Gender-Specific Anterior Cruciate Ligament – Gait Forces

The purpose of this study was to investigate gender-based differences in gait biomechanics and to evaluate those effects on forces generated on the ACL during walking. Estimation of gender-specific ACL forces in the frontal plane can provide a better understanding of the biomechanical patterns underlying higher female injury risk. The present study used a sample from the Fels Longitudinal Study to test the hypothesis that there are significant gender-differences in frontal plane ACL loading during walking. A cross-sectional sample of 178 participants, including 79 males and 99 females was used to evaluate differences in gait kinetics. Females walked at higher cadence with narrower steps (P \u3c 0.05). No difference was observed in the peak flexion force and knee rotation moment between males and females (P = 0.51 and 0.07), respectively. Peak abduction moment was significantly lower among females than in males (P = 0.05). A regression equation was developed which considers a person’s weight and height in addition to forces which could give better estimate of the forces acting on the ligament. The peak force acting on the ACL during walking reaches as high as 0.44 of BW, regardless of gender

Mechanical Properties of Nanoparticles in the Drug Delivery Kinetics

Nanoparticle formulation is a recently developed drug delivery technology with enhanced targeting potential. Nanoparticles encapsulate the drug of choice and delivers it to the target via a targeting molecules (ex. antigen) located on the nanoparticle surface. Nanoparticles can even be targeted to deeply penetrating tissue and can be modeled to deliver drugs through the blood brain barrier. These advancements are providing better disease targeting such as to cancer and Alzheimer’s. Various polymers can be manufactured into nanoparticles. The polymers examined in this paper are polycaprolactone (PCL), poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA), and poly(glycolic acid) (PGA). The purpose of this study is to analyze the mechanical properties of these polymers to establish drug delivery trends and model pharmacokinetics and biotransport. We found that, in general, as the melting point, elastic modulus and tensile strength increases, the degradation rate also increases. PLA composite material may be an ideal polymer for drug delivery due to its good control of degradation

Transdermal Drug Delivery Systems: Analysis of Adhesion Failure

The most critical component of the TDDS is the adhesive, which is responsible for the safety, efficacy and quality of the patch. For drug delivery to successfully occur, the patch must adhere to the surface of the contact area. If a patch has inadequate adhesion, it is likely to fall off before the entire delivery period has been satisfied, leading to risks for the patient and others who may encounter the patch. Despite the critical concerns associated with the adhesive properties of the patches, the adhesion quality and failure mechanisms have not been fully studied. If certain molecules encounter the adhesive, it may cause irreversible altering of its chemical composition, which could render it unsuitable for transdermal applications. In many cases of TDDS failure, sweat is believed to be a culprit responsible for causing adhesive failure. The goal of this project is to investigate the chemical composition of the adhesive layer of a transdermal patch. The patch sample is a Sandoz Estradiol Transdermal System manufactured by Noven Pharmaceuticals, Inc., designed to deliver 0.1mg per day and contains 1.56mg of Estradiol USP, the active ingredient. By analyzing the chemical composition of a patch that has not been worn, versus a patch that has been worn, it may be possible to determine the chemical interaction that causes adhesive failure. Fourier Transform Infra-Red (FTIR) Spectroscopy (OPUS FTIR Spectrometer) was performed on an unused estradiol TDDS patch immediately after opening, and again after 24 hours in ambient air to investigate the potential for oxidation. The IR Spectrum was then analyzed, and the peaks were reviewed. The IR Spectra for the sample left out for 24 hours indicated lengthened peaks corresponding to C=O, C-O, and O-H, a decreased transmittance, and a wider bandwidth in those regions. Based on these results, it can be determined that oxidation does occur on a patch sample that is exposed to ambient air. In future works, additional patch samples will be collected and used for an extensive IR and UV analysis. By comparing the IR and UV Spectrum graphs of “used” patches that did not fail, with “failed” patches, it may be possible to identify a cause for premature patch failure related to sweat interactions

Biomimetic model of skeletal muscle isometric contraction: I. an energetic–viscoelastic model for the skeletal muscle isometric force twitch

This paper describes a revision of the Hill-type muscle model so that it will describe the chemo-mechanical energy conversion process (energetic) and the internal-element sti2ness variation (viscoelastic) during a skeletal muscle isometric force twitch contraction. The derivation of this energetic–viscoelastic model is described by a 3rst-order linear ordinary di2erential equation with constant energetic and viscoelastic coe5cients. The model has been implemented as part of a biomimetic model, which describes the excitation–contraction coupling necessary to drive the energetic–viscoelastic model. Finally, the energetic–viscoelastic model is validated by comparing its isometric force–time pro3le with that of various muscles reported in the literature

Identification of the Antibacterial Compound Produced by the Marine Epiphytic Bacterium Pseudovibrio sp. D323 and Related Sponge-Associated Bacteria

Surface-associated marine bacteria often produce secondary metabolites with antagonistic activities. In this study, tropodithietic acid (TDA) was identified to be responsible for the antibacterial activity of the marine epiphytic bacterium Pseudovibrio sp. D323 and related strains. Phenol was also produced by these bacteria but was not directly related to the antibacterial activity. TDA was shown to effectively inhibit a range of marine bacteria from various phylogenetic groups. However TDA-producers themselves were resistant and are likely to possess resistance mechanism preventing autoinhibition. We propose that TDA in isolate D323 and related eukaryote-associated bacteria plays a role in defending the host organism against unwanted microbial colonisation and, possibly, bacterial pathogens