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52. Accessible research experiences: A new paradigm for in-lab chemical education

Author

Baum, Marc M., Krider, Elizabeth S., and Moss, John A.

Subjects
Chemical research -- Educational aspects, Chemistry -- Study and teaching, Chemistry, Education, Science and technology
Abstract

The preliminary efforts to engage students in the physical sciences through research projects in environmental chemistry are described. The successful involvement of two demographics, community college (CC) students and female students in cutting-edge chemistry research suggests that recruiting methods were effective and the feedback from participants suggests that the chemistry projects selected by the students positively affected their career planning.

Published
2006

54. Novel multipurpose pod-intravaginal ring for the prevention of HIV, HSV, and unintended pregnancy: Pharmacokinetic evaluation in a macaque model

Author

Smith, James M., primary, Moss, John A., additional, Srinivasan, Priya, additional, Butkyavichene, Irina, additional, Gunawardana, Manjula, additional, Fanter, Rob, additional, Miller, Christine S., additional, Sanchez, Debbie, additional, Yang, Flora, additional, Ellis, Shanon, additional, Zhang, Jining, additional, Marzinke, Mark A., additional, Hendrix, Craig W., additional, Kapoor, Amita, additional, and Baum, Marc M., additional

Published
2017
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56. Pharmacokinetics and Preliminary Safety of Pod-Intravaginal Rings Delivering the Monoclonal Antibody VRC01-N for HIV Prophylaxis in a Macaque Model

Author

Zhao, Chunxia, primary, Gunawardana, Manjula, additional, Villinger, Francois, additional, Baum, Marc M., additional, Remedios-Chan, Mariana, additional, Moench, Thomas R., additional, Zeitlin, Larry, additional, Whaley, Kevin J., additional, Bohorov, Ognian, additional, Smith, Thomas J., additional, Anderson, Deborah J., additional, and Moss, John A., additional

Published
2017
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58. Topical Delivery of Tenofovir Disoproxil Fumarate and Emtricitabine from Pod-Intravaginal Rings Protects Macaques from Multiple SHIV Exposures

Author

Srinivasan, Priya, primary, Moss, John A., additional, Gunawardana, Manjula, additional, Churchman, Scott A., additional, Yang, Flora, additional, Dinh, Chuong T., additional, Mitchell, James M., additional, Zhang, Jining, additional, Fanter, Rob, additional, Miller, Christine S., additional, Butkyavichene, Irina, additional, McNicholl, Janet M., additional, Smith, Thomas J., additional, Baum, Marc M., additional, and Smith, James M., additional

Published
2016
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59. Combination Pod-Intravaginal Ring Delivers Antiretroviral Agents for HIV Prophylaxis: Pharmacokinetic Evaluation in an Ovine Model

Author

Moss, John A., primary, Butkyavichene, Irina, additional, Churchman, Scott A., additional, Gunawardana, Manjula, additional, Fanter, Rob, additional, Miller, Christine S., additional, Yang, Flora, additional, Easley, Jeremiah T., additional, Marzinke, Mark A., additional, Hendrix, Craig W., additional, Smith, Thomas J., additional, and Baum, Marc M., additional

Published
2016
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65. Isolation of PCR quality microbial community DNA from heavily contaminated environments

Author

Gunawardana, Manjula, primary, Chang, Simon, additional, Jimenez, Abraham, additional, Holland-Moritz, Daniel, additional, Holland-Moritz, Hannah, additional, La Val, Taylor P., additional, Lund, Craig, additional, Mullen, Madeline, additional, Olsen, John, additional, Sztain, Terra A., additional, Yoo, Jennifer, additional, Moss, John A., additional, and Baum, Marc M., additional

Published
2014
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68. Cultivated Vaginal Microbiomes Alter HIV-1 Infection and Antiretroviral Efficacy in Colonized Epithelial Multilayer Cultures

Author

Pyles, Richard B., primary, Vincent, Kathleen L., additional, Baum, Marc M., additional, Elsom, Barry, additional, Miller, Aaron L., additional, Maxwell, Carrie, additional, Eaves-Pyles, Tonyia D., additional, Li, Guangyu, additional, Popov, Vsevolod L., additional, Nusbaum, Rebecca J., additional, and Ferguson, Monique R., additional

