Search Results (22)

The structure and magnetic properties of Sm_6−xLa_xMn₂₃ (x = 0.5, 1, 2, 3 and 4) alloys have been studied systematically. We found that the Th₆Mn₂₃-type Sm_6−xLa_xMn₂₃ alloys become less stable with increasing La content, and α-Mn becomes the dominant phase at x = 4. More impurities were found to present in Sm₅LaMn₂₃ samples prepared by a rapid solidification process than those present in the as-cast ingots. The coercivity of Sm₄La₂Mn₂₃ induction-melted ingots and Sm₅LaMn₂₃ melt-spun ribbons reached up to 0.47 T and 0.53 T, respectively, indicating potential applications of this alloy in hard magnetic materials. The Curie temperature of Sm_6−xLa_xMn₂₃ falls in the range of 398 K for x = 1 to 438 K for x = 3. The La-substitution results in a reduced saturation magnetization of Sm_6−xLa_xMn₂₃, owing to a reduced total-magnetic-moment contribution of the Sm-sublattices. This work provides us a deeper understanding of the effect of La-substitution on the structure and magnetic properties of the ternary La-Sm-Mn alloys. Full article

Background: Low-grade appendiceal mucinous neoplasms (LAMNs) are rare lesions of the vermiform appendix and characterized by mucinous epithelial proliferation, extracellular mucin, and the absence of destructive invasion. Appendiceal diverticulum (AD) is also an uncommon condition that may be challenging to differentiate from acute appendicitis when it is superimposed by diverticulitis or perforation. Some recently published studies emphasized that complicated AD with mucosal hyperplasia can be confused with LAMNs, leading to overdiagnosis. The present study aimed to determine the histopathological features which can be used in the differential diagnosis of LAMNs and ADs, particularly complicated diverticula, in a large cohort. Methods: Cases comprising LAMNs and ADs diagnosed between 2011 and 2021 were included in the study. All cases were evaluated for the epithelial lining, the wall of the lesions, and the presence of cellular or acellular mucin, with its localization in terms of level and site of involvement within the appendix also recorded. Results: The hypermucinous epithelium characteristic of LAMNs, fibrosis, and calcification in the wall and the absence of lamina propria and muscularis mucosa proved to be the most discriminatory features in the differential diagnosis of LAMNs and ADs. Conclusions: The distinction between mucinous neoplasia and its mimics is critically important, since mucinous neoplasia requires surveillance imaging and potential surgery or chemotherapy depending on the extent of the disease, whereas non-neoplastic lesions are treated by an appendectomy and require no future intervention or surveillance. Full article

We report a rare case of low-grade appendiceal mucinous neoplasm (LAMN) causing ileocolic intussusception. The case underscores the importance of considering ileocolic intussusception in differential diagnoses for nonspecific gastrointestinal symptoms. Early diagnosis via contrast-enhanced CT and scrupulous surgical intervention are crucial for favorable outcomes. Full article

Metal oxides containing La, Mn, and Co cations can catalyze oxygen reduction reactions (ORRs) in electrochemical processes. However, these materials require carbon support and optimal interactions between both compounds to be active. In this work, two approaches to prepare composites of La-Mn-Co-based compounds over carbon xerogel were developed. Using sol-gel methods, either the metal-based material was deposited on the existing carbon xerogel or vice versa. The metal oxide selected was the LaMn_0.7Co_0.3O₃ perovskite, which has good catalytic behavior and selectivity towards direct ORRs. All the as-prepared composites were tested for ORRs in alkaline liquid electrolytes and characterized by diverse physicochemical techniques such as XRD, XPS, SEM, or N₂ adsorption. Although the perovskite structure either decomposed or failed to form using those in situ methods, the materials exhibited great catalytic activity, which can be ascribed to the strengthening of the interactions between oxides and the carbon support via C-O-M covalent bonds and to the formation of new active sites such as the MnO/Co heterointerfaces. Moreover, Co-N_x-C species are formed during the synthesis of the metal compounds over the carbon xerogel. These species possess a strong catalytic activity towards ORR. Therefore, the composites formed by synthesizing metal compounds over the carbon xerogel exhibit the best performance in the ORR, which can be ascribed to the presence of the MnO/Co heterointerfaces and Co-N_x-C species and the strong interactions between both compounds. Moreover, the small nanoparticle size leads to a higher number of active sites available for the reaction. Full article

