Interfacial Mechanophore Activation Using Laser-Induced Stress Waves

A new methodology is developed to activate and characterize mechanochemical transformations at a solid interface. Maleimide–anthracene mechanophores covalently anchored at a fused silica–polymer interface are activated using laser-induced stress waves. Spallation-induced mechanophore activation is observed above a threshold activation stress of 149 MPa. The retro [4+2] cycloaddition reaction is confirmed by fluorescence microscopy, XPS, and ToF-SIMS measurements. Control experiments with specimens in which the mechanophore is not covalently attached to the polymer layer exhibit no activation. In contrast to activation in solution or bulk polymers, whereby a proportional increase in mechanophore activity is observed with applied stress, interfacial activation occurs collectively with spallation of the polymer film

Spatially Selective and Density-Controlled Activation of Interfacial Mechanophores

Mechanically sensitive molecules known as mechanophores have recently attracted much interest due to the need for mechanoresponsive materials. Maleimide–anthracene mechanophores located at the interface between poly(glycidyl methacrylate) (PGMA) polymer brushes and Si wafer surfaces were activated locally using atomic force microscopy (AFM) probes to deliver mechanical stimulation. Each individual maleimide–anthracene mechanophore exhibits binary behavior: undergoing a retro-[4 + 2] cycloaddition reaction under high load to form a surface-bound anthracene moiety and free PGMA or remaining unchanged if the load falls below the activation threshold. In the context of nanolithography, this behavior allows the high spatial selectivity required for the design and production of complex and hierarchical patterns with nanometer precision. The high spatial precision and control reported in this work brings us closer to molecular level programming of surface chemistry, with promising applications such as 3D nanoprinting, production of coatings, and composite materials that require nanopatterning or texture control as well as nanodevices and sensors for measuring mechanical stress and damage in situ

Interfacial Mechanophore Activation Using Laser-Induced Stress Waves

A new methodology is developed to activate and characterize mechanochemical transformations at a solid interface. Maleimide–anthracene mechanophores covalently anchored at a fused silica–polymer interface are activated using laser-induced stress waves. Spallation-induced mechanophore activation is observed above a threshold activation stress of 149 MPa. The retro [4+2] cycloaddition reaction is confirmed by fluorescence microscopy, XPS, and ToF-SIMS measurements. Control experiments with specimens in which the mechanophore is not covalently attached to the polymer layer exhibit no activation. In contrast to activation in solution or bulk polymers, whereby a proportional increase in mechanophore activity is observed with applied stress, interfacial activation occurs collectively with spallation of the polymer film

Spatially Selective and Density-Controlled Activation of Interfacial Mechanophores

Mechanically sensitive molecules known as mechanophores have recently attracted much interest due to the need for mechanoresponsive materials. Maleimide–anthracene mechanophores located at the interface between poly(glycidyl methacrylate) (PGMA) polymer brushes and Si wafer surfaces were activated locally using atomic force microscopy (AFM) probes to deliver mechanical stimulation. Each individual maleimide–anthracene mechanophore exhibits binary behavior: undergoing a retro-[4 + 2] cycloaddition reaction under high load to form a surface-bound anthracene moiety and free PGMA or remaining unchanged if the load falls below the activation threshold. In the context of nanolithography, this behavior allows the high spatial selectivity required for the design and production of complex and hierarchical patterns with nanometer precision. The high spatial precision and control reported in this work brings us closer to molecular level programming of surface chemistry, with promising applications such as 3D nanoprinting, production of coatings, and composite materials that require nanopatterning or texture control as well as nanodevices and sensors for measuring mechanical stress and damage in situ

Impact of experience of psychiatrists and psychiatry residents regarding electronic communication and social networking on internet use patterns: a questionnaire survey for developing e-professionalism in South Korea.

BACKGROUND: The development of technology, novel communication, and social networking can positively or negatively affect the therapeutic alliance between patients and psychiatrists. We conducted this study to identify Internet use patterns of psychiatrists and psychiatry residents in South Korea and to provide basic data for developing e-professionalism. METHODS: In this questionnaire survey included a total of 250 participants, of which 195 (78%) completed the questionnaire. Questions included demographics, use of email, web searches, personal and professional use of websites and social networking, and negative and positive experiences of electronic communication and social networking. We confirmed the correlation between experience and use patterns of psychiatrists electronic communication and social networking. RESULTS: A total of 129 participants (66.2%) reported that they posted their personal or professional content online, 112 (57.9%) had received patients requests through electronic communication or social networking, and 120 (61.4%) had communicated with patients via electronic communication or social networking. In total, 170 participants (87.2%) reported that they were worried about the negative consequences of using electronic communication and social networking, and 180 (92.3%) indicated they were not educated about electronic communication or social networking. CONCLUSION: In order to reduce the negative effects of electronic communication and social networking, we need guidelines that are appropriate for the situation in South Korea. Furthermore, future research will need to identify and suggest solutions for negative experiences of electronic communication and social networking that may affect the relationship between patients and physicians

Impact of experience of psychiatrists and psychiatry residents regarding electronic communication and social networking on internet use patterns: a questionnaire survey for developing e-professionalism in South Korea.

