Sample records for argon plasma coagulation

  1. Coagulation of Dust Particles in Argon Plasma of RF Discharge

    SciTech Connect

    Mankelevich, Yu. A.; Olevanov, M. A.; Pal, A. F.; Rakhimova, T. V.; Ryabinkin, A. N.; Serov, A. O. [Lomonosov Moscow State University Skobeltsyn Institute of Nuclear Physics, 1(2), Leninskie gory, GSP-1, Moscow 119991 (Russian Federation); Filippov, A. V. [Troitsk Institute for Innovation and Fusion Research, Troitsk 142190, Moscow region (Russian Federation)

    2008-09-07

    The experiments on coagulation of poly-disperse particles with various size distributions injected into the argon plasma of the magnetron radio-frequency discharge are discussed. The experiments were carried out under the conditions similar to those using dusty plasma for technology applications. Within the created theory the threshold behavior of the coagulation process was explained for the first time, the estimation of the critical particle size for onset of a fast coagulation was made, and the analytical calculation of the coagulation rate of dust particles was performed. The proposed coagulation mechanism makes it possible to describe the typical features of coagulation processes observed in experiments and to explain the effects of attraction and coalescence of highly negatively charged microns size particles.

  2. Argon plasma coagulation therapy for hemorrhagic radiation proctosigmoiditis

    Microsoft Academic Search

    Rui A. Silva; António J. Correia; Luís Moreira Dias; Helena Lomba Viana; Rafael Lomba Viana

    1999-01-01

    Background: Radiation-induced proctosigmoiditis is a serious complication of pelvic radiation therapy. Rectal bleeding occurs among 6% to 8% of these patients and is extremely difficult to manage. Pharmacotherapy is generally ineffective, whereas surgical treatment is associated with high morbidity and mortality. Argon plasma coagulation is a new method of noncontact electrocoagulation well suited for hemostasis of large bleeding areas. Methods:

  3. Histology assessment of bipolar coagulation and argon plasma coagulation on digestive tract

    PubMed Central

    Garrido, Teresa; Baba, Elisa R; Wodak, Stephanie; Sakai, Paulo; Cecconello, Ivan; Maluf-Filho, Fauze

    2014-01-01

    AIM: To analyze the effect of bipolar electrocoagulation and argon plasma coagulation on fresh specimens of gastrointestinal tract. METHODS: An experimental evaluation was performed at Hospital das Clinicas of the University of São Paulo, on 31 fresh surgical specimens using argon plasma coagulation and bipolar electrocoagulation at different time intervals. The depth of tissue damage was histopathologically analyzed by single senior pathologist unaware of the coagulation method and power setting applied. To analyze the results, the mucosa was divided in superficial mucosa (epithelial layer of the esophagus and superficial portion of the glandular layer of the stomach and colon) intermediate mucosa (until the lamina propria of the esophagus and until the bottom of the glandular layer of the stomach and colon) and muscularis mucosa. Necrosis involvement of the layers was compared in several combinations of power and time interval. RESULTS: Involvement of the intermediate mucosa of the stomach and of the muscularis mucosa of the three organs was more frequent when higher amounts of energy were used with argon plasma. In the esophagus and in the colon, injury of the intermediate mucosa was frequent, even when small amounts of energy were used. The use of bipolar electrocoagulation resulted in more frequent involvement of the intermediate mucosa and of the muscularis mucosa of the esophagus and of the colon when higher amounts of energy were used. In the stomach, these involvements were rare. The risk of injury of the muscularis propria was significant only in the colon when argon plasma coagulation was employed. CONCLUSION: Tissue damage after argon plasma coagulation is deeper than bipolar electrocoagulation. Both of them depend on the amount of energy used. PMID:25031789

  4. Large sessile colonic adenomas: use of argon plasma coagulator to supplement piecemeal snare polypectomy

    Microsoft Academic Search

    Jusuf Zlatanic; Jerome D. Waye; Peter S. Kim; Peter J. Baiocco; Gilbert W. Gleim

    1999-01-01

    Background: Residual adenoma is frequently found at the site of endoscopically resected large sessile adenomas on follow-up examination. We evaluated the efficacy of a thermal energy source, the argon plasma coagulator, to destroy visible residual adenoma after piecemeal resection of sessile polyps. Methods: Seventy-seven piecemeal polypectomies with or without the use of argon plasma coagulator were analyzed retrospectively. All polyps

  5. Argon Plasma Coagulation for the Treatment of Hemorrhagic Radiation Colitis

    PubMed Central

    Lam, Mindy C.W.; Parliament, Matthew; Wong, Clarence K.W.

    2012-01-01

    Radiation colitis is a common consequence of pelvic radiation. Its complications may include anemia due to chronic bleeding requiring transfusions. Many of these patients are managed with rectal medications which are often inadequate for control. Argon plasma coagulation (APC) has been well described for its efficacy in treating radiation proctitis. Here we present two cases in whom APC therapy was used to treat severe radiation colitis. We reviewed two cases originally seen at the regional cancer center (Cross Cancer Institute) in Edmonton, Alberta, Canada. Both patients received pelvic radiation for recurrent endometrial cancers and were referred for active bleeding secondary to radiation colitis that had required numerous transfusions. Radiation-induced telangiectasias were found from 10–50 cm in the sigmoid colon. Both patients had significant improvement of symptoms after one session of APC treatment set at 40–60 W and gas flow of 2.0 l/min. There were no complications from the procedures. Neither patient required blood transfusions after the treatment with improvement in their hemoglobin levels and were doing well at 3- and 6-month follow-up. APC can be used effectively to provide immediate and sustained resolution of symptoms in patients with radiation colitis. PMID:22933988

  6. Rectal ulcer: Due to ketoprofen, argon plasma coagulation and prostatic brachytherapy

    PubMed Central

    Koessler, Thibaud; Servois, Vincent; Mariani, Pascale; Aubert, Emilie; Cacheux, Wulfran

    2014-01-01

    Prostatic brachytherapy with permanent seed implants is a recent and safe radiation therapy technique associated with radiation-induced digestive disease. Argon plasma coagulation procedure is a validated modality in the management of haemorrhagic radiation proctitis, which is known to occasionally induce chronic rectal ulcers. We report here an original case report of an acute painful rectal ulcer as a consequence of the combination of short-term therapy with non-steroidal anti-inflammatory drugs therapy, prostatic brachytherapy with malposition of seed implants and argon plasma coagulation procedure in a patient with haemorrhagic radiation proctitis. The description of this clinical observation is essential to recommend the discontinuation of non-steroidal anti-inflammatory drugs therapy and the control of the position of seed implants in case of prostatic brachytherapy before argon plasma coagulation for radiation-induced proctitis. PMID:25493041

  7. Restoration of the normal squamous lining in Barrett's esophagus by argon beam plasma coagulation

    Microsoft Academic Search

    James P. Byrne; Gordon R. Armstrong; Stephen E. A. Attwood

    1998-01-01

    Objective:Barrett's esophagus is associated with significantly increased risk of development of esophageal adenocarcinoma. Replacing columnar epithelium with the normal squamous lining in this condition offers the possibility of decreasing the risk of degeneration to invasive adenocarcinoma. This study aimed to establish the feasibility of argon beam plasma coagulation (ABPC), in conjunction with control of gastroesophageal reflux, to restore the squamous

  8. Prospective comparison of argon plasma coagulator and heater probe in the endoscopic treatment of major peptic ulcer bleeding

    Microsoft Academic Search

    Livio Cipolletta; Maria Antonia Bianco; Gianluca Rotondano; Roberto Piscopo; Antonio Prisco; Maria Lucia Garofano

    1998-01-01

    Background: Argon plasma coagulator was prospectively compared with heater probe in patients with bleeding peptic ulcers. Methods: Forty-one patients with major stigmata of ulcer hemorrhage were randomly assigned to receive either heater probe (n = 20) or argon plasm coagulation (n = 21) treatment; 40% had active bleeding and 60% had a nonbleeding visible vessel in the ulcer crater. The

  9. Argon plasma coagulation in the management of uncovered tracheal stent fracture

    PubMed Central

    Ching, Yiu-Hei; Geck, Robert D.; Andrews, Arthur D.; Rumbak, Mark J.; Camporesi, Enrico M.

    2014-01-01

    Endotracheal and endobronchial stenting, particularly with uncovered stents, can be complicated by stent fracture, granulation tissue formation, direct airway injury, and airway obstruction. While stent removal is possible, it can result in significant complications and long-term benefit is not guaranteed. Argon plasma coagulation can be employed to trim fractured stent fragments and remove granulation tissue simultaneously. In this manuscript, we report a case and describe our experience with using this technique.

  10. Topical estrogens combined with argon plasma coagulation in the management of epistaxis in hereditary hemorrhagic telangiectasia.

    PubMed

    Bergler, Wolfgang; Sadick, Haneen; Gotte, Karl; Riedel, Frank; Hörmann, Karl

    2002-03-01

    The aim of this study was to assess the value of topically applied estrogens in patients with hereditary hemorrhagic telangiectasia. Twenty-six patients with this disorder were treated with argon plasma coagulation and randomized into 2 groups: group A, which had postoperative application of estriol ointment (n = 14), and group B, which had postoperative application of dexpanthenol ointment (n = 12). Over a period of 12 months, the frequency and intensity of bleeding, the patient's satisfaction, and the success of the treatment were evaluated with a questionnaire. Before the operation, more than 90% of the patients in both groups complained of daily episodes of epistaxis. Twelve months after treatment, the frequency and intensity of bleeding had significantly decreased in group A as compared to group B. Of the patients in group A, 93% were satisfied with the treatment. Of the patients in group B, only 42% were satisfied with the treatment. In both groups, more than 90% of the patients were willing to undergo the same treatment again. The combined treatment approach with argon plasma coagulation and topical estriol enables us to significantly prolong the hemorrhage-free interval. PMID:11913682

  11. Treatment with argon plasma coagulation reduces recurrence after piecemeal resection of large sessile colonic polyps: A randomized trial and recommendations

    Microsoft Academic Search

    Jim C. Brooker; Brian P. Saunders; Syed G. Shah; Catherine J. Thapar; Noriko Suzuki; Christopher B. Williams

    2002-01-01

    Background: Recurrence is frequent after piecemeal snare resection of large sessile colorectal polyps. The aim of this study was to evaluate the safety and efficacy of argon plasma coagulation (APC) in preventing recurrence when applied to the edge and base of the polypectomy site after apparently complete piecemeal resection. Methods: Patients with large (>1.5 cm) sessile polyps removed by piecemeal

  12. Effective treatment of solitary rectal ulcer syndrome using argon plasma coagulation.

    PubMed

    Waniczek, Dariusz; Rdes, Jerzy; Rudzki, Marek K; Piecuch, Jerzy; Rubicz, Nina; Arendt, Jerzy

    2014-01-01

    Solitary rectal ulcer syndrome (SRUS) is a chronic, multiform, non-cancerous disorder of the rectum, the final diagnosis of which is based upon histopathological criteria. This disorder is often accompanied by latent proctoptosis. We present a patient who (in 1996) was the first case in which argon plasma coagulation (APC) was used for SRUS treatment. In the years 2004-2005 the same patient underwent 15 APC sessions (at monthly intervals) obtaining full recovery from SRUS, although she had been treated unsuccessfully for 17 years prior to that. Six-year observation did not show any relapse. Local therapy with APC seems to be an important alternative in SRUS treatment without prolapse of the rectum and could become a basic method for bleeding treatment in SRUS. PMID:25276257

  13. Effective treatment of solitary rectal ulcer syndrome using argon plasma coagulation

    PubMed Central

    Waniczek, Dariusz; Rdes, Jerzy; Piecuch, Jerzy; Rubicz, Nina; Arendt, Jerzy

    2014-01-01

    Solitary rectal ulcer syndrome (SRUS) is a chronic, multiform, non-cancerous disorder of the rectum, the final diagnosis of which is based upon histopathological criteria. This disorder is often accompanied by latent proctoptosis. We present a patient who (in 1996) was the first case in which argon plasma coagulation (APC) was used for SRUS treatment. In the years 2004–2005 the same patient underwent 15 APC sessions (at monthly intervals) obtaining full recovery from SRUS, although she had been treated unsuccessfully for 17 years prior to that. Six-year observation did not show any relapse. Local therapy with APC seems to be an important alternative in SRUS treatment without prolapse of the rectum and could become a basic method for bleeding treatment in SRUS. PMID:25276257

  14. Therapeutic effect of argon plasma coagulation on small malignant gastrointestinal tumors.

    PubMed

    Sessler, M J; Becker, H D; Flesch, I; Grund, K E

    1995-01-01

    In endoscopy, argon plasma coagulation (APC) is a new principle of non-contact electrocoagulation and has proved to be a sufficient tool for palliative endoscopic treatment of gastrointestinal neoplasms, predominantly of the oesophagus and colorectum. In a study of 67 patients suffering from histologically confirmed and endosonographic T1-staged tumours of the gastrointestinum, 10 patients were selected for endoscopic APC treatment because of the impossibility of surgical therapy. Although the application was primarily of a palliative nature, in 9 of 10 cases of minor neoplasms, no further tumour could be detected in biopsies during the observation period (9.45 +/- 2.8 months). One patient was not cured locally. In none of the patients was any serious complication noticed during the outpatient follow-up. The effective results and lack of severe complications suggest this technique as an alternative therapy in selected patients with smaller gastrointestinal tumours. PMID:7538505

  15. Eradication of Barrett’s mucosa with argon plasma coagulation and acid suppression: immediate and mid term results

    Microsoft Academic Search

    J-L Van Laethem; M Cremer; M O Peny; M Delhaye; J Devière

    1998-01-01

    Background—Intestinal metaplastic mucosa in Barrett’s oesophagus can be replaced by squamous epithelium after mucosal thermal ablation associated with acid suppression therapy.Aims—To assess whether restoration of squamous epithelium can be obtained after ablation of Barrett’s oesophagus using argon plasma coagulation (APC) associated with proton pump inhibitor (PPI) therapy.Methods—Thirty one patients with Barrett’s oesophagus received APC. Omeprazole (40 mg\\/day) was given from

  16. Clinical Outcomes of Argon Plasma Coagulation Therapy for Early Gastric Neoplasms

    PubMed Central

    Kim, Kyu Young; Yang, Hea Min; Lee, Yu Rim; Kang, Eun Jeong; Lee, Hyun Seok; Kim, Sung Kook

    2015-01-01

    Background/Aims Argon plasma coagulation (APC) has some merits in the treatment of gastric neoplasms including a shorter operative time and fewer complications compared with endoscopic mucosal resection or endoscopic submucosal dissection. However, there are few reports on the outcomes of gastric neoplasms treated using APC. The aim of this study was to evaluate APC in the treatment of early gastric neoplasms in terms of clinical efficacy, safety, and local recurrence. Methods We enrolled 28 patients who received APC therapy at the Kyungpook National University Hospital between May 2007 and April 2013. Clinical outcomes were analyzed. Results The median follow-up period was 24.8 months (range, 2 to 78). Among the 28 lesions treated using the APC procedure, tumor recurrence was encountered in seven lesions (25.0%). Recurrence was found in 50% (5/10) of single APC cases and 11% (2/18) of rescue APC cases. The mean time to recurrence was 16.1 months (range, 2 to 78). There were no serious APC-related complications such as perforation, bleeding, or infection. Conclusions APC therapy can be a useful treatment with a favorable safety profile for patients with early gastric neoplasms. However, further studies are necessary to determine the long-term prognosis of patients undergoing this treatment.

  17. Successful Treatment of Severe Spontaneous Periampullary Bleeding with Argon Plasma Coagulation

    PubMed Central

    Abadir, Amir

    2014-01-01

    Periampullary bleeding is an uncommon cause of upper gastrointestinal (GI) hemorrhage, which is typically iatrogenic in origin occurring as the result of endoscopic intervention of the papilla. Spontaneous, non-iatrogenic periampullary bleeding is extraordinarily rare with only a few cases reported in the literature to date. Vascular malformations, including angiodysplasia and Dieulafoy’s lesions, have been implicated in several reports as the etiology but endoscopic intervention is often unsuccessful in achieving durable hemostasis with surgery being required for definitive management in many cases. Herein is reported the case of a 67-year-old male on anticoagulation for atrial fibrillation who presented with severe upper GI bleeding determined to be arising from underneath the hood of the major papilla. No distinct lesion was seen endoscopically but the presumed etiology was an unidentified vascular malformation. Successful treatment was achieved with argon plasma coagulation (APC) applied circumferentially around the papilla. No subsequent endoscopic or surgical intervention was required for durable hemostasis and the patient was able to resume anticoagulation shortly after the procedure. This is the first reported case of spontaneous periampullary bleeding successfully treated with APC. PMID:25237214

  18. Video: argon plasma coagulator in a 2-month-old child with tracheoesophageal fistula.

    PubMed

    Nardo, Giovanni Di; Oliva, Salvatore; Barbato, Maria; Aloi, Marina; Midulla, Fabio; Roggini, Mario; Valitutti, Francesco; Frediani, Simone; Cucchiara, Salvatore

    2012-09-01

    A 2 month-old boy was admitted to the authors' hospital because of regurgitation and persistent cough during breastfeeding. A chest X-ray examination and a barium esophagogram disclosed small amounts of barium passing in the trachea, suggesting a tracheoesophageal fistula (TEF). Bronchoscopy combined with upper gastrointestinal (GI) endoscopy performed with the patient under general anesthesia confirmed the fistula. The TEF was treated by injection of 1 ml Glubran 2 from the esophageal side. A nasogastric tube was placed for feedings, and 7 days later, a barium esophagogram showed a reduction of caliber but not complete closure of the TEF. Unsuccessful fistula obliteration with Glubran was attributed to technical difficulties in catheterization of the fistula orifice, mainly resulting from its close proximity to the upper esophageal sphincter and to its small caliber. Therefore, an argon plasma coagulator (APC) probe with a circumferentially oriented nozzle was used from the esophageal side as an alternative technique to fulgurate the residual fistula orifice (see video). A nasogastric tube was placed for feedings. Oral feeding was started 7 days later when a barium esophagogram confirmed complete fistula closure. At the 2-year follow-up visit, the boy was asymptomatic, and the barium esophagogram was negative. This report describes a case in which esophagoscopy gave a clear view of the fistula due to its direction from esophagus to trachea. Complete fistula obliteration was not obtained with Glubran. However, APC was successfully used to close the residual fistula orifice. The authors suggest that APC can be used as an alternative endoscopic technique to repair TEF when other techniques fail. PMID:22476825

  19. Argon Plasma Coagulation Therapy Versus Topical Formalin for Intractable Rectal Bleeding and Anorectal Dysfunction After Radiation Therapy for Prostate Carcinoma

    SciTech Connect

    Yeoh, Eric, E-mail: eric.yeoh@health.sa.gov.au [Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide (Australia); School of Medicine, University of Adelaide, Adelaide (Australia); Tam, William; Schoeman, Mark [School of Medicine, University of Adelaide, Adelaide (Australia); Department of Gastroenterology, Royal Adelaide Hospital, Adelaide (Australia); Moore, James; Thomas, Michelle [School of Medicine, University of Adelaide, Adelaide (Australia); Department of Colorectal Surgery, Royal Adelaide Hospital, Adelaide (Australia); Botten, Rochelle; Di Matteo, Addolorata [Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide (Australia)

    2013-12-01

    Purpose: To evaluate and compare the effect of argon plasma coagulation (APC) and topical formalin for intractable rectal bleeding and anorectal dysfunction associated with chronic radiation proctitis. Methods and Materials: Thirty men (median age, 72 years; range, 49-87 years) with intractable rectal bleeding (defined as ?1× per week and/or requiring blood transfusions) after radiation therapy for prostate carcinoma were randomized to treatment with APC (n=17) or topical formalin (n=13). Each patient underwent evaluations of (1) anorectal symptoms (validated questionnaires, including modified Late Effects in Normal Tissues–Subjective, Objective, Management, and Analytic and visual analogue scales for rectal bleeding); (2) anorectal motor and sensory function (manometry and graded rectal balloon distension); and (3) anal sphincteric morphology (endoanal ultrasound) before and after the treatment endpoint (defined as reduction in rectal bleeding to 1× per month or better, reduction in visual analogue scales to ?25 mm, and no longer needing blood transfusions). Results: The treatment endpoint was achieved in 94% of the APC group and 100% of the topical formalin group after a median (range) of 2 (1-5) sessions of either treatment. After a follow-up duration of 111 (29-170) months, only 1 patient in each group needed further treatment. Reductions in rectal compliance and volumes of sensory perception occurred after APC, but no effect on anorectal symptoms other than rectal bleeding was observed. There were no differences between APC and topical formalin for anorectal symptoms and function, nor for anal sphincteric morphology. Conclusions: Argon plasma coagulation and topical formalin had comparable efficacy in the durable control of rectal bleeding associated with chronic radiation proctitis but had no beneficial effect on anorectal dysfunction.

  20. Sixteen-year follow-up of Barrett’s esophagus, endoscopically treated with argon plasma coagulation

    PubMed Central

    Milashka, Mariana; Calomme, Annabelle; Van Laethem, Jean Luc; Blero, Daniel; Eisendrath, Pierre; Le Moine, Olivier

    2014-01-01

    Objective The thermal destruction of non-dysplastic Barrett’s esophagus (BE) and its replacement by squamous epithelium is an attractive, but unproven strategy to avoid further development of dysplasia or cancer. The goal of this study was to estimate the persistence of restoration of squamous epithelium and the risk of cancer in BE that was eradicated using argon plasma coagulation (APC) in the absence of high-grade dysplasia, 16 years after its application. Design We followed 32 patients with BE who underwent eradication of metaplastic epithelium using APC, up to 16 years later. Results At the end of the initial treatment, 25 of 32 patients (78%) had complete endoscopic eradication, there was partial squamous re-epithelialization in four patients (13%) and it was absent in three patients (9%). We observed buried metaplastic glands under new squamous epithelium in 6 of the 25 patients who had complete endoscopic eradication. At follow-up, sustained complete endoscopic eradication was observed in 16 of 32 patients (50%), partial eradication in 11 of 32 patients (35%); there were two patients (6%) lost to follow-up and three patients (9%) developed esophageal adenocarcinoma. Two of the latest cases arose from the buried glands under neosquamous epithelium after complete eradication and one arose from a small remaining Barrett’s segment. Conclusions We observed long-term re-epithelialization in the majority of patients who had previously had complete eradication of Barrett’s esophagus. This did not provide protection against cancer development, as the incidence of cancers arising from buried glands or from residual Barrett’s esophagus was similar to that observed in patients undergoing no specific treatment. PMID:25360314

  1. The tissue effect of argon-plasma coagulation with prior submucosal injection (Hybrid-APC) versus standard APC: A randomized ex-vivo study

    PubMed Central

    Neugebauer, Alexander; Scharpf, Marcus; Braun, Kirsten; May, Andrea; Ell, Christian; Fend, Falko; Enderle, Markus D

    2014-01-01

    Background Thermal ablation for Barrett’s oesophagus has widely been established in gastrointestinal endoscopy during the last decade. The mainly used methods of radiofrequency ablation (RFA) and argon-plasma coagulation (APC) carry a relevant risk of stricture formation of up to 5–15%. Newer ablation techniques that are able to overcome this disadvantage would therefore be desirable. The aim of the present study was to compare the depth of tissue injury of the new method of Hybrid-APC versus standard APC within a randomized study in a porcine oesophagus model. Methods Using a total of eight explanted pig oesophagi, 48 oesophageal areas were ablated either by standard or Hybrid-APC (APC with prior submucosal fluid injection) using power settings of 50 and 70?W. The depth of tissue injury to the oesophageal wall was analysed macroscopically and histopathologically. Results Using 50?W, mean coagulation depth was 937?±?469?µm during standard APC, and 477?±?271?µm during Hybrid-APC (p?=?0.064). Using 70?W, coagulation depth was 1096?±?320?µm (standard APC) and 468?±?136?µm (Hybrid-APC; p?=?0.003). During all settings, damage to the muscularis mucosae was observed. Using standard APC, damage to the submucosal layer was observed in 4/6 (50?W) and 6/6 cases (70?W). During Hybrid-APC, coagulation of the submucosal layer occurred in 2/6 (50?W) and 1/6 cases (70?W). The proper muscle layer was only damaged during conventional APC (50?W: 1/6; 70?W: 3/6). Limitations Ex-vivo animal study with limited number of cases. Conclusions Hybrid-APC reduces coagulation depth by half in comparison with standard APC, with no thermal injury to the proper muscle layer. It may therefore lead to a lower rate of stricture formation during clinical application. PMID:25360316

  2. Comparison of Hemostatic Efficacy of Argon Plasma Coagulation with and without Distilled Water Injection in Treating High-Risk Bleeding Ulcers

    PubMed Central

    Hsu, Ping-I; Chan, Hoi-Hung; Wang, Kai-Ming; Tsai, Wei-Lun; Yu, Hsien-Chung; Tsay, Feng-Woei

    2014-01-01

    Background. Argon plasma coagulation (APC) is useful to treat upper gastrointestinal bleeding, but its hemostatic efficacy has received little attention. Aims. This investigation attempted to determine whether additional endoscopic injection before APC could improve hemostatic efficacy in treating high-risk bleeding ulcers. Methods. From January 2007 to April 2011, adult patients with high-risk bleeding ulcers were included. This investigation compared APC plus distilled water injection (combined group) to APC alone for treating high-risk bleeding ulcers. Outcomes were assessed based on initial hemostasis, surgery, blood transfusion, hospital stay, rebleeding, and mortality at 30 days posttreatment. Results. Totally 120 selected patients were analyzed. Initial hemostasis was accomplished in 59 patients treated with combined therapy and 57 patients treated with APC alone. No significant differences were noted between these groups in recurred bleeding, emergency surgery, 30-day mortality, hospital stay, or transfusion requirements. Comparing the combined end point of mortality plus the failure of initial hemostasis, rebleeding, and the need for surgery revealed an advantage for the combined group (P = 0.040). Conclusions. Endoscopic therapy with APC plus distilled water injection was no more effective than APC alone in treating high-risk bleeding ulcers, whereas combined therapy was potentially superior for patients with poor overall outcomes. PMID:25243138

  3. Hemostasis after partial hepatectomy using argon beam coagulation and a concentrated albumin

    Microsoft Academic Search

    Hua Xie; Ronald F. Wolf; John Petty; Allen Burke; Jeffery S. Teach; Kenton W. Gregory; Scott A. Prahl

    Background: The argon beam coagulator (ABC) is frequently used to control bleeding on parenchymatous organs during surgery. The purpose of this study was to assess whether it improves the efficacy of hemostasis of using the argon beam coagulation with a concentrated human albumin at partial hepatectomy. Methods: Thirty-two domestic swine were randomized and treated with either conventional argon beam coagulation

  4. Coagulation Factor XIIIa Substrates in Human Plasma

    PubMed Central

    Nikolajsen, Camilla Lund; Dyrlund, Thomas F.; Poulsen, Ebbe Toftgaard; Enghild, Jan J.; Scavenius, Carsten

    2014-01-01

    Coagulation factor XIII (FXIII) is a transglutaminase with a well defined role in the final stages of blood coagulation. Active FXIII (FXIIIa) catalyzes the formation of ?-(?-glutamyl)lysine isopeptide bonds between specific Gln and Lys residues. The primary physiological outcome of this catalytic activity is stabilization of the fibrin clot during coagulation. The stabilization is achieved through the introduction of cross-links between fibrin monomers and through cross-linking of proteins with anti-fibrinolytic activity to fibrin. FXIIIa additionally cross-links several proteins with other functionalities to the clot. Cross-linking of proteins to the clot is generally believed to modify clot characteristics such as proteolytic susceptibility and hereby affect the outcome of tissue damage. In the present study, we use a proteomic approach in combination with transglutaminase-specific labeling to identify FXIIIa plasma protein substrates and their reactive residues. The results revealed a total of 147 FXIIIa substrates, of which 132 have not previously been described. We confirm that 48 of the FXIIIa substrates were indeed incorporated into the insoluble fibrin clot during the coagulation of plasma. The identified substrates are involved in, among other activities, complement activation, coagulation, inflammatory and immune responses, and extracellular matrix organization. PMID:24443567

  5. Coagulation of dust particles in plasma

    NASA Astrophysics Data System (ADS)

    Matthews, Lorin; Carmona-Reyes, Jorge; Land, Victor; Ma, Qianyu; Deline, Kristen; Perry, Jonathan; Doyle, Brandon; Hyde, Truell

    2011-10-01

    Dusty plasmas are found in numerous astrophysical environments. Coagulation of the charged dust changes their interaction with the plasma and affects the subsequent dynamics and evolution of the system. The complex microphysics underlying these processes depends on parameters specific to the ambient environment and the grains themselves. Different charging processes can yield populations of grains which are all charged negatively or charged with opposite polarities. The charge on an aggregate distributes itself over the aggregate's surface which can be approximated theoretically by assuming a multipole distribution. The dipole-dipole charge interactions between aggregates lead to rotations of the colliding grains. Other grain properties also influence the coagulation process, such as the monomer shape or the presence of magnetic material. The morphology of the resultant aggregates affects subsequent coagulation. Porous fluffy aggregates are more strongly coupled to the gas, leading to reduced collisional velocities, and greater collisional cross sections. An overview of the numerical and experimental methods used to study dust coagulation at CASPER will be given.

  6. Axisymmetric Argon-Plasma-Jet Behaviors in Argon Surrounding Based on a Lattice Boltzmann Computational Method

    E-print Network

    Axisymmetric Argon-Plasma-Jet Behaviors in Argon Surrounding Based on a Lattice Boltzmann, in one side, as former studies, E. Pfender et al. [2] have performed a simulation of Argon plasma, and surrounding atmosphere). In a comparative study, D.-Y. Xu et al. [8] have shown that using argon instead

  7. Total laparoscopic radical hysterectomy with pelvic lymphadenectomy using the argon-beam coagulator: pilot data and comparison to laparotomy

    Microsoft Academic Search

    Nadeem R Abu-Rustum; Mary L Gemignani; Kathleen Moore; Yukio Sonoda; Ennapadam Venkatraman; Carol Brown; Elizabeth Poynor; Dennis S Chi; Richard R Barakat

    2003-01-01

    ObjectivesThe aim of this study was to describe the feasibility and outcome of total laparoscopic radical hysterectomy with pelvic lymphadenectomy for stage I cervical cancer using the argon-beam coagulator.

  8. Contact activation of blood-plasma coagulation

    NASA Astrophysics Data System (ADS)

    Golas, Avantika

    Surface engineering of biomaterials with improved hemocompatibility is an imperative, given the widespread global need for cardiovascular devices. Research summarized in this dissertation focuses on contact activation of FXII in buffer and blood plasma frequently referred to as autoactivation. The extant theory of contact activation imparts FXII autoactivation ability to negatively charged, hydrophilic surfaces. According to this theory, contact activation of plasma involves assembly of proteins comprising an "activation complex" on activating surfaces mediated by specific chemical interactions between complex proteins and the surface. This work has made key discoveries that significantly improve our core understanding of contact activation and unravel the existing paradigm of plasma coagulation. It is shown herein that contact activation of blood factor XII (FXII, Hageman factor) in neat-buffer solution exhibits a parabolic profile when scaled as a function of silanized-glass-particle activator surface energy (measured as advancing water adhesion tension t°a=g° Iv costheta in dyne/cm, where g°Iv is water interfacial tension in dyne/cm and theta is the advancing contact angle). Nearly equal activation is observed at the extremes of activator water-wetting properties --36 < t°a < 72 dyne/cm (O° ? theta < 120°), falling sharply through a broad minimum within the 20 < t°a < 40 dyne/cm (55° < theta < 75°). Furthermore, contact activation of FXII in buffer solution produces an ensemble of protein fragments exhibiting either procoagulant properties in plasma (proteolysis of blood factor XI or prekallikrein), amidolytic properties (cleavage of s-2302 chromogen), or the ability to suppress autoactivation through currently unknown biochemistry. The relative proportions of these fragments depend on activator surface chemistry/energy. We have also discovered that contact activation is moderated by adsorption of plasma proteins unrelated to coagulation through an "adsorption-dilution" effect that blocks FXII contact with hydrophobic activator surfaces. The adsorption-dilution effect explains the apparent specificity for hydrophilic activators pursued by earlier investigators. Finally a comparison of FXII autoactivation in buffer, serum, protein cocktail, and plasma solutions is shown herein. Activation of blood plasma coagulation in vitro by contact with material surfaces is demonstrably dependent on plasma-volume-to-activator-surface-area ratio. However, activation of factor XII dissolved in buffer, protein cocktail, heat-denatured serum, and FXI deficient plasma does not exhibit activator surface-area dependence. Instead, a highly-variable burst of procoagulant-enzyme yield is measured that exhibits no measurable kinetics, sensitivity to mixing, or solution-temperature dependence. Thus, FXII activation in both buffer and protein-containing solutions does not exhibit characteristics of a biochemical reaction but rather appears to be a "mechanochemical" reaction induced by FXII molecule interactions with hydrophilic activator particles that do not formally adsorb blood proteins from solution. Results strongly suggest that activator surface-area dependence observed in contact activation of plasma coagulation does not solely arise at the FXII activation step of the intrinsic pathway.

  9. Diamond film growth argon-carbon plasmas

    DOEpatents

    Gruen, Dieter M. (Downers Grove, IL); Krauss, Alan R. (Naperville, IL); Liu, Shengzhong (Canton, MI); Pan, Xianzheng (Wuhan Hubei, CN); Zuiker, Christopher D. (LaGrange, IL)

    1998-01-01

    A method and system for manufacturing diamond film. The method involves forming a carbonaceous vapor, providing a gas stream of argon, hydrogen and hydrocarbon and combining the gas with the carbonaceous vapor, passing the combined carbonaceous vapor and gas carrier stream into a chamber, forming a plasma in the chamber causing fragmentation of the carbonaceous and deposition of a diamond film on a substrate.

  10. Merging of high speed argon plasma jets

    SciTech Connect

    Case, A.; Messer, S.; Brockington, S.; Wu, L.; Witherspoon, F. D. [HyperV Technologies Corp., Chantilly, Virginia 22180 (United States); Elton, R. [University of Maryland, College Park, Maryland 20742 (United States)

    2013-01-15

    Formation of an imploding plasma liner for the plasma liner experiment (PLX) requires individual plasma jets to merge into a quasi-spherical shell of plasma converging on the origin. Understanding dynamics of the merging process requires knowledge of the plasma phenomena involved. We present results from the study of the merging of three plasma jets in three dimensional geometry. The experiments were performed using HyperV Technologies Corp. 1 cm Minirailguns with a preionized argon plasma armature. The vacuum chamber partially reproduces the port geometry of the PLX chamber. Diagnostics include fast imaging, spectroscopy, interferometry, fast pressure probes, B-dot probes, and high speed spatially resolved photodiodes, permitting measurements of plasma density, temperature, velocity, stagnation pressure, magnetic field, and density gradients. These experimental results are compared with simulation results from the LSP 3D hybrid PIC code.

  11. [Experimental study of the effect of the Argon Beam Coagulator on organic tissues from the viewpoint of surgical utilization].

    PubMed

    Falbo, B; Vene, M; Visini, R; Grottola, T; Di Paolo, S; Picardi, N

    2004-01-01

    The Argon Beam Coagulator has gained his space in surgery thanks to its operative characteristics, that are very useful in sealing the bleeding parenchymal tissue with minimal injury to the surroundings. The aim of the present study is that of evaluate the physical properties of the instrument in its coagulation action. The experimental study with the Birtcher 6000 Argon Beam Coagulator has been designed to measure the top temperature that develops right where the Argon beam meets the tissue, while operating. Using a laser guided telethermometer, the searching of that temperature was uneasy right on the operatory field because of the unwilling movements of the operator hand and those of the patient himself. Therefore a similar protocol was made on a piece of meat coming from the butcher. At the longest application of the beam coagulation on the same point the developed temperature was never higher than 100 degrees C whilst a complete coagulation effects. The advantage of the Argon Beam coagulation are therefore to seal the diffuse bleeding without injury to this adjacent tissues, never exposed to a temperature higher than that of boiling water. The advantages are also evident in comparison with the more usual spray electrosurgery that is instead characterized by a wide carbonisation also with this spray option. PMID:15283389

  12. Diamond film growth argon-carbon plasmas

    DOEpatents

    Gruen, D.M.; Krauss, A.R.; Liu, S.Z.; Pan, X.Z.; Zuiker, C.D.

    1998-12-15

    A method and system are disclosed for manufacturing diamond film. The method involves forming a carbonaceous vapor, providing a gas stream of argon, hydrogen and hydrocarbon and combining the gas with the carbonaceous vapor, passing the combined carbonaceous vapor and gas carrier stream into a chamber, forming a plasma in the chamber causing fragmentation of the carbonaceous and deposition of a diamond film on a substrate. 29 figs.

  13. Role of electronic excitation on thermodynamic and transport properties of argon and argon-hydrogen plasmas

    SciTech Connect

    Singh, Kuldip; Singh, Gurpreet; Sharma, Rohit [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India)

    2010-07-15

    Thermodynamic and electron transport properties of the argon and argon-hydrogen plasmas have been calculated under the local thermodynamic equilibrium conditions in temperature range of 10 000-40 000 K over the wide range of pressures. Electronic excitation affects strongly these properties especially at high pressures. The inclusion of electronically excited states (EES) in relevant partition function influences the internal contribution to frozen and total specific heat for argon and argon-hydrogen plasma and it has been observed that although the total specific heat of argon plasma is less than that of hydrogen plasma, yet its internal contribution is more. Compensation between different contributions to total specific heat (by including and neglecting EES) occurring in hydrogen plasmas at low pressures has not been observed in argon and argon-hydrogen plasmas. As electron transport properties strongly depend upon the degree of ionization, therefore larger relative errors are found for these properties with and without EES, and in contrast to hydrogen plasma there exist a dominance of electron-atom cross section at low temperatures and EES dominance at intermediate temperatures.

  14. ECR Plasma Sterilisation, Argon and Nitrogen Treated Plasma

    NASA Astrophysics Data System (ADS)

    Helhel, Selcuk; Oksuz, Lutfi; Cerezci, Osman; Rad, Abbas Y.

    2004-09-01

    ECR type plasma system was built to produce plasma in axial direction. Plasma was initiated in a specially designed Nickel - Chrome cylindrical vacuum tube which is being driven through dielectric window by 2.45GHz commercial magnetron source. Tube is also surrounded by a coil driving 150ADC to generate approximately 875Gauss magnetic field at the center. Langmuir probe and ICCD for optical spectrometry were used to characterize internal parameters like electron density, electron temperature and different characteristics of the plasma. Bacillus Subtilis var nigar, bacillus Stearothermophilus, bacillus pumilus E601, Escherichia coli and staphylococcus aureus type bacteria were selected as a reference. Each is resistant for different actions while the Bacilus cereus is the most resistant bacteria for microwave interaction. This study presents the effect of system on used bacteria. Those are gram positive and gram negative bacteria that refers to structure of cell wall. The sterilization efficacy of Argon type ECR plasma was found to be over 99, 5% in Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis (vegetative cell), Bacillus cereus (vegetative cell), Bacillus pumilus and Escherichia coli. System response type is less than 2 minutes.

  15. COAGULATION

    EPA Science Inventory

    This chapter reports on the efforts of the USEPA to study conventional and enhanced coagulation for the control of disinfection by-products (DBPs) in drinking water. It examines the control of DBPs like trihalomethanes, haloacetic acids and the surrogate total organic halide in t...

  16. Modeling of an argon cascaded arc plasma by ANSYS FLUENT

    NASA Astrophysics Data System (ADS)

    Wei, Guodong; Qi, Xin; Yang, Lei

    2014-04-01

    In this work, an argon cascaded arc plasma is simulated by the business software ANSYS FLUENT. In fact, thus plasma is a high temperature arc (plasma window) with an average temperature of 12000 °C, which can be used as a medium between high pressure and vacuum mainly due to its characteristics of high temperature. According to the simulating results, the temperature can reach as high as 11500 °C which is in great agreement with that of other reports about plasma window.

  17. Treatment of pitch in argon/hydrogen plasmas

    SciTech Connect

    Dlugogorski, B.Z.; Berk, D.; Munz, R.J. (Dept. of Chemical Engineering, McGill Univ., Montreal, Quebec H3A 2A7 (CA))

    1992-03-01

    This paper reports on pitch-like vacuum-distilled residue from the CANMET coprocessing process that was treated in a stationary particle reactor with argon/hydrogen plasmas. The production of light, unsaturated hydrocarbons was optimized as a function of the average plasma temperature, composition, and residence time. The unconverted residue was characterized in terms of its elemental and mineralogical content. In pure argon plasma, the conversion to acetylene was about 14% and did not vary appreciably with temperature; other hydrocarbons were detected only in trace quantities. In argon/hydrogen plasmas the maximum conversion to acetylene and ethylene (25%) was attained between 2900 and 3400 K. Large quantities of soot were produced, but no liquid hydrocarbons were detected. Sulfur was fixed in the unconverted residue by the reduction of calcium sulfate to calcium sulfide.

  18. Properties of radio-frequency heated argon confined uranium plasmas

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Pure uranium hexafluoride (UF6) was injected into an argon confined, steady state, rf-heated plasma within a fused silica peripheral wall test chamber. Exploratory tests conducted using an 80 kW rf facility and different test chamber flow configurations permitted selection of the configuration demonstrating the best confinement characteristics and minimum uranium compound wall coating. The overall test results demonstrated applicable flow schemes and associated diagnostic techniques were developed for the fluid mechanical confinement and characterization of uranium within an rf plasma discharge when pure UF6 is injected for long test times into an argon-confined, high-temperature, high-pressure, rf-heated plasma.

  19. Effect of argon addition on plasma parameters and dust charging in hydrogen plasma

    SciTech Connect

    Kakati, B., E-mail: bharatkakati15@gmail.com; Kausik, S. S.; Saikia, B. K. [Centre of Plasma Physics-Institute for Plasma Research, Nazirakhat, Sonapur, Kamrup 782402, Assam (India); Bandyopadhyay, M.; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India)

    2014-10-28

    Experimental results on effect of adding argon gas to hydrogen plasma in a multi-cusp dusty plasma device are reported. Addition of argon modifies plasma density, electron temperature, degree of hydrogen dissociation, dust current as well as dust charge. From the dust charging profile, it is observed that the dust current and dust charge decrease significantly up to 40% addition of argon flow rate in hydrogen plasma. But beyond 40% of argon flow rate, the changes in dust current and dust charge are insignificant. Results show that the addition of argon to hydrogen plasma in a dusty plasma device can be used as a tool to control the dust charging in a low pressure dusty plasma.

  20. Behavior of Excited Argon Atoms in Inductively Driven Plasmas

    SciTech Connect

    HEBNER,GREGORY A.; MILLER,PAUL A.

    1999-12-07

    Laser induced fluorescence has been used to measure the spatial distribution of the two lowest energy argon excited states, 1s{sub 5} and 1s{sub 4}, in inductively driven plasmas containing argon, chlorine and boron trichloride. The behavior of the two energy levels with plasma conditions was significantly different, probably because the 1s{sub 5} level is metastable and the 1s{sub 4} level is radiatively coupled to the ground state but is radiation trapped. The argon data is compared with a global model to identify the relative importance of processes such as electron collisional mixing and radiation trapping. The trends in the data suggest that both processes play a major role in determining the excited state density. At lower rfpower and pressure, excited state spatial distributions in pure argon were peaked in the center of the discharge, with an approximately Gaussian profile. However, for the highest rfpowers and pressures investigated, the spatial distributions tended to flatten in the center of the discharge while the density at the edge of the discharge was unaffected. The spatially resolved excited state density measurements were combined with previous line integrated measurements in the same discharge geometry to derive spatially resolved, absolute densities of the 1s{sub 5} and 1s{sub 4} argon excited states and gas temperature spatial distributions. Fluorescence lifetime was a strong fi.mction of the rf power, pressure, argon fraction and spatial location. Increasing the power or pressure resulted in a factor of two decrease in the fluorescence lifetime while adding Cl{sub 2} or BCl{sub 3} increased the fluorescence lifetime. Excited state quenching rates are derived from the data. When Cl{sub 2} or BCl{sub 3} was added to the plasma, the maximum argon metastable density depended on the gas and ratio. When chlorine was added to the argon plasma, the spatial density profiles were independent of chlorine fraction. While it is energetically possible for argon excited states to dissociate some of the molecular species present in this discharge, it does not appear to be a significant source of dissociation. The major source of interaction between the argon and the molecular species BCl{sub 3} and Cl{sub 2} appears to be through modification of the electron density.

  1. Radiative energy loss in a non-equilibrium argon plasma

    Microsoft Academic Search

    D. A. Benoy; Mullen van der JJAM; D. C. Schram

    1993-01-01

    The total radiative loss in atmospheric argon plasmas is calculated allowing for deviations from local Saha equilibrium LSE. The authors have taken into account non-equilibrium excited state populations using numerical and analytical collisional-radiative models. Simple expressions for the different radiation loss mechanisms are given in terms of the electron density, electron temperature and ionization degree. These quantities together with the

  2. Supersonic Argon Flow In An Arc Plasma Source

    SciTech Connect

    Izrar, B.; Dudeck, M. [Laboratoire d'Aerothermique, 1C avenue de la Recherche Scientifique, 45071 Orleans cedex (France); Andre, P. [Laboratoire des Arc Electriques et des Plasmas Thermiques, LAEPT, Universite Blaise Pascal, 24 av. des landais, 63177 Aubiere cedex (France); Elchinger, M. F.; Aubreton, J. [Institut des Procedes Appliques aux Materiaux, Faculte des sciences de Limoges, 123 avenue Albert Thomas, 87060 Limoges cedex (France)

    2006-01-15

    The plasma properties inside a D.C. arc-jet operating with argon is analysed by means of a continuum description taking into account non equilibrium ionization processes and dissipative effects. The relaxation of the different physical processes inside the nozzle and the evolution of the Mach number are aanalysed.

  3. Effect of helium on spatial plasma parameters in low pressure argon-helium plasma

    SciTech Connect

    Bang, Jin-Young; Han, Duksun; Cho, Sung-Won; Chung, Chin-Wook [Department of Electrical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)

    2012-04-16

    Spatial distributions of the electron energy probability function were measured using a Langmuir probe in side-type argon-helium inductively coupled plasma. Collisional dominated electron heating and a concave shape of plasma density profile were observed at 10 mTorr pure argon. As the helium proportion increased, the electron heating and density profile changed to collisionless dominated heating and a convex shape respectively, and the same tendency was shown when the pressure decreased in the pure argon plasma. These changes were due to the decrease in the e-n collision frequency and the expansion of the electron power dissipation region.

  4. Equation of state of partially ionized argon plasma

    SciTech Connect

    Chen, Q. F.; Zheng, J.; Gu, Y. J.; Chen, Y. L.; Cai, L. C.

    2011-11-15

    The ionization degree, Hugoniots, and equation of state of partially ionized argon plasma were calculated by using self-consistent fluid variational theory for temperature of 6-50 kK and density of 0.05-4.0 g/cm{sup 3}. The corrections of lowering of ionization energy of fluid argon caused by the interactions among all particles of Ar, Ar{sup +}, Ar{sup 2+}, and e have been taken into consideration in terms of the correlation contributions to the chemical potential which is determined self-consistently by the free energy function. The initial density effects of gas argon under shock compression have been discussed. Comparison is performed with available shock-wave experiments and other theoretical calculations.

  5. Flush-mounted probe diagnostics for argon glow discharge plasma.

    PubMed

    Xu, Liang; Cao, Jinxiang; Liu, Yu; Wang, Jian; Du, Yinchang; Zheng, Zhe; Zhang, Xiao; Wang, Pi; Zhang, Jin; Li, Xiao; Qin, Yongqiang; Zhao, Liang

    2014-09-01

    A comparison is made between plasma parameters measured by a flush-mounted probe (FP) and a cylindrical probe (CP) in argon glow discharge plasma. Parameters compared include the space potential, the plasma density, and the effective electron temperature. It is found that the ion density determined by the FP agrees well with the electron density determined by the CP in the quasi-neutral plasma to better than 10%. Moreover, the space potential and effective electron temperature calculated from electron energy distribution function measured by the FP is consistent with that measured by the CP over the operated discharge current and pressure ranges. These results present the FP can be used as a reliable diagnostic tool in the stable laboratory plasma and also be anticipated to be applied in other complicated plasmas, such as tokamaks, the region of boundary-layer, and so on. PMID:25273724

  6. Flush-mounted probe diagnostics for argon glow discharge plasma

    SciTech Connect

    Xu, Liang, E-mail: xld02345@mail.ustc.edu.cn; Cao, Jinxiang; Liu, Yu; Wang, Jian; Du, Yinchang; Zheng, Zhe; Zhang, Xiao; Wang, Pi [Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Jin; Li, Xiao; Qin, Yongqiang; Zhao, Liang [Science and Technology on Space Physics Laboratory, Beijing 100076 (China)

    2014-09-15

    A comparison is made between plasma parameters measured by a flush-mounted probe (FP) and a cylindrical probe (CP) in argon glow discharge plasma. Parameters compared include the space potential, the plasma density, and the effective electron temperature. It is found that the ion density determined by the FP agrees well with the electron density determined by the CP in the quasi-neutral plasma to better than 10%. Moreover, the space potential and effective electron temperature calculated from electron energy distribution function measured by the FP is consistent with that measured by the CP over the operated discharge current and pressure ranges. These results present the FP can be used as a reliable diagnostic tool in the stable laboratory plasma and also be anticipated to be applied in other complicated plasmas, such as tokamaks, the region of boundary-layer, and so on.

  7. Spectra simulation of the argon plasma

    Microsoft Academic Search

    Z. Geng; K. Yao; Y. Zou

    2011-01-01

    In this work, a simulation calculation scheme based on a collisional radiation model and employing detailed energy levels was developed under the framework of corona approximation for low-density plasmas. Atomic data such as energy levels, radiative transition rates, Auger rates, collision excitation and ionization cross sections needed for the simulation were calculated by using the Flexible Atomic Code. In this

  8. Langmuir Probe Measurements of an Expanding Argon Plasma

    NASA Astrophysics Data System (ADS)

    Cao, Xiaogang; Xia, Yuxi; Chen, Bingzhou; Tian, Shuping; Wang, Chunling; Yang, Dangxiao; Xue, Xiaoyan; Zhang, Weiwei; Wang, Jianqiang; Gou, Fujun; Zhu, Zichuan; Ou, Wei; Chen, Shunli

    2015-01-01

    In this work, we studied the effects of the discharge current, gas flow rate and vessel pressure on the electron temperature and density of Ar plasma by Langmuir probe measurement. The argon plasma was created by a one-cathode arc source. The experimental results show that with increasing discharge current and gas flow rate, the electron temperature and density increase. It is found that when the discharge current is 70 A, 90 A and 110 A at an argon flow rate of 2000 sccm, the electron densities at about 0.186 m distance from the nozzle are 13.00×1018 m?3, 14.04×1018 m?3 and 15.62×1018 m?3, and the electron temperatures are 0.38 eV, 0.58 eV and 0.71 eV, respectively. The positive I-V characteristic is explained.

  9. Numerical Modeling of an RF Argon-Silane Plasma with Dust Particle Nucleation and Growth

    NASA Astrophysics Data System (ADS)

    Girshick, Steven; Agarwal, Pulkit

    2012-10-01

    We have developed a 1-D numerical model of an RF argon-silane plasma in which dust particles nucleate and grow. This model self-consistently couples a plasma module, a chemistry module and an aerosol module. The plasma module solves population balance equations for electrons and ions, the electron energy equation under the assumption of a Maxwellian velocity distribution, and Poisson's equation for the electric field. The chemistry module treats silane dissociation and reactions of silicon hydrides containing up to two silicon atoms. The aerosol module uses a sectional method to model particle size and charge distributions. The nucleation rate is equated to the rates of formation of anions containing two Si atoms, and a heterogeneous reaction model is used to model particle surface growth. Aerosol effects considered include particle charging, coagulation, and particle transport by neutral drag, ion drag, electric force, gravity and Brownian diffusion. Simulation results are shown for the case of a 13.56 MHz plasma at a pressure of 13 Pa and applied RF voltage of 100 V (amplitude), with flow through a showerhead electrode. These results show the strong coupling between the plasma and the spatiotemporal evolution of the nanoparticle cloud.

