bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Computer Interface (HCI) using EEG signals.
Authors: Siow Eric Ker Siang , Chew Wei Jen , Mun Hou Kit
Published: July 2023

Human Computer Interface (HCI) is a field which studies about the applied information-processing psychology that occurs when humans interact with computers. A Brain Computer Interface (BCI) is one method to achieve this, and a cursor-controlled application is proposed in this paper. This prototype allows users to control the cursor by converting real-time synaptic commands. An electroencephalogram (EEG) data collection exercise was conducted and the experimental subjects were trained to learn how to control the EMOTIV Insight. Each of them had to decide their mental commands and calibrate the headset before the experiment started. Two different training methods, namely normal training and special training, were applied to the experimental group and control group respectively, and the progress of learning and using the cursor-controlled application were recorded in questionnaires. The control group used the normal training method, which has been widely used in other studies while the experimental group used the special training method, which allows them to decide the content and strategy of mental commands. The objective of this project is to have all the subjects from both experimental groups control 2 commands with an accuracy above 80% after 4 hours of training and observe which group gets better results. It was a randomized controlled trial (RCT) and double-blind trial, and one of the subjects turned his strategy from control group to experimental group during the experiment without informing the experimenter in advanced. In the outcome, the highest accuracy obtained by the 3 subjects in the experimental group are 50%, 81.25% and 100% respectively, and the highest accuracy obtained by the subject in the control group is 62.5%. In short, the accuracy of the experimental group is averagely higher compared to the control group, and 66.6% of the experimental group managed to control 2 commands with an accuracy above 80%.
Coagulation-flocculation process for greywater treatment using Chitosan and Hibiscus Sabdariffa
Authors: Chen Tsr , Ismail N , Oh KS , Tee LH
Published: July 2023

Greywater means faecal free wastewater from households and buildings. Recycled greywater can be used for daily activities where freshwater is not necessary. Coagulation and flocculation technique in water recycling mostly utilize chemical coagulant alum. However, alum residue in water causes neural diseases and the process produces toxic sludge. Hence, natural coagulant is a safer alternate. Previous studies had proved the efficiency of different types of natural coagulant used individually and as a combination. However, the combination of chitosan and H. Sabdariffa had not been tested. The objective of this research is to investigate the efficiency of chitosan and H. Sabdariffa used alone and combined in greywater treatment. Jar test experiment was conducted using 0.5 L greywater in beakers mixed with the coagulants. The pH and coagulant dosage in each beaker were manipulated to determine the optimum condition. The greywater was then mixed rapidly for 4 minutes at 140 rpm, then slowly for 20 minutes at 30 rpm. Before assessing the final turbidity and Chemical Oxygen Demand (COD), the beakers were allowed to settle for an hour. At pH 4, 0.8 mg/L of chitosan reduced turbidity by 51 % and COD by 60 %. With a dosage of 200 mg/L, H. Sabdariffa demonstrated its best effectiveness at pH 2, resulting in an 88 % reduction in turbidity and a 53 % reduction in COD. When chitosan and H. Sabdariffa were combined, the optimal composition was determined to be 40% chitosan and 60% H. Sabdariffa by weight at pH 4, resulting in a turbidity reduction of 94% and a COD reduction of 56%. The same experiment was carried out using alum at pH 6 and a coagulant dose of 200 mg/l, turbidity and COD were reduced by 96% and 62% respectively. respectively. As a result, the performance of chitosan and H. Sabdariffa have been shown to be comparable to alum in the treatment of greywater, separately and in combination.
Response surface methodology optimization for the enhanced antioxidant activity of Eucalyptus deglupta leaves extract
Authors: Chin K X , Chua B L
Published: July 2023

Eucalyptus deglupta, from the Myrtaceae family, is known to possess strong antioxidant activities. Ultrasound-assisted extraction was used in this research, and it aimed to maximize the antioxidant activity of Eucalyptus deglupta leaves extract. The Response Surface Methodology (RSM) optimization was performed coupled with central composite design with four extraction parameters, namely extraction temperature, extraction time, solvent-to-feed ratio, and ultrasound power at 30 to 60°C, 30 to 70 min, 10 to 30mL/g, and 270 to 330 W, respectively. The maximized antioxidant activity was 57.80%, with optimized extraction conditions of extraction temperature at 31.70°C, extraction time of 70 min, solvent-to-feed ratio of 13.33 mL/g, and ultrasound power of 330 W. Statistical analysis from ANOVA showed that the quadratic model of antioxidant activity was of good fit with coefficient of determination, R
2 of 0.7958. The RSM model of antioxidant activity was validated with the optimized extraction conditions and a relative error of 3.79% was obtained.
The study of thermal & mechanical properties of EPDM compounded with TiO2
Authors: Sin K X , Ahmad H , Yap Hoon , Ismail Hafizul Azizi
Published: July 2023

