UMBC Keith R. Porter Imaging Facility

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http://hdl.handle.net/11603/27438
The Keith R. Porter Imaging Facility (KPIF) of the College of Natural and Mathematical Sciences provides shared microscopy resources for biological and materials science research. Equipment and services are available to all faculty and staff at UMBC, as well as the surrounding academic and industrial communities. Instruments are located in the Biological Sciences, Physics and Interdisciplinary Life Sciences buildings. KPIF staff support all aspects of imaging, including protocol development, sample preparation, equipment training and image processing.

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Now showing 1 - 6 of 6
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    Effect of high-energy radiation on the electrical and optical characteristics of bioactive glasses
    (SPIE, 2024-03-19) Tauraso, Aria; Machuga, Krishna S.; McAdams, Joel; Su, Ching Hua; Cullum, Brian; deCarvalho, Tagide; Prasad, Narasimha S.; Arnold, Bradley; Choa, Fow-Sen; Mandal, Kamdeo D.; Singh, Narsingh
    SignificanceThe glassy and crystalline hydroxyapatites that affect the metabolic processes such as tissue growth and healing are affected by the electrical, electrochemical, and optical properties investigated in this study.AimThe aim of the present study is to determine effects of high-energy radiation and impurities on the electrical and optical properties of hydroxyapatites responsible for tissue growth and tendency of glass forming ability.ApproachThe approach of the study involves synthesis using carbonates, oxides, silicates, phosphates, and borates of parent materials using elevated temperature and low-temperature flux process. High-energy radiation effects were studied by exposing hydroxyapatites with 5μ CiCs¹³⁷ γ- ray source. Morphology was studied to determine dissolution and glass formation of additives such as titanium, gallium, and selenium.ResultsIrradiation of silicate bio glasses showed huge effects on the electrical characteristics, such as dielectric constant (hence polarity) and resistivity of the materials while optical properties showed insignificant changes. Morphological studies showed transition of faceted to nonfaceted structure.ConclusionExposure for the bias voltage of 50 to 1000 mV in the range of 100 to 100000 Hz frequency range showed a large decrease in the dielectric constant and increase in resistivity. The IR and Raman spectra for irradiated glasses exposed for 24 h showed a small change. Morphological results showed that substitution of gallium, magnesium, and /or titanium affects the transition to the glass formation. The addition of selenium showed enormous potential to improve the mixing and glass formation without titanium and gallium precipitates in the matrix.
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    Raaz: A Transdisciplinary Exploration at the Intersection of Bioart, HCI, and Community Engagement
    (Frontiers, 2022-03-17) Stamato, Lydia; Higgins, Erin; Prottoy, Hasan Mahmud; Asgarali-Hoffman, S. Nisa; Scheifele, Lisa; Dusman, Linda; deCarvalho, Tagide; Ascencao, Teresa; Hamidi, Foad
    Living organisms and their biological properties, including the capacity for transformation and representation of information, offer exciting and inspiring opportunities for transdisciplinary art and design explorations. While an emerging body of work is increasingly investigating the possibilities at the intersection of interactive computing, biology, and art, more work is needed to investigate the potential of these approaches for supporting community and public engagement and participation in art, science, and technology. In this project, we describe a multimedia transdisciplinary bioart installation and hands-on agar art activity that we presented to members of the public in a community biology lab setting. Using short interviews, observations, and questionaries, we investigated attendees' reactions and impressions of the experience and found that the event generated transdisciplinary reflections, invited participants to bring their previous knowledge and experience to bear in engaging with different aspects of the work, and that the audience benefited from contextualization by artists.
