Vessel Area Research Articles

Optical coherence tomography reveals heterogeneity of the brain tissue and vasculature in the ischemic region after photothrombotic stroke in mice

We demonstrate in vivo imaging of the ischemic area in the mouse brain after photostroke using a custom prototype Gaussian‑beam optical coherence tomography (OCT) setup in which the near infrared imaging beam and the green photoinducing light pass through the same objective lens. The goal of our research was analysis of vascularity of the ischemic area during 2‑week progress of stroke and correlating the hypo‑ and hyperreflective OCT scattering areas with the location of activated microglia and astroglia. Angiogenesis, which was assessed using angiomaps, showed that the area of vessels in the ischemic center increased until day 7. OCT imaging revealed a heterogeneous scattering signal pattern in the ischemic area. On structural OCT images, we found presence of a core area of ischemia with a hyporeflective OCT signal and a halo of hyperreflective signal around the core. The core signal decreased in size by 70% by day 14. Immunocytochemistry revealed that the hyporeflective area in the ischemic core was associated with microglia/macrophage activation, whereas the hyperreflective signal from the halo came from activated astrocytes.

NDP-related retinopathies: clinical phenotype of female carriers

Background/aimsNorrin cysteine knot growth factor (NDP) located on the X chromosome, was previously reported to cause Norrie disease and familial exudative vitreoretinopathy (FEVR), which are blindness-causing ocular disorders, in males....

Optical coherence tomography angiography in the evaluation of vascular patterns of ocular surface squamous neoplasia during topical medical treatment

PurposeOptical coherence tomography angiography (OCTA) was utilized to examine changes in ocular surface squamous neoplasia (OSSN) vascular patterns over time in individuals treated with topical medical therapy. MethodsTen individuals with OSSN diagnosed by clinical examination and high resolution (HR)-optical coherence tomography (OCT) were recruited. All individuals received topical immuno- or chemotherapy. OCTA images were obtained and analyzed at three points: presentation, mid-treatment and tumor resolution. Tumor metrics including tumor area (TA), tumor volume (TV), tumor depth (TD), and total tumor density (TTD) were calculated. Vessel area density (VAD) was also quantified within the OSSN, the subepithelium under and adjacent to the OSSN and the subepithelium of the uninvolved, contralateral eye. Vascular network changes were also subjectively evaluated. ResultsTA, TV, TD and TTD all significantly decreased with time (p < 0.001). The mean VAD within the OSSN significantly decreased (p < 0.001) between visits (presentation: 26.52 ± 6.8%, mid-treatment: 7.19 ± 5.88%, tumor resolution: 0.11 ± 0.34%). The mean subepithelial VAD under the OSSN also decreased with time (23.22 ± 11.03%, 20.99 ± 5.99% and 19.58 ± 7.08%), and after resolution the sub-tumor VAD (19.58 ± 7.08%) was comparable to the subepithelial VAD in the contralateral eye (15.47 ± 4.37%, p > 0.05). The mean VAD in the subepithelium adjacent to the OSSN increased with treatment, then decreased significantly between mid-treatment and resolution (23.26 ± 4.54, 28.30 ± 7.43% and 21.68 ± 6.10%, p = 0.009). Qualitatively, the tumor subepithelial vascular network was complex and dense but with tumor resolution appeared less tortuous and similar to the uninvolved eye. ConclusionOCTA provided insight into the pathophysiology of tumor angiogenesis, showing decreased vascular density and normalization of vascular networks associated with tumor resolution.

Daily or Less Frequent Topical 1% Atropine Slows Defocus-Induced Myopia Progression in Contact Lens-Wearing Guinea Pigs

