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Fulltext Development and implementation of a potential coronavirus disease 2019 (COVID-19) vaccine: A systematic review and meta-analysis of vaccine clinical trials

Sathian B, Asim M, Banerjee I, Roy B, Pizarro AB, Mancha MA, et al.

Nepal J Epidemiol, 2021 Mar;11(1):959-982.
PMID: 33868742 DOI: 10.3126/nje.v11i1.36163

Background: To date, there is no comprehensive systematic review and meta-analysis to assess the suitability of COVID-19 vaccines for mass immunization. The current systematic review and meta-analysis was conducted to evaluate the safety and immunogenicity of novel COVID-19 vaccine candidates under clinical trial evaluation and present a contemporary update on the development and implementation of a potential vaccines.
Methods: For this study PubMed, MEDLINE, and Embase electronic databases were used to search for eligible studies on the interface between novel coronavirus and vaccine design until December 31, 2020.
Results: We have included fourteen non-randomized and randomized controlled phase I-III trials. Implementation of a universal vaccination program with proven safety and efficacy through robust clinical evaluation is the long-term goal for preventing COVID-19. The immunization program must be cost-effective for mass production and accessibility. Despite pioneering techniques for the fast-track development of the vaccine in the current global emergency, mass production and availability of an effective COVID-19 vaccine could take some more time.
Conclusion: Our findings suggest a revisiting of the reported solicited and unsolicited systemic adverse events for COVID-19 candidate vaccines. Hence, it is alarming to judiciously expose thousands of participants to COVID-19 candidate vaccines at Phase-3 trials that have adverse events and insufficient evidence on safety and effectiveness that necessitates further justification.

Matched MeSH terms: Electronics
Fulltext Design, synthesis, and spasmolytic activity of thiophene-based derivatives via Suzuki cross-coupling reaction of 5-bromothiophene-2-carboxylic acid: their structural and computational studies

Rasool N, Ikram HM, Rashid A, Afzal N, Hashmi MA, Khan MN, et al.

Turk J Chem, 2020;44(5):1410-1422.
PMID: 33488240 DOI: 10.3906/kim-1911-51

In the current research work, a facile synthesis of a series of novel thiophene-based derivatives of 5-bromothiophene-2-carboxylic acid ( 1 ) have been synthesized. All analogs ( 5a - 5e , 10a - 10f ) were obtained from the coupling reaction of 5-bromothiophene-2-carboxylic acid ( 1 ) and different arylboronic acids with moderate-to-good yields under controlled and optimal conditions. The structures of the newly synthesized compounds were characterized through spectral analysis and their spasmolytic activity, and most of the compounds exhibited potentially good spasmolytic effect. Among the synthesized analogs, compound phenethyl 5-(3,4-dichlorophenyl)thiophene-2-carboxylate ( 10d ) particular showed an excellent spasmolytic effect with an EC 50 value of 1.26. All of the compounds were also studied for their structural and electronic properties by density functional theory (DFT) calculations. Through detailed insight into frontier molecular orbitals of the compounds and their different reactivity descriptors, it was found that the compounds 10c and 5c are the most reactive, while 10a is the most stable in the series. Furthermore, compounds 10c and 5c showed a very good NLO response with the highest β values.

Matched MeSH terms: Electronics
Fulltext Design of high speed and low offset dynamic latch comparator in 0.18 µm CMOS process

Rahman LF, Reaz MB, Yin CC, Ali MA, Marufuzzaman M

PLoS One, 2014;9(10):e108634.
PMID: 25299266 DOI: 10.1371/journal.pone.0108634

The cross-coupled circuit mechanism based dynamic latch comparator is presented in this research. The comparator is designed using differential input stages with regenerative S-R latch to achieve lower offset, lower power, higher speed and higher resolution. In order to decrease circuit complexity, a comparator should maintain power, speed, resolution and offset-voltage properly. Simulations show that this novel dynamic latch comparator designed in 0.18 µm CMOS technology achieves 3.44 mV resolution with 8 bit precision at a frequency of 50 MHz while dissipating 158.5 µW from 1.8 V supply and 88.05 µA average current. Moreover, the proposed design propagates as fast as 4.2 nS with energy efficiency of 0.7 fJ/conversion-step. Additionally, the core circuit layout only occupies 0.008 mm2.

