Carbon nanostructure based electrodes for high efficiency dye sensitized solar cell

Synthesis and functionalization of large-area graphene and its structural, electrical and electrochemical properties has been investigated. First, the graphene films, grown by thermal chemical vapor deposition (CVD), contain three to five atomic layers of graphene, as confirmed by Raman spectroscopy and high-resolution transmission electron microscopy. Furthermore, the graphene film is treated with CF4 reactive-ion plasma to dope fluorine ions into graphene lattice as confirmed by X-ray photoelectron spectroscopy (XPS) and UV-photoemission spectroscopy (UPS). Electrochemical characterization reveals that the catalytic activity of graphene for iodine reduction enhanced with increasing plasma treatment time, which is attributed to increase in catalytic sites of graphene for charge transfer. The fluorinated graphene is characterized as a counter-electrode (CE) in a dye-sensitized solar cell (DSSC) which shows ~ 2.56% photon to electron conversion efficiency with ~11 mAcm−2 current density. Second, the large scale graphene film is covalently functionalized with HNO3 for high efficiency electro-catalytic electrode for DSSC. The XPS and UPS confirm the covalent attachment of C-OH, C(O)OH and NO3- moieties with carbon atoms through sp2-sp3 hybridization and Fermi level shift of graphene occurs under different doping concentrations, respectively. Finally, CoS-implanted graphene (G-CoS) film was prepared using CVD followed by SILAR method. The G-CoS electro-catalytic electrodes are characterized in a DSSC CE and is found to be highly electro-catalytic towards iodine reduction with low charge transfer resistance (Rct ~5.05 Ωcm 2) and high exchange current density (J0~2.50 mAcm -2). The improved performance compared to the pristine graphene is attributed to the increased number of active catalytic sites of G-CoS and highly conducting path of graphene. We also studied the synthesis and characterization of graphene-carbon nanotube (CNT) hybrid film consisting of graphene supported by vertical CNTs on a Si substrate. The hybrid film is inverted and transferred to flexible substrates for its application in flexible electronics, demonstrating a distinguishable variation of electrical conductivity for both tension and compression. Furthermore, both turn-on field and total emission current was found to depend strongly on the bending radius of the film and were found to vary in ranges of 0.8 - 3.1 V/μm and 4.2 - 0.4 mA, respectively.

The influence of weak parental and peer attachment on academic achievement among late adolescent college students

The current study examined the influence of weak parental and peer attachment on academic achievement among late adolescent college students. In previous research, weak attachment to parents and/or peers had been found to have an adverse influence on the academic success of college students. This study also examined the potential moderating influence of several cognitive and non-cognitive psychosocial variables that might act as protective factors for weakly attached students and, therefore, enhance their academic competence. Data regarding attachment, cognitive variables, and non-cognitive variables were collected using several self-report measures. The multi-ethnic sample of students in this study (n = 357) attended an urban university. Students were classified into one of nine parental-peer attachment groups (e.g., Low-Low, Medium-Medium, High-High). Attachment groups were compared in terms of cognitive and non-cognitive variables. Contrary to the hypothesis, no statistically significant academic achievement differences were revealed for the group of college students who perceived themselves to be weakly attached to both parents and peers. Analysis of variance (ANOVA) identified the High-High group to be significantly different in terms of academic outcome variables from the other eight groups while the Low-Low group had significantly lower levels of non-cognitive variables than several of the other attachment groups. Hierarchical multiple regression analyses revealed that cognitive variables accounted for significant amounts of variance in academic outcomes and that several non-cognitive variables were significant predictors of scholastic competence. Correlational analyses revealed that parental and peer attachment were positively correlated with several cognitive and non-cognitive variables but neither was significantly correlated with self-reported college GPA. In general, the findings do not provide support for a main effect of weak attachment to parents and peers upon academic adversity among college students. Results suggest that both cognitive variables and non-cognitive variables may moderate academic risk due to weak attachment to parents and peers. Descriptive within group analyses of the Low-Low group revealed a heterogeneous group of students with regards to academic outcomes and scores on non-cognitive measures. Gender and ethnic differences were found for attachment status but not for cognitive or non-cognitive variables. Implications for interventions and suggestions for future research are presented. ^

