In vitro Analysis of Microfluidic Neural Probes

The clinical impact of neural prostheses has been inhibited by a lack of functional stability of the devices due to acute and chronic reactive tissues\u27 responses in the brain. However, prosthetic stability could be improved via local drug administration or delivery of siRNA to mitigate the reactive tissues using microfluidic probes. Neural prosthetic probes have been previously developed, but had asymmetric and uneven distribution of fluid delivery to brain phantoms. Therefore, probes with different geometries and fluid delivery pores (holes ranging from 10 to 20 μm) were tested for functionality in vitro using a crystal violet/PBS solution. Compound light microscopy and image capture were utilized to record the diffusion of solution from probes into 1% w/v agarose. Solution diffusion was observed for 30 minutes and diffusion radii were observed for all probe geometries and hole diameters, thus confirming probe functionality. With functionality established, solution release from probes was characterized in vitro using Texas-Red labeled dextran pumped into agarose brain phantoms (1% w/v) at a constant rate. Fluorescence microscopy with automated image capture was employed to record the release profile of Texas-Red dextran. Release was monitored for 10 minutes and analyzed using Nikon Elements image analysis software. A significant difference in fluid delivery was observed for different probe geometries and hole diameters. The results suggest these novel probe designs could provide a more symmetric and even distribution of local drug or siRNA delivery during intervention treatment of reactive tissue in response to neural prostheses implantation

Brinell Limit Testing Machine - Final Design Report

In keeping with the California Polytechnic State University motto of “Learn by Doing”, this project was performed by Mechanical Engineering students Joe Cloutier, Josh Kessler, and Mike Jaskulsky II as their senior project. Starting in the Fall 2009 quarter and reaching completion with the end of the Spring 2010 quarter, this project provided these students with experience in application of a formal engineering design process in the solving of an open-ended engineering design problem, in developing and maintaining an engineering project schedule, as well as providing further experience working on an engineering team. As the engineers of Parker Aerospace seek to use different metals in their high performance bearing applications than have traditionally been used in the past, often the data does not exist for them to be able to accurately design against brinelling. To provide their engineers with this data, Parker Aerospace proposed the following as a senior project to Cal Poly’s seniors. They requested that a team of engineering students would design, fabricate, assemble, and validate through testing a machine that would determine the loads at the onset of brinelling for different metals and would allow for multiple measurements to be taken from each set of sample materials tested. Some of the secondary design requirements were for the test fixture to be portable, small enough to be used as a desktop unit, be able to accommodate a thermal chamber around the test area, and also provide measurements of the total deformation of the sample materials when under load. Also, time allowing, Parker Aerospace requested that the senior project team devote the last part of the last quarter to using the machine to provide data for a number of materials that they will provide. The loads that the test machine would need to deliver to test all material samples to the onset of brinelling were determined through hertzian contact stress analysis. These calculated loads were then used to determine the deflection of the sample materials, allowing for the sizing of structural components and selection of necessary sensors. The design for the fixture was developed around the initial design concept displayed in the Project Proposal by Parker Aerospace. After developing a number of different designs and variations of specific components of the fixture, the best of these design variations were presented to a panel of Parker Aerospace’s engineers during a Preliminary Design Review. From these designs, a final design was selected and various modifications were made as suggested by Parker. A final design was decided on and the rest of the project was completed by the end of the Spring quarter

Editorial for "Diffusion Tensor Imaging for Quantitative Assessment of Anterior Cruciate Ligament Injury Grades and Graft".

Tears to the anterior cruciate ligament (ACL) are common and serious knee injuries which tend to occur in young, active individuals. They result in functional impairment and require a period of relative immobilisation followed by rehabilitation, often leading to surgery. Individuals suffering from an ACL injury also have a higher risk of developing osteoarthritis as a long-term consequence(1, 2). ACL reconstructive surgery using a tendon graft remains the clinical standard of care to provide stability to the knee joint and allow patients to return to sport quicker. However, the question of when to allow patients to return to high-level sport remains hotly debated, as the risk of sustaining a second ACL rupture following reconstructive surgery is highest within the subsequent two years(3). While conventional MRI methods continue to provide high diagnostic structural information for ACL injuries, they are unable to deliver advanced quantitative measures required for biological tissue characterisation and longitudinal observation of graft maturation. Promising techniques such as diffusion tensor imaging (DTI), are used for research purposes only and have not yet made the translation into routine clinical application.University of Cambridg

A Measurement of the Rate of Type Ia Supernovae at Redshift z ≈ 0.1 from the First Season of the SDSS-II Supernova Survey

