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Open Access Publications from the University of California

Scholarly Works (15 results)

  • Thesis
  • Peer Reviewed
UC San Diego Electronic Theses and Dissertations (2018)

Discovered by Segal and Bargmann in 1960s, the Segal--Bargmann trasnform is an important tool in mathematical physics, intertwining the Heisenberg and Fock pictures in quantum mechanics. We will discuss representations of the two-parameter {\em free} unitary Segal--Bargmann transform, which is the large-$N$ limit of Segal--Bargmann--Hall transform on unitary group. Motivated by a conditional expectation interpretation of the Segal-Bargmann transform, we derive the integral kernel for the large-$N$ limit of the two-parameter Segal-Bargmann-Hall transform over the unitary group, and explore its limiting behavior. We also extend the notion of circular systems to more general elliptic systems, giving an alternate construction of our new two-parameter {\em free} unitary Segal-Bargmann-Hall transform via a Biane-Gross-Malliavin type theorem.

    Cover page: The Segal--Bargmann transform in noncommutative probability
    • Thesis
    • Peer Reviewed
    UC San Diego Electronic Theses and Dissertations (2024)

    The utilization of metal-organic frameworks for adsorbing guest molecules has attracted significant research interests due to their diverse physical and chemical properties. The capture of atmospheric water and carbon dioxide holds particular importance in addressing challenges related to climate change. In this dissertation, we employ the many-body potential energy functions of water and carbon dioxide to investigate their thermodynamic and dynamic properties as they are adsorbed within several metal-organic frameworks using molecular dynamic simulations. Our investigations not only serve to validate our molecular models through the agreement of experimental and simulation observations but also offer valuable molecular insights that are challenging to attain through experimental approaches. Furthermore, this research contributes to the advancement of methodologies for modeling metal-organic frameworks and represents a significant reference in the computational exploration of guest molecules within metal-organic frameworks.

