Multicentre evaluation of Erytra Eflexis®, a benchtop fully automated analyser with a compact design for routine use in blood transfusion laboratory

OBJECTIVES

Evaluation of the compact benchtop Erytra Eflexis® automated analyser was performed at three health centres representing a range of routine transfusion workload.

BACKGROUND

Automation instruments with the simplicity and flexibility adequate for small- to mid-sized blood transfusion services are an unmet need.

METHODS

Performance in pre-transfusion testing (2109 ABO/D, 382 Rh/K phenotype, 2001 antibody screening, 113 antibody identification, 151 DAT, 88 extended phenotype; 655 cross matching) in comparison to Erytra® as reference device was assessed. Throughput [time to first result (TTFR), final turn-around time (TAT), processing rate] was calculated; usability and adaptability in laboratory practice under routine and with emergency samples were surveyed.

RESULTS

Agreement between systems was 99·8% (11/5499 test discrepancies, all due to weak/doubtful positive reactions). Erytra Eflexis produced six true positives (two Rh/D, two B positives, two screening), four false positives (three screening and one cross matching) and one false negative (screening). Processing of eight routine samples with the Erytra Eflexis for ABO/Rh(D) and screening took 34-38 min and 32-37 min, respectively, independent of the simultaneous processing of a STAT sample, whether or not the incubator for STAT was reserved. In this scenario, a STAT sample requested within 2 min after the routine load was processed in 14-26 min. Processing rate tended to stabilise and optimise in the larger workloads, particularly in ABO/Rh(D)/K cards (16·7, 18 and 19·5 results/h for 10, 15 and 24 specimens, respectively).

CONCLUSION

Erytra Eflexis analyser was found to be reliable and suitable for pre-transfusion routine tests performed in a small-/medium-sized blood transfusion laboratory.

Experimental Studies of Nonabsorbable Polymeric Surgical Clips for Use in Urologic Laparoscopy

Objective: This study aimed to compare the stability of the Click'aV^® (Grena^®), Click'aV plus (Grena), and Hem-o-lok^® (Weck^®, Teleflex^®) polymer clips and the evaluation of the clips stability on a complete porcine artery. Materials and Methods: A dynamometer with a custom support and clamp unit was used. The crank gradually increased the tension force being applied on the clip via the suture. Different directions for the application of the force were tested. The highest force before the start of slipping the suture was noted. The procedure was repeated three times for each ligating clip. Results: For transverse stability, the "XL-size" Grena Click'aV Plus required preventing slippage at a greater force compared to the Hem-o-lok (p = 0.0071). No significant differences found statistically between the Grena Click'aV and Hem-o-lok clips (p = 0.1). For longitudinal stability, the Hem-o-lok required a significantly higher force to be opened compared to the Click'aV (p = 0.0036), but no statistically significant difference was found compared to the Click'aV Plus (p = 0.1). Concerning porcine artery stability, the artery slipped through the Click'aV clip in both measurements at a force of 10.2 and 9.4 N. In contrast, the arteries were cut in all measurements using the Click'aV Plus and the Hem-o-lok clips at forces of 11.8 and 12.8 N and 12.9 and 14.2 N, respectively. None of the clips leaked with up to 300 mm Hg of intra-arterial pressure applied to porcine renal arteries. Conclusions: The Grena Click'aV Plus clip has similar performance to the Hem-o-lok clip, and this clip can be equally useful for ligating vessels in laparoscopic urologic surgeries. We believe, from our findings in this study as well as those from other reports, that vascular clips applied properly by experienced surgeons provide a safe, reliable, and considerable cost-saving option for vascular control in urologic laparoscopic surgery.

Applications of Spatial Light Modulators in Raman Spectroscopy

Advances in consumer display screen technologies have historically been adapted by researchers across the fields of optics as they can be used as electronically controlled spatial light modulators (SLMs) for a variety of uses. The performance characteristics of such SLM devices based on liquid crystal (LC) and digital micromirror device (DMD) technologies, in particular, has developed to the point where they are compatible with increasingly sensitive instrumental applications, for example, Raman spectroscopy. Spatial light modulators provide additional flexibility, from modulation of the laser excitation (including multiple laser foci patterns), manipulation of microscopic samples (optical trapping), or selection of sampling volume (adaptive optics or spatially offset Raman spectroscopy), to modulation in the spectral domain for high-resolution spectral filtering or multiplexed/compressive fast detection. Here, we introduce the benefits of different SLM devices as a part of Raman instrumentation and provide a variety of recent example applications which have benefited from their incorporation into a Raman system.

A Prototype to Detect the Alcohol Content of Beers Based on an Electronic Nose

Due to the emergence of new microbreweries in the Brazilian market, there is a need to construct equipment to quickly and accurately identify the alcohol content in beverages, together with a reduced marketing cost. Towards this purpose, the electronic noses prove to be the most suitable equipment for this situation. In this work, a prototype was developed to detect the concentration of ethanol in a high spectrum of beers presents in the market. It was used cheap and easy-to-acquire 13 gas sensors made with a metal oxide semiconductor (MOS). Samples with 15 predetermined alcohol contents were used for the training and construction of the models. For validation, seven different commercial beverages were used. The correlation (R²) of 0.888 for the MLR (RMSE = 0.45) and the error of 5.47% for the ELM (RMSE = 0.33) demonstrate that the equipment can be an effective tool for detecting the levels of alcohol contained in beverages.

Capacitive Impedance Measurement: Dual-frequency Approach

The most widely used technique for measuring capacitive impedances (or complex electrical permittivity) is to apply a frequency signal to the sensor and measure the amplitude and phase of the output signal. The technique, although efficient, involves high-speed circuits for phase measurement, especially when the medium under test has high conductivity. This paper presents a sensor to measure complex electrical permittivity based on an alternative approach to amplitude and phase measurement: The application of two distinct frequencies using a current-to-voltage converter circuit based in a transimpedance amplifier, and an 8-bit microcontroller. Since there is no need for phase measurement and the applied frequency is lower compared to the standard method, the circuit presents less complexity and cost than the traditional technique. The main advance presented in this work is the use of mathematical modeling of the frequency response of the circuit to make it possible for measuring the dielectric constant using a lower frequency than the higher cut-off frequency of the system, even when the medium under test has high conductivity (tested up to 1220 μS/cm). The proposed system caused a maximum error of 0.6% for the measurement of electrical conductivity and 2% for the relative dielectric constant, considering measurement ranges from 0 to 1220 μS/cm and from 1 to 80, respectively.

Fusion Rates of Lateral Lumbar Interbody Fusion Using Recombinant Human Bone Morphogenetic Protein-2

STUDY DESIGN

Retrospective observational case series.

OBJECTIVES

Lateral lumbar interbody fusion (LLIF) has been widely performed with recombinant human bone morphogenetic protein-2 (rhBMP-2), but the fusion rates using this graft alternative have not been well studied. We aimed to evaluate fusion rates in 1- and 2-level LLIF with rhBMP-2 and their relationship with fixation, as well as rates of BMP-related complications.

METHODS

Institutional review board (IRB)-approved spine registry cohort of 93 patients who underwent LLIF with rhBMP-2 (71 one-level cases and 22 two-level cases). Minimum 1-year clinical follow-up and computed tomography (CT) scan for fusion assessment. Postoperative CT scans were used to evaluate the rate of fusion in all patients. Instrumentation and complications were collected from chart and imaging review.

RESULTS

Average age was 65 years (67% female). For 1-level cases, 92% (65/71) had complete fusion and 8% (6/71) had either incomplete or indeterminate fusion. Three of the 6 patients who had incomplete or indeterminate fusion had bilateral pedicle screw instrumentation, 1 patient had unilateral posterior fixation, and 2 had no fixation. In 2-level cases, 86% (19/22) had complete fusion and 14% (3/22) had either incomplete or indeterminate fusion. The 3 patients who had incomplete or indeterminate fusion did not have fixation.

CONCLUSION

Interbody fusion rates with rhBMP-2 via LLIF was 92% in 1-level cases and 86% in 2-level cases, indicating that rhBMP-2 may be used as a viable graft alternative to allograft options for LLIF. Higher rates of pseudarthrosis occurred when not using fixation.

