In situ synthesis of size-controlled, stable silver nanoparticles within ultrashort peptide hydrogels and their anti-bacterial properties

We have developed a silver-releasing biomaterial with promising potential for wound healing applications. The material is made of ultrashort peptides which can self-assemble in water to form hydrogels. Silver nanoparticles (Ag NPs) were synthesized in situ within the biomaterial, using only UV irradiation and no additional chemical reducing agents. The synthetic strategy allows precise control of the nanoparticle size, with the network of peptide fibers preventing aggregation of Ag NPs. The biomaterial shows increased mechanical strength compared to the hydrogel control. We observed a sustained release of Ag NPs over a period of 14 days. This is a crucial prerequisite for effective anti-bacterial therapy. The ability to inhibit bacterial growth was tested using different bacterial strains, namely gram-negative Escherichia coli and Pseudomonas aeruginosa and gram-positive Staphylococcus aureus. Inhibition of bacterial growth was observed for all strains. The best results were obtained for Pseudomonas aeruginosa which is known for exhibiting multidrug resistance. Biocompatibility studies on HDFa cells, using Ag NP-containing hydrogels, did not show any significant influence on cell viability. We propose this silver-releasing hydrogel as an excellent biomaterial with great potential for applications in wound healing due to its low silver content, sustained silver nanoparticle release and biocompatibility

A study of charge storage in silicon oxide resulting from non-penetrating electron irradiation

Charge storage in silicon dioxide resulting from electron irradiatio

Maximal multihomogeneity of algebraic hypersurface singularities

From the degree zero part of logarithmic vector fields along an algebraic hypersurface singularity we indentify the maximal multihomogeneity of a defining equation in form of a maximal algebraic torus in the embedded automorphism group. We show that all such maximal tori are conjugate and in one-to-one correspondence to maxmimal tori in the degree zero jet of the embedded automorphism group. The result is motivated by Kyoji Saito's characterization of quasihomogeneity for isolated hypersurface singularities and extends its formal version and a result of Hauser and Mueller.Comment: 5 page

Charge storage effects in Mylar resulting from electron irradiation, June 1965 - June 1966

Charge storage effects in Mylar from electron irradiatio

Subjective Functional Knee Outcomes following Anterior Cruciate Ligament Reconstructive Surgery

It is established in the literature that primary repair of the anterior cruciate ligament (ACL) deficient knee is achieved through means of reconstructive surgery. However, with continuing advances in both the surgical technique performed and, consequently, the rehabilitation program implemented following reconstruction, the need for ongoing research becomes essential in evaluating the long-term effectiveness of such changes. Currently, the longterm follow-up studies available on ACL reconstructive surgery report information through means of clinical evaluation and objective testing measures with little or no emphasis on the value of the patient\u27s subjective responses. The purpose of this study is to determine the subjective functional knee outcomes obtained from a group of patients following ACL reconstruction and to demonstrate that subjective information is an essential component in predicting patient satisfaction and overall functional level. The methodology entailed contact of 325 patients who underwent bone-patellar tendon-bone autograft reconstructive surgery by mail through the use of a questionnaire form. A total of 90 subjects (n=90, 46 males and 44 females) with ages ranging from 18 to 52 years ~=28.79) were used in the data collection and statistical analysis. The results indicated that the three most predictive factors of the overall functional knee outcome reported subjectively by the patient include stability of the knee, stair climbing, and the occurrence of swelling. A postoperative data summary of the patients\u27 activity level following surgery revealed that there was a 47% return to a preinjury activity level or better. Significant variable associations were also found between the ability to predict the functional outcome of the knee and the type of surgical procedures performed. Further analysis of the subjective information obtained in this study suggests that subjective questioning of the patient is a valuable component which can be used in predicting patient satisfaction and the overall functional level of the knee following ACL reconstructive surgery

PEPTIDE-FUNCTIONALIZED MAGNETIC NANOPARTICLES FOR CANCER THERAPY APPLICATIONS

Lung cancer is one of the leading causes of cancer deaths in the United States. Radiation and chemotherapy are conventional treatments, but they result in serious side effects and the probability of tumor recurrence remains high. Therefore, there is an increasing need to enhance the efficacy of conventional treatments. Magnetic nanoparticles have been previously studied for a variety of applications such as magnetic resonance imaging contrast agents, anemia treatment, magnetic cell sorting and magnetically mediated hyperthermia (MMH). In this work, dextran coated iron oxide nanoparticles were developed and functionalized with peptides to target the nanoparticles to either the extracellular matrix (ECM) of tumor tissue or to localize the nanoparticles in subcellular regions after cell uptake. The magnetic nanoparticles were utilized for a variety of applications. First, heating properties of the nanoparticles were utilized to administer hyperthermia treatments combined with chemotherapy. The nanoparticles were functionalized with peptides to target fibrinogen in the ECM and extensively characterized for their physicochemical properties, and MMH combined with chemotherapy was able to enhance the toxicity of chemotherapy. The second application of the nanoparticles was magnetically mediated energy delivery. This treatment does not result in a bulk temperature rise upon actuation of the nanoparticles by an alternating magnetic field (AMF) but rather results in intracellular damage via friction from Brownian rotation or nanoscale heating effects from Neél relaxations. The nanoparticles were functionalized with a cell penetrating peptide to facilitate cell uptake and lysosomal escape. The intracellular effects of the internalized nanoparticles alone and with activation by an AMF were evaluated. Iron concentrations in vivo are highly regulated as excess iron can catalyze the formation of the hydroxyl radical through Fenton chemistry. Although often a concern of using iron oxide nanoparticles for therapeutic applications, these inherent toxicities were harnessed and utilized to enhance radiation therapy. Therefore, the third application of magnetic nanoparticles was their ability to catalyze reactive oxygen species formation and increase efficacy of radiation. Overall, iron oxide nanoparticles have a variety of cancer therapy applications and are a promising class of materials for increasing efficacy and reducing the side effects of conventional cancer treatments

Collision of plane gravitational and electromagnetic waves in a Minkowski background: solution of the characteristic initial value problem

We consider the collisions of plane gravitational and electromagnetic waves with distinct wavefronts and of arbitrary polarizations in a Minkowski background. We first present a new, completely geometric formulation of the characteristic initial value problem for solutions in the wave interaction region for which initial data are those associated with the approaching waves. We present also a general approach to the solution of this problem which enables us in principle to construct solutions in terms of the specified initial data. This is achieved by re-formulating the nonlinear dynamical equations for waves in terms of an associated linear problem on the spectral plane. A system of linear integral ``evolution'' equations which solve this spectral problem for specified initial data is constructed. It is then demonstrated explicitly how various colliding plane wave space-times can be constructed from given characteristic initial data.Comment: 33 pages, 3 figures, LaTeX. Accepted for publication in Classical and Quantum Gravit

Brightness enhancement at low luminance levels

The present study is an investigation of the variables which may produce or influence multiple pulse brightness enhancement at low luminance levels