bluuebunny/crossref_metadata_2025 huggingface dataset:
Discovery of Rift Valley fever virus natural pan-inhibitors by targeting its multiple key proteins through computational approaches
Authors: Fatima Israr , Ahmad Sajjad , Alamri Mubarak A. , Mirza Muhammad Usman , Tahir ul Qamar Muhammad , Rehman Abdur , Shahid Farah , Alatawi Eid A. , Alkhayl Faris F. Aba , Al-Megrin Wafa Abdullah , Almatroudi Ahmad
Published: June 2022

The Rift Valley fever virus (RVFV) is a zoonotic arbovirus and pathogenic to both humans and animals. Currently, no proven effective RVFV drugs or licensed vaccine are available for human or animal use. Hence, there is an urgent need to develop effective treatment options to control this viral infection. RVFV glycoprotein N (GN), glycoprotein C (GC), and nucleocapsid (N) proteins are attractive antiviral drug targets due to their critical roles in RVFV replication. In present study, an integrated docking-based virtual screening of more than 6000 phytochemicals with known antiviral activities against these conserved RVFV proteins was conducted. The top five hit compounds, calyxin C, calyxin D, calyxin J, gericudranins A, and blepharocalyxin C displayed optimal binding against all three target proteins. Moreover, multiple parameters from the molecular dynamics (MD) simulations and MM/GBSA analysis confirmed the stability of protein–ligand complexes and revealed that these compounds may act as potential pan-inhibitors of RVFV replication. Our computational analyses may contribute toward the development of promising effective drugs against RVFV infection.
Liver cancer treatment with integration of laser emission and microwave irradiation with the aid of gold nanoparticles
Authors: Kabiri Saeedeh , Rezaei Fatemeh
Published: June 2022

This paper studies the effectiveness of the integration of microwave field irradiation and laser emission in liver cancer therapy with the aid of gold nanorods, in order to find out the influences of these combinational methods in tumor necrosis. Hepatocellular carcinoma is a kind of liver cancer that usually has a complicated structure, including both of superficial and deep sections. In current research, in deep regions of cancerous tissue, microwave antenna is utilized and in superficial regions, laser beams are irradiated. A Pulsed laser with heating time of 50 s and cooling time of 20 s is utilized for hyperthermia treatment. It should be mentioned that gold nanorods are injected into the tumorous region to enhance the treatment process and reduce the patient’s exposure time. Simulation results showed that at the first step, without any injection of gold nanoparticles, 0.17% of the tumor’s volume encountered necrosis, while at the next stage, after injection of gold nanorods, the necrosis rate increased to 35%, which demonstrates the efficiency of gold nanorods injection on the tumor treatments. Furthermore, the combinational applying of both microwave antenna and laser illumination can eradiate the tumor tissue completely.
Nobiletin resolves left ventricular and renal changes in 2K-1C hypertensive rats
Authors: Iampanichakul Metee , Poasakate Anuson , Potue Prapassorn , Rattanakanokchai Siwayu , Maneesai Putcharawipa , Prachaney Parichat , Settheetham-Ishida Wannapa , Pakdeechote Poungrat
Published: June 2022

This study investigated the effects of nobiletin on cardiorenal changes and the underlying mechanisms involved in two-kidney, one-clip (2K-1C) hypertension. 2K-1C rats were treated with nobiletin (15 or 30 mg/kg/day) or losartan (10 mg/kg/day) for 4 weeks (n = 8/group). Nobiletin (30 mg/kg) reduced high levels of blood pressure and circulating angiotensin II and angiotensin-converting enzyme activity in 2K-1C rats. Left ventricular (LV) dysfunction and remodelling in 2K-1C rats were alleviated in the nobiletin-treated group (P < 0.05). Nobiletin reduced the upregulation of Ang II type I receptor (AT1R)/JAK (Janus kinase)/STAT (signal transducer and activator of transcription) protein expression in cardiac tissue of 2K-1C rats (P < 0.05). The reduction in kidney function, and accumulation of renal fibrosis in 2K-1C rats were alleviated by nobiletin (P < 0.05). Overexpression of AT1R and NADPH oxidase 4 (Nox4) protein in nonclipped kidney tissue was suppressed in the nobiletin-treated group (P < 0.05). The elevations in oxidative stress parameters and the reductions in antioxidant enzymes were attenuated in 2K-1C rats treated with nobiletin (P < 0.05). In summary, nobiletin had renin-angiotensin system inhibitory and antioxidant effects and attenuated LV dysfunction and remodelling via restoration of the AT1R/JAK/STAT pathway. Nobiletin also resolved renal damage that was related to modulation of the AT1R/Nox4 cascade in 2K-1C hypertension.
GDAP1 loss of function inhibits the mitochondrial pyruvate dehydrogenase complex by altering the actin cytoskeleton
Authors: Wolf Christina , Pouya Alireza , Bitar Sara , Pfeiffer Annika , Bueno Diones , Rojas-Charry Liliana , Arndt Sabine , Gomez-Zepeda David , Tenzer Stefan , Bello Federica Dal , Vianello Caterina , Ritz Sandra , Schwirz Jonas , Dobrindt Kristina , Peitz Michael , Hanschmann Eva-Maria , Mencke Pauline , Boussaad Ibrahim , Silies Marion , Brüstle Oliver , Giacomello Marta , Krüger Rejko , Methner Axel
Published: June 2022

