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Open Access Publications from the University of California

Scholarly Works (51 results)

  • Article
  • Peer Reviewed
UCLA Previously Published Works (2023)
Rapid developments in the coronavirus disease 2019 (COVID-19) mRNA vaccine showcased the power of lipid nanoparticle (LNP) delivery systems in fighting infectious diseases. In addition, mRNA therapeutics are also in development for cancer immunotherapy. Recently, mRNA therapy has been expanded to induce immune tolerance, the opposite of immune-boosting effects, to treat diseases involving enhanced immune responses including allergies and autoimmune diseases. mRNA LNPs have been used to treat peanut allergy by us and autoimmune experimental autoimmune encephalomyelitis by Ugur Sahin. It is expected that more and more research is going to delve into the immune tolerance field for allergies and autoimmune diseases, where effective therapies are in short supply.
    Cover page: mRNA lipid nanoparticles induce immune tolerance to treat human diseases.
    • Thesis
    • Peer Reviewed
    UCLA Electronic Theses and Dissertations (2020)

    Background

    The HIV epidemic among the older population is increasing. This study aims to identify challenges in expanding HIV testing, initiating antiretroviral therapy (ART), and retaining in care among people living with HIV (PLWH) aged 50 and older in Guangdong, China.

    Methods

    In the qualitative study for HIV testing, we conducted one-on-one in-depth interviews with 30 PLWH, and two focus group discussions with 12 care providers and 10 social workers. In the quantitative studies for initiation and retention, we used existing data of national cohorts derived from China’s national HIV and treatment system. Additional structural-level information of 63 ART clinics was collected via an online survey in the study for retention.

    Results

    The qualitative study highlighted challenges in four layers: 1) PLWH’s individual-layer barriers included a lack of basic knowledge, fear of HIV infection, a lack of social support, HIV discrimination, ageism, and fear of disclosure; 2) Care provider-layer obstacles were provider-patient age and gender concordance, unawareness of HIV infection among older adults, and limited time with patients; 3) a lack of involving social workers in HIV care was identified; 4) Institutional-layer challenges comprised less emphasis on post-screening counseling, deficiency in confidentiality and privacy, and workforce shortage.

    In the quantitative studies, among all 5,759 PLWH, 71% initiated ART at the end of the study. The median time to the first initiation was 35 days. ART initiation was associated with age, gender, residency, education levels, transmission modes, and testing sources. After adjusting for demographic covariates, initiation was associated with immune factors at the time of diagnosis. Among all 2,587 PLWH who initiated ART, 60% retained at the end of the study. ART retention was associated with age, testing sources, time to initiation since diagnosis, and routine education and counseling services in ART clinics.

    Conclusion

    PLWH, care providers, social workers, and policymakers should devote joint efforts to address challenges in expanding HIV testing services. Associated demographic factors may help identify older PLWH at higher risks of missing initiation and retention. The test-to-immediate-treatment policy, timely CD4 testing after diagnosis, and routine counseling and education need to be persistently implemented in the care continuum.

