First-order Branches Research Articles

A novel coating method to reduce membrane infolding through pre-crimping of covered stents – Computational and experimental evaluation

A covered stent has been used to treat carotid artery stenosis to reduce the chance of embolization, as it offers improved performance over bare-metal stents. However, membrane infolding of covered stents can affect efficiency and functionality for treating occlusive disease of first-order aortic branches. In order to mitigate the degree of infolding of the stent once it was re-expanded, we proposed a new coating method performed on the pre-crimped stent. A systematic study was carried out to evaluate this new coating technique: a) in vivo animal testing to determine the degree of membrane infolding; b) structural finite element modeling and simulation were used to evaluate the mechanical performance of the covered stent; and c) computational fluid dynamics (CFD) to evaluate hemodynamic behavior of the stents and risk of thrombosis after stent deployment. The degree of infolding was substantially reduced as demonstrated by the in vivo deployment of the pre-crimped stent compared to a conventional dip-coated stent. The structural analysis results demonstrated that the membrane of the covered stent manufactured by conventional dip-coating resulted in a large degree of infolding but this could be minimized by our new pre-crimped coating method. CFD studies showed that the new coating method reduced the risk of thrombosis compared to the conventional coating method. In conclusion, both simulation and in vivo testing demonstrate that our new pre-crimped coating method reduces membrane infolding compared with the conventional dip-coating method and may reduce risk of thrombosis.

Single-neuron projectome of mouse prefrontal cortex.

Prefrontal cortex (PFC) is the cognitive center that integrates and regulates global brain activity. However, the whole-brain organization of PFC axon projections remains poorly understood. Using single-neuron reconstruction of 6,357 mouse PFC projection neurons, we identified 64 projectome-defined subtypes. Each of four previously known major cortico-cortical subnetworks was targeted by a distinct group of PFC subtypes defined by their first-order axon collaterals. Further analysis unraveled topographic rules of soma distribution within PFC, first-order collateral branch point-dependent target selection and terminal arbor distribution-dependent target subdivision. Furthermore, we obtained a high-precision hierarchical map within PFC and three distinct functionally related PFC modules, each enriched with internal recurrent connectivity. Finally, we showed that each transcriptome subtype corresponds to multiple projectome subtypes found in different PFC subregions. Thus, whole-brain single-neuron projectome analysis reveals organization principles of axon projections within and outside PFC and provides the essential basis for elucidating neuronal connectivity underlying diverse PFC functions.

Major Aortopulmonary Collateral Arteries.

Major aortopulmonary collateral arteries (MAPCAs) are congenital vessels that arise from the aorta or its first-order branches and are distally connected to the pulmonary arterial vasculature, thereby providing pulmonary blood flow. MAPCAs are commonly associated with several congenital heart diseases that have compromised pulmonary circulation due to severe stenosis involving pulmonary valves or arteries or due to pulmonary atresia. Embryologically, MAPCAs are presumed to be persistent segmental arteries. MAPCAs can be imaged with CT and MRI, and such imaging findings are important for surgeons and interventionists. The management options for MAPCAs include unifocalization, surgical ligation, and endovascular interventions, such as coil embolization. This review highlights the role of reporting certain critical features of MAPCAs at CT and MRI, which will help to facilitate management decisions for systemic-to-pulmonary collateral vessels observed in patients with congenital heart disease. Keywords: Pediatrics, CT Angiography, Image Postprocessing, Interventional-Vascular, MR Angiography, Embolization, Stents, Cardiac, Vascular, Aorta © RSNA, 2022.

