Response Of Vessels Research Articles

Abstract Number ‐ 63: A swine model to simulate the mechanism of aspiration thrombectomy.

Introduction Aspiration thrombectomy is an effective technique to recanalize large vessel occlusions (LVO) in stroke patients and has become one of the major techniques. Advancements in technology have enabled the use of catheters with larger lumens and higher aspiration forces; however, the successful reperfusion rate of the first pass remains at 57–63%. This poses a question as to why this rate is still suboptimal when conducting aspiration thrombectomy. We established a swine model for LVO, which provides concurrent fluoroscopic and transmural visualization of real‐time vessel responses during aspiration thrombectomy, to investigate the mechanism of aspiration thrombectomy. Methods Under general anesthesia, a common carotid artery (CCA) and a superficial cervical artery (SCA) of Yorkshire swine (n = 3) were surgically exposed, and an LVO was reproduced by injecting a radiopaque clot analog via a guiding catheter. Each target artery was treated using aspiration catheters with different inner diameters (0.058, 0.068, and 0.088 inches). The CCA group (n = 7) represented large diameter vessels (4‐5mm) simulating a human ICA, and the SCA group (n = 6), with bifurcations, represented small diameter vessels (2‐3mm) simulating a human MCA. To make a consistent clot location in the CCA group, mild, non‐flow‐limiting stenosis was created using a 4‐0 Prolene suture. Fluoroscopy and a high‐resolution digital microscope camera were used simultaneously to monitor angiographic and transmural vessel behavior during the procedure. Average vessel diameter, local blood pressures proximal and distal to the occlusion site, the presence or absence of vessel collapse / reverse flow during the procedures, and pre‐and post‐angiographic findings were evaluated. Results Both fluoroscopic and transmural visualization of mechanical thrombectomy was achieved in all vessels allowing the observation of real‐time arterial wall and clot response during the procedure. The mean blood pressures distal and proximal to the occlusion site showed no significant differences between the two groups. With remote aspiration, all vessels in the SCA group (Mean Diameter: 2.34 ± 0.49mm) showed immediate vessel collapse, and regardless of the lumen size of the catheter, they all failed to recanalize the vessels. Effective clot ingestion was achieved only when direct contact aspiration was applied (5 of 6 vessels). None of the vessels in the CCA group (Mean Diameter: 5.16 ± 0.54 mm) showed vessel collapse during remote aspiration. Six out of 7 vessels (85.7%) treated with remote aspiration showed local reverse flow followed by complete aspiration when the tip of the aspiration catheter was placed 5–20mm away from the clot. One CCA vessel required direct contact aspiration to achieve clot ingestion. Conclusions This swine model to analyze vessel behavior during aspiration thrombectomy may help us understand the mechanism of aspiration thrombectomy. The model may contribute to improving the techniques and the development of new aspiration devices.

The Association of High Sensitivity C-reactive protein and Nitric Oxide with Elevated Blood Pressure during Dialysis in Intradialytic Hypertension

BACKGROUND: Hemodialysis (HD) is a procedure to replace part of kidney function in patients with end-stage kidney disease. Hemodynamic disturbances during HD may include elevated blood pressure (BP). It is reported that about 5–15% of patients undergoing regular HD have increased BP during HD. This condition is called intradialytic hypertension (IDH). Increased high sensitivity C-reactive protein (hs-CRP) levels are associated with decreased endothelial dilatation response of blood vessels. Nitric Oxide (NO) is one of the mediators that act as a vasodilator to regulate vascular pressure. Endothelial dysfunction is one of the factors thought to contribute to the incidence of IDH. AIM: This study aimed to determine the association of hs-CRP and NO with elevated BP in IDH. METHODS: This observational cross-sectional study was conducted at Prof. Dr. R.D. Kandou General Hospital, Manado, from November 2021 to April 2022. Participants were selected through consecutive sampling methods. The levels of hs-CRP and NO were examined in all patients. The correlation between hs-CRP and NO was performed using the Spearman test, while the association of hs-CRP and NO with elevated BP was performed using the Fisher- exact test or Chi-square test. RESULTS: Forty patients were included in this study. The median hs-CRP, NO, and systolic BP (SBP) of the patients were 6.55 mg/dL (0.50–43.5), 27.77 mg/dL (3.65–72.19), and 20 mmHg (10–30), respectively. The correlation analysis showed that there was a strong significant negative correlation between hs-CRP levels and NO (r = −0.680, p = 0.000). Based on the Chi-Square or Fisher Exact test, there was a significant association between hs-CRP levels and elevated SBP (OR = 5.06; 95% CI = 1.095–23.44; p = 0.040), as well as between NO levels and elevated SBP (OR = 17.14; 95% CI = 3.063–95.938; p = 0.000). CONCLUSION: There was a significant association between hs-CRP and NO levels with elevated SBP in end-stage renal disease (ESRD) patients with IDH. ESRD on hemodialysis (ESRD on R-HD) patients with hs-CRP ≤3 mg/dL or NO levels <25 mg/dL tends to have increased SBP ≥20 mmHg after HD compared to ESRD patients with low hs-CRP or high NO levels.