This study attempts to investigate the usage of titanium dioxide as a viable nanofiller for fabrication of ethylene propylene diene monomer (EPDM) nanocomposites used as thermal insulators. For this study, three different filler loadings (1, 3, 5 % wt.) of titanium dioxide nanofiller are incorporated into the polymer matrix to form the nanocomposites. The thermal and mechanical characteristics of the resulting nanocomposites were compared to EPDM which has not been compounded with TiO2 nanofiller (neat). The thermal characteristics of the polymers were tested using thermogravimetric analysis. Mechanical parameters of the polymers were evaluated via tensile testing with dog-bone specimens according to ASTM D638 standards. Thermal performance of TiO2-impregnated EPDM nanocomposites showed definite improvements, with 1% wt. nanofiller loading having 1 °C improvement over neat EPDM at 5% weight loss and 1 °C improvement at 50% weight loss respectively. Tensile testing showed lower elongation at break (EB) and higher tensile strength (TS) characteristics for nanocomposites with 1% wt. & 3% wt. nanofiller loading compared to neat EPDM. At 5% wt. nanofiller loading, higher EB and lower TS readings were recorded for the nanocomposite, likely resulting from uneven nanoparticle distribution during sample fabrication due to nanofiller particle agglomeration.
Monofacial and Bifacial Photovoltaics Systems with Uniaxial Solar Tracking
Authors: Bhayat Mohamed Humaid , Vaithilingam Chockalingam Aravind , Oruganti Kameswara Satya Prakash , Sivasubramanian Ramsundar , Ardhanari Jagadeeshwaran
Published: July 2023

The technology behind Bifacial Photovoltaic systems has existed for a long time but only recently gained popularity due to the increased surface area for the absorption of solar radiation by the rear-side of the bifacial Photovoltaic (PV) panel. The bifacial gain and output energy yield (kWh) is affected negatively by self-shading leading to non-uniformity in the absorbed irradiance. The purpose of this research is to simulate and investigate the effect of varying parameters including the elevation of a bifacial PV module from 0.5 m to 1.0 m with a step size of 0.1 m and its effect on the absorbed irradiance and subsequent output energy yield (kWh). Uniaxial solar tracking combined with varying the elevation is implemented by positioning the bifacial PV system in an East-West orientation with an azimuth angle of +90° (facing East); this follows the sun’s hourly elevation angle and path throughout the day. Three albedo of values 0.2 which represents grass, 0.6 which represents fresh white concrete and an ideal albedo of 0.99 is combined with the variation in elevation of the bifacial PV module and is further analysed and compared with a monofacial PV module. Simulation results from TracePro show that East-West tracking reduces the Incident angle closer to 0° which results in higher Flux (W) collected by the surface, except for time intervals at 8:00:00 AM and 18:00:00 PM where the sun is located furthest away from the model. The energy yield (kWh) of the bifacial PV panel first increases sharply from an elevation of 0.5 m to 0.8 m where a peak value of 4748.8 kWh is observed, followed by a drop in energy yield (kWh) at 0.9 m and saturation at 1.0 m; hence the elevation parameter of 0.8 m is determined to be the point of inflection. The BGE at 1 m has a significant value of 0.302 which translates to 30.2% in bifacial gain. The largest difference in energy yield (kWh) is observed to be 1114.55 kWh (30.67% increase) at 0.8 m; the bifacial PV module greatly outperforms the monofacial PV module at this elevation in the uniaxial solar tracking system and is determined to be the optimal value.
Modelling and Experimental Investigation on the Differential Protection of Transmission Line
Authors: Alsakati Ahmad Adel , Raja Venkatesh Krishna , Vaithilingam Chockalingam Aravind , Prakash Kameswara Satya , Gamboa Reynato Andal
Published: July 2023

Due to the significant impact of the fault on power systems and the failure of protection devices, power system operators and researchers have given reliability a great deal of consideration. The modern IEC 61850 standard is used recently to improve communication systems in digital substations and allow signals to be shared between the devices. Differential protection is used to protect the transmission lines, cables, and transformers, as it detects the faults by comparison of the currents flowing into and out of the protected devices. In this research, MATLAB/Simulink has been utilized to simulate the differential protection by using two current transformers (CTs) and to analyze the current waveforms of CTs. A model of the transmission line has been implemented in Taylor’s University Lab to validate the simulation results and measure the differential current, which equals the current summation of two CTs. The outcomes of the research show that the phase shift in the secondary side of CTs between two terminal points is zero and the value of differential current is zero under normal operating situations. However, the differential current has increased in each of the following cases: one CT is connected to the system with the wrong polarity or under an internal fault.
Energy and Economic Sustainable Illumination Design for a Gymnasium: A Case Study
Authors: Rosdi Mohd Farhan Mat , Sathyamohan Jayson , Maniyarasu Yugeisvar , Kuok Nicholas Tiong Foo
Published: July 2023

Gymnasium lighting design is crucial to provide better visibility, improve overall mood and serve a good experience to the occupant. Conventional artificial lighting might serve these well, but it consumes a significant amount of energy. In this report, a sustainable lighting design for a gymnasium at Taylor’s University, Subang Jaya, Malaysia, is developed per the SIRIM 33:2019. The aims are to provide better energy-efficient and sustainable lighting design solutions while maintaining good visibility, overall mood, and meeting the required illumination level. The design is developed in a 3D lighting simulation software, the DIALux Evo 10. The proposed LED lighting design is compared with the existing high-pressure sodium high-bay lighting system. Criterion such as the illuminance level, glare rating index, colour rendering, energy performance and economic assessment are analysed. Result of the analysis shows that the proposed LED luminaires achieved of 68% potential energy consumption reduction, a payback period of 4.9 years and an annual life cost cycle of RM 1, 345.76, compared to the existing fluorescent luminaires’ annual life cost cycle of RM 3,570.29. This shows that LED luminaires have better energy performance, and improved cost saving while producing better illuminance level output. The outcome of this study can be considered for future gymnasium lighting design to achieve energy and economic sustainability.
Classification and Detection of Obstacles for Rover Navigation
Authors: Lim Joshua H X , Phang Swee King
Published: July 2023

