bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Cascading Failure Evolution Process of High Proportion New Energy Power System
Authors: Shen Zhengwei , Sun Huadong , Zhong Wuzhi , Wang Ansi , Zhao Bing , Xu Shiyun
Published: June 2022

The strong randomness of new energy, the weak anti-disturbance ability of power electronic equipment, and the interactive influence of multiple uncertainties in the source, network, and load side make the cascading failure evolution process of the high-proportion new energy power system more complicated. In order to reveal the evolution process of cascading failures, based on the defined key characteristic events, this paper divides the evolution process of cascading failures of high proportion new energy power system into the initial stage, development stage, and deterioration stage, and expounds its cascading situation in stages. Based on a DC project, cases with DC system was constructed, and the evolution process of cascading failures in high-proportion new energy power systems was simulated and analyzed.
Flame morphological characteristics of buoyant jet fires under different upward inclined nozzles
Authors: zhao Jinfei , Liu Jiahao , wang Jian
Published: June 2022

Flame morphological characteristics of buoyant jet fires from different upward inclined conditions have been experimentally studied in current work. The ethylene fueled jet flames were produced through a round nozzle with an inner diameter of 6mm. The results show that that both the flame horizontal projection length Lph
and the vertical flame height L0
increase with the increasing of heat release rate Q. For a given Q, the Lph
decreases with the increasing of upward inclined angle, while the L0
shows an inverse trend. The fitting results demonstrate that both the Lph
and L0
can be well correlated by the dimensionless heat release rate Q*.
Numerical simulation of gas-liquid two-phase flow on an attitude control system
Authors: Zhu Fengqi , Liu Wen , Li Xiaobei , Li Zhenjiang , Yan Tiantian
Published: June 2022

This paper introduced an attitude control system, which used saturated carbon dioxide as a medium. Through energy conversion, the system converted the pressure energy of gas-liquid mixed carbon dioxide into velocity energy and formed supersonic flow through the nozzle to generate thrust and torque. Compared with the compressed gas attitude control system, the carbon dioxide system had a better compelling specific impulse. With the continuous consumption of the medium, a large amount of liquid carbon dioxide was transformed into a gaseous state. Simultaneously, the pressure variation was slight, which was conducive to control. With a higher initial temperature, more liquid carbon dioxide was consumed, and the thrust was more significant under the same conditions of tank volume and carbon dioxide mass; meanwhile, the faster the temperature decreased.
A fault diagnosis method for power grid based on image feature extraction
Authors: Wu Qinge , Wan Guoliang , Song Zhichao , Li Penglei
Published: June 2022

In order to solve the problem that the traditional power grid fault diagnosis along the railway requires a lot of manpower and material resources, this paper proposes a fault diagnosis method on the power grid along the railway based on image feature extraction. A variable function family series method is designed to extract features of faults. For the fault image denoising, a convolution filter method is used, and the number of 2 denoising layers is selected. At the same time, extracting the decomposition coefficient features and energy features of power grid image faults. Moreover, the matching diagnosis method is given. The fault is finally identified based on the similarity. To compare with the existing fault diagnosis methods, the correct diagnosis rate of the fault diagnosis method proposed is more than 92%. From experimental comparison results, this diagnosis effect not only has higher precision, stronger anti-interference ability, but also has faster diagnosis speed.
Design of multi-robot collaborative navigation and control system based on ROS and laser SLAM
Authors: Zheng Zhuoling , Gong HaoYu , Duan RuoBing , Qiu XinYu , Zou Jiajun
Published: June 2022

Through in-depth research in the current robot field, a design scheme of cooperative navigation and control system for multiple robots based on ROS and laser SLAM is proposed. Compared with a single robot, multi-robot cooperation can improve the operation range and efficiency, and is suitable for more diversified scenarios. The system design includes multi-machine mapping, multi-machine global and local path planning, multi-machine navigation, real-time obstacle avoidance, multi-machine dynamic task assignment. Through the centralized control structure, the robot collects the lidar data in real time to build the map in real time and realizes the integration of multi-machine map building. Then, the path planning algorithm is called to plan the path. Combined with the dynamic task allocation algorithm, the efficiency of multi-robot cooperative operation is maximized and the execution experience is provided for the implementation of other similar projects.
Object Detection and Ranging System Based on Binocular Vision
Authors: Guo Haizhou , Li Zili
Published: June 2022

For the Census transform stereo matching algorithm is susceptible to noise leading to mis-matching, a stereo matching algorithm based on the improved Census transform is proposed, which improves the Census transform reference value selection and incorporates the image gradient information to form the initial cost. Train the lightweight network model NanoDet to quickly detect and obtain the object position, and combine the object disparity and camera parameters to obtain the distance of the object, and transplant the system to an embedded device for practicality verification. After analyzing and verifying the experimental data, it shows that the anti-noise capability of the improved algorithm is significantly improved, and the proposed method can quickly complete the detection and ranging tasks on embedded devices with high reliability and practicality.
Research on Robust Detection System of Vehicle Attitude Fusion Features Based on Multi-Sensor Fusion
Authors: Hu Wen , Kang Longyun , Yu Zongguang
Published: June 2022

