Vessel Width Research Articles

Abstract MP02: Proprotein Convertase Subtilisin/kexin Type 6 (PCSK6) Is Involved In Regulation Of Vasculogenesis

Background: PCSK6 cleaves and activates growth factors involved in cell differentiation and Pcsk6-/- mice exhibit 25% embryonic lethality, while surviving offspring have blindness and cyclopia. We have shown that PCSK6 localizes to vascular smooth muscle cells of intra-plaque neovessels. Hypothesis: We hypothesize that a) the processes of vasculogenesis, atherosclerosis and plaque neovascularisation share common molecular regulators and b) that PCSK6 plays a common role in vascular remodeling. Methods: Association between SNPs near the PCSK6 gene and levels of 90 plasma proteins was tested using data from 30,931 individuals in the SCALLOP consortium. Data from the FinnGen consortium (Release 3) were queried to explore the PCSK6 SNPs associated with specific disease phenotypes. Morpholino technology was used for Pcsk6 knockdown in zebrafish, coupled with vascular phenotype studies. Pcsk6-/- mice were used to study the expression of vasculogenesis related genes as well as vascular morphology. Results: Rs7178801 and rs11639051 in the PCSK6 gene were found to relate to plasma PDGFB and VEGFD levels, while rs45482895 associated with diabetic retinopathy and disorders of the choroid and retina in humans. Gross phenotypic and histological examination of zebrafish embryos with ablated PCSK6 showed improper peripheral vascular patterning of intersegmental vessels, cerebral and myocardial haemorrhage, atrial dilatation and pericardial oedema. Gene expression levels of vasculogenesis related genes, i.e. Vegfa, Vegfb, Angpt1 and Tgfb2 were altered in the heart, liver and adipose tissue in Pcsk6-/- mice. In the retinas of Pcsk6-/- mice, Pdgfb was significantly downregulated compared to controls. Staining of the retinal vasculature showed that superficial retinal vasculature had a lower number of branching points and vessel width, while deep retinal vasculature covered a significantly smaller area in Pcsk6-/- Conclusions: Here, we show that variants in the PCSK6 gene associate with growth factors implicated in vasculogenesis and retinopathy. Lack of Pcsk6 in mice and zebrafish led to vascular patterning defects. Further studies will aim to elucidate the mechanisms by which PCSK6 regulates vasculogenesis in homeostatic and pathological conditions

Anatomical Properties and Utilization of 3-, 5-, and 7-yr-old Falcata [Falcataria moluccana (Miq.)] Barneby & J. W. Grimes] from Caraga Region, Mindanao Philippines

The anatomical properties – namely, fiber length, fiber diameter, lumen diameter, cell wall thickness, vessel length, and width – of young (3-, 5-, and 7-yr-old) Falcataria molucanna (Miq.) Barneby & J. W. Grimes from Caraga Region, Philippines were evaluated to determine the variations among ages between and among trees, tree height, and their derived values as well, henceforth as a basis in recommending the potential of the species for various enduses. Three trees per age of known seed origin were collected and used as materials. FPRDI standard procedures for determining anatomical properties were followed. Data were analyzed using three-factorial in complete randomized design (CRD) and Tukey’s honestly significant difference (HSD) test was used to determine significant differences among treatment means. Except for cell wall thickness, the variations in anatomical properties among age and tree were highly significant but not significant among height levels. Fiber diameter and lumen diameter increased as the trees aged. The cell wall was very thin with mean values of 0.0033 mm (3-yr-old), 0.0032 mm (5-yr-old), and 0.0031 mm (7-yr-old). Vessel length and width decreased from 3- to 5-yr-old and increased at 7-yr-old. Fiber length’s mean values increased from near pith (NP), middle (M), to near bark (NB) at all three ages and height levels except in the 3-yr middle (1.1665, 1.2032, and 1.1541 mm) and 7-yr butt (1.1541, 1.2326, and 1.2009 mm). Other anatomical properties at three ages showed no consistent trend of variations from NP to NB. The potential uses of younger falcata based on their anatomical properties were for pulp and paper, veneer, and light construction applications where strength and durability are not important.

