Label-free human chorionic gonadotropin detection at picogram levels using oriented antibodies bound to graphene screen-printed electrodes

Human chorionic gonadotropin (hCG) is a key diagnostic marker of pregnancy and an important biomarker for cancers in the prostate, ovaries and bladder and therefore of great importance in diagnosis. For this purpose, a new immunosensor of screen-printed electrodes (SPEs) is presented here. The device was fabricated by introducing a polyaniline (PANI) conductive layer, via in situ electropolymerization of aniline, onto a screen-printed graphene support. The PANI-coated graphene acts as the working electrode of a three terminal electrochemical sensor. The working electrode is functionalised with anti-hCG, by means of a simple process that enabled oriented antibody binding to the PANI layer. The antibody was attached to PANI following activation of the –COOH group at the Fc terminal. Functionalisation of the electrode was analysed and optimized using Electrochemical Impedance Spectroscopy (EIS). Chemical modification of the surface was characterised using Fourier transform infrared, and Raman spectroscopy with confocal microscopy. The graphene–SPE–PANI devices displayed linear responses to hCG in EIS assays from 0.001 to 50 ng mL−1 in real urine, with a detection limit of 0.286 pg mL−1. High selectivity was observed with respect to the presence of the constituent components of urine (urea, creatinine, magnesium chloride, calcium chloride, sodium dihydrogen phosphate, ammonium chloride, potassium sulphate and sodium chloride) at their normal levels, with a negligible sensor response to these chemicals. Successful detection of hCG was also achieved in spiked samples of real urine from a pregnant woman. The immunosensor developed is a promising tool for point-of-care detection of hCG, due to its excellent detection capability, simplicity of fabrication, low-cost, high sensitivity and selectivity.

Gaining a better understanding of how Outward Bound Western Canada course outcomes are achieved : a research study /

This study examined how Outward Bound Western Canada (OBWC) course outcomes are achieved by exploring the relationships among course components, students' characteristics, and course outcomes. OBWC is a wilderness-based adventure education organization that helps students achieve outcomes such as increased self-awareness, self-confidence, motivation, interpersonal skills, concern for others, and concern for the environment. This study explored the ways in which the various components of courses and the characteristics of students contribute to determining the outcomes students experience as a result of their courses. The purpose of the study was to gain a better understanding of how OBWC course outcomes are achieved in order to strengthen adventure education theory, enhance practice at OBWC and other adventure education organizations, and provide a foundation for further research on this topic. As an interpretive case study, this study sought to describe how OBWC course outcomes are achieved and to provide interpretations of the research findings. Data was gathered from OBWC students and instructors using the quantitative and qualitative data collection techniques of questionnaire, interview, and observation. Data collected from 98 participants ensured a considerable breadth to the study, while interviews with a number of participants also enabled the collection of in-depth data. Analysis and triangulation of the data from the various sources allowed discernment of the research findings. A comprehensive and detailed picture of how course outcomes are achieved emerged from the findings. Twenty-nine course components were found to influence course outcomes, including various aspects of course activities, the physical environment, instructors, and the group. The findings indicated that certain course components were most influential in determining increases to students' self-awareness, self-confidence, self-reliance, self-esteem, self-concept, motivation, self-responsibility, interpersonal skills, concern for others, and concern for the environment. A number of course components were found to indirectly contribute to positive course outcomes by helping maximize the effectiveness of other components, by increasing students' motivation while on course, or by facilitating the processing and transference of new information. The findings also suggested that several course components either directly or indirectly affected course outcomes in negative ways. In addition, the gender, age, population, and expectations of students were found to play a role in determining the course outcomes they experienced and in determining which course components caused those outcomes. Interpretation of the findings resulted in the generation of research-based theory. The main theoretical argument derived from the results of the study was that course outcomes are influenced by a combination of course components and characteristics of students. More specifically, the theory generated by the study indicated that five groupings of factors contribute to course outcomes, including course activities, the physical environment, instructors, the group, and students' characteristics. The study was considered in relation to existing adventure education literature and larger theoretical issues. The generated theory and research findings were then used to develop suggestions for improving practice at OBWC and other adventure education organizations, as well as for enhancing future research studies.

