Adsorption isotherms for water on homoionic (Ca2+, Li+, Na+, and K+) exchanged forms of Crook County, Wyoming, montmorillonite (CMS Source Clay SWy-1) were measured between 25° and 70°C using a vacuum microbalance having automated control of water vapor pressure. From these adsorption data, integral enthalpies and entropies of adsorption were calculated. Both quantities were negative, but decreased in magnitude with increasing amounts of adsorbed water. For all four cationic forms of the clay, the amount of initial water adsorption at 25°C and at low relative humidities was sensitive to the sample temperature during prior evacuation of water, less water being adsorbed by samples evacuated at 100°C compared with samples evacuated at 25°. For Ca- and Na-montmorillonite, these changes were reversible after several subsequent desorption/adsorption cycles, but recovery was not observed for the Li-SWy-1 clay, probably because of migration of Li+ into the aluminosilicate structure.

The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.

OBJECTIVES/SPECIFIC AIMS: The objective of this study is to use machine Learning techniques to generate maps of epithelium and lumen density in MRI space. METHODS/STUDY POPULATION: Methods: We prospectively recruited 39 patients undergoing prostatectomy for this institutional review board (IRB) approved study. Patients underwent MP-MRI before prostatectomy on a 3T field strength MRI scanner (General Electric, Waukesha, WI, USA) using an endorectal coil. MP-MRI included field-of-view optimized and constrained undistorted single shot (FOCUS) diffusion weighted imaging with 10 b-values (b=0, 10, 25, 50, 80, 100, 200, 500, 1000, and 2000), dynamic contrast enhanced imaging, and T2-weighted imaging. T2 weighted images were intensity normalized and apparent diffusion coefficient maps were calculated. The dynamic contrast enhanced data was used to calculate the percent change in signal intensity before and after contrast injection. All images were aligned to the T2 weighted image. Robotic prostatectomy was performed 2 weeks after image acquisition. Prostate samples were sliced using a 3D printed slicing jig matching the slice profile of the T2 weighted image. Whole mount samples at 10 μm thickness were taken, hematoxylin and eosin stained, digitized, and annotated by a board certified pathologist. A total of 210 slides were included in this study. Lumen and epithelium were automatically segmented using a custom algorithm written in MATLAB. The algorithm was validated by comparing manual to automatic segmentation on 18 samples. Slides were aligned with the T2 weighted image using a nonlinear control point warping technique. Lumen and epithelium density and the expert annotation were subsequently transformed into MRI space. Co-registration was validated by applying a known warp to tumor masks noted by the pathologist and control point warping the whole mount slide to match the transform. Overlap was measured using a DICE coefficient. A learning curve was generated to determine the optimal number of patients to train the algorithm on. A PLS algorithm was trained on 150 random permutations of patients incrementing from 1 to 29 patients. Slides were stratified such that all slides from a single patient were in the same cohort. Three cohorts were generated, with tumor burden balanced across all cohort. A PLS algorithm was trained on 2 independent training sets (cohorts 1 and 2) and applied to cohort 3. The input vector consisted of MRI values and the target variable was lumen and epithelium density. The algorithm was trained lesion-wise. Trained PiCT models were applied to the test cohort voxel-wise to generate 2 new image contrasts. Mean lesion values were compared between high grade, low grade, and healthy tissue using an ANOVA. An ROC analysis was performed lesion-wise on the test set. RESULTS/ANTICIPATED RESULTS: Results: The segmentation accuracy validation revealed R=0.99 and R=0.72 (p<0.001) for lumen and epithelium, respectively. The co-registration accuracy revealed a 94.5% overlap. The learning curve stabilized at 10 patients with a root mean square error of 0.14, thus the size of the 2 independent training cohorts was set to 10, leaving 19 for the test cohort. DISCUSSION/SIGNIFICANCE OF IMPACT: We present a technique for combining radiology and pathology with machine learning for generating predictive cytological topography (PiCT) maps of cellularity and lumen density prostate. The voxel-wise approach to mapping cellular features generates 2 new interpretable image contrasts, which can potentially increase confidence in diagnosis or guide biopsy and radiation treatment.

It is shown from studies of synthetic kaolinites doped with Fe3+ that the ESR spectrum of kaolinite at g = 4 consists of two components attributed to Fe3+ ions occupying two distinct substitutional sites (Centres I and II). The relative intensity of the two components can be correlated with the X-ray crystallinity of the samples. The ESR spectrum is influenced by artificial changes in crystallinity produced by subjecting samples to high stresses or by intercalation. It is concluded that Centre II is due to Fe3+ replacing Al3+ in the octahedral layer in a region of high crystallinity. Centre I is assigned to Fe3+ occupying Al3+ sites distorted by changes in the hydroxyl orientations associated with layer stacking disorder or disruption of interlayer bonding.