Performance evaluation of the 5-Ring GE Discovery MI PET/CT system using the national electrical manufacturers association NU 2-2012 Standard

The GE Discovery MI PET/CT system has a modular digital detector design allowing three, four, or five detector block rings that extend the axial field-of-view (FOV) from 15 to 25 cm in 5 cm increments. This study investigated the performance of the 5-ring system and compared it to 3- and 4-ring systems; the GE Discovery IQ system that uses conventional photomultiplier tubes; and the GE Signa PET/MR system that has a reduced transaxial FOV.

METHODS

PET performance was evaluated at three different institutions. Spatial resolution, sensitivity, counting rate performance, accuracy, and image quality were measured in accordance with National Electrical Manufacturers Association NU 2-2012 standards. The mean energy resolution, mean timing resolution, and PET/CT subsystem alignment were also measured. Phantoms were used to determine the effects of varying acquisition time and reconstruction parameters on image quality. Retrospective patient scans were reconstructed with various scan durations to evaluate the impact on image quality.

RESULTS

Results from all three institutions were similar. Radial/tangential/axial full width at half maximum spatial resolution measurements using the filtered back projection algorithm were 4.3/4.3/5.0 mm, 5.5/4.6/6.5 mm, and 7.4/5.0/6.6 mm at 1, 10, and 20 cm from the center of the FOV, respectively. Measured sensitivity at the center of the FOV (20.84 cps/kBq) was significantly higher than systems with reduced axial FOV. The peak noise-equivalent counting rate was 266.3 kcps at 20.8 kBq/ml, with a corresponding scatter fraction of 40.2%. The correction accuracy for count losses up to the peak noise-equivalent counting rate was 3.6%. For the 10-, 13-, 17-, 22-, 28-, and 37-mm spheres, contrast recoveries in the image quality phantom were measured to be 46.2%, 54.3%, 66.1%, 71.1%, 85.3%, and 89.3%, respectively. The mean energy and timing resolution were 9.55% and 381.7 ps, respectively. Phantom and patient images demonstrated excellent image quality, even at short acquisition times or low injected activity.

CONCLUSION

Compared to other PET/CT models, the extended axial FOV improved the overall PET performance of the 5-ring GE Discovery MI scanner. This system offers the potential to reduce scan times or injected activities through increased sensitivity.

Extrusion of Debris from Curved Root Canals Instrumented up to Different Working Lengths Using Different Reciprocating Systems

INTRODUCTION

The aim of this study was to evaluate the extrusion of debris associated with the use of the Reciproc (VDW GmbH, Munich, Germany) and WaveOne Gold (Dentsply Maillefer, Ballaigues, Switzerland) reciprocating systems in curved canals instrumented up to different working lengths (WLs).

METHODS

Sixty mesial roots of extracted mandibular first molars with mesiobuccal canals having curvatures between 10° and 20° and independent foramina were randomly distributed into 4 experimental groups (n = 15) according to WL and the instrumentation system used: RC0, Reciproc and WL at the apical foramen; RC1, Reciproc and WL at 1 mm short of the apical foramen; WOG0, WaveOne Gold and WL at the apical foramen; and WOG1, WaveOne Gold and WL at 1 mm short of the apical foramen. The canals were irrigated with double-distilled water throughout the preparation. Each root was fit into an Eppendorf tube to collect the debris extruded through the foramen during instrumentation. After instrumentation, the roots were removed from the tubes, and the weight of the debris was obtained by subtracting the initial weight of the tubes from their final weight. The data were submitted to the analysis of variance parametric test complemented by the Tukey test.

RESULTS

No statistically significant difference was observed between the 4 experimental groups regarding the amount of debris extruded (P > .05).

CONCLUSIONS

The 2 reciprocating systems tested were associated with similar amounts of apically extruded debris, regardless of the working length used in the instrumentation.

Comparative analysis of torque and apical force to assess the cutting behaviour of ProTaper Next and ProTaper Universal endodontic instruments

This study assessed the cutting properties of two Nickel Titanium file systems with different designs and manufacturing materials. ProTaper Next X1 and X2 (PTN; Dentsply Sirona) and ProTaper Universal S2 and F1 (PTU; Dentsply Sirona) instruments were employed. The cutting parameters, that is torque and apical forces, were determined using a specially designed bench-testing machine. Dimensional and geometric parameters were considered to evaluate the results. The average maximum torque values showed statistically significant differences (P < 0.05) among all instruments. Apical force for PTN X2 and PTU F1 instruments initially decreased and then experienced a rapid increase in the last 2 mm of the canal. For PTN X1 and PTU S2, apical force increased during the entire test. When compared to PTU files, PTN required higher torque and apical forces during the shaping procedure. The results lead us to conclude that PTN instruments demonstrated a lower cutting efficiency than PTU.

Multi-Phase Flow Metering in Offshore Oil and Gas Transportation Pipelines: Trends and Perspectives

Multi-phase flow meters are of huge importance to the offshore oil and gas industry. Unreliable measurements can lead to many disadvantages and even wrong decision-making. It is especially important for mature reservoirs as the gas volume fraction and water cut is increasing during the lifetime of a well. Hence, it is essential to accurately monitor the multi-phase flow of oil, water and gas inside the transportation pipelines. The objective of this review paper is to present the current trends and technologies within multi-phase flow measurements and to introduce the most promising methods based on parameters such as accuracy, footprint, safety, maintenance and calibration. Typical meters, such as tomography, gamma densitometry and virtual flow meters are described and compared based on their performance with respect to multi-phase flow measurements. Both experimental prototypes and commercial solutions are presented and evaluated. For a non-intrusive, non-invasive and inexpensive meter solution, this review paper predicts a progress for virtual flow meters in the near future. The application of multi-phase flows meters are expected to further expand in the future as fields are maturing, thus, efficient utilization of existing fields are in focus, to decide if a field is still financially profitable.

The Single Particles, Clusters and Biomolecules and Serial Femtosecond Crystallography instrument of the European XFEL: initial installation

The European X-ray Free-Electron Laser (FEL) became the first operational high-repetition-rate hard X-ray FEL with first lasing in May 2017. Biological structure determination has already benefitted from the unique properties and capabilities of X-ray FELs, predominantly through the development and application of serial crystallography. The possibility of now performing such experiments at data rates more than an order of magnitude greater than previous X-ray FELs enables not only a higher rate of discovery but also new classes of experiments previously not feasible at lower data rates. One example is time-resolved experiments requiring a higher number of time steps for interpretation, or structure determination from samples with low hit rates in conventional X-ray FEL serial crystallography. Following first lasing at the European XFEL, initial commissioning and operation occurred at two scientific instruments, one of which is the Single Particles, Clusters and Biomolecules and Serial Femtosecond Crystallography (SPB/SFX) instrument. This instrument provides a photon energy range, focal spot sizes and diagnostic tools necessary for structure determination of biological specimens. The instrumentation explicitly addresses serial crystallography and the developing single particle imaging method as well as other forward-scattering and diffraction techniques. This paper describes the major science cases of SPB/SFX and its initial instrumentation - in particular its optical systems, available sample delivery methods, 2D detectors, supporting optical laser systems and key diagnostic components. The present capabilities of the instrument will be reviewed and a brief outlook of its future capabilities is also described.

SwissFEL Aramis beamline photon diagnostics. Erratum

The list of authors in the paper by Juranić et al. (2018) [J. Synchrotron Rad. 25, 1238-1248] is corrected.

Evaluation of Wireless Phosphine Sensors for Monitoring Fumigation Gas in Wheat Stored in Farm Bins

Fumigation of grain bins with phosphine tablets is one method of insect control for stored products. Monitoring the concentration of the toxic gas at many locations over several days for a given structure or container can be challenging. In this study, a commercially-available system that wirelessly measures phosphine was evaluated in small-scale and large-scale tests. Small-scale testing was performed to study the repeatability and accuracy of the sensors. The wireless sensors were within 30 ppm of each other, over a range of 700 ppm phosphine. Large-scale testing evaluated the system during the fumigation of wheat stored in 7 m diameter, 120 metric ton, steel grain bins. As a reference, monitoring lines were distributed at several positions and depths in the bin in order to sample phosphine gas concentrations. A series of three fumigation trials were performed, with each lasting for over six days. The wireless devices collected local phosphine concentrations and temperatures every two hours without assistance from personnel. Although the fumigation trials were significantly different in terms of patterns in gas concentration over time, the two sampling methods gave similar trendlines. However, the automated data provided a more detailed picture of the fumigation process. This information may help fumigation managers to better evaluate fumigations and assure successful insect control.