Estimation of Larch Growth at the Stem, Crown, and Branch Levels Using Ground-Based LiDAR Point Cloud

Tree growth is an important indicator of forest health and can reflect changes in forest structure. Traditional tree growth estimates use easy-to-measure parameters, including tree height, diameter at breast height, and crown diameter, obtained via forest in situ measurements, which are labor intensive and time consuming. Some new technologies measure the diameter of trees at different positions to monitor the growth trend of trees, but it is difficult to take into account the growth changes at different tree levels. The combination of terrestrial laser scanning and quantitative structure modeling can accurately estimate tree structural parameters nondestructively and has the potential to estimate tree growth from different tree levels. In this context, this paper estimates tree growth from stem-, crown-, and branch-level attributes observed by terrestrial laser scanning. Specifically, tree height, diameter at breast height, stem volume, crown diameter, crown volume, and first-order branch volume were used to estimate the growth of 55-year-old larch trees in Saihanba of China, at the stem, crown, and branch levels. The experimental results showed that tree growth is mainly reflected in the growth of the crown, i.e., the growth of branches. Compared to one-dimensional parameter growth (tree height, diameter at breast height, or crown diameter), three-dimensional parameter growth (crown, stem, and first-order branch volumes) was more obvious, in which the absolute growth of the first-order branch volume is close to the stem volume. Thus, it is necessary to estimate tree growth at different levels for accurate forest inventory.

A new Late Devonian flora from Sonid Zuoqi, Inner Mongolia, northeastern China

AbstractThe Silurian and Devonian plant fossil record is the basis for our understanding of the early evolution of land plants, yet our appreciation of early global phytogeographic evolution has been constrained by the focus of most studies on deposits from Europe, North America, and, more recently, South China. Devonian plants have been recorded rarely from northeastern China, and among previous records, few plants have been illustrated and formally described. In this article, megafossil plants representing a Late Devonian-aged (probably Famennian) flora are described from a locality at northern Sonid Zuoqi, Inner Mongolia, NE China. The flora includes Melvillipteris sonidia new species, Archaeopteris sp., and fragments of some other plants. The new plant shows main axes and two orders of lateral branches. The first-order branches of this plant show a typical zigzag appearance and are borne in pairs on main axes. Second-order branches are straight or slightly flexed, and are borne helically or alternately on first-order branches. Sterile ultimate appendages and fertile structures of M. sonidia n. sp. are borne alternately on second-order branches. An associated palynological assemblage, as well as U-Pb ages of detrital zircon grains from adjacent horizons, are also reported, indicating a Late Devonian age in accord with the megafossil plants. The present study contributes to our appreciation of the Devonian floristic diversity of the Xing'an Block, and, through our review of the record of early vascular plants from NE China, more broadly to the understanding of the mid-latitude vegetation of the Northern Hemisphere during the Late Devonian.

Рост клонов плюсовых деревьев сосны обыкновенной, отобранных в Нижегородской области по смолопродуктивности

The taxational indicators of clones of plus trees of Scots pine, selected by resin productivity, were studied in comparison with similar characteristics of plants, selected by linear parameters of the trunk. They are represented They are presented in the assortment of the forest seed plantation No. 10 in the Semenovsky forestry of the Nizhny Novgorod region, created in 1984 on a plot with the type of forest growing conditions — B2, and the type of forest — maynikovo-lingonberry pine. In the organization of the work, the principle of the only logical difference was observed, as well as the requirements for the typicality, suitability and expediency of the experience. As a test marker for checking the purity of the clonal composition of the plantation, the value of the angle of attachment of the first-order lateral branches to the trunk was used. The height and diameter of the trunk are taken into account in 571 trees with a continuous list. The distribution of the average values of the analyzed indicators in the vegetative offspring of plus trees compared with each other is not uniform. The highest height (16,70 ± 0,43 m) observed in clones of the K-011 plus tree selected by resin productivity is 2,65 m or 1,19 times higher than the lowest value (14,05 ± 0,44 m) inherent in clones of the K-113 plus tree selected by the same criteria, and 2,02 m or 1,14 times higher than the lowest value (14,23 ± 0,31 m) inherent in clones of the K-171 plus tree selected by the same criteria taxational indicators of the trunk. Differences in the taxational indicators of clones in the group of plus trees distinguished by resin productivity, as well as in the group of trunks distinguished by characteristics, correspond to the level of significant ones, which indicates the specificity of their genotypes. The degree of similarity of the plus trees in terms of trunk parameters is not the same, which indicates a different level of individual non-identity of each of the plus trees in relation to the others in their considered population.

Challenging the Treatment Paradigm: Selecting Patients for Surgical Management of Hepatocellular Carcinoma with Portal Vein Tumor Thrombus.

