Accelerator mass spectrometry measurements of 233U in groundwater, soil and vegetation at a legacy radioactive waste site

Low-level radioactive wastes were disposed at the Little Forest Legacy Site (LFLS) near Sydney, Australia between 1960 and 1968. According to the disposal records, 233U contributes a significant portion of the inventory of actinide activity buried in the LFLS trenches. Although the presence of 233U in environmental samples from LFLS has been previously inferred from alpha-spectrometry measurements, it has been difficult to quantify because the 233U and 234U α-peaks are superimposed. Therefore, the amounts of 233U in groundwaters, soils and vegetation from the vicinity of the LFLS were measured using accelerator mass spectrometry (AMS). The AMS results show the presence of 233U in numerous environmental samples, particularly those obtained within, and in the immediate vicinity of, the trenched area. There is evidence for dispersion of 233U in groundwater (possibly mobilised by co-disposed organic liquids), and the data also suggest other sources of 233U contamination in addition to the trench wastes. These may include leakages and spills from waste drums as well as waste burnings, which also occurred at the site. The AMS results confirm the historic information regarding disposal of 233U in the LFLS trenches. The AMS technique has been valuable to ascertain the distribution and environmental behaviour of 233U at the LFLS and the results demonstrate the applicability of AMS for evaluating contamination of 233U at other radioactive waste sites.

Radiocarbon (14C) accelerator mass spectrometry as a convenient tool for differentiation of flavor chemicals of synthetic origin from biobased sources and their in-vivo toxicity assessment

Plants are known to be the natural factory for the production of flavor chemicals. Essential oils comprised of aldehyde as a functional group are potent in deciphering flavor effects in beverages and fresh and prepared food products. In the majority, these are manufactured through synthetic routes, resulting in high product carbon footprints or CO2 equivalents in total greenhouse gas emission. FDA has banned some of the synthetic flavor chemicals due to the health hazards associated with them. However, consumer's preference for natural is at stake due to the absence of quantitative traceability tools. The accelerator mass spectrometer (AMS) analysis revealed a distinction between natural and fossil-derived citral and its blends in Cymbopogon essential oils. The plant-derived citral contained a percent modern carbon (pMC) value in the range of 99-100 %. In contrast, the fossil fuel-derived citral showed zero pMC. Similarly, blends of Cymbopogon oils with 30-50 % (w/w) of fossil origin citral contained pMC equivalent to the proportions of modern carbon. These results showed the usefulness of AMS in quantifying the amount of 14C associated with flavor ingredients. Besides, acute oral toxicity data revealed Cymbopogon oils as the safe flavoring substance at the highest 2000 mg/kg body weight dose in Swiss albino mice.

Meeting report of the 4th European biotransformation workshop

1. Challenges, strategies and new technologies in the field of biotransformation were presented and discussed at the fourth European Biotransformation Workshop which was held in collaboration with the joint ISSX/DMDG meeting on June 15, 2023 at the University of Hertfordshire in Hatfield, UK.2. In this meeting report we summarise the presentations and discussions from this workshop.3. The topics covered are listed below:Unusual biotransformation reactionsBiotransformation Workflows in Discovery utilising various softwares for structure elucidationBiotransformation software for the identification of peptide metabolitesAccelerator Mass Spectrometry (AMS) for endogenous and xenobiotic metabolite profilingMetabolite profiling using quantitative Nuclear magnetic resonance (NMR) and liquid chromatography coupled to inductively coupled plasma-mass spectrometry (LC-ICP-MS).

Pupillometry as a new window to player fatigue? A glimpse inside the eyes of a Euro Cup Women's Basketball team

A rapidly emerging area of interest in high-pressure environments is that of pupillometry, where handheld quantitative infrared pupillometers (HQIPs) are able to track psycho-physiological fatigue in a fast, objective, valid, reliable, and non-invasive manner. However, the application of HQIPs in the context of athlete monitoring is yet to be determined. Therefore, the main aim of this pilot study was to examine the potential usefulness of a HQIP to monitor game-induced fatigue inside a professional female basketball setting by determining its (1) test-retest repeatability, (2) relationship with other biomarkers of game-induced fatigue, and (3) time-course from rested to fatigued states. A non-ophthalmologic practitioner performed a standardized Pupil Light Reflex (PLR) test using a medically graded HQIP among 9 professional female basketball players (2020-2021 Euro Cup) at baseline, 24-h pre-game (GD-1), 24-h post-game (GD+1) and 48-h post-game (GD+2). This was repeated over four subsequent games, equalling a total of 351 observations per eye. Two out of seven pupillometrics displayed good ICCs (0.95-0.99) (MinD and MaxD). Strong significant relationships were found between MaxD, MinD, and all registered biomarkers of game-induced fatigue (r = 0.69-0.82, p < 0.05), as well as between CV, MCV, and cognitive, lower-extremity muscle, and physiological fatigue markers (r = 0.74-0.76, p < 0.05). Three pupillometrics were able to detect a significant difference between rested and fatigued states. In particular, PC (right) (F = 5.173, η2 = 0.115 p = 0.028) and MCV (right) (F = 3.976, η2 = 0.090 p = 0.049) significantly decreased from baseline to GD+2, and LAT (left) (F = 4.023, η2 = 0.109 p = 0.009) significantly increased from GD-1 to GD+2. HQIPs have opened a new window of opportunity for monitoring game-induced fatigue in professional female basketball players. However, future research initiatives across larger and heterogenous samples, and longer investigation periods, are required to expand upon these preliminary findings.

Optimizing prophylactic antibiotic use among surgery patients in Ethiopian hospitals

BACKGROUND

Since 2018, the Ethiopian Ministry of Health (MOH) has been working to institutionalize antimicrobial stewardship (AMS) programs across the country. The US Agency for International Development Medicines, Technologies, and Pharmaceutical Services Program supported Ethiopia's multipronged One Health approach to combat AMR. The objective of this paper was to evaluate the effect of a quality improvement intervention to optimize the use of antimicrobials for surgical prophylaxis.

METHODS

Basic AMS interventions were introduced in five hospitals from January to May 2023. The AMS committees and multidisciplinary teams working at the surgical wards were trained and provided on-site support to implement surgical antibiotic prophylaxis (SAP) interventions. A before-after comparison was made for 206 medical records at baseline and 213 during the intervention phase. Qualitative data were gathered through discussions during experience-sharing workshops to supplement the quantitative results.

RESULT

There were improvements in the presurgery dose of the prophylactic antibiotic and its timing: the doses within the recommended range increased from 11.2 % to 61.0 % (p < 0.001) and the optimal timing increased from 68 % to 82.6 % (p < 0.001). The hospitals also demonstrated some nonsignificant improvement in the duration of prophylactic antibiotic use (from 35 % to 44.6 % [p = 0.106]), with change in practice hampered by practitioners' resistance to early discontinuation for fear of infection due to perceived weaknesses in infection prevention and control practices. Nonavailability of the recommended antibiotic of choice for surgical prophylaxis was another major challenge in addressing all the elements of SAP. The intervention demonstrated a significant antibiotic-related average cost saving, 51.8 Ethiopian birr (∼1 US dollar) per patient (p = 0.028).

CONCLUSION

Short-term investments with basic AMS interventions can help to improve SAP use in surgical wards. However, comprehensive success requires complementing AMS interventions with concurrent attention to proper supply chain and infection prevention and control.

Proposed methods for estimating loss of saleable milk in a cow-calf contact system with automatic milking

Cow-calf contact (CCC) systems, although beneficial in many respects, introduce additional challenges to collect reliable data on milk production, which is important to assess individual cow efficiency and dairy farm profitability. Apart from weighing calves before and after each feeding, the amount of saleable milk lost due to calf suckling is practically impossible to measure. Here, we assess 2 indirect methods for estimating loss of saleable milk when housing cows and calves together in a robotic milking unit. In our study, treatment (CCC) cows and calves were kept together full time until the calves were 127 ± 6.6 d old (mean ± SD). Control cows were separated from their calves within 12 h of birth and then kept in the same unit as the treatment cows but with no access to either their own or treatment calves. Milk yield recording of both groups was performed from calving until pasture release at 233 ± 20 d in milk. The first estimation method relied on observed postseparation milk yield data, which were fed into a modified Wilmink regression model to determine the best-fitting lactation curve for the preseparation period. The second method was based on the cows' daily energy intake postseparation, calculated by measuring the daily feed intake and analyzing the energy content of the ration. The calculated energy intake was used to determine the average ratio between energy intake and the observed milk yield the following day for each individual cow, assuming constant rates of mobilization and deposition of body fat. The obtained ratio was then used to calculate the expected daily milk yield based on daily energy intake data during the preseparation period. In this paper, we analyzed data from 17 CCC cows kept together with their calves and 16 control cows; both groups calved from September to October 2020 and were followed up until release to pasture in May 2021. Saleable milk yield was lower in CCC cows than in control cows, both before and after separation. The 2 methods were used on data for control cows and showed milk yield loss using the lactation curve method (average of -3.4 ± 2.8 kg/d) and almost no loss using energy intake data (average of -1.4 ± 2.7 kg/d). Milk yield loss for CCC cows was estimated at average 11.3 ± 4.8 and 7.3 ± 6.6 kg milk/d, respectively. The proposed lactation curve estimation method tends to overestimate milk yield loss, whereas the method based on energy intake is more accurate. However, collecting detailed energy intake data per individual cow requires additional effort and equipment, which is not always feasible on commercial farms. Further research is needed to improve milk loss estimation and to better understand trade-offs in CCC systems.

