bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectroscopic investigations of green synthesized zinc oxide nanoparticles (ZnO NPs): antioxidant and antibacterial activity
Authors: Tiwari Ajay Kumar , Jha Saket , Tripathi Sharad Kumar , Shukla Rohit , Awasthi Ram Raseele , Bhardwaj Abhishek Kumar , Singh Abhimanyu Kumar , Dikshit Anupam
Published: July 2024

In the recent decade, zinc oxide nanoparticles (ZnO NPs) have been widely explored owing to their versatile properties and prodigious demands in the drug delivery, medical, energy storage, cosmetics, and the healthcare sectors. Therefore, the current work opts for an environmentally benign method to prepare ZnO NPs. The leaf extract of Calendula officinalis L. acts as a reducing agent for the metal ions; therefore, in the current research, ZnO NPs were prepared via green route by using Calendula officinalis leaf extract. Furthermore, the ZnO NPs were analysed with different spectroscopic techniques to confirm the structure and stability of nanomaterials. The prepared ZnO NPs were characterized by XRD, FE-SEM, FT-IR and UV–Vis studies. Also, the antioxidant and antimicrobial properties of the synthesized ZnO NPs were investigated. The XRD result of synthesized ZnO NPs showed the crystalline size  28.23 nm with wurtzite hexagonal structure along with the most intense peak (101). Following preliminary confirmations of the intended ZnO NPs, both big and small agglomerated forms were observed in the FE-SEM, which is often used to determine their exterior assembly. Further, the results of Fourier transform infrared spectroscopy (FT-IR) indicated the formation of pure ZnO NPs with an absorption peak of the Zn–O bond between 4000 cm−1 and 500 cm−1 and no discernible peak in the monitoring range. The UV–Vis spectrum of the green synthesized ZnO NPs were revealed two prominent absorption peaks at 355 nm and 370 nm with energy band gap of 2.986 eV. Using the 1, 1-di phenyl-2-picrylhydrazyl (DPPH) test, the antioxidant activity of the described ZnO NPs was assessed. It demonstrated how, ZnO NPs significantly increased their antioxidant activity by scavenging 1, 1-di phenyl-2-picrylhydrazyl (DPPH) free radicals. It could be seen that synthesis of the naturally occurring plant product ZnO NPs have been acting as an alternate of chemical antioxidant. The antimicrobial analysis was also performed with the help of disk diffusion method where three multi-drug resistant human pathogens namely Staphylococcus aureus, Klebsiella pneumoniae and E.coli were used. The Zone of Inhibition diameter values are 35.2 mm ± 0.9, 23.6 mm ± 0.1 and 13.5 mm ± 0.1, respectively, which showed that the ZnO NPs was highly effective against S. aureus. Thus, the green synthesis method of ZnO NPs using leaf extract of Calendula officinalis is evidence that it is superior and environmentally friendly method for the preparation of ZnO NPs and hence it can be utilized in various nano-medicine approaches.
Pyrolysis assessment of palm kernel shell waste valorization to sulfonated magnetic biochar from techno-economic and energy perspectives
Authors: Seow Yee Xuan , Tan Yie Hua , Kansedo Jibrail , Tan Inn Shi , Chin Bridgid Lai Fui , Mubarak Nabisab Mujawar , Mohiddin Mohd Nurfirdaus Bin , Yek Peter Nai Yuh , Chan Yen San , Abdullah Mohammad Omar
Published: July 2024

Most agricultural activities generate a significant quantity of biomass waste that has not been fully utilized. This study utilized palm kernel shells as the primary material to produce sulfonated magnetic palm kernel shell biochar. The post-sulfonation magnetic palm kernel shell biochar had a greater particle size of around 137 nm compared to the pre-sulfonation biochar. This increase in size can be attributed to the presence of the − SO3H group. The biochar that underwent post-sulfonation was chosen for a techno-economic evaluation to ascertain its viability in terms of economics and energy efficiency. Soybean straw and coconut shell-derived biochar were chosen for the techno-economic assessment. The energy intake for soybean straws, coconut shells, and palm kernel shells derived from biochar is 48.85 MJ∙kg−1, 23.83 MJ∙kg−1, and 52.44 MJ∙kg−1, respectively. The energy output for soybean straws, coconut shells, and palm kernel shells derived biochar is determined to be 22.54 MJ∙kg−1, 23.68 MJ∙kg−1, and 31.55 MJ∙kg−1, respectively. The ultimate profit-to-cost ratios of soybean straws, coconut shells, and palm kernel shells derived biochar are 0.21, 4.92, and 1.11, respectively. The techno-economic assessment indicates that coconut shell-derived biochar production is favourable, primarily due to its attributes of low net energy balance, high porosity, and lower density. Both coconut shells and palm kernel shells derived biochar productions are economically viable and efficient due to their high profit-to-cost ratio. The microwave-assisted technology is proven efficient and demands less energy to generate an equivalent quantity of biochar compared to traditional furnaces.
Stable-isotope probing combined with amplicon sequencing and metagenomics identifies key bacterial benzene degraders under microaerobic conditions
Authors: Táncsics András , Bedics Anna , Banerjee Sinchan , Soares André , Baka Erzsébet , Probst Alexander J. , Kriszt Balázs
Published: July 2024

