Surface modification of graphite encapsulated iron nanoparticles by plasma processing☆

The graphite encapsulated iron nanoparticles were fabricated by using arc dischargemethod. The synthesized nanoparticles were pre-treated by an inductively-coupled RF Ar plasma and then post-treated by NH3 plasma under various gas pressures and treatment times. Analyses of XPS spectra have been carried out to study the effect of the plasma treatment on the surface modification of nitrogen-containing groups. The morphological changes of the particles surface by plasma treatment have also been analyzed by using HR-TEM. Present results show that the highest values of N/C atomic ratio of 5.4 % is obtained by applying 10 min of Ar plasma pre-treatment and 2 min of NH3 plasma post-treatment conducted in RF power of 80W and gas pressure of 50 Pa

Plasma-activated immobilization of biomolecules onto graphite- encapsulated magnetic nanoparticles

We describe the amino group surface functionalisation of graphite-encapsulated iron compound nanoparticles by radio frequency (RF) plasma processing followed by oxidized dextran immobilization. We have found that surface treatment using plasma represents an important step before biomolecules immobilization. After plasma treatment, the dispersion property of nanoparticles in dextran solution in water was significantly improved. The successful dextran immobilization was confirmed by X-ray photoelectron spectroscopy (XPS) and high resolution-transmission electron microscopy (HR-TEM) analyses followed by amino group derivatization using 4-(trifluoromethyl)-benzaldehyde (TFBA). As an evidence for covalent bonding between nanoparticles and dextran, the area percentage of deconvoluted C N peak at ∼389.6 eV increased from 0% to 10.53 ± 1.30% with increasing the dextran concentration. The result is consistent with the evidenced decreasing of the free amino group percentage from 68.09 ± 5.10% to 14.73 ± 5.89% on the nanoparticle surface after dextran immobilization

Survival outcomes of hepatectomy for stage B Hepatocellular carcinoma in the BCLC classification

Background: Because hepatectomy is not recommended in patients with stage B hepatocellular carcinoma (HCC) of the Barcelona Clinic Liver Cancer (BCLC) staging, we evaluated the survival outcomes of hepatectomy for stage B in the BCLC system. Methods: Data were collected from 297 consecutive adult stage B patients who underwent curative hepatectomy for HCC between 1996 and 2014 in Hokkaido University Hospital. Overall survival (OS), disease-free survival (DFS), and risk factors were analyzed using the Kaplan-Meier method. Independent prognostic factors were evaluated using a Cox proportional hazards regression model. AP-factor (alpha-fetoprotein [AFP] × protein induced by vitamin K absence or antagonism factor II [PIVKA-II]) was categorized according to the serum concentrations of AFP and PIVKA-II: AP1 (AFP < 200 ng/ml and PIVKA-II < 100 mAU/ml), AP2 (AFP × PIVKA-II < 10^5), and AP3 (AFP × PIVKA-II ≥ 10^5). Results: There were 130 deaths among our 297 stage B patients (43.8%). The causes of death in these cases were HCC recurrence (n = 106; 81.5%), liver failure (n = 7; 5.4%), and other causes (n = 17; 16.1%). The operative mortality rate was 0.34% (1/297). The 5-year OS and DFS rates for the stage B cases were 54.3 and 21.9%, respectively. By multivariate analysis, tumor number and AP-factor were risk factors for both survival and recurrence that were tumor related and could be evaluated preoperatively. The study patients with stage B HCC were classified into three groups by tumor number (B1, 1; B23, 2 or 3; B4over: ≥4) and into three groups stratified by AP-factor (AP1, AP2, and AP3). The 5-year OS rates of B1, B23, and B4over were 63.6, 52.3, and 29.0%. The 5-year OS rates of AP1, AP2, and AP3 were 67.6, 65.2, and 39.1%. Stratified by the 5-year OS rate, stage B HCC patients were classified into three subgroups (A-C).The 5-year OS rates of groups A (B1 or B23 and AP-1 or AP-2), B (B1 or B23 and AP-3, or B4over and AP-1 or AP-2), and C (B4over and AP-3) were 69.5, 43.7, and 21.3%. Conclusion: Stage B HCC patients with a tumor number ≤ 3 and/or AP-factor < 1 × 10^5 show acceptable 5-year OS rates and could be treated by hepatectomy

Characteristics of direct current microhollow cathode discharges combined with dielectric barrier discharges as preionizer