Simulation of the process of angiogenesis: Quantification and assessment of vascular patterning in the chicken chorioallantoic membrane

Angiogenesis, the formation of new blood vessels from pre-existing ones, begins during embryonic development and continues throughout life. Sprouting angiogenesis is a well-defined process, being mainly influenced by vascular endothelial growth factor (VEGF). In this study, we propose a meshless-based model capable of mimicking the angiogenic response to several VEGF concentrations. In this model, endothelial cells migrate according to a diffusion-reaction equation, following the VEGF gradient concentration. The chick chorioallantoic membrane (CAM) assay was used to model the branching process and to validate the obtained numerical results. To analyse the angiogenic response, the total vessel number and the total vessel length presented in the CAM images and in the simulations for all the VEGF concentrations tested were quantified. In both the CAM assay and simulation, the treatments with VEGF increased the total vessel number and the total vessel length. The obtained quantitative results were very similar between the two methodologies used. The proposed model accurately simulates the capillary network pattern concerning its structure and morphology, for the lowest VEGF concentration tested. For the highest VEGF concentration, the capillary network predicted by the model was less accurate when compared to the one presented in the CAM assay but this may be explained by changes in blood vessel width at higher VEGF concentrations. This remains to be tested.

Concurrent OCT and OCT angiography of retinal neurovascular degeneration in the 5XFAD Alzheimer's disease mice.

.Significance: As one part of the central nervous system, the retina manifests neurovascular defects in Alzheimer’s disease (AD). Quantitative imaging of retinal neurovascular abnormalities may promise a new method for early diagnosis and treatment assessment of AD. Previous imaging studies of transgenic AD mouse models have been limited to the central part of the retina. Given that the pathological hallmarks of AD frequently appear in different peripheral quadrants, a comprehensive regional investigation is needed for a better understanding of the retinal degeneration associated with AD-like pathology.Aim: We aim to demonstrate concurrent optical coherence tomography (OCT) and OCT angiography (OCTA) of retinal neuronal and vascular abnormalities in the 5XFAD mouse model and to investigate region-specific retinal degeneration.Approach: A custom-built OCT system was used for retinal imaging. Retinal thickness, vessel width, and vessel density were quantitatively measured. The artery and vein (AV) were classified for differential AV analysis, and trilaminar vascular plexuses were segmented for depth-resolved density measurement.Results: It was observed that inner and outer retinal thicknesses were explicitly reduced in the dorsal and temporal quadrants, respectively, in 5XFAD mice. A significant arterial narrowing in 5XFAD mice was also observed. Moreover, overall capillary density consistently showed a decreasing trend in 5XFAD mice, but regional specificity was not identified.Conclusions: Quadrant- and layer-specific neurovascular degeneration was observed in 5XFAD mice. Concurrent OCT and OCTA promise a noninvasive method for quantitative monitoring of AD progression and treatment assessment.

Image processing pipeline for the detection of blood flow through retinal vessels with subpixel accuracy in fundus images

Background and ObjectiveBlood flow detection through the retinal vessels is an essential step in diagnosing several eye diseases. It manifests itself as changes in vessel diameter in consecutive phases of blood flow. Previous studies focused mainly on determining retinal vessel diameter by the manual demarcation of vessel edges, which is time-consuming. As a result, only a few selected vessels were considered, which is not reliable. Such measurements are also prone to human errors and operator subjectivity, which additionally decreases their reliability. For these reasons, this paper proposes an automated pipeline to analyze the blood flow through retinal vessels. MethodsConvolutional neural networks were used for optic disc and vessel detection and full width at half maximum analysis used for vessel width assessment at the subpixel level. Measurements of the diameter were performed for five phases of the blood flow to all vessels at a particular distance derived from the optic disc size. We tested the approach on fundus images of five patients, with both eyes examined in each participant. The threshold for the detections of blood flow was when the retinal diameter vessel measurements were above the camera's resolution as compared among all 5 phases of blood flow. ResultsA total of 205 large caliber blood vessels were analyzed with blood flow detected in 18 retinal blood vessels. Conclusions Average vessel diameters derived from manual and automatic measurements differed on average by 4.96%. Average relative errors for single vessel measurements along the vessels range from 4.21 to 11.85%, with a global average at the level of 8%. Therefore, the measurements can be considered as accurate and in a high agreement between the expert and algorithm