In this research project, the author aims to achieve Level 3 conditional automation whereby the researched Unmanned Ground Vehicle (UGV) is bound to classify and detect its own obstacle with human assistance as it cruises through a plantation field. Recognizing the different classes of obstacles enable the UGV to plan out the most efficient path to meet its desired goal. The purpose of this research project was to develop a classification and detection of obstacle and an optimal path planning algorithm suitable to be implemented for relieving the working process in an extreme condition plantation field. This paper presents an algorithm whereby it can conduct image-based obstacle detection through image masking and model prediction, along with a trigonometrical-based path planning approach. The proposed algorithm should hypothetically allow the UGV to conduct real-time path planning as it classifies some common obstacles such as leaves, rocks, and branches existing in a plantation field. As the waypoints were marked from the Ground Control Station (GCS), the UGV will travel towards the given waypoints to complete the given mission. When the UGV meets an obstacle, it will first differentiate whether it’s traversable, followed by running the proposed algorithm to avoid the risk of destructing the UGV by choosing a collision free path. The basic idea is to apply path planning by considering the available spacing between the detected obstacle by comparing with a predefined threshold. Through the provided threshold value, the UGV can identify the type of obstacle yet to be detected. For instance, obstacles within the given range of value can be labelled to be a leafy obstacle, otherwise it is not considered to be a leafy obstacle. To ensure the behaviour and safety measure of the UGV to run smoothly, the author had undergone model training for an elevated model prediction by training and deploying a custom training loop through TensorFlow. Nevertheless, MATLAB was utilized to test out the concept of the path planning algorithm to examine its behaviour as untraversable obstacles were met. All these implementations can further grow in the agricultural industries as it can aid humans with performing tedious and impossible tasks on site.
Numerical Investigation of Hybrid Savonius-Darrieus Vertical Axis Wind Turbine at Low Wind Speeds
Authors: Eftekhari Hesam , Al-Obaidi Abdulkareem Sh Mahdi , Srirangam Sucharita
Published: July 2023

The need for electricity on the Earth is increasing day by day, and this requires building more electric power plants where most of the power plants cause CO2 emission which would increase the global warming. Using wind energy as one type of renewable energies, would contribute to reduce the global warming. In countries such as Malaysia where the average annual wind speed is 2-2.5 m/s using wind energy is a challenge because of the low wind speed. However, using a hybrid Savonius-Darrieus vertical axis wind turbine in low wind speed areas, the performance of the wind turbine may increase, and the starting rotation speed will decrease. This research aims at a comprehensive study on a hybrid Savonius-Darrieus wind turbine with helical Savonius rotor combined with helical and straight bladed Darrieus rotor. In this research, a base model with the name of Model Base was generated and two models with new configurations were generated in SOLIDWORKS. A numerical studies and simulation were conducted on these three designs using Ansys Fluent to identify the more suitable combination for low wind speed areas. Based on the obtained result hybrid Savonius-Darrieus with helical Savonius rotor and helical Darrieus rotor were found to be the most suitable combination because of their stable aerodynamic performance throughout a full rotation. Best performance for these models was found to be at 0.45 TRS with maximum torque and power coefficients of 0.68 and 0.306 respectively.
Review and aerodynamic analysis of NACA 2415 morphing wing for variable span and scale morphing concepts using CFD analysis
Authors: Kabir A , Al-Obaidi A S M , Myan F W Y
Published: July 2023

Morphing wings made a significant advancement in aircraft engineering by improving aerodynamic performance for better fuel efficiency and are still under research. This paper reviewed and investigated some morphing wing types including the variable sweep, trailing edge, leading edge, variable span, variable chord, or scale, and airfoil morphing among others. Based on the review, two types of morphing wings were chosen for detailed investigation, and they were variable span and variable scale. Each morphing concept from the selected morphing wing types was implemented in airfoil wing configuration for aerodynamic performance analysis. Computational Fluid Dynamics (CFD) simulation is used to design and analyse morphing wing configurations of the chosen morphing concepts. In this research, two CFD analyses were investigated based on wing configuration; each consists of chosen morphing concept. Before the main CFD simulation of morphing wing analysis, CFD analysis of reference data of a typical NACA 2415 airfoil was verified. The lift coefficient of the morphing wing obtained from CFD analysis was compared with the unmorphed NACA airfoil wing to evaluate the morphing wing’s aerodynamic performance. It is concluded that there is an improvement in lift coefficients using the morphing concept cases, showing improved aerodynamic performance.
A preliminary study of chemical property and thermal stability of potassium chloride encapsulated in starch-alginate matrix
Authors: Chen Ying Si , Phang Siew Wei , Shuib Anis Suhaila
Published: July 2023

