bluuebunny/crossref_metadata_2025 huggingface dataset:
Whole genome sequencing reveals stepping‐stone dispersal buffered against founder effects in a range expanding seabird
Authors: Herman Rachael W. , Clucas Gemma , Younger Jane , Bates John , Robinson Bryce , Reddy Sushma , Stepanuk Julia , O'Brien Katie , Veeramah Krishna , Lynch Heather J.
Published: February 2024

Many species are shifting their ranges in response to climate‐driven environmental changes, particularly in high‐latitude regions. However, the patterns of dispersal and colonization during range shifting events are not always clear. Understanding how populations are connected through space and time can reveal how species navigate a changing environment. Here, we present a fine‐scale population genomics study of gentoo penguins (Pygoscelis papua), a presumed site‐faithful colonial nesting species that has increased in population size and expanded its range south along the Western Antarctic Peninsula. Using whole genome sequencing, we analysed 129 gentoo penguin individuals across 12 colonies located at or near the southern range edge. Through a detailed examination of fine‐scale population structure, admixture, and population divergence, we inferred that gentoo penguins historically dispersed rapidly in a stepping‐stone pattern from the South Shetland Islands leading to the colonization of Anvers Island, and then the adjacent mainland Western Antarctica Peninsula. Recent southward expansion along the Western Antarctic Peninsula also followed a stepping‐stone dispersal pattern coupled with limited post‐divergence gene flow from colonies on Anvers Island. Genetic diversity appeared to be maintained across colonies during the historical dispersal process, and range‐edge populations are still growing. This suggests large numbers of migrants may provide a buffer against founder effects at the beginning of colonization events to maintain genetic diversity similar to that of the source populations before migration ceases post‐divergence. These results coupled with a continued increase in effective population size since approximately 500–800 years ago distinguish gentoo penguins as a robust species that is highly adaptable and resilient to changing climate.
SNAC1‐OsERF103‐OsSDG705 module mediates drought response in rice
Authors: Yang Lijia , Xu Liang , Guo Jiazhuo , Li Aipeng , Qi Haoyue , Wang Jiaxuan , Song Shiyong
Published: February 2024

Drought stress profoundly hampers both plant growth and crop yield. To combat this, plants have evolved intricate transcriptional regulation mechanisms as a pivotal strategy.

Through a genetic screening with rice genome‐scale mutagenesis pool under drought stress, we identified an APETALA2/Ethylene Responsive Factor, namely OsERF103, positively responds to drought tolerance in rice. Combining chromatin immunoprecipitation sequencing and RNA sequencing analyses, we pinpointed c. 1000 genes directly influenced by OsERF103.

Further results revealed that OsERF103 interacts with Stress‐responsive NAC1 (SNAC1), a positive regulator of drought tolerance in rice, to synergistically regulate the expression of key drought‐related genes, such as OsbZIP23. Moreover, we found that OsERF103 recruits a Su(var)3‐9,enhancer of zeste and trithorax‐domain group protein 705, which encodes a histone 3 lysine 4 (H3K4)‐specific methyltransferase to specifically affect the deposition of H3K4me3 at loci like OsbZIP23 and other genes linked to dehydration responses. Additionally, the natural alleles of OsERF103 are selected during the domestication of both indica and japonica rice varieties and exhibit significant geographic distribution.

Collectively, our findings have unfurled a comprehensive mechanistic framework underlying the OsERF103‐mediated cascade regulation of drought response. This discovery not only enhances our understanding of drought signaling but also presents a promising avenue for the genetic improvement of drought‐tolerant rice cultivars.
Detection of intact polyene pigments in Miocene gastropod shells
Authors: Wolkenstein Klaus , Schmidt Burkhard C. , Harzhauser Mathias
Published: February 2024

Polyene pigments represent a major class of pigments in present‐day organisms. Their occurrence in fossils has been frequently discussed, but to date no spectroscopic evidence has been found. Here, we use in situ Raman spectroscopy to examine the chemistry of exceptionally well‐preserved gastropod shells with colour preservation from the Middle Miocene of the Vienna Basin (Austria, Hungary). Raman signals indicative of the presence of intact (i.e. non‐hydrogenated) polyene pigments were obtained from fossil shells with reddish colour patterns, thus revealing the first record of intact polyenes in fossils. The observed Raman values are in good agreement with those of unmethylated (non‐carotenoid) polyenes. Fossil polyene pigments were detected in representatives of the superfamily Cerithioidea, but not in representatives of other gastropod families with colour preservation found at the same localities, demonstrating that the occurrence of polyene pigments is taxon‐specific. Our results show that Raman spectroscopy represents a valuable tool for the non‐destructive screening of rare fossils with colour preservation for the occurrence of polyene pigments.
Infantile anogenital digitate keratoses
Authors: Savard Sophie‐Anne , Powell Julie , Marcoux Danielle , Coulombe Jérôme
Published: February 2024

Infantile anogenital digitate keratoses (IADK) represent a distinct and under‐recognized pediatric condition of the perianal area of infants, significantly more frequent in males than females. The average age of onset is 3.2 months, and it is self‐remitting by 2 years of age. Perianal spiny keratoses resistant to usual topical therapies are the hallmark of IADK. We present a series of three cases of IADK seen at the dermatology clinic of the CHU Sainte‐Justine to raise awareness on this pediatric condition, and to prevent invasive workup.
Mapping the intersection of social determinants of health, postpartum visit attendance, and pregnancy‐related deaths: A scoping review
Authors: Ware Katilya S. , Thompson Claire , Renfroe Karol , Grabowsky Adelia , Onuorah Peace O. , Williams Courtney H.
Published: February 2024

Background

Maternal health outcomes in the United States raises concern due to elevated rates of pregnancy‐related deaths compared to other developed and underdeveloped countries. This scoping review explores relationships between social determinants of health (SDOH), postpartum visit attendance, and pregnancy‐related deaths.

