The iliofemoropopliteal artery significantly changes path length during normal hip and knee flexion. Prosthetic bypass grafts, such as polytetrafluoroethylene (PTFE) grafts, are relatively stiff and thus can subject graft anastomoses to high tension when the path length increases. The aim of this study was to examine the influence of length redundancy and twist on the biomechanical properties of PTFE bypass grafts.Unreinforced and ring-reinforced PTFE grafts were loaded in an axial mechanical testing machine to measure the tensile and compressive axial forces with varying levels of length redundancy and axial twist.Adding 5-15% length redundancy to a graft decreases the force to cause 5% extension by > 90% without substantially increasing shortening forces. Adding 4.5°/cm of axial twist imparts a corkscrew shape to the graft without increasing extension or shortening forces in the presence of length redundancy. Ring-reinforced PTFE grafts require more length redundancy to experience these reductions in forces especially in the presence of axial twist.A modest amount of length redundancy and twist  confers improved biomechanical properties in a PTFE graft, especially in ring-reinforced grafts. This should be taken into consideration when fashioning an arterial bypass graft in the iliofemoropopliteal segment. The iliofemoropopliteal artery significantly changes conformation and path length during normal hip and knee flexion because of the iliofemoral artery being anterior to the hip joint and the popliteal artery being posterior to the knee joint.Prosthetic bypass grafts, such as polytetrafluoroethylene (PTFE) grafts, are relatively stiff and manufactured as straight tubular structures. However, a growing body of evidence suggests corkscrew/spiral-shaped vascular conduits improve the hemodynamics of blood flow.The aim of this study is to examine the influence of length redundancy and twist on the biomechanical properties of PTFE bypass grafts. We hypothesize that redundancy of graft length reduces the tensile forces on the anastomoses of a vascular graft in the lengthening direction without sacrificing compressive properties in the shortening direction. We further hypothesize that a slightly twisted (corkscrew-shaped) graft may be able to accommodate length change more smoothly, thus improving the mechanical properties of the bypass graft while conveniently improving hemodynamics.We chose representative types of PTFE grafts with 8-mm diameter for the experiments. Plain and ring-reinforced (Atrium Hybrid PTFE vascular graft) vascular surgical grafts were used for axial extension and shortening testing on an “Instron” mechanical testing machine (Model #5582 with a 100N load cell) . For eacWe further tested the tensile load versus axial extension and compressive load versus axial compression for the plain and ring-reinforced grafts, both while taut and untwisted, and with 10% slack and 45° twist . This shWe measured the changes in axial load required to cause 5% extension and 5% and 10% shortening in a graft with the addition of various levels of slack as compared with the taut and untwisted configuration A. This dWe further measured the changes in axial load required to cause 5% extension and 5% and 10% shortening in a graft with the addition of 45° of twist (4.5°/cm) as compared with the untwisted configuration B. There We assessed the axial load required to cause 5% extension and 5% and 10% shortening in a graft with the addition of 10% slack and 45° of twist (4.5°/cm) as compared with the untwisted configuration with 0%, 5%, 10%, and 15% slack C. There The addition of varying amounts of graft length redundancy  significantly affected the forces generated during extension and shortening testing of plain and ring-reinforced vascular grafts. When either graft design is taut, extension of even 5% requires substantial tensile force due to the relatively high stiffness in the graft material. This is exacerbated in the ring-reinforced design because ring reinforcement augments effective stiffness. Adding redundancy to the graft length ameliorates this problem by practically eliminating the required tensile force to lengthen the graft path length (reduction of >90%). This happens because the graft material is not significantly strained.Interestingly, this dramatic reduction in tensile lengthening force is not sensitive to the amount of graft redundancy as long as the graft never exceeds the taut state. Slack ranging from 5 to 15% does not appear to affect the reduction in axial load. Because ring-reinforced grafts require more force to deform, they exhibit greater reduction in axial load from additional slack than plain grafts. In addition, the extra graft redundancy is not at all detrimental to compressive forces needed to shorten the graft path length. This is because once the graft is past the point of slack and has buckled, further buckling requires relatively little additional force. Note that the ring-reinforced graft requires more compressive force to shorten the graft path length than the plain graft because the structure of the ring-reinforced graft causes higher effective stiffness.While adding redundancy to the graft length is highly effective at reducing tensile forces during lengthening and not detrimental to compressive forces during shortening, adding axial twist to the graft appears to cause increased tensile forces during path lengthening in the presence of low redundancy. Twist rotates material fibers away from being parallel to the axis of the graft, whereas axial extension requires these angled fibers to be realigned toward being parallel to this axis. This realignment requires shear strain between these angled fibers and thus additional axial tension. This is especially apparent in ring-reinforced grafts, which is consistent with their higher effective stiffness. Conversely, the presence of axial twist does not appear to substantially impact the required compressive force to shorten the path length of a graft.The knee is usually placed in a flexed position during the performance of a below knee popliteal bypass graft anastomosis to allow adequate exposure through a medial approach. It is routine practice to allow some redundancy in the graft in anticipation of the additional length required when the knee is fully extended. Our results suggest adding additional amount of slack to a vascular graft in vivo could dramatically reduce tensile loads on the anastomotic sites during path lengthening. For example, during hip and knee extension, the straight path length of the iliofemoropopliteal vessels can increase by 10% or more, so that adding slack to the graft may benefit.In this bench experiment design, we did not simulate the pulsatile blood flow and support of surrounding tissue which may prevent kinks in the graft. The axial force measurements were performed in a quasistatic state, meaning that: (1) while the forces may not be representative of actual in vivo forces, the results are instructive for any type of graft material/design because we eliminated inertial effects and (2) the results underestimate in vivo forces as vascular graft material is generally strain-rate hardening, so the importance of providing slack in a vascular graft may be heightened. We chose only two types of grafts and one diameter (8 mm) as representations of the synthetic graft types commonly used for femoral popliteal bypass. Further work will be required to demonstrate the external validity of our observations in vivo.A modest amount of length redundancy and twist (i.e. a cork-screwed condition) confers improved biomechanical properties in a PTFE graft. This should be taken into consideration when fashioning an arterial bypass graft in the iliofemoropopliteal segment. Alternatively, a highly axially compliant graft would accommodate the dynamics of the leg.


EJNMMI Radiopharmacy and Chemistry by an international working group of experts, the EJNMMI journal family endorses the application of the guidelines in contributions to the journals.With the open letter published in Attached to the letter by the working group is a 3-page summary highlighting the most relevant issues used in the notation of radiopharmaceuticals and related terms.The full paper with all recommendations is published in “Consensus nomenclature rules for radiopharmaceutical chemistry — setting the record straight, Coenen, H.H., Gee A.D. et al., Nuclear Medicine and Biology, Volume 55, v – xi (2017) (10.1016/j.nucmedbio.2017.09.004).”All Editors-in Chiefs of the EJNMMI journals strongly recommend all manuscripts meet these guidelines upon submission. In addition, all reviewers will be asked to be aware of the guidelines and wherever possible to check if the guidelines are followed.Editors-in-Chief,Philip ElsingaAngelika Bischof DelaloyeArturo ChitiStefaan VandenbergheFrancesco GiammarileIgnasi Carrio


The sterilization efficacy and the influence of the treatment on the aerogel final properties were evaluated mainly in terms of absence of microbial growth, cytocompatibility, as well as physicochemical, structural, and mechanical modifications.Aerogels from natural polymers are endowed with attractive textural and biological properties for biomedical applications due to their high open mesoporosity, low density, and reduced toxicity. Nevertheless, the lack of macroporosity in the aerogel structure and of a sterilization method suitable for these materials restrict their use for regenerative medicine purposes and prompt the research on getting ready-to-implant dual (macro + meso)porous aerogels. In this work, zein, a family of proteins present in materials for tissue engineering, was evaluated as a sacrificial porogen to obtain macroporous starch aerogels. This approach was particularly advantageous since it could be integrated in the conventional aerogel processing method without extra leaching steps. Physicochemical, morphological, and mechanical characterization were performed to study the effect of porogen zein at various proportions  on the properties of the obtained starch-based aerogels. From a forward-looking perspective for its clinical application, a supercritical CO The increase in life expectancy, the popularization of physical activity in society, and the high obesity ratios have strongly increased the incidence of bone diseases and traumatic fractures. The scarcity of donor grafts and the associated clinical complications (autoimmune response) even with autologous procedures , have prompted the development of innovative synthetic grafts (scaffolds) . A 3D hiAerogels are lightweight materials with outstanding textural properties that allow the manufacturing of multishape structures from different inorganic and organic sources ,6. SinceAerogels display a defined microstructure   mimickinZeins are the main storage proteins found in the seeds of corn, and are widely used in a variety of products . Specifi2 can inactivate a wide range of microorganisms, including bacterial spores , cylindrical, white, and monolithic starch aerogels with dual porosity were obtained through the addition of zein as a sacrificial porogen and regardless of the