Digital Commons Network^™

A Super-Hard High Entropy Boride Containing Hf, Mo, Ti, V, And W, Suzana Filipovic, Nina Obradovic, Greg E. Hilmas, William G. Fahrenholtz, Donald W. Brenner, Jon Paul Maria, Douglas E. Wolfe, Eva Zurek, Xiomara Campilongo, Stefano Curtarolo

Materials Science and Engineering Faculty Research & Creative Works

Super-Hard (Hf,Mo,Ti,V,W)B2 Was Synthesized by Boro-Carbothermal Reduction and Densified by Spark Plasma Sintering. This Composition Was Produced for the First Time as a Single-Phase Ceramic in the Present Research. the Optimized Ceramic Had a Single Hexagonal AlB2-Type Crystalline Phase with a Grain Size of 3.8 µm and Homogeneous Distribution of the Constituent Metals. the Vickers Hardness Exhibited the Indentation Size Effect, Increasing from 27 GPa at a Load of 9.8 N to as High as 66 GPa at a Load of 0.49 N. This is the Highest Hardness Reported to Date for High Entropy Boride Ceramics.

Ultrasensitive Tapered Optical Fiber Refractive Index, Erem Ujah, Meimei Lai, Gymama Slaughter

Electrical & Computer Engineering Faculty Publications

Refractive index (RI) sensors are of great interest for label-free optical biosensing. A tapered optical fiber (TOF) RI sensor with micron-sized waist diameters can dramatically enhance sensor sensitivity by reducing the mode volume over a long distance. Here, a simple and fast method is used to fabricate highly sensitive refractive index sensors based on localized surface plasmon resonance (LSPR). Two TOFs (l = 5 mm) with waist diameters of 5 µm and 12 µm demonstrated sensitivity enhancement at λ = 1559 nm for glucose sensing (5-45 wt%) at room temperature. The optical power transmission decreased with increasing glucose concentration due …

“Revisiting The Past”: A Redescription Of Physaloptera Retusa (Nemata, Physalopteridae) From Material Deposited In Museums And New Material From Amazon Lizards = “Revisitando O Passado”: Uma Redescrição De Physaloptera Retusa (Nemata, Physalopteridae) A Partir De Material Depositado Em Museus E Novo Material De Lagartos Amazônicos, Lílian Cristina Macedo, Yuri Willkens, Leandro Maurício Oliveira Da Silva, Scott Lyell Gardner, Francisco Tiago De Vasconcelos Melo, Jeannie Nascimento Dos Santos

Scott L. Gardner Publications

Abstract

Physaloptera Rudolphi, 1819 is a genus of nematodes that includes approximately 100 species parasitic in vertebrates around the world. From these, approximately 30 occur in the Neotropical region, with nine reported from neotropical reptiles. Physaloptera spp. are recognized by their distinct morphology of the apical end and characters of the reproductive system. However, despite the fact that the morphological characters for species diagnosis have been firmly established, we frequently find identification problems regarding poorly detailed descriptions and poorly preserved specimens. These may lead to taxonomic incongruencies. Physaloptera retusa (Rudolphi, 1819) is the most common species of the genus and …

Non-Thermal Atmospheric Pressure Plasma-Conditioned Root Dentin Promotes Attraction And Attachment Of Primary Human Dental Pulp Stem Cells In Real-Time Ex Vivo, Yeon Jee Yoo, Min Ji Kang, Hiran Perinpanayagam, Joo Cheol Park, Seung Ho Baek, Kee Yeon Kum

Dentistry Publications

This study investigated if non-thermal atmospheric pressure plasma (NTAPP) treatment of root dentin surfaces promotes human dental pulp stem cell (hDPSCs) adhesion. Freshly extracted human single-rooted teeth (n = 36) were decoronated and cut (first vertically, then horizontally) into root dentin slices (3 mm thick). Primary hDPSCs cultures were seeded onto slices randomly assigned to pretreatment groups (n = 9/group): NaOCl (1.5%), EDTA (17%) then NTAPP (Group I); NaOCl then NTAPP (Group II); NaOCl then EDTA (Group III); and NaOCl alone (Group IV). Cell viability and proliferation were measured using MTT assay with log-linear statistical analysis. Cell attachment and spreading …