Matched MeSH terms: Electronics, Medical/instrumentation
Fulltext Design of a MEMS-Based Oscillator Using 180nm CMOS Technology

Roy S, Ramiah H, Reza AW, Lim CC, Ferrer EM

PLoS One, 2016;11(7):e0158954.
PMID: 27391136 DOI: 10.1371/journal.pone.0158954

Micro-electro mechanical system (MEMS) based oscillators are revolutionizing the timing industry as a cost effective solution, enhanced with more features, superior performance and better reliability. The design of a sustaining amplifier was triggered primarily to replenish MEMS resonator's high motion losses due to the possibility of their 'system-on-chip' integrated circuit solution. The design of a sustaining amplifier observing high gain and adequate phase shift for an electrostatic clamp-clamp (C-C) beam MEMS resonator, involves the use of an 180nm CMOS process with an unloaded Q of 1000 in realizing a fixed frequency oscillator. A net 122dBΩ transimpedance gain with adequate phase shift has ensured 17.22MHz resonant frequency oscillation with a layout area consumption of 0.121 mm2 in the integrated chip solution, the sustaining amplifier draws 6.3mW with a respective phase noise of -84dBc/Hz at 1kHz offset is achieved within a noise floor of -103dBC/Hz. In this work, a comparison is drawn among similar design studies on the basis of a defined figure of merit (FOM). A low phase noise of 1kHz, high figure of merit and the smaller size of the chip has accredited to the design's applicability towards in the implementation of a clock generative integrated circuit. In addition to that, this complete silicon based MEMS oscillator in a monolithic solution has offered a cost effective solution for industrial or biomedical electronic applications.

Matched MeSH terms: Electronics, Medical*
Design and development of an automated, portable and handheld tablet personal computer-based data acquisition system for monitoring electromyography signals during rehabilitation

Ahamed NU, Sundaraj K, Poo TS

Proc Inst Mech Eng H, 2013 Mar;227(3):262-74.
PMID: 23662342

This article describes the design of a robust, inexpensive, easy-to-use, small, and portable online electromyography acquisition system for monitoring electromyography signals during rehabilitation. This single-channel (one-muscle) system was connected via the universal serial bus port to a programmable Windows operating system handheld tablet personal computer for storage and analysis of the data by the end user. The raw electromyography signals were amplified in order to convert them to an observable scale. The inherent noise of 50 Hz (Malaysia) from power lines electromagnetic interference was then eliminated using a single-hybrid IC notch filter. These signals were sampled by a signal processing module and converted into 24-bit digital data. An algorithm was developed and programmed to transmit the digital data to the computer, where it was reassembled and displayed in the computer using software. Finally, the following device was furnished with the graphical user interface to display the online muscle strength streaming signal in a handheld tablet personal computer. This battery-operated system was tested on the biceps brachii muscles of 20 healthy subjects, and the results were compared to those obtained with a commercial single-channel (one-muscle) electromyography acquisition system. The results obtained using the developed device when compared to those obtained from a commercially available physiological signal monitoring system for activities involving muscle contractions were found to be comparable (the comparison of various statistical parameters) between male and female subjects. In addition, the key advantage of this developed system over the conventional desktop personal computer-based acquisition systems is its portability due to the use of a tablet personal computer in which the results are accessible graphically as well as stored in text (comma-separated value) form.

Matched MeSH terms: Electronics, Medical
Fulltext Density Functional Theory Studies of the Electronic Structure and Muon Hyperfine Interaction in [Au25(SR)18]0 and [Au25(SeR)18]0 Nanoclusters

Ahmad SN, Zaharim WN, Sulaiman S, Hasan Baseri DF, Mohd Rosli NA, Ang LS, et al.

ACS Omega, 2020 Dec 29;5(51):33253-33261.
PMID: 33403287 DOI: 10.1021/acsomega.0c04937

Density functional theory computational investigation was performed to study the electronic structures, muon sites, and the associated hyperfine interactions in [Au25(SR)18]0 and [Au25(SeR)18]0 where R is phenylethane. The calculated electronic structures show inhomogeneous spin density distribution and are also affected by different ligands. The two most stable muon sites near Au atoms in the thiolated system are MAu11 and MAu6. When the thiolate ligands were replaced by selenolate ligands, the lowest energy positions of muons moved to MAu6 and MAu5. Muons prefer to stop inside the Au12 icosahedral shell, away from the central Au and the staple motifs region. Muonium states at phenyl ring and S/Se atoms in the ligand were found to be stable and the Fermi contact fields are much larger as compared to the field experienced by muons near Au atoms.