zein content used ([Z1] and [Z2] in The dehydration stage (solvent exchange) and the porogen leaching stage were brought together taking advantage of the differing solubility behavior in water and in ethanol of zein (insoluble in water) and corn starch (insoluble in ethanol) ,34. Prevw/w) containing zein in 0:1 ([Z0] aerogel), 1:2 ([Z1]), and 1:1 ([Z2]) weight ratios with respect to the starch content were chosen as optimal for evaluating the porogen addition effect, regarding suitable gel integrity, and the required midrange times for the porogen leaching. All the tested starch aerogel formulations had a volume reduction (shrinkage) after the serial water-to-ethanol solvent exchanges and the supercritical drying steps with respect to the initial volume of the gel dispersions (ΔV in Corn starch aqueous solutions of 10% (ns ΔV in . The volns ΔV in  was a sins ΔV in . The preBulkρ in ε) of starch aerogels followed the reverse trend as with the bulk density values and were in the 85–91% range, comparable to those of cancellous human bone [The zein-free starch aerogels [Z0] had higher bulk densities than [Z1] aerogels ρBulk in  due to aman bone .2 adsorption-desorption tests. The average pore diameter  slightly varied between formulations (16–19 nm), being the highest value for [Z0] aerogels. A decreasing trend was appreciated in the specific pore volume  values as the added zein amount increased (BET) were obtained for the manufactured aerogels (143–208 m2/g), which correlate with those reported for high amylose content (>40%) starch aerogels  was similar to that of starch raw material according to the ATR-FT-IR results . Therefo storage . AccordiSEM imaging was performed to evaluate the inner morphology of each aerogel formulation. All starch aerogel formulations were formed by a characteristic fibrous network a–c,f andMaterial surface roughness and topography are amongst the physicochemical properties that conditions the adhesion of cells to the scaffolds among other cell functions ,44. A toca. 25%) without fracture (p < 0.05) between the formulations regarding their mechanical behavior.The mechanical compatibility of the starch aerogels with regenerative medicine applications and the effect of the zein porogen on the mechanical properties were studied by compressive mechanical tests. The cylindrical probes experimented plastic deformation . All the tested formulations were sterile using the scCO2 method a, regardeatments ,52,53 an2 sterilization treatment can overcome the limitations of penetration capacity in porous materials like aerogels, which is encountered in other sterilization techniques like gamma, e-beam and UV-irradiation S  was observed for [Z0]s starch aerogels. For the starch aerogels processed with zein ([Z1]S and [Z2]S), this effect was counteracted by the decrease in the macroporous contribution to the aerogel porosity, as the ABET and VP,BJH values were almost unaltered or even slightly increased  obtained between both groups  also concreased . The mech groups .2 sterilization treatment, the biocompatibility of the aerogel formulations was determined by evaluating the viability of MSCs cells after 24 and 48 h of culture in the presence of the scaffolds. The cell proliferation WST-1 reagent was employed for quantification of cell viability since the enzymatic degradation of the said reagent into formazan directly correlates to the number of metabolically active cells. Cell viabilities close to 100% were obtained for the aerogels formulations modified with zein , regardless of the period of culture tested  was supplied by Praxair, Inc. . Sterilization reel were purchased from E-line S.r.l. . Commercial spore strips with 106 spores of Bacillus stearothermophilus (ATCC 7953) and Bacillus pumilus (ATCC 27142) were purchased from Sigma-Aldrich, Inc.  and Bacillus atrophaeus (cell line 9372) spores were obtained from Crosstex International, Inc. . Absolute ethanol (EtOH) was provided by VWR . T. Trypticase soy broth (TSB) medium was purchased from BIOKAR Diagnosis  and hydrogen peroxide 30% (v/v) from Sigma-Aldrich, Inc. . Human bone marrow-derived mesenchymal stem cells (ATCC® PCS-500-012™) were obtained from the American Type Culture Collection . Minimum Essential Medium Alpha (αMEM) and Opti-MEMTM were purchased from Thermo Fisher Scientific . Fetal bovine serum and penicillin 10,000 U/mL–streptomycin 10 mg/mL were supplied by Sigma-Aldrich . Cell proliferation reagent WST-1 was supplied by Roche .Native corn starch (52.6% amylose content) was provided by Roquette Frères S.A. . Zein  was purchased from Sigma-Aldrich, Inc. . COw/w) were prepared with zein added as porogen agent in different zein-to-starch weight ratios . The mixtures were autoclaved at 121 °C and 1.1 bar for 20 min  for starch gelatinization. The resulting aqueous solutions were stirred at 1500 rpm for 30 s with a magnetic stirrer  to ensure homogeneity, and then dosed in cylindrical polypropylene molds  and settled for gelation for 20 min at room temperature. Gels were then stored at 4 °C for 48 h to enhance the starch retro-gradation. Afterwards, starch-based gels were immersed in absolute ethanol for solvent exchange and porogen (zein) leaching. To ensure the removal of the zein, the solvent was replaced until no zein was detected in the ethanol by UV-Vis spectrophotometry  at a wavelength of λ = 279 nm and at room temperature. Prior to the measurements, a calibration curve in 70% (v/v) ethanol was validated (R2 > 0.999) in the 0.1–0.7 mg/mL range of zein  scCO2 environment in the batch mode for 2 h; and (3) a continuous CO2 flow of 5 g/min for 1.5 h. Finally, aerogels were obtained after depressurization at a rate of 2 bar/min. Starch aerogels were collected from the autoclave and stored in sealed containers for subsequent characterization. Starch hydrogels with 1:5, 1:3, and 1:0 zein-to-starch weight ratios were also produced following the same gelation method reported above for the sake of visual comparison of physical integrity and homogeneity of the gels.Corn starch aerogels were produced according to the following procedure. Starch aqueous dispersions of 10% ( of zein . Starch v/v) was added at the bottom of the said vessel as an additive to improve the sterilization efficacy specially towards endospores S, [Z1]S and [Z2]S scaffolds (9–12 mg) were placed in Transwells in quadruplicate with 200 µL of Opti-MEMTM. The Transwells were introduced in the wells with cells containing 800 µL of Opti-MEMTM. Positive controls of cells with 1000 µL of Opti-MEMTM and blanks of 1000 µL of Opti-MEMTM both in quadruplicate were included and treated in the same way. After 24 h of culture, the Transwells were removed, supernatants were taken and kept at −80 °C leaving 250 μL in the wells. 25 μL of WST-1 reagent were added to the wells to measure the cell viability. The plate was incubated for 2 h at 37 °C in a humidified atmosphere with 5% CO2 and then shaken thoroughly for 1 min. 110 µL were transferred in duplicates to a 96-well plate and the absorbance was measured at the wavelength of 450 nm in a microplate reader .Human bone marrow-derived mesenchymal stem cells , cell viability (1-way ANOVA), and mechanical behavior (2-way ANOVA) were performed using Statistica v8.0 software  followed by the post hoc Tukey HSD multiple comparison test.2 treatment of aerogels ensured an effective sterilization of the end nanostructured materials. Textural properties of the aerogels changed after the sterilization treatment, although the mechanical performance of the treated material was not compromised. The biocompatibility of the sterile aerogel scaffolds showed promising values (>80% cell viability) for the aerogels endowed with dual porosity. The remarkable potential of this supercritical CO2 technology is not restricted to sterilization ability purposes, but can also be exploited for the preservation of the physicochemical properties of the biomaterial to be treated, including the complex nanoarchitectures of aerogels. Overall, the herein presented processing method is compatible with the production of bio-based aerogels with dual porosity for regenerative medicine purposes. For the sake of economy of the process, the integration of supercritical CO2-based drying and sterilization methods is of interest for further studies.Sterile corn starch-based aerogels with tailor-made porosities were obtained by an innovative multi-step integrating approach. Macroporosity of 1–2 µm in starch aerogels was induced by the addition of zein, a biocompatible porogen, without involving an extra leaching step, like in other conventional practices. The design and manufacturing of the aerogels using this technological platform has clear advantages, as compared to the hitherto tested methods for the induction of well-integrated macropores in the inner mesoporous backbone of aerogels. The optimized process for scCO


Hepatic artery thrombosis is the most frequent vascular complication following orthotopic liver transplantation, and often results in biliary complications, early graft loss and death. Surgical revascularization and retransplantation are considered the mainstay of treatment. However, intraarterial endovascular therapy is an alternative that has shown low morbidity and mortality, thereby avoiding the need for retransplantation. We describe a case of orthotopic liver transplantation complicated with hepatic artery thrombosis that was successfully treated with endovascular therapy. Post-operative complications include hemorrhage, stenosis, and thrombosis at any vascular anastomosis, however, hepatic artery thrombosis (HAT) and portal vein thrombosis (PVT) are considered the most common complications.HAT and PVT interrupt adequate graft vascularization which leads to graft dysfunction, loss and even patient death, making this a serious complication requiring urgent revascularization.Surgical revascularization and urgent retransplantation are considered as the mainstay therapy, however endovascular therapy is an attractive alternative with a comparatively high success rate and low mortality and morbidity.A 39 year-old male with a past medical history of sclerosing cholangitis and hepatic cirrhosis classified as Child-Pugh C was subjected to a cadaveric whole liver transplantation. Conventional surgical technique was performed with resection of the inferior vena cava and venovenous bypass with a total cold ischemic time of 460 min. Post-operative immunosuppression therapy included tacrolimus, mycophenolate mofetil, and steroids. Anticoagulant therapy was not administered.® vascular graft .A Doppler ultrasound on post-transplant Day 2 (PTD) demonstrated absence of flow in the hepatic artery. An emergent exploratory laparotomy attributed this finding to thrombosis at the site of vascular anastomosis and an aorto-hepatic bypass was placed with a No. six ringed GORE-TEX −1, direct bilirubin: 4.74 mg dl−1) with increased liver enzymes . A hepatic ultrasound reported absence of flow in the hepatic artery at the hilum without evidence of intrahepatic arterial flow. Occlusion of the aortohepatic vascular graft was confirmed with angiography  and a 4 Fr catheter were used to access the graft and perform catheter-directed thrombolysis with recombinant tissue plasminogen activator (rtPA) 4 mg initial dose followed by 4 mg continuous infusion for 20 min  was placed, achieving adequate flow in the vascular graft and the main branches of the right hepatic artery.  