Atomic Layer Deposition Of Sodium Fluoride Thin Films, Sara Kuraitis, Donghyeon Kang, Anil U. Mane, Hua Zhou, Jake Soares, Jeffrey W. Elam, Elton Graugnard

Materials Science and Engineering Faculty Publications and Presentations

The need for advanced energy conversion and storage devices remains a critical challenge amid the growing worldwide demand for renewable energy. Metal fluoride thin films are of great interest for applications in lithium-ion and emerging rechargeable battery technologies, particularly for enhancing the stability of the electrode-electrolyte interface and thereby extending battery cyclability and lifetime. Reported within, sodium fluoride (NaF) thin films were synthesized via atomic layer deposition (ALD). NaF growth experiments were carried out at reactor temperatures between 175 and 250 °C using sodium tert-butoxide and HF-pyridine solution. The optimal deposition temperature range was 175–200 °C, and the resulting …

Coal Fracturing Through Liquid Nitrogen Treatment: A Micro-Computed Tomography Study, Hamed Akhondzadeh, Alireza Keshavarz, Faisal Ur Rahman Awan, Ahmed Z. Al-Yaseri, Stefan Iglauer, Maxim Lebedev

Research outputs 2014 to 2021

Low permeability of coal has been a constant obstacle to economic production from coalbed methane reservoirs, and liquid nitrogen (LN₂) treatment has been investigated as one approach to address this issue. This study examined LN₂ fracturing of a bituminous coal at pore-scale through 3D X-ray micro-computed tomography. For this purpose, a cylindrical sample was immersed into LN₂ for 60 min. The micro-CT results clearly showed that the rapid freezing of the coal with LN₂ generated fracture planes with large apertures originating from the pre-existing cleats in the rock. This treatment also connected original cleats with …

Evaluation Of The Effectiveness Of Fluoridated And Non-Fluoridated Desensitizing Agents In Dentinal Tubule Occlusion Using Scanning Electron Microscopy. An In-Vitro Study, Ashwini Dessai, Neeta Shetty, N. Srikant

Open Access archive

Dentin hypersensitivity is primarily caused due to patent or exposed dentinal tubules. Nonfluoridated-desensitizing agents deposit hydroxycarbonate apatite (HCA), within the dentinal tubules, thereby relieving hypersensitivity. Fluoride-containing bioactive glass-based agents form fluorapatite which is less soluble when compared to hydroxyapatite and HCA. Materials and Methods: In this in vitro study forty dentin specimens obtained from extracted human premolars were divided randomly into four groups (n = 10): Group 1 - fluoridated bioactive glass (FBaG); Group 2 - bioactive glass (BaG); Group 3 - arginine calcium carbonate; Group 4 - saline. 37.5% phosphoric acid was used to ensure patent dentinal tubules. Test …

Hot Electron Chemistry On Bimetallic Plasmonic Nanoparticles, Bryn E. Merrill, Bingjie Zhang, Jerry Larue

Student Scholar Symposium Abstracts and Posters

Catalysis provides pathways for efficient and selective chemical reactions through the lowering of energy barriers for desired products. Gold nanoparticles (AuNP) show excellent promise as plasmonic catalysts. Localized surface plasmon resonances are oscillations of the electron bath at the surface of a nanoparticle that generate energetically intense electric fields and rapidly decay into energetically excited electrons. The excited electrons have the potential to destabilize strongly bound oxygen atoms through occupation of accessible anti-bonding orbitals. Tuning the anti-bonding orbitals to make them accessible for occupancy will be achieved by coating the AuNP in a thin layer of another transition metal, such …

Characterization Of Extracellular Vesicles Isolated From Human Milk Using A Precipitation-Based Method, Diana C. Bickmore, John Miklavcic

Food Science Faculty Articles and Research

Extracellular vesicles (EV) function in intercellular communication, and those in human milk may confer immunologic benefits to infants. Methods of EV isolation such as ultracentrifugation (UC) may not be feasible for the study of EVs in human milk due to the need for large sample volume. A technique to isolate EVs from a small volume of human milk using a precipitation reagent is described herein. Electron microscopy, nanoparticle tracking analysis, and semi-quantitative antibody array were conducted to confirm isolation of human milk EVs. Count, size, protein content, and fatty acid quantification of EVs were determined. This isolation technique yielded 8.9 …