Computational modeling of biodegradable starch based polymer composites

Purpose. The goal of this study is to improve the favorable molecular interactions between starch and PPC by addition of grafting monomers MA and ROM as compatibilizers, which would advance the mechanical properties of starch/PPC composites. ^ Methodology. DFT and semi-empirical methods based calculations were performed on three systems: (a) starch/PPC, (b) starch/PPC-MA, and (c) starch-ROM/PPC. Theoretical computations involved the determination of optimal geometries, binding-energies and vibrational frequencies of the blended polymers. ^ Findings. Calculations performed on five starch/PPC composites revealed hydrogen bond formation as the driving force behind stable composite formation, also confirmed by the negative relative energies of the composites indicating the existence of binding forces between the constituent co-polymers. The interaction between starch and PPC is also confirmed by the computed decrease in stretching CO and OH group frequencies participating in hydrogen bond formation, which agree qualitatively with the experimental values. ^ A three-step mechanism of grafting MA on PPC was proposed to improve the compatibility of PPC with starch. Nine types of 'blends' produced by covalent bond formation between starch and MA-grafted PPC were found to be energetically stable, with blends involving MA grafted at the 'B' and 'C' positions of PPC indicating a binding-energy increase of 6.8 and 6.2 kcal/mol, respectively, as compared to the non-grafted starch/PPC composites. A similar increase in binding-energies was also observed for three types of 'composites' formed by hydrogen bond formation between starch and MA-grafted PPC. ^ Next, grafting of ROM on starch and subsequent blend formation with PPC was studied. All four types of blends formed by the reaction of ROM-grafted starch with PPC were found to be more energetically stable as compared to the starch/PPC composite and starch/PPC-MA composites and blends. A blend of PPC and ROM grafted at the ' a&d12; ' position on amylose exhibited a maximal increase of 17.1 kcal/mol as compared with the starch/PPC-MA blend. ^ Conclusions. ROM was found to be a more effective compatibilizer in improving the favorable interactions between starch and PPC as compared to MA. The ' a&d12; ' position was found to be the most favorable attachment point of ROM to amylose for stable blend formation with PPC.^

Hispanic adolescents with severe substance abuse problems: Parental involvement, acculturation-related factors, and attachment

The main objective of the study was to investigate the relationship between parent-related, acculturation-related, and substance use-related variables found within individual, familial/parental, peer and school adolescent ecological domains, in a clinical sample (i.e. adolescents who met criteria for a Diagnostic Statistical Manual-IV [DSMIV] clinical diagnosis of substance abuse/dependence) of Hispanic adolescents from Miami, Florida. ^ The sample for this study consisted of 94 adolescent-mother pairs. The adolescent sample was 65% male, and 35% female, with a mean age of 15 years. More than half of the adolescents were born in the United States (60%) and had resided in the U.S. for an average of 12 years; 80% of the caregivers (primarily mothers) were foreign-born and lived in the U.S. for an average of 21 years. ^ Correlation and hierarchical regression were used to answer the research questions. The findings indicate that the hypothesized model and corresponding anticipated effect of the relationship between parental school and peer involvement on adolescents’ frequency of alcohol, marijuana and cocaine use was not supported by the data. Parental “acculturation-related” variables did not explain any of the variance in adolescent substance use frequency in this sample. Mediation and moderation models were not supported either. However, some interesting relationships were found: ^ The larger the acculturation gap, the lower the parental involvement in school tended to be (r = -.21, p < .05). Adolescents who experienced a greater acculturation gap with their parents (-.81, p >.01) had an earlier onset of marijuana (-.33, p < .01) and cocaine use (r = -.24, p <.01). The less acculturated parents experienced more parenting stress (r = -.31, p = < .01). Attachment was positively associated with parental peer involvement (r = .24, p < .05) and inversely associated with parenting acculturative stress (r = -.24, p < .05). Attachment was also positively associated with marijuana (r = .39, p < .01) and cocaine use (r = .33, p < .01). Adolescent males reported being more attached to their mothers when compared to adolescent females (r = .22, p >.05), they also reported using marijuana more frequently than females (.21, p >.05). ^

The effects of peer teaching of infant massage on general elf-efficacy and mother infant attachment among mothers in a residential rehabilitation facility for drug addiction and substance abuse