BACKGROUND:The development of technology, novel communication, and social networking can positively or negatively affect the therapeutic alliance between patients and psychiatrists. We conducted this study to identify Internet use patterns of psychiatrists and psychiatry residents in South Korea and to provide basic data for developing e-professionalism. METHODS:In this questionnaire survey included a total of 250 participants, of which 195 (78%) completed the questionnaire. Questions included demographics, use of email, web searches, personal and professional use of websites and social networking, and negative and positive experiences of electronic communication and social networking. We confirmed the correlation between experience and use patterns of psychiatrists' electronic communication and social networking. RESULTS:A total of 129 participants (66.2%) reported that they posted their personal or professional content online, 112 (57.9%) had received patients' requests through electronic communication or social networking, and 120 (61.4%) had communicated with patients via electronic communication or social networking. In total, 170 participants (87.2%) reported that they were worried about the negative consequences of using electronic communication and social networking, and 180 (92.3%) indicated they were not educated about electronic communication or social networking. CONCLUSION:In order to reduce the negative effects of electronic communication and social networking, we need guidelines that are appropriate for the situation in South Korea. Furthermore, future research will need to identify and suggest solutions for negative experiences of electronic communication and social networking that may affect the relationship between patients and physicians

Decreased cerebral blood flow of the right anterior cingulate cortex in long-term and short-term abstinent methamphetamine users

BACKGROUND: The aim of the current study was to explore changes of relative regional cerebral blood flow (rCBF) in short-term and long-term abstinent methamphetamine (MA) users. METHODS: Relative rCBF in 40 abstinent MA users and 23 healthy comparison subjects was compared by the technetium-99m-hexamethyl-propylene amine oxime ((99m)Tc-HMPAO) single photon emission computed tomography (SPECT). Relative rCBF in areas that were found to differ significantly was also compared in groups of MA users with short-term (or=6 months) abstinence. RESULTS: MA users showed decreased relative rCBF in the right anterior cingulate cortex (Brodmann area 32) relative to healthy comparison subjects. Long-term abstinent MA users had significantly greater rCBF than short-term abstinent MA users. CONCLUSIONS: We report that abstinent MA users have decreased rCBF in the anterior cingulate cortex with smaller relative decreases in subjects with prolonged abstinence

Frontal glucose hypometabolism in abstinent methamphetamine users

Changes in relative regional cerebral glucose metabolism (rCMRglc) and their potential gender differences in abstinent methamphetamine (MA) users were explored. Relative rCMRglc, as measured by (18)F-fluorodeoxyglucose positron emission tomography, and frontal executive functions, as assessed by Wisconsin card sorting test (WCST), were compared between 35 abstinent MA users and 21 healthy comparison subjects. In addition, male and female MA users and their gender-matched comparison subjects were compared to investigate potential gender differences. MA users had lower rCMRglc levels in the right superior frontal white matter and more perseveration and nonperseveration errors in the WCST, relative to healthy comparison subjects. Relative rCMRglc in the frontal white matter correlated with number of errors in the WCST in MA users. In the subanalysis for gender differences, lower rCMRglc in the frontal white matter and more errors in the WCST were found only in male MA users, not in female MA users, relative to their gender-matched comparison subjects. The current findings suggest that MA use causes persistent hypometabolism in the frontal white matter and impairment in frontal executive function. Our findings also suggest that the neurotoxic effect of MA on frontal lobes of the brain might be more prominent in men than in women

Decreased blood flow of temporal regions of the brain in subjects with panic disorder

OBJECT: The purpose of the current study was to investigate alterations of regional cerebral blood flow (rCBF) in subjects with panic disorder. METHODS: Twenty-two subjects with panic disorder who were under psychotropic medications and 25 age and gender-matched healthy comparison subjects were assessed regarding the rCBF of using Tc-99m-hexamethyl propylenamino oxime single photon emission tomography (SPECT). Using statistical parametric mapping, the rCBF was compared between panic disorder and healthy comparison groups. RESULTS: Decreased rCBF flow in right superior temporal lobe was observed in subjects with panic disorder (p<0.05 after correction for multiple comparisons). The rCBF in right superior temporal gyrus negatively correlated with the duration of illness, scores of panic disorder severity scale (PDSS), Hamilton anxiety rating scale (HARS) and Zung self-rating anxiety scale (Z-SAS). CONCLUSION: We report that there is a decreased cerebral blood flow of temporal regions of the brain in panic disorder and that this decrease may, in part, reflect the clinical severity of panic disorder