HISTOMONAS MELEAGRIDIS INFECTIONS IN TURKEYS IN THE USA: A CENTURY OF PROGRESS, RESURGENCE, AND TRIBUTE TO ITS EARLY INVESTIGATORS, THEOBALD SMITH, ERNST TYZZER, AND EVERETT LUND.

Histomoniasis, caused by the protozoan, Histomonas meleagridis, is an economically important disease of turkeys, and it also affects several other species of domesticated and wild Galliformes, including chickens. Under natural conditions, the parasite is transmitted through eggs of a nematode, Heterakis gallinarum, that shares its hosts with Hi. meleagridis. The protozoan infects tissues of both male and female He. gallinarum and eventually is carried within the worm egg. Histomonas meleagridis more readily infects and develops in chickens, and the proximity of chicken farms is a major risk factor for outbreaks in turkeys. Chemoprophylaxis had controlled Hi. meleagridis in turkeys very successfully, but histomoniasis has recently reemerged in turkeys because anti-histomonal drugs are no longer permitted by the United States Food and Drug Administration because of the concerns for residual toxins in poultry meat. Horizontal transmission of the protozoan in the absence of worm eggs remains a mystery because the flagellate trophozoite excreted in the feces of turkeys is not viable for any length of time. A proposed resistant stage of the protozoan has not yet been conclusively demonstrated. Here we review the discovery of the protozoan and the current status of the disease and its control.

2-Dimensional Echocardiographic Global Longitudinal Strain With Artificial Intelligence Using Open Data From a UK-Wide Collaborative.

BACKGROUND: Global longitudinal strain (GLS) is reported to be more reproducible and prognostic than ejection fraction. Automated, transparent methods may increase trust and uptake. OBJECTIVES: The authors developed open machine-learning-based GLS methodology and validate it using multiexpert consensus from the Unity UK Echocardiography AI Collaborative. METHODS: We trained a multi-image neural network (Unity-GLS) to identify annulus, apex, and endocardial curve on 6,819 apical 4-, 2-, and 3-chamber images. The external validation dataset comprised those 3 views from 100 echocardiograms. End-systolic and -diastolic frames were each labelled by 11 experts to form consensus tracings and points. They also ordered the echocardiograms by visual grading of longitudinal function. One expert calculated global strain using 2 proprietary packages. RESULTS: The median GLS, averaged across the 11 individual experts, was -16.1 (IQR: -19.3 to -12.5). Using each case's expert consensus measurement as the reference standard, individual expert measurements had a median absolute error of 2.00 GLS units. In comparison, the errors of the machine methods were: Unity-GLS 1.3, proprietary A 2.5, proprietary B 2.2. The correlations with the expert consensus values were for individual experts 0.85, Unity-GLS 0.91, proprietary A 0.73, proprietary B 0.79. Using the multiexpert visual ranking as the reference, individual expert strain measurements found a median rank correlation of 0.72, Unity-GLS 0.77, proprietary A 0.70, and proprietary B 0.74. CONCLUSIONS: Our open-source approach to calculating GLS agrees with experts' consensus as strongly as the individual expert measurements and proprietary machine solutions. The training data, code, and trained networks are freely available online.

Chloroplast NADH dehydrogenase-like complex-mediated cyclic electron flow is the main electron transport route in C4 bundle sheath cells.

The superior productivity of C4 plants is achieved via a metabolic C4 cycle which acts as a CO2 pump across mesophyll and bundle sheath (BS) cells and requires an additional input of energy in the form of ATP. The importance of chloroplast NADH dehydrogenase-like complex (NDH) operating cyclic electron flow (CEF) around Photosystem I (PSI) for C4 photosynthesis has been shown in reverse genetics studies but the contribution of CEF and NDH to cell-level electron fluxes remained unknown. We have created gene-edited Setaria viridis with null ndhO alleles lacking functional NDH and developed methods for quantification of electron flow through NDH in BS and mesophyll cells. We show that CEF accounts for 84% of electrons reducing PSI in BS cells and most of those electrons are delivered through NDH while the contribution of the complex to electron transport in mesophyll cells is minimal. A decreased leaf CO2 assimilation rate and growth of plants lacking NDH cannot be rescued by supplying additional CO2. Our results indicate that NDH-mediated CEF is the primary electron transport route in BS chloroplasts highlighting the essential role of NDH in generating ATP required for CO2 fixation by the C3 cycle in BS cells.

