Pixel-scale miniaturization of guided mode resonance transmission filters in short wave infrared

The effects of miniaturization on theoretically predicted performance of dual-period guided mode resonance (GMR) transmission filters, which demonstrate immense potential for multispectral imaging in short wave infrared (SWIR), have been compared with experimental findings. With reducing filter size from 112 periods (90 µm) to 12 periods (10 µm), peak transmittance (Tpeak) of simulated and measured filters reduced gradually from 84% to 55% and from 76% to 65%, respectively, with a moderate change of 1 - 3 nm in full width at half maximum (FWHM). For 6 period filters (5 µm), simulations predict drastically reduced Tpeak = 14% accompanied by increase in FWHM by 12 nm. The Tpeak value is theoretically shown to increase to 46% with FWHM reduced by 7 nm upon placing metal reflectors at the optimum positions to increase the optical path length. Our findings indicate that four 5 µm × 5 µm size filters with metal reflectors designed for different resonance wavelengths can be used to form a single, 20 µm × 20 µm mosaic pixel for SWIR multispectral imaging.

1229 Standardising Consent for General Surgical Patients

Aim

Informed consent requires all material risks to be discussed, as per Montgomery vs Lanarkshire 2015. This audit was based on the latest RCS England guidelines on consenting patients. We aimed to assess our adherence and to introduce standardised procedure-specific consent stickers to ensure the highest standards of care, which were reproducible.

Method

We undertook two retrospective case note reviews of patients undergoing emergency and elective general surgery procedures from 01/01-15/06 and 01/10-30/11 in 2020. RCS Good Surgical Practice 3.5.1 “Consent” details the standards for this audit. We included patients undergoing appendicectomy, cholecystectomy, incision and drainage and hernia repair (inguinal, umbilical, and incisional). We did not audit laparotomy due to variability in procedural risks precluding a specific sticker and we excluded patients unable to give consent.

Results

Our initial audit of 82 patients highlighted the variability between practitioners in the material risk discussion. Different patients undergoing the same procedures were being consented differently with significant omissions. We designed procedure specific-consent stickers to be used when consenting to address this imbalance and made these stickers available on surgical wards. A re-audit of 50 patients showed increase from 41% to 88% in documentation of material risks. While only 34% of the audited consent forms featured the stickers, those forms that did have the stickers on had 100% material risk documentation.

Conclusions

We saw an improvement in material risk discussion by implementing procedure-specific consent stickers. This supports the growing need for standardising consent across General Surgery to reduce variability. We will next aim to design laparotomy stickers.

Utility of a Cancer Predisposition Screening Tool for Predicting Subsequent Malignant Neoplasms in Childhood Cancer Survivors

PURPOSE

Childhood cancer survivors (CCS) are at risk of developing subsequent malignant neoplasms (SMNs) resulting from exposure to prior therapies. CCS with underlying cancer predisposition syndromes are at additional genetic risk of SMN development. The McGill Interactive Pediatric OncoGenetic Guidelines (MIPOGG) tool identifies children with cancer at increased likelihood of having a cancer predisposition syndrome, guiding clinicians through a series of Yes or No questions that generate a recommendation for or against genetic evaluation. We evaluated MIPOGG's ability to predict SMN development in CCS.

METHODS

Using the provincial cancer registry (Ontario, Canada), and adopting a nested case-control approach, we identified CCS diagnosed and/or treated for a primary malignancy before age 18 years (1986-2015). CCS who developed an SMN (cases) were matched, by primary cancer and year of diagnosis, with CCS who did not develop an SMN (controls) over the same period (1:5 ratio). Potential predictors for SMN development (chemotherapy, radiation, and MIPOGG output) were applied retrospectively using clinical data pertaining to the first malignancy. Conditional logistic regression models estimated hazard ratios and 95% CIs associated with each covariate, alone and in combination, for SMN development.

RESULTS

Of 13,367 children with a primary cancer, 317 (2.4%) developed an SMN and were matched to 1,569 controls. A MIPOGG output recommending evaluation was significantly associated with SMN development (hazard ratio 1.53; 95% CI, 1.06 to 2.19) in a multivariable model that included primary cancer therapy exposures. MIPOGG was predictive of SMN development, showing value in nonhematologic malignancies and in CCS not exposed to radiation.

CONCLUSION

MIPOGG has additional value for SMN prediction beyond treatment exposures and may be beneficial in decision making for enhanced individualized SMN surveillance strategies for CCS.

Plasmonic colors in titanium nitride for robust and covert security features

A mechanically robust metasurface exhibiting plasmonic colors across the visible and the near-IR spectrum is designed, fabricated, and characterized. Thin TiN layers (41 nm in thickness) prepared by plasma-enhanced atomic layer deposition (ALD) are patterned with sub-wavelength apertures (75 nm to 150 nm radii), arranged with hexagonal periodicity. These patterned films exhibit extraordinary transmission in the visible and the near-IR spectrum (550 nm to 1040 nm), which is accessible by conventional Si CCD detectors. The TiN structures are shown to withstand high levels of mechanical stresses, tested by rubbing the films against a lint-free cloth under 14.5 kPa of load for 30 minutes, while structures patterned on gold, a widely used plasmonic material, do not. The subwavelength nature of the plasmonic resonances, coupled with robustness and durability of TiN, makes these structures an attractive choice for use in nanoscale security features for heavily handled objects. Furthermore, ALD of these films enables scalability, which in conjunction with the cost-effectiveness of the process and material (TiN) makes the entire process industry friendly.

