Search Results (12)

Background: While the side-by-side stenting technique-characterized by the parallel placement of stents offers procedural simplicity, the augmented radial force exerted by the initial stent may complicate subsequent deployment. This multicenter study evaluated the practicality and safety of bilateral side-by-side stenting using novel braided self-expandable metal stents (Benefit^TM; M.I.Tech Co., Ltd., Pyeongtaek, Republic of Korea). Statistical analysis included survival analysis (Kaplan–Meier) and Cox proportional hazards regression to identify predictive factors. Patients and Methods: In this multicenter study, patients with inoperable malignant hilar biliary obstruction (Bismuth type II–IV) underwent simultaneous side-by-side endoscopic placement of two braided self-expandable metal stents. The primary outcome was stent patency. The secondary outcomes included technical and clinical success, and adverse events monitored for up to one year. Results: A total of 27 patients were included in the final analysis. The technical success rate was 92.6% (25/27), and the clinical success rate was 88.0% (22/25). The median stent patency was 93 days, with cumulative patency rates of 87.4% at 3 months and 49.7% at 12 months. Tumor ingrowth was the most common cause of stent occlusion (66.7%). Early adverse events occurred in 2 patients (one cholangitis and one stent migration), supporting the favorable safety profile of this approach. Conclusions: The simultaneous side-by-side placement of novel braided self-expandable metal stents yielded high technical success and favorable clinical outcomes in patients with inoperable malignant hilar biliary obstruction. This approach provided substantial stent patency with a low complication rate, supporting its utility as a safe and effective palliative strategy for the management of malignant hilar biliary obstruction. Full article

The lead-cooled fast reactor (LFR), a Generation IV nuclear system candidate, presents unique neutronic characteristics distinct from pressurized water reactors. Its neutron spectrum spans wider energy ranges with fast neutron dominance, exhibiting resonance phenomena across energy regions. These features require a fine energy group structure for fuel lattice calculations, significantly increasing computational demands. To balance local heterogeneity modeling with computational efficiency, researchers across the world adopt fuel assembly equivalence methods using 1D cylindrical models through volume equivalence principles. This approach enables detailed energy group calculations in simplified geometries, followed by lattice homogenization for few-group parameter generation, effectively reducing whole-core computational loads. However, limitations emerge when handling strongly heterogeneous components like structural/control rods. This study investigates the 1D equivalence method’s accuracy in lead–bismuth fast reactors under various fuel assembly configurations. Through comprehensive analysis of material distributions and their equivalence impacts, the applicability of the one-dimensional equivalence approach to fuel assemblies of different geometries and material types is analyzed in this paper. The research further proposes corrective solutions for low-accuracy scenarios, enhancing computational method reliability. This paper is significant in its optimization of the physical calculation and analysis process of a new type of fast reactor component and has important engineering application value. Full article

This study investigates the combustion characteristics of silicon-based time-delay compositions with bismuth(III) oxide (Bi₂O₃), antimony(III) oxide (Sb₂O₃), and lead(II,IV) oxide (Pb₃O₄) to identify formulations with pressure-independent burn rates. Unlike conventional pyrotechnic compositions, silicon-based mixtures offer an improved energy density and reduced sensitivity to pressure variations. The linear combustion rate of the compositions was determined for a wide range of silicon contents and for different compaction pressures. Experimental results show that burn rates range from 8 mm s⁻¹ to 195 mm s⁻¹, depending on the metal oxide type and silicon content. The highest rate (195 mm s⁻¹) was observed for Si/Pb₃O₄ at 30 wt.% silicon, while Si/Sb₂O₃ had the lowest (10 ÷ 35 mm s⁻¹). The calorimetric heat of combustion varied between 1200 J g⁻¹ and 1400 J g⁻¹, with adiabatic combustion temperatures reaching 2200 K, calculated from this heat. DTA and XRD confirmed the condensed-phase combustion, forming reduced metal phases and silicon oxides. SEM and EDS revealed a porous residue structure. This work introduces a novel approach to time-delay compositions using silicon as a primary fuel. It shows that specific silicon oxide–metal systems maintain stable combustion for different loading pressures and advance pyrotechnic formulations for safer and more efficient industrial and defense applications. Full article