was placed and expanded to 14 mm  . Thrombosis of the inferior vena cava (IVC) was suspected and a cavography was performed, confirming occlusion of the infrarenal IVC with collateral filling . A multiailable) . Controlailable) . The pat3 months after discharge, the patient developed an abscess at a previously detected site of focal hepatic necrosis, requiring percutaneous drainage with complete resolution after 3 weeks.2,3 It is defined as a thrombotic occlusion of the hepatic artery and is classified as early or late depending on time of presentation following liver transplantation. Early HAT occurs within 30 days and is associated with a rapid clinical deterioration, a high rate of graft loss and increased mortality rates. Late HAT occurs after 30 days post-transplantation and has a relatively mild clinical course.4 Because the hepatic artery is the only route by which oxygenated blood is supplied to the liver, its obstruction results in parenchymal and biliary ischemia. Clinically, its presentation varies from slight signs of parenchymal involvement to fulminating hepatic failure.HAT is the most common and severe vascular complication following orthotopic hepatic transplantation, accounting for approximately 50% of vascular complications and with reported mortality as high as 75%.3 Clinical markers that may indicate early HAT include fever, leukocytosis, elevation of hepatic enzymes, hiperbilirubinemia, and shock. Other patterns that may also suggest HAT include fulminant hepatic failure, late-onset biliary leakage, and recurrent bacteremia.5 Doppler ultrasound within the first 3 days post-transplantation provides the advantage of diagnosis of HAT before clinical manifestations become apparent.3A determining factor that limits hepatic injury and graft loss is the early detection of arterial complications by means of Doppler ultrasound of the liver and angiography.6 Urgent endovascular revascularization therefore plays an important role in the management of HAT, potentially avoiding the need for retransplantation in cases where a diagnosis is made before signs and symptoms of graft dysfunction become apparent.2 Sheiner et al report a revascularization survival rate of 40 and 82% in symptomatic and asymptomatic patients, respectively.7Three treatment options have been described for HAT: surgical revascularization, urgent retransplantation and endovascular revascularization. Retransplation is considered the first-line therapy, however, it often carries a higher mortality rate and is limited by a shortage of donors.et al in 1989.8 It is thought that thrombolysis is most effective in “fresh” thrombi due to a higher water content and a matrix relatively poor in fibrin. Literature on this particular topic varies greatly, some recommending thrombolysis as early as 4 h and others as late as 120 days post-transplantation. There are no current guidelines regarding the therapeutic window for thrombolysis. Nevertheless, the general consensus is that it should not be attempted more than 3 months post-transplantation.2Intra-arterial thrombolysis for HAT was first described by Hidalgo e.g. kinks, twist, dissection or stenosis at the site of anastomosis). Angioplasty and stent placement after intraarterial thrombolysis have become a solution with more favorable results.9,10 It is important to mention that multiple points of stenosis as well as HAT in pediatric patients are not considered absolute contraindications for thrombolysis and angioplasty, particularly if retransplantation is not an option.Hepatic-artery thrombolysis is considered a safe treatment, with the most common and severe complication being hemorrhage reported in approximately 20% of patients. The main pitfall of thrombolysis is short-term recurrence of HAT if the conditions that favored its formation are not resolved (11 It is most often related to surgical technique and generally occurs within the first month after transplantation. Without prompt diagnosis and therapeutic intervention, it is associated with high morbidity, mortality and graft failure. There are several reports of successful management of thrombosis of the IVC with thrombolysis and stent placement.12 Surgical repair may be unavoidable in cases of restenosis or kinking of the graft due to size mismatch between the donor and recipient.Our patient also presented with thrombosis of the IVC, a rare complication estimated to occur in 1–2% of transplants.HAT is a serious complication of liver transplantation and early detection is crucial to preserve function and viability of the graft and improve patient survival. Post-operative hepatic Doppler ultrasound is an important tool in early diagnosis, although angiography is currently the gold standard in the detection of this complication with the added benefit of permitting endovascular therapeutic options. Catheter directed thrombolysis is safe and effective, although restenosis is common if the predisposing factor is not corrected. However, when combined with post-thrombolysis balloon angioplasty and stent placement, therapeutic results and patient outcome may improve. Although the ideal treatment of symptomatic patients and those with severe graft dysfunction is urgent retransplantation, the shortage of donor livers makes endovascular therapy an attractive therapeutic option to save the graft and avoid retransplantation or facilitate it in an elective setting.Early detection of hepatic artery thrombosis is critical to conserve graft vitality.Doppler ultrasound assessment must be done by experienced sonographers and in case of doubt, an angiography or angiotomography must be performed.Thrombolysis of the hepatic artery is safe and effective.After thrombolysis, balloon angioplasty with or without stent placement may be needed.


Comparative study on micro-deep hole drilling by picosecond ultra-short pulse laser in four metals, including copper, aluminum alloy, titanium alloy, and nickel alloy, was presented. Destructive testing was performed to measure the depth, shape, and side-wall morphology of micro-deep holes in this study. Diameters and depths of micro-deep holes in four metals ablated using the same processing parameters were compared. The multiple thresholds of metals had been calculated. Relationships between hole dimensions and multiple thresholds  and physical properties  of the four metals are examined. Furthermore, the surface and side-wall morphologies of the micro-deep holes in four metals were demonstrated. The influence mechanisms, especially the side-wall morphology, were discussed, such as the thresholds, conical emission, self-cleaning effect, physical properties of metals, the energy transmission, the plasma effect, thermochemical reaction, and so on. Ultrashort pulsed laser micro-hole ablation offers lots of advantages, including breaking through the diffraction limit so the low-micron even nanometer holes could be expected ,2, proceA few studies on the side-wall morphology of micro-deep hole have been performed in metals, however. Two main issues are, first, holes cannot be detected the real-time during the ablation process because metals are not transparent; thus, measurements must be performed afterward. Second, the depth and side-wall morphology of micro-deep holes cannot be directly measured using available methods, such as laser scanning confocal microscopy (LSCM), atomic force microscopy (AFM), and stylus profilometry (SP). Effective measurement methods are destructive and require metal samples first to be ground and polished and subsequently imaged. In this way, the side profile and side-wall morphology of drilled holes have been obtained by scanning electron microscopy (SEM). For example, Li et al.  successf3/J), Spiro et al. investigated picosecond pulsed laser hole drilling with three different wavelengths in five metals: aluminum, nickel, stainless steel, molybdenum, and tungsten [Furthermore, the comparative study on multiple metals drilling is less. For example, Campbell et al. reported hole ablation in aluminum, copper, stainless steel, and titanium, but only the hole depth was studied, and they were less than 25 µm . By comptungsten . In anottungsten .Overall, ultrashort pulsed laser micro-hole ablation is generally concerned about the dimension and the surface morphology around the hole periphery, but less about the side-wall morphology of micro-deep hole based on the limitation of the detection. However, the side-wall morphology of the micro-deep hole in metals ablated by ultrashort pulsed laser is very important. For example, the difference in the side-wall morphology directly leads to the difference in the laser effect, which further affects the distribution state of energy, that is, the state of material removal. For the practical application, the side-wall morphology of hole determines the anti-corrosion characteristics, adhesion characteristics, and the crack generation mechanism, etc. In this paper, a comparative study of micro-deep holes fabricated by ultra-short pulsed laser percussion drilling in four metals, including Cu, Al alloy, Ti alloy, and an Ni alloy, is presented. Multiple thresholds were calculated for the metals, and the relationships between hole dimensions and the thresholds were determined. In addition, the physical properties of the metals are discussed. The surface and side-wall morphologies of micro-deep holes in the four different metals are compared.The laser source used in the experiments was a neodymium-vanadate  laser with a pulse duration of 10 ps. The laser wavelength was 532 nm, and the laser beam was linearly polarized with a repetition rate of 1 kHz. A laser beam with a radius of about 19 µm was directly focused on the surface of samples, including Cu (purity 99.9 wt.