Methods

Utilizing the Arksey and O'Malley framework and PRISMA‐Scr guidelines, a systematic review was conducted to identify pertinent literature.

Results

Eight studies were analyzed, providing insights into SDOH, postpartum visits, and pregnancy‐related deaths. The findings highlight healthcare access/quality, economic stability, education, and social/community context as influential in postpartum care utilization. Health insurance emerges a key factor for postpartum attendance.  In addition, disparities in geographic access to maternity care services were linked to pregnancy‐related deaths. Social contextual factors, such as marital status and social support, exhibited varying associations with postpartum visit attendance.

Conclusion

While the analyzed studies provided valuable insight, there remains a gap in the literature examining all three key elements: SDOH, postpartum visit attendance, and pregnancy‐related deaths. In conclusion, this scoping review highlights the vital role of addressing social determinants in improving maternal health outcomes.  Further research is necessary to better inform interventions to reduce pregnancy‐related deaths.
Natural resource fund governance and the institutionalization of rent seeking in Nigeria's oil sector
Authors: Asiegbu Martin F. , Ikeanyibe Okey Marcellus , Abang Pius Otu , Nwosu Okwudili Chukwuma , Ugwu Chuka Eugene
Published: February 2024

The concept of resource curse is widely accepted in the extant literature. However, the burden of proof remains high as some resource‐rich countries experience rapid economic growth. This study examines how Nigeria's strategy for governance and management of revenue proceeds from petroleum resources has helped sustain rent‐seeking behavior, the resource curse phenomenon, and under‐development of the country. Using the theory of new institutionalism and a process‐tracing method, the article argues that political and historical dynamics in establishing legislation for governance and management of oil and gas revenues engendered path‐dependent rent‐seeking practices sustained by selfish political elites. The resource curse is not universal or inevitable in resource‐rich countries, but largely a product of institutionalization and sustenance of initial unhealthy practices. We recommend that recognizing the need for savings, stabilization, and investment, and setting clear fiscal rules to check excessive political discretion will reduce rent seeking and the resource curse in Nigeria and elsewhere.

Related Articles

Ali, Hamid E., and Shahjahan Bhuiyan. 2022. “Governance, Natural Resources Rent, and Infrastructure Development: Evidence from the Middle East and North Africa.” Politics & Policy 50(2): 408–40. https://doi.org/10.1111/polp.12451.

Ikeanyibe, Okechukwu M. 2018. “Bureaucratic Politics and the Implementation of Liberalization Reforms in Nigeria: A Study of the Unbundling and Reorganization of the Nigerian National Petroleum Corporation.” Politics & Policy 46(2): 263–94. https://doi.org/10.1111/polp.12249.

Mähler, Annegret. 2011. “Oil in Venezuela: Triggering Conflicts or Ensuring Stability? A Historical Comparative Analysis.” Politics & Policy 39(4): 583–611. https://doi.org/10.1111/j.1747‐1346.2011.00305.x.
Nature as a sentient being: Can rivers be legal persons?
Authors: Edirisinghe Asanka , Suchet‐Pearson Sandie
Published: February 2024

The concept of ‘legal personhood and rights of rivers’ has developed as an alternative to anthropocentric legal frameworks that focus only on the instrumental values of rivers. Obtaining legal personhood marks a key milestone in legal recognition that could provide for the protection of rivers for more than the instrumental values that they hold. However, who could be considered legal persons is the subject of widespread debate in Western jurisprudence. Legalists hold that anything and anyone can be a legal person while Realists believe that a legal person is defined by certain attributes held only by certain categories of persons. One of the main arguments against the personhood of rivers raised by Realists is that rivers are not sentient beings and, consequently, they are incapable of holding the status of a legal person. The idea that nature is not a sentient being is mainly a Western construct. This research analyses the theory of legal personhood to determine whether rivers can and should be legal persons. It challenges the Realist claim that rivers cannot be legal persons because they lack sentience, drawing on Indigenous Vedda ontologies in Sri Lanka and Aboriginal worldviews from the continent now called Australia. The authors argue that a pluralistic approach to legal personhood is crucial in recognising and valuing our hyperconnected world, preventing categorisation, homogenisation and colonisation of ontologies and addressing sustainability challenges surrounding rivers. The research contributes to the existing scholarly work by defending the concept of legal personhood for rivers within a more pluralistic legal philosophy and addressing one of its major criticisms.
Characterization of the novel HLA‐A*32:177 allele by sequencing‐based typing
Authors: Blandin Lucie , Ralazamahaleo Mamy , Cargou Marine , Rouzaire Paul , Lemal Richard
Published: February 2024

HLA‐A*32:177 differs from HLA‐A*32:01:01:01 by one nucleotide substitution in codon ‐16 in exon 1.
The effect of virtual reality technology in exercise and lung function of patients with chronic obstructive pulmonary disease: A systematic review and meta‐analysis
Authors: Liu Yaxin , Du Qiufeng , Jiang Yunlan
Published: February 2024

Background

Chronic obstructive pulmonary disease (COPD) is a serious chronic disease worldwide, with significant negative impacts on the quality of life, family economic burden, and social healthcare burden of patients.