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Inactivation factors of spore-forming bacteria using low-pressure microwave plasmas in an N2and O2gas mixture

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Surface Modification of Graphite-Encapsulated Iron Compound Magnetic Nanoparticles by Radio Frequency Inductively-Coupled Plasma for Biomolecules Immobilization

We&nbsp; proposed&nbsp; the&nbsp; graphite-encapsulated&nbsp; iron&nbsp; compound&nbsp; magnetic&nbsp; nanoparticles&nbsp; as&nbsp; a&nbsp; candidate&nbsp; of&nbsp; nanomaterial&nbsp; due&nbsp; to their potential properties on physical, chemical and biological fields. This study&nbsp; was performed in three steps, starting from&nbsp; the&nbsp; nanoparticle&nbsp; fabrication,&nbsp; nanoparticle&nbsp; surface&nbsp; modification&nbsp; by&nbsp; plasma&nbsp; treatment,&nbsp; leading&nbsp; to&nbsp; biomolecules immobilization for testing the treated nanoparticles capabilities. After the plasma treatment, the surface of the outmost graphene&nbsp; layer&nbsp; is&nbsp; successfully&nbsp; covered&nbsp; by&nbsp; nitrogen-containing&nbsp; groups&nbsp; definitively&nbsp; assigned&nbsp; by&nbsp; XPS&nbsp; spectra&nbsp; and&nbsp; the STEM-EDS&nbsp; elemental&nbsp; mapping.&nbsp; The&nbsp; nitrogen-containing&nbsp; groups&nbsp; formed&nbsp; during&nbsp; the&nbsp; post-treatment&nbsp; plasma&nbsp; selectively attached on the outmost of graphene layer. The inner structure of inner graphene layer and the iron core are still found in&nbsp; stable&nbsp; condition&nbsp; which&nbsp; means&nbsp; that&nbsp; the&nbsp; applied&nbsp; plasma&nbsp; condition&nbsp; allows&nbsp; the&nbsp; efficient&nbsp; covalent&nbsp; functionalization&nbsp; of nitrogen-containing group to the surface particles without give any destruction. The results shows the highest values of N/C atomic ratio of 5.4% is obtained by applying 10&nbsp; min of&nbsp; Ar plasma pre-treatment and 2&nbsp; min of NH3 plasma post-treatment conducted in RF power of 80W and gas pressure of 50 Pa. Finally, in the biomolecules section, it is found that the&nbsp; primary&nbsp; amino&nbsp; groups&nbsp; grafted&nbsp; after&nbsp; Ar&nbsp; plasma&nbsp; pre-treatment&nbsp; followed&nbsp; by&nbsp; NH3&nbsp; plasma&nbsp; post-treatment&nbsp; appeared&nbsp; to play&nbsp; an&nbsp; important&nbsp; role&nbsp; in&nbsp; dextran&nbsp; immobilization.&nbsp; The&nbsp; primary&nbsp; amines&nbsp; provide&nbsp; a&nbsp; high selective&nbsp; reaction&nbsp; between aldehyde group of oxidized dextran and amino groups of treated nanoparticles, hence the covalent immobilization was successfully&nbsp; achieved.&nbsp; The&nbsp; dextran&nbsp; immobilization&nbsp; was&nbsp; confirmed&nbsp; by&nbsp; XPS&nbsp; and&nbsp; HR-TEM&nbsp; analysis&nbsp; followed&nbsp; by&nbsp; amino group derivatization using TFBA. The deconvoluted peak at ~398.6 eV (C=N) (as an evidence for Schiff-base linkages between&nbsp; dextran&nbsp; and&nbsp; amino&nbsp; groups&nbsp; on&nbsp; the&nbsp; treated&nbsp; nanoparticles)&nbsp; increased&nbsp; with&nbsp; the&nbsp; increasing&nbsp; of&nbsp; the&nbsp; dextran concentration. This result is consistent with the decrease of free amino group percentage remaining on the nanoparticles surfaces&nbsp; which&nbsp; was evidenced when the dextran concentration increased. High&nbsp; magnification images obtained by HR-TEM allowed the visual observations of the differences between surface morphology of nanoparticles before and after dextran immobilization.Keywords: biomolecule immobilization, magnetic nanoparticles, surface modificatio

Oxygen functionalization of multiwall carbon nanotubes by Ar/H_2O plasma treatment

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Synthesis of vertically aligned carbon nanotubes on submicron-sized dot-catalyst array using plasma CVD method

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