The primary aim of the present study was to reveal the major differences between benzene-degrading bacterial communities evolve under aerobic versus microaerobic conditions and to reveal the diversity of those bacteria, which can relatively quickly degrade benzene even under microaerobic conditions. For this, parallel aerobic and microaerobic microcosms were set up by using groundwater sediment of a BTEX-contaminated site and 13C labelled benzene. The evolved total bacterial communities were first investigated by 16S rRNA gene Illumina amplicon sequencing, followed by a density gradient fractionation of DNA and a separate investigation of “heavy” and “light” DNA fractions. Results shed light on the fact that the availability of oxygen strongly determined the structure of the degrading bacterial communities. While members of the genus Pseudomonas were overwhelmingly dominant under clear aerobic conditions, they were almost completely replaced by members of genera Malikia and Azovibrio in the microaerobic microcosms. Investigation of the density resolved DNA fractions further confirmed the key role of these two latter genera in the microaerobic degradation of benzene. Moreover, analysis of a previously acquired metagenome-assembled Azovibrio genome suggested that benzene was degraded through the meta-cleavage pathway by this bacterium, with the help of a subfamily I.2.I-type catechol 2,3-dioxygenase. Overall, results of the present study implicate that under limited oxygen availability, some potentially microaerophilic bacteria play crucial role in the aerobic degradation of aromatic hydrocarbons.
Hyperspectral Image Analysis Using Cloud-Based Support Vector Machines
Authors: Haut Juan M. , Franco-Valiente Jose M. , Paoletti Mercedes E. , Moreno-Álvarez Sergio , Pardo-Diaz Alfonso
Published: July 2024

Hyperspectral image processing techniques involve time-consuming calculations due to the large volume and complexity of the data. Indeed, hyperspectral scenes contain a wealth of spatial and spectral information thanks to the hundreds of narrow and continuous bands collected across the electromagnetic spectrum. Predictive models, particularly supervised machine learning classifiers, take advantage of this information to predict the pixel categories of images through a training set of real observations. Most notably, the Support Vector Machine (SVM) has demonstrate impressive accuracy results for image classification. Notwithstanding the performance offered by SVMs, dealing with such a large volume of data is computationally challenging. In this paper, a scalable and high-performance cloud-based approach for distributed training of SVM is proposed. The proposal address the overwhelming amount of remote sensing (RS) data information through a parallel training allocation. The implementation is performed over a memory-efficient Apache Spark distributed environment. Experiments are performed on a benchmark of real hyperspectral scenes to show the robustness of the proposal. Obtained results demonstrate efficient classification whilst optimising data processing in terms of training times.
Association between underweight status or low body mass index and the risk of developing superior mesenteric artery syndrome following scoliosis corrective surgery in pediatric patients: a review of the literature
Authors: Lamport Lyssa , DiMauro Jon-Paul , Johnson Stephani , Roberts Susan , Ziegler Jane
Published: July 2024

Superior mesenteric artery (SMA) syndrome is the compression of the third portion of the duodenum between the abdominal aorta and the superior mesenteric artery. Although multifactorial, the most frequent cause of SMA syndrome is significant weight loss and cachexia often induced by catabolic stress. SMA syndrome resulting from scoliosis surgery is caused by a reduction of the aortomesenteric angle and distance. Risk factors include rapid weight loss, malnutrition, and a rapid reduction in the mesenteric fat pad and are the most common causes of a decrease in the aortomesenteric angle and distance. Surgically lengthening the vertebral column can also lead to a reduction of the aortomesenteric distance, therefore, has been identified as a risk factor unique to spinal surgery. Despite a reported decline in SMA syndrome cases due to improved surgical techniques, duodenal compression is still a risk and remains a life-threatening complication of scoliosis surgery. This article is a cumulative review of the evidence of being underweight or having a low body mass index as risk factors for developing SMA syndrome following surgical scoliosis instrumentation and correction.
The influence of temperature and the magnetic field on Ni electrodeposition from citrate bath and its electrocatalytic performance towards hydrogen evolution reaction
Authors: Elsharkawy Safya , Kutyła Dawid , Boryczko Bożena , Żabiński Piotr
Published: July 2024

The demand for energy surpasses the available supply, leading to various economic, social, and environmental consequences. Hydrogen is one of the most clean and renewable source for energy. Therefore, the electrocatalytic hydrogen evolution reaction (HER) presents a promising eco-friendly approach for generating sustainable hydrogen energy. However, in alkaline conditions, HER encounters slow kinetics due to challenges associated with hydrogen adsorption and hydrolysis. In this article, thin Ni films were synthesized using the electrodeposition technique from citrate electrolyte. Their suitability as electrocatalysts for the hydrogen evolution reaction (HER) in a 1 M NaOH solution was estimated. This research investigates how the uniform magnetic field and temperature affect the process of nickel electrodeposition from a citrate bath and its subsequent influence on surface morphology and catalytic properties for the hydrogen evolution reaction (HER). Additionally, alterations in surface material wettability were examined based on changing the temperature during using the magnetic field for the electrodeposition process and shows how this effect on the catalytic performance towards HER. The outputs show that using the magnetic field for fabrication of Ni thin films at room temperature enhances the surface morphology and its catalytic performance for HER. However, the study reveals that using the temperature for Ni electrodeposition improves its catalytic performance independently of the magnetic field, whereas combining temperature with the magnetic field for Ni thin film fabrication diminishes their catalytic performance for the hydrogen evolution reaction (HER). The nickel thin film produced at 25 °C under the influence of a magnetic field, whether parallel or perpendicular, demonstrates the lowest overpotential of − 268 mV to achieve a current density of 10 mA cm−2. Additionally, it exhibits the smallest Tafel slope values of 106 mV dec−1 and 128 mV dec−1 for the parallel (Bǁ) and perpendicular (BꞱ) directions, respectively. However, the magnetic field effect diminishes at elevated temperatures. Nickel thin films prepared at 35 °C under the influence of perpendicular (BꞱ) and parallel (Bǁ) directions exhibit higher overpotential values of − 314 mV and − 322 mV, respectively.
Analysis of the Aquaponic System Sustainability via System Dynamics Modelling – FEW Nexus Approach
Authors: Francisco Erika Cristina , Freato Thiago Archangelo , Piolli Alessandro Luis , Poz Maria Ester Soares Dal
Published: July 2024

