A study on the reaction of silicon tetrahalides with phosphorus pentoxide and of alkali metal fluorosilicates with phosphorus pentoxide and sulphur trioxide

Silicon tetrahalides, SiX4 (X=F, Cl, Br) and the fluorosilicates of sodium and potassium react with phosphorus pentoxide above 300°C. The tetrahalides give rise to the corresponding phosphoryl halides and silica, while the fluorosilicates form the corresponding metal fluorophosphates and silicon tetrafluoride. The reaction of the fluorosilicates of sodium and potassium with sulphur trioxide occurs at room temperature to give rise to the corresponding metal fluorosulphates and silicon tetrafluoride.

Topochemically controlled hydrogen reduction of scheelite-related rare-earth metal molybdates

Scheelite-related -Ln2Mo3O12(Ln = La, Pr, Nd, Sm, Gd, Tb, or Dy) oxides are reduced by hydrogen at 780–870 K yielding molybdenum (IV) oxides of formula Ln2Mo3O9. The latter crystallize in a tetragonal scheelite (ABO4) type structure where one third of the A sites and a quarter of the anion sites are vacant: Ln2/3(cat)1/3MoO3(an). The reaction Ln2Mo3O12+ 3H2 Ln2Mo3O9(an)3+ 3H2O may be regarded as topochemically controlled, since both the parent and the product phases have scheelite-related structures. Infrared spectra and electrical and magnetic properties of these metastable defect scheelite phases are reported.

Thermal decomposition of alkali metal perchlorates

The effect of past mechanical history on the subsequent thermal decomposition kinetics of sodium, potassium, rubidium and caesium perchlorates, has been investigated. At low temperatures the decomposition of all these salts is significantly sensitized by pre-compression. At high temperatures, however, prior compression results in a lowered decomposition rate in the case of potassium, rubidium and caesium perchlorates and in an increase in the thermal reactivity of sodium perchlorate. The high temperature behaviour is shown to be an indirect consequence of the low temperature behaviour. The difference in behaviour between sodium perchlorate and the other alkali metal perchlorates is explained on the basis of the stability of the respective chlorates, formed during the low temperature decomposition. This is substantiated by experiments which show that the addition of sodium chlorate to sodium perchlorate brings about a sensitization while potassium perchlorate admixed with potassium chlorate results in a desensitization at high temperatures.

Information Visualization in a Business Decision Support System

Information visualization is a process of constructing a visual presentation of abstract quantitative data. The characteristics of visual perception enable humans to recognize patterns, trends and anomalies inherent in the data with little effort in a visual display. Such properties of the data are likely to be missed in a purely text-based presentation. Visualizations are therefore widely used in contemporary business decision support systems. Visual user interfaces called dashboards are tools for reporting the status of a company and its business environment to facilitate business intelligence (BI) and performance management activities. In this study, we examine the research on the principles of human visual perception and information visualization as well as the application of visualization in a business decision support system. A review of current BI software products reveals that the visualizations included in them are often quite ineffective in communicating important information. Based on the principles of visual perception and information visualization, we summarize a set of design guidelines for creating effective visual reporting interfaces.

Three-component assembly of a metal-inorganic 3D Co(II) polymer containing bridging hydrazine

Three-component metal-inorganic assembly of a Co(II) network representing the first example of a 3D coordination polymer containing a hydrazine bridging ligand, has been synthesized and characterized.

Superhydrophobic fabrics for oil-water separation based on the metal organic charge transfer complex CuTCNAQ

This work reports on the fabrication of a superhydrophobic nylon textile based on the organic charge transfer complex CuTCNAQ (TCNAQ = 11,11,12,12-tetracyanoanthraquinodimethane). The nylon fabric that is metallized with copper undergoes a spontaneous chemical reaction with TCNAQ dissolved in acetonitrile to form nanorods of CuTCNAQ that are intertwined over the entire surface of the fabric. This creates the necessary micro and nanoscale roughness that is required for the Cassie-Baxter state thereby achieving a superhydrophobic/superoleophilic surface without the need for a fluorinated surface. The material is characterised with SEM, FT-IR and XPS spectroscopy and investigated for its ability to separate oil and water in two modes, namely under gravity and as an absorbent. It is found that the fabric can separate dichloromethane, olive oil and crude oil from water and in fact reduce the water content of the oil during the separation process. The fabric is reusable and tolerant to conditions such as seawater, hydrochloric acid and extensive time periods on the shelf. Given that CuTCNAQ is a copper based semiconductor may also open up the possibility of other applications in areas such as photocatalysis and antibacterial applications.