A Microwave Polarimeter Demonstrator for Astronomy with Near-Infra-Red Up-Conversion for Optical Correlation and Detection

This paper presents a 10 to 20 GHz bandwidth microwave polarimeter demonstrator, based on the implementation of a near-infra-red frequency up-conversion stage that allows both the optical correlation, when operating as a synthesized-image interferometer, and signal detection, when operating as a direct-image instrument. The proposed idea is oriented towards the implementation of ultra-sensitive instruments presenting several dozens or even thousands of microwave receivers operating in the lowest bands of the cosmic microwave background. In this work, an electro-optical back-end module replaces the usual microwave detection stage with Mach–Zehnder modulators for the frequency up-conversion, and an optical stage for the signals correlation and detection at near-infra-red wavelengths (1550 nm). As interferometer, the instrument is able to correlate the signals of large-format instruments, while operating as a direct imaging instrument also presents advantages in terms of the possibility of implementing the optical back end by means of photonic integrated circuits to achieve reductions in cost, weight, size, and power consumption. A linearly polarized input wave, with a variable polar angle, is used as a signal source for laboratory tests. The receiver demonstrator has proved its capabilities of being used as a new microwave-photonic polarimeter for the study of the lowest bands of cosmic microwave background.

Cystoscopically Guided Repair of a Posterior Perforation of Augmented Bladder

Background: Augmentation cystoplasty for the management of neurogenic bladder is one of the mainstays of pediatric urology. This procedure has multiple well-known complications. The most dangerous of these complications is bladder perforation, which has a mortality rate of 23% to 25% in large part caused by delayed presentation and sepsis. This case report discusses a novel method for identifying the perforation using endourologic techniques to allow for easier repair.

Case Presentation: A 24-year-old woman with a history of spina bifida s/p augmentation cystoplasty with appendicovesicostomy and rectus fascia bladder neck sling 5 years ago presented to the emergency department with a 2-day history of decreased oral intake, nausea, vomiting, fevers, diffuse abdominal pain, and distention. She was found on CT cystogram to have a contrast extravasation from the posterior-dependent portion of the bladder and a large retrovesical fluid collection. On exploratory laparotomy, a leak from the posterior portion of the bladder was confirmed. Owing to the conditions in the abdomen and the patient's obese body habitus, the perforation was very difficult to view. A 17F rigid cystoscope was utilized and the perforation was identified on the posterior inferior portion of the bladder at the anastomotic line. A wire was passed through the perforation into the abdomen where it was seen and an 18F council catheter was then placed in an antegrade manner from the abdomen. Placement of the catheter and inflation of the balloon did not cause any additional apparent damage to the bladder mucosa. With the catheter on traction, the dependent bladder could be pulled back into the operative field, allowing complete observation of the defect for water-tight two-layer closure.

Conclusion: Bladder perforation after augmentation cystoplasty is a potentially life-threatening complication that can be difficult to repair. This article serves to present a novel way to identify and facilitate repair of the defect intraoperatively using endourologic principles for a posterior defect.

A Gas-Phase Reaction Cell for Modern Atom Probe Systems

In this work, we demonstrate a new system for the examination of gas interactions with surfaces via atom probe tomography. This system provides capability of examining the surface and subsurface interactions of gases with a wide range of specimens, as well as a selection of input gas types. This system has been primarily developed to aid the investigation of hydrogen interactions with metallurgical samples, to better understand the phenomenon of hydrogen embrittlement. In its current form, it is able to operate at pressures from 10-6 to 1000 mbar (abs), can use a variety of gasses, and is equipped with heating and cryogenic quenching capabilities. We use this system to examine the interaction of hydrogen with Pd, as well as the interaction of water vapor and oxygen in Mg samples.

Alteplase Instillation for Upper Urinary Tract Clot Dissolution

Background: We report the first case of instillation of alteplase, a tissue plasminogen activator, to dissolve occlusive upper urinary tract blood clot. Case Presentation: A 67-year-old Caucasian man with a solitary kidney became dialysis dependent because of upper urinary tract clot obstruction after ureteral stent placement for obstructing ureterolithiasis. After failure of more conservative measures, 10 mg of alteplase was instilled through nephrostomy tube daily for 2 consecutive days 30 minutes before manual irrigation with physiologic saline. After alteplase instillation, the occlusive blood clot dissolved with rapid improvement in urinary output and creatinine. Conclusions: Alteplase instillation through nephrostomy tube is a viable option to dissolve obstructing upper urinary tract blood clots.

A versatile liquid-jet setup for the European XFEL

The SPB/SFX instrument of the European XFEL provides unique possibilities for high-throughput serial femtosecond crystallography. This publication presents the liquid-jet sample delivery setup of this instrument. The setup is compatible with state-of-the-art gas dynamic virtual nozzle systems as well as high-viscosity extruders and provides space and flexibility for other liquid injection devices and future upgrades. The liquid jets are confined in a differentially pumped catcher assembly and can be replaced within a couple of minutes through a load-lock. A two-microscope imaging system allows visual control of the jets from two perspectives.

Instrumentation complication rates following spine surgery: a report from the Scoliosis Research Society (SRS) morbidity and mortality database

Background

Objective of this study is to evaluate demographics, risk factors, and incidence of instrumentation related complications (IRC) in spinal surgeries from 2009-2012. The Scoliosis Research Society (SRS) morbidity and mortality (M&M) database has tremendous value in orthopaedic surgery. SRS gathers surgeon-reported complications, including instrumentation failure, visual complications, neurological deficits, infections, and death. Limited literature exists on the incidence of perioperative instrumentation complications in deformity surgery. We utilized the SRS database to evaluate demographics, risk factors, and incidence of IRC in spinal surgeries from 2009-2012.

Methods

The SRS M&M database was queried for IRC in patients undergoing surgery for scoliosis, spondylolisthesis, and kyphosis from 2009-2012. Demographics, comorbidities, diagnoses, curve magnitude, and intraoperative characteristics were analyzed. Intraoperative characteristics included surgical approach, performance of fusion or osteotomy, operative times, blood loss, instrumentation used, and documented instrumentation complication.

Results

A total of 167,972 patients were identified, including 311 IRC. The overall IRC rate was 0.19% (18.5 per 10,000 patients), which decreased significantly from 2009-2012 (0.37% vs. 0.19%, P<0.001). The mean age of patients with IRC was 38.5±25.5 years. Most common comorbidities included hypertension (23.5%), pulmonary disease (13.5%), diabetes (10.6%), smoking (8.7%), and vascular disease (7.1%). IRC occurred in 206 (66.2%) patients with scoliosis, 58 (18.6%) with spondylolisthesis, and 45 (14.5%) with kyphosis. Compared to patients with spondylolisthesis, patients with kyphosis (0.27% vs. 0.11%, P<0.001) and scoliosis (0.21% vs. 0.11%, P<0.001), experienced significantly more IRC. IRC included implant failure (23.3%), migration (28.3%), and malpositioned implants (48.6%). New perioperative neurologic deficits were reported in 146 (46.9%) patients, and 84 (27%) of these implants were removed.

Conclusions

IRC occur in approximately 18.5 per 10,000 deformity patients, with a rate significantly higher in patients with kyphosis. The potentially avoidable occurrence of implant malpositioning represents nearly 50% of these complications. Closer attention to posterior bony anatomy, improved intraoperative imaging with utilization of navigation or robotic guidance may decrease these complications.