Acute Mountain Sickness and High Altitude Cerebral Edema in Women: A Scoping Review-UIAA Medical Commission Recommendations

Derstine, Mia, Dominique Jean, Beth A. Beidleman, Jacqueline Pichler Hefti, David Hillebrandt, Lenka Horakova, Susi Kriemler, Kasté Mateikaité-Pipiriené, Peter Paal, Alison Rosier, Marija Andjelkovic, and Linda E. Keyes. Acute mountain sickness and high altitude cerebral edema in women: A scoping review-UIAA Medical Commission recommendations. High Alt Med Biol. 24:259-267, 2023. Background: Acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) are illnesses associated with rapid ascent to altitudes over 2,500 m in unacclimatized lowlanders. The aim of this scoping review is to summarize the current knowledge on sex differences in the epidemiology, pathophysiology, symptomatology, and treatment of AMS and HACE, especially in women. Methods and Results: The UIAA Medical Commission convened an international author team to review women's health issues at high altitude and to publish updated recommendations. Pertinent literature from PubMed and Cochrane was identified by keyword search combinations (including AMS, HACE, and high altitude), with additional publications found by hand search. The primary search focus was for articles assessing lowland women sojourning at high altitude. Results: The literature search yielded 7,165 articles, 37 of which were ultimately included. The majority of publications included did not find women at increased risk for AMS or HACE. There was extremely limited sex-specific data on risk factors or treatment. Conclusions: There is a limited amount of data on female-specific findings regarding AMS and HACE, with most publications addressing only prevalence or incidence with regard to sex. As such, general prevention and treatment strategies for AMS and HACE should be used regardless of sex.

A descriptive study of vancomycin use at Red Cross War Memorial Children's Hospital, Cape Town

Background

Antimicrobial stewardship principles guide the clinical use of antimicrobials, including vancomycin, but paediatric vancomycin prescribing practices have not been evaluated in South Africa.

Objectives

To document the use, prescribing practices and monitoring of intravenous vancomycin and the spectrum of bacteria isolated on microbiological culture in children treated with intravenous vancomycin during a 12-month period at Red Cross War Memorial Children's Hospital (RCWMCH).

Method

A retrospective audit of intravenous vancomycin use in children admitted to RCWMCH during 2019 was performed.

Results

All 158 vancomycin prescription episodes for 143 children were included. Overall usage of intravenous vancomycin was 63 days of therapy per 1000 patient days (interquartile range [IQR]: 38-72). The median starting dose was 15 mg/kg per dose (IQR: 14-15) and median daily dose was 45 mg/kg per day (IQR: 43-60). Vancomycin was prescribed as empiric (127/158, 80%) and directed (31/158, 20%) treatment. The median duration of treatment for the directed group (7 days) was longer than the empiric group (4 days) (p = 0.001). Vancomycin serum trough concentrations were performed in 65/98 (66%) episodes where vancomycin treatment exceeded 3 days, with only 16/65 (25%) of these samples obtained before the fourth dose. Prolonged antibiotic treatment of 14 days or more was not associated with Gram-positive bacteria on culture (odds ratio [OR]: 1.02, 95% confidence interval [CI]: 0.17-4.2).

Conclusion

Dosing errors, prolonged empiric treatment and inappropriate vancomycin monitoring were problems associated with vancomycin prescriptions.

Contribution

The study identified multiple opportunities for improved vancomycin prescribing and monitoring. Further research and implementation of improved prescribing practices could contribute to the preservation of vancomycin as an effective antibiotic.

Tackling antimicrobial resistance: developing and implementing antimicrobial stewardship interventions in four African commonwealth countries through a health partnership model

In recent years, health partnerships have shared infection prevention and control innovations between United Kingdom hospitals and Low-Middle-Income Countries. However, none had focused on antimicrobial stewardship (AMS), a core component of tackling antimicrobial resistance (AMR). This paper documents an effective approach to developing a program to increase AMS capacity in four African countries: Ghana, Tanzania, Uganda, and Zambia as part of the Commonwealth Partnerships for Antimicrobial Stewardship (CwPAMS) program. A systematic approach was applied to assess gaps in AMS interventions and inform the development of the CwPAMS program through deskbased assessments, including National Action Plans on AMR, online focus group meetings, and expert advisory group reviews. Twelve partnerships were selected for the CwPAMS program. AMS support tools were developed based on recommendations from the scoping, including an AMS checklist tool, a healthcare worker knowledge and attitudes questionnaire, and an antimicrobial prescribing app to support clinical decision-making. Training workshops on AMS were developed and delivered to volunteers in Africa and the UK using a train-the-trainer model. The tools and workshops facilitated capacity building for AMS through the generation and strengthening of knowledge, skills, commitment, structures, systems, and leadership among stakeholders in the UK and Africa. The overall average rating assigned to the program following independent evaluation using the Organisation for Economic Cooperation and Development Assistance Committee Evaluation Criteria was very good. The evaluation also highlighted that the majority of the HPs (75%) focused on AMS and/or improved prescribing practice; all HPs have developed and implemented AMS strategies, guidelines, and tools within their hospitals; and NHS staff were able to translate the knowledge and skills they had received early on in the program into clinical practice in response to COVID-19 challenges.

Restricting access to antibiotics: The effectiveness of a 'no repeats' government policy intervention

BACKGROUND

Australia has a high rate of antibiotic use. Government policy interventions are one strategy to optimise the use of antibiotics. On 1 April 2020, the Australian Government Department of Health introduced a policy intervention to increase the quality use of four antibiotics.

OBJECTIVES

To assess if the government policy intervention improved the appropriate supply of the four antibiotics amoxicillin, amoxicillin-clavulanic acid, cefalexin and roxithromycin.

METHOD

This study employed a retrospective cohort study design comparing a 10% sample (n = 345,018) of four antibiotics prescribed and dispensed in Australia during a three-month period (May, June, July) in 2019, and again in 2020 (after the policy intervention). The 10% sample of PBS data was obtained from the Australian Government Department of Health. Descriptive statistics, bivariate and multivariable logistic regression analysis were carried out.

RESULTS

The results suggest the policy change improved the appropriate supply of original prescriptions in 2020 compared to 2019 OR = 1.75 (95% CI = 1.68-1.82, p < 0.001), and appropriate supply of repeat prescriptions OR = 1.56 (95% CI = 1.25-1.96, p < 0.001). In 2020, the proportion of appropriate supply of original prescriptions increased by an absolute difference of 1.8% (95% CI = 1.6-1.9%; P < 0.001), and appropriate supply of repeat prescriptions increased by 3.9% (95% CI = 2.2-5.5%; P < 0.001). The total number of antibiotic prescriptions prescribed and dispensed in 2019 (N = 219,960) reduced in 2020 (N = 125,058) after the policy intervention.

CONCLUSION

The study provides evidence for the impact of a government policy intervention to improve the appropriate supply of antibiotics, although some of the reduction in antibiotic use was likely due to the concomitant COVID-19 pandemic. Further research is required to assess the impact of the intervention outside a pandemic.

Molecular tracers, mass spectral tracers and oxidation of organic aerosols emitted from cooking and fossil fuel burning sources

Secondary organic aerosol (SOA) composes a substantial fraction of atmospheric particles, yet the formation and aging mechanism of SOA remains unclear. Here we investigate the initial oxidation of primary organic aerosol (POA) and further aging of SOA in winter Beijing by using aerosol mass spectrometer (AMS) measurements along with offline molecular tracer analysis. Multilinear engine (ME-2) source apportionment was conducted to capture the characteristic of source-related SOA, and connect them with specific POA. Our results show that urban cooking and fossil fuel burning sources contribute significantly (17 % and 20 %) to total organic aerosol (OA) in winter Beijing. Molecular tracer analysis by two-dimensional gas chromatography-time-of-flight mass spectrometer (GC × GC-ToF-MS) reveals that cooking SOA (CSOA) is produced through both photooxidation and aqueous-phase processing, while less oxidized SOA (LO-SOA) is the photooxidation product of fossil fuel burning OA (FFOA) and may experience aqueous-phase aging to form more-oxidized oxygenated OA (MO-OOA). Furthermore, CHO_{m/z 69} and CHO_{m/z 85} are mass spectral tracers indicating the initial photooxidation, while CHO₂⁺ and C₂H₂O₂⁺ imply further aqueous-phase aging of OA. Tracer analysis indicates that the formation of diketones is involved in the initial photooxidation of POA, while the formation of glyoxal and diacids is involved in the further aqueous-phase aging of SOA.