Published
2014
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70. The Fuel Cell Model of Abiogenesis: A New Approach to Origin-of-Life Simulations

Author

Barge, Laura M., primary, Kee, Terence P., additional, Doloboff, Ivria J., additional, Hampton, Joshua M.P., additional, Ismail, Mohammed, additional, Pourkashanian, Mohamed, additional, Zeytounian, John, additional, Baum, Marc M., additional, Moss, John A., additional, Lin, Chung-Kuang, additional, Kidd, Richard D., additional, and Kanik, Isik, additional

Published
2014
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71. Global Expression of Molecular Transporters in the Human Vaginal Tract: Implications for HIV Chemoprophylaxis

Author

Gunawardana, Manjula, primary, Mullen, Madeline, additional, Moss, John A., additional, Pyles, Richard B., additional, Nusbaum, Rebecca J., additional, Patel, Jignesh, additional, Vincent, Kathleen L., additional, Wang, Charles, additional, Guo, Chao, additional, Yuan, Yate-Ching, additional, Warden, Charles D., additional, and Baum, Marc M., additional

Published
2013
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73. Safety and Pharmacokinetics of Intravaginal Rings Delivering Tenofovir in Pig-Tailed Macaques

Author

Moss, John A., primary, Malone, Amanda M., additional, Smith, Thomas J., additional, Butkyavichene, Irina, additional, Cortez, Cassandra, additional, Gilman, Joshua, additional, Kennedy, Sean, additional, Kopin, Etana, additional, Nguyen, Cali, additional, Sinha, Preetha, additional, Hendry, R. Michael, additional, Guenthner, Patricia, additional, Holder, Angela, additional, Martin, Amy, additional, McNicholl, Janet, additional, Mitchell, James, additional, Pau, Chou-Pong, additional, Srinivasan, Priya, additional, Smith, James M., additional, and Baum, Marc M., additional

Published
2012
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74. Simultaneous Delivery of Tenofovir and Acyclovir via an Intravaginal Ring

Author

Moss, John A., primary, Malone, Amanda M., additional, Smith, Thomas J., additional, Kennedy, Sean, additional, Kopin, Etana, additional, Nguyen, Cali, additional, Gilman, Josh, additional, Butkyavichene, Irina, additional, Vincent, Kathleen L., additional, Motamedi, Massoud, additional, Friend, David R., additional, Clark, Meredith R., additional, and Baum, Marc M., additional

Published
2012
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75. Validation of a new spectrometer for noninvasive measurement of cardiac output

Author

Baum, Marc M., Kumar, Sasi, Moss, John A., Wagner, Peter D., Baum, Marc M., Kumar, Sasi, Moss, John A., and Wagner, Peter D.

Abstract

Acetylene is a blood-soluble gas and for many years its uptake rate during rebreathing tests has been used to calculate the flow rate of blood through the lungs (normally equal to cardiac output) as well as the volume of lung tissue. A new, portable, noninvasive instrument for cardiac output determination using the acetylene uptake method is described. The analyzer relies on nondispersive IR absorption spectroscopy as its principle of operation and is configured for extractive (side-stream) sampling. The instrument affords exceptionally fast (30 ms, 10%–90%, 90%–10%, at 500 mL min–1 flow rates), interference-free, simultaneous measurement of acetylene, sulfur hexafluoride (an insoluble reference gas used in the cardiac output calculation), and carbon dioxide (to determine alveolar ventilation), with good (typically ±2% full-scale) signal-to-noise ratios. Comparison tests with a mass spectrometer using serially diluted calibration gas samples gave excellent (R2>0.99) correlation for all three gases, validating the IR system's linearity and accuracy. A similar level of agreement between the devices also was observed during human subject C2H2 uptake tests (at rest and under incremental levels of exercise), with the instruments sampling a common extracted gas stream. Cardiac output measurements by both instruments were statistically equivalent from rest to 90% of maximal oxygen consumption; the physiological validity of the measurements was confirmed by the expected linear relationship between cardiac output and oxygen consumption, with both the slope and intercept in the published range. These results indicate that the portable, low-cost, rugged prototype analyzer discussed here is suitable for measuring cardiac output noninvasively in a point-of-care setting.

Published
2004

87. Beta- Lactam Antibiotics Stimulate Biofilm Formation in Non-Typeable Haemophilus influenzae by Up-Regulating Carbohydrate Metabolism.

