bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Automatic Target Detection System for 11,000M-Class Underwater Vehicles
Authors: Kakami Hitoshi , Nakatani Takeshi , Maeda Yosaku , Aso Tatsuya , Shinohara Yusuke
Published: August 2024

An underwater vehicle with a tether cable is called a remotely operated vehicle (ROV), and an operator on the mother ship can observe video images and collect samples in real time. However, when operating in very deep sea, the tether cable becomes extremely long, and its handling is technically difficult.

Against this background, the authors are currently developing a vehicle that can operate at great depths without relying on tether cables. In this case, the vehicle requires a higher degree of autonomy since the operator cannot remotely control the vehicle. As a technology necessary for autonomous sample collection, we have developed a system that automatically detects and tracks targets from camera images.

Machine learning methods are widely used as a means of detecting target objects from camera images. We adopted Detection Transformer (DETR) from among multiple methods as a target detection model. We then created an underwater model by training it with videos of deep-sea creatures and dummy targets recorded by our organization. Since camera images in the underwater environment are different from those on land, we applied data augmentation to add lens distortion and blur during training.

We also compared multiple methods for tracking models for detected objects and implemented the Byte-Track algorithm.

The developed system consists of an underwater camera and an image processing device, each housed in a pressure-resistant container designed to be used at great depths. The underwater camera uses a stereo camera system so that it can detect and track the target and measure its position at the same time. The image processing device was sized to fit in a pressure-resistant container, and hardware capable of image processing using a graphics processing unit (GPU) was selected, and the processing performance was confirmed.

After basic confirmation of the developed system through tank tests, it was installed on an 11,000m-class lander owned by our organization and a demonstration test was conducted at a triple junction (depth of 9,200m). Since the possibility of encountering living things at this depth is low, a dummy target was also attached to the lander to confirm detection. As a result, the system successfully detected and tracked targets in real time. On the other hand, detection performance sometimes deteriorated in certain situations such as hiding behind objects.

In order to improve the issues identified this time, the authors plan to conduct additional learning using newly acquired video data. Through continued testing and evaluation, we plan to install it on 11,000m class vehicles in the future.
A Fast Manoeuvring Calculation to Assess the Optimal Vessel Speed in Shallow Water
Authors: Emmersberger Christian , Krüger Stefan
Published: August 2024

The need of improving the energy demand in ship’s operation is driven by growing regulations regarding shipping emission. Therefore, this paper describes an approach to determine the optimal speed of a ship traveling a route with changing water depths. The power demand of vessels in shallow water is higher than in deep water at the same speed. Regarding the energy consumption, it is profitable to slow down in shallow water and compensate the lost time in deeper water. The presented tool enables to find the optimal speed for every water depth segment of a specific ship route by solving an optimization problem. The aim is to obtain the least energy consumption by retaining the same travel time. The approach is built on a fast and adaptable manoeuvring calculation, which is used to determine the fuel consumption of a ship traveling a specific ship route given by waypoints. The additional power demand due to shallow water calculation is obtained by the Schlichting method. The manoeuvring calculation is based on a body force model, that determines the ship’s motion from all forces acting on the ship. The approach is demonstrated by a specific use case and can results in fuel savings of up to 8% dependent on the reference case.
Two-Dimensional Simulation of the Flow Around a Three-Straight Bladed Vertical-Axis Wind Turbine for Different Pitch Angles
Authors: Satyam S. , Fabregat-Sanjuan A. , Huera-Huarte F. J.
Published: August 2024

This two-dimensional Computational Fluid Dynamics (CFD) study, investigates the effect of blade pitch angle on the performance of a vertical-axis wind turbine (VAWT). The research is focused on the analysis of the variations in blade aerodynamic loads and blade-wake interactions for different blade pitch angles. The CFD model deals with a three-straight-bladed VAWT based on NACA-0015 profiles. The rotor has a diameter of 0.75 m with a chord-to-diameter ratio of 0.16. Blade pitch angles, ranging from 8 degrees toe-in to 6 degrees toe-out, have been investigated using Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations at a fixed diameter-based Reynolds number of 5·105. The results show that modifying the blade pitch angle, impacts the flow around the blades and the blade aerodynamic loads, altering overall turbine performance. Adjusting the blade pitch angle from 0 degrees to 2 degrees toe-out, led to a significant increase (over 6%) in the turbine power coefficient (Cp). However, a further increase in the pitch angle leads to a gradual power coefficient decrease. We show that the results, obtained using a two-dimensional CFD model, allow to describe the main features observed in this type of problems.
Lazy Wave Cables and Risers VIV Response: On the Impact of Buoyancy Modules Aspect Ratios and Arrangement
Authors: Jara-Bravo Cristian , Minguez Matthieu , Cinello Alexandre , Marty Antoine , Rippol Thierry
Published: August 2024

In this paper, the impact of buoyancy modules aspect ratios and arrangement on the VIV response of a power cable or riser is addressed through a dual approach coupling experimental and numerical simulations.

