Reduction of motion artifact in pulse oximetry by smoothed pseudo Wigner-Ville distribution

BACKGROUND: The pulse oximeter, a medical device capable of measuring blood oxygen saturation (SpO2), has been shown to be a valuable device for monitoring patients in critical conditions. In order to incorporate the technique into a wearable device which can be used in ambulatory settings, the influence of motion artifacts on the estimated SpO2 must be reduced. This study investigates the use of the smoothed psuedo Wigner-Ville distribution (SPWVD) for the reduction of motion artifacts affecting pulse oximetry. METHODS: The SPWVD approach is compared with two techniques currently used in this field, i.e. the weighted moving average (WMA) and the fast Fourier transform (FFT) approaches. SpO2 and pulse rate were estimated from a photoplethysmographic (PPG) signal recorded when subject is in a resting position as well as in the act of performing four types of motions: horizontal and vertical movements of the hand, and bending and pressing motions of the finger. For each condition, 24 sets of PPG signals collected from 6 subjects, each of 30 seconds, were studied with reference to the PPG signal recorded simultaneously from the subject's other hand, which was stationary at all times. RESULTS AND DISCUSSION: The SPWVD approach shows significant improvement (p < 0.05), as compared to traditional approaches, when subjects bend their finger or press their finger against the sensor. In addition, the SPWVD approach also reduces the mean absolute pulse rate error significantly (p < 0.05) from 16.4 bpm and 11.2 bpm for the WMA and FFT approaches, respectively, to 5.62 bpm. CONCLUSION: The results suggested that the SPWVD approach could potentially be used to reduce motion artifact on wearable pulse oximeters

Improved corrosion resistance of plasma carbon coated NiTi orthopedic materials

Nickel titanium (NiTi) alloys are useful in orthopedic applications because of their super-elastic properties and shape memory effects. However, when NiTi is used for a prolonged period of time, harmful Ni ions can leach out into the surrounding body fluid inside a human body, and so it is important to design a method to impede the out-diffusion of nickel from the materials into the biological medium. We aim at producing a barrier to mitigate the release of Ni ions during normal use. Carbon coatings have been shown to possess excellent bio-compatibility and good mechanical strength. In this work, amorphous hydrogenated DLC films with a graded C/NiTi interface were fabricated by plasma immersion ion implantation & deposition (PU & D) to provide such a barrier layer on NiTi. The elemental depth profiles and film thickness were determined by X-ray photoelectron spectroscopy (XPS) whereas the surface morphology was evaluated using atomic force microscopy (AFM). The film structure was studied by X-ray diffraction (XRD) and Raman spectroscopy. The corrosion resistance of the film was investigated using electrochemical tests based on ASTM G5-94. Compared to the control sample, the corrosion potential of the sample with the carbon coating changes from -250 to -50 mV and the film breakdown potential increases from 250 to 1200 mV. The corrosion current also diminishes from 10-6 to 10-7 A. The simulated body fluid (SBF) solutions after the electrochemical test were analyzed for Ni concentrations by inductively-coupled plasma mass spectrometry (ICPMS) and that data show that a much smaller amount of Ni has been released from the treated sample surface compared to the untreated control sample surface. Our results thus indicate that the deposited DLC film is effective in retarding the release of Ni ions from the bulk materials and more superior corrosion resistance is achieved based on our tests in a simulated fluid medium and at human body temperature.published_or_final_versio

An H5N1-based matrix protein 2 ectodomain tetrameric peptide vaccine provides cross-protection against lethal infection with H7N9 influenza virus

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Suppression of nickel out-diffusion from porous nickel-titanium shape memory alloy by plasma immersion ion implantation

Summary form only given. Porous nickel titanium is a promising material for medical application not only because of its super elasticity and shape memory effect but also the porous structure which may enhance bone growth due to the increased surface area. It is thus especially suitable for bone tissue in-growth and fixation of biomedical implants. However, like its dense counterpart, Ni leaching from the materials causes health concern. Thus, in order to suppress Ni diffusion from the materials to body fluids and tissues in humans, a diffusion barrier or similar structure must be introduced. In this work, we produced this diffusion barrier layer by oxygen or nitrogen plasma immersion ion implantation (PIII). In vitro tests were conducted by immersing the plasma-treated NiTi into simulated body fluid (SBF) at 37plusmn0.5degC for 5 weeks and the resulting SBF was analyzed for Ni and Ti using inductively-coupled plasma mass spectrometry (ICMPS). Our results show that Ni leaching is significantly mitigated by both nitrogen and oxygen PIII.published_or_final_versio