Author

Wu, Siva, Li, Xiaojin, Gunawardana, Manjula, Maguire, Kathleen, Guerrero-Given, Debbie, Schaudinn, Christoph, Wang, Charles, Baum, Marc M., and Webster, Paul

Subjects
BETA-lactamase inhibitors, HAEMOPHILUS influenzae, CARBOHYDRATE metabolism, PHYSIOLOGICAL effects of antibiotics, MEDICAL care costs, BIOFILMS, THERAPEUTICS
Abstract

Non-typeable Haemophilus influenzae (NTHi) is a common acute otitis media pathogen, with an incidence that is increased by previous antibiotic treatment. NTHi is also an emerging causative agent of other chronic infections in humans, some linked to morbidity, and all of which impose substantial treatment costs. In this study we explore the possibility that antibiotic exposure may stimulate biofilm formation by NTHi bacteria. We discovered that sub-inhibitory concentrations of beta-lactam antibiotic (i.e., amounts that partially inhibit bacterial growth) stimulated the biofilm-forming ability of NTHi strains, an effect that was strain and antibiotic dependent. When exposed to sub-inhibitory concentrations of beta-lactam antibiotics NTHi strains produced tightly packed biofilms with decreased numbers of culturable bacteria but increased biomass. The ratio of protein per unit weight of biofilm decreased as a result of antibiotic exposure. Antibiotic-stimulated biofilms had altered ultrastructure, and genes involved in glycogen production and transporter function were up regulated in response to antibiotic exposure. Down-regulated genes were linked to multiple metabolic processes but not those involved in stress response. Antibiotic-stimulated biofilm bacteria were more resistant to a lethal dose (10 µg/mL) of cefuroxime. Our results suggest that beta-lactam antibiotic exposure may act as a signaling molecule that promotes transformation into the biofilm phenotype. Loss of viable bacteria, increase in biofilm biomass and decreased protein production coupled with a concomitant up-regulation of genes involved with glycogen production might result in a biofilm of sessile, metabolically inactive bacteria sustained by stored glycogen. These biofilms may protect surviving bacteria from subsequent antibiotic challenges, and act as a reservoir of viable bacteria once antibiotic exposure has ended. [ABSTRACT FROM AUTHOR]

Published
2014
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89. Integrated Method for the Measurement of Trace Atmospheric Bases.

Author

Key, Daryl, Stihle, Jerome, Petit, Jean-Eudes, Bonnet, Cécile, Depernon, Lauriane, Liu, Oscar, Kennedy, Sean, Latimer, Robyn, Burgoyne, Marnie, Wanger, Darcy, Webster, Alexandre, Casunuran, Samantha, Hidalgo, Sergio, Thomas, Mark, Moss, John A., and Baum, Marc M.

Subjects
HIGH performance liquid chromatography, GAS chromatography, TRACE analysis, MASS spectrometry, BASES (Chemistry), ATMOSPHERIC chemistry
Abstract

The article presents a study which analyzes the potential of integrated method for the measurement of trace atmospheric bases. The project uses a chromatography instrumentation which consists a high performance liquid chromatography with mass spectrometric detection and a gas chromatography. An overview of the preparation of authentic samples is provided. The conducted Denuder and Impinger efficiency tests were highlighted.

Published
2011

91. Hydrogen Cyanide Exhaust Emissions from In-Use Motor Vehicles.

Author

Baum, Marc M., Moss, John A., Pastel, Stephen H., and Poskrebyshev, Gregory A.

Subjects
*CYANIDES, *MOTOR vehicles, *EMISSIONS (Air pollution), *AIR pollution, *CARBON monoxide, *POISONOUS gases, *NITRIC oxide, *NITROGEN compounds
Abstract