Portal vein tumor thrombus (PVTT) remains a common presentation in patients with hepatocellular carcinoma (HCC). Approximately 30–50% of patients newly diagnosed with HCC will present with a concomitant PVTT. Current guidelines recommend systemic therapy for treatment of HCC with PVTT. Real-world application of partial hepatectomy in HCC patients with PVTT has increased over the past two decades, as perioperative complications have declined. However, it is unclear if there is an association between the extent of PVTT and overall survival and rates of recurrence and whether the perioperative morbidity outweighs these potential benefits. Partial hepatectomy with en bloc resection of PVTT in second-order branches and distal can offer significant benefits in carefully selected patients; however, once the HCC-associated PVTT extends into first-order portal venous branches or more proximal into the superior mesenteric vein, the risks of surgical resection outweigh the benefits. The aim of this review is to determine which patients with HCC presenting with PVTT benefit from surgical resection. We will discuss the classification systems of PVTT and review both outcome and perioperative measures in patients undergoing partial hepatectomy with extirpation of HCC-related PVT.

Hepatocellular carcinoma with portal vein invasion: Non-surgical treatment

A substantial proportion of patients with hepatocellular carcinoma (HCC) present with portal vein invasion (PVI). The extent of portal vein tumor thrombosis (PVTT) can be classified into 4 categories: Vp1, existence of PVTT distal to the second-order branches of portal vein; Vp2, existence of PVTT in the second-order branches of portal vein; VP3, PVTT in the first-order branches of portal vein; and VP4, existence of PVTT in main portal trunk or portal branches contralateral to primary involved lobe. The degree of PVTT has shown the close association with prognosis of HCC across all treatment options. Clinical practice guidelines recommend systemic therapy for advanced HCC with PVI based on the highest level of evidence. Sorafenib has firstly shown to improve overall survival of patients with advanced HCC in 2007 [1]. Among 299 sorafenib-treated patients, 108 (36%) had macrovascular invasion. Subgroup analysis consistently demonstrated significantly longer overall survival (8.1 vs. 4.9 months; hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.49-0.93) and time to progression (4.1 vs. 2.7 months; HR, 0.57; 95% CI 0.39-0.84) in sorafenib-treated patients with macrovascular invasion [2]. Lenvatinib, another 1st-line systemic agent, has proven non-inferiority to sorafenib in advanced HCC [3]. The REFLECT study included patients with macroscopic portal vein invasion (199/954, 21%); however, it excluded patients with main portal vein invasion. Recently approved systemic agents, atezolizumab plus bevacizumab was superior to sorafenib in overall survival and progression-free survival [4]. Of 336 atezolizumab-bevacizumab treated patients, 38% had macrovascular invasion. Atezolizumab with bevacizumab also showed significant efficacy in patients with microvascular invasion (HR 0.58 [95% CI, 0.38-0.89] for overall survival; HR 0.53 [95% CI, 0.37-0.76] for progression-free survival). Transarterial therapy and/or radiotherapy can also be an option for HCC with PVI. A single-center randomized controlled study has demonstrated that transarterial chemoembolization with external beam radiotherapy significantly improved progression-free survival and overall survival compared with sorafenib in patients with macroscopic vascular invasion [5]. Earlier studies reported that transarterial chemoembolization improved overall survival of HCC patients with PVTT compared to supportive care [6,7] Recent meta-analysis indicated that radioembolization was safer and more effective than sorafenib in HCC with PVI [8].

Endothelial RIPK3 Regulation and its Effects on Vascular Permeability Following Intestinal Ischemia‐Reperfusion Injury