Reactivity of renal and mesenteric resistance vessels to angiotensin II is mediated by NOXA1/NOX1 and superoxide signaling.

Activation of NADPH oxidase (NOX) enzymes and the generation of reactive oxygen species and oxidative stress regulate vascular and renal function and contribute to the pathogenesis of hypertension. The present study examined the role of NOXA1/NOX1 function in vascular reactivity of renal and mesenteric resistance arteries/arterioles of wild-type and Noxa1-/- mice. A major finding was that renal blood flow is less sensitive to acute stimulation by angiotensin II (ANG II) in Noxa1-/- mice compared with wild-type mice, with a direct action on resistance arterioles independent of nitric oxide (NO) bioavailability. These functional results were reinforced by immunofluorescence evidence of NOXA1/NOX1 protein presence in renal arteries, afferent arterioles, and glomeruli as well as their upregulation by ANG II. In contrast, the renal vascular response to the thromboxane mimetic U46619 was effectively blunted by NO and was similar in both mouse genotypes and thus independent of NOXA1/NOX1 signaling. However, phenylephrine- and ANG II-induced contraction of isolated mesenteric arteries was less pronounced and buffering of vasoconstriction after acetylcholine and nitroprusside stimulation was reduced in Noxa1-/- mice, suggesting endothelial NO-dependent mechanisms. An involvement of NOXA1/NOX1/O2•- signaling in response to ANG II was demonstrated with the specific NOXA1/NOX1 assembly inhibitor C25 and the nonspecific NOX inhibitor diphenyleneiodonium chloride in cultured vascular smooth muscle cells and isolated mesenteric resistance arteries. Collectively, our data indicate that the NOX1/NOXA1/O2•- pathway contributes to acute vasoconstriction induced by ANG II in renal and mesenteric vascular beds and may contribute to ANG II-induced hypertension.NEW & NOTEWORTHY Renal reactivity to angiotensin II (ANG II) is mediated by superoxide signaling produced by NADPH oxidase (NOX)A1/NOX1. Acute vasoconstriction of renal arteries by ANG was blunted in Noxa1-/- compared with wild-type mice. NOXA1/NOX1/O2•- signaling was also observed in ANG II stimulation of vascular smooth muscle cells and isolated mesenteric resistance arteries, indicating that it contributes to ANG II-induced hypertension. A NOXA1/NOX1 assembly inhibitor (C25) has been characterized that inhibits superoxide production and ameliorates the effects of ANG II.

Acute hyperglycemia compromises the responses of choroidal vessels using swept-source optical coherence tomography during dark and light adaptations.

To clarify the effects of acute hyperglycemia on the responses of choroidal structural components and vascularity index during light modulation in healthy participants using techniques including image binarization and artificial intelligence (AI) segmentation based on swept-source optical coherence tomography (SS-OCT). Twenty-four eyes of 24 healthy participants were imaged at different stages after ambient light, 40 min of dark adaptation, and 5 min of light adaptation in two imaging sessions: control and after receiving 75 g of oral glucose solution. The choroidal structural parameters, including luminal volume (LV), stromal volume (SV), total choroidal volume (TCV), and choroidal vascularity index (CVI) within a 6 mm area were determined using a custom algorithm based on image binarization and AI segmentation of SS-OCT. These measurements were compared among the conditions after adjusting for axial length, age to identify the differences. In the dark, CVI decreased (-0.36 ± 0.09%) significantly in acute hyperglycemia compared to the control condition. During the transition to ambient light, there was an increasing trend in the choroidal parameters compared with the control experiment. However, only TCV (0.38 ± 0.17 mm3) and LV (0.27 ± 0.10 mm3) showed a significant increase at the time point of 5 min after ambient light. Analysis of choroidal structural parameters and CVI based on SS-OCT images is a potentially powerful method to objectively reflect subtle changes in neurovascular coupling between the choroid and photoreceptor during dark adaptation.

