Preparation of constant viscosity natural rubber with mercaptan

Constant viscosity natural rubber has been prepared using mercaptan. The accelerated storage tests indicate that the storage hardening phenomenon of natural rubber can be inhibited by mercaptan. The amount of mercaptan (2-mercaptobenzothiazole) of 0.14 phr is sufficient to prepare constant viscosity natural rubber and the storage hardening numbers of constant viscosity NR in both Mooney viscosity and Wallace plasticity are less than 4. The processing properties and anti-oxidative behavior of CV-NR can be improved, although the mechanical properties of vulcanizates decreased slightly as compared to those of natural rubber. The results further support the hypothesis that the abnormal groups in natural rubber molecules are aldehyde groups and are responsible for the hardening of natural rubber.

Active content for preparation of teaching materials

Teaching materials such as study guides have implicit structure that can be exploited to explicitly assist in the learning and teaching process. Document technologies specific to the teaching context generate visible structures and linkages in a consistent manner across multiple course materials. We describe techniques that:

• Create, manage and validate links between the learning objectives, content related to each objective and corresponding assessment task.

• Explicitly present relationships between concepts, as a concept map, related to unit content and external study resources.

• Treat various study resources (study guide, presentation slides) as consistent views.

• Facilitate the use of external media to support multiple modalities.

The process creates teaching content as a single master document which is annotated to: identify learning outcomes associated with topics and exercises, relationships between concepts covered, references to external resources and media, as well as summary points and keywords. Different views of this master document produce the range of course documentation.

Examples of documents include: a study guide with learning outcomes linked to content, concept maps providing a graphical view of key relationships, and presentation slides that generate visual mnemonics for important topics.

While this structure simplifies formatting of learning materials it also offers additional benefits to the teacher. Reports are generated showing that all outcomes are covered and assessed.   Explicitly annotating and visualizing concepts allows the lecturer to ensure that all elements fall within a single scaffold. Simplified access to external media encourages alternative presentation modalities and produces presentations that are easily adapted to new themes.

Preparation of nanoparticles by crosslinking folate conjugated chitosan with vanillin and its characterization

Functionalized chitosan (CS) were widely used as drug delivery system in the chemotherapy of various disease. In this work, folate (FA) was conjugated into chitosan molecular as targeting ligand based on Schiff reaction between –NH₂ group of CS and –COOH group of FA. And nanoparticles were made by emulsion method with vanillin novel cross-linking agent. The FA modified CS and its nanoparticles were characterized by Fourier transform spectroscopy (FT-IR), scanning electron microscope (SEM) and Zeta potential. SEM results confirmed the nanoparticles made from FA-CS conjugate were spherical in shape and were about 100 nm in size. Zeta potential analysis revealed that the nanoparticles were negatively charged with charge density of -7.73mV.

Disorder and the body of drugs : addiction, consumption, control, and city space

Different cultures and the specific culture manifested within them are intrinsically linked to addiction in a complex fashion which has a long history. For important thinkers, such as Nietzsche, addiction actually embodies human culture, rendering addiction and culture inseparable. This is clearly seen within the Western world’s addiction to the consumption of material goods and the damage that results.

Utopia has often become dystopia. Not only is an understanding of addiction key to understanding culture but to an understanding of the very act thinking itself and the way of being in the world. Addiction raises key philosophical questions, such as: do people really have a choice in their behavior, and what governs them; is it free will or predetermination? Is it biology or environment is it the external world or the internal that drives addiction, or a complex combination of both?

In a contemporary context the media frenzy around celebrity addiction continually fuels public debate in this area, and this book deepens the understanding of addiction within this contentious context. This book addresses a key concern over how addiction became the norm, and it seeks to understand its dominance comprehensively. How did it come to pass that not being an addict was a transgressive act and way of being?

While there has been a great deal of debate about addiction utilizing the discourse of individual and often competing disciplines such as biology and psychology, little attention has been paid to the cultural aspects of addiction. The innovative approach taken by this book is to offer insights into this complex area through a contemporary methodology that covers diverse interrelated areas. Drawing on different disciplines, offering deeper insights, from the analysis of music lyrics to empirical social science and anthropological work in AA groups in Mexico and the portrayal of the “addiction’ to therapy in film and television, amongst other areas, this book addresses the need for a more comprehensive approach.

