The development of an automated microscope image tracking and analysis system.

Microscopy image analysis plays a crucial role in understanding cellular behavior and uncovering important insights in various biological and medical research domains. Tracking cells within the time-lapse microscopy images is a fundamental technique that enables the study of cell dynamics, interactions, and migration. While manual cell tracking is possible, it is time-consuming and prone to subjective biases that impact results. In order to solve this issue, we sought to create an automated software solution, named cell analyzer, which is able to track cells within microscopy images with minimal input required from the user. The program of cell analyzer was written in Python utilizing the open source computer vision (OpenCV) library and featured a graphical user interface that makes it easy for users to access. The functions of all codes were verified through closeness, area, centroid, contrast, variance, and cell tracking test. Cell analyzer primarily utilizes image preprocessing and edge detection techniques to isolate cell boundaries for detection and analysis. It uniquely recorded the area, displacement, speed, size, and direction of detected cell objects and visualized the data collected automatically for fast analysis. Our cell analyzer provides an easy-to-use tool through a graphical user interface for tracking cell motion and analyzing quantitative cell images.

Program Infrastructure the Key to Success: A Pilot Crosswalk Installation to Promote Walkability, Pedestrian Safety, and Physical Activity in the U.S. Virgin Islands.

BACKGROUND & AIMS: While physical inactivity can contribute to chronic diseases, regular activity like walking can help prevent them. In 2010, one in three adults in the U.S. Virgin Islands (USVI) was physically inactive, higher than most U.S. states and territories. There are few walkable destinations and sidewalks along streets in the USVI. Since community- and street-scale design features can influence walking, we convened a 3-day walkability institute in the USVI to (1) learn about physical activity and best practices for design and (2) develop public health infrastructure that supports implementation. Island teams were formed to develop and implement a territory-wide action plan, focused on passing a Complete Streets policy, and demonstration projects on the islands of St. Croix, St. John, and St. Thomas to advance and pass this policy. An example of the demonstration projects and their significance is the completed one in St. Croix, which is the focus of this article. METHODS: Island teams applied critical components of functioning program infrastructure as described in the Component Model of Infrastructure (CMI) such as engaged data, multilevel leadership, responsive plans and planning, and networked partnerships. We evaluated whether a crosswalk installation in St. Croix could alter driver and pedestrian behavior and create a safer environment for pedestrians. Observers recorded pedestrian crossing time, driver speed, and other behaviors before and after crosswalk installation. RESULTS: Pedestrians took significantly fewer average seconds to cross the street in the postdemonstration period (9.83) compared with predemonstration (13.4) (p = .03). Average car speed declined between the predemonstration (24.3) and long-term demonstration periods (p < .01) and from the postdemonstration (24.7) to the long-term demonstration period (18.2) (p < .01). A greater percentage of pedestrians used the crosswalk to cross the street between the postdemonstration (12.5%) and long-term demonstration periods (53.7%) (p < .01). IMPLICATIONS: The demonstration project in St. Croix shows that improvements to built environment infrastructure can increase safety for pedestrians, thus improving walkability in the USVI. We discuss the importance of CMI elements observed in the success of the St. Croix demonstration and its effectiveness in promoting a Complete Streets policy and the lack of these elements on St. John hindering progress there. Public health practitioners can apply the CMI to future physical activity promotion projects in the USVI and other settings as having functioning program infrastructure helps overcome challenges including natural disasters and a global pandemic and can achieve progress toward sustained policy and systems change.

Redefining shelter: humanitarian sheltering.

Shelter is one of the most 'intractable problems' in humanitarian aid and yet there is little clarity on an overarching definition. Terminology for shelter and housing is often conflated, and the most prominent definition does not fully reflect recent progress in the Shelter and Settlements Sector. This paper explores the varying terminology utilised in definitions of shelter within humanitarian aid since 1990, reflecting on the concepts of 'shelter' and 'housing', alongside surrounding perceptions of 'house' versus 'home', and related measures of adequacy. The current, most prolific definition is also deconstructed, demonstrating ambiguity in some of terminology such as 'dignity' and 'privacy', and revealing that interpretation of this definition depends on the reader's knowledge. Lastly, a new definition of 'sheltering' is proposed, encompassing five key reflections: the concept of process over object; the inclusion of communities and individuals; the commonality of long-term sheltering; the wider effects of shelter; and the impacts on host communities and environment.

Sampling Methodology and Reliability of a Representative Walkability Audit.

