364 research outputs found
Cell and MaterialāSpecific Phage Display Peptides Increase iPSāMSC Mediated Bone and Vasculature Formation In Vivo
Biomimetically designed materials matching the chemical and mechanical properties of tissue support higher mesenchymal stem cell (MSC) adhesion. However, directing cellāspecific attachment and ensuring uniform cell distribution within the interior of 3D biomaterials remain key challenges in healing critical sized defects. Previously, a phage display derived MSCāspecific peptide (DPIYALSWSGMA, DPI) was combined with a mineral binding sequence (VTKHLNQISQSY, VTK) to increase the magnitude and specificity of MSC attachment to calciumāphosphate biomaterials in 2D. This study investigates how DPIāVTK influences quantity and uniformity of iPSāMSC mediated bone and vasculature formation in vivo. There is greater bone formation in vivo when iPSāMSCs are transplanted on boneālike mineral (BLM) constructs coated with DPIāVTK compared to VTK (p < 0.002), uncoated BLM (p < 0.037), acellular BLM/DPIāVTK (p < 0.003), and acellular BLM controls (p < 0.01). This study demonstrates, for the first time, the ability of nonānative phageādisplay designed peptides to spatially control uniform cell distribution on 3D scaffolds and increase the magnitude and uniformity of bone and vasculature formation in vivo. Taken together, the study validates phage display as a novel technology platform to engineer nonānative peptides with the ability to drive cell specific attachment on biomaterials, direct bone regeneration, and engineer uniform vasculature in vivo.Nonānative peptides derived from a combinatorial phage display are engineered to increase iPSāMSC attachment on biomaterials and increase the quantity and uniformity of bone and vasculature formation in vivo. Findings validate phage display as a new technology platform to engineer the interface between selective cell populations and specific biomaterial chemistries.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149285/1/adhm201801356_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149285/2/adhm201801356.pd
MySQL extension automatic porting to PDO for PHP migration and security improvement
In software management, the upgrade of programming languages may introduce critical issues. This is the case of PHP, the fifth version of which is going towards the end of the support. The new release improves on different aspects, but removes the old deprecated MySQL extensions, and supports only the newer library of functions for the connection to the databases. The software systems already in place need to be renewed to be compliant with respect to the new language version. The conversion of the source code, to be safe against injection attacks, should involve also the transformation of the query code. The purpose of this work is the design of specific tool that automatically applies the required transformation yielding to a precise and efficient conversion procedure. The tool has been applied to different projects to provide evidence of its effectiveness
In vivo and in vitro tracking of erosion in biodegradable materials using non-invasive fluorescence imaging
Author Manuscript 2012 March 1.The design of erodible biomaterials relies on the ability to program the in vivo retention time, which necessitates real-time monitoring of erosion. However, in vivo performance cannot always be predicted by traditional determination of in vitro erosion[superscript 1, 2] , and standard methods sacrifice samples or animals[superscript 3], preventing sequential measures of the same specimen. We harnessed non-invasive fluorescence imaging to sequentially follow in vivo material-mass loss to model the degradation of materials hydrolytically (PEG:dextran hydrogel) and enzymatically (collagen). Hydrogel erosion rates in vivo and in vitro correlated, enabling the prediction of in vivo erosion of new material formulations from in vitro data. Collagen in vivo erosion was used to infer physiologic in vitro conditions that mimic erosive in vivo environments. This approach enables rapid in vitro screening of materials, and can be extended to simultaneously determine drug release and material erosion from a drug-eluting scaffold, or cell viability and material fate in tissue-engineering formulations.National Institutes of Health (U.S.) (GM/HL 49039)National Institutes of Health (U.S.) (UL1 RR 025758
IC-Cut: A Compositional Search Strategy for Dynamic Test Generation
Abstract. We present IC-Cut, short for āInterface-Complexity-based Cutā, a new compositional search strategy for systematically testing large programs. IC-Cut dynamically detects function interfaces that are simple enough to be cost-effective for summarization. IC-Cut then hierarchically decomposes the program into units defined by such functions and their sub-functions in the call graph. These units are tested independently, their test results are recorded as low-complexity function summaries, and the summaries are reused when testing higher-level functions in the call graph, thus limiting overall path explosion. When the decomposed units are tested exhaustively, they constitute verified components of the program. IC-Cut is run dynamically and on-the-fly during the search, typically refining cuts as the search advances. We have implemented this algorithm as a new search strategy in the whitebox fuzzer SAGE, and present detailed experimental results ob-tained when fuzzing the ANI Windows image parser. Our results show that IC-Cut alleviates path explosion while preserving or even increasing code coverage and bug finding, compared to the current generational-search strategy used in SAGE.