Academic analysis is also given to the discourse on celebrity culture and addiction. A contemporary fusion of the humanities and the social sciences is the best way forward to tackle this subject and move the debate on. The focus of this study is an innovative interdisciplinary and intercultural approach to addiction, from the social sciences to the humanities, including cultural studies, film and media studies, and literary studies. Areas that have been overlooked, such as lost women’s writings, are examined, in addition to comics, popular film and television, and the work of AA groups.

This edited collection is the first study to provide such a comprehensive analysis of the cultures of addiction. Traversing cultures across the globe, including Asia, Central America, as well as Europe and America, this book opens up the debate in addiction studies and cultural studies. The important insights the book delivers helps to answer questions such as: In what way can Deleuze further the understanding of addiction through the analysis of rock lyrics? How does anthropology improve the understanding of AA groups? How can cultural studies deepen knowledge on the “addiction” to therapy? These are just some of the vast array of areas this book covers. Other areas include the condemnation of “addiction” to comic reading through an historical examination, violence in popular culture, and lost women’s writing on addiction. No other book has such depth and contemporary breadth.

Cultures of Addiction is an important book for those taking cultural studies courses across a range of interrelated disciplines, including English and literary studies, history, American studies, and film and media studies. This will be invaluable to library collections in these fields and beyond in the social sciences, and specifically in addiction studies and psychology.

(Jason Lee, Editor)

Azide photochemistry for facile modification of graphitic surfaces : preparation of DNA-coated carbon nanotubes for biosensing

A facile, two-step method for chemically attaching single-stranded DNA to graphitic surfaces, represented here by carbon nanotubes, is reported. In the first step, an azide-containing compound, N-5-azido-nitrobenzoyloxy succinimide (ANB-NOS), is used to form photo-adducts on the graphitic surfaces in a solid-state photochemical reaction, resulting in active ester groups being oriented for the subsequent reactions. In the second step, pre-synthesized DNA strands bearing a terminal amine group are coupled in an aqueous solution with the active esters on the photo-adducts. The versatility of the method is demonstrated by attaching pre-synthesized DNA to surfaces of carbon nanotubes in two platforms—as vertically-aligned multi-walled carbon nanotubes on a solid support and as tangled single-walled carbon nanotubes in mats. The reaction products at various stages were characterized by x-ray photoelectron spectroscopy. Two different assays were used to check that the DNA strands attached to the carbon nanotubes were able to bind their partner strands with complementary base sequences. The first assay, using partner DNA strands tethered to gold nanoparticles, enabled the sites of DNA attachment to the carbon nanotubes to be identified in TEM images. The second assay, using radioactively labelled partner DNA strands, quantified the density of functional DNA strands attached to the carbon nanotubes. The diversity of potential applications for these DNA-modified carbon-nanotube platforms is exemplified here by the successful use of a DNA-modified single-walled carbon-nanotube mat as an electrode for the specific detection of metal ions.

Influence of hydrogen peroxide in the preparation of nanocrystalline ceria

The influence of H2O2 in the preparation of nanocrystalline CeO2 has been investigated by treating solutions of Ce(III) with NaOH in the presence of different concentrations of H2O2. The resulting precipitated material was then examined by a range of techniques, including transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). A decrease in CeO2 crystallite size with increasing H2O2 concentration was observed. This was found to be associated with the formation of an amorphous material containing an η2-peroxide (O22-) species.

Preparation of silica abrasives from water glass and application in silicon wafer polishing

Chemical mechanical polishing technique is more frequently adopted for planarization in integrated circuit fabrication. The silica abrasives in colloidal state are fabricated with the sodium silicate solution as raw materials through the polymerization reaction among silicic acid molecules. By continuous injection of silicic acid into the preexisting silica solution, the diameter of silica nanoparticles increases. The different sized silica nanoparticles are imaged by scanning electron microscopy, and the dried silica are characterized by X-ray diffraction and thermal analysis. The polishing test on silicon wafer with as-fabricated silica abrasives shows that the surface flatness reaches 1.1 nm roughness, however, micro scratches are still present in the surface.