National Measurement Laboratory

<strong class="journal-contentHeaderColor">Abstract.</strong> <span style="font-weight: 400;">The Southern Ocean plays a vital role in regulating Earth&rsquo;s climate by absorbing large quantities of carbon dioxide, but its productivity is strongly limited by the availability of iron needed for phytoplankton growth. Sea ice is a crucial seasonal reservoir of iron; however, the processes responsible for its enrichment remain poorly understood. Here we use a process-based model to show that frazil ice formation, a common feature of winter sea-ice growth in the Southern Ocean, can scavenge dissolved iron from seawater and concentrate it in newly formed ice. First-order estimates scaled to the Antarctic sea-ice zone suggest that frazil-origin ice could supply ~16&ndash;33% of the seasonal dissolved iron pool in the upper 10 m. Because this iron is released as a short-lived but intense pulse upon melt, frazil ice provides a pathway that can trigger phytoplankton blooms, linking polar sea-ice processes directly to global carbon cycling.</span>

Societal Impact StatementCollections of dried plant specimens (herbaria) provide an invaluable resource for the study of many areas of scientific interest and conservation globally. Digitisation increases access to specimens and metadata, enabling efficient use across a broad spectrum of research. The value of physical specimens is enhanced by digitisation, but these specimens remain fundamental for the study of traits not yet captured digitally. We investigate the requirements for physical access and the curation and facilities needed to maximise specimen use and value. We present recommendations to ensure that specimens and data are both fully accessible to support research into global challenges.SummaryHerbarium management has traditionally focused on providing direct access to the physical specimens, but this scope must now expand to also embrace digital collections. Advances in technologies such as artificial intelligence and high‐throughput genomics are increasing the amount of information that can be extracted from specimens, and it is becoming commonplace to provide digital access to specimen images and collection metadata. These developments are facilitating the use of herbarium collections to inform conservation planning and in studies plant and fungal taxonomy, distribution and evolution. This paper examines how herbaria are transitioning from physical specimen‐centric collection management practices to increasingly digitised curation, and the effects that digital availability of data are having on demands for physical access. We provide a set of recommendations to institutions holding herbarium collections. We emphasise the critical importance of further digitising herbaria of all sizes; the need to ensure that historical inequalities in deposition of specimens are not perpetuated; and that the capacity to utilise new technologies must be further developed, especially in biodiverse regions from which most herbarium collections are derived.To improve access to collection data, herbarium managers need to more rigorously adopt community‐agreed data standards, and more strongly support open access platforms such as the Global Biodiversity Information Facility either directly or through regional coalitions. As digitisation and open data access increase, herbaria will need to offer users with seamless hybrid access to physical and digital records while continuing to develop their collections to advance research and conservation.

Ensuring a sustainable future for the global ocean requires meaningful dialogue and engagement with society. Around the world, efforts to engage and collaborate with society increasingly emphasise ocean literacy as a potential tool for engaging and educating people on ocean issues. A conceptual measure of people’s awareness, attitudes, and behaviours towards the ocean, ocean literacy has been highlighted as a key objective in recent ocean sustainability agreements and initiatives, including the UN Decade of Ocean Science for Sustainable Development. In Australia, research and applied interest in ocean literacy is burgeoning. It is therefore timely to take stock and explore recent work that may inform future pathways towards supporting and engaging society in achieving ocean sustainability. Here, we explore examples of ocean literacy research and practice in Australia, to develop prospective thinking on inter/transdisciplinary approaches for advancing ocean literacy under sustainability objectives. In doing so, we anticipate the next steps for progressing ocean literacy in the Australian context, including supporting ocean learning and education, engaging communities at all levels, fostering cross‐sector collaboration on connecting people to the ocean, and building strong and actionable policy and funding frameworks to ensure long‐term impact. We emphasise the need to collaboratively develop a national ocean literacy strategy to guide and structure these efforts and to establish an Australian ocean literacy coalition to facilitate research, cross‐sector collaboration, and implementation in practice.

Abstract SignificanceA new platform/device is presented that advances hybrid diffuse optical monitors closed to clinical practice, bridging the gap between research-grade optical systems and practical bedside applications. Traditional devices often lack automation, multi-parameter functionality, and operator independence, hence, limiting their usability in demanding clinical environments. By offering automation, user-friendly operation, and overcoming the typical limitations of continuous-wave near-infrared spectroscopy, the hybrid diffuse optical platform (hDOS) provides a more accurate and reliable assessment of both oxygenation and perfusion. This innovation is particularly valuable for monitoring critically ill patients, where precise real-time measurements can directly influence patient management and outcomes.AimTo design, validate, and characterize the platform hDOS that integrates time-domain near-infrared spectroscopy, diffuse correlation spectroscopy, and a pulse oximeter with an automated vascular occlusion test (VOT). The platform aims to support continuous monitoring and the assessment of peripheral microvascular, and metabolic functions in both clinical and field settings.ApproachThe validation strategy for the hDOS device follows a comprehensive approach that goes beyond conventional optical performance assessments. Rather than solely verifying fundamental system parameters, the evaluation comprises of real-world usability, operator and patient safety, and clinical implementation. The device’s precision and usability were rigorously testedin vivothrough test-retest measurements and comparisons with a commercially available device (INVOS 5100C). This was subsequently followed by a seven-month clinical evaluation at Parc Taulí Hospital Universitari.ResultsThe device underwent extensive validation, accumulating over 200 hours of usage across approximately 150 measurement sessions. The hDOS device exhibited two-fold lower inter-subject and intra-subject variability in baseline tissue oxygen saturation compared to the INVOS 5100C. Furthermore, during a a vascular occlusion challenge, statistically significant differences were observed between the two systems across all extracted parameters. Finally, as a proof of concept, hDOS successfully detected differences in the microvasculature between a general mixed ICU patient cohort (n= 100) and a healthy control group (n= 37).ConclusionsOverall, hDOS device has performed well in both bench-top and realistic clinical applications on patientsin vivo. hDOS device provides a unique combination of parameters, available for the first time in a fully automated, self-contained platform.

