Accelerating Taub-NUT and Eguchi-Hanson solitons in four dimensions

We construct new solutions of the vacuum Einstein field equations in four dimensions via a solution generating method utilizing the SL(2,R) symmetry of the reduced Lagrangian. We apply the method to an accelerating version of the Zipoy-Voorhees solution and generate new solutions which we interpret to be the accelerating versions of the Zipoy-Voorhees generalisation of the Taub-NUT solution (with Lorentzian signature) and the Zipoy-Voorhees generalisation of the Eguchi-Hanson solitons (with Euclidean signature). As an intermediary in the solution-generating process we obtain charged versions of the accelerated Zipoy-Voorhees-like families of solutions. Finally we present the accelerating version of the Taub-NUT solution and discuss its properties.Comment: 16 page

Hydrogels in Stereolithography

The use of stereolithography (SL) for fabricating complex three-dimensional (3D) tissue engineered scaffolds of aqueous poly(ethylene glycol) (PEG) hydrogel solutions is described. The primary polymer used in the study was PEG-dimethacrylate (PEG-dma) with an average molecular weight (MW) of 1000 in distilled water with the photoinitiator Irgacure 2959 (I-2959). Successful layered manufacturing (LM) with embedded channel architecture required investigation of the photopolymerization characteristics of the PEG solution (measured as hydrogel thickness or cure depth) as a function of photoinitiator concentration and laser energy dosage for a specific photoinitiator type and polymer concentration in solution. Hydrogel thickness was a strong function of PI concentration and energy dosage. Curves of hydrogel thickness were utilized to successfully plan, perform, and demonstrate layered manufacturing of highly complex hydrogel scaffold structures, including structures with internal channels of various orientations. Successful fabrication of 3D, multi-layered bioactive PEG scaffolds containing cells was accomplished using a slightly modified commercial SL system (with 325 nm wavelength laser) and procedure. Human dermal fibroblast (HDF) cells were encapsulated in PEG hydrogels using small concentrations (~ 5 mg/ml) of acryloyl-PEG-RGDS (MW 3400) added to the photopolymerizable PEG solution to promote cell attachment. HDF cells were combined with the PEG solution, photocrosslinked using SL, and successfully shown to survive the fabrication process. The combined use of SL and photocrosslinkable biomaterials such as PEG makes it possible to fabricate complex 3D scaffolds that provide site-specific and tailored mechanical properties (i.e., multiple polymer materials) with a polymer matrix that allows transport of nutrients and waste at the macroscale and facilitates cellular processes at the microscale through precisely placed bioactive agents.Mechanical Engineerin

Multi-Material Stereolithography: Spatially-Controlled Bioactive Poly(Ethylene Glycol) Scaffolds for Tissue Engineering

Challenges remain in tissue engineering to control the spatial and temporal mechanical and biochemical architectures of scaffolds. Unique capabilities of stereolithography (SL) for fabricating multi-material spatially-controlled bioactive scaffolds were explored in this work. To accomplish multi-material builds with implantable materials, a new mini-vat setup was designed, constructed and placed on top of the existing build platform to allow for accurate and selfaligning X-Y registration during fabrication. Precise quantities of photocrosslinkable solution were added to and removed from the mini-vat using micro-pipettes. The mini-vat setup allowed the part to be easily removed and rinsed and different photocrosslinkable solutions could be easily removed and added to the vat to aid in multi-material fabrication. Two photocrosslinkable hydrogel biopolymers, poly(ethylene glycol dimethacrylate) (PEG-dma, molecular wt 1,000) and poly(ethylene glycol)-diacrylate (PEG-da, molecular wt 3,400), were used as the primary scaffold materials, and controlled concentrations of fluorescently labeled dextran or bioactive PEG were prescribed and fabricated in different regions of the scaffold using SL. The equilibrium swelling behavior of the two biopolymers after SL fabrication was determined and used to design constructs with the specified dimensions at the swollen state. Two methods were used to measure the spatial gradients enabled by this process with multi-material spatial control successfully demonstrated down to 500-µm. First, the presence of the fluorescent component in specific regions of the scaffold was analyzed with fluorescent microscopy. Second, human dermal fibroblast cells were seeded on top of the fabricated scaffolds with selective bioactivity, and phase contrast microscopy images were used to show specific localization of cells in the regions patterned with bioactive PEG. The use of multi-material SL and the relative ease of conjugating different bioactive ligands or growth factors to PEG allows for the fabrication of tailored three-dimensional constructs with specified spatially-controlled bioactivity.Mechanical Engineerin

