bluuebunny/crossref_metadata_2025 huggingface dataset:
One-Way Valve Malfunction in an Extracorporeal Membrane Oxygenation Priming Circuit
Authors: Ellis W. Cory , Butler Katie , Campbell David , Barrett Cindy , Buckvold Shannon
Published: July 2023

Developing technologies have changed both the components and the management style when extracorporeal membrane oxygenation (ECMO) is used to support critically ill cardiac and respiratory patients. The Cardiohelp system™ is a small, portable extracorporeal system just recently available within the United States. Manufacturing standards and quality processes have made mechanical failure and malfunction of extracorporeal components less common; however, there is still potential for mechanical failure or component malfunction before or during extracorporeal support. This case review describes the malfunction of a Retroguard™ unidirectional flow valve integrated into the priming setup of a Cardiohelp system™ during the priming process.
Peritoneal Dialysis: An Alternative Modality of Fluid Removal in Neonates Requiring Extracorporeal Membrane Oxygenation after Cardiac Surgery
Authors: Sasser William C. , Robert Stephen M. , Askenazi David J. , O’Meara L. Carlisle , Borasino Santiago , Alten Jeffrey A.
Published: July 2023

Extracorporeal membrane oxygenation (ECMO) is a lifesaving therapy for patients with cardiopulmonary failure after cardiac surgery. Fluid overload (FO) is associated with increased morbidity and mortality in this population. We present our experience using peritoneal dialysis (PD) as an adjunct for fluid removal in eight consecutive neonates requiring ECMO after cardiac surgery between 2010 and 2012. PD was added to FO management when fluid removal goals were not being met by hemofiltration (HF) or hemodialysis (HD). Percent FO was 36% at ECMO initiation; 88% (seven of eight) achieved negative fluid balance before discontinuation of ECMO. PD removed median 119 mL/kg/day (interquartile range [IQR], 70–166) compared with median 132 mL/kg/day (IQR, 47–231) removed by HF/HD. PD and HF/HD fluid removal were performed concurrently 38% of the time. Unlike HF/HD, PD was never stopped secondary to hemodynamic compromise. Median duration of ECMO was 155 hours (IQR, 118–215). Six of eight patients were successfully decannulated. These results suggest PD safely and effectively removes fluid in neonates on ECMO after cardiac surgery. PD may increase total fluid removal potential when combined with other modalities.
Contemporary Oxygenator Design Relative to Hemolysis
Authors: Venema Leonie H. , Sharma Ajay S. , Simons Antoine P. , Bekers Otto , Weerwind Patrick W.
Published: July 2023

Hemolysis is a well-known phenomenon during cardiovascular surgery and generally attributed to cardiopulmonary bypass, particularly when using high-resistant oxygenators. This study aimed at investigating whether transoxygenator pressure drop can be considered an independent factor of hemolysis. Additionally, intraoxygenator blood distribution and shear stress were assessed. A low-resistant (LR, n = 3), a moderate-resistant (MR, n = 3), and a high-resistant (HR, n = 3) clinically used membrane oxygenator were tested in vitro using a roller pump and freshly drawn heparinized porcine blood. Flow rates were set to 2 and 4 L/min and maximum flow compliant to the oxygenator type for 1 hour each. As a control, the oxygenator was excluded from the system. Blood samples were taken every 30 minutes for plasma-free hemoglobin assay and transoxygenator pressure was measured inline. Intraoxygenator blood distribution was assessed using an ultrasound dilution technique. Despite the relatively broad spectrum of pressure drop and resultant transoxygenator pressure drops (LR: 14–41 mmHg, MR: 29–115 mmHg, HR: 77–284 mmHg, respectively), no significant association (R2 = .074, p = .22) was found with the normalized index of hemolysis. The shear stress of each oxygenator at maximum flow rate amounted to 3.0 N/m2 (LR), 5.7 N/m2 (MR), and 8.4 N/m2 (HR), respectively. Analysis of blood flow distribution curves (kurtosis and skewness) revealed intraoxygenator blood flow distribution to become more homogeneous when blood flow rates increased. Contemporary oxygenators were shown not to be a predominant factor for red blood cell damage.
Factor XII Deficiency and Cardiopulmonary Bypass
Authors: Uppal Victor , Rosin Mark
Published: July 2023

Factor XII deficiency is a laboratory finding in patients who normally do not present with bleeding tendencies. This deficiency is important in the patient undergoing cardiopulmonary bypass because activated clotting times are not helpful in determining proper levels of heparin anticoagulation and its reversal. We present a case of a patient with factor XII deficiency that had coronary artery bypass grafting and cardiopulmonary bypass using heparin for anticoagulation. Cardiopulmonary bypass was successfully carried out by monitoring heparin concentration ensuring adequate heparinization during the procedure. Results from activated clotting time, heparin dose–response, and heparin protamine titration are given. Heparin anticoagulation in patients with factor XII deficiency can be safely carried out with heparin concentration monitoring.
Safety Testing of Left Ventricular Vent Valves
Authors: Gavin Caroline , Coblentz John , Acsell Jeffrey R. , Shackelford Anthony G. , Sistino Joseph J.
Published: July 2023