Image segmentation for neuroscience: lymphatics

A recent discovery in neuroscience prompts the need for innovation in image analysis. Neuroscientists have discovered the existence of meningeal lymphatic vessels in the brain and have shown their importance in preventing cognitive decline in mouse models of Alzheimer’s disease. With age, lymphatic vessels narrow and poorly drain cerebrospinal fluid, leading to plaque accumulation, a marker for Alzheimer’s disease. The detection of vessel boundaries and width are performed by hand in current practice and thereby suffer from high error rates and potential observer bias. The existing vessel segmentation methods are dependent on user-defined initialization, which is time-consuming and difficult to achieve in practice due to high amounts of background clutter and noise. This work proposes a level set segmentation method featuring hierarchical matting, LyMPhi, to predetermine foreground and background regions. The level set force field is modulated by the foreground information computed by matting, while also constraining the segmentation contour to be smooth. Segmentation output from this method has a higher overall Dice coefficient and boundary F1-score compared to that of competing algorithms. The algorithms are tested on real and synthetic data generated by our novel shape deformation based approach. LyMPhi is also shown to be more stable under different initial conditions as compared to existing level set segmentation methods. Finally, statistical analysis on manual segmentation is performed to prove the variation and disagreement between three annotators.

ANATOMICAL RADIAL VARIATION AND DENSITY IN WOOD OF RUBBER TREE [Hevea brasiliensis (Willd. ex A. Juss.) Muell. Arg.] CLONES

The anatomical structure and physical properties of wood change signifcantly among trees of the same species and even among different parts of the same tree. However, studies that characterize radial variation of anatomical characteristics and wood density among clones are scarce, specifcally for the rubber tree [Hevea brasiliensis (Will. ex Adr. De Juss.) Muell]. Thus, the objective of the research was evaluating the anatomical radial variation and density in wood of Hevea brasiliensis clones. For this study, 30 trees, three of each progeny from 10 clones were used. For most clones, we noticed an increase in fber length and vessel diameter towards the bark. For vessel frequency, ray height, width and frequency, we observed a decrease towards the bark. Fiber wall thickness was the most distinctive anatomical characteristic, compared to the others, presenting a trend of thicker walls in the middle position, consequently infuencing basic density clones.

A Method of Blood Vessel Segmentation in Fundus Images Based on Image Enhancement

The changes of retinal vessel width are the key steps in the accurate diagnosis, early treatment and surgical planning of ocular diseases. The segmentation of retinal vessel is the basis of computer-aided diagnosis and large-scale disease screening. In this paper, we propose an algorithm for segmentation of fundus image based on image enhancement. At first, the ocular fundus image is enhanced by Laplacian pyramid, and the enhanced image vessel is more obvious than the background. Then, an improved matching filter algorithm is used to segment the ocular fundus image vessel. Experimental results show that the proposed method is more accurate than the traditional segmentation method. And it has strong robustness to the fundus images under different illumination conditions.

Will climate change shift carbon allocation and stem hydraulics? Insights on a systemic view of carbon- and water-related wood traits in an anysohydric tropical tree species (Hymenaea courbaril, Leguminosae)

Tropical forests uptake more atmospheric CO2 and transpire more water than any other forest in the world and are critical components of the global carbon and hydrological cycles. Both cycles depend to a great extent on the carbon and water balance of individual trees. Such adjustments are usually evaluated through well-established and newly-emerging traits but integrating them for a systemic understanding of trees' responses to climate change can be challenging. We propose using complex correlation networks to integrate and understand how trees coordinate water- and carbon-related traits under changing climate conditions. We built a correlation network based on 20 traits measured in the wood of Hymenaea courbaril (Leguminosae) trees, a species known for its extreme anisohydric water-use strategy, sampled along a climate gradient in Southeastern Brazil. Intercellular to ambient CO2 concentrations ratio (ci/ca, estimated from tree-ring δ13C) is a central network trait for being coordinated with several hydraulic and carbon allocation traits. Trees of H. courbaril coordinate these traits along the climate gradient, favoring high ci/ca under warm and dry conditions. A high ci/ca is only possible through a consistent water supply provided by wider vessels together with the investment on soluble sugars, at the detriment of starch, likely for hydraulic maintenance. Trees also favor heat resistance by investing in cell-wall xylose, another central network trait, from xyloglucans and xylans, at the expense of mannose from glucomannans. Such trade-offs within, and between, structural and non-structural carbon allocation reflect well-known metabolic pathways in plants. In summary, this systemic approach confirms previously reported patterns on leaf physiology, stem hydraulics and carbon adjustments while bringing to light the previously unreported role of cell-wall composition and its fine adjustments to cope with climate change.

