Vibrational spectroscopy of the borate mineral henmilite Ca2Cu[B(OH)4]2(OH)4

Henmilite is a triclinic mineral with the crystal structure consisting of isolated B(OH)4 tetrahedra, planar Cu(OH)4 groups and Ca(OH)3 polyhedra. The structure can also be viewed as having dimers of Ca polyhedra connected to each other through 2B(OH) tetrahedra to form chains parallel to the C axis. The structure of the mineral has been assessed by the combination of Raman and infrared spectra. Raman bands at 902, 922, 951, and 984 cm−1 and infrared bands at 912, 955 and 998 cm−1 are assigned to stretching vibrations of tetragonal boron. The Raman band at 758 cm−1 is assigned to the symmetric stretching mode of tetrahedral boron. The series of bands in the 400–600 cm−1 region are due to the out-of-plane bending modes of tetrahedral boron. Two very sharp Raman bands are observed at 3559 and 3609 cm−1. Two infrared bands are found at 3558 and 3607 cm−1. These bands are assigned to the OH stretching vibrations of the OH units in henmilite. A series of Raman bands are observed at 3195, 3269, 3328, 3396, 3424 and 3501 cm−1 are assigned to water stretching modes. Infrared spectroscopy also identified water and OH units in the henmilite structure. It is proposed that water is involved in the structure of henmilite. Hydrogen bond distances based upon the OH stretching vibrations using a Libowitzky equation were calculated. The number and variation of water hydrogen bond distances are important for the stability off the mineral.

Hepatitis B knowledge, testing, and vaccination among Chinese and Vietnamese adults in Australia

Hepatitis B is a significant public health challenge within some subpopulations in Australia, including Chinese and Vietnamese migrants. There has been limited research on hepatitis B knowledge and actions in these communities. The authors conducted a self-administered survey among 442 Chinese and 433 Vietnamese in Brisbane. Generally, the knowledge is best described as “moderate.” One in 2 could not identify the sexual transmission risk and less than one third knew that sharing foods or drinks did not spread the disease. The majority of Vietnamese (80%) and 60% of Chinese respondents indicated prior testing. Vaccination was reported in 60% of the Vietnamese and in 52% of the Chinese. Knowledge was better among Chinese people who had been tested and vaccinated compared with those who were nontested and nonvaccinated. Only 3.5% of the Chinese, but 11.6% of the Vietnamese, indicated having a positive test result hepatitis B virus. This study helps identify strategies for programs targeting both communities and practitioners.

Offsetting methane emissions : an alternative to emission equivalence metrics

It is widely recognised that defining trade-offs between greenhouse gas emissions using ‘emission equivalence’ based on global warming potentials (GWPs) referenced to carbon dioxide produces anomalous results when applied to methane. The short atmospheric lifetime of methane, compared to the timescales of CO2 uptake, leads to the greenhouse warming depending strongly on the temporal pattern of emission substitution. We argue that a more appropriate way to consider the relationship between the warming effects of methane and carbon dioxide is to define a ‘mixed metric’ that compares ongoing methane emissions (or reductions) to one-off emissions (or reductions) of carbon dioxide. Quantifying this approach, we propose that a one-off sequestration of 1 t of carbon would offset an ongoing methane emission in the range 0.90–1.05 kg CH4 per year. We present an example of how our approach would apply to rangeland cattle production, and consider the broader context of mitigation of climate change, noting the reverse trade-off would raise significant challenges in managing the risk of non-compliance. Our analysis is consistent with other approaches to addressing the criticisms of GWP-based emission equivalence, but provides a simpler and more robust approach while still achieving close equivalence of climate mitigation outcomes ranging over decadal to multi-century timescales.

Reply to William B. Grant

THE UVI working group acknowledges the contribution of Vitamin D to bone health as stated in our paper. However, we concluded that an optimal level of Vitamin D for humans has not yet been established with any certainty...