Vent vacuum relief valves (VRVs) are used to limit the negative pressure at the ventricular vent catheter tip as well as prevent reversal of blood flow and prevention of air embolism. The purpose of this study was to evaluate the performance of three commercially available ventricular vent valves. The negative pressure at which the vent valve opened was measured at the valve inlet using high-fidelity pressure transducers. Also, the flow rate at which air entrainment occurred due to valve opening was recorded. Using a 51.5 cm column of saline, the resistance for each valve was calculated. The mean ± SD opening negative pressures were −231.3 ± 35.2 mmHg for the Quest Medical valve, −219.8 mmHg ± 17.2 for the Sorin valve, and −329.6 ± 38.0 mmHg for the Terumo valve. The red Quest Medical valve opened at a lower flow (1.44 ± .03 L/min) than the dark blue Sorin valve (2.93 ± .01 L/min) and light blue LH130 Terumo valve (2.36 ± .02 L/min). The Sorin valve had the least resistance of 34.1 dyn·s/cm5, followed by the Terumo LH130 valve resistance of 58.1 dyn·s/cm5, and the Quest Medical VRV-II valve with a resistance of 66.5 dyn·s/cm5. We found that the valves are significantly different in the negative pressure generated. Understanding the limitations of these devices is important to reduce the occurrence of adverse events associated with venting and to select the best device for a specific clinical application.
Impact of Intraoperative Events on Cerebral Tissue Oximetry in Patients Undergoing Cardiopulmonary Bypass
Authors: Ševerdija Ervin E. , Vranken Nousjka P.A. , Teerenstra Steven , Ganushchak Yuri M. , Weerwind Patrick W.
Published: July 2023

Previous studies showed that decreased cerebral saturation during cardiac surgery is related to adverse postoperative outcome. Therefore, we investigated the influence of intraoperative events on cerebral tissue saturation in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). A total of 52 adult patients who underwent cardiac surgery using pulsatile CPB were included in this prospective explorative study. Cerebral tissue oxygen saturation (SctO2) was measured in both the left and right cerebral hemisphere. Intraoperative events, involving interventions performed by anesthesiologist, surgeon, and clinical perfusionist, were documented. Simultaneously, in-line hemodynamic parameters (partial oxygen pressure, partial carbon dioxide pressure, hematocrit, arterial blood pressure, and CPB flow rates) were recorded. Cerebral tissue saturation was affected by anesthetic induction (p < .001), placement of the sternal retractor (p < .001), and initiation (p < .001) as well as termination of CPB (p < .001). Placement (p < .001) and removal of the aortic cross-clamp (p = .026 for left hemisphere, p = .048 for right hemisphere) led to changes in cerebral tissue saturation. In addition, when placing the aortic cross-clamp, hematocrit (p < .001) as well as arterial (p = .007) and venous (p < .001) partial oxygen pressures changed. Cerebral tissue oximetry effectively identifies changes related to surgical events or vulnerable periods during cardiac surgery. Future studies are needed to identify methods of mitigating periods of reduced cerebral saturation.
Performance and Safety of an Integrated Portable Extracorporeal Life Support System for Adults
Authors: Alwardt Cory M. , Wilson Donald S. , Alore Michelle L. , Lanza Louis A. , DeValeria Patrick A. , Pajaro Octavio E.
Published: July 2023

Extracorporeal membrane oxygenation (ECMO) is indicated when conventional measures fail to support a patient during cardiac or respiratory failure. Due to the complicated nature of ECMO, patients often require transport to a tertiary care center. This study retrospectively compared the performance of the Cardiohelp™ (Maquet) life support system with a previously used ECMO circuit when transporting adult patients on venoarterial ECMO between facilities. Two ECMO circuits were compared for performance: 1) the Cardiohelp™ (Maquet) life support system and 2) the “standard” circuit consisting of a Thoratec CentriMag centrifugal pump, Maquet Quadrox-D oxygenator, and a Terumo CDI-500 in-line blood gas analyzer. After analyzing data from 16 patients (eight patients supported with each ECMO system), no differences in patient demographics, percentage of patients successfully weaned from ECMO, percentage of patients surviving to discharge, duration supported on the initial ECMO system, or total duration of ECMO were noted. No patient deaths were related to circuit failure or circuit disruptions in either group. Analysis of the performance of the ECMO circuits and the resulting patient status showed few significant differences between ECMO groups (Cardiohelp™ vs. standard circuit) and time points (the first 8 hours vs. a 24-hour time point). The statistically significant differences were not concerning in terms of appropriate medical support or patient safety. Of interest, the transmembrane pressure was significantly lower for the Cardiohelp™ module vs. the standard oxygenator during the first 8 hours (20.1 [5.3] vs. 37.1 [7.1] mmHg;p< .001) and at 24 hours (21.3 [3.8] vs. 34.8 [7.9] mmHg;p= .001). The Cardiohelp™ portable life support system provides safe and reliable support for adult patients on ECMO during interhospital patient transport as compared to the standard circuit.
Variability in End-Organ Perfusion with Femoral-Femoral Venoarterial Extracorporeal Membrane Oxygenation: Aortographic Evidence
Authors: de Biasi Andreas R. , DeBois William J. , Kim Luke , Salemi Arash
Published: July 2023