      Cover page: Exploring the Adsorption of Guest Molecules in Metal-Organic Frameworks: A Many-Body Formalism Approach
      • Article
      • Peer Reviewed
      UC Irvine Previously Published Works (2019)
      Extranasal cancers that metastasize to the sinonasal cavity are very rare. To date, there are only limited reports regarding this rare condition within the literature. Therefore, we retrospectively reviewed all patients diagnosed with metastatic cancer of the sinonasal tract from 2003 to 2018 at a tertiary academic medical center. Patient demographic data, clinical presentation, treatment modalities, and outcomes were investigated. There were a total of 17 patients (9 males and 8 females) included in the analysis. The mean age was 56.8 years (range 27-80). The most common primary malignancies were hepatocellular carcinoma (n = 3) and gastrointestinal tract adenocarcinoma (n = 3). The most common site of metastasis was the nasal cavity (n = 8). Five patients received radical tumor resection and the others underwent radiotherapy, chemotherapy, or combined chemoradiotherapy. The 2-year survival was 28%. In summary, metastasis to the sinonasal cavity remains extremely rare. A high degree of suspicion regarding the possibility of metastatic spread to the sinonasal region is necessary for patients with a previous history of malignancy who present with new sinonasal symptoms. The treatment strategy of sinonasal metastatic cancer is usually palliative therapy and the prognosis remains poor. However, early detection and diagnosis, coupled with aggressive treatment, may improve patient quality of life.
        Cover page: Metastatic Tumors of the Sinonasal Cavity: A 15-Year Review of 17 CasesCreative Commons 'BY' version 4.0 license
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2023)
        Metal-organic frameworks (MOFs) are a class of materials with diverse chemical and structural properties, and have been shown to effectively adsorb various types of guest molecules. The mechanism of water adsorption in NU-1500-Cr, a high-performance atmospheric water harvesting MOF, is investigated using a combination of molecular dynamics simulations and infrared spectroscopy. Calculations of thermodynamic and dynamical properties of water as a function of relative humidity allow for following the adsorption process from the initial hydration stage to complete filling of the MOF pores. Initial hydration begins at the water molecules that saturate the open Cr3+ sites of the framework, which is then followed by the formation of water chains that extend along the channels connecting the hexagonal pores of the framework. Water present in these channels gradually coalesces and fills the hexagonal pores sequentially after the channels are completely hydrated. The development of hydrogen-bond networks inside the MOF pores as a function of relative humidity is characterized at the molecular level using experimental and computational infrared spectroscopy. A detailed analysis of the OH-stretch vibrational band indicates that the low-frequency tail stems from strongly polarized hydrogen-bonded water molecules, suggesting the presence of some structural disorder in the experimental samples. Strategies for designing efficient water harvesting MOFs are also proposed based on the mechanism of water adsorption in NU-1500-Cr.
          Cover page: Structure and thermodynamics of water adsorption in NU-1500-Cr
          • Article
          • Peer Reviewed
          UC Irvine Previously Published Works (2019)
          Extranasal cancers that metastasize to the sinonasal cavity are very rare. To date, there are only limited reports regarding this rare condition within the literature. Therefore, we retrospectively reviewed all patients diagnosed with metastatic cancer of the sinonasal tract from 2003 to 2018 at a tertiary academic medical center. Patient demographic data, clinical presentation, treatment modalities, and outcomes were investigated. There were a total of 17 patients (9 males and 8 females) included in the analysis. The mean age was 56.8 years (range 27-80). The most common primary malignancies were hepatocellular carcinoma (n = 3) and gastrointestinal tract adenocarcinoma (n = 3). The most common site of metastasis was the nasal cavity (n = 8). Five patients received radical tumor resection and the others underwent radiotherapy, chemotherapy, or combined chemoradiotherapy. The 2-year survival was 28%. In summary, metastasis to the sinonasal cavity remains extremely rare. A high degree of suspicion regarding the possibility of metastatic spread to the sinonasal region is necessary for patients with a previous history of malignancy who present with new sinonasal symptoms. The treatment strategy of sinonasal metastatic cancer is usually palliative therapy and the prognosis remains poor. However, early detection and diagnosis, coupled with aggressive treatment, may improve patient quality of life.
            Cover page: Metastatic Tumors of the Sinonasal Cavity: A 15-Year Review of 17 Cases.
            • Article
            • Peer Reviewed
            UC Irvine Previously Published Works (2021)
            Invasive fungal rhinosinusitis (IFS) is a rare but often fatal disease. There are limited studies regarding IFS with orbital complications (IFSwOC). The present study aimed to identify the clinical signs associated with IFSwOC and prognosticators of the disease. A retrospective case series was conducted of patients histopathologically confirmed IFS or fungal rhinosinusitis with clinically apparent neuro-orbital complications who underwent surgery between 2008 and 2018. Demographic data, presenting symptoms and signs, culture data, laboratory results, and patient outcomes were obtained from medical records. A total of 38 patients were identified, including 9 patients with IFSwOC, and 29 patients with IFS without orbital complications (IFSsOC). The clinical signs associated with developing orbital complications include headache, fever, sphenoid sinus, or posterior ethmoid sinus involvement, CRP level ≥ 1.025 mg/dL, or ESR level ≥ 46.5 mm/h. In IFSwOC group, male, posterior ethmoid sinus involvement, WBC count ≥ 9000 μL, CRP level ≥ 6.91 mg/dL, or ESR level ≥ 69 mm/h were correlated with a significantly poorer prognosis. IFS patients with sphenoid or posterior ethmoid sinus involvement, headache or fever as presenting symptoms, elevated CRP, and ESR level were at risk of developing orbital complications. Timely surgical debridement followed by systemic antifungal treatment may improve treatment outcomes.
              Cover page: Invasive Fungal Rhinosinusitis with and without Orbital Complications: Clinical and Laboratory Differences
              • Article
              • Peer Reviewed
              UCLA Previously Published Works (2015)