Variability of Vascular Reactivity in the Retina and Choriocapillaris to Oxygen and Carbon Dioxide Using Optical Coherence Tomography Angiography.

To investigate the regional and layer-specific vascular reactivity of the healthy human retina and choriocapillaris to changes in systemic carbon dioxide or oxygen. High-resolution 3 × 3-mm2 optical coherence tomography angiography (OCTA) images were acquired from the central macula, temporal macula, and peripapillary retina while participants were exposed to three gas breathing conditions-room air, 5%CO2, and 100% O2. OCTA from all three regions were extracted and the apparent skeletonized vessel density (VSD) was assessed. The mean flow deficit sizes (MFDSs) of the choriocapillaris were also assessed. Repeated-measures analysis of variance was used to compare the ratio of intrasubject VSD change induced by the gas conditions from baseline in the superficial retinal layer (SRL) and deep retinal layer (DRL) for each retinal region independently, as well as the MFDS of the choriocapillaris. We also compared the vessel reactivity between the retinal capillaries and the choriocapillaris. The cumulative intrasubject response to the gas conditions differed significantly among regions of the SRL (F(2, 7) = 28.22, P < 0.001), with the temporal macula showing the largest response (15%) compared to the macula (8%) and radial peripapillary capillaries (7%). A similar trend was found in the DRL. The choriocapillaris reactivity was similar between the macula (5.8%) and temporal macula (5.6%). There was also a significant heterogeneity in the layer-specific gas responses, with the DRL showing the largest response (28.2%) and the choriocapillaris showing the smallest response (2.8%). Capillary reactivity to changes in inhaled O2 and CO2 is spatially heterogeneous across the retina but not choriocapillaris.

Numerical method and experimental validation of the magneto-thermal-mechanical coupling problem with application to tokamak structures

Tokamak is a kind of device that uses strong magnetic fields to confine the hot nuclear fuel in plasma state and achieve the controlled thermonuclear fusion reaction. It is well-known that increasing the plasma elongation is beneficial for improving the performance of tokamak. However, high elongation is always along with a strong intrinsic vertical instability. The control system to neutralize the vertical instability of the plasma may fail. As a result, the plasma will move vertically and finally strike on the plasma-facing components accompanied by rapid thermal and current disruption. During this process, large eddy currents will be induced in the plasma surrounding conductive structures and high heat flux will be injected into the first wall of the vacuum vessel (VV). The eddy currents and the temperature gradient then produce strong Lorentz forces and thermal stress, which may cause excessive deformation or even failure of the device. Additionally, there are complicated magneto-thermal-mechanical coupling (MTMC) phenomena in the dynamics of the tokamak structures, which may have non-negligible influences on the distribution of the electromagnetic and mechanical loads and the dynamic response of the structure. To ensure the safety of the tokamak device, it is necessary to make quantitative evaluations of the coupling effects on the transient response of the VV and in-vessel structures during plasma disruptions. In this paper, efficient numerical methods were proposed for solving the structural dynamic problem with MTMC effects. The nonlinear interaction between the magneto-mechanical terms was linearized with a block-Gauss-Seidel iterative algorithm, and an adaptive matrix update algorithm was proposed to cope with the temperature effect on material properties. In addition, an MTMC experiment system with both electromagnetic load and thermal load was set up to demonstrate the validity and efficiency of the proposed numerical methods. Finally, the dynamic response of the vacuum vessel of HL-2M tokamak during a typical plasma disruption was simulated using our updated numerical code, and influences of the MTMC effects were quantitatively evaluated.

Investigation on the effect of bow configuration on motion and green water for tumblehome vessels based on cartesian grid finite difference method

The special bow design of the tumblehome vessel makes it easy to produce green water, resulting in serious damage to the superstructure. However, the harsh environment numerical studies supported by experimental data on the bow configuration of tumblehome vessels are few. Based on the Cartesian Grid Finite Difference Method (CGFDM), this paper studied the motion response of the ship and the green water characteristics in regular waves under different bow configurations. The Finite Difference Method (FDM) based on a fixed regular staggered Cartesian grid system is used to solve the flow field, and the Tangent of Hyperbola for Interface Capturing with Slope Weighting (THINC/SW) scheme is used to capture the severe free surface flow. At the same time, the immersed boundary method is used to effectively solve the problem of the large motion of the object. The numerical simulation results were compared with the experimental values, showing good consistency. The calculation results show that the bow configuration has little effect on the motion response of the tumblehome vessel in regular waves and only shows some local differences in some wave conditions. Macroscopically, the change of stem angle has little effect on the green water degree of the ship. However, under high wave conditions, the change of stem angle greatly influences the height of green water and the slamming pressure characteristics of the ship. Compared with the bow configuration schemes with stem angles of 30° and 60°, the ship with the stem angle of 45° has a better comprehensive load performance when green water occurs. This study can provide a suitable reference for selecting ship types and structural designs of tumblehome vessels.

