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Open Access Publications from the University of California

Recent Work

The Research Grants Program Office (RGPO) oversees a broad grantmaking portfolio of nearly $65 million a year to support research that is critical to California, the nation and the world. RGPO programs enhance UC’s research capacity and excellence, which helps attract top faculty, graduate students, government funding and companies to our state. These grants also enable researchers and community agencies to collaborate and solve the most pressing problems in the state. RGPO also provides grants for training undergraduates, graduate and postdoctoral researchers, whose work will benefit California communities. 

Cover page of The polymeric conformational effect on capacitive deionization performance of graphene oxide/polypyrrole composite electrode

The polymeric conformational effect on capacitive deionization performance of graphene oxide/polypyrrole composite electrode

(2020)

© 2020 Elsevier B.V. Exploitation of novel faradic materials is an alternative implementation for solving the problem of poor specific electrosorption capacity that conventional carbon materials are encountered in capacitive deionization. Particularly, composite electrode is just a suitable choice because of its potentially high ion-storage ability. Herein, a cyclic voltammetric treatment method with different low limit of potential window was used to manipulate the polymeric conformation and doping level of graphene oxide/polypyrrole (GO/PPy) composite electrode. Based on it, the effect of polymeric structure on the electrosorption performance was systematically studied. When the low limit of potential window is shifted negatively enough, the irreversible polymeric conformational shrinks of GO/PPy are promoted, which not only hinders the insertion process of ions, but also decreases the doping level of polymer due to the intensive interchain-action produced by more entangled polymeric chain. Thus, the number of intercalated ions should decrease, which is expressed by electrochemical impedance spectroscopy (EIS) results and is proportional to the electrosorption capacity of GO/PPy composite electrode in membrane capacitive deionization (MCDI) process. Our work suggests that the less packing density, higher doping level and more charge delocalization on PPy backbone in electrode are beneficial to enhance its capacitive deionization performance.

Occupational livestock or animal dust exposure and offspring cancer risk in Denmark, 1968-2016.

(2020)

OBJECTIVE:To examine associations with occupational livestock or other animal dust exposure and offspring cancer risk. METHODS:In this population-based case-control study of Danish children aged < 17 years old, 5078 childhood cancer cases diagnosed 1968-2016 were matched to cancer-free controls by birth year and sex (n = 123,228). Occupational livestock or animal dust exposure was identified using a job-exposure matrix. We employed multivariable conditional logistic regression models to estimate associations with offspring cancer for births 1968-2016 and 1989-2016, with the latter timeframe reflecting a period of presumed higher exposure due to changes in Danish farming practices. Sensitivity analyses considered place of birth (urban areas vs. rural areas and small towns). RESULTS:For births 1968-2016, paternal exposure from offspring birth to cancer diagnosis was associated with central nervous system tumors (adjusted odds ratio [OR] = 1.30, 95% confidence interval [CI] 1.04-1.63) and germ cell tumors (OR = 1.82, 95% CI 1.05-3.27), while maternal pregnancy exposure was associated with astrocytoma (OR = 1.89, 95% CI 1.00-3.57). For births 1989-2016, paternal exposure from offspring birth to cancer diagnosis was negatively associated with acute lymphoid leukemia (OR = 0.58, 95% CI 0.33-1.00). For births in rural areas only, maternal exposure from offspring birth to cancer diagnosis was positively associated with acute myeloid leukemia (OR = 2.16, 95% CI 1.09-4.29). CONCLUSIONS:This study suggests that paternal occupational animal exposure is associated with offspring germ cell tumors, and maternal pregnancy exposure with astrocytomas. Our results are mixed with respect to leukemia subtypes.

Cumulative Burden of Depression and Neurocognitive Decline Among Persons With HIV: A Longitudinal Study.

(2020)

BACKGROUND:Higher cumulative burden of depression among people with HIV (PWH) is associated with poorer health outcomes; however, longitudinal relationships with neurocognition are unclear. This study examined hypotheses that among PWH, (1) higher cumulative burden of depression would relate to steeper declines in neurocognition, and (2) visit-to-visit depression severity would relate to fluctuations in neurocognition within persons. SETTING:Data were collected at a university-based research center from 2002 to 2016. METHODS:Participants included 448 PWH followed longitudinally. All participants had >1 visit (M = 4.97; SD = 3.53) capturing depression severity (Beck Depression Inventory-II) and neurocognition (comprehensive test battery). Cumulative burden of depression was calculated using an established method that derives weighted depression severity scores by time between visits and total time on study. Participants were categorized into low (67%), medium (15%), and high (18%) depression burden. Multilevel modeling examined between- and within-person associations between cumulative depression burden and neurocognition over time. RESULTS:The high depression burden group demonstrated steeper global neurocognitive decline compared with the low depression burden group (b = -0.100, P = 0.001); this was driven by declines in executive functioning, delayed recall, and verbal fluency. Within-person results showed that compared with visits when participants reported minimal depressive symptoms, their neurocognition was worse when they reported mild (b = -0.12, P = 0.04) or moderate-to-severe (b = -0.15, P = 0.03) symptoms; this was driven by worsened motor skills and processing speed. CONCLUSIONS:High cumulative burden of depression is associated with worsening neurocognition among PWH, which may relate to poor HIV-related treatment outcomes. Intensive interventions among severely depressed PWH may benefit physical, mental, and cognitive health.

