https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52053 Wed 27 Sep 2023 15:29:26 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:44998 −1, and injection volume was 10 μl. Detection was made at 254 nm by using a dual absorbance detector (DAD). The reversed-phase high-performance liquid chromatography (RP-HPLC) method has been developed and validated as per the current International Conference on Harmonization (ICH) guidelines to estimate hydroxychloroquine sulfate tablets. As part of method validation, specificity, linearity, precision, and recovery parameters were verified. The concentration and area relationships were linear (R² > 0.999) over the concentration range of 25–300 μg ml⁻¹ for hydroxychloroquine (HCQ). The relative standard deviations for precision and intermediate precision were <1.5%. The proposed RP-HPLC generic method was applied successfully to evaluate the in vitro dissolution profile with different pH conditions such as 0.1 N HCl, pH 4.5 acetate buffer, and pH 6.8 phosphate buffers as US-marketed reference products.]]> Wed 26 Oct 2022 09:23:16 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38705 Wed 13 Mar 2024 14:04:40 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:16483 Wed 11 Apr 2018 14:14:59 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:33010 SO₄ =(mSO₄/mCO₃)_solid/(mSO₄/mCO₃)_solution. High crystal growth rates (driven by either pH or saturation state) encouraged higher values of D_SO₄ because of an increasing concentration of defect sites on crystal surfaces. At low growth rates, D_SO₄ was reduced due to an inferred competition between sulphate and bicarbonate at the calcite surface. These experimental results are applied to understand the incorporation of sulphate into speleothem calcite. The experimentally determined pH-dependence suggests that strong seasonal variations in cave air PCO₂ could account for annual cycles in sulphate concentration observed in stalagmites. Our new experimentally determined values of D_SO₄ were compared with D_SO₄ values calculated from speleothem-drip water monitoring from two caves within the Austrian and Italian Alps. At Obir cave, Austria, D_SO₄ (×10⁵) varies between 11.1 (winter) and 9.0 (summer) and the corresponding figures for Ernesto cave, Italy, are 15.4 (winter) and 14.9 (summer). These values approximate predicted D_SO₄ values based on our chamber experiments containing both low (2 ppm) and high (20 ppm) sulphate concentrations. Our experimental values of D_SO₄ obtained at crystal growth rates typical of stalagmites, closely match those observed in other cave sites from around the world. This validates the universality of the controls behind D_SO₄ and will enhance the use of speleothem CAS as a palaeoenvironmental proxy.]]> Tue 03 Sep 2019 18:19:27 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37211 a]P) in soils. In this study, we investigated the influence of pH, EC and ageing on the extractability of B[a]P in two contracting soils (varied largely in soil texture, clay mineralogy and organic carbon content) over 4 months. Dilute sodium hydroxide (0.2 mol L^-1) and sodium chloride (0.1 mol L^-1) solutions were used to adjust soil pH and EC either separately or simultaneously. Extractability of B[a]P in these soils was monitored using a mild solvent extraction using butanol (BuOH, end-over-end shake over 24h), and an exhaustive mix-solvent extraction using dichloromethane/acetone (DCM/Ace, v:v = 1:1) facilitated by sonication and a subsequent NaOH saponification method following the DCM/Ace extraction. Results showed that increased pH and/or EC significantly increased the B[a]P extractability in the sandy soil (GIA). Variance analysis of contribution of pH and/or EC modification and ageing time on changes in B[a]P extractability indicated that in GIA > 55% and over 25% of the changes in B[a]P extractability was attributed to increased pH&EC and pH only respectively. While ageing resulted in >85% of the change in B[a]P extractability in the clayey soil (BDA), following by increased pH&EC (contribution < 15%). Large amount of non-extractable residue (NER) were formed over the ageing period, up to 95% and 79% in GIA/BDA and its modified soils, respectively. Significant correlations were observed between B[a]P BuOH extractability and the exhaustive sequential extraction using DCM/Ace followed by NaOH saponification for all soils (p < 0.001). With slopes of the correlations close to 1, our results indicated that the simple mild solvent BuOH extraction was equivalent to the complex sequential DCM/Ace and NaOH saponification extraction in these soils.]]