Matched MeSH terms: Electronics
Fulltext DeepMoney: counterfeit money detection using generative adversarial networks

Ali T, Jan S, Alkhodre A, Nauman M, Amin M, Siddiqui MS

PeerJ Comput Sci, 2019;5:e216.
PMID: 33816869 DOI: 10.7717/peerj-cs.216

Conventional paper currency and modern electronic currency are two important modes of transactions. In several parts of the world, conventional methodology has clear precedence over its electronic counterpart. However, the identification of forged currency paper notes is now becoming an increasingly crucial problem because of the new and improved tactics employed by counterfeiters. In this paper, a machine assisted system-dubbed DeepMoney-is proposed which has been developed to discriminate fake notes from genuine ones. For this purpose, state-of-the-art models of machine learning called Generative Adversarial Networks (GANs) are employed. GANs use unsupervised learning to train a model that can then be used to perform supervised predictions. This flexibility provides the best of both worlds by allowing unlabelled data to be trained on whilst still making concrete predictions. This technique was applied to Pakistani banknotes. State-of-the-art image processing and feature recognition techniques were used to design the overall approach of a valid input. Augmented samples of images were used in the experiments which show that a high-precision machine can be developed to recognize genuine paper money. An accuracy of 80% has been achieved. The code is available as an open source to allow others to reproduce and build upon the efforts already made.

Matched MeSH terms: Electronics
Fulltext DEVELOPMENT OF BATTERY MONITORING SYSTEM USING ARDUINO UNO MICROCONTROLLER

NURUL FITRIYAH ROSLAN, WAN MARIAM WAN MUDA

UMT Journal of Undergraduate Research, 2020;2(4):41-50.
MyJurnal

Battery Monitoring System (BMoS) is an electronic system that monitors rechargeable battery cells or packs with various parameters, such as battery voltage, current and State-of-Charge (SoC). This system can be used to avoid overcharging or over-discharging of batteries to increase its shelf life. However, BMoS on the market is very expensive and not suitable for low cost embedded systems. As the Arduino Uno is widely used for low cost microcontroller boards, easy programming environment, and open-source platforms for building electronic projects, therefore, this study focuses on Arduino Uno BMoS based system. This system consists of current and voltage sensors, an Arduino Uno microcontroller and a liquid crystal display (LCD). In order to develop this system, there are three objectives to be achieved. First, the relationship between input and output of the sensors must be derived mathematically. The mathematical expression obtained can be verified by connecting and disconnecting the circuit with load and monitoring the value of output sensors. Then, a complete prototype of the BMoS was developed by connecting the LCD, current and voltage sensors to the Arduino Uno microcontroller. The complete prototype was tested using an 11.1 V of Lithium-ion battery and a DC motor as a load. From the results, the current sensor shows zero value when no load is connected as no current flow. The LCD also displays 11.1V of battery voltage when fully charged. Using the developed system, the user can monitor the current, the voltage and the SoC of the battery to ensure the battery is not overcharged and overused. The development of the BMoS can help to monitor the operation and performance of the batteries in any electronic systems. At the end of this study, the complete BMoS prototype gives benefits to the user and makes work easier.

Matched MeSH terms: Electronics
Cytotoxicity of MXene-based nanomaterials for biomedical applications: A mini review

Lim GP, Soon CF, Ma NL, Morsin M, Nayan N, Ahmad MK, et al.

Environ Res, 2021 10;201:111592.
PMID: 34175291 DOI: 10.1016/j.envres.2021.111592

MXene based nanomaterial is an uprising two-dimensional material gaining tremendous scientific attentions due to its versatile properties for the applications in electronic devices, power generation, sensors, drug delivery, and biomedicine. However, the cytotoxic effects of MXene still remained a huge concern. Therefore, stringent analysis of biocompatibility of MXene is an essential requirement before introduction to human physiological system. Several in vitro and in vivo toxicological studies have been reported to investigate the interactions between MXenes with living organisms such as microbes, mammalian cells and animal models. The biological response and cytotoxicity reported were dependent on the physicochemical properties of MXene. The biocompatibility and cytotoxicity of MXene were dependent on size, dose, and surface coating. This review demystifies the in vitro and in vivo biocompatibility studies associated with MXene. Various methods proposed to mitigate the cytotoxicity of MXene for in vivo applications were revealed. The machine learning methods were developed to predict the cytotoxicity of experimentally synthesized MXene compounds. Finally, we also discussed the current research gaps of applying MXenes in biomedical interventions.

