Comparing negative health indicators in male and female veterans with the Canadian general population.

INTRODUCTION: Sex-based information on differences between Canadian veterans and the general population is important to understand veterans' unique health needs and identify areas requiring further research. This study compared various health indicators in male and female veterans with their Canadian counterparts. METHODS: Health indicators for recent-era Regular Force veterans (released between 1998 and 2015) were obtained from the 2016 Life After Service Survey and compared with the general population in the 2015-16 Canadian Community Health Survey using a cross-sectional approach. Age-adjusted rates and 95% CIs were calculated for males and females separately. RESULTS: Compared with Canadians, veterans (both sexes) reported higher prevalence of fair or poor health and mental health, needing help with one or more activity of daily living, lifetime suicidal ideation and being diagnosed with mood and anxiety disorders, post-traumatic stress disorder, migraines, back problems, chronic pain, arthritis, ever having cancer, hearing problems, chronic pain and gastrointestinal problems. A higher prevalence of cardiovascular disease (all types) and high blood pressure was observed in male veterans compared with their Canadian counterparts. Within veterans only, males reported a higher prevalence of diagnosed hearing problems and cardiovascular disease compared with females; conversely females reported a higher prevalence of diagnosed migraines, mood, anxiety and gastrointestinal disorders, and needing help with activities of daily living. These sex differences are similar to the Canadian general population. Some similarities in reporting prevalence between male and female veterans (eg, fair or poor mental health, lifetime suicidal ideation, arthritis, asthma, lifetime cancer incidence, chronic pain and diabetes) were not observed in other Canadians. CONCLUSION: Male and female veterans differed from comparable Canadians, and from each other, in various areas of health. Further research is needed to explore these findings, and veteran-based policies and services should consider sex differences.

Robotic retroperitoneal lymph node dissection for primary and post-chemotherapy testis cancer.

The role of retroperitoneal lymph node dissection (RPLND) in testicular cancer is well established in both the primary and post-chemotherapy setting. The aim of this study was to report our 2 years oncological outcomes of robotic RPLND. A retrospective review was performed of all patients undergoing robotic RPLND by a single surgeon at Princess Margaret Cancer Centre. Demographic, perioperative, and oncologic data were analyzed using descriptive statistics. Between September 2014 and June 2020, 141 patients underwent an RPLND [33 (23.4%) were primary, 108 (76.6%) were post-chemotherapy]. 27 (19.1%) patients underwent a robotic bilateral template nerve-sparing RPLND. RPLND indication was primary (i.e. pre-chemotherapy) in 18 (66.7%), and post-chemotherapy in 9 (33.3%) patients. Stage at RPLND was 2A (n = 15, 55.6%), 2B (n = 9, 33.3%), 2C (n = 1, 3.7%) and 3 (n = 2, 7.4%). Median OR time (incision to closure) was 525 min and blood loss was 200 ml. Nerve sparing was performed in all but one case. Six (22.2%) adjuvant procedures were performed including two (7.4%) vascular repairs. Median length of stay was 2 days. Viable tumor was detected in 17 (63%) and teratoma in 9 (33.3%). Median follow-up was 31.3 months. No adjuvant chemotherapy was given. Three patients (11.1%) relapsed: 2 out-of-field and 1 with both in-field and out-of-field disease. Robotic RPLND can be performed safely. Long-term follow-up of series such as ours, enriched with patients with viable disease and/or teratoma, and not treated with adjuvant chemotherapy is required to ensure oncological outcomes are comparable to the open approach.

Partial orchiectomy: The Princess Margaret cancer centre experience.

