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Open Access Publications from the University of California

Scholarly Works (66 results)

  • Article
Contemporary Music Score Collection (2020)
This music score was submitted for the Kaleidoscope 2020 Call for Scores, an open access collaboration with the UCLA Music Library.
    Cover page: Carbon-Based
    • Thesis
    • Peer Reviewed
    UC Berkeley Electronic Theses and Dissertations (2021)

    Wave energy converter "wave carpet" is an artificial flexible structure originally introduced and actively developed by the Theoretical and Applied Fluid Dynamics Laboratory (TAFLab) for nearly a decade. Wave carpet is submerged on shallow-water seabed and absorbs the energy of incoming surface waves. Several studies conducted by TAFLab members numerically and experimentally proved its concept and supported its technical feasibility.

    Inheriting from the previous works, this thesis further extends the understanding of wave carpet by numerically investigating one of its possible configurations and heuristically optimizing its planar shape. The study concentrates on arbitrary-shaped wave carpet locally embedded on the seafloor. This type of wave carpet is simplified into a visco-elastic part of the surrounding rigid seabed. In order to prepare the simulation environment, we first solve the problem of wave-viscoelastic seabed interaction using the High-Order Spectral (HOS) method. As a result, the solution presents the propagation of periodic waves over the entire visco-elastic ocean bottom. Wave carpet is subsequently limited to a partial seafloor, and the simulation domain is repetitively wave-fed and marched over time by Runge-Kutta method. Eventually, the procedure results in a robust numerical model of a wave tank with a wave carpet of an arbitrary shape. The model is validated against several criteria to ensure its correctness. It is referred to as the HORSK model that resembles a wave tank.

    The HOSRK wave tank is numerically stable, three-dimensional and possibly highly nonlinear. It serves as a computational environment simulating the real-world scenarios in which incoming waves propagate over a wave carpet and damp out. Through many experiments with the numerical wave tank, we find the optimal water deepness and the optimal restoring force and damping ratio, two main characteristics of the wave carpet, for the maximum energy absorption. We further investigate a wide range of linear and nonlinear elliptical wave carpets, and we find that toward the optimal point the difference between linear and nonlinear carpets in terms of energy absorption is subtle.

    To optimize the wave carpet shape, we propose the Neural Network-based optimization method for linear optimization and the Genetic Algorithm for nonlinear optimization. The results show that in most wave cases the optimal-shaped carpets can absorb approximately twice more energy than the baseline circular shape, and the nonlinear optimal shapes are very similar to the linear optimal ones.

      Cover page: Nonlinear Investigation and Shape Optimization of Wave Energy Converter "Wave Carpet"
      • Article
      • Peer Reviewed
      UC Berkeley Previously Published Works (2020)
      The core of human connection is embodied action, with synchrony, coordinated movement, and affective attunement through the body present from infancy. Yet whereas all students have the capacity for co-presence, a common focus of formal educational institutions on spoken language for interaction makes communication inaccessible to some students, thus impeding their participation in learning. As such, toward providing resources for nonverbal autistic students we must ask: How do we design for inclusive social participation of students with diverse interactional modalities? This paper outlines the development of an embodied-design solution that centers the dynamic body as the nexus of social interaction, thus reclaiming the natural versatility of multimodal interpersonal communication. The Magical Musical Mat is a domain-general platform that allows people to interact through the non-speaking modalities of touch and sound. It removes interactional asymmetry between diverse interlocutors and surfaces the basic human need and capacity to connect with one another, in school and beyond.
        Cover page: Being in touch with the core of social interaction: Embodied-design for the nonverbal
        • Article
        • Peer Reviewed
        UC Irvine Previously Published Works (2023)
        Digestion is driven by digestive enzymes and digestive enzyme gene copy number can provide insights on the genomic underpinnings of dietary specialization. The Adaptive Modulation Hypothesis (AMH) proposes that digestive enzyme activity, which increases with increased gene copy number, should correlate with substrate quantity in the diet. To test the AMH and reveal some of the genetics of herbivory vs carnivory, we sequenced, assembled, and annotated the genome of Anoplarchus purpurescens, a carnivorous prickleback fish in the family Stichaeidae, and compared the gene copy number for key digestive enzymes to that of Cebidichthys violaceus, a herbivorous fish from the same family. A highly contiguous genome assembly of high quality (N50 = 10.6 Mb) was produced for A. purpurescens, using combined long-read and short-read technology, with an estimated 33,842 protein-coding genes. The digestive enzymes that we examined include pancreatic α-amylase, carboxyl ester lipase, alanyl aminopeptidase, trypsin, and chymotrypsin. Anoplarchus purpurescens had fewer copies of pancreatic α-amylase (carbohydrate digestion) than C. violaceus (1 vs. 3 copies). Moreover, A. purpurescens had one fewer copy of carboxyl ester lipase (plant lipid digestion) than C. violaceus (4 vs. 5). We observed an expansion in copy number for several protein digestion genes in A. purpurescens compared to C. violaceus, including trypsin (5 vs. 3) and total aminopeptidases (6 vs. 5). Collectively, these genomic differences coincide with measured digestive enzyme activities (phenotypes) in the two species and they support the AMH. Moreover, this genomic resource is now available to better understand fish biology and dietary specialization.
          Cover page: The genome of Anoplarchus purpurescens (Stichaeidae) reflects its carnivorous diet.
          • Article
          • Peer Reviewed
          UC Irvine Previously Published Works (2018)