Comparison of AMS, TIMS, and SIMS techniques for determining uranium isotope ratios in individual particles

The determination of isotope ratios in individual uranium particles is very important for nuclear safeguards. In this work, accelerator mass spectrometry (AMS), thermal ionization mass spectrometry (TIMS), and secondary ion mass spectrometry (SIMS) were applied to isotope ratio analysis of individual uranium particles and compared in terms of background, measurement accuracy, and efficiency. Several individual uranium particles (1-7 μm) from certified reference materials were used as samples. The results show that the average values of blank counting rate of ²³⁵ U for AMS, FT-TIMS (FT: fission track), SEM-TIMS (SEM: scanning electron microscope), and SIMS were 7.3, 7.8, 2.7 and 2.2 cps, respectively. The relative error of ²³⁴ U/²³⁵ U and ²³⁴ U/²³⁶ U isotope ratios of the particles from U200 for AMS were within 10% and 20%, whereas the results of FT-TIMS and SIMS were within 5% and 10%, respectively. The relative error and external precision of ²³⁴ U/²³⁸ U and ²³⁵ U/²³⁸ U of the particles from U850 for the method of AMS, SEM-TIMS, and SIMS were within 10% and 5%, respectively. For ²³⁶ U/²³⁸ U, the average values of the relative error and external precision measured by AMS were within 5%, which measured by SEM-TIMS and SIMS were all within 10%. AMS has advantages in measuring ²³⁶ U/²³⁸ U. The measurement time of AMS and SEM-TIMS was shorter than that of FT-TIMS and longer than that of SIMS. It is considered that AMS and SEM-TIMS have a certain development prospect, and it is necessary to research deeply.

Meeting report of the 3rd European Biotransformation Workshop

Challenges, strategies and new technologies in the field of biotransformation were presented and discussed at the 3rd European Biotransformation Workshop which was held in collaboration with the DMDG on 5-6 October 2022 in Amsterdam. In this meeting report we summarise the presentations and discussions from this workshop. The topics covered are listed below:Accelerator mass spectrometry (AMS) for the support of microtracer studiesBiotransformation of the novel myeloperoxidase inhibitor AZD4831 in preclinical species and humansAMS in biotransformation studies: unusual case studiesDiscussion on new FDA draft guidance and AMSMultimodal molecular imaging and ion mobility applications in drug discovery and developmentMetabolites in Safety Testing considerations for large molecules.

The interplays among meteorology, source, and chemistry in high particulate matter pollution episodes in urban Shanghai, China

High particulate matter (PM) pollution episodes still occur occasionally in urban China, despite of improvements in recent years. Investigating the influencing factors of high-PM episodes is beneficial in the formulation of effective control measures. We herein present the effects of weather condition, emission source, and chemical conversion on the occurrence of high-PM episodes in urban Shanghai using multiple online measurements. Three high-PM episodes, i.e., locally-accumulated, regionally-transported, and dust-affected ones, as well as a clean period were selected. Stagnant air with temperature inversion was found in both locally-accumulated and regionally-transported high-PM episodes, but differences in PM evolution were observed. In the more complicated dust-affected episode, the weather condition interacted with the emission/transport sources and chemical conversion, resulting in consecutive stages with different PM characteristics. Specifically, there were (1) stronger local accumulation in the pre-dust period, (2) dust-laden air with aged organic aerosol (OA) upon dust arrival, (3) pollutants being swept into the ocean, and (4) back to the city with aged OA. Our results suggest that (a) local emissions could be rapidly oxidized in some episodes but not all, (b) aged OA from long-range transport (aged in space) had a similar degree of oxygenation compared to the prolonged local oxidation (aged in time), and (c) OA aged over land and over the ocean were similar in chemical characteristics. The findings help better understand the causes and evolution of high-PM episodes, which are manifested by the interplays among meteorology, source, and chemistry, providing a scientific basis for control measures.

Retrospective determination of fallout radionuclides and 236U/238U, 233U/236U and 240Pu/239Pu atom ratios on air filters from Vienna and Salzburg, Austria

137Cs and 241Pu (via 241Am) concentrations were measured γ-spectrometrically on air filters from the early 1960s (mainly from 1964-66) from Vienna, Austria, and an alpine station in Salzburg, Austria. Accelerator mass spectrometry (AMS) was used to determine 240Pu/239Pu, 236U/238U and 233U/236U atom ratios as well as 236U, 239Pu and 240Pu atom concentrations. The maximum 236U/238U atom ratio of these unique undisturbed global fallout samples was (1.19 ± 0.31) × 10-5 in spring 1964. The 233U/236U atom ratios were found within (0.15-0.49) × 10-2 and indicate that the weapons tests of the early 1960s can be excluded as 233U source. The 236U/239Pu atom ratios were calculated in the range of 0.22-0.48.

Retrospective determination of U and Pu isotopes and atom ratios in lung samples from Vienna, Austria

Uranium and plutonium isotope concentrations as well as ²³⁶U/²³⁸U and ²⁴⁰Pu/²³⁹Pu atom ratios were measured by AMS in human lung samples from the early 1960s. The ²³⁶U concentrations as well as the ²³⁶U/²³⁸U atom ratios show a maximum in 1964, ²³⁹Pu and ²⁴⁰Pu concentrations are increasing continually from 1962 to 1965. ²³⁶U/²³⁸U atom ratios are lower by two orders of magnitude compared to corresponding aerosol data from Vienna, probably due to older ²³⁸U deposited in the lungs, enhanced ²³⁸U concentrations in the city air, and activity partition within different particle sizes. The ²³⁶U/²³⁹Pu atom ratios in lung samples are also lower than expected from the aerosol data, while ²⁴⁰Pu/²³⁹Pu atom ratios lie well within the range typical for nuclear bomb fallout.

Sequential scavenging and measurement of seawater radiocesium concentrations and plutonium isotopic ratios offshore Fukushima

The scientific interest in radiocesium and plutonium found in the oceans and seas has increased enormously in the past years as a consequence of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident and is expected to be ongoing due to many unresolved questions. Hence, continuous development of new and verification of old analytical methods should be at the top of the list of the community, working on the topic. In this study, we processed and analyzed several seawater samples, collected in different time frames (2011-2015) from the North Pacific Ocean offshore Fukushima, to determine their radiocesium activities, ¹³⁴Cs/¹³⁷Cs activity ratios and ²⁴⁰Pu/²³⁹Pu isotopic ratios using the sequential scavenging method, gamma spectrometry and accelerator mass spectrometry (AMS). The observed radiocesium levels in seawater (0.07-0.042 Bq L^-1) clearly indicated that the investigated region remained impacted by releases from the damaged power plant even after four years after the accident. Regarding plutonium, its successful separation from large volume seawater samples was confirmed by detection of ²⁴⁰Pu by AMS. However, several problems emerged during the analyzes, which we tried to address with the use of additional methods (e.g., measurements of uranium by ICPMS). The efficiencies of the applied methods and other issues are also discussed.

Sporophytic control of pollen meiotic progression is mediated by tapetum expression of ABORTED MICROSPORES

Pollen development is dependent on the tapetum, a sporophytic anther cell layer surrounding the microspores that functions in pollen wall formation but is also essential for meiosis-associated development. There is clear evidence of crosstalk and co-regulation between the tapetum and microspores, but how this is achieved is currently not characterized. ABORTED MICROSPORES (AMS), a tapetum transcription factor, is important for pollen wall formation, but also has an undefined role in early pollen development. We conducted a detailed investigation of chromosome behaviour, cytokinesis, radial microtubule array (RMA) organization, and callose formation in the ams mutant. Early meiosis initiates normally in ams, shows delayed progression after the pachytene stage, and then fails during late meiosis, with disorganized RMA, defective cytokinesis, abnormal callose formation, and microspore degeneration, alongside abnormal tapetum development. Here, we show that selected meiosis-associated genes are directly repressed by AMS, and that AMS is essential for late meiosis progression. Our findings indicate that AMS has a dual function in tapetum-meiocyte crosstalk by playing an important regulatory role during late meiosis, in addition to its previously characterized role in pollen wall formation. AMS is critical for RMA organization, callose deposition, and therefore cytokinesis, and is involved in the crosstalk between the gametophyte and sporophytic tissues, which enables synchronous development of tapetum and microspores.

