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Wirelessly activated device with an integrated ionic polymer metal composite (IPMC) cantilever valve for targeted drug delivery

Cheong HR, Nguyen NT, Khaw MK, Teoh BY, Chee PS

Lab Chip, 2018 10 09;18(20):3207-3215.
PMID: 30229248 DOI: 10.1039/c8lc00776d

This paper reports a wirelessly powered ionic polymer-metal composite (IPMC) soft actuator operated by external radio frequency (RF) magnetic fields for targeted drug delivery. A 183 μm thick IPMC cantilever valve was fitted with an embedded LC resonant circuit to wirelessly control the actuator when the field frequency is tuned to its resonant frequency of approximately 25 MHz. Experimental characterization of the fabricated actuator showed a cumulative cantilever deflection of 160 μm for three repeated RF ON-OFF cycles at 0.6 W input power. The device was loaded with a dye solution and immersed in DI water to demonstrate wireless drug release. The qualitative result shows the successful release of the dye solution from the device reservoir. The release rate can be controlled by tuning the RF input power. We achieved a maximum average release rate of ∼0.1 μl s-1. We further conducted an in vitro study with human tumor cells (HeLa) to demonstrate the proof of concept of the developed device. The experiments show promising results towards the intended drug delivery application.

Matched MeSH terms: Equipment Design
Fulltext Wireless displacement sensing of micromachined spiral-coil actuator using resonant frequency tracking

Ali MS, AbuZaiter A, Schlosser C, Bycraft B, Takahata K

Sensors (Basel), 2014 Jul 10;14(7):12399-409.
PMID: 25014100 DOI: 10.3390/s140712399

This paper reports a method that enables real-time displacement monitoring and control of micromachined resonant-type actuators using wireless radiofrequency (RF). The method is applied to an out-of-plane, spiral-coil microactuator based on shape-memory-alloy (SMA). The SMA spiral coil forms an inductor-capacitor resonant circuit that is excited using external RF magnetic fields to thermally actuate the coil. The actuation causes a shift in the circuit's resonance as the coil is displaced vertically, which is wirelessly monitored through an external antenna to track the displacements. Controlled actuation and displacement monitoring using the developed method is demonstrated with the microfabricated device. The device exhibits a frequency sensitivity to displacement of 10 kHz/µm or more for a full out-of-plane travel range of 466 µm and an average actuation velocity of up to 155 µm/s. The method described permits the actuator to have a self-sensing function that is passively operated, thereby eliminating the need for separate sensors and batteries on the device, thus realizing precise control while attaining a high level of miniaturization in the device.

Matched MeSH terms: Equipment Design/instrumentation
Fulltext Wideband LTE power amplifier with integrated novel analog pre-distorter linearizer for mobile wireless communications

Uthirajoo E, Ramiah H, Kanesan J, Reza AW

PLoS One, 2014;9(7):e101862.
PMID: 25033049 DOI: 10.1371/journal.pone.0101862

For the first time, a new circuit to extend the linear operation bandwidth of a LTE (Long Term Evolution) power amplifier, while delivering a high efficiency is implemented in less than 1 mm2 chip area. The 950 µm × 900 µm monolithic microwave integrated circuit (MMIC) power amplifier (PA) is fabricated in a 2 µm InGaP/GaAs process. An on-chip analog pre-distorter (APD) is designed to improve the linearity of the PA, up to 20 MHz channel bandwidth. Intended for 1.95 GHz Band 1 LTE application, the PA satisfies adjacent channel leakage ratio (ACLR) and error vector magnitude (EVM) specifications for a wide LTE channel bandwidth of 20 MHz at a linear output power of 28 dBm with corresponding power added efficiency (PAE) of 52.3%. With a respective input and output return loss of 30 dB and 14 dB, the PA's power gain is measured to be 32.5 dB while exhibiting an unconditional stability characteristic from DC up to 5 GHz. The proposed APD technique serves to be a good solution to improve linearity of a PA without sacrificing other critical performance metrics.

