bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimizing initial stocking densities of wild coral spawn slicks for mass production of larvae and settled corals for restoration
Authors: Langley Christina , Harrison Peter L. , Doropoulos Christopher
Published: July 2024

Mass culturing coral larvae collected from spawn slicks during spawning events and rearing them directly on reefs is an important method for coral reef restoration as it utilizes high genetic diversity and is readily upscaled. Understanding optimal initial stocking densities in mass cultures is, therefore, central to optimizing larval production efficiency. Yet, no studies have focused on optimizing initial stocking densities while coral embryos are still floating, despite the influence of density‐dependent effects during larval culturing. This study aimed to (1) explore initial stocking densities based on slick coverage and (2) determine the effects of initial densities on embryo development to coral settlement and early post‐settlement survival. Wild coral spawn slicks were collected at Lizard Island and reared at different combinations of slick coverage and density based on tank volume. Immediate density‐dependent effects were observed in treatments with 45% slick coverage, which had lower abundances of embryos 12 hours post‐spawning. The 12‐hour embryo densities ranged from 1.7 to 10.7 mL−1 and continued to display a negative relationship between density and survival of developing larvae. Overall, a density of approximately 5.1 embryos mL‐1 was the optimal stocking density for larval survival to competency (16.5%). The proportion of settlement and early post‐settlement survival was negatively correlated with higher initial densities, while a positive relationship was observed between the abundance of competent larvae and those settled, including initial settlers and 2‐month‐old recruits. These results highlight the importance of both larval quality and supply, and opportunities for site and system‐specific optimization of larval production in future work.
Reflexive EU environmental law: Exploring divergence in the French and German transposition of the Single‐use Plastics Directive
Authors: Ross Violet , de Almeida Lucila , van Leeuwen Judith , van Zeben Josephine
Published: July 2024

Reflexive environmental law (REL) techniques create potential for reflexivity by regulated companies. This reflexivity is fundamental to overcoming various regulatory hurdles posed by complex and dynamic sustainability challenges, such as plastics circularity. However, even when European Union (EU) environmental legislation incorporates REL techniques, Member State transposition may either undermine or enhance these techniques' potential for driving regulatee reflexivity. This article examines REL's evolution within complex, transnational legislative frameworks, taking the EU's Single‐use Plastics Directive (SUPD) as a case study. It compares reflexivity techniques in the SUPD to those in transpositions by France and Germany. Our analysis is based on the coding of 11 REL techniques and three overarching reflexive drivers—autonomy, accountability and adjustability—within four SUPD instruments. Identifying divergence in REL between the SUPD and Member State transpositions allows us to highlight three explanations as to why REL evolves in certain ways through the transposition process.
Thoracic Society of Australia and New Zealand clinical practice guideline on adult home oxygen therapy
Authors: McDonald Christine F. , Serginson John , AlShareef Saad , Buchan Catherine , Davies Huw , Miller Belinda R. , Munsif Maitri , Smallwood Natasha , Troy Lauren , Khor Yet Hong
Published: July 2024

This Thoracic Society of Australia and New Zealand Guideline on the provision of home oxygen therapy in adults updates a previous Guideline from 2015. The Guideline is based upon a systematic review and meta‐analysis of literature to September 2022 and the strength of recommendations is based on GRADE methodology. Long‐term oxygen therapy (LTOT) is recommended for its mortality benefit for patients with COPD and other chronic respiratory diseases who have consistent evidence of significant hypoxaemia at rest (PaO2 ≤ 55 mm Hg or PaO2 ≤59 mm Hg in the presence of hypoxaemic sequalae) while in a stable state. Evidence does not support the use of LTOT for patients with COPD who have moderate hypoxaemia or isolated nocturnal hypoxaemia. In the absence of hypoxaemia, there is no evidence that oxygen provides greater palliation of breathlessness than air. Evidence does not support the use of supplemental oxygen therapy during pulmonary rehabilitation in those with COPD and exertional desaturation but normal resting arterial blood gases. Both positive and negative effects of LTOT have been described, including on quality of life. Education about how and when to use oxygen therapy in order to maximize its benefits, including the use of different delivery devices, expectations and limitations of therapy and information about hazards and risks associated with its use are key when embarking upon this treatment.
Home oxygen guidelines: We do not know enough about LTOT
Authors: Branson Richard D.
Published: July 2024

See related article
Performance and Fatigue Patterns in Elite Cyclists During 6 h of Simulated Road Racing
Authors: Klaris Magnus Bak , Cubel Claes , Bruun Tim Ravn , Stampe Daniel , Rørvik Stian , Fischer Mads , Bonne Thomas , Christensen Peter M. , Piil Jacob Feder , Nybo Lars
Published: July 2024

