Top Slice Research Articles

Noninvasive Gadolinium-Enhanced Three Dimensional Computed Tomography Coronary Angiography

Although the use of gadolinium (Gd)-based contrast agents for angiographic studies of abdominal aorta, renal vasculature, and digital subtraction angiography has been reported, no studies have shown their diagnostic efficacy and image quality in coronary computed tomography angiography (CTA). The aim of this study is to evaluate the image quality of Gd-based contrast agents during coronary CTA. A phantom study was done to evaluate the attenuation of serial dilutions of Gd and iodinated agents. This study was done on a 64-slice multirow detector CT (MDCT) scanner and e-speed scanner and CT attenuation Hounsfield units (CTHU) were compared. We evaluated 35 consecutive patients who underwent Gd-enhanced CTA. CTHU of aorta was measured at first, mid, and lowest slice levels with and without contrast administration. The image quality was graded on the basis of visualization of the coronary arteries (scale I-III; III demonstrating diagnostic image quality of the distal-most vessels). In a substudy, four patients with borderline renal insufficiency underwent CTA using Gd and iodinated contrast agents admixed in a 50:50 ratio. The phantom study showed that enhancement of various dilutions of Gd and iodine resulted in near identical CTHU with both e-speed and 64-slice scanners (r(2) > or = 0.997). Mean CTHU with contrast at the top slice was 116 HU, at middle slice was 125 HU, and at the lower slice was 93 (111.14 +/- 22). Quality evaluation showed 2 grade III, 9 grade II, and 24 grade I images (average quality of images 1.35). Mean CTHU was 222. Gd-enhanced contrast medium provides adequate enhancement of coronary vasculature, allowing for diagnostic evaluation of coronary arteries with new CT systems. Use of newer generations of multirow detector CT scanners should further enhance the quality of images.

G Protein-induced Trafficking of Voltage-dependent Calcium Channels

Calcium channels are well known targets for inhibition by G protein-coupled receptors, and multiple forms of inhibition have been described. Here we report a novel mechanism for G protein-mediated modulation of neuronal voltage-dependent calcium channels that involves the destabilization and subsequent removal of calcium channels from the plasma membrane. Imaging experiments in living sensory neurons show that, within seconds of receptor activation, calcium channels are cleared from the membrane and sequestered in clathrin-coated vesicles. Disruption of the L1-CAM-ankyrin B complex with the calcium channel mimics transmitter-induced trafficking of the channels, reduces calcium influx, and decreases exocytosis. Our results suggest that G protein-induced removal of plasma membrane calcium channels is a consequence of disrupting channel-cytoskeleton interactions and might represent a novel mechanism of presynaptic inhibition.

New Frames for Old Masters. An overview of the British Library's Acetate Transfer programme

After the second International Round Table on acetate microfilm, the British Library decided to top slice from its annual preservation budget, £200k every year for five years to address its cellulose acetate problem. We did this by instigating a programme of base transfer, transferring the frames from the old acetate masters onto new polyester stock. It proved to be quite a challenge and this paper reproduces largely the presentation given at CAMF, which was an overview of the background to the project and its progress. Twenty three million feet. Not a centipedes' picnic, but the amount of acetate microfilm the British Library has in its collections. A sobering statistic. But what does it really mean? Well, if we rolled it all out, it would be enough to stretch all the way from New York to Moscow. Or, for the more vertically minded, if we piled it all up, it would be taller than not just 1 Mount Everest, but 809. That represents a pretty huge problem whichever way you look at it and my first thought when it was handed to me was, 'where on earth do we start?'