Natural gas (NG) is one of the most important sources of energy for industrial and domestic consumption in the present era because it is cheap and free from sulfur impurities. The processed natural gas consists of methane (main constituent), ethane, propane, and hydrocarbons of heavier molecular masses as well as other gases such as nitrogen, helium, and water vapor. Therefore, accurate and precise measurement of its composition is of fundamental importance for trade reasons. To improve the quality of natural gas measurements, certified reference materials (CRMs) should be used for the calibration of measuring equipment in order to ensure the traceability of the measurement results to the SI units. In the present article, the aim was to prepare and certify a natural gas mixture composed of, helium, hydrogen, nitrogen, methane, ethane, pro-pane, iso-butane, n-butane, iso-pentane, n-pentane and n-hexane. For traceability purposes, a multi-component natural gas mixture was prepared gravimetrically as a reference material according to ISO 6142 from pure helium, hydrogen, n-pentane, i-pentane, n-butane, i-butane, propane, ethane, hexane, methane, and nitrogen. The preparation was done in two dilution steps in 5 L aluminum cylinders. The calculated mole fractions and associated uncertainties of natural gas components were verified by a dual gas chromatography system equipped with a flame ionization detector and thermal conductivity detector (GC-FID/TCD) in accordance with ISO 6143. The GC system was calibrated by a series of primary gas mixtures (CRMs) produced by the National Metrology Institute, NMI. The results obtained by gravimetry and by GC measurements have been checked for compatibility as required by ISO 6142 and were found in very good agreement. Details of the preparation and calculation of the mole fractions and uncertainties of all gas components are explained in this article. The produced natural gas CRM is very important for gas analytical laboratories in calibration and quality control purposes.

Ensuring metrological traceability and result validity is a critical aspect of testing laboratories to obtain reliable results and ensure comparability. A survey was conducted in testing laboratories to assess the extent of traceability and result validity assurance through the utilization of certified reference materials and the implementation of quality assurance. The objective of this survey is to determine the necessary types of reference materials and proficiency tests, particularly for air and exhaust gas laboratories, in order to enhance the development of reference materials and proficiency testing services. The survey involved distributing a questionnaire regarding the utilization of certified reference materials and the implementation of quality assurance to accredited air and exhaust gas testing laboratories. The findings revealed that out of the 25 participating laboratories, a significant portion had not yet incorporated the use of certified reference materials in their testing processes. Although internal quality control measures were generally implemented across laboratories, only 40% had adopted external quality control methods, such as comparative and proficiency tests. Consequently, it is evident that there is an urgent need to develop reference materials for all parameters of air and exhaust gas testing, and there is a requirement for updated information for proficiency test providers.

A simple liquid-liquid extraction (LLE) procedure and liquid chromatography-tandem mass spectrometer (LC-MS/MS) were validated to analyze the residues of diflubenzuron and novaluron in tomatoes.Validation criteria included; linearity in the range of 2-100 g.kg -1 and 5-200 g.kg -1 with a correlation coefficient (R 2 ) of 0.998, trueness (% recovery) of 90.55-97.51%at spiking levels of 10, 100, and 1000 mg.kg -1 , the limit of detection (LOD) of 0.46 and 3.22 g.kg -1 , the limit of quantitation (LOQ) of 5 and 10 g.kg -1 , intraday repeatability (RSD r ) of 9.31% and 6.63%, and inter-day repeatability (RSD R ) of 13.72% and 8.87%, respectively for diflubenzuron and novaluron.Due to the matrix effect, negligible enhancement in instrument response was observed for the tested analytes.The dissipation behaviour of diflubenzuron (24 % SC) and novaluron (10 % EC) in greenhouse tomatoes after treatment with 192 and 40 g a.i.ha-1 (authorized dosage) and 336 and 80 g a.i.ha-1 (high dosage) was investigated.Dissipation kinetics were best fitted to the first-order reaction.Despite the application dose for novaluron being about three times smaller compared to diflubenzuron, the residues of novaluron dissipated more rapidly than those of diflubenzuron with constant rates (k) of 0.342-0.356and 0.194-0.154day-1 and half-lives (t0.5) of 1.77-1.73and 3.57-4.49days respectively, at the doses tested.The terminal residues of diflubenzuron and novaluron were 0.013-0.328and 0.011-0.171mg.kg-1 after 2 and 3 times application, respectively.The calculated risk quotients were less than 1, indicating that spraying tomatoes with the tested insecticides at the applied doses poses no significant potential risks to Saudi consumers.