With the rapid development of artificial intelligence technology, the field technology of intelligent vehicles is becoming more and more mature. In order to solve the problem of difficult to extract the positional information due to the vestigial point cloud of moving vehicles acquired by LiDAR in complex traffic scenes, a real-time positional estimation method for dynamic targets based on point normal vector features of multi-sensing fusion is proposed. The least-squares fitting algorithm is used to solve the point normal vectors on the target surface, the principal component analysis is used to solve the number of cluster centers of the point normal vectors by adaptive clustering algorithm on the high-dimensional data, the clustering point fitting plane is obtained, and the mutually perpendicular planes representing the point normal vectors are selected as the X and Y axes of the coordinate system to which the target to be measured belongs, and the multi-target sensing fusion feature technology is combined with the sensing features of radar laser and vision, and the point cloud position calculation is completed. The experimental results show that the method can estimate the posture parameters of the moving vehicle in real time and exhibit good robustness.
The realization of a broadband light absorber via the synergistic effect of graphene and silicon nanostructures
Authors: Fan Jiakang
Published: June 2022

Due to the increasing demand for clean energy, it becomes more and more necessary to find out more efficient ways to generate clean energy. Because of this, the light conversion efficiency of different materials has been largely studied. The purpose of the study is to investigate how the silicon pyramidal nanostructures and graphene layer affect the light-absorbing performance of materials and achieve a broadband light absorber. Simulations of four experimental groups, including both with nanostructure and graphene, with nanostructure and without graphene, without nanostructure and with graphene, both without nanostructure and graphene, are done to obtain and compare the data through the method of finite difference time domain (FDTD). By analyzing the simulation results, it is found that the silicon pyramidal structures can improve the light absorption within the range of visible light. Moreover, the presence of graphene layers can improve the light absorption within the range of near-infrared to infrared light. The number of layers can also have effects on light absorption.
Laser metal deposition of Ta-10W alloy based on annular laser cladding with internal wire feeding
Authors: Cao Jiazhao , Kong Lingchao , Chen Yongxiong , Zhang Zhibin , Liang Xiubing , Xia Ming , Sun Bo
Published: June 2022

Laser metal deposition is a new type of laser forming technology with the advantages of small heat affected zone, low dilution rate and high bonding strength. Ta-10W is a high temperature refractory material, which often used in aerospace fields. However, the high melting point and thermal conductivity causes Ta-10W to be prone to cracks collapse during processing and forming. Annular laser cladding provides a feasible way to solve the contradiction between high temperature service performance and processing performance of Ta-10W due to its high energy density, freedom of direction and nearly 100% material utilization. In this paper, Ta-10W cladding layers without cracks and pores were successfully deposited on the Nb substrate based on the wire-annular laser cladding technology. The hardness of the cladding layer is 4 times that of the Nb substrate and the dilution rate is extremely low. The Ta-10W wire must be in the center of the annular laser, otherwise the cladding may fail to form. It is found that the larger the wire feeding speed results in the smaller the aspect ratio; while the larger scanning speed, defocus distance and laser power result in the larger aspect ratio. This work opens up a new path for the fabrication of refractory metals, which is significant for processing high temperature materials.
Study on Component Stability and Curing Process of Polyurethane Reinforcement Material
Authors: Song Weiguo , Liu Xiangyuan , Dong Hao
Published: June 2022

Polyurethane (PU) reinforcement material was prepared by polymeric MDI, water glass, polyether polyol, dioctyl phthalate, and the catalyst as the raw materials. The stability of the component A and the curing process of PU reinforcement material were studied by viscosity analysis, compression test, scanning electron microscopy (SEM) and transmission/diffuse reflectance infrared spectroscopy (FTIR/DRIFTS). The results show that the component A of PU reinforcement material has good stability, and the compressive strength of PU reinforcing material prepared by placing components A and B for 28 days is still above 50 MPa. Moreover, during the curing process of PU reinforcement material, the increase of the crosslinking density of the organic phase and the compressive strength of the composites are promoted by the reaction between isocyanate groups and water from the inorganic phase. At the same time, the resulting Na2CO3 in the inorganic phase is transported by water and enriches in the interphase region to form needle-like crystals.
Preparation of ZnO-BiOCl Composite and its Visible-light Photocatalytic Degradation of RhB
Authors: Hong Jin , Gang Siqi , Wang Fei , Lu Guang
Published: June 2022

The ZnO-BiOCl composite were prepared by a soft chemical method. And crystalline phase, morphology, optical property and photocatalytic efficiency of ZnO-BiOCl compound semiconductors were studied by XRD, SEM, DRS and RhB photodegradation under visible-light irradiation. The results showed that ZnO-BiOCl compound semiconductor was significantly more active than ZnO or BiOCl, since ZnO-BiOCl compound semiconductor may facilitate the transfer of charge carriers and retard the e--h+ recombination. Moreover, the photocatalytic degradation of RhB over ZnO-BiOCl composite sample is the highest, which is also caused by the combination of the photocatalytic performance of ZnO and the photosensitization performance of BiOCl.
Simulation analysis of thermal stress/strain of single fiber and multi-fiber composites caused by elevated environment temperature
Authors: LIN Mei , ZHANG Tiejun , FENG Yu , LIU Songjing , ZHOU Zhangwen
Published: June 2022