          Objective

          The primary endpoints of this study were long-term weight loss, morbidity, and changes in comorbidities and quality of life.

          Background

          Bariatric surgery is an effective option for the treatment of severe obesity and its related comorbidities. However, few studies have reported on the long-term outcome (>5 yrs) of bariatric surgery.

          Methods

          Between 2002 and 2007, 250 patients with a body mass index (BMI) of 35 to 60 kg/m were randomly assigned to undergo laparoscopic gastric bypass or laparoscopic gastric banding. After exclusions, 111 patients underwent gastric bypass and 86 patients underwent gastric banding. Factors predictive of improved weight loss were analyzed using multiple logistic regressions.

          Results

          At baseline, the mean age was 43 ± 10 years and the mean BMI was 46.5 ± 5.6 kg/m. At 10-year follow-up, the mean total body weight loss for the entire cohort was -37.5 ± 19.4 kg, -42.4 ± 19.6 kg for gastric bypass versus -27.4 ± 14.5 kg for gastric banding. Late reoperation was significantly higher after gastric banding compared with the gastric bypass group (31.4% vs. 8.1%, respectively, P < 0.01). For the entire cohort, improvement or remission of diabetes occurred in 68%; 61% for hypertension; and 57% for dyslipidemia. The long-term mortality for the entire cohort was 1.0% at a mean follow-up of 9.5 ± 0.4 years. Factors predictive of improved weight loss included the type of operation (ie, gastric bypass), female sex, and the absence of diabetes at baseline. At long-term follow-up, quality of life continues to be improved from baseline for both the groups.

          Conclusions

          Bariatric surgery is an effective treatment for severe obesity with durable 10-year weight loss and improvement in comorbidities and quality of life. Compared with gastric banding, gastric bypass was associated with better long-term weight loss, lower rate of late reoperation, and improved remission of comorbidities.
            Cover page: Ten-year Outcomes of a Prospective Randomized Trial of Laparoscopic Gastric Bypass Versus Laparoscopic Gastric Banding
            • Article
            • Peer Reviewed
            UC Irvine Previously Published Works (2018)

            Objective

            The primary endpoints of this study were long-term weight loss, morbidity, and changes in comorbidities and quality of life.

            Background

            Bariatric surgery is an effective option for the treatment of severe obesity and its related comorbidities. However, few studies have reported on the long-term outcome (>5 yrs) of bariatric surgery.

            Methods

            Between 2002 and 2007, 250 patients with a body mass index (BMI) of 35 to 60 kg/m were randomly assigned to undergo laparoscopic gastric bypass or laparoscopic gastric banding. After exclusions, 111 patients underwent gastric bypass and 86 patients underwent gastric banding. Factors predictive of improved weight loss were analyzed using multiple logistic regressions.

            Results

            At baseline, the mean age was 43 ± 10 years and the mean BMI was 46.5 ± 5.6 kg/m. At 10-year follow-up, the mean total body weight loss for the entire cohort was -37.5 ± 19.4 kg, -42.4 ± 19.6 kg for gastric bypass versus -27.4 ± 14.5 kg for gastric banding. Late reoperation was significantly higher after gastric banding compared with the gastric bypass group (31.4% vs. 8.1%, respectively, P < 0.01). For the entire cohort, improvement or remission of diabetes occurred in 68%; 61% for hypertension; and 57% for dyslipidemia. The long-term mortality for the entire cohort was 1.0% at a mean follow-up of 9.5 ± 0.4 years. Factors predictive of improved weight loss included the type of operation (ie, gastric bypass), female sex, and the absence of diabetes at baseline. At long-term follow-up, quality of life continues to be improved from baseline for both the groups.