INTRODUCTION: Radical orchiectomy (RO) is the standard treatment for a testis cancer. Organ sparing surgery can be considered in the setting of a solitary functioning testis or bilateral tumors. It has also been suggested as an alternative to RO for small lesions. In this study we report our partial orchiectomy (PO) experience. METHODS: We performed a retrospective review using our prospectively maintained database analyzing PO. RESULTS: Between 1983 and 2018, 77 patients underwent PO. Mean age was 31.3 years (range 17-56). A lesion was palpable in 70 (90.9%) and median lesion size 14.1 mm (range 3-35 mm). Reasons for PO included ``small lesion" in 39 (50.6%); solitary functioning testis in 30 (39%); bilateral lesions in 6 (7.8%); or assumed benign lesion in 1 (1.3%). Median follow-up was 43.5 months (range 1-258). Lesion histology was benign in 25 (32.5%). A positive surgical margin was noted in 6 (7.8%) with none developing local or distant recurrence. Sixteen (20.8%) patients underwent salvage ipsilateral RO at a median of 3 months (range 0-46). Reasons for salvage RO included a radiologically detected lesion in 7, palpable lesion in 4, positive surgical margin in 3 and adverse pathology in 2 patients. Malignant histology was present in 12 (75%) of the salvage RO specimens. There were no reported Clavien-Dindo Grade 3 to 5 complications. CONCLUSION: Organ sparing surgery is a safe and feasible approach to small testis lesions. For the third with benign disease, and even those with malignant histology, a RO can be avoided in carefully selected patients.

Closed-loop cortical control of virtual reach and posture using Cartesian and joint velocity commands.

OBJECTIVE: Brain-computer interfaces (BCIs) are a promising technology for the restoration of function to people with paralysis, especially for controlling coordinated reaching. Typical BCI studies decode Cartesian endpoint velocities as commands, but human arm movements might be better controlled in a joint-based coordinate frame, which may match underlying movement encoding in the motor cortex. A better understanding of BCI controlled reaching by people with paralysis may lead to performance improvements in brain-controlled assistive devices. APPROACH: Two intracortical BCI participants in the BrainGate2 pilot clinical trial performed a visual 3D endpoint virtual reality reaching task using two decoders: Cartesian and joint velocity. Task performance metrics (i.e. success rate and path efficiency) and single feature and population tuning were compared across the two decoder conditions. The participants also demonstrated the first BCI control of a fourth dimension of reaching, the arm's swivel angle, in a 4D posture matching task. MAIN RESULTS: Both users achieved significantly higher success rates using Cartesian velocity control, and joint controlled trajectories were more variable and significantly more curved. Neural tuning analyses showed that most single feature activity was best described by a Cartesian kinematic encoding model, and population analyses revealed only slight differences in aggregate activity between the decoder conditions. Simulations of a BCI user reproduced trajectory features seen during closed-loop joint control when assuming only Cartesian-tuned features passed through a joint decoder. With minimal training, both participants controlled the virtual arm's swivel angle to complete a 4D posture matching task, and achieved significantly higher success using a Cartesian + swivel velocity decoder compared to a joint velocity decoder. SIGNIFICANCE: These results suggest that Cartesian velocity command interfaces may provide better BCI control of arm movements than other kinematic variables, even in 4D posture tasks with swivel angle targets.

Signal processing methods for reducing artifacts in microelectrode brain recordings caused by functional electrical stimulation.

OBJECTIVE: Functional electrical stimulation (FES) is a promising technology for restoring movement to paralyzed limbs. Intracortical brain-computer interfaces (iBCIs) have enabled intuitive control over virtual and robotic movements, and more recently over upper extremity FES neuroprostheses. However, electrical stimulation of muscles creates artifacts in intracortical microelectrode recordings that could degrade iBCI performance. Here, we investigate methods for reducing the cortically recorded artifacts that result from peripheral electrical stimulation. APPROACH: One participant in the BrainGate2 pilot clinical trial had two intracortical microelectrode arrays placed in the motor cortex, and thirty-six stimulating intramuscular electrodes placed in the muscles of the contralateral limb. We characterized intracortically recorded electrical artifacts during both intramuscular and surface stimulation. We compared the performance of three artifact reduction methods: blanking, common average reference (CAR) and linear regression reference (LRR), which creates channel-specific reference signals, composed of weighted sums of other channels. MAIN RESULTS: Electrical artifacts resulting from surface stimulation were 175 × larger than baseline neural recordings (which were 110 µV peak-to-peak), while intramuscular stimulation artifacts were only 4 × larger. The artifact waveforms were highly consistent across electrodes within each array. Application of LRR reduced artifact magnitudes to less than 10 µV and largely preserved the original neural feature values used for decoding. Unmitigated stimulation artifacts decreased iBCI decoding performance, but performance was almost completely recovered using LRR, which outperformed CAR and blanking and extracted useful neural information during stimulation artifact periods. SIGNIFICANCE: The LRR method was effective at reducing electrical artifacts resulting from both intramuscular and surface FES, and almost completely restored iBCI decoding performance (>90% recovery for surface stimulation and full recovery for intramuscular stimulation). The results demonstrate that FES-induced artifacts can be easily mitigated in FES + iBCI systems by using LRR for artifact reduction, and suggest that the LRR method may also be useful in other noise reduction applications.