To study thermal expansion problem caused by environment temperature changes during service life, single and multi-fiber finite element models were established to investigate thermal stress/strain of composite. Single fiber model was shown that longitudinal thermal stress/strain distribution of fiber or matrix is uniform, but stress/strain distribution of transverse direction was more complex than longitudinal direction. Furthermore, longitudinal and transverse thermal stress at composite free end zone is higher than that of in inner zone. Then the influence of different fiber arrangement on thermal stress was discussed by finite element model of multi-fiber composite. It indicated that damage initiation would emerge at somewhere randomly in fiber regular arrangement model. But in fiber random arrangement model, initial damage will concentrate on interface of fiber-rich zone. In addition, thermal expansion model in this paper may provide simple and practical method to calculate thermal stress/strain, so as to prevent matrix cracking or interface debonding due to thermal stress concentration.
Analysis of the vibro-acoustic behaviours of underwater reinforced rectangular plates
Authors: Ye Jiazhi , Sun Yao
Published: June 2022

In this paper, the vibration and sound radiation of underwater stiffened plates with arbitrary boundary condition have been studied. The vibration of the structure is described by an improved Fourier series, the water-load acts on the structure is solved by Rayleigh integral, and the dynamic response is solved by an energy method. The results show that the increase of plate thickness and boundary constraint can enhance the vibration and sound transformation ability of underwater rectangular plate, and the mechanism is that the increase of vibration mode frequency increases the radiation efficiency of the dominant acoustic radiation mode. By analyzing the effect of stiffening mode and quantity on acoustic radiation, it can be seen that for the plate (1,1) mode, the longitudinal stiffening mode has the lowest vibration energy conversion rate, and the main mechanism is that the dominant acoustic radiation mode has the lowest radiation efficiency, while the transverse stiffening mode has the highest radiation efficiency. In addition, when the reinforcement is distributed, the natural frequency and the radiation efficiency of the corresponding dominant acoustic radiation modes of the stiffeners are reduced, the vibration- acoustic conversion of the plate showed a decreasing trend.
DSMC Study of Strong Shear Nonequilibrium Phenomenon in Hypersonic Knudsen-Layer Flows
Authors: Liu Wenbin , Zhang Jinbai , Lee Chun-Hian
Published: June 2022

A series of plane Couette flows of rarefied argon gas under different flowfield settings are simulated by the direct simulation Monte Carlo method. The relaxation process of strong shear nonequilibrium is systematically studied. The results show a qualitatively platform-shaped distribution of molecular streamwise velocity under the conditions of small wall spacing (roughly in the Knudsen layer), and large shear rate and wall speed. The analysis of this phenomenon will help understand the relaxation process of hypersonic Knudsen-layer flow and provide some references for future modelling research.
Structural damage detection based on data fusion method
Authors: Wu Zhe , Xia Wei , Zhang Yuteng
Published: June 2022

In order to improve the accuracy of structural damage detection, data fusion technology is applied to structural damage detection. Three damage identification algorithms based on vibration are used to analyze the damage state. Then, the improved D-S combination method was used to combine the obtained diagnosis results to obtain the final diagnosis results. The results show that this method can effectively improve the accuracy of structural damage detection and has a good application prospect in engineering.
Dynamics simulation of rolling bearing system with pedestal looseness in speed-up train
Authors: Yang Juping , Wang Junguo , Zhao Yongxiang
Published: June 2022

The paper mainly studies the dynamics characteristics of the roller bearing system with pedestal looseness in speed-up train. Considering eccentricity, damping coefficient, stiffness of shaft, and support forces of roller bearing, a centralized mass model of roller bearing system of speed-up train is presented. Moreover, numerical analysis method is adopted to solve the dynamics responses. Based on the trajectory cures, phase plane portraits, Poincaré maps, and amplitude spectrum cures, the dynamics characteristics are analysed when the motor rotating speed and gap of the looseness are changed. The simulation results reveal some complex dynamic behaviour such as periodic motion, quasi-periodic motion, multi-periodic motion and chaotic motion. These results will help us understand and harness these dynamics behaviour of the proposed bearing system of speed-up train.
Finite Element Model Updating Approach for Structural Health Monitoring of Lightweight Structures Using Response Surface Optimization
Authors: Eidukynas D , Adumitroaie A , Griškevičius P , Grigaliunas V , Vaitkūnas T
Published: June 2022

Mechanical defects in the structure changes it’s vibration response. There is a wide variety of methods that examine changes in measured vibration response to detect, locate, and characterize damage in structural and mechanical systems. One method to evaluate the structural changes and to analyse their causes is the Finite Element Model Updating (FEMU). The objective of this research is to investigate the FEMU procedure for mechanical damage identification and to propose an experimental-computational SHM method for lightweight structures. The structural dynamic response to impact excitation of a structure with and without defects are collected from transient and modal analysis using Ansys FE software. Afterwards, FEMU algorithm using Ansys Surface Response Optimization is investigated for its applicability to damage identification. Obtained results revealed the possibility to use this algorithm with having minimum discrepancy between parameters obtained from experiments and finite element modelling.
Evaluation of oxygen consumption at biologically active surfaces using scanning electrochemical microscopy
Authors: Zinovicius A , Rozene J , Dirma G , Striska L , Stankaitis S , Morkvenaite-Vilkonciene I
Published: June 2022