The feral horse foot. Part A : observational study of the effect of environment on the morphometrics of the feet of 100 Australian feral horses

Aim To better understand the morphology of, and the effect of different travel patterns and varying substrate environments on, the feral horse foot to better manage the feet of domestic horses. Methods The left forefeet of 20 adult feral horses from each of five geographically separated populations in Australia (n = 100) were investigated. Populations were selected on the basis of substrate hardness under foot and the amount of travel typical for the population. Feet were radiographed and photographed and 40 morphometric measurements of each foot were obtained. Results Of the 40 parameters, 37 differed significantly (P < 0.05) among the populations, which suggested that substrate hardness and travel distance have an effect on foot morphology. Harder substrates and longer travel distances were associated with short hoof walls and minimal hoof wall flaring. Softer substrates and moderate travel distances were associated with long flared walls, similar to that of typical untrimmed feet of domestic horses. Conclusions The morphology of the feral horse foot appeared to be affected by the distance travelled and by the abrasive qualities and mechanical properties of the substrate under foot. There were marked differences in some conformation parameters between the feral horses in the current study and domestic horses in previous studies. Although the conformation of the feral horse foot may have some prescriptive value, concerns regarding abnormal foot anatomy warrant further investigation.

Costly technology adoption, redistribution and growth

We study a political economy model which aims to understand the diversity in the growth and technology-adoption experiences in different economies. In this model the cost of technology adoption is endogenous and varies across heterogeneous agents. Agents in the model vote on the proportion of revenues allocated towards such expenditures. In the early stages of development, the political-economy outcome of the model ensures that a sub-optimal proportion of government revenue is used to finance adoption-cost reducing expenditures. This sub-optimality is due to the presence of inequality; agents at the lower end of the distribution favor a larger amount of revenue allocated towards redistribution in the form of lump-sum transfers. Eventually all individuals make the switch to the better technology and their incomes converge. The outcomes of the model therefore explain why public choice is more likely to be conservative in nature; it represents the majority choice given conflicting preferences among agents. Consequently, the transition path towards growth and technology adoption varies across countries depending on initial levels of inequality.

Investigation of energy efficient approaches for the energy performance improvement of commercial buildings

Energy efficiency of buildings is attracting significant attention from the research community as the world is moving towards sustainable buildings design. Energy efficient approaches are measures or ways to improve the energy performance and energy efficiency of buildings. This study surveyed various energy-efficient approaches for commercial building and identifies Envelope Thermal Transfer Value (ETTV) and Green applications (Living wall, Green facade and Green roof) as most important and effective methods. An in-depth investigation was carried out on these energy-efficient approaches. It has been found that no ETTV model has been developed for sub-tropical climate of Australia. Moreover, existing ETTV equations developed for other countries do not take roof heat gain into consideration. Furthermore, the relationship of ETTV and different Green applications have not been investigated extensively in any literature, and the energy performance of commercial buildings in the presence of Living wall, Green facade and Green roof has not been investigated in the sub-tropical climate of Australia. The study has been conducted in two phases. First, the study develops the new formulation, coefficient and bench mark value of ETTV in the presence of external shading devices. In the new formulation, roof heat gain has been included in the integrated heat gain model made of ETTV. In the 2nd stage, the study presents the relationship of thermal and energy performance of (a) Living wall and ETTV (b) Green facade and ETTV (c) Combination of Living wall, Green facade and ETTV (d) Combination of Living wall, Green Roof and ETTV in new formulations. Finally, the study demonstrates the amount of energy that can be saved annually from different combinations of Green applications, i.e., Living wall, Green facade; combination of Living wall and Green facade; combination of Living wall and Green roof. The estimations are supported by experimental values obtained from extensive experiments of Living walls and Green roofs.