Charcot-Marie-Tooth (CMT) disease 4A is an autosomal-recessive polyneuropathy caused by mutations of ganglioside-induced differentiation-associated protein 1 (GDAP1), a putative glutathione transferase, which affects mitochondrial shape and alters cellular Ca2+ homeostasis. Here, we identify the underlying mechanism. We found that patient-derived motoneurons and GDAP1 knockdown SH-SY5Y cells display two phenotypes: more tubular mitochondria and a metabolism characterized by glutamine dependence and fewer cytosolic lipid droplets. GDAP1 interacts with the actin-depolymerizing protein Cofilin-1 and beta-tubulin in a redox-dependent manner, suggesting a role for actin signaling. Consistently, GDAP1 loss causes less F-actin close to mitochondria, which restricts mitochondrial localization of the fission factor dynamin-related protein 1, instigating tubularity. GDAP1 silencing also disrupts mitochondria-ER contact sites. These changes result in lower mitochondrial Ca2+ levels and inhibition of the pyruvate dehydrogenase complex, explaining the metabolic changes upon GDAP1 loss of function. Together, our findings reconcile GDAP1-associated phenotypes and implicate disrupted actin signaling in CMT4A pathophysiology.
The plant rhizosheath–root niche is an edaphic “mini-oasis” in hyperarid deserts with enhanced microbial competition
Authors: Marasco Ramona , Fusi Marco , Ramond Jean-Baptiste , Van Goethem Marc W , Seferji Kholoud , Maggs-Kölling Gillian , Cowan Don A , Daffonchio Daniele
Published: June 2022

Plants have evolved unique morphological and developmental adaptations to cope with the abiotic stresses imposed by (hyper)arid environments. Such adaptations include the formation of rhizosheath–root system in which mutualistic plant–soil microbiome associations are established: the plant provides a nutrient-rich and shielded environment to microorganisms, which in return improve plant-fitness through plant growth promoting services. We hypothesized that the rhizosheath–root systems represent refuge niches and resource islands for the desert edaphic microbial communities. As a corollary, we posited that microorganisms compete intensively to colonize such “oasis” and only those beneficial microorganisms improving host fitness are preferentially selected by plant. Our results show that the belowground rhizosheath–root micro-environment is largely more hospitable than the surrounding gravel plain soil with higher nutrient and humidity contents, and cooler temperatures. By combining metabarcoding and shotgun metagenomics, we demonstrated that edaphic microbial biomass and community stability increased from the non-vegetated soils to the rhizosheath–root system. Concomitantly, non-vegetated soil communities favored autotrophy lifestyle while those associated with the plant niches were mainly heterotrophs and enriched in microbial plant growth promoting capacities. An intense inter-taxon microbial competition is involved in the colonization and homeostasis of the rhizosheath zone, as documented by significant enrichment of antibiotic resistance genes and CRISPR-Cas motifs. Altogether, our results demonstrate that rhizosheath–root systems are “edaphic mini-oases” and microbial diversity hotspots in hyperarid deserts. However, to colonize such refuge niches, the desert soil microorganisms compete intensively and are therefore prepared to outcompete potential rivals.
Probing the molecular structure of aqueous triiodide via X-ray photoelectron spectroscopy and correlated electron phenomena
Authors: Ahsan Md Sabbir , Kochetov Vladislav , Hein Dennis , Bokarev Sergey I. , Wilkinson Iain
Published: June 2022

Liquid-microjet-based X-ray photoelectron spectroscopy was applied to aqueous I3− anions to investigate their valence- and core-level electronic structure, ionization dynamics, associated electron-correlation effects, and nuclear geometric structure.
Catalytic cooperativity between glucose oxidase and gold nanoparticles in the sequential oxidation of glucose to saccharic acid
Authors: Brindle Joseph S. , Nelson Patrick S. , Charde Rashmi P. , Sufyan Sayed Abu , Nigra Michael M.
Published: June 2022

A hybrid glucose oxidase-gold nanoparticle catalyst demonstrates sequential oxidation of glucose to saccharic acid without adding a strong oxidant.
Microfluidics-based rapid measurement of nitrite in human blood plasma
Authors: Gaikwad R. , Thangaraj P. R. , Sen A. K.
Published: June 2022

We report direct and rapid measurement of nitrite in human blood plasma using a fluorescence-based microfluidic method.
A direct mass spectrometry method for cannabinoid quantitation in urine and oral fluid utilizing reactive paper spray ionization
Authors: Borden Scott A. , Saatchi Armin , Palaty Jan , Gill Chris G.
Published: June 2022

Reactive paper spray mass spectrometry mitigates many of the challenges associated with direct cannabinoid measurements, allowing for rapid, reliable and quantitative measurements in oral fluid and in urine at clinically relevant levels.
A direct fixation of CO2 for isotopic labelling of hydantoins using iodine–phosphine charge transfer complexes
Authors: Bow John-Paul J. , Adami Valentina , Marasco Agostino , Grønnevik Gaute , Rivers Dean A. , Alvaro Guiseppe , Riss Patrick J.
Published: June 2022

Herein, we report a method for the isotopic labelling of hydantoins directly from CO2 by means of trimethyl-λ5-phosphine diiodide mediated carbonyl insertion.
Enantioselective Michael addition of aldehydes to maleimides catalysed by surface-adsorbed natural amino acids
Authors: Kozma Viktória , Szőllősi György
Published: June 2022