Motor vehicle exhaust emissions are known to contain hydrogen cyanide (HCN), but emission rate data are scarce and, in the case of idling vehicles, date back over 20 years. For the first time, vehicular HCN exhaust emissions from a modern, in-use fleet at idle have been measured. The 14 tested light duty motor vehicles were operating at idle as these conditions are associated with the highest risk exposure scenarios (i.e., enclosed spaces). Vehicular HCN was detected in 89% of the sampled exhaust streams and did not correlate with instantaneous air-fuel-ratio or with any single, coemitted pollutant. However, a moderate correlation between HCN emissions and the product of carbon monoxide and nitric oxide emissions was observed under cold-start conditions. Fleet average, cold-start, undiluted HCN emissions were 105 ± 97 ppbV (maximum: 278 ppbV), whereas corresponding emissions from vehicles operating under stabilized conditions were 79 ± 71 ppbV (maximum: 245 ppbV); mean idle fleet HCN emission rates were 39 ± 35 and 21 ± 18 μg-min-1 for cold-start and stabilized vehicles, respectively. The significance of these results is discussed in terms of HCN emissions inventories in the South Coast Air Basin of California and of health risks due to exposure to vehicular HCN. [ABSTRACT FROM AUTHOR]

Published
2007
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92. Pharmacokinetics of Injectable, Long-Acting Nevirapine for HIV Prophylaxis in Breastfeeding Infants

Author

Cortez, John M., Quintero, Rafaela, Moss, John A., Beliveau, Martin, Smith, Thomas J., and Baum, Marc M.

Abstract

ABSTRACTMother-to-child transmission (MTCT) of HIV-1 remains a global health problem. The World Health Organization (WHO) recommendations advise the administration of a once-daily, oral, prophylactic regimen of the nonnucleoside reverse transcriptase inhibitor nevirapine (NVP) from birth until 4 to 6 weeks of age for infants born to HIV-infected mothers in regions without access to safe and nutritionally adequate alternatives to breast milk. A critical factor driving the successful implementation of the WHO guidelines involves sustaining high adherence to the frequent dosing. With these challenges in mind, we have developed the first injectable, sustained-release NVP formulations with the goal of providing, for 6 weeks or longer, preventative plasma drug levels from a single subcutaneous administration at birth. The long-acting NVP consists of large (>50 μm), monodisperse NVP particles coated with biocompatible polymers that control the drug release kinetics. Two lead formulations exhibiting burst-free, sustained-release kinetics for up to 75 days in vitrowere developed. Subsequent in vivostudies in rats demonstrated no toxicity related to the formulations. Rat plasma NVP concentrations were above the analytical assay's limit of quantification for up to 28 days. Pharmacokinetic analysis of the rat plasma NVP concentration-time data allowed absorption rate constants to be calculated. These data then were used to simulate infant NVP exposure from a single injected dose (<200 mg) of our long-acting formulations, demonstrating preliminary feasibility of the technology to maintain safe, preventative NVP plasma levels (0.2 to 3.0 μg ml−1) for 6 weeks or longer.

Published
2014
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93. Pollution monitoring employs the UV

Author

Baum, Marc M.

Subjects
Environmental monitoring -- Equipment and supplies, Ultraviolet spectrometry -- Usage, Business, Electronics and electrical industries, Engineering and manufacturing industries
Published
1994

94. Simultaneous Delivery of Tenofovir and Acyclovir via an Intravaginal Ring

Author

Moss, John A., Malone, Amanda M., Smith, Thomas J., Kennedy, Sean, Kopin, Etana, Nguyen, Cali, Gilman, Josh, Butkyavichene, Irina, Vincent, Kathleen L., Motamedi, Massoud, Friend, David R., Clark, Meredith R., and Baum, Marc M.

Abstract

ABSTRACTVaginal microbicides may play an important role in protecting women from HIV infection. A strong synergy between HSV and HIV has been observed, and epidemiological studies demonstrate that HSV infection increases the risk of HIV acquisition. Incorporation of the antiretroviral tenofovir (TFV) along with the antiherpetic acyclovir (ACV) into combination intravaginal rings (IVRs) for sustained mucosal delivery of both compounds could lead to increased microbicide product adherence and efficacy compared with conventional vaginal formulations. A novel, dual-protection “pod IVR” platform developed in-house and delivering ACV and TFV was evaluated in rabbit and sheep models. The devices were safe and exhibited sustained release of both drugs independently and at controlled rates over the 28-day studies. Daily release rates were estimated based on residual drug content of the used devices: rabbits, 343 ± 335 μg day−1(ACV) and 321 ± 207 μg day−1(TFV); sheep, 174 ± 14 μg day−1(ACV) and 185 ± 34 μg day−1(TFV). Mean drug levels in sheep vaginal samples were as follows: secretions, 5.25 ± 7.31 μg ml−1(ACV) and 20.6 ± 16.2 μg ml−1(TFV); cervicovaginal lavage fluid, 118 ± 113 ng ml−1(ACV) and 191 ± 125 ng ml−1(TFV); tissue, 173 ng g−1(ACV) and 93 ng g−1(TFV). An in vitro-in vivocorrelation was established for both drugs and will allow the development of future formulations delivering target levels for prophylaxis and therapy. These data suggest that the IVR based on the pod design has potential in the prevention of transmission of HIV-1 and other sexually transmitted pathogens.