Matched MeSH terms: Equipment Design
Fulltext VitalQPlus: a potential screening tool for early diagnosis of COPD

Sui CF, Ming LC, Neoh CF, Ibrahim B

Int J Chron Obstruct Pulmon Dis, 2015;10:1613-22.
PMID: 26316735 DOI: 10.2147/COPD.S84618

Background: This study utilized a validated combination of a COPD Population Screener
(COPD-PS) questionnaire and a handheld spirometric device as a screening tool for patients at high risk of COPD, such as smokers. The study aimed to investigate and pilot the feasibility and application of this combined assessment, which we termed the “VitalQPlus”, as a screening tool for the early detection of COPD, especially in primary care settings.
Methods: This was a cross-sectional study screening potentially undiagnosed COPD patients using a validated five-item COPD-PS questionnaire together with a handheld spirometric device. Patients were recruited from selected Malaysian government primary care health centers.
Results: Of the total of 83 final participants, only 24.1% (20/83) were recruited from Perak and Penang (peninsular Malaysia) compared to 75.9% (63/83) from Sabah (Borneo region). Our dual assessment approach identified 8.4% of the surveyed patients as having potentially undiagnosed COPD. When only the Vitalograph COPD-6 screening tool was used, 15.8% of patients were detected with a forced expiratory volume in 1 second/forced expiratory volume in 6 seconds (FEV1/FEV6) ratio at <0.75, while 35.9% of patients were detected with the COPD-PS questionnaire. These findings suggested that this dual assessment approach has a greater chance of identifying potentially undiagnosed COPD patients compared to the Vitalograph COPD-6 or COPD-PS questionnaire when used alone. Our findings show that patients with more symptoms (scores of >=5) yielded twice the percentage of outcomes of FEV1/FEV6 <0.75 compared to patients with fewer COPD symptoms (scores <5).
Conclusion: With the availability of a simple screening questionnaire and the COPD-6, there is an opportunity easily to make patients more aware of their lung symptoms and to encourage the provision of early treatment. The proposed dual assessment approach, which we termed the VitalQPlus, may play a profound role in the early diagnosis of COPD, which is crucial in improving the clinical management of the disease.
Keywords: spirometry, pulmonary function test, chronic obstructive pulmonary disease,
airway obstruction

Matched MeSH terms: Equipment Design
Fulltext Via-less electromagnetic band-gap-enabled antenna based on textile material for wearable applications

Ashyap AYI, Elamin NIM, Dahlan SH, Abidin ZZ, See CH, Majid HA, et al.

PLoS One, 2021;16(1):e0246057.
PMID: 33508025 DOI: 10.1371/journal.pone.0246057

A compact fabric antenna structure integrated with electromagnetic bandgap structures (EBGs) covering the desired frequency spectrum between 2.36 GHz and 2.40 GHz for Medical Body-Area Networks (MBANs), is introduced. The needs of flexible system applications, the antenna is preferably low-profile, compact, directive, and robust to the human body's loading effect have to be satisfied. The EBGs are attractive solutions for such requirements and provide efficient performance. In contrast to earlier documented EBG backed antenna designs, the proposed EBG behaved as shielding from the antenna to the human body, reduced the size, and acted as a radiator. The EBGs reduce the frequency detuning due to the human body and decrease the back radiation, improving the antenna efficiency. The proposed antenna system has an overall dimension of 46×46×2.4 mm3. The computed and experimental results achieved a gain of 7.2 dBi, a Front to Back Ratio (FBR) of 12.2 dB, and an efficiency of 74.8%, respectively. The Specific Absorption Rate (SAR) demonstrates a reduction of more than 95% compared to the antenna without EBGs. Moreover, the antenna performance robustness to human body loading and bending is also studied experimentally. Hence, the integrated antenna-EBG is a suitable candidate for many wearable applications, including healthcare devices and related applications.

Matched MeSH terms: Equipment Design*
Fulltext Validation of a static Franz diffusion cell system for in vitro permeation studies

Ng SF, Rouse JJ, Sanderson FD, Meidan V, Eccleston GM

AAPS PharmSciTech, 2010 Sep;11(3):1432-41.
PMID: 20842539 DOI: 10.1208/s12249-010-9522-9