Fatigue resistance is vital for success in elite road cycling, as repeated, intense efforts challenge the athletes' ability to sustain peak performance throughout prolonged races. The present study combined recurrent performance testing and physiological measures during 6 h simulated racing with laboratory testing to investigate factors influencing fatigue resistance. Twelve male national elite cyclists (25 ± 3 years; 76 ± 6 kg and VO2max of 5.2 ± 0.5 L/min) completed incremental power and maximal fat oxidation tests. Subsequently, they underwent field testing with physiological measures and fatigue responses evaluated through peak sprint power and 5 km time trial (TT) testing after 0, 2, 4, and 6 h of exercise. Peak power declined from 1362 ± 176 W in first sprint to 1271 ± 152 W after 2 h (p < 0.01) and then stabilized. In contrast, TT mean power gradually declined from 412 ± 38 W in the first TT to 384 ± 41 W in the final trial, with individual losses ranging from 2% to 14% and moderately correlated (r2 = 0.45) to accumulated exercise time above lactate threshold. High carbohydrate intake (~90 g/h) maintained blood glucose levels, but post‐TT [lactate] decreased from 15.1 ± 2 mM to 7.1 ± 2.3 mM, while fat oxidation increased from 0.7 ± 0.3 g/min at 0 h to 1.1 ± 0.1 g/min after 6 h. The study identifies fatigue patterns in national elite cyclists. Peak sprint power stabilized after an initial impairment from 0 to 2 h, while TT power gradually declined over the 6 h simulated race, with increased differentiation in fatigue responses among athletes.
Distinguishing sympathisers, philanthropists, rusted on activists and radicals: Using person‐centred analyses in collective action research
Authors: Thomas Emma F. , Yip Lisette , Lizzio‐Wilson Morgana
Published: July 2024

Many of our theories and models within social psychology implicitly refer to ‘types’ or subgroups of people who engage in collective action (activists, protestors), or do not (sympathisers, bystanders). Other frameworks differentiate between actors based on their adoption of tactics (benevolents, activists, radicals). How, empirically, do we distinguish sympathisers from activists? Activists from radicals? This paper describes recent research that adopts person‐centred statistical approaches (e.g., latent profile analysis, latent transition analysis, latent growth mixture models) to address three contemporary puzzles of collective action research. We present research showing that the methods are useful in identifying and explaining sub‐groups of people who seek to bring about change in qualitatively different ways. The methods are also useful for understanding volatility in collective action as well as identifying and understanding variation in how people sustain, increase, or diminish their commitment over time. There is nothing so practical as a good method and person‐centred statistical approaches are an important complement to variable‐centred approaches in social psychological research on collective action.
Estimation of a regular conditional functional by conditional U‐statistic regression
Authors: Derumigny Alexis
Published: July 2024

U‐statistics constitute a large class of estimators, generalizing the empirical mean of a random variable  to sums over every ‐tuple of distinct observations of . They may be used to estimate a regular functional of the law of . When a vector of covariates is available, a conditional U‐statistic describes the effect of on the conditional law of given , by estimating a regular conditional functional . We state nonasymptotic bounds of general conditional U‐statistics and study their asymptotics too. Assuming a parametric model of the conditional functional of interest, we propose a regression‐type estimator based on conditional U‐statistics. Its theoretical properties are derived, first in a nonasymptotic framework and then in two different asymptotic regimes. Some examples are given to illustrate our methods.
Yield of repeat blood cultures in acute myeloid leukemia patients with febrile neutropenia and bacteremia following allogeneic hematopoietic stem cell transplant
Authors: Sheu Michael , Molina Garcia Sofia , Shrivastava Gautam , Patel Meera , Mushtaq Ali , Crilley Thomas , Anwer Faiz , Majeed Aneela
Published: July 2024

Introduction

This study explored the efficacy of repeat blood cultures in bacteremic acute myeloid leukemia (AML) patients following allogeneic hematopoietic stem cell transplantation (HSCT).

Methods

This was a retrospective study of AML patients who experienced febrile neutropenia (FN) and bacteremia following HSCT at the Taussig Cancer Center from January 1, 2019, to December 31, 2022. The primary endpoint was the rate of positive repeat blood cultures following initial positive blood culture.

Results

Fifty patients were included in the study. There were 50 occurrences of FN with positive initial blood cultures that were diagnosed following HSCT. Fifty initial sets of blood cultures and 96 sets of repeat blood cultures were drawn between the 50 occurrences of FN. Twelve of 96 (12.5%) repeat blood culture sets were positive for a pathogen, which occurred over nine of 50 (18.0%) episodes of FN. Three of 96 (3.2%) repeat blood culture sets grew a pathogen that differed from the pathogen that grew in the preceding positive blood culture.

Conclusion

Among bacteremic AML patients in the post‐HSCT period, the yield of repeat blood cultures for detecting previously detected and new pathogens was low.

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Hydraulic Transport of Large Solid Particles in Inclined Pipes Under Pulsating Flow Conditions
Authors: Masanobu Sotaro , Takano Satoru , Yamamoto Marcio , Park Hyun Jin , Tasaka Yuji , Murai Yuichi
Published: July 2024