  10. Low Temperature Atmospheric Argon Plasma: Diagnostics and Medical Applications

    NASA Astrophysics Data System (ADS)

    Ermolaeva, Svetlana; Petrov, Oleg; Zigangirova, Nailya; Vasiliev, Mikhail; Sysolyatina, Elena; Antipov, Sergei; Alyapyshev, Maxim; Kolkova, Natalia; Mukhachev, Andrei; Naroditsky, Boris; Shimizu, Tetsuji; Grigoriev, Anatoly; Morfill, Gregor; Fortov, Vladimir; Gintsburg, Alexander

    This study was devoted to diagnostic of low temperature plasma produced by microwave generator and investigation of its bactericidal effect against bacteria in biofilms and within eukaryotic cells. The profile of gas temperature near the torch outlet was measured. The spectrum in a wide range of wavelengths was derived by the method of optical emission spec-troscopy. Probe measurements of the floating potential of plasma were car-ried out. The estimation and adaptation of parameters of plasma flow (tem-perature, velocity, ion number density) according to medico-technical requirements were produced. The model of immersed surface-associated biofilms formed by Gram-negative bacteria, Pseudomonas aeruginosa and Burkholderia cenocepacia, and Gram-positive bacteria, Staphylococcus aureus, was used to assess bactericidal effects of plasma treatment. Reduction in the concentration of live bacteria in biofilms treated with plasma for 5 min was demonstrated by measuring Live/Dead fluorescent labeling and using direct plating. The intracellular infection model with the pathogenic bacterium, Chlamydia trachomatis, was used to study the efficacy of microwave argon plasma against intracellular parasites. A 2 min plasma treatment of mouse cells infected with C. trachomatis reduced infectious bacteria by a factor of 2×106. Plasma treatment diminished the number of viable host cells by about 20%. When the samples were covered with MgF2 glass to obstruct active particles and UV alone was applied, the bactericidal effect was re-duced by 5×104 fold compared to the whole plasma.

  11. Laser induced fluorescence in a pulsed argon plasma Earl Scime,a)

    E-print Network

    Choueiri, Edgar

    Laser induced fluorescence in a pulsed argon plasma Earl Scime,a) Costel Biloiu, Christopher fluorescence (LIF) technique for pulsed argon plasmas is described. A low power, tunable diode laser pumps detection, i.e., using a lock-in amplifier. Pulsed plasmas present the additional challenge of requiring

  12. Fluid simulation of a pulsed-power inductively coupled argon plasma D. P. Lymberopoulos

    E-print Network

    Economou, Demetre J.

    Fluid simulation of a pulsed-power inductively coupled argon plasma D. P. Lymberopoulos Applied to investigate the spatiotemporal dynamics of a pulsed-power inductively coupled argon plasma at 10 m on the sheath thickness which is a complicated function of time in the pulsed plasma. For a constant time

  13. Plasma core reactor simulations using RF uranium seeded argon discharges

    NASA Technical Reports Server (NTRS)

    Roman, W. C.

    1975-01-01

    An experimental investigation was conducted using the United Technologies Research Center (UTRC) 80 kW and 1.2 MW RF induction heater systems to aid in developing the technology necessary for designing a self-critical fissioning uranium plasma core reactor (PCR). A nonfissioning, steady-state RF-heated argon plasma seeded with pure uranium hexafluoride (UF6) was used. An overall objective was to achieve maximum confinement of uranium vapor within the plasma while simultaneously minimizing the uranium compound wall deposition. Exploratory tests were conducted using the 80 kW RF induction heater with the test chamber at approximately atmospheric pressure and discharge power levels on the order of 10 kW. Four different test chamber flow configurations were tested to permit selection of the configuration offering the best confinement characteristics for subsequent tests at higher pressure and power in the 1.2 MW RF induction heater facility.

  14. Plasma core reactor simulations using RF uranium seeded argon discharges

    NASA Technical Reports Server (NTRS)

    Roman, W. C.

    1976-01-01

    Experimental results are described in which pure uranium hexafluoride was injected into an argon-confined, steady-state, RF-heated plasma to investigate characteristics of plasma core nuclear reactors. The 80 kW (13.56 MHz) and 1.2 MW (5.51 MHz) rf induction heater facilities were used to determine a test chamber flow scheme which offered best uranium confinement with minimum wall coating. The cylindrical fused-silica test chamber walls were 5.7-cm-ID by 10-cm-long. Test conditions included RF powers of 2-85 kW, chamber pressures of 1-12 atm, and uranium hexafluoride mass-flow rates of 0.005-0.13 g/s. Successful techniques were developed for fluid-mechanical confinement of RF-heated plasmas with pure uranium hexafluoride injection.

  15. Concerning Apparent Similarity of Structures of Fluoropolymer Surfaces Exposed to an Argon Plasma or Argon Ion Beam

    NASA Technical Reports Server (NTRS)

    Golub, Morton A.; Covington, M. Alan (Technical Monitor)

    1995-01-01

    X-ray photoelectron spectroscopy (XPS) C(sub 1s) spectra of fluoropolymers exposed to either an argon plasma or argon ion beam show remarkable similarity, implying that the surface-modification reactions for these two processes likely proceed through comparable mechanisms, revolving predominantly ion-surface interactions. The importance of working with a monochromatized x-ray source for XPS analysis of the surface-modified fluoropolymers is once again emphasized.

  16. In situ X-ray Photoemission Spectroscopy Analysis of Aromatic Polyester Surface Treated with Argon Plasma

    NASA Astrophysics Data System (ADS)

    Narushima, Kazuo; Okamoto, Nanami

    2013-10-01

    Effects of surface modification treatment by argon plasma processing of two types of aromatic polyester, poly(ethylene terephthalate) (PET) and poly(oxybenzonate-co-oxynaphthoate) (POCO), were investigated. This paper presents a description of our experiment and a discussion of the surface modification mechanism, which uses a simple and inexpensive procedure to conduct analysis without breaking vacuum after plasma processing. In situ analysis of the chemical composition of a polymer surface was attempted without exposing the sample to air after argon plasma processing. In particular, the respective actions of each active species were investigated for electrons and ions in argon plasma. Electrons and ions in argon plasma break some polymer bonds. Specifically, ester groups are broken and oxygen atoms are kicked out in PET and POCO. No oxygen functional group is formed after argon plasma processing, but such groups are formed if the sample is exposed to air.

  17. Detection of ozone in a MHz argon plasma bullet jet

    NASA Astrophysics Data System (ADS)

    Reuter, S.; Winter, J.; Iseni, S.; Peters, S.; Schmidt-Bleker, A.; Dünnbier, M.; Schäfer, J.; Foest, R.; Weltmann, K.-D.

    2012-06-01

    This study for the first time confirms the presence of plasma bullets in a MHz argon atmospheric pressure plasma jet. Bullet characteristics are investigated by phase-resolved optical emission measurements. Regarding the jet's reactive component output, its ozone production rates are investigated by two independent diagnostic techniques yielding complementary results. The first method—UV-absorption spectroscopy in the Hartley band—determines space-resolved distribution of the ozone concentration in the jet effluent. The second method—quantum cascade laser-absorption spectroscopy in the mid-infrared spectral region—yields high sensitivity results of the average ozone concentration in a multipass cell, in which the effluent is directed. The results of both diagnostic techniques show excellent agreement.

  18. Effect of the levitating microparticle cloud on radiofrequency argon plasma

    NASA Astrophysics Data System (ADS)

    Mitic, S.; Pustylnik, M. Y.; Klumov, B. A.; Morfill, G. E.

    2010-06-01

    The effect of a levitating cloud of microparticles on the parameters of a radiofrequency (RF) plasma has been studied by means of two experimental techniques. Axial distributions of 1s excited states of argon were measured by a self-absorption method. A correction of a standard self-absorption method for the extinction of the light by the levitating microparticles is proposed. In addition the electron temperature was estimated using the optical emission spectroscopy. Measurements at the same discharge conditions in a microparticle-free discharge and discharge, containing a cloud of levitating microparticles, revealed the non-local influence of the microparticle cloud on the discharge plasma. The most probable cause of this influence is the disturbance of the ionization balance by the levitating microparticles.

  19. Mesures du dplacement de la raie 703 nm de l'argon : application la dtermination de la densit lectronique dans un plasma d'argon

    E-print Network

    Paris-Sud XI, Université de

    527 Mesures du déplacement de la raie 703 nm de l'argon : application à la détermination de la densité électronique dans un plasma d'argon J. M. Badie, E. Billou et G. Vallbona Institut de Science et déplacement de la raie 703 nm de l'argon neutre en fonction de la densité électronique dans un arc d'argon

  20. Influence of dissociative recombination on the LTE of argon high-frequency plasmas at atmospheric pressure

    Microsoft Academic Search

    Abel Sainz; Joelle Margot; Maria Carmen Garcia; Maria Dolores Calzada

    2004-01-01

    This work presents a few preliminary results from a collisional-radiative (CR) model intended to describe an argon microwave (2.45 GHz) plasma at atmospheric pressure. This model aims to investigate the influence of dissociative recombination products on the Saha-Boltzmann plasma equilibrium. The model is tested through comparison with experimental results obtained in an argon plasma column generated by a traveling electromagnetic

  1. Surface treatment of para-aramid fiber by argon dielectric barrier discharge plasma at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Gu, Ruxi; Yu, Junrong; Hu, Chengcheng; Chen, Lei; Zhu, Jing; Hu, Zuming

    2012-10-01

    This paper is focused on influence of argon dielectric barrier discharge (DBD) plasma on the adhesive performance and wettability of para-aramid fibers and three parameters including treated power, exposure time and argon flux were detected. The interfacial shear strength (IFSS) was greatly increased by 28% with 300 W, 60 s, 2 L min-1 argon flux plasma treatment. The content of oxygen atom and oxygen-containing polar functional groups were enhanced after the argon plasma treated, so as the surface roughness, which contributed to the improvement of surface wettability and the decrease of contact angle with water. However, long-time exposure, exorbitant power or overlarge argon flux could partly destroy the prior effects of the treatment and damage the mechanical properties of fibers to some degree.

  2. Electrostatic waves in plasma: the case of an expanding microwave plasma sustained in argon

    NASA Astrophysics Data System (ADS)

    Jauberteau, J. L.; Jauberteau, I.

    2014-12-01

    This work is devoted to the study of the electrostatic wave dispersion in plasma. Investigations are focused on waves with angular frequency ranging between the ion and the electron angular resonance frequency. The dispersion equation is resolved by means of a Fourier transform spectral method in the case of theoretical Maxwell–Boltzmann electron energy distribution functions (EEDFs), and in the case of experimental EEDFs measured by means of a Langmuir probe in microwave expanding plasma sustained in argon. The results show the change of the dispersion curve with the plasma parameters and the role of electrons and ions in the shape of the dispersion curve.

  3. Mechanism of Blood Coagulation by Nonthermal Atmospheric Pressure Dielectric Barrier Discharge Plasma

    Microsoft Academic Search

    Sameer U. Kalghatgi; Gregory Fridman; Moogega Cooper; Gayathri Nagaraj; Marie Peddinghaus; Manjula Balasubramanian; Victor N. Vasilets; Alexander F. Gutsol; Alexander Fridman; Gary Friedman

    2007-01-01

    Mechanisms of blood coagulation by direct contact of nonthermal atmospheric pressure dielectric barrier discharge (DBD) plasma are investigated. This paper shows that no significant changes occur in the pH or Ca2+ concentration of blood during discharge treatment. Thermal effects and electric field effects are also shown to be negligible. Investigating the hypothesis that the discharge treatment acts directly on blood

  4. Atmospheric Pressure Humid Argon DBD Plasma for the Application of Sterilization -Measurement and Simulation of Hydrogen, Oxygen, and Hydrogen

    E-print Network

    Paris-Sud XI, Université de

    Atmospheric Pressure Humid Argon DBD Plasma for the Application of Sterilization - Measurement peroxide have been measured downstream of an atmospheric pressure humid argon dielectric barrier discharge. The results of experiments on the use of post-discharge effluent gas of humid argon plasma for sterilization

  5. Measurements and modeling of ion and neutral distribution functions in a partially ionized magnetically confined argon plasma

    E-print Network

    Howard, John

    magnetically confined argon plasma C. A. Michael,a) J. Howard, and B. D. Blackwell PRL, RSPhysSE, Australian is studied in low field ( 0.15 T) rf heated argon discharges of the H-1 Heliac S. M. Hamberger, B. D) argon discharges of the H-1 Heliac,3 where the plasma is produced and the electrons are heated

  6. Particle modeling of non-collisional heating in inductively coupled argon plasmas

    Microsoft Academic Search

    H. Takekida; K. Nanbu

    2006-01-01

    The effect of non-collisional heating on inductively coupled argon plasma is examined using the particle modeling. The effect is clarified by comparing the plasma densities obtained using two types of plasma current; one is the warm current directly sampled from the velocities of electrons and the other is the cold current given by Ohm's law. The calculation is performed for

  7. Research on Surface Modification of Polytetrafluoroethylene Coupled With Argon Dielectric Barrier Discharge Plasma Jet Characteristics

    Microsoft Academic Search

    Xian-Jun Shao; Guan-Jun Zhang; Jiang-Yang Zhan; Gui-Min Xu

    2011-01-01

    An argon dielectric barrier discharge (DBD) atmospheric-pressure plasma jet (APPJ) is designed and employed for surface modification of polytetrafluoroethylene (PTFE). The plasma diagnostics and dielectric surface analysis are coupled together to investigate the mechanisms of plasma modification. The discharge power is obtained by Lissajous figure, and electron excitation temperature (EET) is measured through an optical emission spectrum and calculated by

  8. Influence of oxygen traces on an atmospheric-pressure radio-frequency capacitive argon plasma discharge

    SciTech Connect

    Li Shouzhe; Wu Qi; Yan Wen; Wang Dezhen [Key Laboratory of Materials Modification by Laser, Ion, Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China) and School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China); Uhm, Han S. [Kwangwoon Academy of Advanced Studies, Kwangwoon University, 447-1 Wolgye-dong, Nowon-gu, Seoul 137-701 (Korea, Republic of)

    2011-10-15

    An atmospheric-pressure capacitive discharge source driven by radio-frequency power supply at 13.56 MHz has been developed experimentally that is capable of producing a homogeneous and cold glow discharge in O{sub 2}/Ar. With respect to the influence of oxygen component when diluted into argon plasma discharge on the discharge characteristics, the measurements of the electrical parameters (impedance, phase angle, resistance, and reactance) are made systematically and the densities of the metastable and resonant state of argon are determined by means of optical emission spectroscopy (OES). It is shown that the admixture of oxygen into argon plasma not only changes the electric characteristics but also alters the optical emission spectra greatly due to strong interaction between the oxygen content and the argon in the plasma environment.

  9. Characteristics of a non-Maxwellian electron energy distribution in a low-pressure argon plasma

    NASA Astrophysics Data System (ADS)

    Park, Seolhye; Choe, Jae-Myung; Roh, Hyun-Joon; Kim, Gon-Ho

    2014-06-01

    The generality of the non-Maxwellian electron energy distribution function (EEDF) is demonstrated by using optical emission spectroscopy (OES) and Langmuir probe measurements in inductively- and capacitively-coupled low-pressure argon plasmas to analyze the shape factor of the EEDF. To measure the shape factor of the EEDF, we propose a corona — equilibrium (CE) — based analysis model operating at low density, which uses the line intensity ratio of the Ar I to the Ar II emission lines. The Ar I line is chosen to represent the relatively low-energy state, and the Ar II line is chosen to represent the high-energy state. Thus, an analysis of the shape factor is equivalent to monitoring the variation in the high-energy electron fraction represented in the tail of the EEDF. Results show a depleted tail for the Maxwellian distribution in most of the low-density argon plasmas. The analysis reveals that the generation and the stepwise ionization of metastable argon atoms by inelastic collisions with high-energy (˜ 10 eV) electrons are dominant processes of argon plasma generation and cause serious high-energy electron loss in a low-density system compared to the loss in an ideal Maxwellian plasma. The existence of argon metastable states is inevitable; thus, the general shape of the electron energy distribution in low-pressure argon plasmas is non-Maxwellian.

  10. Effects of water addition on OH radical generation and plasma properties in an atmospheric argon microwave plasma jet

    Microsoft Academic Search

    Nimisha Srivastava; Chuji Wang

    2011-01-01

    Water vapor was added to the feeding gas of a continuous atmospheric argon (Ar) microwave plasma jet to study its influence on plasma shape, plasma gas temperature, and OH radical concentrations. The plasma jet was created by a 2.45 GHz microwave plasma source operating at constant power of 104 W with H2O-Ar mixture flow rate of 1.7 standard liter per

  11. Comparison of functional aspects of the coagulation cascade in human and sea turtle plasmas.

    PubMed

    Soslau, Gerald; Wallace, Bryan; Vicente, Catherine; Goldenberg, Seth J; Tupis, Todd; Spotila, James; George, Robert; Paladino, Frank; Whitaker, Brent; Violetta, Gary; Piedra, Rotney

    2004-08-01

    Functional hemostatic pathways are critical for the survival of all vertebrates and have been evolving for more than 400 million years. The overwhelming majority of studies of hemostasis in vertebrates have focused on mammals with very sparse attention paid to reptiles. There have been virtually no studies of the coagulation pathway in sea turtles whose ancestors date back to the Jurassic period. Sea turtles are often exposed to rapidly altered environmental conditions during diving periods. This may reduce their blood pH during prolonged hypoxic dives. This report demonstrates that five species of turtles possess only one branch of the mammalian coagulation pathway, the extrinsic pathway. Mixing studies of turtle plasmas with human factor-deficient plasmas indicate that the intrinsic pathway factors VIII and IX are present in turtle plasma. These two factors may play a significant role in supporting the extrinsic pathway by feedback loops. The intrinsic factors, XI and XII are not detected which would account for the inability of reagents to induce coagulation via the intrinsic pathway in vitro. The analysis of two turtle factors, factor II (prothrombin) and factor X, demonstrates that they are antigenically/functionally similar to the corresponding human factors. The turtle coagulation pathway responds differentially to both pH and temperature relative to each turtle species and relative to human samples. The coagulation time (prothrombin time) increases as the temperature decreases between 37 and 15 degrees C. The increased time follows a linear relationship, with similar slopes for loggerhead, Kemps ridley and hawksbill turtles as well as for human samples. Leatherback turtle samples show a dramatic nonlinear increased time below 23 degrees C, and green turtle sample responses were similar but less dramatic. All samples also showed increased prothrombin times as the pH decreased from 7.8 to 6.4, except for three turtle species. The prothrombin times decreased, to varying extents, in a linear fashion relative to reduced pH with the rate of change greatest in leatherbacks>green>loggerhead turtles. All studies were conducted with reagents developed for human samples which would impact on the quantitative results with the turtle samples, but are not likely to alter the qualitative results. These comparative studies of the coagulation pathway in sea turtles and humans could enhance our knowledge of structure/function relationships and evolution of coagulation factors. PMID:15325341

  12. A pulse-modulated nonequilibrium atmospheric-pressure microwave argon plasma discharge preionized by a kilohertz excited plasma jet

    SciTech Connect

    Li Shouzhe; Xu Maochun; Zhang Xin; Zhang Jialiang [Key Laboratory of Materials Modification by Laser, Ion, Electron Beams, Ministry of Education, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2012-04-23

    A pulse-modulated nonequilibrium atmospheric-pressure microwave argon surface wave plasma is generated by means of a preionization discharge with a single-electrode plasma jet driven by a power supply of 50 kHz. It is found that the electron induced Saha-like balance dominates excitation process in the plasma discharge through the electron temperature varying with the microwave input power and the applied voltage of kilohertz power supply. The microwave pulse-modulating effect on nonequilibrium characteristics of dual-frequency exciting argon surface wave plasma is studied by spectroscopic measurement of the excitation temperature and gas temperature.

  13. Non-local thermodynamic equilibrium effects on isentropic coefficient in argon and helium thermal plasmas

    SciTech Connect

    Sharma, Rohit [Satyam Institute of Engineering and Technology, Amritsar 143107 (India)] [Satyam Institute of Engineering and Technology, Amritsar 143107 (India); Singh, Kuldip [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India)] [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India)

    2014-03-15

    In the present work, two cases of thermal plasma have been considered; the ground state plasma in which all the atoms and ions are assumed to be in the ground state and the excited state plasma in which atoms and ions are distributed over various possible excited states. The variation of Z?, frozen isentropic coefficient and the isentropic coefficient with degree of ionization and non-equilibrium parameter ?(= T{sub e}/T{sub h}) has been investigated for the ground and excited state helium and argon plasmas at pressures 1?atm, 10?atm, and 100?atm in the temperature range from 6000?K to 60?000?K. For a given value of non-equilibrium parameter, the relationship of Z? with degree of ionization does not show any dependence on electronically excited states in helium plasma whereas in case of argon plasma this dependence is not appreciable till degree of ionization approaches 2. The minima of frozen isentropic coefficient shifts toward lower temperature with increase of non-equilibrium parameter for both the helium and argon plasmas. The lowering of non-equilibrium parameter decreases the frozen isentropic coefficient more emphatically in helium plasma at high pressures in comparison to argon plasma. The increase of pressure slightly reduces the ionization range over which isentropic coefficient almost remains constant and it does not affect appreciably the dependence of isentropic coefficient on non-equilibrium parameter.

  14. MESURE DE LA TEMPRATURE DES PARTICULES LOURDES DANS UN JET DE PLASMA D'ARGON SOUS PRESSION (*)

    E-print Network

    Boyer, Edmond

    1187 MESURE DE LA TEMP�RATURE DES PARTICULES LOURDES DANS UN JET DE PLASMA D'ARGON SOUS PRESSION mesurer la tem- pérature atomique T0 d'un plasma d'argon faiblement ionisé (degré d'ionisation ~ 10-4, Ne ionized argon plasma (ionisation degree ~ 10-4, Ne ~ 1014 cm-3, Te ~ 6 000 K) for pressures ranging from 1

  15. Inhibition of vascular permeability by antisense-mediated inhibition of plasma kallikrein and coagulation factor 12.

    PubMed

    Bhattacharjee, Gourab; Revenko, Alexey S; Crosby, Jeffrey R; May, Chris; Gao, Dacao; Zhao, Chenguang; Monia, Brett P; MacLeod, A Robert

    2013-06-01

    Hereditary angioedema (HAE) is a rare disorder characterized by recurrent, acute, and painful episodes of swelling involving multiple tissues. Deficiency or malfunction of the serine protease inhibitor C1 esterase inhibitor (C1-INH) results in HAE types 1 and 2, respectively, whereas mutations in coagulation factor 12 (f12) have been associated with HAE type 3. C1-INH is the primary inhibitor of multiple plasma cascade pathways known to be altered in HAE patients, including the complement, fibrinolytic, coagulation, and kinin-kallikrein pathways. We have selectively inhibited several components of both the kinin-kallikrein system and the coagulation cascades with potent and selective antisense oligonucleotides (ASOs) to investigate their relative contributions to vascular permeability. We have also developed ASO inhibitors of C1-INH and characterized their effects on vascular permeability in mice as an inducible model of HAE. Our studies demonstrate that ASO-mediated reduction in C1-INH plasma levels results in increased vascular permeability and that inhibition of proteases of the kinin-kallikrein system, either f12 or prekallikrein (PKK) reverse the effects of C1-INH depletion with similar effects on both basal and angiotensin converting enzyme (ACE) inhibitor-induced permeability. In contrast, inhibition of coagulation factors 11 (f11) or 7 (f7) had no effect. These results suggest that the vascular defects observed in C1-INH deficiency are dependent on the kinin-kallikrein system proteases f12 and PKK, and not mediated through the coagulation pathways. In addition, our results highlight a novel therapeutic modality that can potentially be employed prophylactically to prevent attacks in HAE patients. PMID:23582057

  16. Nucleation of silicon nanocrystals in a remote plasma without subsequent coagulation

    NASA Astrophysics Data System (ADS)

    Do?an, Ilker; Weeks, Stephen L.; Agarwal, Sumit; van de Sanden, Mauritius C. M.

    2014-06-01

    We report on the growth mechanism of spherical silicon nanocrystals in a remote expanding Ar plasma using a time-modulated SiH4 gas injection in the microsecond time range. Under identical time-modulation parameters, we varied the local density of the SiH4 gas by changing its stagnation pressure on the injection line over the range of 0.1-2.0 bar. We observed that nanocrystals were synthesized in a size range from ˜2 to ˜50 nm with monocrystalline morphology. Smaller nanocrystals (˜2-6 nm) with narrower size distributions and with higher number densities were synthesized with an increase of the SiH4 gas-phase density. We related this observation to the rapid depletion of the number density of the molecules, ions, and radicals in the plasma during nanocrystal growth, which can primarily occur via nucleation with no significant subsequent coagulation. In addition, in our remote plasma environment, rapid cooling of the gas in the particle growth zone from ˜1500 to ˜400 K significantly reduces the coalescence rate of the nanoparticles, which makes the coagulation process highly unlikely. Our observations on nanocrystal formation via nucleation indicated that subsequent coagulation for further growth is not always an essential step on nanoparticle formation.

  17. Effect of snake venom procoagulants on snake plasma: implications for the coagulation cascade of snakes.

    PubMed

    Joseph, Jeremiah S; Chung, Maxey C M; Mirtschin, Peter J; Kini, R Manjunatha

    2002-02-01

    Several snake venoms contain proteinases that activate zymogens in the coagulation cascade and thus exhibit their procoagulant effects. While most procoagulant proteinases from snake venoms are dissimilar to coagulation factors, Group D (trocarin, notecarin) and C (pseutarin) prothrombin activators are structural and functional homologues of factor Xa and the prothrombinase complex, respectively. We examined the effect of these and other procoagulants from snake venoms as well as mammalian and snake thromboplastins on the coagulation of plasmas of Notechis scutatus, Pseudonaja textilis (both procoagulant venoms), Python reticulatus (non-venomous) and Crotalus atrox (non-procoagulant venom) snakes. The results indicate that the intrinsic pathway seems to be weak or absent only in venomous snakes, while the extrinsic pathway is fully functional in all snakes. Python and Crotalus plasmas have extrinsic pathways similar to that in mammals. In contrast, although Notechis and Pseudonaja plasmas were clotted by a Group C activator, they failed to clot upon the addition of factor Xa and Group D activators. The mechanism of this resistance is still elusive. PMID:11689239

  18. Numerical simulation of alumina spraying in argon-helium plasma jet

    SciTech Connect

    Chang, C.H.

    1992-08-01

    A new numerical model is described for simulating thermal plasmas containing entrained particles, with emphasis on plasma spraying applications. The plasma is represented as a continuum multicomponent chemically reacting ideal gas, while the particles are tracked as discrete Lagrangian entities coupled to the plasma. Computational results are presented from a transient simulation of alumina spraying in a turbulent argon-helium plasma jet in air environment, including torch geometry, substrate, and multiple species with chemical reactions. Particle-plasma interactions including turbulent dispersion have been modeled in a fully self-consistent manner. Interactions between the plasma and the torch and substrate walls are modeled using wall functions. (15 refs.)

  19. Numerical simulation of alumina spraying in argon-helium plasma jet

    SciTech Connect

    Chang, C.H.

    1992-01-01

    A new numerical model is described for simulating thermal plasmas containing entrained particles, with emphasis on plasma spraying applications. The plasma is represented as a continuum multicomponent chemically reacting ideal gas, while the particles are tracked as discrete Lagrangian entities coupled to the plasma. Computational results are presented from a transient simulation of alumina spraying in a turbulent argon-helium plasma jet in air environment, including torch geometry, substrate, and multiple species with chemical reactions. Particle-plasma interactions including turbulent dispersion have been modeled in a fully self-consistent manner. Interactions between the plasma and the torch and substrate walls are modeled using wall functions. (15 refs.)

  20. Comparison of excitation temperature and electron temperature in low pressure argon plasmas

    Microsoft Academic Search

    Junkyu Rhee; Junghee Kim; Jongsub Lee; Seonghun Lee; Shinjae You; Hongyoung Chang; Wonho Choe

    2006-01-01

    Compared to other active diagnostic methods, the optical emission spectroscopy (OES) method using an emission spectrum from the plasmas has a benefit of non-intrusive, in-situ monitoring of the plasmas. In this work, a study was performed to investigate the relation between the excitation temperature (obtained by OES) and the electron temperature (obtained by a Langmuir probe) in low pressure argon

  1. Laser light scattering in a laser-induced argon plasma: Investigations of the B. Pokrzywka a

    E-print Network

    . Introduction Laser-induced plasma (LIP) is an object of great interest, as it gives insight and complimentary experimental approach in LIP studies is the application of active laser methods: Raman, RayleighLaser light scattering in a laser-induced argon plasma: Investigations of the shock wave B

  2. Investigations of laser-induced plasma in argon by Thomson scattering A. Mendys a,

    E-print Network

    as of the electron density (ne) and electron temperature (Te). For laser induced plasma (LIP), the electron densityInvestigations of laser-induced plasma in argon by Thomson scattering A. Mendys a, , K. Dzierega Accepted 8 August 2011 Available online 16 August 2011 Keywords: Laser-induced breakdown spectroscopy

  3. Measurement of Metastable Atom Populations Along an Argon Plasma Column Generated at Atmospheric Pressure

    Microsoft Academic Search

    Isabel Santiago; MarÍa Dolores Calzada

    2009-01-01

    This paper describes a procedure for experimental determination of metastable and resonant populations along a surface wave argon plasma column at atmospheric pressure. As modeling work progresses extensively, an experimental database is necessary to confirm these models. Obtained results, within the range of values reported in literature, indicate that densities of metastable and resonant levels grow along the plasma column

  4. Heat transfer between tungsten surface and glow discharge plasmas in argon and CO 2

    Microsoft Academic Search

    F. D. Polikarpov; A. F. Polikarpov; S. F. Borisov; S. P. Nikulin; P. V. Tretnikov

    2009-01-01

    A hot-filament method is used to study the heat transfer between tungsten surface and hollow-cathode glow discharge plasmas\\u000a in argon and CO2. The dependence of the electric power supplied to a tungsten wire on the discharge current is determined for argon and carbon\\u000a dioxide in the temperature range between 1000 and 1700 K. A difference in heat transfer at the

  5. Inactivation of human immunodeficiency virus by gamma radiation and its effect on plasma and coagulation factors

    SciTech Connect

    Hiemstra, H.; Tersmette, M.; Vos, A.H.; Over, J.; van Berkel, M.P.; de Bree, H. (Central Laboratory of The Netherlands, Red Cross Blood Transfusion Service, Amsterdam (Netherlands))

    1991-01-01

    The inactivation of HIV by gamma-radiation was studied in frozen and liquid plasma; a reduction of the virus titer of 5 to 6 logs was achieved at doses of 5 to 10 Mrad at -80 degrees C and 2.5 Mrad at 15 degrees C. The effect of irradiation on the biologic activity of a number of coagulation factors in plasma and in lyophilized concentrates of factor VIII (FVIII) and prothrombin complex was examined. A recovery of 85 percent of the biologic activity of therapeutic components present in frozen plasma and in lyophilized coagulation factor concentrates was reached at radiation doses as low as 1.5 and 0.5 Mrad, respectively. As derived from the first-order radiation inactivation curves, the radiosensitive target size of HIV was estimated to be 1 to 3 MDa; the target size of FVIII was estimated to be 130 to 160 kDa. Gamma radiation must be disregarded as a method for the sterilization of plasma and plasma-derived products, because of the low reduction of virus infectivity at radiation doses that still give acceptable recovery of biologic activity of plasma components.

  6. Comparative Study of Plasma Parameters in Magnetic Pole Enhanced Inductively Coupled Argon Plasmas

    NASA Astrophysics Data System (ADS)

    F., Jan; W. Khan, A.; Saeed, A.; Zakaullah, M.

    2013-04-01

    Langmuir probe measurements of radio frequency (RF) magnetic pole enhanced inductively coupled (MaPE-ICP) argon plasma were accomplished to obtain the electron number densities and electron temperatures. The measurements were carried out with a fixed RF frequency of 13.56 MHz in a pressure range of 7.5 mTorr to 75 mTorr at an applied RF power of 10 W and 100 W. These results are compared with a global (volume average) model. The results show good agreement between theoretical and experimental measurements. The electron number density shows an increasing trend with both RF power and pressure while the electron temperature shows decreasing trend as the pressure increases. The difference in the plasma potential and floating potential as a function of electron temperature measured from the electrical probe and that obtained theoretically shows a linear relation with a small difference in the coefficient of proportionality. The intensity of the emission line at 750.4 nm due to 2p1 ? 1s2 (Paschen's notation) transition closely follows the variation of ne with RF power and filling gas pressure. Measured electron energy probability function (EEPF) shows that electron occupation changes mostly in the high-energy tail, which highlights close similarity of 750.4 nm argon line to ne.

  7. Modeling and simulation of ion-filtered inductively coupled plasma using argon plasma

    NASA Astrophysics Data System (ADS)

    Wu, Chao; Wang, Jian; Zhang, Weiwang; Luo, Yi

    2015-03-01

    An ion-filtered inductively coupled plasma (IF-ICP) is proposed to reduce ion bombardment and provide high metastable species density for chemical vapor deposition. Argon plasma, which has simple reaction mechanism, is simulated to show the effects of ion filter. Compared to typical ICP, the maximum density of ions of IF-ICP is lower while that of metastable species is higher. The filter can absorb ions effectively and relatively small amount of metastable species, with the absorption coefficient proportional to its surface area. A proper gap between filter and substrate can achieve more metastable species and less ions on the substrate. The pressure and RF power need to be optimized based on the tradeoff between deposition rate and ion damage. The density of ions on the substrate can be reduced by two orders of magnitude while that of metastable species are maintained in the order of 1017 m?3 under the optimized conditions.

  8. TUDE EXPRIMENTALE DE L'MISSION DE BREMSSTRAHLUNG LECTRON ATOME DANS UN JET DE PLASMA D'ARGON

    E-print Network

    Boyer, Edmond

    1829 �TUDE EXP�RIMENTALE DE L'�MISSION DE BREMSSTRAHLUNG �LECTRON ATOME DANS UN JET DE PLASMA D'ARGON,4 03BCm et 5 03BCm sur un jet de plasma d'argon faiblement ionisé en cours de recombinaison between 0.4 03BCm and 5 03BCm in a decay- ing argon plasmajet ; in visible and infra-red range, some

  9. Sterilization of Bacillus subtilis Spores Using an Atmospheric Plasma Jet with Argon and Oxygen Mixture Gas

    NASA Astrophysics Data System (ADS)

    Shen, Jie; Cheng, Cheng; Fang, Shidong; Xie, Hongbing; Lan, Yan; Ni, Guohua; Meng, Yuedong; Luo, Jiarong; Wang, Xiangke

    2012-03-01

    To determine an efficient sterilization mechanism, Bacillus subtilis spore samples were exposed to an atmospheric plasma jet. By using argon/oxygen mixture gas, the decimal reduction value was reduced from 60 s (using argon gas) to 10 s. More dramatically, after 5 min treatment, the colony-forming unit (CFU) was reduced by six orders. To understand the underlying mechanism of the efficient sterilization by plasma, the contributions from heat, UV radiation, charged particles, ozone, and reactive oxygen radicals were distinguished in this work, showing that charged particles and ozone were the main killing factors. The shape changes of the spores were also discussed.

  10. Microwave diagnostic for the determination of the electron temperature of a low density shock-heated argon plasma

    Microsoft Academic Search

    C. P. Schneider; R. J. Exberger

    1978-01-01

    The diffraction, defocusing and beam bending effects of microwaves transmitted through a bounded shock-heated argon plasma with low electron density are investigated with the purpose of developing an accurate method for electron temperature (Te) determination. This report describes the evaluation technique and presents results for an argon plasma with pressure between 3 and 10 torr, and T2 between 5500 and

  11. Surface modification of fluorosilicone acrylate RGP contact lens via low-temperature argon plasma

    NASA Astrophysics Data System (ADS)

    Yin, Shiheng; Wang, Yingjun; Ren, Li; Zhao, Lianna; Kuang, Tongchun; Chen, Hao; Qu, Jia

    2008-11-01

    A fluorosilicone acrylate rigid gas permeable (RGP) contact lens was modified via argon plasma to improve surface hydrophilicity and resistance to protein deposition. The influence of plasma treatment on surface chemical structure, hydrophilicity and morphology of RGP lens was investigated by X-ray photoelectron spectrometer (XPS), contact angle measurements and scanning electron microscope (SEM), respectively. The contact angle results showed that the hydrophilicity of the contact lens was improved after plasma treatment. XPS results indicated that the incorporation of oxygen-containing groups on surface and the transformation of silicone into hydrophilic silicate after plasma treatment are the main reasons for the surface hydrophilicity improvement. SEM results showed that argon plasma with higher power could lead to surface etching.

  12. Measurement Of The Distribution Of Ionization States In An Argon Plasma

    NASA Astrophysics Data System (ADS)

    Fisher, T. R.; Filbert, P. C.; Kohler, D.; Perez, J. D.; Walton, R.; Dahlbacka, G.

    1988-02-01

    An experiment to measure the distribution of ionization states in an argon plasma proliaced by irradiating a gas-jet with 351-nm radiation from the OMEGA laser is described. The gas-jet was provided by Plasma Research Corporation. Its low divergence makes it possible to create a disk-shaped plasma region 1.5 mm diam x 1.5 mm thick over which the temperature and density are slowly varying. The experiment was performed at the Laboratory for Laser Energetics, University of Rochester, as part of the Department of energy's National Laser Users Facility Program. Eight beams of 60 J each were used to teat the argon gas-jet plasma. In the present experiment, a plasma temperature of about 65 eV was achieved at an electron density of about 1.0 x 1018. Lines in argon charge states VIII-XI have been ileatified in the spectra, and the results are compared with theoretical models which ,directly solve the time-dependent charge-state rate equations. It was found necessary to preionize the argon in order to couple in sufficient energy from the laser to produce a plasmasma.

  13. Ionic Wind Phenomenon and Charge Carrier Mobility in Very High Density Argon Corona Discharge Plasma

    NASA Astrophysics Data System (ADS)

    Nur, M.; Bonifaci, N.; Denat, A.

    2014-04-01

    Wind ions phenomenon has been observed in the high density argon corona discharge plasma. Corona discharge plasma was produced by point to plane electrodes and high voltage DC. Light emission from the recombination process was observed visually. The light emission proper follow the electric field lines that occur between point and plane electrodes. By using saturation current, the mobilities of non-thermal electrons and ions have been obtained in argon gas and liquid with variation of density from 2,5 1021 to 2 1022 cm-3. In the case of ions, we found that the behaviour of the apparent mobility inversely proportional to the density or follow the Langevin variation law. For non-thermal electron, mobility decreases and approximately follows a variation of Langevin type until the density <= 0,25 the critical density of argon.

  14. Dysregulated coagulation associated with hypofibrinogenemia and plasma hypercoagulability: implications for identifying coagulopathic mechanisms in humans

    PubMed Central

    Marchi, Rita; Walton, Bethany L.; McGary, Colleen S.; Lin, Feng-Chang; Ma, Alice D.; Pawlinski, Rafal; Mackman, Nigel; Campbell, Robert A.; Di Paola, Jorge; Wolberg, Alisa S.

    2013-01-01

    SUMMARY Identifying coagulation abnormalities in patients with combined bleeding and thrombosis history is clinically challenging. Our goal was to probe the complexity of dysregulated coagulation in humans by characterizing pathophysiologic mechanisms in a patient with both bleeding and thrombosis. The patient is a 56-year old female with a history of hematomas, poor wound healing, and thrombosis (retinal artery occlusion and transient cerebral ischemia). She had a normal activated partial thromboplastin time, prolonged thrombin and reptilase times, and decreased functional and antigenic fibrinogen levels, and was initially diagnosed with hypodysfibrinogenemia. This diagnosis was supported by DNA analysis revealing a novel FGB mutation (c.656A>G) predicting a Q189R mutation in the mature B? chain that was present in the heterozygote state. However, turbidity analysis showed that purified fibrinogen polymerization and degradation were indistinguishable from normal, and B? chain subpopulations appeared normal by two-dimensional difference in-gel electrophoresis, indicating the mutated chain was not secreted. Interestingly, plasma thrombin generation testing revealed the patient’s thrombin generation was higher than normal and could be attributed to elevated levels of factor VIII (FVIII, 163-225%). Accordingly, in an arterial injury model, hypofibrinogenemic mice (Fgn+/?) infused with FVIII demonstrated significantly shorter vessel occlusion times than saline-infused Fgn+/? mice. Together, these data associate the complex bleeding and thrombotic presentation with combined hypofibrinogenemia plus plasma hypercoagulability. These findings suggest previous cases in which fibrinogen abnormalities have been associated with thrombosis may also be complicated by co-existing plasma hypercoagulability and illustrate the importance of “global” coagulation testing in patients with compound presentations. PMID:22836883

  15. Characterization of a low-pressure argon plasma using optical emission spectroscopy and a global model

    NASA Astrophysics Data System (ADS)

    Palmero, A.; van Hattum, E. D.; Rudolph, H.; Habraken, F. H. P. M.

    2007-03-01

    The excitation mechanisms of the lower lying excited levels in a low-ionized, low-pressure, argon plasma are modeled and studied in order to characterize the plasma through optical emission spectroscopy. It is found that the lower lying excited states of argon play an important role in the excitation and that they must be taken explicitly into account for an accurate determination of the excitation rates. The possible influence of radiative cascades from upper argon excited states, which are not included in the model, has been studied by introducing an effective level in the description and studying its influence on the results. The model has been used to calculate the electron density and electron temperature in an argon magnetron sputtering plasma produced at different electromagnetic powers and gas pressures, as a function of the intensity of the optical emission lines ?1=750.38nm and ?2=696.54nm. The results obtained from the model have been compared with Langmuir probe measurements, showing a good agreement. It is hereby demonstrated that optical emission spectroscopy can be used to monitor the plasma properties during the deposition process when applying a nonlinear model.

  16. Characterization of a low-pressure argon plasma using optical emission spectroscopy and a global model

    SciTech Connect

    Palmero, A.; Hattum, E. D. van; Rudolph, H.; Habraken, F. H. P. M. [Surfaces, Interfaces and Devices, Department of Physics and Astronomy, Utrecht University, P.O. Box 80.000, 3508TA Utrecht (Netherlands)

    2007-03-01

    The excitation mechanisms of the lower lying excited levels in a low-ionized, low-pressure, argon plasma are modeled and studied in order to characterize the plasma through optical emission spectroscopy. It is found that the lower lying excited states of argon play an important role in the excitation and that they must be taken explicitly into account for an accurate determination of the excitation rates. The possible influence of radiative cascades from upper argon excited states, which are not included in the model, has been studied by introducing an effective level in the description and studying its influence on the results. The model has been used to calculate the electron density and electron temperature in an argon magnetron sputtering plasma produced at different electromagnetic powers and gas pressures, as a function of the intensity of the optical emission lines {lambda}{sub 1}=750.38 nm and {lambda}{sub 2}=696.54 nm. The results obtained from the model have been compared with Langmuir probe measurements, showing a good agreement. It is hereby demonstrated that optical emission spectroscopy can be used to monitor the plasma properties during the deposition process when applying a nonlinear model.

  17. Transport coefficients of air, argon-air, nitrogen-air, and oxygen-air plasmas

    Microsoft Academic Search

    A. B. Murphy

    1995-01-01

    Calculated values of the viscosity, thermal conductivity and electrical conductivity of air and mixtures of air and argon, air and nitrogen, and air and oxygen at high temperatures are presented. In addition, combined ordinary, pressure, and thermal diffusion coefficients are given for the gas mixtures. The calculations, which assione local thermodynamic equilibrium, are performed for atmospheric pressure plasmas in the

  18. Inductively coupled argon plasma as an ion source for mass spectrometric determination of trace elements

    Microsoft Academic Search

    Robert S. Houk; Velmer A. Fassel; Gerald D. Flesch; Harry J. Svec; Alan L. Gray; Charles E. Taylor

    1980-01-01

    Solution aerosols are injected into an inductively coupled argon plasma (ICP) to generate a relativly high number density of positive ions derived from elemental constituents. A small fraction of these ions is extracted through a sampling orifice into a differentially pumped vacuum system housing an ion lens and quadrupole mass spectrometer. The positive ion mass spectrum obtained during nebulization of

  19. INDUCTIVELY COUPLED ARGON PLASMA AS AN ION SOURCE FOR MASS SPECTROMETRIC DETERMINATION OF TRACE ELEMENTS

    EPA Science Inventory

    Solution aerosols are injected into an inductively coupled argon plasma (ICP) to generate a relatively high number density of positive ions derived from elemental constituents. A small fraction of these ions is extracted through a sampling orifice into a differentially pumped vac...

  20. Role of dissociative recombination in the excitation kinetics of an argon microwave plasma at atmospheric pressure

    Microsoft Academic Search

    A. Sa´inz; J. Margot; M. C. Garci´a; M. D. Calzada

    2005-01-01

    A collisional radiative model was developed in order to investigate the influence of dissociative recombination on the Saha–Boltzmann plasma equilibrium. As the dissociative recombination products are not well known, their relative importance was tested through comparison with the distribution of line intensities obtained in a microwave argon discharge produced at atmospheric pressure by a surface wave. It was found that

  1. Role of dissociative recombination in the excitation kinetics of an argon microwave plasma at atmospheric pressure

    Microsoft Academic Search

    A. Sáinz; J. Margot; M. C. García; M. D. Calzada

    2005-01-01

    A collisional radiative model was developed in order to investigate the influence of dissociative recombination on the Saha-Boltzmann plasma equilibrium. As the dissociative recombination products are not well known, their relative importance was tested through comparison with the distribution of line intensities obtained in a microwave argon discharge produced at atmospheric pressure by a surface wave. It was found that

  2. Theoretical Study of Plasma Parameters Dependence on Gas Temperature in an Atmospheric Pressure Argon Microwave Discharge

    Microsoft Academic Search

    M. Pencheva; E. Benova; I. Zhelyazkov

    2008-01-01

    The gas temperature is an important parameter in many applications of atmospheric pressure microwave discharges (MW). That is why it is necessary to study the influence of that temperature on the plasma characteristics. Our investigation is based on a self-consistent model including the wave electrodynamics and gas-discharge kinetics. We adopt a blocks' energy structure of the argon excited atom. More

  3. Gas Temperature Determination in Argon-Helium Plasma at Atmospheric Pressure using van der Waals Broadening

    SciTech Connect

    Munoz, Jose; Yubero, Cristina; Calzada, Maria Dolores [Grupo de Espectroscopia de Plasmas, Edificio A. Einstein (C-2), Campus Rabanales, Universidad de Cordoba (Spain); Dimitrijevic, Milan S. [Astronomical Observatory, Volgina 7, 11060 Belgrade (Serbia)

    2008-10-22

    The use of the van der Waals broadening of Ar atomic lines to determine the gas temperature in Ar-He plasmas, taking into account both argon and helium atoms as perturbers, has been analyzed. The values of the gas temperature inferred from this broadening have been compared with those obtained from the spectra of the OH molecular species in the discharge.

  4. Modelling of an inductively coupled plasma torch with argon at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Bahouh, Hanene; Rebiai, Saida; Rochette, David; Vacher, Damien; Dudeck, Michel

    2014-05-01

    A fluid dynamic model is used to simulate the electromagnetic field, fluid flow and heat transfer in an inductively coupled plasma torch working at atmospheric pressure for argon plasma. The numerical simulation is carried out by using the finite element method based on COMSOL software. The two-dimensional profiles of the electric field, temperature, velocity and charged particle densities are demonstrated inside the discharge region. These numerical results are obtained for a fixed flow rate, frequency and electric power.

  5. Activation of the fibrinolytic, coagulation and plasma kallikrein-kinin systems during and after open heart surgery in children.

    PubMed

    Saatvedt, K; Lindberg, H; Michelsen, S; Pedersen, T; Geiran, O R

    1995-07-01

    Activation of the fibrinolytic, coagulation and plasma kallikrein-kinin systems may be responsible for some of the coagulation disorders and inflammatory sequelae seen after extracorporeal circulation. The activation pattern of these systems was studied in 10 children undergoing open heart surgery with extracorporeal circulation. Blood samples were drawn serially before, during and up to 48 h after surgery. The heparin injection induced a significant elevation of plasmin (PL) (p < 0.05) which stayed elevated during extracorporeal circulation. Antiplasmin (AP) values were reduced at wound closure, while the levels were significantly elevated 48 h postoperatively (p < 0.05). alpha 2-antiplasmin-plasmin (APP) increased significantly perioperatively peaking 10 min after the initiation of cardiopulmonary bypass (p < 0.05). The coagulation markers thrombin-antithrombin (TAT) and the prothrombin fragment F1 & 2 increased significantly, peaking at wound closure and at termination of bypass respectively (p < 0.05). Plasma kallikrein (KK) values increased significantly with subsequent decreased levels of prekallikrein (PKK) and kallikrein inhibitor (KKI) after heparin injection. The KK level stayed elevated during cardiopulmonary bypass (CPB). The proenzyme functional inhibition index (PFI index), defined as the sum of deviations from the control values for proenzyme and functional inhibition values of the coagulation, fibrinolytic and plasma kallikrein-kinin systems, correlated significantly to the duration of cardiopulmonary bypass (p < 0.05). We conclude that open heart surgery in children activates the fibrinolytic, coagulation and plasma kallikrein-kinin systems. PMID:7569739

  6. Compact cryogenic source of periodic hydrogen and argon droplet beams for relativistic laser-plasma generation

    SciTech Connect

    Fraga, R. A. Costa; Kalinin, A.; Kuehnel, M.; Schottelius, A. [Institut fuer Kernphysik, J. W. Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Hochhaus, D. C.; Neumayer, P. [EMMI Extreme Matter Institute and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); FIAS Frankfurt Institute for Advanced Studies, J. W. Goethe-Universitaet, Ruth-Moufang-Str. 1, 60438 Frankfurt am Main (Germany); Polz, J. [Institut fuer Optik und Quantenelektronik, Max-Wien-Platz 1, 07743 Jena (Germany); Kaluza, M. C. [Institut fuer Optik und Quantenelektronik, Max-Wien-Platz 1, 07743 Jena (Germany); Helmholtz-Institut Jena, Froebelstieg 3, 07743 Jena (Germany); Grisenti, R. E. [Institut fuer Kernphysik, J. W. Goethe-Universitaet, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany)

    2012-02-15

    We present a cryogenic source of periodic streams of micrometer-sized hydrogen and argon droplets as ideal mass-limited target systems for fundamental intense laser-driven plasma applications. The highly compact design combined with a high temporal and spatial droplet stability makes our injector ideally suited for experiments using state-of-the-art high-power lasers in which a precise synchronization between the laser pulses and the droplets is mandatory. We show this by irradiating argon droplets with multi-terawatt pulses.

  7. Compact cryogenic source of periodic hydrogen and argon droplet beams for relativistic laser-plasma generation.

    PubMed

    Costa Fraga, R A; Kalinin, A; Kühnel, M; Hochhaus, D C; Schottelius, A; Polz, J; Kaluza, M C; Neumayer, P; Grisenti, R E

    2012-02-01

    We present a cryogenic source of periodic streams of micrometer-sized hydrogen and argon droplets as ideal mass-limited target systems for fundamental intense laser-driven plasma applications. The highly compact design combined with a high temporal and spatial droplet stability makes our injector ideally suited for experiments using state-of-the-art high-power lasers in which a precise synchronization between the laser pulses and the droplets is mandatory. We show this by irradiating argon droplets with multi-terawatt pulses. PMID:22380120

  8. Contamination d'un plasma d'argon par des vapeurs anodiques de cuivre P. Andanson et B. Cheminat

    E-print Network

    Boyer, Edmond

    775 Contamination d'un plasma d'argon par des vapeurs anodiques de cuivre P. Andanson et B proche de l'anode en cuivre (1 mm à 1 cm) d'un arc stabilisé sous atmosphère d'argon (15 A et 30 A) est arc discharge in argon (15 A and 30 A) is studied. An important drop in temperature due to the metal

  9. An argon-nitrogen-hydrogen mixed-gas plasma as a robust ionization source for inductively coupled plasma mass spectrometry

    NASA Astrophysics Data System (ADS)

    Makonnen, Yoseif; Beauchemin, Diane

    2014-09-01

    Multivariate optimization of an argon-nitrogen-hydrogen mixed-gas plasma for minimum matrix effects, while maintaining analyte sensitivity as much as possible, was carried out in inductively coupled plasma mass spectrometry. In the presence of 0.1 M Na, the 33.9 ± 3.9% (n = 13 elements) analyte signal suppression on average observed in an all-argon plasma was alleviated with the optimized mixed-gas plasma, the average being - 4.0 ± 8.8%, with enhancement in several cases. An addition of 2.3% v/v N2 in the outer plasma gas, and 0.50% v/v H2 to the central channel, as a sheath around the nebulizer gas flow, was sufficient for this drastic increase in robustness. It also reduced the background from ArO+ and Ar2+ as well as oxide levels by over an order of magnitude. On the other hand, the background from NO+ and ArN+ increased by up to an order of magnitude while the levels of doubly-charged ions increased to 7% (versus 2.7% in an argon plasma optimized for sensitivity). Furthermore, detection limits were generally degraded by 5 to 15 fold when using the mixed-gas plasma versus the argon plasma for matrix-free solution (although they were better for several elements in 0.1 M Na). Nonetheless, the drastically increased robustness allowed the direct quantitative multielement analysis of certified ore reference materials, as well as the determination of Mo and Cd in seawater, without using any matrix-matching or internal standardization.