#HIV: Alignment of HIV-Related Visual Content on Instagram with Public Health Priorities in the US.

(2020)

Instagram, with more than 1 billion monthly users, is the go-to social media platform to chronicle one's life via images, but how are people using the platform to present visual content about HIV? We analyzed public Instagram posts containing the hashtag "#HIV" (because they are self-tagged as related to HIV) between January 2017 and July 2018. We described the prevalence of co-occurring hashtags and explored thematic concepts in the images using automated image recognition and topic modeling. Twenty-eight percent of all #HIV posts included hashtags focused on awareness, followed by LGBTQ (24.5%) and living with HIV (17.9%). However, specific strategies were rarely cited, including testing (10.8%), treatment (10.3%), PrEP (6.2%) and condoms (4.1%). Image analyses revealed 44.5% of posts included infographics followed by people (21.3%) thereby humanizing HIV and stigmatized populations and promoting community mobilization. Novel content such as the handwriting image-theme (3.8%) where posters shared their HIV test results appeared. We discuss how this visual content aligns with public health priorities to reduce HIV in the US and the novel, organic messages that public health could help amplify.

Cover page of Associations Between Body Weight, Hippocampal Volume, and Tissue Signal Intensity in 12- to 18-Year-Olds.

Associations Between Body Weight, Hippocampal Volume, and Tissue Signal Intensity in 12- to 18-Year-Olds.

(2020)

OBJECTIVE:The hippocampus is a key structure in feeding behaviors and weight regulation. Obesity may lead to disruptions in hippocampal structure. In animals, obesity-related factors (e.g., high-fat/sugar foods) are associated with hippocampal insult (e.g., alterations in the blood brain barrier). In humans, individuals with obesity, relative to healthy weight, have smaller hippocampal volumes. Few studies have examined the association between body weight and the hippocampus during adolescence, a critical brain development period. This study examined hippocampal volume and tissue signal intensity in adolescents across the weight spectrum. METHODS:Structural magnetic resonance imaging and anthropomorphic data were available for 102 12- to 18-year-old adolescents (53% female; 15.07 [SD 1.84] years; standardized BMI [BMIz] scores using the Centers for Disease Control and Prevention growth charts: 0.54 [SD 1.17]) from the Pediatric Imaging, Neurocognition, and Genetics database. Linear regression models controlling for age, sex, genetic ancestry, scanner, and household income examined the relationship between BMIz, hippocampal volume, and T2-weighted hippocampal signal intensity. RESULTS:BMIz was negatively associated with T2-weighted hippocampal signal intensity in the left (t = -3.05; P = 0.003; r = -0.21) and right (t = -2.50; P = 0.01; r = -0.36) hippocampi. BMIz was not significantly associated with hippocampal volume. CONCLUSIONS:BMIz is associated with hippocampal tissue characteristics during adolescence, which could impact later brain development.

Cover page of Colloid transport through soil and other porous media under transient flow conditions—A review

Colloid transport through soil and other porous media under transient flow conditions—A review

(2020)

© 2020 Wiley Periodicals, Inc. Understanding colloid transport in porous media under transient-flow conditions is crucial in understanding contaminant transport in soil or the vadose zone where flow conditions vary constantly. In this article, we provide a review of experimental studies, numerical approaches, and new technologies available to determine the transport of colloids in transient flow. Experiments indicate that soil structure and preferential flow are primary factors. In undisturbed soils with preferential flow pathways, macropores serve as main conduits for colloid transport. In homogeneously packed soil, the soil matrix often serves as filter. At the macroscale, transient flow facilitates colloid transport by frequently disturbing the force balance that retains colloids in the soil as indicated by the offset between colloid breakthrough peaks and discharge peaks. At the pore-scale and under saturated condition, straining, and attachment at solid–water interfaces are the main mechanisms for colloid retention. Variably saturated conditions add more complexity, such as immobile water zones, film straining, attachment to air–water interfaces, and air–water–solid contact lines. Filter ripening, size exclusion, ionic strength, and hydrophobicity are identified as the most influential factors. Our review indicates that microscale and continuum-scale models for colloid transport under transient-flow conditions are rare, compared to the numerous steady-state models. The few transient flow models that do exist are highly parameterized and suffer from a lack of a priori information of required pore-scale parameters. However, new techniques are becoming available to measure colloid transport in real-time and in a nondestructive way that might help to better understand transient flow colloid transport. This article is categorized under: Science of Water > Hydrological Processes Science of Water > Water Quality.