Background: Physical inactivity is a public health concern in the US Virgin Islands (USVI). A contributing factor may be a lack of pedestrian infrastructure and other environmental supports for walking. In this manuscript, we describe the methods used to conduct a walkability audit of environmental features related to physical activity in the USVI. Methods: In 2016, volunteer auditors conducted the audit using a modified version of the Microscale Audit of Pedestrian Streetscapes tool. A two-stage sampling method was developed using publicly available census data to select a sample of estates (n=46) and street segments (n=1,550; 99.2 km) across the USVI. A subset of segments was audited by two independent auditors, and inter-rater reliability was assessed using Cohen's kappa and percent agreement. Results: Audits were completed on 1,114 segments (94.6 km), and estimates were weighted to represent accessible public street length in the study area (1,155.9 km). Most items on the audit tool (62.7%) demonstrated good to excellent reliability. We found that it was feasible to conduct a reliable audit of environmental features related to physical activity across a large sample of streets in the USVI. Conclusions: These methods can be replicated in other settings to collect comprehensive data that can be used to guide strategies to improve the walkability of communities.

Community and Street-Scale Supports for Walking in the US Virgin Islands Before the 2017 Hurricanes.

OBJECTIVES: To determine the prevalence of community and street-scale design features that promote walking across the US Virgin Islands (USVI). METHODS: In May 2016, the USVI Department of Health, with technical assistance from the Centers for Disease Control and Prevention, conducted a territory-wide audit with a validated tool. We selected street segments (n = 1114) via a 2-stage sampling method, and estimates were weighted to be representative of publicly accessible street length. RESULTS: Overall, 10.7% of the street length contained a transit stop, 11.3% had sidewalks, 21.7% had at least 1 destination (e.g., stores, restaurants), 27.4% had a traffic calming feature (e.g., speed humps), and 53.2% had at least some street lighting. Several features were less prevalent on residential streets compared with commercial streets, including transit stops, sidewalks, destinations, and street lighting (P < .01). CONCLUSIONS: Across the USVI, community and street-scale features supportive of walking were uncommon. Improving community and street-scale design in the USVI, particularly in residential areas, could increase physical activity by enhancing walkability and therefore improve public health. These data can be used to inform community planning in the USVI.

Pelvic orientation for total hip arthroplasty in lateral decubitus: can it be accurately measured?

INTRODUCTION: During total hip arthroplasty (THA), accurately predicting acetabular cup orientation remains a key challenge, in great part because of uncertainty about pelvic orientation. This pilot study aimed to develop and validate a technique to measure pelvic orientation; establish its accuracy in the location of anatomical landmarks and subsequently; investigate if limb movement during a simulated surgical procedure alters pelvic orientation. METHODS: The developed technique measured 3-D orientation of an isolated Sawbone pelvis, it was then implemented to measure pelvic orientation in lateral decubitus with post-THA patients (n = 20) using a motion capture system. RESULTS: Orientation of the isolated Sawbone pelvis was accurately measured, demonstrated by high correlations with angular data from a coordinate measurement machine; R-squared values close to 1 for all pelvic axes. When applied to volunteer subjects, largest movements occurred about the longitudinal pelvic axis; internal and external pelvic rotation. Rotations about the anteroposterior axis, which directly affect inclination angles, showed >75% of participants had movement within ±5° of neutral, 0°. CONCLUSIONS: The technique accurately measured orientation of the isolated bony pelvis. This was not the case in a simulated theatre environment. Soft tissue landmarks were difficult to palpate repeatedly. These findings have direct clinical relevance, landmark registration in lateral decubitus is a potential source of error, contributing here to large ranges in measured movement. Surgeons must be aware that present techniques using bony landmarks to reference pelvic orientation for cup implantation, both computer-based and mechanical, may not be sufficiently accurate.

Discovery of filarial nematode DNA in Amblyomma americanum in Northern Virginia.

Ticks collected in 2011 were screened for the presence of filarial nematode genetic material, and positive samples were sequenced for analysis. Monanema-like filarial nematode DNA was recently discovered in Amblyomma americanum in northern Virginia, marking the first time genetic material from this parasite has been discovered in ticks in the state. Phylogenetic analysis revealed that this material was directly related to a previously discovered filarial nematode in A. americanum populations in Maryland as well as recently identified parasites in Ixodes scapularis from southern Connecticut. Further study is warranted to visually confirm the presence of these nematodes, characterize their distribution, and determine if these ticks are intermediate hosts.

Patients' perception of leg length discrepancy post total hip arthroplasty.