Chiral hybrid materials obtained by adsorption of primary α-amino acids on the surface of inorganic oxides are economic, recyclable, highly enantioselective heterogeneous catalysts for the Michael addition of aldehydes toN-substituted maleimides.
Development of a series of biobased poly(ethylene 2,5-furandicarboxylate-co-(5,5′-((phenethylazanediyl)bis(methylene))bis(furan-5,2-diyl))dimethylene 2,5-furandicarboxylate) copolymers via a sustainable and mild route: promising “breathing” food packaging materials
Authors: Yi Jing , Li Yuxuan , Zhao Yuhao , Xu Zhanwei , Wu Yuanpeng , Jiang Min , Zhou Guangyuan
Published: June 2022

The monomer PhDM with a particular structure was introduced into PEF to regulate the properties of the copolymer, especially the gas barrier and UV shielding properties, which is promising for food packaging applications.
Scaffold hopping from indoles to indazoles yields dual MCL-1/BCL-2 inhibitors from MCL-1 selective leads
Authors: Drennen Brandon , Goodis Christopher C. , Bowen Nathan , Yu Wenbo , Vickers Gregory , Wilder Paul T. , MacKerell Alexander D. , Fletcher Steven
Published: June 2022

The anti-tumour efficacies of selective inhibitors of anti-apoptotic BCL-2 family proteins are often compromised by the concomitant upregulation of sister proteins. Herein, we describe our efforts to develop dual MCL-1/BCL-2 inhibitors.
Length-dependent symmetry in narrow chevron-like graphene nanoribbons
Authors: Houtsma R. S. Koen , Enache Mihaela , Havenith Remco W. A. , Stöhr Meike
Published: June 2022

We report the structural and electronic properties of narrow chevron-like graphene nanoribbons with a band gap of 1.5 eV. Molecular heterojunctions are formed during on-surface synthesis via a coupling defect consisting of a 5- and 6-membered ring.
Polyester synthesis based on 3-carene as renewable feedstock
Authors: Kränzlein Moritz , Pongratz Stefanie , Bruckmoser Jonas , Bratić Brigita , Breitsameter Jonas Martin , Rieger Bernhard
Published: June 2022

3-Carene is successfully utilized as renewable feedstock for the synthesis of biobased polyesters via ring-opening polymerization or polycondensation. These polyesters showed amorphous or semi-crystalline morphology, influencing thermal properties.
Dual-Task Effects on Concurrent Speech Production in School-Age Children With and Without Stuttering Disorders
Authors: Eichorn Naomi , Pirutinsky Steven
Published: June 2022

Purpose:

Contemporary motor theories indicate that well-practiced movements are best performed automatically, without conscious attention or monitoring. We applied this perspective to speech production in school-age children and examined how dual-task conditions that engaged sustained attention affected speech fluency, speech rate, and language productivity in children with and without stuttering disorders.

Method:

Participants included 47 children (19 children who stutter, 28 children who do not stutter) from 7 to 12 years of age. Children produced speech in two baseline conditions with no concurrent task and under a dual-task condition requiring sustained attention to on-screen stimuli. Measures of speech fluency, speech rate, and language productivity were obtained for each trial and compared across conditions and groups.

Results:

Dual-task conditions resulted in a reduction in stutter-like disfluencies relative to the initial baseline speaking condition. Effects were similar for both groups of children and could not be attributed to decreases in language productivity or a simple order effect.

Conclusions:

Findings suggest that diverting attention during the process of speech production enhances speech fluency in children, possibly by increasing the automaticity of motor speech sequences. Further research is needed to clarify neurophysiological mechanisms underlying these changes and to evaluate potential clinical applications of such effects.

Supplemental Material:

https://doi.org/10.23641/asha.19945838
A database for aesthetic classification of Chinese traditional music
Authors: Xie Lingyun , Gao Yan
Published: June 2022

Artificial intelligence has been a research highlight in recent years. Therefore, quantitative analysis about human perception has been of great concern, for instance, affective computing based on music or picture materials. As music is one of the main art forms of auditory aesthetics, its quantitative studies related to aesthetic perception show great potential. This study proposed the evaluation method of aesthetic categories for Chinese traditional music. According to this method, a dataset with aesthetic‐emotional multi‐annotation was established. The dataset was composed of 500 clips of Chinese traditional music, and it consisted of five aesthetic categories. The distribution characteristics of different aesthetic categories in the emotional dimension space were analysed. Furthermore, by extracting corresponding acoustical features, we tested the accuracy of different classifiers for aesthetic classification. The results showed that the highest accuracy was 65.37% by logistic regression. This work provided a data foundation for the quantitative research and aesthetics computation of Chinese traditional music. The database also can be used for the research of cross‐cultural music perception.
Age‐optimal design for UAV‐assisted grant‐free non‐orthogonal massive access: Mean‐field game approach
Authors: Zhang Hongliang
Published: June 2022

