California State University, Long Beach
  • Long Beach, California, United States
Recent publications
High levels of 4-hydroxynonenal (HNE), arising from lipid peroxidation, and HNE-modified proteins have been identified in postmortem brains of aging and Alzheimer's disease (AD) patients. The goal of this study is to understand the effect of HNE modification on the structure and function of recombinant apolipoprotein E3 (apoE3) and apolipoprotein E4 (apoE4), which play a critical role in brain cholesterol homeostasis. The two isoforms differ in a single amino acid at position 112: Cys in apoE3 and Arg in apoE4. Immunoblot with HNE-specific antibody indicates HNE modification of apoE3 and apoE4 with a major band at ~36 kDa, while LC-MS/MS revealed Michael addition at His140 (60-70% abundance) and His299 (3-5% abundance) in apoE3 and apoE4, and Cys112-adduct in apoE3 (75% abundance). Circular dichroism spectroscopy revealed no major differences in the overall secondary structure or helical content between unmodified and HNE modified apoE. HNE modification did not affect their ability to promote cholesterol efflux from J774.1 macrophages. However, it led to a 3-fold decrease in their ability to bind lipids and 25-50% decrease in the ability of cerebral cortex endothelial cells to uptake lipoproteins bearing HNE-modified HNE-apoE3 or HNE-apoE4 as noted by fluorescence microscopy and flow cytometry. Taken together, the data indicate that HNE modification impairs lipid binding and cellular uptake of both isoforms, and that apoE3, bearing a Cys, offers a protective role by sequestering lipid peroxidation products that would otherwise cause indiscriminate damage to biomolecules. ApoE4, lacking Cys, is unable to protect against oxidative damage that is commensurate with aging.
This qualitative study utilized a Critical Race Feminista approach to explore the experiences of graduate Students of Color with racial microaffirmations. Racial microaffirmations are the subtle verbal and nonverbal strategies People of Color engage that affirm each other’s dignity, integrity, and shared humanity. These moments of shared cultural intimacy allow People of Color to feel acknowledged, respected, and valued in a society that constantly and perpetually seeks to dehumanize them. A Critical Race Feminista approach is grounded in Critical Race Theory (CRT) and Chicana feminist theoretical foundations. These theories guide the overall research design, and specifically, the methodological process. Four group pláticas were conducted with 30 students who also participated in the co-construction of knowledge during data analysis. This analysis revealed how racial microaffirmations can be embodied experiences, as sensory forms of knowledge that connect us to shared cultural intimacies and can serve as strategies for healing from racial traumas.
On a global scale, most earthquake casualties are the result of non-engineered buildings (N-EBs) collapsing in developing regions of the world. This is because developing countries present the unfortunate combination of high population densities, lack of resources, corruption, and a lack of design and construction knowhow needed in seismic regions. Over the last decades, a significant research effort has been dedicated to introducing low-cost seismic protection strategies that could be implemented on a large scale in developing regions of the world. This paper presents those state-of-the-art technologies. The purpose of this paper is to provide an overview of the many available systems, and underline the characteristics of these technology, to expand the range of applicability of each system, and to contribute to its state of development.
Conflict can be hurtful for anyone; however, individuals who take conflict personally (personalizers) may be uniquely affected by these interactions. We anticipated that both perceived intentionality and intensity of hurt feelings would either fully or partially mediate personalizers’ relational distancing response. Results of the structural equation model (SEM) uncovered that personalizers’ degree of emotional pain fully mediated the extent to which they distanced themselves from their partner, whereas their perceptions of intent played no meaningful role, either in full or part, in this process. Theoretical implications and practical suggestions for navigating conflict with personalizers are discussed.
Nucleate boiling is a phenomenon of significant importance in a broad range of industries. Increasing boiling performance parameters could lead to more efficient power plants and better electronics thermal management. However, difficulties associated with studying this extremely complex phenomenon have prevented a meaningful progress in the area of boiling heat transfer enhancement. In this paper, we implement a laser-based controlled bubble generation technique to enable accurate phenomenological studies of the boiling process. We present details of the transient focused-laser heating mechanism used to nucleate a microscale vapor embryo on the boiling surface. We present high-speed optical imaging data showing how this vapor embryo grows into a bubble using electrically applied background heat flux. Unlike the currently available artificial bubble generation approaches, which either generate unphysical bubbles or are extremely difficult to implement, we show that the laser-nucleated controlled single bubble demonstrates bubble ebullition characteristics closely representative of naturally occurring bubbles in nucleate pool boiling.
