bluuebunny/crossref_metadata_2025 huggingface dataset:
Vision Guided Dynamic Synchronous Path Tracking Control of Dual Manipulator Cooperative System
Authors: Bai Quan , Li Pengcheng , Tian Wei , Shen Jianxin , Li Bo , Hu Junshan
Published: May 2023

Compared with a single manipulator manufacturing cell, a dual manipulator cooperative system has more advantages in reconfigurability and flexibility. However, there are calibration errors and multi-source disturbances in the collaborative process, which lead to the processing trajectory accuracy defects of large-scale associated machining features. To solve the above problems, a practical path tracking synchronous control algorithm based on position-based visual servoing (PBVS) is proposed in this paper for the dual manipulator cooperative system, the proposed dynamic path tracking cross-coupled sliding mode controller (PTCSMC) scheme can realize dynamic paths correction while executing the pre-planned paths. In addition, for the cross-coupled technology to be applied into the proposed control algorithm for dynamic path tracking based on the real-time feedback of the highly repeatable 3D visual measurement instrument (VMI), the tracking and synchronous errors of the dual manipulators converge synchronously to zero. Finally, the stability of proposed control algorithm is proven by the Lyapunov method. In the end, the real-time line and circle path tracking experimental results using two industrial manipulators demonstrate the effectiveness of the proposed algorithm.
A Dimension Selection-Based Constrained Multi-Objective Optimization Algorithm Using a Combination of Artificial Intelligence Methods
Authors: Wu Di , Sotnikov Dmitry , Gary Wang G. , Coatanea Eric , Lyly Mika , Salmi Tiina
Published: May 2023

The computational cost of modern simulation-based optimization tends to be prohibitive in practice. Complex design problems often involve expensive constraints evaluated through finite element analysis or other computationally intensive procedures. To speed up the optimization process and deal with expensive constraints, a new dimension selection-based constrained multi-objective optimization (MOO) algorithm is developed combining least absolute shrinkage and selection operator (LASSO) regression, artificial neural networks, and grey wolf optimizer, named L-ANN-GWO. Instead of considering all variables at each iteration during the optimization, the proposed algorithm only adaptively retains the variables that are highly influential on the objectives. The unselected variables are adjusted to satisfy the constraints through a local search. With numerical benchmark problems and a simulation-based engineering design problem, L-ANN-GWO outperforms state-of-the-art constrained MOO algorithms. The method is then applied to solve a highly complex optimization problem, the design of a high-temperature superconducting magnet. The optimal solution shows significant improvement as compared to the baseline design.
Development of a Novel Ground Test Facility for Aircraft Environmental Control System
Authors: Chowdhury Shafayat Hasan , Ali Fakhre , Jennions Ian K.
Published: May 2023

In this article, the development and experimental investigation of a Boeing 737 aircraft environmental control system (ECS) passenger air conditioner (PACK) has been reported. The PACK is the heart of the ECS that conditions bleed air prior to supplying it to the cabin and avionics bay. Its capability to mask fault occurrences has resulted in increased unscheduled maintenance of the system. As such it has been a key research topic to understand PACK performance characteristics in order to support an accurate diagnostic solution. This article is a continuation of the authors’ work on the development of a systematically derived PACK simulation model and reports the overall development and qualification of a novel in situ ground test facility (GTF) for the experimental investigation of a B737-400 aircraft PACK under various operating modes, including the effect of trim air system. The developed GTF enables the acquisition of the temperature, pressure, and mass flow data throughout the PACK. The overall process of instrumentation selection, installation, sensor uncertainty, and testing in terms of data repeatability and consistency has been reported. The acquired data are then employed to conduct verification and validation of the SESAC (simscape ECS simulation under all conditions) simulation framework. The reported research work therefore enables the advancement in the level of scientific understanding corresponding to the ECS PACK operation under real operating conditions, and therefore supports the development of a robust simulation framework for ECS fault diagnostics at the system level.
Thermal Management System of Vapor Compression for Downhole Instrument
Authors: Tao Qiuyang , Wei Minghui , Chen Hongjun , Deng Aihua , He Yilin
Published: May 2023

As the depth of oil and gas exploration increases, downhole electronics face the threat of high-temperature failure. At present, passive cooling technology has the problem of short working time, while active cooling technology has low energy utilization. This paper presents a thermal management system of vapor compression with a combination of active and passive cooling. The system uses insulation materials to isolate the high-temperature environment, thermally conductive silicone grease to strengthen the heat exchange in the evaporator, and vapor compression refrigeration cycles to absorb internal heat. The coefficient of performance (COP), exergy destruction and exergy efficiency of octane, nonane, and cyclohexane as refrigerants were examined, and the effects of different insulation materials on refrigeration performance were studied from both theoretical and numerical perspectives. The results showed that cyclohexane exhibited the best cooling capacity with a COP of 1.296 and a exergy efficiency of 49.21%. The thermal management system cooling performance is optimal when the insulation material is a vacuum flask, with an effective cooling capacity of 121.7 W.
Energy and Exergy Analysis of an Automobile Hybrid Ejector Refrigeration System Utilizing Its Exhaust Waste Heat
Authors: Abbady Karim , Al-Mutawa Nawaf , Almutairi Abdulrahman
Published: May 2023