The pressure loss due to the hydraulic transport of large solid particles should be predicted for the design of subsea mining systems. The mixture flow in a flexible jumper is expected to be unsteady during lifting operations in an actual mining system. The authors develop a one-dimensional mathematical model that predicts such pressure loss under pulsating mixture flows in a static inclined pipe assuming that the flow in the jumper is fully developed. An experiment is performed on the hydraulic transport of solid particles to obtain data for model validation. In this experiment, several kinds of solid particles are used: alumina beads, glass beads, and gravel. The experimental parameters are mixture velocity, solid concentration, pulsation period and amplitude of water velocity, and pipe inclination angle. The proposed model is validated through a comparison with experimental data. The validation confirms that the model is applicable for the prediction of the pressure loss in inclined pipes under pulsating flow conditions. Furthermore, we calculate the pressure loss due to the hydraulic transport of polymetallic sulfide ores using the proposed model. The calculation results show that the time-averaged pressure loss drastically varies with the pipe inclination angle, reaching its maximum value between the pipe inclination angles of 30 deg and 60 deg, at which the flow is inclined upward. The results also show that the amplitude of pressure loss pulsation differs little between pipe inclination angles and that the pulsation component of pressure loss should be considered in designing lifting systems.
Interference Effects on Flow-Induced Oscillation of Three Tandem Cylinders With Passive Turbulence Control
Authors: Li Huaijun , Bernitsas Michael M. , Sun Hai
Published: July 2024

The characteristics of flow-induced oscillation (FIO) of multiple tandem cylinders with passive turbulence control (PTC) change due to interference between PTC cylinders. Identifying positive and negative interferences is vital for designing marine structures involving PTC cylinders on elastic supports. Experiments on a single PTC cylinder, two PTC cylinders and three PTC cylinders in tandem were conducted to study the interferences due to placing an identical oscillating PTC cylinder upstream, downstream, and both upstream and downstream. Critical parameters (damping, stiffness) and Reynolds number (Re) are varied in the tests. The onset inflow velocity of oscillation is reduced and back-to-back vortex-induced vibration (VIV) and galloping is achieved, when placing interference cylinders in the vicinity of the basic oscillator. The interference due to the downstream cylinder enhances FIO of the basic oscillator. In the VIV region, one interference downstream cylinder is more effective than two interference downstream cylinders. In the galloping region, the enhancement improves for two interference cylinders for lower stiffness and damping ratios. The interference upstream cylinder tends to suppress FIO of the basic oscillator for higher stiffness. The suppression of one upstream cylinder is more vigorous than that of two upstream cylinders in the VIV region, and the opposite is true in the galloping region. When two interference cylinders are placed both downstream and upstream of the basic oscillator, its FIO is enhanced for the lower stiffness whilst it is suppressed for the higher stiffness.
A Waste Heat Assessment of a Manufacturing Facility With Consideration for Demand Matching Through Thermal Energy Storage
Authors: Gladen Adam C. , Xiao Xuelei , Zeller Alexander , Yu Yao
Published: July 2024

A waste heat assessment of a manufacturing facility was conducted. A physical survey identified potential waste heat sources. For these sources, the temporal fluctuations in temperature and flowrate, and the frequency of occurrence of the waste heat, were determined from measurements, calculations, and company records. The energy and exergy of the waste heat were calculated. The total annual waste heat is 36.5 TJ of energy, which represents 0.84 TJ of exergy. The boiler, plant vacuums, and chiller comprise 96% of the energy rejected and are the major contributors to the rejected exergy. Using the waste heat for space heating is evaluated. Based on fuel consumption in the boiler, the annual energy for space heating is estimated at 8.5 TJ. Theoretically, waste heat from the boiler flue, polypropylene dryers, and plant vacuums could meet up to 39% of this energy without storage. Simply allowing the vacuum exhausts to cool in the building could theoretically meet up to 27%. Models are developed to investigate using waste heat recovery and thermal energy storage (TES) to provide space heating for a prototype warehouse building, and estimates for the initial costs of the recovery system are developed. Modeling indicates that TES is highly beneficial for matching short-term demand fluctuations and for smoothing the temporal oscillations in the waste heat. A nine-month heating season is simulated to determine the fraction of the load met by the recovery system. A small amount of thermal storage, e.g., 12.5–25% of daily waste heat, improved the fraction of demand that could be met. Larger sizes had diminishing returns and significantly increased the initial cost and payback period. To reduce initial cost, a refined recovery system design that uses a TES as an intermediate and for storage is proposed. The study highlights the need to consider fluctuations in the waste heat supply and sink demand, for thermal storage, and to identify relatively simple modifications to recover waste heat.
Machine Learning Versus Empirical Models to Predict Daily Global Solar Irradiation in an Average Year: Homogeneous Parallel Ensembles Prevailed
Authors: De Souza Keith
Published: July 2024

Accurate predictive daily global horizontal irradiation models are essential for diverse solar energy applications. Their long-term performances can be assessed using average years. This study scrutinized 70 machine learning and 44 empirical models using two disjoint 5-year average daily training and validation datasets, each comprising 365 records and ten features. The features included day number, minimum and maximum air temperature, air temperature amplitude, theoretical and observed sunshine hours, theoretical extraterrestrial horizontal irradiation, relative sunshine, cloud cover, and relative humidity. Fourteen machine learning algorithms, namely, multiple linear regression, ridge regression, Lasso regression, elastic net regression, Huber regression, k-nearest neighbors, decision tree, support vector machine, multilayer perceptron, extreme learning machine, generalized regression neural network, extreme gradient boosting, gradient boosting machine, and light gradient boosting machine were trained, validated, and instantiated as base learners in four strategically designed homogeneous parallel ensembles—variants of pasting, random subspace, bagging, and random patches—which also were scrutinized, producing 70 models. Specific hyperparameters from the algorithms were optimized. Validation showed that at least two ensembles outperformed its individual model. Huber-subspace ranked first with a root mean square error of 1.495 MJ/m2/day. The multilayer perceptron was most robust to the random perturbations of the ensembles which extrapolate to good tolerance to ground-truth data noise. The best empirical model returned a validation root mean square error of 1.595 MJ/m2/day but was outperformed by 93% of the machine learning models with the homogeneous parallel ensembles producing superior predictive accuracies.
Dehydration of Onion Slices for Food Processing Application Using Internet of Things-Based Smart Solar Drying System
Authors: Walke Santosh , Mandake Manoj , Naniwadekar Makarand , Tapre Ravi
Published: July 2024