Aims

The aim of this study was to explore the effects of virtual reality technology on exercise function and lung function in COPD patients.

Methods

A meta‐analysis of randomized controlled trials was utilized. PubMed, Embase, Cochrane Library, Web of Science, PsycINFO, CINAHL, Medline, Scopus, China National Knowledge Infrastructure (CNKI), Wanfang Database, Weipu Database (VIP), and Chinese Biomedical Database (CBM) were systematically searched. We included randomized controlled trials published from the establishment of the database to August 10, 2022, on virtual reality technology in COPD patients. Literature retrieval and screening was carried out independently by two reviewers to obtain literature that met our inclusion and exclusion criteria and to extract relevant data. Two reviewers assessed the risk of bias in the included literature. A meta‐analysis was performed using Revman 5.4 Software.

Results

A total of 10 randomized controlled trials with 539 participants were included. The results showed that virtual reality technology significantly improved the lung function of COPD patients, such as forced expiratory volume (FEV1; MD = 7.29, 95% CI [4.34, 10.24], p < .01) and forced expiratory volume/forced vital capacity (FEV1/FVC; MD = 6.71, 95% CI [4.72, 8.71], p < .01). The combined intervention with different virtual reality technology had different effects on motor function. Compared with endurance training (ET) alone, virtual reality technology combined with ET had no significant effect on the 6‐minute walk test (6WMT) in COPD patients (p > .05). Compared with pulmonary rehabilitation (PR) alone, virtual reality technology combined with PR was more effective in increasing 6WMT in COPD patients (MD = 30.80, 95% CI [10.85, 50.74], p < .01).

Linking Evidence to Action

Virtual reality technology can help to improve lung function in COPD patients, and virtual reality combined with PR can improve exercise tolerance in COPD patients. However, due to the limited number of included studies, large‐sample, multicenter, high‐quality randomized controlled trial studies are needed to provide clear evidence.
LSTM Neural Networks Using the SMOTE Algorithm for Wind Turbine Fault Prediction
Authors: Oliveira Schmidt Júlio , França Aires Lucas , Hubner Guilherme Ricardo , Pinheiro Humberto , Tello Gamarra Daniel Fernando
Published: February 2024

This work proposes a method using a long short-term memory neural network as a diagnostic tool to detect wind turbine rotor mass imbalance. The method uses the synthetic minority oversampling technique for data augmentation in an unbalanced dataset. For this purpose, a 1.5 MW three-bladed wind turbine model was simulated at Turbsim, FAST, and Matlab Simulink to generate rotor speed data for different scenarios, simulating different wind speeds and creating a mass imbalance by changing the density of the blades in the software. Features extraction and power spectral density were also used to improve the Neural Network results. The results were compared to nine different classifiers with four different combinations of datasets and demonstrated that the technique is promising for mass imbalance detection.
Design and Prototype a Stair-Climbing Wheelchair
Authors: Honarmandi Peyman , Peters Emily , Tang NokTing
Published: February 2024

The disabled usually utilize wheelchairs for their daily mobility and locomotion. These motorized vehicles can travel on relatively flat surfaces or tracks without any problems, but moving up and down the stairs is always a challenge for most commercial wheelchairs. In other words, a person with a disability cannot go anywhere inside a multistory building, shopping store, subway, etc. if they are not built according to accessibility codes. A versatile wheelchair with the ability to negotiate stairs not only improves the daily lives of people with disability, but it can also save their lives in the event of an emergency which requiring immediate evacuation of a building. This article proposes two novel designs to facilitate the stair-climbing feature for a motorized wheelchair. One of the design concepts is based on a curved-spoke mechanism with transformation capability from a round wheel to a tri-leg mechanism to facilitate the translation mode as well as the stair-climbing mode of a wheelchair. The next design concept is an enhanced tri-wheel mechanism using a combination of a tri-wheel setup and planetary gears, to provide a unique capability for the climbing mechanism. After analysis and considering the pros and cons of each design concept, the tri-wheel planetary mechanism has been selected for making a scaled-down model and testing the transmission system on the stairs. The scaled-down prototype can successfully move up or down the stairs in the climbing mode and travel on flat or inclined surfaces in the translation mode.
Experimental Validation of Hydrazine Reaction Model Through Hypervelocity Impact Tests
Authors: Abdulhamid Hakim , Limido Jérôme , Deconinck Paul , Puillet Christian
Published: February 2024

The impact of space debris on a spacecraft can result in a catastrophic event that not only destroys the structure but can also generate additional debris. The design of any spacecraft requires understanding the potential damage that can be inflicted by such an event. This is the case for hydrazine fuel tanks located outside the spacecraft for which it is important to evaluate the condition leading to its explosion. A previous study [1] aimed at developing numerical methods with IMPETUS Afea Solver® to reproduce the detonation of hydrazine and the associated transfer of the momentum to the structure when a fuel tank is impacted by a space debris simulating projectile.
Simulating Hypervelocity Impacts into Rubble Pile Structuresfor Planetary Defense
Authors: Graninger Dawn , Stickle Angela M. , Owen J. Michael , Syal Megan
Published: February 2024