A major current focus of refrigeration and air-conditioning research is energy usage and environmental impact (e.g., the influence of refrigerants and air-conditioning systems on ozone layer depletion and global warming). The ejector-based refrigeration system is a technology that, it is hoped, can save power while using environment-friendly refrigerants to reduce any adverse effects on nature. The reduction of compressor dependency is the first and essential aim of this study; the second is to demonstrate the replacement of R134a with the new refrigerant R1234yf in motor vehicle air-conditioning systems, establishing the benefits of employing R1234yf in conjunction with a hybrid air-conditioning system. In such a system, the engine's exhaust gases are used to operate the ejector. A numerical model has been developed which estimates the ejector entrainment ratio at a specified spindle and primary nozzle exit position. A theoretical model using energy and exergy analysis illustrates the impact of hybrid systems on performance under different operating conditions (i.e., engine exhaust, ambient air, and evaporator temperatures). At a specified exhaust temperature, a detailed comparison has been conducted between a current air-conditioning system with R134a and the hybrid system with R1234yf. It was found that the R1234yf hybrid system reduced compressor energy consumption by 44.43% and operating exhaust heat levels by 12.79%. The coefficient of performance increased by 41.42%, while the exergetic efficiency reduced from 37.14% to 13.85%. Cooling capacity dropped by 12.73%. The hybrid air-conditioning system based on R1234yf demonstrated tremendous potential for improving vehicle air-conditioning system efficiency.
BANCOS DE SILICON VALLEY, HOLOGRAFÍA Y ANTROPOLOGÍA CUÁNTICA
Authors: López Martínez Sergio Daniel
Published: May 2023

Roy Wagner era un antropólogo encantador. Cuando uno de sus asistentes descubría que un estudiante había copiado y pegado de Internet el texto de un trabajo, acudía a él para hacer una prudente consulta antes de ponerle un suspenso. Entonces Wagner se enfadaba, fruncía el ceño y le decía indignado al asistente: “¡Qué vergüenza! ¡ponle un Notable Bajo!”. El estudiante, que apenas tendría poco más de una nota media de aprobado, acababa convirtiendo uno de sus habituales desastres en una gran celebración. Y el asistente, claro, quedaba aún más indignado. (...)
Under-Appreciated Phylogroup Diversity of
Escherichia coli
within and between Animals at the Urban-Wildland Interface
Authors: Lagerstrom Katherine M. , Hadly Elizabeth A.
Published: May 2023

To our knowledge, neither the phylogroup diversity of
E. coli
within individual wild animals nor that within an interacting multispecies community have previously been assessed. In doing so, we uncovered the globally known phylogroup diversity from an animal community on a preserve imbedded in a human-dominated landscape.
Coral Disease and Ingestion: Investigating the Role of Heterotrophy in the Transmission of Pathogenic
Vibrio
spp. using a Sea Anemone (
Exaiptasia pallida
) Model System
Authors: Norfolk William A. , Melendez-Declet Carolina , Lipp Erin K.
Published: May 2023

The front line of pathogen defense in corals is the mucus membrane. This membrane coats the surface body wall creating a semi-impermeable layer that inhibits pathogen entry from the ambient water both physically and biologically through mutualistic antagonism from resident mucus microbes.
Geometric Remodeling of Nitrilase Active Pocket Based on ALF-Scanning Strategy To Enhance Aromatic Nitrile Substrate Preference and Catalytic Efficiency
Authors: Wang Zi-Kai , Gong Jin-Song , Feng Dan-Ting , Su Chang , Li Hui , Rao Zhi-Ming , Lu Zhen-Ming , Shi Jin-Song , Xu Zheng-Hong
Published: May 2023

In this study, the active pocket was largely remodeled based on the ALF-scanning strategy we developed. It is believed that ALF-scanning not only could be employed for substrate preference modification but might also play a role in protein engineering of other enzymatic properties, such as substrate region selectivity and substrate spectrum.
Full Copper Resistance in Cupriavidus metallidurans Requires the Interplay of Many Resistance Systems
Authors: Hirth Niklas , Gerlach Michelle-Sophie , Wiesemann Nicole , Herzberg Martin , Große Cornelia , Nies Dietrich H.
Published: May 2023

The ability of bacteria to maintain homeostasis of the essential-but-toxic “Janus”-faced element copper is important for their survival in many natural environments but also in case of pathogenic bacteria in their respective host. The most important contributors to copper homeostasis have been identified in the last decades and comprise PIB1-type ATPases, periplasmic copper- and oxygen-dependent copper oxidases, transenvelope efflux systems, and glutathione; however, it is not known how all these players interact.
Synthesizing Research Narratives to Reveal the Big Picture: a CREATE(S) Intervention Modified for Journal Club Improves Undergraduate Science Literacy
Authors: Goodwin Emma C. , Shapiro Casey , Freise Amanda C. , Toven-Lindsey Brit , Moberg Parker Jordan
Published: May 2023

Communicating science effectively is an essential part of the development of science literacy. Research has shown that introducing primary scientific literature through journal clubs can improve student learning outcomes, including increased scientific knowledge.
Immunization with Recombinant Accessory Protein-Deficient SARS-CoV-2 Protects against Lethal Challenge and Viral Transmission
Authors: Ye Chengjin , Park Jun-Gyu , Chiem Kevin , Dravid Piyush , Allué-Guardia Anna , Garcia-Vilanova Andreu , Pino Tamayo Paula , Shivanna Vinay , Kapoor Amit , Walter Mark R. , Kobie James J. , Plemper Richard K. , Torrelles Jordi B. , Martinez-Sobrido Luis
Published: May 2023