Indian onion producers experience significant economic losses as a result of the unpredictable fluctuations in onion prices during the harvesting and postharvest stages. To address these difficulties and increase farmers' earnings, the transformation of onions into value-added goods such as onion paste, onion powder, onion sauce, and onion oil has emerged as a possible option. The objective of this project is to create a smart solar drying system based on Internet of Things (IoT) technique specifically designed for the dehydration of recently harvested red onions. In April 2023, a series of five experimental tests were carried out, examining the effects of different onion slice thicknesses ranging from 2 mm to 4 mm, with intervals of 0.5 mm. Each trial consisted of running the dryer for a duration of 9 h, specifically from 9:00 a.m. to 6:00 p.m., throughout the daylight hours for three consecutive days. The experiment involved evaluating different drying characteristics, such as moisture content on dry and wet bases, shrinkage ratio, and thermal efficiency. The drying time required to achieve a 10% moisture level (w.b.) was reduced by 30.19%, 16.98%, 11.32%, and 3.77% when comparing a 4-mm slice thickness to thinner alternatives of 2 mm, 2.5 mm, 3 mm, and 3.5 mm, respectively. The dryer had a superior thermal efficiency of 27.89% when the thickness was 2 mm, in contrast to 19.50% when the thickness was 4 mm. Significantly, onions that were dehydrated from slices measuring 2 mm and 2.5 mm in thickness showed exceptional suitability for the production of powdered onion.
Study on Internal Load Distribution of Deep Groove Ball Bearings Considering Raceway Surface Waviness
Authors: Liu Ming , Xu Kunpeng , Wei Xingxiao , Liu Xu , Pei Xun , Wang Bo
Published: July 2024

A full circumferential contact mechanical modeling study considering the effect of the contact relationship between the waviness mesoscopic profile and the rolling element on bearing load distribution is carried out. In the model, a sinusoidal function is adopted to simulate the profile of the waviness section. According to the contact tangency condition, a model of the contact deformation relationship between a single rolling element and the raceways is established. On this basis, a full circumferential rolling element contact load distribution model of the bearing is established by introducing the contact deformations between all rolling elements and the raceway surfaces. Focusing on contact deformations between the full circumferential rolling elements and the raceways, this is a more accurate model and reflects the load distribution state inside the bearing more realistically. The correctness of the mechanical analysis model proposed in this article is verified by an average error of 3.06% between the more computationally efficient mechanical analysis model and a full finite element model. Further, based on the model, the influence of the waviness parameters on the load distribution inside the bearing under different types of load conditions is analyzed.
In Vitro Wear of Titanium Reinforced Hydroxyapatite Coatings in Simulated Body Fluid
Authors: Tiwari Srikant , Mishra S. B.
Published: July 2024

Titanium-reinforced hydroxyapatite (Ti-HAP) coatings have been deposited over 254 SMO stainless steel using a low-velocity oxygen fuel technique. FESEM, XRD, Vickers microhardness, and shear strength tests have been performed to characterize the developed coatings. Further, in vitro wear behaviors of the coatings were evaluated using a pin-on-disc wear tester in simulated body fluid. The results reveal that 40Ti-HAP coating possesses superior wear resistance compared to 60Ti-HAP, Ti, and HAP coatings, attributed to higher surface hardness and higher shear strength values. Amongst the tested samples, the friction coefficient was lower for Ti coating, followed by 60Ti-HAP composite coating. The surface roughness was a prominent factor in reducing the friction coefficient of coating samples. Local detachment and brittle fracture were the dominant wear modes in Ti-HAP coating, whereas an additional micro-plowing wear mode was observed in pure hydroxyapatite and titanium coating.
Molecular Structures, Tribological Properties, and Working Mechanisms of Sulfur- and Phosphorus-Free Organic Molybdenum as Additives in Lubricants: A Short Review
Authors: Qi Wei , Chen Lei , Liu Hui-Chuan , Lv Lin-Gao
Published: July 2024

Traditional oil-soluble organic molybdenum (OM) as friction modifiers (FMs) in engine oils contain sulfur and/or phosphorus. Both sulfur and phosphorus are detrimental to the automotive exhaust gas catalysts. Consequently, sulfur and phosphorus in commercial engine oils are limited seriously by laws. Recently, oil-soluble sulfur- and phosphorus-free organic molybdenum (SPFMo) has been developed and measured intensively. This article reviews the molecular structures, tribological properties, and working mechanisms of SPFMo as FM in oils. Some bottlenecks that constrain the wide applications of SPFMo in engine oils are also summarized. In addition, some routes for overcoming the bottlenecks are suggested. Finally, some potential developments of SPFMo in the future are proposed. This review will provide a comprehensive understanding of SPFMo to the researchers in the field of oil additives.
Optimal Design of Assembling Robot Considering Different Limb Topologies and Layouts
Authors: Lian Binbin , Guo Jinhua , He Zhiyuan , Song Yimin
Published: July 2024