            Conclusions

            Bariatric surgery is an effective treatment for severe obesity with durable 10-year weight loss and improvement in comorbidities and quality of life. Compared with gastric banding, gastric bypass was associated with better long-term weight loss, lower rate of late reoperation, and improved remission of comorbidities.
              Cover page: Ten-year Outcomes of a Prospective Randomized Trial of Laparoscopic Gastric Bypass Versus Laparoscopic Gastric Banding.Creative Commons 'BY' version 4.0 license
              • Article
              • Peer Reviewed
              UC Irvine Previously Published Works (2022)

              Background

              Obesity and several obesity-related co-morbidities are risk factors for severe COVID-19 disease. Because bariatric surgery successfully treats obesity-related conditions, we hypothesized that prior bariatric surgery may be associated with less severe COVID-19 disease.

              Objectives

              To examine the association between prior bariatric surgery and outcomes in patients with obesity admitted with COVID-19.

              Setting

              United States METHODS: The Vizient database was used to obtain demographic and outcomes data for adults with obesity admitted with COVID-19 from May 2020 to January 2021. Patients were divided into 2 groups: those with and those without prior bariatric surgery. The primary outcome was in-hospital mortality. Secondary outcomes were mortality by age, sex, race/ethnicity, and co-morbidity; intubation rate; hemodialysis rate; and length of stay. Because the database only provides aggregate data and not patient-level data, multivariate analysis could not be performed.

              Results

              Among the 124,699 patients with obesity admitted with COVID-19, 2,607 had previous bariatric surgery and 122,092 did not. The proportion of patients ≥65 years of age was higher in the non-bariatric surgery group (36.0% versus 27.6%, P < .0001). Compared with patients without prior bariatric surgery, patients with prior bariatric surgery had lower in-hospital mortality (7.8 versus 11.2%, P < .0001) and intubation rates (18.5% versus 23.6%, P = .0009). Hemodialysis rate (7.2% versus 6.9%, P = .5) and length of stay (8.8 versus 9.6 days, P = .8) were similar between groups. Mortality was significantly lower in the bariatric surgery group for patients 18-64 years of age (5.9% versus 7.4%, P = .01) and ≥65 years of age (12.9% versus 17.9%, P = .0006).

              Conclusions

              This retrospective cohort study found that inpatients with obesity and COVID-19 who had prior bariatric surgery had improved outcomes compared with a similar cohort without prior bariatric surgery. Further studies should examine mechanisms for the association between bariatric surgery and less severe COVID-19.
                Cover page: Outcomes of obese patients hospitalized with COVID-19: the impact of prior bariatric surgery
                • Article
                • Peer Reviewed
                UC Irvine Previously Published Works (2011)

                Background

                Obesity is one of the most important modifiable risk factors for the prevention of type 2 diabetes. The aim of this study was to examine the prevalence of diabetes with increasing severity of obesity and the distribution of HbA1c levels in diabetics participating in the latest National Health and Nutrition Examination Survey (NHANES).

                Methods

                Data from a representative sample of adults with diabetes participating in the NHANES between 1999 and 2006 were reviewed. The prevalence of diabetes and levels of fasting glucose, insulin, c-peptide, and HbA1c were examined across different weight classes with normal weight, overweight, and obesity classes 1, 2, and 3 were defined as body mass index (BMI) of <25.0, 25.0-29.9, 30.0-34.9, 35.0-39.9, and equal to 40.0, respectively. The distribution of HbA1c levels among adults with diabetes was also examined.

                Results

                There were 2,894 adults with diabetes (13.6%) among the 21,205 surveyed participants. Among the adults with diabetes, the mean age was 59 years, the mean fasting glucose was 155 ± 2 mg/dl, and the mean HbA1c was 7.2%; 80.3% of diabetics were considered overweight (BMI ≥ 25) and 49.1% of diabetics were considered obese (BMI ≥ 30). The prevalence of adults with diabetes increased with increasing weight classes, from 8% for normal weight individuals to 43% for individuals with obesity class 3; the distribution of HbA1c levels were considered as good (<7.0%) in 60%, fair (7.0-8.0%) in 17%, and poor (>8.0%) in 23%. The mean fasting glucose and HbA1c levels were highest for diabetics with BMI <25.0, suggesting a state of higher severity of disease. Mean insulin and c-peptide levels were highest for diabetics with BMI = 35.0, suggesting a state of insulin resistance.