A potassium controlled-release fertilizer was fabricated in a starch-alginate matrix by using calcium chloride as a cross-linker. 16 formulas were designed with varying amounts of alginate and potassium chloride with the same amount of starch and calcium chloride, and most of the formulas can form beads successfully. High sodium alginate and low potassium chloride assembled better shape and higher encapsulation efficiency. The highest encapsulation efficiency ratio of starch, sodium alginate, and potassium chloride was 5:1:10 in the 16 formulas. The bonding of alginate and starch, and calcium chloride were evidenced by FTIR, and the study of TGA revealed good thermal stability and compatibility between the polymers and potassium chloride.
Integrated smart public parking system for Malaysia
Authors: Qi Low Zhi , Tien Douglas Tong Kum , King Phang Swee
Published: July 2023

Searching for unoccupied parking spots is a challenge in most modern cities. The increase in the number of vehicles, limited parking spaces and low-speed parking search exacerbated traffic congestion. Consequently, smart parking system solutions have grown in popularity. Smart parking systems were developed in the early 2000s and have advanced to help with parking issues in various countries. In Malaysia however, there is slow adoption of smart parking systems although the need is equally urgent. The aim of this study is to investigate the feasibility of applying a parking spot detection system using cameras installed on lampposts for outdoor public parking in Malaysia. This study aims to demonstrate that a system of lesser complexity can be useful. The proposed solution combined parking spot detection with timing of the parking duration to help drivers monitor their parking time. This can be achieved using image detection and applying filters to identify the occupancy of parking spots. Real-time occupancy data is then exported with an excel file and this data is saved for further study and application development.
Impact of camber angle on the tire tread behaviour in different road conditions
Authors: Djap S , Ku P X
Published: July 2023

The camber angle is one of the wheel alignment properties that is crucial as a slight change to the orientation of the camber angle determines the lifespan of a tire. The stress distribution on the innermost of a tire increase as the positive camber angle is increased, and vice versa, which causes the abnormal uneven premature wear of the tire. This research is done with the main objectives to simulate the performance of tires concerning the camber angle by using the finite element analysis method, and to study the influence of camber angle on different tire tread patterns under two different road conditions, i.e., smooth road and irregular road. Three tire models with different tire tread patterns and two different road conditions are developed using SolidWorks while the investigation of each tire performance is done through ANSYS under static condition in this research. Tire inflation analysis is performed using static structural analysis feature available in ANSYS where the total deformation and equivalent stress are determined based on the specific vertical load applied onto the tire, ignoring any damping effects and inertia. Boundary conditions and other relevant constraints are applied, and then mesh independent test is carried out to all tire models prior to performing the simulation. Based on the simulation results, the maximum total deformation increases as the camber angle increases in both road conditions, while the maximum equivalent stress does not show any trend. It is concluded that tire tread pattern influences the maximum equivalent stress experienced by the tire.
Mechanical Performance of 5-speed Manual Transmission Gearshift Bracket
Authors: Wong J Y , Abu Bakar N Z , Meera Hussain H
Published: July 2023

The main purposes of a gear shift bracket for manual transmission are to hold the gear shift cables and acts as pivot during the gear shifting process. During the gear shifting process, the bracket experiences push and pull reciprocating forces which applied by the driver while selecting or shifting gears. This study presents the development of a simulation model to analyze the mechanical performance of a specific manual transmission gearshift bracket. Based on the simulation results, an optimized bracket design was proposed. Commercial CAD software and Finite Element (FE) Method software were used to perform the simulation. Boundary and initial conditions were applied to the FE model which was based on the real-life mechanical movement of the bracket during gear shifting process. The boundary and initial conditions included fixed position, displacement and both select and shifting loads by following actual test requirements which replicated the movement of the actual model during gear shifting process. Specific mechanical ratio formula was used to obtain the magnitude of loads that was experienced by the gear shift bracket in both select and shifting gears action. The simulation of the gearshift bracket provided outcome parameters such as total deformation, maximum stress and safety factor value. Based on the safety factor value, the model was eligible for topology optimization process and it was modified to gain the optimized model. Then, the same simulation setup was used for the optimized model. The modified design bracket was able to provide a 7% reduction in mass, a 25.15% increase in maximum deformation, a 46,78% increase in maximum stress and, a 36.74% decrease in safety factor value by comparing it to the original model. Although the modified model has lower strength, but its safety factor value is still within the minimum requirements. This concludes that the simulation model allows the manufacturer to undertake design iteration and analyze its performance without producing any physical prototypes and conduct any actual test, thus saving development cost and time.
Study on the performance characteristics and failure analysis of exhaust valves
Authors: Yong M F , Ku P X
Published: July 2023