Due to the capability of providing flexible network coverage, unmanned aerial vehicles (UAVs) are a promising solution to support the Internet‐of‐Things (IoT) applications, especially for the area without terrestrial network coverage. In this paper, a UAV‐assisted IoT network is considered, where a UAV serves as an aerial base station to serve ground IoT devices. To support the massive access, grant‐free non‐orthogonal communications are also adopted, where packets generated by IoT devices can skip the handshake process and share a channel with other packets for transmission. With the aim to maintain the information freshness, the age of information (AoI) for the network is first derived, and an AoI minimization problem is formulated as a Stackelberg game where the UAV is the leader and ground IoT devices are followers. However, solving such a problem is challenging as the number of involved followers is large. To simplify the problem, a mean‐field game based approach is proposed, where the average behaviours of followers are considered instead of individual strategies. Simulation results show that the computational complexity of the proposed scheme is almost unchanged with the number of IoT devices while the performance is close to the optimal one.
Design and experimental analysis of high electromagnetic force density moving magnet linear actuator with end ferromagnetic poles
Authors: Akbar Siddique , Khan Faisal , Ahmad Zahoor , Ullah Wasiq , Ullah Basharat , Hussain Shahid
Published: June 2022

A Linear Oscillating Actuator (LOA) generates bi‐directional electromagnetic (EM) force between two extreme points. A new topology of moving magnet LOA with axial magnetised PMs and a C‐shaped stator core is proposed. On each side of the mover, two chamfered tubular‐shaped core material parts are attached. All the design parameters, such as mover mass and EM force of the LOA, are optimised using parametric analysis via parametric sweep, and the optimum values of the parameters are chosen based on design and performance parameters. The LOA's performance is examined for various input loading values and at different oscillation region positions. For various values of time‐dependent supply, the EM force's oscillating nature is analysed. The effect of resonance analysis on input current, stroke to current ratio, and efficiency are discussed. The proposed LOA is compared to current LOA topologies in terms of design structure and performance parameters. The FEM results are validated using a special experimental setup. The proposed LOA produces feasible results for the compressor in a refrigeration system.
Analyzing the multi‐scale characteristic for online car‐hailing traffic volume with quantum walk
Authors: Hu Xu , Niu Xiaoyu , Qian Lingxin , Pan Binghuang , Yu Zhaoyuan
Published: June 2022

The multi‐scale characteristic of online car‐hailing traffic volume can reflect the implied distribution pattern, which is crucial for traffic management and even urban planning. Nevertheless, the spatio‐temporal heterogeneity of online car‐hailing traffic volume makes it challenging to analyze its multi‐scale characteristics effectively. Here, a method named multi‐scale characteristic analysis for online car‐hailing traffic volume with quantum walk (MCATV‐QW) is proposed. MCATV‐QW adopts quantum walks to generate multi‐scale probability patterns that online car‐hailing appears at different locations over time. Then stepwise regression is applied to screen the generated multi‐scale probability patterns, to further analyze the multi‐scale characteristic. We validate MCATV‐QW with online car‐hailing traffic volume in the northeast of Chengdu, China. MCATV‐QW not only achieves better simulation performance, but also reveals the distribution pattern that the influence degree of multi‐scale probability patterns weakens from southwest to northeast of study area. MCATV‐QW also reflects the traffic spatial pattern that is dominated by gradual traffic (48%), with both abrupt (26%) and uniform traffic (26%).
Deep learning‐based hybrid model for the behaviour prediction of surrounding vehicles over long‐time periods
Authors: Gao Xiang , Chen Long , Tai Kangsheng , Cai Yingfeng , Wang Hai , Li Yicheng
Published: June 2022

Autonomous vehicles need to have the ability to predict the future behaviour of surrounding vehicles, which helps with proper trajectory planning and tracking. Many behaviour prediction methods have limited application because they have a very limited prediction horizon. This paper proposes a deep learning‐based hybrid model for behaviour prediction over long‐time periods, including manoeuvre recognition and a behaviour prediction module. In manoeuvre recognition module, the CNN extracts the social characteristics of the target vehicle and LSTM outputs the manoeuvre probability vector to form a contextual feature vector with the social features. In the behaviour prediction module, LSTM and Attention are based on the contextual feature vector to capture multi‐time step information in the behaviour time window to complete the prediction of the target vehicle behaviour. Real‐car collection and open‐source vehicle trajectory datasets were used for training and testing. The results show that the proposed algorithm could predict vehicle behaviour with an accuracy of 89.73% and an average prediction time of 2.032 s, which has a high engineering application value.
Range profile similarity‐oriented method for radar imaging of moving target under low signal‐to‐noise ratio environment
Authors: Xu Xinbo , Su Fulin , Jin Xinfei , Gao Jianjun
Published: June 2022

Inverse synthetic aperture radar (ISAR) imaging is an advanced technique for reconstructing high‐resolution images of moving targets. However, noise interference degrades the readability of the ISAR images under low echo signal‐to‐noise ratio (SNR) environments. Furthermore, noise impairs the performance of ISAR motion compensation, which induces severe defocussing. Thus, a novel range profile similarity‐oriented (RAP‐SO) method with a two‐step denoising strategy is presented. First, attributed to the coherence between ISAR range profiles, the coherent weighted template (CWT) is proposed to preliminarily remove the noise in a high‐resolution range profile (HRRP) and restore the range profile similarity impaired by noise. In order to robustly complete range alignment under a low SNR environment, Keystone transform (KT) is utilised. Thereafter, the weighted template is constructed by virtue of coherent integration. The CWT adaptively gives different weights to HRRP signals and noise, which is called coarse denoising. Second, inspired by the similarities of range profiles, the minimum weighted nuclear norm (Min‐WNN) optimisation is proposed to further reduce the residual noise. The coarse denoised HRRPs are rearranged into an approximate low‐rank matrix. Subsequently, rank‐constraint optimisation on the HRRP matrix via minimising the weighted nuclear norm is performed, aiming to efficiently suppress the residual noise. This step is called fine denoising. As a result, ISAR image quality is significantly improved. Comprehensive experiments illustrate the effectiveness and superiority of the presented method.
Fabrication and characterization of ITO/ZnO/anthraquinone solid dye-sensitized solar cells
Authors: Nkhaili L. , El Kissani A. , Liang C.-T. , Naceur Abouloula C. , Hnawi S. K. , Ait Ali M. , Narjis A. , Outzourhit A.
Published: June 2022

