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Open Access Publications from the University of California

Scholarly Works (42 results)

  • Article
  • Peer Reviewed
LBL Publications (2019)
An atmospheric river (AR) event represents strong poleward moisture transport and is defined as a series of spatiotemporally connected instantaneous AR objects. Utilizing an AR tracking algorithm with a depth-first search (a widely used algorithm in computer science), we examine the life cycle characteristics of AR events that make landfall over the U.S. West Coast by their distinct origin locations. Landfalling AR events from the Northwest Pacific (120°E–170°W, WLAR events) temporally last longer (5.3 versus 3.6 days on average) and have stronger intensity of integrated vapor transport (508 versus 388 kg m−1 s−1 on average) than those originating from the Northeast Pacific (125°W–170°W, ELAR events). A persistent tripole geopotential height anomaly pattern over the North Pacific modulates the origin locations and propagation of landfalling AR events. WLAR events are associated with anomalous highs over northeastern Asia and the Northeast Pacific and an anomalous low over the central North Pacific. This pattern provides favorable conditions for WLAR events to start, propagate northeastward, and make landfall in the northwestern West Coast. WLAR events contribute approximately 25% of the total winter precipitation over Washington and British Columbia. ELAR events are associated with a similar tripole pattern to the WLAR events with an eastward shift. The anomalous low over the Northeast Pacific helps ELAR events to start, propagate northeastward, and make landfall in the southwestern West Coast. Precipitation induced by ELAR events contributes up to 30% of total winter precipitation over California.
    Cover page: Impact of Distinct Origin Locations on the Life Cycles of Landfalling Atmospheric Rivers Over the U.S. West Coast
    • Thesis
    • Peer Reviewed
    UCLA Electronic Theses and Dissertations (2022)

    Adoptive cell therapy, especially chimeric antigen receptor (CAR) therapy, has revolutionized cancer immunotherapy, showing remarkable results in the treatment of chronic viral infections and malignancies. Currently, there are six US Food and Drug Administration (FDA) approved adoptive CAR-engineered T (CAR-T) cell products for treating B cell lymphoma (BCL) or multiple myeloma (MM) patients: Yescarta (Kite Pharma, 2017), Kymriah (Novartis, 2017), Tecartus (Kite Pharma, 2020), Breyanzi (Bristol Myers Squibb, 2021), Abecma (Bristol Myers Squibb, 2021), and Carvykti (Legend, 2022).Despite the impressive outcomes, the current FDA-approved cell therapies fall into the autologous category: T cells obtained from the patient via leukapheresis and reinjected back into the same patient. This approach is high-cost, time-consuming, and patient-selective. Some patients may not have enough time waiting for the manufacturing to be completed. Therefore, new approaches that allow rapid production of large-scale and ready-to-use therapeutic cells are in great demand. The work presented in this thesis aims to provide alternative platforms for off- the-shelf cancer immunotherapy. By differentiating genetically engineered stem cells (i.e., ii hematopoietic stem cells and pluripotent stem cells), we developed multiple in vitro culture systems to robustly generate large-scale CAR-armed invariant nature killer T (NKT) cells suitable for allogeneic cell therapy. Chapter 1 introduces the background of iNKT cells, the-state-of-the-arts of stem cell engineering, and the previous study of engineering stem cell into iNKT cells. Chapter 2 reports a successful platform that utilizing artificial thymic organoid (ATO) culture methods to generate large-scale CAR-armed iNKT (CAR-iNKT) cells for cancer immunotherapy. The HSC-engineered iNKT cells closely resembled endogenous iNKT cells and exhibited potent antitumor efficacy and high safety in the xenograft multiple myeloma mouse model. Chapter 3 reports a feeder-free in vitro culture system to differentiate engineered stem cells into CAR-eNKT cells. The novel platform is robust and compatible for delivering different CAR cargos and additional molecules. The independence of murine derived feeder cells eliminates the potential risk of cross-species contamination during manufacturing. Chapter 4 switch the focus from previous chapters and starts to develop pluripotent stem cells (PSCs) derived CAR-iNKT cells for cancer immunotherapy. The unlimited expansion capability, capacity for clonal selection and ease of genetic engineering of PSCs allow them to be an ideal candidate providing unlimited source for off-the-shelf allogeneic cell therapies. Chapter 5 summarizes the thesis, discusses the challenge, and provides future perspectives for developing stem cell and iNKT-based off-the-shelf cancer immunotherapy. It is believed that more fundamental studies will be critical to further develop the next generation immunotherapy.