The Double Asteroid Redirection Test (DART) Mission, NASA’s first planetary defense mission, will be the first fullscale test of a kinetic impactor. In this test, DART will impact into Dimorphos, the secondary of the binary asteroid Didymos, and change its orbit around the primary (Cheng et al. 2018, Rivkin et al. 2021). In preparation for the late September 2022 impact, it is necessary to understand how different aspects of asteroid properties can affect the outcome of the DART impact and quantify those effects. The asteroid rendezvous missions, Hayabusa, Hayabusa2, and Osiris-REx, have given us an unprecedented look at near-Earth asteroids and the diversity of environments that exist on these bodies. Specifically, from the Hayabusa2 and Osiris-REx missions to Ryugu and Bennu, we have seen that some near-Earth asteroids lack significant areas of smooth fine-grained regolith, and are instead are characterized as rubble pile structures made up of larger boulders held together. We know that the deflection efficiency of a kinetic impactor is influenced by the target properties, such as material strength and porosity, with impacts into weaker targets having larger deflection efficiencies. While the prevalence of these rubble pile structures in the broader near-Earth asteroid population is unknown, they could exhibit large variations in material strength on a single body (e.g. very weak regolith and strong boulders). Characterizing how these unique topographies with varying material properties could influence a kinetic impactor deflection is necessary to ensure success in a planetary defense scenario.
Use of Statistical Strength Measurements in Computational Fracture Calculations for High Speed Impacts
Authors: Hopson Michael , Scott Christine , Alexander Scott
Published: February 2024

The fracture and fragmentation of materials subjected to high strain rate loading is a relevant topic for explosively driven metals, high velocity impacts and other high stress-rate and strain-rate loading events. Metals possess a microstructure whose details create variations in material properties such as strength. The same material microstructure also produces complex damage mechanisms which may lead to macroscopic failure. Ultimately these variations influence the formation of fragments at the macroscopic level. The spatial scale of the microstructure is on the order of micrometers and is not readily accessible to current computational tools and resources for system level calculations. Rather than explicitly model the microstructure, one can attempt to simulate the effects of material non-homogeneity through the use of a statistical description of mechanical properties, of strength, failure or other relevant state descriptions of the model’s dependent variables. For the current analysis, a statistical variation was applied to the yield stress. This variation was based upon multiple Vickers hardness tests which measure strength on the order of 1 millimeter. This is a length scale which is consistent with the calculation spatial discretization. Loosely coupled Euler-Lagrange calculations were performed of an experiment where a high speed projectile was used to fracture stainless steel rings. A Weibull distribution of yield stress was applied to the stainless steel rings to simulate the heterogeneous nature of the steel. Calculation results were compared to experimental data to assess the validity of this technical approach as a predictive capability for fracture and fragmentation.
Fluid-Solid Coupled Simulation of Hypervelocity Impact and Plasma Formation
Authors: Islam Shafquat T. , Ma Wentao , Michopoulos John G. , Wang Kevin
Published: February 2024

In hypervelocity impact events that occur within a fluid medium, the projectile produces a hypersonic fluid flow during its flight. The violent collision between the projectile and the target leads to the emission of high-energy shock waves that disrupt the initial flow field. The high temperature (e.g., thousands of kelvin) resulting from the collision may also lead to ionization and plasma expansion in the fluid medium. Understanding the fluid dynamics and thermodynamics is important for developing a complete description of a hypervelocity impact event. Previous computational studies have been largely focused on the mechanics and material behaviors within the projectile and the target, while the surrounding fluid is often simplified as a vacuum. In this talk, we will present the development of a new, fluid-solid coupled computational model of hypervelocity impact, and the application of this model to the simulation of copper projectiles impacting on soda lime glass (slg) at velocities between 4 km/s and 8 km/s. the introduction here. All running text, including the introduction, should be right-justified, in two columns, single-spaced, and in Times New Roman size 10 font.
Collisional Particle-In-Cell Investigations of RF Emissions in Hypervelocity Impact Plasmas
Authors: Lau Raymond , Lee Nicolas , Close Sigrid
Published: February 2024