Hematology and serum chemistry reference values of stray dogs in Bangladesh

Hematology and serum chemistry values were obtained from 28 male and 22 female stray dogs in Chittagong Metropolitan area, Bangladesh. The goal of the study was to establish reference value for hematology and serum chemistry for these semi wild animals in relation to age, sex, reproductive stage and body condition. No significant differences were found for mean values of hemoglobin, packed cell volume, mean corpuscular hemoglobin concentration, white blood cell, differential leukocyte count, total protein, albumin, glucose, cholesterol, phosphorus and potassium among or between sexes, ages, reproductive states or body conditions. Significant differences were noted for erythrocyte sedimentation rate (p<0.02) between sexes. Among different age groups significant differences were found for total red blood cell count (p<0.001). Different body conditions have significant differences in red blood cell count, mean corpuscular volume and mean corpuscular hemoglobin (p<0.001). Pregnant and non-pregnant females differed significantly in their red blood cell count, mean corpuscular volume and mean corpuscular hemoglobin (p<0.001).

Survey of knowledge of simple pulmonary function tests (PFTs) amongst trainee doctors in England

The understanding of and interpretation skills for simple pulmonary function tests (PFTs) are increasingly required in the everyday practice of medicine. This knowledge was evaluated amongst the trainee hospital doctors in the north-east of England. Three-hundred questionnaire sets were sent in the post to the relevant junior doctors working in the north-east of England and sixty-nine completed sets were returned: a raw response rate of 23% and a corrected response rate of 27%. There were deficits in knowledge and confidence in most tests except for those which were most commonly used, and this was noted across the different grades of junior doctors. The respondents were aware of the deficiency and most would like further teaching and input during their hospital career. An appropriate plan for improvement should be formulated and implemented.

The Darlington and Northallerton Prospective Asthma Study: best function predicts mortality during the first 10 years

The Darlington/Northallerton prospective study of asthmatics referred to secondary care started in 1983, with review and new entry at 5-yr intervals. The principal outcome measures are: mortality (presented here), best function and therapeutic step. All adult asthmatics with > or = 15% peak flow (PEF) reversibility to > or = 200 l min-1 were included. Socio-demographic variables, PEF and spirometry were recorded prospectively. Best vital capacity (FVC) and PEF were assessed according to protocol. The mortality of the original cohort after 10 yr was expressed as standardized mortality ratio (SMR) against the local population, with history and pulmonary function at entry as explanatory variables. Ninety-five per cent follow-up was achieved in 628 subjects, with 173 deaths (29.1% of those traced). The excess death rate was nearly 50% (SMR 1.47, 95% CI 1.26-1.71), with 56% of deaths due to respiratory disease (expected 10%). After allowance for age and sex, there was a consistent inverse relationship between mortality and entry best FVC, increased risk of death 1.51 (95% CI 1.33-1.72) per 10% deficit of best FVC predicted. The risk of respiratory death was eight times greater, and of non-respiratory death three times greater, in the lowest compared with the highest quartile of best FVC. There were no interactions with smoking, but possible enhancement of the effect in the socially deprived. Best FVC was a particularly powerful predictor of mortality in subjects < 65 years at entry, in whom 64% of the excess deaths occurred. Most of the excess in respiratory deaths was not due to acute severe asthma but to the development of chronic obstructive pulmonary disease (COPD), as defined functionally, irrespective of smoking habit which made no further contribution to mortality.

Symptoms and pulmonary function in asthma

The relationship between symptoms and pulmonary function in asthma is important if the latter is to be held relevant to management guidelines and their audit. Associations between reported symptoms, pulmonary function and therapy were studied in 824 asthmatics (mean FEV1 75.4% predicted; best FEV1 84.6% predicted; and actual/best peak flow (PEF) 87.5%). Bronchodilator usage (reflecting symptomatic wheeze) was evenly distributed up to eight times daily; 22.5% of subjects had nocturnal disturbance and 46.3% persistent daytime symptoms. The univariate relationships between symptoms and function were generally closer with best rather than actual/best. They were further explored using quintiles of function. Symptoms were consistently less as best function increased, but were highly significantly greater in the fifth than in the third and fourth quintiles of actual/best FEV1. There was a trend to a similar U-shaped relationship of actual/best PEF with nocturnal disturbance and daytime symptoms. Best function is a good determinant of expected symptom load in an asthmatic population. Below 85% actual/best function reflects the prevalence of symptoms. In asymptomatic patients a level of at least 85-90% is a useful check of physiological control but will not exclude some symptomatic patients, irrespective of best function.