  10. Influence of oxygen in atmospheric-pressure argon plasma jet on sterilization of Bacillus atrophaeous spores

    SciTech Connect

    Lim, Jin-Pyo; Uhm, Han S.; Li, Shou-Zhe [Department of Molecular Science and Technology, Ajou University, San 5 Wonchon-Dong, Youngtong-Gu, Suwon 443-749 (Korea, Republic of); State Key Laboratory of Materials Modification by Laser, Ion and Electron Beams Department of Physics, Dalian University of Technology, Dalian 116024 (China)

    2007-09-15

    A nonequilibrium Ar/O{sub 2} plasma discharge at atmospheric pressure was carried out in a coaxial cylindrical reactor with a stepped electrode configuration powered by a 13.56 MHz rf power supplier. The argon glow discharge with high electron density produces oxygen reactive species in large quantities. Argon plasma jets penetrate deep into ambient air and create a path for oxygen radicals to sterilize microbes. A sterilization experiment with bacterial endospores indicates that an argon-oxygen plasma jet very effectively kills endospores of Bacillus atrophaeus (ATCC 9372), thereby demonstrating its capability to clean surfaces and its usefulness for reinstating contaminated equipment as free from toxic biological warfare agents. The decimal reduction time (D values) of the Ar/O{sub 2} plasma jet at an exposure distance of 0.5-1.5 cm ranges from 5 to 57 s. An actinometric comparison of the sterilization data shows that atomic oxygen radicals play a significant role in plasma sterilization. When observed under a scanning electron microscope, the average size of the spores appears to be greatly reduced due to chemical reactions with the oxygen radicals.

  11. Acute gastric necrosis after routine oesophagogastroduodenoscopy with therapeutic argon plasma coagulation.

    PubMed

    Sahnan, K; Davis, B J H; Bagenal, J; Cullen, S; Appleton, S

    2013-09-01

    A 56-year-old woman presented to the accident and emergency department with peritonitis 2 days after a routine oesophagogastroduodenoscopy. She was taken to theatre with the finding of gastric necrosis. Blood and peritoneal cultures grew group A haemolytic Streptococcus. Histology revealed normal vasculature, no volvulus but marked neutrophilia in the submucosa with an intact mucosa. The stomach was resected and the patient recovered in the intensive care unit but overwhelming acidosis progressed to multiorgan failure and treatment was eventually withdrawn. Acute phlegmonous gastritis has been well described in the literature but mainly before the advent of antibiotics. The most common organism is group A haemolytic Streptococcus (commonly found in throat infections) and predisposing factors include instrumentation. Should antibiotics be given at the start of an oesophagogastroduodenoscopy and should routine procedures be delayed if active upper respiratory tract infections are present? PMID:24025279

  12. Modeling of ionization composition in argon plasma with fast electrons

    Microsoft Academic Search

    V. S. Zakharov; V. G. Novikov

    2009-01-01

    Discharge and laser produced plasmas often have non-equilibrium electron distributions containing fast electrons that may\\u000a have a profound effect on the ionization balance. The influence of high energy electrons on the ionization balance in the\\u000a collisional-radiative equilibrium model for optically thin plasma is considered forthwith. A nonmaxwellian electron distribution\\u000a with fast electrons at energies and concentrations is used for calculating

  13. Surface modification of ultra-high molecular weight polyethylene (UHMWPE) by argon plasma

    NASA Astrophysics Data System (ADS)

    Liu, Hengjun; Pei, Yanan; Xie, Dong; Deng, Xingrui; Leng, Y. X.; Jin, Yong; Huang, Nan

    2010-04-01

    In this work, argon (Ar) plasma generated by microwave electron cyclotron resonance (MWECR) has been used to modify the UHMWPE in order to increase the wear resistance. The results showed that the wettability, anti-scratch and wear resistance of UHMWPE treated by the Ar plasma had been improved, comparing with native UHMWPE. The FTIR and XPS spectra indicated the improvement of wettability should come from the oxygen based functional groups generated on the surface of UHMWPE. The improvement of anti-scratch and wear resistance may come from the enhancement of crosslinking of UHMWPE by Ar plasma treatment.

  14. Influence of dissociative recombination on the LTE of argon high-frequency plasmas at atmospheric pressure

    Microsoft Academic Search

    Abel Sainz; Joelle Margot; Maria Carmen Garcia; Maria Dolores Calzada

    2004-01-01

    This work presents a few preliminary results from a collisional-radiative\\u000a(CR) model intended to describe an argon microwave (2.45 GHz) plasma at\\u000aatmospheric pressure. This model aims to investigate the influence of\\u000adissociative recombination products on the Saha-Boltzmann plasma equilibrium.\\u000aThe model is tested through comparison with experimental results obtained in an\\u000aargon plasma column generated by a traveling electromagnetic

  15. Oral Bacterial Deactivation Using a Low-Temperature Atmospheric Argon Plasma Brush

    PubMed Central

    Yang, Bo; Chen, Jierong; Yu, Qingsong; Li, Hao; Lin, Mengshi; Mustapha, Azlin; Hong, Liang; Wang, Yong

    2010-01-01

    Summary Objectives To study the plasma treatment effects on deactivation effectiveness of oral bacteria. Methods A low temperature atmospheric argon plasma brush were used to study the oral bacterial deactivation effects in terms of plasma conditions, plasma exposure time, and bacterial supporting media. Oral bacteria of Streptococcus mutans and Lactobacillus acidophilus with an initial bacterial population density between 1.0 × 108 and 5.0 × 108 cfu/ml were seeded on various media and their survivability with plasma exposure was examined. Scanning electron microscopy was used to examine the morphological changes of the plasma treated bacteria. Optical absorption was used to determine the leakage of intracellular proteins and DNAs of the plasma treated bacteria. Results The experimental data indicated that the argon atmospheric plasma brush was very effective in deactivating oral bacteria. The plasma exposure time for a 99.9999% cell reduction was less than 15 seconds for S. mutans and within 5 minutes for L. acidophilus. It was found that the plasma deactivation efficiency was also dependent on the bacterial supporting media. With plasma exposure, significant damages to bacterial cell structures were observed with both bacterium species. Leakage of intracellular proteins and DNAs after plasma exposure was observed through monitoring the absorbance peaks at wavelengths of 280nm and 260nm, respectively. Conclusion The experimental results from this study indicated that low temperature atmospheric plasma treatment was very effective in deactivation of oral bacteria and could be a promising technique in various dental clinical applications such as bacterial disinfection and caries early prevention, etc. PMID:20951184

  16. Interpretation of the optical emission of argon in the plume of the Advanced Plasma Source

    NASA Astrophysics Data System (ADS)

    Harhausen, J.; Loffhagen, D.; Foest, R.

    2015-02-01

    The plume of the argon plasma of the Advanced Plasma Source employed for the deposition of optical coatings has been investigated by means of optical emission spectroscopy, Langmuir probe measurements as well as collisional radiative modeling using the measured electron energy probability function as the input. The emission of the ten argon lines considered is found to exhibit a cone-shaped spatial distribution. The emission on the axis of symmetry decreases exponentially with increasing distance from the source in good agreement with the results obtained by collisional radiative modeling and the radial extension of the Gaussian profile in the radial direction increases linearly along the axial direction. The analysis of the measured electron properties shows in particular that the electron pressure varies between about 2 Pa near the plasma source exit and 1 mPa at larger distances. The argon neutral density determined by collisional radiative modeling is found to be about 6 · 1011 cm?3 in the plasma plume in front of the source exit corresponding to a degree of ionization as high as 60%.

  17. Experimental Investigation of Laser-sustained Plasma in Supersonic Argon Flow

    NASA Astrophysics Data System (ADS)

    Sperber, David; Eckel, Hans-Albert; Moessinger, Peter; Fasoulas, Stefanos

    2011-11-01

    Laser-induced energy deposition is widely discussed as a flow control technique in supersonic transportation. In case of thermal laser-plasma upstream of a blunt body, a substantial adaptation of shock wave geometry and magnitude of wave drag is predicted. Related to the research on laser supported detonation, the paper describes the implementation of laser-sustained plasma in a supersonic Argon jet. The stable plasma state is generated by the intersection of a Q-switched Nd:YAG-laser and a continuous wave CO2-laser beams, for ignition and maintenance of the plasma respectively. A miniature supersonic Ludwieg tube test facility generates a supersonic jet at velocities of Mach 2.1. Modifications of the flow and plasma conditions are investigated and characterized by Schlieren flow visualisation, laser energy transmission and plasma radiation measurements. The results include the discussions of the flow field as well as the required laser and gas parameters.

  18. XPS Study of Plasma- and Argon Ion-Sputtered Polytetrafluoroethylene

    NASA Technical Reports Server (NTRS)

    Golub, Morton A.; Kliss, Mark (Technical Monitor)

    1997-01-01

    The similarity of plasma-polymerized tetrafluoroethylene (PPTFE) and the fluoropolymer film deposited by rf (radio frequency) plasma sputtering (SPTFE) of polytetrafluoroethylene (PTFE), noted earlier in the literature, has been reconfirmed. FT-IR (Fourier Transform Infrared), XPS (X ray Photoelectron Spectroscopy) and UV (ultraviolet) spectroscopy has been employed in apparently the first study to involve preparation of PPTFE and SPTFE in the same reactor and under comparable low-power plasma conditions. Most of the work concerned the use of He or Ar as sputtering gas, but some runs were also carried out with the other rare gases Ne, Kr and Xe. The C1s XPS spectra of SPTFE films displayed a relatively higher content of CF2 groups, and yielded higher F/C (fluorine / carbon) ratios, than PPTFE films, while the SPTFE films were somewhat more transparent in the UV than PPTFE. The F/C ratios for SPTFE were essentially independent of the rare gas used for sputtering. Increasing rf power from 10 to 50 W for Xe plasma-sputtering of PTFE resulted in successively lower F/C ratios (1.55 to 1.21), accompanied by sputtering of the glass reactor occurring at 40 W and above. Some limited XPS, FT-IR and UV data are presented on Ar ion-sputtered PTFE.

  19. Soft X-ray spectroscopic study of a gas-puff Z-pinch argon plasma

    Microsoft Academic Search

    Seong Ho Kim; Dong-Eon Kim; Tong Nyong Lee

    1998-01-01

    X-ray radiation characteristics of argon plasma produced by a gas-puff Z-pinch device were investigated using an X-ray crystal spectrometer, an X-ray diode, and an extreme ultraviolet (XUV) spectrometer. Using a germanium crystal we have observed spectral emission from Ar XVII produced by hot spots at the pinched stage. With the help of a 2-m grazing incidence XUV spectrometer, the spectrum

  20. Atom-atom inelastic collisions and three-body atomic recombination in weakly ionized argon plasmas

    NASA Technical Reports Server (NTRS)

    Braun, C. G.; Kunc, J. A.

    1989-01-01

    A stationary collisional-radiative model including both inelastic electron-atom and atom-atom collisions is used to examine nonequilibrium weakly ionized argon plasmas with atomic densities 10 to the 16th to 10 to the 20th/cu cm, temperatures below 6000 K, and with different degrees of radiation trapping. It is shown that three-body atomic recombination becomes important at high particle densities. Comparison is made between the present approach and Thomson's theory for atomic recombination.

  1. “Hot electrons” influence on argon K-spectrum emitted from Plasma Focus discharges

    Microsoft Academic Search

    L. Karpinski; M. Paduch; M. Scholz; K. Tomaszewski; A. Szydlowski; S. Pikuz; V. Romanova; A. Ya. Faenov; J. Abdallah; R. E. H. Clark

    2000-01-01

    New results of spectroscopical investigation of Plasma Focus discharges performed on the PF-1000 facility (IPPiLM, Warsaw)\\u000a are presented. Two-dimensional space resolved K-sheel spectra of argon were registered using a mica crystal spectrometer of\\u000a FSSR-2D type. The important role of the electron beam in forming of these spectra is shown. A modeling of the spectra by the\\u000a collisional-radiative theory with inclusion

  2. Comparison of atmospheric-pressure helium and argon plasmas generated by capacitively coupled radio-frequency discharge

    NASA Astrophysics Data System (ADS)

    Li, Shou-Zhe; Lim, Jin-Pyo; Kang, Jung G.; Uhm, Han S.

    2006-09-01

    In this paper, the electrical discharge characteristics of plasmas generated in coaxial cylindrical electrodes capacitively powered by a radio-frequency power supply at atmospheric pressure are investigated with respect to helium and argon gases. The electrical discharge parameters, voltage (V), current (I), and power (P), are measured for both helium and argon plasmas, and the electron temperatures and electron densities for them are evaluated by means of the equivalent circuit model and the power balance equation. By comparison of the discharge characteristics of the helium and argon plasmas, it is found that the discrepant macroscopic characteristics of helium and argon plasma, viz., current and voltage characteristics and current and power characteristics, are owed to their own intrinsic microscopic parameters of the helium and argon atoms, such as the first excited energy, the ionization energy, the total cross section, and the atom mass. Furthermore, the influences of the additive gas, oxygen gas, on the electrical discharge characteristics are also investigated in the helium and argon plasmas, which are closely related to the electron temperature of plasmas.

  3. Activation of plasma coagulation by retransfusion of unwashed drainage blood after hip joint arthroplasty: a prospective study.

    PubMed

    Duchow, J; Ames, M; Hess, T; Seyfert, U

    2001-10-01

    Twelve patients undergoing cementless hip joint arthroplasty were retransfused with unwashed drainage blood collected postoperatively. Global coagulation parameters, coagulation factors (factor V:C, factor VIII:C, activated factor XII, and factor XIII) and markers of thrombin generation (F1+2 Fibrin split products, thrombin-antithrombin complexes), fibrin generation (fibrinogen and fibrin degradation products), and fibrinolysis (D-dimers, thrombin degradation products, plasminogen) were determined. High levels of factor XIIa, thrombin and fibrin generation markers, and markers of fibrinolysis were present in the shed blood. After retransfusion (mean, 433 mL), increased levels of these markers together with decreased values for factor XIII and plasminogen were indicative of renewed clot formation and fibrinolysis in the circulation. These changes were highly significant compared with preretransfusion values. The unwashed drainage blood contained high levels of procoagulation material and induced an activation of the plasma coagulation pathway with renewed clot formation and fibrinolysis in the patients. PMID:11607899

  4. Kinetic simulations of argon dusty plasma afterglow including metastable atom kinetics

    SciTech Connect

    Alexandrov, A. L., E-mail: a_alex@itam.nsc.ru; Schweigert, I. V.; Ariskin, D. A. [Siberian Branch of the Russian Academy of Sciences, Institute of Theoretical and Applied Mechanics (Russian Federation)

    2013-04-15

    The afterglow of a dusty plasma of rf discharge in argon is simulated by the particle-in-cell-Monte Carlo collision (PIC-MCC) method. The experimental observation that heavy dust contamination of plasma leads to an anomalous increase in the electron density at the beginning of afterglow is explained by release of electrons from the dust surface. Under the assumption that the floating potential of particles is in equilibrium with plasma conditions, the fast cooling of electrons in afterglow plasma due to a rapid escape of hot electrons from the volume leads to a decrease in the magnitude of the floating potential and hence to a loss of charge by dust. The intensive desorption of electrons from nanoparticles is the origin of anomalous behavior of the electron density. At the next stage of afterglow, when the electrons become cool, the plasma decay is defined by ambipolar diffusion. The effect of metastable argon atoms is also considered. Additional ionization due to metastable atom collisions affects the electron temperature but does not change the behavior of the electron density qualitatively.

  5. Kinetic simulations of argon dusty plasma afterglow including metastable atom kinetics

    NASA Astrophysics Data System (ADS)

    Alexandrov, A. L.; Schweigert, I. V.; Ariskin, D. A.

    2013-04-01

    The afterglow of a dusty plasma of rf discharge in argon is simulated by the particle-in-cell-Monte Carlo collision (PIC-MCC) method. The experimental observation that heavy dust contamination of plasma leads to an anomalous increase in the electron density at the beginning of afterglow is explained by release of electrons from the dust surface. Under the assumption that the floating potential of particles is in equilibrium with plasma conditions, the fast cooling of electrons in afterglow plasma due to a rapid escape of hot electrons from the volume leads to a decrease in the magnitude of the floating potential and hence to a loss of charge by dust. The intensive desorption of electrons from nanoparticles is the origin of anomalous behavior of the electron density. At the next stage of afterglow, when the electrons become cool, the plasma decay is defined by ambipolar diffusion. The effect of metastable argon atoms is also considered. Additional ionization due to metastable atom collisions affects the electron temperature but does not change the behavior of the electron density qualitatively.

  6. Characteristics of argon plasma waveguide produced by alumina capillary discharge for short wavelength laser application

    SciTech Connect

    Higashiguchi, Takeshi; Yugami, Noboru [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Bobrova, Nadezhda; Sasorov, Pavel [Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya Str. 25, 117218 Moscow (Russian Federation); Sakai, Shohei [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Sentoku, Yasuhiko [Department of Physics, University of Nevada, Mail Stop 220, Reno, Nevada 89506 (United States); Kodama, Ryosuke [Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Graduate School of Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2012-05-01

    We have reported the argon (Ar) plasma waveguide produced in an alumina (Al{sub 2}O{sub 3}) capillary discharge and used to guide ultrashort laser pulses at intensities of the order of 10{sup 16} W/cm{sup 2}. The electron density in the plasma waveguide was measured to be 1x10{sup 18} cm{sup -3}, in agreement with one-dimensional magnetrohydrodynamic (MHD) simulations. The MHD code was also used to evaluate the degree of ionization of argon (Ar) in the preformed plasma waveguide. The maximum ion charge state of Ar{sup 3+} in capillary discharge was measured and obtained in the MHD simulations. The spectrum of the propagated laser pulse in the Ar plasma waveguide was not modified and was well reproduced by a particle-in-cell simulations under initial ion charge state of Ar{sup 3+} in the preformed plasma waveguide. The optimum timing for the laser pulse injection was around 150 ns after initiation of a discharge with a peak current of 200 A.

  7. Comparison of temperature and composition measurement by spectroscopic methods for argon-helium arc plasma

    NASA Astrophysics Data System (ADS)

    Xiao, Xiao; Hua, Xueming; Wu, Yixiong

    2015-03-01

    Three different spectroscopic methods were used to calculate the temperature and composition distribution of argon-helium arc plasma-the Fowler-Milne method, the two-line intensity correlation method and the Boltzmann plot method. Experimental errors, including random errors and systematic errors, were analyzed in detail to comparing the accuracy of different methods. Due to the large differences of physical characteristics between argon and helium, there were limited reports on the measurement of temperature and composition distribution in argon-helium arc plasma. To this end, The Fowler-Milne method and the Boltzmann plot method were modified in this paper. Three spectroscopic methods were compared with other's simulation result and showed good agreement with each other, except the Boltzmann plot method which had partly distinction. Through comparison and analysis of error bar in those methods, it was found that both the Fowler-Milne method and the two-line intensity correlation method had less error than the Boltzmann plot method, while the Fowler-Milne method, which is irrelevant to atomic transition probabilities and experimental apparatus calibration, had the minimum error.

  8. Influence of centrifuge brake on residual platelet count and routine coagulation tests in citrated plasma.

    PubMed

    Daves, Massimo; Giacomuzzi, Katia; Tagnin, Enrico; Jani, Erika; Adcock Funk, Dorothy M; Favaloro, Emmanuel J; Lippi, Giuseppe

    2014-04-01

    Sample centrifugation is an essential step in the coagulation laboratory, as clotting tests are typically performed on citrated platelet (PLT) poor plasma (PPP). Nevertheless, no clear indication has been provided as to whether centrifugation of specimens should be performed with the centrifuge brake set to on or off. Fifty consecutive sodium citrate anticoagulated samples were collected and divided into two aliquots. The former was centrifuged as for Clinical Laboratory Standards Institute (CLSI) guidelines with the centrifuge brake set to on, whereas the latter was centrifuged again as for CLSI guidelines, but with the brake set to off. In the PPP of all samples, a PLT count was performed, followed by the analysis of activated partial thromboplastin time (APTT), prothrombin time (PT) and fibrinogen (FBG). The PLT count after samples centrifugation was substantially reduced, either with centrifuge brake set to on or off (5?±?1 versus 3?±?1?×?10/l; P?=?0.009). The frequency of samples exceeding a PLT count less than 10?×?10/l was nearly double in samples centrifuged with the brake on than in those with the brake off (14 versus 8%; P?coagulation testing should be preferably performed with the centrifuge brake set to off for providing a better quality specimen. PMID:24389587

  9. Angular Distribution of Argon Ions and X-Ray Emissions in the Apf Plasma Focus Device

    NASA Astrophysics Data System (ADS)

    Etaati, G. R.; Amrollahi, R.; Habibi, M.; Baghdadi, R.

    2011-04-01

    Angular distribution of ion beam emission from an argon gas-filled plasma focus devices has been investigated using an array of five Faraday cups. The argon ion beam emission is found to be highly pressure-dependent and reaches its maximum at the pressure of 1 torr. The ions flux decreased as the working pressure increased; the maximum ion density at 1 torr was estimated to be around 9.24 × 1024 ions/steradian. Also, the study on the angular distribution of X-rays has been carried out using TLD-100 dosimeters. The intensity of ions reduced significantly at angles higher than ±11° but the X-ray distribution was bimodal, peaked approximately at ±15°.

  10. A method for evaluations on the radiation trapping in an inductively coupled plasma in argon

    NASA Astrophysics Data System (ADS)

    Scharwitz, Christian; Makabe, Toshiaki

    2009-12-01

    One of the general challenges for the evaluation and interpretation of optical emission spectroscopy measurements is the occurrence of radiation trapping, which is also named self-absorption or opacity. A convenient technique to treat radiation trapping is the introduction of a parameter, which is called escape factor and gives a measure for the amount of radiation trapping. In this paper evaluations on the concept of escape factors are presented for an inductively coupled plasma in argon. Especially, the strong argon line at 811.53 nm, which arises from the transition of 2p9-1s5, is under consideration. To estimate escape factors for this line, a particular method is proposed and presented here. First experimental results are obtained under the restrictive assumptions that transitions into the resonant levels 1s2 and 1s4 are sufficiently optically thin and ratios of population densities are constant.

  11. A method for evaluations on the radiation trapping in an inductively coupled plasma in argon

    SciTech Connect

    Scharwitz, Christian; Makabe, Toshiaki [Department of Electronics and Electrical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama, 223-8522 (Japan)

    2009-12-01

    One of the general challenges for the evaluation and interpretation of optical emission spectroscopy measurements is the occurrence of radiation trapping, which is also named self-absorption or opacity. A convenient technique to treat radiation trapping is the introduction of a parameter, which is called escape factor and gives a measure for the amount of radiation trapping. In this paper evaluations on the concept of escape factors are presented for an inductively coupled plasma in argon. Especially, the strong argon line at 811.53 nm, which arises from the transition of 2p{sub 9}-1s{sub 5}, is under consideration. To estimate escape factors for this line, a particular method is proposed and presented here. First experimental results are obtained under the restrictive assumptions that transitions into the resonant levels 1s{sub 2} and 1s{sub 4} are sufficiently optically thin and ratios of population densities are constant.

  12. Theoretical study of nanoparticle formation in thermal plasma processing: Nucleation, coagulation and aggregation

    NASA Astrophysics Data System (ADS)

    Mendoza Gonzalez, Norma Yadira

    This work presents a mathematical modeling study of the synthesis of nanoparticles in radio frequency (RF) inductively coupled plasma (ICP) reactors. The purpose is to further investigate the influence of process parameters on the final size and morphology of produced particles. The proposed model involves the calculation of flow and temperature fields of the plasma gas. Evaporation of raw particles is also accounted with the particle trajectory and temperature history calculated with a Lagrangian approach. The nanoparticle formation is considered by homogeneous nucleation and the growth is caused by condensation and Brownian coagulation. The growth of fractal aggregates is considered by introducing a power law exponent Df. Transport of nanoparticles occurs by convection, thermophoresis and Brownian diffusion. The method of moments is used to solve the particle dynamics equation. The model is validated using experimental results from plasma reactors at laboratory scale. The results are presented in the following manner. First, use is made of the computational fluid dynamics software (CFD), Fluent 6.1 with a commercial companion package specifically developped for aerosols named: Fine Particle Model (FPM). This package is used to study the relationship between the operating parameters effect and the properties of the end products at the laboratory scale. Secondly, a coupled hybrid model for the synthesis of spherical particles and fractal aggregates is developped in place of the FPM package. Results obtained from this model will allow to identify the importance of each parameter in defining the morphology of spherical primary particles and fractal aggregates of nanoparticles. The solution of the model was made using the geometries and operating conditions of existing reactors at the Centre de Recherche en Energie, Plasma et Electrochimie (CREPE) of the Universite de Sherbrooke, for which experimental results were obtained experimentally. Additionally, this study demonstrates the importance of the flow and temperature fields on the growth of fractal particles; namely the aggregates.

  13. Comparison of the effects of CORM-2, CORM-3 and CORM-A1 on coagulation in human plasma.

    PubMed

    Nielsen, Vance G; Garza, Joshua I

    2014-12-01

    Carbon monoxide derived from the catalytic action of heme oxygenase-1 or carbon monoxide-releasing molecules (CORMs) has been found to potentially be an anticoagulant or procoagulant agent. Of interest, two water-soluble CORMs, CORM-3 and CORM-A1, recently became commercially available. Thus, the purpose of the present study was to assess and compare the effects of the previously well studied CORM-2 to the effects of CORM-3 and CORM-A1 on coagulation in citrated human plasma with thrombelastography. Plasma exposed to CORMs was incubated at 37°C for at least one carbon monoxide release half-time, and then tissue factor-activated coagulation was commenced with calcium addition. CORM-2 and CORM-3 enhanced the velocity of clot formation and thrombus strength in a similar manner, whereas CORM-A1 did not affect coagulation. However, CORM-A1 did diminish tissue-type plasminogen activator initiated fibrinolysis. The similarity in effect on coagulation by CORM-2 and CORM-3 was likely secondary to the relatively inert effect of their ruthenium-containing carrier molecule, whereas the boron-containing CORM-A1 may have had no effect secondary to boron binding to fibrinogen, preventing carbon monoxide-mediated changes in fibrinogen protein structure via attached heme group(s). Future investigations with CORMs should have special attention to confounding effects of the carrier molecule. PMID:25058038

  14. Optical diagnostics of a low power---low gas flow rates atmospheric-pressure argon plasma created by a microwave plasma torch

    Microsoft Academic Search

    Chuji Wang; Nimisha Srivastava; Susan Scherrer; Ping-Rey Jang; Theodore S. Dibble; Yixiang Duan

    2009-01-01

    We employ a suite of optical techniques, namely, visual imaging, optical emission spectroscopy and cavity ringdown spectroscopy (CRDS), to characterize a low power, low gas flow rates, atmospheric-pressure argon microwave induced plasma. The plasma is created by a microwave plasma torch, which is excited by a 2.45 GHz microwave with powers ranging from 60 to 120 W. A series of

  15. Mass spectrometric characterization of N- and O-glycans of plasma-derived coagulation factor VII.

    PubMed

    Fenaille, François; Groseil, Catherine; Ramon, Christine; Riandé, Sandrine; Siret, Laurent; Chtourou, Sami; Bihoreau, Nicolas

    2008-12-01

    Factor VII (FVII) is a vitamin K-dependent glycoprotein which, in its activated form (FVIIa), participates in the coagulation process by activating factor X and factor IX. FVII is secreted as single peptide chain of 406 residues. Plasma-derived FVII undergoes many post-translational modifications such as gamma-carboxylation, N- and O-glycosylation, beta-hydroxylation. Despite glycosylation of recombinant FVIIa has been fully characterized, nothing is reported on the N- and O-glycans of plasma-derived FVII (pd-FVII) and on their structural heterogeneity at each glycosylation site. N- and O-glycosylation sites and site specific heterogeneity of pd-FVII were studied by various complementary qualitative and quantitative techniques. A MALDI-MS analysis of the native protein indicated that FVII is a 50.1 kDa glycoprotein modified on two sites by diantennary, disialylated non-fucosylated (A2S2) glycans. LC-ESIMS/MS analysis revealed that both light chain and heavy chain were N-glycosylated mainly by A2S2 but also by triantennary sialylated glycans. Nevertheless, lower amounts of triantennary structures were found on Asn(322) compared to Asn(145). Moreover, the triantennary glycans were shown to be fucosylated. In parallel, quantitative analysis of the isolated glycans by capillary electrophoresis indicated that the diantennary structures represented about 50% of the total glycan content. Glycan sequencing using different glycanases led to the identification of triantennary difucosylated structures. Last, MS and MS/MS analysis revealed that FVII is O-glycosylated on the light chain at position Ser(60) and Ser(52) which are modified by oligosaccharide structures such as fucose and Glc(Xyl)(0-1-2), respectively. These latter three O-glycans coexist in equal amounts in plasma-derived FVII. PMID:18642129

  16. The role of visible and resonance radiation in the energy balance of LTE plasma in argon

    NASA Astrophysics Data System (ADS)

    Golubovskii, Yu B.; Maiorov, V. A.; Gorchakov, S.; Uhrlandt, D.

    2015-02-01

    Energy losses due to radiation in an LTE arc plasma in argon are investigated in the temperature range from 5000 to 15?000 K. Calculations of the radiation transport require us to know the absorption spectra; for that purpose, free–free, bound–free and bound–bound transitions are taken into account. The energy losses due to resonance transitions with large absorption coefficients are analyzed. The transport of visible radiation with small absorption coefficients is calculated by accurate integration over a whole spectrum. The resonance radiation transport in LTE plasma is described by the Biberman–Holstein equation, which is usually used in non-equilibrium plasma. As the temperature grows, radiation processes become the main channel of energy losses. It is shown that, despite the resonance radiation being trapped, the energy losses due to resonance radiation escape can achieve 10% of the total radiation losses.

  17. CARACTRISTIQUES D'UN PLASMA D'ARGON FORTEMENT IONIS DANS UNE DCHARGE PULSE A BASSE PRESSION

    E-print Network

    Paris-Sud XI, Université de

    659 CARACT�RISTIQUES D'UN PLASMA D'ARGON FORTEMENT IONIS� DANS UNE D�CHARGE PULS�E A BASSE PRESSION J. JOLLY Laboratoire de Physique des Plasmas (*), Université Paris XI, Bâtiment 212, 91405 Orsay of the discharge parameters : current density, filling pressure and tube radius. This model is applicable to pulsed

  18. Improved measurement of the electron temperature of a low density shock-heated argon plasma by means of microwaves

    Microsoft Academic Search

    C. P. Schneider

    1978-01-01

    Determining electron temperature in a low-density shock-heated argon plasma via microwave diagnostics is studied. A test section is developed permitting the simultaneous transmission of two microwave beams at different frequencies. Two corrections are applied to the measured attenuation of the transmitted waves in order to obtain the true attenuation due to wave power dissipation into the plasma, dependent on electron

  19. Argon–oxygen dc magnetron discharge plasma probed with ion acoustic waves

    SciTech Connect

    Saikia, Partha, E-mail: partha.008@gmail.com; Saikia, Bipul Kumar; Goswami, Kalyan Sindhu [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur, Kamrup, Assam 782 402 (India); Phukan, Arindam [Madhabdev College, Narayanpur, Lakhimpur, Assam 784164 (India)

    2014-05-15

    The precise determination of the relative concentration of negative ions is very important for the optimization of magnetron sputtering processes, especially for those undertaken in a multicomponent background produced by adding electronegative gases, such as oxygen, to the discharge. The temporal behavior of an ion acoustic wave excited from a stainless steel grid inside the plasma chamber is used to determine the relative negative ion concentration in the magnetron discharge plasma. The phase velocity of the ion acoustic wave in the presence of negative ions is found to be faster than in a pure argon plasma, and the phase velocity increases with the oxygen partial pressure. Optical emission spectroscopy further confirms the increase in the oxygen negative ion density, along with a decrease in the argon positive ion density under the same discharge conditions. The relative negative ion concentration values measured by ion acoustic waves are compared with those measured by a single Langmuir probe, and a similarity in the results obtained by both techniques is observed.

  20. Comparison of surface vacuum ultraviolet emissions with resonance level number densities. I. Argon plasmas

    SciTech Connect

    Boffard, John B., E-mail: jboffard@wisc.edu; Lin, Chun C. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Culver, Cody [Materials Science Program, University of Wisconsin, Madison, WI 53706 (United States); Wang, Shicong; Wendt, Amy E. [Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI 53706 (United States); Radovanov, Svetlana; Persing, Harold [Varian Semiconductor Equipment, Applied Materials Inc., Gloucester, MA 01939 (United States)

    2014-03-15

    Vacuum ultraviolet (VUV) photons emitted from excited atomic states are ubiquitous in material processing plasmas. The highly energetic photons can induce surface damage by driving surface reactions, disordering surface regions, and affecting bonds in the bulk material. In argon plasmas, the VUV emissions are due to the decay of the 1s{sub 4} and 1s{sub 2} principal resonance levels with emission wavelengths of 104.8 and 106.7?nm, respectively. The authors have measured the number densities of atoms in the two resonance levels using both white light optical absorption spectroscopy and radiation-trapping induced changes in the 3p{sup 5}4p?3p{sup 5}4s branching fractions measured via visible/near-infrared optical emission spectroscopy in an argon inductively coupled plasma as a function of both pressure and power. An emission model that takes into account radiation trapping was used to calculate the VUV emission rate. The model results were compared to experimental measurements made with a National Institute of Standards and Technology-calibrated VUV photodiode. The photodiode and model results are in generally good accord and reveal a strong dependence on the neutral gas temperature.

  1. Ozone-stimulated emission due to atomic oxygen population inversions in an argon microwave plasma torch

    SciTech Connect

    Lukina, N. A.; Sergeichev, K. F. [Russian Academy of Sciences, Prokhorov Institute of General Physics (Russian Federation)

    2008-06-15

    It is shown that, in a microwave torch discharge in an argon jet injected into an oxygen atmosphere at normal pressure, quasi-resonant energy transfer from metastable argon atoms to molecules of oxygen and ozone generated in the torch shell and, then, to oxygen atoms produced via the dissociation of molecular oxygen and ozone leads to the inverse population of metastable levels of atomic oxygen. As a result, the excited atomic oxygen with population inversions becomes a gain medium for lasing at wavelengths of 844.6 and 777.3 nm (the 3{sup 3}P-3{sup 3}S and 3{sup 5}P-3{sup 5}S transitions). It is shown that an increase in the ozone density is accompanied by an increase in both the lasing efficiency at these wavelength and the emission intensity of the plasma-forming argon at a wavelength of 811.15 nm (the {sup 2}P{sup 0}4s-{sup 2}P{sup 0}4p transition). When the torch operates unstably, the production of singlet oxygen suppresses ozone generation; as a result, the lasing effect at these wavelengths disappears.

  2. Waves generated in the vicinity of an argon plasma gun in the ionosphere

    NASA Technical Reports Server (NTRS)

    Cahill, L. J., Jr.; Arnoldy, R. L.; Lysak, R. L.; Peria, W.; Lynch, K. A.

    1993-01-01

    Wave and particle observations were made in the close vicinity of an argon plasma gun carned to over 600 km altitude on a sounding rocket. The gun was carned on a subpayload, separated from the main payload early in the flight. Twelve-second argon ion ejections were energized alternately with a peak energy of 100 or 200 eV. They produced waves, with multiple harmonics, in the range of ion cyclotron waves, 10 to 1000 Hz at rocket altitudes. Many of these waves could not be identified as corresponding to the cyclotron frequencies of any of the ions, argon or ambient, known to be present. In addition, the wave frequencies were observed to rise and fall and to change abruptly during a 12-s gun operation. The wave amplitudes, near a few hundred Hertz, were of the order of O. 1 V/m. Some of the waves may be ion-ion hybrid waves. Changes in ion populations were observed at the main payload and at the subpayload during gun operations. A gun-related, field-aligned, electron population also appeared.

  3. Solvent\\/detergent plasma for prevention of bleeding in recessively inherited coagulation disorders: dosing, pharmacokinetics and clinical efficacy

    Microsoft Academic Search

    Elena Santagostino; Maria Elisa Mancuso; Massimo Morfini; Mario Schiavoni; Annarita Tagliaferri; Giovanni Barillari; Pier Mannuccio Mannucci

    Design and Methods. In vivo recovery (IVR) of the deficient coagulation factor was deter- mined in a non-bleeding state in all patients and the mean values for FV, FVIII, FX, FXI and fibrinogen were 1.3, 1.2, 1.5, 1.3 and 1.5 dL\\/kg, respectively. The mean plasma half-life of FV, FVIII and FX was 18, 43 and 33 hours, respectively. All patients

  4. Effect of neutral gas heating in argon radio frequency inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Chin, O. H.; Jayapalan, K. K.; Wong, C. S.

    2014-08-01

    Heating of neutral gas in inductively coupled plasma (ICP) is known to result in neutral gas depletion. In this work, this effect is considered in the simulation of the magnetic field distribution of a 13.56 MHz planar coil ICP. Measured electron temperatures and densities at argon pressures of 0.03, 0.07 and 0.2 mbar were used in the simulation whilst neutral gas temperatures were heuristically fitted. The simulated results showed reasonable agreement with the measured magnetic field profile.

  5. Numerical simulations of a nonequilibrium argon plasma in a shock-tube experiment

    NASA Technical Reports Server (NTRS)

    Cambier, Jean-Luc

    1991-01-01

    A code developed for the numerical modeling of nonequilibrium radiative plasmas is applied to the simulation of the propagation of strong ionizing shock waves in argon gas. The simulations attempt to reproduce a series of shock-tube experiments which will be used to validate the numerical models and procedures. The ability to perform unsteady simulations makes it possible to observe some fluctuations in the shock propagation, coupled to the kinetic processes. A coupling mechanism by pressure waves, reminiscent of oscillation mechanisms observed in detonation waves, is described. The effect of upper atomic levels is also briefly discussed.

  6. Effects of storage time and temperature on coagulation tests and factors in fresh plasma

    PubMed Central

    Feng, Limin; Zhao, Ying; Zhao, Hongcan; Shao, Zhexin

    2014-01-01

    Coagulation tests and factors measurements have been widely applied in clinical practice. Pre-analytical conditions are very important in laboratory assessment.Here,we aim to determine the effects of storage time and temperature on activated partial thromboplastin time (APTT), fibrinogen (Fbg), prothrombin time (PT), the international normalized ratio (INR), thrombin time (TT), factor VIII activity (FVIII:C), and factor IX activity (FIX:C) in fresh plasma. Seventy-two blood samples were tested after storage for 0 (baseline), 2, 4, 6, 8, 12, and 24?h at 25°C (room temperature) and 4°C (refrigeration) in two centers. The mean percentage change of greater than 10% and the numbers of samples with greater than 10% percentage changes more than 25% were used to determine clinically relevant difference. We demonstrated that samples for Fbg, PT/INR, and TT could be safely stored for ?24?h; FVIII:C for ?2?h; FIX:C for ?4?h both at 4°C and 25°C; and APTT for ?12?h at 4°C and ?8?h at 25°C. PMID:24463857

  7. Effect of secondary emission on the argon plasma afterglow with large dust density

    NASA Astrophysics Data System (ADS)

    Denysenko, I. B.; Stefanovi?, I.; Azarenkov, N. A.; Burmaka, G. P.

    2015-02-01

    A zero-dimensional, space-averaged model for argon plasma afterglow with large dust density is developed. In the model, three groups of electrons in the plasma afterglow are assumed: (i) thermal electrons with Maxwellian distribution, (ii) energetic electrons generated by metastable-metastable collisions (metastable pooling), and (iii) secondary electrons generated at collisions of ions with the electrodes, which have sufficiently large negative voltages in the afterglow. The model calculates the time-dependencies for electron densities in plasma afterglow based on experimental decay times for metastable density and electrode bias. The effect of secondary emission on electron density in the afterglow is estimated by varying secondary emission yields. It is found that this effect is less important than metastable pooling. The case of dust-free plasma afterglow is considered also, and it is found that in the afterglow the effect of secondary emission may be more important than metastable pooling. The secondary emission may increase thermal electron density ne in dust-free and dusty plasma afterglows on a few ten percentages. The calculated time dependencies for ne in dust-free and dusty plasma afterglows describe well the experimental results.

  8. Reactor geometry and plasma uniformity in a planar inductively coupled radio frequency argon discharge

    NASA Astrophysics Data System (ADS)

    Stittsworth, J. A.; Wendt, A. E.

    1996-08-01

    The effects of chamber height on plasma uniformity are examined for a cylindrically symmetric planar inductive radio frequency (rf) (13.56 MHz) argon plasma generated with a single-turn circular loop antenna. Plasma uniformity is characterized by two-dimensional 0963-0252/5/3/011/img1 spatial profiles of plasma properties measured with a rf-filtered Langmuir probe. The results show a tendency for the radial location of the plasma density maximum to shift from the centre outward as the chamber height is decreased and pressure is increased. The location of the density maximum is insensitive to changes in discharge power. These observations are explained as a consequence of changes in axial and radial transport of ionizing energetic electrons as the reactor height L is varied. Because electron heating is localized at the radius of the maximum induced rf electric field 0963-0252/5/3/011/img2, the critical scale lengths are 0963-0252/5/3/011/img2 and L, in addition to the energy relaxation length for ionizing electrons 0963-0252/5/3/011/img4. The competition between axial and radial losses can lead, for 0963-0252/5/3/011/img5, to a sensitive dependence of plasma uniformity on discharge operating conditions.

  9. Enhanced specificity of immunoblotting using radiolabeled antigen overlay: studies of blood coagulation factor XII and prekallikrein in plasma

    SciTech Connect

    Laemmle, B.; Berrettini, M.; Griffin, J.H.

    1986-01-01

    Immunoblotting of blood coagulation Factor XII and plasma prekallikrein in whole plasma was performed using radiolabeled antigen for detection. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis of plasma and transfer to nitrocellulose sheets, the blots were first reacted with polyclonal goat anti-Factor XII or anti-prekallikrein antisera and then with /sup 125/I-Factor XII or /sup 125/I-prekallikrein, respectively. A major advantage of using radiolabeled antigen rather than radiolabeled secondary antibody was enhanced specificity of immunodetection of these antigens in plasma. This procedure was sensitive to approx.0.3 ng of either Factor XII or prekallikrein antigen and was useful for detection of Factor XII cleavage fragments in contact activated plasma. Radiolabeled antigen overlay may improve the specificity of immunoblotting of trace antigens in any complex mixtures.

  10. Stark broadening measurement of the electron density in an atmospheric pressure argon plasma jet with double-power electrodes

    SciTech Connect

    Qian Muyang; Ren Chunsheng; Wang Dezhen; Zhang Jialiang; Wei Guodong [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2010-03-15

    Characteristics of a double-power electrode dielectric barrier discharge of an argon plasma jet generated at the atmospheric pressure are investigated in this paper. Time-averaged optical emission spectroscopy is used to measure the plasma parameters, of which the excitation electron temperature is determined by the Boltzmann's plot method whereas the gas temperature is estimated using a fiber thermometer. Furthermore, the Stark broadening of the hydrogen Balmer H{sub {beta}} line is applied to measure the electron density, and the simultaneous presence of comparable Doppler, van der Waals, and instrumental broadenings is discussed. Besides, properties of the jet discharge are also studied by electrical diagnosis. It has been found that the electron densities in this argon plasma jet are on the order of 10{sup 14} cm{sup -3}, and the excitation temperature, gas temperature, and electron density increase with the applied voltage. On the other hand, these parameters are inversely proportional to the argon gas flow rate.

  11. Theoretical investigation of the effect of hydrogen addition on the formation and properties of soliton in direct current argon plasma

    SciTech Connect

    Saikia, P., E-mail: partha.008@gmail.com; Goswami, K. S.; Saikia, B. K. [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur, Kamrup, Assam-782 402 (India)] [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur, Kamrup, Assam-782 402 (India)

    2014-03-15

    In this study the effect of hydrogen addition on the formation and properties of soliton in direct-current (DC) argon plasma is theoretically investigated. By coupling fluid equations with Poisons equation for such multi-component plasma, the Mach number and amplitude of the soliton are determined following pseudo potential method. Addition of hydrogen in argon discharge leads to the decrease of electron, Ar{sup +} ion density while a reverse trend was observed for ArH{sup +} and hydrogen like ions. It was found that presence of hydrogen like ions in argon plasma affects the formation of soliton with its amplitude significantly decreases as concentration of hydrogen increases. On the other hand, increase in ion to electron temperature ratios of the lighter ions in the discharge also has a significant influence on the amplitude and formation of soliton. The inverse relation between solitons width and amplitude is found to be consistent for the entire range of study.

  12. Operating characteristics of a hydrogen-argon plasma torch for supersonic combustion applications

    NASA Technical Reports Server (NTRS)

    Barbi, E.; Mahan, J. R.; O'Brien, W. F.; Wagner, T. C.

    1989-01-01

    The residence time of the combustible mixture in the combustion chamber of a scramjet engine is much less than the time normally required for complete combustion. Hydrogen and hydrocarbon fuels require an ignition source under conditions typically found in a scramjet combustor. Analytical studies indicate that the presence of hydrogen atoms should greatly reduce the ignition delay in this environment. Because hydrogen plasmas are prolific sources of hydrogen atoms, a low-power, uncooled hydrogen plasma torch has been built and tested to evaluate its potential as a possible flame holder for supersonic combustion. The torch was found to be unstable when operated on pure hydrogen; however, stable operation could be obtained by using argon as a body gas and mixing in the desired amount of hydrogen. The stability limits of the torch are delineated and its electrical and thermal behavior documented. An average torch thermal efficiency of around 88 percent is demonstrated.

  13. Diagnostics of the influence of levitating microparticles on the radiofrequency argon plasma

    NASA Astrophysics Data System (ADS)

    Pustylnik, Mikhail Y.; Mitic, Slobodan; Klumov, Boris A.; Morfill, Gregor E.

    2010-11-01

    The effect of a levitating cloud of microparticles on the parameters of a radiofrequency (RF) plasma has been studied by means of two experimental techniques. Axial distributions of 1 s excited states of argon were measured by a self-absorption method. A correction of a standard self-absorption method for the extinction of the light by the levitating microparticles is proposed. In addition the electron temperature was estimated using the optical emission spectroscopy. Measurements at the same discharge conditions in a microparticle-free discharge and discharge, containing a cloud of levitating microparticles, revealed the non-local influence of the microparticle cloud on the discharge plasma. The most probable cause of this influence is the disturbance of the ionization balance by the levitating microparticles.

  14. Growth of thin silver films on silicon oxide pretreated by low temperature argon plasma

    NASA Astrophysics Data System (ADS)

    Romanyuk, Andriy; Steiner, Roland; Mack, Iris; Oelhafen, Peter; Mathys, Daniel

    2007-02-01

    In the present study, we investigate the influence of low energy ion bombardment on nucleation and growth of thin silver films on silicon oxide by in situ photoelectron spectroscopy (PES) combined with specific resistivity measurements. Thermally grown thin silicon oxide films were exposed to a low temperature argon plasma for different time intervals resulting in changes in surface chemical composition as monitored by angle-resolved X-ray photoelectron spectroscopy (ARXPS). We demonstrate that irradiation of the oxide surface with low energy ions results in substantially changed nucleation of silver. Furthermore, silver films deposited on plasma treated oxide tend to have lower resistivity which is attributed to the effect of reduced grain boundary and surface roughness.

  15. ULTRAVIOLET INDUCED MOTION OF A FLUORESCENT DUST CLOUD IN AN ARGON DIRECT CURRENT GLOW DISCHARGE PLASMA

    SciTech Connect

    Hvasta, M.G.; and Zwicker, A.

    2008-01-01

    Dusty plasmas consist of electrons, ions, neutrals and nm-?m sized particles commonly referred to as dust. In man-made plasmas this dust may represent impurities in a tokamak or plasma etching processing. In astrophysical plasmas this dust forms structures such as planetary rings and comet tails. To study dusty plasma dynamics an experiment was designed in which a 3:1 silica (<5 ?m diameter) and fl uorescent dust mixture was added to an argon DC glow discharge plasma and exposed to UV radiation. This fl uorescent lighting technique offers an advantage over laser scattering (which only allows two-dimensional slices of the cloud to be observed) and is simpler than scanning mirror techniques or particle image velocimetry. Under typical parameters (P=150 mTorr, V anode= 100 V, Vcathode= -400 V, Itotal < 2mA) when the cloud is exposed to the UV light (100W, ? = 365 nm) the mixture fl uoresces, moves ~2mm towards the light source and begins rotating in a clockwise manner (as seen from the cathode). By calibrating a UV lamp and adjusting the relative intensity of the UV with a variable transformer it was found that both translational and rotational velocities are a function of UV intensity. Additionally, it was determined that bulk cloud rotation is not seen when the dust tray is not grounded while bulk translation is. This ongoing experiment represents a novel way to control contamination in man-made plasmas and a path to a better understanding of UV-bathed plasma systems in space..

  16. Activation of plasma coagulation by retransfusion of unwashed drainage blood after hip joint arthroplasty

    Microsoft Academic Search

    Jochen Duchow; Michael Ames; Thomas Hess; Ulrich Seyfert

    2001-01-01

    Twelve patients undergoing cementless hip joint arthroplasty were retransfused with unwashed drainage blood collected postoperatively. Global coagulation parameters, coagulation factors (factor V:C, factor VIII:C, activated factor XII, and factor XIII) and markers of thrombin generation (F1+2 Fibrin split products, thrombin-antithrombin complexes), fibrin generation (fibrinogen and fibrin degradation products), and fibrinolysis (D-dimers, thrombin degradation products, plasminogen) were determined. High levels of

  17. Clinical Outcomes of Percutaneous Plasma Disc Coagulation Therapy for Lumbar Herniated Disc Diseases

    PubMed Central

    Kim, Sung Chul; Cho, Ki Hong

    2012-01-01

    Objective This is prospective study of clinical outcomes of percutaneous plasma disc coagulation Therapy (PDCT) in patients with herniated lumbar disc disease (HLD) to evaluate the safety and efficacy in its clinical application and usefulness as a reliable alternative to microscopic discectomy. Methods Forty-six patients were enrolled in this study from April 2006 to June 2010. All patients had one-level HLD. Disc degeneration was graded on routine T2-weighted magnetic resonance Image (MRI) using the Pfirrmann's grading system and all index levels were grade 3 and grade 4. Indications for surgery were radiculopathy caused by disc protrusion with soft consistency. MRI was done at one month after the procedure in all patients to check post-PDCT change. The clinical outcomes were evaluated using Visual Analog Scales (VAS) score and MacNab's criteria. Results This study was approved by the Institutional Review Board of our institution. The age of the study population ranged from 16 to 59 years with a mean age of 37.2 years. There were 29 males and 17 females in this study. The mean period of clinical follow-up was 21 months. The average preoperative VAS score for radiculopathy was 7.4±1.4, while the final follow-up VAS score was 1.4±0.7 (p<0.001). In MacNab's criteria, 41 patients (89.1%) had achieved favorable improvement (excellent and good) until later follow-up. There were one patient from infection and two patients who needed to convert to open discectomy. Conclusion PDCT is a safe and efficient treatment modality in a selective patient with HLD. PMID:22396836

  18. Drugs Modifying Nitric Oxide Metabolism Affect Plasma Cholesterol Levels, Coagulation Parameters, Blood Pressure Values and the Appearance of Plasma Myocardial Necrosis Markers in Rabbits: Opposite Effects of L-NAME and Nitroglycerine

    Microsoft Academic Search

    Arnaldo Pinelli; Silvio Trivulzio; Livio Tomasoni; Boris Bertolini; Sergio Brenna; Edgardo Bonacina; Roberto Accinni

    2003-01-01

    Various experiments have shown that decreased nitric oxide values alter plasma lipid levels or coagulation parameters or blood pressure values or cause myocardial necrosis phenomena, but it is not clear whether these alterations are reciprocally connected, or whether nitric oxide changes are involved in the appearance of some coronary disease risk factors (lipid, coagulation, blood pressure alterations) and myocardial necrosis.

  19. Temporally and spatially resolved characterization of microwave induced argon plasmas: Experiment and modeling

    SciTech Connect

    Baeva, M., E-mail: baeva@inp-greifswald.de; Andrasch, M.; Ehlbeck, J.; Loffhagen, D.; Weltmann, K.-D. [INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)

    2014-04-14

    Experiments and modeling of the plasma-microwave interaction have been performed in a coaxial microwave plasma source at a field frequency of 2.45 GHz generating argon plasmas at pressures of 20 and 40 millibars and a ratio of flow rate to pressure of 0.125 sccm/Pa. The incident microwave power between 100?W and 300?W is supplied in a regime of a pulse-width modulation with cycle duration of 110?ms and a power-on time of 23?ms. The experiments are based on heterodyne reflectometry and microwave interferometry at 45.75?GHz. They provide the temporal behaviour of the complex reflection coefficient, the microwave power in the plasma, as well as the electron density in the afterglow zone of the discharge. The self-consistent spatially two-dimensional and time-dependent modeling complements the analysis of the plasma-microwave interaction delivering the plasma and electromagnetic field parameters. The consolidating experimental observations and model predictions allow further characterizing the plasma source. The generated plasma has a core occupying the region close to the end of the inner electrode, where maximum electron densities above 10{sup 20}?m{sup ?3} and electron temperatures of about 1?eV are observed. Due to a longer outer electrode of the coaxial structure, the plasma region is extended and fills the volume comprised by the outer electrode. The electron density reaches values of the order of 10{sup 19}?m{sup ?3}. The heating of the gas occurs in its great part due to elastic collisions with the plasma electrons. However, the contribution of the convective heating is important especially in the extended plasma region, where the gas temperature reaches its maximum values up to approximately 1400?K. The temporally and spatially resolved modeling enables a thorough investigation of the plasma-microwave interaction which clearly shows that the power in-coupling occurs in the region of the highest electron density during the early stage of the discharge. In the steady state phase, however, the power in-coupling occurs close to the source walls where the electron density is significantly lower than on the discharge axis.

