bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling multiscale causal interactions between spiking and field potential signals during behavior
Authors: Wang Chuanmeizhi , Pesaran Bijan , Shanechi Maryam M 
Published: January 2022

Abstract

Objective. Brain recordings exhibit dynamics at multiple spatiotemporal scales, which are measured with spike trains and larger-scale field potential signals. To study neural processes, it is important to identify and model causal interactions not only at a single scale of activity, but also across multiple scales, i.e. between spike trains and field potential signals. Standard causality measures are not directly applicable here because spike trains are binary-valued but field potentials are continuous-valued. It is thus important to develop computational tools to recover multiscale neural causality during behavior, assess their performance on neural datasets, and study whether modeling multiscale causalities can improve the prediction of neural signals beyond what is possible with single-scale causality. Approach. We design a multiscale model-based Granger-like causality method based on directed information and evaluate its success both in realistic biophysical spike-field simulations and in motor cortical datasets from two non-human primates (NHP) performing a motor behavior. To compute multiscale causality, we learn point-process generalized linear models that predict the spike events at a given time based on the history of both spike trains and field potential signals. We also learn linear Gaussian models that predict the field potential signals at a given time based on their own history as well as either the history of binary spike events or that of latent firing rates. Main results. We find that our method reveals the true multiscale causality network structure in biophysical simulations despite the presence of model mismatch. Further, models with the identified multiscale causalities in the NHP neural datasets lead to better prediction of both spike trains and field potential signals compared to just modeling single-scale causalities. Finally, we find that latent firing rates are better predictors of field potential signals compared with the binary spike events in the NHP datasets. Significance. This multiscale causality method can reveal the directed functional interactions across spatiotemporal scales of brain activity to inform basic science investigations and neurotechnologies.
Post-processing techniques using 3D Slicer for T1-weighted MRI analysis of radiochromic gel dosimeters
Authors: Lee Hannah J. , Dolan James , Pencea Stefan , Ibbott Geoffrey S. 
Published: January 2022

Abstract
Radiochromic FXG gel dosimeters were investigated for end-to-end validation of TG-119 plans delivered in the pre-clinical Elekta 1.5 T-7 MV FFF MR-Linac. Due to the noise levels in the T1-weighted MR images, this preliminary study investigated post-processing techniques available in 3D Slicer and their impact on gamma passing rates. Binomial blur and discrete Gaussian image filters were identified as the most impactful on increasing gamma passing rates for T1-weighted MR images; however, any application of image filters should be implemented with caution on the interpretation of the results.
Flexible radiochromic dosimeters development for complex irradiation beams
Authors: Tran Johanna , Agelou Mathieu , Amiot Marie-Noëlle , Boissonnat Guillaume , Dehe-Pittance Chrystèle , Girard Hugues , Lazaro Delphine , Simic Vesna , Tromson Dominique 
Published: January 2022

Abstract
In vivo dosimetry for patient radioprotection is a real challenge concerning new radiotherapy treatments. In this study we aim to develop a dosimeter based on tissue equivalent material, flexible and adaptable to the patient morphology in order to perform in vivo dosimetry for complex irradiation beams. Here, we report the evaluation in standard beams of highly flexible dosimeter composed of a silicone elastomer and containing leucomalachite green as radiochromic dye and give a first estimation of LMG-micelle hydrogel response. All results are compared to a commercially available PRESAGE® dosimeter.
Adaptive radiotherapy dosimetry in a challenging geometry: A model gas-filled tissue expander in a helical TomoTherapy beam
Authors: Kairn T. , Lathouras M. , Sylvander S. R. , Trapp J.V. , Crowe S.B. 
Published: January 2022