Fast beam monitor diamond-based devices for VUV and X-ray synchrotron radiation applications

The improved performance of third-generation light sources and the advent of next-generation synchrotron radiation facilities require the use of extremely precise monitoring of the main photon-beam parameters, such as position, absolute and relative intensity, and temporal structure. These parameters, and associated real-time feedbacks, are fundamental at the beamline control level and at the machine control level, to improve the stability of the photon beams and to provide bunch-to-bunch quantitative information. Fast response time, high radiation hardness and visible-blind response are main features of photon-beam monitors for VUV and X-ray synchrotron radiation beamlines; hence diamond-based detectors are outstanding candidates. Here, results are presented of an extensive measurement campaign aiming at optimizing the capabilities of diamond detectors to discern time structures below the 100 ps timescale. A custom-built device has been fabricated and tested at the Italian Synchrotron Radiation Laboratory Elettra in Trieste. The results obtained show that diamond is an excellent material for ultra-fast photon pulses with picosecond time resolution; finally the possibilities for application at free-electron laser sources are discussed.

In Vivo Translation of the CIRPI System: Revealing Molecular Pathology of Rabbit Aortic Atherosclerotic Plaques

Thin-cap fibroatheroma (TCFA) are the unstable lesions in coronary artery disease that are prone to rupture, resulting in substantial morbidity and mortality worldwide. However, their small size and complex morphologic and biologic features make early detection and risk assessment difficult. We tested our newly developed catheter-based Circumferential-Intravascular-Radioluminescence-Photoacoustic-Imaging (CIRPI) system in vivo to enable detection and characterization of vulnerable plaque structure and biology in rabbit abdominal aorta. Methods: The CIRPI system includes a novel optical probe combining circumferential radioluminescence imaging and photoacoustic tomography (PAT). The probe's CaF₂:Eu-based scintillating imaging window captures radioluminescence images (360° view) of plaques by detecting β-particles during ¹⁸F-FDG decay. A tunable laser-based PAT characterizes tissue constituents of plaque at 7 different wavelengths-540 and 560 nm (calcification), 920 nm (cholesteryl ester), 1040 nm (phospholipids), 1180 nm (elastin/collagen), 1210 nm (cholesterol), and 1235 nm (triglyceride). A single B-scan is concatenated from 330 A-lines captured during a 360° rotation. The abdominal aorta was imaged in vivo in both atherosclerotic rabbits (Watanabe Heritable Hyper Lipidemic [WHHL], 13-mo-old male, n = 5) and controls (New Zealand White, n = 2). Rabbits were fasted for 6 h before 5.55 × 10⁷ Bq (1.5 mCi) of ¹⁸F-FDG were injected 1 h before the imaging procedure. Rabbits were anesthetized, and the right or left common carotid artery was surgically exposed. An 8 French catheter sheath was inserted into the common carotid artery, and a 0.035-cm (0.014-in) guidewire was advanced to the iliac artery, guided by x-ray fluoroscopy. A bare metal stent was implanted in the dorsal abdominal aorta as a landmark, followed by the 7 French imaging catheters that were advanced up to the proximal stent edge. Our CIRPI and clinical optical coherence tomography (OCT) were performed using pullback and nonocclusive flushing techniques. After imaging with the CIRPI system, the descending aorta was flushed with contrast agent, and OCT images were obtained with a pullback speed of 20 mm/s, providing images at 100 frames/s. Results were verified with histochemical analysis. Results: Our CIRPI system successfully detected the locations and characterized both stable and vulnerable aortic plaques in vivo among all WHHL rabbits. Calcification was detected from the stable plaque (540 and 560 nm), whereas TCFA exhibited phospholipids/cholesterol (1040 nm, 1210 nm). These findings were further verified with the clinical OCT system showing an area of low attenuation filled with lipids within TCFA. PAT images illustrated broken elastic fiber/collagen that could be verified with the histochemical analysis. All WHHL rabbits exhibited sparse to severe macrophages. Only 4 rabbits showed both moderate-to-severe level of calcifications and cholesterol clefts. However, all rabbits exhibited broken elastic fibers and collagen deposition. Control rabbits showed normal wall thickness with no presence of plaque tissue compositions. These findings were verified with OCT and histochemical analysis. Conclusion: Our novel multimodality hybrid system has been successfully translated to in vivo evaluation of atherosclerotic plaque structure and biology in a preclinical rabbit model. This system proposed a paradigm shift that unites molecular and pathologic imaging technologies. Therefore, the system may enhance the clinical evaluation of TCFA, as well as expand our understanding of coronary artery disease.

First Human Imaging Studies with the EXPLORER Total-Body PET Scanner

Within the EXPLORER Consortium, the construction of the world's first total-body PET/CT scanner has recently been completed. The 194-cm axial field of view of the EXPLORER PET/CT scanner is sufficient to cover, for the first time, the entire human adult body in a single acquisition in more than 99% of the population and allows total-body pharmacokinetic studies with frame durations as short as 1 s. The large increase in sensitivity arising from total-body coverage as well as increased solid angle for detection at any point within the body allows whole-body ¹⁸F-FDG PET studies to be acquired with unprecedented count density, improving the signal-to-noise ratio of the resulting images. Alternatively, the sensitivity gain can be used to acquire diagnostic PET images with very small amounts of activity in the field of view (25 MBq, 0.7 mCi or less), with very short acquisition times (∼1 min or less) or at later time points after the tracer's administration. We report here on the first human imaging studies on the EXPLORER scanner using a range of different protocols that provide initial evidence in support of these claims. These case studies provide the foundation for future carefully controlled trials to quantitatively evaluate the improvements possible through total-body PET imaging.

A low-cost quantitative continuous measurement of movements in the extremities of people with Parkinson's disease

The assessment of Parkinson's disease currently relies on the history of the present illness, the clinical interview, the physical examination, and structured instruments. Drawbacks to the use of clinical ratings include the reliance on real-time human vision to quantify small differences in motion and significant inter-rater variability due to inherent subjectivity in scoring the procedures. Rating tools are semi-quantitative by design, however, in addition to significant inter-rater variability, there is inherent subjectivity in administering these tools, which are not blinded in clinical settings. Sophisticated systems to quantify movements are too costly to be used by some providers with limited resources. A simple procedure is described to obtain continuous quantitative measurements of movements of people with Parkinson's disease for objective analysis and correlation with visual observation of the movements. •Inexpensive accelerometers are attached to the upper and lower extremities of patients with Parkinson's disease and related conditions to generate a continuous, three-dimensional recorded representation of movements occurring while performing tasks to characterize the deficits of Parkinson's disease.•Movements of the procedure are rated by trained examiners live in real-time and later by videotapes.•The output of the instrumentation can be conveyed to experts for interpretation for diagnostic and therapeutic purposes.

Performance Evaluation of G8, a High-Sensitivity Benchtop Preclinical PET/CT Tomograph

G8 is a benchtop integrated PET/CT scanner dedicated to high-sensitivity and high-resolution imaging of mice. This work characterizes its National Electrical Manufacturers Association NU 4-2008 performance where applicable and also assesses the basic imaging performance of the CT subsystem. Methods: The PET subsystem in G8 consists of 4 flat-panel detectors arranged in a boxlike geometry. Each panel consists of 2 modules of a 26 × 26 pixelated bismuth germanate scintillator array with individual crystals measuring 1.75 × 1.75 × 7.2 mm. The crystal arrays are coupled to multichannel photomultiplier tubes via a tapered, pixelated glass lightguide. A cone-beam CT scanner consisting of a MicroFocus x-ray source and a complementary metal oxide semiconductor detector provides anatomic information. Sensitivity, spatial resolution, energy resolution, scatter fraction, count-rate performance, and the capability of performing phantom and mouse imaging were evaluated for the PET subsystem. Noise, dose level, contrast, and resolution were evaluated for the CT subsystem. Results: With an energy window of 350-650 keV, the peak sensitivity was 9.0% near the center of the field of view. The crystal energy resolution ranged from 15.0% to 69.6% in full width at half maximum (FWHM), with a mean of 19.3% ± 3.7%. The average intrinsic spatial resolution was 1.30 and 1.38 mm FWHM in the transverse and axial directions, respectively. The maximum-likelihood expectation maximization reconstructed image of a point source in air averaged 0.81 ± 0.11 mm FWHM. The peak noise-equivalent count rate for the mouse-sized phantom was 44 kcps for a total activity of 2.9 MBq (78 μCi), and the scatter fraction was 11%. For the CT subsystem, the value of the modulation transfer function at 10% was 2.05 cycles/mm. Conclusion: The overall performance demonstrates that the G8 can produce high-quality images for molecular imaging-based biomedical research.