Implementation and validation of a 3-dimensional deformable registration algorithm for targeted prostate cancer radiotherapy

The daily position and shape changes of the prostate pose an obstacle to reducing the safety margin and decreasing radiation to the surrounding normal tissues during prostate cancer external beam radiotherapy. The daily prostate deformation also complicates accurate dose tracking. The uncertainty in dosimetry is further accentuated when intraprostatic targets based on molecular imaging need to be treated to a desired dose. Against this background, we have implemented and validated a 3-dimensional deformable registration algorithm to aid targeted prostate radiotherapy. We implemented and enhanced a deformable 3-dimensional image registration algorithm. This algorithm performs registration between two computed tomography (CT) images based on iteratively minimizing the difference in their image intensities (CT numbers). We used three methods to quantify the accuracy of the algorithm. First, a deformed pelvic CT set was created using a mathematically transformed set of patient pelvic CT images that was obtained with an in-room CT scanner during a course of radiotherapy. The precise voxel-to-voxel correspondence was available from the known mathematical transformation. We measured the accuracy of the deformable registration algorithm in registering the original pelvic CT set to the deformed CT set. In the second test, a custom-made deformable pelvic phantom was used. The phantom contains bony structures, and deformable bladder, rectum and prostate. Two separate CT sets of the phantom were obtained with an endorectal balloon inserted into the rectum with or without inflation with 100 cc of air. To simulate intraprostatic targets, 23 CT-opaque seeds were embedded into the prostate. We measured the accuracy of the algorithm in registering the images of the phantom with and without deformation. Lastly, two sets of pelvic CT images of the same patient were obtained on two different days during the course of treatment. These CTs were 9 days apart. We tested the goodness of the registration. In each case, correlation coefficients that measure the similarity of CT image intensities of two CT data sets were computed for a 256 × 256 − 120 cubic mm region of interest around the prostate. Correlation coefficients were computed at each CT slice as well as globally. Based on point-to-point comparison between the mathematically transformed and the registered CT sets, we found the errors were as follows: in x (lateral) direction: −0.10 ± 0.52mm; y (anterior-posterior) direction: 0.10 ± 1.11mm; and z (superior-inferior) direction: −0.21 ± 1.10mm. The corresponding 3 dimensional error was 0.57 ± 1.56mm. The overall correlation coefficient improved from 0.971 to 0.997 with the deformable registration. Using the deformable pelvic phantom, the range of shifts of the intraprostatic seeds in space created by inflating the endorectal balloon with 100 cc of air was 4.69 mm to 9.54 mm. The corresponding mean (S.D.) shift due to deformation for the 23 seeds was 6.81(±1.33) mm. The range of error in registering the seeds was 0.23 mm to 3 mm. The corresponding mean (S.D.)error was 0.86 ± 0.53mm. The correlation coefficient improved from 0.979 to 0.993 with deformable registration. Using deformable registration on the two patient CT sets obtained on two separate CT sessions, the correlation coefficient improved from 0.945 to 0.972; discounting the top and bottom CT slices that did not have sufficient information for 3-D registration, the correlation coefficient improved from 0.945 to 0.989 for the remaining 38 CT slices. Our 3-dimensional deformable registration algorithm performs accurate registration between the reference pelvic images and its deformed counterparts. The absolute registration accuracy is in the order of 1mm. In particular, the algorithm tracked the intraprostatic seeds accurately. We argue that our algorithm may aid in optimizing dose calculation and delivery for prostate radiotherapy. It may also help to allow daily mapping of intraprostatic targets for prostate cancer radiotherapy