Thermal stressors during embryo incubation have limited ontogenic carryover effects in brook trout.

Winter climate is changing rapidly in northern latitudes, and these temperature events have effects on salmonid thermal biology. Stressors during winter egg incubation could reduce hatching success and physiological performance of fall-spawning fishes. Here we quantified the potential for ontogenic carryover effects from embryonic thermal stress in multiple wild and hatchery-origin populations of brook trout (Salvelinus fontinalis), a temperate ectotherm native to northeastern North America. Fertilized eggs from four populations were incubated over the winter in the laboratory in four differing thermal regimes: ambient stream-fed water, chronic warming (+2 °C), ambient with a mid-winter cold-shock, and short-term warming late during embryogenesis (to stimulate an early spring). We examined body size and upper thermal tolerance at the embryonic, fry (10 weeks post-hatch and 27-30 weeks post-hatch) and gravid adult (age 2+) life stages (overall N = 1482). In a separate experiment, we exposed developing embryos to acute seven-day heat stress events immediately following fertilization and at the eyed-egg stage, and then assessed upper thermal tolerance (CTmax) 37 weeks post-hatch. In all cases, fish were raised in common garden conditions after hatch (i.e., same temperatures). Our thermal treatments during incubation had effects that varied by life stage, with incubation temperature and life stage both affecting body size and thermal tolerance. Embryos incubated in warmer treatment groups had higher thermal tolerance; there was no effect of the mid-winter melt event on embryo CTmax. Ten weeks after hatch, fry from the ambient and cold-shock treatment groups had higher and less variable thermal tolerance than did the warmer treatment groups. At 27-30 post-hatch and beyond, differences in thermal tolerance among treatment groups were negligible. Collectively, our study suggests that brook trout only exhibit short-term carryover effects from thermal stressors during embryo incubation, with no lasting effects on phenotype beyond the first few months after hatch.

Validation of a new acoustic telemetry transmitter for the study of predation events in small fishes.

Acoustic telemetry has emerged as an important tool for studying the movement and behavior of aquatic animals. Predation-sensing acoustic transmitters combine the functions of typical acoustic transmitters with the added ability to identify the predation of tagged animals. The objective of this paper was to assess the performance of a newly miniaturized acid-based predation-sensing acoustic transmitter (Innovasea V3D; 0.33 g in air). We conducted staged predation events in the laboratory where acoustically tagged rainbow trout (Oncorhynchus mykiss) were fed to largemouth bass (Micropterus nigricans) at 3.3-7.0, 9.0-10.8, 16.0-20.0, and 22.0-25.8°C. We also conducted false-positive tests where tagged rainbow trout were held at 10.0 and 16.8°C without the risk of predation. Predation events were successfully identified in 92% of the staged predation trials. Signal lag (i.e., the time required for a predation tag to indicate that predation occurred) ranged from 0.11 to 6.29 days and decreased strongly with increasing water temperature and increased with increasing body mass of the tagged prey. Tag retention in the gut of the predator was much more variable than signal lag and was influenced by water temperature and individual predators but not by prey mass. No false positives were detected after 60 days at either temperature (n = 27 individuals). Although the relationships between water temperature, signal lag, and retention time are likely species-specific, the data reported here provide useful information for the use of these transmitters to study predation in wild fishes, especially for temperate, freshwater fish.

Thermal performance curves for aerobic scope and specific dynamic action in a sexually dimorphic piscivore: implications for a warming climate.

Digestion can make up a substantial proportion of animal energy budgets, yet our understanding of how it varies with sex, body mass, and ration size is limited. A warming climate may have consequences on animal growth and feeding dynamics that will differentially impact individuals in their ability to efficiently acquire and assimilate meals. Many species, such as walleye (Sander vitreus), exhibit sexual size dimorphism (SSD), whereby one sex is larger than the other, suggesting sex-differences in energy acquisition and/or expenditure. Here we present the first thorough estimates of specific dynamic action (SDA) in adult walleye using intermittent-flow respirometry. We fed male (n=14) and female (n=9) walleye two ration sizes; 2% and 4% of individual body weight, over a range of temperatures from 2 - 20°C. SDA was shorter in duration and reached higher peak rates of oxygen consumption with increasing temperatures. Peak SDA increased with ration size and decreased with body mass. The proportion of digestible energy lost to SDA (i.e., the SDA coefficient) was consistent at 6% and was unrelated to temperature, body mass, sex, or ration size. Our findings suggest that sex has a negligible role in shaping SDA, nor is SDA a contributor to SSD for this species. Standard and maximum metabolic rates were similar between sexes but maximum metabolic rate decreased drastically with body mass. Large fish, which are important for population growth due to reproductive hyperallometry, may therefore face a bioenergetic disadvantage and struggle most to perform optimally in future, warmer waters.