The use of natural dyes as sensitizers in organic solar cells is getting more interest due to its green nature, nontoxicity, low cost and ecofriendly materials. In this paper, two anthraquinone/zinc oxide-based dye-sensitized solar cells (DSSCs) were prepared by a simple and low cost method. The anthraquinone was extracted from Aloe-vera plant and was deposited as a thin film to study its structural and optical properties. ZnO nanoparticles and nanorods were prepared by the RF sputtering and electrodeposition methods, respectively. The Glass/ITO/ZnO/anthraquinone/Al structure exhibited a promising photovoltaic activity.
Characterization of earplugs based on porous polyurethane (PU) and polyvinyl-chloride (PVC) polymers for human ear protection
Authors: Barbara Penpen Komgue Lucrece , Assif Safaa , Faiz Adil , Ennawaoui Chouaib , Ducourneau Joël , Hajjaji Abdelowahed
Published: June 2022

Personal ear protection (PEP) is a device designed to reduce the effects of ambient noise on humans, thus limiting the risk of hearing damage. This damage mainly affects the entire auditory chain (from the tympanic membrane to the cochlea). The aim of this work is to carry out a study of the mechanical properties of the PEP studied to model it subsequently using the finite elements method (FEM). To this end, the aim of this paper will be the study of the morphological and mechanical performance of porous polymers to protect the human ear from vibrations. The influence of air content (Porosity rate, pore size and shape) on the elastic matrix and mechanical properties of porous polymers (Young's modulus and Poisson's ratio) produced from available commercial Polyurethane (PU) and Polyvinyl-Chloride (PVC) were examined and discussed. The authors present a mathematical model that is able to predict the Young’s modulus of porous polymers as a function of matrix characteristics, mechanical excitation and porosity percentage. Porosimeter, Scanning  Electron Microscope (SEM) and Light Microscope (LM) techniques are used for morphological characterizations. PU and PVC earplugs are effective for sound reduction, so they can be used for other applications.
Designing bionic surface grid structure with base structure method
Authors: DING You , ZHOU Zhou , LIU Hongjun , WANG Kelei
Published: June 2022

To improve the efficiency of the composite material wing structure of a solar-powered UAV, this paper proposed an efficient discrete structural topological optimization method based on the notion of bionic design. The method considers the features of such wing structures as discrete stiffness, high aspect ratio and ultralight. Through multi-step optimization, the grid relationship of the base structure method is established with the GRAND method, so as to obtain the design space of discrete topological optimization. First, linear programming is used to solve optimization problems and thus gives the topological relations of a wing structure. Then, by extracting the information on node dimensions of the discrete topological structure, a bionic geometric model is established with the notion of bionic design. In order to obtain the optimal topological form of the bionic surface grid structure of the wing, the finite element analysis and the structural dimension optimization are carried out with the parameterization method. On the condition that design requirements are satisfied, the optimization reduces the weight of the wing by 34.4%, compared with the traditional design methods. Results show that the structural optimization method proposed in the paper is effective for this special composite material wing structure and can be used for the lightweight design of similar structures.
A method for numerical simulation of mode transition process of compression system of variable cycle engine based on throttle valve model
Authors: WANG Hao , LIANG Xiwen , MA Qinghua , Wang Yangang
Published: June 2022

In order to study the aerodynamic characteristics of the compression system of a variable-cycle engine during its mode transition, a low-order model was established based on the throttle valve theory to describe the throttle characteristics of the mode selection valve at its different opening degrees. The model was applied to the outlet of a double-bypass variable-cycle fan in the form of characteristic boundary. A 3D low-order hybrid computational model was established for the numerical simulation of flow fields in the mode transition process of the compression system. The calculation accuracy and effectiveness of the throttle valve model were verified by comparing its calculation results with those of the 3D valve model. The simulation method was further applied to the prediction and analysis of the fan performance variation during the single and double bypass mode transitions of the variable-cycle fan. The simulation results show that: the throttle coefficient, which represents the throttle intensity, has something to do only with the flow area ratio of the valve but has nothing to do with its angle. Therefore, the throttle valve model is universal for valves with different motion angles; the throttle valve model can accurately predict the variation trend of the aerodynamic characteristics of the fan in all stages of the mode transition process. Compared with the 3D valve model, the prediction error of the pressure ratio of the fan in all stages is less than 1.93%, and the efficiency error is less than 1.05%. In the valve closing process, the second-stage rotor performance changes more dramatically, and the first-stage rotor performance changes with lag.
A new signal fault detection algorithm for vector tracking loop in strong noise environments
Authors: WANG Huibin , CHENG Yongmei , TIAN Zhaoxu
Published: June 2022