  20. Absorption Spectroscopy Measurements of Ion Velocity Distribution Functions in Argon Plasmas.

    NASA Astrophysics Data System (ADS)

    Scime, Earl; Przybysz, William S.

    2007-11-01

    The scarcity of strong absorption lines in accessible tuning ranges along with plasma saturation due to low ion population densities makes absorption spectroscopy of helium ions notoriously difficult. Helicon plasmas, with their characteristically high ion densities, are a good candidate for initial helium ion spectroscopy experiments. However, preliminary measurements of Doppler broadened ion velocity distribution functions (ivdf) involving injecting a tunable infrared diode laser, tuned to 1012.36 nm and chopped roughly at 1kHz, along the axis of a 1.5m long helicon plasma have yielded erratic and irreproducible measurements. Here we present absorption spectroscopy measurements of ivdfs in argon helicon plasma using a tunable diode laser at 668.43 nm to pump the Ar II metastable 3d^4F7/2 level to the 4p^4D5/2 level. The optimized multi-pass optical configuration and the ratioing detector will be described and initial measurements presented. Once the absorption measurement technique is optimized for the well-known and more easily diagnosed Ar II transition, the same experimental configuration will then be used for the infrared helium ion absorption measurement

  1. Comparative analysis of activity of coagulation Factors V and VIII and level of fibrinogen in fresh frozen plasma and frozen plasma

    PubMed Central

    Dogra, Mitu; Sidhu, Meena; Vasudev, Rahul; Dogra, Ashu

    2015-01-01

    Background: The aim of this study was to analyse and compare the activity of factor V, VIII and fibrinogen level in fresh frozen plasma and frozen plasma frozen after 8 hrs but within 24 hours after phlebotomy. Materials and Methods: Fresh frozen plasma separated from whole blood within 8 hours was compared with plasma separated within 24 hours after phlebotomy in terms of coagulation factors V and VIII and level of fibrinogen by standard methods using semi automated coagulometer sysmex CA50. Results: Longer storage of whole blood before processing resulted in significant decrease (18.4%) in activity of factor VIII but the fall in activity of factor V (6.52%) or level of fibrinogen (1.81%) was not significant. Discussion: These data suggest that there is good retention of coagulation factors in both types of plasma. Although there is significant fall in activity of factor VIII, but it is an acute phase reactant and raised in most of the diseases so it is suggested that frozen plasma would be an acceptable product for most patients requiring fresh frozen plasma. PMID:25722564

  2. Two-dimensional argon metastable density measurements in a radio frequency plasma reactor by planar laser-induced Jluorescence imaging

    E-print Network

    Zachariah, Michael R.

    Two-dimensional argon metastable density measurements in a radio frequency plasma reactor by planar-of-sight absorption, or single-point laser-induced fluorescence.iv6 To our knowledge, the only complete two, the measurements cover a wide range of conditions and were performed in a well- characterized reactor (the Gaseous

  3. Study of emission of a volume nanosecond discharge plasma in xenon, krypton and argon at high pressures

    Microsoft Academic Search

    E Kh Baksht; Mikhail I Lomaev; D V Rybka; Viktor F Tarasenko

    2006-01-01

    The emission properties of a volume nanosecond discharge plasma produced in xenon, krypton and argon at high pressures in a discharge gap with a cathode having a small radius of curvature are studied. Spectra in the range 120–850 nm and amplitude—time characteristics of xenon emission at different regimes and excitation techniques are recorded and analysed. It is shown that upon

  4. ANALYSIS OF A WASTEWATER FOR SEVEN PRIORITY POLLUTANT ELEMENTS BY D.C. ARGON PLASMA EMISSION SPECTROSCOPY

    EPA Science Inventory

    This limited project was conducted to determine the usefulness of the D.C. argon plasma for the analysis of wastewater. Seven priority pollutant elements, arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), and thallium (Tl), were selected for use i...

  5. Dynamics of plasma expansion and shockwave formation in femtosecond laser-ablated aluminum plumes in argon gas at atmospheric pressures

    E-print Network

    Harilal, S. S.

    in argon gas at atmospheric pressures Alexander Miloshevsky, Sivanandan S. Harilal, Gennady Miloshevsky formation in fs-pulse and ns-pulse laser ablated Al plumes in an ambient gas at atmospheric pressures. VC plasma expansion into a background gas at atmospheric pressure is cru- cial for many engineering

  6. Scanning-electron-microscopy study of argon-plasma-treated and untreated peel-test Kevlar 49/epoxy laminates

    SciTech Connect

    Ingraham, J.A.; Walton, J.; Pruneda, C.O.; Morgan, R.J.

    1982-10-01

    It is concluded that a 200-watt RF argon plasma treatment of Kevlar fibers for four minutes increases the fiber/epoxy interfacial bonding. However, as a consequence of this increase in fiber-matrix bonding, the fiber is readily fibrillated during laminate deformation and failure.

  7. Radiative properties of argon–helium–nitrogen–carbon–cobalt–nickel plasmas used in CNT synthesis

    NASA Astrophysics Data System (ADS)

    Salem, D.; Hannachi, R.; Cressault, Y.; Teulet, Ph; Béji, L.

    2015-02-01

    This work presents the radiative properties of argon–helium–nitrogen–carbon–nickel–cobalt thermal plasmas by the computation of net emission coefficients (NECs) under the assumption of a local thermodynamic equilibrium and at temperature range 1000–20?000?K. These mixtures were often used in the study of carbon nanotubes (CNTs) synthesis with arc plasma which becomes one of the most useful techniques in terms of flexibility of carbon nanostructures produced with fewer defects. The values of NEC allow estimation of total radiation losses in plasmas, by taking into account the emission radiation resulting from the atomic continuum, the molecular continuum, the atomic lines and some molecular bands. Free–free transitions (Bremsstrahlung) and free–bound (electron–ion recombination), have been considered for the calculation of atomic continuum. For bound–bound transitions, natural, resonance, Van der Waals, Stark and Doppler effects have been taken into account in the calculation of the lines broadenings while the self-absorption of the resonance lines has been treated using their escape factors. Molecular continuum has been only considered for N2, C2 and CN molecules whereas we have only taken into account diatomic systems N2, \\text{N}2+ , CN and C2 for the emission of the molecular bands. The results obtained show that even for low concentrations of Ni and Co in the plasma, the NECs are modified and considerably increase only at a low temperature (T < 8000?K) and the major contribution in the total radiation arises from the lines emission. However, the effect of the thickness of the plasma on plasma radiation has been analysed based on the self absorption phenomenon of resonance lines.

  8. Development of a diffuse air-argon plasma source using a dielectric-barrier discharge at atmospheric pressure

    SciTech Connect

    Tang Jie; Jiang Weiman; Zhao Wei; Wang Yishan; Li Shibo; Wang Haojing [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China)] [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China); Duan Yixiang [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China) [State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119 (China); Research Center of Analytical Instrumentation, Sichuan University, Chengdu 610064 (China)

    2013-01-21

    A stable diffuse large-volume air plasma source was developed by using argon-induced dielectric-barrier discharges at atmospheric pressure. This plasma source can be operated in a filamentary discharge with the average areal power density of 0.27 W/cm{sup 2} and the gas temperature of 315{+-}3 K. Spatial measurement of emission spectrum and temperature indicates that this plasma is uniform in the central region along the transverse direction. It is also found that the formation of diffuse air plasma mainly lies in the creation of sufficient seed electrons by the Penning effect through collisions between two argon or nitrogen metastables at low electric fields.

  9. Effect of dielectric wall temperature on plasma plume in an argon atmospheric pressure discharge

    NASA Astrophysics Data System (ADS)

    Song, Jian; Tang, Jingfeng; Huo, Yuxin; Wei, Liqiu; Wang, Youyin; Yu, Daren

    2014-10-01

    In this letter, the effect of the dielectric wall temperature on the length and volume of an atmospheric pressure plasma jet (APPJ) is investigated using a single-electrode configuration driven with an AC power supply. To distinguish the APPJ status from the argon flow rate, the three modes, laminar, transition, and turbulent, are separated. When the dielectric wall is heated, the APPJ length and volume are enhanced. Also, the transition regions remarkably expand over a large range of flow rates. The results indicate that different factors contribute to the expansion of the transition region. The increase in the radial and axial velocities is the main cause of the expansion of the transition region to the low-velocity region. The expansion to the high-velocity region is dominantly induced by a change in the viscosity.

  10. Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus

    SciTech Connect

    Mohammadnejad, M.; Pestehe, S. J.; Mohammadi, M. A. [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Postal Code 5166614766, Tabriz (Iran, Islamic Republic of) [Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Postal Code 5166614766, Tabriz (Iran, Islamic Republic of); Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz (Iran, Islamic Republic of)

    2013-07-15

    The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy.

  11. Effect of dielectric wall temperature on plasma plume in an argon atmospheric pressure discharge

    SciTech Connect

    Song, Jian; Huo, Yuxin; Wang, Youyin; Yu, Daren, E-mail: yudaren@hit.edu.cn [School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Tang, Jingfeng; Wei, Liqiu [Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150001 (China)

    2014-10-15

    In this letter, the effect of the dielectric wall temperature on the length and volume of an atmospheric pressure plasma jet (APPJ) is investigated using a single-electrode configuration driven with an AC power supply. To distinguish the APPJ status from the argon flow rate, the three modes, laminar, transition, and turbulent, are separated. When the dielectric wall is heated, the APPJ length and volume are enhanced. Also, the transition regions remarkably expand over a large range of flow rates. The results indicate that different factors contribute to the expansion of the transition region. The increase in the radial and axial velocities is the main cause of the expansion of the transition region to the low-velocity region. The expansion to the high-velocity region is dominantly induced by a change in the viscosity.

  12. Exploring the electron density in plasmas induced by extreme ultraviolet radiation in argon

    E-print Network

    van der Horst, R M; Osorio, E A; Banine, V Y

    2015-01-01

    The new generation of lithography tools use high energy EUV radiation which ionizes the present background gas due to photoionization. To predict and understand the long term impact on the highly delicate mirrors It is essential to characterize these kinds of EUV-induced plasmas. We measured the electron density evolution in argon gas during and just after irradiation by a short pulse of EUV light at 13.5 nm by applying microwave cavity resonance spectroscopy. Dependencies on EUV pulse energy and gas pressure have been explored over a range relevant for industrial applications. Our experimental results show that the maximum reached electron density depends linearly on pulse energy. A quadratic dependence - caused by photoionization and subsequent electron impact ionization by free electrons - is found from experiments where the gas pressure is varied. This is demonstrated by our theoretical estimates presented in this manuscript as well.

  13. ATOMIC AND MOLECULAR PHYSICS: Radiative Transition Line Shape in Warm and Dense Argon Plasma: a Two-Centre Model Study

    Microsoft Academic Search

    Cong-Sen Meng; Zeng-Xiu Zhao; Jian-Min Yuan

    2008-01-01

    A two-centre model is employed to study the electronic structure of argon plasma at a density of 1022 cm-3 and a temperature of 5eV. The model takes into account the influence of the nearest neighbour on the electronic structure of the radiator and gives a proper description of the transient molecular behaviour in dense plasmas where the mean interatomic distance

  14. Characterization of a low temperature atmospheric-pressure argon microwave induced plasma using visual imaging, OES, and CRDS combined

    Microsoft Academic Search

    C. Wang; N. Srivastava; S. Scherrer; P. R. Jang; T. S. Dibble; Y. Duan

    2009-01-01

    We employ a suite of optical techniques, visual imaging, optical emission spectroscopy (OES), and cavity ringdown spectroscopy (CRDS), to characterize a low power, low gas flow rates, atmospheric-pressure argon microwave induced plasma (MIP). A series of plasma images captured in a time resolution range of 10 mus-0.05 s shows that the converging point is a visual effect of integrating the

  15. Determination of gas-temperature and velocity profiles in an argon thermal-plasma jet by laser-light scattering

    Microsoft Academic Search

    S. C. Snyder; L. D. Reynolds; G. D. Lassahn; J. R. Fincke; C. B. Jr. Shaw; R. J. Kearney

    1993-01-01

    Gas-temperature and velocity profiles at the exit plane of a thermal argon plasma torch have been determined directly from a high-resolution Doppler-shifted line-shape analysis of laser light scattered by the plasma. Peak temperature and velocity values observed were 13 350 K[plus minus]7% and 1100 m s[sup [minus]1][plus minus]3%. Velocities as low as 45 m s[sup [minus]1][plus minus]45% were measured in

  16. Investigation of magnetic-pole-enhanced inductively coupled nitrogen-argon plasmas

    SciTech Connect

    Jan, F.; Zakaullah, M. [Department of Physics, Quaid-i-Azam University Islamabad, Islamabad 45320 (Pakistan); Khan, A. W.; Saeed, A. [National Centre for Physics, Quaid-i-Azam University Campus Islamabad, Islamabad 45320 (Pakistan)

    2012-09-15

    This article presented the features of the mixed mode and H mode in magnetic pole enhanced, inductively coupled Ar-N{sub 2} plasmas using RF-compensated Langmuir probe measurements. To fully characterize plasma parameters and electron energy probability functions (EEPFs), the gas pressure and argon content were varied. It was observed that with increasing the nitrogen content and gas pressure, the critical RF power to sustain H mode increases; this increase was more prominent for pure nitrogen discharge at higher pressure. The electron number density (n{sub e}) shows increasing trend with increasing RF power, while at higher gas pressures, the electron number density decreases at fixed RF power. Mostly, the EEPFs show a Maxwellian distribution even at low RF power (for higher argon content in the discharge) and at moderate RF power (for higher or pure nitrogen content in the discharge) for pressures of 15-60 mTorr. With increasing the nitrogen content in the mixture, the low energy part of the EEPF is more Druyvesteyn with a distorted high energy tail at low RF power. At fixed RF power, the slope of EEPF changes sharply with increasing pressure. It was observed that in hybrid mode, the EEPF at higher gas pressure (75 mTorr) in a pure nitrogen discharge shows a flat hole near the average electron energy of 3 eV and changes to Maxwellian distribution in H mode. The skin depth versus RF power shows that the skin depth is smaller than the critical dimension of the chamber, regardless of the gas type and the gas pressure.

  17. Effect of process parameters on properties of argon–nitrogen plasma for titanium nitride film deposition

    SciTech Connect

    Saikia, Partha; Kakati, Bharat [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782 402, Kamrup, Assam (India)] [Centre of Plasma Physics, Institute for Plasma Research, Nazirakhat, Sonapur-782 402, Kamrup, Assam (India)

    2013-11-15

    In this study, the effect of working pressure and input power on the physical properties and sputtering efficiencies of argon–nitrogen (Ar/N{sub 2}) plasma in direct current magnetron discharge is investigated. The discharge in Ar/N{sub 2} is used to deposit TiN films on high speed steel substrate. The physical plasma parameters are determined by using Langmuir probe and optical emission spectroscopy. On the basis of the different reactions in the gas phase, the variation of plasma parameters and sputtering rate are explained. A prominent change of electron temperature, electron density, ion density, and degree of ionization of Ar is found as a function of working pressure and input power. The results also show that increasing working pressure exerts a negative effect on film deposition rate while increasing input power has a positive impact on the same. To confirm the observed physical properties and evaluate the texture growth as a function of deposition parameters, x-ray diffraction study of deposited TiN films is also done.

  18. Pulsed microwave-driven argon plasma jet with distinctive plume patterns resonantly excited by surface plasmon polaritons

    NASA Astrophysics Data System (ADS)

    Chen, Zhao-Quan; Yin, Zhi-Xiang; Xia, Guang-Qing; Hong, Ling-Li; Hu, Ye-Lin; Liu, Ming-Hai; Hu, Xi-Wei; A. Kudryavtsev, A.

    2015-02-01

    Atmospheric lower-power pulsed microwave argon cold plasma jets are obtained by using coaxial transmission line resonators in ambient air. The plasma jet plumes are generated at the end of a metal wire placed in the middle of the dielectric tubes. The electromagnetic model analyses and simulation results suggest that the discharges are excited resonantly by the enhanced electric field of surface plasmon polaritons. Moreover, for conquering the defect of atmospheric argon filamentation discharges excited by 2.45-GHz of continued microwave, the distinctive patterns of the plasma jet plumes can be maintained by applying different gas flow rates of argon gas, frequencies of pulsed modulator, duty cycles of pulsed microwave, peak values of input microwave power, and even by using different materials of dielectric tubes. In addition, the emission spectrum, the plume temperature, and other plasma parameters are measured, which shows that the proposed pulsed microwave plasma jets can be adjusted for plasma biomedical applications. Project supported by the National Natural Science Foundation of China (Grant Nos. 11105002 and 61170172), the Natural Science Foundation of Anhui Province, China (Grant Nos. 1408085QA16 and 1408085ME101), the China Postdoctoral Science Foundation (Grant No. 2014M551788), and the Open-end Fund of State Key Laboratory of Advanced Electromagnetic Engineering and Technology (HUST), China (Grant No. GZ1301).

  19. Net emission coefficients of argon iron plasmas with electron Stark widths scaled to experiments

    NASA Astrophysics Data System (ADS)

    Wendt, M.

    2011-03-01

    The net emission coefficient of plasmas containing argon and iron at atmospheric pressure is calculated and analysed for the case of cylindrical geometry. Its values are obtained by integrating the monochromatic net emission coefficient taking into account continuous and line radiation. The width of the spectral lines is determined by Doppler broadening, natural, resonance, van der Waals, electron and ion Stark broadening. As Stark broadening is the most important broadening mechanism in the considered pressure and temperature range, the electron Stark widths are calculated following the semi-empirical Stark broadening theory. Additionally, the electron Stark widths of Ar, Ar+, Fe and Fe+ are multiplied by scaling factors in order to reproduce experimental electron Stark widths. The scaling factor is determined for each species separately. For small plasma radii the net emission coefficient determined here shows good agreement with literature values where spherical geometry is considered while they decrease faster with increasing plasma radius. This behaviour is caused by the increase of the irradiation of the symmetry axis when cylindrical instead of spherical geometry is considered. For radii and temperatures typical of the metal filled core of arcs occurring in gas metal arc welding processes, i.e. radii between 1 and 2 × 10-3 m and temperatures between 5000 and 10 000 K, the scaling of the Stark widths increases the net emission coefficient of iron plasmas by between 2% and 23%. In this parameter range the net emission coefficient of iron plasmas for cylindrical geometry is between 30% and 37% smaller than values calculated for spherical geometry.

  20. Characteristics of an atmospheric microwave-induced plasma generated in ambient air by an argon discharge excited in an open-ended dielectric discharge tube

    Microsoft Academic Search

    Se Youn Moon; W. Choe; Han S. Uhm; Y. S. Hwang; J. J. Choi

    2002-01-01

    Parametric observations on an atmospheric-pressure plasma sustained in ambient air by an argon discharge excited by 2.45 GHz microwaves in an open-ended dielectric discharge tube are reported. Microwave power, discharge tube dimensions, and argon flow rate were the major operating parameters. Three distinctive plasma regions were observed: plasma filaments exiting from the discharge tube, converging point of these filaments, and

  1. Comparison of functional aspects of the coagulation cascade in human and sea turtle plasmas

    Microsoft Academic Search

    Gerald Soslau; Bryan Wallace; Catherine Vicente; Seth J. Goldenberg; Todd Tupis; James Spotila; Robert George; Frank Paladino; Brent Whitaker; Gary Violetta; Rotney Piedra

    2004-01-01

    Functional hemostatic pathways are critical for the survival of all vertebrates and have been evolving for more than 400 million years. The overwhelming majority of studies of hemostasis in vertebrates have focused on mammals with very sparse attention paid to reptiles. There have been virtually no studies of the coagulation pathway in sea turtles whose ancestors date back to the

  2. Bactericidal effects of non-thermal argon plasma in vitro, in biofilms and in the animal model of infected wounds.

    PubMed

    Ermolaeva, Svetlana A; Varfolomeev, Alexander F; Chernukha, Marina Yu; Yurov, Dmitry S; Vasiliev, Mikhail M; Kaminskaya, Anastasya A; Moisenovich, Mikhail M; Romanova, Julia M; Murashev, Arcady N; Selezneva, Irina I; Shimizu, Tetsuji; Sysolyatina, Elena V; Shaginyan, Igor A; Petrov, Oleg F; Mayevsky, Evgeny I; Fortov, Vladimir E; Morfill, Gregor E; Naroditsky, Boris S; Gintsburg, Alexander L

    2011-01-01

    Non-thermal (low-temperature) physical plasma is under intensive study as an alternative approach to control superficial wound and skin infections when the effectiveness of chemical agents is weak due to natural pathogen or biofilm resistance. The purpose of this study was to test the individual susceptibility of pathogenic bacteria to non-thermal argon plasma and to measure the effectiveness of plasma treatments against bacteria in biofilms and on wound surfaces. Overall, Gram-negative bacteria were more susceptible to plasma treatment than Gram-positive bacteria. For the Gram-negative bacteria Pseudomonas aeruginosa, Burkholderia cenocepacia and Escherichia coli, there were no survivors among the initial 10(5) c.f.u. after a 5 min plasma treatment. The susceptibility of Gram-positive bacteria was species- and strain-specific. Streptococcus pyogenes was the most resistant with 17?% survival of the initial 10(5) c.f.u. after a 5 min plasma treatment. Staphylococcus aureus had a strain-dependent resistance with 0 and 10?% survival from 10(5) c.f.u. of the Sa 78 and ATCC 6538 strains, respectively. Staphylococcus epidermidis and Enterococcus faecium had medium resistance. Non-ionized argon gas was not bactericidal. Biofilms partly protected bacteria, with the efficiency of protection dependent on biofilm thickness. Bacteria in deeper biofilm layers survived better after the plasma treatment. A rat model of a superficial slash wound infected with P. aeruginosa and the plasma-sensitive Staphylococcus aureus strain Sa 78 was used to assess the efficiency of argon plasma treatment. A 10 min treatment significantly reduced bacterial loads on the wound surface. A 5-day course of daily plasma treatments eliminated P. aeruginosa from the plasma-treated animals 2 days earlier than from the control ones. A statistically significant increase in the rate of wound closure was observed in plasma-treated animals after the third day of the course. Wound healing in plasma-treated animals slowed down after the course had been completed. Overall, the results show considerable potential for non-thermal argon plasma in eliminating pathogenic bacteria from biofilms and wound surfaces. PMID:20829396

  3. The inactivation of Staphylococcus aureus biofilms using low-power argon plasma in a layer-by-layer approach.

    PubMed

    Traba, Christian; Liang, Jun F

    2015-01-01

    The direct application of low power argon plasma for the decontamination of pre-formed Staphylococcus aureus biofilms on various surfaces was examined. Distinct chemical/physical properties of reactive species found in argon plasmas generated at different wattages all demonstrated very potent but very different anti-biofilm mechanisms of action. An in-depth analysis of the results showed that: (1) the different reactive species produced in each plasma demonstrated specific antibacterial and/or anti-biofilm activity; and (2) the commonly associated etching effect could be manipulated and even controlled, depending on the experimental conditions. Under optimal experimental parameters, bacterial cells in S. aureus biofilms were killed (> 99.9%) by plasmas within 10 min of exposure and no bacteria nor biofilm regrowth from argon discharge gas treated biofilms was observed for 150 h. The decontamination ability of plasmas for the treatment of biofilm related contaminations on various materials was confirmed and an entirely novel layer-by-layer decontamination approach was designed and examined. PMID:25569189

  4. Presheath and Double Layer Structures in an Argon Helicon Plasma Source

    NASA Astrophysics Data System (ADS)

    Siddiqui, M. Umair

    Ion velocities and temperatures, plasma density, potential, and electron temperatures are measured in a 13.56 MHz helicon produced argon plasma upstream from a grounded plate inside a 10 cm ID cylindrical Pyrex vacuum chamber. The plate is held at psi = 0° ? 60° relative to the background axial magnetic field in the system. For the psi = 0° experiment, two distinct helicon discharge equilibria are observed at 500 W rf power, 900 G magnetic field, and a neutral pressure of 3 ? 4 mTorr. Both modes exhibit a localized region of hot electrons (Th ? 10 eV, Tc ? 3.5 eV). For the first mode the hot electrons are confined by a localized potential structure and the density decreases monotonically towards the grounded plate. For the second mode the hot electrons cool off gradually in space due to heat conduction generating a downstream density peak and no major potential structures are observed. It is found that the type of discharge mode is determined by the location of the grounded plate, the length of the presheath, and the rf electron heating mechanism. For the psi = 16° ? 60° plate positions, ion flow to the boundary where a 1 kG magnetic field is obliquely incident is measured at 1, 3, and 6.5 mTorr neutral pressure and 450 ? 750 W rf power. The results are compared to the magnetic presheath models put forth by Chodura [Phys. Fluids 25, 1628 (1982)], Riemann [Phys. Plasmas 1, 552 (1994)], and Ahedo [Phys. Plasmas 4, 4419 (1997)]. The 1 mTorr dataset is used to benchmark a one-dimensional fluid model for the ion flow in the presheath. Definitions of the "magnetic presheath" are discussed. The fluid model in conjuction with the data show that the ion velocities in the E x B direction can be 10% ? 40% percent of the sound speed for the angles investigated. Ion flow to fusion experiment boundaries and Hall thruster walls is discussed.

  5. Spatially resolved Langmuir probe diagnostics in a capacitively coupled radio frequency argon and oxygen plasma

    NASA Astrophysics Data System (ADS)

    Küllig, C.; Wegner, Th; Meichsner, J.

    2015-02-01

    Axial and radial profiles of the positive ion saturation current were measured by Langmuir probe diagnostics in a capacitively coupled radio frequency (RF) plasma in argon and oxygen. Under certain conditions these profiles provide the spatial density distribution of the positive ions, which corresponds approximately to the electron density in the electropositive plasma. Particularly in oxygen at low RF power a peak in the ion saturation current appears in the radial direction at the electrode boundary. The axial position s at the maximum ion saturation current depends on total pressure with s ? p?1/3, which reveals the pressure dependence of a collisional RF sheath. Furthermore, Langmuir probe characteristics were evaluated in terms of the Druyvesteyn method to determine the radial behavior of the electron energy probability function (EEPF). From the EEPF the radially resolved effective electron temperature and electron density were calculated. The radial electron density profile from the Langmuir probe was numerically integrated to calculate a line integrated electron density for comparison with the measured line integrated density from 160 GHz microwave interferometry. The integration over the Langmuir probe density results in a line integrated density, which amounts to 40% of the line integrated density from microwave interferometry.

  6. Spatio-temporal evolution of the dust particle size distribution in dusty argon rf plasmas

    NASA Astrophysics Data System (ADS)

    Killer, Carsten; Mulsow, Matthias; Melzer, André

    2015-04-01

    An imaging Mie scattering technique has been developed to measure the spatially resolved size distribution of dust particles in extended dust clouds. For large dust clouds of micrometre-sized plastic particles confined in an radio frequency (rf) discharge, a segmentation of the dust cloud into populations of different sizes is observed, even though the size differences are very small. The dust size dispersion inside a population is much smaller than the difference between the populations. Furthermore, the dust size is found to be constantly decreasing over time while the particles are confined in an inert argon plasma. The processes responsible for the shrinking of the dust in the plasma have been addressed by mass spectrometry, ex situ microscopy of the dust size, dust resonance measurements, in situ determination of the dust surface temperature and Fourier transform infrared absorption (FT-IR). It is concluded that both a reduction of dust size and its mass density due to outgassing of water and other volatile constituents as well as chemical etching by oxygen impurities are responsible for the observations.

  7. Mechanism of forward development of a plasma produced by an excimer laser in high-pressure argon gases

    NASA Astrophysics Data System (ADS)

    Tsuda, Norio; Yamada, Jun

    2000-03-01

    In high-pressure argon gases up to 150 atm, the plasma produced by a XeCl excimer laser developed not only backward but also forward. The model for the forward development, called a forward breakdown wave, could not predict the developmental behavior in the latter stage. The development model was modified, newly taking into account the laser absorption by the plasma when the laser light was transmitted through the backward plasma. The time variation of the absorption coefficient at each distance was calculated using the inverse bremsstrahlung by the electron-ion impact. This modified model could better predict the forward development behavior than the previous model.

  8. E-H mode transition in low-pressure inductively coupled nitrogen-argon and oxygen-argon plasmas

    NASA Astrophysics Data System (ADS)

    Lee, Young Wook; Lee, Hye Lan; Chung, T. H.

    2011-06-01

    This work investigates the characteristics of the E-H mode transition in low-pressure inductively coupled N2-Ar and O2-Ar discharges using rf-compensated Langmuir probe measurements and optical emission spectroscopy (OES). As the ICP power increases, the emission intensities from plasma species, the electron density, the electron temperature, and the plasma potential exhibit sudden changes. The Ar content in the gas mixture and total gas pressure have been varied in an attempt to fully characterize the plasma parameters. With these control parameters varying, the changes of the transition threshold power and the electron energy distribution function (EEDF) are explored. In N2-Ar and O2-Ar discharges at low-pressures of several millitorr, the transition thresholds are observed to decrease with Ar content and pressure. It is observed that in N2-Ar plasmas during the transition, the shape of the EEDF changes from an unusual distribution with a flat hole near the electron energy of 3 eV in the E mode to a Maxwellian distribution in the H mode. However, in O2 -Ar plasmas, the EEDFs in the E mode at low Ar contents show roughly bi-Maxwellian distributions, while the EEDFs in the H mode are observed to be nearly Maxwellian. In the E and H modes of O2-Ar discharges, the dissociation fraction of O2 molecules is estimated using optical emission actinometry. During the E-H mode transition, the dissociation fraction of molecules is also enhanced.

  9. Predicting the presence of plasma heparin using neural networks to analyze coagulation screening assay optical profiles.

    PubMed

    Givens, T B; Braun, P; Fischer, T J

    1996-11-01

    A method for predicting the presence of heparin from coagulation screening assays is described and data are presented. This method incorporates the use of a multilayer perceptron trained through an error back-propagation algorithm in analyzing clotting optical data profiles. This method may lead to the identification of abnormalities from screening assays that might otherwise go undetected, or require additional testing to isolate. PMID:8997540

  10. X-ray Photoelectron Spectroscopy Study of Argon-Plasma-Treated Fluoropolymers

    NASA Technical Reports Server (NTRS)

    Golub, Morton A.; Lopata, Eugene S.; Finney, Lorie S.

    1994-01-01

    Films of poly(tetrafluoroethylene) (PTFE) and of a tetrafluoroethylene-perfluoroalkyl vinyl ether (approximately 49:1) copolymer (PFA) were exposed to a radio-frequency argon plasma and then examined by X-ray photoelectron spectroscopy (XPS). The use of fluoropolymer films nearly free of surface hydrocarbon contamination as well as the use of a monochromatized X-ray source for XPS removed two factors contributing to conflicting reports on the effect of exposure time on the fluorine-to-carbon (F/C) and oxygen-to-carbon (O/C) ratios for several Ar-plasma-treated fluoropolymers. Contrary to literature indications, a common pattern was found for PTFE and PFA: a moderate decrease in F/C ratio (from 1.99 to 1.40, and from 1.97 to 1.57, respectively), together with a moderate increase in O/C ratio (from negligible to about 0.10, and from 0.012 to about O.10, respectively) at very short exposures, after which the F/C ratios remained essentially constant on prolonged exposures, while the O/C ratios for PTFE and PFA leveled off at 0.11 and 0.15, respectively. The XPS C(sub 1s), spectra for these polymers exposed to the Ar plasma for 20 min were similar and presented, besides a prominent peak at 292.0 eV (CF2,) and a minor peak at 294.0 or 294.1 eV (CF3), a composite band of four curve-resolved peaks (approximately 285-290 eV) representing various CH, CC, CO, CN, and CF functionalities.

  11. Plasma/particle interaction in subsonic argon/helium thermal plasma jets

    SciTech Connect

    Swank, W.D.; Fincke, J.R.; Haggard, D.C.

    1993-04-01

    Understanding the behavior of a particle and the interactions between a particle and the plasma surrounding it is important to the development and optimization of the plasma spray coating process. This is an experimental study of the interaction between a subsonic thermal plasma jet and injected nickel-aluminum particles. The velocity, temperature and composition of the gas flow field is mapped using an enthalpy probe/mass spectrometer system. The particle flow field is examined by simultaneously measuring the in-flight size, velocity, and temperature of individual particles. The complex interaction between the gas and particle flow fields is examined by combining the two sets of data. Particle and gas temperatures and velocities are compared in the vicinity of a nominal substrate standoff distance and axially along the median particle trajectory. The temperature and velocity difference is shown to vary substantially depending on the particle`s trajectory. By the time a particle on the median trajectory reaches the nominal substrate stand off of 63.5 mm it is transferring it`s heat and momentum to the plasma gas.

  12. Plasma/particle interaction in subsonic argon/helium thermal plasma jets

    SciTech Connect

    Swank, W.D.; Fincke, J.R.; Haggard, D.C.

    1993-01-01

    Understanding the behavior of a particle and the interactions between a particle and the plasma surrounding it is important to the development and optimization of the plasma spray coating process. This is an experimental study of the interaction between a subsonic thermal plasma jet and injected nickel-aluminum particles. The velocity, temperature and composition of the gas flow field is mapped using an enthalpy probe/mass spectrometer system. The particle flow field is examined by simultaneously measuring the in-flight size, velocity, and temperature of individual particles. The complex interaction between the gas and particle flow fields is examined by combining the two sets of data. Particle and gas temperatures and velocities are compared in the vicinity of a nominal substrate standoff distance and axially along the median particle trajectory. The temperature and velocity difference is shown to vary substantially depending on the particle's trajectory. By the time a particle on the median trajectory reaches the nominal substrate stand off of 63.5 mm it is transferring it's heat and momentum to the plasma gas.

  13. E-H mode transition in low-pressure inductively coupled nitrogen-argon and oxygen-argon plasmas

    SciTech Connect

    Lee, Young Wook; Lee, Hye Lan; Chung, T. H. [Department of Physics, Dong-A University, Busan 604-714 (Korea, Republic of)

    2011-06-01

    This work investigates the characteristics of the E-H mode transition in low-pressure inductively coupled N{sub 2}-Ar and O{sub 2}-Ar discharges using rf-compensated Langmuir probe measurements and optical emission spectroscopy (OES). As the ICP power increases, the emission intensities from plasma species, the electron density, the electron temperature, and the plasma potential exhibit sudden changes. The Ar content in the gas mixture and total gas pressure have been varied in an attempt to fully characterize the plasma parameters. With these control parameters varying, the changes of the transition threshold power and the electron energy distribution function (EEDF) are explored. In N{sub 2}-Ar and O{sub 2}-Ar discharges at low-pressures of several millitorr, the transition thresholds are observed to decrease with Ar content and pressure. It is observed that in N{sub 2}-Ar plasmas during the transition, the shape of the EEDF changes from an unusual distribution with a flat hole near the electron energy of 3 eV in the E mode to a Maxwellian distribution in the H mode. However, in O{sub 2} -Ar plasmas, the EEDFs in the E mode at low Ar contents show roughly bi-Maxwellian distributions, while the EEDFs in the H mode are observed to be nearly Maxwellian. In the E and H modes of O{sub 2}-Ar discharges, the dissociation fraction of O{sub 2} molecules is estimated using optical emission actinometry. During the E-H mode transition, the dissociation fraction of molecules is also enhanced.

  14. Dynamical Domain Tabular Collisional Radiative Equilibrium Radiation Transport Model for Argon Gas-Puff Z-Pinch Plasmas

    Microsoft Academic Search

    Y. K. Chong; J. W. Thornhill; J. P. Apruzese; J. Davis; H. D. Minor

    2005-01-01

    Summary form only given. The proper treatment of the radiation transport in the multidimensional MHD simulations of large diameter argon gas-puff Z-pinch loads is essential in understanding and predicting accurately the dynamic evolution and the radiative emission characteristics of the plasmas. The tabular collisional radiative equilibrium (TCRE) radiation transport model represents a novel approach to the realistic self-consistent treatment of

  15. Liquid crystal alignment on aC:H films by an argon plasma jet at atmospheric pressure

    Microsoft Academic Search

    H. K. Wei; C. S. Kou; K. Y. Wu; J. Hwang

    2008-01-01

    A novel liquid crystal alignment method has been successfully developed. The alignment layer was made of a hydrogenated amorphous carbon film (a-C:H). At atmospheric pressure, the surface of the film was treated by a low temperature argon plasma jet. Experimental results showed that uniform alignment of the liquid crystal (ZLI-2293) has been achieved with a pretilt angle of 2.32° in

  16. A collisional-radiative model including radiation trapping and transport phenomena for diagnostics of an inductively coupled argon plasma

    NASA Astrophysics Data System (ADS)

    Hasegawa, Tetsuya; Haraguchi, Hiroki

    The collisional-radiative model including radiation trapping and transport phenomena along with electron impact and radiative processes has been extended to the actual argon ICP, i.e. structural and inhomogeneous. The electron temperature ( Te), which is an essential plasma parameter for the collisional-radiative model, was measured from the background continuum without assuming the thermal equilibrium between the higher excited atomic levels and the ionic ground state. Observed Te at the height of 15 mm above the load coil was 8400 K, which was rather lower compared with the literature values determined from the ratio of Ar emission line and continuum in a 40-MHz ICP, while the electron number density was approx. twice larger. The calculated population number densities showed close values to LTE, because the radiation trapping, not only for the resonance lines but also for non-resonance lines, compensated for the overpopulation of low lying levels which might be caused by spontaneous emission. The transport effect of species was negligible in the normal analytical region. In the coaxial zone around 5 mm above the load coil and in the tail flame of the plasma, however, the large inflow of electrons and ions by ambipolar diffusion or convection reduced the number density of argon neutral atoms, where the argon ICP can be denned as a recombining plasma.

  17. Integrated parametric study of a hybrid-stabilized argon-water arc under subsonic, transonic and supersonic plasma flow regimes

    NASA Astrophysics Data System (ADS)

    Jeništa, J.; Takana, H.; Nishiyama, H.; Bartlová, M.; Aubrecht, V.; K?enek, P.; Hrabovský, M.; Kavka, T.; Sember, V.; Mašláni, A.

    2011-11-01

    This paper presents a numerical investigation of characteristics and processes in the worldwide unique type of thermal plasma generator with combined stabilization of arc by argon flow and water vortex, the so-called hybrid-stabilized arc. The arc has been used for spraying of ceramic or metallic particles and for pyrolysis of biomass. The net emission coefficients as well as the partial characteristics methods for radiation losses from the argon-water arc are employed. Calculations for 300-600 A with 22.5-40 standard litres per minute (slm) of argon reveal transition from a transonic plasma flow for 400 A to a supersonic one for 600 A with a maximum Mach number of 1.6 near the exit nozzle of the plasma torch. A comparison with available experimental data near the exit nozzle shows very good agreement for the radial temperature profiles. Radial velocity profiles calculated 2 mm downstream of the nozzle exit show good agreement with the profiles determined from the combination of calculation and experiment (the so-called integrated approach). A recent evaluation of the Mach number from the experimental data for 500 and 600 A confirmed the existence of the supersonic flow regime.

  18. Assessment of the roles of various inactivation agents in an argon-based direct current atmospheric pressure cold plasma jet

    SciTech Connect

    Zhang Qian; Wang Ruixue [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Sun Peng; Feng Hongqing; Liang Yongdong [College of Engineering, Peking University, Beijing 100871 (China); Zhu Weidong [Department of Applied Science and Technology, Saint Peter's College, New Jersey 07031 (United States); Becker, Kurt H. [Department of Applied Physics, Polytechnic Institute of New York University, New York 11201 (United States); Zhang Jue; Fang Jing [Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); College of Engineering, Peking University, Beijing 100871 (China)

    2012-06-15

    Three types of gases, pure argon (99.999%), argon with 2% oxygen, and argon with 2% oxygen and 10% nitrogen were used as operating gases of a direct current atmospheric pressure cold plasma jet to inactivate Staphylococcus aureus (S. aureus) suspended in a liquid. The inactivation efficacies for the plasma jets operating in the three gases decrease from Ar/O{sub 2}(2%) to Ar/O{sub 2}(2%)/N{sub 2}(10%) to pure Ar. Optical emission spectroscopy, electron spin resonance spectroscopy, high performance liquid chromatography, and atomic absorption spectrophotometry were employed to identify and monitor the reactive species in the plasma-liquid system for the three operating gases and revealed the presence of O, {sup 1}O{sub 2}, OH, NO, H{sub 2}O{sub 2}, O{sub 3}, and NO{sub 3}{sup -}/NO{sub 2}{sup -} as well as Cu{sup +}/Cu{sup 2+}. The S. aureus inactivation results indicate that atomic oxygen (O) is the key inactivation agent, while other species play a lesser role in the inactivation progress studied here.

  19. Sputtering rates of lead chalcogenide-based ternary solid solutions during inductively coupled argon plasma treatment

    NASA Astrophysics Data System (ADS)

    Zimin, S. P.; Gorlachev, E. S.; Amirov, I. I.; Zogg, H.; Abramof, E.; Rappl, P. H. O.

    2011-10-01

    In this work investigations of sputtering of monocrystalline (1 1 1)-oriented epitaxial films of semiconductor ternary solid solutions of Pb1-xSnxTe (x = 0.00-0.56), Pb1-xEuxTe (x = 0.00-0.05), Pb1-xSnxSe (x = 0.00-0.07), Pb1-xEuxSe (x = 0.00-0.16, x = 1.00), Pb1-xSnxS (x = 0.00-0.05) on Si(1 1 1) and BaF2(1 1 1) substrates in RF high-density low-pressure inductively coupled argon plasma were carried out. It is determined that sputtering rates for the studied materials retain high values typical for binary solutions PbTe, PbSe, PbS. The results indicate the interrelation of the sputtering rates of ternary compounds and of the sublimation energy of binary compounds that constitute a solid solution. The physical model of this characteristic property of lead chalcogenide-based ternary alloys based on the expansion of a classic Sigmund solid sputtering theory explaining the observed sputtering rate behavior with the alloy composition variation is proposed.

  20. [Trimming with argon plasma of self-expanding metal stents: report of 7 cases].

    PubMed

    Jury, Gastón; Amieva, Leandro; López, Fagalde Rafael; Jury, Rubén

    2014-06-01

    The use of self-expandable enteral stents for palliation of malignant stenosis may present the complication of concealing the ampulla of Vater behind the metallic mesh. Anchoring in the duodenal wall (distal or partial migration) may also be a complication of biliary metallic stents and therefore may cause difficulty in gaining access to the biliary tract. In these cases of difficult access, a fenestration on the prosthesis ( biliary or enteral) can be created to allow reaching the obstructed biliary tract by means of argon plasma (AP). Were retrospectively analysed 7 cases. Under endoscopic vision, AP was directed to filgurate and cut 6 biliary prosthesis and a duodenal stent. Fulguration and cut of biliary stent was performed in 5 cases of distal partial migration and cholangitis. In one case of obstruction caused by distal migration inside the duodenal stent light, cutting of the biliary stent was performed. A window was created in the enteral prosthesis in order to access the ampulla of Vater and place a biliary tract prosthesis. All cases were resolved successfully and without complications. We conclude that the use of AP to fulgurate and cut nitinol prosthesis was effective and presented no complications in this series. PMID:25199306

  1. Self-consistent fluid modeling and simulation on a pulsed microwave atmospheric-pressure argon plasma jet

    SciTech Connect

    Chen, Zhaoquan, E-mail: zqchen@aust.edu.cn [Faculty of Physics, St. Petersburg State University, St. Petersburg 198504 (Russian Federation); College of Electrical and Information Engineering, Anhui University of Science and Technology, Huainan, Anhui 232001 (China); Yin, Zhixiang, E-mail: zxyin66@163.com; Chen, Minggong; Hong, Lingli; Hu, Yelin; Huang, Yourui [College of Electrical and Information Engineering, Anhui University of Science and Technology, Huainan, Anhui 232001 (China); Xia, Guangqing; Liu, Minghai [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Kudryavtsev, A. A. [Faculty of Physics, St. Petersburg State University, St. Petersburg 198504 (Russian Federation)

    2014-10-21

    In present study, a pulsed lower-power microwave-driven atmospheric-pressure argon plasma jet has been introduced with the type of coaxial transmission line resonator. The plasma jet plume is with room air temperature, even can be directly touched by human body without any hot harm. In order to study ionization process of the proposed plasma jet, a self-consistent hybrid fluid model is constructed in which Maxwell's equations are solved numerically by finite-difference time-domain method and a fluid model is used to study the characteristics of argon plasma evolution. With a Guass type input power function, the spatio-temporal distributions of the electron density, the electron temperature, the electric field, and the absorbed power density have been simulated, respectively. The simulation results suggest that the peak values of the electron temperature and the electric field are synchronous with the input pulsed microwave power but the maximum quantities of the electron density and the absorbed power density are lagged to the microwave power excitation. In addition, the pulsed plasma jet excited by the local enhanced electric field of surface plasmon polaritons should be the discharge mechanism of the proposed plasma jet.

  2. Experimental investigation of argon metastable density and electron temperature in low-pressure plasma by line-ratio OES technique

    NASA Astrophysics Data System (ADS)

    Lee, Young-Kwang; Kim, Yu-Sin; Lee, Jae-Won; Hwang, Hye-Ju; Chung, Chin-Wook

    2011-11-01

    The measurement of metastable atom densities and electron temperatures are performed in inductively coupled plasma (ICP) source (13.56 MHz) combined with biased electrode (12.5 MHz), in pure argon or in mixtures of N2. The argon metastable densities and electron temperatures are derived under the different discharge conditions, i.e., E-H mode transition, rf power biasing and Ar-N2 mixtures. The observation of certain argon spectral lines (750.4, 751.5 and 811.5 nm) is made with optical emission spectroscopy (OES) at the pressure of 50 and 100 mTorr. In the same plasma conditions, rf-compensated Langmuir probe is used to measure the electron energy distribution functions (EEDFs) that provides the accurate rate coefficients to calculate the line-ratio OES method. It is found that the 1s5 metastable density was found to be the highest concentration at mode transition region but it decreases with increasing rf bias power or mixing ratio of N2. The measurements of electron temperature measured by line-ratio OES and probe confirmed that electron temperature was relatively uniform at mode transition but it increases with increasing rf bias power or mixing ratio of N2.

  3. Characterization of an inductively coupled nitrogen-argon plasma by Langmuir probe combined with optical emission spectroscopy

    SciTech Connect

    Song, M. A.; Lee, Y. W.; Chung, T. H. [Department of Physics, Dong-A University, Busan 604-714 (Korea, Republic of)

    2011-02-15

    The properties of low-pressure inductively coupled nitrogen-argon plasmas were investigated by using a Langmuir probe combined with optical emission spectroscopy (OES) under the conditions of pressures in the range of 1-30 mTorr and applied rf powers of 200-600 W. In the experiments, the argon was introduced as an actinometer and as an adding gas. The effect of the argon content in the gas mixture was examined in the range of 5%-80%. The electron energy probability function (EEPF), the electron density, and the electron temperature were obtained by using an rf-compensated Langmuir probe. The dissociation fractions were obtained from the OES actinometry. The electron temperature was also obtained by OES corona model and compared with that measured by the probe. The second positive and first negative systems of spectral bands from nitrogen molecules were analyzed to estimate the vibrational and rotational temperatures. The effects of the control parameters on the plasma parameters and dissociation fraction were investigated. While the calculated nitrogen atom density increased with power, it exhibited a maximum value near the Ar content of 30%.

  4. Characterization of an inductively coupled nitrogen-argon plasma by Langmuir probe combined with optical emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Song, M. A.; Lee, Y. W.; Chung, T. H.

    2011-02-01

    The properties of low-pressure inductively coupled nitrogen-argon plasmas were investigated by using a Langmuir probe combined with optical emission spectroscopy (OES) under the conditions of pressures in the range of 1-30 mTorr and applied rf powers of 200-600 W. In the experiments, the argon was introduced as an actinometer and as an adding gas. The effect of the argon content in the gas mixture was examined in the range of 5%-80%. The electron energy probability function (EEPF), the electron density, and the electron temperature were obtained by using an rf-compensated Langmuir probe. The dissociation fractions were obtained from the OES actinometry. The electron temperature was also obtained by OES corona model and compared with that measured by the probe. The second positive and first negative systems of spectral bands from nitrogen molecules were analyzed to estimate the vibrational and rotational temperatures. The effects of the control parameters on the plasma parameters and dissociation fraction were investigated. While the calculated nitrogen atom density increased with power, it exhibited a maximum value near the Ar content of 30%.

  5. Single-shot Thomson scattering on argon plasmas created by the Microwave Plasma Torch; evidence for a new plasma class

    Microsoft Academic Search

    J. J. A. M. van der Mullen; M. J. van de Sande; N. de Vries; BHP Broks; EI Iordanova; A. Gamero; J. Torres; A. Sola

    2007-01-01

    To determine the fine-structure size of plasmas created by a Microwave Plasma Torch (MPT), single-shot Thomson scattering (TS) measurements were performed. The aim was to find a solution for the long-standing discrepancy between experiments and Global Plasma Models (GPMs). Since these GPMs are based on the assumption that (ambipolar) diffusion is the main loss process for charged particles, the diffusion

  6. Time-dependent effects of low-temperature atmospheric-pressure argon plasma on epithelial cell attachment, viability and tight junction formation in vitro

    NASA Astrophysics Data System (ADS)

    Hoentsch, Maxi; von Woedtke, Thomas; Weltmann, Klaus-Dieter; Nebe, J. Barbara

    2012-01-01

    The application of physical plasma to living tissues is expected to promote wound healing by plasma disinfection and stimulation of tissue regeneration. However, the effects of plasma on healthy cells must be studied and understood. In our experiments we used an argon plasma jet (kINPen®09) to gain insights into time-dependent plasma effects on cell attachment, viability and tight junction formation in vitro. Murine epithelial cells mHepR1 were suspended in complete cell culture medium and were irradiated with argon plasma (direct approach) for 30, 60 and 120 s. Suspecting that physical plasma may exert its effect via the medium, cell culture medium alone was first treated with argon plasma (indirect approach) and immediately afterwards, cells were added and also cultured for 24 h. Cell morphology and vitality were verified using light microscopy and an enzyme-linked immunosorbent assay. Already after 30 s of treatment the mHepR1 cells lost their capability to adhere and the cell vitality decreased with increasing treatment time. Interestingly, the same inhibitory effect was observed in the indirect approach. Furthermore, the argon plasma-treated culture medium-induced large openings of the cell's tight junctions, were verified by the zonula occludens protein ZO-1, which we observed for the first time in confluently grown epithelial cells.

  7. Selective depletion of plasma prekallikrein or coagulation factor XII inhibits thrombosis in mice without increased risk of bleeding.

    PubMed

    Revenko, Alexey S; Gao, Dacao; Crosby, Jeff R; Bhattacharjee, Gourab; Zhao, Chenguang; May, Chris; Gailani, David; Monia, Brett P; MacLeod, A Robert

    2011-11-10

    Recent studies indicate that the plasma contact system plays an important role in thrombosis, despite being dispensable for hemostasis. For example, mice deficient in coagulation factor XII (fXII) are protected from arterial thrombosis and cerebral ischemia-reperfusion injury. We demonstrate that selective reduction of prekallikrein (PKK), another member of the contact system, using antisense oligonucleotide (ASO) technology results in an antithrombotic phenotype in mice. The effects of PKK deficiency were compared with those of fXII deficiency produced by specific ASO-mediated reduction of fXII. Mice with reduced PKK had ? 3-fold higher plasma levels of fXII, and reduced levels of fXIIa-serpin complexes, consistent with fXII being a substrate for activated PKK in vivo. PKK or fXII deficiency reduced thrombus formation in both arterial and venous thrombosis models, without an apparent effect on hemostasis. The amount of reduction of PKK and fXII required to produce an antithrombotic effect differed between venous and arterial models, suggesting that these factors may regulate thrombus formation by distinct mechanisms. Our results support the concept that fXII and PKK play important and perhaps nonredundant roles in pathogenic thrombus propagation, and highlight a novel, specific and safe pharmaceutical approach to target these contact system proteases. PMID:21821705

  8. Mitigation of carbon erosion in beryllium seeded deuterium plasma under bombardment by argon and helium ions in PISCES-B

    NASA Astrophysics Data System (ADS)

    Kreter, A.; Nishijima, D.; Baldwin, M. J.; Doerner, R. P.; Pospieszczyk, A.