Perception of a leg length discrepancy post total hip arthroplasty (THA) is one of the most common sources of patient dissatisfaction and can have a direct influence on the considered success of the operation.This research examined postoperative perception of imposed limb discrepancies in a group of THA patients compared to a group of participants with no previous hip surgery. Two subgroups of THA patients were involved: those who did not perceive a difference in limb length following THA and those that did.Discrepancies were imposed in 2.5 mm increments. For discrepancies ≥5 mm, a significant number of participants were aware of a difference (74%). There was no significant difference in perception of imposed discrepancies between THA patients and participants with no previous hip surgery. THA patients who perceived a difference in their limb lengths postoperatively had significantly worse pain and oxford scores when compared to THA patients who perceived their limb lengths to be equal. Knowing the boundaries between LLDs that go undetected and those that patients are aware of could guide surgeons when evaluating the balance between correct soft tissue tension and the resulting unequal leg length. From these findings, discrepancies >5 mm are likely to be perceived. Whether this perception would lead directly to a negative outcome score and patient dissatisfaction is more complex to project and likely to be patient specific. Intraoperative methods to aid the controlled positioning of implanted components could help maintain and restore leg length to within an acceptable amount that patients cannot perceive.

Critical evaluation of pulse-echo ultrasonic test method for the determination of setting and mechanical properties of acrylic bone cement: influence of mixing technique.

Currently there is no reliable objective method to quantify the setting properties of acrylic bone cements within an operating theatre environment. Ultrasonic technology can be used to determine the acoustic properties of the polymerising bone cement, which are linked to material properties and provide indications of the physical and chemical changes occurring within the cement. The focus of this study was the critical evaluation of pulse-echo ultrasonic test method in determining the setting and mechanical properties of three different acrylic bone cement when prepared under atmospheric and vacuum mixing conditions. Results indicated that the ultrasonic pulse-echo technique provided a highly reproducible and accurate method of monitoring the polymerisation reaction and indicating the principal setting parameters when compared to ISO 5833 standard, irrespective of the acrylic bone cement or mixing method used. However, applying the same test method to predict the final mechanical properties of acrylic bone cement did not prove a wholly accurate approach. Inhomogeneities within the cement microstructure and specimen geometry were found to have a significant influence on mechanical property predictions. Consideration of all the results suggests that the non-invasive and non-destructive pulse-echo ultrasonic test method is an effective and reliable method for following the full polymerisation reaction of acrylic bone cement in real-time and then determining the setting properties within a surgical theatre environment. However the application of similar technology for predicting the final mechanical properties of acrylic bone cement on a consistent basis may prove difficult.

Spotted fever group rickettsiae in multiple hard tick species from Fairfax County, Virginia.

Spotted fever group rickettsiosis (SFGR) is a potentially fatal disease that has displayed increasing incidence in the United States in recent years. The most well-known and severe type of this disease is Rocky Mountain spotted fever, but there are other mild forms that occur. Recently, human infection with Rickettsia parkeri has been reported and linked with the tick Amblyomma maculatum. In 2010, a population of R. parkeri-infected A. maculatum was discovered in Fairfax County, Virginia, leading to increased surveillance of tick species. In this study, we report the presence of R. parkeri in Rhipicephalus sanguineus, Haemaphysalis leporispalustris, and Dermacentor variabilis in Fairfax County. R. parkeri was discovered in two Rh. sanguineus, one H. leporispalustris, and 17 D. variabilis. These findings suggest that spillover infections of R. parkeri may be occurring in tick species not typically associated with this pathogen; however, vector competence studies need to be conducted to determine if these tick species can serve as potential vectors for human SFGR.

Experimental and computational approach investigating burst fracture augmentation using PMMA and calcium phosphate cements.

The aim of the study was to use a computational and experimental approach to evaluate, compare and predict the ability of calcium phosphate (CaP) and poly (methyl methacrylate) (PMMA) augmentation cements to restore mechanical stability to traumatically fractured vertebrae, following a vertebroplasty procedure. Traumatic fractures (n = 17) were generated in a series of porcine vertebrae using a drop-weight method. The fractured vertebrae were imaged using µCT and tested under axial compression. Twelve of the fractured vertebrae were randomly selected to undergo a vertebroplasty procedure using either a PMMA (n = 6) or a CaP cement variation (n = 6). The specimens were imaged using µCT and re-tested. Finite element models of the fractured and augmented vertebrae were generated from the µCT data and used to compare the effect of fracture void fill with augmented specimen stiffness. Significant increases (p < 0.05) in failure load were found for both of the augmented specimen groups compared to the fractured group. The experimental and computational results indicated that neither the CaP cement nor PMMA cement could completely restore the vertebral mechanical behavior to the intact level. The effectiveness of the procedure appeared to be more influenced by the volume of fracture filled rather than by the mechanical properties of the cement itself.

