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Open Access Publications from the University of California

Scholarly Works (54 results)

  • Article
Working Papers (2002)
    Cover page: Sowing the Seeds of Conflict: A History of the Senate Confirmation Debates of President Ronald Reagan’s Appointments
    • Book
    • Peer Reviewed
    FlashPoints (2014)
      Cover page: Periodizing Jameson: Dialectics, the University, and the Desire for Narrative
      • Thesis
      • Peer Reviewed
      UC San Diego Electronic Theses and Dissertations (2009)
      This dissertation describes gill specializations related to fast, continuous swimming in tunas, bonitos, and mackerels (family Scombridae), the billfishes (Istiophoridae, Xiphiidae) and the shortfin mako, Isurus oxyrinchus (Lamnidae). These fishes all require gill adaptations for increased gas exchange to meet relatively high aerobic demands and for added rigidity to withstand the forceful branchial flow produced by ram ventilation. Preliminary research for this dissertation, included as an appendix chapter and published as Wegner et al. (2006), examined gill specializations in the striped marlin, Kajikia audax (formerly Tetrapturus audax), and the wahoo, Acanthocybium solandri, and sets the stage for Chapters 1- 4. Chapter 1 documents changes in scombrid and billfish gill morphometrics which augment gill surface area above that of other fish groups and increase branchial resistance to slow and streamline ram-ventilatory flow. Many scombrids and billfishes also have gill fusions which provide support and secure the spatial relationship of filaments and lamellae. Chapter 2 details the structure, function, and distribution of these fusions within different species; they are most complex in large tunas and billfishes, which are obligate ram ventilators, but are absent in mackerels, which utilize active ventilation at slower swimming speeds. Chapter 3 investigates the convergence of mako and tuna gill structure in relation to high aerobic demands and ram ventilation and shows that although makos have relatively larger gill surface areas and shorter diffusion distances than those of other shark species, these features are not as specialized as those of tunas. This work suggests that differences in the gill design of elasmobranchs and teleosts may limit mako gill surface area and ultimately constrain mako aerobic performance in comparison to tunas. Chapter 4 tests this hypothesis with in vivo studies of gill function in makos swimming in a water tunnel. Mako gills are similar to those of tunas in terms of oxygen utilization, the total pressure gradient driving the ventilatory stream, and flow conditions along the respiratory surfaces. However, the interbranchial septum, an intrinsic feature of the shark gill, greatly contributes to mako branchial resistance, and this is compensated by changes to gill dimensions that ultimately limit gill surface area.
        Cover page: Morphology, function, and evolution of the gills of high- performance fishes
        • Article
        • Peer Reviewed
        Research Theses and Dissertations (2009)

        This dissertation describes gill specializations related to fast, continuous swimming in tunas, bonitos, and mackerels (family Scombridae), the billfishes (Istiophoridae, Xiphiidae) and the shortfin mako, Isurus oxyrinchus (Lamnidae). These fishes all require gill adaptations for increased gas exchange to meet relatively high aerobic demands and for added rigidity to withstand the forceful branchial flow produced by ram ventilation. Preliminary research for this dissertation, included as an appendix chapter and published as Wegner et al. (2006), examined gill specializations in the striped marlin, Kajikia audax (formerly Tetrapturus audax ), and the wahoo, Acanthocybium solandri, and sets the stage for Chapters 1-4. Chapter 1 documents changes in scombrid and billfish gill morphometrics which augment gill surface area above that of other fish groups and increase branchial resistance to slow and streamline ram-ventilatory flow. Many scombrids and billfishes also have gill fusions which provide support and secure the spatial relationship of filaments and lamellae. Chapter 2 details the structure, function, and distribution of these fusions within different species; they are most complex in large tunas and billfishes, which are obligate ram ventilators, but are absent in mackerels, which utilize active ventilation at slower swimming speeds. Chapter 3 investigates the convergence of mako and tuna gill structure in relation to high aerobic demands and ram ventilation and shows that although makos have relatively larger gill surface areas and shorter diffusion distances than those of other shark species, these features are not as specialized as those of tunas. This work suggests that differences in the gill design of elasmobranchs and teleosts may limit mako gill surface area and ultimately constrain mako aerobic performance in comparison to tunas. Chapter 4 tests this hypothesis with in vivo studies of gill function in makos swimming in a water tunnel. Mako gills are similar to those of tunas in terms of oxygen utilization, the total pressure gradient driving the ventilatory stream, and flow conditions along the respiratory surfaces. However, the interbranchial septum, an intrinsic feature of the shark gill, greatly contributes to mako branchial resistance, and this is compensated by changes to gill dimensions that ultimately limit gill surface area.