Approximately 200 million people, 5% aged 15-64 worldwide are illicit drug or substance abusers (World Drug Report, 2006). Between 2002 and 2005, an average of 8.2% of 12 year olds and older in the Miami, Fort Lauderdale metropolitan areas used illicit drugs (SAMHSA, 2007). Eight percent of pregnant women, aged 15 to 25, were more likely to have used illicit drugs during pregnancy than pregnant women aged 26 to 44. Alcohol use was 9.8% and cigarette use was 18% for pregnant women aged 15 to 44 (SAMHSA, 2005). Approximately a quarter of annual birth defects are attributed to the exposure of drugs or substance abuse in utero (General Accounting Office, 1991). Physical, psychological and emotional challenges may be present for the illicit drug/substance abuse (ID/SA) mother and infant placing them at a disadvantage early in their relationship (Shonkoff & Marshall, 1990). Mothers with low self efficacy have insecurely attached infants (Donovan, Leavitt, & Walsh, 1987). As the ID/SA mother struggles with wanting to be a good parent, education is needed to help her care for her infant. In this experimental study residential rehabilitating ID/SA mothers peer taught infant massage. Massage builds bonding/attachment between mother and infant (Reese & Storm, 2008) and peer teaching is effective because participants have faced similar challenges and speak the same language (Boud, Cohen, & Sampson 2001). Quantitative data were collected using the General Self-Efficacy and Maternal Attachment Inventory-Revised Scale before and after the 4-week intervention program. A reported result of this study was that empowering ID/SA mothers increased their self-efficacy, which in turn allowed the mothers to tackle challenges encountered and created feelings of being a fit mother to their infants. This research contributes to the existing database promoting evidence-based practice in drug rehabilitation centers. Healthcare personnel, such as nurse educators and maternal-child health practitioners, can develop programs in drug rehabilitation centers that cultivate an environment where the ID/SA rehabilitating mothers can peer teach each other, while creating a support system. Using infant massage as a therapeutic tool can develop a healthy infant and nurture a more positive relationship between mother and infant.

Attachment Theory Shaping Adult Development: Impact on Mentoring Experiences

Mentoring is increasingly used for career and psychosocial development. Very few studies that have investigated the role of individual differences in mentoring relationships have addressed the attachment styles of mentors and protégés. The purpose of this study is to find the connections between attachment styles, adult development, and mentoring experiences.

Covalent protein adduction by drugs of abuse

Recreational abuse of the drugs cocaine, methamphetamine, and morphine continues to be prevalent in the United States of America and around the world. While numerous methods of detection exist for each drug, they are generally limited by the lifetime of the parent drug and its metabolites in the body. However, the covalent modification of endogenous proteins by these drugs of abuse may act as biomarkers of exposure and allow for extension of detection windows for these drugs beyond the lifetime of parent molecules or metabolites in the free fraction. Additionally, existence of covalently bound molecules arising from drug ingestion can offer insight into downstream toxicities associated with each of these drugs. This research investigated the metabolism of cocaine, methamphetamine, and morphine in common in vitro assay systems, specifically focusing on the generation of reactive intermediates and metabolites that have the potential to form covalent protein adducts. Results demonstrated the formation of covalent adduction products between biological cysteine thiols and reactive moieties on cocaine and morphine metabolites. Rigorous mass spectrometric analysis in conjunction with in vitro metabolic activation, pharmacogenetic reaction phenotyping, and computational modeling were utilized to characterize structures and mechanisms of formation for each resultant thiol adduction product. For cocaine, data collected demonstrated the formation of adduction products from a reactive arene epoxide intermediate, designating a novel metabolic pathway for cocaine. In the case of morphine, data expanded on known adduct-forming pathways using sensitive and selective analysis techniques, following the known reactive metabolite, morphinone, and a proposed novel metabolite, morphine quinone methide. Data collected in this study describe novel metabolic events for multiple important drugs of abuse, culminating in detection methods and mechanistic descriptors useful to both medical and forensic investigators when examining the toxicology associated with cocaine, methamphetamine, and morphine.

Covalent protein adduction of nitrogen mustards and related compounds

Chemical warfare agents continue to pose a global threat despite the efforts of the international community to prohibit their use in warfare. For this reason, improvement in the detection of these compounds remains of forensic interest. Protein adducts formed by the covalent modification of an electrophilic xenobiotic and a nucleophilic amino acid may provide a biomarker of exposure that is stable and specific to compounds of interest (such as chemical warfare agents), and have the capability to extend the window of detection further than the parent compound or circulating metabolites. This research investigated the formation of protein adducts of the nitrogen mustard chemical warfare agents mechlorethamine (HN-2) and tris(2-chloroethyl)amine (HN-3) to lysine and histidine residues found on the blood proteins hemoglobin and human serum albumin. Identified adducts were assessed for reproducibility and stability both in model peptide and whole protein assays. Specificity of these identified adducts was assessed using in vitro assays to metabolize common therapeutic drugs containing nitrogen mustard moieties. Results of the model peptide assays demonstrated that HN-2 and HN-3 were able to form stable adducts with lysine and histidine residues under physiological conditions. Results for whole protein assays identified three histidine adducts on hemoglobin, and three adducts (two lysine residues and one histidine residue) on human serum albumin that were previously unknown. These protein adducts were determined to be reproducible and stable at physiological conditions over a three-week analysis period. Results from the in vitro metabolic assays revealed that adducts formed by HN-2 and HN-3 are specific to these agents, as metabolized therapeutic drugs (chlorambucil, cyclophosphamide, and melphalan) did not form the same adducts on lysine or histidine residues as the previously identified adducts formed by HN-2 and HN-3. Results obtained from the model peptide and full protein work were enhanced by comparing experimental data to theoretical calculations for adduct formation, providing further confirmatory data. This project was successful in identifying and characterizing biomarkers of exposure to HN-2 and HN-3 that are specific and stable and which have the potential to be used for the forensic determination of exposure to these dangerous agents.