How are Conversations via an On-Demand Peer-To-Peer Emotional Well-Being App Associated with Emotional Improvement?

Non-clinical, on-demand peer-to-peer (PtP) support apps have become increasingly popular over the past several years. Although not as pervasive as general self-help apps, these PtP support apps are usually free and instantly connect individuals through live texting with a non-clinical volunteer who has been minimally trained to listen and offer support. To date, there is little empirical work that examines whether and how using an on-demand PtP support app improves emotional well-being. Applying regression and multilevel models to N = 1000+ PtP conversations, this study examined whether individuals experience emotional improvement following a conversation on a PtP support app (HearMe) and whether dyadic characteristics of the conversation - specifically, verbal and emotional synchrony - are associated with individuals' emotional improvement. We found that individuals reported emotional improvement following a conversation on the PtP support app and that verbal (but not emotional) synchrony was associated with the extent of individuals' emotional improvement. Our results suggest that online PtP support apps are a viable source of help. We discuss cautions and considerations when applying our findings to enhance the delivery of support provision on PtP apps.

Estimation of sensitivity and specificity of bulk tank milk PCR and 2 antibody ELISA tests for herd-level diagnosis of Mycoplasma bovis infection using Bayesian latent class analysis.

Mycoplasmosis (due to infection with Mycoplasma bovis) is a serious disease of beef and dairy cattle that can adversely impact health, welfare and productivity (Maunsell et al. (2011)). Mycoplasmosis can lead to a range of often severe, clinical presentations. Mycoplasma bovis (M. bovis) infection can present either clinically or subclinically, with the potential for recrudescence of shedding in association with stressful periods. Infection can be maintained within herds because of intermittent shedding (Calcutt et al., 2018, Hazelton et al., 2018). M. bovis is recognized as poorly responsive to treatment which represents a major challenge for control in infected herds. Given this, particular focus is needed on biosecurity measures to prevent introduction into uninfected herds in the first place. A robust and reliable laboratory test for surveillance is important both for herd-level prevention and control. The objective of this study was to estimate the sensitivity and specificity of 3 diagnostic tests (one PCR and 2 ELISA tests) on bulk tank milk, for the herd-level detection of M. bovis using Bayesian latent class analysis. In autumn 2018, bulk tank milk samples from 11,807 herds, covering the majority of the main dairy regions in Ireland had been submitted to the Department of Agriculture testing laboratory for routine surveillance were made available. A stratified random sample approach was used to select a cohort of herds for testing from this larger sample set. A final study population of 728 herds had bulk tank milk samples analyzed using a Bio-X ELISA (ELISA 1), an IDvet ELISA (ELISA 2) and a PCR test. A Bayesian latent class analysis (BLCA) was conducted to estimate the sensitivity (Se) and specificity (Sp) of the 3 diagnostic tests applied to bulk tank milk (BTM) for the detection of the herd-level infection. An overall LCA was conducted on all herds within a single population (a 3-test, 1-population model). The herds were also split into 2 populations based on herd size (small herds had < 82 cattle) (a 3-test, 2-population model) and separately into 3 regions in Ireland (Leinster, Munster and Connacht/Ulster) (a 3-test, 3-population model). The latent variable of interest was the herd-level M. bovis infection status. In total, 363/728 (50%) were large herds, 7 (1.0%) were positive on PCR, 88 (12%) positive on ELISA 1, and 406 (56%) positive on ELISA 2. Based on the 2-population model, the sensitivity (95% Bayesian credible interval (BCI) was 0.03 (0.02, 0.05), 0.22 (0.18, 0.27), 0.94 (0.88, 0.98) for PCR, ELISA 1 and ELISA 2 respectively. The specificity (95% BCI) was 0.99 (0.99, 1.0), 0.97 (0.95, 0.99), and 0.92 (0.86, 0.97) for PCR, ELISA 1 and ELISA 2 respectively. The herd-level true prevalence was estimated at 0.43 (BCI 0.35, 0.5) for smaller herds. The true prevalence was estimated at 0.62 (BCI 0.55, 0.69) for larger herds. The true prevalence was estimated at 0.56 (BCI 0.49, 0.463) in the 1-population model. For the 3-population model, the sensitivity (95% BCI) was 0.03 (0.02, 0.05), 0.24 (0.18, 0.29), 0.95 (0.9, 0.98) for PCR, ELISA 1 and ELISA 2 respectively. The specificity (95% BCI) was 0.99 (0.99, 1.0), 0.98 (0.96, 0.99), and 0.88 (0.79, 0.95) for PCR, ELISA 1 and ELISA 2 respectively. The herd-level true prevalence (95% BCI) was estimated at 0.65 (0.56, 0.73), 0.38 (0.28, 0.46) and 0.53 (0.4, 0.65) for population 1, 2, 3 respectively. Across all 3 models, the range in true prevalence was 38% to 65% of Irish dairy herds infected with M. bovis. The operating characteristics vary substantially between tests. The IDvet ELISA had a relatively high Se (the highest Se of the 3 tests studied) but it was estimated at 0.95 at its highest in 3-test, 3-population model. This test may be an appropriate test for herd-level screening or prevalence estimation within the context of the endemically infected Irish dairy cattle population. Further work is required to optimize this test and its interpretation when applied at herd-level to offset concerns related to the lower than optimal test Sp.

