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argon plasma

Stefania Chetcuti Zammit, Reena Sidhu
PURPOSE OF REVIEW: The objective is to provide an overview on the cause of small bowel bleeding. We discuss the role of small bowel endoscopy in the management of small bowel bleeding and provide an outline of pharmacotherapy that can be additionally beneficial. RECENT FINDINGS: Small bowel capsule endoscopy (SBCE) is the initial diagnostic investigation of choice in small bowel bleeding. Computed tomography (CT) can be helpful in the context of small bowel tumours...
March 7, 2018: Current Opinion in Gastroenterology
Pieter Cools, Mahtab Asadian, Wannes Nicolaus, Heidi Declercq, Rino Morent, Nathalie De Geyter
This work describes the surface modification of 300PEO-PEOT/PBT 55/45 thin films using a medium pressure dielectric barrier discharge system operated in argon, helium, nitrogen or dry air to improve cell-surface interactions of this established biomaterial. The first part of the paper describes the optimization of the plasma processing parameters using water contact angle goniometry. The optimized samples are then characterized for changes in surface topography and surface chemical composition using atomic force microscopy (AFM) and X-ray fluorescence spectroscopy (XPS) respectively...
March 7, 2018: Materials
Praneet Wander, Daniel Castaneda, Lionel D'Souza, Simi Singh, Sam Serouya, Ana I Velazquez, Rifat Mamun, Rebecca Voaklander, Petros Benias, David L Carr-Locke
BACKGROUND: To assess the safety and efficacy of the Instinct clip in the acute endoscopic treatment of upper gastrointestinal bleeding (UGIB). MATERIALS AND METHODS: This is the first large series reporting this clip in achieving hemostasis. A retrospective descriptive chart review was performed on patients presenting with recent overt GI bleeding treated with endoclip therapy at Mount Sinai Beth Israel Medical Center between May 2013 and January 2016. Results are expressed in absolute numbers, percentages, and trends...
April 2018: Journal of Clinical Gastroenterology
Matthias H M Klose, Sarah Theiner, Christoph Kornauth, Samuel M Meier-Menches, Petra Heffeter, Walter Berger, Gunda Koellensperger, Bernhard K Keppler
Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to study the spatial distribution of two metallodrugs with anticancer activities in vivo, namely the organoruthenium plecstatin-1 (1) and its isosteric osmium analogue (2), in liver, kidneys, muscles and tumours of treated mice bearing a CT-26 tumour after single-dose i.p. administration. To the best of our knowledge, this is the first time that the spatial distribution of an osmium drug candidate has been investigated using LA-ICP-MS in tissues...
March 7, 2018: Metallomics: Integrated Biometal Science
Jakub Jadwiszczak, Colin O'Callaghan, Yangbo Zhou, Daniel S Fox, Eamonn Weitz, Darragh Keane, Conor P Cullen, Ian O'Reilly, Clive Downing, Aleksey Shmeliov, Pierce Maguire, John J Gough, Cormac McGuinness, Mauro S Ferreira, A Louise Bradley, John J Boland, Georg S Duesberg, Valeria Nicolosi, Hongzhou Zhang
Precise tunability of electronic properties of two-dimensional (2D) nanomaterials is a key goal of current research in this field of materials science. Chemical modification of layered transition metal dichalcogenides leads to the creation of heterostructures of low-dimensional variants of these materials. In particular, the effect of oxygen-containing plasma treatment on molybdenum disulfide (MoS2 ) has long been thought to be detrimental to the electrical performance of the material. We show that the mobility and conductivity of MoS2 can be precisely controlled and improved by systematic exposure to oxygen/argon plasma and characterize the material using advanced spectroscopy and microscopy...
March 2018: Science Advances
Han Qi, Zhongwu Li, Yi Tao, Weiwei Zhao, Kabin Lin, Zhenhua Ni, Chuanhong Jin, Yan Zhang, Kedong Bi, Yunfei Chen
The ability to sieve ions through nanopores with high throughput has significant importance in seawater desalination and other separation applications. In this study, a plasma etching process has been demonstrated to be an efficient way to produce high-density nanopores on graphene membranes with tunable size in the sub-nanometer range. Besides the pore size, the nanopore density is also controllable through adjusting the exposure time of the sample to argon or oxygen plasma. The plasma-treated graphene membranes can selectively transport protons, Na+ and Cl- ions...
March 6, 2018: Nanoscale
Paul St Romain, Amanda Boyd, Jiayin Zheng, Shein-Chung Chow, Rebecca Burbridge, Daniel Wild
Introduction and study aims:  Gastric antral vascular ectasia (GAVE) is a mucosal abnormality associated with multiple conditions, most notably cirrhosis and systemic sclerosis, that causes indolent gastrointestinal bleeding. It is primarily managed with endoscopic therapy. Traditionally, GAVE is endoscopically ablated using argon plasma coagulation (APC) but radiofrequency ablation (RFA) is emerging as an alternative modality. No prior comparison of the 2 modalities has been published...