Live-attenuated vaccines (LAVs) are able to induce robust immune responses, including both humoral and cellular immunity, representing a very promising option to provide broad and long-term immunity. To develop LAVs for SARS-CoV-2, we engineered attenuated recombinant SARS-CoV-2 (rSARS-CoV-2) that simultaneously lacks the viral open reading frame 3a (ORF3a) in combination with either ORF6, ORF7a, or ORF7b (Δ3a/Δ6, Δ3a/Δ7a, and Δ3a/Δ7b, respectively) proteins.
Exploring Molecular Interactions between Human Milk Hormone Insulin and Bifidobacteria
Authors: Rizzo Sonia Mirjam , Alessandri Giulia , Lugli Gabriele Andrea , Fontana Federico , Tarracchini Chiara , Mancabelli Leonardo , Viappiani Alice , Bianchi Massimiliano G. , Bussolati Ovidio , van Sinderen Douwe , Ventura Marco , Turroni Francesca
Published: May 2023

Breast milk is a key factor in modulating the infant's intestinal microbiota composition. Even though the interaction between human milk sugars and bifidobacteria has been extensively studied, there are other bioactive compounds in human milk that may influence the gut microbiota, such as hormones.
The Principles of SARS-CoV-2 Intervariant Competition Are Exemplified in the Pre-Omicron Era of the Colombian Epidemic
Authors: Orf Gregory S. , Pérez Lester J. , Ciuoderis Karl , Cardona Andrés , Villegas Simón , Hernández-Ortiz Juan P. , Baele Guy , Mohaimani Aurash , Osorio Jorge E. , Berg Michael G. , Cloherty Gavin A.
Published: May 2023

Before the appearance of the Omicron variant in late 2021, numerous SARS-CoV-2 variants emerged, were established, and declined, often with different outcomes in different geographic areas. In this study, we considered the trajectory of the Mu variant, which only successfully dominated the epidemic landscape of a single country: Colombia.
The Unprecedented Duration of the 2020 Ozone Depletion in the Antarctic
Authors: Zuev V. V. , Savelieva E. S. , Pavlinsky A. V. , Sidorovski E. A.
Published: May 2023

An increase in the duration of the period of high stability of the Antarctic polar vortex in late spring and early summer (November–December), which has been observed over the past 30 years, is observed. This trend is manifested both in the dynamics of the main characteristics of the polar vortex (vortex area and wind speed along the vortex boundary) and in the area of the Antarctic ozone hole. The dynamics of the polar vortex of 2020 is clear evidence of this phenomenon. During that time, unusually high wind speeds along the vortex boundary were recorded throughout the entire period of its existence; anomalous areas of the vortex and the ozone hole were observed from mid-November to December. In addition, the polar vortex existed until the last week of December, which is unprecedented. To analyze the dynamics of the Antarctic polar vortex, we used the method of vortex delineation on the basis of geopotential values, which were determined from the maximum temperature gradient and the maximum wind speed characterizing the boundaries of the vortex.
Retrieving the Angular Distribution of Sea Wave Energy according to Satellite Imagery Spectra
Authors: Bondur V. G. , Dulov V. A. , Kozub V. A. , Murynin A. B. , Yurovskaya M. V. , Yurovsky Yu. Yu.
Published: May 2023

The development of a method of retrieval of two-dimensional spatial spectra of sea wave elevations is proposed on the basis of high-resolution satellite imagery, which permits estimation of the angular distributions of wind wave energy. The method is validated by the results of a comprehensive experiment that involved satellite imaging of the Black Sea water area using optical instruments and sea truth measurements under controlled conditions from a stationary oceanographic platform. The angular distribution of sea wave energy retrieved by spatial spectra of satellite imagery fragments was compared with the results of measurements of the frequency-angular spectra collected using an array of string wave recorders. It is shown that the results of remote and in situ measurements are consistent in the range of sea wavelengths from 2.8 to 30 m and that the average absolute error is 0.3.
A Variety of Transformations of Nonlinear Internal Tidal Waves of the Northwestern Shelf of Australia
Authors: Holloway P. E. , Serebryany A. N.
Published: May 2023

Highly nonlinear internal waves at the continental margin on the northwestern shelf of Australia are discussed using detailed velocity and temperature time series recorded from moored current meters over 67 days. The region is characterized by a vigorous semidiurnal inland tide that propagates towards the shore along the shelf. In this area, an increase in the internal tide and the formation of bore-like formations, often accompanied by internal solitary waves, are observed. The frequency spectrum of the internal waves is presented, calculated from the records of the current component directed along the normal to the coast. Within the framework of this work, we have focused on analysis of the shape and properties of the internal tide. As a result, five different types of waves are distinguished. They consist of bores on the front or back sides of the wave, “square” waveforms with bores on both the front and back sides of the wave simultaneously, as well as small- and large-amplitude linear waves. The statistics of transformations of the types of internal tides during their propagation along the route section from the slope to the shelf is given. The main types of waves propagating without transformation and short-lived waves, which include “square” tidal waves and waves with bores on the back slope of the wave, are revealed. In general, the analysis provided an accurate account of the present-day nonlinear transformations of tidal internal waves on the Northwestern Australian Shelf.
U–Pb (ID-TIMS) Age of Garnet from Aillikites of the Kola Alkali Province
Authors: Stifeeva M. V. , Salnikova E. B. , Nosova A. A. , Kotov A. B. , Voznyak A. A. , Dimitrova D. A.
Published: May 2023