Unsaturation in the air spaces of leaves and its implications.

Modern plant physiological theory stipulates that the resistance to water movement from plants to the atmosphere is overwhelmingly dominated by stomata. This conception necessitates a corollary assumption-that the air spaces in leaves must be nearly saturated with water vapour; that is, with a relative humidity that does not decline materially below unity. As this idea became progressively engrained in scientific discourse and textbooks over the last century, observations inconsistent with this corollary assumption were occasionally reported. Yet, evidence of unsaturation gained little traction, with acceptance of the prevailing framework motivated by three considerations: (1) leaf water potentials measured by either thermocouple psychrometry or the Scholander pressure chamber are largely consistent with the framework; (2) being able to assume near saturation of intercellular air spaces was transformational to leaf gas exchange analysis; and (3) there has been no obvious mechanism to explain a variable, liquid-phase resistance in the leaf mesophyll. Here, we review the evidence that refutes the assumption of universal, near saturation of air spaces in leaves. Refining the prevailing paradigm with respect to this assumption provides opportunities for identifying and developing mechanisms for increased plant productivity in the face of increasing evaporative demand imposed by global climate change.

Social determinants of health inequalities in early phase clinical trials in Northern England.

BACKGROUND: Early phase clinical trials in Oncology represent a subspecialised area where UK patient selection is influenced by access to Experimental Cancer Medicine Centres (ECMCs). Equity of access with respect to social determinants of health (SDoH) were explored for two major ECMCs. METHODS: A retrospective cohort study including all referrals to Newcastle and Manchester ECMCs in 2021 was completed. Consent to screening or pre-screening was stratified against SDoH characteristics, including: Index of Multiple Deprivation (IMD) decile, ethnicity and distance to centre. RESULTS: 1243 patients were referred for trials. IMD quintile 1 (most deprived) patients had reduced likelihood of referral compared to expected population models (OR, 0.67; 95% CI: 0.55 to 0.80, p = <0.0001). IMD quintile 5 (least deprived) had increased likelihood of referral (OR, 1.46; 95% CI: 1.17 to 1.82, p = 0.0007). Living beyond median distance from Manchester reduced the likelihood of consenting to trials (OR, 0.72; 95% CI: 0.55 to 0.94, p = 0.015). Ethnicity data represented a White British propensity. CONCLUSIONS: Inequalities in socioeconomic and geographic factors influence referral and enrolment to early phase clinical trials in Northern England. This has implications for equity of access and generalisability of trial results internationally and warrants further study.

Udder health outcomes in Irish herds participating in cellcheck dry cow consults.

