Contributors:Yu-I Shen, Hyun-Ho G. Song, Arianne E. Papa, Jacqueline A. Burke, Susan W. Volk, Sharon Gerecht
Currently available skin grafts and skin substitutes for healing following third-degree burn injuries are fraught with complications, often resulting in long-term physical and psychological sequelae. Synthetic treatment that can promote wound healing in a regenerative manner would provide an off-the-shelf, non-immunogenic strategy to improve clinical care of severe burn wounds. Here, we demonstrate the vulnerary efficacy and accelerated healing mechanism of a dextran-based hydrogel in a third-degree porcine burn model. The model was optimized to allow examination of the hydrogel treatment for clinical translation and its regenerative response mechanisms. Hydrogel treatment accelerated third-degree burn wound healing by rapid wound closure, improved re-epithelialization, enhanced extracellular matrix remodeling, and greater nerve reinnervation, compared with the dressing-treated group. These effects appear to be mediated through the ability of the hydrogel to facilitate a rapid but brief initial inflammatory response that coherently stimulates neovascularization within the granulation tissue during the first week of treatment, followed by an efficient vascular regression to promote a regenerative healing process. Our results suggest that the dextran-based hydrogels may substantially improve healing quality and reduce skin grafting incidents and thus pave the way for clinical studies to improve the care of severe burn injury patients.
Contributors:Ajay Malhotra, Xiao Wu, Vivek B. Kalra, Thomas R. Goodman, Joseph Schindler, Howard P. Forman
Timely and accurate screening for pediatric blunt cerebrovascular injury (BCVI) is important in order to administer appropriate anticoagulation therapy thus preventing stroke. The recommended criteria for screening in children are not clear. We performed a systematic review of the literature for screening and management of BCVI in children and designed a cost-effectiveness analysis in order to determine the optimal strategy for managing pediatric BCVI from a societal perspective.
Contributors:Christine L. Monteleon, Andrew McNeal, Elizabeth K. Duperret, Seung J. Oh, Emily Schapira, Todd W. Ridky
IQ motif–containing GTPase-activating protein (IQGAP) scaffolding proteins regulate many essential cellular processes including growth factor receptor signaling, cytoskeletal rearrangement, adhesion, and proliferation and are highly expressed in many cancers. Using genetically engineered human skin tissue in vivo, we demonstrate that diminished, sub-physiologic expression of IQGAP1 or IQGAP3 is sufficient to maintain normal epidermal homeostasis, whereas significantly higher levels are required to support tumorigenesis. To target this tumor-specific IQGAP requirement in vivo, we engineered epidermal keratinocytes to express individual IQGAP protein domains designed to compete with endogenous IQGAPs for effector protein binding. Expression of the IQGAP1-IQ motif decoy domain in epidermal tissue in vivo inhibits oncogenic Ras-driven mitogen-activated protein kinase signaling and antagonizes tumorigenesis, without disrupting normal epidermal proliferation or differentiation. These findings define essential non-redundant roles for IQGAP1 and IQGAP3 in the epidermis and demonstrate the potential of IQGAP antagonism for cancer therapy.
NO3 radical-initiated atmospheric degradation of p,p′-dichloro-diphenyl-dichloro-ethylene (p,p′-DDE) is anticipated as a significant removal pathway at night. Detailed oxidation processes have been studied using density functional molecular orbital theory. Geometrical optimizations of reactants, intermediates, transition states, and products were operated at the MPWB1K/6-31+G(d,p) level. Single-point energy calculations were performed at the MPWB1K/6-311+G(3df,2p) level. Theoretical results indicate that NO3 radicals tend to bond greater to C atoms of a CC double bond than to a benzene ring. In the presence of O2 and NOx, the main ingredients of complete degradation products of DDE–NO3 adducts are 4,4′-dichlorobenzophenone and phosgene. Rate constants of NO3 addition reactions are calculated by employing MESMER program at an adequate atmospheric temperature range of 200–400K. Specifically, the total rate constant of NO3-addition reactions is 2.13×10−13cm3molecule−1s−1 at 298K and 760Torr. This research provides a thorough understanding of the reaction mechanism involved in NO3-initiated atmospheric degradation of p,p′-DDE and may set as a relevant supplemental reference criteria for experimental research.