March 2018: Endoscopy International Open
Jing Hu, Ralph E Sturgeon, Kenny Nadeau, Xiandeng Hou, Chengbin Zheng, Lu Yang
A novel, reliable, and sensitive approach for the determination of chlorine by sector field inductively coupled plasma mass spectrometry (SF-ICPMS) using photochemical vapor generation for sample introduction is presented. Methyl chloride is generated from different chlorine species in a flow-through photochemical reactor using a 1% solution of acetic acid containing 7.5 μg g-1 of Cu2+ . The volatile product is directed by an argon carrier gas to a gas-liquid separator and introduced into the instrument. A sample flow rate at 1...
March 1, 2018: Analytical Chemistry
Alexander Schütz, Felipe J Lara-Ortega, Felix David Klute, Sebastian Brandt, Michael Schilling, Antje Michels, Damir Veza, Vlasta Horvatic, Juan F Garcia-Reyes, Joachim Franzke
Dielectric barrier discharges (DBDs) have been used as soft ionization sources (DBDI) for organic mass spectrometry (DBDI-MS) for approximately ten years. Helium-based DBDI is often used because of its good ionization efficiency, low ignition voltage and homogenous plasma conditions. Argon needs much higher ignition voltages than helium when the same discharge geometry is used. A filamentary plasma, which is not suitable for soft ionization, may be produced instead of a homogenous plasma. This difference results in N2, present in helium and argon as an impurity, being Penning-ionized by helium but not by metastable argon atoms...
February 20, 2018: Analytical Chemistry
Luigi Canullo, Marco Tallarico, Daniele Botticelli, Karol Alí Apaza Alccayhuaman, Evandro Carneiro Martins Neto, Samuel Porfirio Xavier
OBJECTIVE: To histologically assess the hard and soft tissue changes after insertion of cleaned and activated titanium implants using plasma of argon. MATERIALS AND METHODS: Eight dogs were included in this study. The mandibular premolars and first molars were extracted. For each hemi-mandible, four implants, 7 mm long and 3.3 mm of diameter, with a ZirTi surface were used. The surface of two implants was randomly treated with argon plasma (test), while the other two implants were left untreated (control)...
February 16, 2018: Clinical Oral Implants Research
Marco Antonio Ridenti, Jayr de Amorim, Arnaldo Dal Pino, Vasco Guerra, George Petrov
In this work we compute the main features of a surface-wave-driven plasma in argon at atmospheric pressure in view of a better understanding of the contraction phenomenon. We include the detailed chemical kinetics dynamics of Ar and solve the mass conservation equations of the relevant neutral excited and charged species. The gas temperature radial profile is calculated by means of the thermal diffusion equation. The electric field radial profile is calculated directly from the numerical solution of the Maxwell equations assuming the surface wave to be propagating in the TM_{00} mode...
January 2018: Physical Review. E
Pavla Zurynková, Jiří Dědina, Jan Kratzer
Atomization conditions for antimony hydride in the plasma atomizer based on a dielectric barrier discharge (DBD) with atomic absorption spectrometric detection were optimized. Argon was found as the best discharge gas under a flow rate of 50 mL min - 1 while the DBD power was optimum at 30 W. Analytical figures of merit including interference study of As, Se and Bi have been subsequently investigated and the results compared to those found in an externally heated quartz tube atomizer (QTA). The limit of detection (LOD) reached in DBD (0...
June 20, 2018: Analytica Chimica Acta
Ashwin Ambi, Nisharg Parikh, Carolina Vera, Krystal Burns, Naidel Montano, Leonard Sciorra, Jessica Epstein, Debing Zeng, Christian Traba
Many research groups have attained slow, persistent, continuous release of silver ions through careful experimental design using existing methods. Such methods effectively kill planktonic bacteria and therefore prevent surface adhesion of pathogens. However, the resultant modified coatings cannot provide long-term antibacterial efficacy due to sustained anti-microbial release. In this study, the anti-infection activity of AgNP immobilized biomaterials was evaluated, facilitated by argon plasma grafting technology and activated by bacterial colonization...
February 15, 2018: Biofouling
Pankaj Attri, Fumiyoshi Tochikubo, Ji Hoon Park, Eun Ha Choi, Kazunori Koga, Masaharu Shiratani
The rapid growth in world population brings with it the need for improvement in the current technology for water purification, in order to provide adequate potable water to everyone. Although an advanced oxidation process has been used to purify wastewater, its action mechanism is still not clear. Therefore, in the present study we treat dye-polluted water with gamma rays and dielectric barrier discharge (DBD) plasma. We study the wastewater treatment efficiency of gamma rays and DBD plasma at different absorbed doses, and at different time intervals, respectively...