Exhaust valves are a type of valve that can commonly be found in the top section of the cylinder block in an engine. When failures occur on the exhaust valve, the engine has a high possibility to result engine failure or breakdown. This will affect the user where the user requires to spend a huge amount on repairing costs or engine replacement. Thus, this research aims to investigate the effect of the exhaust valve’s material on its performance and identify the appropriate material which could increase its fatigue life in a four-stroke internal combustion diesel engine. A three-dimension (3D) Computer-aided design model of the exhaust valve was generated by using SOLIDWORKS and undergo static structural analysis as well as thermal analysis. The measure variables are von-mises stress, total deformation, temperature, total heat flux and directional heat flux by using ANSYS Finite Element Analysis. Stainless steel 304 alloy and Aluminium-Silicon Carbide (Al-Sic) materials are the manipulated variable that was applied to the 3D CAD model exhaust valve to undergo all the analyses. Before performing all the analyses, the appropriate mesh method and mesh sizing was identified by referring to the mesh metrics spectrum and performing a mesh independence test. The results from the analysis were collected and tabulated for comparison and discussion purposes. From the analysis, the maximal thermal stress was determined in the valve stem region. By appointing Stainless Steel 304 alloy on the exhaust valve, the durability and the fatigue life are improved as the material can achieve a smaller value of temperature distribution, total heat flux, total deformation, and higher von-mises stress. This research provided a better understanding of the effect of an exhaust valve material on its performance characteristic.
Singularity resolving in solution of the boundary integral equation in two-dimensional vortex methods
Authors: Izmailova Yulia , Marchevsky Ilia , Sokol Kseniia
Published: July 2023

The problem of 2D incompressible flow simulation around airfoils with sharp edges and corner point is considered. The solution of the boundary integral equation with respect to vortex sheet intensity arising in Lagrangian vortex method has weak singularity that cannot be resolved correctly in the framework of the existing Galerkin-type numerical schemes. It is shown that for piecewise-smooth bounded solutions the known schemes allow for solution reconstruction with high quality and provide the 2-nd order of accuracy, while for singular solution their order of accuracy goes down to the 1-st. A numerical scheme is suggested that allows for solution singularity resolving and provides the 2-nd order of accuracy. As a model problem, the added mass tensor components computation is considered, since its exact value is known for the Joukowsky wing airfoil with sharp edge (cusp point).
Hybrid Barnes – Hut/Multipole algorithm application to vortex particles velocities calculation and integral equation solution
Authors: Kolganova Alexandra , Marchevsky Ilia , Ryatina Evgeniya
Published: July 2023

The approximate fast algorithm is developed that makes it possible to calculate velocities of the vortex particles in two-dimensional flow simulations by using vortex methods. It is adapted to efficient solution of the boundary integral equation arising at each time step of simulation. The proposed method can be considered as generalization of the classical Barnes – Hut method, taking into account some ideas of the Fast Multipole Method. Some model problems are considered that can be solved by using vortex methods, the developed fast algorithm is implemented for multi-cores CPUs and (with some modifications) for GPUs. The scalability of the code is rather high; the developed algorithms can run with millions of vortex particles taking only tens or hundreds of milliseconds per time step; linear systems with dimension of about 104 can be solved on multicore CPU in tens milliseconds.
Readout electronics for the CEPC vertex detector prototype and beam telescope
Authors: Yan Z. , Hu J. , Wu T. , Zhou J. , Li S. , Zhang X. , Huang X. , Hu Y. , Wang W. , Liang Z. , Wei W. , Zhang Y. , Wei X. , Zhang L. , Qi M. , Zeng H. , Jia X. , Zhou X. , Guimarães da Costa J. , Fu J. , Zhang H. , Li G. , Wu L. , Dong M. , Li X. , Casanova R. , Zhang L. , Dong J. , Wang J. , Zheng R. , Lu W. , Grinstein S.
Published: July 2023

The proposed Circular Electron Positron Collider (CEPC)
imposes unique requirements on the vertex detector. In response, the
MOST1 and MOST2 projects were launched with the aim of developing a
fully functional pixel sensor and implementing the prototype of the
inner tracking detector. To efficiently manage the data flow from
multiple sensors, specialized readout electronics are required. In
order to evaluate the MOST2 project indicators set for the vertex
detector prototype, a beam telescope was constructed using six
TaichuPix-3 sensor chips and applied in different experiments. The
experimental results demonstrate that the telescope functions
effectively and that the detector prototype meets the design
objectives of the MOST2 project. This project encompasses the design
of the readout electronics, the functionality of the readout system,
the architecture of the telescope, and the specifics of the
telescope experiments.
Highly dynamic X-ray image enhancement based on generative adversarial network
Authors: Yan Hongxu , Liu Yi , Ding Xiaxu , Zhang Haowen , Bai Qiang , Zhang Pengcheng , Gui Zhiguo
Published: July 2023

When using X-ray to detect industrial workpieces, the images
obtained frequently have low contrast, making it difficult to detect
defects. This paper proposes a GAN-based X-ray image enhancement
network to address this issue. In detail, the X-ray image is
concatenated with its antiphase image (as an exposure mask) as the
input image, and a trainable Sobel operator is used to extract the
edge features of the input image. The input image and edge features
are then concatenated and fed into the U-Net generator to be
enhanced. The spatial and channel attention models are used to
adjust feature weights in U-Net, and a detail extraction network is
designed to extract detail features from the input X-ray
image. Furthermore, the extracted detail features are fused with the
image by the generator after contrast stretching to produce the
final enhanced image. Finally, a global-local discriminator is used
to discriminate the authenticity of the image so that the contrast
of the final obtained image is improved and the details are
highlighted. Following experimental validation, the method proposed
in this paper has a significant enhancement effect on industrial
X-ray images and performs well in terms of enhancing image contrast
and highlighting image details.
Biomimetic models of fish gill rakers as lateral displacement arrays for particle separation
Authors: Witkop Erin M , Van Wassenbergh Sam , Heideman Paul D , Sanderson S Laurie
Published: July 2023