Scanning electrochemical microscopy (SECM) is a local electrochemical analysis technique, which performs scanning of the sample by ultramicroelectrode (UME) [1]. The result of measurement usually is current, which depends on the electrochemical properties of the surface of interest. The errors can be observed if UME geometry is not ideal [2,3]. This happens after UME polishing or breaking after contact with the sample surface. And the aim of this research was to evaluate oxygen consumption at biologically active surfaces using scanning electrochemical microscopy. That is why the oxygen consumption at the surface of interest with UME of different geometry was evaluated in this work. The model results were compared with experimental data. The computational experiment was performed with the SECM model using diffusion equations in the COMSOL program. This model could be further improved to measure diffusion rates with different probe geometries and coefficients.
Small size 2-DOF piezoelectric platform for unlimited locomotion
Authors: Čeponis A , Mažeika D , Jūrėnas V , Vasiljev P , Bareikis R , Borodinas S , Ostaševičius V
Published: June 2022

The paper represents a numerical and experimental investigation of a 2-DOF piezoelectric positioning platform that can provide unlimited locomotion in the plane. The platform's operation principle is based on the excitation of the first bending mode of piezoelectric bimorph plates. A numerical investigation of the 2-DOF platform was performed, and it was found out that the suitable vibration mode of the bimorph plates occurs at 23.54 kHz Harmonic response analysis showed that the maximum displacement amplitude of the contact reached 561.12 μm or 2.67 μm/Vp-p while an excitation signal of 210 Vp-p was applied. The experimental study was performed and showed that maximum linear velocity of 44.45 mm/s or 0.212 mm/s/Vp-p were obtained while the load of 55.68g and applied and electrical signal of 210 Vp-p was used. In addition, at the same conditions output force of the platform was measured, and it was found that the platform is able to provide 44.16 mN of output force.
Mathematical modelling and theoretical research of micropositioning system
Authors: Subačiūtė - Žemaitienė Jurga , Trečiokaitė Vaiva , Šešok Nikolaj , Šutinys Ernestas , Dzedzickis Andrius , Tamošiūnas Justas , Masalskyi Viktor , Bučinskas Vytautas
Published: June 2022

In this paper, modelling and theoretical research of micropositioning system with stepper motor are proposed. The aim of our research is to provide a method, which is suitable for modelling a ball-screw based positioning system controlled by a stepper motor. A created dynamical model of micropositioning system mechanical parts. The second type of Lagrange equation is used to construct the mathematical model. For modelling micropositioning systems, Matlab/SIMULINK software is used. MatLab is used to perform calculations of some equations, and SIMULINK is used to create a dynamic model of a micropositioning system and simulate system operation. Analysis of motion smoothness showed that even for systems with relatively small screw radius and pitch 1/4 microstepping mode are unable to provide smooth movement. The smoother the movement, the less energy is required to overcome friction.
An optimisation problem for exoskeleton-aided functional rehabilitation of an upper extremity
Authors: Falkowski P
Published: June 2022

With pandemics, a problem of non-guaranteed constant access to rehabilitation aroused. As civilisation diseases attack a significant share of the population, providing motor treatment seems to be one of the biggest challenges towards the healthcare system of the future. While taking into account the severe level of disabilities and unexpected circumstances, the trainings may require being held in a house of a patient. Moreover, due to emergencies, a physiotherapist may not be able to participate in it personally. Thus, to mitigate the repercussions of such situations, advanced mechatronic systems for remote-home-rehabilitation have to be developed. Moreover, surveyed physiotherapists, claim that function-oriented training, robot aid, remote treatment and home therapy are the leading trends for rehabilitation of the future. Combining these is relatively difficult, as automated robotic rehabilitation requires an advanced control system. As to partially support motion along the pre-programmed trails, an optimisation problem needs to be solved. Not only to follow the trail transitionally but also to control a tilt of a gripped object and to avoid immediate large changes of velocities and accelerations if not necessary. This paper presents an approach towards an optimisation problem based on an exoskeleton of three driven and two free degrees of freedom. Simulated function-oriented training consists of diverse typical motions, such as drinking, eating, writing, steering a control wheel, lifting a bag from the ground, and lifting an object onto a shelf. Based on these, an optimisation problem is formulated. Works presented in the paper are an integral part of a planned long-term research on a home-remote-rehabilitation with a use of an exoskeleton.
Quality Research of Edge Banding of Unit Furniture
Authors: Miškinytė Ugnė , Juknelevičius Romualdas
Published: June 2022

Edge banding is used to cover cut sides of wood materials such as plywood or particleboard. The quality of two different furniture edge banding materials and their thickness were studied in this paper. The research was focused on most widely used in the Lithuanian furniture industry acrylonitrile butadiene styrene (ABS) and oak veneer. The experiments were performed to investigate the mechanical properties of materials and SolidWorks Simulation were made as well. The conclusions and recommendations can ensure the improvement and optimization of the processes of furniture industry. Structure of the paper: introduction, review of literature, methodology of experiment, results of research and their consideration, conclusions, references.
5DOF planar – rotary motion piezoelectric robot
Authors: Čeponis A , Jūrėnas V , Mažeika D
Published: June 2022