Two sets of experiments are performed in the ‘South France – Ocean Basin’ located in La Seyne-Sur-Mer and operated by Océanide. On the first one, rigid sections of pipe equipped with a single buoyancy module are submitted to a pure harmonic crossflow oscillation with over imposed steady flow conditions. From load measurements on the buoyancy modules themselves, a database of hydrodynamic coefficients for several aspect ratios is obtained. Then, the VIV response of a line installed across the basin and fitted with different buoyancy module arrangements was tracked to investigate the impact of buoyancy module aspect ratio, as well as their arrangement.

The data extracted from the second set of tests is used as a benchmark case to validate the numerical approach via Shear 7. Both the default hydrodynamic data from the software and the hydrodynamic database obtained from the first set of tests are compared.

A weaker power input from the buoyancy modules was found compared to the expected results for an infinite cylinder, as well as a possible modification of vortex shedding frequency (Strouhal number). When focusing on the buoyancy module arrangement, the experimental results emphasize the impact of gap between buoyancy modules on the global cable response. Moreover, this experimental/numerical benchmark provides some insight on the validity of the simplified approach of software as Shear7 for this type of riser or power cable configuration.
Service Life Prediction Method for a Free Spanning Pipeline Undergoing Vortex Induced Vibrations
Authors: Song Qing-Yuan , Liu Jun , Gao Fu-Ping
Published: August 2024

Free spans of a subsea pipeline may undergo vortex-induced vibrations (VIVs) and could be damaged by fatigue failure. The free span length is a key parameter for determining the structural natural frequency, which would correspondingly influence the reduced velocity (Vr) for the VIV responses. The existing flume tests indicated that the VIVs of a near-bed cylinder may be triggered effectively in moderate shear flows. This may imply that the vibration cycles of a free spanning pipeline could be up to ten-millions, and the very-high-cycle fatigue (VHCF) could be encountered during the engineering service. On the basis of the dimensionless vibration amplitude A/D-Vr curve and the recommended S-N curve for the high-strength steel pipelines with cathodic protection under seawater environments, a prediction method is proposed for the service life of a free spanning pipeline undergoing VIVs. A case study is then performed to evaluate the service life (in terms of vibration cycles) of the free-spans with the focus on VHCF. It is indicated that, if the characteristic flow velocity is given, the variation of the service life with the span length is generally nonlinear, which is attributed to being involved in various VIV branches of the A/D-Vr curve.
Probabilistic Analyses of Floating Offshore Marine Drilling Operations Using Active Learning Methods
Authors: Garlid Stian , Ren Chao , Xing Yihan
Published: August 2024

Garlid et al. [1] previously showed that it is feasible to determine marine riser disconnect criteria for a mobile offshore drilling unit (MODU) using the structural reliability analysis (SRA) method. The method was presented through a case study of a notional MODU moored, with static thruster assist, in shallow water and subjected to harsh environments. The case study was performed with a series of simplifications that might introduce unwanted conservatism for the end user, such as co-linear environmental forces and static thruster settings. Further, only ten environmental load cases were used to populate the response surfaces, leading to a relatively coarse response surface grid. Still, many time domain (TD) analyses were needed to populate the response surfaces that describe the relevant short-term response statistics. Although more computationally expensive, the SRA method offers several advantages over the conventional frequency-domain method currently employed in the industry. These advantages include the possibility of considering non-linear effects more accurately when considering extreme responses and the possibility of considering the coupling effects between the different components, such as the MODU and marine riser. Therefore, the SRA method is more accurate, allowing operators to run more efficient marine operations and possibly extending operational windows. In this paper, the authors will develop the SRA method further by utilizing active learning when performing the response surface generation to significantly reduce computational efforts. This paper will use the Kriging model to model the response surface. Stochastic noise in the sampling points is included in the model to avoid potential over-fitting. A significant reduction in analysis effort could make the SRA method closer in performance in terms of computational efforts against the conventional frequency domain, but with the added advantages of a high-fidelity method that can consider full-coupling and non-linear effects.
Determining Submarine Dynamic Cable Stiffness and Fatigue Characteristics Through Physical Testing
Authors: Thies Philipp R. , Georgallis Georgios
Published: August 2024

Offshore wind farms are moving into deeper waters, where fixed foundations are not economically viable, forcing the development of floating wind turbines. Recent global estimates by 4C Offshore expect a total of 14 GW of floating wind turbines to be installed by 2030, with another 40GW installation forecasted up to 2050. This will necessitate the manufacture, installation, and commissioning of thousands of floating wind platforms. Electricity will need to be exported from these installations, and therefore dynamic submarine power cables will be one of the most critical and exposed components, connecting the floating platform to static subsea export cables or floating export / production platforms. Dynamic submarine power cables must now have the ability to support increased loads caused by this move into deeper waters and the movement of the floating vessel or platform. They must also be able to tolerate fatigue associated with load changes that occur during their movement in the water column. The structural characteristics of dynamic power cables are often approximated through numerical modelling, and full-scale cable mechanical testing is essential for accurate measurement of key properties, including axial stiffness and bending stiffness. This paper presents a case study and characteristic results of a mechanical cable test campaign, quantifying cable stiffness and fatigue. The example illustrates the value of mechanical testing to better inform both global hydrodynamic models with cable properties and to better calibrate local finite element analysis tools. The paper is useful for researchers and practitioners concerned with the modelling, design and testing of submarine dynamic power cables. It is also useful for project investors and underwriters to better understand the assurance testing of cables as a critical component.
Dual Shear Gun for Efficient Fluid Mixing and Dispersion: Effect of Design Parameters
Authors: Taghipour Ali , Lund Bjørnar , Yterhus Jan David , Saasen Arild , Ånesbug Geir Olav , Pallin Jan Egil
Published: August 2024