Abstract
Helical TomoTherapy treatment and delivery systems (Accuray Inc, Sunnyvale, USA) allow off-line adaptation of radiotherapy treatments, with dose calculations that use MV computed tomography (CT) data acquired at treatment. This study aimed to assess the potential dosimetric effects of a gas-filled temporary tissue expander (TTE) on the accuracy of breast radiotherapy dose calculations from both the TomoTherapy treatment planning system (TPS), which uses kV CT data, and the TomoTherapy adaptive radiotherapy (ART) system, which uses MV CT data. A TomoTherapy treatment plan was created and delivered to a 3D-printed rectilinear model of a breast with implanted gas-filled TTE, including a stainless steel CO2 container, and film measurements of the delivered dose were compared against dose calculations from the TPS and ART systems. The film measurements showed that the TomoTherapy TPS provided comparatively accurate dose calculations in the ~550 cm2 volume of air that modelled the gas filling of the TTE and within the surrounding tissue-equivalent materials, except in regions where the beam was transmitted through the stainless steel CO2 container, possibly due to the volume of stainless steel being over-estimated in the kV CT images that were used to generate the treatment plan. The ART system provided more accurate dose calculations than the TPS in regions affected by the stainless steel container, but also over-estimated the dose in the air within the TTE. These results suggest that the TomoTherapy TPS and ART systems could be used to produce reliable dose calculations of breast treatments in the presence of gas-filled TTEs, if kV CT imaging options are chosen to avoid artefacts and minimise the need for density over-rides and if treatment targets that include only clinically relevant tissues, and exclude all TTE components, are used to evaluate and compare the doses calculated by both systems.
Investigation of target dose conformity using normoxic polymer gel dosimetry techniques: A clinical example of 12th thoracic vertebrae SBRT treatment with VMAT
Authors: Venning A , Mundayadan Chandroth M , Morgan C , Roberts M 
Published: January 2022

Abstract
This paper describes the 3D dosimetry verification of a 24Gy in 3 fractions VMAT SBRT treatment delivery to the 12th thoracic vertebrae (T12). With this fractionation regime, the critical isodose value is 17.5Gy to the outer edge of the spinal cord and must not be exceeded. This is a high-risk treatment that could result in severe injury to the patient unless administered precisely. With the use of 3D normoxic polymer gel dosimetry techniques, using MRI readout, a clinical example is presented which shows that the Mid North Coast Cancer Institute’s paraspinal program is capable of delivering complex distributions with high doses to within very tight tolerances. This also demonstrates the strength of normoxic polymer gel as a 3D dosimeter.
RSC: Gel dosimetry as a tool for clinical implementation of image-guided radiotherapy
Authors: Elter A , Dorsch S , Marot M , Gillmann C , Johnen W , Runz A , Spindeldreier C K , Klüter S , Karger C P , Mann P 
Published: January 2022

Abstract
The implementation of new image-guided radiotherapy (IGRT) treatment techniques requires the development of new quality assurance (QA) methods including geometric and dosimetric validation of the applied dose in 3D. Polymer gels (PG) provide a promising tool to perform such tests. However, to be used in a large variety of clinical applications, the PG must be flexibly applicable. In this work, we present a variety of phantoms used in clinical routine to perform both hardware and workflow tests in IGRT. This includes the validation of isocenter accuracy in magnetic resonance (MR)-guided RT (MRgRT) and end-to-end tests of online adaptive treatment techniques for inter- and intra-fraction motion management in IGRT. The phantoms are equipped with one or more PG containers of different materials including 3D printed containers to allow for 3D dosimetry in arbitrarily shaped structures. The proposed measurement techniques and phantoms provide a flexible application and show a clear benefit of PG for 3D dosimetry in combination with end-to-end tests in many clinical QA applications.
End-to-End Quality Assurance of Stereotactic Radiation Therapy Using an Anthropomorphic Head Phantom
Authors: Alexander KM , Dekker KH , Olding T , Schreiner LJ 
Published: January 2022

Abstract
In the clinic, routine quality assurance tests ensure the proper functioning of each individual aspect of a radiation therapy treatment delivery. However, these tests may not guarantee an accurate treatment delivery. In this work, we present the design and application of a head phantom (using 3D printing technology) developed for end-to-end quality assurance of a stereotactic radiation therapy treatment for brain metastases, coupled with inserts for ion chamber, and film and gel dosimeters. The head phantom was subjected to the entire clinical workflow, with each stage of the process being performed by the appropriate clinical personnel to ensure that this quality assurance test mimics the clinical scenario.
New directions for tetrazolium - gellan gum gel dosimeters
Authors: Penev Kalin I. , Mequanint Kibret 
Published: January 2022