%), Al alloy , Ti alloy (Ti6Al4V), and Ni alloy (Inconel 718), and focused using an F-theta lens with a focal distance of 150 mm. In addition, the maximum laser power for a wavelength of 532 nm was approximately 135 mW. Accordingly, the maximum laser energy was 135 µJ when combined with a repetition rate of 1 kHz, and the laser energy had been adjusted from 2 µJ to 135 µJ by the attenuator. Samples were placed on a 3D motorized translation stage , allowing accurate high-precision control of the laser position. Moreover, an accurate imaging system with a CCD (charge-coupled device) camera was used, enabling high-resolution visualization of the ablation zone on sample surfaces. A schematic illustration of the experimental setup with the ultra-short pulsed laser is shown in Experiments were performed under ambient conditions. Afterward, the surface morphologies of the holes were observed by SEM , and the diameters of the holes were measured on the surface of SEM micrographs. The single hole diameter was obtained by averaging the maximum and minimum values. At least five holes were measured for the same processing parameters, and then the average was figured up. Depths of the shallow holes were measured by LSCM . Destructive testing was used for holes with depths outside the LSCM measurement range, as shown in Differences in hole dimensions in the four metals are illustrated in Differences in the hole dimensions between the four metals illustrated in Herein, the ablation of the Al alloy is taken as an example, and on model .A comparison of the average ablation threshold No corresponding relationships were found between any of the thresholds and hole diameter. The opposite trend can be observed between the ablation threshold ld value . The samCharacteristics of metals, such as heat capacity, melting temperature, optical penetration depth, and absorptivity of the material, as shown in Comparing Hole surface morphologies are shown in Overall, self-cleaning effects were observed for Al alloy, Ti alloy, and Ni alloy during ultra-short laser pulsed ablation, suggesting that subsequent pulses remove molten material from around the hole surface, thereby obtaining micro-deep holes with high-quality surface morphologies . FurtherPhysical properties also influence hole surface morphology, such as those presented in Compared to Al alloy, the higher thermal conductivity and melting temperature of Cu suggest that it will have a smaller thermal threshold, and the optical penetration depth of Cu is deeper, causing laser energy to deliver into the material easily. Therefore, less molten material was found around the ablated holes in Cu than in the Al alloy. Since Ni alloy has a higher thermal conductivity and lower melting temperature, its thermal threshold will be larger than the Ti alloy, leading to more molten material around the holes in Ni alloy. However, these observations only apply to ablation with fewer than several thousand pulses of Ti and Ni alloys since the hole surface morphology is determined by the self-cleaning effect when the number of pulses is high.At present, the only method for measuring the side-wall morphology of micro-deep holes is first grinding and polishing samples and then performing SEM, as shown in Side-wall surface morphology appears smooth near the inlet, but as the hole depth increases, side-wall surfaces of holes become rougher. Ripples, microcracks, ravines, precipitation, recast layers, and a fish-scale structure are characteristic of the side-wall surface. For example, the fish-scale structure was observed on the lower side-wall surface in Al alloy, Ti alloy, and Ni alloy, as shown in Microcracks worsen the mechanical properties of metal; however, this varies for different metals. Microcracks that formed in the laser-ablated Cu were perpendicular to the direction of the hole depth, and they are width and depth shown in For the formation mechanism of the side-wall morphology of hole drilled by an ultrashort pulsed laser, it mainly contains four aspects, as shown in High-intensity laser would ionize air and material particles to form atmospheric plasmas and material plasmas . PlasmasThis paper presented a comparative study on micro-deep holes drilling by picosecond ultra-short pulse laser in four metals: Cu, Al alloy, Ti alloy, and Ni alloy. Different holes diameters were obtained in the metals as the laser energy was increased. The deepest hole was observed in the Ti alloy, followed by Cu, then Al alloy, and finally, Ni alloy. The average ablation thresholds, ablation thresholds, and thermal thresholds of four metals had been calculated. The influence of multiple thresholds and physical characteristics of four metals on the dimensions of ablated holes were discussed. In the experiments, it has been found that there was the opposite trend between the ablation thresholds and hole depths. When the heat capacity and melting temperature of metal were high, or the optical penetration depth was small, the ablated holes were shallow. When there were the low heat capacity and the high absorbance, the holes were deep.Each metal exhibited unique morphological characteristics. For example, holes surfaces in Cu have short, and deep ravine structures along the direction of the holes depth, and molten material are distributed throughout the hole. In contrast, molten material builds up around the holes surface in Al alloy during ultra-short pulsed laser ablation, the self-cleaning properties of Al, Ti, and Ni alloys resulted in micro-deep holes with high-quality surfaces. Moreover, all of the holes were cone-shaped, and the characteristic morphologies on the surfaces of the side walls contained ripples, microcracks, ravines, fish-scale structures, precipitation, and recast layers. Some differences in morphology were also observed between the different metals, such as the direction and scale of microcracks. Furthermore, possible mechanisms responsible for the differences among metals after ablation were discussed, such as the multiple thresholds, conical emission, self-cleaning effect, physical properties of metals, and so on. Besides, the influence mechanism of hole side-wall morphology also had been demonstrated.


Machine-type communication (MTC) is an emerging communication trend where intelligent machines are capable of communicating with each other without human intervention. Mobile cellular networks, with their wide range, high data rates, and continuously decreasing costs, offer a good infrastructure for implementing them. However, power consumption is a great issue, which has recently been addressed by 3GPP (3rd Generation Partnership Project) by defining power-saving mechanisms. In this paper, we address the problem of modeling these power-saving mechanisms. Currently existing modeling schemes do not consider the full range of states in the discontinuous reception (DRX) mechanism in LTE-A networks. We propose a semi-Markov based analytical model, which closes this gap and shows very good results in terms of predicting performance evaluation metrics, such as the power-saving factor and wake-up latency of MTC devices compared to simulation experiments. Furthermore, we offer an evaluation of the DRX parameters and their impact on power consumption of MTC devices. Machine-type communication (MTC), which is also termed as machine-to-machine M2M), is realized as a communication style where two or more devices exchange data with each other or with a set of servers, mainly without human assistance. Therefore, MTC is also considered one of the potential enablers for supporting the Internet-of-Things (IoT) paradigm in the future. Moreover, MTC covers a vast range of applications which include intelligent transportation systems, security, smart metering and monitoring, logistical processes, warehouse management, e-heath monitoring, wildlife management, home automation, and many more ,2.M, is reaUnlike those of traditional human-type communication (HTC), the features of MTC traffic are quite different from the legacy mobile traffic, such as voice and video in terms of the number of devices, their QoS requirements, device or chipset costs, and power consumption . For insSeveral MTC applications, such as e-health, remote management and control, mobile computing, gaming, industrial wireless automation, and wildlife management, are growing vastly in popularity and receiving attention from service providers as well as end-consumers . HoweverIn order to estimate the power consumption of an MTC device in an LTE/LTE-A network, several efforts were made in the literature to analyze the performance of a DRX mechanism through analytical modeling. As a result, the power consumption of LTE/LTE-A devices was approximated, which can ultimately provide some insights regarding the expected operating time of the device. In the case of MTC devices, most of the existing power consumption models on DRX mechanism for regular HTC traffic may also be used for MTC applications generating regular traffic patterns. However, limited research efforts have been made to model the power consumption behavior of event-based MTC traffic. This is due to the distinct features of event-based MTC traffic, which make it quite crucial to analyze the characteristics of the DRX mechanism for estimating power consumption more precisely compared to its counterpart regular traffic . One of The remainder of the paper is organized as follows. In an LTE-A network, when a device is powered on, it usually has two radio resource control (RRC) states, which include RRC_Connected and RRC_Idle. The transition from RRC_Connected to RRC_Idle and vice versa depends on the packet activity. An Inactivity timer is triggered to push the device from the RRC_Connected to the RRC_Idle state. When there is no traffic activity until the expiry of the inactivity timer, the device transitions from the RRC_Connected to the RRC_Idle state. Moreover, the RRC inactivity timer is reset with any uplink or downlink data activity .In an LTE-A network, a device may be configured with a DRX mechanism by RRC in both connected and idle states. However, the functionality and configuration parameters in different states also vary. Since data activity mainly occurs in a connected state, the main target modes are in the active and DRX states. In addition to the RRC Inactivity timer, the network also triggers a DRX inactivity timer to move the device from active mode to DRX mode. When there is no packet activity, the device stays connected but transitions to the DRX mode. Furthermore, the DRX inactivity timer is reset when there is a packet activity . In an LN consecutive short DRX cycles, the device enters the long DRX cycle. If the short DRX cycle is not configured, the device enters the long DRX cycle directly. However, the short DRX cycle is important to be configured for delay-sensitive traffic as it reduces the overall latency and the wake-up delay. A brief description of various DRX parameters is provided in In an LTE-A network, the DRX mode is configured by several parameters and timers, such as the on duration timer RX cycle . After NIn the literature, several efforts were made to study the DRX mechanism in an LTE-A network. Moreover, these efforts were made in order to study the DRX mechanism for both MTC and HTC traffic by taking into account various parameters of DRX. For instance, the authors of  studied In addition to the existing models given in In this paper, a semi-Markov chain model is proposed for modeling a DRX mechanism in MTC, which is different from the existing models as it not only takes into account the probability of packet arrivals during the tail time but also considers power consumption variations during active mode based on the system and context parameters in order to better estimate the power consumption in MTC applications. The short DRX cycle is proposed which can be used for delay-sensitive HTC and MTC traffic . A summaIn the system model, we first describe the power consumption variations during the active and non-active modes. Afterwards, the proposed semi-Markov chain model is comprehensively explained by considering numerous DRX parameters in an LTE-A network. The list of the used symbols for modeling the DRX mechanism is provided in According