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Open Access Publications from the University of California

Scholarly Works (32 results)

  • Article
Cultivating A Movement (2010)

Amy Katzenstein-Escobar was the first pilot teacher for the Life Lab Science Program. She was born in 1956 in New Jersey, and grew up in Southern California. She came to UC Santa Cruz in the mid-1970s and entered the community studies major. She received a Ford Foundation education project grant to teach migrant children from Watsonville, became a teacher, and then began teaching at Salsipuedes School, where she participated in a pilot project for Life Lab in 1980. She discusses her Life Lab work in this oral history, conducted by Ellen Farmer on July 27, 2007, in an office on the UC Santa Cruz campus.

  • 2 supplemental audio files
Cover page: Amy Katzenstein-Escobar: Life Lab Teacher
  • Thesis
  • Peer Reviewed
UCLA Electronic Theses and Dissertations (2012)

Navigation, localization, and targeting while completely submerged in the ocean are all extremely difficult due to the lack of a proficient sensor. The highly conductive nature of salt-water results in severe radio-wave attenuation precluding the use of RADAR. Naturally occurring noise sources, high energy costs, long-wavelengths, and surface turbidity restrict the use of SONAR imaging to low resolutions, depths, and far fields. The ocean's dark, turbulent, and silty disposition impedes optical imaging.

Nature knows another better way. Apteronotus Albifrons is a nocturnal oceanic fish that cannot rely upon optical notions of vision to navigate, hunt, or avoid predators. Instead, it relies upon an electroreceptive capability achieved through a dense grid of electric field (Voltage) sensors arrayed along both sides of the body and concentrated around the head. It emits an electric field into the water and senses the self-induced forces down its sides. Objects in the vicinity that differ in conductivity from the background ocean environment disturb the field, redistribute the current, and hence the spatial distribution of voltages measured by the fish.

This dissertation chronicles the effort to produce an engineered sensor which mirrors the biological phenomenon of electroreception and demonstrate its ability to "visualize" targets with different conductivities from the background ocean environment at very high resolution by detecting perturbations in a quasi-static electric field (electrostatics). This culminates in the first Biomimetic Electrostatic Images (BEI) and demonstrates the potential of the technology to provide significant advances in underwater scientific enterprises, military applications, as well as in medicine.

    Cover page: Biomimetic Electrostatics for Submerged Oceanic Sensing, Communication, and Coordination
    • Article
    UCLA Criminal Justice Law Review, Volume 4, Issue 1 (2020)
      Cover page: Alabama is US: Concealed Fees in Jails and Prisons
      • Article
      • Peer Reviewed
      UC Davis Previously Published Works (1997)
      Naturally occurring human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) variability has implications for the success of antiretroviral therapy. We determined the sequence of the polymerase-coding region of RT from virus isolates from 12 Zimbabwean individuals recently infected with HIV-1. The 12 RT sequences differed from the consensus B RT sequence at 10.5% of nucleotides and 5.8% of amino acids. Susceptibility testing of five isolates to zidovudine, didanosine, lamivudine, and nevirapine demonstrated susceptibilities similar to those of wild-type subtype B isolates. Phylogenetic analysis of 40 HIV-1 RT sequences, including the 12 Zimbabwean subtype C sequences, 11 subtype B sequences, and the 17 remaining published non-subtype B sequences showed sufficient intrasubtype RT sequence variation to differentiate subtype A, B, C, and D isolates. Five recently reported subtype C RT sequences from India grouped with the Zimbabwean subtype C sequences but had significantly less intraisolate sequence variation. Both intra- and intersubtype RT comparisons were notable for extraordinarily high ratios of synonymous to nonsynonymous differences. Although substitutions in the HIV-1 RT gene are limited by functional constraints, variation between RT sequences demonstrates phylogenetic relationships that parallel env and gag gene variation.
        Cover page: Sequence and drug susceptibility of subtype C reverse transcriptase from human immunodeficiency virus type 1 seroconverters in Zimbabwe.
        • Article
        • Peer Reviewed
        UC San Francisco Previously Published Works (2020)

        Background

        Women in low- and middle-income countries are at the highest risk of cervical cancer yet have limited access to and participation in cervical cancer screening programs. Integrating self-collected, community-based screening offers a potential primary screening method in areas of limited resources. In this paper, we present a study evaluating knowledge, attitudes, and practices of cervical cancer and Human Papilloma Virus (HPV) in rural Zimbabwe.