Clinical Characteristics and Outcomes of Late Relapse in Stage I Testicular Seminoma.

AIMS: To identify the characteristics and outcomes associated with late relapse in stage I seminoma. MATERIALS AND METHODS: A retrospective review was carried out of all patients with stage I seminoma managed at our institution between 1981 and 2011. Data were obtained from a prospectively maintained database. Late relapse was defined as tumour recurrence > 2 years after orchiectomy. RESULTS: Overall, 1060 stage I seminoma patients were managed with active surveillance (n=766) or adjuvant radiotherapy (n=294). At a median follow-up of 10.6 years (range 1.2-30), 142 patients relapsed at a median (range) of 14 (3-129) months; 128 on active surveillance and 14 after adjuvant radiotherapy. The late relapse rate for the active surveillance and adjuvant radiotherapy groups was 4% and 1%, respectively. There was no specific clinicopathological factor associated with late relapse. Isolated para-aortic node(s) was the most common relapse site in active surveillance patients either in late (88%) or early relapse (82%). Among the active surveillance group, no patients with late relapse subsequently developed a second relapse after either salvage radiotherapy (n=25) or chemotherapy (n=6), whereas in early relapse patients a second relapse was reported in seven (10%) of 72 patients treated with salvage radiotherapy and one (4%) of 23 patients who received chemotherapy; all second relapses were subsequently salvaged with chemotherapy. No patient in the adjuvant radiotherapy group developed a second relapse after salvage chemotherapy (n=10) or inguinal radiotherapy/surgery (n=4). Of seven deaths, only one was related to seminoma. Among active surveillance patients, the 10 year overall survival for late and early relapse groups were 100% and 96% (P = 0.2), whereas the 10 year cancer-specific survival rates were 100% and 99% (P = 0.3), respectively. CONCLUSIONS: In stage I seminoma, the extent and pattern of late relapse is similar to that for early relapse. For active surveillance patients, selective use of salvage radiotherapy/chemotherapy for relapse results in excellent outcomes regardless of the timing of relapse, whereas salvage radiotherapy for late relapse seems to be associated with a minimal risk of second relapse.

Developmental guidelines for good chairside teaching ­ a consensus report from two conferences.

Developmental Guidelines for Chairside Teaching are a direct outcome of 10 years of research, originally prompted by feedback from undergraduate dental students who not only thought that the teaching they received was uneven and variable in quality, but also felt strongly that they learned more with educationally trained teachers than those with little or no teacher training. Workshops embracing the views of teaching colleagues from many other Dental Schools produced a consensus view that developmental guidelines for teachers would provide a valuable resource. A conference to consider all aspects on chairside teaching and learning was convened with delegates invited from all UK Dental Schools. This was subsequently followed by a second conference to develop specific guidelines for chairside teaching and learning. The Nominal Group Technique was used in the first chairside teaching conference, and Structured Small Expert Groups were used in the second. The overall consensus from these workshops and conferences were as follows: (i) developmental guidelines for chairside teaching can act as a useful resource for teachers to improve and maintain their standard of chairside teaching, (ii) developmental guidelines can be divided into themes of organisational issues and learner and teacher qualities, and (iii) Guidelines should be 'developmental' because they encourage chairside teachers to focus on the next immediate goal to maintain and improve quality and standards. These developmental guidelines could provide a universal toolkit for improved chairside teaching which would result in a better student learning experience. Set out in this way these guidelines have currency across academic and practical skills levels, different educational systems, philosophies and country boundaries.

A pilot 'window of opportunity' neoadjuvant study of metformin in localised prostate cancer.