PurposeThis study compared the efficacy of topical 1% atropine applied daily versus every 3 days for controlling myopia progression in guinea pigs.MethodsTo induce myopia, pigmented guinea pigs (New Zealand strain, n = 38) wore monocular −10 D rigid gas-permeable (RGP) contact lenses, which were replaced after 3 weeks with −15 diopter (D) contact lenses. Animals were treated with 1% atropine either daily (Atr-QD; n = 12), or every 3 days (Atr-Q3D; n = 11), or with artificial tears (control group; n = 15). Spherical equivalent refractive error (SER) and axial length (AL) data, as well as retinal and choroidal thickness data were collected weekly.ResultsWhereas mean (±SEM) interocular differences (treated - fellow) in both SER and AL at week 0 (baseline) were similar for all groups, significant differences between the atropine-treated and control groups were evident by week 6 (SER and AL, P < 0.001). The treated eyes of the control group showed relatively more axial elongation and myopia progression than both the Atr-QD and Atr-Q3D groups. Choroidal blood vessel area also decreased over time in the treated eyes of the control group, coupled with choroidal thinning overall, with these changes being attenuated by atropine. Retinal thickness showed a developmental decrease over the treatment period but was unaffected by atropine.ConclusionsFor this defocus-induced guinea pig model of myopia, application of 1% topical atropine slows myopia progression, even when applied every 3 days.Translational RelevanceThe results from this study suggest that the frequency of dosing for topical atropine may be reduced from the widely used daily dosing regimen without loss of myopia control efficacy.

Changes in ocular blood flow and retinal oxygen metabolism during immunosuppressive therapy for initial-onset acute uveitis associated with Vogt-Koyanagi-Harada disease.

Purpose The aim of this study was to investigate the correlations between visual acuity, blood flow velocity in the choroid and optic nerve head (ONH) and oxygen saturation and calibre of retinal vessels during immunosuppressive therapy in patients with initial-onset acute uveitis associated with Vogt–Koyanagi–Harada (VKH) disease. Methods In this prospective study, 20 patients were studied. Laser speckle flowgraphy (LSFG) and retinal oximetry measurements were performed at baseline and at 4, 8 and 12 weeks after treatment. Results After immunosuppressive therapy, best-corrected visual acuity (BCVA) improved significantly at each post-treatment time-point compared with baseline value. Mean blur rate (MBR), representing blood flow velocity, in the choroid and ONH (overall and vessel areas) significantly increased. On the contrary, oxygen saturation of retinal arterioles and venules and calibre of retinal venules significantly decreased. There were significant negative correlations between ONH MBR vessel and arteriovenous oxygen saturation difference at baseline and at 4 weeks after treatment and between MBR tissue of the ONH and arteriovenous oxygen saturation difference at week 12 after treatment. Conclusions Immunosuppressive therapy in patients with initial-onset acute uveitis associated with VKH disease is associated with improved blood flow velocity in choroid and ONH and normalization of retinal oxygen metabolism and calibre of retinal venules. These correspond with improved visual acuity. These findings help explain the pathophysiology of VKH disease and its treatment and may provide biomarkers for choroiditis activity and response to treatment.

Differences in wood anatomy and chemistry of a Eucalyptus urophylla clone explained by site climate conditions

Environmental conditions can change both the quantity and quality of wood formation. This study aimed to evaluate anatomical and chemical changes in the wood of a Eucalyptus urophylla S.T. Blake clone cultivated in four sites of wide climatic conditions in Brazil. Radial samples were used to evaluate xylem anatomy along the growth cycles. Samples with a quarter of a disk were used to perform chemical analyses of extractives, total lignin (LG), syringyl/guaiacyl (S/G), holocellulose, and elemental analysis of wood. The elements Na, K, Ca, Mg, P, Mn, Fe, Zn, Ni, Cu, Cr, Cd, F, and Cl were also quantified. Correlations using the mean values of the variables per site were higher than those using values per tree growth cycle (years). Mean annual air temperature showed the highest correlations with wood density (r = −0.89) and the anatomical characteristics (vessel area: r = −0.68; fiber wall thickness: r = −0.70; vessel frequency: r = 0.74; and fiber lumen diameter: r = 0.90). Only LG and S/G showed significant correlations with the meteorological variables, with drier sites presenting a higher S/G. The anatomical characteristics change with regionwide climate features, while wood chemical characteristics showed weaker relations with climatic variations.