    2011-10-01

    The influence of argon and helium impurities on chemical erosion of carbon by deuterium and on the mitigation of erosion by the beryllium seeding has been studied in the PISCES-B linear plasma device. Optical spectroscopy has been used to quantify the amounts of Be, Ar and He in the deuterium plasma and to monitor the reduction of the CD band as a measure of carbon chemical erosion of the fine-grain graphite target. The addition of Ar and He has not resulted in an increase of the carbon erosion rate. Moreover, the characteristic time for the Be layer formation was in agreement with the reference exposures. It can be concluded, that for the covered range of experimental parameters the addition of Ar and He to plasma does not affect the formation of the protective Be carbide layer and the associated mitigation of carbon erosion.

  9. Kinetic modeling of evolution of 3?+?1:Resonance enhanced multiphoton ionization plasma in argon at low pressures

    SciTech Connect

    Tholeti, Siva Sashank; Alexeenko, Alina A., E-mail: alexeenk@purdue.edu [School of Aeronautics and Astronautics, Purdue University, West Lafayette, Indiana 47907 (United States); Shneider, Mikhail N. [Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States)

    2014-06-15

    We present numerical kinetic modeling of generation and evolution of the plasma produced as a result of resonance enhanced multiphoton ionization (REMPI) in Argon gas. The particle-in-cell/Monte Carlo collision (PIC/MCC) simulations capture non-equilibrium effects in REMPI plasma expansion by considering the major collisional processes at the microscopic level: elastic scattering, electron impact ionization, ion charge exchange, and recombination and quenching for metastable excited atoms. The conditions in one-dimensional (1D) and two-dimensional (2D) formulations correspond to known experiments in Argon at a pressure of 5?Torr. The 1D PIC/MCC calculations are compared with the published results of local drift-diffusion model, obtained for the same conditions. It is shown that the PIC/MCC and diffusion-drift models are in qualitative and in reasonable quantitative agreement during the ambipolar expansion stage, whereas significant non-equilibrium exists during the first few 10?s of nanoseconds. 2D effects are important in the REMPI plasma expansion. The 2D PIC/MCC calculations produce significantly lower peak electron densities as compared to 1D and show a better agreement with experimentally measured microwave radiation scattering.

  10. The effect of radio-frequency self bias on ion acceleration in expanding argon plasmas in helicon sources

    NASA Astrophysics Data System (ADS)

    Wiebold, Matthew D.

    Time-averaged plasma potential differences up to ˜ 165 V over several hundred Debye lengths are observed in low pressure (pn < 1 mTorr) expanding argon plasmas in the Madison Helicon Experiment. The potential gradient leads to ion acceleration exceeding Ei ? 7 kTe in some cases. Up to 1 kW of 13.56 MHz RF power is supplied to a half-turn, double-helix antenna in the presence of a nozzle magnetic field up to 1 kG. An RPA measures the IEDF and an emissive probe measures the plasma potential. Single and double probes measure the electron density and temperature. Two distinct mode hops, the capacitive-inductive (E-H) and inductive-helicon (H-W) transitions, are identified by jumps in electron density as RF power is increased. In the capacitive mode, large fluctuations of the plasma potential (Vp--p ? 140 V, Vp--p/Vp ? 150%) exist at the RF frequency, leading to formation of a self-bias voltage. The mobile electrons can flow from the upstream region during an RF cycle whereas ions cannot, leading to an initial imbalance of flux, and the self-bias voltage builds as a result. The plasma potential in the expansion chamber is held near the floating potential for argon (Vp ? 5kTe/e). In the capacitive mode, the ion acceleration is not well described by an ambipolar relation. The accelerated population decay is consistent with that predicted by charge-exchange collisions. Grounding the upstream endplate increases the self-bias voltage compared to a floating endplate. In the inductive and helicon modes, the ion acceleration more closely follows an ambipolar relation, a result of decreased capacitive coupling due to the decreased RF skin depth. The scaling of the potential gradient with the argon flow rate, magnetic field and RF power are investigated, with the highest potential gradients observed for the lowest flow rates in the capacitive mode. The magnitude of the self-bias voltage agrees well with that predicted for RF sheaths. Use of the self-bias effect in a plasma thruster is explored, possibly for a low thrust, high specific impulse mode in a multi-mode helicon thruster. This work could also explain similar potential gradients in expanding helicon plasmas that are ascribed to double layer formation in the literature.

  11. Dentin surface treatment using a non-thermal argon plasma brush for interfacial bonding improvement in composite restoration

    PubMed Central

    Ritts, Andy Charles; Li, Hao; Yu, Qingsong; Xu, Changqi; Yao, Xiaomei; Hong, Liang; Wang, Yong

    2010-01-01

    The objective of this study is to investigate the treatment effects of non-thermal atmospheric gas plasmas on dentin surfaces for composite restoration. Extracted unerupted human third molars were used by removing the crowns and etching the exposed dentin surfaces with 35% phosphoric acid gel. The dentin surfaces were treated by using a non-thermal atmospheric argon plasma brush for various durations. The molecular changes of the dentin surfaces were analyzed using FTIR/ATR and an increase in carbonyl groups on dentin surfaces was detected with plasma treated dentin. Adper Single Bond Plus adhesive and Filtek Z250 dental composite were applied as directed. To evaluate the dentin/composite interfacial bonding, the teeth thus prepared were sectioned into micro-bars as the specimens for tensile test. Student Newman Keuls tests showed that the bonding strength of the composite restoration to peripheral dentin was significantly increased (by 64%) after 30 s plasma treatment. However, the bonding strength to plasma treated inner dentin did not show any improvement. It was found that plasma treatment of peripheral dentin surface up to 100 s gave an increase in interfacial bonding strength, while a prolong plasma treatment of dentin surfaces, e.g., 5 min treatments, showed a decrease in interfacial bonding strength. PMID:20831586

  12. Effects of heating coagulation of middle meningeal artery on plasma CGRP level and c-fos expression in migraine rat triggered by nitroglycerin.

    PubMed

    Zhu, Xiaofeng; Han, Yuechen; Xiong, Wenping; Liu, Wenwen; Lu, Sumei; Li, Jianfeng; Wang, Haibo; Fan, Zhaomin

    2011-08-01

    Current theory or hypothesis relevant to migraine indicates that trigeminovascular system plays a pivotal role in the pathophysiology of migraine. Particularly, release of neuropeptide and induction of c-fos like immunoreactivity (c-fos LI) within trigeminal nucleus caudalis neurons are regarded as activation markers of trigeminovascular system. In the present study, we set up a rat model for migraine triggered by nitroglycerin (NTG) and coagulated the middle meningeal artery by heating. Using this model, we determined the plasma calcitonin gene-related peptide (CGRP) level as well as the expression of c-fos in trigeminal nucleus caudalis of rats. We found that NTG led to markedly increase in plasma CGRP level and c-fos expression in trigeminal nucleus caudalis compared with the isotonic saline-treated group (P < 0.05). More importantly, heat coagulation of middle meningeal artery could decrease plasma CGRP level and c-fos expression in trigeminal nucleus caudalis (P < 0.05). Heat coagulation of middle meningeal artery may ameliorate sufferings of rat induced by NTG and play an important role in restraining the release of CGRP as well as the activation of neurons in trigeminal nucleus caudalis in rats following NTG infusion. PMID:21331665

  13. Thermophysical properties of carbon-argon and carbon-helium plasmas

    Microsoft Academic Search

    WeiZong Wang; MingZhe Rong; Anthony B. Murphy; Yi Wu; Joseph W. Spencer; Joseph D. Yan; Michael T. C. Fang

    2011-01-01

    The calculated values of thermodynamic and transport properties of mixtures of carbon and argon, and carbon and helium, at high temperatures are presented in this paper. The thermodynamic properties are determined by the method of Gibbs free energy minimization, using standard thermodynamic tables. The transport properties including electron diffusion coefficients, viscosity, thermal conductivity and electrical conductivity are evaluated using the

  14. Real-time analysis of metals in stack gas using argon/air inductively coupled plasma with optical emission spectrometry

    NASA Astrophysics Data System (ADS)

    Meyer, Gerhard; Seltzer, Michael D.

    1999-02-01

    The design and operation of an instrument capable of continuous, real-time detection of hazardous air pollutant metals in the effluent of boilers, incinerators, and furnaces is reported. A commercially available inductively coupled argon plasma spectrometer, modified for introduction of sample air, provides sensitivity for several metals comparable to that of EPA-approved manual methods, with an analysis result reported every 1 to 2 minutes. Achievable detection limits for the present list of hazardous air pollutant metals range from 0.1 to 20 (mu) g/dry standard cubic meter. Air is isokinetically extracted from a stack or duct and introduced into the argon plasma through an innovative sample transport interface. Data is reported after every measurement cycle and immediately archived to a control computer, where the information is available to a local area network. The entire instrument is automated, and is enclosed in a shelter that can be placed as near as possible to the stack. The measurement of sample losses in the transport line is also discussed.

  15. Determination of dissolved boron in fresh, estuarine, and geothermal waters by d.c. argon-plasma emission spectrometry

    USGS Publications Warehouse

    Ball, J.W.; Thompson, J.M.; Jenne, E.A.

    1978-01-01

    A d.c. argon-plasma emission spectrometer is used to determine dissolved boron in natural (fresh and estuarine) water samples. Concentrations ranged from 0.02 to 250 mg l-1. The emission-concentration function is linear from 0.02 to 1000 mg l-1. Achievement of a relative standard deviation of ??? 3% requires frequent restandardization to offset sensitivity changes. Dilution may be necessary to overcome high and variable electron density caused by differences in alkali-metal content and to avoid quenching of the plasma by high solute concentrations of sodium and other easily ionized elements. The proposed method was tested against a reference method and found to be more sensitive, equally or more precise and accurate, less subject to interferences, with a wider linear analytical range than the carmine method. Analyses of standard reference samples yielded results in all cases within one standard deviation of the means. ?? 1978.

  16. VOLUME 82, NUMBER 4 P H Y S I C A L R E V I E W L E T T E R S 25 JANUARY 1999 Spectroscopic Measurements of Argon Plasma Formation

    E-print Network

    Cohen, David

    Measurements of Argon Plasma Formation by a High-Intensity Lithium Ion Beam J. E. Bailey,1 H. K. Chung,2 A. L of plasma formation by a 20 nsec, 9 MeV, 20 kA cm2 Li13 ion beam injected into 2-Torr argon, conditions II, must be accounted for to achieve accu- rate predictions of the argon ionization kinetics. Light

  17. The study of a homogeneous column of argon plasma at a pressure of 0.5 torr, generated by means of the Beenakker's cavity

    NASA Astrophysics Data System (ADS)

    Epstein, Irene L.; Gavrilovi?, Marijana; Jovi?evi?, Sonja; Konjevi?, Nikola; Lebedev, Yuri A.; Tatarinov, Alexey V.

    2014-11-01

    A homogeneous column of argon plasma at a pressure of 0.5 torr, generated by means of the Beenakker cavity, has been investigated by methods of emission spectroscopy, photography and self-consistent 3D modeling in a nonlocal approximation. It is shown that the plasma column, which spreads beyond the resonator, is spatially uniform and it represents the afterglow of the microwave discharge produced inside the cavity. The simulation data of the spatial distributions of the electron energy density and concentrations of electrons, ions and argon atoms in metastable and radiating states are presented. The results of calculations are in agreement with experimental data.

  18. Ion Transport Measurements in a Multi-Dipole Argon Plasma by Broadband Laser Induced Fluorescence

    Microsoft Academic Search

    Jinlin Xie; Zhi Yu; Wandong Liu; Changxuan Yu

    2009-01-01

    Argon ion laser induced fluorescence measurements were carried out in a multipolar filament discharge with a broadband diode laser centered on 668 nm, which stimulated a transition from the metastable state in Ar(II) 3d4F7\\/2 to 4p4D05\\/2. The intensity of the induced fluorescence at 442 nm was maximized by the optimization of the discharge parameters and the laser power. From the

  19. Evaluation of bone response to synthetic bone grafting material treated with argon-based atmospheric pressure plasma.

    PubMed

    Beutel, Bryan G; Danna, Natalie R; Gangolli, Riddhi; Granato, Rodrigo; Manne, Lakshmiprada; Tovar, Nick; Coelho, Paulo G

    2014-12-01

    Bone graft materials are utilized to stimulate healing of bone defects or enhance osseointegration of implants. In order to augment these capabilities, various surface modification techniques, including atmospheric pressure plasma (APP) surface treatment, have been developed. This in vivo study sought to assess the effect of APP surface treatment on degradation and osseointegration of Synthograft™, a beta-tricalcium phosphate (?-TCP) synthetic bone graft. The experimental (APP-treated) grafts were subjected to APP treatment with argon for a period of 60s. Physicochemical characterization was performed by environmental scanning electron microscopy, surface energy (SE), and x-ray photoelectron spectroscopy analyses both before and after APP treatment. Two APP-treated and two untreated grafts were surgically implanted into four critical-size calvarial defects in each of ten New Zealand white rabbits. The defect samples were explanted after four weeks, underwent histological analysis, and the percentages of bone, soft tissue, and remaining graft material were quantified by image thresholding. Material characterization showed no differences in particle surface morphology and that the APP-treated group presented significantly higher SE along with higher amounts of the base material chemical elements on it surface. Review of defect composition showed that APP treatment did not increase bone formation or reduce the amount of soft tissue filling the defect when compared to untreated material. Histologic cross-sections demonstrated osteoblastic cell lines, osteoid deposition, and neovascularization in both groups. Ultimately, argon-based APP treatment did not enhance the osseointegration or degradation of the ?-TCP graft. Future investigations should evaluate the utility of gases other than argon to enhance osseointegration through APP treatment. PMID:25491854

  20. On the difference between breakdown and quench voltages of argon plasma and its relation to 4p-4s atomic state transitions

    NASA Astrophysics Data System (ADS)

    Forati, Ebrahim; Piltan, Shiva; Sievenpiper, Dan

    2015-02-01

    Using a relaxation oscillator circuit, breakdown (VBD) and quench (VQ) voltages of a DC discharge microplasma between two needle probes are measured. High resolution modified Paschen curves are obtained for argon microplasmas including a quench voltage curve representing the voltage at which the plasma turns off. It is shown that for a point to point microgap (e.g., the microgap between two needle probes) which describes many realistic microdevices, neither Paschen's law applies nor field emission is noticeable. Although normally VBD > VQ, it is observed that depending on environmental parameters of argon, such as pressure and the driving circuitry, plasma can exist in a different state with equal VBD and VQ. Using emission line spectroscopy, it is shown that VBD and VQ are equal if the atomic excitation by the electric field dipole moment dominantly leads to one of the argon's metastable states (4P5 in our study).

  1. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with argon

    NASA Astrophysics Data System (ADS)

    Malinina, A. A.; Malinin, A. N.

    2015-03-01

    Results are presented from studies of the optical characteristics and parameters of the plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with argon—the working medium of an exciplex gas-discharge emitter. It is established that the partial pressures of mercury dibromide vapor and argon at which the average and pulsed emission intensities in the blue—green spectral region (?max = 502 nm) reach their maximum values are 0.6 and 114.4 kPa, respectively. The electron energy distribution function, the transport characteristics, the specific power spent on the processes involving electrons, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering from the molecules and atoms of the working mixture are determined by numerical simulation, and their dependences on the reduced electric field strength are analyzed. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules for a reduced electric field of E/ N = 20 Td, at which the maximum emission intensity in the blue—green spectral region was observed in this experiment, is found to be 8.1 × 10-15 m3/s.

  2. Study of a microwave induced argon plasma sustained in a TE 101 cavity as spectrochemical emission source coupled with graphite furnace evaporation

    Microsoft Academic Search

    Jinfu Yang; Jingyu Zhang; C. Schickling; J. A. C. Broekaert

    1996-01-01

    The argon MIP sustained in a TE101 cavity has been evaluated as a spectrochemical radiation source and its analytical performance in combination with graphite furnace evaporation has been studied. A quartz discharge tube with a side arm is used, through which the sample vapour from the furnace is introduced by the carrier gas. A stable quasi-toroidal rotating plasma with a

  3. Experimental and Theoretical Analysis of Argon Plasma-Enhanced Quantum-Well Intermixing

    Microsoft Academic Search

    H. S. Djie; T. Mei; J. Arokiaraj; C. Sookdhis; S. F. Yu; L. K. Ang; X. H. Tang

    2004-01-01

    Plasma-enhanced quantum-well intermixing (QWI) has been developed for tuning the bandgap of InGaAs-InP ma- terial using an inductively coupled plasma system. The applica- tion of inductively coupled plasma enhances the interdiffusion of point defects resulting in a higher degree of intermixing. Based on a semi-empirical model of QW interdiffusion, the bandgap blue-shift with respect to the plasma exposure time and

  4. Change in Graphite Structure and Properties on Exposure to Pulsed Argon, Hydrogen, and Methane Plasma

    Microsoft Academic Search

    Academician A. V. Elyutin; I. V. Blinkov

    2004-01-01

    We studied the changes in the structure and properties of carbon materials on exposure to a capacitor discharge pulsed plasma with the following parameters: temperature, ~(50–60) × 10 3 K; pulse duration, ~100– 150 µ s. The plasma was generated using a setup consisting of a charge circuit, a capacity storage, and a plasma reactor. After the breakdown voltage (5?10

  5. Determination of rare earth elements in geological materials by inductively coupled argon plasma/atomic emission spectrometry

    USGS Publications Warehouse

    Crock, J.G.; Lichte, F.E.

    1982-01-01

    Inductively coupled argon plasma/optical emission spectrometery (ICAP/OES) is useful as a simultaneous, multielement analytical technique for the determination of trace elements in geological materials. A method for the determination of trace-level rare earth elements (REE) in geological materials using an ICAP 63-channel emission spectrometer is described. Separation and preconcentration of the REE and yttrium from a sample digest are achieved by a nitric acid gradient cation exchange and hydrochloric acid anion exchange. Precision of 1-4% relative standard deviation and comparable accuracy are demonstrated by the triplicate analysis of three splits of BCR-1 and BHVO-1. Analyses of other geological materials including coals, soils, and rocks show comparable precision and accuracy.

  6. The antibacterial activity of a microwave argon plasma jet at atmospheric pressure relies mainly on UV-C radiations

    NASA Astrophysics Data System (ADS)

    Judée, F.; Wattieaux, G.; Merbahi, N.; Mansour, M.; Castanié-Cornet, M. P.

    2014-10-01

    The main bactericidal sources produced by a microwave induced cold argon plasma jet in open air are identified and their relative proportion in the biocide efficiency of the jet is assessed on planktonic Gram-negative bacteria (wild-type strains and deletion mutants of Escherichia coli) diluted in water. In these conditions ultraviolet light (UV) most probably in the UV-C region of the electromagnetic spectrum, is responsible for 86.7 ± 3.2% of the observed bactericidal efficiency of the jet whereas hydrogen peroxide represents 9.9 ± 5.5% of it. The exposition level of the bacteria to UV-C radiations is estimated at 20 mJ cm-2 using a specific photodiode and the influence of the initial bacteria concentration on the apparent antibacterial efficiency of the jet is highlighted.

  7. Possibilities of determining non-Maxwellian EEDFs from the OES line-ratios in low-pressure capacitive and inductive plasmas containing argon and krypton

    NASA Astrophysics Data System (ADS)

    Zhu, Xi-Ming; Pu, Yi-Kang; Celik, Yusuf; Siepa, Sarah; Schüngel, Edmund; Luggenhölscher, Dirk; Czarnetzki, Uwe

    2012-04-01

    Optical emission spectroscopy (OES) is classically used to determine the electron temperature in low-temperature plasmas by assuming a Maxwellian electron energy distribution function (EEDF). However, non-Maxwellian EEDFs are often found in these plasmas. In this work, we propose an OES line-ratio method that is aimed at obtaining non-Maxwellian EEDFs, with a collisional-radiative model of argon and krypton. When applied for both a capacitively coupled plasma and an inductively coupled plasma, this method provides satisfactory results compared with those measured using a Langmuir probe.

  8. Time-resolved RF-driven probe measurements of the plasma parameters in a pulsed RF argon discharge

    NASA Astrophysics Data System (ADS)

    Voronin, S.; Alexander, M.; Bradley, J. W.

    2004-12-01

    This paper describes a three-harmonic active probe compensation technique, developed for obtaining time-resolved plasma parameter measurements in pulsed, low-pressure, RF discharges. Using a sample-and-hold circuit, the amplitude and phase of the compensation signals fed to the probe tip are tuned so that at each time point of the measurement, a maximum in the probe floating potential is achieved. The technique allows the accurate determination of the plasma parameters in transient phases of the discharge pulse (when the RF exciting voltage ramps up between 'off' and 'on' phases), not possible when the feedback signals are tuned for continuous wave (CW) operation. Comparison between this point-wise technique and CW tuning of the compensation signals has been carried out in a 1.3 Pa pressure argon discharge pulsed at frequencies between 200 and 2000 Hz. With tuning made in CW operation, the floating potentials are underestimated by about 10 V at the beginning of a pulse, while the electron temperature and plasma density are overestimated by a factor of 2, compared to the point-wise measurements. In the quiescent phases of the pulse (~100 µs after initiation), however, the two methods agree well.

  9. Influence of Electron and Excited States Densities on the Electron Energy Distribution Function of Argon Microwave Plasmas

    Microsoft Academic Search

    A. Yanguas-Gil; J. Cotrino; L. L. Alves

    2004-01-01

    A new set of electron cross-sections for argon has been compiled from a review of former sets and by using results published up to date (2004). The new set proposed has been tested by comparing calculated argon transport coefficients and swarm parameters with experimental values available, and has been used to develop a 32 level collisional-radiative model for argon. This

  10. Enhancement of injection and acceleration of electrons in a laser wakefield accelerator by using an argon-doped hydrogen gas jet and optically preformed plasma waveguide

    SciTech Connect

    Ho, Y.-C.; Hung, T.-S.; Chen, S.-Y.; Chou, M.-C. [Department of Physics, National Central University, Jhong-Li 320, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Yen, C.-P.; Wang, J. [Department of Physics, National Central University, Jhong-Li 320, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Chu, H.-H. [Department of Physics, National Central University, Jhong-Li 320, Taiwan (China); Lin, J.-Y. [Department of Physics, National Chung Cheng University, Chia-Yi 621, Taiwan (China)

    2011-06-15

    A systematic experimental study on injection of electrons in a gas-jet-based laser wakefield accelerator via ionization of dopant was conducted. The pump-pulse threshold energy for producing a quasi-monoenergetic electron beam was significantly reduced by doping the hydrogen gas jet with argon atoms, resulting in a much better spatial contrast of the electron beam. Furthermore, laser wakefield electron acceleration in an optically preformed plasma waveguide based on the axicon-ignitor-heater scheme was achieved. It was found that doping with argon atoms can also lower the pump-pulse threshold energy in this experimental configuration.

  11. Numerical Simulation of Flow in the Chamber of the Water-Argon Plasma Generator

    NASA Astrophysics Data System (ADS)

    Hlbo?an, Peter; Varchola, Michal; Knížat, Branislav; Mlkvik, Marek; Olšiak, Róbert

    2012-12-01

    The paper describes the CFD simulation of the flow of gas and plasma in a plasma generator with a hybrid stabilization of the electric arc. The momentum equations of the model also take Lorentz forces into account. In the energy equation, Joule heat is introduced as an energy source. The introduction of boundary conditions is also explained, as along with plasma transport properties and a method of solution. The paper presents selected results of pressure and velocity fields in the chamber of the plasma generator.

  12. Electron properties and air mixing in radio frequency driven argon plasma jets at atmospheric pressure

    SciTech Connect

    Gessel, Bram van; Bruggeman, Peter [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)] [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Brandenburg, Ronny [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands) [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Leibniz Institute for Plasma Science and Technology (INP Greifswald), Felix-Hausdorff-Str. 2, D-17489 Greifswald (Germany)

    2013-08-05

    A time modulated radio frequency (RF) plasma jet operated with an Ar mixture is investigated by measuring the electron density and electron temperature using Thomson scattering. The measurements have been performed spatially resolved for two different electrode configurations and as a function of the plasma dissipated power and air concentration admixed to the Ar. Time resolved measurements of electron densities and temperatures during the RF cycle and after plasma power switch-off are presented. Furthermore, the influence of the plasma on the air entrainment into the effluent is studied using Raman scattering.

  13. Probe diagnostics of argon-oxygen-tetramethyltin capacitively coupled plasmas for the deposition of tin oxide thin films

    SciTech Connect

    Pulpytel, J.; Morscheidt, W.; Arefi-Khonsari, F. [Laboratoire de Genie des procedes Plasmas, Ecole Nationale Superieure de Chimie Paris, Universite Pierre et Marie Curie, Paris 6 (France)

    2007-04-01

    Langmuir probe measurements in nondepositing and depositing rf capacitively coupled (CCP) plasmas are briefly reviewed and compared to the results obtained in our rf system used for the deposition of tin oxide (SnO{sub 2}) thin films from argon-oxygen-tetamethyltin [Sn(CH{sub 3}){sub 4}] plasmas. Typically in our experimental conditions for tin oxide deposition, values of kT{sub eff}= 1.2-1.5 eV and n{sub e}=3-5x10{sup 9} cm{sup -3} were measured. These values are consistent with those generally reported in other depositing discharges. The shape of the electron energy probability function (EEPF), obtained from the Druyvesteyn procedure, was discussed too. As a consequence of the two electron heating mechanisms in capacitively coupled discharges, that is, ohmic and stochastic heating, the electrons have a bi-Maxwellian EEPF at low pressure (in the range of 10-100 mTorr). Moreover, a deep 'hole' appears in the EEPF at the energy which could correspond to the resonant peak of the vibrational excitation cross section of some molecules which can be present in the discharge, such as N{sub 2}, CH{sub 4}, or CO.

  14. Numerical simulation study on fluid dynamics of plasma window using argon

    SciTech Connect

    Huang, S.; Zhu, K.; Shi, B. L.; Lu, Y. R. [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China)] [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Hershcovitch, A. [Brookhaven National Laboratory, New York 11973-5000 (United States)] [Brookhaven National Laboratory, New York 11973-5000 (United States); Yang, L.; Zhang, X. Y.; Wei, G. D. [Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000 (China)] [Institute of Modern Physics, Chinese Academy of Science, Lanzhou 730000 (China)

    2013-07-15

    In this paper, a numerical 2D FLUENT-based magneto-hydrodynamic model has been developed to investigate the arc and flow field of plasma window, which is used as a windowless vacuum sealing device. The gas inlet, arc creation-developing and plasma expansion segments are all incorporated together in the integral model. An axis-symmetry cathode structure (hollow cathode) is used in the model. Current distribution of the arc is presented and discussed. The temperature, velocity, and pressure field are presented to show the physical mechanisms for the high pressure gap within the plasma window. Flow acceleration and viscosity effect are concluded as the main reasons for the pressure drop. The result for the pressure distribution in the cylindrical tube section has a good agreement with the analytical model. The validation for the sealing ability of plasma window is verified.

  15. Argon plasma treatment on Cu surface for Cu bonding in 3D integration and their characteristics

    NASA Astrophysics Data System (ADS)

    Park, Manseok; Baek, Soojung; Kim, Sungdong; Kim, Sarah Eunkyung

    2015-01-01

    3D integration enhances RC delay mitigation, improves inter-die bandwidth, and has routing advantages for the next generation integrated circuit technology. To realize the advantages of 3D integration, metallic bonding between different dies or wafers is necessary. So, Cu-to-Cu metallic bonding is, without doubt, a key process needed for 3D integration. In this study, Ar plasma treatment on the Cu surface for Cu thermo-compression bonding temperature less than 400 °C was investigated. Ar plasma treatment on the Cu thin film was performed using a conventional DC sputtering technique. The effect of Cu surface modified by Ar plasma was studied for Cu-to-Cu bonding. Also, the influence of Ar plasma treatment on the Cu surface was evaluated structurally and electrically.

  16. Two-dimensional spatially resolved excitation and rotational temperatures as well as electron number density measurements in capacitively coupled microwave plasmas using argon, nitrogen and air as working gases by spectroscopic methods

    Microsoft Academic Search

    N. H. Bings; M. Olschewski; J. A. C. Broekaert

    1997-01-01

    Two-dimensional spatially resolved mappings of excitation temperatures, rotational temperatures and electron number densities have been made for capacitively coupled microwave plasmas using argon, nitrogen and air as working gases. The influence of additions of hydrogen to the working gases on the temperature and electron number density profiles in the case of the argon- and nitrogen-CMP is described and found to

  17. Equations of state, transport properties, and compositions of argon plasma: Combination of self-consistent fluid variation theory and linear response theory

    NASA Astrophysics Data System (ADS)

    Quan, W. L.; Chen, Q. F.; Fu, Z. J.; Sun, X. W.; Zheng, J.; Gu, Y. J.

    2015-02-01

    A consistent theoretical model that can be applied in a wide range of densities and temperatures is necessary for understanding the variation of a material's properties during compression and heating. Taking argon as an example, we show that the combination of self-consistent fluid variational theory and linear response theory is a promising route for studying warm dense matter. Following this route, the compositions, equations of state, and transport properties of argon plasma are calculated in a wide range of densities (0.001 -20 g /c m3) and temperatures (5 -100 kK ) . The obtained equations of state and electrical conductivities are found in good agreement with available experimental data. The plasma phase transition of argon is observed at temperatures below 30 kK and density about 2 -6 g /c m3 . The minimum density for the metallization of argon is found to be about 5.8 g /c m3 , occurring at 30 -40 kK . The effects of many-particle correlations and dynamic screening on the electrical conductivity are also discussed through the effective potentials.

  18. The Role of Spraying Parameters and Inert Gas Shrouding in Hybrid Water-Argon Plasma Spraying of Tungsten and Copper for Nuclear Fusion Applications

    NASA Astrophysics Data System (ADS)

    Mat?jí?ek, J.; Kavka, T.; Bertolissi, G.; Ctibor, P.; Vilémová, M.; Mušálek, R.; Nevrlá, B.

    2013-06-01

    Tungsten-based coatings have potential application in the plasma-facing components in future nuclear fusion reactors. By the combination of refractory tungsten with highly thermal conducting copper, or steel as a construction material, functionally graded coatings can be easily obtained by plasma spraying, and may result in the development of a material with favorable properties. During plasma spraying of these materials in the open atmosphere, oxidation is an important issue, which could have adverse effects on their properties. Among the means to control it is the application of inert gas shrouding, which forms the subject of this study and represents a lower-cost alternative to vacuum or low-pressure plasma spraying, potentially applicable also for spraying of large surfaces or spacious components. It is a continuation of recent studies focused on the effects of various parameters of the hybrid water-argon torch on the in-flight behavior of copper and tungsten powders and the resultant coatings. In the current study, argon shrouding with various configurations of the shroud was applied. The effects of torch parameters, such as power and argon flow rate, and powder morphology were also investigated. Their influence on the particle in-flight behavior as well as the structure, composition and properties of the coatings were quantified. With the help of auxiliary calculations, the mass changes of the powder particles, associated with oxidation and evaporation, were assessed.

  19. Attenuation of wall disturbances in an electron cyclotron resonance oxygen–argon plasma using real time control

    SciTech Connect

    Keville, Bernard, E-mail: bernard.keville@dcu.ie; Gaman, Cezar; Turner, Miles M. [National Centre for Plasma Science and Technology (NCPST), Research and Engineering Building, Dublin City University, Glasnevin, Dublin 9, Ireland and School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Zhang, Yang; Daniels, Stephen [National Centre for Plasma Science and Technology (NCPST), Research and Engineering Building, Dublin City University, Glasnevin, Dublin 9, Ireland and School of Electronic Engineering, Dublin City University, Glasnevin, Dublin 9 (Ireland); Holohan, Anthony M. [School of Electronic Engineering, Dublin City University, Glasnevin, Dublin 9 (Ireland)

    2014-07-01

    Present practice in plasma-assisted semiconductor manufacturing specifies recipes in terms of inputs such as gas flow rates, power and pressure. However, ostensibly identical chambers running identical recipes may produce very different results. Extensive chamber matching, i.e., initial iterative, empirical tuning of the process recipe, which entails time-consuming, ex situ statistical analysis of process metrics such as etch depth, uniformity, anisotropy and selectivity, is required to ensure acceptable results. Once matched, chambers are run open loop and are thus sensitive to disturbances such as actuator drift, wall seasoning and substrate loading, which may impact negatively on process reproducibility. An alternative approach, which may obviate the need for chamber matching and reduce the sensitivity of process metrics to exogenous disturbances, would be to specify a recipe in terms of quantities such as active species densities, and to regulate these in real time by adjusting the inputs with a suitable control algorithm. In this work, real time control of an electron cyclotron resonance O{sub 2}/Ar plasma used for photoresist ashing has been implemented. The design of elementary, model-based algorithms for the control of the argon 750 and oxygen 844 line intensities measured by optical emission spectroscopy is described. Fluorination of the chamber walls by means of an SF{sub 6} plasma prior to ashing inhibits wall recombination of oxygen radicals resulting in an approximately 20% increase in ash rate in the open loop case. However, closed loop control almost completely attenuates the effect of fluorination, thus demonstrating the efficacy of the control algorithms in ensuring a reproducible ash rate in the face of a wall disturbance.

  20. Shock-wave propagation in the plasma of a transverse glow discharge in argon

    SciTech Connect

    Basargin, I.V.; Mishin, G.I.

    1985-02-01

    Shock waves traveling perpendicularly to a glow discharge in an Ar plasma and Ar with no plasma were observed experimentally to examine the dissipation of shock wave energy. A piezoelectric gage attached to a quartz rod furnished the pressure pulse data by which the shock velocities could be monitored at two points in the ambient medium. The shock wave propagated almost three times as fast in the plasma. No connection was found between the speed-up of a shock and decreases in the shock wave amplitude. A correlation was found between the radial change in the shock velocity and the radial electron temperature profile. It is concluded that ion acoustic waves forming ahead of the shock induce an acceleration of the neutral particles and thereby an increase in the velocity of the shock wave. 7 references.

  1. Influence of the excited states on the electron-energy distribution function in low-pressure microwave argon plasmas

    Microsoft Academic Search

    A. Yanguas-Gil; J. Cotrino; A. R. González-Elipe

    2005-01-01

    In this work the influence of the excited states on the electron-energy distribution function has been determined for an argon microwave discharge at low pressure. A collisional-radiative model of argon has been developed taking into account the most recent experimental and theoretical values of argon-electron-impact excitation cross sections. The model has been solved along with the electron Boltzmann equation in

  2. Optical emission measurements of electron energy distributions in low-pressure argon inductively coupled plasmas

    NASA Astrophysics Data System (ADS)

    Boffard, John B.; Jung, R. O.; Lin, Chun C.; Wendt, A. E.

    2010-12-01

    Optical modeling of emissions from low-temperature plasmas provides a non-invasive technique to measure the electron energy distribution function (EEDF) of the plasma. While many models assume the EEDF has a Maxwell-Boltzmann distribution, the EEDFs of numerous plasma systems deviate significantly from the Maxwellian form. In this paper, we present an optical emission model for the Ar(3p54p ? 3p54s) emission array which is capable of capturing details of non-Maxwellian distributions. Our model combines previously measured electron-impact excitation cross sections with Ar(3p54s) number density measurements and emission spectra. The model also includes corrections for radiation trapping of the Ar(3p54p ? 3p54s) emission lines. Results obtained with this optical technique are compared with corresponding Langmuir probe measurements of the EEDF for Ar and Ar/N2 inductively coupled plasma systems operating under a wide variety of source conditions (1-25 mTorr, 20-1000 W, %N2 admixture). Both the optical emission method and probe measurements indicate the EEDF shapes are Maxwellian for low electron energies, but with depleted high energy tails.

  3. The effect of helium impurity addition on current sheath speed in argon-operated plasma focus using a tridimensional magnetic probe

    NASA Astrophysics Data System (ADS)

    Panahi, N.; Mohammadi, M. A.; Hedyeh, S.; Rawat, R. S.; Rawat

    2013-10-01

    Using the tridimensional magnetic probe, the current sheath velocity at 0.25 Torr is studied in Sahand, a Filippov-type plasma focus facility. The current sheath velocity in argon-filled plasma focus with different percentages of helium impurity at different operating voltages was studied. The highest average current sheath velocity of 12.26 +/- 1.51 cm ?s-1 at the top of the anode in the axial phase was achieved at 17 kV. Minimum average current sheath velocity is 5.24 +/- 1.18 cm ?s-1 at 12 kV with 80% argon + 20% helium as a working gas. The full width at half-maximum of peaks of the magnetic probe was found to be inversely related to the current sheath velocity, i.e. smaller at higher voltages for different impurity and decreased with increasing of impurity.

  4. Absorption spectroscopy measurements of argon metastable and resonant atom density in atmospheric pressure Ar-He surface-wave plasmas using a low pressure lamp

    NASA Astrophysics Data System (ADS)

    Muñoz, J.; Margot, J.; Calzada, M. D.

    2012-01-01

    The densities of metastable and resonant atom were measured in atmospheric pressure Ar-He surface-wave plasmas. Measurements were performed using an absorption spectroscopy method taking into account the Voigt profiles of the plasma lines. The density values of the argon 3P2, 3P0 (metastable atoms) and 3P1 (resonant atoms) levels measured in pure argon discharges are in good agreement with those reported in the literature. A drastic decrease of metastable and resonant densities is observed when introducing helium in amounts as low as 2%. The influence of electron density and gas temperature on the population mechanisms (direct electron excitation from the ground state and dissociative recombination) of metastable and resonant atoms is discussed using a simplified theoretical model.

  5. Dynamics of plasma expansion and shockwave formation in femtosecond laser-ablated aluminum plumes in argon gas at atmospheric pressures

    SciTech Connect

    Miloshevsky, Alexander; Harilal, Sivanandan S.; Miloshevsky, Gennady, E-mail: gennady@purdue.edu; Hassanein, Ahmed [Center for Materials Under Extreme Environment, and School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, and School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2014-04-15

    Plasma expansion with shockwave formation during laser ablation of materials in a background gasses is a complex process. The spatial and temporal evolution of pressure, temperature, density, and velocity fields is needed for its complete understanding. We have studied the expansion of femtosecond (fs) laser-ablated aluminum (Al) plumes in Argon (Ar) gas at 0.5 and 1 atmosphere (atm). The expansion of the plume is investigated experimentally using shadowgraphy and fast-gated imaging. The computational fluid dynamics (CFD) modeling is also carried out. The position of the shock front measured by shadowgraphy and fast-gated imaging is then compared to that obtained from the CFD modeling. The results from the three methods are found to be in good agreement, especially during the initial stage of plasma expansion. The computed time- and space-resolved fields of gas-dynamic parameters have provided valuable insights into the dynamics of plasma expansion and shockwave formation in fs-pulse ablated Al plumes in Ar gas at 0.5 and 1?atm. These results are compared to our previous data on nanosecond (ns) laser ablation of Al [S. S. Harilal et al., Phys. Plasmas 19, 083504 (2012)]. It is observed that both fs and ns plumes acquire a nearly spherical shape at the end of expansion in Ar gas at 1?atm. However, due to significantly lower pulse energy of the fs laser (5 mJ) compared to pulse energy of the ns laser (100 mJ) used in our studies, the values of pressure, temperature, mass density, and velocity are found to be smaller in the fs laser plume, and their time evolution occurs much faster on the same time scale. The oscillatory shock waves clearly visible in the ns plume are not observed in the internal region of the fs plume. These experimental and computational results provide a quantitative understanding of plasma expansion and shockwave formation in fs-pulse and ns-pulse laser ablated Al plumes in an ambient gas at atmospheric pressures.

  6. Reduction of Fresh Frozen Plasma Requirements by Perioperative Point-of-Care Coagulation Management with Early Calculated Goal-Directed Therapy

    PubMed Central

    Görlinger, Klaus; Fries, Dietmar; Dirkmann, Daniel; Weber, Christian F.; Hanke, Alexander A.; Schöchl, Herbert

    2012-01-01

    Background Massive bleeding and transfusion of packed red blood cells (PRBC), fresh frozen plasma (FFP) and platelets are associated with increased morbidity, mortality and costs. Patients and Methods We analysed the transfusion requirements after implementation of point-of-care (POC) coagulation management algorithms based on early, calculated, goal-directed therapy with fibrinogen concentrate and prothrombin complex concentrate (PCC) in different perioperative settings (trauma surgery, visceral and transplant surgery (VTS), cardiovascular surgery (CVS) and general and surgical intensive care medicine) at 3 different hospitals (AUVA Trauma Centre Salzburg, University Hospital Innsbruck and University Hospital Essen) in 2 different countries (Austria and Germany). Results In all institutions, the implementation of POC coagulation management algorithms was associated with a reduction in the transfusion requirements for FFP by about 90% (Salzburg 94%, Innsbruck 88% and Essen 93%). Furthermore, PRBC transfusion was reduced by 8.4–62%. The incidence of intraoperative massive transfusion (?10 U PRBC) could be more than halved in VTS and CVS (2.56 vs. 0.88%; p < 0.0001 and 2.50 vs. 1.06%; p = 0.0007, respectively). Platelet transfusion could be reduced by 21–72%, except in CVS where it increased by 115% due to a 5-fold increase in patients with dual antiplatelet therapy (2.7 vs. 13.7%; p < 0.0001). Conclusions The implementation of perioperative POC coagulation management algorithms based on early, calculated, goal-directed therapy with fibrinogen concentrate and PCC is associated with a reduction in the transfusion requirements for FFP, PRBC and platelets as well as with a reduced incidence of massive transfusion. Thus, the limited blood resources can be used more efficiently. PMID:22670128

  7. Silicon nitride etching performance of CH2F2 plasma diluted with argon or krypton

    NASA Astrophysics Data System (ADS)

    Kondo, Yusuke; Ishikawa, Kenji; Hayashi, Toshio; Miyawaki, Yudai; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru

    2015-04-01

    Etching rates of silicon nitrides (SiN), SiO2, and poly-Si films for CH2F2 plasmas diluted with rare gases are presented by comparing the effects of flow rates of CH2F2 and dilution gases (Ar and Kr). The SiO2 etching rate was considered to be controlled by ion fluxes of the incident CHF2+ and CH2F+ under the conditions for the selective etching of SiO2 and SiN over poly-Si. Interestingly, the SiN etching rate was considerably affected by the dilution gas used. The SiN surface reaction was promoted by F-rich chemistry in the Ar-diluted CH2F2 plasma with a relatively high density of F atoms.

  8. Diamondoid synthesis in atmospheric pressure adamantane-argon-methane-hydrogen mixtures using a continuous flow plasma microreactor

    NASA Astrophysics Data System (ADS)

    Stauss, Sven; Ishii, Chikako; Pai, David Z.; Urabe, Keiichiro; Terashima, Kazuo

    2014-06-01

    Due to their small size, low-power consumption and potential for integration with other devices, microplasmas have been used increasingly for the synthesis of nanomaterials. Here, we have investigated the possibility of using dielectric barrier discharges generated in continuous flow glass microreactors for the synthesis of diamondoids, at temperatures of 300 and 320 K, and applied voltages of 3.2-4.3 kVp-p, at a frequency of 10 kHz. The microplasmas were generated in gas mixtures containing argon, methane, hydrogen and adamantane, which was used as a precursor and seed. The plasmas were monitored by optical emission spectroscopy measurements and the synthesized products were characterized by gas chromatography—mass spectrometry (GC-MS). Depending on the gas composition, the optical emission spectra contained CH and C2 bands of varying intensities. The GC-MS measurements revealed that diamantane can be synthesized by microplasmas generated at atmospheric pressure, and that the yields highly depend on the gas composition and the presence of carbon sources.

  9. Effects of argon laser on in vitro aggregation of platelets in platelet rich plasma and whole blood

    SciTech Connect

    Doerger, P.T.; Glueck, H.I.; McGill, M.

    1988-06-01

    The effects of an Argon laser on platelet aggregation were studied, since platelets may be exposed to laser energy when used intravascularly. Various preparations of platelets in platelet rich plasma (PRP) and whole blood, with or without aspirin, were tested with the aggregating agents ADP, collagen, thrombin, and epinephrine. Simultaneous release of ATP was also measured in PRP. At relatively low levels of irradiation, platelet aggregation was potentiated. Enhancement was evidenced by an increase in percent aggregation, earlier onset of the reaction, and reduction in the amount of aggregating agent required. In PRP, the mechanism of laser potentiation appeared to be the release of endogenous ATP from platelets. At relatively high levels of irradiation, platelets were destroyed and aggregation abolished. In whole blood, the mechanism was somewhat more complicated since release of ATP occurred from RBCs as well as platelets. Spontaneous aggregation following laser treatment occurred in isolated instances in PRP and in every trial in whole blood preparations. Aspirin ingestion inhibited the laser's effects in PRP but not in whole blood. These results may have important clinical implications for laser angioplasty, and the potentiated aggregation response may prove useful in laboratory studies of platelet function.

  10. Angular distribution of energetic argon ions emitted by a 90 kJ Filippov-type plasma focus

    NASA Astrophysics Data System (ADS)

    Pestehe, S. J.; Mohammadnejad, M.

    2015-02-01

    Characteristics of the energetic argon ions emitted by a 90 kJ Filippov-type plasma focus are studied by employing an array of Faraday cups. The Faraday cups are designed to minimize the secondary electron emission effects on their response. Angular distribution of the ions is measured, and the results indicate a highly anisotropic emission with a dip at the device axis and a local maximum at the angle of 7° with respect to the axis. It has been argued that this kind of anisotropic emission may be related to the surfatron acceleration mechanism and shown that this behavior is independent of the working gas pressure. It has been also demonstrated that this mechanism is responsible for the generation of MeV ions. Measuring the total ion number at different working gas pressures gives an optimum pressure of 0.3 Torr. In addition, the energy spectrum of ions is measured by taking into account of the ambient gas effects on the energy and charge of the ions. The current neutralization effect of electrons trapped in the ion beam as well as the effect of conducting boundaries surrounding the beam, on the detected signals are investigated.

  11. Modelling on dynamics properties of a stationary argon cascaded arc plasma flows

    SciTech Connect

    Wei, G. D.; Qi, X.; Yang, L., E-mail: lyang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2014-03-15

    The gas dynamics properties of a stationary arc plasma flows are studied through the numerical simulations. A two dimensional axis-symmetric turbulent magneto-hydrodynamic plasma model is developed with the commercial code ANSYS FLUENT. The reliable ?-? model is used to account for turbulence. In this paper, the plasma is assumed to be a fluid following Navier–Stokes equations, respecting local thermodynamic equilibrium, and described by only one temperature. Distributions of the pressure, velocity, temperature, density, and electric potential inside of thus cascaded arc are obtained for an arc current density of 10{sup 6}?A/m{sup 2}. The pressure inside the arc varies from 10{sup 5}?Pa to 100?Pa. The temperature at the arc axis can reach as high as 13?600?K. The electric potential drops uniformly along the axis with a magnitude of 160?V. In addition, distributions of the sonic velocity and Mach number are shown to describe supersonic behavior of thus cascaded arc, which have a good agreement with the analytical formula.

  12. Modelling on dynamics properties of a stationary argon cascaded arc plasma flows

    NASA Astrophysics Data System (ADS)

    Wei, G. D.; Qi, X.; Yang, L.

    2014-03-01

    The gas dynamics properties of a stationary arc plasma flows are studied through the numerical simulations. A two dimensional axis-symmetric turbulent magneto-hydrodynamic plasma model is developed with the commercial code ANSYS FLUENT. The reliable ?-? model is used to account for turbulence. In this paper, the plasma is assumed to be a fluid following Navier-Stokes equations, respecting local thermodynamic equilibrium, and described by only one temperature. Distributions of the pressure, velocity, temperature, density, and electric potential inside of thus cascaded arc are obtained for an arc current density of 106 A/m2. The pressure inside the arc varies from 105 Pa to 100 Pa. The temperature at the arc axis can reach as high as 13 600 K. The electric potential drops uniformly along the axis with a magnitude of 160 V. In addition, distributions of the sonic velocity and Mach number are shown to describe supersonic behavior of thus cascaded arc, which have a good agreement with the analytical formula.

  13. Expansion Dynamics of Ultrafast Laser Produced Plasmas in the Presence of Ambient Argon

    SciTech Connect

    Diwakar, P. K.; Harilal, Sivanandan S.; Hassanein, A.; Phillips, Mark C.

    2014-10-07

    In this paper, we report the emission features of fs laser ablated brass plasma plumes at various Ar background pressure levels ranging from vacuum to atmospheric conditions. Spectrally integrated 2D-imaging of plasma self-emission showed several interesting features at various pressure levels which consists of plume morphological changes, increase in persistence, confinement, and internal structures. Spatially resolved wavelength dispersed images of the plume were recorded for characterizing the spectral features at various pressure levels and also used for obtaining spatial distribution of Cu I and Zn I species in the plume, signal to noise ratios and fundamental parameters of the plasma; viz. temperature and density. The spatial evolution of excitation temperature and density showed significant changes at various ambient pressure levels and these results were correlated to morphological changes seen in the plume images. Optimum signal to background ratios for emission lines were observed in the moderate pressure range (~ 1-10 Torr). Optical time-of-flight profiles were used to study time evolution of various species in the plume and noticed oscillations at intermediate pressure levels. Possible mechanisms for observed changes in plume shape, optical emission intensity, and dual peak structures in time-of-flight profiles were discussed.

  14. Systems Biology of Coagulation

    PubMed Central

    Diamond, Scott L.

    2013-01-01

    Accurate computer simulation of blood function can inform drug target selection, patient-specific dosing, clinical trial design, biomedical device design, as well as the scoring of patient-specific disease risk and severity. These large-scale simulations rely on hundreds of independently measured physical parameters and kinetic rate constants. However, the models can be validated against large scale, patient-specific laboratory measurements. By validation with high dimensional data, modelling becomes a powerful tool to predict clinically complex scenarios. Currently, it is possible to accurately predict the clotting rate of plasma or blood in a tube as it is activated with a dose of tissue factor, even as numerous coagulation factors are altered by exogenous attenuation or potentiation. Similarly, the dynamics of platelet activation, as indicated by calcium mobilisation or inside-out signalling, can now be numerically simulated with accuracy in cases where platelets are exposed to combinations of agonists. Multiscale models have emerged to combine platelet function and coagulation kinetics into complete physics-based descriptions of thrombosis under flow. Blood flow controls platelet fluxes, delivery and removal of coagulation factors, adhesive bonding, and von Willebrand factor conformation. The field of Blood Systems Biology has now reached a stage that anticipates the inclusion of contact, complement, and fibrinolytic pathways along with models of neutrophil and endothelial activation. Along with “-omics” data sets, such advanced models seek to predict the multifactorial range of healthy responses and diverse bleeding and clotting scenarios, ultimately to understand and improve patient outcomes. PMID:23809126

  15. Argon/UF6 plasma experiments: UF6 regeneration and product analysis

    NASA Technical Reports Server (NTRS)

    Roman, W. C.

    1980-01-01

    An experimental and analytical investigation was conducted to aid in developing some of the technology necessary for designing a self-critical fissioning uranium plasma core reactors (PCR). This technology is applicable to gaseous uranium hexafluoride nuclear-pumped laser systems. The principal equipment used included 1.2 MW RF induction heater, a d.c. plasma torch, a uranium tetrafluoride feeder system, and batch-type fluorine/UF6 regeneration systems. Overall objectives were to continue to develop and test materials and handling techniques suitable for use with high-temperature, high-pressure, gaseous UF6; and to continue development of complementary diagnostic instrumentation and measurement techniques to characterize the effluent exhaust gases and residue deposited on the test chamber and exhaust system components. Specific objectives include: a development of a batch-type UF6 regeneration system employing pure high-temperature fluorine; development of a ruggedized time-of-flight mass spectrometer and associated data acquisition system capable of making on-line concentration measurements of the volatile effluent exhaust gas species in a high RF environment and corrosive environment of UF6 and related halide compounds.

  16. Friction and wear properties of smooth diamond films grown in fullerene-argon plasmas

    SciTech Connect

    Erdemir, A.; Fenske, G.R.; Bindal, C.; Zuiker, C.; Krauss, A.R.; Gruen, D.M.

    1995-08-01

    In this study, we describe the growth mechanism and the ultralow friction and wear properties of smooth (20-50 nm rms) diamond films grown in a microwave plasma consisting of Ar and fullerene (the carbon source). The sliding friction coefficients of these films against Si{sub 3}N{sub 4} balls are 0.04 and 0.1 in dry N{sub 2} and air, which are comparable to that of natural diamond sliding against the same pin material, but is lower by factors of 5 to 10 than that afforded by rough diamond films grown in conventional H{sub 2}-CH{sub 4} plasmas. Furthermore, the smooth diamond films produced in this work afforded wear rates to Si{sub 3}N{sub 4} balls that were two to three orders of magnitude lower than those of H{sub 2}-CH{sub 4} grown films. Mechanistically, the ultralow friction and wear properties of the fullerene-derived diamond films correlate well with their initially smooth surface finish and their ability to polish even further during sliding. The wear tracks reach an ultrasmooth (3-6 nm rms) surface finish that results in very little abrasion and ploughing. The nanocrystalline microstructure and exceptionally pure sp{sup 3} bonding in these smooth diamond films were verified by numerous surface and structure analytical methods, including x-ray diffraction, high-resolution AF-S, EELS, NEXAFS, SEM, and TEM. An AFM instrument was used to characterize the topography of the films and rubbing surfaces.