The CellCheck Dry Cow Consult (DCC) was developed by the CellCheck Technical Working Group to enable farmers to engage with their nominated vet to develop farm-specific selective dry cow therapy (SDCT) plans, where appropriate. This study evaluated the effect of the DCC on farmer decision-making around dry cow therapy, and the udder health impact of implementing SDCT, in study herds over the 2019 and 2020 dry periods. The DCC was a 3-h consult, delivered and funded as part of the Targeted Advisory Service on Animal Health (TASAH). Herds that completed a DCC were invited to register for a Dry Cow Review the following year. The combined data set for analysis across both years comprised of 439 herds and 25,357 cows. Available herd size ranged from 25 to 800. The median SCC of cows dried off with teat sealant only was 47,000 cells/ml before drying off in 2019 and 48,000 cells/ml at first milk recording in 2020, and 43,000 cells/ml before drying off in 2020 and 39,000 cells/ml at first milking recording in 2021. Following both the 2019 and 2020 dry periods, cows tended to converge toward a similar median SCC early in the following lactation, irrespective of prior dry cow treatment strategy. The uptake of SDCT was greater in Review herds, with 21% of cows receiving teat sealant only in 2020, compared with 16.3% of cows in herds participating in a Consult for the first time in 2020. At an individual cow level, in both years dry period new infection rate (NIR) was approximately 2.7% higher for cows treated with teat sealant only, than for those treated with both dry cow antibiotic tubes and teat sealant, and 1.2% higher than cows treated with antibiotic only. Regardless of treatment, there was a significant association between increasing parity and the risk of a dry period new infection. Increasing herd size had a statistically significant effect on the risk of dry period new infection rates. At a herd level, there was no statistically significant increase in NIR when SDCT was used compared with herds where blanket dry cow therapy was used. While not without risk, SDCT can be successfully implemented in Irish herds; however, constant attention to hygiene and management is essential. Though there are challenges to face, facilitating continued farmer education and engagement with professional guidance will be important.

Accuracy of intra ocular lens calculation formulae in patients with pseudoexfoliation syndrome.

BACKGROUND: The purpose of this study was to investigate the visual and refractive outcomes in patients with pseudoexfoliation (PXF) undergoing routine cataract surgery and to compare the accuracy of intraocular lens (IOL) power calculation formulae. METHODS: Retrospective case-series study from Shamir medical center, a public hospital, Israel. Medical records of patients who underwent routine cataract surgery between January 2019 and August 2021 were investigated. Postoperative visual acuity and manifest refraction were examined. The error in predicted refraction and IOL power calculation accuracy within a range of ± 0.50 to ± 1.00 diopters were compared between different IOL calculating formulae. RESULTS: 151 eyes of 151 patients ages 73.9 ± 7.1 years were included in this study- 58 eyes in the PXF group and 93 eyes in the control group. The mean absolute error (MAE) for the BUII formula was 0.63D ± 0.87 for the PXF group and 0.36D ± 0.48 for the control group (p < 0.05). The MAE for the Hill-RBF 3.0 formula was 0.61D ± 0.84 for the PXF group and 0.42D ± 0.55 for the control group (p = 0.05). There were significant differences in MAE and MedAE between PXF group and control group measures (p < 0.05). In the PXF group there were no significant differences between the different formulae. CONCLUSIONS: There were significant differences in accuracy of IOL power calculations in all formulae between PXF group and control group measures. PXF patients show hyperopic shift from predicted refraction. Barret universal II formula had the highest proportion of eyes with absolute error in prediction below or equal to 0.50 D in both PXF and control groups.

Estimating maximum oxygen uptake of fishes during swimming and following exhaustive chase - different results, biological bases and applications.

