Onset of carbon-carbon bonding in the Nb5Cy (y = 0-6) clusters: a threshold photo-ionisation and density functional theory study

We have used photo-ionisation efficiency spectroscopy to determine the ionisation potentials (IPs) of the niobium–carbide clusters, Nb5Cy (y = 0–6). Of these clusters Nb5C2 and Nb5C3 exhibit the lowest IPs. Complementary density functional theory calculations have been performed to locate the lowest energy isomers for each cluster. By comparing the experimental IPs with those calculated for candidate isomers, the structures of the Nb5Cy clusters observed in the experiment are inferred. For all these structures, the underlying Nb5 cluster has either a ‘prolate’ or ‘oblate’ trigonal bipyramid geometry. Both Nb5C5 and Nb5C6 are shown to contain carbon–carbon bonding in the form of one and two molecular C2 units, respectively

Collisional electrochemistry of laser-ablated gold nanoparticles by electrocatalytic oxidation of glucose

We report the electrochemistry of gold nanoparticles (AuNPs), prepared by Laser Ablation Synthesis in Solution (LASiS), via the electrocatalytic oxidation of glucose upon single nanoparticle collisions at inert microelectrodes. Spherical AuNPs with diameters in the range 20–30 nm, as determined by transmission electron microscopy, were synthesized by LASiS of a gold plate immersed in water. Nanoparticle collisions were electrochemically detected through the AuNP-catalysed oxidation of glucose at carbon fiber microelectrodes in alkaline solution, enabling the electrocatalytic detection of single AuNPs. This approach provides a basis for detecting and understanding the electrocatalytic properties of pristine nanoparticles in aqueous solutions. © 2017 Elsevier B.V

APCELL: Developing better ways of teaching in the laboratory

The Australian Physical Chemistry Enhanced Laboratory Learning project was established to address deficiencies in Australian physical chemistry laboratory education. The project aims to pool the resources of over 30 universities to develop a protocol for developing and assuring the quality of laboratory teaching experiments. This protocol is based on ‘research-led teaching’ and is underpinned by education research literature. Because of its grounding in research, the project has demonstrated the potential to generate and support further research on teaching and student learning in laboratories. In this paper we describe the progress of the project to date and some of the research methodologies that have been employed

The Development of Teaching Skills to Support Active Learning in University Science (ALIUS)

This paper describes an Australian Learning and Teaching Council funded project for which Learning Design is encompassed in the broadest sense. ALIUS (Active Learning In University Science) takes the design of learning back to the learning experiences created for students. ALIUS is not about designing a particular activity, or subject, or course, but rather the development of a method, or process, by which we have re-designed the way in which learning occurs in large university classrooms world wide

ASELL : the advancing science by enhancing learning in the laboratory project

Most science educators and researchers will agree that the laboratory experience ranks as a major factor that influences students’ attitudes to their science courses. Consequently, good laboratory programs should play a major role in influencing student learning and performance. The laboratory program can be pivotal in defining a student\u27s experience in the sciences, and if done poorly, can be a major contributing factor in causing disengagement from the subject area. The challenge remains to provide students with laboratory activities that are relevant, engaging and offer effective learning opportunities

The ACELL project: Student participation, professional development, and improving laboratory learning

The Australian Physical Chemistry Enhanced Laboratory Learning (APCELL) project (Barrie, Buntine, Jamie and Kable 2001a, 2001b, 2001c), and its all-of-chemistry successor, ACELL (Read, 2006a) are examples of contemporary efforts to meet the challenge of engaging students in laboratory activities which are both chemically and educationally sound. The project is collaborative; it overcomes many of the significant constraints imposed by the unavailability of time from individual teachers, by drawing on the resources and expertise of multiple institutions as well as chemical and pedagogical expertise. The project continues to produce a range of tangible outcomes, including chemistry education research publications, a database of freely available tested experiments, and pedagogical design tools (all available from http://acell.chem.usyd.edu.au/). Objective evidence is required to support the putative notion that the A(P)CELL concept is of benefit to educators as they design and evaluate laboratory programs; collection and evaluation of such empirical data is essential if views such as those of Hawkes (2004) are to be effectively challenged. In this paper we report on the views of staff and student delegates to the February 2006 ACELL Educational Workshop

Photoionization efficiency spectroscopy and density functional theory investigations of RhHo2On, (n=0-2) clusters