In the vector tracking loop(VTL) of the satellite navigation system, the signal faults caused by the abnormal atmospheric disturbances or other interferences may be distorted when outputted by the discriminators, due to the nonlinearities in the discriminators. This makes the large bias faults in strong noise environments hard to detect and then the navigation solution may be contaminated. A new signal fault detection algorithm for VTL in strong noise environments is proposed in this paper to deal with this issue. Firstly, the reason and effects of distortion that occurs on discriminator output are analyzed. Then a new code discriminator is designed for signal fault detection, which owns a wider positive correlation output range about the code tracking error thus improving the detection ability for large abrupt bias faults and drift faults in strong noise environments. Later a third-degree spherical-radial cubature rule is employed to estimate the test statistic and its variance matrix. Finally, comparison trials about abrupt faults and drift faults in different noise environments illustrate that the proposed algorithm maintains reliable detection ability about abrupt faults that are larger than 0.5 chips and can detect drift faults in 25~30 dBHz strong noise environments.
Investigation on the flow mechanism of nacelle airframe interaction for podded blended wing body transport
Authors: GU Wenting , ZHANG Binqian , MA Kun , LI Dong , LYU Pengfei , HAN Jie
Published: June 2022

For the flow interaction between the podded engine and the airframe of blended wing body configuration(BWB), taking the 300 seats class BWB civil transport NPU-BWB-300 designed by Northwestern Polytechnical University as the research object, the influence of the podded engines on the BWB airframe at typical high and low speed conditions were investigated by CFD method, and the airframe-nacelle interference mechanism was revealed. The results indicate that the podded engines mainly affect the high speed performance of BWB, but have little effect on the low speed performance. The flow interaction between the airframe and the nacelle at high speed condition is serious when podded the engines, which leads to strong shock wave and flow separation. The flow mechanism of the above-mentioned interaction is as follows: firstly, the large supersonic region and shock wave on the nacelle external surface interferes with airframe surface flow seriously, which induces shock wave and flow separation; secondly, a convergent-divergent channel is formed between the airframe and the nacelle, resulting in the "throat" effect, which produces shock wave and flow separation.
Reliability analysis of composite sandwich structure for fuselage skin based on surrogate model
Authors: DING Zhendong , LI Hongshuang , GUAN Xiaole
Published: June 2022

Composite structures are characterized by multiple source uncertainties in mechanical properties, geometric dimension, etc., and multiple failure modes, which bring challenges to their design and application. In order to explore the reliability analysis method of composite sandwich structures with multi-source uncertainties and multi-failure modes, a parametric finite element model and an acoustic boundary element model were established for deterministic analysis of a fuselage skin sandwich structure. Considering the randomness of the mechanical properties of composite materials and the laminate thickness, the structural reliability models were established for three typical failure modes of sandwich structures: static strength failure, global buckling and vibration noise. In order to reduce the computational effort, the Kriging surrogate models of failure modes were constructed, and the subset simulation method was used to predict the system failure probability of the sandwich structure of fuselage skin. The proposed computational framework provides support and tool for the fine design of composite sandwich structure.
Error research of attitude measurements on low-cost UAV-borne missile
Authors: LI Peng , ZHANG Jie , XU Hongwei , WANG Xuan , WU Heke
Published: June 2022

The framed gyroscope can significantly reduce the cost of missile. However, the gyroscope error problem restricts the acquisition probability and guidance precision of air-to-ground missile. A gyroscope error compensation method based on Taylor series formula is proposed in this paper. Gyro output error sources are analysed in detail, and the gyro output error model of unmanned aerial vehicle load space missile is established, and the mathematical relationship between missile attitude angle and the gyroscope output is deduced. Through the gyroscope on three-axis turntable hardware-in-the-loop simulation test, the correctness and effectiveness of the gyro error model established is verified. The test results show that the proposed error compensation method can control yaw attitude angle error and oblique attitude angle error of UAV-borne missile within 1° respectively in 20 s, and easy to project implementation.
Tensor coaxial calibration of magnetic sensor array
Authors: LEI Yiqin , SUN Zhaolong , HONG Zehong , LIU Qi , ZHONG Peina
Published: June 2022

In order to effectively solve the influence of the magnetic sensor array error caused by axial inconsistency on the measurement accuracy, an array composed of four fluxgate sensors is built by using the Euler rotation matrix, and the consistency correction is carried out. Firstly, aiming at the non orthogonal, scale factor, zero bias and other error factors of the sensor itself, a 9-PARAMETER correction coefficient matrix is constructed to compensate the non orthogonal magnetic field measurement of the sensor, and the ideal orthogonal three component magnetic field measurement value is obtained. On the above-mentioned basis, the reference sensor in the magnetometry array is selected, and the roll, pitch and azimuth of the sensor to be calibrated are transformed to establish the Euler rotation matrix, and the model for 9-PARAMETER consistency correction is constructed. The reference sensor and the sensor to be calibrated are placed on the magnetic gradiometer for experimental verification. The experimental results show that the root mean square error of magnetic field measurement is within 10 nT after the sensor measurement error compensation correction, and the angle error of each axis measurement is within 0.01åfter the consistency correction (4.22 nT). It shows that the magnetic field measurement values of different measuring points in the sensor array can be well projected on the coordinate axis of the reference sensor after correction, and the magnetic field information of the measuring points can be correctly projected, which has high reliability.
An improved entorpy-based representation for mixed uncertainty about intervals and points data
Authors: REN Bo , YUE Zhufeng , CUI Lijie , WANG Xinhe , ZHANG Feng
Published: June 2022