Exploring The Use Of Pulsed Erbium Lasers To Retrieve A Zirconia Crown From A Zirconia Implant Abutment, Ahmed Elkharashi, Kinga Grzech-Leśniak, Janina Golob Deeb, Aous A. Abdulmajeed, Sompop Bencharit

General Practice Publications

Background

Removal of cement-retained implant fixed restorations when needed, can be challenging. Conventional methods of crown removal are time consuming and costly for patients and practitioners. This research explored the use of two different types of pulsed erbium lasers as a non-invasive tool to retrieve cemented zirconia crowns from zirconia implant abutments. Materials and methods

Twenty identical zirconia crowns were cemented onto 20 identical zirconia prefabricated abutments using self-adhesive resin cement. The specimens were divided into two groups for laser assisted crown removal; G1 for erbium-doped yttrium aluminum garnet laser (Er:YAG), and G2 for erbium, chromium-doped yttrium, scandium, gallium and …

Effect Of Chemical Treatment On The Physical And Mechanical Properties Of Flax Fibers: A Comparative Assessment, Suhas Yeshwant Nayak, Srinivas Shenoy Heckadka, Aashna Seth, Shrinivasa Prabhu

Open Access archive

In the present study, flax fibers sorted in two batches were considered for treatment. Set one fibers were treated with chemical reagents - KMnO4and acetone for durations of 10, 20 and 30min respectively. The second batch of fibers was treated with stearic acid in ethanol for durations of 24h and 36h. Physical properties namely diameter and density were determined. The treated fibers were also tested to determine their tensile and interfacial adhesion strength. A comparison was drawn between untreated fibers and fibers treated with different treating media. A decrement in the diameter of the fibers with increasing duration of treatment …

Reaction Induced Morphology Changes Of Tetracene And Pentacene Surfaces, Feifei Li, Jacob W. Ciszek

Chemistry: Faculty Publications and Other Works

Morphology plays a critical role in determining the properties of solid-state molecular materials, yet fluctuates wildly as these materials undergo reaction. A prototypical system, a vapor–solid Diels–Alder reaction of tetracene and pentacene thin-films, is used to observe the evolution of morphology features as the reaction transitions from surface to bulk. The initial stages of reaction display little topographical change as measured by atomic force microscopy (AFM) and scanning electron microscopy (SEM), and substrates are coated with a uniform layer of product 1–2 molecules thick, as determined by energy-dispersive X-ray (EDX) spectroscopy. The highly textured surfaces of late stage reactions are …

X-Ray Determination Of Compressive Residual Stresses In Spring Steel Generated By High-Speed Water Quenching, Diego E. Lozano, George E. Totten, Yaneth Bedolla-Gil, Martha Guerrero-Mata, Marcel Carpio, Gabriela M. Martinez-Cazares

Mechanical and Materials Engineering Faculty Publications and Presentations

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core …

Micron-Sized Spinel Crystals In High Level Waste Glass Compositions: Determination Of Crystal Size And Crystal Fraction, C. (Charmayne) E. Lonergan, K. Akinloye-Brown, J. Rice, V. Gervasio, N. Canfield, M. J. Schweiger, J. D. Vienna

Materials Science and Engineering Faculty Research & Creative Works

The compositions utilized for immobilization of high-level nuclear wastes (HLW) are controlled using glass property models to avoid the deleterious effects of crystallization in the high-level waste (HLW) vitrification melters. The type and size of the crystals that precipitate during melter operations (typically at 1150 °C) and idling (∼1000 °C) are significantly impacted by glass composition and thermal history. This study was conducted to measure the impact of melt composition and heat treatment temperature on crystal size and fraction. A matrix of 31 multi-component glasses canvasing the expected Hanford HLW compositional space was developed and the glasses fabricated, and heat …

Using Er:Yag Laser To Remove Lithium Disilicate Crowns From Zirconia Implant Abutments: An In Vitro Study, Janina Golob Deeb, Sompop Bencharit, Nishchal Dalal, Aous Abdulmajeed, Kinga Grzech-Leśniak

Periodontics Publications

Background
When implants are restored with cement-retained restorations, prosthetic retrievability can be difficult and often requires sectioning using rotary instruments. Sometimes repeated removals of a cement-retained implant crown are needed such as for treatment of peri-implantitis or immediate implant provisionalization. The purpose of this study was to evaluate the effect of erbium-doped yttrium aluminum garnet (Er:YAG) laser as a non-invasive treatment modality to remove lithium disilicate crowns from zirconia implant abutments following long-term cementation, repetitive debonding and re-cementation, and short-term retrieval.