Aquaponic systems integrate aquaculture and hydroponics, recycling nutrient-enriched water from fish tanks to grow plants, significantly reducing carbon emissions, water use and production costs compared to other methods. It is considered a sustainable solution for food production, addressing issues such as climate change and eutrophication. Particularly valuable in family farming, it increases the diversity and quality of food, while reducing its environmental impact. However, despite its potential, aquaponics lacks recognition in public policies, making its widespread adoption difficult. Quantifying its benefits is crucial for strategic planning and the formulation of policies to support family farming and the transition to sustainability, in line with global objectives. Therefore, there is a need to comprehensively quantify the benefits of aquaponics, particularly in terms of the Food-Energy-Water (FEW) nexus, to support decision-making and policy formulation for sustainable agriculture. The nexus concept encompasses highly complex systems requiring robust tools capable of analysing the interrelationships between multiple components. Aiming to analyse the degree of sustainability of aquaponics systems on family property in the FEW nexus context, a System Dynamics Modelling (SDM) coupling Socio-economic and environmental indicators was developed. The results obtained demonstrated the efficiency of using SDM as an analysis and support tool for decision-making. Additionally, they prove the environmental viability of food production via aquaponic systems.
An overview of psychological factors in mobility choices: the impact on pro-environmental behavior
Authors: Pellegrini Marilina , Tagliabue Mariaelena
Published: July 2024

Despite the current increased spread of modern mobility options in urban areas aimed at inducing changes in mobility choices, their integration into daily life remains sporadic, reducing their potential impact on the adoption of shared mobility services as a usual mode of transport. This paper provides a literature review of established models of psychological factors, including values, beliefs, and personal norms, particularly focused on pro-environmental behaviors influencing mobility choices and facilitating the adoption of more sustainable transportation habits, often supported by technological advancements. We started considering the recent increase in the complexity of cities and mobility needs, which induced policymakers to pay attention to the sustainability of people’s movements by promoting various kinds of shared mobility options. Then, we illustrated the most consolidated models of psychological factors linked to ecological behaviors, also summarizing the main results present in the literature regarding variables that influence mobility choices. The final goal was to highlight crucial aspects that should be considered to foster the effective use of new modes of transportation to help reduce the environmental impact caused by traffic.
Phosphorus removal by free water surface constructed wetlands for the wastewater treatment: bibliometric and bibliographic review
Authors: de Paula Renato Zimiani , Fontana Luciane , de Jesus Tatiane Araujo
Published: July 2024

Constructed wetlands (CWs) are a widely used technology for the treatment of wastewater, with Free Water Surface Constructed Wetlands (FWS CWs) being the simplest configuration. However, there is currently no consensus on the Hydraulic Retention Time (HRT) that optimizes P removal efficiency. To address this issue, this study conducted a bibliometric review of 85 scientific articles published between 1997 and 2021 that investigated the relationship between P removal and the HRT in FWS CWs. Scientometric maps were constructed to identify key topics, and bibliometric surveys were used to refine and explore the relationship between P removal and HRT. The analysis found a high correlation between P removal and HRT across all scales of the FWS CW systems, ranging from moderate to very strong. Specifically, the regressions between P removal efficiency and HRT were 73%, 70%, and 67% for lab-scale, pilot-scale, and real-scale systems, respectively. Overall, the FWS CWs demonstrated strong P removal efficiency, with removal rates reaching 95%, making them a promising technology for the tertiary treatment of effluents with a focus on nutrient removal and recovery. Future studies that focus on the many parameters of CW, especially on how macrophytes management affects the nutrient removal performance of these systems, are necessary to enrich our knowledge of CWs and optimize the application of this technology to wastewater treatment.
Geospatial insights into groundwater contamination from urban and industrial effluents in Faisalabad
Authors: Quddoos Abdul , Muhmood Khalid , Naz Iram , Aslam Rana Waqar , Usman Syed Yasir
Published: July 2024