The U–Pb (ID-TIMS) geochronological studies of garnet from aillikites of the Kandalaksha dike swarm (Kola alkali province) were carried out. The estimated U–Pb age of garnet (374 ± 3 Ma) coincides with the major stage (373–377 Ma) of alkali magmatism in the Kola Province (LIP). Hence, it can be concluded that rocks of the dike complex of Kandalaksha Bay and foidolite-range rocks of alkali–ultrabasic massifs of this province were formed synchronously.
Changes in the care of acute cerebrovascular and cardiovascular conditions during the first year of the covid-19 pandemic in 746 hospitals in the USA: retrospective analysis
Authors: Nogueira Raul G , Etter Katherine , Nguyen Thanh N , Ikeme Shelly , Wong Charlene , Frankel Michael , Haussen Diogo C , Del Rio Carlos , McDaniel Michael , Sachdeva Rajesh , Devireddy Chandan M , Al-Bayati Alhamza R , Mohammaden Mahmoud H , Doheim Mohamed F , Pinheiro Agostinho C , Liberato Bernardo , Jillella Dinesh V , Bhatt Nirav R , Khanna Rahul
Published: May 2023

Objective

To measure the impact of the covid-19 pandemic on admissions to hospital and interventions for acute ischemic stroke and acute myocardial infarction.

Design

A retrospective analysis.

Setting

746 qualifying hospitals in the USA from the Premier Healthcare Database.

Participants

Patients aged 18 years and older who were admitted to hospital with a primary diagnosis of acute ischemic stroke or acute myocardial infarction between 1 March 2019 and 28 February 2021.

Main outcome measures

Relative changes in volumes were assessed for acute ischemic stroke and acute myocardial infarction hospital admissions as well as intravenous thrombolysis, mechanical thrombectomy, and percutaneous coronary intervention (overall and for acute myocardial infarction only) across the first year of the pandemic versus the prior year. Mortality in hospital and length of stay in hospital were also compared across the first year of the pandemic versus the corresponding period the year prior. These metrics were explored across the different pandemic waves.

Results

Among 746 qualifying hospitals, admissions to hospital were significantly reduced after the covid-19 pandemic compared with before the pandemic for acute ischemic stroke (−13.59% (95% confidence interval−13.77% to −13.41%) and acute myocardial infarction (−17.20% (−17.39% to −17.01%)), as well as intravenous thrombolysis (−9.47% (−9.99% to −9.02%)), any percutaneous coronary intervention (−17.89% (−18.06% to −17.71%)), and percutaneous coronary intervention for acute myocardial infarction (−14.36% (−14.59% to −14.12%)). During the first year of the pandemic versus the previous year, the odds of mortality in hospital for acute ischemic stroke were 9.00% higher (3.51%v3.16%; ratio of the means 1.09 (95% confidence interval (1.03 to 1.15); P=0.0013) and for acute myocardial infarction were 18.00% higher (4.81%v4.29%; ratio of the means 1.18 (1.13 to 1.23); P<0.0001).

Conclusions

We observed substantial decreases in admissions to hospital with acute ischemic stroke and acute myocardial infarction, but an increase in mortality in hospital throughout the first year of the pandemic. Public health interventions are needed to prevent these reductions in future pandemics.
Effect of early directed implementation of family-integrated care measures on colonisation withEnterobacteriaceaein preterm neonates in NICU
Authors: Parm Ülle , Tiit-Vesingi Annika , Soeorg Hiie , Štšepetova Jelena , Truusalu Kai , Vorobjov Sigrid , Lutsar Irja , Metsvaht Tuuli
Published: May 2023

Background

Hospital-acquired strains (HASs) and multiresistant strains in neonatal intensive care unit often harbour virulence and resistance mechanisms, carrying the risk of invasive infections. We describe colonisation withEnterobacteriaceaein neonates receiving early directed versus routine family-integrated care (FIC) within the first month of life.

Methods

A prospective cohort study included neonates with a gestational age below 34 weeks. During the first period, neonates were admitted to an open bay unit with transfer to the single-family room if available; feeding with the mother’s own breast milk (MOBM) was introduced within 24 hours, and skin-to-skin contact (SSC) within 5 days of life (the routine care group). During the second period, following a wash-in of 2 months, care in a single-family room within 48 hours, the introduction of MOBM within two and SSC in 48 hours were applied (the intervention group).Enterobacteriaceaeisolated from neonatal stool, breast milk and parental skin swabs were genotyped, Simpson’s Index of Diversity (SID) calculated, and extended-spectrum beta-lactamases (ESBL) detected.

Results

In 64 neonate-parents’ groups, 176Enterobacteriaceae, 87 in routine care and 89 in the intervention group were isolated; 26 vs 18 were HAS and one vs three ESBL positive, respectively. In the intervention group compared with the routine care group, SSC and MOBM feeding was started significantly earlier (p<0.001); during the first week of life, time spent in SSC was longer (median hours per day 4.8 (4–5.1) vs 1.9 (1.4–2.6), p<0.001) and the proportion of MOBM in enteral feeds was higher (median (IQR) 97.8% (95.1–100) vs 95.1% (87.2–97.4), p=0.011). Compared with the routine care group, the intervention group had higher SID and a reduction of HAS by 33.1% (95% CI 24.4% to 42.4%) in time series analysis.