Hypervelocity impact plasmas are formed when projectiles greater than the speed of sound in a material (typically 5-10 km/s) strike an object. The high energy associated with this impact causes vaporization and ionization of both the projectile and the target material, forming a mixture of dust, gas, and plasma, or dusty plasma. During the initial expansion of plasma, the high plasma density leads to highly coupled physics and collisions. For hypervelocity impacts onto spacecraft, the latter stages of expansion into the surrounding vacuum are largely collision-less. It has been observed that under certain conditions, radio frequency (RF) emission is produced as a result of the hypervelocity impact. Currently, no consensus regarding the physical mechanism behind the RF emission has been found. Computational models are beneficial tools to investigate plasma physics. In particular, particle-based kinetic methods such as the particle-in-cell (PIC) model are useful due to their ability to capture kinetic and non-Maxwellian effects of plasmas. Previous computational works have modeled the development of the plasma from initial impact [1] and RF emission associated with the collisionless expansion of plasma into the surrounding vacuum [2]. From the former study, RF emission was produced in plasmas for particles with velocities greater than 14 km/s. This RF emission is associated with the transition of the plasma from partial to full ionization. In the latter study, the RF emission simulated was a higher frequency than detected by experiments. This is hypothesized to be due to the initial conditions of the study, which assume a simple bulk separation of the plasma caused by a difference in ion and electron bulk velocities. The exact dynamics behind the bulk separation is required to be simulated more thoroughly. It is expected that the physics is dominated by the transition of the plasma from a highly collisional regime to a collisionless regime. Thus, this work focuses on the addition of collisional PIC schemes and the influence of external electric fields , simulating more accurate bulk separation physics to better understand the mechanisms behind RF emissions in hypervelocity impact plasmas.
A Dedicated Simulation Chain for Hypervelocity Impacts Effect on Disc, Impact Sensor of the Comet Interceptor/ Esa Mission
Authors: Piccirillo A. M. , Corte V. Della , Ferretti S. , Rotundi A. , Ammannito E. , Bertini I. , Ferraioli G. , Fiscale S. , Inno L. , Longobardo A. , Sindoni G. , Wozniakiewicz P.J. , Sylvest M. , Patel M.
Published: February 2024

Comet Interceptor is an ESA mission, which will be launched in 2029 towards an as-yet-undiscovered dynamically new comet. The Dust Impact Sensor and Counter (DISC), developed by our team, will be mounted on board two of the three foreseen Comet Interceptor spacecrafts, aiming to determine the coma dust features of the target comet. DISC’s sensing plate will be exposed to the cometary dust environment and subjected to Hyper-Velocity Impacts (HVI), due to the high flyby speed (7 – 70 km/s). Laboratory facilities do not allow testing the whole range of impact cases that DISC will undergo during the measurements. To overcome this limitation, we implemented a simulation system with ANSYSTM software and AUTODYNTM hydrocode, able to reproduce a wide range of dust particle impacts. The simulation process involves a hybrid model, which is discretized with both Smooth Particles Hydrodynamic (SPH) and Finite Element methods (FE) and organized in two connected phases. The results we herein illustrate confirm that the simulation system we implemented allows simulating the DISC operative phase in an efficient, fast, and reliable way.
Impact Flash Evaluation of Steel and Aluminum Plates at Varying Angles with Millimeter Sized Impactors
Authors: Shaeffer Matthew , Moreno Justin , Simpson Gary , Ramesh K.T.
Published: February 2024

Significant work has been done on characterizing the flash from hypervelocity impacts for space and defense applications. However, singular small impactor events on the 1 mm scale are difficult to perform and characterize due to challenges in launching them and setting up diagnostics that can capture the small flash. Spurred by interest and funding from Johns Hopkins University Applied Physics Laboratory to look at impact flash with small projectiles on different materials at two angles of impact (45 and 90 degrees), the HyFIRE lab at JHU ran trial experiments to launch 1 mm spheres form a 30-caliber barrel at aluminum and steel plates. Steel sphere launches were performed, and the impact flash was viewed using high speed video from a side perspective as well as broadband photodetectors and a spectrograph from 2 viewing angles. Experiments were done at 45 and 90 degrees impact angles. Variation in the viewing angle and flash magnitudes were seen as well as variation in the material spectra. Tunable spectral equipment was useful in capturing the differences between materials, and future work will be done for magnitude calibration to help with temperature calculations.
SPH and Adaptive FEM/SPH Methods in Debris Cloud Simulation
Authors: Ceri Samet , Khodaei Zahra Sharif
Published: February 2024

The Whipple shielding is the most common way to increase aerostructures safety by preventing main structures from the direct impact of the external threats which is broken into small pieces before reaching the witness plate. The diffusion of fragment pieces forms the debris cloud after the collision. It is necessary to understand debris cloud phenomenon to reduce the potential harmful consequence of the impact. To address this issue, it is important to have a reliable and efficient numerical tool to find the optimum shield design due to the high cost of the physical experiments. In this study, the traditional SPH and Adaptive FEM/SPH methods were compared based on the debris cloud’s feature and validated against the analytical model. Two different FEM/SPH adaptive models were used to understand the effect of the mesh regularity of the corresponding solid element. Results from this study indicate that the FEM/SPH adaptive method has lower computational cost than the traditional SPH method and the mesh regularity of the corresponding solid element is key point of the Adaptive FEM/SPH method. Yet, computational efficiency decreases with the increment in number of the element conversion.
Development of Diffusion Bonded Impactors for Reliable Shock-Reshock Experiments
Authors: Specht Paul E. , Johnson Christopher R. , Arata Edward
Published: February 2024

Diffusion bonding of two immiscible, binary metallic systems, Cu-Ta and Cu-W was employed to make repeatable and predictable dual-layer impactors for shock-reshock experiments. The diffusion bonded impactors were characterized using ultrasonic imaging and optical microscopy to ensure bonding and the absence of excessive Cu grain coarsening. The diffusion bonded impactors were launched via a two-stage gas gun at [100] LiF windows instrumented with multiple interferometry probes spanning nearly the entire impactor area. Consistent interferometry data was obtained from all experiments with no evidence of release prior to recompression, indicating a uniform bond. Comparisons to hydrocode simulations show excellent agreement for all experiments, facilitating easy application of these impactors to future experiments.
Cryogenic Capture of Hypervelocity Impact Ejecta
Authors: Tandy Jon , Spathis Vassilia , Alesbrook Luke
Published: February 2024