A novel resonant type five degrees of freedom (5DOF) mobile piezoelectric robot is proposed and analysed. The piezoelectric robot performs unlimited linear working motion in the plane and rotates the positioning table or sphere about three axes independently. The piezorobot can be used for precise positioning or transportation of small objects and make complicated locomotion trajectories. The piezoelectric robot is designed as a compound structure and includes a piezoelectric ring and a special ring-shaped bronze layer. Electrodes of the piezoelectric ring are divided into six equal sections. Excitation of the piezoelectric robot is performed by using a single switched harmonic signal applied to the particular electrode. The operation principle of the piezoelectric robot is based on the excitation of the third radial vibration mode of the piezoelectric ring. The numerical and experimental study was performed, and the operating principle was validated. The maximum linear velocity of 18.8 mm/s and rotational speed of 31.3 rpm were achieved when load of 25.1g and excitation voltage of 200 Vp-p were applied.
Manganese oxide nanoparticles inhibit selectively the in vitro and in vivo growth of human colorectal SW620 adenocarcinoma cells
Authors: Razumov Ivan Alekseevich , Troitskii Sergei Yurievich , Solovieva Olga Igorevna , Boldyrev Nikita Dmitrievich , Zavjalov Evgenii Leonidovich
Published: June 2022

A promising area of oncotherapy is the use of nanomaterials for diagnostics and imaging, as well as for delivering drugs and direct effect agents to tumour cells. We used earlier manganese oxide nanoparticles (NP MnO) as magnetic resonance imaging agents for visualisation and suppression of in vitro and in vivo growth of human glioblastoma cells. The present study was to demonstrate the selective antitumor effect of NP MnO against human tumour cells of different tissue origins, in particular, cells SW620, human colorectal adenocarcinoma. It was shown that NP MnO can inhibit selectively in vitro growth of SW620 cells; the index of selective cytotoxicity against human colorectal adenocarcinoma cells was 20. The range of optimal NP MnO doses was determined using subcutaneous introduction of the nanoparticles to SCID mice; the doses no more than 0.96 mgMn kg−1 had practically no local toxic effect in the animals. The subcutaneous administration of NP MnO in the specified dose range inhibited the growth of SW620 xenografts in SCID mice and led to an increase in their life expectancy. With administered NP MnO in doses of 0.32 and 0.96 mgMn kg−1, the index of inhibition of tumour growth for 21 days from the beginning of the introduction of nanoparticles was 43.0% and 69.8%, respectively. NP MnO seem promising for developing nanotheranostics agents for the visualisation and treatment of human tumours of different tissue origins.
Design and fatigue analysis of diagonally reinforced structures with a negative Poisson’s ratio lattice material
Authors: Cai Liuxi , Hou Yanfang , He Yao , Li Yun
Published: June 2022

In this paper, a typical negative Poisson’s ratio lattice structure was studied and several diagonally reinforced 3D lattice structures were designed and analysed using the finite element method. On this basis, the fatigue life of the unreinforced and reinforced structures was calculated using SIMULIA Fe-safe software. Meanwhile, the fatigue failure process of the lattice structure was systematically simulated and quantitatively analysed by combining the multiaxial fatigue damage model. Results show that the enhancement design from the cell structure can provide an anti-diagonal shear enhancement effect. The structure A, B, and C can decrease the maximum von Mises stress by 95.8, 97.1, and 94.66%, and increase the compressibility by 80%, 56%, and 127%, respectively. The structure A enhancement yields the best overall performance in terms of structural stress, compressibility, and negative Poisson’s ratio properties enhancement. Compared with the unreinforced structure, the lifetime distribution of the structure A reinforced structure changes in both position and level. The overall lifetime has been improved from 102.813 of the unreinforced structure to 107 of the reinforced structure. Quantitative calculation of the fatigue damage is consistent with the fatigue life prediction results, which further validate the effectiveness of the diagonal enhancement method and the enhancement structure of the negative Poisson’s ratio lattice structure.
Structure modification of nonsteroidal brassinolide-like compound, NSBR1
Authors: Takimoto Seisuke , Nishikawa Bunta , Matsuo Midori , Hinata Shiori , Hisatomi Taiki , Yamagami Ayumi , Nakano Takeshi , Nakagawa Yoshiaki , Miyagawa Hisashi
Published: June 2022

Brassinolide (BL) is a possible plant growth regulator in agriculture, but the presence of a steroid skeleton hampers the field application of BL in agriculture because of its high synthetic cost. We discovered NSBR1 as the first nonsteroidal BL-like compound using in silico technology. Searching for more potent BL-like compounds, we modified the structure of NSBR1 with respect to 2 benzene rings and the piperazine ring. The activity of synthesized compounds was measured in Arabidopsis hypocotyl elongation. The propyl group of butyryl moiety of NSBR1 was changed to various alkyl groups, such as straight, branched, and cyclic alkyl chains. Another substituent, F, at the ortho position of the B ring toward the piperazine ring was changed to other substituents. A methyl group was introduced to the piperazine ring. Most of the newly synthesized compounds with the 3,4-(OH)2 group at the A ring significantly elongated the hypocotyl of Arabidopsis.
Molecular Analysis With 16S rRNA PCR/Sanger Sequencing and Molecular Antibiogram Performed on DNA Extracted From Valve Improve Diagnosis and Targeted Therapy of Infective Endocarditis: A Prospective Study
Authors: Mularoni Alessandra , Mikulska Malgorzata , Barbera Floriana , Graziano Elena , Medaglia Alice Annalisa , Di Carlo Daniele , Monaco Francesco , Bellavia Diego , Cascio Antonio , Raffa Giuseppe , Sciacca Sergio , Luca Angelo , Pilato Michele , Conaldi Pier Giulio
Published: June 2022

Background

Molecular analysis (MA) on heart valve (HV) improves the microbiologic diagnosis of infectious endocarditis (IE). The main drawback of MA is the lack of antimicrobial susceptibility information.