We present a measurement of the rate of type Ia supernovae (SNe Ia) from the first of three seasons of data from the SDSS-II Supernova Survey. For this measurement, we include 17 SNe Ia at redshift z ≤ 0.12. Assuming a flat cosmology with m = 0.3 = 1 − , we find a volumetric SN Ia rate of [2.93+0.17 −0.04(systematic)+0.90 −0.71(statistical)]×10−5 SNe Mpc−3 h3 70 year−1, at a volumeweighted mean redshift of 0.09. This result is consistent with previous measurements of the SN Ia rate in a similar redshift range. The systematic errors are well controlled, resulting in the most precise measurement of the SN Ia rate in this redshift range. We use a maximum likelihood method to fit SN rate models to the SDSS-II Supernova Survey data in combination with other rate measurements, thereby constraining models for the redshift-evolution of the SN Ia rate. Fitting the combined data to a simple power-law evolution of the volumetric SN Ia rate, rV ∝ (1 + z) , we obtain a value of β = 1.5 ± 0.6, i.e. the SN Ia rate is determined to be an increasing function of redshift at the ∼ 2.5σ level. Fitting the results to a model in which the volumetric SN rate, rV = Aρ(t) + Bρ˙(t), where ρ(t) is the stellar mass density and ρ˙(t) is the star formation rate, we find A = (2.8 ± 1.2) × 10−14 SNe M−1 ⊙ year−1, B = (9.3+3.4 −3.1) × 10−4 SNe M−1 ⊙

SNANA: A Public Software Package for Supernova Analysis

We describe a general analysis package for supernova (SN) light curves, called SNANA, that contains a simulation, light curve fitter, and cosmology fitter. The software is designed with the primary goal of using SNe Ia as distance indicators for the determination of cosmological parameters, but it can also be used to study efficiencies for analyses of SN rates, estimate contamination from non-Ia SNe, and optimize future surveys. Several SN models are available within the same software architecture, allowing technical features such as K-corrections to be consistently used among multiple models, and thus making it easier to make detailed comparisons between models. New and improved light-curve models can be easily added. The software works with arbitrary surveys and telescopes and has already been used by several collaborations, leading to more robust and easy-to-use code. This software is not intended as a final product release, but rather it is designed to undergo continual improvements from the community as more is learned about SNe. Below we give an overview of the SNANA capabilities, as well as some of its limitations. Interested users can find software downloads and more detailed information from the manuals at http://www.sdss.org/supernova/SNANA.html .Comment: Accepted for publication in PAS

Positive Identification of LSB Image Steganography Using Cover Image Comparisons

In this paper we introduce a new software concept specifically designed to allow the digital forensics professional to clearly identify and attribute instances of LSB image steganography by using the original cover image in side-by-side comparison with a suspected steganographic payload image. The “CounterSteg” software allows detailed analysis and comparison of both the original cover image and any modified image, using sophisticated bit- and color-channel visual depiction graphics. In certain cases, the steganographic software used for message transmission can be identified by the forensic analysis of LSB and other changes in the payload image. The paper demonstrates usage and typical forensic analysis with eight commonly available steganographic programs. Future work will attempt to automate the typical types of analysis and detection. This is important, as currently there is a steep rise in the use of image LSB steganographic techniques to hide the payload code used by malware and viruses, and for the purposes of data exfiltration. This results because of the fact that the hidden code and/or data can more easily bypass virus and malware signature detection in such a manner as being surreptitiously hidden in an otherwise innocuous image file

Testing Models of Intrinsic Brightness Variations in Type Ia Supernovae, and their Impact on Measuring Cosmological Parameters

For spectroscopically confirmed Type Ia supernovae we evaluate models of intrinsic brightness variations with detailed data/Monte Carlo comparisons of the dispersion in the following quantities: Hubble-diagram scatter, color difference (B-V-c) between the true B-V color and the fitted color (c) from the SALT-II light curve model, and photometric redshift residual. The data sample includes 251 ugriz light curves from the 3-season Sloan Digital Sky Survey-II, and 191 griz light curves from the Supernova Legacy Survey 3-year data release. We find that the simplest model of a wavelength-independent (coherent) scatter is not adequate, and that to describe the data the intrinsic scatter model must have wavelength-dependent variations. We use Monte Carlo simulations to examine the standard approach of adding a coherent scatter term in quadrature to the distance-modulus uncertainty in order to bring the reduced chi2 to unity when fitting a Hubble diagram. If the light curve fits include model uncertainties with the correct wavelength dependence of the scatter, we find that the bias on the dark energy equation of state parameter $w$ is negligible. However, incorrect model uncertainties can lead to a significant bias on the distance moduli, with up to ~0.05 mag redshift-dependent variation. For the recent SNLS3 cosmology results we estimate that this effect introduces an additional systematic uncertainty on $w$ of ~0.02, well below the total uncertainty. However, this uncertainty depends on the samples used, and thus this small $w$-uncertainty is not guaranteed in future cosmology results.Comment: accepted by Ap

High Return to Play Rate and Reduced Career Longevity Following Surgical Management of Athletic Pubalgia in National Basketball Association Players

