Synthesis and characterisation of nanoscale magnesium oxide powders and their application in thick films of Bi2Sr2CaCu2O8

Nanoscale MgO powder was synthesized from magnesite ore by a wet chemical method. Acid dissolution was used to obtain a solution from which magnesium containing complexes were precipitated by either oxalic acid or ammonium hydroxide, The transformation of precipitates to the oxide was monitored by thermal analysis and XRD and the transformed powders were studied by electron microscopy. The MgO powders were added as dopants to Bi2SrCa2CuO8 powders and high temperature superconductor thick films were deposited on silver. Addition of suitable MgO powder resulted in increase of critical current density, J(c), from 8,900 Acm(-2) to 13,900 Acm(-2) measured at 77 K and 0 T. The effect of MgO addition was evaluated by XRD, electron microscopy and critical current density measurements. (C) 1998 Elsevier Science B.V.

Synthesis and characterisation of organo-beidellite

Today, there are growing concerns about the presence of environmental pollutants in many parts of the world. In particular, a lot of attention has been drawn to the levels of water and soil contaminants (de Paiva et al., 2008). The majority of these contaminants consist of NOCs (non-ionic organic compounds) and can enter our waterways through industrial activities, mining operations, crop and animal production, waste disposal and accidental leakage (de Paiva et al., 2008; Park et al., 2011). Therefore, there is an increased interest in the synthesis of new materials that can be used to remove potentially carcinogenic and toxic water contaminants. Smectite type organoclays are widely used in numerous applications, such as sorbent agents for environmental remediation, due to their unique properties (Jiunn-Fwu et al., 1990; Sheng et al., 1996; Zhou et al., 2007; Bektas et al., 2011; Park et al., 2011). This investigation focuses on beidellite (SBId-1), which belongs to the smectite clay family. Their properties include high cation exchange capacity (CEC), swelling properties, porous, high surface area and consequential strong adsorption/absorption capacity (Xi et al., 2007). However, swelling clays in general are not an effective sorbent agent in nature due to their hydrophilic properties. The hydrophilic properties of the clay can be changed to organophilic by intercalating a cationic surfactant. Many applications of organoclays are strongly dependent on their structural properties and hence, a better understanding of the configuration and structural change of organoclay is crucial. Organoclays were synthesised through ion exchange of 21CODTMA (MW: 392.5 g mol-1) and characterised using XRD and FTIR spectroscopy. This study investigates the structural and conformational changes of beidellite intercalated with octadecyltrimethylammonium bromide.

Bike share : a synthesis of the literature

This paper begins by providing an overview of bike share programs, followed by a critical examination of the growing body of literature on these programs. This synthesis of previous works, both peer-reviewed and grey, includes an identification of the current gaps in knowledge related to the impacts of bike sharing programs. This synthesis represents a critically needed evaluation of the current state of global bike share research, in order to better understand, and maximize the effectiveness of current and future programs. Several consistent themes have emerged within the growing body of research on bike share programs. Firstly, the importance bike share members place on convenience and value for money appears paramount in their motivation to sign up and use these programs. Secondly, and somewhat counter intuitively, scheme members are more likely to own and use private bicycles than non-members. Thirdly, users demonstrate a greater reluctance to wear helmets than private bicycle riders and helmets have acted as a deterrent in jurisdictions in which helmets are mandatory. Finally, and perhaps most importantly from a sustainable transport perspective, the majority of scheme users are substituting from sustainable modes of transport rather than the car.

Peer assisted learning, skills development and Generation Y : a case study of a first year undergraduate law unit

The majority of current first year university students belong to Generation Y. Consequently, research suggests that, in order to more effectively engage them, their particular learning preferences should be acknowledged in the organisation of their learning environments and in the support provided. These preferences are reflected in the Torts Student Peer Mentor Program, which, as part of the undergraduate law degree at the Queensland University of Technology, utilises active learning, structured sessions and teamwork to supplement student understanding of the substantive law of Torts with the development of life-long skills. This article outlines the Program, and its relevance to the learning styles and experiences of Generation Y first year law students transitioning to university, in order to investigate student perceptions of its effectiveness – both generally and, more specifically, in terms of the Program’s capacity to assist students to develop academic and work-related skills.

