Acute cell viability and nitric oxide release in lateral menisci following closed-joint knee injury in a lapine model of post-traumatic osteoarthritis

BACKGROUND: Traumatic impaction is known to cause acute cell death and macroscopic damage to cartilage and menisci in vitro. The purpose of this study was to investigate cell viability and macroscopic damage of the medial and lateral menisci using an in situ model of traumatic loading. Furthermore, the release of nitric oxide from meniscus, synovium, cartilage, and subchondral bone was also documented. METHODS: The left limbs of five rabbits were subjected to tibiofemoral impaction resulting in anterior cruciate ligament (ACL) rupture and meniscal damage. Meniscal tear morphology was assessed immediately after trauma and cell viability of the lateral and medial menisci was assessed 24 hrs post-injury. Nitric oxide (NO) released from joint tissues to the media was assayed at 12 and 24 hrs post injury. RESULTS: ACL and meniscal tearing resulted from the traumatic closed joint impact. A significant decrease in cell viability was observed in the lateral menisci following traumatic impaction compared to the medial menisci and control limbs. While NO release was greater in the impacted joints, this difference was not statistically significant. CONCLUSION: This is the first study to investigate acute meniscal viability following an in situ traumatic loading event that results in rupture of the ACL. The change in cell viability of the lateral menisci may play a role in the advancement of joint degeneration following traumatic knee joint injury. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1471-2474-15-297) contains supplementary material, which is available to authorized users

Absorption of spherical bubbles in a square microchannel

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.Microfluidics is a fast growing field in which the manipulation of bubbles in liquid phase is of utmost importance. In this paper, the absorption of spherical bubbles in a square microchannel is investigated for a bubbly flow. Numerical simulations of the gas-liquid two-phase flow and the mass transfer around spherical bubbles in a square microchannel are carried out. Correlations are established for the bubble velocity and the mass transfer rate. A model for the dissolution of spherical bubbles along a square microchannel is proposed in the case of the bubbly flow regime and validated using existing experimental data. This model can be used, for instance, for designing microabsorbers for lab-on-a-chip applications

Connectivity-enhanced diffusion analysis reveals white matter density disruptions in first episode and chronic schizophrenia.

Reduced fractional anisotropy (FA) is a well-established correlate of schizophrenia, but it remains unclear whether these tensor-based differences are the result of axon damage and/or organizational changes and whether the changes are progressive in the adult course of illness. Diffusion MRI data were collected in 81 schizophrenia patients (54 first episode and 27 chronic) and 64 controls. Analysis of FA was combined with "fixel-based" analysis, the latter of which leverages connectivity and crossing-fiber information to assess both fiber bundle density and organizational complexity (i.e., presence and magnitude of off-axis diffusion signal). Compared with controls, patients with schizophrenia displayed clusters of significantly lower FA in the bilateral frontal lobes, right dorsal centrum semiovale, and the left anterior limb of the internal capsule. All FA-based group differences overlapped substantially with regions containing complex fiber architecture. FA within these clusters was positively correlated with principal axis fiber density, but inversely correlated with both secondary/tertiary axis fiber density and voxel-wise fiber complexity. Crossing fiber complexity had the strongest (inverse) association with FA (r = -0.82). When crossing fiber structure was modeled in the MRtrix fixel-based analysis pipeline, patients exhibited significantly lower fiber density compared to controls in the dorsal and posterior corpus callosum (central, postcentral, and forceps major). Findings of lower FA in patients with schizophrenia likely reflect two inversely related signals: reduced density of principal axis fiber tracts and increased off-axis diffusion sources. Whereas the former confirms at least some regions where myelin and or/axon count are lower in schizophrenia, the latter indicates that the FA signal from principal axis fiber coherence is broadly contaminated by macrostructural complexity, and therefore does not necessarily reflect microstructural group differences. These results underline the need to move beyond tensor-based models in favor of acquisition and analysis techniques that can help disambiguate different sources of white matter disruptions associated with schizophrenia

PREDICTION OF ANKLE JOINT TORQUES USING ARTIFICIAL NEURAL NETWORKS

Major ankle sprains in sports are thought to be due to high levels of ankle torsion. The purpose of this study was to develop a method for measuring in vivo ankle torques developed by athletes. Motion capture, force plate, and insole pressure measurements were used to develop generalized regression neural networks to predict maximum ankle torque and rate of ankle torque based on insole pressures. It was found that network prediction accuracy depended on the number of subjects used for training, as well as the method of pressure sensor grouping. Further work will be performed to determine optimal subject and pressure sensor groupings

Investigation of the electroplastic effect using nanoindentation

A promising approach to deform metallic-intermetallic composite materials is the application of electric current pulses during the deformation process to achieve a lower yield strength and enhanced elongation to fracture. This is known as the electroplastic effect. In this work, a novel setup to study the electroplastic effect during nanoindentation on individual phases and well-defined interfaces was developed. Using a eutectic Al-Al2Cu alloy as a model material, electroplastic nanoindentation results were directly compared with macroscopic electroplastic compression tests. The results of the micro- and macroscopic investigations reveal current induced displacement shifts and stress drops, respectively, with the first displacement shift/stress drop being higher than the subsequent ones. A higher current intensity, higher loading rate and larger pulsing interval all cause increased displacement shifts. This observation, in conjunction with the fact that the first displacement shift is highest, strongly indicates that de-pinning of dislocations from obstacles dominates the mechanical response, rather than solely thermal effects

Primary Care Case Conferences to Mitigate Social Determinants of Health: A Case Study from One FQHC System

