The Application of Infrared Imaging and Optical Coherence Tomography of the Lacrimal Punctum in Patients Undergoing Punctoplasty for Epiphora

Purpose To determine the application of imaging the stenotic lacrimal punctum with infrared photographs and optical coherence tomography (OCT) and to identify characteristics of the lacrimal punctum in patients who benefit from punctoplasty. Design Case-control study. Participants Twenty patients with epiphora who were listed for punctoplasty and 20 healthy controls. Methods Prospectively, 20 patients listed for punctoplasty were asked to rate their epiphora, using the Munk score, before and after punctoplasty. They also underwent preoperative OCT and infrared imaging of the affected punctum. They were divided into 2 groups, depending on whether the epiphora improved, and were compared with 20 healthy controls. Main Outcome Measures Measurements of puncta from infrared and OCT images were obtained along with Munk scores of patient epiphora. Results The infrared image measurements were significantly smaller in those patients whose epiphora improved compared with those whose did not in both the area of the punctal aperture and in the maximum punctal diameter. Additionally, those patients with improvement in epiphora had a significantly smaller preoperative punctal diameter at 100 μm depth on OCT compared with healthy controls; this was not observed in patients whose epiphora failed to improve. There was no significant difference in the punctum diameter among the 3 groups at the punctum surface entrance or at 500 μm depth. Patients with epiphora had a higher tear meniscus within the punctum compared with healthy controls. Conclusions Lacrimal punctum infrared and OCT imaging may be helpful in predicting patients more likely to benefit symptomatically from punctoplasty, with patients with smaller puncta having greater symptomatic improvement. However, the results suggest that inner punctum diameter (not readily measurable by slit-lamp examination), rather than the surface diameter, is correlated with outcome. Additionally, OCT measurements of the tear meniscus height within the punctum may be related to the degree of epiphora

Characterizing the Occluded Lacrimal Punctum Using Anterior Segment Optical Coherence Tomography.

PURPOSE: Epiphora is sometimes associated with an absent or occluded lacrimal drainage punctum (or puncta). This study uses noninvasive "enhanced depth" anterior segment optical coherence tomography (OCT) to give improved characterization and understanding of absent or fully occluded puncta and the underlying canaliculus. METHODS: Anterior segment spectral domain OCT images were collected prospectively from 9 lower puncta of 6 patients with epiphora and absent or fully occluded puncta, not amenable to dilation in clinic, to see if a canaliculus was visible on OCT imaging below the occluded punctum. RESULTS: An epithelial lined canalicular lumen was visible on OCT in 4 lower eyelid puncta from 2 patients and OCT identified 80% (4/5) of the canaliculi that were located on microscope-assisted punctal exploration. These lumens were seen within 580 μm depth from the eyelid margin surface. A half of the eyes in which a canaliculus was identified on OCT (the 2 eyes in a single patient) had resolution of epiphora following punctoplasty, and the other patient was found to have coexisting nasolacrimal duct stenosis and required later dacryocystorhinostomy. The positive predictive value for identifying a canaliculus on lower eyelid punctal exploration in acquired complete punctal occlusion (excluding the congenital case) was 1, with a negative predictive value of 1. CONCLUSIONS: This study demonstrates that canaliculi can be imaged with OCT where formal access is precluded by an occluded punctum. This noninvasive investigation might help predict the likelihood of successful retrieval of a canaliculus at surgical exploration

Investigating freeway traffic hypercongestion between an on-ramp and its immediate upstream off-ramp

