholinguist Res 2008 Nov;37(6):405-18

Department of Human Development and Applied Psychology, Ontario Institute for Studies in Education of the University of Toronto, 252 Bloor Street West 9th Floor, Toronto, ON, Canada, M5S1V6.

This study investigated the phonological awareness of 219 first, second, and fourth grade Cantonese-speaking children from the south of China, who received immersion Mandarin instruction beginning in the first grade. Children received onset, rime and tone awareness tasks in Cantonese and Mandarin. Children performed better on the Cantonese onset awareness task in grade one, but the difference disappeared in higher grades. However, their performance on the rime and tone awareness tasks was better in Mandarin. These results reflect the phonological structure of the two languages: Mandarin has a more complex onset system, whereas Cantonese has more complex tone and rime systems. Moreover, children's phonological awareness increased faster in Mandarin, which likely resulted from Mandarin instruction. Confirmatory factor analysis suggested that onset-rime awareness is a universal construct, whereas tone awareness is a language-specific construct.
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http://dx.doi.org/10.1007/s10936-008-9085-zDOI Listing
November 2008

Models and determinants of vocabulary growth from kindergarten to adulthood.

J Child Psychol Psychiatry 2008 Jun 10;49(6):626-34. Epub 2008 Mar 10.

Centre for Addiction and Mental Health, Toronto, Canada.

Background: Increasing evidence suggests that childhood language problems persist into early adulthood. Nevertheless, little is known about how individual and environmental characteristics influence the language growth of individuals identified with speech/language problems.

Method: Individual growth curve models were utilised to examine how speech/language impairment and environmental variables (socioeconomic status, family separation, and maternal factors) influence vocabulary development from age 5 to 25. Participants were taken from a community sample of children initially diagnosed with speech/language problems at age 5 and their sex- and age-matched controls.

Results: The language impaired group had significantly poorer receptive vocabulary than the speech impaired and control groups throughout the 20-year period. Family income was a significant predictor of vocabulary growth when considered separately, but ceased to be a predictor when language impairment status was taken into account. Maternal education and family separation were determinants of vocabulary at age 5, over and above language impairment status.

Conclusion: Language impairment is a significant risk factor for vocabulary development from childhood to adulthood. Individuals with speech impairment were less impaired on receptive vocabulary than individuals with language impairment. Further investigation into maternal and familial risk factors may provide targets for early intervention with children at risk for language impairment.
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http://dx.doi.org/10.1111/j.1469-7610.2008.01878.xDOI Listing
June 2008

Odd-even effect and metal induced structural convergence in self-assembled monolayers of bipyridine derivatives.

Chem Commun (Camb) 2007 Apr 19(13):1343-5. Epub 2007 Jan 19.

Nanoarchitectonics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8562, Japan.

Scanning tunneling microscopy (STM) observations reveal that bipyridine derivatives which exhibit various two-dimensional structures due to the odd-even chain length effect are converged into a lamellar structure upon metal coordination.
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http://dx.doi.org/10.1039/b616601fDOI Listing
April 2007

Two-dimensional structure control by molecular width variation with metal coordination.

Langmuir 2006 Aug;22(16):6910-4

Nanoarchitectonics Research Center, SYNAF, Research Institute for Computational Sciences, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan.

The self-assembled monolayer of bipyridine derivative 1, which has two alkyl chains on each end, at the HOPG/1-phenyloctane interface was studied by in situ scanning tunneling microscopy (STM). The detailed mechanism of a spontaneous change in the monolayer packing pattern by Pd coordination was studied. Uncomplexed 1 existed in a bent form in the monolayer, and the alkyl chains were interdigitated, whereas Pd-complexed 1 was in a straight form and the alkyl chains were not interdigitated. An intermediate state of 1 was successfully observed during metal coordination. The structure was the bent form with noninterdigitated alkyl chains. Equilibrium intermolecular distances reported from ab initio calculations indicate that the molecular width of the central aromatic part of uncomplexed 1 (7.5 A) is substantially smaller than that of the peripheral alkyl chain part (9.2 A). The bent form was suitable for covering up the surface to maximize the packing density. However, the molecular width of the aromatic unit of Pd-complexed 1 (9.1 A) was almost identical to that of the alkyl chain unit (9.2 A). Therefore, Pd-complexed 1 took the straight form in the monolayer. The observation of surface coverage by STM suggests that the bent form increases the packing density by as much as 16% compared with that of the straight form. These results indicate that the control of molecular width can be used to design molecular templates for nanostructure formation.
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http://dx.doi.org/10.1021/la0606244DOI Listing
August 2006

Surface potential switching by metal ion complexation/decomplexation using bipyridinethiolate monolayers on gold.

J Phys Chem B 2006 May;110(18):9195-203

Nanotechnology Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.

