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Open Access Publications from the University of California

Scholarly Works (24 results)

  • Thesis
  • Peer Reviewed
UCLA Electronic Theses and Dissertations (2012)

The dissertation is a two-paper investigation of observed naturalistic marital support behavior in a sample of 30 dual-earner middle-class couples with school-aged children who were videotaped in their homes over 4 days (two weekdays, two weekend days). Couples also self-reported on marital satisfaction, job stress, and emotional distress, as well as provided salivary cortisol samples that permitted analysis of diurnal cortisol slopes. Study 1 entails the conceptualization, development, and implementation of a novel observational coding system for naturalistic marital support behavior that provides a comprehensive descriptive analysis of couple support interactions as they unfold in everyday contexts. Analyses indicate that support interactions were relatively rare, predominantly brief (< 30 seconds long), more often solicited than offered, mostly instrumental compared to emotional in content, and overwhelmingly positive versus negative in emotional quality. In addition, patterns were examined among the different support variables; in particular, findings counter the Support Gap Hypothesis and suggest that wives receive more support than husbands, due specifically to wives soliciting more support. Study 2 examines the predictors and outcomes of couple support behavior using the self-reported individual variables and diurnal cortisol slopes. Findings support the notion that emotional distress and job stress predict the support behavior of both spouses. Interesting sex differences emerged, whereby wives' depressive symptoms, wives' job stress, and husbands' neuroticism appeared to have the strongest influence on supportive behavior. However, analyses indicate little evidence for couple support behavior as a predictor of marital satisfaction and diurnal cortisol slopes. The dissertation provides first insights into couple support processes as they spontaneously unfold in naturalistic settings, highlighting the utility of naturalistic observation to shed light on real-life social behavior and its links with health and well-being.

    Cover page: Marital Support, Well-Being, and Health in Everyday Life
    • Article
    • Peer Reviewed
    LBL Publications (2019)
    Abstract: The synthesis of conjugated polymers with ionic substituents directly bound to their main chain repeat units is a strategy for generating strongly electron‐accepting conjugated polyelectrolytes, as demonstrated through the synthesis of a series of ionic azaquinodimethane (iAQM) compounds. The introduction of cationic substituents onto the quinoidal para‐azaquinodimethane (AQM) core gives rise to a strongly electron‐accepting building block, which can be employed in the synthesis of ionic small molecules and conjugated polyelectrolytes (CPEs). Electrochemical measurements alongside theoretical calculations indicate notably low‐lying LUMO values for the iAQMs. The optical band gaps measured for these compounds are highly tunable based on structure, ranging from 2.30 eV in small molecules down to 1.22 eV in polymers. The iAQM small molecules and CPEs showcase the band gap reduction effects of combining the donor‐acceptor strategy with the bond‐length alternation reduction strategy. As a demonstration of their utility, the iAQM CPEs so generated were used as active agents in photothermal therapy.
      Cover page: Electronic Tuning of Mixed Quinoidal‐Aromatic Conjugated Polyelectrolytes: Direct Ionic Substitution on Polymer Main‐Chains
      • Article
      • Peer Reviewed
      LBL Publications (2019)
      The synthesis of conjugated polymers with ionic substituents directly bound to their main chain repeat units is a strategy for generating strongly electron-accepting conjugated polyelectrolytes, as demonstrated through the synthesis of a series of ionic azaquinodimethane (iAQM) compounds. The introduction of cationic substituents onto the quinoidal para-azaquinodimethane (AQM) core gives rise to a strongly electron-accepting building block, which can be employed in the synthesis of ionic small molecules and conjugated polyelectrolytes (CPEs). Electrochemical measurements alongside theoretical calculations indicate notably low-lying LUMO values for the iAQMs. The optical band gaps measured for these compounds are highly tunable based on structure, ranging from 2.30 eV in small molecules down to 1.22 eV in polymers. The iAQM small molecules and CPEs showcase the band gap reduction effects of combining the donor-acceptor strategy with the bond-length alternation reduction strategy. As a demonstration of their utility, the iAQM CPEs so generated were used as active agents in photothermal therapy.
        Cover page: Electronic Tuning of Mixed Quinoidal‐Aromatic Conjugated Polyelectrolytes: Direct Ionic Substitution on Polymer Main‐Chains
        • Article
        • Peer Reviewed
        The Proceedings of the International Plant Nutrition Colloquium XVI (2009)