        Methods

        We performed a community-based cross-sectional knowledge, attitudes and practices of HPV and cervical cancer study in rural Zimbabwe from January 2017-May 2017. Women were selected for the study via random number generation from complete lists of inhabitants in the study area if they satisfied the inclusion criteria (≥30-years-old, ≤65-years-old, not pregnant, intact uterus). If selected, they participated in a 19-question structured knowledge, attitudes and practices survey. The questionnaire included questions on demographics, education, knowledge of HPV, cervical cancer, and risk factors. Chi-squared tests were evaluated comparing knowledge, attitudes and practices relating to HPV and cervical cancer screening with actual infection with HPV. Women were also offered a voluntary HIV and self-collected HPV screening.

        Results

        Six hundred seventy-nine women were included in the knowledge, attitudes and practices survey. Most women (81%) had heard of cervical cancer while the majority had not heard of HPV (12%). The number of women that had been screened previously for cervical cancer was low (5%). There were no significant differences between and within groups regarding knowledge of cervical cancer and actual overall infection with HR-HPV, HPV 16, and HPV 18/45 test results.

        Conclusions

        Most women in rural Zimbabwe have heard of cervical cancer, but the number that had been screened was low. Extending existing outreach services to include cervical cancer screening, potentially including HPV screening, should include cervical cancer/HPV education and screening triage. This approach would serve to bridge the gap between knowledge and screening availability to address some of the barriers to cervical cancer care still affecting women in many regions of the world.
          Cover page: Knowledge, attitudes, and practices of cervical Cancer screening among HIV-positive and HIV-negative women participating in human papillomavirus screening in rural ZimbabweCreative Commons 'BY' version 4.0 license
          • Article
          • Peer Reviewed
          UC San Francisco Previously Published Works (2019)

          Background

          In low- and middle-income countries (LMIC), women have limited access to and uptake of cervical cancer screening. Delayed diagnosis leads to poorer outcomes and early mortality, and continues to impede cancer control disproportionately in LMIC. Integrating self-collected, community-based screening for High Risk-Human Papilloma Virus (HR-HPV) into existent HIV programs is a potential screening method to identify women at high risk for developing high-risk cervical lesions.

          Methods

          We implemented community-based cross-sectional study on self-collection HR-HPV screening in conjunction with existing community outreach models for the distribution of antiretroviral therapy (ART) and the World Health Organization Expanded Program on Immunization (EPI) outreach in villages in rural Zimbabwe from January 2017 through May 2017.

          Results

          Overall, there was an 82% response rate: 70% of respondents participated in self-collection and 12% were ineligible for the study (inclusion criteria: age 30-65, not pregnant, with an intact uterus). Women recruited in the first 2-3 months of the study had more opportunities to participate and therefore significantly higher participation: 81% participation (additional 11% ineligible), while those with fewer opportunities also had lower participation: 63% (additional 13% ineligible) (p < 0.001). Some village outreach centers (N = 5/12) had greater than 89% participation.

          Conclusions

          Integration of HR-HPV screening into existing community outreach models for HIV and immunizations could facilitate population-based screening to scale cancer control and prevention programs in sub-Saharan Africa. Community/village health workers (CHW/VHW) and village outreach programs offer a potential option for cervical cancer screening programs to move towards improving access of sexual and reproductive health resources for women at highest risk.
            Cover page: Community-based self-collected human papillomavirus screening in rural ZimbabweCreative Commons 'BY' version 4.0 license
            • Article
            • Peer Reviewed
            UC Davis Previously Published Works (2023)
            Liver tumors account for approximately 1%-2% of all pediatric malignancies, with the two most common tumors being hepatoblastoma (HB) and hepatocellular carcinoma (HCC). Previous Childrens Oncology Group studies have meaningfully contributed to the current understanding of disease pathophysiology and treatment, laying groundwork for the ongoing prospective international study of both HB and HCC. Future work is focused on elucidating the biologic underpinnings of disease to support an evolution in risk categorization, advancements in the multidimensional care required to treat these patients, and the discovery of novel therapies.
              Cover page: Childrens Oncology Groups 2023 blueprint for research: Liver tumors.
              • Article
              • Peer Reviewed
              UC San Francisco Previously Published Works (2021)
              Objective methods of measuring antiretroviral adherence are limited. We assessed the relationship between tenofovir disoproxil fumarate (TDF) hair concentrations, self-reported adherence, and virological outcomes in HIV-infected adolescents in Harare, Zimbabwe. HIV-infected adolescents on atazanavir/ritonavir-based second-line treatment for >6 months with viral load (VL) ≥1,000 copies/mL were randomized to either modified directly administered antiretroviral therapy (mDAART) or standard of care. Hair and VL samples were collected at baseline and after 90 days. Treatment outcome was defined as TDF concentrations in hair. Virological suppression was defined as VL <1,000 copies/mL. Thirty-four adolescents had TDF concentrations measured at baseline and follow-up. Mean (median); range age was 16 (16); 13-18 years and 53% were females. Nineteen (56%) were randomized to mDAART. Mean (SD); range TDF concentrations were 0.03 (0.04); 0-0.17 ng/mg hair and 0.06 (0.06); 0-0.3 ng/mg hair at baseline and follow-up, respectively. Higher TDF concentrations were associated with decreased VL [regression coefficient (RC) 0.8; 95% confidence interval (CI) 0.7-1.0; p = .008] and mDAART (RC 0.5; 95% CI 0.3-1.0; p = .04), but were not associated with self-reported adherence and virological suppression (VL <1,000 copies/mL). Higher TDF hair concentrations were observed with virological decrease and an adherence intervention. Hair antiretroviral concentrations could be useful in triggering adherence interventions among adolescents with second-line virological failure.
                Cover page: Short Communication: Higher Tenofovir Concentrations in Hair Are Associated with Decreases in Viral Load and Not Self-Reported Adherence in HIV-Infected Adolescents with Second-Line Virological Treatment Failure
                • Article
                • Peer Reviewed
                UC San Francisco Previously Published Works (2017)