Skill development and social inclusion via peer assisted learning in first-year higher education : an evaluation of student experiences across two law units

Because professions seek graduates who can 'collaborate, share skills and knowledge, and communicate' (Kruck and Reif, 2001, p 37), it is important that university graduates are not equipped solely with the content knowledge of their discipline, but also with prospective employment skills. Furthermore, when students 'interact more in positive ways with their teachers and peers, they gain more in terms of essential skills and competencies, such as critical thinking, problem~solving [and] effective communication' (NSSE, 2000, p 2)./n this way, peer assisted fellowing has the potential to enhance students' professional development, and provide the social inclusion and engagement necessary for effective learning. This session describes two peer assisted learning models embedded within first year QUT Faculty of Law units. Through a partnership between teaching staff, student mentors and mentees, the models aim to facilitate student socialisation whilst supplementing understanding of substantive law with the development of academic and work·related skills. Mentor and mentee perceptions, and program implications, are considered.

Consumer acceptance of an SMS-assisted smoking cessation intervention : a multicountry study

This study assesses smokers' perceptions, motivations, and intentions towards using an SMS-assisted smoking cessation intervention in Australia, France, and Mexico through an extended technology acceptance model with mediating variables. Data was collected through online surveys. Results show that perceived usefulness and vicarious innovativeness predict use intentions for all three countries. Perceived ease of use is significant only for Mexico. Subjective norms are significant only for Mexico and Australia. Perceived monetary value and perceived annoyance are significant mediating variables for all three countries, whereas perceived enjoyment is significant only for Mexico and Australia. These results contribute to theory and practice.

Magnetic zeolite NaA : Synthesis, characterization based on metakaolin and its application for the removal of Cu2+, Pb2+

The optimum parameters for synthesis of zeolite NaA based on metakaolin were investigated according to results of cation exchange capacity and static water adsorption of all synthesis products and selected X-ray diffraction (XRD). Magnetic zeolite NaA was synthesized by adding Fe3O4 in the precursor of zeolite. Zeolite NaA and magnetic zeolite NaA were characterized with scanning electron microscopy (SEM) and XRD. Magnetic zeolite NaA with different Fe3O4 loadings was prepared and used for removal of heavy metals (Cu2+, Pb2+). The results show the optimum parameters for synthesis zeolite NaA are SiO2/Al2O3 = 2.3, Na2O/SiO2 = 1.4, H2O/Na2O = 50, crystallization time 8 h, crystallization temperature 95 �C. The addition of Fe3O4 makes the NaA zeolite with good magnetic susceptibility and good magnetic stability regardless of the Fe3O4 loading, confirming the considerable separation efficiency. Additionally, Fe3O4 loading had a little effect on removal of heavy metal by magnetic zeolite, however, the adsorption capacity still reaches 2.3 mmol g�1 for Cu2+, Pb2+ with a removal efficiency of over 95% in spite of 4.7% Fe3O4 loading. This indicates magnetic zeolite can be used to remove metal heavy at least Cu2+, Pb2+ from water with metallic contaminants and can be separated easily after a magnetic process.

Approaches to the Synthesis of a Water-soluble Carboxy Nitroxide

The robust and diversely useful isoindoline nitroxide, 5-carboxy-1,1,3,3-tetramethylisoindolin-2-yloxyl (1; CTMIO), has previously been synthesised in low-to-moderate yields from phthalic anhydride (3). Recent interest in its biological potential as a potent antioxidant and in other areas has seen an increased demand for its production. Herein, three new synthetic routes to CTMIO are presented and their efficiencies assessed. Two routes, via the nitrile 9 and the formyl compound 11, derive from 5-bromo-1,1,3,3-tetramethylisoindoline (6). The third approach starts from the readily accessible starting material, 4-methylphthalic anhydride (12), and proceeds by a methylarene oxidation with potassium permanganate. The three new approaches yield CTMIO in comparable overall yields (16–18 %); however, the synthetic efficiency is most improved when employing the nitrile intermediate 9.

The right to choose an assisted death : time for legislation?