Nickel suppression in Ni-Ti alloys by plasma immersion ion implantation surface treatment: New materials for orthopaedic implantation

Conference Theme: Spinal Motion Segment: From Basic Science to Clinical Applicationpublished_or_final_versio

Pandemic A/H1N1 2009 Influenza Virus-like Particles Elicited Higher and Broader Immune Responses than the Commercial Panenza Vaccine

Objectives: The aim was to construct 2009 pandemic A/H1N1 influenza VLPs (virus-like particles) and compare the immunogenicity and protection efficacy with the commercial Panenza vaccine in BALB/c mouse model. Methods: VLPs derived from influenza A/Hong Kong/01/2009 (H1N1) virus were constructed by Bac-to-Bac baculovirus expression system. VLPs were purified by sucrose density gradient ultracentrifugation and then characterized by Western blotting analysis and transmission electron microscopy. After single dose vaccination with 3 µg of VLPs and equal amount of Panenza vaccine, the immune responses and efficacy of protection induced by VLPs were compared with those elicited by the Panenza vaccine in 6-8 week female BALB/c mice. Key findings: VLPs could induce higher antibody titer as determined by hemagglutinin inhibition and microneutralization assay. Furthermore, we demonstrated that VLPs induced better antibody response to neuraminidase. In addition, VLP vaccinated mice had stronger cell-mediated immune response. As a result, our VLPs conferred 100% protection while the Panenza vaccine only conferred 67% protection. Conclusion: From the results, we concluded that influenza VLPs are highly immunogenic and they are promising to be developed as an alternative strategy to vaccine production in order to control the spread of influenza viruses.published_or_final_versio

Consumption of dried fruit of Crataegus pinnatifida (hawthorn) suppresses high-cholesterol diet-induced hypercholesterolemia in rats

Author name used in this publication: Mabel Yin-Chun YauAuthor name used in this publication: Peter Hoi-Fu Yu2009-2010 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Yttrium-90 radioembolization for advanced inoperable hepatocellular carcinoma

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Three patients with homozygous familial hypercholesterolemia: Genomic sequencing and kindred analysis.

BackgroundHomozygous Familial Hypercholesterolemia (HoFH) is an inherited recessive condition associated with extremely high levels of low-density lipoprotein (LDL) cholesterol in affected individuals. It is usually caused by homozygous or compound heterozygous functional mutations in the LDL receptor (LDLR). A number of mutations causing FH have been reported in literature and such genetic heterogeneity presents great challenges for disease diagnosis.ObjectiveWe aim to determine the likely genetic defects responsible for three cases of pediatric HoFH in two kindreds.MethodsWe applied whole exome sequencing (WES) on the two probands to determine the likely functional variants among candidate FH genes. We additionally applied 10x Genomics (10xG) Linked-Reads whole genome sequencing (WGS) on one of the kindreds to identify potentially deleterious structural variants (SVs) underlying HoFH. A PCR-based screening assay was also established to detect the LDLR structural variant in a cohort of 641 patients with elevated LDL.ResultsIn the Caucasian kindred, the FH homozygosity can be attributed to two compound heterozygous&nbsp;LDLR damaging variants, an exon 12 p.G592E missense mutation and a novel 3kb exon 1 deletion. By analyzing the 10xG phased data, we ascertained that this deletion allele was most likely to have originated from a Russian ancestor. In the Mexican kindred, the strikingly elevated LDL cholesterol level can be attributed to a homozygous frameshift LDLR variant p.E113fs.ConclusionsWhile the application of WES can provide a cost-effective way of identifying the genetic causes of FH, it often lacks sensitivity for detecting structural variants. Our finding of the LDLR exon 1 deletion highlights the broader utility of Linked-Read WGS in detecting SVs in the clinical setting, especially when HoFH patients remain undiagnosed after WES