                Background

                Adequate antiretroviral exposure is crucial to virological suppression. We assessed the relationship between atazanavir hair levels with self-reported adherence, virological outcomes, and the effect of a home-based adherence intervention in HIV-infected adolescents failing second-line antiretroviral treatment in Zimbabwe.

                Methods

                HIV-infected adolescents on atazanavir/ritonavir-based second-line treatment for ≥6 months with viral load (VL) >1000 copies/mL were randomized to either standard care (control) or standard care plus modified directly administered antiretroviral therapy (intervention). Questionnaires were administered; VL and hair samples were collected at baseline and after 90 days in each group. Viral suppression was defined as <1000 copies/mL after follow-up.

                Results

                Fifty adolescents (10-18 years) were enrolled; 23 (46%) were randomized to intervention and 27 (54%) to control. Atazanavir hair concentration <2.35 ng/mg (lower interquartile range for those with virological suppression) defined a cutoff below which most participants experienced virological failure. Male sex (P = 0.03), virological suppression at follow-up (P = 0.013), greater reduction in VL (P = 0.006), and change in average self-reported adherence over the previous month (P = 0.031) were associated with adequate (>2.35 ng/mg) hair concentrations. Participants with virological failure were more likely to have suboptimal atazanavir hair concentrations (RR = 7.2, 95% CI: 1 to 51, P = 0.049). There were no differences in atazanavir hair concentration between the arms after follow-up.

                Conclusions

                A threshold of atazanavir concentrations in hair (2.35 ng/mg), above which virological suppression was likely, was defined for adolescents failing second-line atazanavir/ritonavir-based ART in Zimbabwe. Male sex and better self-reported adherence were associated with adequate atazanavir hair concentrations. Antiretroviral hair concentrations may serve as a useful clinical tool among adolescents.
                  Cover page: Defining a Cutoff for Atazanavir in Hair Samples Associated With Virological Failure Among Adolescents Failing Second-Line Antiretroviral Treatment
                  • Article
                  • Peer Reviewed
                  UC San Francisco Previously Published Works (2019)

                  Objectives

                  High-risk human papilloma viruses (hrHPV) are the causative agents of cervical cancer, the leading cause of cancer deaths among Zimbabwean women. The objective of this study was to describe the hrHPV types found in Zimbabwe for consideration in cervical cancer screening and vaccination efforts.

                  Design and methods

                  To determine hrHPV prevalence and type distribution in Zimbabwe we implemented a community-based cross-sectional study of self-collected cervicovaginal samples with hrHPV screening using near-point-of-care Cepheid GeneXpert HPV.

                  Results

                  The hrHPV prevalence was 17% (112/643); 33% (41/123) vs. 14% (71/520) among HIV-1-positive and -negative participants, respectively (p=2.3E-07). Typing via Xpert HPV showed very good overall agreement (77.2%, kappa=0.698) with the Seegene Anyplex II HPV HR Detection kit. The most common types were HPV16, HPV18, HPV35, HPV52, HPV58, HPV68, HPV18, and HPV51, each of which appeared in 14-20% of infections. 37% (28/76) of women with positive cytology results (ASCUS+) had a type not included in the basic vaccine and 25% (19/76) had a type not currently in the nine-valent vaccine.

                  Conclusions

                  hrHPV type distribution includes less common high-risk types in rural Zimbabwe. The distribution and carcinogenicity of hrHPV type distribution should be considered during screening assay design, program development, as well as vaccine distribution and design.
                    Cover page: hrHPV prevalence and type distribution in rural Zimbabwe: A community-based self-collection study using near-point-of-care GeneXpert HPV testingCreative Commons 'BY' version 4.0 license
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