Incomplete decomposition of alkali metal azides

The thermal decomposition of sodium azide has been studied in the temperature range 240–360°C in vacuum and under pressure of an inert gas, argon. The results show that the decomposition is partial 360°C. From the observations made in the present work, namely: (i) the decomposition is incomplete both under vacuum and inert gas; (ii) mass spectrometric studies do not reveal any decrease in the intensity of the background species, CO+2, CO+, H2O+, and (iii) sodium metal remains in the ‘free state’ as seen by the formation of a metallic mirror at temperatures above 300°C, it has been argued that the partial nature of decompostion is due to the confinement of the decomposition to intermosaic regions within the lattice.

Crystal structure and semiconductor-metal transition of the quasi-two-dimensional transition metal oxide, La2NiO4

Abstract is not available.

Can a single resource support many consumer species

The conclusion that the number of species co-existing within a biological community cannot exceed the number of limiting factors is not valid if we assume that (i) the relative efficiency of two competing species in utilizing a resource is not independent of the resource density, but one species may be more efficient at a lower density and less efficient at a higher density and (ii) there is a spatial or temporal heterogeneity in the density of the resource. This spatial or temporal heterogeneity does not have to be furnished by factors external to the biological community, but may be generated within the biological community itself as in the case of a vertical gradient of light in a plant community. This possibility of a stable co-existence of more than one species in a community limited by a single resource, even when the resource is being supplied uniformly in space and time, is formally demonstrated.

Electron Spectroscopic Studies of Oxygen and Carbon Dioxide Adsorbed on Metal Surfaces

Adsorption of oxygen on Ni, Cu, Pd, Ag, and Au surfaces has been investigated by employing UV and X-ray photoelectron spectrscopy as well as electron energy loss spectroscopy (EELS). Molecularly chemisorbed (singlet) oxygen is found on Ni, Cu, Ag, and Au surfaces showing features such as stabilization of the rB* orbital, destabilization of the .nu orbital, higher O(1s) binding energy than the atomic species, and a band 2-3 eV below the Fermi level due to metal d-O(2p)u* interaction. 0-0 and metal-oxygen stretching frequencies have been observed in EELS. Physical adsorption of O2 is found to occur on Pd and Ni surfaces, only at high exposures in the latter case. Physical adsorption and multilayer condensation of CO, on metal surfaces are distinguished by characteristic relaxation shifts in UPS as well as O(1s) binding energies. Adsorption of CO on a Ni surface covered with presorbed atomic oxygen gives rise to C02.

Spirituality in Indian University students and its associations with socioeconomic status, religious background, social support, and mental health

The present study aimed to understand spirituality and its relationships with socioeconomic status (SES), religious background, social support, and mental health among Indian university students. It was hypothesized that: - (1) female university students will be more spiritual than male university students, - (2) four domains of spirituality will differ significantly across socioeconomic and religious background of the university students in addition to social support, and; - (3) there will be a positive relationship between spirituality and mental health of university students, irrespective of gender. A group of 475 postgraduate students aged 20–27 years, 241 males and 234 females, from various disciplines of Pondicherry University, India, participated in the study. Students’ background was collected using a structured questionnaire. Overall spirituality and its four dimensions were measured using the Spirituality Attitude Inventory, while mental health status was estimated based on scores of the psychological subscale of the WHO Quality of Life Questionnaire. Female students were significantly more spiritual than male students, particularly in spiritual practice and sense of purpose/connection. Hindu religion and lower family income were associated with lower spirituality. Higher spirituality was associated with congenial family environment and more support from teachers and classmates. There was a strong association between overall spirituality and two spirituality domains (spiritual belief and sense of purpose/connection) with better mental health. Findings suggest an opportunity for open dialogue on spirituality for university students as part of their mental health and support services that fosters a positive mind set and enhancement of resilience.

The professional development, resource and support needs of rural and urban ICT teachers

This paper presents findings from the SiMERR National Survey concerning the need priorities of secondary ICT teachers for professional development, resources and student learning experiences. The findings - drawn from a survey of 237 secondary ICT teachers across Australia - provide an opportunity to compare the needs of teachers working in metropolitan, provincial and remote schools. The study found that vacant ICT positions are difficult to fill ond that the novel on dynamic nature of ICT requires teachers to have more extensive opportunities for on-the-job training, collegial collaboration and mentoring than is the case for teachers of more traditional subjects like science and mathematics. The study also found that ICT teachers are commonly required to manage and maintain ICT resources and to assist other staff to use ICT resources, while being allocated insufficient time in which to do these additional activities. The implications of these and other findings are discussed along with recommendations to help address the needs of ICT teachers in different parts of Australia.

