Vessel Dimensions Research Articles

Forecasting of quay line activity with neural networks

This paper presents a generalised regression neural network (GRNN) to forecast the activity of the North Quay at the port of Callao (Peru). To the author's knowledge, this is the first application of artificial neural network theory to container terminals in South America. On the basis of service characteristics, operating profiles, and dimension of vessels, the model examines the berthing line. Five numerical variables are used to estimate one dependent variable. The results achieved are satisfactory and the model built up using neural network theory is able to estimate the staying time of vessels in port.

Определение главных размерений маломерных глиссирующих судов в начальной стадии проектирования

Определение главных размерений маломерных глиссирующих судов в начальной стадии проектирования

Using IVUS to improve treatment of complex lesions in the femoropopliteal arteries

Despite rapid advances in in peripheral endovascular therapy over the last 15 years, the rate of restenosis and revascularization in the femoropopliteal arteries remains high. This is particularly the case for more complex lesions, such as longer lesions, those with severe calcification and chronic total occlusions (CTO). The recognised limitations of angiography, particularly the planar and luminal nature of the imaging, result in incomplete assessment of lesion characteristics which may well contribute to problems with achieving satisfactory outcomes. Intravascular ultrasound (IVUS) is a fundamentally different mode of imaging to angiography and is able to produce high quality imaging of the entire artery rather than just the lumen. IVUS provides a range of imaging parameters, many of which are unique to this form of imaging and are unobtainable with angiography. IVUS can therefore assist with a more complete characterisation of the artery and lesion beyond the luminal silhouette and diameters provided by angiography. In this presentation, the role of intravascular imaging (IVUS) in treating complex femoropopliteal lesions will be reviewed, drawing on more than five years’ experience with this technology. The value of IVUS both before and after treatment will be discussed. This will include how pre-treatment IVUS imaging can assist selection of the most appropriate treatment methods by providing accurate assessment of vessel dimensions, length of the diseased segment, severity of calcification, presence of negative remodelling and the degree of plaque eccentricity. This information can inform the choice of treatment technology as well as optimising device size and the length of treatment. IVUS can also provide unique information after initial treatment. This includes accurate measurement of minimum lumen size post angioplasty and stenting, the presence of dissection and the effects of atherectomy, including assessment of the effectiveness of plaque removal and identification of vessel wall damage. IVUS imaging is simple, quick and safe to use during endovascular interventions and can provide unique information that can supplement standard angiographic imaging and help optimise treatments.

Aspects of ice engineering for the aims of construction of the transport infrastructure and reconnaissance drilling in the Arctic

Starting from the mid 2000-s the increase of sustained development of the Russian Arctic is observed, in many cases the technologies using the ice cover as an infrastructure element and the ice as the construction materials are used. In the present time the different approaches of use of natural and artificial ice for applied tasks on the Arctic offshore exist. For example, the clearance of the upper surface of ice from snow and ridges is used for the purposes of the vessel unloading on the fast ice or constructing the airstrips on the drifting ice cover. In case of insufficient thickness of the level ice the latter is increased by the means of preliminary freezing (natural on the bottom side of ice and artificial by pouring the fresh or saline water on the upper surface). By constructing the artificial ice islands the ice body is made by spraying the sea water with the partial freezing of the water drops in the air and further freezing of the 2-phase elements (i.e. ice crystals in the liquid film) on the surface of the ice cover. The problem of cracks in the ice cover is solved by different means according to the proper task. When it is possible, the cracks are “healed”— i.e. are filled with the snow and ice gravel and then freezed. In case of impossibility of use of such method (for example — presence of tidal cracks or relatively high air temperature) the cracks are overlapped with the help of different covers made of different materials and of different sizes. The promising trend of ice technology is involving the reinforced or composite ice, having the increased strength, into the ice engineering practice. By unloading the cargo ships on the fast ice the ice strength is decreased locally for the purpose of easy berthing of the vessel with safekeeping the original strength of the surrounding ice for the aims of the vessel unloading. This problem is solved by creating the system of notches in the ice cover according to the vessel dimensions. The specialized hydrometeorological support on every stage of the ice engineering operation is an essential element of the ice engineering activities on the ice cover of lakes, rivers and seas.