BACKGROUND: Metformin is an inhibitor of complex 1 in the respiratory chain, and is widely used to reduce insulin resistance. It has also been described to have pleotropic effects including via AMPK on inhibiting the mTOR kinase. Pre-clinical and epidemiological studies suggest an ability to modulate disease evolution in prostate cancer. In this study, we aimed to (i) demonstrate safety and tolerability of neoadjuvant metformin administration and (ii) document changes in proliferative (Ki67) and AMPK-related signalling indices between matching biopsies and prostatectomies METHODS: Men were treated in a single-arm 'window of opportunity' study between their decision to undergo radical prostatectomy and the operation itself. Forty patients were planned but only 24 patients were enrolled owing to slow accrual. Twenty-one patients were evaluable for pathological outcomes and 22 for serum metabolic indices. Metformin was given at doses to 500 mg t.i.d. Ki67 index was calculated using the Aperio-positive pixel count algorithm, whereas immunohistochemical measurements were by consensus H-Score. Comparative statistics were analysed by students t-tests and/or Wilcoxon matched pairs signed rank test. RESULTS: Baseline characteristics included median PSA 6 ng ml(-1) (3.22-36.11 ng ml(-1)). Median duration of drug treatment was 41 days (18-81). Treatment was well tolerated with only three patients developing G3/4 toxicities. In a per patient and per tumour analyses, metformin reduced the Ki67 index by relative amounts of 29.5 and 28.6 % (P=0.0064 and P=0.0042) respectively. There was also a significant decrease in P-4EBP1 staining (P<0.001) but no change in P-AMPK or P-ACC. There were no correlations between any metabolic, morphometric or cancer-related serum indices. There was a trend towards PSA reduction (P=0.08). The study is limited by small patient numbers and tumour heterogeneity. CONCLUSIONS: Neoadjuvant metformin is well tolerated prior to radical prostatectomy. Data to date indicate promising effects on metabolic and tissue proliferation and signalling parameters.

A comparison of two forms of teaching instruction: video vs. live lecture for education in clinical periodontology.

INTRODUCTION: This crossover controlled study aimed to compare the knowledge and skill attained by third-year dental students in three clinical exercises in the discipline of periodontology through video and live lecture instruction. METHODS: Students (n = 35) segregated into two group either viewed a video or attended a live lecture repeated over three clinical teaching sessions. Pre-test and post-test written assessments were completed and comparisons between video and live lecture done (analysis of variance, P < 0.05). Students were assessed on clinic by a simple checklist. A questionnaire was administered after all three sessions to determine preferences and opinions on video and live lecture. RESULTS: For the combined three sessions, both video (n = 48) and live lecture (n = 47) groups attained similar mean pre-test scores. The mean post-test score was statistically significantly greater (P = 0.049) for the live lecture (74.9%, SD 14.9) compared to the video group (68.6%, SD 16.3). All students attained clinical proficiency via the simple checklist. In adding to their clinical skill, more students favoured video (97%) vs. live lecture (78.8%). Most students (97%) favoured a future combination of video and lecture. DISCUSSION: While students were deemed clinically competent via a simple checklist, the live lecture group performed better than the video group via the in-depth post-test assessment. Students had a preference for video and would like it integrated in the lecture rather than act as a substitute for the lecture. CONCLUSION: The use of video alone in clinical periodontology training may have limitations unless supplemented by appropriate learning activities.

SU-E-T-189: Arc Splitting for VMAT Patient QA.

PURPOSE: To determine the need for arc splitting for VMAT prostate patient quality assurance. METHODS: Prior to Eclipse version 10.0, a verification plan for VMAT treatment could only be created which mirrored the clinical plan; if the plan called for a full arc, then the verification plan also contained a full arc. In this case, for a center that uses the Sun Nuclear MapCheck device with its Isocentric Mounting Fixture, the full fluence of an arc is delivered en face to the device. The question arose as to whether partial arcs, if they could be created, would fail a center's criteria, while the full arc passed them, in effect, whether there are cancellations occurring and not being observed. With Eclipse version 10.0, it is now possible to split a clinical arc into many subdivisions for verification, the software recommends no more than 40 partial arcs, for computing speed limitations. Twelve VMAT plans for prostate patients were investigated, in order to search for the aforementioned cancellations. Two full arcs were used clinically in all cases. Verification plans were created consisting of (1) the two full arcs; (2) 8 partial arcs of 90 degrees each; and (3) 16 partial arcs of 45 degrees each. These were all analyzed against our criteria of 3%/3mm with a threshold of 10%, and 95% of points passing. RESULTS: Of 288 partial arcs and 49,670 points analyzed, there were a total of 100 points (0.2%) that failed the 3%/3mm criteria. No arcs, however, failed the 95% passing criteria. Moreover, there was no evidence of cancellation; if a point failed low, there was no corresponding high failure in another partial arc. CONCLUSIONS: In this study, splitting a full arc into partial arcs revealed no unseen failures.