Second-life applications for lithium-ion batteries offer the industry opportunities to defer recycling costs, enhance economic value, and reduce environmental impacts. An accurate prognosis of the remaining useful life (RUL) is essential for ensuring effective second-life operation. Diagnosis is a necessary step for the establishment of a reliable prognosis, based on the aging modes involved in a cell. This paper introduces a method for characterizing specific aging phenomenon in Graphite/Lithium Iron Phosphate (G/LFP) cells. This method aims to identify aging related to the loss of active material at the negative electrode (LAM_NE). The identification and tracking of the state of health (SoH) are based on Incremental Capacity Analysis (ICA) and Differential Voltage Analysis (DVA) peak-tracking techniques. The remaining capacity of the electrode is thus evaluated based on these diagnostic results, using a model derived from half-cell electrode characterization. The method is used on a G/LFP cell in the format 18650, with a nominal capacity of 1.1 Ah, aged from its pristine state to 40% of state of health. Full article

There is no clear evidence on the prevalence and clinical presentation of appendiceal mucinous neoplasm (AMN) among patients with inflammatory bowel disease (IBD), so a systematic review was performed to investigate the diagnosis, management and treatment of AMN in these patients. PubMed, Medline, Scopus and the Cochrane Library were searched for articles published up to September 2023. Twenty-three studies reporting data about 34 AMN patients were included. UC patients had a median age of 52 years and a median length of disease of 10 years; CD patients had a median age of 40.5 years and a median length of disease of 5 years. A pre-operative diagnosis was achieved in 44% of patients. Most patients were symptomatic (82.6%) and showed moderate–severe disease activity (61%). Surgical procedures were performed: laparoscopic appendectomy, ileocecal resection, right hemicolectomy and colectomy/proctocolectomy. Of the patients, 73.5% were diagnosed with low-grade mucinous neoplasm (LAMN) and nine with adenocarcinoma. Synchronous colorectal dysplasia/carcinoma was present in 23.5% of patients. IBD patients with long-standing disease should be routinely screened, not only for colorectal cancer but also for AMN, during gastro-enterologic follow-up. Laparoscopic appendectomy of unruptured LAMN as well as right hemicolectomy of non-metastatic adenocarcinoma are safe procedures in IBD patients. Full article

Patients with low-grade appendiceal mucinous carcinomas (LAMNs) treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have a favorable prognosis. However, a subgroup of patients presents a clinically aggressive course with disease progression despite receiving treatment. The purpose of this study is to report the experience of clinically aggressive LAMN patients treated by the same team, and to present a review of the literature. The cases of four patients with clinically aggressive LAMNs were reviewed. Clinical and histopathological characteristics were re-examined. Recurrences and the time of recurrence, as well as the survival time, were recorded. These patients were four men with clinically aggressive LAMNs treated with CRS plus HIPEC. One of them underwent CC-0 surgery, two underwent CC-1 surgery, and one underwent CC-3 surgery. All patients received systemic chemotherapy after surgery. Recurrence was recorded in three of the patients within 4–23 months after the initial treatment. Two of the patients underwent secondary CRS. Three patients died of disease recurrence within 13–23 months, and one is alive with a disease relapse at 49 months after his initial surgery. LAMNs were identified in both the initial specimens and the specimens obtained during reoperation. The prognosis of LAMN patients treated with CRS plus HIPEC is favorable. A small number of patients present a clinically aggressive course that is unresponsive to any treatment. Molecular and genetic studies are required to identify this group of LAMN patients who have an unfavorable prognosis. Full article

Perovskite SCR catalysts have become a hot research topic in the field of de-NO_x catalyst development. This article selects LaMnO₃ with high performance as the research object, modifies the catalyst by doping some iron elements instead of manganese elements, and applies density functional theory to study its reaction mechanism, providing theoretical reference for further research on perovskite. Research has found that several main reactants such as NH₃, NO, and O₂ can form stable adsorption at the active site, with NO more inclined to adsorb at the nitrogen atom end at the active site. The oxidation of O₂ molecules after adsorption is greater than that of the active site. The adsorption capacity of the Mn active site of the catalyst before modification on the above molecules is weaker than that of the Fe active site introduced after modification. Under both anaerobic and aerobic conditions in the SCR reaction process, NH₃ molecules are first adsorbed at the active site, and then influenced by lattice oxygen under anaerobic conditions. Under aerobic conditions, they are gradually dehydrogenated and produce NH₂ and NH radicals. These two radicals react with NO molecules to form intermediate products in the form of NH₂NO and NHNO molecules. Due to the instability of the intermediate products, they ultimately decompose into N₂ and H₂O molecules. The introduction of Fe active sites can increase the generation of NH₂ and NH radicals during the reaction process and simplify the reaction process between NH₂ radicals and NO molecules, which will be conducive to the completion of the reaction. Full article