In femoral-femoral venoarterial extracorporeal membrane oxygenation (VA-ECMO), the outflow of oxygenated blood from the circuit enters the aorta in retrograde fashion. As a result, variability in end-organ oxygenation (e.g., cerebral vs. splanchnic) may arise—particularly, when the heart is unable to contribute forward flow. We present the case of a 74-year-old man supported by femoral-femoral VA-ECMO in whom aortography was used to visualize the retrograde distribution of arterial ECMO flow that can produce such differences in end-organ perfusion. We do this by describing a series of still images captured during the aortography; we then discuss the importance of monitoring end-organ oxygenation in this setting and outline several interventions that can ameliorate this flow phenomenon.
Special Report
Authors: Likosky Donald S. , Baker Robert A. , Dickinson Timothy A. , FitzGerald Daniel J. , De Somer M. Filip , Groom Robert C. , Fitzgerald David , Shann Kenneth G. , Poullis Michael , Spiess Bruce D. , Jabr Karim , Lucas Mark T. , Ferguson James D. , Bronson Shahna L.
Published: July 2023

Gaps remain in our understanding of the contribution of bypass-related practices associated with red blood cell (RBC) transfusions after cardiac surgery. Variability exists in the reporting of bypass-related practices in the peer-reviewed literature. In an effort to create uniformity in reporting, a draft statement outlining proposed minimal criteria for reporting cardiopulmonary bypass (CPB)-related contributions (i.e., RBC data collection/documentation, clinical considerations for transfusions, equipment details, and clinical endpoints) was presented in conjunction with the American Society of ExtraCorporeal Technology’s (AmSECT’s) 2014 Quality and Outcomes Meeting (Baltimore, MD). Based on presentations and feedback from the conference, coauthors (n= 14) developed and subsequently voted on each proposed data element. Data elements receiving a total of ≤4 votes were dropped from further consideration, 5–9 votes were considered as “Recommended,” and elements receiving ≥10 votes were considered as “Mandatory.” A total of 52 elements were classified as mandatory, 16 recommended, and 14 dropped. There are 8 mandatory data elements for RBC data collection/documentation, 24 for clinical considerations for transfusions, 13 for equipment details, and 7 for clinical endpoints. We present 52 mandatory data elements reflecting CPB-related contributions to RBC transfusions. Consistency of such reporting would offer our community an increased opportunity to shed light on the relationship between intra-operative practices and RBC transfusions.
The History of Goal-Directed Therapy and Relevance to Cardiopulmonary Bypass
Authors: Dijoy Laurie , Dean John Scott , Bistrick Carla , Sistino Joseph J.
Published: July 2023

Goal-directed therapy is a patient care strategy that has been implemented to improve patient outcomes. The strategy includes aggressive patient management and monitoring during a period of critical care. Goal-directed therapy has been adapted to perfusion and has been designated goal-directed perfusion (GDP). Since this is a new concept in perfusion, the purpose of this study is to review goal-directed therapy research in other areas of critical care management and compare that process to improving patient outcomes following cardiopulmonary bypass. Various areas of goal-directed therapy literature were reviewed, including fluid administration, neurologic injury, tissue perfusion, oxygenation, and inflammatory response. Data from these studies was compiled to document improvements in patient outcomes. Goal-directed therapy has been demonstrated to improve patient outcomes when performed within the optimal time frame resulting in decreased complications, reduction in hospital stay, and a decrease in morbidity. Based on the successes in other critical care areas, GDP during cardiopulmonary bypass would be expected to improve outcomes following cardiac surgery.
Use of a Modified Cardiopulmonary Bypass Circuit for Suction Embolectomy with the AngioVac Device
Authors: Michelson Cara M. , Dyke Cornelius M. , Wick Douglas J. , Guenther Rory , Dangerfield Dylan , Wiisanen Matthew E.
Published: July 2023

The AngioVac suction cannula and circuit were designed for the percutaneous removal of soft thrombus and emboli in procedures requiring extracorporeal circulatory support. We describe a modification of the AngioVac suction catheter and cardiopulmonary bypass (CPB) circuit to effectively remove thrombus while maintaining the ability to rapidly initiate full CPBs during a medical crisis. This article will discuss the design concepts of the modified circuit as well as procedural protocols and considerations. The design modifications of incorporating an oxygenator, reservoir, and bridge allow for an increased flexibility that allows adaption to veno-venous extracorporeal membrane oxygenation or full CPB support when required for oxygenation or hemodynamic support.
Self-limited Familial Neonatal Epilepsy due to the c.1589G > A Novel Pathogenic Variant in KCNQ2: A Family Report
Authors: Basarir Gunce , Ozer Kaya Ozge , Kusgoz Fatma , Olgac Dundar Nihal , Gencpinar Pinar
Published: July 2023

