ASSESSING EAR PINNA REPAIR IN THE MRL/MpJ MOUSE STRAIN

The outcome of tissue repair varies across species. Vertebrates such as salamanders have the ability to not only heal scar-free but also completely regenerate lost appendages. In contrast, most mammals heal their wounds with fibrotic scarring. Understanding the key drivers of these divergent injury responses remains a major unanswered question in animal biology. Previous work with the Murphy’s Roth Large (MRL/MpJ) inbred mouse strain suggested they have the ability to rapidly close small (2mm) ear holes. While this ability was originally published as an example of regeneration, subsequent work by other groups suggested that it might represent something more akin to hyper-fibrosis. Thus, the ability of MRL/MpJ mice to heal ear hole punches by regeneration or via fibrotic repair (scarring) remains unresolved. The purpose of this study was to analyze ear hole closure in the MRL/MpJ strain across a range of hole sizes and to characterize the healing process. Moreover, I tested multiple hypotheses that could explain the rapid closure of small ear holes, including MRL/MpJ mice exhibit enhanced cell proliferation, increased ECM gene expression, synthesis, and deposition, and that they exhibit hyperinflammation compared to control outbred strains. We found marginal, albeit weak, support for all three hypotheses supporting faster closure of ear punch injuries but did not find evidence of tissue regeneration

Near-Infrared Fluorescent Carbon Nanotubes; A New Paradigm in Disease Detection and Biological Imaging

The bandgap near-infrared photoluminescence from the semiconducting single-walled carbon nanotubes is photostable, tunable, and sensitive to the local environment. Over the last 15 years, significant progress has been made in applying carbon nanotube photoluminescence toward a range of in vitro and in vivo biomedical applications. My research at URI NanoBio Engineering Lab encompasses the design and implementation of implantable and wearable biosensors in addition to developing in vitro molecular probes, based on single-walled carbon nanotubes. We engineer the molecular corona of the SWCNTs to significantly enhance their selectivity to multiple disease biomarkers, so their spectral variations can be utilized for biomarker detection and quantification, down to nanomolar concentrations. We then embed these nanomaterials into biocompatible scaffolds to provide implantable and wearable sensing platforms. We also utilize a variety of imaging, spectroscopy, and other analytical techniques to investigate the fundamental interactions between our engineered nanomaterials and biological systems. Using a specialized near-infrared fluorescence hyperspectral imaging system, we are able to collect the emission spectra from single carbon nanotubes within live cells. By fully characterizing these types of nanobio interactions, we aim to construct highly robust bio-analytical probes while simultaneously mitigating toxicological concerns

MAGNETIC FIELD-ASSISTED MANUFACTURING OF FUNCTIONAL POLYMERIC COMPOSITES

Magnetic polymeric composites have recently found their way into creating functional products that respond to an external stimulus while accomplishing complex tasks. A common manufacturing method for these materials is magnetic field-assisted manufacturing, where an external field is used during or after creating the product to induce local or global particle patterns or magnetization profiles. As one of the processes paired with magnetic field, additive manufacturing (AM) has shown great potential in developing complex structures with local control over material properties. In this work, using magneto-responsive reinforcing fibers and different polymeric matrices, we explore the potential of this process in creating functional polymeric composites and find applications for the resulting products.First, a design, manufacturing, and characterization framework for creating functional magnetic composites is developed. The potential of pairing magnetic field with AM in creating functionally graded polymeric composites with controlled local fiber orientation and concentration is studied. Composite materials fabricated and characterized to understand the relationships between process parameters, particle distribution, and local mechanical properties. Two simple characterization frameworks are developed to correlate the particle distribution and local properties of manufactured polymeric composites, and replace more expensive and complex methods.Next, two photocurable resin systems for the magnetic field-assisted AM are proposed and verified. Due to the molecular and capillary forces in bottom-up vat photopolymerization, it is challenging to control the particle distribution during the manufacturing process. Here we use surface treatment of magnetic particles to create temporary bonding between the particles and resin systems. Using this method enables a better control over particle distribution during the manufacturing process and prevents the particle aggregation. It is also proved that treated particles in resin systems can ensure more predictable curing behavior and better mechanical properties in the final photocured polymeric composites.Finally, we explore the potential magnetic field-assisted manufacturing in introducing desired magnetization profiles into polymeric composites. In this section, magnetoelastic structures are fabricated and studied to understand their behavior under dynamic magnetic fields. Using the proposed design for the magnetoelastic composites, untethered multimodal control over soft magnetic robots is achieved

Nondegeneracy of the spectrum of the twisted cocycle for interval exchange transformations

We prove the positivity of the top Lyapunov exponent of the twisted (spectral) cocycle, associated with IETs, with respect to a family of natural invariant measures. The proof relies on relating the top exponent to limits of exponents along families of affine invariant submanifolds of genus tending to infinity. Applications include an observation about a conjecture of Kontsevich and Zorich, a discrepancy estimate, and a formula for the lower local dimension of spectral measures

Management of Noncatastrophic Internal Carotid Artery Injury in Endoscopic Skull Base Surgery.

Arterial injuries are the most feared complication of endoscopic skull base surgery. During resection of the middle fossa component of a large ventral skull base chondrosarcoma, arterial bleeding was encountered near the right internal carotid artery (ICA). Durable hemostasis could not be achieved with packing and the patient was taken for an emergent angiogram that revealed a pseudoaneurysm of the proximal intradural ICA. Given the presence of good collateral flow through the anterior and posterior communicating arteries, the right ICA was sacrificed by coil embolization. The patient was taken back to the operating room for closure then transferred to the intensive care unit and maintained on vasopressors for five days to ensure adequate perfusion. The right ICA was coil embolized and the patient was taken back to the operating room for closure. The patient recovered without complication. Arterial injuries, although serious, are not always catastrophic. Critical steps are immediate recognition of bleeding, vascular imaging, and vessel sacrifice if necessary

Impact of Human Immunodeficiency Virus in the Pathogenesis and Outcome of Patients with Glioblastoma Multiforme.

BackgroundImprovement in antiviral therapies have been accompanied by an increased frequency of non-Acquired Immune Deficiency Syndrome (AIDS) defining malignancies, such as glioblastoma multiforme. Here, we investigated all reported cases of human immunodeficiency virus (HIV)-positive patients with glioblastoma and evaluated their clinical outcomes. A comprehensive review of the molecular pathogenetic mechanisms underlying glioblastoma development in the setting of HIV/AIDS is provided.MethodsWe performed a PubMed search using keywords "HIV glioma" AND "glioblastoma," and "AIDS glioma" AND "glioblastoma." Case reports and series describing HIV-positive patients with glioblastoma (histologically-proven World Health Organization grade IV astrocytoma) and reporting on HAART treatment status, clinical follow-up, and overall survival (OS), were included for the purposes of quantitative synthesis. Patients without clinical follow-up data or OS were excluded. Remaining articles were assessed for data extraction eligibility.ResultsA total of 17 patients met our inclusion criteria. Of these patients, 14 (82.4%) were male and 3 (17.6%) were female, with a mean age of 39.5±9.2 years (range 19-60 years). Average CD4 count at diagnosis of glioblastoma was 358.9±193.4 cells/mm3. Tumor progression rather than AIDS-associated complications dictated patient survival. There was a trend towards increased median survival with HAART treatment (12.0 vs 7.5 months, p=0.10).ConclusionOur data suggests that HAART is associated with improved survival in patients with HIV-associated glioblastoma, although the precise mechanisms underlying this improvement remain unclear