Groundwater remains the most dependable resource for various essential uses such as drinking, cleansing, agricultural irrigation, and industrial applications. In urban areas, the dependency on groundwater to meet water demands is significant. However, this resource faces threats from overuse and poor management, leading to a degradation in quality primarily due to the unchecked release of industrial and household wastes. The escalation of industrial activities and rapid urban growth have amplified the volume of wastewater, adversely affecting the purity of freshwater sources within aquifers. This investigation focuses on evaluating the impact of industrial and urban effluents on groundwater quality in the city of Faisalabad. The main contributors to groundwater pollution include the indiscriminate disposal of industrial and urban effluents through unlined drains and the extensive application of chemical agents in agriculture, such as fertilizers, and pesticides. To understand the physiochemical properties of both, drain and groundwater, samples were collected at various distances 50 m, 100 m, and 150 m from drain outlets. This study utilized Geographic Information Systems (GIS) to accurately map and analyze the distribution and impact of contaminants. Parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness, bicarbonates, calcium and magnesium hardness, and chloride levels were examined. The findings indicated that contaminant levels were highest in drain water and increased in concentration the closer they were to the drainage sources, with the exception of pH levels. All samples exceeded the World Health Organization's (WHO) safe limits, deeming them unfit for use. This finding indicates widespread contamination, posing significant public health risks and highlighting the urgent need for improved waste management and water treatment practices in Faisalabad. It underscores the critical importance of implementing effective pollution control measures to safeguard public health and ensure water security in the region. However, a notable correlation was observed between the concentration of pollutants in drain water and key indicators such as EC, TDS, total hardness, and magnesium hardness, highlighting their role in deteriorating aquifer water quality. Moreover, groundwater samples collected 50 m from drains exhibited the highest pollutant concentrations compared to those taken further away, at 100 m and 150 m distances.
Implementing Australia’s first national cancer control plan to shape Australian cancer control policy for the next decade and beyond
Authors: Chaji Daniel , Malloy Lisa , Meredyth David , Milch Vivienne , Toms Cindy , Howlett Claire , Keefe Dorothy
Published: July 2024

Cancer outcomes in Australia are among the best in the world, but this is not the story for all Australians, with significant disparities in cancer outcomes and experiences among specific groups in Australian society. The Australian Government developed the Australian Cancer Plan (the Plan) as a national approach to improve cancer outcomes and experience for all. The Plan identifies six strategic objectives that require nationally coordinated effort, to achieve the Plan’s vision of world class cancer outcomes and experience for all Australians affected by cancer. The Plan emphasises person-centred approaches to cancer care, underpinned by a Health Equity in Cancer Outcomes Framework. As the Australian Government’s national cancer control agency, Cancer Australia is driving the Plan’s reform agenda through five implementation policy priorities: the development and establishment of an Australian Comprehensive Cancer Network; the development of a National Optimal Care Pathways Framework; the development of a National Comprehensive Cancer Data Framework and minimum dataset; the development of a National Genomics in Cancer Control Framework; and initiatives to improve cancer outcomes for Aboriginal and Torres Strait Islander people. These priorities will lay the foundation to deliver an integrated, accessible, and equitable cancer control system to deliver the Plan’s vision over the next decade.
The Prevalence of Mycobacterium Tuberculosis Infection in Saudi Arabia: A Systematic Review and Meta-analysis
Authors: Said Badria , Mohamed Amal H. , Eltyeb Ebtihal , Eltayeb Raga , Abdalghani Nagla , Siddig Bahja , Ahmed Amel Eltahir Banaga , Balla Eltom Ali Anwar , Alhazmi Abdulaziz H.
Published: July 2024

The prevalence of Tuberculosis (TB) serves as a pivotal metric, reflecting the TB burden within a specific demographic. It quantifies the number of individuals affected by either active TB disease or latent TB (LTBI). Such data is crucial for assessing the efficacy of TB control interventions and determining the demand for diagnostic and treatment services. This study aims to consolidate data on TB infection prevalence in Saudi Arabia from existing literature. Additionally, we stratify this prevalence based on age, professional involvement in healthcare, gender, and region. Our search was conducted in PubMed, Scopus, Cochrane Library, and Web of Science databases to determine relevant studies. The pooled prevalence of TB infection among the total population residing in Saudi Arabia was estimated using a random-effect meta-analysis approach and Comprehensive Meta-Analysis software. The protocol was registered in the PROSPERO International Prospective Register of Systematic Reviews, No: CRD42023400984. We included 21 studies, 11 of which were pooled in the analysis. The overall prevalence was 17%.

Regarding the specific population, we found that the prevalence of TB in Saudi Arabia was 9.8% and 26.7% in the general population and the healthcare workers, respectively. Stratifying by age, the highest prevalence was observed in individuals over 50 years (33.0%), while the lowest was in the 10–19 age group (6.4%). In terms of gender, men had a higher prevalence (12.0%) compared to women (9.4%). The prevalence of TB in Riyadh was 6.4%, and 3.6% in Mecca and Medina. Among healthcare workers, nurses and physicians had a prevalence of 14.7% and 15.0%, respectively. Our study found a TB prevalence of 17.0% in Saudi Arabia, higher than the worldwide average of 12.0%. Men had a higher prevalence than women, and healthcare workers had a relatively low prevalence compared to other countries. Age was a significant risk factor, with the highest prevalence in individuals above 50 years. Standardized protocols for screening and diagnosis and targeted interventions are needed to combat TB effectively in the country.
Advancing Insights into Large-Artery Stiffening in Humans Through the Application of Multi-omics
Authors: Dib Marie-Joe
Published: July 2024