Ram suspension-feeding fish, such as herring, use gill rakers to separate small food particles from large water volumes while swimming forward with an open mouth. The fish gill raker function was tested using 3D-printed conical models and computational fluid dynamics simulations over a range of slot aspect ratios. Our hypothesis predicting the exit of particles based on mass flow rates, dividing streamlines (i.e. stagnation streamlines) at the slots between gill rakers, and particle size was supported by the results of experiments with physical models in a recirculating flume. Particle movement in suspension-feeding fish gill raker models was consistent with the physical principles of lateral displacement arrays (‘bump arrays’) for microfluidic and mesofluidic separation of particles by size. Although the particles were smaller than the slots between the rakers, the particles skipped over the vortical region that was generated downstream from each raker. The particles ‘bumped’ on anterior raker surfaces during posterior transport. Experiments in a recirculating flume demonstrate that the shortest distance between the dividing streamline and the raker surface preceding the slot predicts the maximum radius of a particle that will exit the model by passing through the slot. This theoretical maximum radius is analogous to the critical separation radius identified with reference to the stagnation streamlines in microfluidic and mesofluidic devices that use deterministic lateral displacement and sieve-based lateral displacement. These conclusions provide new perspectives and metrics for analyzing cross-flow and cross-step filtration in fish with applications to filtration engineering.
The effect of eliminating sintering during the synthesis of 3D scaffolds using the gel-casting method on their biological characteristics: in vivo and in vitro evaluations
Authors: Seyedmajidi Seyedali , Pourbagher Roghayeh , Seyedmajidi Maryam
Published: July 2023

The possibility of making shapeable three-dimensional scaffolds along with suitable mechanical properties is one of the most challenging points in tissue engineering. This study investigated the effect of the eliminating sintering during the synthesis of Hydroxyapatite/Agarose nanocomposite foam produced by gel-casting method, as bone tissue cellular scaffold, on its biological characteristics. The Hydroxyapatite/Agarose nanocomposite foam was synthesized by gel-casting, and samples were divided into two groups: group S, in which half of the samples were sintered, and group C, which the other half of the samples were left unsintered. To assess in vitro cytotoxicity, the supernatant culture medium was extracted from 100 mg ml−1 foam suspension in complete culture medium after 72 h incubation and diluted into various concentrations. SaOs-II cells were incubated with extracts of each scaffold at different concentrations and analyzed using the MTT assay. Additionally, in vivo characteristics were evaluated by implanting the scaffolds in rat tibia. Overall, the number of living cells was higher in group S than in group C, except for concentrations of 25% and 75% after 24 and 48 h of incubation, respectively. MTT assay results indicated that concentrations below 50% for group S and 25% for group C could be considered non-toxic. All in vivo variables exhibited significant changes over time, with most changes occurring faster in group S than in group C. There was a statistically significant difference between the two groups in terms of inflammation rate, osteocyte, osteoblast, and osteoclast count, as well as remaining biomaterial percentage only on day 30. Despite the delay in the tissue regeneration process observed by eliminating sintering during the gel-casting method, it is recommended as a means of producing reversible polymeric scaffolds with proper handling, cutting, and shaping capabilities that can be easily applied by clinicians during surgery according to the specific defect site.
Effect of immune responses on breath methane dynamics
Authors: Polag Daniela , Keppler Frank
Published: July 2023

Methane (CH4) which can be detected in human breath has long been exclusively associated with anaerobic microbial activity (methanogenesis) in the gastrointestinal tract. However, recent studies challenge this understanding by revealing that CH4 might also be produced endogenously in cells through oxidative–reductive stress reactions. Consequently, variations in breath CH4 levels compared to an individual’s baseline level might indicate enhanced oxidative stress levels, and, therefore, monitoring breath CH4 levels might offer great potential for ‘in vivo’ diagnostics such as disease diagnosis, monitoring the efficacy of treatments, or during the application of personalized medicine. To evaluate the effects from immune responses triggered by infections, inflammations, and induced perturbation by vaccination on CH4 dynamics in breath, two subjects were monitored over a period of almost 2 years. Breath CH4 levels were measured by gas chromatography equipped with a flame-ionization detector. Both subjects exhibited significant deviations (positive and negative, respectively) from their normal CH4 breath levels during periods of potential enhanced immune activity. Deviations from the ‘healthy state’ were indicated by the exceeding of individual CH4 ranges. Moreover, for the first time we could clearly prove CH4 degradation induced through vaccination by measuring stable carbon isotopes of CH4 using gas chromatograph–combustion–isotope ratio mass spectrometry. Hence, breath CH4 concentration and isotopic analyses may be used as a biomarker to evaluate specific immune responses and individual immune states.
Prognostic value of global myocardial flow reserve in patients with history of coronary artery bypass grafting
Authors: Al Rifai Mahmoud , Ahmed Ahmed Ibrahim , Saad Jean Michel , Alahdab Fares , Nabi Faisal , Al-Mallah Mouaz H
Published: July 2023

Aims

It is not well understood whether positron emission tomography (PET)-derived myocardial flow reserve (MFR) is prognostic among patients with prior coronary artery bypass grafting (CABG).