The teat cup detachment level affects milking performance in an automatic milking system with teat cleaning and milking in the same teat cup

The goal of the present study was to determine the best quarter milk flow for teat cup detachment depending on lactational stage and milking interval to optimize the milking process in automatic milking systems (AMS). Milking characteristics and post-milking teat condition were recorded in an AMS with all actions from teat cleaning to post-milking teat dipping occurring in the same teat cup and liner (GEA DairyRobot R9500). In 24 dairy cows, 12 in early (<80 DIM) and 12 in late lactation (>180 DIM), 294 milkings were recorded during 12 consecutive days. Teat cup detachment was set at a quarter milk flow of 50, 87.5 or 125 g/min. Voluntary milking intervals varied similarly in cows in early (6.1-14.8 h) and late lactation (6.3-15.7 h). Total milk yield, milk production per h and average milk flow were higher in early than in late lactation cows. Total milk yield per milking did not differ between detachment levels. The mean milking time was reduced by up to 1.5 min at the highest compared to the lowest detachment level mainly in early lactation cows (P < 0.05). However, no significant effect of the detachment level on milking time was observed at milking intervals >10 h. Average milk flow was higher at milking intervals >10 h than ≤10 h (P < 0.05). In the early lactation cows (only) the average milk flow increased with higher detachment levels (P < 0.05). Teat condition did not differ among detachment settings or milking intervals. In conclusion, teat cup detachment up to 125 g/min reduces milking time in both early and late lactation without a loss of milk yield or affecting the teat condition. Combined with a higher average milk flow through avoiding too short milking intervals, the total milking time and hence stall occupancy can be optimized by early teat cup detachment.

Influences on nurses' engagement in antimicrobial stewardship behaviours: A multi-country survey using the Theoretical Domains Framework

BACKGROUND

Antimicrobial resistance (AMR) is significantly affected by inappropriate antibiotic use, and is one of the greatest threats to human health. Antimicrobial stewardship (AMS) is a programme of actions promoting responsible antimicrobial use, and is essential for limiting AMR. Nurses have an important role to play in this context.

AIM

This study investigated the determinants of nurse AMS behaviours and the impact of past training.

METHOD

A cross-sectional multi-country survey design with mixed methods was employed. Participants were 262 nurses (223 female; mean age = 44.45; SD = 10.77 years) from ten nationalities, with individual survey links sent via professional networks in 5 countries, alongside Twitter. Nine AMS behaviours and 14 behavioural determinants were quantitatively assessed using the Theoretical Domains Framework (TDF), and mapped to the COM-B (Capability, Opportunity, Motivation - Behaviour) model. Analysis identified differences between nurses with and without AMS training. The influence of COVID-19 on AMS behaviour was qualitatively investigated using free text data.

FINDINGS

Nurses performed all nine AMS behaviours, which were significantly higher (t(238) = -4.14, p < .001), by those who had training (M = 53.15; SD = 7.40) compared to those who had not (M = 48.30; SD = 10.75). Those with AMS training scored significantly higher in all of the TDF domains. The TDF was able to explain 27% of the variance in behaviour, with 'Skills' and 'Behavioural Regulation' (e.g. ability to self-monitor and plan), shown to be the most predictive of AMS actions. Both of these domains are situated in the Capability construct of COM-B, which can be enhanced with the intervention strategies of education and training. An increase in AMS behaviours was reported since COVID-19, regardless of previous training. Six core themes were linked to AMS: 1) Infection prevention and control, 2) Antimicrobials and antimicrobial resistance, 3) The diagnosis of infection and the use of antibiotics, 4) Antimicrobial prescribing practice, 5) Person-centred care, and 6) Interprofessional collaborative practice.

CONCLUSION

This research, has identified the significant benefit of nurse training on AMS behaviour, and its determinants. Those who had training, scored higher in all TDF determinants of behaviour, compared to those who had had no training, resulting in higher Capability, Opportunity and Motivation to perform AMS behaviours. AMS education and training should be offered to nurses to enhance these factors. Future research should consider the optimal level of training to optimise AMS behaviour, with a focus on developing skills and behavioural regulation.

Effects of acetazolamide on pulmonary artery pressure and prevention of high altitude pulmonary edema after rapid active ascent to 4,559 m

Acetazolamide prevents acute mountain sickness (AMS) by inhibition of carbonic anhydrase. Since it reduces acute hypoxic pulmonary vasoconstriction (HPV), it may also prevent high-altitude pulmonary edema (HAPE) by lowering pulmonary artery pressure. We tested this hypothesis in a randomized, placebo-controlled, double-blind study. Thirteen healthy, non-acclimatized lowlanders with a history of HAPE ascended (<22h) from 1,130 to 4,559m with one overnight stay at 3,611m. Medications started 48h before ascent (acetazolamide: n=7, 250mg 3x/d; placebo: n=6, 3x/d). HAPE was diagnosed by chest radiography, and pulmonary artery pressure by measurement of right ventricular to atrial pressure gradient (RVPG) by transthoracic echocardiography. AMS was evaluated with the Lake Louise Score (LLS) and AMS-C Score. Incidence of HAPE was 43% vs. 67% (acetazolamide vs. placebo, p=0.39). Ascent to altitude increased RVPG from 20±5 to 43±10mmHg (p<0.001) without a group difference (p=0.68). Arterial PO₂ fell to 36±9mmHg (p<0.001) and was 8.5mmHg higher with acetazolamide at high altitude (p=0.025). At high altitude, the LLS and AMS-C score remained lower in those taking acetazolamide (both p<0.05). Although acetazolamide reduced HAPE incidence by 35%, this effect was not statistically significant, and considerably less than reductions of about 70-100% with prophylactic dexamethasone, tadalafil, and nifedipine performed with the same ascent profile at the same location. We could not demonstrate a reduction in RVPG compared to placebo treatment despite reductions in AMS severity and better arterial oxygenation. Limited by a small sample size, our data do not support recommending acetazolamide for prevention of HAPE in mountaineers ascending rapidly to over 4,500m.

Partitioning of Organonitrates in the Production of Secondary Organic Aerosols from α-Pinene Photo-Oxidation

The chemical pathways for the production of secondary organic aerosols (SOA) are influenced by the concentration of nitrogen oxides (NO_x), including the production of organonitrates (ON). Herein, a series of experiments conducted in an environmental chamber investigated the production and partitioning of total organonitrates from α-pinene photo-oxidation from <1 to 24 ppb NO_x. Gas-phase and particle-phase organonitrates (gON and pON, respectively) were measured by laser-induced fluorescence (LIF). The composition of the particle phase and the particle mass concentration were simultaneously characterized by online aerosol mass spectrometry. The LIF and MS measurements of pON concentrations had a Pearson correlation coefficient of 0.91 from 0.3 to 1.1 μg m^-3. For 1-6 ppb NO_x, the yield of SOA particle mass concentration increased from 0.02 to 0.044 with NO_x concentration. For >6 ppb NO_x, the yield steadily dropped, reaching 0.034 at 24 ppb NO_x. By comparison, the yield of pON steadily increased from 0.002 to 0.022 across the range of investigated NO_x concentrations. The yield of gON likewise increased from 0.005 to 0.148. The gas-to-particle partitioning ratio (pON/(pON + gON)) depended strongly on the NO_x concentration, changing from 0.27 to 0.13 as the NO_x increased from <1 to 24 ppb. In the atmosphere, there is typically a cross-over point between clean and polluted conditions that strongly affects SOA production, and the results herein quantitatively identify 6 ppb NO_x as that point for α-pinene photo-oxidation under these study conditions, including the production and partitioning of organonitrates. The trends in SOA yield and partitioning ratio as a function of NOx occur because of the changes in pON volatility.

Rape, sunflower and forest honeys for long-term environmental monitoring: Presence of indicator elements and non-photosynthetic carbon in old Hungarian samples

In this paper, we present the time-dependent elemental composition and AMS radiocarbon dating results of 36 rape, sunflower and forest honey samples, collected between 1985 and 2018 in geographically close locations. Based on the elemental information, we conclude that bee products regardless the type provide useful environmental information of the previous decades, such as the decreasing trend of airborne Pb emission can be traced. However, radiocarbon results agree less with the atmospheric bomb peak. Random offsets were observed in the specific radiocarbon activity of the honey samples indicating that rape, sunflower and forest honey samples are not as reliable materials for radiocarbon dating as acacia honeys. The radiocarbon results show that the rape, sunflower and forest honey samples can contain non-photosynthetic carbon, presumably derived from the soil. Thus, the complex application of honey samples for environmental reconstruction requires the species-separated investigation of bee products to reveal their adaptability for assessment approaches.