          Cover page: Morphology, Function, and Evolution of the Gills of High-Performance Fishes
          • Article
          • Peer Reviewed
          UC Davis Previously Published Works (2017)

          Study design

          Review of literature.

          Objectives

          This review of literature investigates the application of mesenchymal stem cells (MSCs) in spinal fusion, highlights potential uses in the development of bone grafts, and discusses limitations based on both preclinical and clinical models.

          Methods

          A review of literature was conducted looking at current studies using stem cells for augmentation of spinal fusion in both animal and human models.

          Results

          Eleven preclinical studies were found that used various animal models. Average fusion rates across studies were 59.8% for autograft and 73.7% for stem cell-based grafts. Outcomes included manual palpation and stressing of the fusion, radiography, micro-computed tomography (μCT), and histological analysis. Fifteen clinical studies, 7 prospective and 8 retrospective, were found. Fusion rates ranged from 60% to 100%, averaging 87.1% in experimental groups and 87.2% in autograft control groups.

          Conclusions

          It appears that there is minimal clinical difference between commercially available stem cells and bone marrow aspirates indicating that MSCs may be a good choice in a patient with poor marrow quality. Overcoming morbidity and limitations of autograft for spinal fusion, remains a significant problem for spinal surgeons and further studies are needed to determine the efficacy of stem cells in augmenting spinal fusion.
            Cover page: Stem Cells in Spinal Fusion.
            • Article
            • Peer Reviewed
            UC Irvine Previously Published Works (2017)

            Objective

            Understanding individual differences in the psychobiology of the stress response is critical to grasping how psychosocial factors contribute to racial and ethnic health disparities. However, the ways in which environmentally sensitive biological systems coordinate in response to acute stress is not well understood. We used a social-evaluative stress task to investigate coordination among the autonomic nervous system, hypothalamic-pituitary-adrenal axis, and immune/inflammatory system in a community sample of 85 healthy African American men and women.

            Methods

            Six saliva samples, 2 at each of baseline, event, and recovery phases of the stressor task, were assayed for cortisol, dehydroepiandrosterone-sulfate, salivary alpha-amylase, and salivary C-reactive protein. Individual differences in perceived discrimination and racial identity were also measured.

            Results

            Factor analysis demonstrated that stress systems were largely dissociated before stressor exposure but became aligned during event and recovery phases into functional biological stress responses (factor loadings ≥ .58). Coordinated responses were related to interactions of perceived discrimination and racial identity: when racial identity was strong, highly perceived discrimination was associated with low hypothalamic-pituitary-adrenal axis activity at baseline (B's = .68-.72, p < .001), low stress mobilization during the task (B's = .46-.62, p < .049), and a robust inflammatory response (salivary C-reactive protein) during recovery (B's = .72-.94, p < .002).