PURPOSE: To assess the effects of surgical treatment of athletic pubalgia (AP) on game use and performance metrics in National Basketball Association (NBA) players. METHODS: A retrospective review of all NBA players who underwent surgical management for AP from 1996 to 2018 was performed. A matched control group was created for comparison. The index period was defined as the entire NBA season in which surgery occurred, including the corresponding offseason. Player demographics, use (games played, games started, and minutes per game) and performance (player efficiency rating) metrics were collected for all players. Statistical analysis was performed to compare data before and after return to play. RESULTS: Thirty players with a history of surgical management for AP were included in the final analysis. Following surgery for AP, NBA players were found to have a return to play (RTP) rate of 90.91% (30/33). The average RTP following surgery was 4.73 ± 2.62 months. Compared with control athletes, athletes in the AP group played significantly fewer seasons postinjury (4.17 ± 2.70 vs 5.49 ± 3.04 seasons, respectively; P = .02). During the first year following RTP, NBA players experienced significant reductions in game use and performance, both when compared with the year prior and matched control athletes (P \u3c .05). At 3-year follow-up, players continued to demonstrate significant reductions in game use (minutes per game, P \u3c .05) but not performance. CONCLUSIONS: Following surgical treatment of AP, NBA players demonstrated a high RTP rate, but shortened career. A short-term reduction in game use and performance metrics was found the year of return following surgery. However, 3-year follow-up performance metrics normalized when compared with healthy controls. STUDY DESIGN: Level III; retrospective case-control study

Quantitative analysis of the ACL and PCL using T1rho and T2 relaxation time mapping: an exploratory, cross-sectional comparison between OA and healthy control knees.

BACKGROUND: Quantitative magnetic resonance imaging (MRI) methods such as T1rho and T2 mapping are sensitive to changes in tissue composition, however their use in cruciate ligament assessment has been limited to studies of asymptomatic populations or patients with posterior cruciate ligament tears only. The aim of this preliminary study was to compare T1rho and T2 relaxation times of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) between subjects with mild-to-moderate knee osteoarthritis (OA) and healthy controls. METHODS: A single knee of 15 patients with mild-to-moderate knee OA (Kellgren-Lawrence grades 2-3) and of 6 age-matched controls was imaged using a 3.0 T MRI. Three-dimensional (3D) fat-saturated spoiled gradient recalled-echo images were acquired for morphological assessment and T1ρ- and T2-prepared pseudo-steady-state 3D fast spin echo images for compositional assessment of the cruciate ligaments. Manual segmentation of whole ACL and PCL, as well as proximal / middle / distal thirds of both ligaments was carried out by two readers using ITK-SNAP and mean relaxation times were recorded. Variation between thirds of the ligament were assessed using repeated measures ANOVAs and differences in these variations between groups using a Kruskal-Wallis test. Inter- and intra-rater reliability were assessed using intraclass correlation coefficients (ICCs). RESULTS: In OA knees, both T1rho and T2 values were significantly higher in the distal ACL when compared to the rest of the ligament with the greatest differences in T1rho (e.g. distal mean = 54.5 ms, proximal = 47.0 ms, p < 0.001). The variation of T2 values within the PCL was lower in OA knees (OA: distal vs middle vs proximal mean = 28.5 ms vs 29.1 ms vs 28.7 ms, p = 0.748; Control: distal vs middle vs proximal mean = 26.4 ms vs 32.7 ms vs 33.3 ms, p = 0.009). ICCs were excellent for the majority of variables. CONCLUSION: T1rho and T2 mapping of the cruciate ligaments is feasible and reliable. Changes within ligaments associated with OA may not be homogeneous. This study is an important step forward in developing a non-invasive, radiological biomarker to assess the ligaments in diseased human populations in-vivo.Declarations Ethics approval and consent to participate This study was approved by the East of England Cambridge Central Research Ethics Committee and written informed consent was given by all subjects included in the study. All methods were carried out in accordance with relevant guidelines and regulations. Consent for publication Not Applicable Availability of data and materials The datasets generated and analysed during the current study are not publicly available due to unattained permission from participants and research ethics committee but could be made available from JWM (email: [email protected]). Competing interests JWM, DAK and JDK acknowledge funding support from GlaxoSmithKline for their studentships and fellowships, respectively. JWM is an employee of AstraZeneca. CDSR, VAC and SMM have no competing interests to declare. Acknowledgements The Addenbrooke's Hospital Magnetic Resonance Imaging and Spectroscopy (MRIS) staff are thanked for their help with arranging and conducting the study MRI examinations. We also acknowledge the support of the Addenbrooke's Charitable Trust and the National Institute for Health Research Cambridge Biomedical Research Centre. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care. Funding The study was funded by an Experimental Medicine Initiative PhD studentship from the University of Cambridge [grant number RG81329] and by GlaxoSmithKline [grant number RG87552]. Authors' contributions Writing of original draft manuscript: CDSR. Study design and coordination: CDSR, JWM, JDK and SMM. Data acquisition: JWM and JDK. Data curation, analysis and interpretation: CDSR, JWM, VAC, JDK, DAK and SMM. Statistical analysis: CDSR and JWM. Review and editing of manuscript: JWM, VAC, JDK, DAK and SMM. All authors read and approved the final manuscript