Modelling and fabrication of GaAs photonic-crystal cavities for cavity quantum electrodynamics.

In this paper, we present recent progress in the growth, modelling, fabrication and characterization of gallium arsenide (GaAs) two-dimensional (2D) photonic-crystal slab cavities with embedded indium arsenide (InAs) quantum dots (QDs) that are designed for cavity quantum electrodynamics (cQED) experiments. Photonic-crystal modelling and device fabrication are discussed, followed by a detailed discussion of different failure modes that lead to photon loss. It is found that, along with errors introduced during fabrication, other significant factors such as the presence of a bottom substrate and cavity axis orientation with respect to the crystal axis, can influence the cavity quality factor (Q). A useful diagnostic tool in the form of contour finite-difference time domain (FDTD) is employed to analyse device performance.

A mathematical model of exposure of non-target Lepidoptera to Bt-maize pollen expressing Cry1Ab within Europe.

Genetically modified (GM) maize MON810 expresses a Cry1Ab insecticidal protein, derived from Bacillus thuringiensis (Bt), toxic to lepidopteran target pests such as Ostrinia nubilalis. An environmental risk to non-target Lepidoptera from this GM crop is exposure to harmful amounts of Bt-containing pollen deposited on host plants in or near MON810 fields. An 11-parameter mathematical model analysed exposure of larvae of three non-target species: the butterflies Inachis io (L.), Vanessa atalanta (L.) and moth Plutella xylostella (L.), in 11 representative maize cultivation regions in four European countries. A mortality-dose relationship was integrated with a dose-distance relationship to estimate mortality both within the maize MON810 crop and within the field margin at varying distances from the crop edge. Mortality estimates were adjusted to allow for physical effects; the lack of temporal coincidence between the susceptible larval stage concerned and the period over which maize MON810 pollen is shed; and seven further parameters concerned with maize agronomy and host-plant ecology. Sublethal effects were estimated and allowance made for aggregated pollen deposition. Estimated environmental impact was low: in all regions, the calculated mortality rate for worst-case scenarios was less than one individual in every 1572 for the butterflies and one in 392 for the moth.

One dimensional resonant Fibonacci quasicrystals: noncanonical linear and canonical nonlinear effects.

A detailed experimental and theoretical study of the linear and nonlinear optical properties of different Fibonacci-spaced multiple-quantum-well structures is presented. Systematic numerical studies are performed for different average spacing and geometrical arrangement of the quantum wells. Measurements of the linear and nonlinear (carrier density dependent) reflectivity are shown to be in good agreement with the computational results. As the pump pulse energy increases, the excitation-induced dephasing broadens the exciton resonances resulting in a disappearance of sharp features and reduction in peak reflectivity.

Educational innovations for dentistry.

Over the past four decades, teaching and learning in higher education has been informed by a variety of educational theories. The various initiatives that have been introduced as a consequence have all sought to improve students' educational experiences. However, such moves have not always been successful, as a series of three articles that the authors produced on dental chairside teaching have demonstrated. The first of these investigated the stakeholders' perceptions of this teaching at one dental school. The second evaluated chairside teaching on a UK wide scale, while the third provided educational tools to encourage collaboration among clinical educators to share good chairside teaching practices. What this paper seeks to do is to locate each of these themes within the wider context of a theoretical frame highlighting the need for dental education to be underpinned by such constructs. The aim of this paper is to help ensure that an informed learning experience is achieved for all students engaged in clinical dental education.

Attempts to grow optically coupled Fibonacci-spaced InGaAs/GaAs quantum wells result in surface gratings.