The catalytic activity and selectivity of two different water-soluble palladium nanoparticles capped with 5-(trimethylammonio)pentanethiolate and 6-(carboxylate)hexanethiolate ligands are investigated using the catalytic reaction of allyl benzene. The results show that the regioselective transformation of allyl benzene to 3-phenylpropanal occurs at room temperature and under atmospheric pressure in neat water via a Tsuji–Wacker type oxidation. Conventionally, the Tsuji–Wacker oxidation promotes the Markovnikov oxidation of terminal alkenes to their respective ketones in the presence of dioxygen. Water-soluble Pd nanoparticles, however, catalyze the anti-Markovnikov oxidation of allyl benzene to 3-phenylpropanal in up to 83% yields. Catalytic results of other aromatic alkenes suggest that the presence of benzylic hydrogen is a key to the formation of a p-allyl Pd intermediate and the anti-Markovnikov addition of H2O. The subsequent b-H elimination and tautomerization contribute to the formation of aldehyde products. Water-soluble Pd nanoparticles are characterized using nuclear magnetic resonance (NMR), UV–vis spectroscopy, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). Catalysis results are examined using 1H NMR and/or GC-MS analyses of isolated reaction mixtures.
In this study we simultaneously tested theoretically specified predictions from relational turbulence theory (RTT) using a fully latent structural regression model. A total of 807 college students in dating relationships responded to survey items measuring variables embedded in RTT, including relationship parameters (relational uncertainty and interdependence), biased cognitive appraisals, emotions, relational communication, and relational turbulence. Results from structural equation modeling revealed that RTT predictions were consistent with our data, but a respecified model with less restrictive constraints was a better fit. This less restrictive model allowed relational uncertainty to predict negative affect, and partner interference and facilitation to predict biased cognitive appraisals. Propositions of RTT were sustained.
An ideal adsorbent for separation requires optimizing both storage capacity and selectivity, but maximizing both or achieving a desired balance remain challenging. Herein, a de‐linker strategy is proposed to address this issue for metal‐organic frameworks (MOFs). Broadly speaking, the de‐linker idea targets a class of materials that may be viewed as being intermediate between zeolites and MOFs. Its feasibility is shown here by a series of ultra‐microporous MOFs (SNNU‐98‐M, M = Mn, Co, Ni, Zn). SNNU‐98 exhibit high volumetric C2H2 uptake capacity under low and ambient pressures (175.3 cm3 cm‐3 @ 0.1 bar, 222.9 cm3 cm‐3 @ 1 bar, 298 K), as well as extraordinary selectivity (2405.7 for C2H2/C2H4, 22.7 for C2H2/CO2). Remarkably, SNNU‐98‐Mn can efficiently separate C2H2 from C2H2/CO2 and C2H2/C2H4 mixtures with a benchmark C2H2/C2H4 (1/99) breakthrough time of 2325 min g‐1, and produce 99.9999% C2H4 with a productivity up to 64.6 mmol g‐1, surpassing values of reported MOF adsorbents.
An ideal adsorbent for separation requires optimizing both storage capacity and selectivity, but maximizing both or achieving a desired balance remain challenging. Herein, a de‐linker strategy is proposed to address this issue for metal‐organic frameworks (MOFs). Broadly speaking, the de‐linker idea targets a class of materials that may be viewed as being intermediate between zeolites and MOFs. Its feasibility is shown here by a series of ultra‐microporous MOFs (SNNU‐98‐M, M = Mn, Co, Ni, Zn). SNNU‐98 exhibit high volumetric C2H2 uptake capacity under low and ambient pressures (175.3 cm3 cm‐3 @ 0.1 bar, 222.9 cm3 cm‐3 @ 1 bar, 298 K), as well as extraordinary selectivity (2405.7 for C2H2/C2H4, 22.7 for C2H2/CO2). Remarkably, SNNU‐98‐Mn can efficiently separate C2H2 from C2H2/CO2 and C2H2/C2H4 mixtures with a benchmark C2H2/C2H4 (1/99) breakthrough time of 2325 min g‐1, and produce 99.9999% C2H4 with a productivity up to 64.6 mmol g‐1, surpassing values of reported MOF adsorbents.
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5,555 members
Andreas Bill
  • Department of Physics & Astronomy
Michael Peterson
  • Department of Physics & Astronomy
Thomas Alex Washington
  • College of Health & Human Services
Brian T Livingston
  • Department of Biological Sciences
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