The capture of impact ejecta is an important tool for the evaluation of chemical modification caused by hypervelocity impact events. Traditional systems typically employ foils, foams or aerogel to capture fast moving ejecta for elemental analyses. These devices are less appropriate for the examination of more volatile components within impact ejecta and may even cause additional chemical reactions on their surface leading to uncertainties in the subsequent analyses. This is particularly disadvantageous for capture systems onboard spacecraft searching for biologically relevant molecules like amino acids. The preliminary design and testing of a cooled capture plate system utilizing a cryogenic cold finger for incorporation with the University of Kent’s two-stage light gas gun is outlined. Experiments using solid nylon sabots at a range of impact speeds were carried out with the majority of targets composed of a glycine-water ice mixture. A minimum capture plate temperature of -71 °C was achieved with an impact chamber pressure of 0.2 mbar but was observed to be closer to -30 oC during vacuum chamber evacuation using frozen targets due to sublimation of the ice’s surface. Shots at impact speeds greater than 6.3 km s-1 showed effective capture of small concentrations of glycine after derivatization and subsequent GC-MS analysis. The additional detection of glycolic acid within the captured material also suggests the potential for significant chemical modification within impact ejecta, which has important implications for the sampling of solar system plumes and surface material transferred across planetary bodies by hypervelocity impacts.
Momentum Enhancement from 3-CM-Diameter Aluminum Sphere Impacts into Iron and Rock at Over 5 KM/S
Authors: Walker James D. , Chocron Sidney , Grosch Donald J. , Marchi Simone , Alexander Amanda
Published: February 2024

Utilizing a large two-stage light gas gun and a large pendulum assembly, experiments were performed to measure the momentum enhancement (or increase in momentum due to the ejecta) of two ARMCO iron targets, a concrete block target, a target of stones held by concrete, and two large hematite rock targets. As we have shown over the past decade in HVIS papers, the role of impactor size is important, and these tests were performed at as large a scale as possible for us at these speeds, with 3-cm-diameter aluminum spheres. All these impacts save one were around 5 km/s. There is a distinct difference in the amount of momentum enhancement that occurs with ductile metals vs. brittle rocks and this is apparent in these impacts. The momentum enhancement with a relatively brittle aluminum falls in between these two extremes. The target comprised of a collection of stones was performed to provide some insight into the upcoming DART impact. Data at this larger scale is highly desirable, especially given our interest in quantifying momentum enhancement to provide needed information in the event hypervelocity impactors are considered in deflecting celestial bodies such as asteroids or comet nuclei.
Optimizing Performance of Compact Hypervelocity Electrothermal Guns: Electrode Composition and Bore Diameter
Authors: Wilmer Brian L. , Uhlig W. Casey , Berning Paul R. , Coppinger Matthew J.
Published: February 2024

A benchtop electrothermal gun capable of launching mmsized objects has achieved muzzle velocities ranging from 1.0 to over 6 km/s. Experiments and simulations have been performed to elucidate the key parameters which drive overall performance. Smaller bore diameters with smaller, lower mass projectiles resulted in the largest velocity gains while larger caliber barrels produced higher efficiencies.
Degradation trumps mutations in cancer
Authors: Davis R. Eric , Westin Jason R.
Published: February 2024

Redirecting targeted proteins for degradation can overcome acquired drug resistance
Is the world 1.3°C or 1.5°C warmer?
Authors: Voosen Paul
Published: February 2024

Global warming’s uncertainty hinges on old logbooks from merchant ships
The microbiological outcomes of culture-negative blood specimens using 16S rRNA broad-range PCR sequencing: a retrospective study in a Canadian province from 2018 to 2022
Authors: Lieu Anthony , Harrison Luke B. , Harel Josée , Lawandi Alexander , Cheng Matthew P. , Domingo Marc-Christian
Published: February 2024

Broad-range 16S rRNA PCR and sequencing of 1,183 blood specimens from 853 unique patients yielded an interpretable sequence and bacterial identification in 29%, 16S rRNA amplification with uninterpretable sequences in 53%, and no amplification in 18%. This study highlights the potential utility of this technique in identifying fastidious gram-negative and anaerobic bacteria but the frequent recovery of environmental and contaminant organisms argues for its judicious use.