Abstract
Tetrazolium salt-based dosimeters are non-diffusing, gel dosimeters with excellent physical and chemical stability but with relatively low dose sensitivity and a dose rate dependence of the dose response. Both issues are tackled in this study by: (a) the introduction of a new tetrazolium salt with simple synthesis and dose response around 585 nm which may provide the pathway to more sensitive formulations and (b) producing gels with low gellan gum concentration, thus limiting the dose rate effects, and addition of thickening agents to restrain the liquid loss (syneresis) from the resulting gels.
Effect of 60% thickness reduction of Sn-Cu solder alloy on localized micromechanical properties via nanoindentation approach
Authors: Mohd Yusoff F. A. , Bakar Maria Abu , Jalar Azman 
Published: January 2022

Abstract
The relationship between a process and mechanical properties are important in understanding the behaviour of a material under certain conditions. This indicate that mechanical properties of the materials can be modified through certain processing. Hence, this paper investigates the effect of 60% thickness reduction of Sn-Cu alloy in thermomechanical treatment on the localized micromechanical properties. A bar-shape of Sn-Cu solder alloy is subjected to heat treatment at 30°C, 60°C, 90°C, 120°C and 150°C for 20 minutes, followed by 60% thickness reduction via compression process. Sample without compression process was used as control sample. Nanoindentation approach was used to characterize the localized micromechanical properties of the samples. The results show the hardness value for control samples reduced approximately 56%, from 181 MPa at 30°C to 79 MPa at 150°C. Reduced modulus of control sample has shown similar decreasing trend from 149 GPa at 30°C to 85 GPa at 150°C, approximately 43% changes. Lower changes in hardness and reduced modulus observed for thermomechanical treated sample approximately 20% and 18%, respectively. These findings show that thermomechanical treatment has given significant effect on the localized micromechanical properties of Sn-Cu solder alloy.
The Effects of Acidic Secondary Dopants to the Electrical Conductivity of PEDOT: PSS Fabrics
Authors: Ruzaidi Dania Adila Ahmad , Suhaimi Fifi Alfiani , Saripudin Muhammad Adam , Ramli Rosmamuhamadani , Osman Hazwanee , Nadzri Nur Izzati Muhammad , Mahat Mohd Muzamir 
Published: January 2022

Abstract
Conductive polymers commonly used as fillers to enhance electrical properties of composite’s system. However, the low conductivity performance of conducting polymers, namely poly(3,4-ethylenedioxythiophene): poly (4-styrene sulfonate) (PEDOT: PSS), constrains their utilization in the field of conductive textile technology in inventing an advanced textiles’ fabric. Maintaining the stability of impregnated PEDOT: PSS fabrics at the microscopic level remains doubtful and unclear. Nowadays, researchers are actively pursuing the introduction of secondary dopants into PEDOT: PSS dispersion to overcome this challenge. In this study, a conductive PEDOT: PSS fabric via immersion technique was prepared and its effects on conductivity upon doped-secondarily by two different dopants; hydrochloric (HCl) and p-toluenesulfonic (p-TSA) acids was revealed. The volume percentage (vol.%) of the secondary dopants (1, 3, 5, 7, 9 vol.%) were varied to find the optimal vol.% for getting the great value of conductivity of the doped PEDOT: PSS fabrics. These fabrics were then analyzed by using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR), Electrochemical Impedance Spectroscopy (EIS), and Scanning Electron Microscopy (SEM) to investigate their conductivity performances chemically. It is found that the conductivity values were affected by varying the strength of the acids. It is concluded, that the 7 vol.% and 5 vol.% of HCl and p-TSA, respectively, gave the highest electrical conductivity values of the PEDOT: PSS fabrics. These findings can be used to provide direction and guidance to researchers in advancing the fields of textiles, electronics and advanced materials.
The Application of Natural Dye on Tinted Vehicle Films – A Review
Authors: Idris Siti Nursyakirah , Othman Siti Amira 
Published: January 2022

