81 research outputs found

    An Analytical Method for Detecting Toxic Metal Cations Using Cyclotriveratrylene Derivative Capped Gold Nanoparticles

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    Cyclotriveratrylene-oxime (CTV-oxime) derivatives that terminate with a dithiolate linker were synthesized enabling the supramolecular scaffold to adhere to gold nanoparticles (AuNPs) with the bowl-shaped cavity of the CTV scaffold exposed for utilization in host–guest chemistry. Exposure of these CTV functionalized AuNPs to varying concentrations of di- and trivalent metal cations resulted in the formation of large CTV-AuNP polymeric clusters and an accompanying a shift in the plasmon resonance. These interactions between the CTV-AuNPs and the metal cations in solution provides proof-of-concept that supramolecular functionalized AuNPs can be used as a simple and straightforward, on-site detection system for toxic metal cations in solution. The order of binding affinity of the metals studied based on observed Kd values is Cu2+ \u3e Zn2+ \u3e Pb2+ \u3e Hg2+ \u3e Eu3+ \u3e Cd2+

    Lyman Abbott: How Beecher Influenced Him

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    The Synthesis and Medicinal Chemical Study of Some Pyridazones

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    An examination of the literature revealed that the majority of pyridazines prepared were substituted in the three and six positions. Therefore, it appeared appropriate to prepare four and five substituted pyridazines

    Direct Patterning of a Cyclotriveratrylene Derivative for Directed Self-assembly of C60

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    A novel apex-modified cyclotriveratrylene (CTV) derivative with an attached thiolane-containing lipoic acid linker was directly patterned onto gold substrates via dip-pen nanolithography (DPN). The addition of a dithiolane-containing linker to the apex of CTV provides a molecule that can adhere to a gold surface with its bowl-shaped cavity directed away from the surface, thereby providing a surface-bound CTV host that can be used for the directed assembly of guest molecules. Subsequent exposure of these CTV microarrays to C60 in toluene resulted in the directed assembly of predesigned, spatially controlled, high-density microarrays of C60. The molecular recognition capabilities of this CTV template toward C60 provides proof-of-concept that supramolecular CTV scaffolds can be directly patterned onto surfaces providing a foundation for the development of organic electronic and optoelectronic materials

    Dimensi Employer Branding dan Website Perusahaan dan Dampaknya Terhadap Minat Melamar Pekerjaan (Studi terhdap Fresh Gradute Perguruan Tinggi di Palangka Raya)

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    Menentukan tempat kerja merupakan hal yang penting bagi calon karyawan. Tempat kerja yang sesuai keinginan akan mengurangi kecendrungan untuk melakukan turnover. Generasi milenial selain dikenal sebagai generasi yang paham teknologi, juga dikenal sebagai generasi yang berani mengambil risiko soal karir. Generasi ini cenderung mudah berpindah dari satu pekerjaan ke pekerjaan lainnya dalam rentang waktu singkat. Banyak penelitian mengatakan cara untuk menilai suatu perusahaan dengan melihat employer branding yang ditawarkan. Employer branding merupakan proses membangun keunikan identitas dan nilai perusahaan sehingga dapat membedakan perusahaan dengan kompetitornya. Employer branding memiliki dimensi-dimensi sebagai suatu nilai dari perusahaan guna menarik dan mempertahankan karyawannya. Dimensi-dimensi employer branding mencakup beberapa hal yang merujuk pada penelitin Obala (2017) dan Ninlsa (2019) di antaranya : nilai inovasi, nilai pengembangan, nilai sosial, nilai ekonomi dan nilai reputasi. Penelitian ini bertujuan untuk menguji pengaruh employer branding (nilai inovasi, pengembangan, sosial, ekonomi dan reputasi) dan website perusahaan terhadap minat melamar pekerjaan (fresh gradute perguruan tinggi Palangka Raya) dengan minat melamar pekerjaan sebagai variabel independen, dengan employer branding (nilai inovasi, pengembangan, sosial, ekonomi dan reputasi) dan website perusahaan sebagai variabel dependen. Responden penelitin ini adalah 160 dari berbagai perguruan tinggi Palangka Raya. Penelitian ini menggunakan teknik analisis regresi linier berganda dengan bantuan program spss. Hasil penelitian ini menunjukan bahwa dimensi employer branding (nilai inovasi, pengembangan, sosial, ekonomi dan reputasi) dan website perusahaan berpengaruh terhadap minat melamar pekerjaan (fresh gradute perguruan tinggi Palangka Raya)