The cytoplasmic protein receptor-interacting serine/threonine-protein kinase 3 (RIPK3) is primarily known for promoting necroptosis, but more recent findings suggest that RIPK3 has additional functions separate from necroptosis. Our lab recently demonstrated that in the absence of the chromatin-remodeling enzyme CHD4, RIPK3 is elevated in hypoxic cultured embryonic endothelial cells (ECs) and that elevated RIPK3 causes vessel fragility in midgestation mouse embryos. Our current study investigates the regulation of endothelial RIPK3 following intestinal ischemia-reperfusion injury (IRI) in mice and its effects on vascular permeability and damage following IRI. To assess RIPK3 regulation following IRI, first-order branches of the superior mesenteric artery were clamped for 1 hr to induce ischemia, and clamps were removed subsequently for 24 hr reperfusion (C57BL/6J mice; 10-12 weeks old). Unclamped vessels and downstream gut tissue from the same animal were used as sham controls. RIPK3 and VE-Cadherin expression (mean fluorescence intensity; MFI) were quantified in 1st and 2nd order mesenteric arteries using immunostaining of en face vessel preparations. RIPK3 was significantly elevated (P=0.0216) at 1 hr ischemia and following 24 hr IR injury (P=0.0295) compared to sham controls (7-8 vessels/group, n=4 mice). Junctional VE-Cadherin showed increased expression (not significant) following 1 hr ischemia. Although no changes were observed following 24 hr IRI, VE-Cadherin expression at mesenteric arterial endothelial junctions were discontinuous and unstable suggesting a potential barrier dysfunction associated with IRI. To assess the role of RIPK3 on vascular permeability, we used Ripk3fl/fl;Cdh5(PAC)-CreERT2 mice (Ripk3 endothelial cell knockout=RIPK3ECKO) compared to littermate controls, and vascular permeability was assessed using the Evans blue assay following 24 hr intestinal IRI. Gut vascular permeability was increased following IRI in both RIPK3ECKO (n=4 mice)and littermate controls (n=3 mice), however permeability was also significantly increased (P=0.02) in sham gut regions and the livers (P=0.04) of RIPK3ECKO mice unlike in controls. Collectively, these data suggest that deletion of endothelial RIPK3 increases vascular damage downstream of injury sites and points toward a protective role for RIPK3 in the vasculature following IRI. Future studies evaluating mechanisms of RIPK3 protective effects in endothelial cells following IRI will provide insight into therapeutic targets for vessel recovery from IRI.

The Impact of Short-term Thermal Stress on the Consequent Germination of Dill Seeds

The authors obtained new data on the germination of dill seeds, which were gathered from the first-order and second-order branches, after short-term thermal stress (40 °C). The seeds were germinated in a thermostat. The swollen seeds (4 replications with 100 seeds each) were incubated at 40 °C for 1 to 5 days. The seeds in the control group were not incubated. After the incubation, the seeds were transferred to the standard (t = 20 °C) conditions and germinated on filter paper in Petri dishes without light for 21 days. In this study, the authors employed the dynamic method of seed germination analysis. To plot the seed germination curve, the authors used a log-logistic regression with three parameters: b, d, and e. The statistical analysis was conducted in R 3.4.3. The authors determined the duration of heat stress that inhibits the germination speed and germination rate of seeds. Seeds gathered from the first-order branches (“first-order seeds” from now onward) after 1-day to 3-day incubation germinated similarly to the control group. Increasing the incubation period to 4–5 days sharply reduced the germination speed. Seeds gathered from the second-order branches (“second-order seeds” from now onward) were less resistant to high-temperature stress. Three-day incubation completely precluded germination. The germination time of 50% (T50) of the first-order seeds slowed by 0.92±0.11–6.4±0.49 days because of the gradual increase in incubation time. The second-order seeds that incubated for 1–2 days germinated significantly slower than the control group seeds. After this point, further incubation precluded germination. Upon reaching the incubation threshold, the germination rate curves steepened and then continued falling up to the full germination stop. The maximum incubation time (at 40 °C), after which germination was possible in standard temperature conditions, was 3.69±0.06 days for the first-order seeds, and 2.00±0.19 days for the second-order roots. The differences in data were statistically significant at p-value < 0.001

Liver Resection Combined with Backflow Trombectomy and Sdjuvant TACE for Hepatocellular Carcinoma Infiltrating the Portal Vein and its Main Branches