A healthy aorta limits excess arterial pulsatility and protects the microvasculature from the effects of fluctuating blood flow and pressure. Aging and various pathologic states impair this cushioning function, a phenomenon known as large-artery stiffening (LAS). LAS is a common risk factor for a plethora of chronic diseases, and an important contributor to the conundrum of vascular morbidity. Importantly, LAS is pathologically different from atherosclerosis as it rather occurs primarily from changes in the medial aortic layer, and can manifest itself in the absence of plaque formation. Clinically, LAS is one of the few biological parameters that more than doubles with aging. With the advent of novel highly effective therapies for atherosclerosis, and the likely decline of other causes of death in the next few decades, prevention and treatment of increased LAS may be one of the most relevant strategies for preventing multimorbidity in aging populations in upcoming decades. LAS characterizes a high-priority therapeutic target to improve cardiovascular disease burden and associated comorbidities. This review aims to (i) provide an overview of insights from genetic research on LAS pathophysiology, and explore the scope of next-generation sequencing methods in the field arterial research; (ii) shed light on the utility of emerging state-of-the-art multi-omics approaches to unravel mechanisms underlying LAS to identify candidate therapeutic targets; (iii) highlight the potential of emerging state-of-the-art integrative multi-omics, motivating their use to address current gaps in understanding sex- and ancestry-specific mechanisms of LAS.
Dynamics-augmented cluster-based network model
Authors: Hou Chang , Deng Nan , Noack Bernd R.
Published: July 2024

In this study we propose a novel data-driven reduced-order model for complex dynamics, including nonlinear, multi-attractor, multi-frequency and multiscale behaviours. The starting point is a fully automatable cluster-based network model (CNM) (Li et al., J. Fluid Mech., vol. 906, 2021, A21) that kinematically coarse grains the state with clusters and dynamically predicts the transitions in a network model. In the proposed dynamics-augmented CNM (dCNM) the prediction error is reduced with trajectory-based clustering using the same number of centroids. The dCNM is first exemplified for the Lorenz system and then demonstrated for the three-dimensional sphere wake featuring periodic, quasi-periodic and chaotic flow regimes. For both plants, the dCNM significantly outperforms the CNM in resolving the multi-frequency and multiscale dynamics. This increased prediction accuracy is obtained by stratification of the state space aligned with the direction of the trajectories. Thus, the dCNM has numerous potential applications to a large spectrum of shear flows, even for complex dynamics.
Assessing Autonomy, Competence, and Relatedness Briefly
Authors: Martela Frank , Ryan Richard M.
Published: July 2024

Abstract: The satisfaction of the psychological needs for autonomy, competence, and relatedness have been established as central components of human well-being, predictive of various positive behavioral and psychological outcomes. However, in many contexts, they need to be assessed very briefly, sometimes with just one item. Recent research has shown that well-designed single-item scales of relatively unidimensional constructs can perform surprisingly well. Accordingly, this project aimed to create and validate single-item scales for the three needs. In Study 1 ( n = 353, UK), we generated new items based on careful examination of the construct definitions and tested them alongside established multi-item need satisfaction scales. In Study 2 ( n = 335, US), we replicated these results using a shorter time span (need satisfaction yesterday). Study 3 ( n = 327, UK) compared the performance to a few other brief need satisfaction scales. In all studies, the new single items loaded excellently on respective longer scales and correlated with criterion variables at near identical levels as the longer scales. Given that the performance of the single-item scales was comparable to the established multi-item scales, they are recommended as valid and useful measures of need satisfaction for research context requiring very brief measures.
Role of Salinity Barrier Layers and Westerly Wind Anomalies on Atlantic Niño Events
Authors: Ma Xiao , Liu Hailong
Published: July 2024

Previous studies have confirmed the diverse spatiotemporal characteristics of Atlantic Niño events. Our research further reveals the crucial preparatory role of equatorial western Atlantic barrier layers (BL) and the triggering effect of westerly wind bursts (WWB) on different varieties of Atlantic Niño. Strong easterly winds typically facilitate the formation of thick BL by deepening isothermal layer depth in the western Atlantic through horizontal transport. The existence of BL accumulates the necessary heat for the onset of Atlantic Niño. Additionally, the timing of BL occurrences, the presence of easterly wind anomalies preceding WWB, and the duration of westerly wind anomalies jointly contribute to Atlantic Niño diversity. Persistent westerly wind anomalies following strong easterly winds often lead to Atlantic Niño events lasting over 6 months, while short‐lived events occur when westerly wind anomalies cease shortly after their onset.
Quantifying the Diversity of an Atmospheric Aerosol Population in an Arctic Oil Field on a Single‐Particle Level
Authors: Wu J. , Liu J. , Gunsch M. J. , Mirrielees J. A. , Moffett C. E. , Zhang Q. , Sheesley R. J. , Pratt K. A.
Published: July 2024