Surface potential switching on gold(111) surfaces is induced by complexation/decomplexation reactions of a bipyridine (BP) derivative and palladium(II) chloride, as observed by Kelvin probe force microscopy (KFM). On the basis of the theoretical predictions, a 4-(5-phenylethynyl-2,2'-bipyridine-5'-yl-ethynyl)benzenethiol (PhBP) derivative was synthesized and used as an active monolayer to catch transition metal ions. By using the microcontact printing (CP) technique, micron-size patterned PhBP monolayers, which act as effective hosts to coordinate palladium(II) chloride, were prepared on gold(111) surfaces. The KFM signal decreases by complexation of the Pd(II) chloride in PhBP monolayers and is recovered by removal of Pd ions using an ethylenediamine solution, as confirmed by X-ray photoelectron spectroscopy. This process is reversible, indicating that the surface potential switching is realized by complexation/decomplexation of Pd(II). A CP PhBP monolayer, when it detects the target palladium ion, shows sensitivity for the picomolar level detection judged from surface potential changes in KFM measurements. The dipole moment estimated by the surface potentials is much smaller than the calculated value, indicating that mechanisms for the reduction of the surface dipole moment exist in real monolayers prepared by the CP method.
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http://dx.doi.org/10.1021/jp056821dDOI Listing
May 2006

[3]rotaxane synthesized via covalent bond formation can recognize cations forming a sandwich structure.

Chem Commun (Camb) 2005 Feb 15(6):749-51. Epub 2004 Dec 15.

Nanoarchitectonics Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, 305-8562, Japan.

A novel [3]rotaxane composed of two 25-membered crownophanes and one axle molecule having two anthryl end groups was successfully synthesized via covalent bond formation followed by aminolysis, and can incorporate caesium ion into the space between the two macrocycles as a 1 : 1 sandwich-type complex, whereas it makes a 1 : 2 complex with lithium ion.
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http://dx.doi.org/10.1039/b413715aDOI Listing
February 2005

Synthesis of [1]rotaxane via covalent bond formation and its unique fluorescent response by energy transfer in the presence of lithium ion.

J Am Chem Soc 2004 Oct;126(42):13568-9

Department of Applied Chemistry, Utsunomiya University, 7-1-2 Youtou, Utsunomiya 321-8585, Japan.

Although there have been a lot of reports on the synthesis and properties of [n]rotaxanes (mainly n = 2), only a few reports on the synthesis of [1]rotaxane has been published by Vögtle's group and others (see ref 5). Generally speaking, [1]rotaxane might be expected to exhibit properties different from other rotaxanes, because the rotor and the axle in the [1]rotaxane is bound covalently and closely. We report on a novel method to make [1]rotaxanes via covalent bond formation from a macrocyclic compound. That is, we first prepared a bicyclic compound from macrocycle and then proceeded to [1]rotaxane by aminolysis. This is the first synthetic example of preparation of [1]rotaxane via covalent bond formation, not utilizing weak interactions such as hydrogen bonding, charge transfer, via metal complexation, etc. This method might provide a powerful and new tool for construction of [1]rotaxane as a new supramolecular system. In addition, we investigated energy transfer from rotor to axle using [1]rotaxane that we prepared. Energy transfer occurred perfectly from the naphthalene ring of the rotor to the anthracene ring of the axle. We found also that only lithium ion among alkali ions can drastically enhance the fluorescence intensity. This finding could be applicable to ion-sensing systems, switching devices, and so on.
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http://dx.doi.org/10.1021/ja046929rDOI Listing
October 2004

STM-based molecular detection of "catch-and-release" of protons for bipyridine bound to phenylene-ethynylene thiol.

Chem Commun (Camb) 2004 Jul 14(14):1626-7. Epub 2004 Jun 14.

Nanoarchitectonics Research Center (NARC), National Institute of Advanced Industrial Science and Technology, Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan.

The protonation/deprotonation response of a novel bipyridine containing (phenylene-ethynylene) thiol adsorbed to a Au surface was investigated with scanning tunneling microscopy (STM), showing reversible changes in the average heights (approximately 50 spots) and the height distribution arising from protonation/deprotonation.
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http://dx.doi.org/10.1039/b402251cDOI Listing
July 2004

Remote Pummerer Reaction via Intermolecular Through-Space Interaction between Sulfonium and Sulfenyl Sulfur Atoms.

J Org Chem 1999 Apr;64(9):3190-3195

Department of Chemistry and Tsukuba Advanced Research Alliance Center, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.

The remote Pummerer reaction of the mono-sulfoxide of p-bis(methylthio)-aromatic 1 is described. The reaction of 1 with (CF(3)CO)(2)O in CH(2)Cl(2) gave a mixture of the corresponding mono-Pummerer product 2, the bis-Pummerer product 3, and the bis-sulfide 4 in an n:1:1 ratio (n >/= 2). The 1:1 formation of 3 and 4 indicates an intermolecular interaction between sulfur atoms. The reaction with the deuterium-labeled 1-d(3)() showed that the formation of 2 occurs at the sulfenyl as well as sulfinyl groups in 1a-d(3)()-1d-d(3)(), in which the product ratio of 2-d(3)():2-d(2)() is in the range of 3.5-10. On the other hand, the Pummerer reaction of 1e-d(3)() occurred preferably at the sulfinyl group in a usual manner. The reaction of a 1:1 mixture of the bis-sulfide 4 and the bis-sulfoxide 5 with (CF(3)CO)(2)O also gave 2, 3, and 4 in a ratio similar to that for the reaction of 1. The mechanism in the present remote Pummerer reactions is discussed in light of an intermolecular through-space interaction between the sulfonium and sulfenyl sulfur atoms, and a dithia dication dimer B and/or a bis(dithia dication) cyclic dimer C are proposed as intermediates.
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http://dx.doi.org/10.1021/jo982377hDOI Listing
April 1999
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