Microfluidic Analyzer Enabling Quantitative Measurements of Specific Intracellular Proteins at the Single-Cell Level

This paper presents a microfluidic instrument capable of quantifying single-cell specific intracellular proteins, which are composed of three functioning modules and two software platforms. Under the control of a LabVIEW platform, a pressure module flushed cells stained with fluorescent antibodies through a microfluidic module with fluorescent intensities quantified by a fluorescent module and translated into the numbers of specific intracellular proteins at the single-cell level using a MATLAB platform. Detection ranges and resolutions of the analyzer were characterized as 896.78–6.78 × 10⁵ and 334.60 nM for Alexa 488, 314.60–2.11 × 10⁵ and 153.98 nM for FITC, and 77.03–5.24 × 10⁴ and 37.17 nM for FITC-labelled anti-beta-actin antibodies. As a demonstration, the numbers of single-cell beta-actins of two paired oral tumor cell types and two oral patient samples were quantified as: 1.12 ± 0.77 × 10⁶/cell (salivary adenoid cystic carcinoma parental cell line (SACC-83), n_cell = 13,689) vs. 0.90 ± 0.58 × 10⁵/cell (salivary adenoid cystic carcinoma lung metastasis cell line (SACC-LM), n_cell = 15,341); 0.89 ± 0.69 × 10⁶/cell (oral carcinoma cell line (CAL 27), n_cell = 7357) vs. 0.93 ± 0.69 × 10⁶/cell (oral carcinoma lymphatic metastasis cell line (CAL 27-LN2), n_cell = 6276); and 0.86 ± 0.52 × 10⁶/cell (patient I) vs. 0.85 ± 0.58 × 10⁶/cell (patient II). These results (1) validated the developed analyzer with a throughput of 10 cells/s and a processing capability of ~10,000 cells for each cell type, and (2) revealed that as an internal control in cell analysis, the expressions of beta-actins remained stable in oral tumors with different malignant levels.

Therapeutic outcome of spinal implant infections caused by Staphylococcus aureus: A retrospective observational study

Spinal implant infection is a rare but significant complication of spinal fusion surgery, and the most common pathogen is Staphylococcus aureus. It is difficult to treat due to this pathogen's biofilm-forming ability and antibiotic resistance. We evaluated the therapeutic outcome of treatments for S aureus spinal implant infections. We retrospectively reviewed all patients with S aureus spinal implant infections at 11 tertiary-care hospitals over a 9-year period. Parameters predictive of treatment failure and recurrence were analyzed by Cox regression. Of the 102 patients with infections, 76 (75%) were caused by methicillin-resistant S aureus (MRSA) and 51 (50%) were late-onset infections. In all, 83 (81%) patients were managed by debridement, antibiotics, and implant retention (DAIR) and 19 (19%) had their implants removed. The median duration of all antibiotic therapies was 52 days. During a median follow-up period of 32 months, treatment failure occurred in 37 (36%) cases. The median time to treatment failure was 113 days, being <1 year in 30 (81%) patients. DAIR (adjusted hazard ratio [aHR], 6.27; P = .01) and MRSA infection (aHR, 4.07; P = .009) were independently associated with treatment failure. Rifampin-based combination treatments exhibited independent protective effects on recurrence (aHR, 0.23; P = .02). In conclusion, among patients with S aureus spinal implant infections, MRSA and DAIR were independent risk factors for treatment failure, and these risk factors were present in the majority of patients. In this difficult-to-treat population, the overall treatment failure rate was 36%; rifampin may improve the outcomes of patients with S aureus spinal implant infections.

A new methodology for the measurement of the root canal curvature and its 3D modification after instrumentation

OBJECTIVE

In this study, the three-dimensional (3D) modification of root canal curvature was measured, after the application of Reciproc instrumentation technique, by using cone beam computed tomography (CBCT) imaging and a special algorithm developed for the 3D measurement of the curvature of the root canal.

MATERIALS AND METHODS

Thirty extracted upper molars were selected. Digital radiographs for each tooth were taken. Root curvature was measured by using Schneider method and they were divided into three groups, each one consisting of 10 roots, according to their curvature: Group 1 (0°-20°), Group 2 (21°-40°), Group 3 (41°-60°). CBCT imaging was applied to each tooth before and after its instrumentation, and the data were examined by using a specially developed CBCT image analysis algorithm.

RESULTS

The instrumentation with Reciproc led to a decrease of the curvature by 30.23% (on average) in all groups.

CONCLUSIONS

The proposed methodology proved to be able to measure the curvature of the root canal and its 3D modification after the instrumentation.

Ten-year follow-up on adoption of endodontic technology and clinical guidelines amongst Danish general dental practitioners

OBJECTIVE

The aim of this study was to re-assess the adoption of certain endodontic technology and central treatment principles of root canal treatments as advocated by guidelines presented by the European Society of Endodontology.

MATERIAL AND METHODS

The questionnaire included the same questions in 2003 and 2013. The general dental practitioners (GDPs) anonymously reported how frequent ('often', 'occasionally', and 'never') they used certain endodontic technology and adhered to central treatment principles. The statistical analyses were performed using Chi-squared test and Goodman-Kruskal's γ-coefficient as an association measure.

RESULTS

The overall response rate of the 2013 group was 46.5% (n = 531). The frequencies of GDPs reporting often use of rubber dam, apex locator and rotary NiTi instruments were significantly higher (p < .0001) than in 2003, as well as reporting the use of composite resin for coronal sealing (p < .019). Adoption was significantly influenced by the factors gender (p = .601) and time since graduation (p = .361), and the cluster analyses revealed the neglected use of rubber dam to be associated with no established postoperative recall system.

CONCLUSIONS

After 10 years, there was a higher frequency of GDPs who had adopted certain endodontic technologies. However, progress towards high-quality root canal treatment might be obstructed as the majority of GDPs avoids consistent use of rubber dam, and routinely neglects recalls for postoperative controls of their endodontic treatments.

Performance evaluation of RF coils integrated with an RF-penetrable PET insert for simultaneous PET/MRI

PURPOSE

An "RF-penetrable" PET insert that allows the MR body coil to be used for RF transmission was developed to make it easier for an existing MR center to achieve simultaneous PET/MRI. This study focuses on experiments and analyses to study PET/RF coil configurations for simultaneous PET/MR studies.

METHODS

To investigate the appropriate RF coil design, a transmit/receive (TX/RX) birdcage coil and an RX-only phased-array coil (TX from body coil), both fitting inside the PET ring were built and characterized. For MR performance evaluation, B₁ field uniformity and MR image SNR were calculated. PET photon attenuation due to each coil was studied by means of CT-based attenuation maps and reconstructed PET images.

RESULTS

When using the RX-only phased-array coil (TX from body coil), compared with the TX/RX birdcage coil, the B₁ field uniformity and the MR image (gradient echo and fast spin echo) SNR increased by 2.4±4.8%, 386.1±62.3%, and 205.0±56.5%, respectively. Although some components of the coil were distributed within the PET FOV, no significant PET photon attenuation was shown in the CT-based attenuation map and reconstructed PET images.

CONCLUSION

RF coil configurations for an RF-penetrable PET insert for simultaneous PET/MRI were studied. The RX-only phased-array coil (TX from body coil) outperformed the TX/RX birdcage coil with improved MR performance as well as negligible PET photon attenuation.

Quantitative Cross-Platform Performance Comparison between Different Detection Mechanisms in Surface Plasmon Sensors for Voltage Sensing

Surface plasmon Resonance (SPR) has recently been of interest for label-free voltage sensing. Several SPR structures have been proposed. However, making a quantitative cross-platform comparison for these structures is not straightforward due to (1) different SPR measurement mechanisms; (2) different electrolytic solution and concentration in the measurement; and (3) different levels of external applied potential. Here, we propose a quantitative approach to make a direct quantitative comparison across different SPR structures, different electrolytic solutions and different SPR measurement mechanisms. There are two structures employed as example in this theoretical study including uniform plasmonic gold sensor and bimetallic layered structure consisting of uniform silver layer (Ag) coated by uniform gold layer (Ag). The cross-platform comparison was carried by several performance parameters including sensitivity (S), full width half maximum (FWHM) and figure of merit (FoM). We also discuss how the SPR measurement mechanisms enhance the performance parameters and how the bimetallic layer can be employed to enhance the FoM by a factor of 1.34 to 25 depending on the SPR detection mechanism.