The legal framework that operates at the end of life in Australia needs to be reformed. • Voluntary euthanasia and assisted suicide are currently unlawful. • Both activities nevertheless occur not infrequently in Australia, in part because palliative care cannot relieve physical and psychological pain and suffering in all cases. • In this respect, the law is deficient. The law is also unfair because it doesn’t treat people equally. Some people can be helped to die on their own terms as a result of their knowledge and/or connections while some are able to hasten their death by the refusal of life-sustaining treatment. But others do not have access to the means for their life to end. • A very substantial majority of Australians have repeatedly expressed in public opinion polls their desire for law reform on these matters. Many are concerned at what they see is happening to their loved ones as they reach the end of their lives, and want the confidence that when their time comes they will be able to exercise choice in relation to assisted dying. • The most consistent reason advanced not to change the law is the need to protect the vulnerable. There is a concern that if the law allows voluntary euthanasia and assisted suicide for some people, it will be expanded and abused, including pressures being placed on highly dependent people and those with disabilities to agree to euthanasia. • But there is now a large body of experience in a number of international jurisdictions following the legalisation of voluntary euthanasia and/or assisted suicide. This shows that appropriate safeguards can be implemented to protect vulnerable people and prevent the abuse that opponents of assisted dying have feared. It reveals that assisted dying meets a real need among a small minority of people at the end of their lives. It also provides reassurance to people with terminal and incurable disease that they will not be left to suffer the indignities and discomfort of a nasty death. • Australia is an increasingly secular society. Strong opposition to assisted death by religious groups that is based on their belief in divine sanctity of all human life is not a justification for denying choice for those who do not share that belief. • It is now time for Australian legislators to respond to this concern and this experience by legislating to enhance the quality of death for those Australians who seek assisted dying.

Synthesis of an erodible biomimetic hydrogel for drug delivery using native chemical ligation

Hydrogels are hydrophilic, three dimensional polymers that imbibe large quantities of water while remaining insoluble in aqueous solutions due to chemical or physical cross-linking. The polymers swell in water or biological fluids, immobilizing the bioactive agent, leading to drug release in a well-defined specific manner. Thus the hydrogels’ elastic properties, swellability and biocompatibility make them excellent formulations for drug delivery. Currently, many drug potencies and therapeutic effects are limited or otherwise reduced because of the partial degradation that occurs before the administered drug reaches the desired site of action. On the other hand, sustained release medications release drugs continually, rather than providing relief of symptoms and protection solely when necessary. In fact, it would be much better if drugs could be administered in a manner that precisely matches physiological needs at desired times and at the desired site (site specific targeting). There is therefore an unmet need to develop controlled drug delivery systems especially for delivery of peptide and protein bound drugs. The purpose of this project is to produce hydrogels for structural drug delivery and time-dependent sustained release of drugs (bioactive agents). We use an innovative polymerisation strategy based on native chemical ligation (NCL) to covalently cross-link polymers to form hydrogels. When mixed in aqueous solution, four armed (polyethylene glycol) amine (PEG-4A) end functionalised with thioester and four branched Nterminal cysteine peptide dendrimers spontaneously conjugated to produce biomimetic hydrogels. These hydrogels showed superior resistance to shear stress compared to an equivalent PEG macromonomer system and were shown to be proteolytically degradable with concomitant release of a model payload molecule. This is the first report of a peptide dendrimers/PEG macromonomer approach to hydrogel production and opens up the prospect of facile hydrogel synthesis together with tailored payload release.

Synthesis, structural analysis, and thermal decomposition studies of [(NH3)2BH2]B3H8

Boron–nitrogen containing compounds with high hydrogen contents as represented by ammonia borane (NH3BH3) have recently attracted intense interest for potential hydrogen storage applications. One such compound is [(NH3)2BH2]B3H8 with a capacity of 18.2 wt% H. Two safe and efficient synthetic routes to [(NH3)2BH2]B3H8 have been developed for the first time since it was discovered 50 years ago. The new synthetic routes avoid a dangerous starting chemical, tetraborane (B4H10), and afford a high yield. Single crystal X-ray diffraction analysis reveals N–Hδ+Hδ−–B dihydrogen interactions in the [(NH3)2BH2]B3H8·18-crown-6 adduct. Extended strong dihydrogen bonds were observed in pure [(NH3)2BH2]B3H8 through crystal structure solution based upon powder X-ray analysis. Pyrolysis of [(NH3)2BH2]B3H8 leads to the formation of hydrogen gas together with appreciable amounts of volatile boranes below 160 °C.