Material and methods
Twenty identical lithium disilicate crowns were cemented onto zirconia prefabricated abutments using composite resin cement. Ten …

On The Use Of Vibrational Spectroscopy And Scanning Electron Microscopy To Study Phenolic Extractability Of Cooperage Byproducts In Wine, Berta Baca‑Bocanegra, Julio Nogales‑Bueno, Brian Gorey, Francisco José Heredia, Hugh Byrne, José Miguel Hernández‑Hierro

Articles

Wood is an important source of phenolic compounds, which can be transferred to wine during aging process, improving its properties, from an organoleptic point of view. Therefore, understanding and optimizing the extractability of phenolic compounds from wood are crucial in the oenological field. The structural composition of oak wood samples has been evaluated using Raman and attenuated total reflectance Fourier transform infrared (ATR–FTIR) spectroscopies, and their main spectral features have been linked to phenolic compound extractabilities, as measured by classic chemical analyses. To support the analysis, microscopic images of the samples were also recorded using scanning electron microscopy (SEM). The …

Nanoindentation Characterization On Local Plastic Response Of Ti-6al-4v Under High-Load Spherical Indentation, Yan Wen, Lechun Xie, Zhou Wang, Liqiang Wang, Weijie Lu, Laichang Zhang

Research outputs 2014 to 2021

After high-load spherical indentation treatment, the variations of hardness on the plastic zone of Ti-6Al-4V were investigated via nanoindentation method. The hardness within the center of plastic zone was measured by nanoindenter, and the magnitude decreased gradually along the depth, which were caused by the different extent of plastic deformation under the residual imprint. The microstructure of indentation were observed using scanning electron microscope (SEM) before and after surface etching, and the results showed that the microhardness revealed the average hardness of α and β phases of Ti-6Al-4V. The maximum hardness reached 6.438 GPa in the depth of 132 μm. …

Effect Of Pretreatment Process On Scale Formation In The Re-Boiler Section Of Monoethylene Glycol Regeneration Plant, Ammar Al Helal, Adam Soames, Stefan Iglauer, Ahmed Barifcani, Rolf Gubner

Research outputs 2014 to 2021

Monoethylene glycol (MEG) regeneration plants often use pretreatment vessels to precipitate divalent cations, such as Fe²⁺, Ca²⁺, and Mg²⁺, in order to avoid or reduce fouling in downstream reboilers and heat exchangers. This pretreatment process operates under alkaline conditions and moderate temperatures (~ 80 °C) to accelerate the formation of low-solubility divalent salts. The objective of the present research was to determine whether the pretreatment process could be minimized, without negatively impacts on the MEG regeneration process from to the formation of scale on the heater bundle in the presence of low concentrations of …

Preformed-Particle-Gel Placement And Plugging Performance In Fractures With Tips, Ze Wang, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Preformed-particle gels (PPGs) have been applied for reducing excessive water production caused by fractures in reservoirs. A portion of the fractures existing in reservoirs is composed of a void part and a fracture tip. The PPG placement behavior and plugging performance could be mainly affected by the fracture tips. A fracture with a tip, called a "partially open fracture" in this paper, was designed to investigate the placement and water-plugging performance of PPG. Cylindrical sandstone cores were used to manufacture partially open fractures. Pressure data of PPG injection, post-gel water breakthrough, and stable injection were analyzed to investigate the PPG …

Pollen Evidence Of Medicine From An Embalming Jar Associated With Vittoria Della Rovere, Florence, Italy, Karl Reinhard, Kelsey B. Lynch, Annie Larsen, Braymond Adams, Leon Higley, Marina Milanello Do Amaral, Julia Russ, Donatella Lippi, Johnica J. Morrow, Dario Piombino-Mascali

Karl Reinhard Publications

Various samples of human viscera fragments, sponges, and cloth were collected from embalming jars belonging to members of the Medici family of Florence. One jar was labeled with the name Vittoria della Rovere, who died in March of 1694. This jar contained viscera fragments that were identified as a section of collapsed intestine. The intestine of the Vittoria della Rovere sample contained a large concentration of pollen belonging to the Myrtaceae family. The Myrtaceae pollen was sometimes observed in clusters during analysis, which is indicative of purposeful ingestion of flowers, buds, or a substance derived from floral structures. Thus, the …