As the Arctic rapidly warms, sea ice extent is decreasing and oil and gas extraction activities are expanding. Local combustion emissions affect the Arctic atmospheric aerosol chemical mixing state (the distribution of chemical species across the aerosol population), which impacts climate‐relevant properties. Bulk and single‐particle measurements of submicron aerosols were conducted at Oliktok Point, Alaska within the North Slope of Alaska oil fields. In this work, we quantify aerosol diversity using online single‐particle mass spectrometry data (32,880 individual particles), offline single‐particle microscopy data (20,912 individual particles), and online bulk aerosol mass spectrometry and aethalometer data. This method was used to derive individual particle mass fractions for both refractory and non‐refractory material within distinct particle types. Single‐particle, average single‐particle, and bulk population diversities (Di, Dα, Dγ, respectively) and mixing state indices (χ) were calculated for the data set. Calculated Di values were generally low (2.2 ± 0.6), as individual particle masses were dominated by a few chemical species of interest. Aged aerosol particles (those internally mixed with nitrate and/or sulfate) exhibited higher Di values (>3) compared to recently emitted (fresh) aerosol particles. During oil field plume periods, Dα values approached three due to the abundance of diesel combustion particles, which were rich in sulfate, black carbon, and organic aerosol. Overall, the submicron aerosol population within the Arctic oil fields was found to be relatively externally mixed (χ < 50%), due to the constant local emissions within oil fields combining with background aerosol and locally emitted sea spray aerosol at the coastal site.
Characterizing Mesoscale Cellular Convection in Marine Cold Air Outbreaks With a Machine Learning Approach
Authors: Lackner Christian P. , Geerts Bart , Juliano Timothy W. , Kosovic Branko , Xue Lulin
Published: July 2024

During marine cold‐air outbreaks (MCAOs), when cold polar air moves over warmer ocean, a well‐recognized cloud pattern develops, with open or closed mesoscale cellular convection (MCC) at larger fetch over open water. The Cold‐Air Outbreaks in the Marine Boundary Layer Experiment provided a comprehensive set of ground‐based in situ and remote sensing observations of MCAOs at a coastal location in northern Norway. MCAO periods that unambiguously exhibit open or closed MCC are determined. Individual cells observed with a profiling Ka‐band radar are identified using a watershed segmentation method. Using self‐organizing maps (SOMs), these cells are then objectively classified based on the variability in their vertical structure. The SOM nodes contain some information about the location of the cell transect relative to the center of the MCC. This adds classification noise, requiring numerous cell transects to isolate cell dynamical information. The SOM‐based classification shows that comparatively intense convection occurs only in open MCC. This convection undergoes an apparent lifecycle. Developing cells are associated with stronger updrafts, large spectrum width, larger amounts of liquid water, lower surface precipitation rates, and lower cloud tops than mature and weakening cells. The weakening of these cells is associated with the development of precipitation‐induced cold pools. The SOM classification also reveals less intense convection, with a similar lifecycle. More stratiform vertical cloud structures with weak vertical motions are common during closed MCC periods and are separated into precipitating and non‐precipitating stratiform cores. Convection is observed only occasionally in the closed MCC environment.
HIF-1 inactivation empowers HIF-2 to drive hypoxia adaptation in aggressive forms of medulloblastoma
Authors: Contenti J. , Guo Y. , Larcher M. , Mirabal-Ortega L. , Rouleau M. , Irondelle M. , Tiroille V. , Mazzu A. , Duranton-Tanneur V. , Pedeutour F. , Ben-Sahra I. , Lago C. , Leva G. , Tiberi L. , Robert G. , Pouponnot C. , Bost F. , Mazure N. M.
Published: July 2024

Medulloblastoma (MB) is the most prevalent brain cancer in children. Four subgroups of MB have been identified; of these, Group 3 is the most metastatic. Its genetics and biology remain less clear than the other groups, and it has a poor prognosis and few effective treatments available. Tumor hypoxia and the resulting metabolism are known to be important in the growth and survival of tumors but, to date, have been only minimally explored in MB. Here we show that Group 3 MB tumors do not depend on the canonical transcription factor hypoxia-inducible factor-1α (HIF-1α) to mount an adaptive response to hypoxia. We discovered that HIF-1α is rendered inactive either through post-translational methylation, preventing its nuclear localization specifically in Group 3 MB, or by a low expression that prevents modulation of HIF-target genes. Strikingly, we found that HIF-2 takes over the role of HIF-1 in the nucleus and promotes the activation of hypoxia-dependent anabolic pathways. The exclusion of HIF-1 from the nucleus in Group 3 MB cells enhances the reliance on HIF-2’s transcriptional role, making it a viable target for potential anticancer strategies. By combining pharmacological inhibition of HIF-2α with the use of metformin, a mitochondrial complex I inhibitor to block respiration, we effectively induced Group 3 MB cell death, surpassing the effectiveness observed in Non-Group 3 MB cells. Overall, the unique dependence of MB cells, but not normal cells, on HIF-2-mediated anabolic metabolism presents an appealing therapeutic opportunity for treating Group 3 MB patients with minimal toxicity.
Exploring high corrosion-resistant refractory high-entropy alloy via a combined experimental and simulation study
Authors: Zhao Xinpeng , Huang Haiyou , Su Yanjing , Qiao Lijie , Yan Yu
Published: July 2024