A class of 5 degree-of-freedom (DoF) hybrid robots consisting of one translational and two rotational (1T2R) parallel module and 2 T serial module is presented for assembling in the aircraft cabin. The 1T2R parallel modules are with three limb topologies (PRS, RRS, and internal closed loop) and two layouts (symmetrical and “T” shape). Herein, P, R, and S denote prismatic, rotational, and spherical joints. This article presents the multi-objective optimization of the hybrid robot regarding different limb topology, limb layout, and corresponding dimensions as design variables. Considering demands from the in-cabin assembling, kinematic, linear stiffness along z-axis and total mass of the robot are the objectives. The Pareto fronts and cooperative equilibrium point (CEP) indicate that the robot with 3-PRS and 3-RRS parallel module have better performances than the one with internal closed loop. The overall performances of robot with symmetrical layout are superior than the one with “T” shape layout. In addition, two optimization methods are compared. One is to separately optimize six robots with specific topology and layout. The other is to optimize all design variables in a model. It is found that six robots have their own performance zones. Therefore, final optimums of two methods are close to each other. But optimization in one model is able to eliminate unfeasible topologies in the early stage of searching and thus is more efficient. Optimal module is 3-PRS with symmetrical layout. Experiments on the physical prototype validate performances of the optimal robot.
A Novel Head-Following Algorithm for Multi-Joint Articulated Driven Continuum Robots
Authors: Yang Jianyu , Li Xuanting , Sheng Zhongqi , Ma Xiaofeng , Shi Hui , Xie Hualong
Published: July 2024

Head-following (tracking) issue is a challenge in developing multijoint continuum robots. However, various approaches have been developed in head-following algorithm for articulated-driven mechanism (ADM) continuum robots, and problems still exist such as low end accuracy, large trajectory deviation, and low computational efficiency. This article presents a novel head-following (NHF) algorithm with high precision, small trajectory deviation, and high computational efficiency for multijoint ADM continuum robots. The proposed algorithm first uses the follow-the-leader (FTL) method to search for planning points. Second, the end-effector errors are calculated, split, and adjusted. Third, the error judgment set is assigned based on the error rate of the end-effector, and also the joints that need to be adjusted are determined. Finally, the joint angles are iteratively adjusted. In this article, the NHF algorithm is simulated on ADM continuum robots with separately 10, 20, and 31 joints. The result shows that, comparing with other FTL algorithms, NHF algorithm has the highest end accuracy, and the smallest trajectory deviation.
On the Development of High-Lift, High-Work Low-Pressure Turbines
Authors: Clark John P. , Paniagua Guillermo , Cukurel Beni
Published: July 2024

Here, we describe a combined design, numerical, and experimental program intended substantially to increase the lift and work of low-pressure turbine stages. This exercise is critically dependent upon the appropriate modeling of boundary-layer transition over airfoil surfaces. The effort proceeds through the design of turbine stages consistent with future unmanned air vehicle engine cycles. Then, a series of experiments are described that increase in complexity while driving the technology to more realistic embodiments. Representative experimental data are compared to pre-test predictions of the flow field, and it is shown that acceptable Reynolds-lapse behavior is achievable even for turbines with significantly increased lift and work over state-of-the-art systems. Additionally, it is shown that through the judicious use of appropriate flow control technologies, it is possible to improve further the lapse characteristics of very high-lift airfoils. Finally, the benefits of applying such high-lift, high-work low-pressure turbine components are outlined with respect to a notional aircraft system, and future experiments are proposed.
Comparing human and machine's use of coarticulatory vowel nasalization for linguistic classification
Authors: Zellou Georgia , Kim Lila , Gendrot Cédric
Published: July 2024

Anticipatory coarticulation is a highly informative cue to upcoming linguistic information: listeners can identify that the word is ben and not bed by hearing the vowel alone. The present study compares the relative performances of human listeners and a self-supervised pre-trained speech model (wav2vec 2.0) in the use of nasal coarticulation to classify vowels. Stimuli consisted of nasalized (from CVN words) and non-nasalized (from CVCs) American English vowels produced by 60 humans and generated in 36 TTS voices. wav2vec 2.0 performance is similar to human listener performance, in aggregate. Broken down by vowel type: both wav2vec 2.0 and listeners perform higher for non-nasalized vowels produced naturally by humans. However, wav2vec 2.0 shows higher correct classification performance for nasalized vowels, than for non-nasalized vowels, for TTS voices. Speaker-level patterns reveal that listeners' use of coarticulation is highly variable across talkers. wav2vec 2.0 also shows cross-talker variability in performance. Analyses also reveal differences in the use of multiple acoustic cues in nasalized vowel classifications across listeners and the wav2vec 2.0. Findings have implications for understanding how coarticulatory variation is used in speech perception. Results also can provide insight into how neural systems learn to attend to the unique acoustic features of coarticulation.
Glucose-oxygen deprivation constrains HMGCR function and Rac1 prenylation and activates the NLRP3 inflammasome in human monocytes
Authors: Raulien Nora , Friedrich Kathleen , Strobel Sarah , Raps Stefanie , Hecker Friederike , Pierer Matthias , Schilling Erik , Lainka Elke , Kallinich Tilmann , Baumann Sven , Fritz-Wallace Katarina , Rolle-Kampczyk Ulrike , von Bergen Martin , Aigner Achim , Ewe Alexander , Schett Georg , Cross Michael , Rossol Manuela , Wagner Ulf
Published: July 2024