MBR의 비례 관계를 이용한 영상 보간이 적용된 뇌 MR 영상의 3차원 가시화

본 연구에서는 뇌 MR 영상의 3차원 가시화를 위해 여러 단면의 원영상을 사용하지 않고, 적은 수의 횡단면 영상만을 이용하여 보간 영상을 생성하는 방법에 대해 제안한다. 이 과정에서의 핵심인 영상 보간을 위해 우선 3차원으로 재구성하고자 하는 관심영역을 분할하고, 분할된 관심 영역들의 경계와 MBR(Minimum Bounding Rectangle) 정보를 추출한다. 그리고 보간하고자 하는 층의 영상 크기는 분할된 관심영역의 상ㆍ하층 각각 두 영상들의 MBR 크기 변화율로 결정하고, 이를 기반으로 분할된 관심 영역의 영상내에서 해당 화소를 찾고, 입방 보간법을 통해 검출된 각 화소의 명암 가중치를 부여하여 보간 영상의 화소 명암치를 산출한다. 최종적으로는 원영상에서 분할한 관심영역 및 생성된 관심영역의 보간 영상들에서 특징점 정보와 3차원 복셀을 추출하여 3차원으로 재구성한다. In this paper, we propose a new method in which interpolation images are created by using a small number of axiai T2-weighted images instead of using many sectional images for 3D visualization of brain MR images. For image Interpolation, an important part of this process, we first segment a region of interest (ROI) that we wish to apply 3D reconstruction and extract the boundaries of segmented ROIs and MBR information. After the image size of interpolation layer is determined according to the changing rate of MBR size between top slice and bottom slice of segmented ROI, we find the corresponding pixels in segmented ROI images. Then we calculate a pixel's intensity of interpolation image by assigning to each pixel intensity weights detected by cube interpolation method. Finally, 3D reconstruction is accomplished by exploiting feature points and 3D voxels in the created interpolation images.

Effects of broiler breast meat thickness and background on color measurements

Experiments were conducted to determine the influence of broiler and turkey breast meat thickness and background on breast meat color measurements. Broiler breast fillets were sliced into two 1 cm thick slices and the turkey breast fillets into three 1 cm slices. Color values for lightness (L*), redness (a*), and yellowness (b*) were measured on the same top slice singly or while placed over the corresponding broiler and turkey slices. Color was measured in triplicate while the fillets were placed on the following backgrounds: plastic-coated white paper, white nylon, aluminum foil, black plastic, and a yellow commercial packaging tray (broiler only). Sample thickness significantly affected L*, a*, and b* values of turkey and chicken. Increased breast meat thickness resulted in lower L*, a*, and b5 values. Increased turkey meat thickness from 1 to 2 cm resulted in lower a* and b* values; however, only lower L* values were observed, with sample thickness increased from 1 to 3 cm. No differences in meat color were found when increasing turkey meat sample thickness from 2 to 3 cm. Background had a significant effect on single (1 cm) broiler and turkey meat color measurements but did not influence the color readings of the thicker multiple slice samples. These results indicate that the application of machine vision or in-line color measurement systems may have to take into account breast meat thickness, and in thinner samples, background color.

Crystal ion slicing of domain microengineered electro-optic devices on lithium niobate

We report the successful fabrication of 6 μn thick slices from a ferroelectric domain micro-engineered LiNbO3 wafer device using the crystal ion slicing technique. The device was created by micropatterning ferroelectric domains in a bulk 0.3 mm thick wafer of z-cut LiNbO3, followed by ion-implanting with high energy He+ ions to create a damage layer at a well defined depth from the surface. Etching away this damaged layer in dilute hydrofluoric acid results in a liftoff of the top slice in which the ferroelectric domain patterns are left intact.

Ultrathin Slices of Ferroelectric Domain-Patterned Lithium Niobate by Crystal Ion Slicing

ABSTRACTWe report the successful fabrication of 6 µm thick slices from a ferroelectric domain micro-engineered LiNbO3 wafer device using the crystal ion slicing technique. The device was created by micropatterning ferroelectric domains in a bulk 0.3 mm thick wafer of z-cut LiNbO3, followed by ion-implanting with 3.8 MeV He+ ions to a fluence 5 × 10+16 ions/cm2 to create a damage layer at a well defined depth from the surface. Etching away this damaged layer in dilute hydrofluoric acid results in a liftoff of the top slice in which the ferroelectric domain patterns are left intact. The influence of annealing conditions on liftoff time and depth of etch lines was studied. Helium-Neon laser light was successfully coupled into the device. Due to unintentional breakage of the polished input and output faces, the electro-optic scanning performance has not been characterized so far.