Modeling Growth of Tumors and Their Spreading Behavior Using Mathematical Functions.

Computer simulations of the spread of malignant tumor cells in an entire organism provide important insights into the mechanisms of metastatic progression. Key elements for the usefulness of these models are the adequate selection of appropriate mathematical models describing the tumor growth and its parametrization as well as a proper choice of the fractal dimension of the blood vessels in the primary tumor. In addition, survival in the bloodstream and evasion into the connective spaces of the target organ of the future metastasis have to be modeled. Determination of these from experimental models is complicated by systematic and unsystematic experimental errors which are difficult to assess. In this chapter, we demonstrate how to select the best-suited mathematical function to describe tumor growth for experimental xenograft mouse tumor models and how to parametrize them. Common pitfalls and problems are described as well as methods to avoid them.

Intralesional Macular Atrophy in Anti–Vascular Endothelial Growth Factor Therapy for Age-Related Macular Degeneration in the IVAN Trial

To report on the development and progression of macular atrophy (MA) and its relationship with morphologic and functional measures in study and fellow eyes in the Inhibition of vascular endothelial growth factor (VEGF) in Age-related Choroidal Neovascularisation trial. Reading center analysis of data from a randomized controlled trial. Participants with previously untreated neovascular age-related macular degeneration (nAMD) in the study eye. Color, fluorescein angiography (FA) and OCT images acquired at baseline and during the 2-year follow-up were graded systematically for presence of MA. Regression models were constructed to explore relationships between MA and lesion morphology and vision measures (best-corrected distance and near acuity, reading speed and index, contrast sensitivity). Primary outcome was development of intralesional MA (≥175 μm greatest linear dimension of choroidal vessels seen on FA and/or color, aided by OCT) lying within the maximum footprint of the neovascular lesion. Study eye data were available for 594 of 610 participants; 57 (9.6%) showed intralesional MA at baseline. Incident intralesional MA occurred in 24.4% by the final visit and extralesional MA in only 1.54%. In fellow eyes, an established nAMD lesion was present at baseline in 248 of whom 42 (16.9%) showed intralesional MA at baseline and 32 (12.9%) developed incident intralesional MA. The odds of incident intralesional MA by final visit were lower in study eyes that had ≥50% classic CNV at baseline (odds ratio [OR], 0.39; 95% confidence interval [CI], 0.19-0.80; P= 0.010), subretinal fluid at final visit (OR, 0.41; 95% CI, 0.25-0.76; P= 0.004), or pigment epithelial detachment at final visit (OR, 0.40; 95% CI, 0.21-0.74; P= 0.004). Secondary analyses of incident or progressed intralesional MA in study eyes supported these findings, with odds increasing if the fellow eye had baseline intralesional MA (OR, 2.43; 95% CI, 1.09-5.44; P= 0.030). No significant associations were observed between development of intralesional MA and any other morphologic or visual function measure. Macular atrophy frequently develops within an nAMD lesion in eyes receiving anti-VEGF therapy over 2 years. No associations between incident MA and drug or treatment frequency or visual function were detected, providing some reassurance to clinicians; however, the longer-term effects remain unknown.

Non-invasive evaluation of neurovascular coupling in the murine retina by dynamic retinal vessel analysis.

BackgroundImpairment of neurovascular coupling (NVC) was recently reported in the context of subarachnoid hemorrhage and may correlate with disease severity and outcome. However, previous techniques to evaluate NVC required invasive procedures. Retinal vessels may represent an alternative option for non-invasive assessment of NVC.MethodsA prototype of an adapted retinal vessel analyzer was used to assess retinal vessel diameter in mice. Dynamic vessel analysis (DVA) included an application of monochromatic flicker light impulses in predefined frequencies for evaluating NVC. All retinae were harvested after DVA and electroretinograms were performed.ResultsA total of 104 retinal scans were conducted in 21 male mice (90 scans). Quantitative arterial recordings were feasible only in a minority of animals, showing an emphasized reaction to flicker light impulses (8 mice; 14 scans). A characteristic venous response to flicker light, however, could observed in the majority of animals. Repeated measurements resulted in a significant decrease of baseline venous diameter (7 mice; 7 scans, p < 0.05). Ex-vivo electroretinograms, performed after in-vivo DVA, demonstrated a significant reduction of transretinal signaling in animals with repeated DVA (n = 6, p < 0.001).ConclusionsTo the best of our knowledge, this is the first non-invasive study assessing murine retinal vessel response to flicker light with characteristic changes in NVC. The imaging system can be used for basic research and enables the investigation of retinal vessel dimension and function in control mice and genetically modified animals.