The experimental and theoretical adiabatic ionization energies (IEs) of the rhodium-holmium bimetallic clusters RhHo(2)O(n) (n=0-2) have been determined using photoionization efficiency spectroscopy and density functional theory (DFT) calculations. Both sets of data show the IE of RhHo(2)O to be significantly lower than the values for RhHo(2) and RhHo(2)O(2), which are found to be similar. This indicates that there are significant changes in electronic properties upon sequential addition of oxygen atoms to RhHo(2). The DFT investigations show that the lowest energy neutral structures are a C(2v) triangle for RhHo(2), a C(2v) planar structure for RhHo(2)O where the O atom is doubly bridged to the Ho-Ho bond, and a C(2v) nonplanar structure for RhHo(2)O(2), where the O(2) is dissociative and each O atom is doubly bridged to the Ho-Ho bond in the cluster above and below the RhHo(2) trimer plane. Good correlation between the experimental and computational IE data imply that the lowest energy neutral structures calculated are the most likely isomers ionized in the molecular beam. In particular, the theoretical adiabatic IE for the dissociative RhHo(2)O(2) structure is found to compare better with the experimentally determined value than the corresponding lowest energy O(2) associative structure.Alexander S. Gentleman, Matthew A. Addicoat, Viktoras Dryza, Jason R. Gascooke, Mark A. Buntine, and Gregory F. Meth

The Australasian Resuscitation In Sepsis Evaluation : fluids or vasopressors in emergency department sepsis (ARISE FLUIDS), a multi-centre observational study describing current practice in Australia and New Zealand

Objectives: To describe haemodynamic resuscitation practices in ED patients with suspected sepsis and hypotension. Methods: This was a prospective, multicentre, observational study conducted in 70 hospitals in Australia and New Zealand between September 2018 and January 2019. Consecutive adults presenting to the ED during a 30-day period at each site, with suspected sepsis and hypotension (systolic blood pressure <100 mmHg) despite at least 1000 mL fluid resuscitation, were eligible. Data included baseline demographics, clinical and laboratory variables and intravenous fluid volume administered, vasopressor administration at baseline and 6- and 24-h post-enrolment, time to antimicrobial administration, intensive care admission, organ support and in-hospital mortality. Results: A total of 4477 patients were screened and 591 were included with a mean (standard deviation) age of 62 (19) years, Acute Physiology and Chronic Health Evaluation II score 15.2 (6.6) and a median (interquartile range) systolic blood pressure of 94 mmHg (87–100). Median time to first intravenous antimicrobials was 77 min (42–148). A vasopressor infusion was commenced within 24 h in 177 (30.2%) patients, with noradrenaline the most frequently used (n = 138, 78%). A median of 2000 mL (1500–3000) of intravenous fluids was administered prior to commencing vasopressors. The total volume of fluid administered from pre-enrolment to 24 h was 4200 mL (3000–5661), with a range from 1000 to 12 200 mL. Two hundred and eighteen patients (37.1%) were admitted to an intensive care unit. Overall in-hospital mortality was 6.2% (95% confidence interval 4.4–8.5%). Conclusion: Current resuscitation practice in patients with sepsis and hypotension varies widely and occupies the spectrum between a restricted volume/earlier vasopressor and liberal fluid/later vasopressor strategy

Recent Advances in Zinc-Containing Colloidal Semiconductor Nanocrystals for Optoelectronic and Energy Conversion Applications

Colloidal semiconductor nanocrystals (NCs), especially cadmium (Cd)- and lead (Pb)-containing ones, have been proved to be the promising materials for photoelectronic energy conversion applications. However, the high toxicity and cost of these materials restrict their widespread use. Zinc (Zn)-containing colloidal semiconductor NCs are non-/less toxic and environmentally friendly materials, manifesting in stimulating optical and electronic properties with relevance to a broad scope of applications including light-emitting diodes (LEDs), sensors, photocatalysts, and more. In this Review, we elaborate on the shape control of Zn-containing colloidal semiconductor NCs achieved by a variety of wet-chemical synthetic approaches. Moreover, the formation of core-shell, doped, and hybrid structures based on Zn-containing colloidal semiconductor NCs allow for the optimization of their functionalities, which underpin stimulating photoelectronic energy conversion applications in quantum-dot LEDs (QLEDs), photodetectors, and photocatalysis. Zn-containing colloidal semiconductor NCs that combine the green chemistry with sustainable developments possess a bright future

Excess energy-dependent photodissociation probabilities for O2- in water clusters: O2-.cntdot.(H2O)n, 1 .ltoreq. n .ltoreq. 33

David J. Lavrich, Mark A. Buntine, David Serxner, Mark A. Johnso