            Conclusion

            Culturally relevant social perceptions may be linked to a specific pattern of changing alignment in biological components of the stress response. Better understanding these links may significantly advance understanding of stress-related illnesses and disparities.
              Cover page: Perceived Discrimination, Racial Identity, and Multisystem Stress Response to Social Evaluative Threat Among African American Men and WomenCreative Commons 'BY' version 4.0 license
              • Article
              • Peer Reviewed
              UC San Diego Previously Published Works (2019)
              Aquatic organisms have specialized cells called ionocytes that regulate the ionic composition, osmolarity, and acid/base status of internal fluids. In small aquatic organisms such as fishes in their early life stages, ionocytes are typically found on the cutaneous surface and their abundance can change to help cope with various metabolic and environmental factors. Ionocytes profusely express ATPase enzymes, most notably Na+/K+ ATPase, which can be identified by immunohistochemistry. However, quantification of cutaneous ionocytes is not trivial due to the limited camera's focal plane and the microscope's field-of-view. This protocol describes a technique to consistently and reliably identify, image, and measure the relative surface area covered by cutaneous ionocytes through software-mediated focus-stacking and photo-stitching-thereby allowing the quantification of cutaneous ionocyte area as a proxy for ion transporting capacity across the skin. Because ionocytes are essential for regulating ionic composition, osmolarity, and acid/base status of internal fluids, this technique is useful for studying physiological mechanisms used by fish larvae and other small aquatic organisms during development and in response to environmental stress.
                • Article
                • Peer Reviewed
                UC San Diego Previously Published Works (2023)
                Below the surface layers of the ocean, there are ecosystems full of undiscovered life. Scientists love to ask questions like, “Who is there?” and “What are they doing?” An important question scientists are beginning to ask is, “How will these living things react to warmer waters, loss of oxygen, or pollution?” To answer these questions, scientists build equipment to observe life in the deep sea. We built an ocean lander named BEEBE, with a camera, sensors, and waterproof casing. BEEBE helped us study deep-sea ecosystems near the coast of California and learn about the animals that live there. We can use what we learned to recognize vulnerable communities and the threats some ocean animals face. An ocean lander like BEEBE can be a great tool to learn more about coastal, deep-sea ecosystems around the world!
                  Cover page: Spies in the Deep: Ocean Landers Explore the Deep Sea
                  • Article
                  Recent Work (1995)

                  We studied the effect of traffic intensity on local abundance of anurans. We counted dead and live frogs and toads per km and estimated frog and toad local abundances using breeding chorus intensities on similar roads through similar habitats, but with different levels of traffic intensity. After correcting for effects of date, local habitat, time, and region, our analyses demonstrated that (1) the number of dead and live frogs and toads per km decreased with increasing traffic intensity; (2) the proportion of frogs and toads dead increased with increasing traffic intensity; and (3) the frog and toad density, as measured by the chorus intensity, decreased with increasing traffic intensity. Taken together, our results indicate that traffic mortality has a significant negative effect on the local density of anurans. Our results suggest that recent increases in traffic volumes worldwide are probably contributing to declines in amphibian populations, particularly in populated areas.

                    Cover page: Effect of road traffic on amphibian density
                    • Article
                    • Peer Reviewed
                    UC San Francisco Previously Published Works (2015)
                    The STriatal-Enriched protein tyrosine Phosphatase (STEP) is a brain-specific phosphatase whose dysregulation in expression and/or activity is associated with several neuropsychiatric disorders. We recently showed that long-term excessive consumption of ethanol induces a sustained inhibition of STEP activity in the dorsomedial striatum (DMS) of mice. We further showed that down-regulation of STEP expression in the DMS, and not in the adjacent dorsolateral striatum, increases ethanol intake, suggesting that the inactivation of STEP in the DMS contributes to the development of ethanol drinking behaviors. Here, we compared the consequence of global deletion of the STEP gene on voluntary ethanol intake to the consumption of an appetitive rewarding substance (saccharin) or an aversive solution (quinine or denatonium). Whereas saccharin intake was similar in STEP knockout (KO) and wild type (WT) littermate mice, the consumption of ethanol as well as quinine and denatonium was increased in STEP KO mice. These results suggested that the aversive taste of these substances was masked upon deletion of the STEP gene. We therefore hypothesized that STEP contributes to the physiological avoidance towards aversive stimuli. To further test this hypothesis, we measured the responses of STEP KO and WT mice to lithium-induced conditioned place aversion (CPA) and found that whereas WT mice developed lithium place aversion, STEP KO mice did not. In contrast, conditioned place preference (CPP) to ethanol was similar in both genotypes. Together, our results indicate that STEP contributes, at least in part, to the protection against the ingestion of aversive agents.
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