Matched MeSH terms: Electronics*
Cu-Doped SnO₂ Nanoparticles: Synthesis and Properties

Sagadevan S, Chowdhury ZZ, Johan MRB, Aziz FA, Roselin LS, Podder J, et al.

J Nanosci Nanotechnol, 2019 Nov 01;19(11):7139-7148.
PMID: 31039868 DOI: 10.1166/jnn.2019.16666

In this work, a simple, co-precipitation technique was used to prepare un-doped, pure tin oxide (SnO₂). As synthesized SnO₂ nanoparticles were doped with Cu2+ ions. Detailed characterization was carried out to observe the crystalline phase, morphological features and chemical constituents with opto-electrical and magnetic properties of the synthesized nanoparticles (NPs). X-ray diffraction analysis showed the existence of crystalline, tetragonal structure of SnO₂. Both the sample synthesized here showed different crystalline morphology. The band gap energy (Eg) of the synthesized sample was estimated and it was found to decrease from 3.60 to 3.26 eV. The band gap energy reduced due to increase in Cu2+ dopant amount inside the SnO₂ lattice. Optical properties were analyzed using absorption spectra and Photoluminescence (PL) spectra. It was observed that Cu2+ ions incorporated SnO₂ NPs exhibited more degradation efficiencies for Rhodamine B (RhB) dye compared to un-doped sample under UV-Visible irradiation. The dielectric characteristics of un-doped, pure and Cu2+ incorporated SnO₂ nanoparticles were studied at different frequency region under different temperatures. The ac conductivity and impedance analysis of pure and Cu2+ incorporated SnO₂ nanoparticles was also studied. The magnetic properties of the synthesized samples were analysed. Both the sample showed ferromagnetic properties. The research indicated that the Cu2+ ions doping can make the sample a promising candidate for using in the field of optoelectronics, magneto electronics, and microwave devices.

Matched MeSH terms: Electronics
Computational study of structural, optoelectronic and nonlinear optical properties of dynamic solid-state chalcone derivatives

Chaudhry AR, Irfan A, Muhammad S, Al-Sehemi AG, Ahmed R, Jingping Z

J Mol Graph Model, 2017 08;75:355-364.
PMID: 28651184 DOI: 10.1016/j.jmgm.2017.05.012

In the present study, we use the state of art density functional theory (DFT) techniques to calculate the structural, optoelectronic and nonlinear optical (NLO) properties for two novel chalcone derivatives. The geometrical structures of chalcone derivatives compound 1 and 2 are optimized using periodic boundary conditions (PBC) in solid-state phase as well as isolated single molecular geometry in the gas phase. The reasonable agreement is found among experimental, solid-state and gas phase single molecular geometries, which provide us, further confidence to explore the potential of above-entitled derivatives as good functional materials for electro-optical applications. For instance, the frequency dependent real parts of dielectric functions are calculated for compound 1 and 2. The maximum value of real part of the dielectric function for compound 1 and 2 at 0eV are computed as 4.35 and 6.68 for the polarization vectors of (001) directions, respectively, which reveals the fact that the compound 1 and 2 might be good charge transport materials. The reflectivities of the compound 1 and 2 are 0.64 and 0.45 revealing that the compound 2 might be more efficient material for organic photovoltaic (OPV) applications. The results of the refractive index improved by doping the strong electron withdrawing groups (EWGs) shows that the compound 2 might be good refractor of the photon as compared to compound 1. The calculated values for static second-order polarizability are 3498 and 10464 a. u. and for frequency dependent second harmonic generations are 2557 and 6429 a. u. for compound 1 and 2, respectively, which indicates their significant potential for possible nonlinear optical applications.