In engineering design problems, intervals refer to any kind of lack of information. This paper presents an improved entorpy-based methodology for a probabilistic representation of a stochastic quantity for which only sparse point data and/or interval data may be available. The combined entropy function is used to measure the uncertainty in data, which is evaluated from the non-parametric probability density function for sparse point data and the cumulative distribution function for interval data, Wherein the entire non-parametric distribution can be discretized at a finite number of points and the probability density values at these points can be inferred using the principle of maximum-entropy, thus avoiding the assumption of any particular distribution. The proposed improved Entorpy-based methodology is then employed in the attempt of interval uncertainty propagation, with the results compared with previous studies. Examples are provided to demonstrate the effectiveness of present method. The study reveals great potentials of the probabilistic method for the treatment of the uncertainty in presence of the sparse point data and/or interval data.
Methicillin-resistenter Staphylococcus aureus (MRSA) – eine zentrale Hygiene-Herausforderung in der Dermatologie
Authors: Schlatterer Kathrin , Maxeiner Horst-Günter , Zouboulis Christos C. , Daeschlein Georg
Published: June 2022

Der Methicillin-resistente Staphylococcus aureus ist ein im täglichen Alltag insbesondere für den Bereich der Dermatologie relevanter multiresistenter gram-positiver bakterieller Erreger. Chronische Wunden und atopische Dermatitis sowie der Typ II-Diabetes mellitus spielen hier als Risikofaktoren eine wichtige Rolle. Dieser Übersichtsartikel fokussiert sich neben Ausführungen zu Bedeutung und klinischem Vorkommen auf eine zusammenfassende Darstellung der Hygieneaspekte bei der Behandlung von MRSA-besiedelten oder -infizierten Patienten. Ziel einer solchen Behandlung mit etablierten Hygienekonzepten ist es, eine mögliche Verbreitung des multiresistenten Erregers von einem Patienten auf andere Personen zu verhindern. Werden diese Hygiene-Maßnahmen umgesetzt und gleichzeitig bei einer Infektion eine evidenzbasierte, nach dem Antibiotic-Stewardship ausgerichtete antibiotische Therapie initiiert, sind dies zwei wesentliche Bausteine, um auch weiterhin, wie in den letzten Jahren schon in Nord- und Mitteleuropa beobachtet, rückläufige MRSA-Prävalenzen zu erzielen.
Ein Fall von Hydroa vacciniforme
Authors: Troyanova-Slavkova Svetoslava
Published: June 2022

Hydroa vacciniforme ist eine sehr seltene Lichtdermatose, die v.a. im Kindesalter auftritt und durch juckende oder schmerzhafte Erytheme, Papeln, urtikarielle Plaques und Blasen in lichtexponierten Bereichen gekennzeichnet ist. Diese Läsionen entstehen nach Sonneneinstrahlung und heilen mit varioliformen, oft depigmentierten Narben ab 1. Wir berichten über eine Patientin, die seit 6 Jahren an dieser Erkrankung leidet und sich nach inkonsequentem Sonnenschutz mit Verschlechterung des Hauzustandes bei uns vorstellte.
Learning of Intracorporal Knot Tying in Minimally Invasive Surgery by Video or Expert Instruction
Authors: Romero Philipp , Gerhaeuser Annabelle , Carstensen Leonie , Kössler-Ebs Julia , Wennberg Erica , Schmidt Mona W. , Müller-Stich Beat P. , Günther Patrick , Nickel Felix
Published: June 2022

Introduction Minimally invasive surgery skill laboratories are indispensable in training, especially for complex procedural skills such as intracorporal suturing and knot tying (ICKT). However, maintaining a laboratory is expensive, and specially trained teachers are in short supply. During the COVID-19 pandemic, in-person instruction has reduced to almost zero, while model learning via video instruction (VID) has become an integral part of medical education. The aim of this study was to compare the learning effectiveness and efficiency of ICKT by laparoscopically inexperienced medical students through video versus direct expert instruction.

Materials and Methods A secondary analysis of two randomized controlled trials was performed. We drew data from students who were trained in ICKT with expert instruction (EXP, n = 30) and from students who were trained via VID, n = 30). A laparoscopic box trainer including laparoscope was used for ICKT. Objective Structured Assessment of Technical Skills (OSATS), knot quality, and total ICKT time were the parameters for the assessment in this study. Proficiency criteria were also defined for these parameters.

Results Students in the EXP group performed significantly better in OSATS-procedure-specific checklist (PSC) and knot quality compared with students in the VID group, with no difference in task time. Of the students who reached the proficiency criteria for OSATS-PSC and knot quality, those in the EXP group required fewer attempts to do so than those in the VID group. Students in both groups improved significantly in all parameters over the first hour of evaluation.