THERAPY OF SKIN VASCULAR MALFORMATIONS USING COPPER VAPOR LASER AND PULSED DYE LASER

Aim. Comparison of effectiveness of the application of copper vapor laser (CVL) and pulsed dye laser (PDL) in clinical practice. Development of choice criteria of the more effective method of treatment.Materials and methods. The clinical data using CVL and PDL in the treatment of skin vascular malformations are presented. The treatment gave good results in removing of dysplastic skin vessels in 2 and 6 months. The treatment was not painful, and patients did not need general and local anesthesia. The results were presented concerning computer modeling of selective heating of vessels in tissue with CVL and PDL radiation. These results allowed to determine the depth of location and dimensions of vessels for selective and secure removing and the safe dosage ranges were found.Results. On the base of the calculated data, one could conclude that the mode of heating of dysplastic vessels with micropulse series of CVL is more safe and effective than the mode of powerful short pulses in the case of PDL.

Coupling of CFD and semiempirical methods for designing three-phase condensate separator: case study and experimental validation

This study presents an approach to determine the dimensions of three-phase separators. First, we designed different vessel configurations based on the fluid properties of an Iranian gas condensate field. We then used a comprehensive computational fluid dynamic (CFD) method for analyzing the three-phase separation phenomena. For simulation purposes, the combined volume of fluid–discrete particle method (DPM) approach was used. The discrete random walk (DRW) model was used to include the effect of arbitrary particle movement due to variations caused by turbulence. In addition, the comparison of experimental and simulated results was generated using different turbulence models, i.e., standard k–ε, standard k–ω, and Reynolds stress model. The results of numerical calculations in terms of fluid profiles, separation performance and DPM particle behavior were used to choose the optimum vessel configuration. No difference between the dimensions of the optimum vessel and the existing separator was found. Also, simulation data were compared with experimental data pertaining to a similar existing separator. A reasonable agreement between the results of numerical calculation and experimental data was observed. These results showed that the used CFD model is well capable of investigating the performance of a three-phase separator.

Characterization of Schizolobium parahyba (Vell.) S.F. Blake and Eucalyptus urophylla S.T. Blake juvenile wood in Brazilian Savanna soil

The need to understand variations of wood characteristics in alternative species that have fast growth and good quality for the consumer market has been increasinggiven the prominent technological development of wood.This study aimed to evaluate the wood basic density and the anatomical characteristics of Schizolobium parahyba and Eucalyptus urophylla 3-year old juvenile wood planted in savanna soil in a 3x3m spacing.Wood disks were cut in different longitudinal (base-top) and radial (pith-bark) positions from five trees per species to determine the wood’sbasic density and fiber and vessel dimensions. The Schizolobium parahyba wood presented (i) lower basic density, vessel size and vessel frequency, and (ii) higher wood fiber width and diameter than Eucalyptus urophylla. The average wood basic density was 0.27 g/cm³ for S. prahyba and 0.40 g/cm³ for E. urophylla wood.

Influence of general characteristics and the main dimensions of vessels on fuel and environmental efficiency

В работата е проведен статистически анализ на влиянието на големината, товарния капацитет, работната скорост и основните размери и коефициенти на формата върху разхода на гориво на различни типове кораби. Предложени са препоръки за оптимални решения.

How Do Reaction and Reactor Conditions Affect Photoinduced Electron/Energy Transfer Reversible Addition–Fragmentation Transfer Polymerization?