Introduction: Hepatocellular carcinoma (HCC) tends to invade the intrahepatic vasculature, especially the portal vein (PV). Portal vein tumor thrombosis (PVTT) represents a strong negative prognostic factor, due to the increased risk of tumor spread into the bloodstream, with a median survival of 3 months without treatment. Sorafenib represents at the present time the recommended therapy in this category of patients, giving a small prolongation of life expectancy. However, some surgical series reported better outcomes in patients with gross PVTT (PVTT in the portal trunk, its first-order branch, or its second-order branch), and preserved liver function, the 3-year and 5-year survival rates are 15% to 28% and 0% to 17%, respectively. Efficacy of adjuvant strategies is still under debate. Methods: We observed a 74-year-old man with HBV-related chronic hepatitis and incidental diagnosis of a large liver mass at ultrasound examination. Triphasic spiral computed tomographic scan confirmed HCC 8 cm in diameter in the left lobe of the liver. In addition, PVTT of the main portal trunk and left branch that extended to the right PV was present (Vp4, Liver Cancer Study Group of Japan). Results: The procedure included left hepatectomy and PV thrombectomy during clamping of the distal PV trunk. The PV was incised at the bifurcation, and the thrombus was extracted with the help of the backflow from the distal branches. PV clamping and length of operation were 8 and 220 minutes respectively. Intraoperative blood loss was 1200 mL. The patient was discharged on postoperative day 6th. An adjuvant Transarterial chemoembolization (TACE) was performed 20 days after surgery. The patient was disease-free in the liver at 60 days after surgery, but lung metastasis appeared thereafter. The patient is curretly alive 6 months after surgery. Conclusions: HCC with PVTT is a complex anatomical and clinical condition, including a wide range of patients with different prognosis and new treatment possibilities according to the degree of PV involvement, tumor biological aggressiveness, complications caused by portal hypertension, patient’s clinical features and tolerance to antineoplastic treatments. Patients with HCC and PVTT still remain a subgroup with poor survival, but they can benefit from an aggressive multimodal approach in selected cases. Liver resection associated with adjuvant TACE should be considered a possible therapeutic option to prolong survival of HCC patients with PVTT.

Safety and Efficacy of Camrelizumab Combined with Apatinib for Advanced Hepatocellular Carcinoma with Portal Vein Tumor Thrombus: A Multicenter Retrospective Study.

IntroductionPrevious trials demonstrated that anti-angiogenesis or anti-programmed death protein 1 (PD-1) monotherapy showed unsatisfied effect in advanced hepatocellular carcinoma (HCC). No study existed that focus on the effects of camrelizumab and apatinib (“C+A”) combination therapy for HCC patients with the location and extent of portal vein tumor thrombus (PVTT) as the main variable being assessed. This study was to compare the efficacy and tolerability of “C+A” for HCC patients with PVTT.MethodsWe retrospectively analyzed patients with advanced HCC and PVTT who underwent “C+A” therapy in a multicenter retrospective cohort from Jan 2019 to July 2020. Outcomes of patients who underwent “C+A” were analyzed by using the Kaplan–Meier method according to types of PVTT: PVTT in the main portal vein (type A), PVTT in the first-order portal vein branch (type B), and PVTT in second- or lower-order portal vein branches (type C).ResultsSixty-three patients were finally included and the mean duration of follow-up was 12.6 ± 4.5 months. The objective response rate (ORR) and disease control rate (DCR) for the whole cohort were 44.0% and 75.0%, respectively. The median overall survival (OS), progression-free survival (PFS) and time to progression (TTP) were 14.8 months, 11.8 months and not yet reached (NR), respectively. Patients with type B (OS, 15.9 months; PFS, 14.0 months; TTP, NR) or type C (OS, 16.0 months; PFS, 14.9 months; NR) PVTT appear to have better survival benefits compared with type A (OS, 5.8 months; PFS, 5.0 months; TTP, 7.0 months). Along with AFP, the absence of main PVTT was an independent predictive factor for survival at uni- and multivariate analysis.ConclusionCamrelizumab and apatinib yielded a promising outcome in patients with advanced HCC who developed a tumor thrombus in the first lower-order portal vein branches and was generally safe and had manageable side effects.