      Cover page: In vitro generation of large-scale CAR-iNKT cells from engineered human stem cells for off-the-shelf cancer immunotherapy
      • Article
      • Peer Reviewed
      UC Merced Previously Published Works (2021)
      A large literature suggests that the presence of refugees is associated with greater risk of conflict. We argue that the positive effects of hosting refugees on local conditions have been overlooked. Using global data from 1990 to 2018 on locations of refugee communities and civil conflict at the subnational level, we find no evidence that hosting refugees increases the likelihood of new conflict, prolongs existing conflict, or raises the number of violent events or casualties. Furthermore, we explore conditions where provinces are likely to experience substantively large decreases in conflict risk due to increased development. Analysis examining nighttime lights as a measure of development, coupled with expert interviews, support our claim. To address the possibility of selection bias, we use placebo tests and matching. Our research challenges assertions that refugees are security risks. Instead, we show that in many cases, hosting refugees can encourage local development and even conflict reduction.
        Cover page: Reexamining the Effect of Refugees on Civil Conflict: A Global Subnational AnalysisCreative Commons 'BY-NC-SA' version 4.0 license
        • Thesis
        • Peer Reviewed
        UCLA Electronic Theses and Dissertations (2012)

        MyTherapistMatch.com seeks to match visiting patients with suitable therapists after patients fill out the online questionnaire which consists of many psychological questions. However, a problem with this website is that many patients in fact do not end up scheduling a session with a therapist. The website founder believes that one of the major reasons is the length of the questionnaire. Therefore, to reduce annoyance for users, the task becomes selecting a subset of necessary questions from the questionnaire. The website provides patient selection data and patient action data which records how a patient interacts with a matched therapist. This thesis tries to implement hierarchical clustering method on both the question responses and the questions themselves, in order to find a reasonable way to pick the necessary questions. Correlation coefficients and Pearson's chi-squared test are used to define the metrics in hierarchical clustering. Satisfiable results are obtained. A linear model is also used to find the relationship between question responses and patient actions.