                Conclusions

                In a nationally representative sample of US adults, the prevalence of diabetes increases with increasing weight classes. Nearly one fourth of adults with diabetes have poor glycemic control and nearly half of adult diabetics are considered obese suggesting that weight loss is an important intervention in an effort to reduce the impact of diabetes on the health care system.
                  Cover page: Relationship Between Obesity and Diabetes in a US Adult Population: Findings from the National Health and Nutrition Examination Survey, 1999–2006Creative Commons 'BY' version 4.0 license
                  • Article
                  • Peer Reviewed
                  UC Irvine Previously Published Works (2023)
                  INTRODUCTION: Reports vary on the impact of obesity on the incidence of lower extremity fractures after a fall. We hypothesized that obese adolescents (OA) presenting after a fall have a higher risk of any and severe lower extremity fractures compared to non-OAs. METHODS: A national database was queried for adolescents (12-17 years old) after a fall. Primary outcome included lower extremity fracture. Adolescents with a body mass index (BMI) ≥ 30 (OA) were compared to adolescents with a BMI < 30 (non-OA). RESULTS: From 20,264 falls, 2523 (12.5%) included OAs. Compared to non-OAs, the rate of any lower extremity fracture was higher for OAs (51.5% vs. 30.7%, p < 0.001). This remained true for lower extremity fractures at all locations (all p < 0.05). After adjusting for sex and age, associated risk for any lower extremity fracture (OR 2.41, CI 2.22-2.63, p < 0.001) and severe lower extremity fracture (OR 1.31, CI 1.15-1.49, p < 0.001) was higher for OAs. This remained true in subset analyses of ground level falls (GLF) and falls from height (FFH) (all p < 0.05). CONCLUSIONS: Obesity significantly impacts adolescents risk of all types of lower extremity fractures after FFH or GLF. Hence, providers should have heightened awareness for possible lower extremity fractures in OAs. LEVEL OF EVIDENCE: IV.
                    Cover page: Obese adolescents have higher risk for severe lower extremity fractures after falling.
                    • Article
                    • Peer Reviewed
                    UC Irvine Previously Published Works (2018)
                    BACKGROUND:Laparoscopic Roux-en-Y gastric bypass (LRYGB) has been performed with successful discharge on postoperative day 1 (POD1). There are limited studies on same-day discharge after LRYGB. The objective of this study was to examine the frequency and outcomes of same-day discharge after LRYGB. STUDY DESIGN:The 2015 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database was analyzed for adult patients who underwent elective LRYGB cases with same-day vs POD1 discharge. Open and revisional cases were excluded. Multivariate analysis was performed to compare risk-adjusted 30-day mortality, overall morbidity, readmission, and reoperation. RESULTS:There were 354 (0.9%) patients who were discharged on the same day as surgery after LRYGB. After exclusion criteria, 319 patients with same-day discharge and 9,402 patients with POD1 discharge were examined. For same-day vs POD1 discharge groups, mean ages were 45.0 and 44.5 years, respectively, and mean BMIs were 47.3 kg/m2 and 45.9 kg/m2, respectively. The unadjusted mortality rate was significantly higher for same-day compared with POD1 discharge (0.94% vs. 0.05%, respectively; p = 0.0017). Compared with POD1 discharge, same-day discharge had higher overall morbidity (3.76% vs 1.54%; adjusted odds ratio [AOR] 2.41; p = 0.0216), but no statistically significant differences for readmissions (3.45% vs. 3.66%; AOR 0.85; p = 0.9999) or reoperations (1.88% vs. 0.89%; AOR 2.33; p = 0.2428). CONCLUSIONS:Same-day discharge after LRYGB is associated with increased morbidity and mortality compared with POD1 discharge. The practice of same-day discharge after LRYGB should be considered experimental until further studies confirm which patient characteristics will ensure safe same-day discharge.
                      Cover page: Same-Day Discharge after Laparoscopic Roux-en-Y Gastric Bypass: An Analysis of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program DatabaseCreative Commons 'BY' version 4.0 license
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