to Reference , the poweference . In addiBased on Equation , the empLow: In this state, the transmit power control (TPC) algorithm of LTE-A described in Reference  adjusts er state . Thus, tHigh: If the overall transmission power Max: If the TPC algorithm can no longer achieve the target SNR by compensating for the path loss, the device enters the max power state, in which the device power consumption has reached the maximum value. Therefore, the average device power consumption for the max power state is selected to be In the non-active state, the device is not in a continuous reception mode. However, it can be in on duration, short sleep, long sleep, tail, or RRC connection state. Moreover, the power consumption is reduced to zero when the device is in short/long sleep state. However, in active state, the device is in a continuous reception mode, where it can transfer data. Since the power consumption curves were observed to be linear for all tested devices in Reference , the folt follows an exponential distribution with a common mean value equal to RRC_Connected.me state .N short sleep states within N short DRX cycles. The short sleep mode is proposed particularly for delay-sensitive MTC traffic.N on duration periods within N short DRX cycles and therefore correspond to N short sleep states.Since MTC covers a wide area of applications ranging from smart metering to emergency alerting, therefore, its traffic characteristics also vary. For instance, MTC devices mainly generate a huge traffic volume by accessing the network on a large scale. Therefore, the devices may attempt that several times to perform packet activities. Considering the random generation of MTC traffic, the input MTC traffic is modeled according to the Poisson process with a packet arrival rate of N) are specified. In addition, the state transition probability from a state j to a state k in the proposed model is denoted by In the proposed semi-Markov model, parameters such as the DRX inactivity timer In state quations , respectquations  and 9)::S5, the N DRX short cycles, the device enters the long cycle. The respective transition probabilities are given in Equations (quations –13):∏=πlth subframe of the on duration period with the probability of Let On the other hand, when the device is within the on duration state of the long DRX cycle, there are also three cases. In the first case, the packet arrives after the expiry of the on duration with the probability Additionally, when the device is within the active states, there are two cases. In the first case, the packet arrives after the expiry of the DRX inactivity timer with the probability In this paper, we evaluate the performance of the proposed semi-Markov model based on metrics such as power-saving factor Equation , whereasquations , 17) an an(PS) aquations .(20)PS=d, which is defined as the time interval between the packet arrival and departure, is usually experienced in the case of the RRC connection state and sleep modes. Furthermore, the packet arrival over the short DRX cycle and long DRX cycle follows, on average, a uniform distribution in the case of the Poisson arrival process. In the corresponding short and long DRX sleep states, the latency of short and long sleep modes can be interpreted as d can be calculated according to Equation (The wake-up latency Equation :(21)d=TIn order to validate the semi-Markov-based model proposed for analyzing a DRX mechanism in an LTE-A network, simulations were also performed using a simulation model developed in MATLAB. In the simulations, the packet arrival process was modeled according to the Poisson distribution. Thus, the packet inter-arrival time followed exponential distribution with common mean eference  based onIn this subsection, the results obtained from the proposed analytical model for analyzing a DRX mechanism are validated through simulation results. For this reason, the performance metrics of the DRX mechanism, such as the power-saving factor and wake-up latency, were also determined via simulations by modeling all the DRX parameters.d vary according to the different values of packet inter-arrival time d also increases for the increasing packet inter-arrival time, as depicted in d. Results showed that the power-saving factor decreases gradually as the value of the DRX inactivity timer increases, see Similarly, d. d decreases by approximately 11% for the increasing values of d significantly increases for the larger values of the long cycle timer. For instance, when the long cycle timer value is raised to 2560 ms, the wake-up latency increases by 76%.In From the aforementioned results, we found that the packet inter-arrival time has the highest impact on the power-saving factor as In this paper, we proposed a semi-Markov chain model for analyzing the DRX mechanism in cellular MTC networks. The proposed analytical model was verified through simulation results. The performance metrics, such as the power-saving factor and wake-up Latency, were modeled with high precision and can be used for further research in the area of power saving for MTC communications, e.g., in Reference .We further investigated the influence of various DRX-related parameters on the performance of the power-saving factor and wake-up latency. Our results showed that the packet inter-arrival time and the tail time influenced the In the future, the proposed semi-Markov model can also be adapted for modeling of the battery life time of a device. Consequently, the operating time of a device can be estimated with high precision.


Pseudoaneurysms after visceral transplantation represent a significant risk to patients. We report the successful treatment of three transplant  artery anastomotic pseudoaneurysms using physician-modified fenestrated endovascular stent grafts. In all cases, surgical repair was considered high risk and would have compromised the arterial supply to the graft. The endovascular approach in all cases obviated the need for surgical intervention and maintained graft arterial supply. Pseudoaneurysms of the arterial anastomosis to visceral transplants are rare. They are more common in pancreas transplants because of sepsis and damage from pancreatic leaks with a reported incidence of up to 8% . Their tA stent graft for the treatment of a visceral transplant pseudoaneurysm is an off-label use that requires specific preoperative consent. Computed tomography (CT) angiographic imaging is essential for planning, and device modification should take place in a sterile environment. We recommend that it is done immediately prior to implant, in the same theatre, to minimise the risk of contamination through handling. The choice of stent graft device is pragmatic, determined by local availability and the size of artery to which the transplant is anastomosed. Thoracic aortic, abdominal aortic and iliac devices can be used.The graft design is planned from the CT imaging in a similar manner to planning a standard complex EVAR. After a suitable donor stent graft has been identified, the rotational orientation and the distance from the proximal edge of the stent graft for the centre point of the fenestration should be measured from multi-planar reconstruction of the CT scan. 1-mm slices are generally the maximum slice thickness that we would consider sensible. The fenestration size is determined by the size of the transplant vessel and should be roughly equal.The graft is typically deployed on a sterile field Fig. A, and thMetal struts from the skeleton of the stent graft should be avoided, and in most cases it is possible to position a single fenestration away from the struts; however, in other more complex designs, we have successfully removed struts with wire cutters, carefully suturing over the cut ends.Existing radiopaque markers are useful to orientate the graft, and one marker on the proximal edge should be used to mark either zero degrees or the fenestration angle, depending on user preference. If no markers are correctly positioned, they can be removed and re-sutured onto a more useful position.Polyester donor stent grafts can be easily shortened with an Accutemp low-temperature cautery pen . This pen is also used to create the fenestration Fig. B. The feDeployment is similar to a standard fenestrated EVAR. Accurate positioning of the fenestration during initial deployment is the key, particularly as there is only limited ability to move the main stent graft when it is uncovered. We recommend visualising the ostium of the target (transplant) artery in the two orthogonal planes which can be determined from the CT scan. The fenestration should be positioned adjacent to the target vessel, but the gooseneck snare is always deformed within the delivery system and does not give a reliable indication of rotational alignment, so the radio-opaque markers on the proximal edge of the stent graft should be used to finesse the rotation as the graft is initially uncovered. It can be helpful to position a catheter or guidewire within the target vessel to aid alignment.Once the main graft is deployed, the fenestration should be catheterised from within the graft in a standard manner. A guidewire is passed into target vessel, followed by a long vascular sheath. An appropriate balloon mounted covered stent (e.g. Atrium Advanta V12) , sized to the transplant artery, is then deployed across the fenestration into the target vessel. The covered stent is over-dilated, typically to 8 to 12 mm within the fenestration to seal the fenestration and prevent migration.The technique described herein was used in three transplant cases: pancreas, liver and kidney (summarised in Table Visceral transplant anastomotic pseudoaneurysm formation is rare but a life- and transplant organ-threatening complication. They have a multi-factorial aetiology including surgical technique, infection, post-operative anastomotic/bile leak and pancreatitis , 4. ClinEndovascular management can be considered an alternative to open surgery in the management of transplant arterial pseudoaneurysms; however, its technical validity has been questioned . Global The use of physician-modified fenestrated stent grafts has been described in the emergent treatment of complex aortic aneurysms with favourable clinical outcomes –22. ThisThe aetiology of pseudoaneurysm formation in the cases described remains uncertain, but endovascular management has obviated the need for surgery thus far and maintained graft vascular supply. Some of these pseudoaneurysms developed in the presence of infection. This can be considered a contra-indication to endovascular repair, but there are reports of successful endovascular stent grafting in the presence of infection, either as a bridge to definitive open repair or as a definitive solution itself –26. In tTransplant pseudoaneurysms are a difficult to manage and high-risk patient group. The cases presented here using physician-modified fenestrated stent grafts successfully treated the pseudoaneurysms and maintained graft vascular supply. This technique is technically demanding but promising. Longer-term follow-up is needed to better understand this technique’s true clinical value.