Abstract
The study present the utilization of natural dye from onion skin on tinted film. Tinted film for the car and helmet visor is produced from Polyethylene Terephthalate (PET) as the main material. However, tinted films that do not meet the Visible Light Transmission (VLT) values authorized for automobiles are being used by some people. Tinted films are also often manufactured using synthetic dyes, which have negative environmental impacts. Thus, the objective of this study was to prepare the tinted film for car and helmet visors that can comply with safety standards (MS1). Tinted film produced must comply with the percentage of VLT allowed which is 30%, 50% and 70%. Synthetic dyes, which are frequently used in the plastic manufacturing sector, will be substituted with natural colours in this study. PET is excellent for manufacturing plastic films because it has a number of benefits, including the ability to act as an amorphouse and semi-crystalline material. Natural dye extracted from onion skin is a good dye because there are Auxochrome groups. By choosing natural dyes over other options, we are helping to protect the environment and reducing human reliance on toxic chemicals.
Thermal cycling effect on the crack formation of solder joint in ball grid array package
Authors: Suhaimi M. F. , Abu Bakar M. , Jalar A. , Che Ani F. , Ramli M. R. 
Published: January 2022

Abstract
Ball grid array (BGA) technology is one of the technologies used in surface mount technology (SMT). It provides many interconnection points via the solder ball and thus give advantages such as good heat dissipation, improved the PCB design, BGA package become robust and reliable. In electronic industry, the reliability of BGA package is being concerned. Thermal cycling test (TCT)is one of typical reliability test used to investigate the reliability of the BGA package. This study investigates on the thermal cycling effect on the crack formation of solder joint in ball grid array package. The BGA package was subjected to thermal cycle test with temperature cyclic of -40°C and 85°C for 500, 750 and 1000 cycles. The finding shows that the cracks were observed in solder joint in 750 and 1000 cycles. This shows that the BGA package is sensitive to the thermal cycling and effect its reliability. The package was modified with adding underfill materials and tested through the same cycles. Cross sectional and Dye and pry test show no crack formation and dye penetration for all thermal cycles in the BGA package with underfill.
Microstructure Study of Mix Assembly Lead-free Sn-Ag-Cu Ball Grid Array and Sn-10Cu Solder Paste
Authors: Said Rita Mohd , Sulwarajan Kalaiarasi A/P , Razak Nurul Razliana Abdul , Somidin Flora , Zaimi Nur Syahirah Muhammad 
Published: January 2022

Abstract
In recent years, electronic technologies have been striving to minimize the use of lead in their manufacturing and production. As a result, the electronic packaging industry is slowly transitioning from lead solder to lead-free solder. Though environmentally lead-free solders are advantageous, there are still needs some work in meeting current technological demand and requirements. In this study, the microstructure analysis on lead-free Sn-Ag-Cu Ball Grid Array (BGA) and Sn10Cu solder paste was done. The main aim of this study is to investigate the effect of isothermal aging on the microstructure of the solder paste joint and evaluate the intermetallic compound (IMC) thickness on the solder joint reliability. Optical Microscope (OM) and ImageJ software have been utilized to study the bulk solder microstructure. The results show that the bulk microstructure consists of β-Sn and Cu6Sn5 / β-Sn eutectic phases. The IMC layer has undergone rapid growth with increasing aging temperature and time. The two main IMC layers (Cu3Sn and Cu6Sn5) grew thicker due to high temperature. The growth kinetic of Sn10Cu resulted in 16.70 kJ/mol activation level. Therefore, the significance of the findings from this study might provide a potential answer for future development for highly reliable solder joint applications.
The Influence of Indium, In on Microstructure Evolution During Isothermal Aging of Sn-0.7Cu
Authors: Ghazali Saidah Najihah Mohd , Sharif Nurulakmal Mohd 
Published: January 2022

Abstract
This paper reports influence of isothermal aging on bulk solder and the microstructure evolution of commercial Sn-0.7Cu (Sn-0.7Cu-0.05Ni+Ge) Pb-free solder alloy with addition of bismuth (Bi) and indium (In). Sn-0.7Cu, Sn-0.7Cu-1.0Bi, Sn-0.7Cu-1.0Bi-1.0In, Sn-0.7Cu-1.0Bi-4.0In, Sn-0.7Cu-1.0Bi-7.0 In solder alloys were prepared via casting process. The solder alloys were aged isothermally at 180°C for 500 hours and microstructure was compared with that of as-cast solder. Microstructure of bulk solder and melting temperatures were analysed via scanning electron microscopy, SEM and differential scanning calorimetry, DSC. The addition of In up to 7 wt% reduced the melting temperature from 231.1 to 218.5°C, and crystallisation temperature from 205.8 to 194.7°C with decreasing degree of undercooling which indicates that the In-added solder alloy had faster nucleation rate. Microstructure evaluation showed that as the amount of indium added increased to 7.0 wt%, the ß-Sn grains became smaller suggesting a refinement effect with In addition. Indium addition also encouraged the formation of Sn-In and Bi-In IMC which increased as the amount of In increased. These IMCs could potentially act as blocking mechanism for deformation leading to higher strength.
Influence of Copper Substrate Roughness on the Growth of Intermetallic Compounds Layer in SAC305 Solder Joints
Authors: Atiqah A. , Rahim R.A.A.A. , Jalar A. , Siow K. S. 
Published: January 2022