Apple Tree Branch Information Extraction from Terrestrial Laser Scanning and Backpack-LiDAR

The branches of fruit trees provide support for the growth of leaves, buds, flowers, fruits, and other organs. The number and length of branches guarantee the normal growth, flowering, and fruiting of fruit trees and are thus important indicators of tree growth and yield. However, due to their low height and the high number of branches, the precise management of fruit trees lacks a theoretical basis and data support. In this paper, we introduce a method for extracting topological and structural information on fruit tree branches based on LiDAR (Light Detection and Ranging) point clouds and proved its feasibility for the study of fruit tree branches. The results show that based on Terrestrial Laser Scanning (TLS), the relative errors of branch length and number are 7.43% and 12% for first-order branches, and 16.75% and 9.67% for second-order branches. The accuracy of total branch information can reach 15.34% and 2.89%. We also evaluated the potential of backpack-LiDAR by comparing field measurements and quantitative structural models (QSMs) evaluations of 10 sample trees. This comparison shows that in addition to the first-order branch information, the information about other orders of branches is underestimated to varying degrees. The root means square error (RMSE) of the length and number of the first-order branches were 3.91 and 1.30 m, and the relative root means square error (NRMSE) was 14.62% and 11.96%, respectively. Our work represents the first automated classification of fruit tree branches, which can be used in support of precise fruit tree pruning, quantitative forecast of yield, evaluation of fruit tree growth, and the modern management of orchards.

Modeling the number of the first- and second-order branches within the live tree crown of Korean larch plantations in Northeast China

Modeling the number of branches in a tree is fundamental for simulating other branch characteristics and crown structure. In this study, a total of 77 Korean larch (Larix olgensis Henry) trees were destructively sampled from plantations in Northeast China. The number of first- and second-order branches was modeled using seven count data models, namely Poisson, negative binomial (i.e., NB, including NB-1, NB-2, and NB-P), and generalized Poisson (i.e., GP, including GP-1, GP-2, and GP-P) regression models. Generalized linear mixed models (GLMMs) were then applied to those models using the sampled trees as the random effects. The results showed that (i) the Poisson regression was preferred for modeling the number of first-order branches; (ii) the GP-1 regression was considered the optimal model for the number of second-order branches; (iii) the significant predictor variables included tree height increment, branch position, relative tree size, mean dominant height, and tree age; (iv) the GLMMs significantly improved both model fit and prediction performance; (v) the prediction accuracy of the GLMMs increased gradually with increasing sample size; and (vi) a relatively small sample size with an appropriate sampling strategy would be adequate to provide a good estimation at a specific crown section.

Retrieval of Aerodynamic Parameters in Rubber Tree Forests Based on the Computer Simulation Technique and Terrestrial Laser Scanning Data

Rubber trees along the southeast coast of China always suffer severe damage from hurricanes. Quantitative assessments of the capacity for wind resistance of various rubber tree clones are currently lacking. We focus on a vulnerability assessment of rubber trees of different clones under wind disturbance impacts by employing multidisciplinary approaches incorporating scanned points, aerodynamics, machine learning and computer graphics. Point cloud data from two typical rubber trees belonging to different clones (PR107 and CATAS 7-20-59) were collected using terrestrial laser scanning, and a connection chain of tree skeletons was constructed using a clustering algorithm of machine learning. The concept of foliage clumps based on the trunk and first-order branches was first proposed to optimize rubber tree plot 3D modelling for simulating the wind field and assessing the wind-related parameters. The results from the obtained phenotypic traits show that the variable leaf area index and included angle between the branches and trunk result in variations in the topological structure and gap fraction of tree crowns, respectively, which are the major influencing factors relevant to the rubber tree’s capacity to resist hurricane strikes. The aerodynamics analysis showed that the maximum dynamic pressure, wind velocity and turbulent intensity of the wind-related parameters in rubber tree plots of clone PR107 (300 Pa, 30 m/s and 15%) are larger than that in rubber tree plots of clone CATAS-7-20-59 (120 Pa, 18 m/s and 5%), which results in a higher probability of local strong cyclone occurrence and a higher vulnerability to hurricane damage.