Methods and results

Consecutive patients with a clinical indication for PET were enrolled in the Houston Methodist DeBakey Heart and Vascular Center PET registry and followed prospectively for incident outcomes. The primary outcome was a composite of all-cause death, myocardial infarction (MI)/unplanned revascularization, and heart failure admissions. Cox proportional hazards models were used to study the association between MFR (<2 vs. ≥2) and incident events adjusting for clinical and myocardial perfusion imaging variables. The study population consisted of 836 patients with prior CABG; mean (SD) age 68 (10) years, 53% females, 79% Caucasian, 36% non-Hispanic, and 66% with MFR <2. Over a median (interquartile range [IQR]) follow-up time of 12 (4–24) months, there were 122 incident events (46 HF admissions, 28 all-cause deaths, 23 MI, 22 PCI/3 repeat CABG 90 days after imaging). In adjusted analyses, patients with impaired MFR had a higher risk of the primary outcome [hazard ratio (HR) 2.06; 95% CI 1.23–3.44]. Results were significant for admission for heart failure admissions (HR 2.92; 95% CI 1.11–7.67) but not for all-cause death (HR 2.01, 95% CI 0.85–4.79), or MI/UR (HR 1.93, 95% CI 0.92–4.05).

Conclusion

Among patients with a history of CABG, PET-derived global MFR <2 may identify those with a high risk of subsequent cardiovascular events, especially heart failure, independent of cardiovascular risk factors and perfusion data.
Richard Champion and the Rockingham Whigs: The Aristocratic Politics of a Bristolian Quaker Merchant in the Age of the American Revolution
Authors: Skjönsberg Max
Published: July 2023

This article explores the political career and writings of Richard Champion (1743–1791), a Bristolian Quaker and merchant who acted as a local supporter and agent of the Rockingham Whigs. It aims to recover a forgotten aspect of Lewis Namier’s original ambition to understand eighteenth-century politics through the perspective of relatively ordinary people such as merchants and civil servants. However, against old Namierite assumptions, as well as much of the recent historiography on the post-1760 period in British politics which focuses on a dichotomous conflict between ‘radical Whigs’ and ‘new Tories’, this article restores the importance of the Rockingham Whigs. Importantly, it shows that a commercial Dissenter such as Champion could be fully attuned to the aristocratic and party-centred interpretation of British politics associated with the Rockinghamites and Edmund Burke, and thus encourages us to consider the idea of ‘aristocratic government’ in inclusive and eclectic ways. The case-study of Champion demonstrates that a close reading of political correspondence from the period can confirm, as well as destabilise, the Whig history of party.
Association of gestational thyroid function and thyroid peroxidase antibody positivity with postpartum depression: a prospective cohort study and systematic literature review with meta-analysis
Authors: Sileo Federica , Osinga Joris A J , Visser W Edward , Jansen Toyah A , Bramer Wichor M , Derakhshan Arash , Citterio Valeria , Tiemeier Henning , Persani Luca , Korevaar Tim I M
Published: July 2023

Importance

Postpartum depression (PPD) has a major impact on maternal and offspring well-being, with multiple possible risk factors: Studies on the association of thyroid peroxidase antibody (TPOAb) positivity and thyroid function with PPD provide heterogeneous results.

Objective

To study the association of thyroid function and TPOAb positivity with PPD.

Design

We assessed the association of TPOAb and thyroid function with PPD in a population-based prospective cohort study and performed a systematic literature review and meta-analysis.

Methods

We measured thyroid stimulating hormone (TSH), free thyroxine (FT4), and TPOAb between 9- and 17-week gestation. Postpartum depression was assessed with Edinburgh Postpartum Depression Scale at 2-month postpartum and Brief Symptom Inventory at 2-, 6-, and 36-month postpartum. Additionally, we performed a systematic literature review and meta-analysis assessing this association.

Results

In the present study, there was no association of thyroid function with PPD (TSH: odds ratio [OR] 0.83, 95% CI 0.58-1.19, P = .32; FT4: OR 0.99, 95% CI 0.95-1.05, P = .86) or TPOAb positivity with PPD (OR 0.79, 95% CI 0.47-1.33, P = .37). An impaired thyroidal response to human chorionic gonadotropin (hCG), a surrogate marker for TPOAb positivity, was associated with a lower risk of PPD (P for interaction TSH = 0.04; FT4 = 0.06). Our systematic review and meta-analysis included 3 articles that were combined with the present study. There was no statistically significant association of TPOAb positivity with PPD (OR 1.93, 95% CI 0.91-4.10, P = .08), but the results were heterogeneous (I2 = 79%).