Abstract
This study aimed to evaluate the effect of surface morphology of copper (Cu) substrate on the intermetallic compound (IMC) growth and interfacial reactions when soldered with SAC305 lead-free solder during a thermal aging process. The surface morphology conditions of the Cu substrate influence the growth activity of the IMC layer. This study used different grits of silicon carbide (SiC) abrasive paper (400, 800 and 1200) to grind the Cu substrate to produce different surface roughness. The resulting Cu surface morphologies were examined using an infinite focus microscope (IFM), and the parameters used in this stereometric analysis were profile roughness. Hand soldering was used to melt the SAC305 solder on the Cu substrates with different surface roughness. Subsequently, the samples were subjected to an aging temperature of 150 °C for 800 hours to grow the IMC layers. Thermal aging increased the IMC thickness at the Cu-SAC305 interfaces. After thermal aging, the IMC layer thickness and related parameters were measured and analyzed with the IFM. The growth of the IMC layer thickness depended on the different surface morphology of the substrate when the aging temperatures and Cu materials were maintained in this study. In general, the IMC morphology for the rougher Cu substrate had a scallop-shaped and uniformed layer compared to those IMC from the smooth Cu substrate. The Cu substrate ground surface roughness with 400 grit SiC abrasive paper produced an average roughness, Ra
of 505.02 nm; this roughness produced the thinnest IMC layers compared to the different Cu substrates ground by SiC abrasive paper of different grits.
Preliminary investigation on the correlation between mechanical properties and conductivity of low-density polyethylene/carbon black (LDPE/CB) conductive polymer composite (CPC)
Authors: Badrul Farah , Abdul Halim Khairul Anwar , Mohd Salleh Mohd Arif Anuar , Omar Mohd Firdaus , Zakaria Azlin Fazlina , Muhamad Nor Asiah , Zakaria Muhammad Salihin 
Published: January 2022

Abstract
The insulating nature of a polymer can be changed to electrically conductive by incorporating conductive fillers within the polymer matrix to form a conductive polymer composite (CPC). One of the potential application of CPCs are in the area of flexible electronic interconnect application. Nevertheless, the correlation between the electrical conductivity and mechanical properties of CPCs such as tensile was found to be limited. Therefore, this paper is aimed to report the preliminary investigation on the correlation between conductivity and mechanical properties of a low-density polyethylene (LDPE) incorporation with conductive filler which is carbon black (CB. It was observed that the tensile strength was decreased by up to 29.4% and the elongation of break was decreased by up to 90.6% at higher CB loading compared to pure LDPE. Nonetheless, the modulus of elasticity and the electrical conductivity of the composites were increased by up to 150.5% and 16.4% at higher CB loading respectively. Moreover, it was found that the effect of CB additions on the tensile modulus was greater compared to the conductivity of the CPCs.
Comparison on oil and water absorption ability of various natural fiber
Authors: Mohamad Rosdi Mohamad Hilmi Hisyamuddin , Ahad Nor Azwin , Shahdan Dalila 
Published: January 2022

Abstract
The natural fibers from trees, agricultural waste, fruit skins and others will be considered as recyclable and recently have been used widely as filler materials in polymer composites. As an alternative, natural fibers have become the attention of researchers to substituate the commercial, synthetic and costly fibers. Therefore, this study has used 6 types of natural fibers from local fruit waste in Malaysia, and investigate the ability of each of them to absorb oil and water. All natural fiber showed different absorption percentage within the testing period. The natural fiber which more hydrophilic goes to coconut shell, againts peanuts as the lowest in absorbing water. Meanwhile, coconut residue capable to absorb more oil than coconut shell which showed oleophobic behaviour. The cellulose content, the hollow or pores and also the types of natural fiber are the factors that affect the percentage of oil and water uptake.