Methods

We conducted a prospective cohort observational study of consecutive adult patients from April 2012 to May 2021 who underwent valve surgery at our hospital. The performance of MA, blood cultures (BC) and valve cultures (VC), and the diagnostic and therapeutic impact of MA were evaluated. Molecular antibiogram results were compared to culture-based antimicrobial susceptibility testing (AST).

Results

A total of 137 patients with definite IE and 52 patients with no IE were enrolled in the study. Among IE cases BC, VC, and MA were positive in 75 (55%), 30 (22%), and 120 (88%) of IE cases, respectively. Among 62 cases of BC-negative IE (BCNE), 57 achieved diagnosis with MA. MA led to a change of antimicrobial therapy in 92% of BCNE. MA was negative in 100% of patients with no IE. Molecular antibiogram performed on 17 valve specimens that resulted positive for pathogens potential carrier of genes encoding for multidrug resistant mechanisms showed 100% concordance with AST.

Conclusions

MA showed a high specificity and sensitivity in etiological diagnosis of IE. Molecular antibiogram could overcome the major limitation of MA that is the lack of susceptibility testing. We advocate for the inclusion of MA among diagnostic criteria for IE and for a more extensive use of molecular antibiogram when the culture result is negative, and MA is the only positive test.
The Effect of Menopausal Status, Age, and Human Immunodeficiency Virus (HIV) on Non-AIDS Comorbidity Burden Among US Women
Authors: Collins Lauren F , Mehta C Christina , Palella Frank J , Fatade Yetunde , Naggie Susanna , Golub Elizabeth T , Anastos Kathryn , French Audrey L , Kassaye Seble , Taylor Tonya N , Fischl Margaret A , Adimora Adaora A , Kempf Mirjam-Colette , Tien Phyllis C , Sheth Anandi N , Ofotokun Ighovwerha
Published: June 2022

Menopause may impact the earlier onset of aging-related comorbidities among women with versus without human immunodeficiency virus (HIV). We found that menopausal status, age, and HIV were independently associated with higher comorbidity burden, and that HIV impacted burden most in the pre-/perimenopausal phases.
Association of Trends in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Seroprevalence and State-Issued Nonpharmaceutical Interventions: United States, 1 August 2020 to 30 March 2021
Authors: Miller Maureen J , Himschoot Austin , Fitch Natalie , Jawalkar Sucheta , Freeman Dane , Hilton Charity , Berney Kevin , Guy Gery P , Benoit Tina J , Clarke Kristie E N , Busch Michael P , Opsomer Jean D , Stramer Susan L , Hall Aron J , Gundlapalli Adi V , MacNeil Adam , McCord Russell , Sunshine Gregory , Howard-Williams Mara , Dunphy Christopher , Jones Jefferson M
Published: June 2022

Background

We assess if state-issued nonpharmaceutical interventions (NPIs) are associated with reduced rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection as measured through anti-nucleocapsid (anti-N) seroprevalence, a proxy for cumulative prior infection that distinguishes seropositivity from vaccination.

Methods

Monthly anti-N seroprevalence during 1 August 2020 to 30 March 2021 was estimated using a nationwide blood donor serosurvey. Using multivariable logistic regression models, we measured the association of seropositivity and state-issued, county-specific NPIs for mask mandates, gathering bans, and bar closures.

Results

Compared with individuals living in a county with all three NPIs in place, the odds of having anti-N antibodies were 2.2 (95% confidence interval [CI]: 2.0–2.3) times higher for people living in a county that did not have any of the 3 NPIs, 1.6 (95% CI: 1.5–1.7) times higher for people living in a county that only had a mask mandate and gathering ban policy, and 1.4 (95% CI: 1.3–1.5) times higher for people living in a county that had only a mask mandate.

Conclusions

Consistent with studies assessing NPIs relative to COVID-19 incidence and mortality, the presence of NPIs were associated with lower SARS-CoV-2 seroprevalence indicating lower rates of cumulative infections. Multiple NPIs are likely more effective than single NPIs.
Sacubitril/valsartan in an experimental model of heart failure with preserved ejection fraction
Authors: De Angelis A , Cappetta D , Telesca M , Bellocchio G , Urbanek K , Berrino L
Published: June 2022

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Ministry for Education, University and Research

Introduction

The majority of elderly patients with heart failure has a preserved ejection fraction (HFpEF) that constitutes a syndrome characterized by frequent hospitalizations and high mortality. Despite the growing social burden of HFpEF, the comprehension of its pathophysiology is incomplete, and treatment remains largely undefined. Aging itself may contribute independently to deterioration of diastolic function.