Invert emulsion fluids where water droplets are dispersed in an oil phase are often the preferred choice when drilling through problematic formations such as reactive shales. Bulk volume of OBM is typically leased and mixed offsite and transported to the site with truck or ship to the offshore drilling rigs. The solid particle phase of the OBM emulsion often settles during transportation and the emulsion therefore needs reconditioning on site. However, preparing on the order of 100 m3 of stable emulsion requires both high shear and high elongation as well as time and space due to the large volumes of fluid involved. Current shear guns used offshore are not efficient enough and do not provide sufficient emulsification to generate a stable fluid. Therefore, a common practice is also to use the bit nozzles as emulsification device when adding fresh drilling fluid to the circulating fluid. This must be done at a slow rate to ensure the stability of the fluid and is therefore a time-consuming process. A compact solution for efficient on-site recondition emulsification of the drilling fluid would therefore reduce time and costs of drilling operations.

On-site pump pressure capacity may be limited, and on-site energy use should ideally be kept as low as possible. With these restrictions in mind, it is desirable to be able to provide a stable emulsion with as little pressure drop as possible, while high pump rate is also preferable in order to minimize mixing time. Both criteria favour larger nozzle sizes.

We here present results from full-scale laboratory tests with a dual shear gun unit, investigating the effect of different design parameters on the oil-water mixing process and on the stability of the resulting dispersion. Surfactants (emulsifiers) have not been added, to allow fluids to separate and to be re-used after each test, and separation time is used as an indicator of droplet size and thus of the expected fluid stability in a system with emulsifiers.

In this paper we present and discuss experimental results of effects of nozzle sizes, nozzle-nozzle distance, pressure drop over nozzles, flow rates (which depend on pressures and nozzle sizes), as well as fluid aging.
Analysis of the Dynamic Response of ROV System Experiencing Vessel Motion During Deployment and Recovery Processes
Authors: Yu Xiaoqi , Guo Yucheng , Guo Shuangxi , Liu Xiangxu , Kong Yue , Chen Weimin
Published: August 2024

Remotely operated vehicle (ROV) system is significantly affected by the excitations coming from the top-end vessel motion and the hydrodynamic disturbances. Especially, during initial deployment and final recovery stages, the cable length might be so short that the relative motion between the ROV and the vessel may cause a severe collision. At the same time, the cable tension can also be changed by the ROV motion, and consequently cable slack may occur, which seriously affects structural safety. This study focuses on the dynamic responses of ROV system induced by the vessel heave during initial deployment and final recovery processes. Through numerical simulation, the ROV response and cable tension time histories of the ROV system with moving boundary, also considering hydrodynamic force on ROV, are presented. It is found that the vessel heave induces the parametric excitation response to the ROV system. The influences of vessel motion amplitude, vessel motion frequency, and initial angular displacement of ROV on the responses of ROV system are discussed. Meanwhile, the governing equation of ROV motion with a vertical moving boundary is established, and a dimensionless control parameter called amplitude-frequency factor which characterizes the strength of vessel heave is proposed. Under the nonlinear damping generated by hydrodynamic force, the parametric resonance can be excited when the amplitude-frequency factor reaches the threshold. The hydrodynamic damping ratio is fitted based on the numerical simulation results. Finally, under consideration of the nonlinear damping effect, the unstable regions of vessel motion amplitude and frequency at different displacement amplitudes are obtained.
Soil Deformation and Erosion Near Mooring Chains in Clay Based on Cyclic T-Bar Tests
Authors: Rui Shengjie , Zhou Zefeng , Jostad Hans Petter , Yang Hongkuan , Dou Yuzhe , Wang Baoxuan
Published: August 2024

Soil deformation and erosion induced by anchor chain motion has a significant influence on the formation of trenches into the seabed near the touchdown area. However, the soil deformation and erosion are not well understood in the present trench formation, which limits the wide application in the prediction method. This paper presents a series of monotonic and cycle T-bar penetration tests to investigate the soil deformation and erosion phenomena at the seabed. Different soil undrained shear strengths were adopted, and a camera was used to record the soil deformation in real time. During the monotonic and the first penetration in the cyclic tests, the soil was displaced by the T-bar. In the cyclic tests, the degradation of soil resistance mainly appears in the first 20 cycles, and the final resistance is originated from the water replacement in the trench. The soil erosion near the T-bar mainly appears in the cracks formed during the initial penetration. When the water in the trench is replaced by the T-bar, water flows and erodes fine particles through the cracks. The trenches are initially caused by the T-bar penetration, and then the soil along the trench wall and bottom are eroded away during cyclic loading to form stable trench profiles.
The Optimization of Nozzle-Diffuser Duct for an Innovative Wave Energy Conversion System
Authors: Wu Shing-nan , Yeh Po-hung , Chen Bang-fuh
Published: August 2024