Caffeine Inhibits Direct and Indirect Angiogenesis in Zebrafish Embryos.

In this study, we report the effects of caffeine on angiogenesis in zebrafish embryos both during normal development and after exposure to Fibroblast Growth Factor 2 (FGF2). As markers of angiogenesis, we measured the length and width of intersegmental vessels (ISVs), performed whole-mount in situ hybridization with fli1 and cadh5 vascular markers, and counted the number of interconnecting vessels (ICVs) in sub-intestinal venous plexus (SIVP). In addition, we measured angiogenesis after performing zebrafish yolk membrane (ZFYM) assay with microinjection of fibroblast growth factor 2 (FGF2) and perivitelline tumor xenograft assay with microinjection of tumorigenic FGF2-overexpressing endothelial (FGF2-T-MAE) cells. The results showed that caffeine treatment causes a shortening and thinning of ISVs along with a decreased expression of the vascular marker genes and a decrease in the number of ICVs in the SIVP. Caffeine was also able to block angiogenesis induced by exogenous FGF2 or FGF2-producing cells. Overall, our results are suggestive of the inhibitory effect of caffeine in both direct and indirect angiogenesis.

Ficoxylon fusiforme (Moraceae), a New Species from the Upper Cretaceous Nubian Sandstone, Southern Egypt

A new species of Ficoxylon Kaiser (Moraceae) is described from the Upper Cretaceous Nubian Sandstone, Aswan area, southern Egypt. The new species, Ficoxylon fusiforme, is the third report of a Cretaceous wood attributed to Ficoxylon worldwide. The two other Cretaceous records, F. cretaceum Schenk and ?F. sp. of Krausel, are also from Egypt. Ficoxylon species are common in the Tertiary, from the Palaeocene to the Pliocene. An emended generic diagnosis is proposed for Ficoxylon, which was erected in 1880 with few details. The new species is compared with the 18 currently recognized species of Ficoxylon/Ficus; it is distinguished by a combination of characters: predominantly solitary, few, relatively wide vessels; axial parenchyma bands 3–8 cells wide; 2–7 seriate, spindle-shaped, closely spaced, and slightly heterocellular rays; thin-walled, nonseptate fibers. Comments are made on the Egyptian fossil remains of Moraceae and on all Egyptian Cretaceous wood taxa reported to date. Preliminary biogeographic and climatic implications are given.

Development of successive cambia and structure of secondary xylem in the stems and roots of Distimake tuberosus (Convolvulaceae)

In the present study, development of trilobed stem is investigated in Distimake tuberosus (Convolvulaceae) by histological methods. Increase in stem thickness and formation of trilobed stem was achieved by forming crescent shaped successive cambial segments from the pericyclic parenchyma at three equidistant sites. In contrast, the alternate segments of the vascular cambium were functionally less active, dividing leisurely (referred henceforth as functionally less active cambium) and did not form the successive cambium. The newly formed cambial segments divide bi-directionally and produced its derivatives, while functionally less active segment lagged behind. The secondary xylem formed from the functionally less active cambial segments have unique pattern of vessels distribution i.e., wide vessels rare or completely absent. Parenchyma (both, axial and ray) proliferation, formation of ray cambium, functionally inverse cambia, tyloses in fibriform vessels and the occurrence of bordered pits in xylem ray cells are observed in all samples. Root diameter increased by developing concentric rings of successive cambia and maintained a circular outline. Formation of successive cambia on three sides and alteration in stem outline may be associated with protection of conducting elements against stem torsion and internal injury. Formation of conducting elements from the ray cambium and internal cambium suggest rapid and safe conduction of photosynthate, water and mineral elements.

Retinal oximetry with a prototype handheld oximeter during hyperoxia.

