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Open Access Publications from the University of California

Scholarly Works (4 results)

  • Thesis
  • Peer Reviewed
UC Irvine Electronic Theses and Dissertations (2022)

Physiological signals contain a wealth of personal health information which needs continuous monitoring for early detection of disease-induced physiological irregularities and can be established as a potential approach to developing personalized healthcare devices. It has a very urgent need for the development of a new generation of convenient, low cost, reliable, and stable wearable devices to keep track on such critical signals in case of the firsthand notice of any abnormal changes indicating the pathological changes in our body.In the past decades, various categories of wearable sensors and platforms have been developed targeting the continuous, on-demand recordings of wide ranges of signals by different fabrication methods. Additive Manufacturing, also named three-dimensional (3D) printing has been developed in the past few years and received tremendous interest. It enables distributed manufacturing, allowing users to easily produce customized 3D objects in office or at home. In addition, additive manufacturing allows to reduce the production waste and energy consumption and possesses great potential to replace the conventional clean-room based fabrication technology with the potential of circumventing the requirement of sophisticated equipment and highly trained specialists. Moreover, it offers a broader range of material selection, and allows customization of the desired ink for different application purposes. Here, in this thesis, a series of application of 3D printing technology with different home developed nanomaterials in the development of the next generation of the wearable sensing platforms have been studied. In the first study, the physics behind the 3D printing process has been detailed analyzed and quantified the relationship between the different printing parameters to the final printed resolution. It helps the improvement of the reliability of the fabrication process by eliminating the unreliable trial and error method to optimize the required printing parameters. In the second study, an all-3D printed pressure sensor has been developed for radial artery pulse monitoring. Taking the advantaged of the material selection and preparation, all the ink shows good printability and strong mechanical properties. In addition, by carefully managing the printing path, direct 3D printed micropattern has been generated to enhance the sensor’s performance for subtle pressure detection. At last, the proposed all 3D printed pressure sensor exhibits high sensitivity and good mechanical property while mounting on human body, achieving reliable real-time biosignal recording. In the last study, a novel integrated sensing platform has been proposed. A triboelectric nanogenerator has been introduced as the power supply to remove the need of the battery, eliminating the potential drawbacks of the battery charging, replacement, and safety concerns. By careful selection of the materials, the two-dimensional (2D) MXene turns out to be the proper material satisfied the requirement of the conductivity, triboelectricity, and the extrusion printing capability. The performance of the 3D printed triboelectric nanogenerator has been well characterized, and the integrated sensing platform with the pressure sensor has been successfully demonstrated. Furthermore, a LED illustrator and an NFC antenna are added to the entire sensing platform to enable the direct visualization of the signal and real-time waveform recording. To the best of our knowledge, it is the first report of a wearable system for continuous and real-time physiological biosignals monitoring fully powered by human motion, signaling exciting potential in the field.

    Cover page: Investigation of nanomaterials in the wearable electronics for health monitoring
    • Article
    • Peer Reviewed
    UC Irvine Previously Published Works (2015)
    Freeman-Sheldon syndrome, or distal arthrogryposis type 2A (DA2A), is an autosomal-dominant condition caused by mutations in MYH3 and characterized by multiple congenital contractures of the face and limbs and normal cognitive development. We identified a subset of five individuals who had been putatively diagnosed with "DA2A with severe neurological abnormalities" and for whom congenital contractures of the limbs and face, hypotonia, and global developmental delay had resulted in early death in three cases; this is a unique condition that we now refer to as CLIFAHDD syndrome. Exome sequencing identified missense mutations in the sodium leak channel, non-selective (NALCN) in four families affected by CLIFAHDD syndrome. We used molecular-inversion probes to screen for NALCN in a cohort of 202 distal arthrogryposis (DA)-affected individuals as well as concurrent exome sequencing of six other DA-affected individuals, thus revealing NALCN mutations in ten additional families with "atypical" forms of DA. All 14 mutations were missense variants predicted to alter amino acid residues in or near the S5 and S6 pore-forming segments of NALCN, highlighting the functional importance of these segments. In vitro functional studies demonstrated that NALCN alterations nearly abolished the expression of wild-type NALCN, suggesting that alterations that cause CLIFAHDD syndrome have a dominant-negative effect. In contrast, homozygosity for mutations in other regions of NALCN has been reported in three families affected by an autosomal-recessive condition characterized mainly by hypotonia and severe intellectual disability. Accordingly, mutations in NALCN can cause either a recessive or dominant condition characterized by varied though overlapping phenotypic features, perhaps based on the type of mutation and affected protein domain(s).
      Cover page: De Novo Mutations in NALCN Cause a Syndrome Characterized by Congenital Contractures of the Limbs and Face, Hypotonia, and Developmental Delay
      • Article
      • Peer Reviewed
      UCLA Previously Published Works (2015)
      Multiple pterygium syndrome (MPS) is a phenotypically and genetically heterogeneous group of rare Mendelian conditions characterized by multiple pterygia, scoliosis, and congenital contractures of the limbs. MPS typically segregates as an autosomal-recessive disorder, but rare instances of autosomal-dominant transmission have been reported. Whereas several mutations causing recessive MPS have been identified, the genetic basis of dominant MPS remains unknown. We identified four families affected by dominantly transmitted MPS characterized by pterygia, camptodactyly of the hands, vertebral fusions, and scoliosis. Exome sequencing identified predicted protein-altering mutations in embryonic myosin heavy chain (MYH3) in three families. MYH3 mutations underlie distal arthrogryposis types 1, 2A, and 2B, but all mutations reported to date occur in the head and neck domains. In contrast, two of the mutations found to cause MPS in this study occurred in the tail domain. The phenotypic overlap among persons with MPS, coupled with physical findings distinct from other conditions caused by mutations in MYH3, suggests that the developmental mechanism underlying MPS differs from that of other conditions and/or that certain functions of embryonic myosin might be perturbed by disruption of specific residues and/or domains. Moreover, the vertebral fusions in persons with MPS, coupled with evidence of MYH3 expression in bone, suggest that embryonic myosin plays a role in skeletal development.
        Cover page: Autosomal-Dominant Multiple Pterygium Syndrome Is Caused by Mutations in MYH3
        • Article
        • Peer Reviewed
        UCLA Previously Published Works (2014)
        Elevated low-density lipoprotein cholesterol (LDL-C) is a treatable, heritable risk factor for cardiovascular disease. Genome-wide association studies (GWASs) have identified 157 variants associated with lipid levels but are not well suited to assess the impact of rare and low-frequency variants. To determine whether rare or low-frequency coding variants are associated with LDL-C, we exome sequenced 2,005 individuals, including 554 individuals selected for extreme LDL-C (>98(th) or <2(nd) percentile). Follow-up analyses included sequencing of 1,302 additional individuals and genotype-based analysis of 52,221 individuals. We observed significant evidence of association between LDL-C and the burden of rare or low-frequency variants in PNPLA5, encoding a phospholipase-domain-containing protein, and both known and previously unidentified variants in PCSK9, LDLR and APOB, three known lipid-related genes. The effect sizes for the burden of rare variants for each associated gene were substantially higher than those observed for individual SNPs identified from GWASs. We replicated the PNPLA5 signal in an independent large-scale sequencing study of 2,084 individuals. In conclusion, this large whole-exome-sequencing study for LDL-C identified a gene not known to be implicated in LDL-C and provides unique insight into the design and analysis of similar experiments.
          Cover page: Whole-Exome Sequencing Identifies Rare and Low-Frequency Coding Variants Associated with LDL Cholesterol
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