Cost-utility analysis of antimicrobial stewardship programme at a tertiary teaching hospital in Ethiopia

OBJECTIVE

Antimicrobial stewardship (AMS) significantly reduces inappropriate antibiotic use and improves patient outcomes. In low-resource settings, AMS implementation may require concurrent strengthening of clinical microbiology capacity therefore additional investments. We assessed the cost-effectiveness of implementing AMS at Tikur Anbessa Specialised Hospital (TASH), a tertiary care hospital in Ethiopia.

DESIGN

We developed a Markov cohort model to assess the cost-utility of pharmacist-led AMS with concurrent strengthening of laboratory capacity compared with usual care from a 'restricted societal' perspective. We used a lifetime time horizon and discounted health outcomes and cost at 3% annually. Data were extracted from a prospective study of bloodstream infections among patients hospitalised at TASH, supplemented by published literature. We assessed parameter uncertainty using deterministic and probabilistic sensitivity analyses.

SETTING

Tertiary care hospital in Ethiopia, with 800 beds and serves over half a million patients per year.

POPULATION

Cohort of adults and children inpatient population aged 19.8 years at baseline.

INTERVENTION

Laboratory-supported pharmacist-led AMS compared with usual care. Usual care is defined as empirical initiation of antibiotic therapy in the absence of strong laboratory and AMS.

OUTCOME MEASURES

Expected life-years, quality-adjusted life-years (QALYs), costs (US$2018) and incremental cost-effectiveness ratio.

RESULTS

Laboratory-supported AMS strategy dominated usual care, that is, AMS was associated with an expected incremental gain of 38.8 QALYs at lower expected cost (incremental cost savings:US$82 370) per 1000 patients compared with usual care. Findings were sensitive to medication cost, infection-associated mortality and AMS-associated mortality reduction. Probabilistic sensitivity analysis demonstrated that AMS programme was likely to be cost-effective at 100% of the simulation compared with usual care at 1%-51% of gross domestic product/capita.

CONCLUSION

Our study indicates that laboratory-supported pharmacist-led AMS can result in improved health outcomes and substantial healthcare cost savings, demonstrating its economic advantage in a tertiary care hospital despite greater upfront investments in a low-resource setting.

Comparative Assessment of Cooking Emission Contributions to Urban Organic Aerosol Using Online Molecular Tracers and Aerosol Mass Spectrometry Measurements

Cooking organic aerosol (COA) is an important source of particulate pollutants in urbanized regions. Yet, the diversity and complexity of COA components make direct identification and quantification of COA difficult. In this study, we conducted collocated OA measurements with an aerosol mass spectrometer (AMS) and a thermal desorption aerosol gas chromatography-mass spectrometer (TAG) in Shanghai. Cooking molecular tracers (e.g., C18 fatty acids, azelaic acid) measured by TAG provide unambiguous source information for evaluating the tracer ion (C₆H₁₀O⁺, m/z 98) used for identification and apportionment of COA in AMS analysis. Based on the collocated AMS and TAG measurements, two COA factors, namely, a primary COA (PCOA) and an oxygenated COA (OCOA) produced from rapid oxygenation of freshly emitted PCOA, were identified. Criteria for identifying COA factors from AMS analysis with different oxygenation levels are proposed, i.e., characteristic mass spectra, temporal variations, etc. Furthermore, two positive matrix factorization approaches, namely, AMS-PMF and the molecular marker (MM)-PMF, were compared for COA quantification, where high consistency was found with the contribution of COA to total PM_2.5 mass estimated to be 9 ± 7% by AMS-PMF and 6 ± 5% by the MM-PMF. Our study highlights the important impacts of cooking activities on air quality in urban areas. We also demonstrate the advantage of conducting collocated measurements using multiple high time resolution mass spectrometric techniques in advancing our understanding of atmospheric OA chemistry and improving the accuracy of source apportionment.

Altered Mental Status: An Important but Overlooked Presenting Symptom of COVID-19 in Older Adults

OBJECTIVES

To determine whether altered mental status (AMS) as a presenting symptom in older adults with COVID-19 is independently associated with adverse outcomes.

METHODS

A retrospective single center observational study of admitted patients (n = 421) age greater than 60 and a positive COVID-19 test. Outcomes included mortality, intubation, acute respiratory distress syndrome, acute kidney injury, and acute cardiac injury. Multivariate regression analysis was used to determine if presenting with AMS was associated with adverse outcomes.

RESULTS

There was an increased risk of mortality (RR 1.29, 95% CI 1.05-1.57), intubation (RR 1.52, 95% CI 1.09-2.12) and AKI (RR 1.42, 95% CI 1.13-1.78) in patients that presented with AMS.

CONCLUSIONS

During a global pandemic, prognostic indicators are vital to help guide the clinical course of patients, reduce healthcare cost, and preserve life. Our study suggests that AMS can play a major role in diagnostic algorithms in older adults with COVID-19.

Production rate variation and changes in sedimentation rate of marine core dated with meteoric 10Be and 14C

The first measurement of meteoric beryllium-10 (¹⁰Be) using Accelerator Mass Spectrometer (AMS) is reported from PRL-AURiS (Physical Research Laboratory-Accelerator Unit for Radioisotope Studies). Strategically, the meteoric ¹⁰Be dating method can date events as old as 10 Myr, and its accuracy while dating marine sediment cores has been well tested with magnetic methods. An attempt is made for a comparative study between radiocarbon (¹⁴C) and meteoric ¹⁰Be dating methods from a 6 m long sediment core collected from the equatorial Indian Ocean. The core was dated using both radiocarbon and meteoric ¹⁰Be and results showed remarkable similarity for both methods in terms of the sedimentation rate. A continuous age offset observed within 50 kyr could be due to a continuous influx of sediment with low ¹⁰Be content and that may have caused the meteoric ¹⁰Be ages to be younger. The sedimentation rate calculated by changing the ¹⁰Be depositional flux rate from 1.5 to 2.5 × 10^-2 atoms.cm^-2.s^-1 shows large variation, indicating the choice of appropriate ¹⁰Be depositional flux rate for the region. Additionally, being the first meteoric beryllium-10 measurements using AURiS, we have also discussed and reported the laboratory protocols and efficiency based on repeat standard and blank measurements.

A record of fallout 239Pu and 240Pu at World Heritage Bathurst Harbour, Tasmania, Australia

This study presents the first measurements of anthropogenic plutonium (²³⁹Pu and ²⁴⁰Pu) concentrations and atom ratios (²⁴⁰Pu/²³⁹Pu) for Tasmania, in sediment collected from Bathurst Harbour, in the Tasmanian Wilderness World Heritage Area, Australia. The weighted mean ²⁴⁰Pu/²³⁹Pu atom ratio measured at this site was 0.172 ± 0.007 which is consistent with published data from mainland Australia and global and Southern Hemisphere averages. The ²⁴⁰Pu/²³⁹Pu atom ratios ranged between 0.11 and 0.21 with the earliest recorded ²⁴⁰Pu/²³⁹Pu atom ratios being the lowest, suggesting an influence of low atom ratio fallout from nuclear testing in Australia. Post-moratorium fallout ²⁴⁰Pu/²³⁹Pu atom ratios were consistent with other records. Lead-210 (²¹⁰Pb) sediment chronologies indicate sediment accumulation rates have increased since the early part of the 19th century at this location.

Which is the best 9Be carrier for 10Be/9Be accelerator mass spectrometry?

Commercial ⁹Be solutions used for chemical preparation of samples for accelerator mass spectrometry contain the cosmogenic long-lived radionuclide ¹⁰Be at elevated but different ¹⁰Be/⁹Be levels. Within a systematic study of recently produced solutions, comparison to published data and new data on customised solutions from minerals, we recommend - if no customised solution is available - the ⁹Be solutions from Australian Chemical Reagents (ACR) or from LGC. They contain ¹⁰Be/⁹Be at the 3.4 × 10⁻¹⁵ level, which is still suitable for the majority of Earth science applications, compared to customised solutions at the 10⁻¹⁶ level for lowest-level studies. Commercial solutions from Scharlab having different lot numbers, i.e. an identification number assigned to a particular lot of material from a single manufacturer, vary in ¹⁰Be/⁹Be by up to a factor of nine. Hence, it seems an advisable strategy to buy a bigger quantity of a single production batch (such as 10 × 100 ml bottles of ⁹Be at 1 g l⁻¹) and have them tested once at any AMS facility before first use.•

The best ⁹Be carrier for low-level ¹⁰Be/⁹Be applications is a customised one from minerals like phenakite.