Elastic response analysis of cylindrical vessels subjected to internal explosion

Strain growth and buckling are typical phenomena of pressure vessels under internal explosion load. To study the mechanism of the strain growth and buckling phenomena, the numerical simulations are performed by LS-DYNA to study the elastic response of the cylindrical vessels under internal explosion. The results show that for the cylindrical vessel with a free boundary, the response of the vessel is a breathing-like mode under the small explosive loading. When the explosive loading becomes larger, the response of the vessel is a breathing-like mode in the early stage and a coupling of breathing-like mode and buckling response in the late stage. The phenomenon of buckling is caused by large bending deformation. According to the response characteristics of the vessel at different stages, an improvement to the traditional idea of strain growth phenomenon was proposed, and the strain growth phenomenon is split into two stages: the first stage is defined as the strain fluctuation stage of the vessel in the breathing-like mode; the second stage is defined as the strain growth stage of the vessel evolving from the breathing-like mode to the buckling mode. The results show that the buckling phenomenon will increase the displacement of the container, but it does not necessarily lead to strain growth phenomenon and sometimes it may even weak the strain. There is an edge effect is found during the study, which must have to lead an increase in the degree of the response of the vessel.

Structural Response of Double-Layer Steel Cylinders under Inside-Explosion Loading

The research on the structural response of explosive vessel is an important basis for the design of explosive vessels. Double-layer cylinder structures are widely used in the design of various explosive vessels. This paper studied the deformation of a steel cylindrical shell under internal explosion and proposes a new method for measuring shell deformation by PDV (photonic Doppler velocimetry). We carried out many spherical explosive experiments and obtained useful results that show displacement of the double-layer cylinders and the explosion time. The above process is a simulated LS-DYNA with a finite element numerical simulation. The vibration period of the outer cylindrical shell and the time for reflection of the stress wave in the outer cylindrical shell were obtained by numerical simulation and PDV measurement, respectively. The results of both can be verified against each other. Through the above research, the structural response of the multilayer cylinders can be obtained, which can provide further help with research of the structural design of multilayer cylinders.

An SPH study of slamming and splashing at the bow of SYSU vessel

Operating in extreme sea conditions, vessels often meet horrible wave impact which generates wave breaking and splashing at the bow and poses a great threat to staff safety and structural strength. Characterized with the ticklish issues e.g. multiphase interface and free surface large deformation, the study of slamming and splashing needs more reliable numerical tools. Smoothed particle hydrodynamics (SPH) method, benefiting from its Lagrangian meshless nature, shows superior performance in simulating slamming and splashing properties, which is employed in this paper to model the slamming process of the Sun Yat-sen University (SYSU) scientific research vessel. 2D wedges and 3D hemisphere water-entry benchmarks are simulated to validate the SPH model. After extending 2D to 3D simulation, SPH-based and finite volume method (FVM) -based solvers are exploited with various slamming cases for the SYSU scientific research vessel. Comparisons of the numerical results on dynamic response and bow slamming hydrodynamics of the SYSU vessel between SPH and FVM are performed in this paper. The numerical results demonstrate that except for precise prediction of hull dynamics, SPH is good at tracking the complex interface and splashing details, which possesses practical applicability in the simulation of violent fluid–structure interaction.

Circumferential Strain as a Marker of Vessel Reactivity in Patients with Intradialytic Hypotension.