Conclusions

Early implementation of FIC measures may hold the potential to increase diversity and reduce colonisation with HASEnterobacteriaceae.
Untangling risk factors including discipline-specific exposure for injuries in preprofessional and professional circus artists in the USA
Authors: Greenspan Stephanie , Stuckey Melanie I
Published: May 2023

Objective

This prospective cohort study quantified injury patterns related to specific circus discipline exposure in preprofessional and professional circus artists.

Methods

Circus artists (n=201; ages 13–69; 172 female, 29 male assigned sex at birth) were enrolled in 10 cities across the USA. Participants were followed for 1 year from enrolment, completing a weekly training log and undergoing a physical therapist evaluation for injuries. The circus-specific extension of the International Olympic Committee 2020 consensus on recording injury and illness in sports was used to analyse injury patterns.

Results

The study completion rate was 77% (n=155). Data were analysed by participant subgroup (age, professional status, sex at birth). The highest injury rates in participant subgroups were for males (5.69/1000 exposures) and related to discipline subgroups, were in aerial with ground elements (5.93/1000 exposures) and aerial (4.26/1000 exposures). Adults had more injuries related to aerial, whereas adolescents had more related to ground disciplines (χ2(2)=10.62, p=0.005) and non-time loss injuries (χ2(1)=5.45, p=0.02). Females had a higher proportion of repetitive injuries (70% vs 55%) than males (χ2(1) = 4.43, p=0.035). Individuals with an eating disorder history had more (p<0.004) injuries (mean 2.27±2.29) than those without (mean=1.48±0.96).

Conclusions

This study showed that intrinsic factors (age, sex at birth and history of eating disorder) and extrinsic factors (circus discipline exposure) affect injury risk. We need to account for the intersectionality of these factors to address risk management at an individual and group level.
Veterans’ experiences of moral injury, treatment and recommendations for future support
Authors: Bonson Amanda , Murphy D , Aldridge V , Greenberg N , Williamson V
Published: May 2023

Introduction

Moral injury (MI) significantly impacts the lives of many UK military veterans however, there is a lack of manualised treatment to address the needs of this population. To develop future treatments that are acceptable and well tolerated, veterans should be consulted on their experiences of existing psychological treatments and suggestions for future treatments.

Methods

10 UK military veterans were interviewed about their experiences of receiving treatment for psychological difficulties after MI, and beliefs about core components of future treatments. Thematic analysis of these interviews were conducted.

Results

2 superordinate themes were identified: experiences of previous mental health treatment and perceptions of the proposed treatments. Reflections on cognitive behavioural therapy were mixed, with some describing that it did not ameliorate their guilt or shame. In future treatments, focusing on values, using written letters and including therapy sessions with close companions were considered beneficial. Veterans reported that a strong rapport with therapist was key for MI treatment.

Conclusion

Findings provide a useful account of how current post-trauma treatments may be experienced by patients with MI. Although limited by sample size, the results highlight therapeutic approaches that may be helpful in future and provide important considerations for therapists treating MI.
Defence context for the UK’s Defence Engagement (Health)
Authors: Falconer Hall Thomas , Williams L G , Williams L , Horne S T
Published: May 2023

Defence Engagement (DE) has been a core UK Defence task since 2015. DE (Health) is the use of military medical capabilities to achieve DE effects within the health sector to achieve security and defence objectives. DE (Health) practitioners must understand the underlying defence context that shapes these objectives. The strategic context is becoming more uncertain with the return of great power competition layered on enduring threats from non-state actors and transnational challenges. The UK response has been to develop theIntegrated Review, outlining four national security and international policy objectives. UK Defence has responded by developing the integrated operating concept, differentiating military activity between operating and warfighting. Engage is one of the three functions of operate activity, which is complementary to the other operate functions of protect and constrain. DE (Health) can play a unique role in engagement, given its ability to develop new partnerships through health-related activity. DE (Health) may be an enabler for other engagements or to enable the protect and constrain functions. This will be dependent on delivering improvement in health outcomes. Therefore, the DE (Health) practitioner must be conversant with both the contemporary defence and global health contexts to deliver effective DE (Health) activities. This is an article commissioned for the DE special issue ofBMJ Military Health.
Continuous erector spinae plane catheters leading to unwanted neuraxial spread after spinal fusion surgery: a report of two cases from a terminated prospective randomized clinical trial
Authors: Amoroso Krizia , Hughes Alexander P , Sama Andrew A , Cammisa Frank P , Shue Jennifer , Soffin Ellen M
Published: May 2023

Background

Erector spinae plane blocks are used to improve outcomes after spine surgery, but pain frequently outlasts the duration of single injection blocks. We hypothesized continuous erector spinae plane (cESP) catheters would provide superior analgesia. We terminated a prospective double-blinded randomized clinical trial (RCT) comparing outcomes after multilevel spine surgery among patients randomized to saline versus ropivacaine cESP catheters. We present two cases of undesired epidural spread of ropivacaine and discuss etiology, management, and future research directions.