The inclusion of La-Mn vacancies in LaMnO₃ nanoparticles leads to a noticeable change in conductivity behavior. The sample retains its overall insulator characteristic, with a typical thermal activation mechanism at high temperatures, but it presents high magnetoconductivity below 200 K. The activation energy decreases linearly with the square of the reduced magnetization and vanishes when the sample is magnetized at saturation. Therefore, it turns out that electron hopping between Mn³⁺ and Mn⁴⁺ largely contributes to the conductivity below the Curie temperature. The influence of the applied magnetic field on conductivity also supports the hypothesis of hopping contribution, and the electric behavior can be explained as being due to an increase in the hopping probability via spin alignment. Full article

Background: Pseudomyxoma peritonei (PMP) is a rare peritoneal condition where mucus-secreting tumorous cells progressively produce a thick, gelatin-like substance. The prognosis of patients with PMP is determined by the degree of cellularity within the mucin (low-grade (LAMN) vs. high-grade (HAMN) histologic features) and by the extent of the disease. Methods: Prognostic relevance of tumor markers CA19-9 and CEA, gender, Peritoneal Cancer Index (PCI), and completeness of cytoreduction (CC) after cytoreductive surgery were evaluated on 193 consecutive PMP patients, based on a retrospective analysis of prospectively gathered data from a German tertial referral center. Results: We demonstrated that low PCI, CC0 status, low-grade histology, and female gender were independent positive prognostic factors for both overall survival (OS) and progression-free survival (PFS). Furthermore, LAMN patients with achieved CC0 status show significantly better OS and PFS compared to those with CC1 status (p = 0.0353 and p = 0.0026 respectively). In contrast, the duration and drug of hyperthermic intraperitoneal chemotherapy (HIPEC) were not prognostic in any comparison. Increased CA19-9 and CEA levels were significantly associated with HAMN cases, but also predicted recurrence in patients with low-grade histologies. Conclusion: Our study confirmed the prognostic role of tumor markers and emphasized the importance of CC status and PCI in a large cohort of PMP- and LAMN patients. Full article

Aim: Pseudomyxoma peritonei (PMP) is an uncommon pathology, and its rarity causes a lack of scientific evidence, precluding the design of a prospective trial. A diagnostic and therapeutic algorithm (DTA) is necessary in order to standardize the disease treatment while balancing optimal patient management and the correct use of resources. The Consensus of the Italian Society of Surgical Oncology (SICO) Oncoteam aims at defining a diagnostic and therapeutic pathway for PMP and appendiceal primary tumors applicable in Italian healthcare. Method: The consensus panel included 10 delegated representatives of oncological referral centers for Peritoneal Surface Malignancies (PSM) affiliated to the SICO PSM Oncoteam. A list of statements regarding the DTA of patients with PMP was prepared according to recommendations based on the review of the literature and expert opinion. Results: A consensus was obtained on 33 of the 34 statements linked to the DTA; two flowcharts regarding the management of primary appendiceal cancer and peritoneal disease were approved. Conclusion: Currently, consensus has been reached on pathological classification, preoperative evaluation, cytoreductive surgery technical detail, and systemic treatment; some controversies still exist regarding the exclusion criteria for HIPEC treatment. A shared Italian model of DTA is an essential tool to ensure the appropriateness and equity of treatment for these patients. Full article