University Chorale and Women\u27s Choir, Behold, How Good

Under the direction of Dr. Alison Mann, University Chorale and Women\u27s Choir present a program titled Behold, How Good, featuring sacred and secular works from a wide variety of composers and arrangers in the choral music repertoire.https://digitalcommons.kennesaw.edu/musicprograms/1010/thumbnail.jp

University Chorale and Women\u27s Choir, Threaded with Stars

University Chorale and Women\u27s Choir perform a special program titled Threaded with Stars featuring a variety of choral works ranging from well-loved sacred and secular works to new, contemporary pieces and arrangements.https://digitalcommons.kennesaw.edu/musicprograms/1053/thumbnail.jp

Efficacy of a crosslinked hyaluronic acid-based hydrogel as a tear film supplement: a masked controlled study.

This is the final publish manuscript distributed under a Creative Commons Attribution License 2.0 UK, which can also be found on the publisher's website at: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0099766Keratoconjunctivitis sicca (KCS), or dry eye, is a significant medical problem in both humans and dogs. Treating KCS often requires the daily application of more than one type of eye drop in order to both stimulate tear prodcution and provide a tear supplement to increase hydration and lubrication. A previous study demonstrated the potential for a crosslinked hyaluronic acid-based hydrogel (xCMHA-S) to reduce the clinical signs associated with KCS in dogs while using a reduced dosing regimen of only twice-daily administration. The present study extended those results by comparing the use of the xCMHA-S to a standard HA-containing tear supplement in a masked, randomized clinical study in dogs with a clinical diagnosis of KCS. The xCMHA-S was found to significantly improve ocular surface health (conjunctival hyperaemia, ocular irritation, and ocular discharge) to a greater degree than the alternative tear supplement (P = 0.0003). Further, owners reported the xCMHA-S treatment as being more highly effective than the alternative tear supplement (P = 0.0024). These results further demonstrate the efficacy of the xCMHA-S in reducing the clinical signs associated with KCS, thereby improving patient health and owner happiness

Charging Black Saturn?

We construct new charged static solutions of the Einstein-Maxwell field equations in five dimensions via a solution generation technique utilizing the symmetries of the reduced Lagrangian. By applying our method on the multi-Reissner-Nordstrom solution in four dimensions, we generate the multi-Reissner-Nordstrom solution in five dimensions. We focus on the five-dimensional solution describing a pair of charged black objects with general masses and electric charges. This solution includes the double Reissner-Nordstrom solution as well as the charged version of the five-dimensional static black Saturn. However, all the black Saturn configurations that we could find present either a conical singularity or a naked singularity. We also obtain a non-extremal configuration of charged black strings that reduces in the extremal limit to a Majumdar-Papapetrou like solution in five dimensions.Comment: 27 pages, 3 figures, v.3 added more references, corrected typo

Spring Concert Choral Ensembles

Join us (virtually) for an evening of performances by Women\u27s Choir, Men\u27s Ensemble, and University Chorale!https://digitalcommons.kennesaw.edu/musicprograms/2382/thumbnail.jp

KSU Choral Ensembles Fall Concert

The combined choral ensemble area presents their 2019 fall concert.https://digitalcommons.kennesaw.edu/musicprograms/2255/thumbnail.jp