•

The best ⁹Be carriers for medium- and high-level ¹⁰Be/⁹Be applications are currently from Australian Chemical Reagents (ACR) or from LGC.

•

As ⁹Be carriers from Scharlab of different batches (LOT) contain ¹⁰Be/⁹Be at different levels, it is advisable to buy a bigger number of bottles of the same LOT of commercial carriers after being identified to have reasonably low isotope ratios.

Determination of minor isotope ratios of individual uranium particles by accelerator mass spectrometry

The determination of uranium isotope ratios in uranium particle is an essential technique in the analysis of environmental samples for nuclear safeguards. At present, mass spectrometry has been widely used to measure isotope ratios of uranium particles. We developed a new analytical method for measuring minor isotope ratios of individual uranium particles directly. The technique includes single particle identification by energy dispersive X-ray spectrometer (EDX), transfer by scanning electron microscope (SEM) combined with micromanipulator and isotope ratios analysis with accelerator mass spectrometry (AMS). The minor isotope ratios of individual uranium particles with four isotopic abundances and different sizes from certified reference materials were measured by AMS. The results show that the relative error (RE, i.e., the deviation of measured value from the certified value) of ²³⁴ U/²³⁵ U and ²³⁴ U/²³⁶ U isotope ratios was 9.0% and 19.3%, respectively, and the relative standard deviation (RSD) was within 9.9% and 16%, respectively. The minimum particle determined was about 2 μm. The method was found to be an alternative analytical means for nuclear safeguards.

236U, 237Np and 239,240Pu as complementary fingerprints of radioactiveeffluents in the western Mediterranean Sea and in the Canada Basin (Arctic Ocean)

The aim of this study was to assess the potential of combining the conservatively behaving anthropogenic radionuclides ²³⁶U and ²³⁷Np to gain information on the origin of water masses tagged with liquid effluents from Nuclear Reprocessing Plants. This work includes samples collected from three full-depth water columns in two areas: i) the Arctic Ocean, where Atlantic waters carry the signal of Sellafield (United Kingdom) and La Hague (France) nuclear reprocessing facilities; and ii) the western Mediterranean Sea, directly impacted by Marcoule reprocessing plant (France). This work is complemented by the study of the particle-reactive Pu isotopes as an additional fingerprint of the source region. In the Canada Basin, Atlantic waters showed the highest concentrations and ²³⁷Np/²³⁶U ratios in agreement with the estimated values for North Atlantic waters entering the Arctic Ocean and tagged with the signal of European Nuclear Reprocessing Plants. These results may reflect the impact of the documented releases for the 1990s. In the Mediterranean Sea, an excess of ²³⁶U presumably caused by Marcoule is reflected in the lower ²³⁷Np/²³⁶U ratios compared to the Global Fallout signal in all the studied samples. On the contrary, the ^239,240Pu profiles were mainly governed by the Global Fallout. The impact of Marcoule as a local source is further corroborated when comparing the temporal evolution of these ratios between 2001 and 2013. The lowest ²³⁷Np/²³⁶U ratios observed in 2001 at the surface reflect a previous local input that is no longer observed in 2013 as it had been homogenized through the whole water column. This work presents the use of ²³⁷Np as a new ocean tracer. A more accurate characterization of the main sources is still needed to optimize the use of ²³⁶U-²³⁷Np as a new tool to understand transient oceanographic processes.

Rapid and efficient autoclave digestion for the extraction of iodine-129 from urine samples

A new method was developed to extract ¹²⁹I from urine samples and measure it using accelerator mass spectrometry (AMS). The samples were pre-treated in an autoclave with hydrogen peroxide and were then acidified with nitric acid, followed by the precipitation of iodine as silver iodide (AgI) for measurement by AMS. This new procedure is substantially faster than previous methods for the extraction of iodine from urine and results in less chemical waste. The efficiency and reproducibility of this method were evaluated by using ¹²⁵I as a yield tracer, eventually giving a recovery above 99%. To achieve this, several iterations of the method were required. The method was then successfully applied to measure ¹²⁹I/¹²⁷I isotopic ratios and ¹²⁹I concentrations in 25 human urine samples. The AMS results for ¹²⁹I in urine ranged 3.3 × 10⁶ atoms/L to 884 × 10⁶ atoms/L and the isotope ratio (¹²⁹I/¹²⁷I) in human urine ranged from 7.38 × 10^-12 to 3.97 × 10^-10 with a median of 1.29 × 10^-10. This new method will be useful for investigations into the sources of iodine in the human diet and their relative importance for iodine sufficiency.

Hand Motion Capture from a 3D Leap Motion Controller for a Musculoskeletal Dynamic Simulation

The AnyBody Modeling System™ (AMS) is a musculoskeletal software simulation solution using inverse dynamics analysis. It enables the determination of muscle and joint forces for a given bodily motion. The recording of the individual movement and the transfer into the AMS is a complex and protracted process. Researches indicated that the contactless, visual Leap Motion Controller (LMC) provides clinically meaningful motion data for hand tracking. Therefore, the aim of this study was to integrate the LMC hand motion data into the AMS in order to improve the process of recording a hand movement. A Python-based interface between the LMC and the AMS, termed ROSE Motion, was developed. This solution records and saves the data of the movement as Biovision Hierarchy (BVH) data and AnyScript vector files that are imported into the AMS simulation. Setting simulation parameters, initiating the calculation automatically, and fetching results is implemented by using the AnyPyTools library from AnyBody. The proposed tool offers a rapid and easy-to-use recording solution for elbow, hand, and finger movements. Features include animation, cutting/editing, exporting the motion, and remote controlling the AMS for the analysis and presentation of musculoskeletal simulation results. Comparing the motion tracking results with previous studies, covering problems when using the LMC limit the correctness of the motion data. However, fast experimental setup and intuitive and rapid motion data editing strengthen the use of marker less systems as the herein presented compared to marker based motion capturing.

High-altitude Illnesses and Air Travel: Pediatric Considerations

Healthy children may present acute mountain sickness (AMS) within a few hours after arrival at high altitudes. In few cases, serious complications may occur, including high-altitude pulmonary edema and rarely high-altitude cerebral edema. Those with preexisting conditions especially involving hypoxia and pulmonary hypertension shall not risk travelling to high altitudes. Newborn from low altitude mothers may have prolonged time to complete postnatal adaptation. The number of children and adolescents traveling on commercial aircrafts is growing, and this poses a need for their treating physicians to be aware of the potential risks of hypoxia while air traveling.

Assessing the Impact of COVID-19 on Antimicrobial Stewardship Activities/Programs in the United Kingdom

Since first identified in late 2019, the acute respiratory syndrome coronavirus (SARS-CoV2) and the resulting coronavirus disease (COVID-19) pandemic has overwhelmed healthcare systems worldwide, often diverting key resources in a bid to meet unprecedented challenges. To measure its impact on national antimicrobial stewardship (AMS) activities, a questionnaire was designed and disseminated to antimicrobialstewardship leads in the United Kingdom (UK). Most respondents reported a reduction in AMS activity with 64% (61/95) reporting that COVID-19 had a negative impact on routine AMS activities. Activities reported to have been negatively affected by the pandemic include audit, quality improvement initiatives, education, AMS meetings, and multidisciplinary working including ward rounds. However, positive outcomes were also identified, with technology being increasingly used as a tool to facilitate stewardship e.g., virtual meetings and ward rounds and increased the acceptance of using procalcitonin tests to distinguish between viral and bacterial infections. The COVID-19 pandemic has had a significant impact on the AMS activities undertaken across the UK. The long-term impact of the reduced AMS activities on incidence of AMR are not yet known. The legacy of innovation, use of technology, and increased collaboration from the pandemic could strengthen AMS in the post-pandemic era and presents opportunities for further development of AMS.

Antimicrobial Stewardship: Development and Pilot of an Organisational Peer-to-Peer Review Tool to Improve Service Provision in Line with National Guidance

Antimicrobial resistance continues to be a considerable threat to global public health due to the persistent inappropriate use of antibiotics. Antimicrobial stewardship (AMS) programs are essential in reducing the growth and spread of antibiotic resistance, in an environment which lacks incentives for the development of new antibiotics. Over the years, a variety of resources have been developed to strengthen antimicrobial stewardship. However, the differences in resources available present a challenge for organisations/teams to establish the best resources to utilise for service provision. A peer review tool was formulated using four national documents on AMS and tested through three phases with feedback. A survey method was used to collect feedback on the validity, feasibility, and impact of the AMS peer review tool. Feedback received was positive from the earlier pilots. The tool was found to be useful at identifying areas of good practice and gaps in antimicrobial stewardship across various pilot sites. Feedback suggests the tool is useful for promoting improvements to AMS programs and highlights that the content and features of the tool are appropriate for evaluating stewardship.