A low-cost solution for the restoration of femoral head centre during total hip arthroplasty.

Restoration of joint centre during total hip arthroplasty is critical. While computer-aided navigation can improve accuracy during total hip arthroplasty, its expense makes it inaccessible to the majority of surgeons. This article evaluates the use, in the laboratory, of a calliper with a simple computer application to measure changes in femoral head centres during total hip arthroplasty. The computer application was designed using Microsoft Excel and used calliper measurements taken pre- and post-femoral head resection to predict the change in head centre in terms of offset and vertical height between the femoral head and newly inserted prosthesis. Its accuracy was assessed using a coordinate measuring machine to compare changes in preoperative and post-operative head centre when simulating stem insertion on 10 sawbone femurs. A femoral stem with a modular neck was used, which meant nine possible head centre configurations were available for each femur, giving 90 results. The results show that using this technique during a simulated total hip arthroplasty, it was possible to restore femoral head centre to within 6 mm for offset (mean 1.67 ± 1.16 mm) and vertical height (mean 2.14 ± 1.51 mm). It is intended that this low-cost technique be extended to inform the surgeon of a best-fit solution in terms of neck length and neck type for a specific prosthesis.

Development of calcium phosphate cement for the augmentation of traumatically fractured porcine specimens using vertebroplasty.

The study aim was to develop and apply an experimental technique to determine the biomechanical effect of polymethylmethacrylate (PMMA) and calcium phosphate (CaP) cement on the stiffness and strength of augmented vertebrae following traumatic fracture. Twelve burst type fractures were generated in porcine three-vertebra segments. The specimens were randomly split into two groups (n=6), imaged using microCT and tested under axial loading. The two groups of fractured specimens underwent a vertebroplasty procedure, one group was augmented with CaP cement designed and developed at Queen's University Belfast. The other group was augmented with PMMA cement (WHW Plastics, Hull, UK). The specimens were imaged and re-tested . An intact single vertebra specimen group (n=12) was also imaged and tested under axial loading. A significant decrease (p<0.01) was found between the stiffness of the fractured and intact groups, demonstrating that the fractures generated were sufficiently severe, to adversely affect mechanical behaviour. Significant increase (p<0.01) in failure load was found for the specimen group augmented with the PMMA cement compared to the pre-augmentation group, conversely, no significant increase (p<0.01) was found in the failure load of the specimens augmented with CaP cement, this is attributed to the significantly (p<0.05) lower volume of CaP cement that was successfully injected into the fracture, compared to the PMMA cement. The effect of the percentage of cement fracture fill, cement modulus on the specimen stiffness and ultimate failure load could be investigated further by using the methods developed within this study to test a more injectable CaP cement.

A novel device to measure acetabular inclination with patients in lateral decubitus.

The ability to measure acetabular cup orientation accurately during total hip arthroplasty represents a significant challenge. The aim of this research was to develop and evaluate a novel low cost mechanical device for measuring operative acetabular inclination. Cup implantation was simulated in two trials using the novel device: firstly involving surgeons and engineers orientating acetabular cups with sawbone pelves at a range of inclination angles (20°-55° in 5° increments); secondly in a simulated intra-operative scenario with surgeons. Target angles were compared with achieved angles and deviations from desired angles were recorded. In addition, all participants orientated cups under the same conditions using two other techniques: freehand and with a propriatory Mechanical Alignment Guide. In the first trial, the mean errors (deviations) using freehand technique, the mechanical alignment guide and the new device were 5.2° +/- 4.3° (range 0.1-22.0), 3.6° +/- 3.9° (range 0.1°-33.6°) and 0.5° +/- 0.4° (range 0.0-1.9) respectively. In the second trial, the mean error for freehand technique, mechanical alignment guide and the new device were 6.2° +/- 4.2° (range 0.2-18.2), 3.8° +/- 3.3° (range 0.0-19.1) and 0.6° +/- 0.5° (range 0.0-1.8) respectively. The new device has the potential to allow the surgeon to choose and record operative inclination accurately during total hip arthroplasty in the lateral decubitus position.

The potential of electron beam radiation for simultaneous surface modification and bioresorption control of PLLA.