Background and Objectives: Intradialytic hypotension (IDH) complicates 4 to 39.9% of hemodialysis (HD) sessions. Vessels' reactivity disturbances may be responsible for this complication. Two-dimensional speckle tracking is used to assess arterial circumferential strain (CS) as a marker of the effectiveness of the cardiovascular response to the reduction of circulating plasma. Materials and Methods: The common carotid artery (CCA) and common iliac artery (CIA) CSs were recorded using ultrasonography in 68 chronically dialyzed patients before and after one HD session. Results: In patients with IDH episodes (n = 26), the CCA-CS was significantly lower both before (6.28 ± 2.34 vs. 4.63 ± 1.74 p = 0.003) and after HD (5.00 (3.53-6.78) vs. 3.79 ± 1.47 p = 0.010) than it was in patients without this complication. No relationship was observed between CIA-CS and IDH. IDH patients had a significantly higher UF rate; however, they did not differ compared to complication-free patients either in anthropometric or laboratory parameters. Conclusions: Patients with IDH were characterized by lower pre- and post-HD circumferential strain of the common carotid artery. The lower CCA-CS showed that impaired vascular reactivity is one of the most important risk factors for this complication's occurrence.

Noninvasive Monitoring of Intracranial Pulse Waves.

The clinical management of several neurological disorders benefits from the assessment of intracranial pressure and craniospinal compliance. However, the associated procedures are invasive in nature. Here, we aimed to assess whether naturally occurring periodic changes in the dielectric properties of the head could serve as the basis for deriving surrogates of craniospinal compliance noninvasively. We designed a device and electrodes for noninvasive measurement of periodic changes of the dielectric properties of the human head. We characterized the properties of the device-electrode-head system by measurements on healthy volunteers, by computational modeling, and by electromechanical modeling. We then performed hyperventilation testing to assess whether the measured signal is of intracranial origin. Signals obtained with the device on volunteers showed characteristic cardiac and respiratory modulations. Signal oscillations can be attributed primarily to changes in resistive properties of the head during cardiac and respiratory cycles. Reduction of end-tidal CO2, through hyperventilation, resulted in a decrease in the signal amplitude associated with cardiovascular action. Given the higher CO2 reactivity of intracranial vessels compared to extracranial ones, the results of hyperventilation testing suggest that the acquired signal is, in part, of intracranial origin. If confirmed in larger cohorts, our observations suggest that noninvasive capacitive acquisition of changes in the dielectric properties of the head could be used to derive surrogates of craniospinal compliance.

S-36-2: SOCIAL FRAMEWORK TO PROMOTE SALT REDUCTION AND HEALTHY DIETS WITHIN HYPERTENSION AND STROKE PREVENTION

Beyond the physiological effects of sodium and potassium strong evidence from animal, clinical and epidemiological studies, has implicated excess dietary sodium and low potassium intake as major factors associated with the development of hypertension and increase in stroke risk. Daily salt intake of 5–6 g 85–100 mmol was recommended for the general population i.e. 2.0–2.4 g Na along with K intake to at least 90 mmol d 3.51 g perd. Randomized trials demonstrate that salt reduction and potassium increase in diet lowers blood pressure and reduces the risk of brain damage and cardiovascular disease. Population studies showed that 15 percent reduction of salt intake from 9.5 g/day was associated with a 40 percent reduction of stroke and CHD mortality. Potassium lowers BP via multiple mechanisms, by acting directly on the vasculature and by triggering a signalling cascade mediated by endothelium and also reduces salt-sensitivity. A meta-analysis of 21 RCTs reported that increasing potassium intake lowers BP 3.5/2.0 mm Hg and the risk of stroke. Eating more than 11 g of salt /day was associated with 2.5 times more likely to have a stroke than those who got less than 4.5 g /day. Switching from regular salt to a salt substitute reduced the risk for stroke, major CV events and death in a large trial of adults in rural China with a history of stroke or high risk for stroke. High salt intake reduces resting cerebral blood flow and induces endothelial dysfunction in mice and impairs vasodilatory responses of cerebral vessels. Gut-brain relation links dietary salt to cognitive impairment though a gut-initiated adaptative immune response damaging brain function via increase in circulating IL-17. A high potassium diet reduces cerebral infact size and improves vascular function independently of BP changes. Thus high salt and low potassium intake interfere in multtiple brain vascular strutural complex processes including fluid homeostasis and inflammatory mechanisms, immune responses and gut-microbiome-brain axis.

CGMP signaling: a potential therapeutic target for neurodegeneration in glaucoma?

cGMP signaling: a potential therapeutic target for neurodegeneration in glaucoma?