Relative contributions of selected multigeneration products to chamber SOA formed from photooxidation of a range (C10-C17) of n-alkanes under high NO x conditions

A series of chamber experiments was conducted to investigate the composition of secondary organic aerosol (SOA) following oxidation of a range of parent n-alkanes (C10-C17) in the presence of NO x . The relative contribution of selected species representing first, second, and higher generation products to SOA mass was measured using a high-resolution aerosol mass spectrometer. Gas chromatography was also used for a limited set of amenable species. Relative contributions varied substantially across the range of investigated alkanes reflecting slight changes in SOA composition. The contribution of first-generation cyclic hemiacetal is minimal toward the small end of the investigated range and gradually increase with n-alkane size. The relative contribution of second generation and higher nitrate-containing species, in contrast, decrease with an increased alkane size. A similar trend is observed for relative contribution of organonitrates to SOA. Finally, SOA yield and composition are sensitive to water vapor concentrations. This sensitivity is limited to a narrow range (dry to ~15% RH) with little, if any, impact above 15% suggesting that this impact may be negligible under ambient conditions. The impact of water vapor also appears to decrease with increasing alkane carbon number.

Insights into the Pu isotopic composition (239Pu, 240Pu, and 241Pu) and 236U in marshland samples from Madagascar

This work provides new insights into the presence of ²³⁹Pu, ²⁴⁰Pu, ²⁴¹Pu, and ²³⁶U in the Southern Hemisphere through the study of peat bog cores from marshlands in Madagascar (19°S). ²¹⁰Pb, ²³⁸Pu and ^239+240Pu activities were characterized by alpha spectrometry in previous studies. Here, Pu from alpha-spectrometry discs corresponding to 10 peat-bog cores (85 samples) was reassessed for the aim of completing its isotopic composition (²³⁹Pu, ²⁴⁰Pu, and ²⁴¹Pu) by Accelerator Mass Spectrometry. In addition, ²³⁶U was studied in a single core exhibiting unusually low ²⁴⁰Pu/²³⁹Pu ratios. Integrated ²⁴⁰Pu/²³⁹Pu atom ratios in the single cores ranged above and below the (0-30°S) fallout average ratio, 0.173 ± 0.027, from 0.126 ± 0.003 to 0.206 ± 0.002, without a regional pattern, thereby demonstrating the heterogeneous distribution of the ²³⁹Pu and ²⁴⁰Pu signal. However, such a variability was not observed for ²⁴¹Pu/²³⁹Pu, ranging from (6 ± 1) · 10^-4 to (11 ± 1) · 10^-4 and consistently below the (0-30°S) fallout ratio of (9.7 ± 0.3) · 10^-4 (2012). The integrated ²³⁶U/²³⁹Pu atom ratio in the studied core, 0.147 ± 0.005, was also significantly lower than the values reported for the global fallout in the Northern Hemisphere, in the 0.20-0.23 range. Our results point out to stratospheric fallout as the main source of both ²³⁶U and ²⁴¹Pu at the studied site, whereas ²³⁹Pu and ²⁴⁰Pu signals show the influence of tropospheric fallout from the low-yield tests conducted in Australia (1952-1958) by United Kingdom and in French Polynesia (1966-1975) by France despite the long relative distances (i.e. about 15,000 and 8500 km). It was also demonstrated that a representative number of samples is necessary in order to assess Pu contamination and its various origins in a specific region in the Southern Hemisphere due to the heterogeneous distribution, and results based on single sample analysis should be interpreted with caution.

Clinical worsening due to inappropriate automatic mode switch during biventricular pacing: What is the mechanism?

We describe a case of a 65-year-old gentleman with nonischemic cardiomyopathy and left bundle branch block who underwent cardiac resynchronization therapy device. After becoming a responder initially, he experienced significant clinical worsening on follow-up. Device interrogation revealed several long episodes of inappropriate automatic mode switch (AMS) entry due to far-field R wave oversensing resulting in loss of atrioventricular synchrony. Moreover, pacing in VVI mode with consistent VA conduction taking place during the AMS episodes was also found to be detrimental, which helped in sustaining the episodes and produced pacemaker syndrome like phenomenon. Attempts made to resolve the issue by prolonging the post-ventricular atrial blanking period was unsuccessful, hence we adjusted the atrial channel sensitivity to troubleshoot the problem.

Rapid ascents of Mt Everest: normobaric hypoxic preacclimatization

BACKGROUND

Acclimatization to high altitude is time consuming. An expedition to Mt Everest (8848 m) requires roughly 8 weeks. Therefore it seems very attractive to reach the summit within 3 weeks from home, which is currently promised by some expedition tour operators. These rapid ascent expeditions are based on two main components, normobaric hypoxic training (NHT) prior to the expedition and the use of high flow supplemental oxygen (HFSO2). We attempted to assess the relative importance of these two elements.

METHODS

We evaluated the effect of NHT on the basis of the available information of these rapid ascent expeditions and our experiences made during an expedition to Manaslu (8163 m) where we used NHT for preacclimatization. To evaluate the effect of an increased O2 flow rate we calculated its effect at various activity levels at altitudes of 8000 m and above.

RESULTS

So far rapid ascents to Mt Everest have been successful. The participants carried out 8 weeks of NHT, reaching sleeping altitudes = 7100 m and spent at least 300 h in NH. At rest a flow rate of 2 l O2/min is sufficient to keep the partial pressure of inspired oxygen (PIO2) close to 50 mm Hg even at the summit. For ativities of ~80% of the maximum rate of oxygen consumption (VO2max) at the summit 6 l O2/min are required to maintain a PIO2 above 50 mm Hg.

DISCUSSION

NHT for preacclimatization seems to be the decisive element of the offered rapid ascent expeditions. An increased O2 flow rate of 8 l/min is not mandatory for climbing Mt Everest.

CONCLUSIONS

Preacclimatization using normobaric hypoxica (NH) is far more important than the use of HFSO2. We think that NHT will be widely used in the future. The most effective regimen of preacclimatization in NH, the duration of each session and the optimal FIO2 are still unclear and require further study.

Honey as an indicator of long-term environmental changes: MP-AES analysis coupled with 14C-based age determination of Hungarian honey samples

Several studies show that the elemental content of honey entirely depends on the botanical and geographical origin, but the information is incomplete regarding its time-dependent composition changes. Twenty-six acacia and three honey samples with unknown botanical origin were collected between 1958 and 2018 and analysed for elemental composition by Microwave Plasma Atomic Emission Spectrometry (MP-AES). The elemental analysis was coupled with independent dating method by Accelerator Mass Spectrometry (AMS) to confirm the calendar age of the honey samples and test the possibility of radiocarbon based dating of bee products, which has not been applied before. According to the analytical measurements and statistical analysis, we can conclude that the elemental composition shows change with time in the acacia honey during the last five decades. We have proven that honey preserves carbon isotopic and elemental information of its production time and thus can be applied as an environmental indicator (e.g. trace urban pollutants, precipitation, local industrial or agricultural emission) in reconstruction studies by analysing the non-degradable mineral content. Our results further show that acacia honey is a suitable material for radiocarbon dating, proved by the results compared to the atmospheric radiocarbon bomb-peak. The new approach presented for investigation of honey by radiocarbon-based age determination coupled with elemental analysis can be used in biological, dietary, archaeological or other multidisciplinary studies as well. Some samples show slightly depleted radiocarbon content. This could be an indication of local fossil CO₂ emission. Based on these depleted ¹⁴C results, honey could be used for atmospheric monitoring of fossil CO₂ urban or industrial hot-spots.

Challenges in Implementing Antimicrobial Stewardship Programmes at Secondary Level Hospitals in India: An Exploratory Study

Introduction: Implementing a sustainable and effective Antimicrobial Stewardship (AMS) programme in secondary level hospitals, in Low-Middle Income Country (LMIC) contexts, has numerous challenges. It is important to understand these challenges so that the stewardship initiatives can be tailored according to the unique requirements thrown up by these healthcare facilities. This study explores the experiences of implementing AMS in secondary level hospitals in the state of Kerala, India.

Methods: A qualitative study was planned to map the challenges in implementing AMS in the secondary level hospitals. Toward the end of the 1 year followup period, the nodal officers at each hospital were interviewed using a semi-structured interview guide. The in-depth interviews were transcribed and later subjected to content analysis using N-Vivo 11.0, a popular software tool used for qualitative analysis.