Microstructural Changes To Proso Millet Protein Bodies Upon Cooking And Digestion, Paridhi Gulati, You Zhou, Christian Elowsky, Devin J. Rose

Department of Food Science and Technology: Faculty Publications

Cooking results in a drastic decline in digestibility of proso millet proteins, panicins. Scanning electron and confocal microscopy were used to observe morphological changes in proso millet protein bodies upon cooking and digestion that could be associated with the loss in digestibility. Spherical protein bodies (1–2.5 mm) were observed in proso millet flour and extracted protein. Cooking did not result in any noticeable change in the size or shape of the protein bodies. However, upon digestion with pepsin the poor digestibility of cooked proso millet protein was clearly evident from the differences in microstructure of the protein bodies: large cavities …

Enhanced Corrosion Resistance And Cytocompatibility Of Biomimetic Hyaluronic Acid Functionalised Silane Coating On Az31 Mg Alloy For Orthopaedic Applications, Sankalp Vinod Agarwal, Marie Noëlle Labour, David A. Hoey, Brendan Duffy, James Curtin, Swarna Jaiswal

Articles

This paper reports the corrosion resistant and cytocompatible properties of the hyaluronic acid-silane coating on AZ31 Mg alloy. In this study, the osteoinductive properties of high molecular weight hyaluronic acid (HA, 1–4 MDa) and the corrosion protection of silane coatings were incorporated as a composite coating on biodegradable AZ31 Mg alloy for orthopaedic applications. The multi-step fabrication of coatings first involved dip coating of a passivated AZ31 Mg alloy with a methyltriethoxysilane-tetraethoxysilane sol-gel to deposit a dense, cross-linked and corrosion resistant silane coating (AZ31-MT). The second step was to create an amine-functionalised surface by treating coated alloy with 3-aminopropyl-triethoxy silane …

Thermal Conductivity Performance Of Polypropylene Composites Filled With Polydopamine-Functionalized Hexagonal Boron Nitride, Lin Chen, Hong-Fei Xu, Shao-Jian He, Yi-Hang Du, Nan-Jie Yu, Jun Lin, Sergei I. Nazarenko

Faculty Publications

Mussel-inspired approach was attempted to non-covalently functionalize the surfaces of boron nitride (BN) with self-polymerized dopamine coatings in order to reduce the interfacial thermal barrier and enhance the thermal conductivity of BN-containing composites. Compared to the polypropylene (PP) composites filled with pristine BN at the same filler content, thermal conductivity was much higher for those filled with both functionalized BN (f-BN) and maleic anhydride grafted PP (PP-g-ma) due to the improved filler dispersion and better interfacial filler-matrix compatibility, which facilitated the development of more thermal paths. Theoretical models were also applied to predict the composite thermal conductivity in which the …

Biochemical And Histological Differences Between Costal And Articular Cartilages, Michael W. Stacey

Bioelectrics Publications

Biologically, costal cartilage is an understudied tissue type and much is yet to be learned regarding underlying mechanisms related to form and function, and how these relate to disease states, specifically chest wall deformity. Chest wall deformities have a component of inheritance, implying underlying genetic causes; however the complexity of inheritance suggests multiple genetic components. At our Centre investigations were performed on gene expression of key select genes from costal cartilage removed at surgery of patients with chest wall deformity to show high expression of decorin, a key player in collagen fiber formation and growth. Also, the degree of tissue …

Direct Imaging Of Coexisting Ordered And Frustrated Sublattices In Artificial Ferromagnetic Quasicrystals, Barry Farmer, Vinayak Shantaram Bhat, Eric Teipel, J. Unguris, D. J. Keavney, Jeffrey Todd Hastings, Lance E. De Long

Physics and Astronomy Faculty Publications

We have used scanning electron microscopy with polarization analysis and photoemission electron microscopy to image the two-dimensional magnetization of permalloy films patterned into Penrose P2 tilings (P2T). The interplay of exchange interactions in asymmetrically coordinated vertices and short-range dipole interactions among connected film segments stabilize magnetically ordered, spatially distinct sublattices that coexist with frustrated sublattices at room temperature. Numerical simulations that include long-range dipole interactions between sublattices agree with images of as-grown P2T samples and predict a magnetically ordered ground state for a two-dimensional quasicrystal lattice of classical Ising spins.