An innovative wave energy converter is proposed. In present study, a nozzle-diffuser duct (NDD) is used to transfer wave energy into current energy. If the energy is to be transferred more efficiently, the NDD needs to be optimally designed. First of all, the model in present paper is introduced. Then, the research methods, including the numerical method as well as the optimization algorithm, are explained. Before further investigation, validation needs to be carried out. After the simulation result is validated by comparison with previous studies, the overall discrepency is less than 4 %. Therefore, more advanced analysis is then performed. The NDD geometry is optimized by the Taguchi method, initiated by a Japanese scholar and then widely adopted and recognized worldwide due to the method’s reliability. The result shows that when NDD geometry is optimally designed, the energy flux generated by NDD reaches the maximal value, and so does the velocity inside NDD. The best design outperforms the best case in the nine selected cases by 27%. This also implies that when the wave condition of Hualien Harbor in the east coast of Taiwan is applied, the feasibility of the NDD installation to garner energy from the wave is possible.
Efficiency and Innovation in Offshore Renewable Energy: A Surrogate Modeling Approach to Mooring System Optimization
Authors: Moradinia Zohreh , Vandierendonck Hans , Murphy Adrian
Published: August 2024

This paper introduces an advanced framework for the multi-objective optimization of mooring systems in offshore renewable energy applications. Employing a machine learning-based surrogate model integrated with the Non-dominated Sorting Genetic Algorithm II (NSGA-II), the approach efficiently navigates the complex design space. The framework, demonstrated through the optimization of a mooring system for a wave energy converter, emphasizes minimizing manufacturing costs and maximizing x-direction offset motion while adhering to specified constraints. Utilizing validated numerical models, the surrogate model is trained on a comprehensive dataset, enabling accurate predictions of tension and platform motion. The integration of a genetic algorithm systematically explores design possibilities, with the surrogate model validating each generation, eliminating the need for time-intensive simulations. The study produces a spectrum of optimal solutions, offering insights into the intricate interplay between design modifications, cost considerations, and platform motion. This nuanced understanding facilitates informed decision-making in the realm of offshore renewable energy projects, providing a valuable contribution to mooring system design optimization.
Customizable beam splitting in planar adiabatic acoustic couplers composed of cylindrical scatterers
Authors: Lü Cheng , Tang Shuai , Yao Jiabao , Song Jie , Jiang Yongyuan
Published: August 2024

In this work, five-waveguide (five-WG) acoustic couplers with planar configurations are designed based on quantumlike adiabatic transfer, through which the incident waves can efficiently transfer from the middle WG to the other two WGs with a customized intensity ratio. The five WGs are connected by space-varying cylindrical scatterers, and the coupling between two adjacent WGs is determined by two Gaussian pulses with a certain delay. Since the evolution process of acoustic waves can adiabatically follow the dark state, the coupler could have a broadband and stable performance. Moreover, it is easy to change the ratio of the beam splitting by utilizing different peak values of the coupling between the middle three WGs. The agreements between analytical, numerical, and experimental results confirm the feasibility of the design, providing an effective solution for high-performance acoustic beam splitters with customizable output intensities.
Stress Drives Soccer Athletes’ Wellness and Movement: Using Convergent Cross-Mapping to Identify Causal Relationships in a Dynamic Environment
Authors: Stern Benjamin D. , Deyle Ethan R. , Hegedus Eric J. , Munch Stephan B. , Saberski Erik
Published: August 2024

Purpose: Prediction of athlete wellness is difficult—or, many sports-medicine practitioners and scientists would argue, impossible. Instead, one settles for correlational relationships of variables gathered at fixed moments in time. The issue may be an inherent mismatch between usual methods of data collection and analysis and the complex nature of the variables governing athlete wellness. Variables such as external load, stress, muscle soreness, and sleep quality may affect each other and wellness in a dynamic, nonlinear, way over time. In such an environment, traditional data-collection methods and statistics will fail to capture causal effects. If we are to move this area of sport science forward, a different approach is required. Methods: We analyzed data from 2 different soccer teams that showed no significance between player load and wellness or among individual measures of wellness. Our analysis used methods of attractor reconstruction to examine possible causal relationships between GPS/accelerometer-measured external training load and wellness variables. Results: Our analysis showed that player self-rated stress, a component of wellness, seems a fundamental driving variable. The influence of stress is so great that stress can predict other components of athlete wellness, and, in turn, self-rated stress can be predicted by observing a player’s load data. Conclusion: We demonstrate the ability of nonlinear methods to identify interactions between and among variables to predict future athlete stress. These relationships are indicative of the causal relationships playing out in athlete wellness over the course of a soccer season.
Inequality in Physical Activity in Organized Group Settings for Children: A Cross-Sectional Study
Authors: Rogers Ann E. , Wichman Christopher S. , Schenkelberg Michaela A. , Dzewaltowski David A.
Published: August 2024