Results: Many physicians cite perceived patient satisfaction as one of the reasons for increased antibiotic use, as many patients consider antibiotics as standard of care. Also, the distance traveled by the patient and advancing age are factors which increase antibiotic use. The physician factors which determine use include empiric treatment needs, outbreak of diseases, absence of education programmes in antibiotic usage to fill in the knowledge gap and fear of litigation. The promotional activities by companies and antibiotics being a major source of income for small hospitals, affects use patterns. The factors which determine antibiotic selection includes conformism, experience of the physician, perceived resistance to certain antibiotics, emergence of specific diseases, and promotional activities related to antimicrobial agents. The challenges in implementing a sustainable stewardship programme is multifactorial. It includes competition between doctors, time constraints faced by physicians, absence of a champion, sub-optimal interdepartmental cooperation, absence of supporting facilities, dysfunctional regulatory systems, and unreliability of antibiograms.

Discussion: AMS in resource-limited setting is going to be a challenge, especially in terms of financing, access to technologies and capacity building. Political and regulatory willpower of international partnerships should be effectively harnessed for designing solutions for LMIC contexts. Also, models for stewardship from elsewhere should undergo an adaptation process before implementation in low resource settings.

Heterogeneous approach to nebulization of antimicrobial agents in mechanically ventilated adults in a German tertiary care hospital: a cross-sectional survey

There is lack of standardization of practices and limited evidence on efficacy and safety of nebulization of antimicrobials. We sought to determine inhalation practices in one tertiary care hospital by performing a cross-sectional survey. Eleven adult ICUs were included in the analysis. Three units followed established protocols. Ventilation circuit filters were exchanged at least daily in all but one units. Dosages of aminoglycosides and CMS depended on indication and unit. Nebulization of antimicrobials was generally regarded as safe and efficacious. Our data indicate that approach to nebulization of antimicrobials may be heterogeneous even in a single center.

Reactivity of allyl methyl sulphide, the in-vitro metabolite of garlic, with some amino acids and with phospholipid involved in viral infections

Garlic, as well as several natural food ingredients such as basil, ginger, turmeric, cinnamon, clove, pepper etc., has long been traditionally used as routine anti-viral and anti-bacterial remedy. Allyl methyl sulfide (AMS) is reportedly a persistent main active metabolite component of allicin after garlic ingestion accounting for at least 90% of the allicin consumed. Several studies have reported the presence of AMS in organs such as lung, kidney etc. and body fluids such as mucous, and blood-plasma. Glycoproteins of enveloped viruses are actively involved in viral pathogenesis. N-acetylneuraminic acid (sialic acid) and N-Acetylglucosamine, are some of the vital amino acids involved in several viral infections using glycoproteins via glycosylation. Simulations studies based on First-principles density functional theory show that these amino acids attach with AMS, and the reactions are thermodynamically spontaneous (ΔG and ΔS negative are at 310.15 K as well as lower and higher temperatures). Further, phospholipid phosphatidylethanolamine (a component of some viral envelops) also attaches readily with AMS and the reaction is spontaneous. AMS molecules attachment with viral phospholipids and amino-acids involved in viral infection would denature the virus and prevent its attachment to the host cell.Communicated by Ramaswamy H. Sarma.

The effects of humidity and ammonia on the chemical composition of secondary aerosols from toluene/NOx photo-oxidation

The secondary aerosol formation mechanism in the presence of ammonia (NH₃), is poorly understood, especially under high relative humidity (RH) conditions. In this study, a total of seven experiments were conducted from toluene/NOx photo-oxidation in the presence/absence of NH₃ under dry (~7% RH) and wet (>60% RH) conditions in a ~3 m³ smog chamber. A series of instruments including gas analysers, scanning mobility particle sizer (SMPS), aerosol mass spectrometry (HR-ToF-AMS) etc. were applied to measure the NOx and O₃ concentrations, the mass concentration and chemical composition of secondary aerosol. It was found that NH₃ could enhance the mass loading of secondary aerosol, especially under wet condition. However, the presence of NH₃ or increasing RH did not have a significant influence on SOA yield. The organic aerosol mass spectrum from AMS showed that the most abundant fragment was at m/z = 44, which was mainly from the fragmentation of carboxylic acids. Compared to the absence of NH₃, the fraction of fragment at m/z = 44 and O:C was higher in the presence of NH₃, regardless of dry or wet conditions. The highest O:C value of 0.71-0.75 was observed in the presence of NH₃ under wet condition, suggesting there could be a synergetic effect between the high RH and the presence of NH₃, which jointly contributed to the photochemical aging process of SOA. The N:C increased in the presence of NH₃ under both dry and wet conditions, which might be attributed to the carboxylates and organic nitrates formed from the reaction between NH₃ and carboxylic acids. The results implied that SOA modelling should consider the role of NH₃ and water vapour, which might fill the gap of O:C between laboratory studies and field measurements.

Iodine-129 for determining the origin of salinity in groundwater in Pampanga, Philippines

Assessing groundwater vulnerability from salinity contamination is vital and relevant to meet the increasing demand for freshwater. Iodine-129 (¹²⁹I, half-life = 15.7 million years), a radioisotope of iodine, was used as an environmental tracer for the possible origin of salinization in groundwater (e.g., natural rock weathering, evaporated water, seawater, brine fossil water, contamination). In July 2017 (wet season), thirty-two (32) water samples were taken from production wells of different localities in Pampanga, a province in the Philippines that relies heavily on groundwater for freshwater sources. Hydrogeochemical (mainly Cl) and stable water isotopes (δ²H and δ¹⁸O) were able to identify seven samples potentially affected by seawater intrusion. The salinity origin of these samples was investigated using iodine-129 and iodine-127 isotopes by generating two graphs: ¹²⁹I vs. chloride and ¹²⁹I/¹²⁷I ratio vs. 1/¹²⁷I. ¹²⁹I vs. Cl graph was capable of showing a clear distinction between different salinity origins. Five out of the seven samples were being affected by evaporated water, one sample from possible wastewater, and one sample from brine fossil water. A conceptual model was produced to summarize the results. Compiled end-members (e.g., natural brine, seawater, modern rain) were plotted in the ¹²⁹I/¹²⁷I ratio vs. 1/¹²⁷I graph to show the interaction between two recharge sources. The results of this study will be helpful to the government, civil society, and other organizations for monitoring, policymaking, and management of the groundwater and the subsurface formations that will be crucial to continuously supply the freshwater needs of the present and future generation.

Radiocarbon analysis of carbonaceous aerosols in Bratislava, Slovakia

Aerosols dispersed in the atmosphere represent important factors influencing not only the environment, but also human health. Carbonaceous aerosols are one of the main components of total atmospheric aerosols, and their sources are of great interest. Radiocarbon analysis provides an excellent way to determine the fraction of fossil and non-fossil aerosols in the atmosphere. Over the period of one year (June 2017-June 2018), we sampled atmospheric aerosols with size greater than 0.3 μm in Bratislava, Slovakia and used the exposed quartz filters for radiocarbon analysis of the elemental carbon (EC) aerosol fraction. The results show that on average the fossil fuel combustion is the dominant source of EC aerosol particles in Bratislava. In summer months, they represent more than half (65-80%) of the total EC aerosols. The relative amount of EC particles derived from biomass burning was 20-35% in summer, which increased to 40-55% in winter months. The dominance of fossil fraction is caused by high degree of industrialization and urbanization of the city. The increase of biomass fraction in winter is probably caused by domestic wood burning in areas surrounding the Bratislava city.

Establishing a pharmacist-prescriber partnership in publicly funded primary healthcare clinics to optimise antibiotic prescribing in the Western Cape: An exploratory study

Background

Promoting evidence-based antibiotic prescribing through successful antimicrobial stewardship (AMS) programmes is critical to preserving the effectiveness of antibiotics for common infections in primary care. This requires a coordinated multidisciplinary effort. Such pharmacist–prescriber partnerships have been effective in high-income countries (HICs). Yet, evidence generated in such countries is not always applicable because of different social determinants of health.

Methods

A multidisciplinary workshop was conducted with pharmacists and clinicians (doctors, nurses) on community-based antibiotic stewardship, the purpose of which was to explore how and where such partnerships might work in publicly funded primary care clinics in the greater Cape Metro region.

Results

Participants perceived that promoting effective AMS was a priority for South African primary healthcare. However, it was clear that there are many hurdles to overcome working in settings that are relatively resource-poor. Prescribing guidelines needed to be harmonised. Participants felt that staff training on the principles of AMS should be mandatory. Research was urgently needed to better understand their community’s understanding of antibiotic use and AMS, and to champion outreach projects in the community.

Conclusion

Important stakeholder perspectives in the community were highlighted to promote a multidisciplinary approach to AMS initiatives in primary care. These will need to be addressed to optimise antibiotic prescribing in the community.