  17. Successful Treatment of Discoid Lupus erythematosus with Argon Laser

    Microsoft Academic Search

    Annegret Kuhn; Petra Maria Becker-Wegerich; Thomas Ruzicka; Percy Lehmann

    2000-01-01

    Vascular lesions with telangiectasias on visible areas, such as the face, are common in discoid lupus erythematosus (DLE); however, an efficient management of these skin lesions can sometimes be difficult. Since argon laser light is able to specifically coagulate vascular structures, it has been used in the treatment of various vascular skin malformations. Therefore, we addressed the issue whether argon

  18. On the difference between breakdown and quench voltages of argon plasma and its relation to $4p-4s$ atomic state transitions

    E-print Network

    Forati, Ebrahim; Sievenpiper, Dan

    2014-01-01

    Using a relaxation oscillator circuit, breakdown ($V_{\\mathrm{BD}}$) and quench ($V_{\\mathrm{Q}}$) voltages of a DC discharge microplasma between two needle probes are measured. High resolution modified Paschen curves are obtained for argon microplasmas including a quench voltage curve representing the voltage at which the plasma turns off. It is shown that, for a point to point microgap (e.g. the microgap between two needle probes) which describes many realistic microdevices, neither Paschen's law applies nor field emission is noticeable. Although normally $V_{\\mathrm{BD}}>V_{\\mathrm{Q}}$, it is observed that depending on environmental parameters of argon, such as pressure and the driving circuitry, plasma can exist in a different state with equal $V_{\\mathrm{BD}}$ and $V_{\\mathrm{Q}}$. Using emission line spectroscopy, it is shown that $V_{\\mathrm{BD}}$ and $V_{\\mathrm{Q}}$ are equal if the atomic excitation by the electric field dipole moment dominantly leads to one of the argon's metastable states ($4P_{5...

  19. PF-04886847 (an inhibitor of plasma kallikrein) attenuates inflammatory mediators and activation of blood coagulation in rat model of lipopolysaccharide (LPS)-induced sepsis.

    PubMed

    Kolte, D; Bryant, J W; Gibson, G W; Wang, J; Shariat-Madar, Z

    2012-06-01

    The plasma kallikrein-mediated proteolysis regulates both thrombosis and inflammation. Previous study has shown that PF-04886847 is a potent and competitive inhibitor of kallikrein, suggesting that it might be useful for the treatment of kallikrein-kinin mediated inflammatory and thrombotic disorders. In the rat model of lipopolysaccharide (LPS) -induced sepsis used in this study, pretreatment of rats with PF-04886847 (1 mg/kg) prior to LPS (10 mg/kg) prevented endotoxin-induced increase in granulocyte count in the systemic circulation. PF-04886847 significantly reduced the elevated plasma 6-keto PGF1? levels in LPS treated rats, suggesting that PF-04886847 could be useful in preventing hypotensive shock during sepsis. PF-04886847 did not inhibit LPS-induced increase in plasma TNF-? level. Pretreatment of rats with PF-04886847 prior to LPS did not attenuate endotoxin-induced decrease in platelet count and plasma fibrinogen levels as well as increase in plasma D-dimer levels. PF-04886847 did not protect the animals against LPS-mediated acute hepatic and renal injury and disseminated intravascular coagulation (DIC). Since prekallikrein (the zymogen form of plasma kallikrein) deficient patients have prolonged activated partial thromboplastin time (aPTT) without having any bleeding disorder, the anti-thrombotic property and mechanism of action of PF-04886847 was assessed. In a rabbit balloon injury model designed to mimic clinical conditions of acute thrombotic events, PF-04886847 reduced thrombus mass dose-dependently. PF-04886847 (1 mg/kg) prolonged both aPTT and prothrombin time (PT) in a dose-dependent manner. Although the findings of this study indicate that PF-04886847 possesses limited anti-thrombotic and anti-inflammatory effects, PF-04886847 may have therapeutic potential in other kallikrein-kinin mediated diseases. PMID:22352684

  20. A collisional and radiative model of argon plasma for application to ionization phenomena behind a shock wave

    Microsoft Academic Search

    Y. Takano; T. Akamatsu

    1982-01-01

    A formulation has been performed for the description of excited-level population-densities and gasdynamic properties in nonequilibrium ionizing argon gas. The energy-level structure of an argon atom is assumed to be composed of six actual levels and higher hydrogenic levels. The ionization and excitation due to atom-atom and atom-electron inelastic collisions, as well as radiative transition including the self-absorption effect, are

  1. Laser Optogalvanic Spectroscopy pf Neon and Argon in a Discharge Plasma and its Significance for Microgravity Combustion

    NASA Technical Reports Server (NTRS)

    Misra, Prabhakar; Haridass, C.; Major, H.

    1999-01-01

    A detailed study of combustion mechanisms in flames, employing laser-based diagnostics, has provided good knowledge and understanding of the physical phenomena, and led to better characterization of the dynamical and chemical combustion processes, both under low-gravity (in space) and normal gravity (in ground based facilities, e.g. drop towers). Laser induced fluorescence (LIF), laser-induced incandescence (LII) and LIF thermometry have been widely used to perform nonintrusive measurements and to better understand combustion phenomena. Laser optogalvanic (LOG) spectroscopy has well-established applications in ion mobility measurements, atomic and molecular spectroscopy, ionization rates, recombination rates, velocity measurements and as a combustion probe for trace element detection. Absorption spectra of atomic and molecular species in flames can be obtained via LOG spectroscopy by measuring the voltage and current changes induced by laser irradiation. There are different kinds of processes that contribute to a discharge current, namely: (1) electron impact ionization, (2) collisions among the excited atoms of the discharge species and (3) Penning ionization. In general, at higher discharge currents, the mechanism of electron impact ionization dominates over Penning ionization, whereby the latter is hardly noticeable. In a plasma, whenever the wavelength of a laser coincides with the absorption of an atomic or molecular species, the rate of ionization of the species momentarily increases or decreases due to laser-assisted acceleration of collisional ionization. Such a rate of change in the ionization is monitored as a variation in the transient current by inserting a high voltage electrode into the plasma. Optogalvanic spectroscopy in discharges has been useful for characterizing laser line-widths and for providing convenient calibration lines for tunable dye lasers in the ultraviolet, visible and infrared wavelength regions. Different kinds of quantitative information, such as the electron collisional ionization rate, can be extracted from the complex processes occurring within the discharge. In the optogalvanic effect (OGE), there is no problem of overlap from background emissions, and hence even weak signals can be detected with a high signal-to-noise ratio, which makes the optogalvanic effect sensitive enough to resolve vibrational changes in molecular bonds and differences in energy levels brought about by different electron spins. For calibration purposes, neon and argon gaseous discharges have been employed most extensively, because these gases are commonly used as buffer gases within hollow-cathode lamps and provide an acceptable density of calibration lines. In the present work, our main aim has been to understand the dominant physical processes responsible for the production of the OGE signal, based on the extensive time resolved optogalvanic waveforms recorded, and also to extract quantitative information on the rates of excited state collisional processes.

  2. Hydroxyurea Increases Plasma Concentrations of Microparticles and Reduces Coagulation Activation and Fibrinolysis in Patients with Sickle Cell Anemia.

    PubMed

    Brunetta, Denise Menezes; De Santis, Gil Cunha; Silva-Pinto, Ana Cristina; Oliveira de Oliveira, Luciana Correa; Covas, Dimas Tadeu

    2014-12-01

    Microparticles (MPs) are present in healthy subjects and their concentration increases in patients at high risk of thrombosis. We evaluated 10 patients with sickle cell anemia (SCA) treated with hydroxyurea (HU) and 13 SCA patients without this treatment. MP concentrations were determined by flow cytometry. Coagulation was evaluated using the thrombin-antithrombin complex (TAT) and D-dimers. Total MP concentrations were increased in the HU-treated group (265 × 10(6)/ml vs. 67.45 × 10(6)/ml; p = 0.0026), as well as MPs derived from RBC (67.83 × 10(6)/ml vs. 26.31 × 10(6)/ml; p = 0.05), monocytes (51.31 × 10(6)/ml vs. 9.03 × 10(6)/ml; p = 0.0084), monocytes with tissue factor (TF) expression (2.27 × 10(6)/ml vs. 0.27 × 10(6)/ml; p = 0.0058), endothelium (49.42 × 10(6)/ml vs. 7.23 × 10(6)/ml; p = 0.007) and endothelium with TF (1.42 × 10(6)/ml vs. 0.26 × 10(6)/ml; p = 0.0043). Furthermore, the concentrations of TAT (7.56 vs. 10.98 µg/l; p = 0.014) and D-dimers (0.65 vs. 1.29 µg/ml; p = 0.007) were reduced with HU. The MP elevation may suggest a direct cytotoxic effect of HU. Another explanation is a cell surface increase secondary to a megaloblastic process, resulting in increased vesicle release. In our opinion, the known benefits of HU on SCA patients, along with the reduction in coagulation activation, surpass its potential detrimental effect on MPs. Future studies should elucidate the role of MPs and demonstrate their significance in different contexts. © 2014 S. Karger AG, Basel. PMID:25472687

  3. Argon Plasma Surgery for Treatment of Inferior Turbinate Hypertrophy: A Long-Term Follow-Up in 157 Patients

    Microsoft Academic Search

    E. Ferri; E. Armato; S. Cavaleri; P. Capuzzo; F. Ianniello

    2003-01-01

    Chronic nasal obstruction is a common disorder, mostly caused by hypertrophic inferior turbinates. In cases of nonresponse to conservative medical management, the surgical reduction of the inferior turbinates is often required. Surgical techniques for the reduction of hyperplastic nasal turbinates include monopolar or bipolar coagulation, partial or total reduction of the turbinates with a conchotome or scissors and laser surgery

  4. First principles transport coefficients and reaction rates of Ar_2^+ ions in argon for cold plasma jet modeling

    NASA Astrophysics Data System (ADS)

    Chicheportiche, Alexandre; StachoÅ, Martin; Benhenni, Malika; Gadéa, Florent Xavier; Kalus, René; Yousfi, Mohammed

    2014-10-01

    Momentum-transfer collision cross-sections and integral collision cross-sections for the collision-induced dissociation are calculated for collisions of ionized argon dimers with argon atoms using a nonadiabatic semiclassical method with the electronic Hamiltonian calculated on the fly via a diatomics-in-molecules semiempirical model as well as inverse-method modeling based on simple isotropic rigid-core potential. The collision cross-sections are then used in an optimized Monte Carlo code for evaluations of the Ar_2^+ mobility in argon gas, longitudinal diffusion coefficient, and collision-induced dissociation rates. A thorough comparison of various theoretical calculations as well as with available experimental data on the Ar_2^+ mobility and collision cross-sections is performed. Good agreement is found between both theoretical approaches and the experiment. Analysis of the role of inelastic processes in Ar_2^+/Ar collisions is also provided.

  5. Usefulness of standard plasma coagulation tests in the management of perioperative coagulopathic bleeding: is there any evidence?

    PubMed

    Haas, T; Fries, D; Tanaka, K A; Asmis, L; Curry, N S; Schöchl, H

    2015-02-01

    Standard laboratory coagulation tests (SLTs) such as prothrombin time/international normalized ratio or partial thromboplastin time are frequently used to assess coagulopathy and to guide haemostatic interventions. However, this has been challenged by numerous reports, including the current European guidelines for perioperative bleeding management, which question the utility and reliability of SLTs in this setting. Furthermore, the arbitrary definition of coagulopathy (i.e. SLTs are prolonged by more than 1.5-fold) has been questioned. The present study aims to review the evidence for the usefulness of SLTs to assess coagulopathy and to guide bleeding management in the perioperative and massive bleeding setting. Medline was searched for investigations using results of SLTs as a means to determine coagulopathy or to guide bleeding management, and the outcomes (i.e. blood loss, transfusion requirements, mortality) were reported. A total of 11 guidelines for management of massive bleeding or perioperative bleeding and 64 studies investigating the usefulness of SLTs in this setting were identified and were included for final data synthesis. Referenced evidence for the usefulness of SLTs was found in only three prospective trials, investigating a total of 108 patients (whereby microvascular bleeding was a rare finding). Furthermore, no data from randomized controlled trials support the use of SLTs. In contrast, numerous investigations have challenged the reliability of SLTs to assess coagulopathy or guide bleeding management. There is actually no sound evidence from well-designed studies that confirm the usefulness of SLTs for diagnosis of coagulopathy or to guide haemostatic therapy. PMID:25204698

  6. Ultraviolet versus infrared: Effects of ablation laser wavelength on the expansion of laser-induced plasma into one-atmosphere argon gas

    SciTech Connect

    Ma Qianli; Motto-Ros, Vincent; Laye, Fabrice; Yu Jin [Universite de Lyon, F-69622, Lyon, France, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France); Lei Wenqi; Bai Xueshi; Zheng Lijuan; Zeng Heping [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai (China)

    2012-03-01

    Laser-induced plasma from an aluminum target in one-atmosphere argon background has been investigated with ablation using nanosecond ultraviolet (UV: 355 nm) or infrared (IR: 1064 nm) laser pulses. Time- and space-resolved emission spectroscopy was used as a diagnostics tool to have access to the plasma parameters during its propagation into the background, such as optical emission intensity, electron density, and temperature. The specific feature of nanosecond laser ablation is that the pulse duration is significantly longer than the initiation time of the plasma. Laser-supported absorption wave due to post-ablation absorption of the laser radiation by the vapor plume and the shocked background gas plays a dominant role in the propagation and subsequently the behavior of the plasma. We demonstrate that the difference in absorption rate between UV and IR radiations leads to different propagation behaviors of the plasma produced with these radiations. The consequence is that higher electron density and temperature are observed for UV ablation. While for IR ablation, the plasma is found with lower electron density and temperature in a larger and more homogenous axial profile. The difference is also that for UV ablation, the background gas is principally evacuated by the expansion of the vapor plume as predicted by the standard piston model. While for IR ablation, the background gas is effectively mixed to the ejected vapor at least hundreds of nanoseconds after the initiation of the plasma. Our observations suggest a description by laser-supported combustion wave for the propagation of the plasma produced by UV laser, while that by laser-supported detonation wave for the propagation of the plasma produced by IR laser. Finally, practical consequences of specific expansion behavior for UV or IR ablation are discussed in terms of analytical performance promised by corresponding plasmas for application with laser-induced breakdown spectroscopy.

  7. Convoluted effect of laser fluence and pulse duration on the property of a nanosecond laser-induced plasma into an argon ambient gas at the atmospheric pressure

    SciTech Connect

    Bai Xueshi; Ma Qianli; Motto-Ros, Vincent; Yu Jin [Universite de Lyon, F-69622, Lyon, France, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France); Sabourdy, David; Nguyen, Luc; Jalocha, Alain [CILAS Laser Company, Photonics Department, 45000 Orleans (France)

    2013-01-07

    We studied the behavior of the plasma induced by a nanosecond infrared (1064 nm) laser pulse on a metallic target (Al) during its propagation into argon ambient gas at the atmospheric pressure and especially over the delay interval ranging from several hundred nanoseconds to several microseconds. In such interval, the plasma is particularly interesting as a spectroscopic emission source for laser-induced plasma spectroscopy (LIBS). We show a convoluted effect between laser fluence and pulse duration on the structure and the emission property of the plasma. With a relatively high fluence of about 160 J/cm{sup 2} where a strong plasma shielding effect is observed, a short pulse of about 4 ns duration is shown to be significantly more efficient to excite the optical emission from the ablation vapor than a long pulse of about 25 ns duration. While with a lower fluence of about 65 J/cm{sup 2}, a significantly more efficient excitation is observed with the long pulse. We interpret our observations by considering the post-ablation interaction between the generated plume and the tailing part of the laser pulse. We demonstrate that the ionization of the layer of ambient gas surrounding the ablation vapor plays an important role in plasma shielding. Such ionization is the consequence of laser-supported absorption wave and directly dependent on the laser fluence and the pulse duration. Further observations of the structure of the generated plume in its early stage of expansion support our explanations.

  8. An investigation of Ar metastable state density in low pressure dual-frequency capacitively coupled argon and argon-diluted plasmas

    NASA Astrophysics Data System (ADS)

    Liu, Wen-Yao; Xu, Yong; Liu, Yong-Xin; Peng, Fei; Guo, Qian; Li, Xiao-Song; Zhu, Ai-Min; Wang, You-Nian

    2015-01-01

    An tunable diode laser absorption spectroscopy has been used to determine the Ar*(3P2) and Ar*(3P0) metastable atoms densities in dual-frequency capacitively coupled plasmas. The effects of different control parameters, such as high-frequency power, gas pressure and content of Ar, on the densities of two metastable atoms and electron density were discussed in single-frequency and dual-frequency Ar discharges, respectively. Particularly, the effects of the pressure on the axial profile of the electron and Ar metastable state densities were also discussed. Furthermore, a simple rate model was employed and its results were compared with experiments to analyze the main production and loss processes of Ar metastable states. It is found that Ar metastable state is mainly produced by electron impact excitation from the ground state, and decayed by diffusion and collision quenching with electrons and neutral molecules. Besides, the addition of CF4 was found to significantly increase the metastable destruction rate by the CF4 quenching, especially for large CF4 content and high pressure, it becomes the dominant depopulation process.

  9. Safety and efficacy of plasma-derived coagulation factor IX concentrate (AlphaNine® SD) in patients with haemophilia B undergoing surgical intervention: a single institution retrospective analysis.

    PubMed

    Quon, D V K; Logan, L

    2011-01-01

    While coagulation factor replacement is essential in surgical intervention in haemophilia B patients, few studies are available on the safety and efficacy of plasma-derived factor IX (FIX) for haemostasis during surgery. This retrospective study examined outcomes in these patients. A total of 20 patients who underwent 29 surgical procedures at the Hemophilia Treatment Center at Orthopaedic Hospital in Los Angeles, California, were identified and their inpatient charts were reviewed and abstracted. Outcomes included pre- and postoperative FIX dosing, recovery of FIX, blood loss, use of blood products, safety and haemostatic response. Identified patients had mild (10%), moderate (15%) or severe (75%) haemophilia B, and average age at surgery was 48.5 years. All surgical procedures were major (orthopaedic 89.7%; abdominal 10.3%), all were completed under general anaesthesia, and average time in surgery was 3.25 h. Average hospital length of stay was 11.0 days [standard deviation (SD) = 8.5] and all patients were discharged home. All patients were treated with AlphaNine® SD at an average dose of 254.9 IU kg(-1) (SD = 65.4) on the day of surgery and the dose was adjusted over the course of hospital stay. Mean perioperative blood loss was 255.5 mL (SD = 283.1) and blood replacement was required in only two surgeries (6.9%). FIX recovery analysis performed preoperatively related well to FIX levels obtained. Identified patients had little blood loss perioperatively and had no bleeding related complications. Plasma-derived FIX pre- and postoperatively appeared to be a safe and effective treatment in haemophilia B patients undergoing surgery. PMID:20618876

  10. Emission spectra of an argon inductively coupled plasma in the vacuum ultraviolet: background spectra from 85 to 200 nm

    NASA Astrophysics Data System (ADS)

    Carr, J. W.; Blades, M. W.

    The background spectra emitted from an argon ICP discharge have been recorded over the spectral range 85 to 200 nm. These vacuum ultraviolet spectra were acquired by coupling the ICP to a 0.5-m Seya-Namioka vacuum monochromator, through a helium purged side-arm. Background features observed include emission from the resonance lines of ArI, and emission from gas impurities such as oxygen, nitrogen, carbon and hydrogen.

  11. Interspecies differences in coagulation profile.

    PubMed

    Siller-Matula, Jolanta M; Plasenzotti, Roberto; Spiel, Alexander; Quehenberger, Peter; Jilma, Bernd

    2008-09-01

    Many animals are used in research on blood coagulation and fibrinolysis, but the relevance of animal models to human health is often questioned because of differences between species. The objective was to find an appropriate animal species, which mimics the coagulation profile in humans most adequately. Species differences in the coagulation profile with and without thrombin stimulation in vitro were assessed in whole blood by Rotation Thromboelastometry (ROTEM). Endogenous thrombin generation was measured in platelet-poor plasma. Measurements were performed in blood from five different species: humans, rats, pigs, sheep and rabbits. In humans and sheep, the clotting time (ROTEM) was in the same range with or without thrombin stimulation and a 100-fold lower dose of thrombin (0.002 IU) was required to cause a shortening in the clotting time as compared to rats, pigs and rabbits (0.2 IU) (p<0.05). Similarly, the endogenous thrombin potential (ETP) was in the same range in humans and sheep. The maximum clot firmness with or without thrombin stimulation was similar in rabbits and humans. The maximum lysis with or without thrombin stimulation was similar in humans and pigs. Significant species differences exist in the coagulation profile with or without thrombin stimulation. Most importantly, sheep had a clotting time most similar to humans and could thus be a suitable species for translational coagulation studies. Moreover, our findings confirm the potential usefulness of pigs as an experimental species to study fibrinolytic pathway and support the usefulness of rabbits as a species for examining platelets. PMID:18766254

  12. Application of abnormally high sputtering rate of PbTe(Te) single crystals during inductively coupled argon plasma treatment for fabrication of nanostructures

    NASA Astrophysics Data System (ADS)

    Zimin, S. P.; Gorlachev, E. S.; Amirov, I. I.; Naumov, V. V.; Bagiyeva, G. Z.

    2015-03-01

    This paper reports the investigations of the sputtering process of (111) oriented single crystals of PbTe with excess tellurium (4 at.%) in RF high-density low-pressure inductively coupled argon plasma. An increase of 1.6 times the sputtering rate of lead telluride in comparison with the classical case of single-crystal state with a slight deviation from stoichiometry is shown and the explanation of the results is carried out based on the analysis of the crystal point defects. The active sputtering is used in a new approach to form lead telluride nanostructures on oxidized Si substrates via the vapour–liquid–solid (VLS) redeposition mechanism, and the fabrication of PbTe nanocones, nanocubes and nanowires with various geometrical parameters is demonstrated.

  13. Measurement of ion density in an atmospheric pressure argon with pin-to-plate dielectric barrier discharge by resonance of plasma radiation

    NASA Astrophysics Data System (ADS)

    Qi, Bing; Pan, Lizhu; Zhou, Qiujiao; Huang, Jianjun; Liu, Ying

    2014-12-01

    The measurements of the ion densities in the atmospheric AC barrier corona argon discharge are carried out by receiving and analyzing the frequencies of the electromagnetic radiation emitted from the plasma. An auxiliary excitation source composed of a pin-to-pin discharge system is introduced to excite the oscillations of the main discharge. To analyze the resonance mechanism, a complemented model based on a one-dimensional description of forced vibrations is given. Calculations indicate that Ar2 + is the dominant ion ( ˜ 89 % in number density). By analyzing resonance frequencies, the ion densities of Ar2 + are in the order of 10 19 ˜ 10 20 m - 3 and increase slowly as the applied voltage increases.

  14. Transfusion in trauma: thromboelastometry-guided coagulation factor concentrate-based therapy versus standard fresh frozen plasma-based therapy

    PubMed Central

    2011-01-01

    Introduction Thromboelastometry (TEM)-guided haemostatic therapy with fibrinogen concentrate and prothrombin complex concentrate (PCC) in trauma patients may reduce the need for transfusion of red blood cells (RBC) or platelet concentrate, compared with fresh frozen plasma (FFP)-based haemostatic therapy. Methods This retrospective analysis compared patients from the Salzburg Trauma Centre (Salzburg, Austria) treated with fibrinogen concentrate and/or PCC, but no FFP (fibrinogen-PCC group, n = 80), and patients from the TraumaRegister DGU receiving ? 2 units of FFP, but no fibrinogen concentrate/PCC (FFP group, n = 601). Inclusion criteria were: age 18-70 years, base deficit at admission ?2 mmol/L, injury severity score (ISS) ?16, abbreviated injury scale for thorax and/or abdomen and/or extremity ?3, and for head/neck < 5. Results For haemostatic therapy in the emergency room and during surgery, the FFP group (ISS 35.5 ± 10.5) received a median of 6 units of FFP (range: 2, 51), while the fibrinogen-PCC group (ISS 35.2 ± 12.5) received medians of 6 g of fibrinogen concentrate (range: 0, 15) and 1200 U of PCC (range: 0, 6600). RBC transfusion was avoided in 29% of patients in the fibrinogen-PCC group compared with only 3% in the FFP group (P< 0.001). Transfusion of platelet concentrate was avoided in 91% of patients in the fibrinogen-PCC group, compared with 56% in the FFP group (P< 0.001). Mortality was comparable between groups: 7.5% in the fibrinogen-PCC group and 10.0% in the FFP group (P = 0.69). Conclusions TEM-guided haemostatic therapy with fibrinogen concentrate and PCC reduced the exposure of trauma patients to allogeneic blood products. PMID:21375741

  15. Departure from Local Thermodynamic Equilibrium in argon plasmas sustained in a Torche à Injection Axiale sur Guide d'Ondes

    NASA Astrophysics Data System (ADS)

    Rincón, R.; Muñoz, J.; Calzada, M. D.

    2015-01-01

    Plasma torches are suitable plasma sources for a wide range of applications. The capability of these discharges to produce processes like sample excitation or decomposition of molecules inside them depends on the density of the plasma species and their energies (temperatures). The relation between these parameters determines the specific state of thermodynamic equilibrium in the discharge. Thus, the understanding of plasma possibilities for application purposes is related to the knowledge of the plasma thermodynamic equilibrium degree. In this paper a discussion about the equilibrium state for Ar plasmas generated by using a Torche à Injection Axiale sur Guide d'Ondes, TIAGO device, is presented. Emission spectroscopy techniques were used to measure gas temperature and electron density at the exit of the nozzle torch and along the dart. Boltzmann-plots as well as bp parameters were calculated to characterize the type and degree of departure from partial Local Saha Equilibrium (pLSE). This study indicates that the closer situation to Local Thermodynamic Equilibrium (LTE) of the plasma corresponds to larger Ar flows which highlights the importance of the nitrogen (atmosphere surrounding the plasma) in the kinetics of Ar-TIAGO discharges.

  16. Bipolar coagulation - capable microforceps

    Microsoft Academic Search

    TOSHIKAZU KAWAI; KAZUTOSHI KAN; KAZUHIRO HONGO; KOUJI NISHIZAWA; FUJIO TAJIMA; MASAKATSU G. FUJIE; TAKEYOSHI DOHI; KINTOMO TAKAKURA

    2005-01-01

    Microforceps that can be used with the hyper utility mechatronic assistant system (HUMAN) for bipolar coagulation in minimally invasive neurosurgery were developed. A method of using two sets of those forceps for bipolar coagulation was developed, in which electrical current is passed through the drive wires to the forceps tips to form an electrical circuit. A prototype mechanism that employs

  17. The determination of ranges of selected properties of an argon plasma using an electric arc of limited power

    E-print Network

    Farquhar, Bannister Wells

    1963-01-01

    Energy Inputs Range of Plasmas Generated 0 12 15 27 28 Close-up of Arc Chamber and Plasma Jet. . . , 41 Over-all View of Plasma Generator 41 10 The Arc Chamber, Control Console and Instrumentation 42 Exploded View of Nozzle Flange, Nozzle... the manometer to fluctuate rapidly, prohibiting accurate readings. The pressure in the vacuum tank and the pressure of the pitot tube were measured on Meriam, type W, Madel A-203, 30-inch mercury manometers mounted on the control console. The pitot tube...

  18. Observation of inactivation of Bacillus sbtilis spores under exposures of oxygen added argon atmospheric pressure plasma jet

    NASA Astrophysics Data System (ADS)

    Shen, Jie; Cheng, Cheng; Zhao, Ying; Xiao, Dezhi; Lan, Yan; Xie, Hongbing; Cheng, Junli; Meng, Yuedong; Li, Jiangang; Chu, Paul K.

    2014-11-01

    The inactivation of Bacillus subtilis spores by an Ar plasma jet mixed with different amounts of oxygen is reported. 5.8 × 106 B. subtilis spores are sterilized by an Ar/O2 (8.7%) plasma jet after exposure for 2 min. The densities of ozone and oxygen radicals in the Ar/O2 plasma jet increase with oxygen concentration and are estimated by optical spectroscopy diagnostic. The malondialdehyde (MDA) test shows that oxygen radicals participate in bacterial inactivation. Scanning electron microscopy (SEM) reveals the deformation of the spore shape due to etching by oxygen radicals and the dependence of the degree of deformation on the density of oxygen radicals.

  19. Comparative 2D Radiation MHD Simulations of Argon Gas Puff Z-pinch Plasma Experiments on the Sandia Z Machine Using the Radiative Diffusion and CRE Transport Models

    NASA Astrophysics Data System (ADS)

    Chong, Y. K.; Thornhill Giuliani, J. W., Jr.; Apruzese, J. P.; Terry, R. E.; Davis, J.

    2001-10-01

    The recent development of the computationally efficient tabulated collisional radiative equilibrium (TCRE) radiation transport model(J.W. Thornhill, J.P. Apruzese, J. Davis, R.W. Clark, A.L. Velikovich, J.L. Giuliani, Jr., Y.K. Chong, K.G. Whitney, C. Deeney, C.A. Coverdale and F.L. Cochran, Phys. Plasmas 7, 3480 (2001).) has made possible full multidimensional radiation MHD simulations of hot dense Z-pinch plasmas with a realistic description of the non-LTE ionization dynamics and radiation transport physics. In this study, we focus on the implementation of the TCRE radiation transport model in the Mach2 2D radiation MHD code. An application of the model is made through a full dynamical simulation of an argon gas puff pinch driven by a circuit model of the Z generator. An analysis of the simulation, in particular, the K- and L-shell radiation yields, as well as the spectral and spatial characteristics of the radiation will be presented. In addition, a comparison of this multidimensional transport method will be made with the existing radiative diffusion model.

  20. Initiation and propagation of coagulation from tissue factor-bearing cell monolayers to plasma: initiator cells do not regulate spatial growth rate

    Microsoft Academic Search

    M. V. OVANESOV; N. M. ANANYEVA; M. A. PANTELEEV; F. I. ATAULLAKHANOV; E. L. SAENKO

    2005-01-01

    Summary. Exposure of tissue factor (TF)-bearing cells to blood is the initial event in coagulation and intravascular thrombus formation. However, the mechanisms which deter- mine thrombus growth remain poorly understood. To explore whether the procoagulant activity of vessel wall-bound cells regulates thrombus expansion, we studied in vitro spatial clot growth initiated by cultured human cells of different types in contact

  1. 2D collisional-radiative model for non-uniform argon plasmas: with or without ‘escape factor’

    NASA Astrophysics Data System (ADS)

    Zhu, Xi-Ming; Vaskov Tsankov, Tsanko; Luggenhölscher, Dirk; Czarnetzki, Uwe

    2015-03-01

    Collisional-radiative models for excited rare-gas atoms in low-temperature plasmas are a widely investigated topic. When these plasmas are optically thick, an ‘escape factor’ is introduced into the models to account for the reabsorption of photons (so-called radiation trapping process). This factor is usually obtained assuming a uniform density profile of the excited species; however, such an assumption is often not satisfied in a bounded plasma. This article reports for the first time a self-consistent collisional-radiative model without using an ad hoc ‘escape factor’ for excited Ar atoms in the 2p states (in Paschen’s notation). Rather, the rate balance equations—i.e. the radiation transfer equations—of the 2p states are numerically solved to yield the actual density profiles. The predictions of this self-consistent model and a model based on the escape factor concept are compared with spatially-resolved emission measurements in a low-pressure inductive Ar plasma. The self-consistent model agrees well with the experiment but the ‘escape factor’ model shows considerable deviations. By the comparative analysis the limitations and shortcomings of the escape factor concept as adopted in a significant number of works are revealed.

  2. Determination of ionic and neutral components of argon-methyl methacrylate radiofrequency discharge plasma by mass spectrometry

    SciTech Connect

    Shcheglov, A.N.; Vasilets, V.N.; Ponomarev, A.N. [Institute of Energy Problems of Chemical Physics, Moscow (Russian Federation)

    1995-09-01

    Positive ions and neutral species formed in the plasma of a radiofrequency discharge in an argonmethyl methacrylate (MMA) mixture at 5.28 MHz, discharge power 12 - 130 W, pressure 10 - 100 Pa, and 0.5 - 10% MMA content of the gas mixture were investigated by mass spectrometry. Over 30 different ionic species were identified in the plasma under various experimental conditions. The most abundant plasma ions were as follows (the m/e values are given in parentheses): CH{sub 3}{sup +} (15), C{sub 2}H{sub 2}{sup +} (26), C{sub 2}H{sub 3}{sup +} (27), C{sub 2}H{sub 4}{sup +}, CO{sup +} (28), C{sub 2}H{sub 5}{sup +}, C{sub 2}H{sub 5}{sup +}, HCO{sup +} (29), C{sub 3}H{sub 3}{sup +} (39), Ar{sup +} (40), C{sub 3}H{sub 5}{sup +} (41), COOCH{sub 3}{sup +} (101). At the MMA concentrations studied, Ar{sup +} was the principal ionic component of the plasma. Among the neutral plasma components, 28 compounds were identified, including C{sub 1}-C{sub 6} hydrocarbons, H{sub 2},H{sub 2}O, CO, HCOH, CH{sub 3}OH, CO{sub 2}, CH{sub 3}COCH{sub 3}, and C{sub 3}H{sub 7}COH. The experimental data suggest that both electron-impact-induced dissociation and ion-molecule reactions involving Ar{sup +}MMA mixture.

  3. Bustling argon: biological effect

    PubMed Central

    2013-01-01

    Argon is a noble gas in group 18 of the periodic table. Certificated to exist in air atmosphere merely one century ago, discovery of argon shows interesting stories of researching and exploring. It was assumed to have no chemical activity. However, argon indeed present its biological effect on mammals. Narcotic effect of argon in diving operation and neur-protective function of argon in cerebral injury demonstrate that argon has crucial effect and be concentrated on is necessary. Furthermore, consider to be harmless to human, argon clinical application in therapy would be another option. PMID:24088583

  4. Coagulation and Mental Disorders

    PubMed Central

    Hoirisch-Clapauch, Silvia; Nardi, Antonio Egidio; Gris, Jean-Christophe; Brenner, Benjamin

    2014-01-01

    The neurovascular unit is a key player in brain development, homeostasis, and pathology. Mental stress affects coagulation, while severe mental illnesses, such as recurrent depression and schizophrenia, are associated with an increased thrombotic risk and cardiovascular morbidity. Evidence indicates that the hemostatic system is involved to some extent in the pathogenesis, morbidity, and prognosis of a wide variety of psychiatric disorders. The current review focuses on emerging data linking coagulation and some psychiatric disorders. PMID:25386352

  5. Density of atoms in Ar*(3p{sup 5}4s) states and gas temperatures in an argon surfatron plasma measured by tunable laser spectroscopy

    SciTech Connect

    Huebner, S.; Carbone, E. A. D.; Mullen, J. J. A. M. van der [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven (Netherlands); Sadeghi, N. [LIPhy, Universite Joseph Fourier and CNRS, UMR 5588, Grenoble F-38041 (France)

    2013-04-14

    This study presents the absolute argon 1 s (in Paschens's notation) densities and the gas temperature, T{sub g}, obtained in a surfatron plasma in the pressure range 0.6510 mbar, for which the pressure broadening can no more be neglected. T{sub g} is in the range of 480-750 K, increasing with pressure and decreasing with the distance from the microwave launcher. Taking into account the line of sight effects of the absorption measurements, a good agreement is found with our previous measurements by Rayleigh scattering of T{sub g} at the tube center. In the studied pressure range, the Ar(4 s) atom densities are in the order of 10{sup 16}-10{sup 18} m{sup -3}, increasing towards the end of the plasma column, decreasing with the pressure. In the low pressure side, a broad minimum is found around 10

  6. Nonlinear Interaction Between the Radiation and Multidimensional Plasma in Large Diameter Structured Argon Gas Puff Z-Pinch Loads

    NASA Astrophysics Data System (ADS)

    Chong, Y. K.; Thornhill, J. W.; Velikovich, A. L.; Apruzese, J. P.; Davis, J.; Qi, N.; Sze, H.; Levine, J. S.; Failor, B. H.

    2006-10-01

    It has recently been demonstrated that one can efficiently produce K-shell x-ray radiation with z pinches imploded from larger initial diameters, by longer current pulses than previously thought possible, using a ``pusher-stabilizer-radiator'' load formed by a supersonic nozzle injecting outer and inner annular shells and a high-density central jet between the cathode and the anode [1]. We present a detailed numerical investigation of the implosions of such loads. Our simulations were performed with the 2D RMHD Mach2 code incorporating the dynamical domain tabular collisional radiative equilibrium (DDTCRE) radiation transport model [2]. This model provides a realistic description of the self-consistent multidimensional non-local non-LTE ionization dynamics and radiation transport physics in a computationally efficient manner. A numerical simulation analysis of various nozzle load configurations, with/without the central jet and/or shells, is used to further assess and validate the physical model by simulating the experimental spectra, plasma images and radiation emission characteristics. [1] H. Sze et al., PRL 95, 105001(2005). [2] Y. K. Chong et al., ICOPS 2005, Monterey, CA.

  7. The role of platelets in blood coagulation during thrombus formation in flow

    E-print Network

    Paris-Sud XI, Université de

    The role of platelets in blood coagulation during thrombus formation in flow A. Tosenberger1,2 , F of aggregating platelets with biochemical reactions in plasma that participate in blood coagulation (DPD) is used to model plasma flow with platelets while fibrin concentration is described

  8. The Coagulated Behavior of Latex Particles in a Seed Coagulation

    NASA Astrophysics Data System (ADS)

    Fukui, Masatsugu; Ueda, Takashi; Komoda, Yoshiyuki; Suzuki, Hiroshi; Usui, Hiromoto

    2008-07-01

    The coagulated behavior of latex particles in a seed coagulation was investigated. The latex particle formed the higher order coagulated structure, which consists of primary coagulates, and it was found that the temperature and the mixing condition significantly affected the size of cluster. We also proposed the procedure to predict the size of cluster from viscosity data of latex particle slurry by the use of the thixotropy model presented by Usui

  9. Characterization of the behavior of chemically reactive species in a nonequilibrium inductively coupled argon-hydrogen thermal plasma under pulse-modulated operation

    SciTech Connect

    Ye, Rubin; Ishigaki, Takamasa; Taguchi, Hiroyuki; Ito, Shigeru; Murphy, Anthony B.; Lange, Hubert [Nano Ceramics Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Department of Pure and Applied Chemistry, Tokyo University of Science, Yamazaki, Noda, Chiba 278-8510 (Japan); CSIRO Industrial Physics, P.O. Box 218, Lindfield, New South Wales 2070 (Australia); Department of Chemistry, Warsaw University, Pasteur Street 1, 02-093 Warsaw (Poland)

    2006-11-15

    The temporal and spatial dependence of species densities in a pulse-modulated inductively coupled plasma (PM-ICP) in an argon-hydrogen mixture was investigated by means of numerical modeling, taking into account time dependence, two temperatures, and chemical nonequilibrium, and also through spectroscopic measurements. Conservation equations for mass, momentum, electron energy, heavy-species energy, each species, and the electromagnetic field were developed and solved self-consistently. The transient behavior of the mass fraction of each species was determined by including chemical kinetics source terms in the species conservation equations. Fourteen chemical reactions involving seven species (e, Ar, Ar{sup +}, H{sub 2}, H{sub 2}{sup +}, H, and H{sup +}) were considered. The transport properties were evaluated based on the local species densities using the first-order approximation of the Chapman-Enskog method. Time-resolved electron density profiles were obtained from measurements of the Stark broadening of the H{sub {beta}} line (486.1 nm), performed using an optical system positioned using a stepper motor. The investigations were conducted for a maximum power level of 11.7 kW with a duty factor of 66.7% and at a pressure of 27 kPa. Reasonable agreement was found between the predicted and measured electron densities. The electron density in the discharge region varied considerably over a pulse cycle, while the hydrogen atom density remained high throughout the cycle, and peaked in a region that has been experimentally demonstrated to have optimal efficiency for hydrogen doping of materials. The main mechanisms responsible for the production of the relevant species in the PM-ICP are discussed.

  10. Titanium Dioxide Coatings Sprayed by a Water-Stabilized Plasma Gun (WSP) with Argon and Nitrogen as the Powder Feeding Gas: Differences in Structural, Mechanical and Photocatalytic Behavior

    NASA Astrophysics Data System (ADS)

    Ctibor, P.; Pala, Z.; Sedlá?ek, J.; Štengl, V.; Píš, I.; Zahoranová, T.; Nehasil, V.

    2012-06-01

    Titanium dioxide coatings were sprayed by a water-stabilized plasma gun to form robust self-supporting bodies with a photocatalytically active surface. Agglomerated nanometric powder was used as a feedstock. In one case argon was used as a powder-feeding as well as coating-cooling gas whereas in the other case nitrogen was used. Stainless steel was used as a substrate and the coatings were released after the cooling. Over one millimeter thick self-supporting bodies were studied by XRD, HR-TEM, XPS, Raman spectroscopy, UV-VIS spectrophotometry and photocatalytic tests. Selected tests were done at the surface as well as at the bottom side representing the contact surface with the substrate during the spray process. Porosity was studied by image analysis on polished cross sections where also microhardness was measured. The dominant phase present in the sprayed samples was rutile, whereas anatase was only a minor component. The hydrogen content in the nitrogen-assisted coating was higher, but the character of the optical absorption edge remained the same for both samples. Photoelectron spectroscopy revealed differences in the character of the O1s peak between both samples. The photocatalytic activity was tested by decomposition of acetone at UV illumination, whereas also the end products—CO and CO2—were monitored. The nitrogen-assisted coating was revealed as a more efficient photocatalyst. Certain aspects of a thermal post-treatment on the coatings are discussed as well. Color and electrical conductivity are markedly changed at annealing at 760 °C, whereas only very small changes of the as-sprayed coating character correspond to annealing at 500 °C.

  11. Influence des potentiels d'interaction sur les proprits de transport des plasmas thermiques : exemple d'application le plasma argon hydrogne

    E-print Network

    Paris-Sud XI, Université de

    cross-sections. The plasma composition (in LTE) is calculated at atmospheric pressure by the free energy are compared to those of the literature. Revue Phys. Appl. 18 (1983) 51-66 JANVIER 1983, PAGE Classification des opérations de métallurgie extractive [5-8] et à la production de gaz réducteurs ou oxydants à

  12. ESCAMPIG XXII, Greifswald, Germany, July 15-19, 2014 Analyses of plasma spheroids in dusty plasma by RF discharge in argon

    E-print Network

    Boyer, Edmond

    by Optical Emission Spectroscopy. They are also studied for their interactions with the particle cloud formed, and the other one near the bottom electrode. In our vacuum chamber, we have only one set of spheroids go into the particle cloud. Fig. 1: Plasma spheroids in the discharge. The particle cloud

  13. Measurement of electron temperatures of Argon Plasmas in a High-Density Inductively-Coupled Remote Plasma System by Langmuir Probe and Optical-Emission Spectroscopy

    Microsoft Academic Search

    A. Boogaard; A. Y. Kovalgin; A. A. I. Aarnink; R. A. M. Wolters; J. Holleman; I. Brunets; J. Schmitz

    2006-01-01

    We measured electron density and electron energy distribution function (EEDF) in our reactor by a Langmuir probe. The EEDF of Ar plasma in the reactor could largely be described by the Maxwell-Boltzmann distribution function, but it also contained a fraction (~10-3) of electrons which were much faster (20-40 eV). The peak of the fast-electron tail shifted from E ~ 35

  14. Powder evolution at low powers in silane-argon discharge

    SciTech Connect

    Chaudhuri, P.; Gupta, N. Dutta; Bhaduri, A.; Longeaud, C.; Vignoli, S.; Marty, O. [Energy Research Unit, Indian Association for the Cultivation of Science, Jadavpur, Calcutta 700032 (India); Laboratoire de Genie Electrique de Paris, Unite Mixte de Recherche (UMR) 8507 Centre National de la Recherche Scientifique (CNRS), Ecole Superieure d'Electricite, Universites Paris VI et XI, 11 rue Joliot Curie, Plateau de Moulon, 91190, Gif sur Yvette (France); Laboratoire de Physique de la Matiere Condensee et Nanostructures, Unite Mixte de Recherche (UMR) 5586 Centre National de la Recherche Scientifique (CNRS), Universite Claude Bernard, Batiment Leon Brillouin, La Doua, 69622 Villeurbanne Cedex (France); Laboratoire d'Electronique, Nanotechnologies, Capteurs (EA 3730), Universite Claude Bernard, Batiment Leon Brillouin, La Doua, 69622 Villeurbanne Cedex (France)

    2005-08-15

    Powder formation in a 13.56-MHz radio frequency (rf) capacitive glow discharge plasma of silane-argon mixture has been studied by in situ laser light-scattering measurements. The rf power density (P{sub rf}) was varied from 18 to 53 mW/cm{sup 2}. At high P{sub rf} the light scattering occurs all along the discharge and extends even beyond the exit end of the electrodes toward the pumping system. With decreasing P{sub rf} the maximum intensity of the light scattering decreases and the scattering zone shrinks and moves toward the exit end. With P{sub rf}{approx_equal}20 mW/cm{sup 2} a very bright scattering zone only a few centimeters wide appears located at the electrodes outlet. The powders studied by transmission electron microscopy did not show a drastic decrease of their sizes with P{sub rf} though clear coagulation of small particles is observed at high P{sub rf}. In this paper we have tried to link the laser light-scattering evolution with P{sub rf} to various parameters such as the microstructure factor, the deposition rate, the electron mobilityxlifetime product, the density of states, and the minority-carriers diffusion length of the films in an attempt to link the effect the evolution of powder formation to the films properties.

  15. Argon/UF6 plasma exhaust gas reconstitution experiments using preheated fluorine and on-line diagnostics. [fissioning uranium plasma core reactor design

    NASA Technical Reports Server (NTRS)

    Roman, W. C.

    1979-01-01

    The feasibility of employing a flowing, high-temperature, pure fluorine/UF6 regeneration system to efficiently convert a large fraction of the effluent plasma exhaust back to pure UF6 was demonstrated. The custom built T.O.F. mass spectrometer sampling system permitted on-line measurements of the UF6 concentration at different locations in the exhaust system. Negligible amounts ( 100 ppm) of UF6 were detected in the axial bypass exhaust duct and the exhaust ducts downstream of the cryogenic trap system used to collect the UF6, thus verifying the overall system efficiency over a range of operating conditions. Use of a porous Monel duct as part of the exhaust duct system, including provision for injection of pure fluorine, provided a viable technique to eliminate uranium compound residue on the inside surface of the exhaust ducts. Typical uranium compound mass deposition per unit area of duct was 2 micron g/sq cm. This porous duct technique is directly applicable to future uranium compound transfer exhaust systems. Throughout these experiments, additional basic data on the corrosion aspects of hot, pressurized UF6/fluorine were also accumulated.

  16. Overview of the coagulation system

    PubMed Central

    Palta, Sanjeev; Saroa, Richa; Palta, Anshu

    2014-01-01

    Coagulation is a dynamic process and the understanding of the blood coagulation system has evolved over the recent years in anaesthetic practice. Although the traditional classification of the coagulation system into extrinsic and intrinsic pathway is still valid, the newer insights into coagulation provide more authentic description of the same. Normal coagulation pathway represents a balance between the pro coagulant pathway that is responsible for clot formation and the mechanisms that inhibit the same beyond the injury site. Imbalance of the coagulation system may occur in the perioperative period or during critical illness, which may be secondary to numerous factors leading to a tendency of either thrombosis or bleeding. A systematic search of literature on PubMed with MeSH terms ‘coagulation system, haemostasis and anaesthesia revealed twenty eight related clinical trials and review articles in last 10 years. Since the balance of the coagulation system may tilt towards bleeding and thrombosis in many situations, it is mandatory for the clinicians to understand physiologic basis of haemostasis in order to diagnose and manage the abnormalities of the coagulation process and to interpret the diagnostic tests done for the same. PMID:25535411

  17. Production of high purity argon

    Microsoft Academic Search

    J. A. Hopkins; R. M. McGuinnes; R. Agrawal; S. L. Feldman

    1991-01-01

    This patent describes a process for the production of high purity argon. It comprises: recovering an argon-enriched sidestream from a low pressure column of a cryogenic air separation distillation system comprising a high pressure column, the low pressure column, an argon sidearm column, and a main heat exchanger; passing the argon-enriched sidestream into the argon sidearm column and withdrawing therefrom

  18. RADIATION KINETICS AND CHEMICAL REACTIVITY OF BARRIER DISCHARGES IN HUMID ARGON

    E-print Network

    Boyer, Edmond

    RADIATION KINETICS AND CHEMICAL REACTIVITY OF BARRIER DISCHARGES IN HUMID ARGON K.V. Kozlov1,a , E discharge in flowing humid argon at atmospheric pressure. Concentrations of two stable reaction products of H2O decomposition (H2 and O2) in argon plasma were determined experimentally as functions

  19. The Discovery of Argon

    Microsoft Academic Search

    G. H. Darwin

    1904-01-01

    IN your translation of Prof. Mendeléeff's interesting paper on the chemical elements (November 17, p. 94) I see that he attributes the discovery of argon and its congeners to Ramsay. Am I not right in believing that it was Lord Rayleigh who discovered argon, and that it was he who gave that impulse to chemistry which Sir William Ramsay has

  20. Autoantibodies to coagulation factors: from pathophysiology to diagnosis and therapy.

    PubMed

    Cugno, Massimo; Gualtierotti, Roberta; Tedeschi, Alberto; Meroni, Pier Luigi

    2014-01-01

    Autoantibodies may develop against coagulation factors altering their function or promoting their rapid clearance. In non-congenitally deficient patients, they are usually in association with autoimmune diseases, malignancies, pregnancy or advanced age. The possible development of coagulation factor autoantibodies should be considered when a patient presents with bleeding symptoms without any prior bleeding diathesis. The most common disorder associated with coagulation factor autoantibodies is acquired factor VIII deficiency, which is characterized by hemorrhages involving soft tissues, muscles and skin; hemarthroses are less frequent than in the inherited form. Acquired deficiencies of von Willebrand factor and factor XIII due to autoantibodies are emerging conditions. Autoantibodies to the other coagulation factors may be associated with a wide spectrum of clinical manifestations ranging from minimal or no bleeding to life-threatening conditions. The diagnostic approach begins with global coagulation tests: prothrombin time (PT) and activated partial thromboplastin time (aPTT). In case of prolonged times, mixing studies (typically using normal plasma in a 1:1 proportion) should be performed. Specific factor and inhibitor assays, assessment of lupus anticoagulant and eventually enzyme immunoassays for specific anti-factor antibodies complete the evaluation. A prompt diagnosis of specific coagulation factor inhibitors is mandatory for starting an appropriate treatment aimed at overcoming the deficient factor, in case of bleeding, and, if possible, at the suppression of the autoantibody's production. PMID:23954454

  1. Numerical Modeling of Plasmas in which Nanoparticles Nucleate and Grow

    NASA Astrophysics Data System (ADS)

    Agarwal, Pulkit

    Dusty plasmas refer to a broad category of plasmas. Plasmas such as argon-silane plasmas in which particles nucleate and grow are widely used in semiconductor processing and nanoparticle manufacturing. In such dusty plasmas, the plasma and the dust particles are strongly coupled to each other. This means that the presence of dust particles significantly affects the plasma properties and vice versa. Therefore such plasmas are highly complex and they involve several interesting phenomena like nucleation, growth, coagulation, charging and transport. Dusty plasma afterglow is equally complex and important. Especially, residual charge on dust particles carries special significance in several industrial and laboratory situations and it has not been well understood. A 1D numerical model was developed of a low-pressure capacitively-coupled plasma in which nanoparticles nucleate and grow. Polydispersity of particle size distributions can be important in such plasmas. Sectional method, which is well known in aerosol literature, was used to model the evolving particle size and charge distribution. The numerical model is transient and one-dimensional and self consistently accounts for nucleation, growth, coagulation, charging and transport of dust particles and their effect on plasma properties. Nucleation and surface growth rates were treated as input parameters. Results were presented in terms of particle size and charge distribution with an emphasis on importance of polydispersity in particle growth and dynamics. Results of numerical model were compared with experimental measurements of light scattering and light emission from plasma. Reasonable qualitative agreement was found with some discrepancies. Pulsed dusty plasma can be important for controlling particle production and/or unwanted particle deposition. In this case, it is important to understand the behavior of the particle cloud during the afterglow following plasma turn-off. Numerical model was modified to self consistently simulate the dynamics and charging of particles during afterglow. It was found that dusty plasma afterglow is dominated by different time scales for electron and ion dynamics. Particle size and charge distribution changes significantly during the afterglow. Finally, a simplified chemistry model was included in dusty plasma numerical model to simulate the dynamics of argon-silane dusty plasma. The chemistry model treats silane dissociation and reactions of silicon hydrides containing up to two silicon atoms. The nucleation rate is equated to rate of formation of anions containing two Si atoms, and a heterogeneous reaction model is used to model particle surface growth. Evolution of particle size and concentration is explained and the importance of variable surface growth rate and nucleation rate is discussed.