February 13, 2018: Scientific Reports
Kazunori Takahashi, Christine Charles, Rod Boswell, Akira Ando
A specially constructed experiment shows the near perfect adiabatic expansion of an ideal electron gas resulting in a polytropic index greater than 1.4, approaching the adiabatic value of 5/3, when removing electric fields from the system, while the polytropic index close to unity is observed when the electrons are trapped by the electric fields. The measurements were made on collisionless electrons in an argon plasma expanding in a magnetic nozzle. The collision lengths of all electron collision processes are greater than the scale length of the expansion, meaning the system cannot be in thermodynamic equilibrium, yet thermodynamic concepts can be used, with caution, in explaining the results...
January 26, 2018: Physical Review Letters
Semra Bilaçeroğlu
Endobronchial ablative therapies, such as mechanical debulking, laser therapy, electrocautery, argon plasma coagulation, cryotherapy, brachytherapy, photodynamic therapy, microdebrider bronchoscopy, resector balloon deobstruction, and intratumoral chemotherapy, are performed through a rigid or flexible bronchoscope in palliating or curing symptomatic malignant and benign airway lesions to improve symptoms, quality of life, and survival. Technical factors together with patient- and lesion-specific features determine the therapy of choice, as each therapy is different in capacity, limitation, and complications...
March 2018: Clinics in Chest Medicine
Daniela Guerrero Vinsard, Pujan Kandel, Lady Katherine Mejia Perez, Russell L Bingham, Ryan J Lennon, Timothy A Woodward, Victoria Gomez, Massimo Raimondo, Ernest P Bouras, Michael B Wallace
Background and study aims:  Risk factors for colorectal adenoma recurrence after endoscopic mucosal resection (EMR) have been well documented. We assessed the efficacy of the newer 190 colonoscope versus the standard 180 colonoscope for complete resection of lateral spreading lesions. Patients and methods:  A single-center, retrospective study of patients who underwent EMR with Olympus 180 or 190 colonoscopes from January 1, 2010 to September 30, 2016. We included patients with lesions ≥ 20 mm and surveillance colonoscopy (SC1) after index EMR...
February 2018: Endoscopy International Open
Lavanya Jothi, Sudarsan Neogi, Saravana Kumar Jaganathan, Gomathi Nageswaran
A novel nitrogen/argon (N2/Ar) radio frequency (RF) plasma functionalized graphene nanosheet/graphene nanoribbon (GS/GNR) hybrid material (N2/Ar/GS/GNR) was developed for simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Various nitrogen mites introduced into GS/GNR hybrid structure was evidenced by a detailed microscopic, spectroscopic and surface area analysis. Owing to the unique structure and properties originating from the enhanced surface area, nitrogen functional groups and defects introduced on both the basal and edges, N2/Ar/GS/GNR/GCE showed high electrocatalytic activity for the electrochemical oxidations of AA, DA, and UA with the respective lowest detection limits of 5...
May 15, 2018: Biosensors & Bioelectronics
Maged F Bekheet, Lukas Schlicker, Andrew Doran, Konrad Siemensmeyer, Aleksander Gurlo
Stoichiometric (MnGa2O4 and MnAl2O4) and Mn-rich (Mn1.3Ga1.7O4 and Mn1.4Al1.6O4) spinels with a small inversion degree (0.14-0.21) were obtained via a co-precipitation route followed by calcination of the as-synthesized coprecipitates at 700-1000 °C under different gas atmospheres (air, N2 or argon). In situ synchrotron XRD at elevated temperatures reveals the conditions for synthesizing phase-pure materials. The stoichiometry of the samples is confirmed by inductively coupled plasma optical emission spectrometry as well as by structure refinement of neutron diffraction data of phase-pure specimens...
February 7, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Fatemeh Rezaei, Anton Nikiforov, Rino Morent, Nathalie De Geyter
Physical properties of pre-electrospinning polymer solutions play a key role in electrospinning as they strongly determine the morphology of the obtained electrospun nanofibers. In this work, an atmospheric-pressure argon plasma directly submerged in the liquid-phase was used to modify the physical properties of poly lactic acid (PLA) spinning solutions in an effort to improve their electrospinnability. The electrical characteristics of the plasma were investigated by two methods; V-I waveforms and Q-V Lissajous plots while the optical emission characteristics of the plasma were also determined using optical emission spectroscopy (OES)...
February 2, 2018: Scientific Reports
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