Enhancing personal effectiveness : the impacts of Costa Rica Outward Bound on students in an independent school in southwestern Ontario

This project examines students in a private school in southwestern Ontario on a 17 -day Costa Rica Outward Bound Rainforest multielement course. The study attempted to discover whether voluntary teenage participants could increase their self-perceptions of life effectiveness by participating in a 17-day expedition. A total of9 students participated in the study. The experimental design that was implemented was a mixed methods design. Participants filled in a Life Effectiveness Questionnaire (LEQ) at four predesignated times during the study. These time intervals occurred (a) before the trip commenced, (b) the first day of the trip, ( c) the last day of the trip, and (d) 1 month after the trip ended. Fieldnotes and recordings from informal group debriefing sessions were also used to gather information. Data collected in this study were analyzed in a variety of ways by the researcher. Analyses that were run on the data included the Friedman test for covariance, means, medians, and the Wilcoxon Pairs Test. The questionnaires were analyzed quantitatively, and the fieldnotes were analyzed qualitatively. Nonparametric statistical analysis was implemented as a result of the small group size of participants. Both sets of data were grouped and discussed according to similarities and differences. The data indicate that voluntary teenage participants experience significant changes over time in the areas of time management, social competency, emotional control, active initiative, and self-confidence. The types of outcomes from this study illustrate that Outward Bound-type opportunities should be offered to teenagers in Ontario schools as a means to bring about self-development.

Some Implications of the Zero Lower Bound on Interest Rates for the Term Structure and Monetary Policy

In an economy where cash can be stored costlessly (in nominal terms), the nominal interest rate is bounded below by zero. This paper derives the implications of this nonnegativity constraint for the term structure and shows that it induces a nonlinear and convex relation between short- and long-term interest rates. As a result, the long-term rate responds asymmetrically to changes in the short-term rate, and by less than predicted by a benchmark linear model. In particular, a decrease in the short-term rate leads to a decrease in the long-term rate that is smaller in magnitude than the increase in the long-term rate associated with an increase in the short-term rate of the same size. Up to the extent that monetary policy acts by affecting long-term rates through the term structure, its power is considerably reduced at low interest rates. The empirical predictions of the model are examined using data from Japan.

Studies on natural rubber-bound diphenylamine antioxidants

Diphenylamine was chemically attached to depolymerised natural rubber by photochemical reaction. The rubber-bound diphenylamine was characterised by TLC, HNMR, IR and TGA. The efficiency and permanence of the bound diphenylamine was compared with conventional amine type antioxidant in natural rubber vulcanizates. The rubber-bound diphenylamine was found to be less volatile and less extractable compared to the conventional antioxidant. The vulcanizates showed improved ageing resistance in comparison to vulcanizates containing conventional antioxidant . Also, the presence of liquid rubber-bound diphenylamine reduces the amount of plasticiser required for compounding.

Studies on rubber bound antioxidants

Antioxidants were attached to hydroxy-terminated liquid natural rubber by modified Friedel-Crafts alkylation reaction using anhydrous zinc chloride as catalyst. The rubber bound antioxidants were found to be less volatile and less extractable compared to conventional antioxidants. The bound antioxidants were tried both in latex compounds and dry rubber compounds. The vulcanizates showed improved ageing resistance compared to vulcanizates based on conventional antioxidants.

Studies on Natural Rubber Bound Para -Phenylenediamine Antioxidants in NBR

Para-phenylenediamine (PD) was chemically attached to depolymerized natural rubber by a photochemical reaction . The rubber bound PD was characterized by TLC, 1H-NMR, IR, and TGA. The efficiency and permanence of the bound PD were compared with conventional antioxidants in NBR vulcanizates . The rubber bound PD was found to be less volatile and more resistant to water and oil extraction . The vulcanizates showed improved aging resistance in comparison to vulcanizates containing conventional antioxidants. The liquid rubber bound antioxidant reduces the amount of plasticizer required for compounding

New oligomer-bound antioxidants for improved flex crack resistance and ozone resistance

New oligomer-bound antioxidants have been prepared by condensation reaction. The efficiency and permanence of these oligomer- bound paraphenylene diamines as antioxidants has been compared with conventional amine type antioxidants in NR, SBR, IIR and NBR and in elastomer blends like NR/BR and NR/SBR. The oligomer-bound antioxidants are found to impart improved ozone, flex resistance and mechanical properties to the vulcanizates of NR, SBR, IIR and NBR and to blends of NR/BR and NR/ SBR in comparison with those containing conventional antioxidants.