Blood Vessel Detection Algorithm for Tissue Engineering and Quantitative Histology

Immunohistochemistry for vascular network analysis plays a fundamental role in basic science, translational research and clinical practice. However, identifying vascularization in histological tissue images is time consuming and markedly depends on the operator’s experience. In this study, we present “blood vessel detection—BVD”, an automatic algorithm for quantitative analysis of blood vessels in immunohistochemical images. BVD is based on extraction and analysis of low-level image features and spatial filtering techniques, which do not require a training phase. BVD algorithm performance was comparatively evaluated on histological sections from three different in vivo experiments. Collectively, 173 independent images were analyzed, and the algorithm's results were compared to those obtained by human operators. The developed BVD algorithm proved to be a robust and versatile tool, being able to quantify number, area, and spatial distribution of blood vessels within all three considered histologic datasets. BVD is provided as an open-source application working on different operating systems. BVD is supported by a user-friendly graphical interface designed to facilitate large-scale analysis.

Intraocular Cytokine Changes in Patients with Polypoidal Choroidal Vasculopathy Treated with Ranibizumab

Purpose: To investigate the changes in intraocular cytokines after ranibizumab treatment in patients with polypoidal choroidal vasculopathy (PCV).Methods: This multicenter, prospective study enrolled patients with PCV treated with three monthly ranibizumab followed by a &lt;i&gt;pro re nata&lt;/i&gt; regimen for 24 weeks. Best corrected visual acuity, slit lamp examination, fundus photography, and optical coherence tomography were performed every 4 weeks. Aqueous humor was collected to measure intraocular cytokines at baseline, week 8, and the time of recurrence or week 20. The association of changes in intraocular cytokines with visual acuity, central macular thickness, central choroidal thickness, area of abnormal vessels, and polyp closure was assessed.Results: This study included 25 eyes. The mean patient age was 70.3 ± 6.1 years. The vascular endothelial growth factor (VEGF) concentration decreased at week 8, but only interferon (IFN)-γ, tissue inhibitors of matrix metalloproteinases (TIMP)-2, and monocyte chemoattractant protein (MCP)-2 decreased at the time of recurrence. The recurrence interval was positively associated with the baseline epithelial-neutrophil activating peptide (ENA)-78, interleukin (IL)-17, leptin, and transforming growth factor-β1, and baseline central macular thickness was positively correlated with the baseline fibroblast growth factor-4 and IL-10. Thick central choroidal thickness was associated with a low basic fibroblast growth factor and high IFN-γ at baseline. The MCP-3 and Tie-2 levels decreased in two eyes with polyp closure.Conclusions: Ranibizumab significantly reduced intraocular VEGF concentrations and consequently improved PCV. However, the cytokines IFN-γ, TIMP-2, and MCP-2, rather than VEGF, were associated with PCV recurrence. Further studies of intraocular cytokines involved in neovascularization in PCV are needed.

Revascularization of human ovarian grafts is equally efficient from both sides of the cortex tissue

Research questionDoes revascularization of human ovarian grafts in a mouse model occur with equal efficiency from both sides of the cortex tissue? DesignTwenty-four frozen-thawed ovarian cortex pieces from 12 women were transplanted to immunodeficient mice, for 8 days to analyse graft revascularization using immunohistochemical detection of murine CD31, or for 8 weeks to evaluate follicle density (follicles/mm3). The CD31-positive vessel area and density were quantified using a custom-designed application. Three regions of interest (ROI) were defined in each tissue section: the cortical side, the centre and the medullary side. Vessels were subdivided into three categories according to size: microvessels (<300 µm2), small vessels (300–1000 µm2) and large vessels (>1000–3000 µm2). ResultsNo significant difference in the mean percentage of the CD31-positive vessel area was found between the three ROI (cortical side: 3.9% ± 0.2%; centre: 3.5% ± 0.2%; medullary side: 4.0% ± 0.3%; P = 0.17), but a significantly lower density of vessels was found in the centre of the human ovarian grafts compared with the cortical and medullary sides (cortical side: 323 ± 14 vessels/mm2; centre: 240 ± 12 vessels/mm2; medullary side: 301 ± 18 vessels/mm2; P < 0.001). Microvessels comprised 89–91% of all vessels in the three ROI. Follicle density in ungrafted cortex pieces was 51.8 ± 17.3 and 14.7 ± 3.7 follicles/mm3 after 8 weeks of xenografting, resulting in a follicle survival rate of 28%. ConclusionsHost revascularization was established equally efficiently from both sides of transplanted human ovarian cortex, suggesting that transplantation techniques ensuring revascularization from both sides of the ovarian graft could potentially facilitate faster graft revascularization.