Looking At Residents’ Attitudes towards Spring Break Tourism in Texas through the Lens of Community Attachment

The growth of spring break tourism in many destinations has become problematic, predominantly due to the excessive behaviour of college students. This paper examines residents’ attitudes toward spring break tourism in South Padre Island (located in Texas, USA) through the lens of community attachment. By understanding the attitudes of residents of the host communities, tourism planners and policy-makers can create policies to shape the character of tourism according to the residents’ needs. The findings suggest that, at this point in time, community residents perceive that the benefits of spring break tourism benefits exceed its’ costs. Also, the short and intense season of spring break tourism allows residents to better deal with social costs.

Hispanic Adolescents With Severe Substance Abuse Issues: Parental Involvement, Acculturation-Related Factors and Attachment

The main objective of the study was to investigate the relationship between parent-related, acculturation-related, and substance use-related variables found within individual, familial/parental, peer and school adolescent ecological domains, in a clinical sample (i.e. adolescents who met criteria for a Diagnostic Statistical Manual-IV [DSM-IV] clinical diagnosis of substance abuse/dependence) of Hispanic adolescents from Miami, Florida. The sample for this study consisted of 94 adolescent-mother pairs. The adolescent sample was 65% male, and 35% female, with a mean age of 15 years. More than half of the adolescents were born in the United States (60%) and had resided in the U.S. for an average of 12 years; 80% of the caregivers (primarily mothers) were foreign-born and lived in the U.S. for an average of 21 years. Correlation and hierarchical regression were used to answer the research questions. The findings indicate that the hypothesized model and corresponding anticipated effect of the relationship between parental school and peer involvement on adolescents’ frequency of alcohol, marijuana and cocaine use was not supported by the data. Parental “acculturation-related” variables did not explain any of the variance in adolescent substance use frequency in this sample. Mediation and moderation models were not supported either. However, some interesting relationships were found: The larger the acculturation gap, the lower the parental involvement in school tended to be (r = -.21, p < .05). Adolescents who experienced a greater acculturation gap with their parents (-.81, p >.01) had an earlier onset of marijuana (-.33, p < .01) and cocaine use (r = -.24, p .05), they also reported using marijuana more frequently than females (.21, p >.05).

The Effects of Peer Teaching of Infant Massage on General Self-Efficacy and Mother Infant Attachment Among Mothers in a Residential Rehabilitation Facility for Drug Addiction and Substance Abuse

Approximately 200 million people, 5% aged 15-64 worldwide are illicit drug or substance abusers (World Drug Report, 2006). Between 2002 and 2005, an average of 8.2% of 12 year olds and older in the Miami, Fort Lauderdale metropolitan areas used illicit drugs (SAMHSA, 2007). Eight percent of pregnant women, aged 15 to 25, were more likely to have used illicit drugs during pregnancy than pregnant women aged 26 to 44. Alcohol use was 9.8% and cigarette use was 18% for pregnant women aged 15 to 44 (SAMHSA, 2005). Approximately a quarter of annual birth defects are attributed to the exposure of drugs or substance abuse in utero (General Accounting Office, 1991). Physical, psychological and emotional challenges may be present for the illicit drug/substance abuse (ID/SA) mother and infant placing them at a disadvantage early in their relationship (Shonkoff & Marshall, 1990). Mothers with low self efficacy have insecurely attached infants (Donovan, Leavitt, & Walsh, 1987). As the ID/SA mother struggles with wanting to be a good parent, education is needed to help her care for her infant. In this experimental study residential rehabilitating ID/SA mothers peer taught infant massage. Massage builds bonding/attachment between mother and infant (Reese & Storm, 2008) and peer teaching is effective because participants have faced similar challenges and speak the same language (Boud, Cohen, & Sampson 2001). Quantitative data were collected using the General Self-Efficacy and Maternal Attachment Inventory-Revised Scale before and after the 4-week intervention program. A reported result of this study was that empowering ID/SA mothers increased their self-efficacy, which in turn allowed the mothers to tackle challenges encountered and created feelings of being a fit mother to their infants. This research contributes to the existing database promoting evidence-based practice in drug rehabilitation centers. Healthcare personnel, such as nurse educators and maternal-child health practitioners, can develop programs in drug rehabilitation centers that cultivate an environment where the ID/SA rehabilitating mothers can peer teach each other, while creating a support system. Using infant massage as a therapeutic tool can develop a healthy infant and nurture a more positive relationship between mother and infant.