Hypoxia and low glucose abundance often occur simultaneously at sites of inflammation. In monocytes and macrophages, glucose-oxygen deprivation stimulates the assembly of the NLRP3 inflammasome to generate the proinflammatory cytokine IL-1β. We found that concomitant glucose deprivation and hypoxia activated the NLRP3 inflammasome by constraining the function of HMG-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate kinase pathway. HMGCR is involved in the synthesis of geranylgeranyl pyrophosphate (GGPP), which is required for the prenylation and lipid membrane integration of proteins. Under glucose-oxygen deprivation, GGPP synthesis was decreased, leading to reduced prenylation of the small GTPase Rac1, increased binding of nonprenylated Rac1 to the scaffolding protein IQGAP1, and enhanced activation of the NLRP3 inflammasome. In response to restricted oxygen and glucose supply, patient monocytes with a compromised mevalonate pathway due to mevalonate kinase deficiency or Muckle-Wells syndrome released more IL-1β than did control monocytes. Thus, reduced GGPP synthesis due to inhibition of HMGCR under glucose-oxygen deprivation results in proinflammatory innate responses, which are normally kept in check by the prenylation of Rac1. We suggest that this mechanism is also active in inflammatory autoimmune conditions.
Evolutionary genomic analyses of canine
E. coli
infections identify a relic capsular locus associated with resistance to multiple classes of antimicrobials
Authors: Ceres Kristina , Zehr Jordan D. , Murrell Chloe , Millet Jean K. , Sun Qi , McQueary Holly C. , Horton Alanna , Cazer Casey , Sams Kelly , Reboul Guillaume , Andreopoulos William B. , Mitchell Patrick K. , Anderson Renee , Franklin-Guild Rebecca , Cronk Brittany D. , Stanhope Bryce J. , Burbick Claire R. , Wolking Rebecca , Peak Laura , Zhang Yan , McDowall Rebeccah , Krishnamurthy Aparna , Slavic Durda , Sekhon Prabhjot kaur , Tyson Gregory H. , Ceric Olgica , Stanhope Michael J. , Goodman Laura B.
Published: July 2024

Infections caused by antimicrobial-resistant
Escherichia coli
are the leading cause of death attributed to antimicrobial resistance (AMR) worldwide, and the known AMR mechanisms involve a range of functional proteins. Here, we employed a pan-genome wide association study (GWAS) approach on over 1,000
E. coli
isolates from sick dogs collected across the US and Canada and identified a strong statistical association (empirical
P
< 0.01) of AMR, involving a range of antibiotics to a group 1 capsular (CPS) gene cluster. This cluster included genes under relaxed selection pressure, had several loci missing, and had pseudogenes for other key loci. Furthermore, this cluster is widespread in
E. coli
and
Klebsiella
clinical isolates across multiple host species. Earlier studies demonstrated that the octameric CPS polysaccharide export protein Wza can transmit macrolide antibiotics into the
E. coli
periplasm. We suggest that the CPS in question, and its highly divergent Wza, functions as an antibiotic trap, preventing antimicrobial penetration. We also highlight the high diversity of lineages circulating in dogs across all regions studied, the overlap with human lineages, and regional prevalence of resistance to multiple antimicrobial classes.

IMPORTANCE

Much of the human genomic epidemiology data available for
E. coli
mechanism discovery studies has been heavily biased toward shiga-toxin producing strains from humans and livestock.
E. coli
occupies many niches and produces a wide variety of other significant pathotypes, including some implicated in chronic disease. We hypothesized that since dogs tend to share similar strains with their owners and are treated with similar antibiotics, their pathogenic isolates will harbor unexplored AMR mechanisms of importance to humans as well as animals. By comparing over 1,000 genomes with
in vitro
antimicrobial susceptibility data from sick dogs across the US and Canada, we identified a strong multidrug resistance association with an operon that appears to have once conferred a type 1 capsule production system.
The characteristics of autolysins associated with cell separation in
Bacillus subtilis
Authors: Li Rui , Chu Ronghao , Ban Rui
Published: July 2024

The peptidoglycan hydrolases responsible for the cell separation of
Bacillus subtilis
cells are collectively referred to as autolysins. However, the role of each autolysin in the cell separation of
B. subtilis
is not fully understood. In this study, we constructed a series of cell separation-associated autolysin deficient strains and strains overexpressing the transcription factors SlrR and SinR, and the morphological changes of these strains in liquid culture were observed. The results showed that the absence of D,L-endopeptidases CwlS and LytF only increased the cell chain length in the early exponential phase. The absence of D,L-endopeptidase LytE or N-acetylmuramyl-L-alanine amidase LytC can cause cells to form chains throughout the growth of
B. subtilis
, although the cell chain length was significantly shortened during the stationary phase. However, the absence of peptidoglycan N-acetylglucosaminidase LytD only caused minor defect in cell separation. Therefore, we concluded that LytE and LytC were the major autolysins that ensure the timely separation of
B. subtilis
daughter cells, whereas CwlS, LytF, and LytD were the minor autolysins. In addition, overexpression of the transcription factors SinR and SlrR in the
cwlS lytF lytC lytE
mutant enabled
B. subtilis
cells to form ultra-long chains in the vegetative phase, and its biomass level was basically the same as that of the wild type. This led to the conclusion that besides inhibiting the expression of
lytC
and
lytF
, the SinR–SlrR complex also has other potential mechanisms to inhibit cell separation.