Microbial colonisation of follicular fluid : alterations in cytokine expression and adverse assisted reproductive technology outcomes

Previous studies have measured cytokine expression within follicular fluid collected at the time of trans-vaginal oocyte retrieval and compared the profiles with the aetiology of infertility and/or successful or unsuccessful assisted reproductive technology (ART) outcomes. Seventy-one paired follicular fluid and vaginal swab specimens collected from ART patients were cultured to detect microorganisms and then were tested for the presence of cytokines by multiplex fluorescence bead assays. Specimen selection was based on two criteria: whether the follicular fluid specimen was colonised (with microorganisms prior to oocyte retrieval) or contaminated by lower genital tract microflora at the time of oocyte retrieval and; the aetiology of infertility...

Microwave synthesis and spectroscopic characterization of manganese oxalate nanocrystals

The microwave synthesis of MnC2O4·2H2O nanoparticles was performed through the thermal double decomposition of oxalic acid dihydrate (C2H2O4·2H2O) and Mn(OAc)2·4H2O solutions using a CATA-2R microwave reactor. Structural characterization was performed using X-ray diffraction (XRD), particle size and shape were analyzed using transmission electron microscopy (TEM). The chemical in the structures was investigated using electron paramagnetic resonance (EPR) as well as optical absorption spectra and near-infrared (NIR) spectroscopies. The nanocrystals produced with this method were pure and had a distorted rhombic octahedral structure.

Factors associated with suboptimal adherence to antiretroviral therapy in Viet Nam: A cross-sectional study using audio computer-assisted self-interview (ACASI)

Background: Optimal adherence to antiretroviral therapy (ART) is necessary for people living with HIV/AIDS (PLHIV). There have been relatively few systematic analyses of factors that promote or inhibit adherence to antiretroviral therapy among PLHIV in Asia. This study assessed ART adherence and examined factors associated with suboptimal adherence in northern Viet Nam. Methods: Data from 615 PLHIV on ART in two urban and three rural outpatient clinics were collected by medical record extraction and from patient interviews using audio computer-assisted self-interview (ACASI). Results: The prevalence of suboptimal adherence was estimated to be 24.9% via a visual analogue scale (VAS) of past-month dose-missing and 29.1% using a modified Adult AIDS Clinical Trial Group scale for on-time dose-taking in the past 4 days. Factors significantly associated with the more conservative VAS score were: depression (p < 0.001), side-effect experiences (p < 0.001), heavy alcohol use (p = 0.001), chance health locus of control (p = 0.003), low perceived quality of information from care providers (p = 0.04) and low social connectedness (p = 0.03). Illicit drug use alone was not significantly associated with suboptimal adherence, but interacted with heavy alcohol use to reduce adherence (p < 0.001). Conclusions: This is the largest survey of ART adherence yet reported from Asia and the first in a developing country to use the ACASI method in this context. The evidence strongly indicates that ART services in Viet Nam should include screening and treatment for depression, linkage with alcohol and/or drug dependence treatment, and counselling to address the belief that chance or luck determines health outcomes.

Synthesis of discrete allyl-functional polyethylene glycol for efficient hydrophilization of dihydr (polydimethylsiloxane)

Amphiphilic poly(ethylene glycol)-block-pol (dimethylsiloxane)-block-poly(ethylene glycol)(PEG-block-PDMS block-PEG) triblock copolymers have been successfully prepared via hydrosilylation using discrete and polydisperse PEG of various chain lengths. Facile synthesis of discrete PEG (dPEG) is achieved via systematic tosylation and etherification of lower glycols. Amphiphilicity of the dPEG block-PDMS-block-dPEG triblock copolymer is illustrated by dynamic light scattering (DLS) and measurement of the critical micelle concentration (CMC).