The impact of conditions was investigated on a model photoinduced electron/energy transfer reversible addition–fragmentation chain transfer (PET-RAFT) polymerization. Within the cylindrical geometries studied, with relatively small changes in path length, the impact of reaction vessel dimensions and dilution was relatively small on the polymerization kinetics and control of the polymerization. This suggests that PET-RAFT can be relatively insensitive to small changes in reactor geometry and reaction volume when cylindrical systems are used. The intensity of the photoreactor was a key factor in determining reaction rate, with an approximate 1/2 order scaling of the apparent rate with intensity. Reactant concentration ratios were also important, with an approximate 1/2 order of the apparent rate with the photocatalyst loading and an approximate −1/2 order scaling apparent polymerization rate coefficient with the RAFT agent concentration. However, there is a limit to rate increases with higher Ir catalyst lo...

One-year clinical outcomes and multislice computed tomography angiographic results following implantation of the NeoVas bioresorbable sirolimus-eluting scaffold in patients with single de novo coronary artery lesions.

Tremendous efforts have been made to establish the concept of vascular restoration therapy with a fully bioresorbable scaffold for coronary artery disease. With an improved scaffold design and technologies, the novel NeoVas scaffold has shown promising clinical performance at 6months follow-up. The aim of this study was to investigate the 1year clinical outcomes and multislice computed tomography (MSCT) angiographic results after implantation of the NeoVas scaffold in patients with single de novo coronary artery lesions. The NeoVas first-in-man study was a prospective, two-center, single-arm study enrolling 31 patients who were eligible for the treatment. The composite endpoint of target lesion failure (TLF)-defined as cardiac death, target vessel myocardial infarction, and clinically indicated target lesion revascularization (TLR)-was assessed. Of the 31 patients scheduled for 1year clinical follow-up, 29 patients received MSCT examinations. At 1year follow-up, there was only 1 (3.2%) TLF, attributed to 1 patient who suffered ischemia-driven TLR at 181 days postprocedure. No cardiac deaths or scaffold thrombosis were observed. MSCT analysis demonstrated excellent vessel patency, with a median in-scaffold lumen area of 10.6 mm2 (interquartile range [IQR]: 8.2-11.7 mm2 ) and a minimal lumen diameter of 2.7 mm (IQR: 2.4-3.0 mm). This study demonstrated the safety and efficacy of the NeoVas scaffold for patients with single de novo coronary artery lesions at 1year of follow-up. Noninvasive MSCT data confirmed vessel patency and the maintenance of vessel dimensions following implantation of the NeoVas bioresorbable sirolimus-eluting scaffold.

3D whole-brain vessel wall cardiovascular magnetic resonance imaging: a study on the reliability in the quantification of intracranial vessel dimensions

BackgroundOne of the potentially important applications of three-dimensional (3D) intracranial vessel wall (IVW) cardiovascular magnetic resonance (CMR) is to monitor disease progression and regression via quantitative measurement of IVW morphology during medical management or drug development. However, a prerequisite for this application is to validate that IVW morphologic measurements based on the modality are reliable. In this study we performed comprehensive reliability analysis for the recently proposed whole-brain IVW CMR technique.MethodsThirty-four healthy subjects and 10 patients with known intracranial atherosclerotic disease underwent repeat whole-brain IVW CMR scans. In 19 of the 34 subjects, two-dimensional (2D) turbo spin-echo (TSE) scan was performed to serve as a reference for the assessment of vessel dimensions. Lumen and wall volume, normalized wall index, mean and maximum wall thickness were measured in both 3D and 2D IVW CMR images. Scan-rescan, intra-observer, and inter-observer reproducibility of 3D IVW CMR in the quantification of IVW or plaque dimensions were respectively assessed in volunteers and patients as well as for different healthy subjectsub-groups (i.e. < 50 and ≥ 50 years). The agreement in vessel wall and lumen measurements between the 3D technique and the 2D TSE method was also investigated. In addition, the sample size required for future longitudinal clinical studies was calculated.ResultsThe intra-class correlation coefficient (ICC) and Bland-Altman plots indicated excellent reproducibility and inter-method agreement for all morphologic measurements (All ICCs > 0.75). In addition, all ICCs of patients were equal to or higher than that of healthy subjects except maximum wall thickness. In volunteers, all ICCs of the age group of ≥50 years were equal to or higher than that of the age group of < 50 years. Normalized wall index and mean and maximum wall thickness were significantly larger in the age group of ≥50 years. To detect 5% - 20% difference between placebo and treatment groups, normalized wall index requires the smallest sample size while lumen volume requires the highest sample size.ConclusionsWhole-brain 3D IVW CMR is a reliable imaging method for the quantification of intracranial vessel dimensions and could potentially be useful for monitoring plaque progression and regression.