Can bleeding in trabeculectomy be decreased? Effectiveness of brimonidine pre-treatment

To evaluate the efficacy of preoperative topical brimonidine use to maintain visibility during trabeculectomy and control intraoperative bleeding and postoperative subconjunctival hemorrhage. The first group comprised 35 eyes of 34 patients administered brimonidine tartrate 0.15% (Brimogut, Bilim Ilac, Turkey) eye drops 6 and 3 min before surgery, and 33 eyes of 31 patients who received no medication for vasoconstriction formed the second group. Preoperative and postoperative photographs and operation video images were taken and vision analysis software used. Black-and-white images were obtained to identify the blood vessel and surface hemorrhage areas. The surface area of the hemorrhage was calculated by counting the black pixels with Image J software. There was no significant difference between two groups in terms of baseline (preoperative) eye redness (p > 0.05). In the first group, the eye redness values were 344.7 ± 19.5 pixels preoperatively and 244.1 ± 23.3 pixels at the beginning of the surgery, respectively (p < 0.001). However, no significant change was observed in the second group in eye redness (348.2 ± 17.5 pixels preoperatively and 360.7 ± 26.8 pixels at the beginning of the surgery, p > 0.05). Cautery was used for an average of 11.91 ± 1.96 s in the first group and 25.57 ± 4.66 s in the second to control intraoperative bleeding (P < 0.001). Preoperative topical brimonidine use in trabeculectomy surgery significantly decreased intraoperative bleeding and postoperative subconjunctival hemorrhage and facilitated bleeding control.

Quantitative analysis of branching neovascular networks in polypoidal choroidal vasculopathy by optical coherence tomography angiography after photodynamic therapy and anti-vascular endothelial growth factor combination therapy.

To study serial changes in branching neovascular networks (BNN) by using optical coherence tomography angiography (OCTA) in patients with polypoidal choroidal vasculopathy (PCV) who underwent combined photodynamic therapy (PDT) and anti-vascular endothelial growth factor (anti-VEGF) therapy. In this retrospective study of 30 PCV patients who underwent combined therapy, OCTA images obtained at baseline and 1, 3, and 6months after treatment were collected. The vessel area, vessel percentage area, average vessel length, and presence of polypoidal lesions on OCTA images as well as best-corrected visual acuity (BCVA), central retinal thickness (CRT), and central choroidal thickness (CCT) were recorded at each time point. The BNN- and polypoidal lesion-detection rates on baseline OCTA images were 100% and 71%, respectively. The vessel area decreased during the first 3months, and increased 6months post-treatment, showing significant differences from baseline (p = 0.031). The vessel percentage area also reduced 1 and 3months post-treatment (p = 0.025) and increased 6months post-treatment. Continuous polypoidal lesion regression was observed from 1 to 3 and 6months post-treatment (p = 0.031, p = 0.004, p = 0.002, respectively, in comparison with baseline). Patients with a decreasing vessel area over 6months showed greater choroidal thickness than those with increasing vessel area (p = 0.004). The BNN showed initial regression but were enlarged at 6months after therapy. Patients showing continuous BNN regression showed a thicker choroid at baseline. This difference should be considered during treatment for PCV, and OCTA could be used for follow-up evaluations of PCV patients.

Towards a Digital Twin of Coronary Stenting: A Suitable and Validated Image-Based Approach for Mimicking Patient-Specific Coronary Arteries

Considering the field of application involving stent deployment simulations, the exploitation of a digital twin of coronary stenting that can reliably mimic the patient-specific clinical reality could lead to improvements in individual treatments. A starting step to pursue this goal is the development of simple, but at the same time, robust and effective computational methods to obtain a good compromise between the accuracy of the description of physical phenomena and computational costs. Specifically, this work proposes an approach for the development of a patient-specific artery model to be used in stenting simulations. The finite element model was generated through a 3D reconstruction based on the clinical imaging (coronary Optical Coherence Tomography (OCT) and angiography) acquired on the pre-treatment patient. From a mechanical point of view, the coronary wall was described with a suitable phenomenological model, which is consistent with more complex constitutive approaches and accounts for the in vivo pressurization and axial pre-stretch. The effectiveness of this artery modeling method was tested by reproducing in silico the stenting procedures of two clinical cases and comparing the computational results with the in vivo lumen area of the stented vessel.