Self-limited familial neonatal epilepsy is an autosomal dominant epileptic syndrome characterized by episodes of seizures occurring in the first days of life. Most patients have heterozygous mutations of KCNQ2 gene located on 20q13. A variety of clinical phenotypes have been associated with KCNQ2 mutations, making the prediction of this rare entity difficult. Herein, we report a rare KCNQ2 variant in two siblings with self-limited familial neonatal epilepsy. The siblings had tonic seizures accompanied by clonic jerks in the first few days after birth. Genetic analysis of the siblings revealed a heterozygous KCNQ2 variant: c.1589G > A; (p.Ser530Asn). The identical variant subsequently was identified in the mother. To our knowledge, this variant has not been previously reported in individuals with KCNQ2-related disease. This is the first report that reveals c.1589G > A variant of KCNQ2 gene as a pathogenic variant in two siblings.
Non-COVID-19 Cutaneous Mucormycosis from a Plastic Surgical Perspective
Authors: Brajesh Vimalendu , Sharma Sneha , Aggarwal Aditya , Singh Sukhdeep , Mahendru Sanjay , Singh Hardeep , Jain Ankit , Jain Rahul , Khazanchi Rakesh Kumar
Published: July 2023

Background Cutaneous mucormycosis is a rare and fulminant infection associated with high mortality. Plastic surgeons come across this infection in the settings of road traffic accidents, surgical site infections, and as a secondary infection with underlying bacterial soft tissue infections. Due to this infection's rarity and aggressive course, it is essential to initiate prompt multidisciplinary management at the first presentation. With this study, we aim to present a protocol for managing the condition.

Methods This is a retrospective observational study of patients with cutaneous mucormycosis managed at a tertiary care hospital from January 1, 2016 to November 30, 2022 excluding patients with mucormycosis who tested positive for coronavirus disease 2019.

Results Of 24 patients, 22 were males, and most were in the age group of 41 to 60 years. Sixteen patients survived and five out of eight deceased had comorbidities, six presented primarily without prior debridement, and six had trunk involvement.

Conclusion A high index of clinical suspicion is necessary for early diagnosis and management of patients with invasive cutaneous mucormycosis. A multidisciplinary approach with appropriate medical and surgical management can improve outcomes in cases that otherwise carry a high mortality rate.
DNM1L Variant Presenting as Adolescent-Onset Sensory Neuronopathy, Spasticity, Dystonia, and Ataxia
Authors: Wang Alexander S. , Lemire Gabrielle , VanNoy Grace E. , Austin-Tse Christina , O'Donnell-Luria Anne , Kilbane Camilla
Published: July 2023

DMN1L encodes for dynaminlike protein 1 (DLP1), which plays a key role in peroxisomal and mitochondrial fission. Individuals with heterozygous variants in DNM1L present with a wide range of neurologic symptoms, including encephalopathy, epilepsy, and motor deficits. Here we report on a woman presenting with adolescence onset of sensory neuronopathy, spasticity, dystonia, and ataxia. Trio genome sequencing identified a heterozygous variant in DNM1L (NM_012062.3 c.121G > A/p.Val41Met), which was thought to be pathogenic. This case describes the latest known symptomatic onset of DMN1L-related disease described in the literature. We highlight our approach to a challenging diagnostic workup and interpretation of a specific variant that has not been previously reported. Furthermore, the case highlights the diagnostic importance of utilizing genomic sequencing and research studies for patients with rare disease.
Identification of Plasma Thrombopoietin Level and Its Significance in Patients with Aplastic Anemia and Myelodysplastic Syndrome
Authors: Zhang Mengying , Zhang Gaochao , Xu Fangfang , Liu Mengyuan , Dong Xifeng , Qi Weiwei , Wang Huaquan
Published: July 2023

Objective Our objective was to investigate the concentration of plasma thrombopoietin (TPO) in patients with aplastic anemia (AA) and myelodysplastic syndrome (MDS), as well as its relationship with patients' responses to recombined human TPO (rhTPO) therapy.

Methods We detected the concentration of plasma TPO in 31 patients with AA, 27 patients with MDS, and 11 normal controls using enzyme-linked immunosorbent assay.

Results The median concentration of plasma TPO in patients with AA, MDS, and controls was (841.08 ± 768.64), (212.41 ± 338.93), and (35.09 ± 18.21) pg/mL, respectively. The TPO concentration in patients with AA and MDS was significantly higher than that in controls (p < 0.05). The median platelet (PLT) counts were (184 ± 34) ×109/L in the control group and (24 ± 19) ×109/L and (80 ± 71) ×109/L in AA and MDS patients, respectively. Negative correlations were found between plasma TPO concentration and PLT counts as well as megakaryocytes in bone marrow (p < 0.05). In AA patients treated with rhTPO, a negative correlation was observed between increased PLT counts and pretreatment TPO levels (p < 0.05).

Conclusion Plasma TPO concentration in AA and MDS was significantly higher than that in normal controls. Plasma TPO was negatively correlated with peripheral blood PLT counts and bone marrow megakaryocyte counts. The pretreatment TPO level may serve as a prognostic indicator for the therapeutic effect of rhTPO in AA patients.
TWIST1 Gene Variants Cause Craniosynostosis with Limb Abnormalities in Asian Patients
Authors: Dhiman Shalini , Panigrahi Inusha , Sharma Maryada , Chaudhry Chakshu , Garg Mahak
Published: July 2023