Synthesis and Characterization of Chlorinated Paraffin Wax-Bound Paraphenylenediamine Antioxidant and ItsApplication in Natural Rubber

ABSTRACT: p-Phenylenediamine was chemically attached to low molecular weight chlorinated paraffin wax. The polymer-bound p-phenylenediamine was characterized by vapor-phase osmometry (VPO), proton magnetic resonance spectroscopy ('H-NMR), infrared spectroscopy (IR), and thermogravimetric analysis (TGA). The efficiency and permanence of the polymer-bound p-phenylenediamine as an antioxidant was compared with a conventional amine-type antioxidant in natural rubber vulcanizates. The vulcanizates showed improved aging resistance in comparison to vulcanizates containing a conventional antioxidant. The presence of liquid polymer-bound p-phenylenediamine also reduces the amount of the plasticizer required for compounding.

Preparation and Characterisation of Novel Polymer Bound Phenolic Antioxidants and Its Use in Natural Rubber

ABSTRACT: Phenol was chemically attached to low molecular weight chlorinated polyisobutylene and stearic acid respectively. These phenolic antioxidants were characterised by IR, 1H NMR and TGA. The efficiency and permanence of these bound antioxidants were compared with conventional antioxidants in natural rubber vulcanisates. The vulcanisates showed comparable ageing resistance in comparison to vulcanisates containing conventional antioxidants. The presence of liquid polymer bound phenol reduce the amount of plasticiser required for compounding.

Synthesis,Characterisation and Uses of Polymer-bound Antioxidants

Department of Polymer Science and Rubber Technology,Cochin University of Science and Technology

Studies on Pseudoscalar Meson Bound States and Semileptonic Decays in a Relativistic Potential Model

In this thesis quark-antiquark bound states are considered using a relativistic two-body equation for Dirac particles. The mass spectrum of mesons includes bound states involving two heavy quarks or one heavy and one light quark. In order to analyse these states within a unified formalism, it is desirable to have a two-fermion equation that limits to one body Dirac equation with a static interaction for the light quark when the other particle's mass tends to infinity. A suitable two-body equation has been developed by Mandelzweig and Wallace. This equation is solved in momentum space and is used to describe the complete spectrum of mesons. The potential used in this work contains a short range one-gluon exchange interaction and a long range linear confining and constant potential terms. This model is used to investigate the decay processes of heavy mesons. Semileptonic decays are more tractable since there is no final state interactions between the leptons and hadrons that would otherwise complicate the situation. Studies on B and D meson decays are helpful to understand the nonperturbative strong interactions of heavy mesons, which in turn is useful to extract the details of weak interaction process. Calculation of form factors of these semileptonic decays of pseudo scalar mesons are also presented.

Continuum bound states as surface states of a finite periodic system

We discuss the relation between continuum bound states (CBSs) localized on a defect, and surface states of a finite periodic system. We model an experiment of Capasso et al. [F. Capasso, C. Sirtori, J. Faist, D. L. Sivco, S-N. G. Chu, and A. Y. Cho, Nature (London) 358, 565 (1992)] using the transfer-matrix method. We compute the rate for intrasubband transitions from the ground state to the CBS and derive a sum rule. Finally we show how to improve the confinement of a CBS while keeping the energy fixed.

Studies on Polymer Bound Antioxidants

The primary aim of this work has been to prepare efficient and cost effective polymer bound antioxidants by direct’ attachment of conventional antioxidants to a modified polymer. Due to the importance and easy availability of natural rubber in Kerala, it is proposed to make use of low molecular weight natural rubber as the polymer substrate for binding the antioxidant in most cases. The molecular weight of such low molecular weight natural rubber can be easily manipulated by varying the time of mastication, UV—irradiation etc. Further, the bound antioxidant may also get vulcanized during the vulcanization of the elastomer to which it is added, making the antioxidant non—volatile and non extractable. Several methods are proposed to be investigated for attaching the antioxidant to the low molecular weight natural rubber such as modified Friedel-Craft's alkylation reaction, binding during UV—irradiation, binding during aggressive mastication etc. The efficiency of such rubber bound antioxidants is proposed to be compared with that of conventional antioxidants in terms of volatility, extractability in solvents, ageing resistance etc. Naturally occuring antioxidants such as cardanol, are also proposed to be modified by binding them to low molecular weight natural rubber. The study is undertaken with the intention of generating a class of bound antioxidants which can be used in elastomers for aggressive and long term application.