The maximum rate at which animals take up oxygen from their environment (MO2,max) is a crucial aspect of their physiology and ecology. In fishes, MO2,max is commonly quantified by measuring oxygen uptake either during incremental swimming tests or during recovery from an exhaustive chase. In this Commentary, we compile recent studies that apply both techniques to the same fish and show that the two methods typically yield different mean estimates of MO2,max for a group of individuals. Furthermore, within a group of fish, estimates of MO2,max determined during swimming are poorly correlated with estimates determined during recovery from chasing (i.e. an individual's MO2,max is not repeatable across methods). One explanation for the lack of agreement is that these methods measure different physiological states, each with their own behavioural, anatomical and biochemical determinants. We propose that these methods are not directly interchangeable but, rather, each is suited to address different questions in fish biology. We suggest that researchers select the method that reflects the biological contexts of their study, and we advocate for the use of accurate terminology that acknowledges the technique used to elevate MO2 (e.g. peak MO2,swim or peak MO2,recovery). If the study's objective is to estimate the 'true' MO2,max of an individual or species, we recommend that pilot studies compare methods, preferably using repeated-measures designs. We hope that these recommendations contribute new insights into the causes and consequences of variation in MO2,max within and among fish species.

N-of-1 Trial of Angina Verification Before Percutaneous Coronary Intervention.

BACKGROUND: In stable coronary artery disease, 30% to 60% of patients remain symptomatic despite successful revascularization. Perhaps not all symptoms reported by a patient with myocardial ischemia are, in fact, angina. OBJECTIVES: This study sought to determine whether independent symptom verification using a placebo-controlled ischemic stimulus could distinguish which patients achieve greatest symptom relief from percutaneous coronary intervention (PCI). METHODS: ORBITA-STAR was a multicenter, n-of-1, placebo-controlled study in patients undergoing single-vessel PCI for stable symptoms. Participants underwent 4 episodes (60 seconds each) of low-pressure balloon occlusion across their coronary stenosis, randomly paired with 4 episodes of placebo inflation. Following each episode, patients reported the similarity of the induced symptom in comparison with their usual symptom. The similarity score ranged from -10 (placebo replicated the symptom more than balloon occlusion) to +10 (balloon occlusion exactly replicated the symptom). The primary endpoint was the ability of the similarity score to predict symptom relief with PCI. RESULTS: Fifty-one patients were recruited, aged 62.9 ± 8.6 years. The median fractional flow reserve was 0.68 (Q1-Q3: 0.57-0.79), and the instantaneous wave-free ratio was 0.80 (Q1-Q3: 0.48-0.89). The median similarity score was 3 (Q1-Q3: 0.875-5.25). The similarity score was a strong predictor of symptom improvement following PCI: a patient with an upper quartile similarity score of 5.25 was significantly more likely to have lower angina frequency at follow-up (OR: 8.01; 95% credible interval: 2.39-15.86) than a patient with a lower quartile similarity score of 0.875 (OR: 1.31; 95% credible interval: 0.71-1.99), Pr(difference) >99.9%. CONCLUSIONS: Similarity score powerfully predicted symptom improvement from PCI. These data lay the foundation for independent symptom mapping to target PCI to those patients most likely to benefit. (Systematic Trial of Angina Assessment Before Revascularization [ORBITA-STAR]; NCT04280575).

Strong habitat and seasonal phenology effects on the evolution of self-compatibility, clonality and pollinator shifts in Lachenalia (Asparagaceae: Scilloideae).

Plants employ a diversity of reproductive safeguarding strategies to circumvent the challenge of pollen limitation. Focusing on southern African Lachenalia (Asparagaceae: Scilloideae), we test the hypothesis that the evolution of reproductive safeguarding traits (self-compatibility, autonomous selfing, bird pollination and clonal propagation) is favoured in species occupying conditions of low insect abundance imposed by critically infertile fynbos heathland vegetation and by flowering outside the austral spring insect abundance peak. We trace the evolution of these traits and selective regimes on a dated, multi-locus phylogeny of Lachenalia and assess their evolutionary associations using ordinary and phylogenetic regression. Ancestral state reconstructions identify an association with non-fynbos vegetation and spring flowering as ancestral in Lachenalia, the transition to fynbos vegetation and non-spring flowering taking place multiple times. They also show that self-compatibility, autofertility, bird pollination and production of multiple clonal offsets have evolved repeatedly. Regression models suggest that bird pollination and self-compatibility are selected for in fynbos and in non-spring flowering lineages, with autofertility being positively associated with non-spring flowering. These patterns support the interpretation of these traits as reproductive safeguarding adaptations under reduced insect pollinator abundance. We find no evidence to support the interpretation of clonal propagation as a reproductive safeguarding strategy.

Interplay between Mg2+ and Ca2+ at multiple sites of the ryanodine receptor.