> Thu 30 Mar 2023 09:35:27 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:49925 9.0 (k7 = 6.99 × 103 M–1·s–1). Below this pH, the formation of protonated monocarbamic acid (DMEDACOOH2) via the pathway involving DMEDAH+ and CO2(aq) becomes active and contributes to the kinetics despite the 107-fold decrease in the rate constant between the two pathways. 1H and 13C NMR spectra as a function of decreasing pH (increasing HCl concentration) at 25.0 °C have been evaluated here to confirm the protonation events in DMEDA. Calculations of the respective DMEDA nitrogen partial charges have also been undertaken to support the NMR protonation study. A comparison of the DMEDA kinetic constants with the corresponding data for piperazine (PZ) reveals that despite the larger basicity of DMEDA, the enhanced and superior kinetic performance of PZ with CO2(aq) above its predicted Bronsted reactivity is not observed in DMEDA.]]> Thu 15 Jun 2023 11:34:48 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38567 Thu 04 Nov 2021 13:51:08 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:31340 Sat 24 Mar 2018 08:44:37 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:1678 Sat 24 Mar 2018 08:30:26 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:2846 Sat 24 Mar 2018 08:27:12 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:9908 Sat 24 Mar 2018 08:07:39 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:20090 Sat 24 Mar 2018 08:00:08 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:6857 Sat 24 Mar 2018 07:47:40 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:25268 Sat 24 Mar 2018 07:38:20 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:27744 Pseudomonas sp. strain were also carried out. Results showed that after 1 and 25 d, HPCD at pH 7 extracted significantly more View the MathML source14C-phenanthrene (p<0.05)(p<0.05) from BC-amended soils than the other two solutions (un-buffered and pH 8), while HPCD at pH 8 extracted statistically similar (p>0.05)(p>0.05) amounts of phenanthrene compared to the un-buffered solution. At 50 d, HPCD at pH 8 generally extracted more ¹⁴C-phenanthrene from all treatments. It was proposed that higher pH promoted the dissolution of soil organic matter (SOM), leading to a greater solubility of phenanthrene in the solvent phase and enhancing the extractive capability of HPCD solutions. Although correlations between extractability and biodegradability of ¹⁴C-phenanthrene in BC-amended soils were poor, increasing pH was demonstrated a viable approach to enhancing HPCD extractive capability for the ¹⁴C-PAH from soil with BC.]]> Sat 24 Mar 2018 07:27:45 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:24087 Corymbia maculata. The higher rate of fertilizer addition improved seedling establishment of Mimosaceae and the survival of Myrtaceae species. High nutrient treatments increased weed and grass densities, which may have reduced the nutrient benefit for native species. In conclusion, biosolids and the high rate of fertilizer application ameliorated the nitrogen and phosphorus deficiency of spoil to support growth and survival of reintroduced native species. However, potential benefits were attenuated by competition from accompanying weed growth that could be managed by implementing a control program.]]> Sat 24 Mar 2018 07:11:47 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:24070 + with metal ions to the surface sites and a decrease in metal ion precipitation as hydroxides at high pH levels. In addition, the heavy metal retention isotherm over a wide range of concentrations for the bentonite follows Temkin and Langmuir adsorption models while Freundlich and Langmuir models for the kaolin. Interestingly, at a high concentration of 10 mM, the Pb precipitation unlikely occurs in the presence of both clays tested over a wide range pH level (< 10), whereas it likely takes place in case of Cu and Zn.]]> Sat 24 Mar 2018 07:09:39 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:27512 Mon 23 Sep 2019 14:23:33 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:33636 Mon 23 Sep 2019 12:18:04 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:36868 Mon 13 Jul 2020 16:18:46 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51936 Fri 22 Sep 2023 12:38:22 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:43401 Fri 16 Sep 2022 09:58:33 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:39990 2 in aqueous amine solutions.]]> Fri 15 Jul 2022 10:18:18 AEST ]]>