Vasculogenic Potency of Bone Marrow- and Adipose Tissue-Derived Mesenchymal Stem/Stromal Cells Results in Differing Vascular Network Phenotypes in a Microfluidic Chip.

The vasculature is an essential, physiological element in virtually all human tissues. Formation of perfusable vasculature is therefore crucial for reliable tissue modeling. Three-dimensional vascular networks can be formed through the co-culture of endothelial cells (ECs) with stromal cells embedded in hydrogel. Mesenchymal stem/stromal cells (MSCs) derived from bone marrow (BMSCs) and adipose tissue (ASCs) are an attractive choice as stromal cells due to their natural perivascular localization and ability to support formation of mature and stable microvessels in vitro. So far, BMSCs and ASCs have been compared as vasculature-supporting cells in static cultures. In this study, BMSCs and ASCs were co-cultured with endothelial cells in a fibrin hydrogel in a perfusable microfluidic chip. We demonstrated that using MSCs of different origin resulted in vascular networks with distinct phenotypes. Both types of MSCs supported formation of mature and interconnected microvascular networks-on-a-chip. However, BMSCs induced formation of fully perfusable microvasculature with larger vessel area and length whereas ASCs resulted in partially perfusable microvascular networks. Immunostainings revealed that BMSCs outperformed ASCs in pericytic characteristics. Moreover, co-culture with BMSCs resulted in significantly higher expression levels of endothelial and pericyte-specific genes, as well as genes involved in vasculature maturation. Overall, our study provides valuable knowledge on the properties of MSCs as vasculature-supporting cells and highlights the importance of choosing the application-specific stromal cell source for vascularized organotypic models.

Stem xylem traits and wood formation affect sex-specific responses to drought and rewatering in Populus cathayana.

The increased frequency and intensity of drought pose great threats to the survival of trees, especially in dioecious tree species with sexual differences in mortality and biased sex ratios. The sex-specific mechanisms underlying stem xylem anatomy and function and carbon metabolism in drought resistance and recovery were investigated in dioecious Populus cathayana Rehder. The sex-specific drought resistance and subsequent recovery were linked to the xylem anatomy and carbon metabolism. Females had a greater xylem vessel area per vessel, biomass and theoretically hydraulic efficiency under well-watered conditions. Conversely, males had a lower xylem lumen area, but greater vessel numbers, and a higher cell wall thickness, suggesting a theoretically conservative water-use strategy and drought resistance. The recovery of photosynthetic ability after drought in males was largely dependent on the recovery of xylem function and the regulation of the xylem carbohydrate metabolism. Additionally, the number of upregulated genes related to xylem cell wall biogenesis was greater in males relative to females under drought stress and subsequent rewatering, which facilitated drought resistance and xylem function restoration in males. These results suggested that sex-specific drought resistance and restoration were related to xylem anatomy and function, carbohydrate metabolism and cell turgor maintenance.