A stable defect centre in kaolinite which produces an ESR spectrum at g = 2·0 is attributed to either a hole centre located on an Si—O bond adjacent to an Mg2+ octahedral impurity or to an O2− ion trapped within the lattice.

A review is given of the application of ESR spectroscopy to the study of hydrated transition metal ions and nitroxide spin probes in the interlamellar region of smectites and vermiculites. These investigations have not only provided information regarding the structure and mobility of the intracrystalline water-cation layers but have also demonstrated the reactivity and catalytic properties of certain transition metal exchange forms of smectites. Several novel coordination complexes and redox reactions between the exchange ions and a variety of simple organic molecules have been characterized.

Synthetic kaolinites of varying crystallinity, and in some instances with ideal morphology, have been produced by hydrothermal reaction of aluminiosilicate gels. Synthetic kaolinites doped with Mg2+ and Fe3+ were also obtained.

Synthetic kaolinite doped with Fe3+ produced an ESR spectrum at g = 4 identical to spectra observed in natural kaolinites. Following X-irradiation and annealing at ~200°C, synthetic kaolinite doped with Mg2+ exhibited an ESR signal at g = 2·0 identical to a resonance observed in natural kaolinites. It is concluded that the g = 2·0 signal in kaolinite is due to a defect centre stabilized by Mg2+ substitution.

All synthetic and natural kaolinites exhibit an additional resonance at g = 2·0 following X-irradiation which can be repeatedly created and destroyed by irradiation and annealing. This resonance is attributed to defects possibly associated either with the substitution of Al3+ for Si4+ in kaolinite or with lattice vacancies.

Electron spin resonance (ESR) spectroscopy has contributed significantly to the identification and characterization of paramagnetic impurities associated with clays. Following a brief discussion of the general principles of the technique, a review is given of the application of ESR to the study of those paramagnetic species (chiefly iron and radiation-induced lattice defects) located either within the aluminosilicate structure or present as an external impurity phase.

We describe the design and performance of the Engineering Development Array, which is a low-frequency radio telescope comprising 256 dual-polarisation dipole antennas working as a phased array. The Engineering Development Array was conceived of, developed, and deployed in just 18 months via re-use of Square Kilometre Array precursor technology and expertise, specifically from the Murchison Widefield Array radio telescope. Using drift scans and a model for the sky brightness temperature at low frequencies, we have derived the Engineering Development Array’s receiver temperature as a function of frequency. The Engineering Development Array is shown to be sky-noise limited over most of the frequency range measured between 60 and 240 MHz. By using the Engineering Development Array in interferometric mode with the Murchison Widefield Array, we used calibrated visibilities to measure the absolute sensitivity of the array. The measured array sensitivity matches very well with a model based on the array layout and measured receiver temperature. The results demonstrate the practicality and feasibility of using Murchison Widefield Array-style precursor technology for Square Kilometre Array-scale stations. The modular architecture of the Engineering Development Array allows upgrades to the array to be rolled out in a staged approach. Future improvements to the Engineering Development Array include replacing the second stage beamformer with a fully digital system, and to transition to using RF-over-fibre for the signal output from first stage beamformers.

Background: Transient ischemic attack (TIA) and minor stroke are associated with a substantial risk of subsequent stroke; however, there is uncertainty about whether such patients require admission to hospital for their initial management. We used data from a clinical stroke registry to determine the frequency and predictors of hospitalization for TIA or minor stroke across the province of Ontario, Canada. Methods: The Ontario Stroke Registry collects information on a population-based sample of all patients seen in the emergency department with acute stroke or TIA in Ontario. We identified patients with minor ischemic stroke or TIA included in the registry between April 1, 2008, and March 31, 2011, and used multivariable analyses to evaluate predictors of hospitalization. Results: Our study sample included 8540 patients with minor ischemic stroke or TIA, 47.2% of whom were admitted to hospital, with a range of 37.6% to 70.3% across Ontario’s 14 local health integration network regions. Key predictors of admission were preadmission disability, vascular risk factors, presentation with weakness, speech disturbance or prolonged/persistent symptoms, arrival by ambulance, and presentation on a weekend or during periods of emergency department overcrowding. Conclusions: More than one-half of patients with minor stroke or TIA were not admitted to the hospital, and there were wide regional variations in admission patterns. Additional work is needed to provide guidance to health care workers around when to admit such patients and to determine whether discharged patients are receiving appropriate follow-up care.