Matched MeSH terms: Electronics*
Chitin nanocrystals based complex fluids: A green nanotechnology

Kumar S, Foroozesh J

Carbohydr Polym, 2021 Apr 01;257:117619.
PMID: 33541647 DOI: 10.1016/j.carbpol.2021.117619

Chitin biopolymer has received significant attention recently by many industries as a green technology. Nanotechnology has been used to make chitin nanocrystals (ChiNCs) that are rod-shaped natural nanomaterials with nanoscale size. Owing to the unique features such as biodegradability, biocompatibility, renewability, rod-shape, and excellent surface and interfacial, physiochemical, and thermo-mechanical properties; ChiNCs have been green and attractive products with wide applications specifically in medical and pharmaceutical, food and packaging, cosmetic, electrical, and electronic, and also in the oil and gas industry. This review aims to give a comprehensive and applied insight into ChiNCs technology. It starts with reviewing different sources of chitin and their extraction methods followed by the characterization of ChiNCs. Furthermore, a detailed investigation into various complex fluids (dispersions, emulsions, foams, and gels) stabilized by ChiNCs and their characterisation have been thoroughly deliberated. Finally, the current status including ground-breaking applications, untapped investigations, and future prospective have been presented.

Matched MeSH terms: Electronics
Fulltext Characterization of the Fat Channel for Intra-Body Communication at R-Band Frequencies

Asan NB, Hassan E, Shah JVSRM, Noreland D, Blokhuis TJ, Wadbro E, et al.

Sensors (Basel), 2018 Aug 21;18(9).
PMID: 30134629 DOI: 10.3390/s18092752

In this paper, we investigate the use of fat tissue as a communication channel between in-body, implanted devices at R-band frequencies (1.7⁻2.6 GHz). The proposed fat channel is based on an anatomical model of the human body. We propose a novel probe that is optimized to efficiently radiate the R-band frequencies into the fat tissue. We use our probe to evaluate the path loss of the fat channel by studying the channel transmission coefficient over the R-band frequencies. We conduct extensive simulation studies and validate our results by experimentation on phantom and ex-vivo porcine tissue, with good agreement between simulations and experiments. We demonstrate a performance comparison between the fat channel and similar waveguide structures. Our characterization of the fat channel reveals propagation path loss of ∼0.7 dB and ∼1.9 dB per cm for phantom and ex-vivo porcine tissue, respectively. These results demonstrate that fat tissue can be used as a communication channel for high data rate intra-body networks.

Matched MeSH terms: Electronics/methods*
Fulltext Carbon-Based Nanomaterials/Allotropes: A Glimpse of Their Synthesis, Properties and Some Applications

Nasir S, Hussein MZ, Zainal Z, Yusof NA

Materials (Basel), 2018 Feb 13;11(2).
PMID: 29438327 DOI: 10.3390/ma11020295

Carbon in its single entity and various forms has been used in technology and human life for many centuries. Since prehistoric times, carbon-based materials such as graphite, charcoal and carbon black have been used as writing and drawing materials. In the past two and a half decades or so, conjugated carbon nanomaterials, especially carbon nanotubes, fullerenes, activated carbon and graphite have been used as energy materials due to their exclusive properties. Due to their outstanding chemical, mechanical, electrical and thermal properties, carbon nanostructures have recently found application in many diverse areas; including drug delivery, electronics, composite materials, sensors, field emission devices, energy storage and conversion, etc. Following the global energy outlook, it is forecasted that the world energy demand will double by 2050. This calls for a new and efficient means to double the energy supply in order to meet the challenges that forge ahead. Carbon nanomaterials are believed to be appropriate and promising (when used as energy materials) to cushion the threat. Consequently, the amazing properties of these materials and greatest potentials towards greener and environment friendly synthesis methods and industrial scale production of carbon nanostructured materials is undoubtedly necessary and can therefore be glimpsed as the focal point of many researchers in science and technology in the 21st century. This is based on the incredible future that lies ahead with these smart carbon-based materials. This review is determined to give a synopsis of new advances towards their synthesis, properties, and some applications as reported in the existing literatures.