        In order to increase grain yield of rice, a series of field experiments were conducted using cultivars, Shendao 3 and Shendao 9, with semi-erect panicles treated with seeding rate, transplanting density and application levels of nitrogen (N), phosphorus (P), and potassium (K). The results indicated that grain yield of Shendao 3, or Shendao 9, was affected by the treatment factors. For the two cultivars, high yield could be achieved when N, P and K were applied and plant densities were performed with the amounts corresponding to the level codes 1, 0, -2, 0 and 0. Conversely, deficiency or over application of N, P and K, or plant density, could decrease the grain yield. Increasing application level of the fertilizers from very low (code -2) to very high (code 2), agronomic efficiency (AE) of N, or P, decreased substantially.

          Cover page: Effect of N, P, K and Plant Density on Grain Yield of Rice Cultivars with Semi-erect Panicles
          • Article
          • Peer Reviewed
            Cover page: Hashimoto’s Thyroiditis in children and adolescents: at presentation and during long-term follow up
            • Article
            • Peer Reviewed
            LBL Publications (2023)
            The mid-wave infrared (MWIR), ranging from 2 to 5 micrometers, is of substantial interest for chemical sensing, imaging, and spectroscopy. Black phosphorus (bP)-based MWIR light emitters and detectors have been shown to outperform the state-of-the-art for commercial devices due to the low Auger recombination coefficient of bP. However, the scalability of these devices remains a challenge. Here, we report a bP ink formula that preserves the exceptional MWIR optoelectronic properties of bP to deposit centimeter-scale, uniform, and pinhole free films with a photoluminescence quantum yield higher than competing III-V and II-VI semiconductors with similar bandgaps at high excitation regime. As a proof of concept, we use bP ink as a phosphor on a red commercial light-emitting diode to demonstrate bright MWIR light emission. We also show that these films can be integrated into heterostructure device architectures with electron and hole selective contacts for direct-injected light emission and detection in MWIR.
              Cover page: Large-scale efficient mid-wave infrared optoelectronics based on black phosphorus ink.
              • Article
              • Peer Reviewed
              UC Berkeley Previously Published Works (2024)
              Black phosphorus (bP) is a promising material for mid-infrared (mid-IR) optoelectronic applications, exhibiting high performance light emission and detection. Alloying bP with arsenic extends its operation toward longer wavelengths from 3.7 μm (bP) to 5 μm (bP3As7), which is of great practical interest. Quantitative optical characterizations are performed to establish black phosphorus-arsenic (bPAs) alloys optoelectronic quality. Anisotropic optical constants (refractive index, extinction coefficient, and absorption coefficient) of bPAs alloys from near-infrared to mid-IR (0.2-0.9 eV) are extracted with reflection measurements, which helps optical device design. Quantitative photoluminescence (PL) of bPAs alloys with different As concentrations are measured from room temperature to 77 K. PL quantum yield measurements reveal a 2 orders of magnitude decrease in radiative efficiency with increasing As concentration. An optical cavity is designed for bP3As7, which allows for up to an order of magnitude enhancement in the quantum yield due to the Purcell effect. Our comprehensive optical characterization provides the foundation for high performance mid-IR optical device design using bPAs alloys.
                Cover page: Quantitative Mid-infrared Photoluminescence Characterization of Black Phosphorus–Arsenic Alloys
                • Article
                • Peer Reviewed
                UC Irvine Previously Published Works (2009)
