Upper Urinary Tract Stone: Clinical, Experimental and Biochemical Studies

Clinical, biochemical and experimental studies in upper urinary tract stone have been carried out in more than one thousand patients. The investigation has been conducted during the last eight years in the Urological Department of the Victoria Infirmary. A broad picture of the general incidence and diagnostic findings has been presented with reference to the complete series, the numbers receiving operative and expectant treatment proving to be almost equal. A general increase in the incidence of the disease over the last thirty years has been noted. The purely clinical approach to aetiology has been disappointing, and a satisfactory cause has been shown in a very small proportion of all patients. The factors of possible and doubtful significance have been stated. lack of information about aetiology has been felt at all times to be the main obstacle to progress in prevention and treatment. The natural history of upper urinary tract stone has been studied to provide a standard or "control" series by which the results of operation may be judged, and to fill a gap which clearly exists in our understanding of the disease. The clinical progress of all stones originating in the kidney has been followed to its termination, either in operative removal or natural expulsion. Obstructive potential has been shown to be more important than size per se. Early removal of the obstructive stone has been considered to be its most conservative treatment. A plea, however, has been made for an expectant attitude, with careful supervision in a Stone Clinic in the case of (l) small symptom-free, calyceal stones with normal pyelograms, (2) large symptomless bilateral branched stones, and (3) small ureteric calculi which are making satisfactory progress in the absence of hydronephrosis. It has been shown that more than 80 per cent, of all stones which enter the ureter eventually pass, and that there is therefore no particular virtue in claiming similar results from treatment by endoscopic or open surgical procedures (if these are applied to every case encountered). The late results of operative treatment indicate a depressingly high recurrence rate. Recurrences have been graded as "mild" and "severe", depending on whether or not secondary operation has been necessary. In round figures, one out of every four patients undergoing operative treatment has developed severe recurrence, and the total figure for recurrence has been shown to be somewhere between thirty and fifty per cent. False recurrence, which has not been included in these figures, has been detected in one out of eight patients examined. The factors responsible for, or related to, recurrence have been studied at some length. Nephrolithotomy has been shown to be undesirable on account of its higher mortality rate, the incidence of pseudo- and true recurrence associated with it, and its harmful effect on renal function. Ablation of the kidney has proved to be no guarantee of immunity from recurrence on the opposite side, since the incidence of contralateral recurrence has been the same after nephrectomy and conservative procedures. There has been a steady decrease in recurrence rates in the last three decades. Urinary infection, hyperparathyroidism, hypercal-curia and uncorrected pelvi-ureteric obstruction all have much in common with recurrence, and attention to their treatment, together with complete removal of the stones, give the patient the best early chance of escaping this complication. Long-term preventive measures have been shown to depend, in our present incomplete state of knowledge, on the chemical analysis of the stone, the aim being the production of the maximum solubility of the main crystalloid present. Clinical trials on stone patients and experimental work in animals have failed to confirm that hyaluronidase is valuable in preventing recurrent stone or in reducing the size of those already present in the urinary tract. The place of oestrogens, aluminium hydroxide gel, and salicylates in the prevention of recurrence has been discussed. Comparative studies have indicated that bilateral stone is more serious than the unilateral condition, principally in respect of the post-operative mortality and the late results. (Abstract shortened by ProQuest.)

Fabrication of natural and magnetic slippery surfaces

2019 Summer.Includes bibliographical references.Liquid-infused porous surfaces (LIPS) are a type of low adhesion surfaces. They allow most common solids and liquids to slide off the surface easily. Because of this they are able to reduce the adhesion of food, ice, and even blood platelets to surfaces. As a result, LIPS have applications in reducing food waste, aircraft and powerlines deicing, and hemocompatable implants. However, most LIPS are made of toxic fluorocarbon materials. In this work, in order to eschew toxic fluorocarbon materials, we designed several LIPS made from natural hemp products. The first is an all-natural LIPS made from hemp fibers, which could help reduce or eliminate liquid food waste. The second is an aluminum LIPS that shows excellent anti-icing and de-icing properties. The third is a titanium nanotube LIPS that allows blood to slide off without impinging or clotting. This surface also shows excellent platelet reduction. Finally, we demonstrated a simple way of replicating this LIPS system on multiple metals including copper and steel. Further, we demonstrated a simple fabrication of LIPS on top of the fabricated texture atop a magnetic tape. Magnetic tapes are no longer widely used and they are extremely difficult to dispose of. In this magnetic tape-based LIPS, we were able to use an external magnet to manipulate droplets on the surface of the magnetic tape. This can lead to a microfluidic system with a repurposed substrate and precise manipulation of droplets using a magnetic field

Entrainment of fine sediments by turbulent flows

A study was made of the means by which turbulent flows entrain sediment grains from alluvial stream beds. Entrainment was considered to include both the initiation of sediment motion and the suspension of grains by the flow. Observations of grain motion induced by turbulent flows led to the formulation of an entrainment hypothesis. It was based on the concept of turbulent eddies disrupting the viscous sublayer and impinging directly onto the grain surface. It is suggested that entrainment results from the interaction between fluid elements within an eddy and the sediment grains. A pulsating jet was used to simulate the flow conditions in a turbulent boundary layer. Evidence is presented to establish the validity of this representation. Experiments were made to determine the dependence of jet strength, defined below, upon sediment and fluid properties. For a given sediment and fluid, and fixed jet geometry there were two critical values of jet strength: one at which grains started to roll across the bed, and one at which grains were projected up from the bed. The jet strength, K, is a function of the pulse frequency, [omega] , and the pulse amplitude, A, defined by K=A[omega]^-s where s is the slope of a plot of log A against log [omega]. Pulse amplitude is equal to the volume of fluid ejected at each pulse divided by the cross sectional area of the jet tube. Dimensional analysis was used to determine the parameters by which the data from the experiments could be correlated. Based on this, a method was devised for computing the pulse amplitude and frequency necessary either to move or project grains from the bed for any specified fluid and sediment combination. Experiments made in a laboratory flume with a turbulent flow over a sediment bed are described. Dye injection was used to show the presence, in a turbulent boundary layer, of two important aspects of the pulsating jet model and the impinging eddy hypothesis. These were the intermittent nature of the sublayer and the presence of velocities with vertical components adjacent to the sediment bed. A discussion of flow conditions, and the resultant grain motion, that occurred over sediment beds of different form is given. The observed effects of the sediment and fluid interaction are explained, in each case, in terms of the entrainment hypothesis. The study does not suggest that the proposed entrainment mechanism is the only one by which grains can be entrained. However, in the writer's opinion, the evidence presented strongly suggests that the impingement of turbulent eddies onto a sediment bed plays a dominant role in the process

Affective Problems in Writing

This study sought to determine if tests were available that would allow professors and instructors of College Writing to identify students with differing personality types and attitudes about writing