Proving Memory Safety of the ANI Windows Image Parser Using Compositional Exhaustive Testing
We report in this paper how we proved memory safety of a complex Windows image parser written in low-level C in only three months of work and using only three core tech-niques, namely (1) symbolic execution at the x86 binary level, (2) exhaustive program path enumeration and testing, and (3) user-guided program decomposition and summariza-tion. We also used a new tool, named MicroX, for executing code fragments in isolation using a custom virtual machine designed for testing purposes. As a result of this work, we are able to prove, for the first time, that a Windows image parser is memory safe, i.e., free of any buffer-overflow secu-rity vulnerabilities, modulo the soundness of our tools and several additional assumptions regarding bounding input-dependent loops, fixing a few buffer-overflow bugs, and ex-cluding some code parts that are not memory safe by design. In the process, we also discovered and fixed several limita-tions in our tools, and narrowed the gap between systematic testing and verification. 1
Global well-posedness of the KP-I initial-value problem in the energy space
We prove that the KP-I initial value problem is globally well-posed in the
natural energy space of the equation
Multimodal neuro-nanotechnology: Challenging the existing paradigm in glioblastoma therapy
Integrating multimodal neuro- and nanotechnology-enabled precision immunotherapies with extant systemic immunotherapies may finally provide a significant breakthrough for combatting glioblastoma (GBM). The potency of this approach lies in its ability to train the immune system to efficiently identify and eradicate cancer cells, thereby creating anti-tumor immune memory while minimizing multi-mechanistic immune suppression. A critical aspect of these therapies is the controlled, spatiotemporal delivery of structurally defined nanotherapeutics into the GBM tumor microenvironment (TME). Architectures such as spherical nucleic acids or poly(beta-amino ester)/dendrimer-based nanoparticles have shown promising results in preclinical models due to their multivalency and abilities to activate antigen-presenting cells and prime antigen-specific T cells. These nanostructures also permit systematic variation to optimize their distribution, TME accumulation, cellular uptake, and overall immunostimulatory effects. Delving deeper into the relationships between nanotherapeutic structures and their performance will accelerate nano-drug development and pave the way for the rapid clinical translation of advanced nanomedicines. In addition, the efficacy of nanotechnology-based immunotherapies may be enhanced when integrated with emerging precision surgical techniques, such as laser interstitial thermal therapy, and when combined with systemic immunotherapies, particularly inhibitors of immune-mediated checkpoints and immunosuppressive adenosine signaling. In this perspective, we highlight the potential of emerging treatment modalities, combining advances in biomedical engineering and neurotechnology development with existing immunotherapies to overcome treatment resistance and transform the management of GBM. We conclude with a call to action for researchers to leverage these technologies and accelerate their translation into the clinic
A histomorphometric meta-analysis of sinus elevation with various grafting materials
Several grafting materials have been used in sinus augmentation procedures including autogenous bone, demineralized freeze-dried bone (DFDBA), hydroxyapatite, Ī²-tricalcium phosphate (Ī²-TCP), anorganic deproteinized bovine bone and combination of these and others. Up to now a subject of controversy in maxillofacial surgery and dentistry is, what is the most appropriate graft material for sinus floor augmentation
Asymptotic Lower Bounds for a class of Schroedinger Equations
We shall study the following initial value problem: \begin{equation}{\bf
i}\partial_t u - \Delta u + V(x) u=0, \hbox{} (t, x) \in {\mathbf R} \times
{\mathbf R}^n, \end{equation} where is a real short--range
potential, whose radial derivative satisfies some supplementary assumptions.
More precisely we shall present a family of identities satisfied by the
solutions to the previous Cauchy problem. As a by--product of these identities
we deduce some uniqueness results and a lower bound for the so called local
smoothing which becomes an identity in a precise asymptotic sense.Comment: 24 pages. to appear on Comm. Math. Phy
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