Robotic versus freehand S2 alar iliac fixation: in-depth technical considerations

Achieving fixation and fusion across the lumbosacral junction has been a challenge for spinal deformity surgeons ever since the development of instrumentation. The S2 alar-iliac (S2AI) trajectory has been introduced as a method of pelvic fixation to decrease strain on S1 screws. The S2AI screws differ in several ways from traditional iliac screws. The trajectory of these screws helps avoid the use of offset connectors due to the screws alignment with the proximal pedicle screw instrumentation. Current literature shows that S2AI screws are effective with low complication rates, but the path of these screws is intimately associated with major neural and vascular structures. Use of robotic guidance to obtain the correct trajectory has been shown to be both safe and effective in obtaining proper trajectory of S2AI screws with over 95% accuracy. Herein, we report on the technical considerations and radiographic outcomes surrounding robotic and freehand insertion of S2AI screws.

Inline Spectroscopy: From Concept to Function

The field of applied spectroscopy is strongly dominated by publications presenting proof-of-concepts, lab set-ups, and demonstrations. In contrast, the corresponding number of commercial successes of inline spectroscopy is surprisingly lower. This article discusses inline spectroscopy from an instrumentation perspective. It is the authors' firm belief that the success of inline spectroscopy lies in the understanding of how the design and implementation of the optical instrumentation affects the data quality, and how this in turn will limit or enhance the performance of the prediction model. This article emphasizes the need for a strong, multidisciplinary design team, whose design process is rooted in first principles, to bridge the technology "valley of death" and convert research in applied spectroscopy into commercially successful solutions.

Enhancement of Long-Range Surface Plasmon Excitation, Dynamic Range and Figure of Merit Using a Dielectric Resonant Cavity

In this paper, we report a theoretical framework on the effect of multiple resonances inside the dielectric cavity of insulator-insulator-metal-insulator (IIMI)-based surface plasmon sensors. It has been very well established that the structure can support both long-range surface plasmon polaritons (LRSPP) and short-range surface plasmon polaritons (SRSPP). We found that the dielectric resonant cavity under certain conditions can be employed as a resonator to enhance the LRSPP properties. These conditions are: (1) the refractive index of the resonant cavity was greater than the refractive index of the sample layer and (2) when light propagated in the resonant cavity and was evanescent in the sample layer. We showed through the analytical calculation using Fresnel equations and rigorous coupled wave theory that the proposed structure with the mentioned conditions can extend the dynamic range of LRSPP excitation and enhance at least five times more plasmon intensity on the surface of the metal compared to the surface plasmon excited by the conventional Kretschmann configuration. It can enhance the dip sensitivity and the dynamic range in refractive index sensing without losing the sharpness of the LRSPP dip. We also showed that the interferometric modes in the cavity can be insensitive to the surface plasmon modes. This allowed a self-referenced surface plasmon resonance structure, in which the interferometric mode measured changes in the sensor structure and the enhanced LRSPP measured changes in the sample channel.

Long-Term Experience With Reduction Technique in High-Grade Spondylolisthesis in the Young

Background

Surgical management of high-grade spondylolisthesis in the young is not only challenging but also controversial, from in-situ fusion to complete reduction. It is fraught with dangers such as neurological injury, pseudoarthrosis, and progressive deformity with subsequent global sagittal imbalance. We describe our experience of progressive reduction technique and restoration of lumbosacral alignment.

Methods

This study is a retrospective review of patients who underwent surgery between 1998 and 2012. The surgical technique involved positioning the hips in extension with traction, pedicle screw fixation, correction of lumbosacral kyphosis with a specific distraction maneuver, wide decompression, and gradual reduction of the deformity and maintenance of reduction with interbody fusion. All patients were serially assessed at 1, 3, and 6 months and yearly thereafter with clinical, radiological, and Oswestry Disability Index and Visual Analogue Scale outcome measures.

Results

Twenty-seven patients with high-grade spondylolisthesis at L5-S1 (3 cases grade 3, 7 grade 4, 17 grade 5) with an average age of 13.9 years were reviewed. Mean follow-up was 120 months (range 24-192). All patients presented a solid fusion at the 6-month visit; mean slip percentage was reduced from 89% to 23%, with all cases reduced to grade 2 or less. The slip angle improved from 45° to 3° postoperatively, with improvement in sacral slope from 13° to 35°. Four spondyloptosis patients had concomitant scoliosis which corrected spontaneously after the surgery and did not need further intervention. All but one patient (96.2%) had good functional outcomes and returned to their full normal activities. One patient developed a deep infection necessitating implant removal, with eventual deformity progression leading to a poor outcome. Three patients (11.1%) suffered partial drop foot that resolved in full by 12 weeks.

Conclusion

Our technique demonstrated a significant reduction of high grade spondylolisthesis, with restoration of global sagittal balance via correction of the lumbosacral kyphosis. Though surgically demanding, it is safe and reproducible.

Level of Evidence

IV.

Lubrication during root canal treatment

Lubrication is involved in all root canal treatment phases, from dental dam placement to canal obturation. Most often associated with instrumentation, lubrication is required to facilitate the mechanical action of hand/rotary files and to help emulsify and suspend the debris produced. Aqueous irrigation solutions such as sodium hypochlorite and ethylenediaminetetraacetic acid (EDTA) should be regarded as lubricants, but paste-type substances are marketed specifically for this purpose. As more patients demand the retention of challenging teeth with narrow and curved root canals, the importance of lubrication in all aspects of root canal treatment must be acknowledged.

Robotics in Orthopedics: A Brave New World

Future health-care projection projects a significant growth in population by 2020. Health care has seen an exponential growth in technology to address the growing population with the decreasing number of physicians and health-care workers. Robotics in health care has been introduced to address this growing need. Early adoption of robotics was limited because of the limited application of the technology, the cumbersome nature of the equipment, and technical complications. A continued improvement in efficacy, adaptability, and cost reduction has stimulated increased interest in robotic-assisted surgery. The evolution in orthopedic surgery has allowed for advanced surgical planning, precision robotic machining of bone, improved implant-bone contact, optimization of implant placement, and optimization of the mechanical alignment. The potential benefits of robotic surgery include improved surgical work flow, improvements in efficacy and reduction in surgical time. Robotic-assisted surgery will continue to evolve in the orthopedic field.

Single-Shot Optical Anisotropy Imaging with Quantitative Polarization Interference Microscopy

Optical anisotropy measurement is essential for material characterization and biological imaging. In order to achieve single-shot mapping of the birefringence parameters of anisotropic samples, a novel polarized light imaging concept is proposed, namely quantitative polarization interference microscopy (QPIM). QPIM can be realized through designing a compact polarization-resolved interference microscopy system that captures interferograms bearing sample's linear birefringence information. To extract the retardance and the orientation angle maps from a single-shot measurement, a mathematical model for QPIM is further developed. The QPIM system is validated by measuring a calibrated quarter-wave plate, whose fast-axis orientation angle and retardance are determined with great accuracies. The single-shot nature of QPIM further allows to measure the transient dynamics of birefringence changes in material containing anisotropic structures. This application is demonstrated by capturing transient retardance changes in a custom-designed parallel-aligned nematic liquid crystal-based device.

Prototyping Instruments for the Chemical Laboratory Using Inexpensive Electronic Modules

Open-source electronics and programming can augment chemical and biomedical research. Currently, chemists can choose from a broad range of low-cost universal electronic modules (microcontroller boards and single-board computers) and use them to assemble working prototypes of scientific tools to address specific experimental problems and to support daily research work. The learning time can be as short as a few hours, and the required budget is often as low as 50 USD. Prototyping instruments using low-cost electronic modules gives chemists enormous flexibility to design and construct customized instrumentation, which can reduce the delays caused by limited access to high-end commercial platforms.