Matched MeSH terms: Electronics
Fulltext Cannabis sativa subsp. sativa's pharmacological properties and health effects: A scoping review of current evidence

Lim XY, Tan TYC, Muhd Rosli SH, Sa'at MNF, Sirdar Ali S, Syed Mohamed AF

PLoS One, 2021;16(1):e0245471.
PMID: 33465140 DOI: 10.1371/journal.pone.0245471

INTRODUCTION: Hemp (Cannabis sativa subsp. sativa), commonly used for industrial purposes, is now being consumed by the public for various health promoting effects. As popularity of hemp research and claims of beneficial effects rises, a systematic collection of current scientific evidence on hemp's health effects and pharmacological properties is needed to guide future research, clinical, and policy decision making.
OBJECTIVE: To provide an overview and identify the present landscape of hemp research topics, trends, and gaps.
METHODS: A systematic search and analysis strategy according to the preferred reporting items for systematic review and meta-analysis-ScR (PRISMA-ScR) checklist on electronic databases including MEDLINE, OVID (OVFT, APC Journal Club, EBM Reviews), Cochrane Library Central and Clinicaltrials.gov was conducted to include and analyse hemp research articles from 2009 to 2019.
RESULTS: 65 primary articles (18 clinical, 47 pre-clinical) were reviewed. Several randomised controlled trials showed hempseed pills (in Traditional Chinese Medicine formulation MaZiRenWan) improving spontaneous bowel movement in functional constipation. There was also evidence suggesting benefits in cannabis dependence, epilepsy, and anxiety disorders. Pre-clinically, hemp derivatives showed potential anti-oxidative, anti-hypertensive, anti-inflammatory, anti-diabetic, anti-neuroinflammatory, anti-arthritic, anti-acne, and anti-microbial activities. Renal protective effects and estrogenic properties were also exhibited in vitro.
CONCLUSION: Current evidence on hemp-specific interventions are still preliminary, with limited high quality clinical evidence for any specific therapeutic indication. This is mainly due to the wide variation in test item formulation, as the multiple variants of this plant differ in their phytochemical and bioactive compounds. Future empirical research should focus on standardising the hemp plant for pharmaceutical use, and uniformity in experimental designs to strengthen the premise of using hemp in medicine.

Matched MeSH terms: Electronics
Fulltext Blockchain for Electronic Voting System-Review and Open Research Challenges

Jafar U, Aziz MJA, Shukur Z

Sensors (Basel), 2021 Aug 31;21(17).
PMID: 34502764 DOI: 10.3390/s21175874

Online voting is a trend that is gaining momentum in modern society. It has great potential to decrease organizational costs and increase voter turnout. It eliminates the need to print ballot papers or open polling stations-voters can vote from wherever there is an Internet connection. Despite these benefits, online voting solutions are viewed with a great deal of caution because they introduce new threats. A single vulnerability can lead to large-scale manipulations of votes. Electronic voting systems must be legitimate, accurate, safe, and convenient when used for elections. Nonetheless, adoption may be limited by potential problems associated with electronic voting systems. Blockchain technology came into the ground to overcome these issues and offers decentralized nodes for electronic voting and is used to produce electronic voting systems mainly because of their end-to-end verification advantages. This technology is a beautiful replacement for traditional electronic voting solutions with distributed, non-repudiation, and security protection characteristics. The following article gives an overview of electronic voting systems based on blockchain technology. The main goal of this analysis was to examine the current status of blockchain-based voting research and online voting systems and any related difficulties to predict future developments. This study provides a conceptual description of the intended blockchain-based electronic voting application and an introduction to the fundamental structure and characteristics of the blockchain in connection to electronic voting. As a consequence of this study, it was discovered that blockchain systems may help solve some of the issues that now plague election systems. On the other hand, the most often mentioned issues in blockchain applications are privacy protection and transaction speed. For a sustainable blockchain-based electronic voting system, the security of remote participation must be viable, and for scalability, transaction speed must be addressed. Due to these concerns, it was determined that the existing frameworks need to be improved to be utilized in voting systems.