IMPORTANCE

The existing literature focuses on its performance compared to blood cultures in patients with sepsis, leaving a gap in the literature regarding other blood specimens in suspected infectious syndrome across the severity spectrum. We aimed to characterize its microbiological outcomes and provide insight into its potential clinical utility.
Single-cell ATAC sequencing identifies sleepy macrophages during reciprocity of cytokines in
L. major
infection
Authors: Khandibharad Shweta , Singh Shailza
Published: February 2024

The hallmark characteristic of macrophages lies in their inherent plasticity, allowing them to adapt to dynamic microenvironments.
Leishmania
strategically modulates the phenotypic plasticity of macrophages, creating a favorable environment for intracellular survival and persistent infection through regulatory cytokine such as interleukin (IL)-10. Nevertheless, these effector cells can counteract infection by modulating crucial cytokines like IL-12 and key components involved in its production. Using sophisticated tool of single-cell assay for transposase accessible chromatin (ATAC) sequencing, we systematically examined the regulatory axis of IL-10 and IL-12 in a time-dependent manner during
Leishmania major
infection in macrophages Our analysis revealed the cellular heterogeneity post-infection with the regulators of IL-10 and IL-12, unveiling a reciprocal relationship between these cytokines. Notably, our significant findings highlighted the presence of sleepy macrophages and their pivotal role in mediating reciprocity between IL-10 and IL-12. To summarize, the roles of cytokine expression, transcription factors, cell cycle, and epigenetics of host cell machinery were vital in identification of sleepy macrophages, which is a transient state where transcription factors controlled the epigenetic remodeling and expression of genes involved in pro-inflammatory cytokine expression and recruitment of immune cells.

IMPORTANCE

Leishmaniasis is an endemic affecting 99 countries and territories globally, as outlined in the 2022 World Health Organization report. The disease’s severity is compounded by compromised host immune systems, emphasizing the pivotal role of the interplay between parasite and host immune factors in disease regulation. In instances of cutaneous leishmaniasis induced by
L. major
, macrophages function as sentinel cells. Our findings indicate that the plasticity and phenotype of macrophages can be modulated to express a cytokine profile involving IL-10 and IL-12, mediated by the regulation of transcription factors and their target genes post
-L. major
infection in macrophages. Employing sophisticated methodologies such as single-cell ATAC sequencing and computational genomics, we have identified a distinctive subset of macrophages termed “sleepy macrophages.” These macrophages exhibit downregulated housekeeping genes while expressing a unique set of variable features. This data set constitutes a valuable resource for comprehending the intricate host-parasite interplay during
L. major
infection.
New myxobacteria of the
Myxococcaceae
clade produce angiolams with antiparasitic activities
Authors: Walesch Sebastian , Garcia Ronald , Mahmoud Abdelhalim B. , Panter Fabian , Bollenbach Sophie , Mäser Pascal , Kaiser Marcel , Krug Daniel , Müller Rolf
Published: February 2024

In the past century, microbial natural products have proven themselves to be substantial and fruitful sources of anti-infectives. In addition to the well-studied Actinobacteria, understudied bacterial taxa like the Gram-negative myxobacteria have increasingly gained attention in the ongoing search for novel and biologically active natural products. In the course of a regional sampling campaign to source novel myxobacteria, we recently uncovered new myxobacterial strains MCy12716 and MCy12733 belonging to the
Myxococcaceae
clade. Early bioactivity screens of the bacterial extracts revealed the presence of bioactive natural products that were identified as angiolam A and several novel derivatives. Sequencing of the corresponding producer strains allowed the identification of the angiolam biosynthetic gene cluster, which was verified by targeted gene inactivation. Based on bioinformatic analysis of the biosynthetic gene cluster, a concise biosynthesis model was devised to explain angiolam biosynthesis. Importantly, novel angiolam derivatives uncovered in this study named angiolams B, C, and D were found to display promising antiparasitic activities against the malaria pathogen
Plasmodium falciparum
in the 0.3–0.8 µM range.

IMPORTANCE

The COVID-19 pandemic and continuously emerging antimicrobial resistance (AMR) have recently raised awareness about limited treatment options against infectious diseases. However, the shortage of treatment options against protozoal parasitic infections, like malaria, is much more severe, especially for the treatment of so-called neglected tropical diseases. The detection of anti-parasitic bioactivities of angiolams produced by MCy12716 and MCy12733 displays the hidden potential of scarcely studied natural products to have promising biological activities in understudied indications. Furthermore, the improved biological activities of novel angiolam derivatives against
Plasmodium falciparum
and the evaluation of its biosynthesis display the opportunities of the angiolam scaffold on route to treat protozoal parasitic infections as well as possible ways to increase the production of derivatives with improved bioactivities.
Prospective fecal microbiomic biomarkers for chronic wasting disease
Authors: Didier Adam , Bourner Maureen , Kleks Guy , Zolty Avihai , Kumar Brajendra , Nichols Tracy , Durynski Karie , Bender Susan , Gibison Michelle , Murphy Lisa , Ellis Julie C. , Dong Dawei W. , Kashina Anna
Published: February 2024

Chronic wasting disease (CWD) is a naturally occurring prion disease in cervids that has been rapidly proliferating in the United States. Here, we investigated a potential link between CWD infection and gut microbiome by analyzing 50 fecal samples obtained from CWD-positive animals of different sexes from various regions in the USA compared to 50 CWD-negative controls using high throughput sequencing of the 16S ribosomal RNA and targeted metabolomics. Our analysis reveals promising trends in the gut microbiota that could potentially be CWD-dependent, including several bacterial taxa at each rank level, as well as taxa pairs, that can differentiate between CWD-negative and CWD-positive deer. Through machine-learning, these taxa and taxa pairs at each rank level could facilitate identification of around 70% of both the CWD-negative and the CWD-positive samples. Our results provide a potential tool for diagnostics and surveillance of CWD in the wild, as well as conceptual advances in our understanding of the disease.