Weak Magnetic Field Accelerates Chromate Removal By Zero-Valent Iron, Pian Feng, Xiaohong Guan, Yuankui Sun, Wonyong Choi, Hejie Qin, Jianmin Wang, Junlian Qiao, Lina Li

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Weak magnetic field (WMF) was employed to improve the removal of Cr(VI) by zero-valent iron (ZVI) for the first time. The removal rate of Cr(VI) was elevated by a factor of 1.12-5.89 due to the application of a WMF, and the WMF-induced improvement was more remarkable at higher Cr(VI) concentration and higher pH. Fe2+ was not detected until Cr(VI) was exhausted, and there was a positive correlation between the WMF-induced promotion factor of Cr(VI) removal rate and that of Fe²⁺ release rate in the absence of Cr(VI) at pH 4.0-5.5. These phenomena imply that ZVI corrosion with Fe^{2+ …}

Impact Of Symmetry On The Ferroelectric Properties Of Catio₃ Thin Films, Michael D. Biegalski, Liang Qiao, Yijia Gu, Apurva Mehta, Qian He, For Full List Of Authors, See Publisher's Website.

Materials Science and Engineering Faculty Research & Creative Works

Epitaxial strain is a powerful tool to induce functional properties such as ferroelectricity in thin films of materials that do not possess ferroelectricity in bulk form. In this work, a ferroelectric state was stabilized in thin films of the incipient ferroelectric, CaTiO₃, through the careful control of the biaxial strain state and TiO₆ octahedral rotations. Detailed structural characterization was carried out by synchrotron x-ray diffraction and scanning transmission electron microscopy. CaTiO₃ films grown on La_0.18Sr_0.82Al_0.59Ta_0.41O₃ (LSAT) and NdGaO₃ (NGO) substrates experienced a 1.1% biaxial strain state …

Properties Of Cu(In,Ga,Al)Se² Thin Films Fabricated By Magnetron Sputtering, Talaat A. Hameed, Wei Cao, Bahiga A. Mansour, Inas K. Elzawaway, El-Metwally M. Abdelrazek, Hani E. Elsayed-Ali

Applied Research Center Publications

Cu (In,Ga,Al)Se₂ (CIGAS) thin films were studied as an alternative absorber layer material to Cu(In_xGa_1-x)Se₂. CIGAS thin films with varying Al content were prepared by magnetron sputtering on Si(100) and soda-lime glass substrates at 350 °C, followed by postdeposition annealing at 520 °C for 5 h in vacuum. The film composition was measured by an electron probe microanalyzer while the elemental depth profiles were determined by secondary ion mass spectrometry. X-ray diffraction studies indicated that CIGAS films are single phase with chalcopyrite structure and that the (112) peak clearly shifts to higher 2θ …

Morphology And Ploidy Level Determination Of Pteris Vittata Callus During Induction And Regeneration, Blake L. Joyce, Shigetoshi Eda, John Dunlap, Neal Stewart

Plant Sciences Publications and Other Works

Background: Morphological and ploidy changes of the arsenic hyperaccumulator, Chinese brake fern (Pteris vittata) callus tissue are described here to provide insight into fern life cycle biology and for possible biotechnology applications. Pteris vittata callus was studied using transmission and scanning electron microscopy, and flow cytometry.

Results: Callus induction occurred both in light and dark culture conditions from prothallus tissues, whereas rhizoid formation occurred only in dark culture conditions. Callus tissues contained two types of cells: one actively dividing and the other containing a single large vacuole undergoing exocytosis. Sporophytes regenerated from callus asynchronously form clusters of cells …

Role Of Type Iv Pili In Predation By Bdellovibrio Bacteriovorus, Ryan M Chanyi, Susan F Koval

Microbiology & Immunology Publications

Bdellovibrio bacteriovorus, as an obligate predator of Gram-negative bacteria, requires contact with the surface of a prey cell in order to initiate the life cycle. After attachment, the predator penetrates the prey cell outer membrane and enters the periplasmic space. Attack phase cells of B. bacteriovorus have polar Type IV pili that are required for predation. In other bacteria, these pili have the ability to extend and retract via the PilT protein. B. bacteriovorus has two pilT genes, pilT1 and pilT2, that have been implicated in the invasion process. Markerless in-frame deletion mutants were constructed in a prey-independent mutant to …