Our previous studies demonstrated that intrinsic aortic smooth muscle cell (VSMC) stiffening plays a pivotal role in aortic stiffening in aging and hypertension. However, the underlying molecular mechanisms remain largely unknown. We here hypothesized that Rho kinase (ROCK) acts as a novel mediator that regulates intrinsic VSMC mechanical properties through the serum response factor (SRF)/myocardin pathway and consequently regulates aortic stiffness and blood pressure in hypertension.in vitro.Four-month old male spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats were studied. Aortic stiffness was measured by echography. Intrinsic mechanical properties of VSMCs were measured by atomic force microscopy (AFM) in vitro and aorta wall stiffness in vivo.Compared to WKY rats, SHR showed a significant increase in aortic stiffness and blood pressure, which is accompanied by a remarkable cell stiffening and ROCK activation in thoracic aortic (TA) VSMCs. Theses alterations in SHR were abolished by Y-27632, a specific inhibitor of ROCK. Additionally, boosted filamentous/globular actin ratio was detected in TA VSMCs from SHRversus WKY rats, resulting in an up-regulation of SRF and myocardin expression and its downstream stiffness-associated genes including α-smooth muscle actin, SM22, smoothelin and myosin heavy chain 11. Reciprocally, these alterations in SHR TA VSMCs were also suppressed by Y-27632. Furthermore, a specific inhibitor of SRF/myocardin, CCG-100602, showed a similar effect to Y-27632 in SHR in both TA VSMCs stiffness ROCK is a novel mediator modulating aortic VSMC stiffness through SRF/myocardin signaling which offers a therapeutic target to reduce aortic stiffening in hypertension. Hypertension is a highly age-related disease and affects more than 1 billion people worldwide. The progressive increase in blood pressure (BP) with age is characterized by a greater increase in isolated systolic hypertension, a larger elevation in systolic blood pressure (SBP) than diastolic blood pressure (DBP), leading to an accelerating rise in pulse pressure (PP) after 50 years . AlthougRho kinase  is a serine/threonine protein kinase that contains an N-terminal catalytic kinase domain, which has been identified as one of the effector of the small GTP-binding protein Rho. Although accumulating evidences have demonstrated that the ROCK pathway plays a crucial role in the pathogenesis of hypertension , 11, 12,in vivo drug treatments, Y-27632 , CCG-100602  or vehicle control  were continuously administered for 2 weeks by Alzet osmotic minipumps , implanted subcutaneously in rats under anesthesia with 2% isoflurane  [Adult (4 month-old) male spontaneously hypertensive rats (SHR) and normotensive control Wistar-Kyoto (WKY) rats  were studied as described previously . All aniSystemic systolic and diastolic blood pressures (SBP and DBP) were measured in conscious animals by restraint tail cuff every two days for 2 weeks using the CODA system  as described previously . Aortic Hemodynamic assessment was performed by doppler ultrasound echocardiography under anesthesia with 2% isoflurane  simultaneously with the non-invasive tail-cuff (baseline and 1 week) or invasive catheter (2 week) BP measurement. The following measurements were performed: heart rate (HR), cardiac output (CO), diastolic diameter of the thoracic aorta (D), systolic minus diastolic diameter change (ΔD). Regional aortic stiffness was evaluated by arterial compliance (C) which is the absolute change in diameter (ΔD) for a given pressure step (PP) (C =ΔD/PP) and arterial strain (ΔD/D) .Rats were euthanized with carbon dioxide inhalation and artery tissues were rapidly collected. Primary VSMCs were isolated from aorta and arteries of SHR and WKY rats and serially cultured for up to three to four passages as described previously , 20. VSMap) was determined using Hertz contact analysis for a cone to model the indentation force curve. The effects of drug interventions on VSMC stiffness were also assessed. Isolated VSMCs in subconfluent monolayer culture were treated for 24 hours with Y-27632 (22.5 to 2250 nmol/L), or CCG-100602 (1.12 μmol/L) or vehicle control (DMSO) prior to AFM indentation testing as described above.Single-cell micromechanical measurements were performed using a biological AFM system  with a silicon nitride AFM probe  with a pyramidal tip (radius 40 nm). As we recently described , two nanRNA was extracted from isolated VSMCs by using Quick-RNA MiniPrep kit  according to the manufacturer’s instructions. Quantitative real-time PCR was performed on a CFX96 Touch™ Real-Time PCR Detection System by using iTaq™ Universal SYBR® Green Supermix  according to the manufacturer’s instructions. All real-time PCRs were performed in triplicate as described in our previous study , 21.Total protein was extracted from VSMCs using cell extraction buffer  as described previously , 10, 22.Activity of ROCK was measured by using a ROCK activity assay kit  according to the manufacturer’s instructions.VSMCs were fixed with 4% paraformaldehyde in PBS, permeabilized in 0.2% Triton X-100 and then stained with primary α-SMA antibody (Sigma) at a dilution of 1:100 using standard immunofluorescence staining techniques as described previously , 24.in vivo assay kit  [The F/G-actin ratio in VSMCs was determined by Western blotting using the G-actin/F-actin 037, CO)  and by i037, CO) .Results are presented as the mean ± SEM for the number of samples indicated in the figure legends. One-way ANOVA or two-way ANOVA was used to test effects of group (WKY vs. SHR), region (TA vs. RA), and drug intervention. Student-Newman-Keuls post hoc correction was applied for multiple pairwise comparisons. A value of p<0.05 was considered statistically significant.th day of treatment, while it modestly reduced SBP and DBP in WKY rats at the end of day 14 and 12 of the treatment, respectively ; After washing away Y-27632 for 30 minutes (step 4), the VSMC elastic modulus began to return back toward baseline (step 5). This data indicated that the reduction of VSMC stiffness specifically relied on the inhibition of ROCK by Y-27632 (ap) was observed with the concentrations of Y-27632 from 22.5 nM to 2.25 μM (ap of TA VSMCs was significantly higher in SHR (7.1± 0.1 kPa) vs. WKY rats (5.1 ± 0.1 kPa) (P<0.01) under vehicle control conditions. Treatment with Y-27632 reduced the TA VSMC stiffness in both SHR and WKY compared with the respective vehicle controls (P<0.01 vs. vehicle). These findings confirmed the temporal measurements.We then measured the alteration of intrinsic stiffness of individual VSMCs by using AFM. As shown in  Y-27632 . To exam 2.25 μM . FurtherTo determine the role of ROCK in the regulation of intrinsic TA VSMC stiffness, two complementary approaches were used: first, we tested whether ROCK activity was specifically increased in aortic VSMCs, and second, we tested whether Y-27632 inhibited ROCK activity selectively in aortic VSMCs. Our previous studies showed that stiffness was significantly increased in VSMCs isolated from TA but not in RA from the same SHR rat , this reNext we explored the signaling pathway involved in the regulation of VSMC stiffness by ROCK in hypertension. We first tested the content of filamentous (F) and globular (G) actin in VSMCs treated with Y-27632 or vehicle, using western blot and specific immunostaining. Compared to WKY rats, the F/G-actin ratio was strikingly increased by 2.2-fold in vehicle-treated TA VSMCs from SHR, which was almost completely blocked by treatment with Y-27632 . This obP<0.01); these elevated gene expression levels were rectified by treatment with Y-27632 , myosin heavy chain 11 (MYH11), smooth muscle 22 (SM22) and smoothelin (SMTN) in TA VSMCs from SHR compared to WKY rats (all  Y-27632 . Western Y-27632 . These r Y-27632 .Our data presented above indicated that SRF/myocardin acts as a linker between ROCK and VSMC stiffness. To test whether SRF/myocardin are necessary for ROCK mediated VSMC stiffness, a specific inhibitor of SRF/myocardin interaction, CCG-100602, was used to block the SRF/myocardin interaction. We found that treatment with CCG-100602 did not change ROCK activation in TA VSMCs from SHR compared to vehicle, indicating that CCG-100602 targets the downstream pathway of ROCK . Howeverin vivo, both SHR and WKY rats were administered with CCG-100602 or vehicle for 2 weeks. Arterial compliance and strain were measured using Doppler ultrasound echocardiography. As shown in in vitro, CCG-100602 has no significant effects on aortic wall stiffness in WKY rats. Taken together, inhibition of SRF/myocardin can ameliorate the VSMC stiffness led by activated ROCK.To test whether the reduction of VSMC stiffness by the inhibition of SRF/myocardin with CCG-100602 restrained the aortic stiffness Aortic stiffening is a hallmark of aging. Emerging evidence has been demonstrated that increased aortic stiffness is not only a fundamental manifestation of vascular aging, but also an independent predictors for incident hypertension . It has Numerous studies have shown that abnormalities in ROCK activity play an important role in cardiovascular disease and especially hypertension , 12. TheMoreover, our results indicate that reduction of VSMC stiffness is a potential strategy for the reduction of aortic stiffening. Although it has been widely accepted that aortic remodeling is an important contributor to aortic stiffening in aged or hypertensive patients , 35, ourFurthermore, our observations also indicated that reduction of aortic stiffening is a promising therapeutic strategy in the treatment of hypertension, particularly in the control of SBP. Despite increasing evidence supporting the causative role of aortic stiffness in the development of hypertension, drugs that directly target aortic stiffness remain limited. Data from the present study showed that inhibition of ROCK signaling by chronic Y-27632 treatment not only reduced DBP, but also caused an even greater reduction of SBP and PP in SHR. This disproportionate reduction in SBP and PP in our model is consistent with a reduction of aortic stiffness by Y-27632. Moreover, we observed that Y-27632 significantly reduced several indices of aortic stiffness, which preceded the reduction of blood pressure. This observation further supports the hypothesis that the correction of aortic stiffening is responsible for the reduction of SBP in SHR by Y-27632. These findings strongly suggested that pharmaceutical targeting of aortic stiffness correction might serve as a preventative strategy for the development of hypertension and its attendant complications.In addition, we identified for the first time that SRF/myocardin acts downstream of ROCK signaling and plays a central role mediating VSMC stiffness in SHR TA. ROCK has been implicated in the pathogenesis of cardiovascular disease, in part by promoting ROS production, inflammation, endothelial cell damage, and VSMC contraction and proliferation , 36, 37.in vitro and further decreased aortic stiffness in vivo without changing the total collagen deposition [To further determine the necessary mediating role of SRF/myocardin in VSMC stiffening, a specific inhibitor of SRF/myocardin, CCG-100602 was used to block their effects. Our data showed that inhibition of SRF/myocardin by CCG-100602 significantly decreased the VSMC stiffening in SHR TA position , 44. ThiIn summary, as illustrated in


