69 research outputs found
High aspect ratio template and method for producing same for central and peripheral nerve repair
Millimeter to nano-scale structures manufactured using a multi-component polymer fiber matrix are disclosed. The use of dissimilar polymers allows the selective dissolution of the polymers at various stages of the manufacturing process. In one application, biocompatible matrixes may be formed with long pore length and small pore size. The manufacturing process begins with a first polymer fiber arranged in a matrix formed by a second polymer fiber. End caps may be attached to provide structural support and the polymer fiber matrix selectively dissolved away leaving only the long polymer fibers. These may be exposed to another product, such as a biocompatible gel to form a biocompatible matrix. The polymer fibers may then be selectively dissolved leaving only a biocompatible gel scaffold with the pores formed by the dissolved polymer fibers. The scaffolds may be used in, among other applications, the repair of central and peripheral nerves. Scaffolds for the repair of peripheral nerves may include a reservoir for the sustained release of nerve growth factor. The scaffolds may also include a multifunctional polyelectrolyte layer for the sustained release of nerve growth factor and enhance biocompatibility
System and method for suppressing sublimation using opacified aerogel
The present invention relates to a castable, aerogel-based, ultra-low thermal conductivity opacified insulation to suppress sublimation. More specifically, the present invention relates to an aerogel opacified with various opacifying or reflecting constituents to suppress sublimation and provide thermal insulation in thermoelectric modules. The opacifying constituent can be graded within the aerogel for increased sublimation suppression, and the density of the aerogel can similarly be graded to achieve optimal thermal insulation and sublimation suppression
Mg/O<sub>2</sub> Battery Based on the Magnesium-Aluminum Chloride Complex (MACC) Electrolyte
Mg/O<sub>2</sub> cells employing
a MgCl<sub>2</sub>/AlCl<sub>3</sub>/DME (MACC/DME) electrolyte are
cycled and compared to cells with
modified Grignard electrolytes, showing that performance of magnesium/oxygen
batteries depends strongly on electrolyte composition. Discharge capacity
is far greater for MACC/DME-based cells, while rechargeability in
these systems is severely limited. The Mg/O<sub>2</sub>-MACC/DME discharge
product comprises a mixture of Mg(ClO<sub>4</sub>)<sub>2</sub> and
MgCl<sub>2</sub>, with the latter likely formed from slow decomposition
of the former. The presence of Cl in these compounds suggests that
the electrolyte participates in the cell reaction or reacts readily
with the initial electrochemical products. A rate study suggests that
O<sub>2</sub> diffusion in the electrolyte limits discharge capacities
at higher currents. Formation of an insulating product film on the
positive electrodes of Mg/O<sub>2</sub>-MACC/DME cells following deep
discharge increases cell impedance substantially and likely explains
the poor rechargeability. An additional impedance rise consistent
with film formation on the Mg negative electrode suggests the presence
of detrimental O<sub>2</sub> crossover. Minimizing O<sub>2</sub> crossover
and bypassing charge transfer through the discharge product would
improve battery performance
Peripheral nerve growth within a hydrogel microchannel scaffold supported by a kink‐resistant conduit
Nerve repair in several mm‐long nerve gaps often requires an interventional technology. Microchannel scaffolds have proven effective for bridging nerve gaps and guiding axons in the peripheral nervous system (PNS). Nonetheless, fabricating microchannel scaffolds at this length scale remains a challenge and/or is time consuming and cumbersome. In this work, a simple computer‐aided microdrilling technique was used to fabricate 10 mm‐long agarose scaffolds consisting of 300 µm‐microchannels and 85 µm‐thick walls in less than an hour. The agarose scaffolds alone, however, did not exhibit adequate stiffness and integrity to withstand the mechanical stresses during implantation and suturing. To provide mechanical support and enable suturing, poly caprolactone (PCL) conduits were fabricated and agarose scaffolds were placed inside. A modified salt‐leaching technique was developed to introduce interconnected porosity in PCL conduits to allow for tuning of the mechanical properties such as elastic modulus and strain to failure. It was shown that the PCL conduits were effective in stabilizing the agarose scaffolds in 10 mm‐long sciatic nerve gaps of rats for at least 8 weeks. Robust axon ingress and Schwann cell penetration were observed within the microchannel scaffolds without using growth factors. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3392–3399, 2017.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139110/1/jbma36186_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139110/2/jbma36186.pd
Oxide‐Based Solid‐State Batteries: A Perspective on Composite Cathode Architecture