Conclusions and relevance

There was no significant association of TPOAb positivity, TSH, or FT4 with PPD. Our systematic review and meta-analysis revealed high heterogeneity of the current literature. Although TPOAb-positive women should be monitored for postpartum thyroiditis, our findings do not support routinely screening for PPD.
Are active school transport and leisure-time physical activity associated with performance and wellbeing at secondary school? A population-based study
Authors: Jussila Juuso J , Pulakka Anna , Halonen Jaana I , Salo Paula , Allaouat Sara , Mikkonen Santtu , Lanki Timo
Published: July 2023

Background

Physically active pupils may be better and more resilient learners. However, it is unclear whether walking or cycling to school yields similar educational and school-related mental health benefits as leisure-time physical activity. We examined the associations of active school transport and leisure-time moderate-to-vigorous physical activity with perceived academic performance, competency in academic skills, school burnout and school enjoyment.

Methods

We included 34 103 Finnish adolescents (mean age 15.4 years; 53% girls) from the 2015 School Health Promotion study cohort. For the analyses, we used logistic regression, adjusting for major sociodemographic, environmental, lifestyle and physical activity covariates.

Results

Active school transport was positively associated with educational outcomes and school enjoyment, but not with school burnout. For example, compared with non-active transport, 10–30 min of daily active school transport was linked to 30% [odds ratio (OR) 1.30, 95% confidence interval (CI) 1.21–1.40] and 17% (OR 1.17, 95% CI 1.08–1.27) higher odds of high perceived academic performance and high reading competency, respectively. Leisure-time physical activity was robustly associated with all outcomes. For example, compared with the inactive, the most physically active adolescents had 86% higher odds of high perceived academic performance (OR 1.86, 95% CI 1.66–2.08), 57% higher odds of high competency in mathematics (OR 1.57, 95% CI 1.39–1.77) and 40% lower odds of school burnout (OR 0.60, 95% CI 0.52–0.69).

Conclusions

Compared with active school transport, leisure-time physical activity was more strongly associated with educational and school-related mental health outcomes. Nevertheless, walking or cycling to school might lead to improvements in classroom performance and school enjoyment.
Macroevolution of sexually selected weapons: weapon evolution in chameleons
Authors: Van Kleeck-Hann Melissa , Wiens John J
Published: July 2023

The evolution of sexually selected traits is a major topic in evolutionary biology. However, large-scale evolutionary patterns in these traits remain understudied, especially those traits used in male–male competition (weapons sensu lato). Here, we analyze weapon evolution in chamaeleonid lizards, both within and between the sexes. Chameleons are an outstanding model system because of their morphological diversity (including 11 weapon types among ~220 species) and a large-scale time-calibrated phylogeny. We analyze these 11 traits among 165 species using phylogenetic methods, addressing many questions for the first time in any group. We find that all 11 weapons have each evolved multiple times and that weapon origins are generally more frequent than their losses. We find that almost all weapons have each persisted for >30 million years (and some for >65 million years). Across chameleon phylogeny, we identify both hotspots for weapon evolution (up to 10 types present per species) and coldspots (all weapons absent, many through loss). These hotspots are significantly associated with larger male body size, but are only weakly related to sexual-size dimorphism. We also find that weapon evolution is strongly correlated between males and females. Overall, these results provide a baseline for understanding large-scale patterns of weapon evolution within clades.
Impact of HCV Testing and Treatment on HCV Transmission Among Men Who Have Sex With Men and Who Inject Drugs in San Francisco: A Modelling Analysis
Authors: Artenie Adelina , Stone Jack , Facente Shelley N , Fraser Hannah , Hecht Jennifer , Rhodes Perry , McFarland Willi , Wilson Erin , Hickman Matthew , Vickerman Peter , Morris Meghan D
Published: July 2023

Background

Men who have sex with men who ever injected drugs (ever MSM-IDU) carry a high hepatitis C virus (HCV) burden. We estimated whether current HCV testing and treatment in San Francisco can achieve the 2030 World Health Organization (WHO) HCV elimination target on HCV incidence among ever MSM-IDU.

Methods

A dynamic HCV/HIV transmission model among MSM was calibrated to San Francisco data, including HCV antibody (15.5%, 2011) and HIV prevalence (32.8%, 2017) among ever MSM-IDU. MSM had high HCV testing (79%–86% ever tested, 2011–2019) and diagnosed MSM had high HCV treatment (65% ever treated, 2018). Following coronavirus disease 2019 (COVID-19)–related lockdowns, HCV testing and treatment decreased by 59%.

Results

Among all MSM, 43% of incident HCV infections in 2022 were IDU-related. Among ever MSM-IDU in 2015, HCV incidence was 1.2/100 person-years (95% credibility interval [CrI], 0.8–1.6). Assuming COVID-19–related declines in HCV testing/treatment persist until 2030, HCV incidence among ever MSM-IDU will decrease by 84.9% (95% CrI, 72.3%–90.8%) over 2015–2030. This decline is largely attributed to HCV testing and treatment (75.8%; 95% CrI, 66.7%–89.5%). Slightly greater decreases in HCV incidence (94%–95%) are projected if COVID-19 disruptions recover by 2025 or 2022.

Conclusions

We estimate that HCV incidence will decline by >80% over 2015–2030 among ever MSM-IDU in San Francisco, achieving the WHO target.