Monte Carlo-based diode design for correction-less small field dosimetry

Due to their small collecting volume diodes are commonly used in small field dosimetry. However the relative sensitivity of a diode increases with decreasing small field size. Conversely, small air gaps have been shown to cause a significant decrease in the sensitivity of a detector as the field size is decreased. Therefore this study uses Monte Carlo simulations to look at introducing air upstream to diodes such that they measure with a constant sensitivity across all field sizes in small field dosimetry. Varying thicknesses of air were introduced onto the upstream end of two commercial diodes (PTW 60016 photon diode and PTW 60017 electron diode), as well as a theoretical unenclosed silicon chip using field sizes as small as 5 mm × 5 mm . The metric D_(w,Q)/D_(Det,Q) used in this study represents the ratio of the dose to a point of water to the dose to the diode active volume, for a particular field size and location. The optimal thickness of air required to provide a constant sensitivity across all small field sizes was found by plotting D_(w,Q)/D_(Det,Q) as a function of introduced air gap size for various field sizes, and finding the intersection point of these plots. That is, the point at which D_(w,Q)/D_(Det,Q) was constant for all field sizes was found. The optimal thickness of air was calculated to be 3.3 mm, 1.15 mm and 0.10 mm for the photon diode, electron diode and unenclosed silicon chip respectively. The variation in these results was due to the different design of each detector. When calculated with the new diode design incorporating the upstream air gap, k_(Q_clin 〖,Q〗_msr)^(f_clin 〖,f〗_msr ) was equal to unity to within statistical uncertainty (0.5 %) for all three diodes. Cross-axis profile measurements were also improved with the new detector design. The upstream air gap could be implanted on the commercial diodes via a cap consisting of the air cavity surrounded by water equivalent material. The results for the unclosed silicon chip show that an ideal small field dosimetry diode could be created by using a silicon chip with a small amount of air above it.

CO2 capture and gas separation on boron carbon nanotubes

Concern about the increasing atmospheric CO2 concentration and its impact on the environment has led to increasing attention directed toward finding advanced materials and technologies suited for efficient CO2 capture, storage and purification of clean-burning natural gas. In this letter, we have performed comprehensive theoretical investigation of CO2, N2, CH4 and H2 adsorption on B2CNTs. Our study shows that CO2 molecules can form strong interactions with B2CNTs with different charge states. However, N2, CH4 and H2 can only form very weak interactions with B2CNTs. Therefore, the study demonstrates B2CNTs could sever as promising materials for CO2 capture and gas separation.

Nuclear instruments and methods in physics research section B : beam interactions with materials and atoms

The impact-induced deposition of Al13 clusters with icosahedral structure on Ni(0 0 1) surface was studied by molecular dynamics (MD) simulation using Finnis–Sinclair potentials. The incident kinetic energy (Ein) ranged from 0.01 to 30 eV per atom. The structural and dynamical properties of Al clusters on Ni surfaces were found to be strongly dependent on the impact energy. At much lower energy, the Al cluster deposited on the surface as a bulk molecule. However, the original icosahedral structure was transformed to the fcc-like one due to the interaction and the structure mismatch between the Al cluster and Ni surface. With increasing the impinging energy, the cluster was deformed severely when it contacted the substrate, and then broken up due to dense collision cascade. The cluster atoms spread on the surface at last. When the impact energy was higher than 11 eV, the defects, such as Al substitutions and Ni ejections, were observed. The simulation indicated that there exists an optimum energy range, which is suitable for Al epitaxial growth in layer by layer. In addition, at higher impinging energy, the atomic exchange between Al and Ni atoms will be favourable to surface alloying.

In vitro models for investigating keratinocyte responses to ultraviolet B radiation

This thesis describes the use of 2- and 3-dimensional cell-based models for studying how skin cells respond to ultraviolet radiation. These methods were used to investigate skin damage and repair after exposure to radiation in the context of skin cancer development. Interactions between different skin cell types were demonstrated as being significant in protecting against ultraviolet radiation-induced skin damage. This has important implications in understanding how skin cancers occur, as well as in the development of new strategies to prevent and treat them.

Vibrational spectroscopy of the borate mineral olshanskyite Ca3[B(OH)4]4(OH)2

The mineral olshanskyite is one of many calcium borate minerals which has never been studied using vibrational spectroscopy. The mineral is unstable and decomposes upon exposure to an electron beam. This makes the elemental analysis using EDX techniques difficult. Both the Raman and infrared spectra show complexity due to the complexity of the structure. Intense Raman bands are found at 989, 1,003, 1,025 and 1,069 cm-1 with a shoulder at 961 cm-1 and are assigned to trigonal borate units. The Raman bands at 1,141, 1,206 and 1,365 cm-1 are assigned to OH in-plane bending of BOH units. A series of Raman bands are observed in the 2,900–3,621cm-1 spectral range and are assigned to the stretching vibrations of OH and water. This complexity is also reflected in the infrared spectra. Vibrational spectroscopy enables aspects of the structure of olshanskyite to be elucidated.