Refractory high-entropy alloys (HEAs) have attracted considerable attention due to their stable phase structure and excellent high-temperature properties. In this work, we performed first-principles calculations, coupled with experiments, to explore HEAs with high corrosion resistance. The results revealed that TiNbTa-based HEAs exhibited a lower tendency for corrosion. However, the appearance of local chemical fluctuations (LCFs) increased the corrosion tendency of TiNbTa-based HEAs. Comprehensive SHapley Additive exPlanations analyses uncovered that in a sample with configurational LCFs, the atomic order near the surface was altered. Therefore, corrosion behavior was affected. Based on experiments, the annealed samples exhibited typical chemical segregation and declined corrosion resistance.
Iron-coated Komodo dragon teeth and the complex dental enamel of carnivorous reptiles
Authors: LeBlanc Aaron R. H. , Morrell Alexander P. , Sirovica Slobodan , Al-Jawad Maisoon , Labonte David , D’Amore Domenic C. , Clemente Christofer , Wang Siyang , Giuliani Finn , McGilvery Catriona M. , Pittman Michael , Kaye Thomas G. , Stevenson Colin , Capon Joe , Tapley Benjamin , Spiro Simon , Addison Owen
Published: July 2024

Komodo dragons (Varanus komodoensis) are the largest extant predatory lizards and their ziphodont (serrated, curved and blade-shaped) teeth make them valuable analogues for studying tooth structure, function and comparing with extinct ziphodont taxa, such as theropod dinosaurs. Like other ziphodont reptiles, V. komodoensis teeth possess only a thin coating of enamel that is nevertheless able to cope with the demands of their puncture–pull feeding. Using advanced chemical and structural imaging, we reveal that V. komodoensis teeth possess a unique adaptation for maintaining their cutting edges: orange, iron-enriched coatings on their tooth serrations and tips. Comparisons with other extant varanids and crocodylians revealed that iron sequestration is probably widespread in reptile enamels but it is most striking in V. komodoensis and closely related ziphodont species, suggesting a crucial role in supporting serrated teeth. Unfortunately, fossilization confounds our ability to consistently detect similar iron coatings in fossil teeth, including those of ziphodont dinosaurs. However, unlike V. komodoensis, some theropods possessed specialized enamel along their tooth serrations, resembling the wavy enamel found in herbivorous hadrosaurid dinosaurs. These discoveries illustrate unexpected and disparate specializations for maintaining ziphodont teeth in predatory reptiles.
AI models collapse when trained on recursively generated data
Authors: Shumailov Ilia , Shumaylov Zakhar , Zhao Yiren , Papernot Nicolas , Anderson Ross , Gal Yarin
Published: July 2024

Stable diffusion revolutionized image creation from descriptive text. GPT-2 (ref. 1), GPT-3(.5) (ref. 2) and GPT-4 (ref. 3) demonstrated high performance across a variety of language tasks. ChatGPT introduced such language models to the public. It is now clear that generative artificial intelligence (AI) such as large language models (LLMs) is here to stay and will substantially change the ecosystem of online text and images. Here we consider what may happen to GPT-{n} once LLMs contribute much of the text found online. We find that indiscriminate use of model-generated content in training causes irreversible defects in the resulting models, in which tails of the original content distribution disappear. We refer to this effect as ‘model collapse’ and show that it can occur in LLMs as well as in variational autoencoders (VAEs) and Gaussian mixture models (GMMs). We build theoretical intuition behind the phenomenon and portray its ubiquity among all learned generative models. We demonstrate that it must be taken seriously if we are to sustain the benefits of training from large-scale data scraped from the web. Indeed, the value of data collected about genuine human interactions with systems will be increasingly valuable in the presence of LLM-generated content in data crawled from the Internet.
Global atmospheric methane uptake by upland tree woody surfaces
Authors: Gauci Vincent , Pangala Sunitha Rao , Shenkin Alexander , Barba Josep , Bastviken David , Figueiredo Viviane , Gomez Carla , Enrich-Prast Alex , Sayer Emma , Stauffer Tainá , Welch Bertie , Elias Dafydd , McNamara Niall , Allen Myles , Malhi Yadvinder
Published: July 2024

Methane is an important greenhouse gas1, but the role of trees in the methane budget remains uncertain2. Although it has been shown that wetland and some upland trees can emit soil-derived methane at the stem base3,4, it has also been suggested that upland trees can serve as a net sink for atmospheric methane5,6. Here we examine in situ woody surface methane exchange of upland tropical, temperate and boreal forest trees. We find that methane uptake on woody surfaces, in particular at and above about 2 m above the forest floor, can dominate the net ecosystem contribution of trees, resulting in a net tree methane sink. Stable carbon isotope measurement of methane in woody surface chamber air and process-level investigations on extracted wood cores are consistent with methanotrophy, suggesting a microbially mediated drawdown of methane on and in tree woody surfaces and tissues. By applying terrestrial laser scanning-derived allometry to quantify global forest tree woody surface area, a preliminary first estimate suggests that trees may contribute 24.6–49.9 Tg of atmospheric methane uptake globally. Our findings indicate that the climate benefits of tropical and temperate forest protection and reforestation may be greater than previously assumed.
Single-cell multiregion dissection of Alzheimer’s disease
Authors: Mathys Hansruedi , Boix Carles A. , Akay Leyla Anne , Xia Ziting , Davila-Velderrain Jose , Ng Ayesha P. , Jiang Xueqiao , Abdelhady Ghada , Galani Kyriaki , Mantero Julio , Band Neil , James Benjamin T. , Babu Sudhagar , Galiana-Melendez Fabiola , Louderback Kate , Prokopenko Dmitry , Tanzi Rudolph E. , Bennett David A. , Tsai Li-Huei , Kellis Manolis
Published: July 2024