Over the years, in vitro Franz diffusion experiments have evolved into one of the most important methods for researching transdermal drug administration. Unfortunately, this type of testing often yields permeation data that suffer from poor reproducibility. Moreover, this feature frequently occurs when synthetic membranes are used as barriers, in which case biological tissue-associated variability has been removed as an artefact of total variation. The objective of the current study was to evaluate the influence of a full-validation protocol on the performance of a tailor-made array of Franz diffusion cells (GlaxoSmithKline, Harlow, UK) available in our laboratory. To this end, ibuprofen was used as a model hydrophobic drug while synthetic membranes were used as barriers. The parameters investigated included Franz cell dimensions, stirring conditions, membrane type, membrane treatment, temperature regulation and sampling frequency. It was determined that validation dramatically reduced derived data variability as the coefficient of variation for steady-state ibuprofen permeation from a gel formulation was reduced from 25.7% to 5.3% (n = 6). Thus, validation and refinement of the protocol combined with improved operator training can greatly enhance reproducibility in Franz cell experimentation.

Matched MeSH terms: Equipment Design
Fulltext Vacuum/compression valving (VCV) using parrafin-wax on a centrifugal microfluidic CD platform

Al-Faqheri W, Ibrahim F, Thio TH, Moebius J, Joseph K, Arof H, et al.

PLoS One, 2013;8(3):e58523.
PMID: 23505528 DOI: 10.1371/journal.pone.0058523

This paper introduces novel vacuum/compression valves (VCVs) utilizing paraffin wax. A VCV is implemented by sealing the venting channel/hole with wax plugs (for normally-closed valve), or to be sealed by wax (for normally-open valve), and is activated by localized heating on the CD surface. We demonstrate that the VCV provides the advantages of avoiding unnecessary heating of the sample/reagents in the diagnostic process, allowing for vacuum sealing of the CD, and clear separation of the paraffin wax from the sample/reagents in the microfluidic process. As a proof of concept, the microfluidic processes of liquid flow switching and liquid metering is demonstrated with the VCV. Results show that the VCV lowers the required spinning frequency to perform the microfluidic processes with high accuracy and ease of control.

Matched MeSH terms: Equipment Design
Using game controller as position tracking sensor for 3D freehand ultrasound imaging

Chan VS, Mohamed F, Yusoff YA, Dewi DEO, Anuar A, Shamsudin MA, et al.

Med Biol Eng Comput, 2020 May;58(5):889-902.
PMID: 31599379 DOI: 10.1007/s11517-019-02044-4

Position tracking has been widely used in medical applications, especially in 3D ultrasound imaging, where it has transformed the 2D slice limitation into 3D volume with bigger clinical impacts. As a game controller can also produce position tracking information, it has the potential to act as a low-cost and portable position tracker for ultrasound probes. This paper aims to investigate the feasibility of a game controller to perform as a position tracker and to design its implementation in 3D ultrasound imaging. The study consists of data acquisition and 3D ultrasound reconstruction for visualization. The data acquisition is accomplished by capturing the 2D ultrasound frame and its relative positional and orientation data by using an ultrasound probe and game controller respectively. These data are further reconstructed to produce 3D ultrasound volume for visualization. Our experiments include game controller position tracker testing and 3D ultrasound reconstruction on baby phantom. The results have confirmed that the game controller performance was closely aligned with that of in a robot arm. Also, the 3D ultrasound reconstruction implementation has revealed promising outcomes. With these features, the function of the currently available ultrasound probes can be prospectively improved using a game controller position tracker effectively. Graphical Abstract.

Matched MeSH terms: Equipment Design
Fulltext Urea and creatinine detection on nano-laminated gold thin film using Kretschmann-based surface plasmon resonance biosensor

Menon PS, Said FA, Mei GS, Berhanuddin DD, Umar AA, Shaari S, et al.