The TWIST1 gene codes for a highly conserved transcription factor in a basic helix–loop–helix transcription factors family. The pattern of inheritance is autosomal dominant in Saethre–Chotzen syndrome, Robinow–Sorauf syndrome, and Sweeney–Cox syndrome. Major features of these syndromes include coronal synostosis, vision problems, and deafness, and facial features include hypertelorism, low-set ears, arched eyebrows, beaked nose, maxillary hypoplasia, and other dysmorphisms including broad great toes, clinodactyly, brachydactyly, and cutaneous syndactyly. TWIST1 (bHLH) transcription factor regulates the formation of head and limbs in the embryo. We describe three families affected with craniosynostosis in whom a sporadic TWIST1 variant was identified on whole exome sequencing, chromosomal microarray, and Sanger sequencing.
Electron circular dichroism in hot electron emission from metallic nanohelix arrays
Authors: Nürenberg Daniel , Mark Andrew G. , Fischer Peer , Zacharias Helmut
Published: July 2023

We investigate the electron emission from 3D chiral silver alloy nanohelices initiated by femtosecond laser pulses with a central photon energy of hν = 1.65 eV, well below the work function of the material. We find hot but thermally distributed electron spectra and a strong anisotropy in the electron yield with left- and right-circularly polarized light excitations, which invert in sign between left- and right-handed helices. We analyze the kinetic energy distribution and discuss the role of effective temperatures. Measurements of the reflectance and simulations of the absorbance of the helices based on retarded field calculations are compared to the anisotropy in photoemission. We find a significant enhancement of the anisotropy in the electron emission in comparison to the optical absorption. Neither simple thermionic nor a multiphoton photoemission can explain the experimentally observed asymmetries. Single photon deep-UV photoemission from these helices together with a change of the work function suggests a contribution of the chirally induced spin selectivity effect to the observed asymmetries.
The near-room-temperature upsurge of electrical resistivity in Lu-H-N is not superconductivity, but a metal-to-poor-conductor transition
Authors: Peng Di , Zeng Qiaoshi , Lan Fujun , Xing Zhenfang , Ding Yang , Mao Ho-kwang
Published: July 2023

The recent report of superconductivity in nitrogen-doped lutetium hydride (Lu-H-N) at 294 K and 1 GPa brought hope for long-sought-after ambient-condition superconductors. However, the failure of scientists worldwide to independently reproduce these results has cast intense skepticism on this exciting claim. In this work, using a reliable experimental protocol, we synthesized Lu-H-N while minimizing extrinsic influences and reproduced the sudden change in resistance near room temperature. With quantitative comparison of the temperature-dependent resistance between Lu-H-N and the pure lutetium before reaction, we were able to clarify that the drastic resistance change is most likely caused by a metal-to-poor-conductor transition rather than by superconductivity. Herein, we also briefly discuss other issues recently raised in relation to the Lu-H-N system.
Pittosporum (Pittosporaceae) in Malesia and Papuasia
Authors: Cayzer Lindy W. , Utteridge Timothy M. A. , Chandler Gregory T.
Published: July 2023

Pittosporum (Pittosporaceae, Apiales), an attractive genus of horticulturally important trees and shrubs, is revised for Malesia (Malaysia, Singapore, Indonesia, Brunei Darussalam, the Philippines, Timor-Leste) and Papuasia (Papua Barat (Indonesia), Papua New Guinea and the Solomon Islands). In this report, 52 species are recognised, including many species reinstated from synonymy. Three taxa are raised to species rank (P. owenstanleyense, P. patelliplacenta and P. purpurascens), one is a new combination in Pittosporum (P. impressum), and four new species are described: P. sulawesiense, P. isolatum, P. schoddei and P. sogeriense.
A first-principles study of MgSnN2 films using a DFT-1/2 approach
Authors: Chen Kai , Li Li , Chang Xiangrong , Hu Chunfeng , Feng Qingguo
Published: July 2023

The thin films of a newly discovered MgSnN2
Pnma phase were computationally investigated using a recently developed DFT-1/2 functional. It was showing that the properties of the investigated films closely relate to the thickness. For those films with odd number of layers, the band gaps are accordingly 2.040 eV, 2.102 eV and 2.107 eV for three, five and seven layers, showing an increasing order along with depth. As for those with even number of layers, the band gaps show a reduction from 2.488 eV for double layer to 2.210 eV for four-layer and then to 2.136 eV for six-layer. The change of the band gap mainly comes from the intralayer and interlayer bonding relation. The valence and conduction band edges increase monotonically along with the number of layers of thin films, except for the conduction band edge of double layer. Moreover, the absorption spectra shows promising absorption peaks within visible range. Therefore, fabrication of films with thickness control can potentially be used to expand the applications of MgSnN2 for energy harvest, photocatalysis, electronic and optoelectronic devices.
Effect of memristor’s potentiation-depression curves peculiarities in the convergence of physical perceptrons
Authors: Quiñonez Walter , Sánchez María José , Rubi Diego
Published: July 2023