Developing a process for assessing equivalency of wheelchair cushion pressure redistribution performance

For wheelchair users who are at risk for developing pressure ulcers, cushion prescription seeks to address tissue integrity. Because many designs of wheelchair cushions exist, a need exists to estimate their performance in supporting the body. The objective of this research was to develop an approach to assess the equivalency of cushions with respect to their pressure redistribution performance.Two instrumented compliant buttock models, differing in form, were used in the evaluation. Stress and strain parameters were used to characterize load-bearing performance. A cohort of 8 wheelchair cushions was compared to a standard reference material, HR45 foam. Each cushion was measured using both models under two loading conditions.The use of compliant buttock models that are capable of measuring both stress and strain parameters offer greater capability in measuring load-bearing performance compared to previously described methods. The proposed approach was able to evaluate cushion performance and use a logic-based approach to define whether or not a cushion was equivalent to the HR45 material. Additional study is needed to further validate the approach and to define the thresholds and criteria used to define cushion equivalency.

Development and Optimization of a Fluorescent Imaging System to Detect Amyloid-β Proteins: Phantom Study

Alzheimer disease is the most common form of dementia, affecting more than 5 million people in the United States. During the progression of Alzheimer disease, a particular protein begins to accumulate in the brain and also in extensions of the brain, ie, the retina. This protein, amyloid-β (Aβ), exhibits fluorescent properties. The purpose of this research article is to explore the implications of designing a fluorescent imaging system able to detect Aβ proteins in the retina. We designed and implemented a fluorescent imaging system with a range of applications that can be reconfigured on a fluorophore to fluorophore basis and tested its feasibility and capabilities using Cy5 and CRANAD-2 imaging probes. The results indicate a promising potential for the imaging system to be used to study the Aβ biomarker. A performance evaluation involving ex vivo and in vivo experiments is planned for future study.

SwissFEL Aramis beamline photon diagnostics

The SwissFEL Aramis beamline, covering the photon energies between 1.77 keV and 12.7 keV, features a suite of online photon diagnostics tools to help both users and FEL operators in analysing data and optimizing experimental and beamline performance. Scientists will be able to obtain information about the flux, spectrum, position, pulse length, and arrival time jitter versus the experimental laser for every photon pulse, with further information about beam shape and size available through the use of destructive screens. This manuscript is an overview of the diagnostics tools available at SwissFEL and presents their design, working principles and capabilities. It also features new developments like the first implementation of a THz-streaking based temporal diagnostics for a hard X-ray FEL, capable of measuring pulse lengths to 5 fs r.m.s. or better.

Can a Single-Use and Patient-Specific Instrumentation Be Reliably Used in Primary Total Knee Arthroplasty? A Multicenter Controlled Study

BACKGROUND

The aim of this controlled multicenter study is to evaluate the clinical and radiologic outcomes of primary total knee arthroplasty (TKA) using single-use fully disposable and patient-specific cutting guides (SU) and compare the results to those obtained with traditional patient-specific cutting guides (PSI) vs conventional instrumentation (CI).

METHODS

Seventy consecutive patients had their TKA performed using SU. They were compared to 140 historical patients requiring TKA that were randomized to have the procedure performed using PSI vs CI. The primary measure outcome was mechanical axis as measured on a standing long-leg radiograph using the hip-knee-ankle angle. Secondary outcome measures were Knee Society and Oxford knee scores, operative time, need for postoperative transfusion, and length of hospital stay.

RESULTS

The mean hip-knee-ankle value was 179.8° (standard deviation [SD] 3.1°), 179.2° (SD 2.9°), and 178.3° (SD 2.5°) in the CI, PSI and SU groups, respectively (P = .0082). Outliers were identified in 16 of 65 (24.6%), 15 of 67 (22.4%), and 14 of 70 (20.0%) knees in the CI, PSI, and SU group, respectively (P = .81). There was no significant difference in the clinical results (P = .29 and .19, respectively). Operative time, number of unit transfusion, and length of hospital stay were not significantly different between the 3 groups (P = .45, .31, and 0.98, respectively).

CONCLUSION

The use of an SU in TKA provided similar clinical and radiologic results to those obtained with traditional PSI and CI. The potential economic advantages of single-use instrumentation in primary TKA require further investigation.

Digital Holography as Computer Vision Position Sensor with an Extended Range of Working Distances

Standard computer vision methods are usually based on powerful contact-less measurement approaches but applications, especially at the micro-scale, are restricted by finite depth-of-field and fixed working distance of imaging devices. Digital holography is a lensless, indirect imaging method recording the optical wave diffracted by the object onto the image sensor. The object is reconstructed numerically by propagating the recorded wavefront backward. The object distance becomes a computation parameter that can be chosen arbitrarily and adjusted to match the object position. No refractive lens is used and usual depth-of-field and working distance limitations are replaced by less restrictive ones tied to the laser-source coherence-length and to the size and resolution of the camera sensor. This paper applies digital holography to artificial visual in-plane position sensing with an extra-large range-to-resolution ratio. The object is made of a pseudoperiodic pattern allowing a subpixel resolution as well as a supra field-of-observation displacement range. We demonstrate an in-plane resolution of 50 nm and 0.002deg. in X, Y and &theta; respectively, over a working distance range of more than 15 cm. The allowed workspace extends over 12&times;10&times;150mm3. Digital holography extends the field of application of computer vision by allowing an extra-large range of working distances inaccessible to refractive imaging systems.

Gas Cluster Ion Beams for Secondary Ion Mass Spectrometry

Gas cluster ion beams (GCIBs) provide new opportunities for bioimaging and molecular depth profiling with secondary ion mass spectrometry (SIMS). These beams, consisting of clusters containing thousands of particles, initiate desorption of target molecules with high yield and minimal fragmentation. This review emphasizes the unique opportunities for implementing these sources, especially for bioimaging applications. Theoretical aspects of the cluster ion/solid interaction are developed to maximize conditions for successful mass spectrometry. In addition, the history of how GCIBs have become practical laboratory tools is reviewed. Special emphasis is placed on the versatility of these sources, as size, kinetic energy, and chemical composition can be varied easily to maximize lateral resolution, hopefully to less than 1 micron, and to maximize ionization efficiency. Recent examples of bioimaging applications are also presented.

Temperature Resistant Fiber Bragg Gratings for On-Line and Structural Health Monitoring of the Next-Generation of Nuclear Reactors

The harsh environment associated with the next generation of nuclear reactors is a great challenge facing all new sensing technologies to be deployed for on-line monitoring purposes and for the implantation of SHM methods. Sensors able to resist sustained periods at very high temperatures continuously as is the case within sodium-cooled fast reactors require specific developments and evaluations. Among the diversity of optical fiber sensing technologies, temperature resistant fiber Bragg gratings are increasingly being considered for the instrumentation of future nuclear power plants, especially for components exposed to high temperature and high radiation levels. Research programs are supporting the developments of optical fiber sensors under mixed high temperature and radiative environments leading to significant increase in term of maturity. This paper details the development of temperature-resistant wavelength-multiplexed fiber Bragg gratings for temperature and strain measurements and their characterization for on-line monitoring into the liquid sodium used as a coolant for the next generation of fast reactors.

Permanent implantation of antibiotic cement over exposed instrumentation eradicates deep spinal infection

In this case series, we describe an infection treatment protocol involving permanent implantation of antibiotic cement that is effective in eradicating deep infection. Surgical site infection (SSI) is a devastating complication of spine surgery. Unlike the gold-standard two-stage revision in North American hip and knee arthroplasty, there exists no standardized, accepted protocol for the management of deep SSI with instrumentation. Because removal of hardware in an unstable, instrumented spine can result in serious neurologic sequelae, retention of instrumentation with elimination of bacterial colonization on implants is the goal. Using Current Procedural Terminology (CPT) codes, institutional medical records were queried to identify all posterior spinal procedures performed by the senior surgeon from 2008 through 2014. Thirty-four patients were identified as having an implant-associated SSI. Exclusion criteria included: (I) superficial SSI, and (II) those with less than 36 months of follow-up. The study population consisted of ten patients with deep implant-associated SSI who underwent our novel protocol of operative debridement and permanent coating of exposed implants with high-dose antibiotic cement. Postoperative infection presented after an average of 41.4±57.5 days (range, 6.0-207.0 days) from the index procedure. The mean follow-up was 64.4±18.1 months (range, 44.0-98.0 months). At final follow-up, none of the ten patients (0%) in our series had evidence of continued deep infection and none required removal of hardware. Ten of the ten patients (100%) were able to clear infection with a single stage debridement and coating with antibiotic cement. Only 1 of the 10 patients (10%) developed a pseudarthrosis. In conclusion, permanent implantation of antibiotic cement over exposed instrumentation is effective in preserving spinal instrumentation during infection eradication, preventing infection recurrence, and minimizing operative debridements.