PLoS One, 2018;13(7):e0201228.
PMID: 30052647 DOI: 10.1371/journal.pone.0201228

This work investigates the surface plasmon resonance (SPR) response of 50-nm thick nano-laminated gold film using Kretschmann-based biosensing for detection of urea and creatinine in solution of various concentrations (non-enzymatic samples). Comparison was made with the presence of urease and creatininase enzymes in the urea and creatinine solutions (enzymatic samples), respectively. Angular interrogation technique was applied using optical wavelengths of 670 nm and 785 nm. The biosensor detects the presence of urea and creatinine at concentrations ranging from 50-800 mM for urea samples and 10-200 mM for creatinine samples. The purpose of studying the enzymatic sample was mainly to enhance the sensitivity of the sensor towards urea and creatinine in the samples. Upon exposure to 670 nm optical wavelength, the sensitivity of 1.4°/M was detected in non-enzymatic urea samples and 4°/M in non-enzymatic creatinine samples. On the other hand, sensor sensitivity as high as 16.2°/M in urea-urease samples and 10°/M in creatinine-creatininase samples was detected. The enhanced sensitivity possibly attributed to the increase in refractive index of analyte sensing layer due to urea-urease and creatinine-creatininase coupling activity. This work has successfully proved the design and demonstrated a proof-of-concept experiment using a low-cost and easy fabrication of Kretschmann based nano-laminated gold film SPR biosensor for detection of urea and creatinine using urease and creatininase enzymes.

Matched MeSH terms: Equipment Design
Fulltext Unilateral hypoglossal nerve palsy after the use of laryngeal mask airway (LMA) Protector

Tham LY, Beh ZY, Shariffuddin II, Wang CY

Korean J Anesthesiol, 2019 12;72(6):606-609.
PMID: 31304693 DOI: 10.4097/kja.d.18.00354

BACKGROUND: The laryngeal mask airway (LMAⓇ) ProtectorTM (Teleflex Medical Co., Ireland) is the latest innovation in the second generation of LMA devices. One distinguishing feature of this device is its integrated, color-coded cuff pressure indicator (Cuff PilotTM technology) which enables continuous cuff pressure monitoring and allows adjustments when necessary; this ensures patient safety due to better monitoring.
CASE: We report a case of postoperative unilateral hypoglossal nerve palsy after uncomplicated use of the LMA Protector. To the best of our knowledge, this could be the second reported case.
CONCLUSIONS: This case demonstrates that anesthetists need to routinely measure cuff pressure and that the Cuff PilotTM technology is not a panacea for potential cranial nerve injury after airway manipulation.

Matched MeSH terms: Equipment Design
Fulltext Ultralow Profile, Low Passive Intermodulation, and Super-Wideband Ceiling Mount Antennas for Cellular and Public Safety Distributed Antenna Systems

Ng KJ, Islam MT, Alevy AM, Mansor MF

Sensors (Basel), 2020 Apr 26;20(9).
PMID: 32357426 DOI: 10.3390/s20092456

This paper presents an ultralow profile, low passive intermodulation (PIM), and super-wideband in-building ceiling mount antenna that covers both the cellular and public safety ultra high frequency (UHF) band for distributed antenna system (DAS) applications. The proposed antenna design utilizes a modified 2-D planar discone design concept that is miniaturized to fit into a small disc-shaped radome. The 2-D planar discone has an elliptical-shaped disc monopole and a bell-shaped ground plane, a stub at the shorting path, with asymmetrical structure and an additional proximity coupling patch to maximize the available electrical path to support the 350 MHz band range. The proposed design maximizes the radome area with a reduction of about 62% compared to similar concept type antennas. Besides, the proposed design exhibits an improved radiation pattern with null reduction compared to a typical dipole/monopole when lies at the horizontal plane. A prototype was manufactured to demonstrate the antenna performance. The VSWR and radiation pattern results agreed with the simulated results. The proposed antenna achieves a band ratio of 28.57:1 while covering a frequency range of 350-10,000 MHz. The measured passive intermodulation levels are better than -150 dBc (2 × 20 Watts) for 350, 700 and 1920 MHz bands.

Matched MeSH terms: Equipment Design
Fulltext Ultra-low-voltage CMOS-based current bleeding mixer with high LO-RF isolation

Tan GH, Sidek RM, Ramiah H, Chong WK, Lioe de X

ScientificWorldJournal, 2014;2014:163414.
PMID: 25197694 DOI: 10.1155/2014/163414

This journal presents an ultra-low-voltage current bleeding mixer with high LO-RF port-to-port isolation, implemented on 0.13 μm standard CMOS technology for ZigBee application. The architecture compliments a modified current bleeding topology, consisting of NMOS-based current bleeding transistor, PMOS-based switching stage, and integrated inductors achieving low-voltage operation and high LO-RF isolation. The mixer exhibits a conversion gain of 7.5 dB at the radio frequency (RF) of 2.4 GHz, an input third-order intercept point (IIP3) of 1 dBm, and a LO-RF isolation measured to 60 dB. The DC power consumption is 572 µW at supply voltage of 0.45 V, while consuming a chip area of 0.97 × 0.88 mm(2).