Neuromorphic computing aims to emulate the architecture and information processing mechanisms of the mammalian brain. This includes the implementation by hardware of neural networks. Oxide-based memristor arrays with cross-bar architecture appear as a possible physical implementation of neural networks. In this paper, we obtain experimental potentiation-depression (P-D) curves on different manganite-based memristive systems and simulate the learning process of perceptrons for character recognition. We analyze how the specific characteristics of the P-D curves affect the convergence time -characterized by the EPOCHs-to-convergence (ETC) parameter- of the network. Our work shows that ETC is reduced for systems displaying P-D curves with relatively low granularity and non-linear and asymmetric response. In addition, we also show that noise injection during the synaptic weight actualization further reduces the ETC. The results obtained here are expected to contribute to the optimization of hardware neural networks based on memristors cross-bar arrays.
Quantitative comparison of impurity transport in turbulence reduced and enhanced scenarios at Wendelstein 7-X
Authors: Alcusón J.A. , Wegner Th. , Dinklage A. , Langenberg A. , Bähner J.-P. , Buttenschön B. , Edlund E.M. , Fuchert G. , García-Regaña J.M. , Grulke O. , Huang Z. , Porkolab M. , Stechow A.V. , Xanthopoulos P. , Zocco A.
Published: July 2023

We assess the turbulent particle transport being responsible for the limitation of the confinement and, thus, the overall performance of the neoclassically optimized stellarator Wendelstein 7-X. The radial particle transport is experimentally inferred from the evaluation of impurity injection into turbulence reduced and enhanced plasma scenarios revealing a completely different confinement behavior. The impact of the density gradient on the turbulent ion transport is theoretically estimated using large-scale non-linear gyro-kinetic simulations enabling, for the first time in Wendelstein 7-X, a quantitative comparison to the experimentally assessed impurity transport properties. We demonstrate that impurity transport in most of the Wendelstein 7-X discharges, up to now impossible to cover only with neoclassical estimations, is dominated by turbulence and can be modelled via gyro-kinetic simulations.
Deep multi-similarity hashing technique based on multi-label semantics
Authors: Cui Lichao , Bi Yuyang , Liu Mingxin
Published: July 2023

A deep multi-similarity hashing technique based on multi-label semantics has been proposed in this paper as a means of a new controlled deep hashing system for multi-label image retrieval. Our proposed methodology comprises hash code learning and semantically-aware similarity matrix creation. To create a similarity matrix that considers semantic context, we integrate label-level and semantic-level similarity. Using the higher-order statistics of deep features as inputs, we meticulously craft the multi-similarity loss and quantization error loss for hash code learning, ensuring that the learned binary codes retain their high-ranking similarity. Our suggested strategy is successful, as shown by several testing on CIFAR-10 and NUS-WIDE.
Broadcast Attention Learning for Real Telephone Speech Keyword Spotting
Authors: Ke Dengfeng , Du Baole , Tong Yunjia , Xu Yanyan
Published: July 2023

With the development of mobile smart devices, keyword spotting plays an important role in the interaction between machines and users. However, low storage and low energy consumption of mobile devices limit the accuracies of keyword spotting tasks. Therefore, how to achieve a balance between the high accuracy and low consumption is a research hotspot for a keyword spotting system. Convolutional neural networks have been widely adopted in recent keyword spotting systems due to their superior accuracies, and the success of the transformer architecture in many areas demonstrates the effectiveness of self-attention. In this paper, we combine self-attention and convolutional neural networks, and propose the broadcast attention learning network (BA-net), using a small number of parameters while achieving the accuracies of 97.18% and 78.44% respectively on the Google speech command dataset and a real telephone speech dataset.
Learning-Based UAV Coverage-Aware Path Planning in Large-scale Urban Environments
Authors: Shi Zhiyi , Huang Mengxing , Wu Di , Feng Zikai
Published: July 2023

In our research, the coverage-aware path planning problem of unmanned aerial vehicles (UAVs) in large-scale urban environments is studied. The goal of our research is to train the intelligent UAV to autonomously cover the area with satisfactory communication quality and finally arrive at the objective place without colliding with numerous skyscrapers. Such a multi-objective path planning problem is regularly non-convex and thus hard to converge. To this end, a distributed deep reinforcement learning (DRL)-based approach called Distributed-RPPO is developed to address the problem. To be specific, firstly we formulate our proposed problem as a Markov decision process (MDP). Since communication connectivity is the core constraint, a proximal policy optimization (PPO)-based SIR prediction network is designed for guiding the UAV to cover the area with superior communication connectivity, using only the UAV’s current location. Then we combine the PPO algorithm with the Long short-term memory (LSTM) structure to solve the basic navigation problem while only the historical interactive data is exploited for updating the parameter vector of the entire network. Simulation results demonstrate that our approach is capable of allowing the UAV to execute coverage-aware path planning tasks in large-scale urban environments. Furthermore, the learning efficiency is greatly improved compared to existing DRL-based approaches.
Target Threat Assessment in Air Combat with BP Neural Network for UAV
Authors: Sheng Lei , Li Lun , Wu Hanbao , Wang Peng
Published: July 2023

Target threat assessment is the most important element in command control communication and computer intelligence surveillance reconnaissance (C4ISR) system which is the key function in air combat situation analysis and can select the most valuable target to the commander. A threat assessment model of multi-UAV platform cooperative engagement built based on back propagate neural network (BPNN) is present in this paper, which provides a machine learning method for the threat assessment. The BPNN target threat assessment model has six input nodes, 10 hide nodes and 1 output node, which can fit the complicated nonlinear relationship between threat value and target behavior state. Simulation experiment is executed to verify the accuracy of the proposed BPNN target threat assessment method, and the result shows that the method is effective and can be applied to the real air combat.
Compliance verification method on CCAR 25.1443(c) for civil aircraft passenger oxygen system based on blood oxygen saturation
Authors: Cai Kun
Published: July 2023