Pharmacokinetics of isofraxidin in rat plasma after oral administration of the extract of acanthopanax senticosus using HPLC with solid phase extraction method

High-performance liquid chromatography coupled with solid phase extraction method was developed for determination of isofraxidin in rat plasma after oral administration of Acanthopanax senticosus extract (ASE), and pharmacokinetic parameters of isofraxidin either in ASE or pure compound were measured. The HPLC analysis was performed on a Dikma Diamonsil RP(18) column (4.6 mm x 150 mm, 5 microm) with the isocratic elution of solvent A (acetonitrile) and solvent B (0.1% aqueous phosphoric acid, v/v) (A : B = 22 : 78) and the detection wavelength was set at 343 nm. The calibration curve was linear over the range of 0.156-15.625 microg/ml. The limit of detection was 60 ng/ml. The intra-day precision was 5.8%, and the inter-day precision was 6.0%. The recovery was 87.30+/-1.73%. When the dosage of ASE is equal to pure compound caculated by the amount of isofraxidin, it has been found to have two maximum concentrations in plasma while the pure compound only showed one peak in the plasma concentration-time curve. The determined content of isofraxidin in plasma after oral administration of ASE is the total contents of free isofraxidin and its precursors in ASE in vitro. The pharmacokinetic characteristics of ASE showed the priority of the extract and the properities of traditional Chinese medicine.

Pharmacokinetics of cimifugin in rat plasma after oral administration of the extract of Saposhnikovia divaricatae root : Determination of cimifugin by high performance liquid chromatography coupled with solid phase extraction

High performance liquid chromatography (HPLC) coupled with the solid phase extraction method was developed for determining cimifugin (a coumarin derivative; one of Saposhnikovia divaricatae's constituents) in rat plasma after oral administration of Saposhnikovia divaricatae extract (SDE), and the pharmacokinetics of cimifugin either in SDE or as a single compound was investigated. The HPLC analysis was performed on a commercially available column (4.6 mm x 200 mm, 5 pm) with the isocratic elution of solvent A (Methanol) and solvent B (Water) (A:B=60:40) and the detection wavelength was set at 250 nm. The calibration curve was linear over the range of 0.100-10.040 microg/mL. The limit of detection was 30 ng/mL. At the rat plasma concentrations of 0.402, 4.016, 10.040 microg/mL, the intra-day precision was 6.21%, 3.98%, and 2.23%; the inter-day precision was 7.59%, 4.26%, and 2.09%, respectively. The absolute recovery was 76.58%, 76.61%, and 77.67%, respectively. When the dosage of SDE was equal to the pure compound calculated by the amount of cimifugin, it was found to have two maximum peaks while the pure compound only showed one peak in the plasma concentration-time curve. The pharmacokinetic characteristics of SDE showed the superiority of the extract and the properties of traditional Chinese medicine.

A class B switch-mode assisted linear amplifier

A switch-mode assisted linear amplifier (SMALA) combining a linear (Class B) and a switch-mode (Class D) amplifier is presented. The usual single hysteretic controlled half-bridge current dumping stage is replaced by two parallel buck converter stages, in a parallel voltage controlled topology. These operate independently: one buck converter sources current to assist the upper Class B output device, and a complementary converter sinks current to assist the lower device. This topology lends itself to a novel control approach of a dead-band at low power levels where neither class D amplifier assists, allowing the class B amplifier to supply the load without interference, ensuring high fidelity. A 20 W implementation demonstrates 85% efficiency, with distortion below 0.08% measured across the full audio bandwidth at 15 W. The class D amplifier begins assisting at 2 W, and below this value, the distortion was below 0.03%. Complete circuitry is given, showing the simplicity of the additional class D amplifier and its corresponding control circuitry.