              The Phr peptides of the Bacillus species mediate quorum sensing, but their identification and function in other species of bacteria have not been determined. We have identified a Phr peptide quorum-sensing system (TprA/PhrA) that controls the expression of a lantibiotic gene cluster in the Gram-positive human pathogen, Streptococcus pneumoniae. Lantibiotics are highly modified peptides that are part of the bacteriocin family of antimicrobial peptides. We have characterized the basic mechanism for a Phr-peptide signaling system in S. pneumoniae and found that it induces the expression of the lantibiotic genes when pneumococcal cells are at high density in the presence of galactose, a main sugar of the human nasopharynx, a highly competitive microbial environment. Activity of the Phr peptide system is not seen when pneumococcal cells are grown with glucose, the preferred carbon source and the most prevalent sugar encountered by S. pneumoniae during invasive disease. Thus, the lantibiotic genes are expressed under the control of both cell density signals via the Phr peptide system and nutritional signals from the carbon source present, suggesting that quorum sensing and the lantibiotic machinery may help pneumococcal cells compete for space and resources during colonization of the nasopharynx.
                Cover page: Phr‐peptide signaling by S. pneumoniae
                • Article
                • Peer Reviewed
                UC Irvine Previously Published Works (2019)
                Nasopharyngeal (NP) lymphoma is a rare primary malignancy of the head and neck and represents a minority of malignancies originating from the nasopharynx. For this reason, there are limited data regarding epidemiologic and treatment outcomes. This is a retrospective review of patients diagnosed with NP lymphoma from 1995 to 2017 at a tertiary medical center. The patients demographic data, clinical presentations, treatment modalities, Epstein-Barr virus (EBV)-encoded small RNA (EBER) staining, and outcomes were investigated. We considered a total of 35 patients, including 20 males and 15 females, diagnosed with NP lymphoma. The age ranged from 17 to 88 years (mean = 59.6). The common presentations were nasal obstruction, epistaxis, and neck mass. In our study, the most common pathological diagnosis of NP lymphoma was diffuse large B cell lymphoma (DLBCL) (n = 17), followed by NK/T cell lymphoma (NKTCL) (n = 9). Other pathologic diagnoses included extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALToma), small lymphocytic lymphoma, mantle cell lymphoma. There were 13 cases showing EBER positivity, including 7 cases of NKTCL, 5 cases of DLBCL, and 1 case of post-transplant lymphoproliferative disorder (PTLD). Most patients received chemotherapy alone, while some patients received both chemotherapy and radiotherapy. Seven patients had local recurrence, and fewer than half of the patients (n = 16) were alive at the time of the study (mean follow-up duration: 54.4 months). The five-year overall survival was 50.4%. NP lymphoma is very rare, and the most common pathologic type is DLBCL. EBER positivity is found in both NKTCL and DLBCL. Identifying more effective therapeutic agents is extremely important to improve patients survival.
                  Cover page: Nasopharyngeal Lymphoma: A 22-Year Review of 35 Cases.
                  • Article
                  • Peer Reviewed
                  UC Irvine Previously Published Works (2019)
                  Nasopharyngeal (NP) lymphoma is a rare primary malignancy of the head and neck and represents a minority of malignancies originating from the nasopharynx. For this reason, there are limited data regarding epidemiologic and treatment outcomes. This is a retrospective review of patients diagnosed with NP lymphoma from 1995 to 2017 at a tertiary medical center. The patients' demographic data, clinical presentations, treatment modalities, Epstein-Barr virus (EBV)-encoded small RNA (EBER) staining, and outcomes were investigated. We considered a total of 35 patients, including 20 males and 15 females, diagnosed with NP lymphoma. The age ranged from 17 to 88 years (mean = 59.6). The common presentations were nasal obstruction, epistaxis, and neck mass. In our study, the most common pathological diagnosis of NP lymphoma was diffuse large B cell lymphoma (DLBCL) (n = 17), followed by NK/T cell lymphoma (NKTCL) (n = 9). Other pathologic diagnoses included extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALToma), small lymphocytic lymphoma, mantle cell lymphoma. There were 13 cases showing EBER positivity, including 7 cases of NKTCL, 5 cases of DLBCL, and 1 case of post-transplant lymphoproliferative disorder (PTLD). Most patients received chemotherapy alone, while some patients received both chemotherapy and radiotherapy. Seven patients had local recurrence, and fewer than half of the patients (n = 16) were alive at the time of the study (mean follow-up duration: 54.4 months). The five-year overall survival was 50.4%. NP lymphoma is very rare, and the most common pathologic type is DLBCL. EBER positivity is found in both NKTCL and DLBCL. Identifying more effective therapeutic agents is extremely important to improve patients' survival.
                    Cover page: Nasopharyngeal Lymphoma: A 22-Year Review of 35 CasesCreative Commons 'BY' version 4.0 license
                    • Article
                    • Peer Reviewed
                    UCLA Previously Published Works (2022)
                    Sport-related concussion (SRC) is an important public health issue. White-matter alterations after SRC are widely studied by neuroimaging approaches, such as diffusion magnetic resonance imaging (MRI). Although the exact anatomical location of the alterations may differ, significant white-matter alterations are commonly observed in long fiber tracts, but are never proven. In the present study, we performed streamline tractography to characterize the association between tract length and white-matter microstructural alterations after SRC. Sixty-eight collegiate athletes diagnosed with acute concussion (24-48 h post-injury) and 64 matched contact-sport controls were included in this study. The athletes underwent diffusion tensor imaging (DTI) in 3.0 T MRI scanners across three study sites. DTI metrics were used for tract-based spatial statistics to map white-matter regions-of-interest (ROIs) with significant group differences. Whole-brain white-mater streamline tractography was performed to extract affected white-matter streamlines (i.e., streamlines passing through the identified ROIs). In the concussed athletes, streamline counts and DTI metrics of the affected white-matter fiber tracts were summarized and compared with unaffected white-matter tracts across tract length in the same participant. The affected white-matter tracts had a high streamline count at length of 80-100 mm and high length-adjusted affected ratio for streamline length longer than 80 mm. DTI mean diffusivity was higher in the affected streamlines longer than 100 mm with significant associations with the Brief Symptom Inventory score. Our findings suggest that long fibers in the brains of collegiate athletes are more vulnerable to acute SRC with higher mean diffusivity and a higher affected ratio compared with the whole distribution.
                      Cover page: Effects of White-Matter Tract Length in Sport-Related Concussion: A Tractography Study from the NCAA-DoD CARE Consortium.
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