  2. Brain neoplasms and coagulation.

    PubMed

    Magnus, Nathalie; D'Asti, Esterina; Garnier, Delphine; Meehan, Brian; Rak, Janusz

    2013-11-01

    Brain vasculature is uniquely programmed to protect central nervous system tissues and respond to their metabolic demands. These functions are subverted during the development of primary and metastatic brain tumors, resulting in vascular perturbations that are thought to contribute to progression and comorbidities of the underlying disease, including thrombosis and hemorrhage. Chronic activation of the coagulation system is particularly obvious in glioblastoma multiforme (GBM), where intratumoral vasoocclusive thrombosis may contribute to hypoxia, pseudopalisading necrosis, and angiogenesis. GBM is also associated with spontaneous or iatrogenic bleeding, and the emission of circulating procoagulants implicated in the unusually high risk of peripheral venous thromboembolism. Tissue factor (TF) expression is elevated in several types of brain tumors, including adult and pediatric GBM, as is the production of TF-containing microparticles (TF-MPs). Both TF expression and its vesicular emission are regulated by tumor microenvironment (e.g., hypoxia), in concert with activated oncogenic and growth factor pathways (RAS, EGFR, MET), as well as the loss of tumor suppressor gene activity (PTEN). Discovery of distinct oncogenic networks led to recognition of unique molecular subtypes within brain tumors, of which GBM (proneural, neural, classical, and mesenchymal), and medulloblastoma (SHH, WNT, group 3, and group 4) exhibit subtype-specific composition of the tumor coagulome. It remains to be established whether mechanisms of thrombosis and biological effects of coagulation in brain tumors are also subtype specific. In this regard, TF pathway represents a paradigm, and its impact on tumor dormancy, inflammation, angiogenesis, formation of cancer stem cell niches, and dissemination is a subject of considerable interest. However, establishing the extent to which TF and TF-MPs contribute to pathogenesis and thromboembolic disease in the context of primary and secondary brain tumors may require molecular stratification of patient populations. We suggest that a better understanding of these molecular linkages may pave the way to a more effective (targeted) therapy, prophylaxis, adjunctive use of anticoagulants, and other agents able to modulate interactions between brain tumors and the coagulation system. PMID:24108471

  3. In-flight thermal treatment of soda-lime-silica glass powders for glass production by argon–oxygen induction thermal plasmas

    Microsoft Academic Search

    M. Mofazzal Hossain; Yaochun Yao; Takayuki Watanabe; Fuji Funabiki; Tetsuji Yano

    2009-01-01

    In order to investigate the plasma–particle energy exchange dynamics and optimize the plasma discharge and particle parameters during in-flight thermal treatment of soda-lime-silica glass powders, a plasma–particle interaction model was developed. This model solved the conservation equations to predict the plasma temperature and flow fields, and then calculated the injected individual particle trajectories and temperature histories, and the particle source

  4. Microfluidics and Coagulation Biology

    PubMed Central

    Colace, Thomas V.; Tormoen, Garth W.

    2014-01-01

    The study of blood ex vivo can occur in closed or open systems, with or without flow. Microfluidic devices facilitate measurements of platelet function, coagulation biology, cellular biorheology, adhesion dynamics, pharmacology, and clinical diagnostics. An experimental session can accommodate 100s to 1000s of unique clotting events. Using microfluidics, thrombotic events can be studied on defined surfaces of biopolymers, matrix proteins, and tissue factor under constant flow rate or constant pressure drop conditions. Distinct shear rates can be created on a device with a single perfusion pump. Microfluidic devices facilitated the determination of intraluminal thrombus permeability and the discovery that platelet contractility can be activated by a sudden decrease in flow. Microfluidics are ideal for multicolor imaging of platelets, fibrin, and phosphatidylserine and provide a human blood analog to the mouse injury models. Overall, microfluidic advances offer many opportunities for research, drug testing under relevant hemodynamic conditions, and clinical diagnostics. PMID:23642241

  5. Thermophoretically modified aerosol brownian coagulation.

    PubMed

    Arias-Zugasti, Manuel; Rosner, Daniel E

    2011-08-01

    A theory of aerosol coagulation rates resulting from continuum-regime brownian coagulation in the presence of size-dependent particle thermophoresis is developed and explored here. We are motivated by a wide variety of applications in which particle brownian coagulation occurs in a nonisothermal gas where differential thermophoretic drift contributes to, but does not dominate, the encounter frequency between suspended spherical particles (e.g., mist droplets) of different sizes. We employ a Smoluchowski-like population-balance to demonstrate the relative roles of brownian diffusion and thermophoresis in shaping the short and long time (asymptotic or "coagulation-aged") mist-droplet size distribution (DSD) function. To carry out these combined-mechanism DSD-evolution calculations we developed a rational "coupled" coagulation rate constant (allowing for simultaneous brownian diffusion and relative thermophoretic drift) rather than simply adding the relevant individual coagulation "kernels." Dimensionless criteria are provided to facilitate precluding other coagulation mechanisms not considered here (such as simultaneous sedimentation or Marangoni-flow-induced mist-droplet phoresis) and potential complications not included in the present model [as finite-rate coalescence, initial departures from the continuum (Stokes drag-) limit, and even dense (nonideal) vapor effects]. PMID:21928988

  6. Investigation of nonequilibrium in the initial region of single and binary phase submerged jets of argon

    Microsoft Academic Search

    M. V. Zake; V. E. Liepinia

    1976-01-01

    Experiments were conducted to investigate the axial temperature distribution of single and two phase jets of argon plasma with particles of tungsten and titanium. The plasma was generated in an plasmatron whose arc current density varied from 100 to 300 amps producing temperature variations of argon beyond the nozzle section in the range 2000-5000 K. It was found that in

  7. REMOVING TRIHALOMETHANE PRECURSORS BY COAGULATION

    EPA Science Inventory

    The removal of trihalomethane precursors by coagulation was studied with low turbidity, low alkalinity waters containing high levels of aquatic humic matter. Jar tests were conducted with synthetic and natural waters using alum, high-molecular-weight polymers, cationic polymers, ...

  8. Depleted Argon from Underground Sources

    SciTech Connect

    Back, H. O.; Galbiati, C.; Goretti, A.; Loer, B.; Montanari, D.; Mosteiro, P. [Department of Physics, Princeton University, Jadwin Hall, Princeton, NJ 08544 (United States); Alexander, T.; Alton, A.; Rogers, H. [Augustana College, Physics Department, 2001 South Summit Ave., Sioux Fall, SD 57197 (United States); Kendziora, C.; Pordes, S. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)

    2011-04-27

    Argon is a strong scintillator and an ideal target for Dark Matter detection; however {sup 39}Ar contamination in atmospheric argon from cosmic ray interactions limits the size of liquid argon dark matter detectors due to pile-up. Argon from deep underground is depleted in {sup 39}Ar due to the cosmic ray shielding of the earth. In Cortez, Colorado, a CO{sub 2} well has been discovered to contain approximately 600 ppm of argon as a contamination in the CO{sub 2}. We first concentrate the argon locally to 3% in an Ar, N{sub 2}, and He mixture, from the CO{sub 2} through chromatographic gas separation, and then the N{sub 2} and He will be removed by continuous distillation to purify the argon. We have collected 26 kg of argon from the CO{sub 2} facility and a cryogenic distillation column is under construction at Fermilab to further purify the argon.

  9. Roles of argon seeding in energy confinement and pedestal structure in JT-60U

    NASA Astrophysics Data System (ADS)

    Urano, H.; Nakata, M.; Aiba, N.; Kubo, H.; Honda, M.; Hayashi, N.; Yoshida, M.; Kamada, Y.; the JT-60 Team

    2015-03-01

    The mechanism of improving energy confinement with argon seeding at high density has been investigated in JT-60U. Better confinement is sustained at high density by argon seeding accompanied by higher core and pedestal temperatures. The electron density profiles become flatter with increasing density in conventional H-mode plasmas, whereas peaked density profiles are maintained with argon seeding. Density peaking and dilution effects lower the pedestal density at a given averaged density. The pedestal density in the argon seeded plasmas, which is lower than that in plasmas with deuterium puff, enables the pedestal temperature to be higher, whereas the increase in the pedestal pressure with argon seeding is small. High pedestal temperature is a boundary condition for high core temperature through profile stiffness, which leads to better confinement with argon seeding. The density peaking is a key factor of sustaining better confinement in argon seeded H-mode plasmas. The radiative loss power density is predominantly enhanced in the edge region by argon puff. The role of argon seeding in the pedestal characteristics has also been examined. The pedestal width becomes larger continuously with edge collisionality, but is nearly independent of the presence of argon seeding.

  10. SERIES ''INTERVENTIONAL PULMONOLOGY'' Edited by J.P. Janssen, M. Noppen and K.F. Rabe Number 1 in this Series Therapeutic bronchoscopy with immediate effect: laser, electrocautery, argon plasma coagulation and stents

    Microsoft Academic Search

    C. T. Bolliger; T. G. Sutedja; J. Strausz; L. Freitag; Lungenklinik Hemer

    Minimally invasive diagnostic and therapeutic approaches in medicine have been applied for a more selective and tailored approach to reduce patients' morbidity and mortality. The efficacy of interventional pulmonology for palliation of patients with central airways obstruction has been established and its curative potential for intralesional treatment of early cancer has raised great interest in current screening programmes. This is

  11. Spectroscopic characterization of femtosecond laser filament in argon gas

    SciTech Connect

    Liu, W.; Bernhardt, J.; Theberge, F.; Chin, S. L.; Chateauneuf, M.; Dubois, J. [Institute of Modern Optics, Nankai University, Key Laboratory of Opto-electronic Information Science and Technology, Education Ministry of China, Tianjin 300071 (China); Centre d'Optique, Photonique et Laser (COPL) and Departement de physique, de genie physique et d'optique, Universite Laval, Quebec, Quebec G1K 7P4 (Canada); Defence Research and Development Canada--Valcartier, 2459 Pie-XI Blvd. North, Quebec, Quebec, G3J 1X5 Canada (Canada)

    2007-08-01

    We report a spectroscopic approach to measure the plasma density and electron temperature inside a filament created by an intense femtosecond laser pulse in atmospheric pressure argon gas. The technique relies on the proportionality between the Stark broadened argon fluorescence line width due to electron impact and the plasma density, while the electron temperature is determined from the well known Boltzmann plot. The obtained maximum plasma density is about 5.5x10{sup 16} cm{sup -3}, and the electron temperature is about 5800 K. Our method provides a promising and convenient way to characterize the filament for further understanding the fundamental physics and potential applications of filamentation.

  12. SLD liquid argon calorimeter

    SciTech Connect

    Vella, E.

    1992-10-01

    The liquid argon calorimeter (LAC) of the SLD detector is a parallel plate -- liquid argon sampling calorimeter, used to measure particle energies in Z[sup 0] decays at the Stanford Linear Collider. The LAC module design is based on a unique projective tower structure, in which lead plates and segmented lead tiles serve both as absorbers and electrodes. The LAC front end electronics incorporates several novel features, including extensive multiplexing and optical fiber readout, which take advantage of the low SLC beam crossing frequency. The operational performance of the LAC during the recently completed SLD physics run (which recorded over 10,000 Z[sup 0] events) is discussed.

  13. SLD liquid argon calorimeter

    SciTech Connect

    Vella, E.; SLD Collaboration

    1992-10-01

    The liquid argon calorimeter (LAC) of the SLD detector is a parallel plate -- liquid argon sampling calorimeter, used to measure particle energies in Z{sup 0} decays at the Stanford Linear Collider. The LAC module design is based on a unique projective tower structure, in which lead plates and segmented lead tiles serve both as absorbers and electrodes. The LAC front end electronics incorporates several novel features, including extensive multiplexing and optical fiber readout, which take advantage of the low SLC beam crossing frequency. The operational performance of the LAC during the recently completed SLD physics run (which recorded over 10,000 Z{sup 0} events) is discussed.

  14. One-step argon/nitrogen binary plasma jet irradiation of Li4Ti5O12 for stable high-rate lithium ion battery anodes

    NASA Astrophysics Data System (ADS)

    Lan, Chun-Kai; Chuang, Shang-I.; Bao, Qi; Liao, Yen-Ting; Duh, Jenq-Gong

    2015-02-01

    Atmospheric pressure Ar/N2 binary plasma jet irradiation has been introduced into the manufacturing process of lithium ions batteries as a facile, green and scalable post-fabrication treatment approach, which enhanced significantly the high-rate anode performance of lithium titanate (Li4Ti5O12). Main emission lines in Ar/N2 plasma measured by optical emission spectroscopy reveal that the dominant excited high-energy species in Ar/N2 plasma are N2*, N2+, N? and Ar?. Sufficient oxygen vacancies have been evidenced by high resolution X-ray photoelectron spectroscopy analysis and Raman spectra. Nitrogen doping has been achieved simultaneously by the surface reaction between pristine Li4Ti5O12 particles and chemically reactive plasma species such as N? and N2+. The variety of Li4Ti5O12 particles on the surface of electrodes after different plasma processing time has been examined by grazing incident X-Ray diffraction. Electrochemical impedance spectra (EIS) confirm that the Ar/N2 atmospheric plasma treatment facilitates Li+ ions diffusion and reduces the internal charge-transfer resistance. The as-prepared Li4Ti5O12 anodes exhibit a superior capacity (132 mAh g-1) and excellent stability with almost no capacity decay over 100 cycles under a high C rate (10C).

  15. Novel peptides that inhibit heparanase activation of the coagulation system.

    PubMed

    Axelman, E; Henig, I; Crispel, Y; Attias, J; Li, J-P; Brenner, B; Vlodavsky, I; Nadir, Y

    2014-09-01

    Heparanase is implicated in cell invasion, tumour metastasis and angiogenesis. It forms a complex and enhances the activity of the blood coagulation initiator - tissue factor (TF). We describe new peptides derived from the solvent accessible surface of TF pathway inhibitor 2 (TFPI-2) that inhibit the heparanase procoagulant activity. Peptides were evaluated in vitro by measuring activated coagulation factor X levels and co-immunoprecipitation. Heparanase protein and/or lipopolysaccharide (LPS) were injected intra-peritoneally and inhibitory peptides were injected subcutaneously in mouse models. Plasma was analysed by ELISA for thrombin-antithrombin complex (TAT), D-dimer as markers of coagulation activation, and interleukin 6 as marker of sepsis severity. Peptides 5, 6, 7, 21 and 22, at the length of 11-14 amino acids, inhibited heparanase procoagulant activity but did not affect TF activity. Injection of newly identified peptides 5, 6 and 7 significantly decreased or abolished TAT plasma levels when heparanase or LPS were pre-injected, and inhibited clot formation in an inferior vena cava thrombosis model. To conclude, the solvent accessible surface of TFPI-2 first Kunitz domain is involved in TF/heparanase complex inhibition. The newly identified peptides potentially attenuate activation of the coagulation system induced by heparanase or LPS without predisposing to significant bleeding tendency. PMID:25030319

  16. Influence of argon plasma on the deposition of Al2O3 film onto the PET surfaces by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Edy, Riyanto; Huang, Xiaojiang; Guo, Ying; Zhang, Jing; Shi, Jianjun

    2013-02-01

    In this paper, polyethyleneterephthalate (PET) films with and without plasma pretreatment were modified by atomic layer deposition (ALD) and plasma-assisted atomic layer deposition (PA-ALD). It demonstrates that the Al2O3 films are successfully deposited onto the surface of PET films. The cracks formed on the deposited Al2O3 films in the ALD, plasma pretreated ALD, and PA-ALD were attributed to the energetic ion bombardment in plasmas. The surface wettability in terms of water contact angle shows that the deposited Al2O3 layer can enhance the wetting property of modified PET surface. Further characterizations of the Al2O3 films suggest that the elevated density of hydroxyl -OH group improve the initial growth of ALD deposition. Chemical composition of the Al2O3-coated PET film was characterized by X-ray photoelectron spectroscopy, which shows that the content of C 1 s reduces with the growing of O 1 s in the Al2O3-coated PET films, and the introduction of plasma in the ALD process helps the normal growth of Al2O3 on PET in PA-ALD.

  17. Influence of argon plasma on the deposition of Al2O3 film onto the PET surfaces by atomic layer deposition

    PubMed Central

    2013-01-01

    In this paper, polyethyleneterephthalate (PET) films with and without plasma pretreatment were modified by atomic layer deposition (ALD) and plasma-assisted atomic layer deposition (PA-ALD). It demonstrates that the Al2O3 films are successfully deposited onto the surface of PET films. The cracks formed on the deposited Al2O3 films in the ALD, plasma pretreated ALD, and PA-ALD were attributed to the energetic ion bombardment in plasmas. The surface wettability in terms of water contact angle shows that the deposited Al2O3 layer can enhance the wetting property of modified PET surface. Further characterizations of the Al2O3 films suggest that the elevated density of hydroxyl -OH group improve the initial growth of ALD deposition. Chemical composition of the Al2O3-coated PET film was characterized by X-ray photoelectron spectroscopy, which shows that the content of C 1s reduces with the growing of O 1s in the Al2O3-coated PET films, and the introduction of plasma in the ALD process helps the normal growth of Al2O3 on PET in PA-ALD. PMID:23413804

  18. Thermophysical properties of argon

    SciTech Connect

    Jaques, A.

    1988-02-01

    The entire report consists of tables of thermodynamic properties (including sound velocity, thermal conductivity and diffusivity, Prandtl number, density) of argon at 86 to 400/degree/K, in the form of isobars over 0.9 to 100 bars. (DLC)

  19. Coagulation parameters in inflammatory bowel disease

    PubMed Central

    Dolapcioglu, Can; Soylu, Aliye; Kendir, Tulin; Ince, Ali Tuzun; Dolapcioglu, Hatice; Purisa, Sevim; Bolukbas, Cengiz; Sokmen, Haci Mehmet; Dalay, Remzi; Ovunc, Oya

    2014-01-01

    Thromboembolic events represent a major cause of morbidity and mortality in patients with inflammatory bowel disease and they may occur both at the gastrointestinal tract and at extraintestinal sites. This study aimed to examine the alterations in coagulation parameters involved at different steps of hemostasis in patients with Crohn’s disease and ulcerative colitis, in comparison with healthy individuals. Fifty-one patients with inflammatory bowel disease and 26 healthy controls were included in this study. Plasma levels of PT, APTT, AT III, plasminogen, fibrinogen, D-dimer, factor V, factor VIII, protein C, protein S, and APCR were measured and factor V Leiden mutation was examined in both patients and controls. Two patients with ulcerative colitis had a history of previous thromboembolic event. Inflammatory bowel disease was associated with significantly higher levels of fibrinogen, PT, factor V, factor VIII, plasminogen and thrombocyte. Protein S, fibrinogen, plasminogen and thrombocyte levels were associated with disease activity, depending on the type of the disease (Crohn’s disease or ulcerative colitis). The coagulation abnormalities detected in this study seems to be a secondary phenomena resulting from the disease process, which is more likely to be associated with a multitude of factors rather than a single abnormality. PMID:24995109

  20. Characteristics of atmospheric-pressure, radio-frequency glow discharges operated with argon added ethanol

    NASA Astrophysics Data System (ADS)

    Sun, Wen-Ting; Li, Guo; Li, He-Ping; Bao, Cheng-Yu; Wang, Hua-Bo; Zeng, Shi; Gao, Xing; Luo, Hui-Ying

    2007-06-01

    Rf, atmospheric-pressure glow discharge (APGD) plasmas with bare metal electrodes have promising prospects in the fields of plasma-aided etching, thin film deposition, disinfection and sterilization, etc. In this paper, the discharge characteristics are presented for the rf APGD plasmas generated with pure argon or argon-ethanol mixture as the plasma-forming gas and using water-cooled, bare copper electrodes. The experimental results show that the breakdown voltage can be reduced significantly when a small amount of ethanol is added into argon, probably due to the fact that the Penning ionization process is involved, and a pure ?-mode discharge can be produced more easily with the help of ethanol. The uniformity of the rf APGDs of pure argon or argon-ethanol mixtures using bare metallic electrodes is identified with the aid of the intensified charge coupled device images.

  1. Emission spectroscopy combined with a single and a double probe in low-pressure inductively-coupled nitrogen-argon plasmas

    NASA Astrophysics Data System (ADS)

    Park, Jae Min; Song, Min A.; Chung, T. H.

    2012-08-01

    Low-pressure inductively coupled N2-Ar plasmas have been studied to investigate the effects of operating parameters, including the Ar content, applied power, and gas pressure. By means of optical emission spectroscopy and single and double Langmuir probe diagnostic techniques, the evolutions of the plasma density, the electron temperature, and the N2 +, N2, N, and Ar emission lines have been investigated with a discussion of a spatially-averaged global model. From the emission spectra, the ratios of the concentrations of species of interest, and the rotational and the vibrational temperatures of the nitrogen molecules are obtained for various discharge conditions. The rotational and the vibrational temperatures of N2 are found to increase with increasing applied power, pressure, and Ar content, thus making nitrogen plasmas more reactive.

  2. Optimization of microalgae coagulation process using chitosan

    Microsoft Academic Search

    A. L. Ahmad; N. H. Mat Yasin; C. J. C. Derek; J. K. Lim

    2011-01-01

    Here, we report on the harvesting of microalgae cells by coagulation using chitosan and the optimization of this process. Chitosan is a natural and environmentally friendly biopolymer created by the extensive deacetylation of chitin from shrimp, crab and crawfish. Although conventional chemical coagulants such as alum may have negative impacts on human health, the use of chitosan as coagulant is

  3. Molecular intercommunication between the complement and coagulation systems.

    PubMed

    Amara, Umme; Flierl, Michael A; Rittirsch, Daniel; Klos, Andreas; Chen, Hui; Acker, Barbara; Brückner, Uwe B; Nilsson, Bo; Gebhard, Florian; Lambris, John D; Huber-Lang, Markus

    2010-11-01

    The complement system as well as the coagulation system has fundamental clinical implications in the context of life-threatening tissue injury and inflammation. Associations between both cascades have been proposed, but the precise molecular mechanisms remain unknown. The current study reports multiple links for various factors of the coagulation and fibrinolysis cascades with the central complement components C3 and C5 in vitro and ex vivo. Thrombin, human coagulation factors (F) XIa, Xa, and IXa, and plasmin were all found to effectively cleave C3 and C5. Mass spectrometric analyses identified the cleavage products as C3a and C5a, displaying identical molecular weights as the native anaphylatoxins C3a and C5a. Cleavage products also exhibited robust chemoattraction of human mast cells and neutrophils, respectively. Enzymatic activity for C3 cleavage by the investigated clotting and fibrinolysis factors is defined in the following order: FXa > plasmin > thrombin > FIXa > FXIa > control. Furthermore, FXa-induced cleavage of C3 was significantly suppressed in the presence of the selective FXa inhibitors fondaparinux and enoxaparin in a concentration-dependent manner. Addition of FXa to human serum or plasma activated complement ex vivo, represented by the generation of C3a, C5a, and the terminal complement complex, and decreased complement hemolytic serum activity that defines exact serum concentration that results in complement-mediated lysis of 50% of sensitized sheep erythrocytes. Furthermore, in plasma from patients with multiple injuries (n = 12), a very early appearance and correlation of coagulation (thrombin-antithrombin complexes) and the complement activation product C5a was found. The present data suggest that coagulation/fibrinolysis proteases may act as natural C3 and C5 convertases, generating biologically active anaphylatoxins, linking both cascades via multiple direct interactions in terms of a complex serine protease system. PMID:20870944

  4. Activation of the coagulation cascade in C1-inhibitor deficiencies.

    PubMed

    Cugno, M; Cicardi, M; Bottasso, B; Coppola, R; Paonessa, R; Mannucci, P M; Agostoni, A

    1997-05-01

    Activation of the contact and complement systems in C1-inhibitor deficiencies is thought to contribute to the pathogenesis of angioedema attacks by releasing kinins. Trigger stimuli of attacks may also activate coagulation. This is particularly important because experimental data suggest that thrombin, the main enzyme of the coagulation cascade, increases vascular permeability and can thus influence edema formation. We have studied 19 patients with hereditary angioedema (HAE) during remission, 5 HAE patients during acute attacks, and 6 patients with acquired angioedema (AAE) during remission and during seven attacks. Thirty normal subjects, matched for sex and age, served as controls. Generation of thrombin was measured by enzyme-linked immunosorbent assay (ELISA) as plasma levels of the prothrombin fragment 1 + 2 (F1 + 2); the initiators of the tissue factor and contact coagulation pathways were investigated by measuring plasma levels of activated factor VII (FVIIa) coagulometrically and activated factor XII (FXIIa) by ELISA. Cleavage of high molecular weight kininogen (HK) was evaluated by immunoblotting analysis. F1 + 2 was slightly increased during remission and further significantly increased during attacks in both HAE (P = .0115) and AAE. FVIIa and FXIIa, normal during remission, increased strikingly during attacks in both HAE (P = .0022 and P = .0044) and AAE. During remission, cleaved HK was normal in HAE and high in AAE; during attacks it increased in HAE (P = .0008) and remained elevated in AAE. Our data indicate that in C1-inhibitor deficient patients there is increased generation of thrombin during attacks, with signs of activation of both the contact and tissue factor coagulation pathways. In conclusion, C1-inhibitor deficiency, whether hereditary or acquired, has demonstrable activation of the coagulation and kinin-forming cascades during attacks and that thrombin should be considered a possible contributing factor in the pathogenesis of edema in HAE and AAE. PMID:9129025

  5. Coagulation factor XIII: A useful polymorphic genetic marker

    Microsoft Academic Search

    J. B. Graham; C. J. S. Edgell; Hilari Fleming; K. K. Namboodiri; Bronya J. B. Keats; R. C. Elston

    1984-01-01

    The plasmas of two groups of subjects were examined for blood coagulation Factor XIII-A (FXIII-A, F13A) by electrophoresis in agarose using a Tris-EDTA-borate buffer to separate the common variants, F13A*1, F13A*2, and F13A*3. Dimeric subunits were visualized in UV light as monodansyl cadaverine bound to casein at the position of the transglutaminase activity representing F13A. One test group consisted of

  6. 5, 38473872, 2005 Coagulation of

    E-print Network

    Paris-Sud XI, Université de

    Coagulation of combustion generated nanoparticles and their measurement behind vehicle engines: can they play. Aigner DLR Institute of Combustion Technology, Pfaffenwaldring 38­40, 70569 Stuttgart, Germany Received.-H. Grotheer (hh.grotheer@dlr.de) © 2005 Author(s). This work is licensed under a Creative Commons License

  7. The Solar Argon Abundance

    E-print Network

    Katharina Lodders

    2007-10-24

    The solar argon abundance cannot be directly derived by spectroscopic observations of the solar photosphere. The solar Ar abundance is evaluated from solar wind measurements, nucleosynthetic arguments, observations of B stars, HII regions, planetary nebulae, and noble gas abundances measured in Jupiter's atmosphere. These data lead to a recommended argon abundance of N(Ar) = 91,200(+/-)23,700 (on a scale where Si = 10^6 atoms). The recommended abundance for the solar photosphere (on a scale where log N(H) = 12) is A(Ar)photo = 6.50(+/-)0.10, and taking element settling into account, the solar system (protosolar) abundance is A(Ar)solsys = 6.57(+/-)0.10.

  8. Study of nuclear recoils in liquid argon with monoenergetic neutrons

    NASA Astrophysics Data System (ADS)

    Regenfus, C.; Allkofer, Y.; Amsler, C.; Creus, W.; Ferella, A.; Rochet, J.; Walter, M.

    2012-07-01

    In the framework of developments for liquid argon dark matter detectors we assembled a laboratory setup to scatter neutrons on a small liquid argon target. The neutrons are produced mono-energetically (Ekin = 2.45 MeV) by nuclear fusion in a deuterium plasma and are collimated onto a 3" liquid argon cell operating in single-phase mode (zero electric field). Organic liquid scintillators are used to tag scattered neutrons and to provide a time-of-flight measurement. The setup is designed to study light pulse shapes and scintillation yields from nuclear and electronic recoils as well as from alpha particles at working points relevant for dark matter searches. Liquid argon offers the possibility to scrutinise scintillation yields in noble liquids with respect to the population strength of the two fundamental excimer states. Here we present experimental methods and first results from recent data towards such studies.

  9. Argon ion pollution of the magnetosphere

    NASA Technical Reports Server (NTRS)

    Lopez, R. E.

    1985-01-01

    Construction of a Solar Power Satellite (SPS) would require the injection of large quantities of propellant to transport material from Low Earth Orbit (LEO) to the construction site at Geostationary Earth Orbit (GEO). This injection, in the form of approx 10 to the 32nd power, 2 KeV argon ions (and associated electrons) per SPS, is comparable to the content of the plasmasphere (approx 10 to the 31st power ions). In addition to the mass deposited, this represents a considerable injection of energy. The injection is examined in terms of a simple model for the expansion of the beam plasma. General features of the subsequent magnetospheric convection of the argon are also examined.

  10. A Novel Role for Pro-Coagulant Microvesicles in the Early Host Defense against Streptococcus pyogenes

    PubMed Central

    Oehmcke, Sonja; Westman, Johannes; Malmström, Johan; Mörgelin, Matthias; Olin, Anders I.; Kreikemeyer, Bernd; Herwald, Heiko

    2013-01-01

    Previous studies have shown that stimulation of whole blood or peripheral blood mononuclear cells with bacterial virulence factors results in the sequestration of pro-coagulant microvesicles (MVs). These particles explore their clotting activity via the extrinsic and intrinsic pathway of coagulation; however, their pathophysiological role in infectious diseases remains enigmatic. Here we describe that the interaction of pro-coagulant MVs with bacteria of the species Streptococcus pyogenes is part of the early immune response to the invading pathogen. As shown by negative staining electron microscopy and clotting assays, pro-coagulant MVs bind in the presence of plasma to the bacterial surface. Fibrinogen was identified as a linker that, through binding to the M1 protein of S. pyogenes, allows the opsonization of the bacteria by MVs. Surface plasmon resonance analysis revealed a strong interaction between pro-coagulant MVs and fibrinogen with a KD value in the nanomolar range. When performing a mass-spectrometry-based strategy to determine the protein quantity, a significant up-regulation of the fibrinogen-binding integrins CD18 and CD11b on pro-coagulant MVs was recorded. Finally we show that plasma clots induced by pro-coagulant MVs are able to prevent bacterial dissemination and possess antimicrobial activity. These findings were confirmed by in vivo experiments, as local treatment with pro-coagulant MVs dampens bacterial spreading to other organs and improved survival in an invasive streptococcal mouse model of infection. Taken together, our data implicate that pro-coagulant MVs play an important role in the early response of the innate immune system in infectious diseases. PMID:23935504

  11. Argon Purification Reference and Recommendation

    SciTech Connect

    Wu, J.; /Fermilab

    1991-05-23

    This engineering note is a reference for future consideration on the purification of argon. The original concern was for the possibility of argon contamination from components in the cryostats over long-term storage. An argon purification system could also be useful for purifying the contents of the argon dewar. The general conclusion is that most of the systems researched are too expensive at this time, but the recommended choice would be Centorr Furnaces. There were three basic types of purification systems which were to be considered. The first was the molecular sieve. This method would have been the preferred one, because it was claimed that it could purify liquid argon, removing liquid oxygen from the argon. However, none of the commercial companies researched provided this type of purification for use with liquid argon. Most companies said that this type of purification was impossible, and tests at IB-4 confirmed this. The second system contained a copper oxide to remove gaseous oxygen from argon gas. The disadvantage of this system wass that the argon had to be heated to a gas, and then cooled back down to liquid. The third system was similar to the second, except that it used tungsten or another material like titanium. This system also needed to heat the argon to gas, however the advantage of this system was that it supposedly removed all contaminants, that is, everything except for inert gases. Of the three systems, the third is the type manufactured by Centorr Furnaces, which uses a titanium charge.

  12. A simple collisional radiative model for low-pressure argon discharges

    NASA Astrophysics Data System (ADS)

    Zhu, Xi-Ming; Pu, Yi-Kang

    2007-04-01

    A simple collisional-radiative model for low-pressure argon discharges is proposed. Using this model and the measured cross section data from recent literature, the relationship between the electron density and some emission line intensities is investigated, resulting in a semi-empirical formula relating the electron density and the emission intensity ratio of argon lines (from levels 3p and 4p). The electron density determined from this model is compared with that from a Langmuir probe in an inductively coupled argon plasma. The application and validity of this model in other kinds of low-pressure argon plasmas, such as capacitively coupled and helicon plasmas, or in discharges containing both argon and other gases are discussed.

  13. Low-Energy Ionization of Argon Atoms by Argon Atoms

    Microsoft Academic Search

    Howard C. Hayden; Robert C. Amme

    1966-01-01

    A neutral atomic beam has been used to measure the total ionization cross section for argon atoms incident on low-density argon gas. The beam was produced by symmetric charge transfer of argon ions produced in an electron-impact ion source with 20-eV electrons. Beam energies varied from 30 eV (just below threshold for electron production in ground-state atom collisions) to 2900

  14. Numerical analysis of the effect of nitrogen and oxygen admixtures on the chemistry of an argon plasma jet operating at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Van Gaens, W.; Iseni, S.; Schmidt-Bleker, A.; Weltmann, K.-D.; Reuter, S.; Bogaerts, A.

    2015-03-01

    In this paper we study the cold atmospheric pressure plasma jet, called kinpen, operating in Ar with different admixture fractions up to 1% pure {{N}2}, {{O}2} and {{N}2} + {{O}2}. Moreover, the device is operating with a gas curtain of dry air. The absolute net production rates of the biologically active ozone ({{O}3}) and nitrogen dioxide (N{{O}2}) species are measured in the far effluent by quantum cascade laser absorption spectroscopy in the mid-infrared. Additionally, a zero-dimensional semi-empirical reaction kinetics model is used to calculate the net production rates of these reactive molecules, which are compared to the experimental data. The latter model is applied throughout the entire plasma jet, starting already within the device itself. Very good qualitative and even quantitative agreement between the calculated and measured data is demonstrated. The numerical model thus yields very useful information about the chemical pathways of both the {{O}3} and the N{{O}2} generation. It is shown that the production of these species can be manipulated by up to one order of magnitude by varying the amount of admixture or the admixture type, since this affects the electron kinetics significantly at these low concentration levels.

  15. The Argon Geochronology Experiment (AGE)

    NASA Technical Reports Server (NTRS)

    Swindle, T. D.; Bode, R.; Fennema, A.; Chutjian, A.; MacAskill, J. A.; Darrach, M. R.; Clegg, S. M.; Wiens, R. C.; Cremers, D.

    2006-01-01

    This viewgraph presentation reviews the Argon Geochronology Experiment (AGE). Potassium-Argon dating is shown along with cosmic ray dating exposure. The contents include a flow diagram of the Argon Geochronology Experiment, and schematic diagrams of the mass spectrometer vacuum system, sample manipulation mechanism, mineral heater oven, and the quadrupole ion trap mass spectrometer. The Laser-Induced Breakdown Spectroscopy (LIBS) Operation with elemental abundances is also described.

  16. Simultaneous inductively coupled argon plasma emission spectrometer as a multi-element-specific detector for high pressure liquid chromatography: the determination of arsenic, selenium, and phosphorus compounds

    NASA Astrophysics Data System (ADS)

    Irgolic, Kurt J.; Stockton, R. A.; Chakraborti, D.; Beyer, W.

    A Bausch & Lomb-ARL Model 34000 simultaneous inductively coupled plasma (ICP) emission spectrometer was interfaced with a high pressure liquid chromatograph to serve as a multi-element-specific detector. The standard ARL software was modified and a new program written to allow the chromatogram to be displayed graphically on-line. The HPLC-ICP system performance was demonstrated by the separation of arsenite, arsenate, methylarsonic acid, dimethylarsinic acid, phenylarsonic acid, selenite, and phosphate on a reverse-phase column. The detection limit for arsenic is 130 ?g l -1 at 100 ?l injection volumes. The arsenic signals are not dependent on the nature of the arsenic compounds. This HPLC-ICP system allows the quantitative determination of compounds with similar retention times provided they contain different elements determinable by ICP-AES.

  17. Coagulation and fibrinolysis in capybara ( Hydrochaeris hydrochaeris), a close relative of the guinea-pig ( Cavia porcellus)

    Microsoft Academic Search

    D. P. S Leitão; A. C. M Polizello; Z Rothschild

    2000-01-01

    Fibrinolytic and coagulation properties of capybara (Hydrochaeris hydrochaeris, LINNAEUS, 1766) plasma were analysed and the results compared to the guinea-pig (Cavia porcellus), a close relative. Capybara fibrinogen was isolated and fibrinolysis of its plasma was carried out in a homologous system and with bovine fibrin. Undiluted plasma did not have fibrinolytic activity on fibrin plates; euglobulins gave a dose-related response.

  18. Thermophysical properties of multi-shock compressed dense argon

    SciTech Connect

    Chen, Q. F., E-mail: chenqf01@gmail.com; Zheng, J.; Gu, Y. J.; Chen, Y. L.; Cai, L. C. [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, P. O. Box 919-102, Mianyang, Sichuan (China)] [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, P. O. Box 919-102, Mianyang, Sichuan (China); Shen, Z. J. [Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, P. O. Box 8009-26, Beijing 10086 (China)] [Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, P. O. Box 8009-26, Beijing 10086 (China)

    2014-02-21

    In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ?6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models.

  19. A RF Discharge in Argon at Atmospheric Pressure

    Microsoft Academic Search

    Shirshak Dhali; Navin Muthuswamy; Bakul Dave

    2001-01-01

    A dual chamber dischrage is used to create an atmospheric pressure plasma in Argon. The discharge consists of two chambers: one at low pressure (few Torrs) and the other at atmospheric pressure. The chambers are seperated by fused silica window. A RF source(13.56 MHz) is used to create a discharge first in the low pressure chamber which is filled with

  20. Argon Welding Inside A Workpiece

    NASA Technical Reports Server (NTRS)

    Morgan, Gene E.

    1988-01-01

    Canopies convert large hollow workpiece into inert-gas welding chamber. Large manifold serves welding chamber for attachment of liner parts in argon atmosphere. Every crevice, opening and passageway provided with argon-rich environment. Weld defects and oxidation dramatically reduced; also welding time reduced.

  1. Thyroid-associated autoimmune coagulation disorders

    Microsoft Academic Search

    Massimo Franchini; Giuseppe Lippi; Franco Manzato; Pier Paolo Vescovi

    2010-01-01

    Abnormalities of blood coagulation are not rarely observed in patients with thyroid dysfunctions and may range from subclinical\\u000a laboratory abnormalities to clinically significant hemorrhagic or thrombotic complications. In this review, we summarize the\\u000a current knowledge on thyroid-associated autoimmune coagulation disorders (i.e., autoimmune thrombocytopenic purpura, antiphospholipid\\u000a syndrome, and autoantibodies against coagulation factor VIII) and discuss their laboratory characteristics, clinical impact,\\u000a and

  2. Coagulation disorders after traumatic brain injury

    Microsoft Academic Search

    B. S. Harhangi; E. J. O. Kompanje; F. W. G. Leebeek; A. I. R. Maas

    2008-01-01

    Summary  \\u000a Background. Over the past decade new insights in our understanding of coagulation have identified the prominent role of tissue factor.\\u000a The brain is rich in tissue factor, and injury to the brain may initiate disturbances in local and systemic coagulation. We\\u000a aimed to review the current knowledge on the pathophysiology, incidence, nature, prognosis and treatment of coagulation disorders\\u000a following

  3. Activation of coagulation by administration of recombinant factor VIIa elicits interleukin 6 (IL6) and IL8 release in healthy human subjects

    Microsoft Academic Search

    Evert de Jonge; Philip W. Friederich; George P. Vlasuk; William E. Rote; Margaretha B. Vroom; Marcel Levi; Tom van der Poll

    2003-01-01

    The activation of coagulation has been shown to contribute to proinflammatory responses in animal and in vitro experiments. Here we report that the activation of coagulation in healthy human subjects by the administration of recombinant factor VIIa also elicits a small but significant increase in the concentrations of interleukin 6 (IL-6) and IL-8 in plasma. This increase was absent when

  4. Depleted argon from underground sources

    SciTech Connect

    Back, H.O.; /Princeton U.; Alton, A.; /Augustana U. Coll.; Calaprice, F.; Galbiati, C.; Goretti, A.; /Princeton U.; Kendziora, C.; /Fermilab; Loer, B.; /Princeton U.; Montanari, D.; /Fermilab; Mosteiro, P.; /Princeton U.; Pordes, S.; /Fermilab

    2011-09-01

    Argon is a powerful scintillator and an excellent medium for detection of ionization. Its high discrimination power against minimum ionization tracks, in favor of selection of nuclear recoils, makes it an attractive medium for direct detection of WIMP dark matter. However, cosmogenic {sup 39}Ar contamination in atmospheric argon limits the size of liquid argon dark matter detectors due to pile-up. The cosmic ray shielding by the earth means that Argon from deep underground is depleted in {sup 39}Ar. In Cortez Colorado a CO{sub 2} well has been discovered to contain approximately 500ppm of argon as a contamination in the CO{sub 2}. In order to produce argon for dark matter detectors we first concentrate the argon locally to 3-5% in an Ar, N{sub 2}, and He mixture, from the CO{sub 2} through chromatographic gas separation. The N{sub 2} and He will be removed by continuous cryogenic distillation in the Cryogenic Distillation Column recently built at Fermilab. In this talk we will discuss the entire extraction and purification process; with emphasis on the recent commissioning and initial performance of the cryogenic distillation column purification.

  5. The Argon Dark Matter Experiment

    E-print Network

    Christian Regenfus

    2009-12-15

    The ArDM experiment, a 1 ton liquid argon TPC/Calorimeter, is designed for the detection of dark matter particles which can scatter off the spinless argon nucleus, producing nuclear recoils. These events will be discerned by their light to charge ratio, as well as the time structure of the scintillation light. The experiment is presently under construction and commissioning on surface at CERN. Cryogenic operation and light detection performance was recently confirmed in a test run of the full 1 ton liquid argon target under purely calorimetric operation and with a prototype light readout system. This note describes the experimental concept, the main detector components and presents some first results.

  6. Coagulation Abnormalities in the Trauma Patient: The Role of Point-of-Care Thromboelastography

    PubMed Central

    Gonzalez, Eduardo; Pieracci, Fredric M.; Moore, Ernest E.; Kashuk, Jeffry L.

    2015-01-01

    Current recommendations for resuscitation of the critically injured patient are limited by a lack of point-of-care (POC) assessment of coagulation status. Accordingly, the potential exists for indiscriminant blood component administration. Furthermore, although thromboembolic events have been described shortly after injury, the time sequence of post-injury coagulation changes is unknown. Our current understanding of hemostasis has shifted from a classic view, in which coagulation was considered a chain of catalytic enzyme reactions, to the cell-based model (CBM), representing the interplay between the cellular and plasma components of clot formation. Thromboelastography (TEG), a time-sensitive dynamic assay of the viscoelastic properties of blood, closely parallels the CBM, permitting timely, goal-directed restoration of hemostasis via POC monitoring of coagulation status. TEG-based therapy allows for goal-directed blood product administration in trauma, with potential avoidance of the complications resulting from overzealous component administration, as well as the ability to monitor post-injury coagulation status and thromboprophylaxis. This overview addresses coagulation status and thromboprophylaxis management in the trauma patient and the emerging role of POC TEG. PMID:20978993

  7. AUTOSOMAL RECESSIVE DEFICIENCIES OF COAGULATION FACTORS

    Microsoft Academic Search

    F. Peyvandi; R. Asselta; P. M. Mannucci

    2001-01-01

    Deficiencies of coagulation factors that cause a bleeding disorder, other than factor VIII and factor IX, are inherited as autosomal recessive traits and are generally rare, with prevalence in the general population varying between 1 in 500 000 and 1 in 2 000 000. In the last few years, the number of patients with recessively transmitted coagulation deficiencies has increased

  8. The ATLAS Liquid Argon Electromagnetic Calorimeter 1

    E-print Network

    Boyer, Edmond

    The ATLAS Liquid Argon Electromagnetic Calorimeter 1 Pascal Pralavorio (for the ATLAS Liquid Argon operation on the LHC in 2005. The collab- oration has chosen a Liquid Argon electromagnetic calorimeter calorimeter is a sampling calorimeter where absorbers are made of lead and liquid argon is the ionising medium

  9. Argon: performance insulation for shared storage servers

    E-print Network

    Argon: performance insulation for shared storage servers Matthew Wachs, Michael Abd-El-Malek, Eno in traditional systems and their realization in Ursa Minor's storage server, Argon. Argon uses multi Argon to provide to each client a configurable fraction (e.g., 0.9) of its standalone efficiency

  10. Textile wastewater purification through natural coagulants

    NASA Astrophysics Data System (ADS)

    Beltrán-Heredia, J.; Sánchez-Martín, J.; Rodríguez-Sánchez, M. T.

    2011-09-01

    A new coagulant obtained through polymerization of Acacia mearnsii de Wild tannin extract has been characterized in the removal of two dangerous dye pollutants: Alizarin Violet 3R and Palatine Fast Black WAN. This coagulant is lab-synthesized according to the etherification of tannins with glycidyltrimethylammonium chloride and formaldehyde and its performance in dye removal in terms of efficiency was high. Reasonably low coagulant dosages (ca. 50 mg L-1) reaches high capacity levels (around 0.8 for Alizarin Violet 3R and 1.6 for Palatine Fast Black WAN mg dye mg-1 of coagulant) and pH and temperature are not extremely affecting variables. The systems coagulant dyes were successfully modeled by applying the Langmuir hypothesis. q max and b parameters were obtained with an adjusted correlation factor ( r 2) above 0.8.

  11. Oxidation Inhibits Iron-Induced Blood Coagulation

    PubMed Central

    Pretorius, Etheresia; Bester, Janette; Vermeulen, Natasha; Lipinski, Boguslaw

    2013-01-01

    Blood coagulation under physiological conditions is activated by thrombin, which converts soluble plasma fibrinogen (FBG) into an insoluble clot. The structure of the enzymatically-generated clot is very characteristic being composed of thick fibrin fibers susceptible to the fibrinolytic degradation. However, in chronic degenerative diseases, such as atherosclerosis, diabetes mellitus, cancer, and neurological disorders, fibrin clots are very different forming dense matted deposits (DMD) that are not effectively removed and thus create a condition known as thrombosis. We have recently shown that trivalent iron (ferric ions) generates hydroxyl radicals, which subsequently convert FBG into abnormal fibrin clots in the form of DMDs. A characteristic feature of DMDs is their remarkable and permanent resistance to the enzymatic degradation. Therefore, in order to prevent thrombotic incidences in the degenerative diseases it is essential to inhibit the iron-induced generation of hydroxyl radicals. This can be achieved by the pretreatment with a direct free radical scavenger (e.g. salicylate), and as shown in this paper by the treatment with oxidizing agents such as hydrogen peroxide, methylene blue, and sodium selenite. Although the actual mechanism of this phenomenon is not yet known, it is possible that hydroxyl radicals are neutralized by their conversion to the molecular oxygen and water, thus inhibiting the formation of dense matted fibrin deposits in human blood. PMID:23170793

  12. Electrical conductivity of compressed argon

    SciTech Connect

    Bauer, R. [Univ. Regensburg (Germany); Windl, W.; Collins, L.; Kress, J.; Kwon, I. [Los Alamos National Lab., NM (United States)

    1997-10-01

    The authors report calculations of the electrical conductivity of solid argon as a function of compression within the density functional local density approximation formulation for a norm-conserving pseudopotential using both electron-phonon coupling and molecular dynamics techniques.

  13. The Liquid Argon Purity Demonstrator

    NASA Astrophysics Data System (ADS)

    Adamowski, M.; Carls, B.; Dvorak, E.; Hahn, A.; Jaskierny, W.; Johnson, C.; Jostlein, H.; Kendziora, C.; Lockwitz, S.; Pahlka, B.; Plunkett, R.; Pordes, S.; Rebel, B.; Schmitt, R.; Stancari, M.; Tope, T.; Voirin, E.; Yang, T.

    2014-07-01

    The Liquid Argon Purity Demonstrator was an R&D test stand designed to determine if electron drift lifetimes adequate for large neutrino detectors could be achieved without first evacuating the cryostat. We describe here the cryogenic system, its operations, and the apparatus used to determine the contaminant levels in the argon and to measure the electron drift lifetime. The liquid purity obtained by this system was facilitated by a gaseous argon purge. Additionally, gaseous impurities from the ullage were prevented from entering the liquid at the gas-liquid interface by condensing the gas and filtering the resulting liquid before returning to the cryostat. The measured electron drift lifetime in this test was greater than 6 ms, sustained over several periods of many weeks. Measurements of the temperature profile in the argon, to assess convective flow and boiling, were also made and are compared to simulation.

  14. Development of Coagulation Factor Probes for the Identification of Procoagulant Circulating Tumor Cells

    PubMed Central

    Tormoen, Garth W.; Cianchetti, Flor A.; Bock, Paul E.; McCarty, Owen J. T.

    2012-01-01

    Metastatic cancer is associated with a hypercoagulable state, and pathological venous thromboembolic disease is a significant source of morbidity and the second leading cause of death in patients with cancer. Here we aimed to develop a novel labeling strategy to detect and quantify procoagulant circulating tumor cells (CTCs) from patients with metastatic cancer. We hypothesize that the enumeration of procoagulant CTCs may be prognostic for the development of venous thrombosis in patients with cancer. Our approach is based on the observation that cancer cells are capable of initiating and facilitating cell-mediated coagulation in vitro, whereby activated coagulation factor complexes assemble upon cancer cell membrane surfaces. Binding of fluorescently labeled, active site-inhibited coagulation factors VIIa, Xa, and IIa to the metastatic breast cancer cell line, MDA-MB-231, non-metastatic colorectal cell line, SW480, or metastatic colorectal cell line, SW620, was characterized in a purified system, in anticoagulated blood and plasma, and in plasma under conditions of coagulation. We conclude that a CTC labeling strategy that utilizes coagulation factor-based fluorescent probes may provide a functional assessment of the procoagulant potential of CTCs, and that this strategy is amenable to current CTC detection platforms. PMID:22973554

  15. Coagulation factor VA2440G causes east Texas bleeding disorder via TFPI?

    PubMed Central

    Vincent, Lisa M.; Tran, Sinh; Livaja, Ruzica; Bensend, Tracy A.; Milewicz, Dianna M.; Dahlbäck, Björn

    2013-01-01

    The autosomal dominantly inherited east Texas bleeding disorder is linked to an A2440G variant in exon 13 of the F5 gene. Affected individuals have normal levels of coagulation factor V (FV) activity, but demonstrate inhibition of global coagulation tests. We demonstrated that the A2440G mutation causes upregulation of an alternatively spliced F5 transcript that results in an in-frame deletion of 702 amino acids of the large activation fragment, the B domain. The approximately 250-kDa FV isoform (FV-short), which can be fully activated by thrombin, is present in all A2440G carriers’ plasma (n = 16). FV-short inhibits coagulation through an indirect mechanism by forming a complex with tissue factor pathway inhibitor-? (TFPI?), resulting in an approximately 10-fold increase in plasma TFPI?, suggesting that the TFPI?:FV-short complexes are retained in circulation. The TFPI?:FV-short complexes efficiently inhibit thrombin generation of both intrinsic and extrinsic coagulation pathways. These data demonstrate that the east Texas bleeding disorder–associated F5A2440G leads to the formation of the TFPI?:FV-short complex, which inhibits activation and propagation of coagulation. PMID:23979162

  16. Coagulation factor V(A2440G) causes east Texas bleeding disorder via TFPI?.

    PubMed

    Vincent, Lisa M; Tran, Sinh; Livaja, Ruzica; Bensend, Tracy A; Milewicz, Dianna M; Dahlbäck, Björn

    2013-09-01

    The autosomal dominantly inherited east Texas bleeding disorder is linked to an A2440G variant in exon 13 of the F5 gene. Affected individuals have normal levels of coagulation factor V (FV) activity, but demonstrate inhibition of global coagulation tests. We demonstrated that the A2440G mutation causes upregulation of an alternatively spliced F5 transcript that results in an in-frame deletion of 702 amino acids of the large activation fragment, the B domain. The approximately 250-kDa FV isoform (FV-short), which can be fully activated by thrombin, is present in all A2440G carriers' plasma (n = 16). FV-short inhibits coagulation through an indirect mechanism by forming a complex with tissue factor pathway inhibitor-? (TFPI?), resulting in an approximately 10-fold increase in plasma TFPI?, suggesting that the TFPI?:FV-short complexes are retained in circulation. The TFPI?:FV-short complexes efficiently inhibit thrombin generation of both intrinsic and extrinsic coagulation pathways. These data demonstrate that the east Texas bleeding disorder-associated F5(A2440G) leads to the formation of the TFPI?:FV-short complex, which inhibits activation and propagation of coagulation. PMID:23979162

  17. Supplemental Information for Threshold Response of Initiation of Blood Coagulation by Tissue Factor in

    E-print Network

    Ismagilov, Rustem F.