In vitro regeneration and Agrobacterium mediated transformation in gladiolus

SummaryIn vitro regeneration and transformation studies were conducted on two cultivars of gladiolus. Cormels of 1.0 to 1.5 cm diameter cut into 2–3 mm thick slices of top, middle and bottom, and in vitro derived bisected shoot tips were used as explants on MS medium supplemented with 18.6 μM kinetin for multiple shoot induction. Amongst the cormel slices, the top slice gave better shoot induction response of 89% with an average of 2.4 shoots per explant over both cultivars. In vitro derived bisected shoot tips were inoculated on the medium oriented cut-side up, cut-side down and vertically both with and without the cormel base attached. Bisected shoot tips without attached cormel base and inoculated in the cut-side down orientation showed an average of 90% shooting response. In vitro derived shoot tips were used as explants for transformation. Explants were wounded by scalpel and particle bombardment with 1.6 μm naked gold particles by the biolistic delivery system. The wounded explants, after 3 d of recovery period, were co-cultivated with Agrobacterium strain LBA4404 harbouring the binary vectors pBI141 and pTOK233 which contained gus reporter gene with rice actin and 35S promoters respectively. GUS expression frequencies of 5.3% and 23% was obtained from scalpel and particle bombardment wounded explants, respectively. Particle wounded explants showed an average of 63 and 103 GUS spots when co-cultivated with pBI141 and pTOK233 binary vectors respectively. Explants co-cultivated with pBI141, after three weeks of selection on antibiotic containing medium showed blue streaks of GUS expression. It was concluded that Agrobacterium could infect the monocot gladiolus and transform the tissue eficiently when tissues were prewounded with naked gold particles delivered by particle gun.

Subsea Channels and Incidence of Thermogenic Hydrocarbons in the Mid-proximal Bengal Fan, West of the Andaman-Nicobar Islands

Mid-fan areas in the Bay of Bengal to the west of the Andaman-Nicobar Islands and to the east of the 90 E ridge display remarkable channel-levee and interlevee characteristics over the seabed. These subsea channels at 3,000 m or more water depth have specific orientations along NNE or NNW. Most of these major and minor channels are at present inactive, except one running along the eastern part of the area following the reported subduction suture (Currey et al., 1979). The other channels in the western part retain the configuration of a floor-bank combination but are covered with a thin deposition of pelagic organisms without any significant terrigenous inputs to a depth of around 25 cm below the seabed. On the other hand, the active channel to the east is filled with continuous hemipelagic to terrigenous inputs up to at least 1.5 m bsf. The pelagic organisms of the upper 25 cm of seabed over the inactive channels as well as in their banks and interlevee areas are mainly represented by foraminiferal tests and thus constitute foraminiferal ooze. Most of the seafloor is covered by such ooze except in the easternmost part, where the active channel brings a terrigenous influx in the form of turbidites. The fan deposition has been restricted to the easternmost active channel since the early Holocene. The age of the pelagites that constitute the 25-cm top sediment slice is assumed to represent about 8,000 years, calculated at the rate of deposition of 3 cm 1,000 years (Kennet, 1982). Thus, most of the western seabed has not experienced any fan deposition during the last 8,000 years. However, below 25 cm, the entire area is seen to have experienced fan deposition as evidenced by occurrence of terrigenous silt and clay. Significantly, incidence of thermogenic hydrocarbons is proved in the levee-in terlevee complexes of the central part. Being closer to the subduction zone, gas seepages through pervasive fissures are perhaps more pronounced here.

Seventh survey of staffing in cardiology within the UK 1991

<b>The Seventh Survey of Staffing in Cardiology was conducted with an index date of 31 July 1991. At that time the total number of posts for cardiologists in England and Wales, defined as individuals trained in the specialty and spending at least 40% of their professional time working in it, was 340. Ten individuals worked part time only, making 335 whole time equivalent posts. This number increased from 1990 by 15 (4·7%). There were 67 cardiologists in Scotland and Northern Ireland, making a total for the United Kingdom of 407 posts (402 whole time equivalents). Sixteen Districts in England and Wales had no cardiologist at the time of the survey, and 31 other Districts had less than seven visiting sessions each week. The situation had not improved since the 1990 survey. The population of these 47 Districts is nearly nine million. Scotland had almost 800 000 additional people served by Health Boards without resident cardiologists.</b> <b>The number of senior registrars and lecturers is inadequate to provide a full period of training for most who advance to consultant status, and the situation will worsen from 1995 onwards. A major problem has been a top slice of 10 posts for a research allocation, few of which are occupied by individuals seeking a career in the specialty. These posts should be redesignated to increase training opportunities to counter the present shortfall and facilitate an expansion in consultant posts of at least 5% per annum over the next decade.</b>

Mortgage Indemnities – A Risk/Reward Arbitrage?