                A novel noncontact indentation system with the combination of an air jet and optical coherence tomography (OCT) was presented in this paper for the quantitative measurement of the mechanical properties of soft tissues. The key idea of this method is to use a pressure-controlled air jet as an indenter to compress the soft tissue in a noncontact way and utilize the OCT signals to extract the deformation induced. This indentation system provides measurement and mapping of tissue elasticity for small specimens with high scanning speed. Experiments were performed on 27 silicone tissue-mimicking phantoms with different Young's moduli, which were also measured by uniaxial compression tests. The regression coefficient of the indentation force to the indentation depth (N mm(-1)) was used as an indicator of the stiffness of tissue under air jet indentation. Results showed that the stiffness coefficients measured by the current system correlated well with the corresponding Young's moduli obtained by conventional mechanical testing (r = 0.89, p < 0.001). Preliminary in vivo tests also showed that the change of soft tissue stiffness with and without the contraction of the underlying muscles in the hand could be differentiated by the current measurement. This system may have broad applications in tissue assessment and characterization where alterations of mechanical properties are involved, in particular with the potential of noncontact micro-indentation for tissues.
                  Cover page: An optical coherence tomography (OCT)-based air jet indentation system for measuring the mechanical properties of soft tissuesCreative Commons 'BY' version 4.0 license
                  • Article
                  • Peer Reviewed
                  UC Berkeley Previously Published Works (2020)
                  The previously developed bistable amphoteric native defect (BAND) model is used for a comprehensive explanation of the unique photophysical properties and for understanding the remarkable performance of perovskites as photovoltaic materials. It is shown that the amphoteric defects in the donor (acceptor) configuration capture a fraction of photoexcited electrons (holes) dividing them into two groups: higher-energy bright and lower-energy dark electrons (holes). The spatial separation of the dark electrons and dark holes and the k-space separation of the bright and dark charge carriers reduce electron-hole recombination rates, emulating the properties of an ideal photovoltaic material with a balanced, spatially separated transport of electrons and holes. The BAND model also offers a straightforward explanation for the exceptional insensitivity of the photovoltaic performance of polycrystalline perovskite films to structural and optical inhomogeneities. The blue-shifted radiative recombination of bright electrons and holes results in a large anti-Stokes effect that provides a quantitative explanation for the spectral dependence of the laser cooling effect measured in perovskite platelets.
                    Cover page: The Bright Side and Dark Side of Hybrid Organic–Inorganic Perovskites
                    • Article
                    • Peer Reviewed
                    UC Davis Previously Published Works (2020)
                    Brown adipose tissue (BAT) is an important target for obesity treatment and prevention. Soluble epoxide hydrolase (sEH) converts bioactive epoxy fatty acids (EpFAs) into less active diols. sEH inhibitors (sEHI) are beneficial in many chronic diseases by stabilizing EpFAs. However, roles of sEH and sEHI in brown adipogenesis and BAT activity in treating diet-induced obesity (DIO) have not been reported. sEH expression was studied in in vitro models of brown adipogenesis and the fat tissues of DIO mice. The effects of the sEHI, trans-4-{4-[3-(4-trifluoromethoxy-phenyl)-ureido]-cyclohexyloxy-benzoic acid (t-TUCB), were studied in vitro and in the obese mice via mini osmotic pump delivery. sEH expression was increased in brown adipogenesis and the BAT of the DIO mice. t-TUCB promoted brown adipogenesis in vitro. Although t-TCUB did not change body weight, fat pad weight, or glucose and insulin tolerance in the obese mice, it decreased serum triglycerides and increased protein expression of genes important for lipid metabolism in the BAT. Our results suggest that sEH may play a critical role in brown adipogenesis, and sEHI may be beneficial in improving BAT protein expression involved in lipid metabolism. Further studies using the sEHI combined with EpFA generating diets for obesity treatment and prevention are warranted.
                      Cover page: Soluble Epoxide Hydrolase Inhibition by t-TUCB Promotes Brown Adipogenesis and Reduces Serum Triglycerides in Diet-Induced Obesity
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