Matched MeSH terms: Electronics
Fulltext Automatic frequency controller for power amplifiers used in bio-implanted applications: issues and challenges

Hannan MA, Hussein HA, Mutashar S, Samad SA, Hussain A

Sensors (Basel), 2014;14(12):23843-70.
PMID: 25615728 DOI: 10.3390/s141223843

With the development of communication technologies, the use of wireless systems in biomedical implanted devices has become very useful. Bio-implantable devices are electronic devices which are used for treatment and monitoring brain implants, pacemakers, cochlear implants, retinal implants and so on. The inductive coupling link is used to transmit power and data between the primary and secondary sides of the biomedical implanted system, in which efficient power amplifier is very much needed to ensure the best data transmission rates and low power losses. However, the efficiency of the implanted devices depends on the circuit design, controller, load variation, changes of radio frequency coil's mutual displacement and coupling coefficients. This paper provides a comprehensive survey on various power amplifier classes and their characteristics, efficiency and controller techniques that have been used in bio-implants. The automatic frequency controller used in biomedical implants such as gate drive switching control, closed loop power control, voltage controlled oscillator, capacitor control and microcontroller frequency control have been explained. Most of these techniques keep the resonance frequency stable in transcutaneous power transfer between the external coil and the coil implanted inside the body. Detailed information including carrier frequency, power efficiency, coils displacement, power consumption, supplied voltage and CMOS chip for the controllers techniques are investigated and summarized in the provided tables. From the rigorous review, it is observed that the existing automatic frequency controller technologies are more or less can capable of performing well in the implant devices; however, the systems are still not up to the mark. Accordingly, current challenges and problems of the typical automatic frequency controller techniques for power amplifiers are illustrated, with a brief suggestions and discussion section concerning the progress of implanted device research in the future. This review will hopefully lead to increasing efforts towards the development of low powered, highly efficient, high data rate and reliable automatic frequency controllers for implanted devices.

Matched MeSH terms: Electronics, Medical/methods*
Fulltext Application of artificial neural networks for the optimisation of wetting contact angle for lead free Bi-Ag soldering alloys

Nima Ghamarian, Azmah Hanim, M.A., Nahavandi, M., Zulkarnain Zainal, Lim, Hong Ngee

Pertanika Journal of Science & Technology, 2017;25(4):1255-1260.
MyJurnal

In the recent years, electronic packaging provides significant research and development challenges
across multiple disciplines such as performance, materials, reliability, thermals and interconnections.
New technologies and techniques frequently adopted can be implemented in soldering alloys of
semiconductor sectors in terms of optimisation. Wetting contact angle or wettability of solder alloys
is one of the important factors which has got the attention of scholars. Hence in this study, due to the
remarkable similarity over classical solder alloys (Pb-Sn), Bi-Ag solder was investigated. Data were
collected through the effects of aging time variation and different weight percentages of Ag in solder
alloys. The contact angle of the alloys with Cu plate was measured by optical microscopy. Artificial
neural networks (ANNs) were applied on the measured datasets to develop a numerical model for further
simulation. Results of the experiments and simulations showed that the coefficient of determination (R2
)
is around 0.97, which signifies that the ANN set up is appropriate for the evaluation.

Matched MeSH terms: Electronics
Fulltext Analysis of glass-reinforced epoxy material for radio frequency resonator

Zaman MR, Islam MT, Misran N, Yatim B

ScientificWorldJournal, 2014;2014:831435.
PMID: 24977230 DOI: 10.1155/2014/831435

A radio frequency (RF) resonator using glass-reinforced epoxy material for C and X band is proposed in this paper. Microstrip line technology for RF over glass-reinforced epoxy material is analyzed. Coupling mechanism over RF material and parasitic coupling performance is explained utilizing even and odd mode impedance with relevant equivalent circuit. Babinet's principle is deployed to explicate the circular slot ground plane of the proposed resonator. The resonator is designed over four materials from different backgrounds which are glass-reinforced epoxy, polyester, gallium arsenide (GaAs), and rogers RO 4350B. Parametric studies and optimization algorithm are applied over the geometry of the microstrip resonator to achieve dual band response for C and X band. Resonator behaviors for different materials are concluded and compared for the same structure. The final design is fabricated over glass-reinforced epoxy material. The fabricated resonator shows a maximum directivity of 5.65 dBi and 6.62 dBi at 5.84 GHz and 8.16 GHz, respectively. The lowest resonance response is less than -20 dB for C band and -34 dB for X band. The resonator is prototyped using LPKF (S63) drilling machine to study the material behavior.

Matched MeSH terms: Electronics/instrumentation*
Fulltext An overview of power electronics applications in fuel cell systems: DC and AC converters

Ali MS, Kamarudin SK, Masdar MS, Mohamed A

ScientificWorldJournal, 2014;2014:103709.
PMID: 25478581 DOI: 10.1155/2014/103709

Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter.

Matched MeSH terms: Electronics*

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