Optical coherence tomography angiography in herpetic leucoma

BackgroundHerpes simplex virus (HSV) keratitis remains a leading infectious cause of blindness worldwide. Although all forms of HSV keratitis are commonly recurrent, the risk is greatest in stromal keratitis, which is the most likely to result in corneal scarring, thinning, and neovascularization. Recent studies showed the ability of Optical Coherence Tomography Angiography (OCTA) to detect and study vascular abnormalities in the anterior segment, including abnormal corneal vessels. This study intends to investigate the potential of OCTA device to image and describe quantitatively the vascularization in eyes diagnosed with herpetic leucoma and to discuss and review the usefulness of this technique in this pathology.MethodsA Cross-sectional study was made, including 17 eyes of 15 patients with leucoma secondary to herpetic keratitis. All eyes underwent anterior segment Slit-Lamp photography (SLP), and OCTA with en-face, b-scans and c-scans imaging. The vessel density (VD) was analyzed in the inferior, nasal and temporal corneal margin in all patients, and in the central area, in eyes with central corneal neovascularization (CoNV). The measurements were calculated after binarization with ImageJ software, using OCTA scans with 6 × 6 mm in a depth of 800 μm.ResultsPatients included had a mean age 53.267 ± 21.542 (years ± SD). The mean total vessel area was 50.907% ± 3.435%. VD was higher in the nasal quadrant (51.156% ± 4.276%) but there were no significant differences between the three analyzed areas (p = 0.940). OCTA was able to identify abnormal vessels when SLP apparently showed no abnormal vessels; OCTA was able to distinguish between larger and smaller vessels even in central cornea; OCTA scans allowed the investigation of several corneal planes and the relation of them with clinical findings.ConclusionsOCTA can be useful in both qualitative and quantitative follow-up of patients and may become a non-invasive alternative to objectively monitor treatment response in eyes with corneal vascularization due to herpetic infection.

A Morphometric Analysis of Pathological Alterations in Hemorrhoidal Disease Versus Normal Controls: A Controlled Trial

Abstract Objective Until today, the true pathophysiology of hemorrhoidal disease (HD) has not yet been unraveled. More and more evidence guides us towards the hypothesis that reduced connective tissue stability is associated with a higher incidence of hemorrhoids. The present study aimed to compare the quantity and quality of collagen, and vessel morphometrics, in patients with symptomatic HD compared with normal controls. Methods Twenty-two samples of grade III and grade IV HD tissue from patients undergoing a hemorrhoidectomy between January 2004 and June 2015 were included in the study group. Samples of 15 individuals without symptomatic HD who donated their body to science and died a natural death served as controls. The quantity and quality of anal collagen, and anal vessel morphometrics were objectified. The quality of collagen was subdivided in young (immature) and old (mature) collagen. Results Patients with HD had an increased percentage of total anal collagen (62.1 ± 13.8 versus 18.7 ± 14.5%; p = 0.0001), a decreased percentage of young collagen (0.00009 ± 0.00008 versus 0.0008 ± 0.0008%; p = 0.001), and a smaller surface area of the anal vessels (795.1 ± 1215.9 micrometre2 versus 1219.0 ± 1976.1; p = 0.003) compared with controls. The percentage of old collagen did not differ between the control and study groups (0.588 ± 0.286% versus 0.389 ± 0.242%; p = 0.06). Conclusion The outcomes of the present study suggest that alterations in anal collagen composition may play a role in the formation of hemorrhoids.

Quantification of peripapillary vessel density in non-arteritic anterior ischemic optic neuropathy patients with optical coherence tomography angiography.

Quantitative assessments based on optical coherence tomographic angiography (OCTA) may have potential promising value in the early detection of non-arteritic anterior ischemic optic neuropathy (NA-AION), but there is limited information on the ability of OCTA to distinguish eyes with NA-AION. This study was conducted to evaluate the ability of measurements of peripapillary perfusion using OCTA to distinguish healthy eyes from eyes with NA-AION. In this retrospective case-control study, newly diagnosed NA-AION patients and healthy controls matched at a ratio of 1:3 by gender and age (±5 years) were enrolled from 1 September 2020 to 30 June 2021. Peripapillary vessel density (pVD) was examined based on the area of vessels by means of a 4.5 mm OCTA scan. In addition, peripapillary retinal nerve fiber layer (pRNFL) thickness was obtained from structural optical coherence tomography (OCT), as was the area under the receiver operating characteristic (ROC) curve (AUC). A total of 29 eyes from 28 cases with NA-AION and 99 healthy eyes from 68 participants were imaged. All participants were Chinese. The NA-AION group showed a significant reduction of the pVD (P<0.001), while all subregions of pRNFL thickness were prominent in all 8 quadrants (P>0.05). The pVD of the optic disc in the superior temporal (ST) region showed better diagnostic accuracy (AUC =0.86) in discriminating the NA-AION group from healthy controls. After adjusting for confounders, ST was independently associated with the presence of NA-AION [odds ratio (OR) =0.971, 95% confidence interval (CI): 0.943-0.990, P=0.048]. Decreased pVD was detected by non-invasive measurements of OCTA in the eyes of NA-AION patients. This finding may reveal an association between the ST region and the presence of NA-AION. The pVD may have potential diagnostic ability and may serve as an additional biomarker in the management of the disease.