Case presentation

Nine out of 44 patients (planned) enrolled in the RCT; 6/9 were randomized to receive ropivacaine infusions via bilateral cESP catheters. Two patients underwent uncomplicated posterior lumbar fusion and were recovering well with minimal pain and opioid requirements through postoperative day 1. Both had new-onset urinary retention and bilateral lower extremity numbness, weakness and paresthesias (24 and 30 hours after infusion-start time, respectively). One patient underwent MRI, which was remarkable for an epidural fluid collection compressing the thecal sac. Infusions were stopped, cESP catheters were removed and symptoms fully resolved over the next 3–5 hours.

Conclusions

Unwanted neuraxial spread of local anesthetic from cESP catheters may be a unique consideration after spine surgery, accounted for by unpredictable local anesthetic distribution within disrupted surgical planes. Future studies are indicated to determine optimal catheter regimens together with guidance for extended monitoring in parallel with further studies of efficacy in spine surgery cohorts.

Trial registration number

NCT05494125.
Effects of hemodilution on coagulation function during prolonged hypotensive resuscitation in a porcine model of severe hemorrhagic shock
Authors: Neidert Leslie E , Morgan Clifford G , Hathaway Emily N , Hemond Peter J , Tiller Michael M , Cardin Sylvain , Glaser Jacob J
Published: May 2023

Background

Although hemorrhage remains the leading cause of survivable death in casualties, modern conflicts are becoming more austere limiting available resources to include resuscitation products. With limited resources also comes prolonged evacuation time, leaving suboptimal prehospital field care conditions. When blood products are limited or unavailable, crystalloid becomes the resuscitation fluid of choice. However, there is concern of continuous crystalloid infusion during a prolonged period to achieve hemodynamic stability for a patient. This study evaluates the effect of hemodilution from a 6-hour prehospital hypotensive phase on coagulation in a porcine model of severe hemorrhagic shock.

Methods

Adult male swine (n=5/group) were randomized into three experimental groups. Non-shock (NS)/normotensive did not undergo injury and were controls. NS/permissive hypotensive (PH) was bled to the PH target of systolic blood pressure (SBP) 85±5 mm Hg for 6 hours of prolonged field care (PFC) with SBP maintained via crystalloid, then recovered. Experimental group underwent controlled hemorrhage to mean arterial pressure 30 mm Hg until decompensation (Decomp/PH), followed by PH resuscitation with crystalloid for 6 hours. Hemorrhaged animals were then resuscitated with whole blood and recovered. Blood samples were collected at certain time points for analysis of complete blood counts, coagulation function, and inflammation.

Results

Throughout the 6-hour PFC, hematocrit, hemoglobin, and platelets showed significant decreases over time in the Decomp/PH group, indicating hemodilution, compared with the other groups. However, this was corrected with whole blood resuscitation. Despite the appearance of hemodilution, coagulation and perfusion parameters were not severely compromised.

Conclusions

Although significant hemodilution occurred, there was minimal impact on coagulation and endothelial function. This suggests that it is possible to maintain the SBP target to preserve perfusion of vital organs at a hemodilution threshold in resource-constrained environments. Future studies should address therapeutics that can mitigate potential hemodilutional effects such as lack of fibrinogen or platelets.

Level of evidence

Not applicable—Basic Animal Research.
Probing a $$\textrm{Z}^{\prime }$$ with non-universal fermion couplings through top quark fusion, decays to bottom quarks, and machine learning techniques
Authors: Barbosa Diego , Díaz Felipe , Quintero Liliana , Flórez Andrés , Sanchez Manuel , Gurrola Alfredo , Sheridan Elijah , Romeo Francesco
Published: May 2023

The production of heavy neutral mass resonances, $$\text {Z}^{\prime }$$

Z
′

, has been widely studied theoretically and experimentally. Although the nature, mass, couplings, and associated quantum numbers of this hypothetical particle are yet to be determined, current LHC experimental results have set strong constraints assuming the simplest beyond Standard Model (SM) hypotheses. We present a new feasibility study on the production of a $$\text {Z}^{\prime }$$

Z
′

boson at the LHC, with family non-universal couplings, considering proton–proton collisions at $$\sqrt{s} = 13$$

s

=
13

and 14 TeV. Such a hypothesis is well motivated theoretically and it can explain observed differences between SM predictions and experimental results, as well as being a useful tool to further probe recent results in searches for new physics considering non-universal fermion couplings. We work under two simplified phenomenological frameworks where the $$\textrm{Z}^{\prime }$$

Z
′

masses and couplings to the SM particles are free parameters, and consider final states of the $$\text {Z}^{\prime }$$

Z
′

decaying to a pair of $$\textrm{b}$$
b
quarks. The analysis is performed using machine learning techniques to maximize the sensitivity. Despite being a well motivated physics case in its own merit, such scenarios have not been fully considered in ongoing searches at the LHC. We note the proposed search methodology can be a key mode for discovery over a large mass range, including low masses, traditionally considered difficult due to experimental constrains. In addition, the proposed search is complementary to existing strategies.
Joint Neural Denoising of Surfaces and Volumes
Authors: Hofmann Nikolai , Hasselgren Jon , Munkberg Jacob
Published: May 2023