PurposeRetinal oximetry measures oxygen saturation in retinal vessels. With the introduction of a mobile handheld prototype oximeter, this technique will become available for a broader patient population including bedridden patients and newborn babies. The objective is to determine the sensitivity of this handheld oximeter in room air and during isocapnic hyperoxia. A comparison is made between the handheld oximeter and the Oxymap T1.MethodsThirteen young healthy subjects with a mean age of 25 ± 2 years were recruited at the Leiden University Medical Center. Retinal oximetry images were acquired during normoxia and during isocapnic hyperoxia for both the prototype oximeter and the OxymapT1. Isocapnic hyperoxia was induced with the dynamic end‐tidal forcing technique. For both oximeters, the oxygen saturation and vessel width were measured with Oxymap Analyzer software. The hyperoxic state was verified with blood gas analysis.ResultsThe mean oxygen saturation measured with the handheld oximeter in arterioles was 91.3% ± 3.9% during normoxia and 94.6% ± 3.9% during hyperoxia (p = 0.001). Oxygen saturation in venules was 56.3% ± 9.8% during normoxia and 82.2 ± 7.4% during hyperoxia (p < 0.001). For the Oxymap T1, the mean oxygen saturation for arterioles was 94.0% ± 2.6% during normoxia and 95.4%±3.2% during hyperoxia (p = 0.004). For the venules, the oxygen saturation was during normoxia 58.9%±3.2% and 84.3 ± 4.0% during hyperoxia (p < 0.001).ConclusionThe handheld retinal oximeter is sensitive to the changes in inhaled oxygen concentration. A small increase in oxygen saturation was measured in the arterioles and a larger increase in the venules. The handheld oximeter gives similar values as the ‘gold standard’ Oxymap T1 oximeter.

On the quantitative effects of compression of retinal fundus images on morphometric vascular measurements in VAMPIRE

Background and Objectives: This paper reports a quantitative analysis of the effects of joint photographic experts group (JPEG) image compression of retinal fundus camera images on automatic vessel segmentation and on morphometric vascular measurements derived from it, including vessel width, tortuosity and fractal dimension.Methods: Measurements are computed with vascular assessment and measurement platform for images of the retina (VAMPIRE), a specialized software application adopted in many international studies on retinal biomarkers. For reproducibility, we use three public archives of fundus images (digital retinal images for vessel extraction (DRIVE), automated retinal image analyzer (ARIA), high-resolution fundus (HRF)). We generate compressed versions of original images in a range of representative levels.Results: We compare the resulting vessel segmentations with ground truth maps and morphological measurements of the vascular network with those obtained from the original (uncompressed) images. We assess the segmentation quality with sensitivity, specificity, accuracy, area under the curve and Dice coefficient. We assess the agreement between VAMPIRE measurements from compressed and uncompressed images with correlation, intra-class correlation and Bland-Altman analysis.Conclusions: Results suggest that VAMPIRE width-related measurements (central retinal artery equivalent (CRAE), central retinal vein equivalent (CRVE), arteriolar-venular width ratio (AVR)), the fractal dimension (FD) and arteriolar tortuosity have excellent agreement with those from the original images, remaining substantially stable even for strong loss of quality (20% of the original), suggesting the suitability of VAMPIRE in association studies with compressed images.

Retinal venular tortuosity and fractal dimension predict incident retinopathy in adults with type 2 diabetes: the Edinburgh Type 2 Diabetes Study