          Cover page: Cluster Analysis of Questionnaire Responses to MyTherapistMatch.com
          • Article
          • Peer Reviewed
          UC Berkeley Previously Published Works (2024)
          The catastrophic December 2022-January 2023 nine atmospheric rivers in California underscore the urgent need to better understand such high-risk weather extremes. Here we applied a machine learning clustering tool to understand the activity of atmospheric river clusters. Reanalysis results show that clusters with high density, that is the time fraction under atmospheric river conditions within a cluster, exhibit more frequent high-category atmospheric rivers, alongside an increased likelihood for extreme precipitation and severe land surface responses. The key circulation patterns of atmospheric river clusters are primarily attributed to subseasonal variability. Furthermore, the occurrence and density of atmospheric river clusters are modulated by the daily variability of the geopotential height field. Climate model projections suggest that atmospheric river clusters with higher density and higher categories will be more frequent as warming level increases. Our findings emphasize the important role of atmospheric river clusters in the development of climate adaptation and resilience strategies.
            Cover page: Back-to-back high category atmospheric river landfalls occur more often on the west coast of the United StatesCreative Commons 'BY' version 4.0 license
            • Article
            • Peer Reviewed
            UCLA Previously Published Works (2021)
              Creative Commons 'BY' version 4.0 license
              • Article
              • Peer Reviewed
              UC Berkeley Previously Published Works (2018)
              Calcium aluminate cement (CAC) has wide application in civil engineering and castable refractory materials. The main binding phases of hardened CAC paste, CaO·Al2O3·10H2O (CAH10), inevitably converts to 2CaO·Al2O3·8H2O (C2AH8), 3CaO·Al2O3·6H2O (C3AH6) and Al(OH)3 (AH3), leading to a significant change in the mechanical properties of the CAC matrix. This work investigates the mechanical properties of the main crystalline components in hydrated and/or converted CAC systems, using synchrotron-radiation-based high-pressure X-ray diffraction. The anisotropic deformations of CaAl2O4 (CA), CAH10 and C3AH6 along each crystallographic direction are investigated, along with their bulk moduli. The density-driven stiffening hypothesis is validated for the studied phases and other cement-based minerals. An atom-scale topological analysis is proposed to explain the unusually high stiffness of CAH10. The results provide fundamental information to understand the mechanical properties of single cement-based phases at molecular level, and enable predicting the changing mechanical properties of converted CAC matrix using homogenization models.
                • Article
                • Peer Reviewed
                UC Berkeley Previously Published Works (2022)
                Atmospheric rivers (ARs) are intensive poleward moisture transport events that are essential to the global hydrological cycle and are often linked to extreme weather events. We categorize the winter North Pacific ARs into two “flavors”: wind-dominated (windy ARs) and moisture-dominated (wet ARs) using 40 years of hourly data from fifth generation of the European Centre for Medium-Range Weather Forecasts Interim Reanalysis. We compare the differences between windy ARs and wet ARs including the lifecycle characteristics (such as genesis locations and changes of meteorological elements through the lifecycle), overall AR frequency, landfall impacts, and variability. The windy ARs are more likely to occur in the midlatitudes, while wet ARs are more active in the subtropics. Windy ARs are associated with intensive surface pressure lows, where the strong pressure gradient can support the strong wind within ARs. Due to larger size and longer lifetime, wet ARs are more likely to produce more precipitation over a lifecycle. By scaling the landfalling ARs, we show that wet ARs dominate the high-category ARs (Category 4 and 5) with higher spatial frequency and more precipitation, and windy ARs have higher contributions in the lower AR categories especially over British Columbia. Windy ARs are modulated by El Niño Southern Oscillation (ENSO) teleconnections via the anomalous geopotential height and extended subtropical jet. Wet ARs are affected by the anomalous sea surface temperature over the midlatitudes related to ENSO. Sensitivity analysis with an alternate AR detection algorithm shows consistent results on AR flavors but with disagreement on the amplitude.
                  Cover page: Characteristics and Variability of Winter Northern Pacific Atmospheric River FlavorsCreative Commons 'BY' version 4.0 license
                  • Article
                  • Peer Reviewed
                  UC Berkeley Previously Published Works (2020)
                    Cover page: Uncertainties in Atmospheric River Life Cycles by Detection Algorithms: Climatology and Variability
                    • Article
                    • Peer Reviewed
                    Research Grants Program Office (RGPO) Funded Publications (2023)
                    Cardiac pericytes are a critical yet enigmatic cell type within the coronary microvasculature. Since primary human cardiac pericytes are not readily accessible, we present a protocol to generate them from human induced pluripotent stem cells (hiPSCs). Our protocol involves several steps, including the generation of intermediate cell types such as mid-primitive streak, lateral plate mesoderm, splanchnic mesoderm, septum transversum, and epicardium, before deriving cardiac pericytes. With hiPSC-derived cardiac pericytes, researchers can decipher the mechanisms underlying coronary microvascular dysfunction. For complete details on the use and execution of this protocol, please refer to Shen et al.1.
                      Creative Commons 'BY-NC-ND' version 4.0 license
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