IMPORTANCE

In this study, the effects of CwlS, LytC, LytD, LytF, LytE, and SinR–SlrR complex on the cell separation of
Bacillus subtilis
at different growth phases were studied, and an ultra-long-chained
B. subtilis
strain was constructed. In microbial fermentation, due to its large cell size, this ultra-long-chained
B. subtilis
strain may be more likely to be precipitated or intercepted during the removal of bacterial process with centrifugation and membrane filtration as the main methods, which is crucial to improve the purity of the product.
Trojan Horse virus delivering CRISPR-AsCas12f1 controls plant bacterial wilt caused by
Ralstonia solanacearum
Authors: Peng Shiwen , Xu Yanan , Qu Hao , Nong Fushang , Shu Fangling , Yuan Gaoqing , Ruan Lifang , Zheng Dehong
Published: July 2024

Plant bacterial wilt caused by
Ralstonia solanacearum
results in huge losses. Accordingly, developing an effective control method for this disease is urgently required. Filamentous phages, which do not lyse host bacteria and exert minimal burden, offer a potential biocontrol solution. A filamentous phage RSCq that infects
R. solanacearum
was isolated in this study through genome mining. We constructed engineered filamentous phages based on RSCq by employing our proposed approach with wide applicability to non-model phages, enabling the exogenous genes delivery into bacterial cells. CRISPR-AsCas12f1 is a miniature class 2 type V-F CRISPR-Cas system. A CRISPR-AsCas12f1-based gene editing system that targets the key virulence regulator gene
hrpB
was developed, generating the engineered phage RSCqCRISPR-Cas. Similar to the Greek soldiers in the Trojan Horse, our findings demonstrated that the engineered phage-delivered CRISPR-Cas system could disarm the key “weapon,”
hrpB
, of
R. solanacearum
, in medium and plants. Remarkably, pretreatment with RSCqCRISPR-Cas significantly controlled tobacco bacterial wilt, highlighting the potential of engineered filamentous phages as promising biocontrol agents against plant bacterial diseases.

IMPORTANCE

Bacterial disease, one of the major plant diseases, causes huge food and economic losses. Phage therapy, an environmentally friendly control strategy, has been frequently reported in plant bacterial disease control. However, host specificity, sensitivity to ultraviolet light and certain conditions, and bacterial resistance to phage impede the widespread application of phage therapy in crop production. Filamentous phages, which do not lyse host bacteria and exert minimal burden, offer a potential solution to overcome the limitations of lytic phage biocontrol. This study developed a genetic engineering approach with wide applicability to non-model filamentous phages and proved the application possibility of engineered phage-based gene delivery in plant bacterial disease biocontrol for the first.
Transcriptional responses of
Neisseria gonorrhoeae
to glucose and lactate: implications for resistance to oxidative damage and biofilm formation
Authors: Ayala Julio C. , Balthazar Jacqueline T. , Shafer William M.
Published: July 2024

Understanding how bacteria adapt to different environmental conditions is crucial for advancing knowledge regarding pathogenic mechanisms that operate during infection as well as efforts to develop new therapeutic strategies to cure or prevent infections. Here, we investigated the transcriptional response of
Neisseria gonorrhoeae
, the causative agent of gonorrhea, to L-lactate and glucose, two important carbon sources found in the host environment. Our study revealed extensive transcriptional changes that gonococci make in response to L-lactate, with 37% of the gonococcal transcriptome being regulated, compared to only 9% by glucose. We found that L-lactate induces a transcriptional program that would negatively impact iron transport, potentially limiting the availability of labile iron, which would be important in the face of the multiple hydrogen peroxide attacks encountered by gonococci during its lifecycle. Furthermore, we found that L-lactate-mediated transcriptional response promoted aerobic respiration and dispersal of biofilms, contrasting with an anaerobic condition previously reported to favor biofilm formation. Our findings suggest an intricate interplay between carbon metabolism, iron homeostasis, biofilm formation, and stress response in
N. gonorrhoeae
, providing insights into its pathogenesis and identifying potential therapeutic targets.