Conclusion For the laparoscopically inexperienced, training in ICKT through expert instruction presents an advantage compared with video-based self-study in the form of faster understanding of the procedure and the associated consistent implementation of good knot quality. Both teaching methods significantly improved participants' ICKT skills.
Radical Cyclization of Ynamides to Nitrogen Heterocycles
Authors: Evano Gwilherm , Zhang Chunyang , Blanchard Nicolas
Published: June 2022

An efficient radical cyclization of suitably functionalized ynamides to nitrogen-containing heterocycles is reported. Upon reaction with tributyltin hydride in the presence of catalytic amounts of AIBN in toluene at 80 °C, a range of ynamides bearing a N-iodopropyl chain could be smoothly cyclized, in a highly regio- and stereoselective manner, to the corresponding 2-arylidenepyrrolidines in good to excellent yields. The exocyclic double bond was in addition shown to be an excellent anchor for further chemical diversification and the generality of this radical cyclization could be highlighted by its extension to the synthesis of other nitrogen heterocycles including piperidines, azepanes, pyrazolidines and hexahydropyridazines.
The role of pancreatoscopy in the diagnostic work-up of intraductal papillary mucinous neoplasms: a systematic review and meta-analysis
Authors: de Jong David M. , Stassen Pauline M. C. , Groot Koerkamp Bas , Ellrichmann Mark , Karagyozov Petko I. , Anderloni Andrea , Kylänpää Leena , Webster George J. M. , van Driel Lydi M. J. W. , Bruno Marco J. , de Jonge Pieter J. F. ,   on behalf of the European Cholangioscopy study group
Published: June 2022

Background Confirming the diagnosis, invasiveness, and disease extent of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas is challenging. The aim of this study was to summarize the literature on the efficacy and safety of peroral pancreatoscopy (POP) in the diagnosis of IPMN, including the impact of pre- and intraoperative POP on the management of IPMN.

Methods The EMBASE, Medline Ovid, Web of Science, Cochrane CENTRAL, and Google Scholar databases were systematically searched for articles. Eligible articles investigated cohorts of patients who underwent POP for (suspected) IPMN.

Results 25 articles were identified and included in this review; with 22 of these reporting on the diagnostic yield of POP in IPMN and 11 reporting on the effect of pre- or intraoperative POP on clinical decision-making. Cannulation and observation rates, and overall diagnostic accuracy were high across all studies. Frequently reported visual characteristics of IPMN were intraductal fish-egg-like lesions, hypervascularity, and granular mucosa. Overall, the adverse event rate was 12 %, primarily consisting of post-endoscopic retrograde cholangiopancreatography pancreatitis, with a pooled rate of 10 %, mostly of mild severity. Regarding the impact of POP on clinical decision-making, POP findings altered the surgical approach in 13 %–62 % of patients.

Conclusion POP is technically successful in the vast majority of patients with (suspected) IPMN, has a consistently high diagnostic accuracy, but an adverse event rate of 12 %. Data on intraoperative pancreatoscopy are scarce, but small studies suggest its use can alter surgical management. Future studies are needed to better define the role of POP in the diagnostic work-up of IPMN.
Comparison of Cesarean Deliveries in a Multicenter U.S. Cohort Using the 10-Group Classification System
Authors: Pasko Daniel N. , McGee Paula , Grobman William A. , Bailit Jennifer L. , Reddy Uma M. , Wapner Ronald J. , Varner Michael W. , Thorp John M. , Caritis Steve N. , Prasad Mona , Saade George R. , Sorokin Yoram , Rouse Dwight J. , Tolosa Jorge E. ,   for the Eunice Kennedy Shriver National Institute of Child Health Human Development Maternal-Fetal Medicine Units (MFMU) Network
Published: June 2022

Objective We sought to (1) use the Robson 10-Group Classification System (TGCS), which classifies deliveries into 10 mutually exclusive groups, to characterize the groups that are primary contributors to cesarean delivery frequencies, (2) describe inter-hospital variations in cesarean delivery frequencies, and (3) evaluate the contribution of patient characteristics by TGCS group to hospital variation in cesarean delivery frequencies.

Study Design This was a secondary analysis of an observational cohort of 115,502 deliveries from 25 hospitals between 2008 and 2011. The TGCS was applied to the cohort and each hospital. We identified and compared the TGCS groups with the greatest relative contributions to cohort and hospital cesarean delivery frequencies. We assessed variation in hospital cesarean deliveries attributable to patient characteristics within TGCS groups using hierarchical logistic regression.

Results A total of 115,211 patients were classifiable in the TGCS (99.7%). The cohort cesarean delivery frequency was 31.4% (hospital range: 19.1–39.3%). Term singletons in vertex presentation with a prior cesarean delivery (group 5) were the greatest relative contributor to cohort (34.8%) and hospital cesarean delivery frequencies (median: 33.6%; range: 23.8–45.5%). Nulliparous term singletons in vertex (NTSV) presentation (groups 1 [spontaneous labor] and 2 [induced or absent labor]: 28.9%), term singletons in vertex presentation with a prior cesarean delivery (group 5: 34.8%), and preterm singletons in vertex presentation (group 10: 9.8%) contributed to 73.2% of the relative cesarean delivery frequency for the cohort and were correlated with hospital cesarean delivery frequencies (Spearman's rho = 0.96). Differences in patient characteristics accounted for 34.1% of hospital-level cesarean delivery variation in group 2.

Conclusion The TGCS highlights the contribution of NTSV presentation to cesarean delivery frequencies and the impact of patient characteristics on hospital-level variation in cesarean deliveries among nulliparous patients with induced or absent labor.

Key Points