Harmonia axyridis that raised high interest in insect biotechnology in recent years. We observed remarkably pleiotropic effects of harmonine on physiological, cellular, and molecular processes in adult male and female Schistosoma mansoni at concentrations as low as 5 μM in vitro. This included tegumental damage, gut dilatation, dysplasia of gonads, a complete stop of egg production at 10 μM, and increased production of abnormally shaped eggs at 5 μM. Motility was reduced with an EC50 of 8.8 μM and lethal effects occurred at 10–20 μM within 3 days of culture. Enzyme inhibition assays revealed acetylcholinesterase (AChE) as one potential target of harmonine. To assess possible effects on stem cells, which represent attractive anthelminthic targets, we developed a novel in silico 3D reconstruction of gonads based on confocal laser scanning microscopy of worms after EdU incorporation to allow for quantification of proliferating stem cells per organ. Harmonine significantly reduced the number of proliferating stem cells in testes, ovaries, and also the number of proliferating parenchymal neoblasts. This was further supported by a downregulated expression of the stem cell markers nanos-1 and nanos-2 in harmonine-treated worms revealed by quantitative real-time PCR. Our data demonstrate a multifaceted antischistosomal activity of the lady beetle-derived compound harmonine, and suggest AChE and stem cell genes as possible targets. Harmonine is the first animal-derived alkaloid detected to have antischistosomal capacity. This study highlights the potential of exploiting insects as a source for the discovery of anthelminthics.Natural products have moved into the spotlight as possible sources for new drugs in the treatment of helminth infections including schistosomiasis. Surprisingly, insect-derived compounds have largely been neglected so far in the search for novel anthelminthics, despite the generally recognized high potential of insect biotechnology for drug discovery. This motivated us to assess the antischistosomal capacity of harmonine, an antimicrobial alkaloid from the harlequin ladybird  Harmonia axyridis raised high interest being a rich source of antimicrobial compounds such as the alkaloid harmonine. Harmonine is thought to act as a chemical weapon keeping otherwise detrimental microsporidia in the beetle under control. Testing the antiparasitic potential of harmonine against adult Schistosoma mansoni, one of the most harmful helminths worldwide, resulted in multifaceted negative effects. The compound damaged tissues essential for survival and reproduction of schistosomes  and also affected stem-cell proliferation. Furthermore, we obtained first evidence for acetylcholinesterase as one potential molecular target, which was partially inhibited by harmonine. This is the first time to proof a direct effect of a defined insect-derived compound on a helminth parasite, a finding that will encourage further studies to explore insects as sources of novel anthelminthics.Natural compounds represent one of the richest sources for the discovery of new active compounds against diseases such as cancer or infections, including helminth infections that cause the highest disease burden in tropical countries. Surprisingly, insects have been almost completely neglected with respect to anthelminthics discovery although they represent the most species-rich class of animals known on earth, producing a wide spectrum of compounds with biological activities. In insect biotechnology, the harlequin ladybird  Natural compounds represent one of the richest sources for the discovery of new active compounds against cancer, infections, or other threats to human health. From 1981 to 2010, 33% of approved drugs represented natural compounds and derivatives, mostly from plants, algae, and fungi .Harmonia axyridis, which is also known as Asian ladybird or Multicolored ladybird, represents an outstanding example in this regard . Reactions were performed in 96-well plates (206 μl/well) and absorption changes at 410 nm were recorded for 3 min; the initial slopes of absorption over time plots were used to calculate reaction velocities according to the Beer-Lambert law.(TIF)Click here for additional data file.S3 FigWorms were treated with 5 μM  or 10 μM  harmonine or with an equivalent amount of solvent as negative control  for 72 h, with EdU added for the last 24 h. EdU-positive proliferating stem cells in female ovaries  or male testes . Stem cells are mainly found in the immature (iO) part of the ovary, not in the mature (mO) part. One z-plane of one representative female or male per condition from two experiments is shown. Scale bar: 35 μm.(TIF)Click here for additional data file.S1 MovieStill images are shown in (MPG)Click here for additional data file.


Scientific Reports 10.1038/s41598-018-35051-w, published online 12 November 2018Correction to: This Article contains typographical errors in the Results section where,20), Marinimicrobium, Marinobacter and Acinetobacter (Table 1). A decrease in biodiversity is observed as the salinity of the lagoons increase (Table 1), revealing the higher salinity tolerance of Marinimicrobium and Marinobacter species compared to that of Halomonas and Acinetobacter species here reported.”“Massive parallel sequencing of 16S ribosomal RNA gene amplicons showed that more than 60% of the sequences found in the lagoons belonged to only four main OTUs , specifically to the Class Gammaproteobacteria: Halomonas (found worldwideshould read:20), Marinimicrobium, Marinobacter and Acinetobacter (Table 2). A decrease in biodiversity is observed as the salinity of the lagoons increase (Table 2), revealing the higher salinity tolerance of Marinimicrobium and Marinobacter species compared to that of Halomonas and Acinetobacter species here reported.”“Massive parallel sequencing of 16S ribosomal RNA gene amplicons showed that more than 60% of the sequences found in the lagoons belonged to only four main OTUs , specifically to the Class Gammaproteobacteria: Halomonas (found worldwide


The use of vascular grafts is continuing to rise due to the increasing prevalence of coronary artery bypass grafting and microvascular flap-based tissue reconstructions. The current options of using native vessels (saphenous vein) or the synthetic grafts (Dacron) have been unable to manage current needs. In this study, we employed an original tissue engineering approach to develop a multi-layered vascular graft that has the potential to address some of the limitations of the existing grafts.Biomaterials, gelatin and fibrin, were used to develop a two-layered vascular graft. The graft was seeded with endothelial cells and imaged using confocal microscopy. The graft’s architecture and its mechanical properties were also characterized using histology, Scanning Electron Microscopy and rheological studies.Our methodology resulted in the development of a vascular graft with precise spatial localization of the two layers. The endothelial cells fully covered the lumen of the developed vascular graft, thus providing a non-thrombogenic surface. The elastic modulus of the biomaterials employed in this graft was found to be 5.186 KPa, paralleling that of internal mammary artery. The burst pressure of this graft was also measured and was found close to that of the saphenous vein (~2000 mm Hg).We were successfully able to employ a unique method to synthesize a multi-layered vascularized graft having adequate biological and mechanical properties. Studies are ongoing involving implantation of this developed vascular graft in the rat femoral artery and characterization of parameters such as vascular remodeling and patency. Using a combination of cells and biomaterials, this approach has resulted in the generation of tissues resembling muscle, bone, and skin. However, the development of vascular grafts has been an ongoing challenge. Vascular grafts are in constant need in surgery whether it is to extend the length of a pedicle of a free flap, span a zone of injury in replantation surgery, or bypass disease segment of artery in cardiovascular or peripheral vascular surgery.8 Tissue-engineered vascular grafts (TEVG) represent a potential solution to this problem.11 Multiple strategies have been developed in the creation of TEVGs since their inception in 1986, which include (1) scaffold methods, in which a synthetic material (such as Dacron) is seeded with recipient cells to simulate the tunica intima, (2) decellularized matrices, in which a tissue  is harvested from an animal, chemically decellularized to reduce antigenicity, and then seeded with recipient cells, and (3) self-assembled grafts, in which cell-laden biomaterials are shaped into vessels via methods such as direct molding, folding cellular sheets, and 3D printing.10Synthetic polymers such as Dacron and polytetrafluoroethylene (PTFE) are popular in large-diameter (>6 mm) applications but inadequate for small-diameter (<6 mm) applications with a high rate of thrombosis.12 On the other hand, small-diameter (<6 mm) TEVGs have not. A clinical trial conducted in the United States and Poland implanted small-diameter TEVGs as vascular access for hemodialysis in 60 patients with failing arteriovenous fistulas. Only 15% retained primary patency at 2 years.14Despite differences in methods of TEVG formation, no one approach has shown to be most effective. Each strategy has encountered individual difficulties which have prevented their widespread implementation, including lackluster mechanical properties, vessel size limitations, and thrombogenicity. Success of TEVGs has been largely dependent on graft size; medium-sized (12–24 mm diameter) TEVGs have shown early promising results.15 In this study, we hypothesized and showed that a multilayered approach in conjunction with a dual–half-lumen methodology could be used to construct a small-diameter TEVG. This new methodology allows for the seeding of endothelial cells with standard pipetting technique under direct visualization and allows confirmation of endothelial monolayer, an essential factor in maintaining patency, before graft assembly, without a sacrifice in mechanical strength. We used various assessment methods such as histology, scanning electron microscopy (SEM), elastic modulus, and burst pressure to report on our technique and results.Synthesizing small diameter TEVG with satisfactory mechanical properties and long-term patency rates has proved difficult, hindering the integration of TEVGs into clinical applications in reconstructive microsurgery, replantation, coronary artery bypass and grafting, and peripheral vascular surgery.