RyR1 is an intracellular Ca2+ channel important in excitable cells such as neurons and muscle fibers. Ca2+ activates it at low concentrations and inhibits it at high concentrations. Mg2+ is the main physiological RyR1 inhibitor, an effect that is overridden upon activation. Despite the significance of Mg2+-mediated inhibition, the molecular-level mechanisms remain unclear. In this work we determined two cryo-EM structures of RyR1 with Mg2+ up to 2.8 Å resolution, identifying multiple Mg2+ binding sites. Mg2+ inhibits at the known Ca2+ activating site and we propose that the EF hand domain is an inhibitory divalent cation sensor. Both divalent cations bind to ATP within a crevice, contributing to the precise transmission of allosteric changes within the enormous channel protein. Notably, Mg2+ inhibits RyR1 by interacting with the gating helices as validated by molecular dynamics. This structural insight enhances our understanding of how Mg2+ inhibition is overcome during excitation.

Recognising the importance and impact of Imaging Scientists: Global guidelines for establishing career paths within core facilities.

In the dynamic landscape of scientific research, imaging core facilities are vital hubs propelling collaboration and innovation at the technology development and dissemination frontier. Here, we present a collaborative effort led by Global BioImaging (GBI), introducing international recommendations geared towards elevating the careers of Imaging Scientists in core facilities. Despite the critical role of Imaging Scientists in modern research ecosystems, challenges persist in recognising their value, aligning performance metrics and providing avenues for career progression and job security. The challenges encompass a mismatch between classic academic career paths and service-oriented roles, resulting in a lack of understanding regarding the value and impact of Imaging Scientists and core facilities and how to evaluate them properly. They further include challenges around sustainability, dedicated training opportunities and the recruitment and retention of talent. Structured across these interrelated sections, the recommendations within this publication aim to propose globally applicable solutions to navigate these challenges. These recommendations apply equally to colleagues working in other core facilities and research institutions through which access to technologies is facilitated and supported. This publication emphasises the pivotal role of Imaging Scientists in advancing research programs and presents a blueprint for fostering their career progression within institutions all around the world.

Learning algorithms for identification of whisky using portable Raman spectroscopy.

Reliable identification of high-value products such as whisky is vital due to rising issues of brand substitution and quality control in the industry. We have developed a novel framework that can perform whisky analysis directly from raw spectral data with no human intervention by integrating machine learning models with a portable Raman device. We demonstrate that machine learning models can achieve over 99% accuracy in brand or product identification across twenty-eight commercial samples. To demonstrate the flexibility of this approach, we utilized the same algorithms to quantify ethanol concentrations, as well as measuring methanol levels in spiked whisky samples. To demonstrate the potential use of these algorithms in a real-world environment we tested our algorithms on spectral measurements performed through the original whisky bottle. Through the bottle measurements are facilitated by a beam geometry hitherto not applied to whisky brand identification in conjunction with machine learning. Removing the need for decanting greatly enhances the practicality and commercial potential of this technique, enabling its use in detecting counterfeit or adulterated spirits and other high-value liquids. The techniques established in this paper aim to function as a rapid and non-destructive initial screening mechanism for detecting falsified and tampered spirits, complementing more comprehensive and stringent analytical methods.

Using Carbon Stable Isotopes to Study C3 and C4 Photosynthesis: Models and Calculations.

Stable carbon isotopes are a powerful tool to study photosynthesis. Initial applications consisted of determining isotope ratios of plant biomass using mass spectrometry. Subsequently, theoretical models relating C isotope values to gas exchange characteristics were introduced and tested against instantaneous online measurements of 13C photosynthetic discrimination. Beginning in the twenty-first century, laser absorption spectroscopes with sufficient precision for determining isotope mixing ratios became commercially available. This has allowed collection of large data sets at lower cost and with unprecedented temporal resolution. More data and accompanying knowledge have permitted refinement of 13C discrimination model equations, but often at the expense of increased model complexity and difficult parametrization. This chapter describes instantaneous online measurements of 13C photosynthetic discrimination, provides recommendations for experimental setup, and presents a thorough compilation of equations available to researchers. We update our previous 2018 version of this chapter by including recently improved descriptions of (photo)respiratory processes and associated fractionations. We discuss the capabilities and limitations of the diverse 13C discrimination model equations and provide guidance for selecting the model complexity needed for different applications.