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    Effect of high energy radiation on electrical properties of synthetic bone materials
    (Wiley, 2024-02-02) Machuga, Krishna S.; Tauraso, Aria; Tauraso, Aria; Su, Ching Hua; Cullum, Brian; Arnold, Bradley; Choa, Fow-Sen; Prasad, Narasimha; Singh, Narsingh
    Hydroxyapatites have been investigated since past six decades as laser host materials. Because of their important roles in bone and teeth, these have been subjects of recent investigations. Gallium and titanium have great potential for decreasing the depletion of calcium and reducing osteoporosis. The electrical properties and polarity play important roles in regeneration of the bones. We observed growth of grains in selenium-doped gallium and titanium containing silicate hydroxyapatites. Observed morphology showed non-facetted microstructures and it helped in achieving larger grains. For the material processed for the period of longer than 70 h, we did not observe any difference in the dielectric constant and resistivity of the selenium-doped materials. For irradiating the materials, a Cs-137 γ-radiation with 5 µm curie dose was used up to 100 h. We observed that the dielectric constant and resistivity at different frequencies ranging from 100 to 100 000 Hz were affected by the high energy radiation. However, bias voltage in the range of 50–1 000 mV did no alter the dielectric constant or resistivity. This indicated that the breakdown of the material did not occur for this bias range.
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    Simultaneous entry as an adaptation to virulence in a novel satellite-helper system infecting Streptomyces species
    (Nature, 2023-10-31) deCarvalho, Tagide; Mascolo, Elia; Caruso, Steven; López-Pérez, Júlia; Weston-Hafer, Kathleen; Shaffer, Christopher; Erill, Ivan
    Satellites are mobile genetic elements that are dependent upon the replication machinery of their helper viruses. Bacteriophages have provided many examples of satellite nucleic acids that utilize their helper morphogenic genes for propagation. Here we describe two novel satellite-helper phage systems, Mulch and Flayer, that infect Streptomyces species. The satellites in these systems encode for encapsidation machinery but have an absence of key replication genes, thus providing the first example of bacteriophage satellite viruses. We also show that codon usage of the satellites matches the tRNA gene content of the helpers. The satellite in one of these systems, Flayer, does not appear to integrate into the host genome, which represents the first example of a virulent satellite phage. The Flayer satellite has a unique tail adaptation that allows it to attach to its helper for simultaneous co-infection. These findings demonstrate an ever-increasing array of satellite strategies for genetic dependence on their helpers in the evolutionary arms race between satellite and helper phages.
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    The transcriptional regulator CtrA controls gene expression in Alphaproteobacteria phages: Evidence for a lytic deferment pathway
    (Frontiers, 2022-08-19) Mascolo, Elia; Adhikari, Satish; Caruso, Steven M.; deCarvalho, Tagide; Salvador, Anna Folch; Serra-Sagristà, Joan; Young, Ry; Erill, Ivan; Curtis, Patrick D.
    Pilitropic and flagellotropic phages adsorb to bacterial pili and flagella. These phages have long been used to investigate multiple aspects of bacterial physiology, such as the cell cycle control in the Caulobacterales. Targeting cellular appendages for adsorption effectively constrains the population of infectable hosts, suggesting that phages may have developed strategies to maximize their infective yield. Brevundimonas phage vB_BsubS-Delta is a recently characterized pilitropic phage infecting the Alphaproteobacterium Brevundimonas subvibrioides. Like other Caulobacterales, B. subvibrioides divides asymmetrically and its cell cycle is governed by multiple transcriptional regulators, including the master regulator CtrA. Genomic characterization of phage vB_BsubS-Delta identified the presence of a large intergenic region with an unusually high density of putative CtrA-binding sites. A systematic analysis of the positional distribution of predicted CtrA-binding sites in complete phage genomes reveals that the highly skewed distribution of CtrA-binding sites observed in vB_BsubS-Delta is an unequivocal genomic signature that extends to other pilli- and flagellotropic phages infecting the Alphaproteobacteria. Moreover, putative CtrA-binding sites in these phage genomes localize preferentially to promoter regions and have higher scores than those detected in other phage genomes. Phylogenetic and comparative genomics analyses show that this genomic signature has evolved independently in several phage lineages, suggesting that it provides an adaptive advantage to pili/flagellotropic phages infecting the Alphaproteobacteria. Experimental results demonstrate that CtrA binds to predicted CtrA-binding sites in promoter regions and that it regulates transcription of phage genes in unrelated Alphaproteobacteria-infecting phages. We propose that this focused distribution of CtrA-binding sites reflects a fundamental new aspect of phage infection, which we term lytic deferment. Under this novel paradigm, pili- and flagellotropic phages exploit the CtrA transduction pathway to monitor the host cell cycle state and synchronize lysis with the presence of infectable cells.