This paper applies the freeway traffic congestion dynamics proposed in Laval and Leclercq [2010. “Continuum Approximation for Congestion Dynamics Along Freeway Corridors.” Transportation Science 44 (1): 87–97] but with a modified distribution scheme of freeway merging flows to investigation of traffic hypercongestion on a freeway between an on-ramp and its immediate upstream off-ramp. The reason to make this modification is that the original merging scheme of this dynamics is found to possibly give undesired full priority to the traffic from the on-ramp and also occasionally make the resulting flow going through the merge greater than the available capacity. Traffic hypercongestion in this paper refers to a state where speed and flow change in the same direction as density varies. A homogeneous freeway segment chosen for this investigation includes an on-ramp and an off-ramp, which may correspond to a freeway passing by a city or town, with an off-ramp lying upstream towards the city and an on-ramp downstream. The entry flow from the upstream approach of the freeway was fixed and constant within the time horizon while both deterministic and random on-ramp inflow rates were used in this investigation. Then the formation and dissipation of traffic hypercongestion is investigated as on-ramp demand and off-ramp departure profiles vary. The first finding of this investigation is that the density in the hypercongestion area behind the merge never reached the jam density. Second, the hypercongested area continued to grow as long as the sum of the demand from the upstream of the freeway and that from the on-ramp was greater than the available capacity at the merge. Third, as long as the rate of flow leaving from the freeway via the off-ramp was not smaller than the entry flow rates from the on-ramp, no hypercongestion had been observed. In addition, in analysing the numerical results, a series of discussions was carried out to build the linkage between the on- and off-ramp flow profiles and the generated and attracted demand of the city plus its adjacent area the two ramps served for; these discussions suggest that the balanced generated and attracted demand of the city plus its adjacent area can reduce or even remove traffic hypercongestion behind the merge on the chosen freeway segment.postprin

Particle size emissions from PVC electrical cable fires

Electrical cables are in every building and form a significant part of fire loads and can through electrical faults be the first item burnt in some fires. PVC insulated cables are still quite common in buildings and this work investigates Prysmian PVC cables. Deaths and injuries in fires are dominated by the influence of toxic smoke emissions and most of the work on the hazards of smoke are concerned with the toxic gases such as CO. However, fires are large producers of particulate material at levels over 1000 times that in controlled combustion and there is little knowledge of the role of ultra-fine particles in fires and none at all for electrical cable fires. The cone calorimeter fire material testing equipment was used in the present work, which is an ideal test procedure for particle size measurement, as controlled dilution (100/1) of the fire products occurs which enabled diluted samples to be used for particulate number measurement. The Cambustion DMS500 transient particle size analyser was used to determine the particle size distribution. The cone calorimeter uses a 100mm square test specimen and this was filled with 10 100mm lengths of the PVC cable. The test specimen was on a load cell so that the mass burn rate was determined. The cone calorimeter ignites the specimen using a conical electrical heater that is calibrated to achieve a control radiant heat flux on the test specimen, which was 35 kW/m2 in the present work. The fire occurred in a restricted air supply with an insulated air box around the 100mm square test fire. A chimney on the conical heater exit was used to obtain a raw gas sample for toxic gas analysis using a heated Gasmet FTIR. For gases dilution is undesirable as oxidation of the toxic gases may occur. For particles the chimney temperature was too low for carbon oxidation to be significant. The dilution process also condenses unburned hydrocarbons and carbonyl species, which may form nano aerosols and these may be the source of the 10nm particles measured in the present work. HCl is a major product of PVC fires and hence hydrochloric acid aerosols are likely in the particulate measurements. In previous work of the authors, PVC cable fires were investigated with free ventilation and HCl yields of about 50% were measured with Acrolein at 5% yield and Formaldyhyde at 3%. Thus there are plenty of liquid aerosol possible in the diluted products of PVC fires. The results showed a large nuclei number peak at about 10nm. The coarse particle peak only started after flaming combustion occurred and this was initially at 200nm, which increased to 300nm after 1000s. The 10nm peak was high for the first 200s, then dropped dramatically and slowly reformed later in the fire and at the end of the fire was very high with a low coarse particle peak. The FTIR gas species will be used to speculate on the likely composition of the nanoaerosols as a function of time in the fire

CELLmicrocosmos 2.2: advancements and applications in modeling of three-dimensional PDB membranes