An instability in the growth of nonperiodic InGaAs/GaAs multiple quantum well samples, ordinarily of high-quality when grown with equal periods of order of half the wavelength of light in the material, leads to a dramatic microscopic, self-organized surface grating. This effect was discovered while growing quantum wells with two unequal barrier lengths arranged in a Fibonacci sequence to form an optical quasicrystal. A laser beam incident normal to the surface of the sample is diffracted into a propeller-shaped pattern. The sample surface has a distinctly cloudy appearance when viewed along one crystal axis but is mirror-like when the sample is rotated 90 degrees. The instability results in a five-fold increase in the absorption linewidth of the heavy-hole exciton transition. Atomic force microscopy, transmission electron microscopy, and scanning electron microscopy were used to study the samples.

Tools to share good chairside teaching practice: a clinical scenario and appreciative questionnaire.

This article provides a scenario for analysis of good chairside teaching practice to serve as a starting point for continued discussion in this complex field. Documented issues of good chairside teaching practice are cross-referenced to a clinical scenario with explanations in the form of a commentary. This provided the context for generating a set of questions that are provided as tools to support good chairside practice. These tools are designed to be used with 'Appreciative Inquiry', which claims that there is much to be gained by discovering where excellence is possible and elaborating upon this. Although this process can be carried out in single units or departments, it is proposed that collaboration between institutions would allow sharing of valuable innovations and greater understanding of educational training, production of good practice guidance and professional development of staff. This article is the third in a series of three and provides a scaffold for a scenario and questions to encourage collaboration in evolving and sharing good chairside teaching practice. The first article investigated the perceptions of stakeholders in chairside teaching at a single dental school and the second evaluated chairside teaching on a UK wide scale. A further accompanying article reviews some of the educational methodology and innovations in teaching and learning that may be applied to dentistry.

Chairside teaching and the perceptions of dental teachers in the UK.

This study outlines how dental tutors at the chairside view their teaching and describes what are considered important current issues, requirements and recommendations for good chairside teaching practice. A qualitative analysis was undertaken of stakeholder perceptions of chairside teaching from both a single dental school study and a UK wide evaluation workshop. The evaluation of good chairside teaching showed that training requirements might be quite different for different stakeholders in chairside teaching. Further, this evaluation process may serve as a process model for institutional change for improvements in chairside teaching. This article is the second of a series of three and evaluates chairside teaching on a UK wide scale. The first, investigated the perceptions of stakeholders of chairside teaching at a single dental school. The third provides educational tools to encourage collaboration and sharing good chairside teaching practice. A further accompanying article reviews some of the educational methodology and innovations in teaching and learning that may be applied to dentistry.

Stakeholder perceptions of chairside teaching and learning in one UK dental school.

As a hands-on clinical educational programme, undergraduate dentistry is an anomaly in higher education. This study aimed to evaluate the perceptions of chairside teaching of dental team stakeholders, including dental nurses, dental students and dental tutors at a single UK dental school. From this sample the penetration of current learning and teaching innovations within higher education into the specialist field of clinical dentistry could be evaluated. This article is the first of a series of four which investigates the perceptions of stakeholders of chairside teaching at a single dental school. The second evaluates chairside teaching on a UK wide scale. The third provides educational tools to encourage collaboration and sharing good chairside teaching practice. A further accompanying article reviews some of the educational methodology and innovations in teaching and learning that may be applied to dentistry.

Excitonic polaritons in Fibonacci quasicrystals.

The fabrication and characterization of light-emitting one-dimensional photonic quasicrystals based on excitonic resonances is reported. The structures consist of high-quality GaAs/AlGaAs quantum wells grown by molecular-beam epitaxy with wavelength-scale spacings satisfying a Fibonacci sequence. The polaritonic (resonant light-matter coupling) effects and light emission originate from the quantum well excitonic resonances. Measured reflectivity spectra as a function of detuning between emission and Bragg wavelength are in good agreement with excitonic polariton theory. Photoluminescence experiments show that active photonic quasicrystals, unlike photonic crystals, can be good light emitters: While their long-range order results in a stopband similar to that of photonic crystals, the lack of periodicity results in strong emission.