Methods

18-month old female Fischer 344 rats were treated with oral administration of either sacubitril/valsartan (60 mg/kg/die, 1:1 ratio) or valsartan alone (30 mg/kg/die) for 12 weeks. Tail-cuff method was used to monitor blood pressure weekly. Echocardiography and left ventricle catheterization were employed to assess systolic and diastolic function, at baseline, and before sacrifice. Cardiac tissue was used for molecular biology and histochemistry assays.

Results

Tail-cuff analysis indicated a comparable decrease in blood pressure between treatments. Hypertrophy also showed a significant reduction with both treatments. On the contrary, myocardial function analysis demonstrated that no treatment was efficacy on diastolic dysfunction. The lack of improvement of cardiac function could be attributed to the inability of the treatments to counteract the accumulation of fibrotic tissue in the left ventricle, which, in turn, is attributable to the failure to reduce the inflammatory process and oxidative stress, and to the inability to modulate angiotensin II pathway.

Conclusion

Our results evidenced that both sacubitril/valsartan or valsartan treatment was able to improve diastolic function and pro-fibrotic remodeling, partly due to a lack of effect on classical and non-classical pathways of angiotensin II.
Nanobodies as novel potential drugs to target cardiac light chain amyloidosis
Authors: Broggini L , Giono M , Speranzini V , Barzago MM , Palladini G , Diomede L , Pappone C , Ricagno S
Published: June 2022

Funding Acknowledgements

Type of funding sources: Private hospital(s). Main funding source(s): IRCCS GRUPPO SAN DONATO

Light chain amyloidosis (AL) is a systemic disease where fibrillar deposition of misfolded immunoglobulin light chains (LCs) severely affects organ functions. Cardiac involvement (75% of all AL cases) results in the worst prognosis for patients (1). Current AL therapies rely on repurposing of chemotherapeutic drugs targeting plasma cells as the source of LCs; however patients with cardiac damage are often too compromised to sustain such regiments. Alternative approaches aimed at destroying AL fibrils are being evaluated in clinical trials. Nevertheless, none of these treatments offer reliable solutions to counteract the life-threatening cardiac involvement in AL (2).

Here, we propose an alternative approach targeting soluble toxic LCs: these immunoglobulin fragments are frequently overexpressed in patients with cardiac damage and have been found to exert toxicity to cardiac cells, making them an ideal candidate as new drug targets for cardiac AL (3). We combined a multidisciplinary approach to scout for and probe next generation AL drugs based on nanobodies designed to specifically bind soluble toxic LCs. Compared to conventional monoclonal antibodies, nanobodies consist of just two heavy chains, with a single variable domain (VHH, ~15kDa) as the antigen-binding region. These nanoscale VHHs can retain full antigen-binding potential upon isolation, establishing them as the smallest, naturally-derived antigen-binding fragment (4).

To reach our aim, 11 different nanobodies against a cardiotoxic light chain (H3), derived from patient suffering from AL (5), were produced and characterized. To identify the most promising among the pool, a detailed characterization of the in vitro binding between H3 and each nanobody was performed, using a series of biophysical techniques, including isothermal titration calorimetry, microscale thermophoresis, bio-layer interferometry, and multi-angle light scattering. Notably, all the nanobodies efficiently bind to H3 forming stable complexes.

Then, to investigate the capability of nanobodies to prevent H3 cardiotoxicity, we used the nematode C. elegans as in vivo model. Indeed, in C. elegans the administration of cardiotropic LCs causes a profound functional and structural damage on the pharynx, considered an "ancestral heart" (6). Interestingly, we found that some of our nanobodies prevented H3 from exerting its toxic activity, as their presences preserve nematode functional parameters. Collectively, our data pinpointed the novel potential role of nanobodies in the development of alternative treatments of AL patients with cardiac involvement.
The Last Voyage of the Gloucester (1682): The Politics of a Royal Shipwreck
Authors: Jowitt Claire
Published: June 2022

The significance of the wreck of the Gloucester on 6 May 1682 en route to Scotland, with James Stuart, duke of York, later James II and VII, on board, is poorly understood. Based on new archival research, this article places the event in its political, cultural and naval contexts in order to re-evaluate its importance to British history and to correct a number of inaccuracies in recent historiography. The wreck occurred at a sensitive political moment when, within the maelstrom of the Exclusion Crisis (1679–81), the Duke was hopeful of securing his place in the succession. However, thanks in part to the cultural vigour of the ‘ship of state’ trope, the disaster risked James being regarded as a pilot and commander unable to steer the nation. Because his political enemies could use the shipwreck as propaganda to undermine his position as heir to the throne, the event in general, and especially the Duke’s behaviour, became popular topics which were debated and contested from Whig and Tory viewpoints. Since the tragedy occurred at sea, one arm of early modern state apparatus that was especially responsive to these debates was the English navy, which was itself in the midst of a power struggle between Crown and admiralty for control over its future direction. The article sheds new light on the far-reaching implications for James’s reign of the sinking of the Gloucester, and argues afresh for the centrality of maritime history to Restoration political history.
The ecological roles of assembling genomes for Bacillales and Clostridiales in coal seams
Authors: Li Yang , Liu Bingjun , Tu Qingyi , Xue Sheng , Liu Xiaozhou , Wu Zhijian , An Shikai , Chen Jian , Wang Zhigen
Published: June 2022