Sommer B, Dingersen T, Schneider S, Rubert S, Gamroth C. CELLmicrocosmos 2.2: advancements and applications in modeling of three-dimensional PDB membranes (Conference Abstract). In: Journal of Cheminformatics. Journal of Cheminformatics. Vol 2(Suppl 1):O21. Springer Science and Business Media LLC; 2010

Observing Brownian motion in vibration-fluidized granular matter

At the beginning of last century, Gerlach and Lehrer observed the rotational Brownian motion of a very fine wire immersed in an equilibrium environment, a gas. This simple experiment eventually permitted the full development of one of the most important ideas of equilibrium statistical mechanics: the very complicated many-particle problem of a large number of molecules colliding with the wire, can be represented by two macroscopic parameters only, namely viscosity and the temperature. Can this idea, mathematically developed in the so-called Langevin model and the fluctuation-dissipation theorem be used to describe systems that are far from equilibrium? Here we address the question and reproduce the Gerlach and Lehrer experiment in an archetype non-equilibrium system, by immersing a sensitive torsion oscillator in a granular system of millimetre-size grains, fluidized by strong external vibrations. The vibro-fluidized granular medium is a driven environment, with continuous injection and dissipation of energy, and the immersed oscillator can be seen as analogous to an elastically bound Brownian particle. We show, by measuring the noise and the susceptibility, that the experiment can be treated, in first approximation, with the same formalism as in the equilibrium case, giving experimental access to a ''granular viscosity'' and an ''effective temperature'', however anisotropic and inhomogeneous, and yielding the surprising result that the vibro-fluidized granular matter behaves as a ''thermal'' bath satisfying a fluctuation-dissipation relation

Estimating the cost-effectiveness of detecting cases of chronic hepatitis C infection on reception into prison

Background In England and Wales where less than 1% of the population are Injecting drug users (IDUs), 97% of HCV reports are attributed to injecting drug use. As over 60% of the IDU population will have been imprisoned by the age of 30 years, prison may provide a good location in which to offer HCV screening and treatment. The aim of this work is to examine the cost effectiveness of a number of alternative HCV case-finding strategies on prison reception Methods A decision analysis model embedded in a model of the flow of IDUs through prison was used to estimate the cost effectiveness of a number of alternative case-finding strategies. The model estimates the average cost of identifying a new case of HCV from the perspective of the health care provider and how these estimates may evolve over time. Results The results suggest that administering verbal screening for a past positive HCV test and for ever having engaged in illicit drug use prior to the administering of ELISA and PCR tests can have a significant impact on the cost effectiveness of HCV case-finding strategies on prison reception; the discounted cost in 2017 being £2,102 per new HCV case detected compared to £3,107 when no verbal screening is employed. Conclusion The work here demonstrates the importance of targeting those individuals that have ever engaged in illicit drug use for HCV testing in prisons, these individuals can then be targeted for future intervention measures such as treatment or monitored to prevent future transmission

A systematic approach for the accurate non-invasive estimation of blood glucose utilizing a novel light-tissue interaction adaptive modelling scheme

Diabetes is one of the biggest health challenges of the 21st century. The obesity epidemic, sedentary lifestyles and an ageing population mean prevalence of the condition is currently doubling every generation. Diabetes is associated with serious chronic ill health, disability and premature mortality. Long-term complications including heart disease, stroke, blindness, kidney disease and amputations, make the greatest contribution to the costs of diabetes care. Many of these long-term effects could be avoided with earlier, more effective monitoring and treatment. Currently, blood glucose can only be monitored through the use of invasive techniques. To date there is no widely accepted and readily available non-invasive monitoring technique to measure blood glucose despite the many attempts. This paper challenges one of the most difficult non-invasive monitoring techniques, that of blood glucose, and proposes a new novel approach that will enable the accurate, and calibration free estimation of glucose concentration in blood. This approach is based on spectroscopic techniques and a new adaptive modelling scheme. The theoretical implementation and the effectiveness of the adaptive modelling scheme for this application has been described and a detailed mathematical evaluation has been employed to prove that such a scheme has the capability of extracting accurately the concentration of glucose from a complex biological media