Introduction: Perihilar cholangiocarcinoma is a rare malignancy of the biliary tract, for which surgery remains the treatment of choice. However, even after radical resection, the prognosis is poor. In addition to tumor size, depth of invasion and nodal/metastatic status, the TNM classification includes additional parameters such as perineural (Pn), lymphangio (L) and vascular (V) invasion. The prognostic impact of these factors is not yet fully understood. The aim of this study was to investigate the influence of these parameters on overall survival after resection of perihilar cholangiocarcinoma. Material and Methods: Data from all patients who underwent surgical exploration for perihilar cholangiocarcinoma between January 2013 and December 2023 were included into an institutional database. The impact of perineural, lymphangio and vascular invasion on overall survival was analyzed. Results: Over the 11-year period, a total of 214 patients underwent surgical exploration for perihilar cholangiocarcinoma. Curative intended resection was possible in 168 patients (78.5%). Perineural invasion, lymphangio invasion and vascular invasion were present in 79.2%, in 17.3% and in 14.3% of patients, respectively. Cross tabulation revealed a significant association between the presence of L1 and V1 (p = 0.006). There was also a significant association of Pn1, L1, and V1 with R-status (p = 0.010; p = 0.006 and p ≤ 0.001). While V1 was associated with significantly worse overall survival across the entire cohort, Pn1 alone showed only a tendency towards worse overall survival without reaching statistical significance. In Bismuth type IV, both L1 and V1, but not Pn1, were significantly associated with worse overall survival (p = 0.001; p = 0.017 and p = 0.065). Conclusions: Perineural invasion is very common in perihilar cholangiocarcinoma. Although Pn1 was associated with a tendency toward worse survival, it did not reach statistical significance. In contrast, vascular invasion significantly worsened overall survival in the entire cohort, and lymphangio invasion was linked to worse overall survival in Bismuth type IV tumors. The combination of perineural invasion with positivity of more than one additional factor (either L or V) was also associated with worse overall survival. In patients with Bismuth type IV, these pathological markers appeared to have even greater prognostic relevance. Full article

Background: In Bismuth type III and IV Hilar Cholangiocarcinoma (III–IV HC), surgical resection is the only chance for long-term survival. As the surgical procedure is complex and Robotic-Assisted Surgery (RAS) may be particularly suitable in this setting, the aim of this study is to evaluate the potential benefits of RAS in III–IV HC in terms of post-operative outcomes. Methods: We conducted a systematic review using the PRISMA checklist for article selection. We searched the PubMed database and included only studies with clinical data about the treatment of III–IV HC using RAS. Results: A total of 12 papers involving 50 patients were included. All cases were Bismuth IIIa (n = 18), IIIb (n = 27) or IV type (n = 5) and underwent hepatectomy with biliary confluence resection and reconstruction. The mean operative time was 500 minutes with a conversion rate of 4%. The mean hospital stay was 12.2 days, and the morbidity and 30-day mortality rate were 61.9% and 2%, respectively. Over a mean follow up period of 10.1 months, 9/18 cases experienced recurrence (50%). Conclusions: RAS for III–IV HC is safe and feasible, at least if performed by experienced surgeons on selected cases. The oncological outcomes appear acceptable, given the aggressiveness of this pathology, but further studies are needed to fully elucidate the exact role of robotics in this setting. Full article

Stent implantation is an effective approach for palliative treatment of Bismuth-Corlette type III–IV malignant hilar biliary obstructions (MHBOs). In this article, we reviewed the currently used access methods for biliary stent placement (percutaneous transhepatic biliary drainage, endoscopic biliary drainage, endosonography guided biliary drainage), the available stent types (plastic stent, self-expanding metallic stent, full cover self-expanding metallic stent, radioactive self-expanding metallic stent), major approaches (unilateral, bilateral) and deployment methods (stent-in-stent, stent-by-stent). Finally, this review gives an outlook on perspectives of development in stenting and other palliative methods in MHBO. Full article

A fully automated experimental system was designed for simultaneous measurement of the Seebeck coefficient and electrical resistivity of thermoelectric materials in bulk form. The system incorporates a straightforward and easily fabricated sample holder along with commercially available electronic instrument components. The sample holder showcases a compact design that utilizes two Peltier module heaters to induce sample heating and generate the required temperature gradient. System automation and control are achieved through the implementation of a LabView program. The Seebeck voltage and resistance of the sample (under specified temperature conditions) are determined using I–V measurements. The Seebeck voltage and resistance of the sample correspond to the intercept and slope of the I–V characteristic diagram in the four-point probe method, respectively. To verify the accuracy and reliability of the developed apparatus, a variety of experiments were performed on N-type and P-type bismuth telluride samples. The measurement results closely matched those obtained from commercial systems, with an overall data difference of less than 10% for both the Seebeck coefficient and resistivity measurements. Full article

How the side of an extended liver resection impacts the postoperative prognosis of advanced perihilar cholangiocarcinoma (PHC) is still controversial. We compared the outcomes of right (RTS) and left trisectionectomies (LTS) in Bismuth-Corlette (BC) type IV PHC resection. All patients undergoing RTS or LTS for BC type IV PHC in a single tertiary center between January 2012 and December 2019 were compared retrospectively. The endpoints were perioperative outcomes, long-term overall (OS), and disease-free survival (DFS). Among 67 hepatic resections for BC type IV PHC, 25 (37.3%) were LTS and 42 (63.7%) were RTS. Portal vein and artery resection rates were 40% and 52.4% (p = 0.29), and 24% and 0% (p < 0.001) in the LTS and RTS groups, respectively. The severe complication (Clavien–Dindo > IIIa) rate was comparable (36% vs. 21.5%, p = 0.357) while the postoperative liver failure (POLF) rate was lower in the LTS group (16% vs. 38%, p = 0.048). The R0 resection rate was similar between groups (81% vs. 92%; p = 0.154). The five-year OS rate was higher in the LTS group (66% vs. 30%, p = 0.009) while DFS was comparable (43% vs. 18%, p = 0.11). Based on multivariable analysis, the side of the trisectionectomy was an independent predictor of OS. Compared with RTS, LTS is associated with lower POLF and higher overall survival despite more frequent arterial reconstructions in type IV PHC. Although technically more demanding, LTS may be preferred in the treatment of advanced PHC. Full article