Improved restoration of thoracic kyphosis using a rod construct with differentiated rigidity in the surgical treatment of adolescent idiopathic scoliosis

OBJECTIVE The objective of this study was to compare postoperative sagittal alignment among 3 rod constructs with different rigidity profiles. METHODS This was a dual-center retrospective cohort study involving 2 consecutive cohorts in which patients were surgically treated for adolescent idiopathic scoliosis. Lenke Type 5 curves were excluded. Patients were operated on with all-pedicle screw instrumentation using 3 different rod constructs. The first group was operated on using a hybrid construct (HC) consisting of a normal circular rod on the convex side and a beam-like rod (BR) on the concave side. The second group was operated on with a standard construct (SC) using bilateral BRs in the full length of the fusion. The third group was operated on with a modified construct (MC). The modified rods have a beam-like shape in the caudal portion, but in the cranial 2 or 3 fusion levels the rod transitions to a circular shape with a smaller anteroposterior diameter. Radiographs were analyzed preoperatively and at the first postoperative follow-up (range 1-8 weeks). The primary outcome was pre- to postoperative change in thoracic kyphosis (TK), and the secondary outcome was the ability to achieve postoperative TK within the normal range. RESULTS The HC, SC, and MC groups included 23, 70, and 46 patients, respectively. The 3 groups did not differ significantly in preoperative demographic or radiographic parameters. The mean ± standard deviation of the preoperative main curve was 60.7° ± 12.6°, and the mean of curve correction was 62.9% ± 10.4% with no significant difference among groups (p ≥ 0.680). The groups did not differ significantly in coronal balance or proximal or thoracolumbar curve correction (p ≥ 0.189). Mean postoperative TK was 23.1° ± 6.3°, 19.6° ± 7.6°, and 23.4° ± 6.9° in the HC, SC and MC groups, respectively (p = 0.013), and the mean change in TK was -3.5° ± 11.3°, -7.1° ± 11.6°, and 0.1° ± 10.9°, respectively (p = 0.005). The MC group had significantly higher postoperative TK and less loss of TK compared with the SC group (p ≤ 0.018). Postoperative TK ≤ 10° was found in 12 patients (17%) in the SC group, 1 patient (5%) in the HC group, and 1 patient (2%) in the MC group (p = 0.021). There were no differences in proximal alignment, thoracolumbar alignment, or sagittal vertical axis (p ≥ 0.249). Lumbar lordosis was 58.9° ± 11.2° in the HC group versus 52.0° ± 1.3° and 55.0° ± 11.0° and the SC and MC groups, respectively (p = 0.040). CONCLUSIONS In the 3 rod constructs with different rigidity profiles, significantly better restoration of kyphosis was achieved with the use of bilateral modified rods compared with bilateral standard rods. In the MC and HC groups, the rate of severe postoperative hypokyphosis was significantly lower than in the SC group. This is the first study to describe the clinical use of a rod with a reduced proximal diameter and show marked radiographic improvement in sagittal alignment.

Do Illuminated Foot Pedals Improve the Speed and Accuracy of Pedal Activation During Endoscopic Procedures?

PURPOSE

Endourologic procedures such as percutaneous nephrolithotomy (PCNL) employ the use of foot pedals in low-light operating room (OR) settings. These pedals can be especially difficult to locate or distinguish when several pedals are present during a single operation. Improper instrument activation in the OR has led to serious complications ranging from unintentional electrocautery to patient burns and even an intraoperative explosion. This study evaluates the impact of color-coded illumination on speed and efficiency of foot pedal activation.

MATERIALS AND METHODS

During a simulated PCNL procedure, the foot pedals for a C-arm, laser, and ultrasonic lithotripter (USL) were placed in random positions. Ten participants performed pedal activation in a randomized sequence. Objective outcomes included time to instrument activation, number of attempted pedal presses, number of incomplete pedal presses, and number of incorrect pedal presses. Subjective preferences for pedal illumination were also determined. Data were analyzed using Mann-Whitney U, Wilcoxon signed-rank, and Chi-square tests with p < 0.05 indicating statistical significance.

RESULTS

Illuminated foot pedals were associated with decreases in the average activation time for all instruments collectively (3.95 seconds vs 6.49 seconds; p = 0.017) and individually (C-arm: 3.07 seconds vs 4.21 seconds; p = 0.006; laser: 13.04 seconds vs 15.18 seconds; p < 0.001; USL: 3.28 seconds vs 4.91 seconds; p < 0.001) compared with nonilluminated pedals. Illuminated pedals were associated with fewer attempted pedal presses (33.5 vs 39.5; p = 0.007) and incomplete pedal presses (1.5 vs 8.5; p = 0.002). The number of incorrect pedal presses decreased with illumination, but this did not reach statistical significance (0 vs 0.5; p = 0.08). Participants reported that illumination simplified pedal activation and recommended its use (p < 0.01).

CONCLUSION

Color-coded illumination improved the speed and efficiency of foot pedal activation during simulated PCNL. Participants subjectively preferred using illuminated foot pedals for endourologic procedures and felt that they improved safety and efficiency.

Time-of-Flight Information Improved the Detectability of Subcentimeter Spheres Using a Clinical PET/CT Scanner

Recent advancements in clinical PET/CT scanners have improved the detectability of small lesions. However, the ideal reconstruction parameters for detecting small lesions have not yet been sufficiently clarified. The purpose of this study was to investigate the detectability of subcentimeter spheres using a clinical PET/CT scanner. Methods: We used a clinical PET/CT scanner to obtain the data of a National Electrical Manufacturers Association body phantom consisting of 6 small spheres (inner diameters, 4.0, 5.0, 6.2, 7.9, 10, and 37 mm) containing ¹⁸F solution. The background activity was 2.65 kBq/mL, and the sphere-to-background ratio was 8. The PET data obtained for 2 and 120 min were reconstructed using ordered-subsets expectation maximization (OSEM), OSEM + point-spread function (PSF), and OSEM + time-of-flight (TOF) with voxel sizes of 2.04 × 2.04 × 2.00 mm (2-mm voxels) and 4.07 × 4.07 × 3.99 mm (4-mm voxels). A gaussian filter was not used. The image quality was evaluated by visual assessment, as well as by physical assessment of the detectability index and recovery coefficients. Results: According to the visual assessment, the detectability of the spheres improved using TOF and a longer acquisition. Using the OSEM+TOF model, the smallest visually detected spheres were 5 mm in diameter with a 120-min acquisition and 6 mm in diameter with a 2-min acquisition. According to physical assessment, the detectability of spheres 10 mm or smaller using the OSEM+TOF image was superior to that using the OSEM image. In addition, the detectability of each hot sphere and recovery coefficient with 2-mm voxels was superior to that with 4-mm voxels. Although OSEM+PSF images showed less background noise, detectability and the recovery coefficient were not improved for spheres 8 mm or smaller. Conclusion: The TOF model with 2-mm voxels improved the detectability of subcentimeter hot spheres on a clinical PET/CT scanner.

Development of the Systems Thinking Scale for Adolescent Behavior Change

This report describes the development and psychometric testing of the Systems Thinking Scale for Adolescent Behavior Change (STS-AB). Following item development, initial assessments of understandability and stability of the STS-AB were conducted in a sample of nine adolescents enrolled in a weight management program. Exploratory factor analysis of the 16-item STS-AB and internal consistency assessments were then done with 359 adolescents enrolled in a weight management program. Test-retest reliability of the STS-AB was .71, p = .03; internal consistency reliability was .87. Factor analysis of the 16-item STS-AB indicated a one-factor solution with good factor loadings, ranging from .40 to .67. Evidence of construct validity was supported by significant correlations with established measures of variables associated with health behavior change. We provide beginning evidence of the reliability and validity of the STS-AB to measure systems thinking for health behavior change in young adolescents.