The garnet-type phase LiLaZrO (LLZO) attracts significant attention as an oxide solid electrolyte to enable safe and robust solid-state batteries (SSBs) with potentially high energy density. However, while significant progress has been made in demonstrating compatibility with Li metal, integrating LLZO into composite cathodes remains a challenge. The current perspective focuses on the critical issues that need to be addressed to achieve the ultimate goal of an all-solid-state LLZO-based battery that delivers safety, durability, and pack-level performance characteristics that are unobtainable with state-of-the-art Li-ion batteries. This perspective complements existing reviews of solid/solid interfaces with more emphasis on understanding numerous homo- and heteroionic interfaces in a pure oxide-based SSB and the various phenomena that accompany the evolution of the chemical, electrochemical, structural, morphological, and mechanical properties of those interfaces during processing and operation. Finally, the insights gained from a comprehensive literature survey of LLZO–cathode interfaces are used to guide efforts for the development of LLZO-based SSBs
Expression analysis of genes associated with human osteosarcoma tumors shows correlation of RUNX2 overexpression with poor response to chemotherapy
Background: Human osteosarcoma is the most common pediatric bone tumor. There is limited understanding of the molecular mechanisms underlying osteosarcoma oncogenesis, and a lack of good diagnostic as well as prognostic clinical markers for this disease. Recent discoveries have highlighted a potential role of a number of genes including: RECQL4, DOCK5, SPP1, RUNX2, RB1, CDKN1A, P53, IBSP, LSAMP, MYC, TNFRSF1B, BMP2, HISTH2BE, FOS, CCNB1, and CDC5L. Methods: Our objective was to assess relative expression levels of these 16 genes as potential biomarkers of osteosarcoma oncogenesis and chemotherapy response in human tumors. We performed quantitative expression analysis in a panel of 22 human osteosarcoma tumors with differential response to chemotherapy, and 5 normal human osteoblasts.Results: RECQL4, SPP1, RUNX2, and IBSP were significantly overexpressed, and DOCK5, CDKN1A, RB1, P53, and LSAMP showed significant loss of expression relative to normal osteoblasts. In addition to being overexpressed in osteosarcoma tumor samples relative to normal osteoblasts, RUNX2 was the only gene of the 16 to show significant overexpression in tumors that had a poor response to chemotherapy relative to good responders. Conclusion: These data underscore the loss of tumor suppressive pathways and activation of specific oncogenic mechanisms associated with osteosarcoma oncogenesis, while drawing attention to the role of RUNX2 expression as a potential biomarker of chemotherapy failure in osteosarcoma. © 2010 Sadikovic et al; licensee BioMed Central Ltd
2019 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations
The International Liaison Committee on Resuscitation has initiated a continuous review of new, peer-reviewed, published cardiopulmonary resuscitation science. This is the third annual summary of the International Liaison Committee on Resuscitation International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. It addresses the most recent published resuscitation evidence reviewed by International Liaison Committee on Resuscitation Task Force science experts. This summary addresses the role of cardiac arrest centers and dispatcher-assisted cardiopulmonary resuscitation, the role of extracorporeal cardiopulmonary resuscitation in adults and children, vasopressors in adults, advanced airway interventions in adults and children, targeted temperature management in children after cardiac arrest, initial oxygen concentration during resuscitation of newborns, and interventions for presyncope by first aid providers. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the certainty of the evidence on the basis of the Grading of Recommendations, Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations. Insights into the deliberations of the task forces are provided in the Justification and Evidence to Decision Framework Highlights sections. The task forces also listed priority knowledge gaps for further research
Mechanical properties of NaSICON: a brief review
A variety of rechargeable Na batteries are under development for use in energy storage systems. For these batteries, a Na-ion conducting solid electrolyte is desired. One such electrolyte under consideration is NaSICON (Na Super Ionic Conductor). One important aspect of the NaSICON electrolytes that has been overlooked is their mechanical properties. Such information is required if NaSICON has to be used as a solid electrolyte in rechargeable Na batteries that exhibit long life cycle and high power. This paper reviews the elastic, plastic, and fracture properties of NaSICON electrolytes. Young's modulus values for NaSICON range from similar to 56 to 97 GPa with Poisson's ratio similar to 0.26. Hardness values determined by micro-indentation for NaSiCON are 4.4-4.9 GPa. The value of the Gilman-Chin parameter suggests the bonding in NaSICON is covalent. As a result of its covalent bonding, NaSICON exhibits a high Peierls which leads to low fracture toughness, with K-IC values similar to 1-1.5 MPa m(0.)(5). The fracture strength of NaSICON is between 50 and 110 MPa and is controlled by the amount and size of the second-phase ZrO2 particles
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