Alzheimer’s disease is the leading cause of dementia worldwide, but the cellular pathways that underlie its pathological progression across brain regions remain poorly understood1–3. Here we report a single-cell transcriptomic atlas of six different brain regions in the aged human brain, covering 1.3 million cells from 283 post-mortem human brain samples across 48 individuals with and without Alzheimer’s disease. We identify 76 cell types, including region-specific subtypes of astrocytes and excitatory neurons and an inhibitory interneuron population unique to the thalamus and distinct from canonical inhibitory subclasses. We identify vulnerable populations of excitatory and inhibitory neurons that are depleted in specific brain regions in Alzheimer’s disease, and provide evidence that the Reelin signalling pathway is involved in modulating the vulnerability of these neurons. We develop a scalable method for discovering gene modules, which we use to identify cell-type-specific and region-specific modules that are altered in Alzheimer’s disease and to annotate transcriptomic differences associated with diverse pathological variables. We identify an astrocyte program that is associated with cognitive resilience to Alzheimer’s disease pathology, tying choline metabolism and polyamine biosynthesis in astrocytes to preserved cognitive function late in life. Together, our study develops a regional atlas of the ageing human brain and provides insights into cellular vulnerability, response and resilience to Alzheimer’s disease pathology.
Cryo-EM architecture of a near-native stretch-sensitive membrane microdomain
Authors: Kefauver Jennifer M. , Hakala Markku , Zou Luoming , Alba Josephine , Espadas Javier , Tettamanti Maria G. , Gajić Jelena , Gabus Caroline , Campomanes Pablo , Estrozi Leandro F. , Sen Nesli E. , Vanni Stefano , Roux Aurélien , Desfosses Ambroise , Loewith Robbie
Published: July 2024

Biological membranes are partitioned into functional zones termed membrane microdomains, which contain specific lipids and proteins1–3. The composition and organization of membrane microdomains remain controversial because few techniques are available that allow the visualization of lipids in situ without disrupting their native behaviour3,4. The yeast eisosome, composed of the BAR-domain proteins Pil1 and Lsp1 (hereafter, Pil1/Lsp1), scaffolds a membrane compartment that senses and responds to mechanical stress by flattening and releasing sequestered factors5–9. Here we isolated near-native eisosomes as helical tubules made up of a lattice of Pil1/Lsp1 bound to plasma membrane lipids, and solved their structures by helical reconstruction. Our structures reveal a striking organization of membrane lipids, and, using in vitro reconstitutions and molecular dynamics simulations, we confirmed the positioning of individual PI(4,5)P2, phosphatidylserine and sterol molecules sequestered beneath the Pil1/Lsp1 coat. Three-dimensional variability analysis of the native-source eisosomes revealed a dynamic stretching of the Pil1/Lsp1 lattice that affects the sequestration of these lipids. Collectively, our results support a mechanism in which stretching of the Pil1/Lsp1 lattice liberates lipids that would otherwise be anchored by the Pil1/Lsp1 coat, and thus provide mechanistic insight into how eisosome BAR-domain proteins create a mechanosensitive membrane microdomain.
Shifts in receptors during submergence of an encephalitic arbovirus
Authors: Li Wanyu , Plante Jessica A. , Lin ChieYu , Basu Himanish , Plung Jesse S. , Fan Xiaoyi , Boeckers Joshua M. , Oros Jessica , Buck Tierra K. , Anekal Praju V. , Hanson Wesley A. , Varnum Haley , Wells Adrienne , Mann Colin J. , Tjang Laurentia V. , Yang Pan , Reyna Rachel A. , Mitchell Brooke M. , Shinde Divya P. , Walker Jordyn L. , Choi So Yoen , Brusic Vesna , Llopis Paula Montero , Weaver Scott C. , Umemori Hisashi , Chiu Isaac M. , Plante Kenneth S. , Abraham Jonathan
Published: July 2024

Western equine encephalitis virus (WEEV) is an arthropod-borne virus (arbovirus) that frequently caused major outbreaks of encephalitis in humans and horses in the early twentieth century, but the frequency of outbreaks has since decreased markedly, and strains of this alphavirus isolated in the past two decades are less virulent in mammals than strains isolated in the 1930s and 1940s1–3. The basis for this phenotypic change in WEEV strains and coincident decrease in epizootic activity (known as viral submergence3) is unclear, as is the possibility of re-emergence of highly virulent strains. Here we identify protocadherin 10 (PCDH10) as a cellular receptor for WEEV. We show that multiple highly virulent ancestral WEEV strains isolated in the 1930s and 1940s, in addition to binding human PCDH10, could also bind very low-density lipoprotein receptor (VLDLR) and apolipoprotein E receptor 2 (ApoER2), which are recognized by another encephalitic alphavirus as receptors4. However, whereas most of the WEEV strains that we examined bind to PCDH10, a contemporary strain has lost the ability to recognize mammalian PCDH10 while retaining the ability to bind avian receptors, suggesting WEEV adaptation to a main reservoir host during enzootic circulation. PCDH10 supports WEEV E2–E1 glycoprotein-mediated infection of primary mouse cortical neurons, and administration of a soluble form of PCDH10 protects mice from lethal WEEV challenge. Our results have implications for the development of medical countermeasures and for risk assessment for re-emerging WEEV strains.