IMPORTANCE

This is a comprehensive study that tests the connection between the composition of the gut microbiome in deer in response to chronic wasting disease (CWD). We analyzed 50 fecal samples obtained from CWD-positive animals compared to 50 CWD-negative controls to identify CWD-dependent changes in the gut microbiome, matched with the analysis of fecal metabolites. Our results show promising trends suggesting that fecal microbial composition can directly correspond to CWD disease status. These results point to the microbial composition of the feces as a potential tool for diagnostics and surveillance of CWD in the wild, including non-invasive CWD detection in asymptomatic deer and deer habitats, and enable conceptual advances in our understanding of the disease.
A CRISPR/LbCas12a-based method for detection of bacterial fruit blotch pathogens in watermelon
Authors: Wang Zelu , Cheng Wenhui , Dong Zhiyu , Yao Xiamei , Deng Xu , Ou Chun
Published: February 2024

Acidovorax citrulli
is the main pathogen causing bacterial fruit blotch, which seriously threatens the global watermelon industry. At present, rapid, sensitive, and low-cost detection methods are urgently needed. The established CRISPR/LbCas12a visual detection method can specifically detect
A. citrulli
and does not cross-react with other pathogenic bacteria such as
Erwinia tracheiphila
,
Pseudomonas syringae
, and
Xanthomonas campestris
. The sensitivity of this method for genomic DNA detection is as low as 0.7 copies/μL, which is higher than conventional PCR and real-time PCR. In addition, this method only takes 2.5 h from DNA extraction to quantitative detection and does not require complex operation and sample treatment. Additionally, the technique was applied to test real watermelon seed samples for
A. citrulli
, and the results were contrasted with those of real-time fluorescence quantitative PCR and conventional PCR. The high sensitivity and specificity have broad application prospects in the rapid detection of bacterial fruit blotch bacterial pathogens of watermelon.

IMPORTANCE

Bacterial fruit blotch,
Acidovorax citrulli
, is an important seed-borne bacterial disease of watermelon, melon, and other cucurbits. The lack of rapid, sensitive, and reliable pathogen detection methods has hampered research on fruit spot disease prevention and control. Here, we demonstrate the CRISPR/Cas12a system to analyze aspects of the specificity and sensitivity of
A. citrulli
and to test actual watermelon seed samples. The results showed that the CRISPR/Cas12a-based free-amplification method for detecting bacterial fruit blotch pathogens of watermelons was specific for
A. citrulli
target genes and 100-fold more sensitive than conventional PCR with quantitative real-time PCR. This method provides a new technical tool for the detection of
A. citrulli
.
Supplemental Material: Nannofossil imprints across the Paleocene-Eocene thermal maximum
Authors: Slater Sam , al. et
Published: February 2024

Table S1 and Figure S1.  
Atypia detected during breast screening and subsequent development of cancer: observational analysis of the Sloane atypia prospective cohort in England
Authors: Freeman Karoline , Jenkinson David , Clements Karen , Wallis Matthew G , Pinder Sarah E , Provenzano Elena , Stobart Hilary , Stallard Nigel , Kearins Olive , Sharma Nisha , Shaaban Abeer , Kirwan Cliona Clare , Hilton Bridget , Thompson Alastair M , Taylor-Phillips Sian
Published: February 2024

Objective

To explore how the number and type of breast cancers developed after screen detected atypia compare with the anticipated 11.3 cancers detected per 1000 women screened within one three year screening round in the United Kingdom.

Design

Observational analysis of the Sloane atypia prospective cohort in England.

Setting

Atypia diagnoses through the English NHS breast screening programme reported to the Sloane cohort study. This cohort is linked to the English Cancer Registry and the Mortality and Birth Information System for information on subsequent breast cancer and mortality.

Participants

3238 women diagnosed as having epithelial atypia between 1 April 2003 and 30 June 2018.

Main outcome measures

Number and type of invasive breast cancers detected at one, three, and six years after atypia diagnosis by atypia type, age, and year of diagnosis.

Results

There was a fourfold increase in detection of atypia after the introduction of digital mammography between 2010 (n=119) and 2015 (n=502). During 19 088 person years of follow-up after atypia diagnosis (until December 2018), 141 women developed breast cancer. Cumulative incidence of cancer per 1000 women with atypia was 0.95 (95% confidence interval 0.28 to 2.69), 14.2 (10.3 to 19.1), and 45.0 (36.3 to 55.1) at one, three, and six years after atypia diagnosis, respectively. Women with atypia detected more recently have lower rates of subsequent cancers detected within three years (6.0 invasive cancers per 1000 women (95% confidence interval 3.1 to 10.9) in 2013-18
v
24.3 (13.7 to 40.1) in 2003-07, and 24.6 (14.9 to 38.3) in 2008-12). Grade, size, and nodal involvement of subsequent invasive cancers were similar to those of cancers detected in the general screening population, with equal numbers of ipsilateral and contralateral cancers.

Conclusions

Many atypia could represent risk factors rather than precursors of invasive cancer requiring surgery in the short term. Women with atypia detected more recently have lower rates of subsequent cancers detected, which might be associated with changes to mammography and biopsy techniques identifying forms of atypia that are more likely to represent overdiagnosis. Annual mammography in the short term after atypia diagnosis might not be beneficial. More evidence is needed about longer term risks.