Mesenteric Artery Reactivity in the Development of Metabolic Syndrome in Rats Fed on a High-Fat Diet

Higt fat diet can lead to the development of metabolic syndrome (MS). However, the question of the mechanisms of pathophysiological processes in MS has not been studied enough. The aim of the work was to study the effect of a high-fat diet (HFD) on the reactivity of the mesenteric arteries of Wistar rats in vivo, as well as to evaluate the change in the mechanisms of endothelium-dependent arterial dilatation in HFD. The HFD-group of rats (n = 25) received HFD containing 50% animal fat for 10 weeks, the control group (n = 25) received a standard diet. The effect of HFD on endothelium-dependent and endothelium-independent responses of the mesenteric arteries under the action of agonists in the absence and with the use of blockers of NO-synthase (L-NAME), cyclooxygenase (indomethacin), and K+-channels (tetraethylammonium) was assessed using photomicrography and video recording of mesenteric artery diameter in vivo. HFD in rats led to the development of MS, including dyslipidemia, hyperglycemia and insulin resistance, and an increase in blood pressure. MS was accompanied by impaired functional state of the mesenteric arteries. In rats of the HFD group, compared with the control group, there was an increase in the constrictor reaction to phenylephrine by 29%, as well as a decrease in the reactivity of vessels previously contracted by phenylephrine under the action of acetylcholine by 36%. Pre-incubation of vessels with blockers reduced the amplitude of relaxation under the action of acetylcholine, compared with the initial acetylcholine-induced vasorelaxation, in HFD-group rats: with L-NAME – by 47%, L-NAME and indomethacin – by 50%, L-NAME, indomethacin and tetraethylammonium – by 65%; in the control group – by 69, 72 and 83%, respectively. HFD had no significant effect on the amplitude of vasodilation under the action of sodium nitroprusside. Thus, endothelial dysfunction in HFD-treated rats was mediated both by impairment of NO-dependent mechanisms of vasodilation, in particular, by a decrease in NO production by the endothelium, and by a decrease in the effectiveness of ВКСа. The decrease in NO bioavailability in HFD was partially compensated by the activation of endothelial hyperpolarization mechanisms (mediated by IKCa and SKCa activities) in acetylcholine-induced vasodilation.

The effects of inflammatory and acidosis insult on placental blood vessels reactivity

The effects of inflammatory and acidosis insult on placental blood vessels reactivity

Comparative assessment of vessel reactivity in medication-related osteonecrosis of the jaw

Comparative assessment of vessel reactivity in medication-related osteonecrosis of the jaw

Raynaud's Phenomenon: A Brush Up!

Raynaud's Phenomenon: A Brush Up!

Structural response validation of composite cylindrical pressure vessels using FEA

Cylindrical pressure vessels constructed using filament winding technique are a good example of the advantages that fibre-reinforced composite materials offer over common structural materials on a specific/unit weight basis. The high specific properties of composite materials over metals can reduce the weight of pressure vessels with a high potential for applications in submarines and ROV/AUV. An innovative method for the optimisation of composite cylindrical structures is through simulation of the pressure vessel response using as parameterised finite element model. In this paper the effect of boundary conditions has been analysed for a cylindrical pressure vessel of carbon-epoxy composite material subjected to internal pressure. For the said study, a parametric Finite Element model using an 8 noded layered solid brick element has been created in the finite element analysis software ANSYS using its Parametric Design Language features. The elasticity solution for a single layer circular tube has also been presented in reference to the works of Herakovich and Pindera towards validation of the numerical model. Pressure vessel finite element models, with different boundary conditions have been used to study convergence in comparison to the exact solution. A comparison of the through thickness distribution of stresses from different finite element cylindrical models in ANSYS against the exact solution for a composite tube under internal pressure have been presented for the validation of the numerical model and proposed boundary conditions. It has been demonstrated that only one element in circumferential direction using displacement coupling conditions at the boundary is sufficient, which would significantly enhance the computational efficiency of a structural analysis and make these models computationally efficient even for a non-linear analysis with axi-symmetric loads for both static and dynamic cases.

Experimental study of combined photodynamic and photothermal therapy in the treatment of port wine stain.

Laser therapy has become the golden standard of port wine stain (PWS), but complete clearance of resistant PWSs is still difficult. The application of photodynamic therapy (PDT) in the treatment of PWS shows potential in clinical practice, especially for large-area and deep lesions. In this work, in vivo animal experimental investigation on the coupling effect of PDT with multi-pulse laser (MPL) irradiation on the treatment of PWS was conducted by using a dorsal skin window chamber model. Through visualization of the thermal response of blood vessels and damage evaluation, it is found that the combination of PDT with MPL results in 96.2% more vascular injury than PDT alone and 90% more than MPL alone, thus reducing side effects such as purpura after treatment. The combined therapy also has the benefit of large treatment area, uniform fading effect, shortened light duration, and reduced photosensitizer admit.