Denoisers designed for surface geometry rely on noise-free feature guides for high quality results. However, these guides are not readily available for volumes. Our method enables combined volume and surface denoising in real time from low sample count (4 spp) renderings. The rendered image is decomposed into volume and surface layers, leveraging spatio-temporal neural denoisers for both components. The individual signals are composited using learned weights and denoised transmittance. Our architecture outperforms current denoisers in scenes containing both surfaces and volumes, and produces temporally stable results at interactive rates.
Efficient Rendering for Light Field Displays using Tailored Projective Mappings
Authors: Fink Laura , Strobel Svenja , Franke Linus , Stamminger Marc
Published: May 2023

A standard paradigm when rendering for parallax-based light field displays is to render multiple, slightly offset views first and to interweave these afterwards. In practice, more than 40 views of preferably high resolution need to be rendered per frame to achieve acceptable visual quality. The total amount of rendered pixels may consequently exceed the native resolution of the display by far. Increased memory consumption and sub-optimal render times are direct consequences.

In this paper, we examine where pixels are "wasted" and present novel projective mappings for the virtual camera system that are custom tailored to such displays. Thus, we alleviate the aforementioned issues and show significant performance improvements regarding render time and memory consumption, while having only minor impact on visual quality. As we mainly touch the projective mapping of the virtual camera, our method is lean and can easily be integrated in existing rendering pipelines with minimal side effects.
Efficient Spatial Resampling Using the PDF Similarity
Authors: Tokuyoshi Yusuke
Published: May 2023

In real-time rendering, spatiotemporal reservoir resampling (ReSTIR) is a powerful technique to increase the number of candidate samples for resampled importance sampling. However, reusing spatiotemporal samples is not always efficient when target PDFs for the reused samples are dissimilar to the integrand. Target PDFs are often spatially different for highly detailed scenes due to geometry edges, normal maps, spatially varying materials, and shadow edges. This paper introduces a new method of rejecting spatial reuse based on the similarity of PDF shapes for single-bounce path connections (e.g., direct illumination). While existing rejection methods for ReSTIR do not support arbitrary materials and shadow edges, our PDF similarity takes them into account because target PDFs include BSDFs and shadows. In this paper, we present a rough estimation of PDF shapes using von Mises--Fisher distributions and temporal resampling. We also present a stable combination of our rejection method and the existing rejection method, considering estimation errors due to temporal disocclusions and moving light sources. This combination efficiently reduces the error around shadow edges with temporal continuities. By using our method for a ReSTIR variant that reuses shadow ray visibility for the integrand, we can reduce the number of shadow rays while preserving shadow edges.
G2 Blending Ball B-Spline Curve by B-Spline
Authors: Zhao Yuming , Wu Zhongke , Wang Xingce , Liu Xinyue
Published: May 2023

Blending two Ball B-Spline Curves(BBSC) is an important tool in modeling tubular objects. In this paper, we propose a new BBSC blending method. Our method has the following three main contributions: First, we use BBSC instead of ball Bézier to model the blending part to expand the solution space and make the resultant BBSC have better fairness. Second, we consider both the skeleton line and radius of BBSC, which makes the skeleton line and radius consistent. Thirdly, we propose a two-step optimization process to solve the problem of excessive amount of parameters brought by expanding the solution space, so that our method satisfies the real-time.
Unpaired Translation of 3D Point Clouds with Multi-part Shape Representation
Authors: Li Chih-Chia , Lin I-Chen
Published: May 2023

Unpaired shape translation is an emerging task for intelligent shape modelling and editing. Recent methods for 3D shape transfer use single- or multi-scale latent codes but a single generator to generate the whole shape. The transferred shapes are prone to lose control of local details. To tackle the issue, we propose a parts-to-whole framework that employs multi-part shape representation to preserve structural details during translation. We decompose the whole shape feature into multiple part features in the latent space. These part features are then processed by individual generators respectively and transformed to point clouds. We constrain the local features of parts within the loss functions, which enable the model to generate more similar shape characteristics to the source input. Furthermore, we propose a part aggregation module that improves the performance when combining multiple point clusters to generate the final output. The experiments demonstrate that our multi-part shape representation can retain more shape characteristics compared to previous approaches.
An Interactive Framework for Visually Realistic 3D Motion Synthesis using Evolutionarily-trained Spiking Neural Networks
Authors: Polykretis Ioannis , Patil Aditi , Aanjaneya Mridul , Michmizos Konstantinos
Published: May 2023

We present an end-to-end method for capturing the dynamics of 3D human characters and translating them for synthesizing new, visually-realistic motion sequences. Conventional methods employ sophisticated, but generic, control approaches for driving the joints of articulated characters, paying little attention to the distinct dynamics of human joint movements. In contrast, our approach attempts to synthesize human-like joint movements by exploiting a biologically-plausible, compact network of spiking neurons that drive joint control in primates and rodents. We adapt the controller architecture by introducing learnable components and propose an evolutionary algorithm for training the spiking neural network architectures and capturing diverse joint dynamics. Our method requires only a few samples for capturing the dynamic properties of a joint's motion and exploits the biologically-inspired, trained controller for its reconstruction. More importantly, it can transfer the captured dynamics to new visually-plausible motion sequences. To enable user-dependent tailoring of the resulting motion sequences, we develop an interactive framework that allows for editing and real-time visualization of the controlled 3D character. We also demonstrate the applicability of our method to real human motion capture data by learning the hand joint dynamics from a gesture dataset and using our framework to reconstruct the gestures with our 3D animated character. The compact architecture of our joint controller emerging from its biologically-realistic design, and the inherent capacity of our evolutionary learning algorithm for parallelization, suggest that our approach could provide an efficient and scalable alternative for synthesizing 3D character animations with diverse and visually-realistic motion dynamics.
Differentiable Curl-Noise
Authors: Ding Xinwen , Batty Christopher
Published: May 2023