This paper generally introduces the compliance verification method on airworthiness regulation CCAR 25.1443(c) of popular passenger oxygen system on civil aircraft firstly, then technical interpretation on regulation CCAR 25.1443(c)  is demonstrated and method of satisfying this regulation in Top-Down design is analyzed. For those passenger oxygen system based on blood oxygen saturation which is not directly fulfill the requirement of the regulation, equivalent altitude theory is established to transform mean tracheal oxygen partial pressure required by the regulation to blood oxygen saturation index of equivalent altitude, and user’s blood oxygen saturation of these passenger oxygen system is equivalent or higher than that transformed from the regulation through actual human body physiological test and theoretical analysis from aviation physiology, then compliance to the airworthiness regulation is demonstrated by Equivalent Level of Safety. This paper gives the compliance verification method on the airworthiness regulation for those passenger oxygen system based on blood oxygen saturation on civil aircraft and this method have been used and gotten approval of the Authority for a type of civil aircraft. This paper also provides theoretical basis and test basis for further airworthiness regulation revising of the regulation CCAR25.1443(c).
Study on Simulation Method to Determine the Inflation Threshold of Head Protective Airbag for High-speed Helicopter Pilot
Authors: Feng Zhijie , Fan Chengcheng , Ke Chuanyi , Zhang Haibo , Liu Tao
Published: July 2023

Compared with ordinary helicopters, the flying speed of high-speed helicopters is increased from 350km / h to 450km / h, and the crash speed is bound to exceed 12.8m / s, which greatly increases the probability of collision injury of the pilots’ head. The equipment, such as the traditional safety belts and crashworthy seats, cannot play an effective role in protection. In order to effectively improve the crashworthy survival rate of high-speed helicopter pilots, the main method in European and American countries is to design additional head protective airbags. The paper carried out the study on the simulation method for determining the high-speed helicopter head protection airbag inflation threshold value. Based on LS-DYNA, it has established the impact simulation model of the high-speed helicopter cockpit – seat – safety belt – pilot system. At the same time, the HIC value of the dummy head (no more than 1000N) and the pull force of the shoulder strap (no more than 8890N) are taken as the objective function to simulate the collision process of the man/seat system in multiple states of the high-speed helicopter. Finally, the inflation threshold of the head protective airbag is determined, which provides a critical support for the development of the head protective airbag.
Optimization Design and Experimental Study of Space High-precision Gripper
Authors: Duan Jiaqi , Deng Songbo , Zhi Jiankang , Yang Tao , Shi Yan , Zhao Hongchao
Published: July 2023

To meet the requirements of large tolerance, high precision, soft capture and high reliability of space gripper, a three finger end effector is developed. The gripper adopts a three fingered gripper configuration, which needs to be used together with the corresponding capture adapter. It is characterized by stable grip, high precision, large clamping force, large tolerance and strong correction ability. A 6-DOF microgravity equivalent device is innovatively designed, which adopts the combination of ball bearing and reverse counterweight. In this paper, a ground capture calibration platform is built to fully test the capture accuracy of the gripper. Considering the disturbance of capture load, carrying platform and other factors to capture, the capture stiffness of the gripper is tested and the capture stiffness curve is obtained. Both tests have verified the feasibility and effectiveness of the design.
Design and research of integrated components for microsatellite thermal control system
Authors: Tian Jiyun , Hao Kaiyuan , Feng Zhen , Deng Jinzhi , Zhang Jiangyuan , Zhao Liman , Feng Bo , Nie Shuai , Zhang Xiangbing , Leng Hongfei , Sha Sha
Published: July 2023

With the increasing development of aerospace technology, micro satellites have attracted high attention in the aerospace field due to their advantages such as short development cycle, low system investment, and flexible launch methods. Their high level of internal equipment integration, high heat flux density, complex and uncertain working modes pose new challenges to thermal control design. At present, the thermal control design of micro satellites still mainly adopts passive methods, while active thermal control design has been widely used in the fluid circuit of large spacecraft, mostly in the “task oriented design mode”. Its high design cost, long cycle, poor adaptability and other characteristics cannot be applied to low cost, short cycle, and flexible launch methods of micro satellites. In response to the new problems brought by the high power density and low thermal inertia of microsatellites in thermal control design, this paper proposes an active thermal control fluid loop system suitable for microsatellites. In addition to the cold plate and radiator at the equipment end, other equipment forms an integrated component in the form of a shared substrate. The integrated component has the characteristics of miniaturization, lightweight, and rapid replacement of board and card. Through simulation and technical analysis of key components, We believe that this scheme is reasonable and feasible, providing a new design scheme for the thermal control design of subsequent micro satellites.
Composite power supply topology design with energy-controlled distribution switches
Authors: Tian Liyuan , Liu Jingwei , Sun Guangda , Hou Shuyuan
Published: July 2023