Design of the Optional Forward Superconducting Di- pole Magnet for the FCC-hh Detector

A 4-T, 10-m free bore and 20-m long central solenoid is proposed as the main magnet in the baseline detector for the future circular collider (FCC) hadron–hadron collisions physics program. Besides the 4-T axial magnetic field around the interaction point in the center of the main solenoid, additionally, magnetic field is required in the forward directions. This provides sufficient bending power for particles traveling at small angles from the beam axis as well. Using forward solenoids is the baseline. Here, we present the option of using forward dipole magnets. A previously published design foresaw cone-shaped dipole magnets as well as force and torque balanced. This design, however, evolved to a more practical design, where the cryostat occupies the same space as in the baseline with forward solenoids, meaning that the vacuum vessel dimensions in solenoid and dipole designs are the same.

Fetal “Aortic Coarctation” and Different Neonatal Follow-Up in 3 Cases

Abstract Heart defects which includes narrowing of aortic isthmus - aortic coarctation (CoA) are one of the most prevalent birth defects. Making a correct prenatal diagnosis of CoA is very difficult and problematic. We are still observing many false (+) and false (-) diagnoses. In presenting 3 cases with prenatal suspicion of CoA only one patient confirmed this defect in the postnatal life. In the fetal echocardiography inappropriate dimensions of great vessels and PA/Ao ratio are very relevant in the CoA diagnostics. Based on such suspicion before delivery we can select a group in which birth in the tertiary center, prostin infusion, control ECHO examinations and planned cardiac surgery will be needed. But wide differential diagnosis including pulmonary dilatation (due to pulmonary hypertension or fetal blood redistribution due to possible infection) is required.

Vasoconstriction and Impairment of Neurovascular Coupling after Subarachnoid Hemorrhage: a Descriptive Analysis of Retinal Changes.

Impaired cerebral autoregulation and neurovascular coupling (NVC) contribute to delayed cerebral ischemia after subarachnoid hemorrhage (SAH). Retinal vessel analysis (RVA) allows non-invasive assessment of vessel dimension and NVC hereby demonstrating a predictive value in the context of various neurovascular diseases. Using RVA as a translational approach, we aimed to assess the retinal vessels in patients with SAH. RVA was performed prospectively in 24 patients with acute SAH (group A: day 5-14), in 11 patients 3months after ictus (group B: day 90±35), and in 35 age-matched healthy controls (group C). Data was acquired using a Retinal Vessel Analyzer (Imedos Systems UG, Jena) for examination of retinal vessel dimension and NVC using flicker-light excitation. Diameter of retinal vessels-central retinal arteriolar and venular equivalent-was significantly reduced in the acute phase (p<0.001) with gradual improvement in group B (p<0.05). Arterial NVC of group A was significantly impaired with diminished dilatation (p<0.001) and reduced area under the curve (p<0.01) when compared to group C. Group B showed persistent prolonged latency of arterial dilation (p<0.05). Venous NVC was significantly delayed after SAH compared to group C (A p<0.001; B p<0.05). To our knowledge, this is the first clinical study to document retinal vasoconstriction and impairment of NVC in patients with SAH. Using non-invasive RVA as a translational approach, characteristic patterns of compromise were detected for the arterial and venous compartment of the neurovascular unit in a time-dependent fashion. Recruitment will continue to facilitate a correlation analysis with clinical course and outcome.

Measuring blood oxygen saturation along a capillary vessel in human.