Gives background to Commercial Mortgage Indemnity (CMI). Explains the concept and purpose of CMI. Explains: scope of cover, indemnities vs guarantees, “top slice” CMI, total cover, underwriting criteria and how to make a claim. Concludes that whereas CMI is sensitive to market conditions, capacity will expand with returning confidence.

Release and provision for continuing education

fulERICAN NURSES ASSOCIATION \VITHIN AND WITHOUT the nursing profession there is an increased awareness of the importance and need for continuing education. It is quite 'specifically referred to in a number of official publications including the Report of the Committee on Nursing (1972) and that of the Royal Commission as well as a report of the National Staff Committee for Nurses and Midwives. One might be excused for naively assuming that the level of activity might be commensurate with this degree of support. In fact, the reality falls a good deal short of these aspirations. I contacted ' various colleagues in order to ascertain just how much was spent on continuing education in their Health Authority. Admittedly it was a small sample but the answers ranged from £9 to £167 depending on the number of qualified staff. While it is appreciated that some Regional Health Authorities top slice some funding for such activities as JBCNS and health visitor training, this shows a remarkable variation. It is still possible for a person to qualify as a state registered nurse and assume, in a relatively short space of time, the rank of ward sister. She is then under no obligation whatsoever to undertake any continuing education. When one considers the cost to the National Health Service of training midwives given that only one in five of trained midwives are delivering babies seven years after qualifying and that less than half never actually practise as midwives. There will be some who question whether this is a luxury the NHS can afford. Certainly, the statement that 'opportunities for continuing education should be available as of right ... ' ought properly to be set against a backcloth which includes reference to the associated costs and benefits. \Vithin the NHS today we cannot afford to waste any resources and we must

Polymetamorphism and structures in the Superior Province near the Grenville Front in south-central Quebec

Abstract Polymetamorphic metabasalts and metasediments of the Villebon area are interpreted as a sequence representing the top slice of oceanic crust covered by a layer of island-arc volcanic products and turbidites in a back-arc environment during pre-Kenoran times. They were folded and metamorphosed during the Kenoran Orogeny. During the Aphebian, renewed sedimentation took place on an Atlantic-type continental edge, whereafter during the Hudsonian Orogeny part of the Superior craton slid on top of the sediment wedge over a low rheidity migmatized layer. Later westward thrusting of Grenvillian deposits, together with their basement, caused tilting and steepening of preexisting Kenoran and Hudsonian structures. The decollement plane, previously mapped as the Grenville Front, is a Hudsonian Feature; the true Grenville Front is probably located more eastward.

Theory of angular dependence in electron emission from surfaces: Application to secondary emission from Al(001) and Al(110)

The model of electron emission derived tor Auger emission in a previous paper, is extended to the study of angular resolved secondary emission and applied to the description of experimental results obtained on Al(001) and Al(110). We include exactly all the final state effects, and we give a simple description for the source wavefield which is taken as a set of plane waves created incoherently at a given depth and with any possible wavevector coupled to the direction of observation. Having no specific model for the cascade processes at the origin of the source wavefield, we have taken a uniform distribution of sources. The experimental data have been taken at a primary energy at 350 eV and at normal incidence, such that the anisotropy depends no longer on the incidence conditions. On one hand the polar angle plots are dominated by a cos 2θ like dependence; on the other hand the modulations on polar or azimuthal plots are found less than 10%. Both effects are well accounted for by our model. As far as the correlation of experimental and calculated fine structures is concerned, a close examination of the individual contributions from deeper and deeper crystal slices suggests a non-uniform distribution of sources normal to the surface, the top and first slice having a small contribution.