Matched MeSH terms: Equipment Design/methods*
Two-week test-retest reliability of the Polar® RS800CX™ to record heart rate variability

Williams DP, Jarczok MN, Ellis RJ, Hillecke TK, Thayer JF, Koenig J

Clin Physiol Funct Imaging, 2017 Nov;37(6):776-781.
PMID: 26815165 DOI: 10.1111/cpf.12321

Recently, research has validated the use of Polar® heart rate monitors as a tool to index heart rate variability (HRV). In the current investigation, we sought to evaluate the test-retest reliability of both time and frequency domain measures of HRV using the Polar® RS800CX™ . Continuous HRV data were collected as 60 nominally healthy adults underwent a resting and orthostatic stress test. We evaluated reproducibility by means of the interclass correlation coefficient for absolute agreement and consistency, and the standard error of measurement. We found moderate reliable 2-week test-retest reliability of HRV using the Polar® RS800CX™ , results that are in line with previous studies that have validated the stability of HRV using other methods of measurement (e.g. electrocardiogram). Additionally, when examining different methods of spectral density estimation, we found that using the auto-regressive transformation method provides the most stable indices of HRV. Taken together, our results suggest that the Polar® RS800CX™ is not only a valid method to record HRV, but also a reliable one, particularly when using the auto-regressive transformation method.

Matched MeSH terms: Equipment Design
Tunable range enhancement of Brillouin-erbium fiber laser utilizing Brillouin pump pre-amplification technique

Al-Mansoori MH, Mahdi MA

Opt Express, 2008 May 26;16(11):7649-54.
PMID: 18545472

We demonstrate an enhanced multiwavelength L-band Brillouin-erbium fiber laser (BEFL), in which the Brillouin pump is pre-amplified before entering the single-mode fiber. The Brillouin pump pre-amplification provided by the Erbium-doped fiber has created higher intensity of Brillouin Stokes line generated in the single-mode fiber that leads to the homogenous gain saturation. Thus the built-up of self-lasing cavity modes is suppressed in a wider wavelength range. In contrary to the conventional linear-cavity BEFL, the number of output channels is enhanced within the same tuning range.

Matched MeSH terms: Equipment Design
Transtibial prosthetic socket pistoning: static evaluation of Seal-In(®) X5 and Dermo(®) Liner using motion analysis system

Gholizadeh H, Osman NA, Kamyab M, Eshraghi A, Abas WA, Azam MN

Clin Biomech (Bristol, Avon), 2012 Jan;27(1):34-9.
PMID: 21794965 DOI: 10.1016/j.clinbiomech.2011.07.004

The method of attachment of prosthesis to the residual limb (suspension) and socket fitting is a critical issue in the process of providing an amputee with prosthesis. Different suspension methods try to minimize the pistoning movement inside the socket. The Seal-In(®) X5 and Dermo(®) Liner by Ossur are new suspension liners that intend to reduce pistoning between the socket and liner. Since the effects of these new liners on suspension are unclear, the objective of this study was to compare the pistoning effect of Seal-In(®) X5 and Dermo(®) Liner by using Vicon Motion System.

Matched MeSH terms: Equipment Design
Transcatheter occlusion of native persistent ductus arteriosus using conventional Gianturco coils

Alwi M, Kang LM, Samion H, Latiff HA, Kandavel G, Zambahari R

Am J Cardiol, 1997 May 15;79(10):1430-2.
PMID: 9165178 DOI: 10.1016/s0002-9149(97)00160-4

Two hundred eleven patients with small- to moderate-sized native patent ductus arteriosus underwent closure using Gianturco coils, employing the transvenous multiple catheter approach. Short-term results showed a high rate of complete occlusion and a potential long-term complication of mild left pulmonary artery stenosis in a small number of patients.