Background: Adult-led organized settings for children (eg, classrooms) provide opportunities for physical activity (PA). The structure of setting time may influence inequalities (ie, unequalness) in the distribution of PA. This study examined differences in PA inequality by setting and time-segment purpose in time-segmented organized group settings for children. Methods: PA and setting meetings were assessed using accelerometer and video observation data from school, before-/after-school, and youth club groups (n = 30) for third- through sixth-grade children (n = 699) in 2 rural US communities. Meetings (n = 130) were time-segmented into smaller units (sessions; n = 835). Each session was assigned a purpose code (eg, PA). Accelerometer data were paired with the meetings and sessions, and the Gini coefficient quantified inequality in activity counts and moderate to vigorous PA minutes for each segment. Beta generalized estimating equations examined differences in PA inequality by setting and session purpose. Results: Activity count inequality was lowest (P < .05) during youth club meetings (Gini = 0.17, 95% CI, 0.14–0.20), and inequality in moderate to vigorous PA minutes was greatest (P < .01) during school (Gini = 0.34, 95% CI, 0.30–0.38). Organized PA sessions (Gini = 0.20, 95% CI, 0.17–0.23) had lower activity count inequality (P < .0001) than academic (Gini = 0.30, 95% CI, 0.27–0.34), enrichment (Gini = 0.31, 95% CI, 0.27–0.36), and nonactive recreation (Gini = 0.30, 95% CI, 0.25–0.34) sessions. Inequality in moderate to vigorous PA minutes was lower (P < .05) in organized PA (Gini = 0.26, 95% CI, 0.20–0.32) and free play (Gini = 0.28, 95% CI, 0.19–0.39) than other sessions. Conclusions: PA inequality differed by setting time structure, with lower inequality during organized PA sessions. The Gini coefficient can illuminate PA inequalities in organized settings and may inform population PA improvement efforts in rural communities.
The Politics of Taking a Knee: Journalist Demographics and Media Analysis of the Colin Kaepernick Protest
Authors: Deeb Alexander , Love Adam , Crowe Patrick
Published: August 2024

During the 2016 National Football League season, Colin Kaepernick was the subject of intense media scrutiny as he protested racial injustice by taking a knee during the national anthem. Given the fact that the sports media is disproportionately dominated by White men, this study analyzed media framing of Kaepernick with particular consideration to the racial demographics of journalists producing media coverage. Our analysis indicates that positive articles (i.e., articles that praised Kaepernick) generally outnumbered negative articles (i.e., articles that criticized Kaepernick), but articles written by White men were significantly more likely to use negative frames, whereas authors of color more frequently framed Kaepernick in a positive way. Ultimately, we conceptualize media coverage of Kaepernick’s protest as a racial project that seeks to either reproduce or subvert meanings associated with race and racism.
Disruption to
de novo
uridine biosynthesis alters β-1,3-glucan masking in
Candida albicans
Authors: Mangrum Mikayla M. , Vogel Amanda K. , Wagner Andrew S. , King Ainsley E. , Miao Jian , Zhou Yue , Phillips Elise K. , Peters Brian M. , Reynolds Todd B.
Published: August 2024

The uridine derivatives UDP-glucose and UDP-
N
-acetylglucosamine are important for cell wall construction as they are the precursors for the synthesis of β-1,3-glucan and chitin, respectively. Previous studies have demonstrated attenuated virulence of uridine auxotrophs in mice, which has been attributed to insufficient uridine levels for growth in the host. We have discovered that uridine deprivation in the uridine auxotroph
ura3
ΔΔ disrupts cell wall architecture by increasing surface mannans, exposing β-1,3-glucan and chitin, and decreasing UDP-sugar levels. Cell wall architecture and UDP-sugars can be rescued with uridine supplementation. The cell wall architectural disruptions in the
ura3
ΔΔ mutant also impact immune activation since the mutant elicited greater TNFα secretion from RAW264.7 macrophages than wild type. To determine if cell wall defects contributed to decreased virulence in the
ura3
ΔΔ mutant, we used a murine model of systemic infection. Mice infected with the
ura3
ΔΔ mutant exhibited increased survival and reduced kidney fungal burden compared with mice infected with wild type. However, suppression of the immune response with cyclophosphamide did not rescue virulence in mice infected with the
ura3
ΔΔ mutant, indicating the attenuation in virulence of uridine auxotrophs can be attributed to decreased growth in the host but not increased exposure of β-1,3-glucan. Moreover, the
ura3
ΔΔ mutant is unable to grow on
ex vivo
kidney agar, which demonstrates its inability to colonize the kidneys due to poor growth. Thus, although uridine auxotrophy elicits changes to cell wall architecture that increase the exposure of immunogenic polymers, metabolic fitness costs more strongly drive the observed virulence attenuation.