Electronic and structural properties of two conformations including conjugated compounds of fluorene 1,3,4 thiadiazole and the electron acceptor [6,6]-phenyl C61-butyric acid methyl ester or PCBM, (PCBM/TDA10FL) were calculated using density functional theory (DFT) to assess their possible application as organic semiconductor materials in photovoltaic devices. The studied conformations show some appropriate properties to be used in solar cells, as a maximum absorption wavelength within the maximum solar spectrum, but the band gap is not the adequate, showing values over 4eV. The donor behavior expected for the TDA oligomer changes to electron acceptor as shown the HOMO and LUMO density energy distribution. This led to the study of a third conjugated polymer using poly 3-hexylthiophene as a donor, trying to prove the electro acceptor character shown by fluorene-1,3,4 thiadiazole. Results for the third conformation show a gap energy value and an absorption wavelength, which are suitable for bulk heterojunction solar cells, and the distribution of the HOMO and LUMO indicate that the TDA oligomer chain maintains an electron acceptor behavior.
In the present study, a numerical prediction method on the hydrodynamic interaction force and moment between two ships in shallow and restricted waterway is presented. Especially, the present study proposes a methodology to overcome the limitation of the two dimensional perturbation method which is related to the moored-passing ship interaction. The validation study was performed and compared with the experiment, firstly. Afterward, in order to propose a methodology in terms with the moored-passing ship interaction, further studies were performed for the moored-passing ship case with a Reynolds Averaged Navier-Stokes (RANS) calculation which is using OpenFOAM with Arbitrary Coupled Mesh Interface (ACMI) technique and compared with the experiment result. Finally, the present study proposes a guide to apply the two dimensional perturbation method to the moored-passing ship interaction. In addition, it presents a possibility that the RANS calculation with ACMI can applied to the ship-ship interaction without using a overset moving grid technique.
Contributors:Jung-Kyu Choi, Byoung-Kwon Ahn, Hyoung-Tae Kim
For Super-Cavitating Underwater Vehicles (SCUV), the numerical analyses and experiments in a large cavitation tunnel are carried out at relatively large Reynolds numbers. The numerical results agree well with experiments and the drag coefficient of SCUV is rarely changed by the Reynolds number. As the cavitation number is decreased, the cavity occurs and grows, the cavitator drag decreases and the body drag is affected by the degree of covering the body with the cavity. The tunnel effects, i.e. the blockage and the friction pressure drop of the tunnel, on the drag and the cavitation of SCUV are examined from the numerical results in between the tunnel and unbounded flows. In the tunnel, a minimum cavitation number exists and the drag of SCUV appears larger than that in unbounded flow. When the super-cavity covers the entire body, the friction drag almost disappears and the total drag of SCUV can be regarded as the pressure drag of cavitator
Contributors:Sung-Wook Kang, Yong-Man Park, Beom-Seon Jang, Yu-Chul Jeon, Seong-Min Kim
Although the transverse butt weld method with ceramic backing strip has been widely used in various industrial fields for its fabricational convenience, it is rarely used in offshore industries since the fatigue strength of the weld joint has not been proved sufficiently. This study conducted fatigue tests for series of butt weld specimens with horizontal (2G) and vertical (3G) welding positions in order to verify the fatigue strength compared to S-N curve by DNV (Det Norske Veritas), IIW (International Institute of Welding) and Eurocode 3. The difference of the 2G specimens and the 3G specimens are investigated in terms of angular distortion and the effect on the fatigue strength are analyzed.
Contributors:Morten Egevang Jørgensen, Hussam Hassan Nour-Eldin, Barbara Ann Halkier
Plants synthesize a plethora of defense compounds crucial for their survival in a challenging and changing environment. Transport processes are important for shaping the distribution pattern of defense compounds, albeit focus hitherto has been mostly on their biosynthetic pathways. A recent identification of two glucosinolate transporters represents a breakthrough in our understanding of glucosinolate transport in Arabidopsis and has advanced knowledge in transport of defense compounds. In this review, we discuss the role of the glucosinolate transporters in establishing dynamic glucosinolate distribution patterns and source–sink relations. We focus on lessons learned from glucosinolate transport that may apply to transport of other defense compounds and discuss future avenues in the emerging field of defense compound transport.