°C in 5% CO2 in EGM-2 BulletKit CC-3162 . The cells were expanded in T-75 flasks between 5 and 7 passages; the culture media were changed every other day. Before seeding onto vascular grafts, cells were harvested using 0.25% trypsin, and 150,000 cells were added per graft and incubated in static culture for 4 days. In preliminary experiments, several different densities of cells were tested. The current density was found to be optimum in terms of favorable viability of cells and incubation period.Human umbilical vein endothelial cells were cultured at 37°C in an oven for 10 minutes. Following that, 75 µL of fibrinogen  was uniformly deposited onto this half-lumen, followed by addition of 75 µL of thrombin. The plate was then allowed to incubate for 5 minutes. The cells were then seeded directly on the top of this half-lumen of the graft using a 1-mL pipette. The cells were incubated for a period of 2 hours. Similarly, another half-lumen was generated. The 2 half-lumens were then joined together through the addition of fibrin sealant (thus creating a 2-cm-long and 6-mm-diameter vascular graft). This was followed by further incubation for a period of 4 days  was utilized to form the outer layer of the vascular graft. It was dissolved in distilled water 10% wt/vol), followed by filter sterilization using a 0.22-micron filter. It was then cross-linked through the addition of microbial transglutaminase (MTG) enzyme (10% wt/vol). Human Fibrin generated from EVICEL Fibrin Sealant  was used to form the inner layer (lumen) of the graft. Fibrinogen and thrombin were dissolved in equal volumes to produce fibrin. To develop a vascular graft, 3 mL of gelatin/MTG mixture was incubated overnight in a 12-well plate with a 6-mm diameter tube inserted at a depth that results in the development of half lumen of 3 mm in radius. The tube was then removed and any remaining MTG in the solidified gelatin was denatured by keeping the plate at 600% wt/vol4, followed by dehydration processes with ethanol. The slides were then sputter coated with Au/Pd particles and were imaged using Crossbeam 340, Carl Zeiss Microscope.The samples were fixed in 10% formalin, followed by paraffin embedding and sectioned into 5-µm-thick slices. These slices were stained with hematoxylin and eosin and Masson’s trichrome. Furthermore, gelatin fibrin ultrastructure was characterized using SEM. Briefly, 5-µm sections upon being mounted on glass slides were stained with 1% Os(OH)The endothelial cells lining the lumen were labeled with Hoechst 33342 dye and Alexa Fluor 488 phalloidin stain for 1 hour. Following washing with saline solution, the cells were imaged using Upright Confocal Microscope, Leica TCS SP8 X.Several rheology studies were conducted to determine the elastic modulus and shear stress of both the biomaterials involved—gelatin (after being cross-linked) and fibrin. The burst pressure was measured using an angioplasty balloon inflation device Fig. . Both enThe images of all histological stains at different magnifications  were recorded using a Nikon Eclipse E800 microscope.Distinct gelatin–fibrin interfaces were observed in both imaging modalities Fig. .Following 4 days of incubation of cells onto the fibrin-composed lumen, a confluent endothelium was obtained as demonstrated in Figure The gelatin–fibrin combination used in the final design (10% gelatin base with overlaid fibrin coating) had an elastic modulus of 3433 pascals (Pa) Fig. . IncreasConstructed grafts were noted to burst at internal pressures of approximately 2000 mm Hg (n = 3). Bursting in all trials originated within the plane of the fibrin sealant between the 2 half-lumens; no leak was visualized through the gelatin of either half lumen at the time of graft bursting.TEVGs have found success in medium-to-large-diameter applications; however, their results in small-diameter applications have been discouraging. This has spurred motivation to engineer a graft that exceeds the patency and mechanical properties of native vascular conduits, allows for unlimited supply of vascular grafts, and obviates the morbidity associated with their harvesting. In this study, we describe the biological and mechanical properties of a small-diameter TEVG constructed using unique a dual–half-lumen methodology.The endothelial cells used in this study successfully grew along the curved surface of this 2-cm-long and 6-mm-diameter graft, and there was no neointimal hyperplasia observed . These cells  were chosen for their easy availability and quick proliferation in in vitro studies. However, our methodology could be employed for the lining of both venous and arterial cells onto vascular grafts and for any length or diameter of graft. In future clinical applications, we foresee the use of the patient’s native progenitor cells from the blood or marrow used for seeding these custom-designed grafts.16 In this study, a confluent antithrombogenic endothelial monolayer was achieved as demonstrated via confocal microscopy following 4 days of incubation ; 6.9 ± 1.7 kPa/unit strain when subjected to 100 cm Hg.21 However, by altering our biomaterial concentrations, we achieved a modulus of 5.186 kPa, paralleling the elasticity of the IMA. These data are encouraging as it suggests that our construct may achieve physiologic elasticity simply by altering the concentrations of graft components.Several mechanical properties key to successful in vivo implementation were investigated after the construction of our TEVG. Historically, elasticity has been an important marker of graft stability. A significant difference in elasticity between an implanted native vessel and an implanted conduit results in turbulence at the sites of anastomosis. This ultimately precipitates graft failure secondary to complications such as graft ectasia, aneurysm, and thrombus formation.25 These considerable ranges in native vessel mechanical properties have been attributed to the effects of age-related changes, atherosclerosis, and inherent differences in vessel diameter.27 Previous models of TEVGs have had no problem achieving adequate burst pressure. Most constructs have shown the ability to withstand pressures >1500 mmHg28 with others demonstrating burst pressures upward of 3500.24 Thus, it is to be expected that a new TEVG such as the one created in this experiment would have burst pressures in the 1500–3500 mm Hg range. Our graft’s burst pressure of approximately 2000 mm Hg is most represented by the strength of the fibrin sealant joining the 2 half-lumens rather than of the actual graft wall. Because bursting occurred between the half-lumens first before occurring through the gelatin wall, we postulate that different types of half-lumen sealant would result in different burst pressures for grafts made using this dual–half-lumen method. It is worth noting that for any given method of TEVG, graft burst pressure is variable and is known to change with differing graft length.22 Additionally, according to Laplace’s law, differences in graft radius will also influence wall tension, and thus, burst pressure. These principles are important when attempting to extrapolate a graft’s performance at differing diameters and lengths and suggest that there likely exists the need for several different methodologies to construct successful grafts of varying diameter.Adequate burst pressure is another measure of graft stability that is critical in the development of TEVGs. Inadequate wall strength proposes a dangerous scenario where a graft is unable to withstand arterial pressures and leaks or becomes aneurysmal and ruptures after being implanted. Native vascular grafts demonstrate burst pressures ranging from 1600 to 2400 mm Hg for great saphenous vein (GSV) grafts and 3200–4225 mm Hg for IMA grafts.30 The striking differences between the viability of the GSV and IMA grafts are typically attributed to increased rates of acute thrombosis, intimal hyperplasia, and accelerated rates of atherosclerosis in vein grafts.29 Although strategies such as antiplatelet therapy and cholesterol control have led to improved patency rates, there exists the opportunity for TEVGs to improve on long-term graft patency. Polyglycolic acid scaffold-based TEVGs have demonstrated 4-week patency rates approaching 100% in porcine models,31 and polycaprolactone/chitosan-based grafts have shown promising results in sheep.32 However, TEVGs have had variable results when implemented in humans, and there is currently no small-diameter TEVG that has shown promising results in human subjects.14 Commercial products such as Lifeline Vascular Graft, GORE Propaten, and Humacyte Acellular Vessel suffer from several limitations including poor long-term patency, extensive construction times, and the use of xenograft or allogenic cells. Considering, there are around 1.4 million people per year in the United States alone in the need of vascular grafts, the need to explore new ways of synthesizing biocompatible grafts with long-term patencies and short production time is paramount.Autologous vessels have historically been notorious for their suboptimal long-term patency rates. The often-used GSV has a patency rate of only 57%–61% after 10 years, compared with the IMA which has 10-year patency rates that approach 90%.In this preliminary proof of concept study, we have shown that our new multilayered approach, in conjunction with a dual–half-lumen methodology, can be used to construct a small-diameter TEVG. The development and confirmation of a functional, adherent endothelium before implantation is essential to inhibit thrombosis. The graft’s mechanical properties match favorably to GSV and IMA conduits. It is comparable with regard to elasticity and bursting strength and can function without macroscopic evidence of burst, leak, or structural damage. We are currently in the process of modifying the graft Fig.  to reducThe authors thank Yan Ji (Research Histology Core Laboratory) and Ya-Chen Chuang (ThINC facility at AERTC) at Stony Brook University with help at histological samples preparation, confocal and SEM images acquisition. The authors are equally grateful to Alice Shih with help in cell culture.