Aims/hypothesisOur aim was to determine whether a range of prespecified retinal vessel traits were associated with incident diabetic retinopathy in adults with type 2 diabetes.MethodsIn the prospective observational cohort Edinburgh Type 2 Diabetes Study of 1066 adults with type 2 diabetes, aged 60–75 years at recruitment, 718 were free from diabetic retinopathy at baseline. Baseline retinal traits including vessel widths, tortuosity (curvature) and fractal dimensions (network complexity), were quantified using fundus camera images and semiautomated software, and analysed using logistic regression for their association with incident diabetic retinopathy over 10 years.ResultsThe incidence of diabetic retinopathy was 11.4% (n = 82) over 10 years. After adjustment for a range of vascular and diabetes-related risk factors, both increased venular tortuosity (OR 1.51; 95% CI 1.15, 1.98; p = 0.003) and decreased fractal dimension (OR 0.75; 95% CI 0.58, 0.96; p = 0.025) were associated with incident retinopathy. There was no evidence of an association with arterial tortuosity, and associations between measurements of vessel widths and retinopathy lost statistical significance after adjustment for diabetes-related factors and vascular disease. Adding venular tortuosity to a model including established risk factors for diabetic retinopathy (HbA1c, BP and kidney function) improved the discriminative ability (C statistic increased from 0.624 to 0.640, p = 0.013), but no such benefit was found with fractal dimension.Conclusions/interpretationIncreased retinal venular tortuosity and decreased fractal dimension are associated with incident diabetic retinopathy, independent of classical risk factors. There is some evidence that venular tortuosity may be a useful biomarker to improve the predictive ability of models based on established retinopathy risk factors, and its inclusion in further risk prediction modelling is warranted.Graphical abstract

Denser Retinal Microvascular Network Is Inversely Associated With Behavioral Outcomes and Sustained Attention in Children

Changes in geometry of the retinal microvascular network, including vessel width, vessel density, and tortuosity, have been associated with neurological disorders in adults. We investigated metrics of the retinal microvasculature in association with behavior and cognition in 8- to 12-year-old children. Digital fundus images of 190 children (48.2% girls, mean age 9.9 years) were used to calculate retinal vessel diameters, fractal dimension, lacunarity, and tortuosity. Parents filled out a Strengths and Difficulties Questionnaire (SDQ) for behavioral screening. Cognitive performance testing included a computerized version of the Stroop test (selective attention), the Continuous Performance (sustained attention), the Digit-Symbol (visual scanning and information-processing speed) and the Pattern Comparison (visuospatial analytic ability) tests from the Neurobehavioral Evaluation System (NES3) battery. Retinal vessel geometry was significantly associated with the SDQ problem score, which increased with 1.1 points (95% CI: 0.3 to 1.9 points) per interquartile (IQR) increment in retinal fractal dimension, and decreased 1.4 points (95% CI: −2.4 to −0.4 points) or decreased 1.0 points (95% CI: −2.1 to 0.1 points) per IQR increment in retinal vascular lacunarity or tortuosity, respectively. Sensitivity analyses showed that results were driven by the hyperactivity/inattention and conduct problem scales of the SDQ. Correspondingly, mean reaction time on the Continuous Performance test increased by 11 ms (95% CI: 4.4 to 17.6 ms) with an IQR increase in fractal dimension. The results indicate that a denser retinal microvascular network, exemplified by a higher fractal dimension and lower lacunarity, are inversely associated with behavioral outcomes and sustained attention in children.

An optimized segmentation and quantification approach in microvascular imaging for OCTA-based neovascular regression monitoring

BackgroundQuantification of neovascularization changes in terms of neovascular complex (NVC) acquired from the optical coherence tomography angiography (OCTA) imaging is extremely important for diagnosis and treatment monitoring of proliferative diabetic retinopathy (PDR). However, only few vessel extraction methods have so far been reported to quantify neovascular changes in NVC with proliferative diabetic retinopathy PDR based on OCTA images.MethodsHere we propose an optimized approach to segment blood vessels, which is based on an improved vascular connectivity analysis (VCA) algorithm and combined with morphological characterization and elimination of noise and artifacts. The length and width of vessels are obtained in the quantitative assessment of microvascular network. The feasibility of the proposed method is further studied by a treatment monitoring and statistical analysis process, as we have monitored and statistically analyzed the changes of NVC based on sampled OCTA images of PDR patients (N = 14) after treatment by intravitreal injection of conbercept.ResultsThe proposed method has demonstrated better performance in accuracy compared with existing algorithms and can thus be used for PRD treatment monitoring. Following the PDR treatment monitoring study, our data has shown that from the 1st day to 7th day of treatment, the averaged (arithmetic mean) length of NVC has been substantially shortened by 36.8% (P < 0.01), indicating significant effects of treatment. Meanwhile, the averaged (arithmetic mean) width of NVC from the 1st day to 7th day of treatment has been increased by 10.2% (P < 0.05), indicating that most of the narrow neovascularization has been reduced.ConclusionThe results and analysis have confirmed that the proposed optimization process by the improved VCA method is both effective and feasible to segment and quantify the NVC with lower noise and fewer artifacts. Thus, it can be potentially applied to monitor the fibrovascular regression during the treatment period.Clinical Trial Registration This trial is registered with the Chinese Clinical Trial Registry (Registered 27 December 2017, http://www.chictr.org.cn, registration number ChiCTR-IPR-17014160).