Bioresorbable polymers have been widely investigated as materials exhibiting significant potential for successful application in the fields of tissue engineering and drug delivery. Further to the ability to control degradation, surface engineering of polymers has been highlighted as a key method central to their development. Previous work has demonstrated the ability of electron beam (e-beam) technology to control the degradation profiles and bioresorption of a number of commercially relevant bioresorbable polymers (poly-l-lactic acid (PLLA), L-lactide/DL-lactide co-polymer (PLDL) and poly(lactic-co-glycolic acid (PLGA)). This work investigates the further potential of e-beam technology to impart added biofunctionality through the manipulation of polymer (PLLA) surface properties. PLLA samples were subjected to e-beam treatments in air, with varying beam energies and doses. Surface characterization was then performed using contact angle analysis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and atomic force microscopy. Results demonstrated a significant increase in surface wettability post e-beam treatment. In correlation with this, XPS data showed the introduction of oxygen-containing functional groups to the surface of PLLA. Raman spectroscopy indicated chain scission in the near surface region of PLLA (as predicted). However, e-beam effects on surface properties were not shown to be dependent on beam energy or dose. E-beam irradiation did not seem to affect the surface roughness of PLLA as a direct consequence of the treatment.

Development of a bovine collagen-apatitic calcium phosphate cement for potential fracture treatment through vertebroplasty.

The aim of this study was to examine the potential of incorporating bovine fibres as a means of reinforcing a typically brittle apatite calcium phosphate cement for vertebroplasty. Type I collagen derived from bovine Achilles tendon was ground cryogenically to produce an average fibre length of 0.96±0.55 mm and manually mixed into the powder phase of an apatite-based cement at 1, 3 or 5 wt.%. Fibre addition of up to 5 wt.% had a significant effect (P ≤ 0.001) on the fracture toughness, which was increased by 172%. Adding ≤ 1 wt.% bovine collagen fibres did not compromise the compressive properties significantly, however, a decrease of 39-53% was demonstrated at ≥ 3wt.% fibre loading. Adding bovine collagen to the calcium phosphate cement reduced the initial and final setting times to satisfy the clinical requirements stated for vertebroplasty. The cement viscosity increased in a linear manner (R²=0.975) with increased loading of collagen fibres, such that the injectability was found to be reduced by 83% at 5 wt.% collagen loading. This study suggests for the first time the potential application of a collagen-reinforced calcium phosphate cement as a viable option in the treatment of vertebral fractures, however, issues surrounding efficacious cement delivery need to be addressed.

Through-thickness control of polymer bioresorption via electron beam irradiation.

Predicable and controlled degradation is not only central to the accurate delivery of bioactive agents and drugs, it also plays a vital role in key aspects of bone tissue engineering. The work addressed in this paper investigates the utilisation of e-beam irradiation in order to achieve a controlled (surface) degradation profile. This study focuses on the modification of commercially and clinically relevant materials, namely poly(L-lactic acid) (PLLA), poly(L-lactide-hydroxyapatite) (PLLA-HA), poly(L-lactide-glycolide) co-polymer (PLG) and poly(L-lactide-DL-lactide) co-polymer (PLDL). Samples were subjected to irradiation treatments using a 0.5MeV electron beam with delivered surface doses of 150 and 500 kGy. In addition, an acrylic attenuation shield was used for selected samples to control the penetration of the e-beam. E-beam irradiation induced chain scission in all polymers, as characterized by reduced molecular weights and glass transition temperatures (T(g)). Irradiation not only produced changes in the physical properties of the polymers but also had associated effects on surface erosion of the materials during hydrolytic degradation. Moreover, the extent to which both mechanical and hydrolytic degradation was observed is synonymous with the estimated penetration of the beam (as controlled by the employment of an attenuation shield).

Mechanism of loosening of the Souter-Strathclyde total elbow replacement evidence from revision surgery.

Nine Souter-Strathclyde humeral and ulnar components retrieved from revision surgery for aseptic loosening were examined macro- and microscopically. The wear patterns were compared and photographed. Humeral components demonstrated no evidence of wear. All ulnar components exhibited similar wear patterns. Six of the nine exhibited macroscopic evidence taking the form of deep linear grooves on either the medial or lateral articulating surfaces. Microscopic examinations revealed wear on all nine, exhibited as disruption of the polyethylene machining lines on the articular surfaces, but almost complete preservation on the central gliding ridge. We believe our observations are explained by 'rocking' of the humeral component on the ulnar as a result of the congruent surfaces of the Souter-Strathclyde prosthesis, which resist rotational and translational movements, characteristic of the normal elbow.