An online community designed to support future makers in educational reform

Australian education is undergoing national reform at many levels. The school sector, where preservice teachers will be employed, are adjusting to the demands of the National Curriculum and improving teacher quality through the National Professional Standards for Teachers. In addition, the university sector, where pre-service teachers are prepared, is undergoing its own education reform through the introduction of a demand-driven system and ensuring quality for tertiary education interns through the Higher Education Standards Framework. In moving to prepare preservice teachers for the school system; universities are grappling with the double-barreled approach to teacher quality; quality within the university course and quality within the student teachers being prepared. Through a collaborative partnership including university lecturers, Department of Education central administration staff, school principals, school coordinators, practicum supervisors, mentor teachers and pre-service teachers; the stakeholders have formed an online community of learners engaging in reflective practice who are committed to improving teacher quality. This online community not only links the key stakeholders within the project, it facilitates the nexus between theory and practice often missing in our pre-service teacher placements. This paper reports preliminary data about an initiative to ensure final year pre-service teachers are aspiring to meet the graduate professional standards through the use of an innovative online community.

Metal-insulator transition of naxwo3 studied by angle-resolved photoemission spectroscopy

The electronic structure of sodium tungsten bronzes NaxWO3 is investigated by high-resolution angle-resolved photoemission spectroscopy (ARPES). The ARPES spectra measured in both insulating and metallic phases of NaxWO3 reveals the origin of metal-insulator transition (MIT) in sodium tungsten bronze system. It is found that in insulating NaxWO3 the states near the Fermi level (E-F) are localized due to the strong disorder caused by the random distribution of Na+ ions in WO3 lattice. Due to the presence of disorder and long-range Coulomb interaction of conduction electrons, a soft Coulomb gap arises, where the density of states vanishes exactly at E-F. In the metallic regime the states near E-F are populated and the Fermi level shifts upward rigidly with increasing electron doping (x). Volume of electron-like Fermi surface (FS) at the Gamma(X) point of the Brillouin zone gradually increases with increasing Na concentration due to W 5d t(2g) band filling. A rigid shift of the Fermi energy is found to give a qualitatively good description of the Fermi surface evolution. As we move from bulk-sensitive to more surface sensitive photon energy, we found the emergence of Fermi surfaces at X(M) and M(R) point similar to the one at the Gamma(X) point in the metallic regime, suggesting that the reconstruction of surface was due to rotation/deformation of WO6 octahedra.

Photocytotoxic 3d-Metal Scorpionates with a 1,8-Naphthalimide Chromophore Showing Photoinduced DNA and Protein Cleavage Activity

Ternary 3d-metal complexes of formulation [M(Tp(Ph))(py-nap)](ClO4)(1-3), where M is Co(II) (1), Cu(II) (2), and Zn(II) (3); Tp(Ph) is anionic tris (3-phenylpyrazolyl)borate; and py-nap is a pyridyl ligand with a conjugated 1,8-naphthalimide moiety, have been prepared from the reaction of metal perchlorate with KTp(Ph) and py-nap in CH2Cl2. The complexes have been characterized from analytical and physicochemical data. The complexes are stable in solution as evidenced from the electrospray ionization mass spectrometry data. The complexes show good binding propensity with calf thymus (CT) DNA, giving binding constant (K-b) values of similar to 10(5) M-1 and a molecular ``light-switch'' effect that results in an enhancement of the emission intensity of the naphthalimide chromophore on binding to CT DNA. The complexes do not show any hydrolytic cleavage of DNA. They show poor chemical nuclease activity in the presence of 3-mercaptopropionic acid or hydrogen peroxide (H2O2). The Co(II) and Cu(II) complexes exhibit oxidative pUC19 DNA cleavage activity in UV-A light of 365 rim. The Zn(II) complex shows moderate DNA photocleavage activity at 365 nm. The Cu(II)complex 2 displays photoinduced DNA cleavage activity in red light of 647.1 nm and 676 rim and near-IR light of >750 rim. A mechanistic studyin UV-A and visible light suggests the involvement of the hydroxyl radical as the reactive species in the DNA photocleavage reactions. The complexes also show good bovine serum albumin (BSA) protein binding propensity, giving K-BSA values of similar to 10(5) M-1. Complexes 1 and 2 display significant photoinduced BSA cleavage activity in UV-A light. The Co(II) complex 1 shows a significant photocytotoxic effect in HeLa cervical cancer cells on exposure to UV-A light of 365 nm, giving an IC50 value of 32 mu M. The IC50 value for the py-nap ligand alone is 41.42 mu m in UV-A light. The IC50 value is >200 mu M in the dark, indicating poor dark toxicity of 1. The Cu(II) complex 2 exhibits moderate photocytotoxicity and significant dark toxicity, giving IC50 values of 18.6 mu m and 29.7 mu m in UV-A light and in the dark, respectively.