Published
2011
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95. Determination of phosphate/arsenate by a modified molybdenum blue method and reduction of arsenate by S2O4 2−

Author

Tsang, Susanna, Phu, Frank, Baum, Marc M., and Poskrebyshev, Gregory A.

Subjects
*MOLYBDENUM, *ARSENATES, *PHOSPHATES, *SULFURIC acid
Abstract

Abstract: A modified molybdenum blue method for fast and accurate measurement of arsenate and phosphate in aqueous solution at concentrations below 10μmoll−1 is reported. The modification consists of optimizing the composition of the molybdenum-containing solution (potassium antimony tartrate, ammonium molybdate, sulfuric acid). Selective reduction of arsenate by sodium dithionite is used to determine phosphate concentrations, and for the speciation of arsenate and arsenite, in an aqueous mixture according to the scheme developed by Johnston and Pilson. Sodium dithionite is used for the first time to achieve complete, fast (<10min), and selective reduction of arsenate in neutral solution. These two significant improvements afforded a colorimetric limit for As detection near 1ppb, which easily meets the requirements imposed by the revised EPA threshold levels for As in drinking water. [Copyright &y& Elsevier]

Published
2007
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96. Loss of genital epithelial barrier function is greater with depot-medroxyprogesterone acetate than intravaginal rings that release etonogestrel and ethinyl estradiol.

Author

Liu M, Miguel RDV, Calla NEQ, Aceves KM, Fritts L, Miller CJ, Moss JA, Baum MM, and Cherpes TL

Abstract

The injectable progestin depot-medroxyprogesterone acetate (DMPA) is a popular contraceptive choice in sub-Saharan Africa although mouse models indicate it weakens genital epithelial integrity and barrier function and increases susceptibility to genital infection. The intravaginal ring NuvaRing ® is another contraceptive option that like DMPA suppresses hypothalamic pituitary ovarian (HPO) axis function with local release of progestin (etonogestrel) and estrogen (ethinyl estradiol). As we previously reported that treating mice with DMPA and estrogen averts the loss of genital epithelial integrity and barrier function induced by DMPA alone, in the current investigation we compared genital levels of the cell-cell adhesion molecule desmoglein-1 (DSG1) and genital epithelial permeability in rhesus macaques (RM) treated with DMPA or a NuvaRing ® re-sized for RM (N-IVR). While these studies demonstrated comparable inhibition of the HPO axis with DMPA or N-IVR, DMPA induced significantly lower genital DSG1 levels and greater tissue permeability to intravaginally administered low molecular mass molecules. By identifying greater compromise of genital epithelial integrity and barrier function in RM administered DMPA vs. N-IVR, our results add to the growing body of evidence that indicate DMPA weakens a fundamental mechanism of anti-pathogen host defense in the female genital tract.

Published
2023
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97. Experimental approaches to investigating the vaginal biofilm microbiome.

Author

Baum MM, Gunawardana M, and Webster P

Subjects
Female, Humans, In Situ Hybridization, Fluorescence, Microscopy, Electron, Scanning, Microscopy, Electron, Transmission, Microscopy, Fluorescence, Biofilms, Microbiological Techniques, Microbiota, Vagina microbiology
Abstract

Unraveling the complex ecology of the vaginal biofilm microbiome relies on a number of complementary techniques. Here, we describe the experimental approaches for studying vaginal microbial biofilm samples with a focus on specimen preparation for subsequent analysis. The techniques include fluorescence microscopy, fluorescence in situ hybridization, and scanning and transmission electron microscopy. Isolation of microbial DNA and RNA from these samples is covered along with a brief discussion of chemical analysis methods.

Published
2014
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