Objective: Given the increasing difficulty healthcare providers face in addressing patients’ complex social circumstances and underlying health needs, organizations are considering team-based approaches including case conferences. We sought to document various perspectives on the facilitators and challenges of conducting case conferences in primary care settings. Study Design: Qualitative study using semi-structured telephone interviews Methods: We conducted 22 qualitative interviews with members of case conferencing teams, including physicians, nurses, and social workers from a Federally Qualified Health Clinic, as well as local county public health nurses. Interviews were recorded, transcribed, and reviewed using thematic coding to identify key themes/subthemes. Results: Participants reported perceived benefits to patients, providers, and healthcare organizations including better care, increased inter-professional communication, and shared knowledge. Perceived challenges related to underlying organizational processes and priorities. Perceived facilitators for successful case conferences included generating and maintaining a list of patients to discuss during case conference sessions and team members being prepared to actively participate in addressing tasks and patient needs during each session. Participants offered recommendations for further improving case conferences for patients, providers, and organizations. Conclusions: Case conferences may be a feasible approach to understanding patient’s complex social needs. Participants reported that case conferences may help mitigate the effects of these social issues and that they foster better inter-professional communication and care planning in primary care. The case conference model requires administrative support and organizational resources to be successful. Future research should explore how case conferences fit into a larger population health organizational strategy so that they are resourced commensurately

Plasticity of topologically close-packed phases in the Fe-Ta(-Al) system

Understanding the structure-property relationships of materials plays a significant role in the development of materials for technical applications. Due to the many possible combinations of two or more elements, intermetallic phases can be very interesting for these developments. High strength up to high temperatures makes intermetallics promising materials for high-temperature applications. However, their complex structure, resulting in a pronounced brittleness, has so far limited their applicability. We focus on the understanding of plastic deformation in topologically close-packed (TCP) phases, which form one of the largest groups of intermetallics. To do this, we use nanomechanical tests that allow us to study plasticity even in the most brittle materials. Here, we consider the Fe-Ta(-Al) system that contains two closely related TCP phases, a C14 Laves phase and a µ-phase. The building block-like structure of these phases enables a systematic investigation as well as a transfer of the findings to other complex crystals. The mechanical properties of the two TCP phases in the Fe-Ta(-Al) system, investigated by state-of-the-art micromechanical testing, are introduced in this work. The influence of the crystal structure and chemical composition on the mechanical properties and the deformation mechanisms of the TCP phases are discussed

Infection and venous thromboembolism in patients undergoing colorectal surgery: what is the relationship?

BACKGROUND: There is evidence demonstrating an association between infection and venous thromboembolism. We recently identified this association in the postoperative setting; however, the temporal relationship between infection and venous thromboembolism is not well defined OBJECTIVE: We sought to determine the temporal relationship between venous thromboembolism and postoperative infectious complications in patients undergoing colorectal surgery. DESIGN, SETTING, AND PATIENTS: A retrospective cohort analysis was performed using data for patients undergoing colorectal surgery in the National Surgical Quality Improvement Project 2010 database. MAIN OUTCOME MEASURES: The primary outcome measures were the rate and timing of venous thromboembolism and postoperative infection among patients undergoing colorectal surgery during 30 postoperative days. RESULTS: Of 39,831 patients who underwent colorectal surgery, the overall rate of venous thromboembolism was 2.4% (n = 948); 729 (1.8%) patients were diagnosed with deep vein thrombosis, and 307 (0.77%) patients were diagnosed with pulmonary embolism. Eighty-eight (0.22%) patients were reported as developing both deep vein thrombosis and pulmonary embolism. Following colorectal surgery, the development of a urinary tract infection, pneumonia, organ space surgical site infection, or deep surgical site infection was associated with a significantly increased risk for venous thromboembolism. The majority (52%-85%) of venous thromboembolisms in this population occurred the same day or a median of 3.5 to 8 days following the diagnosis of infection. The approximate relative risk for developing any venous thromboembolism increased each day following the development of each type of infection (range, 0.40%-1.0%) in comparison with patients not developing an infection. LIMITATIONS: We are unable to account for differences in data collection, prophylaxis, and venous thromboembolism surveillance between hospitals in the database. Additionally, there is limited patient follow-up. CONCLUSIONS: These findings of a temporal association between infection and venous thromboembolism suggest a potential early indicator for using certain postoperative infectious complications as clinical warning signs that a patient is more likely to develop venous thromboembolism. Further studies into best practices for prevention are warranted

Pilot Randomized Trial of Active Music Engagement Intervention Parent Delivery for Young Children With Cancer

Objectives: To examine the feasibility/acceptability of a parent-delivered Active Music Engagement (AME + P) intervention for young children with cancer and their parents. Secondary aim to explore changes in AME + P child emotional distress (facial affect) and parent emotional distress (mood; traumatic stress symptoms) relative to controls. Methods: A pilot two-group randomized trial was conducted with parents/children (ages 3-8 years) receiving AME + P ( n  =  9) or attention control ( n  =  7). Feasibility of parent delivery was assessed using a delivery checklist and child engagement; acceptability through parent interviews; preliminary outcomes at baseline, postintervention, 30 days postintervention. Results: Parent delivery was feasible, as they successfully delivered AME activities, but interviews indicated parent delivery was not acceptable to parents. Emotional distress was lower for AME + P children, but parents derived no benefit. Conclusions: Despite child benefit, findings do not support parent delivery of AME + P

Impact testing to determine the mechanical properties of articular cartilage in isolation and on bone

The original publication is available at www.springerlink.comNon peer reviewedPostprin