A fully analytical model of a box solar cooker with sensible thermal storage

A box-type solar cooker supplemented with a sensible heat storage medium (for nocturnal cooking) has been analytically investigated. Unlike other available analytical studies where the relevant time interval is divided into a large number of smaller intervals and time marching is conducted numerically, here, a series of sinusoidal functions for time-dependent system driving parameters is considered via which fully closed form solutions are derived for cooking fluid and storage medium temperatures as functions of time. Here, the influences of storage medium mass and two newly defined parameters: cooking vessel area fractions for day and night cooking are investigated. Results reveal that the system’s performance increases with reduced storage medium mass and increased night cooking vessel area fraction. It is inferred that increased area of vessel at day, on one hand reduces day cooking time, while on other hand, raises the night cooking time, and therefore, its value must be selected by considering these two effects. Further, the calculations also predict that the maximum storage medium temperature is not attained at the end of sunshine period, but some time before it. Thus, charging of this medium must be stopped at the time beyond which its temperature begins to decrease. This work therefore lays down guidelines for the design of box type solar cookers with sensible thermal storage and can prove useful in predicting the appropriate time at which charging of storage medium must be ceased and also in selecting the cooking vessel dimensions for both day and night cooking.

Review on Diabetic Retinopathy Detection Using Molecular Segmentation In Convolution Neural Network

Abstract: People who suffer from diabetes are at risk of developing blindness since their pancreas doesn't produce enough insulin. Diabetic retinopathy is a condition in which a patient's vision gradually worsens as the disease advances. To better understand how diabetes affects the eye, retinal images captured with a fundal camera can be helpful. This study aims to detect blood vessels, identify hemorrhages, and classify different phases of diabetic retinopathy into normal, mild, and non-proliferative diabetic retinopathy (NPDR). When it comes to classifying the various stages of diabetes-related retinopathy, the retinal picture is used as a starting point. Using the contrast between the blood vessels and the surrounding background, the retinal vascular is segmented.. Density analysis and bounding box approaches were used to identify potential hemorrhage sites. According to blood vessel and hemorrhage area and perimeter, Random Forests technique was used to finally classify various phases of eye disease. Keywords: Retina, blood vessel, hemorrhages, classification, diabetic retinopathy.

A Comparative Analysis of the Hydraulic Strategies of Non-Native and Native Perennial Forbs in Arid and Semiarid Areas of China

(1) Background: Water transport systems play an important role in maintaining plant growth and development. The plasticity responses of the xylem anatomical traits of different species to the environment are different. Studies have shown that there are annual growth rings in the secondary root xylem of perennial herbaceous species. Studies on xylem anatomical traits, however, have mainly focused on woody species, with little attention given to herbaceous species. (2) Methods: We set 14 sampling sites along a rainfall gradient in arid and semiarid regions, and collected the main roots of native (Potentilla) and non-native (Medicago) perennial forbs. The xylem anatomical traits of the plant roots were obtained by paraffin section, and the relationships between the xylem traits of forbs were analyzed by a Pearson correlation. (3) Results: In the fixed measurement area (850 μm × 850 μm), the vessel number (NV) of Potentilla species was higher than that of Medicago species, while the hydraulic diameter (Dh) and mean vessel area (MVA) of Potentilla species were lower than those of Medicago species. With the increase in precipitation along the rainfall gradient, the Dh (R2 = 0.403, p = 0.03) and MVA (R2 = 0.489, p = 0.01) of Medicago species increased significantly, and NV (R2 = 0.252, p = 0.09) decreased, while the hydraulic traits of Potentilla species showed no significant trend with regard to the rainfall gradient. (4) Conclusions: The hydraulic efficiency of non-native Medicago forbs was higher than that of native Potentilla forbs, and the hydraulic safety of native Potentilla forbs was higher than that of non-native Medicago forbs. With the decrease in precipitation, the hydraulic strategies of non-native Medicago forbs changed from efficiency to safety, while native Potentilla forbs were not sensitive to variations in precipitation.