IMPORTANCE

Candida albicans
is a common cause of bloodstream infections (candidemia). Treatment of these bloodstream infections is made difficult because of increasing antifungal resistance and drug toxicity. Thus, new tactics are needed for antifungal drug development, with immunotherapy being of particular interest. The cell wall of
C. albicans
is composed of highly immunogenic polymers, particularly β-1,3-glucan. However, β-1,3-glucan is naturally masked by an outer layer of mannoproteins, which hampers the detection of the fungus by the host immune system. Alteration in cell wall components has been shown to increase β-1,3-glucan exposure; however, it is unknown how the inability to synthesize precursors to cell wall components affects unmasking. Here, we demonstrate how cell wall architecture is altered in response to a deficit in precursors for cell wall synthesis and how uridine is a crucial component of these precursors.
Multiplexed real-time PCR for the detection and differentiation of
Klebsiella pneumoniae
O-antigen serotypes
Authors: Slater Damien , Hutt Vater Kian , Sridhar Sushmita , Hwang Wontae , Bielawski Derek , Turbett Sarah E. , LaRocque Regina C. , Harris Jason B.
Published: August 2024

Klebsiella pneumoniae
has emerged as a global health threat due to its role in the spread of antimicrobial resistance and because it is a frequent cause of hospital-acquired infections and neonatal sepsis. Capsular and lipopolysaccharide (LPS) O-antigen polysaccharide surface antigens are major immunogens that are useful for strain classification and are candidates for vaccine development. We have developed real-time PCR reagents for molecular serotyping, subtyping, and quantitation of the most prevalent LPS O-antigen types (i.e., O1, O2, O3, and O5) of
Klebsiella pneumoniae
. We describe two applications for this O-typing assay: for screening culture isolates and for direct typing of
Klebsiella pneumoniae
present in stool samples. We find 100% concordance between the results of the O-typing assay and whole-genome sequencing of 81 culture isolates, and >90% agreement in O-typing performed directly on specimens of human stool, with disagreement arising primarily from a lack of sensitivity of the culture-based comparator method. Additionally, we find evidence for mixed O-type populations at varying levels of abundance in direct tests of stool from a hospitalized patient population. Taken together, these results demonstrate that this novel O-typing assay can be a useful tool for
K. pneumoniae
epidemiologic and vaccine studies.

IMPORTANCE

Klebsiella pneumoniae
is an important opportunistic pathogen. The gastrointestinal (GI) tract is the primary reservoir of
K. pneumoniae
in humans, and GI carriage is believed to be a prerequisite for invasive infection. Knowledge about the dynamics and duration of GI carriage has been hampered by the lack of tools suitable for detection and strain discrimination. Real-time PCR is particularly suited to the higher-throughput workflows used in population-based studies, which are needed to improve our understanding of carriage dynamics and the factors influencing
K. pneumoniae
colonization.
Late Eocene sodic calc-alkaline lamprophyre in Gangdese batholith, southern Tibet: Implications for mantle metasomatism by carbonatitic melt
Authors: Li Guangxu , Zeng Lingsen , Gao Li-E , Yan Lilong , Zhao Linghao , Tian Yihong
Published: August 2024

Similar to oceanic lithosphere, the progressive and continuous subduction of continental lithosphere could lead to early dehydration and subsequent melting of the subducting slab. Melting subducted carbonate materials could release carbonatitic melts and trigger melting of the overlying lithospheric mantle and the formation of different types of alkaline and calc-alkaline rocks. In this paper, we present a study on a suite of mafic dikes of sodic calc-alkaline lamprophyre (CAL) composition in the eastern Gangdese batholith, southern Tibet. These dikes, emplaced ca. 36.9 ± 0.3 Ma, are characterized by (1) high CaO and Na2O but low K2O content and hence exceptionally high Na2O/K2O ratios (>2.3 up to 68.1); (2) negative anomalies of Nb-Ta-Zr-Hf-Ti, and (3) strong enrichment in light rare earth elements and large ion lithophile elements. Significantly low Rb/Sr (<0.06) and Dy/Yb (<2.5), coupled with high Ba/Rb (>31 up to 1447), suggest their derivation by low-degree partial melting of amphibole-bearing peridotite within the garnet-facies lherzolite field. Compared to those in depleted mantle, they are also characterized by high initial 87Sr/86Sr (0.7074–0.7078), 207Pb/204Pb(t) (15.74–15.75), and 208Pb/204Pb(t) (39.39–39.41), but relatively low εNd(t) values (−1.8 to +2.4) and 206Pb/204Pb(t) (18.81–18.82) and zircon εHf(t) values (+2.7 to +7.3). In terms of Sr-Nd isotope systematics, they are more enriched than those in Mesozoic–Cenozoic magmatic rocks, but more depleted than younger (after 30 Ma) potassic–ultrapotassic rocks within the Gangdese batholith, which requires a different mantle source. These lamprophyres contain abundant carbonate minerals with a linear correlation between CaO and CO2, which suggests primary carbonate phases and a mantle source region rich in carbonate materials. We propose that sodic CAL was generated by the partial melting of an enriched lithospheric mantle metasomatized by carbonatitic melts derived from the subducted Indian continental crust. The emplacement of lamprophyres is associated with E-W extension induced by local post-collisional delamination of thickened lower continental crust (~75 km) after the collision between India and Asia.
Cognitive behavioural therapy for insomnia (CBT-I) in schizophrenia and schizoaffective disorder: protocol for a randomised controlled trial
Authors: Tanskanen Tuula Elina , Wegelius Asko , Härkönen Tiina , Gummerus Eero-Matti , Stenberg Jan-Henry , Selinheimo Sanna Ilona Karoliina , Alakuijala Anniina , Tenhunen Mirja , Paajanen Teemu , Järnefelt Heli , Kajaste Soili , Blom Kerstin , Kieseppä Tuula , Tuisku Katinka , Paunio Tiina
Published: August 2024