The occurrence of fluoride contamination in drinking water has gained substantial concern owing to its serious threat to human health. Traditional adsorbents have shortcomings such as low adsorption capacity and poor selectivity, so it is urgent to develop new adsorbents with high adsorption capacity, renewable and no secondary pollution. In this work, magnetic electrospun La-Mn-Fe tri-metal oxide nanofibers (LMF NFs) for fluoride recovery were developed via electrospinning and heat treatment, and its defluoridation property was evaluated in batch trials. Modern analytical tools (SEM, BET, XRD, FTIR) were adopted to characterize the properties of the optimized adsorbent, i.e., LMF11 NFs with a La:Mn molar ratio of 1:1. The surface area calculated via BET method and pH_pzc assessed using pH drift method of LMF11 NFs were 55.81 m² g⁻¹ and 6.47, respectively. The results indicated that the adsorption amount was highly dependent on the pH of the solution, and reached the highest value at pH = 3. The kinetic behavior of defluoridation on LMF11 NFs was dominated by the PSO model with the highest fitted determination coefficients of 0.9999. Compared with the other three isotherm models, the Langmuir model described defluoridation characteristics well with larger correlation coefficients of 0.9997, 0.9990, 0.9987 and 0.9976 at 15 °C, 25 °C, 35 °C and 45 °C, respectively. The optimized LMF11 NFs exhibited superior monolayer defluoridation capacities for 173.30–199.60 mg F⁻/g at pH 3 at 15–45 °C according to the Langmuir isotherm model. A thermodynamic study proved that the defluoridation by LMF11 NFs is a spontaneous, endothermic along with entropy increase process. In addition, the LMF11 NFs still showed high defluoridation performance after three reused cycles. These findings unveil that the synthesized LMF11 NFs adsorbent is a good adsorbent for fluoride remediation from wastewater owing to its low cost, high defluoridation performance and easy operation. Full article

Perovskite samples of the LaMn_1−xFe_xO₃ (x = 0–1) series were prepared by the Pechini method; their physicochemical properties were studied using XRD, HRTEM, XPS, and BET, and their catalytic activity was estimated in nitrous oxide decomposition and methane and CO oxidation reactions. In methane and CO oxidation reactions, all intermediate (0 < x < 1) samples of the series exhibited a lower catalytic activity normalized to the unit surface area as compared to the extreme terms, whereas in the nitrous oxide decomposition all intermediate samples were more active than extreme terms of the series. Different dependences of activities on the composition obtained in the study for the tested reactions involving the catalyst oxygen are caused by differences in the reaction mechanisms. Full article

Patients treated surgically for local non-invasive mucinous appendiceal neoplasm (NI-MAN) may recur with the development of peritoneal dissemination (PD). The risk of recurrence and predictive factors are not well studied. Patients with NI-MAN, with or without peritoneal dissemination at presentation, were included. Patients with limited disease underwent surgical resection only. Patients with peritoneal dissemination underwent cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy (HIPEC). Patients without PD (nPD) were compared to those who presented with PD. Thirty-nine patients were included, 25 in nPD and 14 in PD. LAMN was diagnosed in 96% and 93% of patients in nPD and PD, respectively. Acellular mucin on the peritoneal surface was seen in 16% of nPD patients vs. 50% of PD patients (p = 0.019). Two (8%) patients in the nPD group who had LAMN without wall rupture recurred, at 57 and 68 months, with a PCI of 9 and 22. The recurrence rate in the PD group was 36%. All recurred patients underwent CRS+HIPEC. A peritoneal recurrence is possible in NI-MANs confined to the appendix even with an intact wall at initial diagnosis. The peritoneal disease may occur with significant delay, which is longer than a conventional follow-up. Full article

Catalysts based on perovskite—fluorite nanocomposites with supported nickel 5%Ni/[Pr_0.15Sm_0.15Ce_0.35Zr_0.35O₂ + LaMn_0.9Ru_0.1O₃] were synthesized by three different methods. Structural and surface features of as-prepared samples were elucidated by N₂ adsorption, XRD, HR TEM with EDX; reducibility and reactivity were estimated by H₂-TPR, and catalytic properties were studied in ethanol steam reforming in the 500–700 °C temperature range. The best catalytic activity without coke accumulation was demonstrated for the 5%Ni/[Pr_0.15Sm_0.15Ce_0.35Zr_0.35O₂+ LaMn_0.9Ru_0.1O₃] catalyst with nanocomposite support obtained by a simple sequential polymeric preparation method. Highly dispersed particles of metallic nickel strongly fixed on the support after the reaction were shown by the HR-TEM and H₂ –TPR data. The catalyst provides stable full conversion of ethanol and hydrogen yield above 60% at 600 °C for at least 6 h. Full article