We present Differentiable Curl-Noise, a C1 procedural method to animate strictly incompressible fluid flows in two dimensions. While both the original Curl-Noise method of Bridson et al. [2007] and a recent modification by Chang et al. [2022] have been used to design incompressible flow fields, they often suffer from non-smoothness in their handling of obstacles, owing in part to properties of the underlying Euclidean distance function or closest point function. We therefore propose a differentiable scheme that modulates the background potential in a manner that respects arbitrary solid simple polygonal objects placed at any location, without introducing discontinuities. We demonstrate that our new method yields improved flow fields in a set of two dimensional examples, including when obstacles are in close proximity or possess concavities.
NeRFahedron
Authors: Sin Zackary P. T. , Ng Peter H. F. , Leong Hong Va
Published: May 2023

Neural rendering is an exciting topic injecting machine learning methodologies into the classical computer graphics rendering pipeline. Although recent works have achieved remarkable fidelity, discussion on how to enable it for interactive scenarios like video games seems to be lacking. Aside from an editable 3D model and UV-mapping, an interactive application will demand the neural rendering to handle animatable 3D content with interactive speed. This is currently a gap in neural rendering and our solution to this problem is a novel neural rendering pipeline involving a primitive named NeRFahedron. It localizes a NeRF field and as such effectively reduces the number of expensive network sampling operations to improve speed. Our pipeline involves tetrahedron rasterization, localized ray marching and near-surface particle sampling. The result is a method that can enable animatable content for neural rendering with interactive speed, which has been shown to be competitive in rendering animation. We will also showcase its ability to enable interactive applications via a real-time demo.
Eye-Based Point Rendering for Dynamic Multiview Effects
Authors: Gavane Ajinkya , Watson Benjamin
Published: May 2023

Eye-based point rendering (EPR) can make multiview effects much more practical by adding eye (camera) buffer resolution efficiencies to improved view-independent rendering (iVIR). We demonstrate this very successfully by applying EPR to dynamic cube-mapped reflections, sometimes achieving nearly 7× speedups over iVIR and traditional multiview rendering (MVR), with nearly equivalent quality. Our application to omnidirectional soft shadows is less successful, demonstrating that EPR is most effective with larger shader loads and tight eye buffer to off-screen (render target) buffer mappings. This is due to EPR's eye buffer resolution constraints limiting points and shading calculations to the sampling rate of the eye's viewport. In a 2.48 million triangle scene with 50 reflective objects (using 300 off-screen views), EPR renders environment maps with a 49.40ms average frame time on an NVIDIA 1080 Ti GPU. In doing so, EPR generates up to 5x fewer points than iVIR, and regularly performs 50× fewer shading calculations than MVR.
A Digital Collaborative Platform for the Silver Economy: Functionalities Required by Stakeholders in a Multinational Baltic Sea Region Project
Authors: Butt Sidra Azmat , Suran Shweta , Pappel Ingrid , Smærup Michael , Krimmer Robert , Draheim Dirk
Published: May 2023

This article develops functionalities for a digital collaborative platform, called the Digital Silver Hub, which aims to serve as an ecosystem for the quadruple helix actors (private sector, public sector, academic institutions, and senior citizens) to participate in knowledge exchange, collaboration, and co-creation of innovative technological solutions to facilitate the elderly population. In service of that, we have conducted 30 interviews from the partner heads of an EU-funded project as well as quadruple helix actors from each region in the Baltic Sea Region (Estonia, Latvia, Finland, Lithuania, Denmark, and St. Petersburg) to deeply understand the functionalities that are needed to be offered by the platform. A deductive thematic analysis has been conducted to analyse these functionalities in terms of collective intelligence (CI) components (namely staffing, processes, goals, and motivation) based on a most recent generic CI model. The functionalities were further evaluated by experts working in the field of science and technology in the silver economy. Overall, this article offers insights into the functionalities that are required for a digital collaborative platform to support the elderly population and facilitate co-creation among quadruple helix actors, as well as provides a foundation for future work on designing and implementing such a platform.
Improved ventilation efficiency due to continuous gas flow compared to decelerating gas flow in mechanical ventilation: results of a porcine trial
Authors: Abram Julia , Spraider Patrick , Mathis Simon , Wagner Julian , Ranalter Manuela , Putzer Gabriel , Glodny Bernhard , Hell Tobias , Barnes Tom , Enk Dietmar , Martini Judith
Published: May 2023

This study examined the effects of a continuous (flow-controlled ventilation, FCV) vs. decelerating (pressure-controlled ventilation, PCV) gas flow pattern during mechanical ventilation. It was shown that FCV necessitates a lower alveolar pressure amplitude leading to reduced applied tidal volumes and consequently minute volume. Notwithstanding these differences, CO2-removal as well as oxygenation was not inferior in FCV compared with PCV, which is suggestive of improved gas exchange efficiency at a continuous gas flow pattern.