Introduction

Insomnia is a common symptom among patients with schizophrenia and schizoaffective disorder, negatively impacting symptom severity, functioning and well-being; however, it is rarely the direct focus of treatment. The main recommended treatment for insomnia is cognitive behavioural therapy (CBT-I). There is some evidence that CBT-I can also be used to treat insomnia in patients with schizophrenia, but only a few randomised controlled trials (RCTs) have been published. The aim of this ongoing RCT is to determine whether we can alleviate symptoms of insomnia and improve the quality of life in patients with schizophrenia and schizoaffective disorder through CBT-I delivered via the internet or in a group mode.

Methods and analyses

The aim of this study is to recruit 84–120 outpatients from the Psychosis Clinics of Helsinki University Hospital and the City of Helsinki Health Services. The main inclusion criteria are a diagnosis of schizophrenia or schizoaffective disorder and self-reported sleep problems. The study will be performed on a cyclic basis, with a target of 12–24 patients per cycle. Participants are randomly assigned into three groups: (1) a group receiving only treatment as usual (TAU), (2) internet-based individual therapy for insomnia (iCBT-I)+TAU or (3) group therapy for insomnia (GCBT-I) conducted via a virtual platform+TAU. The primary outcome measures are quantitative changes in the Insomnia Severity Index score and/or changes in health-related quality of life using the 15D quality of life measure. Secondary outcomes include self-reported variables for sleep, health, stress and the severity of psychotic and depressive symptoms; objective outcomes include actigraphy and bed sensor data to evaluate circadian rhythms and motor activity. Outcome measures are assessed at baseline and after the treatment period at weeks 12, 24 and 36.

Ethics and dissemination

The Coordinating Ethics Committee of the Hospital District of Helsinki and Uusimaa, Finland, approved the study protocol. The results will be published in peer-reviewed journals.

Trial registration number

NCT04144231.
Development, implementation and usefulness of an intervention to support psychological resilience during the COVID-19 pandemic: a study from a Swedish hospital based on interviews, documents and a survey
Authors: Taxén Mariel , Tolf Sara , Appelbom Sophia , Sjöström-Bujacz Aleksandra , Baresso Ninveh , Herber Karin , Johansson Annika , Keita My , Ramstedt Lotta , Bringby Anna Wik , Stenfors Terese , Mazzocato Pamela
Published: August 2024

Objectives

A range of interventions to support psychological resilience among healthcare workers were provided in hospitals during the COVID-19 pandemic. Most research has focused on the content and experience of these interventions, but less is known about their implementation. The aim of this study was to increase understanding of the development, implementation and perceived usefulness of an intervention to support psychological resilience among healthcare workers at a Swedish hospital during the pandemic.

Design

This study employs interviews and documents to explore the development and implementation of support activities and a survey to assess the usefulness of the activities (on a scale from 1 to 5). Qualitative content analysis was used to analyse the interview data and documents. Descriptive statistics were used to analyse the survey data.

Settings

A tertiary hospital in the outskirts of Region Stockholm.

Participants

Eight individual interviews were conducted with actors involved in developing the intervention. 286 healthcare workers answered the survey.

Results

Support activities were developed and implemented by an internal multidisciplinary group who continuously identified and adapted activities to the needs of staff. The strategy of involving existing resources to jointly develop and continuously adapt staff support activities was beneficial for the implementation and longevity of the intervention. Scheduling difficulties were one of the challenges. The mean ratings of the activities ranged from 2.27 for one-on-one counselling to 3.25 for physical activity. Licensed practical nurses generally valued the activities higher than other professional groups.

Conclusions

The provision of activities to support psychological resilience in a crisis is facilitated by the ability of an organisation to use current resources in the face of a crisis, which is a sign of organisational resilience. Leaders who act quickly and create the conditions to test and learn under uncertainty can contribute to developing effective responses to a crisis.
Effects of ultrasound-guided thoracolumbar interfascial plane block combined with general anaesthesia versus general anaesthesia alone on emergence agitation in children with cerebral palsy undergoing selective posterior rhizotomy: protocol for a randomised controlled clinical trial
Authors: Li Xueyang , Huang Xiao , Xu Kai , Zan Jingwei , Liu Guokai , Sun Yuan , Ren Huilong
Published: August 2024

Introduction

Selective posterior rhizotomy (SPR) is a preferred procedure for relieving spastic children with cerebral palsy, but it is associated with severe pain and significant emergence agitation (EA). The thoracolumbar interfascial plane (TLIP) block provides an effective blockade to the dorsal branch of the spinal nerve. We hypothesise that the TLIP block may be an effective tool to alleviate EA and postoperative pain scores in children with cerebral palsy undergoing SPR.