Matched MeSH terms: Equipment Design
Transcatheter closure of muscular ventricular septal defect using the Amplatzer devices

Djer MM, Latiff HA, Alwi M, Samion H, Kandavello G

Heart Lung Circ, 2006 Feb;15(1):12-7.
PMID: 16473785

From November 1997 to June 2002, percutaneous transcatheter closure of muscular ventricular septal defects was attempted in seven patients. Four patients had single and three had multiple defects. Surgical closure was performed in two patients in an attempt to close a perimembranous defect, leaving behind a large apical muscular defect, which was successfully closed using a device in one patient, whilst the second patient succumbed to septicemia/endocarditis 3 weeks after failure of device implantation. One patient had previous pulmonary artery banding and in another intraoperative placement of two Clamshell devices followed by additional transcatheter closure using Gianturco coils in two different sessions was performed.

Matched MeSH terms: Equipment Design
Transabdominal fetal heart rate detection using NIR photopleythysmography: instrumentation and clinical results

Gan KB, Zahedi E, Mohd Ali MA

IEEE Trans Biomed Eng, 2009 Aug;56(8):2075-82.
PMID: 19403354 DOI: 10.1109/TBME.2009.2021578

In obstetrics, fetal heart rate (FHR) detection remains the standard for intrapartum assessment of fetal well-being. In this paper, a low-power (< 55 mW) optical technique is proposed for transabdominal FHR detection using near-infrared photoplesthysmography (PPG). A beam of IR-LED (890 nm) propagates through to the maternal abdomen and fetal tissues, resulting in a mixed signal detected by a low-noise detector situated at a distance of 4 cm. Low-noise amplification and 24-bit analog-to-digital converter resolution ensure minimum effect of quantization noise. After synchronous detection, the mixed signal is processed by an adaptive filter to extract the fetal signal, whereas the PPG from the mother's index finger is the reference input. A total of 24 datasets were acquired from six subjects at 37 +/- 2 gestational weeks. Results show a correlation coefficient of 0.96 (p-value < 0.001) between the proposed optical and ultrasound FHR, with a maximum error of 4%. Assessment of the effect of probe position on detection accuracy indicates that the probe should be close to fetal tissues, but not necessarily restricted to head or buttocks.

Matched MeSH terms: Equipment Design
Tracheal T-tube: a novel endoscopic insertion technique

Rahimah AN, Shahfi FI, Masaany M, Gazali N, Siti SH

J Laryngol Otol, 2016 Oct;130(10):967-968.
PMID: 27774924

Laryngotracheal stenosis is a complex condition of airway compromise involving either the larynx or trachea, or both.

Matched MeSH terms: Equipment Design
Fulltext Titanium Dioxide Nanoparticle-Based Interdigitated Electrodes: A Novel Current to Voltage DNA Biosensor Recognizes E. coli O157:H7

Nadzirah Sh, Azizah N, Hashim U, Gopinath SC, Kashif M

PLoS One, 2015;10(10):e0139766.
PMID: 26445455 DOI: 10.1371/journal.pone.0139766

Nanoparticle-mediated bio-sensing promoted the development of novel sensors in the front of medical diagnosis. In the present study, we have generated and examined the potential of titanium dioxide (TiO2) crystalline nanoparticles with aluminium interdigitated electrode biosensor to specifically detect single-stranded E.coli O157:H7 DNA. The performance of this novel DNA biosensor was measured the electrical current response using a picoammeter. The sensor surface was chemically functionalized with (3-aminopropyl) triethoxysilane (APTES) to provide contact between the organic and inorganic surfaces of a single-stranded DNA probe and TiO2 nanoparticles while maintaining the sensing system's physical characteristics. The complement of the target DNA of E. coli O157:H7 to the carboxylate-probe DNA could be translated into electrical signals and confirmed by the increased conductivity in the current-to-voltage curves. The specificity experiments indicate that the biosensor can discriminate between the complementary sequences from the base-mismatched and the non-complementary sequences. After duplex formation, the complementary target sequence can be quantified over a wide range with a detection limit of 1.0 x 10(-13)M. With target DNA from the lysed E. coli O157:H7, we could attain similar sensitivity. Stability of DNA immobilized surface was calculated with the relative standard deviation (4.6%), displayed the retaining with 99% of its original response current until 6 months. This high-performance interdigitated DNA biosensor with high sensitivity, stability and non-fouling on a novel sensing platform is suitable for a wide range of biomolecular interactive analyses.

Matched MeSH terms: Equipment Design

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