Study of the phylogeny and distribution of Pterocladiella (Pterocladiaceae, Rhodophyta) from China

ABSTRACTIn the current study, 334 specimens of Pterocladiella from China representing historical herbarium specimens and recent field collections were re-examined based upon morphological and molecular data analyses. Both datasets revealed the presence of P. beachiae, P. capillacea, P. caerulescens, and P. musciformis. Of these species, P. beachiae and P. musciformis were new records for China. Pterocladiella beachiae was characterised by a complanate thallus, with first-order short branches opposite or alternate in the upper part of the plant and marginal proliferations in the upper axis and branches; Pterocladiella musciformis had distinctive acute branch apices, cylindrical or slightly compressed lower axes, compressed upper axes, and simple irregular branches occurring either laterally or clustered. P. caerulescens had a corymbose outline and was monoecious. In the field, P. capillacea was the most common species of Pterocladiella, being widely distributed along Chinese coasts, whereas other Pterocladiella species were geographically limited in southern China. In P. capillacea, the tetrasporophyte was the dominant reproductive type while gametophytes were less common and more likely occurred in the East China Sea and South China Sea at lower latitudes.

Hepatic Resection With Thrombectomy in the Treatment of Hepatocellular Carcinoma Associated With Macrovascular Invasion

IntroductionMacrovascular invasion (MVI) in patients with hepatocellular carcinoma (HCC) is a very poor prognostic factor. Treatment in such cases is still a matter of debate. The goal of this study is to assess short- and long-term results of liver resection and thrombectomy in a series of patients with HCC and MVI. MethodsRetrospective cohort study of patients who underwent liver resection for HCC in the period 2007–2015 (n = 120). Of all the patients, 108 did not have MVI, while 12 presented with MVI: 1 patient in the common portal vein (Vp4), 8 patients in first-order portal branches (Vp3), 1 patient in a sectorial branch (Vp2), 1 patient in a segmental branch (Vp1); another patient presented with tumor thrombus in a main hepatic venous branch in the confluence with the vena cava (Vv2). ResultsPatients with MVI needed major hepatic resection more frequently than patients without MVI (83.3% vs 25.9%, P < .0001), with no differences in postoperative mortality or severe morbidity. Patients with MVI required a longer operative time and developed more frequently postoperative ascites (33.3% vs 9.3%, P = .034).Global survival at 1, 3 and 5 years was 66.7%, 33.3% and 22.2% in patients with IMV, and 90.7%, 72.4% and 52.2% in patients without IMV (P = .009), respectively. ConclusionsHepatectomy associated with thrombectomy might be justified in a selected group of patients with HCC and MVI, offering a potential benefit in survival with acceptable morbidity.

ДОСЛІДЖЕННЯ ВПЛИВУ ШВИДКОСТІ ОХОЛОДЖЕННЯ ПРИ ЗАТВЕРДІННІ БЕЗПЕРЕРВНОЛИТОЇ ЗАГОТОВКИ НА ОСОБЛИВОСТІ ДЕНДРИТНОЇ СТРУКТУРИ ВУГЛЕЦЕВОЇ СТАЛІ

The analysis of the formation process of the cast structure of carbon steel grade EA1N (EN 13261: 2009 + A1: 2010 (Е)) after the completion of its crystallization with a change in a wide range of metal cooling rate during solidification of a continuously cast billet (ССB) with a diameter of 470 mm has been carried out. The effect of the cooling rate during the solidification of ССB Ø 470 mm on the parameters of the chemical heterogeneity of the distribution of silicon and manganese in the microstructure of carbon steel has been shown. It has been determined that the effect of the metal cooling rate during the solidification of the investigated CCB on the size of dendritic crystals is described by the inversely proportional relationship: у = 510,85 х-0,156. With a change in the cooling rate of the metal during solidification from 106 до 1 ℃ / min, the size of the dendrites in the direction from the surface to the central layers of the CCB Ø 470 mm increased by ~ 8 times, and the density of the dendritic structure of carbon steel EA1N decreases by 64 times. In this case, the nature of its dependence on the intensity of heat removal is the opposite nature of the change in the size of dendrites. It has been established that by varying the cooling rate in the range 1 – 106 ℃ / min, one can achieve a significant change in the average size and density of dendritic crystals while maintaining the constancy of the volume fraction of segregation areas of silicon and manganese ~ 23% in carbon steel (~ 0.4 % wt. C). The results of X-ray spectral analysis of samples of ССB Ø 470 mm made of carbon steel grade EA1N showed that the maximum content of silicon and manganese is characteristic of the former spaces between the first-order dendritic branches, their minimum content is for the former dendritic branches. At the same time, the amount of these elements in steel microvolumes, which are the former spaces between the second-order dendritic branches, is on average 50 % more than in the former dendritic branches. It has been determined that in the entire investigated range of cooling rates 1 – 106 ℃ / min, the coefficients of dendritic segregation КдI and КдII of silicon and manganese change insignificantly and amount to 1.8-1.9 and 1.5 for КдI and КдII, respectively. In this case, the values of the coefficients КдI and КдII for both elements are practically constant in both pearlite and ferrite. It has been proven that both silicon and manganese have high diffusion mobility only at sufficiently high temperatures, when steel is in a solid-liquid state. Based on the results of X-ray microanalysis, it has been established that the heterogeneity of the distribution of chemical elements, which is formed as a result of dendritic segregation of silicon and manganese, is the primary and constant component of the microstructure of carbon steel.