Complete resection of perihilar cholangiocarcinoma (pCCA) is the only potentially curative treatment. Long-term survival data is rare and prognostic analyses are hindered by the rarity of the disease. This study aimed to determine the cure rate and to identify clinicopathological factors that may preclude cure. All consecutive resections for pathologically confirmed pCCA between 2000 and 2009 in 22 centers worldwide were included in a retrospective cohort study. Each center included its retrospective data series. A total of 460 patients were included with a median follow-up of 10 years for patients alive at last follow-up. Median overall survival (OS) was 29.9 months and 10-year OS was 12.8%. Twenty-nine (6%) patients reached 10-year OS. The observed cure rate was 5%. Factors that virtually precluded cure (i.e., below 1%) according to the mixture cure model included age above 70, Bismuth-Corlette type IV tumors, hepatic artery reconstruction, and positive resection margins. Cure was unlikely (i.e., below 3%) in patients with positive lymph nodes or poor tumor differentiation. These factors need to be considered in patient counseling and long-term follow-up after surgery. Full article

An occurrence of vein U-Mo mineralization is located in the Majerská valley near Čučma, about 7 km to the NNE of the district town of Rožňava (Eastern Slovakia). Mineralization is hosted in the acidic metapyroclastics of the Silurian Bystrý Potok Fm. (Gemeric Unit), and originated in the following stages: (I.) quartz I, fluorapatite I; (II.) quartz II, fluorapatite II, zircon, rutile chlorite, tourmaline; (III.) uraninite, molybdenite, U-Ti oxides; (IV.) pyrite I, ullmannite, gersdorffite, cobaltite; (Va.) galena, bismuth, tetradymite, joséite A and B, Bi₃(TeS)₂ mineral phase, (BiPb)(TeS) mineral phase, ikunolite; (Vb.) minerals of the kobellite–tintinaite series, cosalite; (VI.) pyrite II; (VII.) titanite, chlorite; and (VIII.) supergene mineral phases. The chemical in-situ electron-microprobe U-Pb dating of uraninite from a studied vein yielded an average age of around 265 Ma, corresponding to the Guadalupian Epoch of Permian; the obtained data corresponds with the age of Gemeric S-type granites. The age correlation of uraninite with the Gemeric S-type granites and the spatial connection of the studied mineralization with the Čučma granite allows us to assume that it is a Hercynian, granite-related (perigranitic) mineralization. Full article

Background: Heavy metals are known to be harmful for neurodevelopment and they may correlate to attention deficit/hyperactivity disorder (ADHD). In this study, we aim to explore the relationships between multiple heavy metals (manganese, lead, cadmium, mercury, antimony, and bismuth), neurocognitive function, and ADHD symptoms. Methods: We recruited 29 patients with ADHD inattentive type (ADHD-I), 47 patients with ADHD hyperactivity/impulsivity type (ADHD-H/I), and 46 healthy control children. Urine samples were obtained to measure the levels of the aforementioned heavy metals in each child. Participants’ cognitive function and clinical symptoms were assessed, respectively. Results: We found ADHD-H/I patients demonstrated the highest antimony levels (p = 0.028), and ADHD-I patients demonstrated the highest cadmium levels (p = 0.034). Antimony levels were positively correlated with the severity of ADHD symptoms that were rated by teachers, and cadmium levels were negatively correlated with the Full Scale Intelligence Quotient. Lead levels were negatively correlated with most indices of the Wechsler Intelligence Scale for Children–Fourth Edition (WISC-IV), but positively correlated with inattention and hyperactivity/impulsivity symptoms (p < 0.05). Conclusion: Lead, cadmium and antimony were associated with susceptibility to ADHD and symptom severity in school-age children. Eliminating exposure to heavy metals may help to prevent neurodevelopmental disorders in children. Full article

In this work, a Bi-Te-Ni-Fe complex coating material was obtained on magnesium oxide substrate by a single step ambient pressure chemical vapor deposition (CVD). Nickel acetate, bismuth acetate, iron (III) nitrate, and tellurium (IV) chloride dissolved in N,N-dimethylformamide (DMF) served as the metal sources for Ni, Bi, Fe, and Te, respectively. Hydrogen was used as the carrier gas. The substrate was kept at 500 °C in a quartz tube reaction chamber. The chemical vapor deposition time was two hours. Scanning electron microscopic observation revealed porous morphology of the deposited material with a needle-like submicron fine structure. These needle-like entities form networks with fairly uniform distribution on the substrate. Thermoelectric property test showed that the coating is p-type with a Seebeck coefficient of 179 µV/K. Time-dependent potential data were obtained to show the sensitivity of the Seebeck effect to temperature changes. Full article