Maternal-Fetal Attachment and Health Behaviors among Women with HIV/AIDS

Background: Mothers with HIV often face personal and environmental risks for poor maternal health behaviors and infant neglect, even when HIV transmission to the infant was prevented. Maternal-fetal attachment (MFA), the pre-birth relationship of a woman with her fetus, may be the precursor to maternal caregiving. Using the strengths perspective in social work, which embeds MFA within a socio-ecological conceptual framework, it is hypothesized that high levels of maternal-fetal attachment may protect mothers and infants against poor maternal health behaviors. Objective: To assess whether MFA together with history of substance use, living marital status, planned pregnancy status, and timing of HIV diagnosis predict three desirable maternal health behaviors (pregnancy care, adherence to prenatal antiretroviral therapy–ART, and infant’s screening clinic care) among pregnant women with HIV/AIDS. Method: Prospective observation and hypothesis-testing multivariate analyses. Over 17 consecutive months, all eligible English- or Spanish-speaking pregnant women with HIV ( n = 110) were approached in the principal obstetric and screening clinics in Miami-Dade County, Florida at 24 weeks’ gestation; 82 agreed to enroll. During three data collection periods from enrollment until 16 weeks after childbirth (range: 16 to 32 weeks), participants reported on socio-demographic and predictor variables, MFA, and pregnancy care. Measures of adherence to ART and infant care were extracted from medical records. Findings: Sociodemographic, pregnancy, and HIV disease characteristics in this sample suggest changes in the makeup of HIV-infected pregnant women parallel to the evolution of the HIV epidemic in the USA over the past two decades. The MFA model predicted maternal health behaviors for pregnancy care (R2 = .37), with MFA, marital living status, and planned pregnancy status independently contributing ( = .50, = .28, = .23, respectively). It did not predict adherence to ART medication or infant care. Relevance: These findings provide the first focused evidence of the protective role of MFA against poor maternal health behaviors among pregnant women with HIV, in the presence of adverse life circumstances. Social desirability biases in some self-report measures may limit the findings. Suggestions are made for orienting future inquiry on maternal health behaviors during childbirth toward relationship and protection.

Covalent Protein Adduction by Drugs of Abuse

Recreational abuse of the drugs cocaine, methamphetamine, and morphine continues to be prevalent in the United States of America and around the world. While numerous methods of detection exist for each drug, they are generally limited by the lifetime of the parent drug and its metabolites in the body. However, the covalent modification of endogenous proteins by these drugs of abuse may act as biomarkers of exposure and allow for extension of detection windows for these drugs beyond the lifetime of parent molecules or metabolites in the free fraction. Additionally, existence of covalently bound molecules arising from drug ingestion can offer insight into downstream toxicities associated with each of these drugs. This research investigated the metabolism of cocaine, methamphetamine, and morphine in common in vitro assay systems, specifically focusing on the generation of reactive intermediates and metabolites that have the potential to form covalent protein adducts. Results demonstrated the formation of covalent adduction products between biological cysteine thiols and reactive moieties on cocaine and morphine metabolites. Rigorous mass spectrometric analysis in conjunction with in vitro metabolic activation, pharmacogenetic reaction phenotyping, and computational modeling were utilized to characterize structures and mechanisms of formation for each resultant thiol adduction product. For cocaine, data collected demonstrated the formation of adduction products from a reactive arene epoxide intermediate, designating a novel metabolic pathway for cocaine. In the case of morphine, data expanded on known adduct-forming pathways using sensitive and selective analysis techniques, following the known reactive metabolite, morphinone, and a proposed novel metabolite, morphine quinone methide. Data collected in this study describe novel metabolic events for multiple important drugs of abuse, culminating in detection methods and mechanistic descriptors useful to both medical and forensic investigators when examining the toxicology associated with cocaine, methamphetamine, and morphine.