An electric car’s battery is equivalent to a fuel vehicle’s engine, without a battery, it is equal to an empty shell. The single energy supply of the battery is difficult to meet the long-term endurance requirements of electric vehicles. Combined with the existing traditional composite power structure, the advantages and disadvantages of the existing traditional composite power supply structure are analyzed. A composite power supply structure combining a supercapacitor and power battery is proposed. The supercapacitor is responsible for the peak high power output, and the power battery is responsible for smooth power output. Simulation results show that the new composite power supply has noticeable improvements compared to traditional structures regarding energy loss and power distribution.
Research on verticality adjustment scheme of launch vehicle
Authors: Zhao Zhijie , Zeng Yuqin , Xiang Changzheng , Hu Zezhong , Liu Zhendong
Published: July 2023

This paper introduces the current situation of verticality adjustment of launch vehicles at home and abroad, and analyses the problems and risks existing in verticality adjustment of launch vehicles at home and abroad. A new scheme for vertical adjustment of a launch vehicle is proposed in this paper. The paper compares the new and the old schemes with the actual application of a certain type of launch vehicle. The new scheme cancels the level measuring instrument on the rocket, simplifies the operation of rocket verticality adjustment at the launching site, reduces the design requirements for the launching station system, avoids the risk of structural damage and tower interference caused by the data distortion of the horizontal measuring instrument and the verticality adjustment operation of the rocket body.
Study on CO emission during DOC assisted DPF regeneration
Authors: Zhang Deman , Zhang Lujing , Zhao Juntao , Li Bin , Deng Peng
Published: July 2023

Diesel particulate filters is the most effective post-treatment device used to reduce diesel exhaust particulate emissions. As the amount of particulate matter captured in the diesel particulate filter continues to increase, the exhaust pressure of the diesel engine gradually increases, thereby affecting the power performance of the diesel engine. Therefore, when the particulate matter capture amount reaches a certain value, the diesel particulate matter filter needs to be regenerated. Regeneration of diesel particulate filters will produce secondary pollution, of which CO is one of the most important secondary pollution. In this paper, the CO generation mechanism and influencing factors in the regeneration process of diesel particulate filters are analyzed. The effects of exhaust pressure and exhaust flow on CO emission during regeneration are measured through experiments. The results show that when the exhaust back pressure is greater than 80kPa, the CO solubility in the exhaust gas increases rapidly, and decreases linearly with the increase of exhaust flow during regeneration. Therefore, in order to reduce the solubility of CO in tail gas during regeneration of diesel particulate filters, the exhaust back pressure shall be less than 80kPa and the exhaust flow shall be as high as possible.
Study on the effect of combustion efficiency of variable thrust rocket engines
Authors: Wei Yanghong , Li Xiuqian , Che Xueke
Published: July 2023

In this paper, using methane/oxygen as the engine propellant, the single nozzle structure and the coaxial shear injection unit were used to analyse the influence of propellant flow change on the combustion chamber flow field and the influence of different factors on combustion efficiency. The results show that as the pressure of the combustion chamber increases, the concentration of the components increases, the combustion reaction speed is accelerated, and the maximum temperature of the combustion chamber increases, but the radial length of the high temperature area decreases; The pressure of the combustion chamber is proportional to the flow rate of the propellant, the flow of the propellant is reduced, the pressure of the combustion chamber is reduced as a whole, and the transportation speed of the material components in the combustion chamber is increased, which in turn reduces the maximum temperature of the combustion chamber, and ultimately leads to a decrease in combustion efficiency; In the process of continuous change of propellant flow, fuel flow, combustion chamber pressure, combustion chamber temperature and combustion chamber material composition jointly affect the combustion efficiency, but the influence of fuel flow on combustion efficiency dominates.
A fuzzy control method with the optimized intelligent weight function for directional control during aircraft autoland rollout
Authors: Zhang Zhen
Published: July 2023

Aircraft landing rollout process is a complex and high non-linearity process. The mutual effects of tire dynamics, aerodynamics and multi-body dynamics should be taken into considerations. It is difficult to be accurately expressed in mathematics. Aiming at obtaining a good directional control capability during aircraft autoland rollout, a comprehensive simulation system was constructed including all those three aspects above, and a fuzzy control method with intelligent weight function was adopted which is appropriate for systems difficult to be modeled exactly. In the paper’s work, the intelligent weight function was optimized by the power function for the first time. By adjusting the exponential k, the fuzzy control rules can be conveniently and reasonably optimized. Through a set of simulations without crosswind, the optimal k was obtained. Finally, the simulation tests under conditions of 20 kn crosswind with ±5° original drift angles were conducted with the system configured by the optimal k. Accroding to the results, the optimized fuzzy controller can give a good directional control performance.
Civil aircraft brake energy scenario selection and analysis method
Authors: Sun Yuchen
Published: July 2023

This paper expounds the method of determining the civil aircraft brake energy scenario. Brake energy is an extremely important requirement for the carbon disc and fusible plug design of the civil aircraft brake system. In order to determine the brake kinetic energy capacity, following conditions should be considered: designed landing-stop condition, normal landing stop condition, reject takeoff condition and the most severe landing stop condition. As the most severe condition is related to the operational environment, emergency events, the aircraft architecture and system failure conditions, the essay illustrates the principles of how to select the correct scenario, the factors to be considered and the potential most severe condition. With the brake kinetic energy calculation method and the data of a certain type of aircraft, the paper finds out 2 conditions could be the most severe ones for brake energy calculation.