    An investigation of the history and works of the Keiskamma Art Project

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    This research study focusses on how and why Carol Hofmeyr began the Keiskamma Art Project in Hamburg, Eastern Cape, as well as the development of the project’s infrastructure, history and detailed business practices and how it has evolved. A chronological detailed pictorial record has been drawn up of the major/monumental works it has produced, its achievements, awards and the accolades it has won. The recurrent narrative themes of HIV/AIDS, Nguni cattle, the Nongquawuse story, local birds, plants and fish which are also discussed. A comparable study, comparing the business practices of the Keiskamma Art Project with the research of Professor Ingrid Stevens on Morris & Co and five other successful, sustained South African Art Projects. Data has been tabulated in an effort to recognise the variances, similarities and differences in an effort to identify a “best practise” business model. Such a model may assist in the development of further art projects, so as to uplift other poverty stricken communities in South Africa. This research study focusses on how and why Carol Hofmeyr began the Keiskamma Art Project in Hamburg, Eastern Cape, as well as the development of the project’s infrastructure, history and detailed business practices and how it has evolved. A chronological detailed pictorial record has been drawn up of the major/monumental works it has produced, its achievements, awards and the accolades it has won. The recurrent narrative themes of HIV/AIDS, Nguni cattle, the Nongquawuse story, local birds, plants and fish which are also discussed. A comparable study, comparing the business practices of the Keiskamma Art Project with the research of Professor Ingrid Stevens on Morris & Co and five other successful, sustained South African Art Projects. Data has been tabulated in an effort to recognise the variances, similarities and differences in an effort to identify a “best practise” business model. Such a model may assist in the development of further art projects, so as to uplift other poverty-stricken communities in South Africa.This research study focusses on how and why Carol Hofmeyr began the Keiskamma Art Project in Hamburg, Eastern Cape, as well as the development of the project’s infrastructure, history and detailed business practices and how it has evolved. A chronological detailed pictorial record has been drawn up of the major/monumental works it has produced, its achievements, awards and the accolades it has won. The recurrent narrative themes of HIV/AIDS, Nguni cattle, the Nongquawuse story, local birds, plants and fish which are also discussed. A comparable study, comparing the business practices of the Keiskamma Art Project with the research of Professor Ingrid Stevens on Morris & Co and five other successful, sustained South African Art Projects. Data has been tabulated in an effort to recognise the variances, similarities and differences in an effort to identify a “best practise” business model. Such a model may assist in the development of further art projects, so as to uplift other poverty stricken communities in South Africa.This research study focusses on how and why Carol Hofmeyr began the Keiskamma Art Project in Hamburg, Eastern Cape, as well as the development of the project’s infrastructure, history and detailed business practices and how it has evolved. A chronological detailed pictorial record has been drawn up of the major/monumental works it has produced, its achievements, awards and the accolades it has won. The recurrent narrative themes of HIV/AIDS, Nguni cattle, the Nongquawuse story, local birds, plants and fish which are also discussed. A comparable study, comparing the business practices of the Keiskamma Art Project with the research of Professor Ingrid Stevens on Morris & Co and five other successful, sustained South African Art Projects. Data has been tabulated in an effort to recognise the variances, similarities and differences in an effort to identify a “best practise” business model. Such a model may assist in the development of further art projects, so as to uplift other poverty stricken communities in South Africa

    The Synthesis and Host-Guest Applications of Synthetic Receptor Molecules

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    Host-guest chemistry involves the complimentary binding between two molecules. Host molecules have been synthesized to bind negative, positive, and neutral molecules such as proteins and enzymes, and have been used as optical sensors, electrochemical sensors, supramolecular catalysts, and in the pharmaceutical industry as anti-cancer agents.1 The field of nanoscience has exploited guest-host interactions to create optical sensors with colloidal gold and Dip-Pen nanolithography technologies. Gold nanoparticles, have been functionalized with DNA, and have been developed as a selective colorimetric detection system, that upon binding turns the solution from a red to blue in color.2 Cyclotriveratrylene (CTV) 1 is a common supramolecular scaffold that has been previously employed in guest-host chemistry, and the construction of CTV involves the cyclic trimerization of veratryl alcohol via the veratryl cation.3 Due to the rigid bowl shaped structure of CTV, CTV has been shown to act as a host molecule for fullerene-C60.4 Lectin binding receptor proteins are a specific class of proteins found in bacteria, viruses, plants, and animals that can bind to complimentary carbohydrates. It is these lectins that are believed to be responsible for cell-cell interactions and the formation of biofilms in pathenogenic bacteria.5 P. aeruginosa is a pathenogenic bacterium, shown to have a high resistance to many antibiotics, which can form biofilms in human lung tissue, causing respiratory tract infections in patients with compromised immune systems.5 I will exploit guest-host interactions to create synthetic supramolecular and carbohydrate receptor molecules to that will be of use as biological sensing devices via self-assembled monolayers on solid surfaces and nanoparticle technologies

    Threat evaluation and jamming allocation

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    A threat evaluation and jamming allocation (TEJA) system is proposed and implemented in order to optimise the jamming strategy of a platform. This TEJA system accounts for the different effects of jamming techniques on threats and radar modes, the interaction between jamming techniques and channels, the relative frequency and bandwidth used by threats, the uncertainty of the threat environment, and models the progression of threats through various radar modes from initial search to final guidance. Performance of the TEJA system is evaluated for a complex mission which considers a platform with two jammers penetrating an area with ten threats. The TEJA system is shown to be computationally efficient by using an exhaustive search to determine the optimum jamming strategy. The developed jamming strategy allows the platform to survive a mission despite its complexity.http://digital-library.theiet.org/content/journals/iet-rsnhb2017Electrical, Electronic and Computer Engineerin

    Attempted Resolution and Racemization of Beckmann‐Derived CTV‐Lactam and the Use of Chirabite‐AR¼ to Determine the Optical Purity of the Supramolecular Scaffold

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    Chirabite‐AR was employed to differentiate enantiomers of the axially chiral cyclotriveratrylene (CTV)‐derived macrocyclic lactam with baseline separation of most of the proton NMR resonances enabling enantiomeric purity determination of this supramolecular scaffold. Attachment of menthyloxy acetic acid as a chiral auxiliary to the CTV‐Beckmann derived lactam afforded diastereomers that were enriched to a ratio of 87:13, as confirmed by both 1H NMR and single‐crystal X‐ray diffraction. Basic hydrolysis of the enriched diastereomeric mixture proceeded with rapid bowl inversion to yield racemic CTV‐lactam as confirmed by Chirabite‐AR NMR analysis. Density functional theory (DFT) calculations (M06 2X/6‐31G*) were performed on the crown and saddle conformers of the CTV‐lactam
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