Biogenic coalbed methane is produced by biological processes mediated by synergistic interactions of microbial complexes in coal seams. However, the ecological role of functional bacteria in biogenic coalbed methane remains poorly understood. Here, we studied the metagenome assembled genomes (MAGs) of Bacillales and Clostridiales from coal seams, revealing further expansion of hydrogen and acetogen producers involved in organic matter decomposition. In this study, Bacillales and Clostridiales were dominant orders (91.85 ± 0.94%) in cultured coal seams, and a total of 16 MAGs from six families, including Bacillus, Paenibacillus, Staphylococcus, Anaerosalibacter, Hungatella and Paeniclostridium, were reconstructed. These microbial groups possessed multiple metabolic pathways (glycolysis/gluconeogenesis, pentose phosphate, β-oxidation, TCA cycle, assimilatory sulfate reduction, nitrogen metabolism and encoding hydrogenase) that provided metabolic substrates (acetate and/or H2) for the methanogenic processes. Therein, the hydrogenase-encoding gene and hydrogenase maturation factors were merely found in all the Clostridiales MAGs. β-oxidation was the main metabolic pathway involved in short-chain fatty acid degradation and acetate production, and most of these pathways were detected and exhibited different operon structures in Bacillales MAGs. In addition, assimilatory sulfate reduction and nitrogen metabolism processes were also detected in some MAGs, and these processes were also closely related to acetate production and/or organic matter degradation according to their operon structures and metabolic pathways. In summary, this study enabled a better understanding of the ecological roles of Bacillales and Clostridiales in biogenic methane in coal seams based on a combination of bioinformatic techniques.
Contribution of the Root Component to Soil Respiration in Oriental Beech Stands in Artvin, Turkey
Authors: Akbas Musa , Tufekcioglu Aydın
Published: June 2022

Autotrophic (root) and heterotrophic respiration components respond differently to environmental variables, and each component behaves differently at different time scales, so it is necessary to partition total soil respiration into its components. The aims of this study were determine soil respiration and its root and heterotrophic components in beech stands, examine the relationship between respiration and biogeochemical factors, and assess seasonal variation in soil respiration. Trenching was applied to separate soil respiration components 6 months before measurements. Monthly soil respiration, temperature and moisture measurements, and seasonal soil and root sampling were carried out in Oriental beech (Fagus orientalis L.) stands located in Artvin Saçinka, Turkey from April 2018 to November 2018 and also (except soil sampling) from May 2019 to November 2019. The average contribution of root respiration and heterotrophic respiration to total soil respiration were 58.8% and 41.2%, respectively. Carbon and nitrogen dynamics explained variations of soil respiration with significant models. This study indicates that soil respiration and its components are associated with biogeochemical factors as well as environmental climatic conditions, and each component of respiration responds differently to changes in them.
On a Continuous Sárközy-Type Problem
Authors: Kuca Borys , Orponen Tuomas , Sahlsten Tuomas
Published: June 2022

We prove that there exists a constant $\epsilon> 0$ with the following property: if $K \subset {\mathbb {R}}^2$ is a compact set that contains no pair of the form $\{x, x + (z, z^{2})\}$ for $z \neq 0$, then $\dim _{\textrm {H}} K \leq 2 - \epsilon $.
Green Liquid Chromatography Method for the Determination of Related Substances Present in Olopatadine HCl Nasal Spray Formulation, Robustness by Design Expert
Authors: Kowtharapu Leela Prasad , Katari Naresh Kumar , Sandoval Christian A , Muchakayala Siva Krishna , Rekulapally Vijay Kumar
Published: June 2022

Background

Dual therapeutic nature drug mast cell stabilizer and histamine receptor antagonist olopatadine hydrochloride (OPT) nasal spray does not have an official monograph, and no literature is available. Eye drops formulation had the official monograph for impurities, but the determination was done in two methods.

Objective

A simple and effective green liquid chromatography method to develop and validate for the related substances of OPT nasal spray formulation.

Method

A 25 min gradient method was employed to separate impurities and OPT with a 1.0 mL/min flow rate using a Boston green C8 (150 mm × 4.6 mm, 5 µm) HPLC column. The set wavelength and column oven temperatures were 299 nm and 30°C, respectively. pH 3.5 phosphate buffer–acetonitrile in the ratio of (70:30, v/v) as mobile phase A and (50:50, v/v) ratio as mobile phase B. A Quality by Design (QbD) based Design of Experiments (DoE) was employed to evaluate the robustness characteristics of the analytical method validation.

Results

The obtained RSD from the precision and intermediate precision was 0.4 to 4.1%. The % recovery of the impurities from LOQ to 150% of specification level was 87.5 to 110.3%. The linear regression curves for the impurities with a correlation coefficient of >0.999 indicate that all peak responses are linear with the concentration. The sample and standard solutions were stable for 24 h at benchtop and refrigerator conditions.

Conclusions

All the critical peaks were well separated from the forced degradation studies’ diluent, placebo, and generated degradation peaks. The method validation data and QbD based robustness study results indicate that the developed impurities method fits the routine quality control laboratory use. National Environmental Index (NMEI), Green Analytical Procedure Index (GAPI), Analytical Eco-scale and Analytical Greenness (AGREE) tools expressed the method’s greenness.

Highlights

The proposed method is QbD utilized and green chemistry assessed impurities determination method for OPT in nasal spray formulation.