Methods and analysis

This study is a single-centre, randomised, parallel-controlled trial being conducted in Beijing, China. A total of 50 paediatric patients with cerebral palsy scheduled for SPR are randomised in a 1:1 ratio to receive bilateral TLIP block with 0.2% ropivacaine 0.5 mL/kg or control. Patients in the TLIP group receive general anaesthesia combined with TLIP block, while patients in the control group receive only general anaesthesia, without a TLIP block. The primary outcome is the Paediatric Anaesthesia Emergence Delirium Score. The secondary outcomes are the incidence of EA, the Wong-Baker Faces Pain-rating Scale, the perioperative haemodynamics, the intraoperative remifentanil and propofol dosage, the extubation time and recovery time, and adverse reactions.

Ethics and dissemination

This study was approved by the Ethics Committee of Dongzhimen Hospital, Beijing University of Chinese Medicine on 21 September 2023 (2023DZMEC-379–02). Written informed consent is obtained from the legal guardian of each patient. The results of this study will be published in peer-reviewed international journals.

Trial registration number

ChiCTR2300076397
Efficacy and safety of dynamic arterial elastance for weaning vasopressor support in septic shock patients: a randomised controlled trial protocol
Authors: Alvarado Sánchez Jorge Iván , Montañez-Nariño Andrea Valentina , Cárdenas-Bolivar Yenny Rocio , Stozitzky-Ríos Maria Valentina , Mora-Salamanca Andrés Felipe
Published: August 2024

Introduction

The dynamic arterial elastance (EaDyn), calculated as pulse pressure variation divided by stroke volume variation, has been studied as a predictor of vasopressor weaning. However, its potential as a haemodynamic tool for tapering off vasopressors in patients with sepsis remains unexplored. Therefore, our study aimed to assess whether using EaDyn for weaning vasopressor support could reduce the duration of vasopressor support in patients with sepsis.

Methods and analysis

This pragmatic single-centre controlled clinical trial will take place at Fundación Santa Fe de Bogotá, Colombia. Adult patients diagnosed with septic shock according to the sepsis-3 criteria and a Sequential Organ Failure Assessment score ≥4 will be included. A total of 114 patients (57 per group) will undergo conventional critical care monitoring, and the weaning of vasopressor support will be initiated based on the EaDyn or mean arterial pressure (MAP), depending on the assigned group. EaDyn will be estimated based on the measurements obtained from a PiCCO device connected to a PulsioFlex Monitoring Platform (PULSION Medical Systems SE, Feldkirchen, Germany). Our primary outcome is the difference in vasopressor support duration between the EaDyn and MAP groups.

Participants and statisticians performing the statistical analysis will be blinded to the group allocation. Dependent and independent variables will be analysed through univariate and multivariate statistical tests. Since we will perform three repeated measurements for analysis, we will implement a Bonferroni post hoc correction. Additionally, Cox regression and Kaplan-Meier analyses will be conducted to address objectives related to time.

Ethics and dissemination

This study was approved by the Ethics Committee at Fundación Santa Fe de Bogotá (CCEI-16026-2024). Written informed consent will be obtained from all participants. The results will be disseminated through publication in peer-reviewed journals and presentations at national and international events.

Trial registration number

NCT06118775.
What do patients with heart failure disclose about medication adherence at home to their hospital and primary care doctors? Exploratory interaction-based observational cohort study
Authors: Frigaard Christine , Menichetti Julia , Schirmer Henrik , Bjørnstad Herman , Breines Simonsen Tone , Wisløff Torbjørn , Gulbrandsen Pål , Gerwing Jennifer
Published: August 2024

Objectives

The main objective of this study was twofold: to investigate what kind of information patients with heart failure (HF) tell their doctors about their medication adherence at home, and how often such information is provided in consultations where medication reconciliation is recommended. To meet these objectives, we developed an analysis to recognise, define, and count (1) patient utterances including medication adherence disclosures in clinical interactions (MADICI), (2) MADICI including red-flags for non-adherence, and (3) MADICI initiated by patients without prompts from their doctor.

Design

Exploratory interaction-based observational cohort study. Inductive microanalysis of authentic patient–doctor consultations, audio-recorded at three time-points for each patient: (1) first ward visit in hospital, (2) discharge visit from hospital, and (3) follow-up visit with general practitioner (GP).

Setting

Norway (2022–2023).

Participants

25 patients with HF (+65 years) and their attending doctors (23 hospital doctors, 25 GPs).

Results

We recognised MADICI by two criteria: (1) they are about medication prescribed for use at home, AND (2) they involve patients’ action, experience, or stance regarding medications. Using these criteria, we identified 427 MADICIs in 25 patient trajectories: 143 (34%) at first ward visit (min–max=0–35, median=3), 57 (13%) at discharge visit (min–max=0–8, median=2), 227 (53%) at GP-visit (min–max=2–24, median=7). Of 427 MADICIs, 235 (55%) included red-flags for non-adherence. Bumetanide and atorvastatin were most frequently mentioned as problematic. Patients initiated 146 (34%) of 427 MADICIs. Of 235 ‘red-flag MADICIs’, 101 (43%) were initiated by patients.

Conclusions

Self-managing older patients with HF disclosed information about their use of medications at home, often including red-flags for non-adherence. Patients who disclosed information that signals adherence problems tended to do so unprompted. Such disclosures generate opportunities for doctors to assess and support patients’ medication adherence at home.