Measuring oxygen saturation in capillary vessels could provide valuable information on oxygen transport and tissue viability. Most spectroscopic measurement techniques, however, lack the spatial resolution to account for the small vessel dimensions within a scattering tissue and the steep gradients of oxygen saturation levels. Here, we developed a noninvasive technique for image-guided confocal measurement of the optical absorption spectrum from a small region that is comparable in size to the cross section of a single capillary vessel. A wide range of oxygen saturation levels were measured in a single capillary in a human volunteer, with blood deoxygenation rates of 7.1% per hundred microns. The technique could help in studying oxygen exchange dynamics in tissues and could play a key role in future clinical diagnosis and therapeutic applications that require localized functional tissue inspection.

Effect of Inaugurating the Third Set of Locks in the Panama Canal on Vessel Size, Manoeuvring and Lockage Time

The Panama Canal (PC) has recently been in the world spotlight. In August 2014, it celebrated 100 years of uninterrupted service and, in June 2016, the expansion project for the canal was inaugurated. The final project involved building a third set of locks. Once the canal started to operate, it could be seen that the way in which vessels transited the canal remained the same. However, the dimensions of locks and their revised operating procedures have had an effect on vessel size and the manoeuvres for the larger vessels. After the first transit on 26 June 2016, it was possible to have access to data on the new lockage systems for Neopanamax ships. The thorough statistical study of these new datasets (composed of Analysis of Variance (ANOVA), multivariate regression and statistical quality control techniques) has shown the main drivers of transit time across the Cocolí and Agua Clara locks. It has also made it possible to test the learning curve of Panama Canal pilots in the newly expanded canal. The effects of pilot training on the time it takes to transit through the locks, direction of entry in each lock, the type of vessel, vessel dimensions and the use of different types of manoeuvres have been analysed. The results are used to characterise and help optimise the performance of this new and unique lock system.

Ex Vivo Assessment of Coronary Atherosclerotic Plaque by Grating-Based Phase-Contrast Computed Tomography: Correlation With Optical Coherence Tomography.

The aim of this study was to determine the diagnostic accuracy of grating-based phase-contrast computed tomography (gb-PCCT) to classify and quantify coronary vessel characteristics in comparison with optical coherence tomography (OCT) and histopathology in an ex vivo setting. After excision from 5 heart specimens, 15 human coronary arteries underwent gb-PCCT examination using an experimental imaging setup consisting of a rotating molybdenum anode x-ray tube, a Talbot-Lau grating interferometer, and a single photon counting detector. Subsequently, all vessels were imaged by OCT and histopathologically processed. Optical coherence tomography, gb-PCCT, and histopathology images were manually matched using anatomical landmarks. Optical coherence tomography and gb-PCCT were reviewed by 2 independent observers blinded to histopathology. Vessel, lumen, and plaque area were measured, and plaque characteristics (lipid rich, calcified, and fibrous) were determined for each section. Measures of diagnostic accuracy were derived, applying histopathology as the standard of reference. Of a total of 286 assessed cross sections, 241 corresponding sections were included in the statistical analysis. Quantitative measures derived from gb-PCCT were significantly higher than from OCT (P < 0.001) and were strongly correlated with histopathology (Pearson r ≥0.85 for gb-PCCT and ≥0.61 for OCT, respectively). Results of Bland-Altman analysis demonstrated smaller mean differences between OCT and histopathology than for gb-PCCT and histopathology. Limits of agreement were narrower for gb-PCCT with regard to lumen area, for OCT with regard to plaque area, and were comparable with regard to vessel area. Based on histopathology, 228/241 (94.6%) sections were classified as fibrous, calcified, or lipid rich. The diagnostic accuracy of gb-PCCT was excellent for the detection of all plaque components (sensitivity, ≥0.95; specificity, ≥0.94), whereas the results for OCT showed sensitivities of ≥0.73 and specificities of ≥0.66. In this ex vivo setting, gb-PCCT provides excellent results in the assessment of coronary atherosclerotic plaque characteristics and vessel dimensions in comparison to OCT and histopathology. Thus, the technique may serve as adjunct nondestructive modality for advanced plaque characterization in an experimental setting.