      Cover page: The HIV Continuum of Care among People Living with HIV Aged 50 and Older in Guangdong, China
      • Article
      • Peer Reviewed
      UC Santa Barbara Previously Published Works (2020)
      An amendment to this paper has been published and can be accessed via a link at the top of the paper.
        Cover page: Author Correction: Is negative capacitance FET a steep-slope logic switch?
        • Article
        • Peer Reviewed
        UC Santa Barbara Previously Published Works (2020)
        The negative-capacitance field-effect transistor(NC-FET) has attracted tremendous research efforts. However, the lack of a clear physical picture and design rule for this device has led to numerous invalid fabrications. In this work, we address this issue based on an unexpectedly concise and insightful analytical formulation of the minimum hysteresis-free subthreshold swing (SS), together with several important conclusions. Firstly, well-designed MOSFETs that have low trap density, low doping in the channel, and excellent electrostatic integrity, receive very limited benefit from NC in terms of achieving subthermionic SS. Secondly, quantum-capacitance is the limiting factor for NC-FETs to achieve hysteresis-free subthermionic SS, and FETs that can operate in the quantum-capacitance limit are desired platforms for NC-FET construction. Finally, a practical role of NC in FETs is to save the subthreshold and overdrive voltage losses. Our analysis and findings are intended to steer the NC-FET research in the right direction.
          Cover page: Is negative capacitance FET a steep-slope logic switch?Creative Commons 'BY' version 4.0 license
          • Article
          • Peer Reviewed
          UC Santa Barbara Previously Published Works (2020)
            Cover page: A Compact Current–Voltage Model for 2-D-Semiconductor-Based Lateral Homo-/Hetero-Junction Tunnel-FETs
            • Article
            • Peer Reviewed
            UC Santa Barbara Previously Published Works (2015)
            This paper introduces monolayer molybdenum disulfide (MoS2) based junction-less (JL) field-effect transistor (FET) and evaluates its performance at the smallest foreseeable (5.9 nm) transistor channel length as per the International Technology Roadmap for Semiconductors (ITRS), by employing rigorous quantum transport simulations. By comparing with MoS2 based conventional FETs, it is found that the JL structure naturally lends MoS2 FETs with superior device electrostatics, and higher ON-current for both high-performance and low-standby-power applications, especially at high impurity doping densities. Along with the advantages of the MoS2 JL-FETs, the effects of impurity scattering induced carrier mobility degradation of JL-FETs is also highlighted as a key technological issue to be addressed for exploiting their unique features.
              Cover page: Junction-Less Monolayer MoS2 FETsCreative Commons 'BY-NC-SA' version 4.0 license
              • Article
              • Peer Reviewed
              UC Santa Barbara Previously Published Works (2021)
              Abstract: Two-dimensional (2D) semiconducting materials, in particular transition-metal dichalcogenides, have emerged as the preferred channel materials for sub-5 nm field-effect transistors (FETs). However, the lack of practical doping techniques for these materials poses a significant challenge to designing complementary logic gates containing both n- and p-type FETs. Although electrical tuning of the polarity of 2D-FETs can potentially circumvent this problem, such devices suffer from the lack of balanced n- and p-mode transistor performance, forming one of the most enigmatic challenges of the reconfigurable 2D-FET technology. Here we provide a solution to this dilemma by judicious use of van der Waals (vdW) materials consisting of conductors, dielectrics and semiconductors forming a 50 nm thin quantum engineered strata that can guarantee a purely vdW-type interlayer interaction, which faithfully preserves the mid-gap contact design and thereby achieves an intrinsically mode-balanced and fully reconfigurable all-2D logic gate. The intrinsically mode-balanced gate eliminates the need for transistor sizing and allows post-fabrication reconfigurability to the transistor operation mode, simultaneously allowing an ultra-compact footprint and increased circuit functionality, which can be potentially exploited to build more area-efficient and low-cost integrated electronics for the internet of things (IoT) paradigm.
                Cover page: A mode-balanced reconfigurable logic gate built in a van der Waals strata
                • Article
                • Peer Reviewed
                UCSB Open Access Publishing Fund Supported Publications (2014)
                  Creative Commons 'BY' version 4.0 license
                  • Article
                  • Peer Reviewed
                  UCLA Previously Published Works (2021)
                  Aim: High turnover rates among service providers have burdened addiction treatment clinics and affected patient care and treatment outcome. In this study, we identified factors associated with providers’ turnover intention in Chinese methadone maintenance treatment (MMT) clinics. Subjects and methods: This study used the baseline data from a randomized controlled trial conducted in 68 MMT clinics in five provinces in China. Service providers’ turnover intention, perceived risk at work, job satisfaction, years working in the clinic as well as sociodemographic characteristics were collected in the assessment. A logistic mixed-effects model was used to identify factors associated with providers’ turnover intention. Results: Approximately one-third of these 418 service providers intended to change their job in this study. The findings of regression analysis showed that perceived risk at work was positively associated with the turnover intention (OR = 1.28; 95% CI: 1.17, 1.41) and job satisfaction was negatively related to the turnover intention (OR = 0.97; 95% CI: 0.95, 0.99). Conclusion: Study findings highlighted the importance of addressing service providers’ perceived risk at work and job satisfaction to reduce turnover intention. Intervention strategies that focus on occupation safety and job satisfaction could be integrated into current training programs to maintain a stable workforce in the MMT programs. Clinical trial registration details: This trial was registered at ClinicalTrials.gov. Registration date: January 4, 2013. Identifier: NCT01760720. Link: https://clinicaltrials.gov/ct2/show/NCT01760720.
                    Cover page: Turnover intention among service providers in Chinese methadone maintenance treatment clinics
                    • Article
                    • Peer Reviewed
                    UC Santa Barbara Previously Published Works (2021)
                      Cover page: 0.5T0.5R—An Ultracompact RRAM Cell Uniquely Enabled by van der Waals Heterostructures
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