MuSCA: a multi-scale source-sink carbon allocation model to explore carbon allocation in plants. An application to static apple tree structures.

Background and aimsCarbon allocation in plants is usually represented at a topological scale, specific to each model. This makes the results obtained with different models, and the impact of their scales of representation, difficult to compare. In this study, we developed a multi-scale carbon allocation model (MuSCA) that allows the use of different, user-defined, topological scales of a plant, and assessment of the impact of each spatial scale on simulated results and computation time.MethodsModel multi-scale consistency and behaviour were tested on three realistic apple tree structures. Carbon allocation was computed at five scales, spanning from the metamer (the finest scale, used as a reference) up to first-order branches, and for different values of a sap friction coefficient. Fruit dry mass increments were compared across spatial scales and with field data.Key ResultsThe model was able to represent effects of competition for carbon assimilates on fruit growth. Intermediate friction parameter values provided results that best fitted field data. Fruit growth simulated at the metamer scale differed of ~1 % in respect to results obtained at growth unit scale and up to 60 % in respect to first order branch and fruiting unit scales. Generally, the coarser the spatial scale the more predicted fruit growth diverged from the reference. Coherence in fruit growth across scales was also differentially impacted, depending on the tree structure considered. Decreasing the topological resolution reduced computation time by up to four orders of magnitude.ConclusionsMuSCA revealed that the topological scale has a major influence on the simulation of carbon allocation. This suggests that the scale should be a factor that is carefully evaluated when using a carbon allocation model, or when comparing results produced by different models. Finally, with MuSCA, trade-off between computation time and prediction accuracy can be evaluated by changing topological scales.

Resección hepática con trombectomía en el tratamiento del carcinoma hepatocelular con invasión vascular macroscópica

IntroductionMacrovascular invasion (MVI) in patients with hepatocellular carcinoma (HCC) is a very poor prognostic factor. Treatment in such cases is still a matter of debate. The goal of this study is to assess short- and long-term results of liver resection and thrombectomy in a series of patients with HCC and MVI. MethodsRetrospective cohort study of patients who underwent liver resection for HCC in the period 2007-2015 (n=120). Of all the patients, 108 did not have MVI, while 12 presented with MVI: 1patient in the common portal vein (Vp4), 8patients in first-order portal branches (Vp3), 1patient in a sectorial branch (Vp2), 1patient in a segmental branch (Vp1); another patient presented with tumor thrombus in a main hepatic venous branch in the confluence with the vena cava (Vv2). ResultsPatients with MVI needed major hepatic resection more frequently than patients without MVI (83.3% vs 25.9%, P<.0001), with no differences in postoperative mortality or severe morbidity. Patients with MVI required a longer operative time and developed more frequently postoperative ascites (33.3% vs 9.3%, P=.034).Global survival at 1, 3 and 5years was 66.7%, 33.3% and 22.2% in patients with IMV, and 90.7%, 72.4% and 52.2% in patients without IMV (P=.009), respectively. ConclusionsHepatectomy associated with thrombectomy might be justified in a selected group of patients with HCC and MVI, offering a potential benefit in survival with acceptable morbidity.