IMPORTANCE

Gonorrhea is a prevalent sexually transmitted infection caused by the human pathogen
Neisseria gonorrhoeae
, with ca. 82 million cases reported worldwide annually. The rise of antibiotic resistance in
N. gonorrhoeae
poses a significant public health threat, highlighting the urgent need for alternative treatment strategies. By elucidating how
N. gonorrhoeae
responds to host-derived carbon sources such as L-lactate and glucose, this study offers insights into the metabolic adaptations crucial for bacterial survival and virulence during infection. Understanding these adaptations provides a foundation for developing novel therapeutic approaches targeting bacterial metabolism, iron homeostasis, and virulence gene expression. Moreover, the findings reported herein regarding biofilm formation and L-lactate transport and metabolism contribute to our understanding of
N. gonorrhoeae
pathogenesis, offering potential avenues for preventing and treating gonorrhea infections.
A novel hypovirulence-associated Hadaka virus 1 (HadV1-LA6) in
Fusarium oxysporum
f. sp.
cubense
Authors: Lin Yinfu , Pan Guangqun , Qi Yanhua , Wang Bin , Jin Cheng , Fang Wenxia
Published: July 2024

Fusarium oxysporum
f. sp.
cubense
(
Foc
) poses a significant threat to banana crops as a lethal fungal pathogen. The global spread of
Foc
underscores the formidable challenges associated with traditional management methods in combating this pathogen. This study delves into the hypovirulence-associated mycovirus in
Foc
. From
Foc
strain LA6, we isolated and characterized a novel member of the
Hadakaviridae
family, named Hadaka virus 1 strain LA6 (HadV1-LA6). HadV1-LA6 comprises 10 genomic RNA segments, with RNA1 to RNA7 sharing 80.9%–95.0% amino acid sequence identity with known HadV1-7n, while RNA8 to RNA10 display significantly lower identity. HadV1-LA6 demonstrates horizontal transmission capabilities in an all-or-none fashion between different
Foc
strains via coculturing. Phenotypic comparisons highlight that HadV1-LA6 significantly reduces the growth rates of its host fungus under cell wall stress and oxidative stress conditions. Importantly, HadV1-LA6 attenuates
Foc
’s virulence in detached leaves and banana plants. This study represents the first introduction of a novel hypovirulence-associated Hadaka virus 1 in
Foc
.

IMPORTANCE

Fusarium wilt of banana (FWB) is a severe fungal disease caused by soil-borne
Fusarium oxysporum
f. sp.
cubense
(
Foc
). Among various strategies, biocontrol emerges as a safe, ecologically friendly, and cost-effective approach to managing FWB. In this study, we focus on exploring the potential of a novel hypovirulent member of hadakavirid, HadV1-LA6. Previous reports suggest that HadV1 shows no apparent effect on the host. However, through phenotypic assessments, we demonstrate that HadV1-LA6 significantly impedes the growth rates of its host fungus under stress conditions. More importantly, HadV1-LA6 exhibits a remarkable capacity to attenuate
Foc
’s virulence in detached leaves and banana plants. Furthermore, HadV1-LA6 could be horizontally transmitted between different
Foc
strains, presenting a promising resource for revealing the molecular mechanism of the interaction between Hadaka virus 1 and its host.
Spatial patterns of
Hyalomma marginatum
-borne pathogens in the Occitanie region (France), a focus on the intriguing dynamics of
Rickettsia aeschlimannii
Authors: Joly-Kukla Charlotte , Bernard Célia , Bru David , Galon Clémence , Giupponi Carla , Huber Karine , Jourdan-Pineau Hélène , Malandrin Laurence , Rakotoarivony Ignace , Riggi Camille , Vial Laurence , Moutailler Sara , Pollet Thomas
Published: July 2024

Hyalomma marginatum
is an invasive tick species recently established in mainland southern France. This tick is known to host a diverse range of human and animal pathogens. While information about the dynamics of these pathogens is crucial to assess disease risk and develop effective monitoring strategies, few data on the spatial dynamics of these pathogens are currently available. We collected ticks in 27 sites in the Occitanie region to characterize spatial patterns of
H. marginatum
-borne pathogens. Several pathogens have been detected:
Theileria equi
(9.2%),
Theileria orientalis
(0.2%),
Anaplasma phagocytophilum
(1.6%),
Anaplasma marginale
(0.8%), and
Rickettsia aeschlimannii
(87.3%). Interestingly, we found a spatial clustered distribution for the pathogen
R. aeschlimannii
between two geographically isolated areas with infection rates and bacterial loads significantly lower in Hérault/Gard departments (infection rate 78.6% in average) compared to Aude/Pyrénées-Orientales departments (infection rate 92.3% in average). At a smaller scale,
R. aeschlimannii
infection rates varied from one site to another, ranging from 29% to 100%. Overall, such high infection rates (87.3% on average) and the effective maternal transmission of
R. aeschlimannii
might suggest a role as a tick symbiont in
H. marginatum
. Further studies are thus needed to understand both the status and the role of
R. aeschlimannii
in
H. marginatum
ticks.

IMPORTANCE

Ticks are obligatory hematophagous arthropods that transmit pathogens of medical and veterinary importance. Pathogen infections cause serious health issues in humans and considerable economic loss in domestic animals. Information about the presence of pathogens in ticks and their dynamics is crucial to assess disease risk for public and animal health. Analyzing tick-borne pathogens in ticks collected in 27 sites in the Occitanie region, our results highlight clear spatial patterns in the
Hyalomma marginatum
-borne pathogen distribution and strengthen the postulate that it is essential to develop effective monitoring strategies and consider the spatial scale to better characterize the circulation of tick-borne pathogens.