Retinal vascular caliber in turkish adolescents with type 1 diabetes mellitus

Diabetic retinopathy (DR) is a common result of diabetes mellitus (DM). Alterations in retinal vascular caliber may be early finding of diabetic retinopathy. The aim of this study is to demonstrate retinal vascular caliber changes in Turkish adolescents with type 1 diabetes mellitus (T1D). This prospective and cross-sectional study included 108 eyes of the T1D adolescents and 75 eyes of the age-sex matched control group. Fundus images of the both groups were taken with fundus camera system (FA; Visucam500; Carl Zeiss Meditec, Jena, Germany) and were analyzed with IVAN which is a semi-automated system used to measure the width of retinal vessels using a digital retinal image (Nicole J. Ferrier, College of Engineering, Fundus Photography Reading Center, University of Wisconsin, Madison, WI, USA). Central retinal artery equivalent (CRAE), central retinal vein equivalent (CRVE) and artery-vein ratio (AVR) were compared between groups. Both groups were comparable in baseline characteristics (p>0.05). The mean CRAE value was higher in T1D group (179.03±29.58 µ in T1D group and 166.64±15.76 µ in control group, p

Linking root and stem hydraulic traits to leaf physiological parameters in Coffea canephora clones with contrasting drought tolerance

Knowing the key hydraulic traits of different genotypes at early seedling stages can potentially provide crucial information and save time for breeding programs. In the current study we investigated: (1) how root, stem and whole plant conductivities are linked to xylem traits, and (2) how the integrated hydraulic system impacts leaf water potential, gas exchange, chlorophyll a fluorescence and the growth of three coffee cultivars (clones of Coffea canephora Pierre ex Froehner cv. Conilon) with known differences in drought tolerance. The Conilon clones CL 14, CL 5 V and CL 109A, classified as tolerant, moderately tolerant, and sensitive to drought respectively, were grown under non-limiting soil-water supply but high atmospheric demand (i.e., high VPDair). CL 14 and CL 5 V displayed higher root and stem hydraulic conductance and conductivity, and higher whole plant conductivity than CL 109A, and these differences were associated with higher root growth traits. In addition, CL 109A exhibited a non-significant trend towards wider vessels. Collectively, these responses likely contributed to reduce leaf water potential in CL 109A, and in turn, reduced leaf gas exchange, especially during elevated VPDair. Even when grown under well-watered conditions, the elevated VPDair observed during this study resulted in key differences in the hydraulic traits between the cultivars corresponding to differences in plant water status, gas exchange, and photochemical activity. Together these results suggest that coffee hydraulic traits, even when grown under non-water stress conditions, can be considered in breeding programs targeting more productive and efficient genotypes under drought and high atmospheric demand.

Investigation of single bubble behavior under rolling motions using multiphase MPS method on GPU

Study of single bubble behavior under rolling motions can prove useful for fundamental understanding of flow field inside the modern small modular nuclear reactors. The objective of the present study is to simulate the influence of rolling conditions on single rising bubble in a liquid using multiphase Moving Particle Semi-implicit (MPS) method. Rolling force term was added to 2D Navier-Stokes equations and a computer program was written using C language employing OpenACC to port the code to GPU. Computational results obtained were found to be in good agreement with the results available in literature. The impact of rolling parameters on trajectory and velocity of the rising bubble has been studied. It has been found that bubble rise velocity increases with rolling amplitude due to modification of flow field around the bubble. It has also been concluded that the oscillations of free surface, caused by rolling, influence the bubble trajectory. Furthermore, it has been discovered that smaller vessel width reduces the impact of rolling motions on the rising bubble. The effect of liquid viscosity on bubble rising under rolling was also investigated and it was found that effects of rolling became more pronounced with the increase of liquid viscosity.