    1 Supplemental Information for Threshold Response of Initiation of Blood Coagulation by Tissue plasma (NPP) was purchased from George King Bio-Medical, Inc. (Overland Park, KS). Human whole blood to remove excess BTS. The silanized capillary was then rinsed with ethanol (2 mL) and dried with nitrogen

  18. Platelet and coagulation factor variations induced in vitro by polyethylene terephthalate (Dacron ®) coated with pyrolytic carbon

    Microsoft Academic Search

    Elisabetta Cenni; Carla Renata Arciola; Gabriela Ciapetti; Donatella Granchi; Lucia Savarino; Susanna Stea; Daniela Cavedagna; Tiziano Curti; Giuseppina Falsone; Arturo Pizzoferrato

    1995-01-01

    The haemocompatibility of polyethylene terephthalate (Dacron®) coated with pyrolytic carbon was examined in vitro, evaluating its capability of inducing adhesion and platelet activation, and of modifying the intrinsic coagulation pathway. Platelet adhesion was evaluated by counting platelets before and after in vitro contact of human plasma with the material under examination. Platelet activation was evaluated by determining platelet factor 4

  19. Comparison of a novel polytitanium chloride coagulant with polyaluminium chloride: coagulation performance and floc characteristics.

    PubMed

    Zhao, Y X; Phuntsho, S; Gao, B Y; Yang, Y Z; Kim, J-H; Shon, H K

    2015-01-01

    Polymerized inorganic coagulants are increasingly being used in the water supply and wastewater treatment process, yet there is limited research on the development of polytitanium coagulants. The aim of this study is to synthesize polytitanium chloride (PTC) coagulants and investigate their coagulation behavior and floc characteristics for humic acid removal in comparison to polyaluminum chloride (PAC). The PTC samples with different B (molar ratios of OH/Ti) values were prepared using an instantaneous base-feeding method, employing sodium carbonate as the basification agent. The coagulation efficiency was significantly influenced by different B values. The results suggest that the humic acid removal increased with the increasing B value for PAC, while the inverse trend was observed for PTC. The optimum B value was chosen at 1.0 and 2.0 for PTC and PAC, respectively. Under the optimum coagulant dose and initial solution pH conditions, the PTC coagulant performed better than the PAC coagulant and the floc properties were significantly improved in terms of floc growth rate and floc size. However, the PAC coagulants produced flocs with better floc recoverability than the PTC coagulants. PMID:25291677

  20. Resection of meningiomas with implantable microwave coagulation

    SciTech Connect

    Zhou, X.P.; Xie, Q.L.; Liu, J.M.; Yue, Z.J.; Cai, K.H. [Second Military Medical Univ., Shanghai (China)] [Second Military Medical Univ., Shanghai (China)

    1996-05-01

    Implantable microwave coagulation was used to perform resection on 62 patients that had intracranial meningiomas. When 20--60 W microwave power was applied for 15 s, the temperature at the center of the tumor tissue was 43--63 C; 30 mm from the center, the temperature was under 40 C. Histological changes in the center of the tumor showed coagulative necrosis, diminished nuclei, and obliterated blood vessels. The changes at 10--20 mm from the center of the tumor showed coagulative necrosis and degeneration and, 30--50 mm from the center of the tumor, showed normal cell morphology after microwave coagulation. The thermal field in brain tumor has an effective diameter of about 40 mm. No side effects on the normal brain tissues were observed. The amount of blood loss during the operation was minimal while the meningioma was coagulated, especially when the meningioma was located at the skull base or in the parasagittal or cerebral convexity region. After microwave coagulation, the entire tumor could easily be removed. Among the 62 surgically treated cases, gross total tumor excision was 85%. No postoperative complications occurred after microwave coagulation, and there was no operative mortality in the series. The authors believe that this new technique has the advantage of simplicity, less blood loss, and smooth postoperative procedures. Hemostatic effects during the operation are satisfactory, and blood transfusion can be reduced by 50--60%.

  1. Transfusion and coagulation management in liver transplantation

    PubMed Central

    Clevenger, Ben; Mallett, Susan V

    2014-01-01

    There is wide variation in the management of coagulation and blood transfusion practice in liver transplantation. The use of blood products intraoperatively is declining and transfusion free transplantations take place ever more frequently. Allogenic blood products have been shown to increase morbidity and mortality. Primary haemostasis, coagulation and fibrinolysis are altered by liver disease. This, combined with intraoperative disturbances of coagulation, increases the risk of bleeding. Meanwhile, the rebalancing of coagulation homeostasis can put patients at risk of hypercoagulability and thrombosis. The application of the principles of patient blood management to transplantation can reduce the risk of transfusion. This includes: preoperative recognition and treatment of anaemia, reduction of perioperative blood loss and the use of restrictive haemoglobin based transfusion triggers. The use of point of care coagulation monitoring using whole blood viscoelastic testing provides a picture of the complete coagulation process by which to guide and direct coagulation management. Pharmacological methods to reduce blood loss include the use of anti-fibrinolytic drugs to reduce fibrinolysis, and rarely, the use of recombinant factor VIIa. Factor concentrates are increasingly used; fibrinogen concentrates to improve clot strength and stability, and prothrombin complex concentrates to improve thrombin generation. Non-pharmacological methods to reduce blood loss include surgical utilisation of the piggyback technique and maintenance of a low central venous pressure. The use of intraoperative cell salvage and normovolaemic haemodilution reduces allogenic blood transfusion. Further research into methods of decreasing blood loss and alternatives to blood transfusion remains necessary to continue to improve outcomes after transplantation. PMID:24876736

  2. The Effect of Ozone on Cold Water Coagulation

    Microsoft Academic Search

    S. Y. Jasim; S. Ndiongue; B. Johnson; L. Schweitzer; D. Borikar

    2008-01-01

    The application of pre-coagulation ozone in drinking water treatment to provide primary disinfection, has an impact on coagulation and flocculation, and needs to be evaluated further for cold water temperatures, especially when accompanied by episodes of high alkalinity and dissolved organic carbon (DOC). Ozone application to raw water, prior to the addition of coagulants and coagulant aides, was shown to

  3. A simple, general approach of allosteric coagulation enzyme inhibition through monosulfated hydrophobic scaffolds.

    PubMed

    Sidhu, Preetpal Singh; Zhou, Qibing; Desai, Umesh R

    2014-12-15

    Allosteric inhibition of coagulation enzymes offers the advantage of controlled inhibition. In this study, a small library of mono sulfated indole and benzothiazole based molecules was synthesized and screened against the panel of coagulation proteases. The results reveal that selected molecules inhibit the thrombin, factor Xa and factor XIa with moderate potency. Compound 6a was found to have an allosteric mode of inhibition against thrombin. Plasma clotting assays suggest that selected inhibitors 14b, 14c and 14d prolong both prothrombin and activated partial thromboplastin time. Overall, this work presents the newer class of allosteric inhibitors of thrombin and factor XIa with improved aqueous solubility profile. PMID:25453807

  4. Antithrombin-III treatment limits disseminated intravascular coagulation in endotoxemia.

    PubMed

    Redens, T B; Emerson, T E

    1989-05-01

    Gram-negative septicemia/endotoxemia remains a serious clinical disorder that is often complicated by disseminated intravascular coagulation (DIC). Plasma antithrombin-III (AT-III) levels usually decrease during gram-negative septicemia/endotoxemia, and even moderate decreases in this major inhibitor of the coagulation system are associated with serious DIC. We demonstrated in an earlier study that prophylactic treatment of rats with 250 U/kg of AT-III followed by endotoxin challenge markedly attenuates DIC, indices of organ damage, and metabolic dysfunction. The present study was to determine whether treatment with 250 U/kg AT-III 1 hr after endotoxin challenge would be similarly efficacious. Rats treated with 250 U/kg of AT-III inactivated by human sputum elastase (ATX) served as protein controls. Blood samples for analysis were obtained 4 hr after AT-III or ATX treatment (5 hr after endotoxin challenge). Rats in the ATX treatment group exhibited abnormalities characteristic of endotoxemia, i.e., decreased fibrinogen levels and platelet counts, increases in prothrombin time and activated partial thromboplastin time, elevated serum glutamic oxaloacetic transaminase (SGOT) and alkaline phosphatase (AKP), and hypoglycemia. Treatment with AT-III markedly and significantly (P less than .05) attenuated all of these abnormalities, although survival was not increased. This study strongly suggests that supplementation of plasma AT-III is efficacious after the development of sepsis, although not as efficacious as prophylactic treatment. PMID:2731321

  5. Inhibiting the intrinsic pathway of coagulation with a FXII-targeting RNA Aptamer

    PubMed Central

    Woodruff, R. S.; Xu, Y.; Layzer, J.; Wu, W.; Ogletreee, M.L.; Sullenger, B.A.

    2013-01-01

    Background Exposure of the plasma protein factor XII to an anionic surface generates activated factor XII that not only triggers the intrinsic pathway of blood coagulation through the activatio of factor XI, but also mediates various vascular responses through activation of the plasma contact system. While deficiencies of factor XII are not associated with excessive bleeding, thrombosis models in factor deficient animals have suggested that this protein contributes to stable thrombus formation. Therefore, factor XII has emerged as an attractive therapeutic target to treat or prevent pathological thrombosis formation without increasing the risk for hemorrhage. Objectives Utilizing an in vitro directed evolution and chemical biology approach, we sought to isolate a nuclease resistant RNA aptamer that binds specifically to factor XII and directly inhibits factor XII coagulant function. Methods and Results Herein, we describe the isolation and characterization of a high affinity RNA aptamer targeting factor XII/XIIa that dose dependently prolongs fibrin clot formation and thrombin generation in clinical coagulation assays. This aptamer functions as a potent anticoagulant by inhibiting the autoactivation of factor XII, as well as inhibiting intrinsic pathway activation (factor XI activation). However, the aptamer does not affect the factor XIIa-mediated activation of the proinflammatory kallikrein-kinin system (plasma kallikrein activation). Conclusions We have generated a specific and potent factor XII/XIIa aptamer anticoagulant that offers targeted inhibition of discrete macromolecular interactions involved in the activation of the intrinsic pathway of blood coagulation. PMID:23692437

  6. Experimental investigations of plasma perturbation in Thomson scattering applied to thermal plasma diagnostics

    E-print Network

    Experimental investigations of plasma perturbation in Thomson scattering applied to thermal plasma ns laser pulses were performed on argon thermal discharge plasma with electron temperature Te 10 000 discharge plasmas 1­5 , laser-induced plasmas 6­9 , pinch plasmas 10­12 , but also to study thermal plasmas

  7. 21 CFR 864.5400 - Coagulation instrument.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology Devices § 864.5400 Coagulation instrument. (a)...

  8. 21 CFR 864.5400 - Coagulation instrument.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology Devices § 864.5400 Coagulation instrument. (a)...

  9. Coagulation testing in the perioperative period

    PubMed Central

    Thiruvenkatarajan, Venkatesan; Pruett, Ashlee; Adhikary, Sanjib Das

    2014-01-01

    Perioperative coagulation management is a complex task that has a significant impact on the perioperative journey of patients. Anaesthesia providers play a critical role in the decision-making on transfusion and/or haemostatic therapy in the surgical setting. Various tests are available in identifying coagulation abnormalities in the perioperative period. While the rapidly available bedside haemoglobin measurements can guide the transfusion of red blood cells, blood product administration is guided by many in vivo and in vitro tests. The introduction of newer anticoagulant medications and the implementation of the modified in vivo coagulation cascade have given a new dimension to the field of perioperative transfusion medicine. A proper understanding of the application and interpretation of the coagulation tests is vital for a good perioperative outcome. PMID:25535418

  10. ARSENIC REMOVAL BY SOFTENING AND COAGULATION

    EPA Science Inventory

    Drinking water regulations for arsenic (As) and disinfection by-product precursor materials (measured as TOC) are becoming increasingly stringent. Among the modifications to conventional treatment that can improve removal of As and TOC, precipitative softening and coagulation are...

  11. Coagulation of Oil in Water Using Sawdust and Bentonite and the Formation of a Floating Coagulated Material

    E-print Network

    Chung, Deborah D.L.

    is relevant to oil-spill cleanups, water treatment, and water resource management. The coagulation of oil-7870.0000725. © 2013 American Society of Civil Engineers. CE Database subject headings: Coagulation; Oil spills; WaterCoagulation of Oil in Water Using Sawdust and Bentonite and the Formation of a Floating Coagulated

  12. JOURNAL DE PHYSIQUE CoZZoque C7, suppZ6rnent au n07, Tome 40, JuiZZet 1979, page C7-47 INFLUENCE OF PERTURBATIONON POPULATIONPROCESSESOF 4p ARGON LEVELS

    E-print Network

    Boyer, Edmond

    OF PERTURBATIONON POPULATIONPROCESSESOF 4p ARGON LEVELS S. DjeniYe and J.M. Labat. Department of Physics and Meteorology and Institute of Physics, 11000 Beograd, YugosZavia. Population of argon 4p levels in a decaying plasma was found to be predominan- tly due to the dissociative recombination of molecular argon ions

  13. Gas heating in low-pressure microwave argon discharges

    Microsoft Academic Search

    A. Palmero; J. Cotrino; C. Lao; A. R. González-Elipe

    2002-01-01

    Both an energy balance equation and a collisional-radiative model were developed in order to discover which process is responsible for gas heating in a low-pressure argon discharge. In this way, for a wide range of plasma conditions, the space-charge field contribution to gas heating was found to be negligible compared to that resulting from elastic collisional processes, although the value

  14. Dust Coagulation in Protoplanetary Accretion Disks

    NASA Technical Reports Server (NTRS)

    Schmitt, W.; Henning, Th.; Mucha, R.

    1996-01-01

    The time evolution of dust particles in circumstellar disk-like structures around protostars and young stellar objects is discussed. In particular, we consider the coagulation of grains due to collisional aggregation. The coagulation of the particles is calculated by solving numerically the non-linear Smoluchowski equation. The different physical processes leading to relative velocities between the grains are investigated. The relative velocities may be induced by Brownian motion, turbulence and drift motion. Starting from different regimes which can be identified during the grain growth we also discuss the evolution of dust opacities. These opacities are important for both the derivation of the circumstellar dust mass from submillimeter/millimeter continuum observations and the dynamical behavior of the disks. We present results of our numerical studies of the coagulation of dust grains in a turbulent protoplanetary accretion disk described by a time-dependent one-dimensional (radial) alpha-model. For several periods and disk radii, mass distributions of coagulated grains have been calculated. From these mass spectra, we determined the corresponding Rosseland mean dust opacities. The influence of grain opacity changes due to dust coagulation on the dynamical evolution of a protostellar disk is considered. Significant changes in the thermal structure of the protoplanetary nebula are observed. A 'gap' in the accretion disk forms at the very frontier of the coagulation, i.e., behind the sublimation boundary in the region between 1 and 5 AU.

  15. On Coagulation and the Stellar Mass Spectrum

    NASA Astrophysics Data System (ADS)

    Allen, Eric J.; Bastien, Pierre

    1995-10-01

    The importance of coagulation in the making of the stellar mass spectrum is studied using two coagulation indicators and the model of Lejeune and Bastien. A search is made for correlations between these indicators and the physical characteristics of the four types of stellar groups investigated here: open clusters (54 cases), OB associations (16 cases), globular clusters (16 cases), and galaxies (13 cases). Although (1) coagulation is certainly not the only physical process which determines eventually the stellar mass spectrum and (2) the Lejeune and Bastien analytical solution describes only approximately the physics involved, we found that it fits the mass spectra extremely well. The fits are definitely much better than the usual power-law fits. The results show that coagulation seems to be pretty independent of the conditions at which it takes place. The means of the coagulation indicators for each type of stellar group are found to be quite close to each other (within the limits of uncertainty), which adds more weight to these results. It is also found that the effects of coagulation are difficult to show, at least for stellar groups with ages greater than econg 107 yr. A method of assessing the amount of mass loss by the cluster is also described.

  16. Removal of silver nanoparticles by coagulation processes.

    PubMed

    Sun, Qian; Li, Yan; Tang, Ting; Yuan, Zhihua; Yu, Chang-Ping

    2013-10-15

    Commercial use of silver nanoparticles (AgNPs) will lead to a potential route for human exposure via potable water. Coagulation followed by sedimentation, as a conventional technique in the drinking water treatment facilities, may become an important barrier to prevent human from AgNP exposures. This study investigated the removal of AgNP suspensions by four regular coagulants. In the aluminum sulfate and ferric chloride coagulation systems, the water parameters slightly affected the AgNP removal. However, in the poly aluminum chloride and polyferric sulfate coagulation systems, the optimal removal efficiencies were achieved at pH 7.5, while higher or lower of pH could reduce the AgNP removal. Besides, the increasing natural organic matter (NOM) would reduce the AgNP removal, while Ca(2+) and suspended solids concentrations would also affect the AgNP removal. In addition, results from the transmission electron microscopy and X-ray diffraction showed AgNPs or silver-containing nanoparticles were adsorbed onto the flocs. Finally, natural water samples were used to validate AgNP removal by coagulation. This study suggests that in the case of release of AgNPs into the source water, the traditional water treatment process, coagulation/sedimentation, can remove AgNPs and minimize the silver ion concentration under the well-optimized conditions. PMID:23973474

  17. Bright hydrogen-light source due to a resonant energy transfer with strontium and argon ions

    Microsoft Academic Search

    Randell L Mills; Mark Nansteel; Paresh C Ray

    2002-01-01

    A plasma called a resonant transfer (rt) plasma formed with a low field (1 V cm-1), at low temperatures (e.g. ?103 K), from atomic hydrogen generated at a tungsten filament and strontium which was vapourized by heating the metal. Strong vacuum ultraviolet emission was observed that increased with the addition of argon, but not when sodium, magnesium or barium replaced

  18. Bright hydrogen-light source due to a resonant energy transfer with strontium and argon ions

    Microsoft Academic Search

    Randell L. Mills; Mark Nansteel; Paresh C. Ray

    2002-01-01

    A plasma called a resonant transfer (rt) plasma formed with a low field (1 V cm-1), at low temperatures (e.g. ≈103 K), from atomic hydrogen generated at a tungsten filament and strontium which was vapourized by heating the metal. Strong vacuum ultraviolet emission was observed that increased with the addition of argon, but not when sodium, magnesium or barium replaced

  19. Evidence for factor IX-independent roles for factor XIa in blood coagulation

    PubMed Central

    Matafonov, Anton; Cheng, Qiufang; Geng, Yipeng; Verhamme, Ingrid M.; Umunakwe, Obi; Tucker, Erik I.; Sun, Mao-fu; Serebrov, Vladimir; Gruber, Andras; Gailani, David

    2014-01-01

    Background Factor (f) XIa is traditionally assigned a role in fIX activation during coagulation. However, recent evidence suggests this protease may have additional plasma substrates. Objective To determine if fXIa promotes thrombin generation and coagulation in plasma in the absence of fIX, and to determine if fXI deficiency produces an antithrombotic effect in mice independent of fIX. Methods FXIa, fXIa variants, and anti-fXIa antibodies were tested for their effects on plasma coagulation and thrombin generation in the absence of fIX, and for their effects on activation of purified coagulation factors. Mice with combined fIX and fXI deficiency were compared to mice lacking either fIX or fXI in an arterial thrombosis model. Results In fIX-deficient plasma, fXIa induced thrombin generation and anti-fXIa antibodies prolonged clotting times. This process involved fXIa-mediated conversion of fX and fV to their active forms. Activation of fV by fXIa required the A3 domain on the fXIa heavy chain, while activation of fX did not. FX activation by fXIa, unlike fIX activation, was not a calcium-dependent process. Mice lacking both fIX and fXI were more resistance to ferric chloride-induced carotid artery occlusion than fXI-deficient or fIX-deficient mice. Conclusion In addition to its predominant role as an activator of fIX, fXIa may contribute to coagulation by activating fX and fV. As the latter reactions do not require calcium, they may make important contributions to in vitro clotting assays triggered by contact activation. The reactions may be relevant to fXIa's roles in hemostasis and in promoting thrombosis. PMID:24152424

  20. Sonoluminescing Air Bubbles Rectify Argon

    SciTech Connect

    Lohse, D.; Hilgenfeldt, S. [Fachbereich Physik der Universitaet Marburg, Renthof 6, 35032 Marburg (Germany)] [Fachbereich Physik der Universitaet Marburg, Renthof 6, 35032 Marburg (Germany); Brenner, M.P. [Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Dupont, T.F. [Department of Computer Science, University of Chicago, Chicago, Illinois 60637 (United States)] [Department of Computer Science, University of Chicago, Chicago, Illinois 60637 (United States); Johnston, B. [Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States)] [Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States)

    1997-02-01

    The dynamics of single bubble sonoluminescence (SBSL) strongly depends on the percentage of inert gas within the bubble. We propose a theory for this dependence, based on a combination of principles from sonochemistry and hydrodynamic stability. The nitrogen and oxygen dissociation and subsequent reaction to water soluble gases implies that strongly forced air bubbles eventually consist of pure argon. Thus it is the partial argon (or any other inert gas) pressure which is relevant for stability. The theory provides quantitative explanations for many aspects of SBSL. {copyright} {ital 1997} {ital The American Physical Society}

  1. Coagulation algorithms with size binning

    NASA Technical Reports Server (NTRS)

    Statton, David M.; Gans, Jason; Williams, Eric

    1994-01-01

    The Smoluchowski equation describes the time evolution of an aerosol particle size distribution due to aggregation or coagulation. Any algorithm for computerized solution of this equation requires a scheme for describing the continuum of aerosol particle sizes as a discrete set. One standard form of the Smoluchowski equation accomplishes this by restricting the particle sizes to integer multiples of a basic unit particle size (the monomer size). This can be inefficient when particle concentrations over a large range of particle sizes must be calculated. Two algorithms employing a geometric size binning convention are examined: the first assumes that the aerosol particle concentration as a function of size can be considered constant within each size bin; the second approximates the concentration as a linear function of particle size within each size bin. The output of each algorithm is compared to an analytical solution in a special case of the Smoluchowski equation for which an exact solution is known . The range of parameters more appropriate for each algorithm is examined.

  2. Controlling difficult pelvic bleeding with argon beam coagulator during laparoscopic ultra low anterior resection.

    PubMed

    Kandeel, Ahmed; Meguid, Ahmed; Hawasli, Abdelkader

    2011-02-01

    In recent years, the standard of care for lower rectal tumors has developed to include a total mesorectal excision, which provides optimal long-term results. There has been debate with regard to the best approach for lower rectal tumors, conventional open versus less invasive procedures. As the trend toward less invasive surgical procedures progresses, similar complications, which are seen in open cases, are being encountered, such as the notorious presacral fascia bleed. These are small vessels, which are difficult to locate and control. Surgical literature suggests different methods during laparoscopic procedures. These include: placing lap pads and holding pressure, placing saline bag, placing tacks, using bone wax, and electrocautry at different settings. We present a case of a 57-year-old male, positive for lymph node disease, who underwent laparoscopic ultra low anterior resection with total mesorectal excision and protective loop ileostomy. PMID:21304367

  3. Argon SDC detector cryogenic design

    SciTech Connect

    Slack, D.S.

    1991-10-25

    A first cut at designing the cryogenic systems is resented. The point design or sample design presented includes flow-rate calculations, piping sizes, dewar elevations, etc. In summary, the analysis shows argon cooling is ample even with relatively small piping, headers, dewar elevations, etc. This will afford the designer considerable latitude to change the design as required to meet other system requirements. For example, dewar elevation above the detector and horizontal distance to the detector could be varied to meet hall-space requirements. The point design shows a simple system with only one argon supply-and-return pipe to the detector. No nitrogen cooling is required at the detector. No seals or piping (except for an open supply and return header) are required in the detector and a minimum, of baffling to director argon flow is required. No thermal insulation is required to protect modules from pre-amp heat. A simple temperature control technique for the argon loop using a single nitrogen dewar and heat exchanger is shown.

  4. Sonoluminescing Air Bubbles Rectify Argon

    Microsoft Academic Search

    Detlef Lohse; Michael P. Brenner; Todd F. Dupont; Sascha Hilgenfeldt; Blaine Johnston

    1997-01-01

    The dynamics of single bubble sonoluminescence (SBSL) strongly depends on the percentage of inert gas within the bubble. We propose a theory for this dependence, based on a combination of principles from sonochemistry and hydrodynamic stability. The nitrogen and oxygen dissociation and subsequent reaction to water soluble gases implies that strongly forced air bubbles eventually consist of pure argon. Thus

  5. Undriven periodic plasma oscillation in electron cyclotron resonance Ar plasma

    Microsoft Academic Search

    Pyung-Woo Lee; Sang-Won Lee; Hong-Young Chang

    1996-01-01

    We report experimental observation of periodic oscillation in a steady state electron cyclotron resonance argon plasma that is not driven by extra periodic forces. We interpret the oscillation according to the predator-prey model, which is a nonlinear plasma-neutral coupling in the plasma production region. The oscillation is observed in a narrow plasma parameter window and is evidence for neutral density

  6. Helical Organization of Blood Coagulation Factor VIII on Lipid Nanotubes

    PubMed Central

    Miller, Jaimy; Dalm, Daniela; Koyfman, Alexey Y.; Grushin, Kirill; Stoilova-McPhie, Svetla

    2014-01-01

    Cryo-electron microscopy (Cryo-EM)1 is a powerful approach to investigate the functional structure of proteins and complexes in a hydrated state and membrane environment2. Coagulation Factor VIII (FVIII)3 is a multi-domain blood plasma glycoprotein. Defect or deficiency of FVIII is the cause for Hemophilia type A - a severe bleeding disorder. Upon proteolytic activation, FVIII binds to the serine protease Factor IXa on the negatively charged platelet membrane, which is critical for normal blood clotting4. Despite the pivotal role FVIII plays in coagulation, structural information for its membrane-bound state is incomplete5. Recombinant FVIII concentrate is the most effective drug against Hemophilia type A and commercially available FVIII can be expressed as human or porcine, both forming functional complexes with human Factor IXa6,7. In this study we present a combination of Cryo-electron microscopy (Cryo-EM), lipid nanotechnology and structure analysis applied to resolve the membrane-bound structure of two highly homologous FVIII forms: human and porcine. The methodology developed in our laboratory to helically organize the two functional recombinant FVIII forms on negatively charged lipid nanotubes (LNT) is described. The representative results demonstrate that our approach is sufficiently sensitive to define the differences in the helical organization between the two highly homologous in sequence (86% sequence identity) proteins. Detailed protocols for the helical organization, Cryo-EM and electron tomography (ET) data acquisition are given. The two-dimensional (2D) and three-dimensional (3D) structure analysis applied to obtain the 3D reconstructions of human and porcine FVIII-LNT is discussed. The presented human and porcine FVIII-LNT structures show the potential of the proposed methodology to calculate the functional, membrane-bound organization of blood coagulation Factor VIII at high resolution. PMID:24961276

  7. Magnetic particle imaging of blood coagulation

    NASA Astrophysics Data System (ADS)

    Murase, Kenya; Song, Ruixiao; Hiratsuka, Samu

    2014-06-01

    We investigated the feasibility of visualizing blood coagulation using a system for magnetic particle imaging (MPI). A magnetic field-free line is generated using two opposing neodymium magnets and transverse images are reconstructed from the third-harmonic signals received by a gradiometer coil, using the maximum likelihood-expectation maximization algorithm. Our MPI system was used to image the blood coagulation induced by adding CaCl2 to whole sheep blood mixed with magnetic nanoparticles (MNPs). The "MPI value" was defined as the pixel value of the transverse image reconstructed from the third-harmonic signals. MPI values were significantly smaller for coagulated blood samples than those without coagulation. We confirmed the rationale of these results by calculating the third-harmonic signals for the measured viscosities of samples, with an assumption that the magnetization and particle size distribution of MNPs obey the Langevin equation and log-normal distribution, respectively. We concluded that MPI can be useful for visualizing blood coagulation.

  8. Magnetic particle imaging of blood coagulation

    SciTech Connect

    Murase, Kenya, E-mail: murase@sahs.med.osaka-u.ac.jp; Song, Ruixiao; Hiratsuka, Samu [Department of Medical Physics and Engineering, Division of Medical Technology and Science, Faculty of Health Science, Graduate School of Medicine, Osaka University, Osaka 565-0871 (Japan)

    2014-06-23

    We investigated the feasibility of visualizing blood coagulation using a system for magnetic particle imaging (MPI). A magnetic field-free line is generated using two opposing neodymium magnets and transverse images are reconstructed from the third-harmonic signals received by a gradiometer coil, using the maximum likelihood-expectation maximization algorithm. Our MPI system was used to image the blood coagulation induced by adding CaCl{sub 2} to whole sheep blood mixed with magnetic nanoparticles (MNPs). The “MPI value” was defined as the pixel value of the transverse image reconstructed from the third-harmonic signals. MPI values were significantly smaller for coagulated blood samples than those without coagulation. We confirmed the rationale of these results by calculating the third-harmonic signals for the measured viscosities of samples, with an assumption that the magnetization and particle size distribution of MNPs obey the Langevin equation and log-normal distribution, respectively. We concluded that MPI can be useful for visualizing blood coagulation.

  9. Microwave diagnostics of atmospheric plasmas

    NASA Astrophysics Data System (ADS)

    Scott, David

    Plasma treatment of biological tissues has tremendous potential due to the wide range of applications. Most plasmas have gas temperatures which greatly exceed room temperature. These are often utilized in electro-surgery for cutting and coagulating tissue. Another type of plasma, referred to as cold atmospheric plasma, or CAP, is characterized by heavy particle temperatures which are at or near room temperature. Due to this lack of thermal effect, CAP may provide less invasive medical procedures. Additionally, CAP have been demonstrated to be effective at targeting cancer cells while minimizing damage to the surrounding tissue. A recently fabricated Microwave Electron Density Device (MEDD) utilizes microwave scattering on small atmospheric plasmas to determine the electron plasma density. The MEDD can be utilized on plasmas which range from a fraction of a millimeter to several centimeters at atmospheric pressure when traditional methods cannot be applied. Microwave interferometry fails due to the small size of the plasma relative to the microwave wavelength which leads to diffraction and negligible phase change; electrostatic probes introduce very strong perturbation and are associated with difficulties of application in strongly-collisional atmospheric conditions; and laser Thomson scattering is not sensitive enough to measure plasma densities less than 1012 cm-3. The first part of this dissertation provides an overview of two types of small atmospheric plasma objects namely CAPs and plasmas utilized in the electro-surgery. It then goes on to describe the fabrication, testing and calibration of the MEDD facility. The second part of this dissertation is focused on the application of the MEDD and other diagnostic techniques to both plasma objects. A series of plasma images that illustrate the temporal evolution of a discharge created by an argon electrosurgical device operating in the coagulation mode and its behavior was analyzed. The discharge of the argon electrosurgical system was studied using an Intensified Charge-Coupled Device (ICCD) and the MEDD. The plasma density was measured and found to be in the range of (7.5-9.5) x 1015 cm-3 for applied powers of 15-60 Watts. The discharge can be classified as a glow discharge of alternating current with a contracted positive column. The discharge ignites every half-wave of the driving voltage when voltage increases above the breakdown threshold of about 300 Volts and is interrupted at the end of each half-wave when the voltage approaches zero. Additionally, it was shown that the plasma discharges on the target object during the positive half-wave of the voltage. The power distribution was also analyzed. It was found that 60-70% of the input power is delivered into the tissue and the remaining 30-40% is consumed by the plasma column between the electrosurgical probe and tissue. The application of the MEDD to a helium CAP revealed the temporal dynamics of the discharge. It was observed that streamer development associated with the measured plasma density peak is developing on the decaying part of the main inter-electrode discharge. The third part of the dissertation focuses on the simulation of a helium CAP. A one-dimensional model of a helium CAP was used to simulate twenty-one oxygen, helium, and nitrogen species. One hundred and forty reactions were successfully used. The predicted maximum and average densities of the species were tabulated. Graphs of the species densities were presented showing the change in densities with respect to the radius of the CAP. The plasma bullets can be seen via these graphs, with most species displaying maximum densities at a radius which is not the center of the CAP. This shows that the plasma bullets are a disk-like structure at the moment of time presented. Values of E/p were varied from 20 -- 30 volts/cm Torr. Based on experimental results of moments in time with which the maximum plasma density occurs, this data can be used to predict the actual E/p values for future experiments.

  10. Advances in the treatment of inherited coagulation disorders.

    PubMed

    Escobar, M A

    2013-09-01

    Inherited coagulation disorders constitute a broad spectrum of coagulation factor deficiencies that include X-linked factor (F)VIII or FIX deficiency that causes haemophilia, and autosomal recessive disorders producing heterogeneous deficiencies in fibrinogen (FI), prothrombin (FII), FV, FVII, FX, FXI, FXIII and combined FV+FVIII. Significant advances in treatments for patients with congenital haemophilia A (FVIII deficiency) and B (FIX deficiency) over the last two decades have resulted from improvements in the production, availability and patient access to factor replacement products. Translation of advances in biotechnology, namely recombinant protein technology, targeted protein modifications to improve function and potentially reduce immunogenicity, and advanced formulations to optimize bioavailability and sustain activity offer promisingly new treatments for haemophilia as well as recessively inherited bleeding disorders in patients who otherwise have few therapeutic options. Though a theoretical risk remains for blood-borne viral infections with pooled plasma-derived products, this concern has diminished with breakthroughs in purification and viral inactivation methods. Development of inhibitory antibodies is still the most daunting problem for patients with inherited bleeding disorders, complicating treatment approaches to control and prevent bleeding, and posing risks for allergic and anaphylactic reactions in susceptible patients. The objectives of this review are to (i) highlight emerging advances in hemostatic therapies that are bioengineered to improve pharmacokinetic properties and bioavailability, sustain functional activity, and possibly eliminate immunogenicity of recombinant factor proteins; and (ii) present an overview of key clinical trials of novel factor products currently in the development pipeline. PMID:23600951

  11. Coagulation and fragmentation dynamics of inertial particles

    E-print Network

    Jens C. Zahnow; Rafael D. Vilela; Ulrike Feudel; Tamás Tél

    2009-08-20

    Inertial particles suspended in many natural and industrial flows undergo coagulation upon collisions and fragmentation if their size becomes too large or if they experience large shear. Here we study this coagulation-fragmentation process in time-periodic incompressible flows. We find that this process approaches an asymptotic, dynamical steady state where the average number of particles of each size is roughly constant. We compare the steady-state size distributions corresponding to two fragmentation mechanisms and for different flows and find that the steady state is mostly independent of the coagulation process. While collision rates determine the transient behavior, fragmentation determines the steady state. For example, for fragmentation due to shear, flows that have very different local particle concentrations can result in similar particle size distributions if the temporal or spatial variation of shear forces is similar.

  12. Fibrinolysis and the control of blood coagulation

    PubMed Central

    Chapin, John C.; Hajjar, Katherine A.

    2014-01-01

    Fibrin plays an essential role in hemostasis as both the primary product of the coagulation cascade and the ultimate substrate for fibrinolysis. Fibrinolysis efficiency is greatly influenced by clot structure, fibrinogen isoforms and polymorphisms, the rate of thrombin generation, the reactivity of thrombus-associated cells such as platelets, and the overall biochemical environment. Regulation of the fibrinolytic system, like that of the coagulation cascade, is accomplished by a wide array of cofactors, receptors, and inhibitors. Fibrinolytic activity can be generated either on the surface of a fibrin-containing thrombus, or on cells that express profibrinolytic receptors. In a widening spectrum of clinical disorders, acquired and congenital defects in fibrinolysis contribute to disease morbidity, and new assays of global fibrinolysis now have potential predictive value in multiple clinical settings. Here, we summarize the basic elements of the fibrinolytic system, points of interaction with the coagulation pathway, and some recent clinical advances. PMID:25294122

  13. Particle-induced oscillations in inductively coupled plasmas

    Microsoft Academic Search

    Achim von Keudell; Martin Bauer

    2004-01-01

    The feedback between particles and the heating of an inductively coupled plasma (ICP) from argon is investigated. The ICP is heated by a pancake coil antenna, which is coupled to the plasma via a dielectric window. Particles are generated by injecting a pulse of acetylene for a few seconds into an argon plasma. Afterwards, the emission of the ICP starts

  14. [Relationship among coagulation effect of Al-based coagulant, content and speciation of residual aluminum].

    PubMed

    Yang, Zhong-Lian; Gao, Bao-Yu; Yue, Qin-Yan; Jiang, Yi-Shuai

    2010-06-01

    The application of AlCl3, Al2 (SO4)3 and poly-aluminum chloride (PAC) in humic acid-kaolin simulated water was studied in this article. It is intended to discuss the relationship among coagulation effect of Al-based coagulants in humic acid-kaolin simulated water and content and speciation of residual aluminum. It was found that, the turbidity removal efficiency and UV254 removal efficiency could reach about 90% at the tested dosage. At higher dosage, PAC gave better coagulation effect. The residual total aluminum content and residual aluminum ratio of PAC, which was 0.9 mg/L and - 3.0% or so respectively, were greatly lower than those of AlCl3 and Al2 (SO4)3. The residual total dissolved aluminum was the predominant content in the effluent after coagulation and sedimentation by the three Al-based coagulants. For the total dissolved aluminum, the proportion of dissolved organic aluminum was significantly higher than that of other aluminum speciation. With respect to humic acid-kaolin simulated water, the content of residual total aluminum in the effluent after coagulation and sedimentation by PAC decreased obviously compared to AlCl3 and Al2 (SO4)3. PAC could effectively decrease the content of residual dissolved aluminum speciation which has higher toxicity. The content of residual total dissolved aluminum in the effluent after coagulation and sedimentation by PAC was about 0.6 mg/L. PMID:20698270

  15. Effect of Argon Addition on Morphology and Structure of Diamond Films (from Microcrystalline to Nanocrystalline)

    NASA Astrophysics Data System (ADS)

    LV, Lin; WANG, Jianhua; WENG, Jun; CUI, Xiaohui; ZHANG, Ying

    2015-03-01

    Micro-/nanocrystalline diamond films deposited in Ar/H2/CH4 microwave plasmas have been studied, with argon flow rates in the range of 70-100 sccm. The effects of argon addition on morphology, surface roughness, quality and structure were investigated by scanning electron microscopy, surface profiler, Raman spectrometer and X-ray diffraction (XRD). It is demonstrated that when the argon flow rate is 70 sccm or 75 sccm, well-faceted polycrystalline diamond films can be grown at a low substrate temperature less than 610 °C. With the increase in the argon flow rate, the smooth crystallographic planes disappear gradually. Instead, rough crystallographic planes made up of small aggregates begin to take shape, resulting from the increase in the secondary nucleation rate. Nanocrystalline diamond films were obtained at a flow rate of 100 sccm, and all of the prepared diamond films were smooth, with a surface roughness (Ra) less than 20 nm. Raman analyses reveal that the amount of amorphous carbon increases significantly with the increase in argon flow. The results of XRD show that crystalline size and preferential orientation of diamond films depend on the argon content in the plasmas. supported by National Natural Science Foundation of China (No. 11175137)

  16. Determination of the rate coefficient of the electron-impact excitation from the argon resonance states (1s2 and 1s4) to 2p states by the emission line ratio in an afterglow plasma

    NASA Astrophysics Data System (ADS)

    Cheng, Zhi-Wen; Zhu, Xi-Ming; Liu, Fei-Xiang; Pu, Yi-Kang

    2015-04-01

    The rate coefficients of electron-impact excitation from argon 1s2 and 1s4 (resonance states) to 2p states are determined in the electron temperature (Te) range of 0.5–1.1 eV. This is achieved by using a population model for Ar(2p) and measured parameters in the afterglow of an rf (60 MHz) pulsed capacitive discharge. These parameters include the densities of the 2p states (optical emission spectroscopy), the densities of the four argon 1s states (diode laser absorption), and Te (a Langmuir probe and a line-ratio technique), for discharges with two gas mixtures: Ar(60 mTorr)/O2(2 mTorr) and Ar(60 mTorr)/Xe(1.8 mTorr). It is found that the rate coefficients obtained in this work agree well with those from the cross sections by a large-scale R-matrix calculation reported recently by Zatsarinny et al (2004 J. Phys. B: At. Mol. Opt. Phys. 37 4693, 2014 Phys. Rev. A 89 022706).

  17. Boltzmann expansion in a radiofrequency conical helicon thruster operating in xenon and argon

    SciTech Connect

    Charles, C.; Boswell, R. [Space Plasma, Power and Propulsion Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)] [Space Plasma, Power and Propulsion Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Takahashi, K. [Space Plasma, Power and Propulsion Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia) [Space Plasma, Power and Propulsion Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Department of Electrical Engineering, Tohoku University, Sendai 980-9579 (Japan)

    2013-06-03

    A low pressure ({approx}0.5 mTorr in xenon and {approx}1 mTorr in argon) Boltzmann expansion is experimentally observed on axis within a magnetized (60 to 180 G) radiofrequency (13.56 MHz) conical helicon thruster for input powers up to 900 W using plasma parameters measured with a Langmuir probe. The axial forces, respectively, resulting from the electron and magnetic field pressures are directly measured using a thrust balance for constant maximum plasma pressure and show a higher fuel efficiency for argon compared to xenon.

  18. Computer-assisted interstitial laser coagulation for BPH

    NASA Astrophysics Data System (ADS)

    Ho, Gideon; Barrett, Adrian R. W.; Ng, Wan S.; Lim, Liam G.; Cheng, Wai S.

    2001-06-01

    Interstitial laser thermotherapy is a minimally invasive surgical procedure that utilizes laser to coagulate and treat benign prostatic hyperplasia. This study explores the use of a computer-assisted interstitial laser coagulation system to aid surgeons in performing this procedure.

  19. Assessing blood coagulation status with laser speckle rheology

    PubMed Central

    Tripathi, Markandey M.; Hajjarian, Zeinab; Van Cott, Elizabeth M.; Nadkarni, Seemantini K.

    2014-01-01

    We have developed and investigated a novel optical approach, Laser Speckle Rheology (LSR), to evaluate a patient’s coagulation status by measuring the viscoelastic properties of blood during coagulation. In LSR, a blood sample is illuminated with laser light and temporal speckle intensity fluctuations are measured using a high-speed CMOS camera. During blood coagulation, changes in the viscoelastic properties of the clot restrict Brownian displacements of light scattering centers within the sample, altering the rate of speckle intensity fluctuations. As a result, blood coagulation status can be measured by relating the time scale of speckle intensity fluctuations with clinically relevant coagulation metrics including clotting time and fibrinogen content. Our results report a close correlation between coagulation metrics measured using LSR and conventional coagulation results of activated partial thromboplastin time, prothrombin time and functional fibrinogen levels, creating the unique opportunity to evaluate a patient’s coagulation status in real-time at the point of care. PMID:24688816

  20. Safety procedures of coagulation factors.

    PubMed

    Jorquera, J I

    2007-12-01

    Two main types of safety procedures must be applied to biological products, including plasma derivatives: (i) preventive procedures and (ii) elimination procedures. Prevention includes epidemiological control of donor populations; checks on each donor's health condition; analysis of each donation for the main pathogens using serological methods; additional analysis of all plasma for human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis A virus (HAV) and the B19 virus, using nucleic acid amplification techniques (NAT). A 60 days or longer inventory hold of all plasma donations is applied, to allow additional time to discard previous donations from potential seroconverting or otherwise rejectable donors. Elimination procedures minimize the low residual risk of transmitting pathogens, including unknown or previously undetected ones. Since the introduction 20 years ago of solvent-detergent treatment, very effective against enveloped viruses (HIV, HBV, HCV, West Nile virus, SARS, avian influenza virus etc), there have been no known cases of transmission of this type of pathogens by products manufactured according to this procedure. Other inactivation procedures such as pasteurization, dry-heat or nanofiltration may prove equally effective. In addition, dry-heat treatment and nanofiltration are capable of effectively eliminating non-enveloped viruses (HAV, B19 virus). Recent studies show that the B19 virus is much more sensitive to heat (in lyophilized state or by pasteurization) and acid pH than previously thought. Although there is no evidence for the transmission of classic transmissible spongiform encephalopathies (TSEs) through blood or blood-products transfusion, four possible cases have been reported in the United Kingdom involving transmission by non-leukoreduced blood components of the agent that causes variant Creutzfeldt-Jakob Disease (vCJD), a disease linked to the outbreak of bovine spongiform encephalopathy (BSE) which took place in that country. However, there are no cases of human TSE (classic or variant) transmission by plasma-derived products. Analytical methods capable of detecting the vCJD agent in patients' brains (where high titres are found) and other tissues (such as the spleen, appendix and lymph nodes, where much lower concentrations are found) are unable to detect the agent in blood or plasma from patients with vCJD, even in the clinical phase of the disease. Experiments by Grifols and other groups show that the capacity of the production processes to eliminate vCJD agent models is many orders of magnitude greater than the maximum expected load of the agent. In this regard, the efficacy of precipitation, affinity chromatography, depth filtration and nanofiltration are particularly notable. PMID:18078396

  1. Probe measurements in thermal plasma jets

    Microsoft Academic Search

    M. Brossa; E. Pfender

    1988-01-01

    Measurements of composition, temperature, and velocity in atmospheric argon plasma jets are reported, using enthalpy probes. The plasma jets are generated by a commercial type plasma gun and the measurements are expected to be of particular interest for industrial applications such as plasma spraying. Emphasis has been on the central and downstream regions of the plasma flame. The entrainment of

  2. Disseminated intravascular coagulation in patients with solid tumors.

    PubMed

    Feinstein, Donald I

    2015-02-01

    Disseminated intravascular coagulation (DIC) is an occasional complication of solid tumors, usually identified at the time of presentation because of excessive bleeding, thromboembolic complications, or abnormal laboratory test results. The latter include an unexplained low platelet count, a low fibrinogen level, an elevated D-dimer level, and a prolonged prothrombin time. Prompt diagnosis and treatment of the underlying malignancy can result in resolution of the DIC. Further, if the tumor is responsive to chemotherapy, a reasonable median survival can also result. Excessive bleeding at presentation can be managed with platelet transfusions, cryoprecipitate, and fresh frozen plasma. Thromboembolic complications can be managed with continuous intravenous heparin and supportive platelet transfusions; cryoprecipitate can be used whenever necessary to support platelet and fibrinogen levels. On occasion, when excessive bleeding and venous thromboembolism occur together, placement of a vena cava filter is required, along with the administration of platelets and cryoprecipitate. PMID:25683828

  3. A DSMC Study of Low Pressure Argon Discharge

    NASA Technical Reports Server (NTRS)

    Hash, David B.; Meyyappan, Meyya; Arnold, James O. (Technical Monitor)

    1997-01-01

    Work toward a self-consistent plasma simulation using the DSMC (Direct Simulation Monte Carlo) method for examination of the flowfields of low-pressure high density plasma reactors is presented. Presently, DSMC simulations for these applications involve either treating the electrons as a fluid or imposing experimentally determined values for the electron number density profile. In either approach, the electrons themselves are not physically simulated. Self-consistent plasma DSMC simulations have been conducted for aerospace applications but at a severe computational cost due in part to the scalar architectures on which the codes were employed. The present work attempts to conduct such simulations at a more reasonable cost using a plasma version of the object-oriented parallel Cornell DSMC code, MONACO, on an IBM SP-2. Due to availability of experimental data, the GEC reference cell is chosen to conduct preliminary investigations. An argon discharge is chosen to conduct preliminary investigations. An argon discharge is examined thus affording a simple chemistry set with eight gas-phase reactions and five species: Ar, Ar(+), Ar(*), Ar(sub 2), and e where Ar(*) is a metastable.

  4. Effect of coagulants on the fouling and performance of ultrafiltration (UF) membranes

    Microsoft Academic Search

    Yan Wang; Xiuming Xu; V. Jegatheesan; Baoyu Gao

    2009-01-01

    The combined coagulation and ultrafiltration (UF) system (C-UF system) is an advanced technology to treat natural organic matter (NOM) present in water. Traditional coagulants—prehydrolyzed inorganic coagulants, organic coagulants and composite coagulants were chosen to treat synthetic water containing humic acid (HA) in order to find an efficient coagulant that could remove NOM from the water effectively. The fouling, removal efficiency

  5. RBF neural network predictive control for coagulant dosage

    Microsoft Academic Search

    Li Wang

    2004-01-01

    Coagulant control plays an important role in water treatment process. Considering the nonlinear and time-delaying property of coagulation, a model of coagulant dosage based on RBF neural network is developed. The Gaussian function is used for hidden note function, whose centers are adjusted by K-means clustering algorithm. The weights of output layer are obtained based on RLS. The model has

  6. Coagulation factor VII variants resistant to inhibitory antibodies.

    PubMed

    Branchini, Alessio; Baroni, Marcello; Pfeiffer, Caroline; Batorova, Angelika; Giansily-Blaizot, Muriel; Schved, Jean F; Mariani, Guglielmo; Bernardi, Francesco; Pinotti, Mirko

    2014-11-01

    Replacement therapy is currently used to prevent and treat bleeding episodes in coagulation factor deficiencies. However, structural differences between the endogenous and therapeutic proteins might increase the risk for immune complications. This study was aimed at identifying factor (F)VII variants resistant to inhibitory antibodies developed after treatment with recombinant activated factor VII (rFVIIa) in a FVII-deficient patient homozygous for the p.A354V-p.P464Hfs mutation, which predicts trace levels of an elongated FVII variant in plasma. We performed fluorescent bead-based binding, ELISA-based competition as well as fluorogenic functional (activated FX and thrombin generation) assays in plasma and with recombinant proteins. We found that antibodies displayed higher affinity for the active than for the zymogen FVII (half-maximal binding at 0.54 ± 0.04 and 0.78 ± 0.07 BU/ml, respectively), and inhibited the coagulation initiation phase with a second-order kinetics. Isotypic analysis showed a polyclonal response with a large predominance of IgG1. We hypothesised that structural differences in the carboxyl-terminus between the inherited FVII and the therapeutic molecules contributed to the immune response. Intriguingly, a naturally-occurring, poorly secreted and 5-residue truncated FVII (FVII-462X) escaped inhibition. Among a series of truncated rFVII molecules, we identified a well-secreted and catalytically competent variant (rFVII-464X) with reduced binding to antibodies (half-maximal binding at 0.198 ± 0.003 BU/ml) as compared to the rFVII-wt (0.032 ± 0.002 BU/ml), which led to a 40-time reduced inhibition in activated FX generation assays. Taken together our results provide a paradigmatic example of mutation-related inhibitory antibodies, strongly support the FVII carboxyl-terminus as their main target and identify inhibitor-resistant FVII variants. PMID:25104096

  7. The effect of estrogen replacement therapy with or without progestogen on the fibrinolytic system and coagulation inhibitors in postmenopausal status

    Microsoft Academic Search

    Juan Gilabert; Amparo Estellés; Antonio Cano; Francisco España; Rosa Barrachina; Salvador Grancha; Justo Aznar; Miguel Tortajada

    1995-01-01

    OBJECTIVE: The aim of this study was to analyze several fibrinolytic components and coagulation inhibitors in postmenopausal women and to evaluate the effect of hormone replacement therapy.STUDY DESIGN: Several hemostatic parameters were evaluated in 75 postmenopausal women before and after 3 to 4 and 12 months of hormone therapy.RESULTS: An increase in plasma fibrinolytic activity primarily related to a significant

  8. Alveolar rhabdomyosarcoma presenting as subacute intravascular coagulation.

    PubMed Central

    Eldor, A; Naparstek, E; Boss, J H; Biran, S

    1977-01-01

    A patient with rhabdomyosarcoma is described in whom the presenting clinical and laboratory features were those of disseminated intravascular coagulation. The patient's rapid downhill course was primarily expressed by haemorrhagic tendency. An alveolar rhabdomyosarcoma, affecting many organs, including vascular and cardiac lumina, was found at necropsy and was considered to be the cause of the consumption coagulopathy. Images PMID:886020

  9. Interaction between the coagulation and complement system.

    PubMed

    Amara, Umme; Rittirsch, Daniel; Flierl, Michael; Bruckner, Uwe; Klos, Andreas; Gebhard, Florian; Lambris, John D; Huber-Lang, Markus

    2008-01-01

    The complement system as a main column of innate immunity and the coagulation system as a main column in hemostasis undergo massive activation early after injury. Interactions between the two cascades have often been proposed but the precise molecular pathways of this interplay are still in the dark. To elucidate the mechanisms involved, the effects of various coagulation factors on complement activation and generation of anaphylatoxins were investigated and summarized in the light of the latest literature. Own in vitro findings suggest, that the coagulation factors FXa, FXIa and plasmin may cleave both C5 and C3, and robustly generate C5a and C3a (as detected by immunoblotting and ELISA). The produced anaphylatoxins were found to be biologically active as shown by a dose-dependent chemotactic response of neutrophils and HMC-1 cells, respectively. Thrombin did not only cleave C5 (Huber-Lang et al. 2006) but also in vitro-generated C3a when incubated with native C3. The plasmin-induced cleavage activity could be dose-dependently blocked by the serine protease inhibitor aprotinin and leupeptine. These findings suggest that various serine proteases belonging to the coagulation system are able to activate the complement cascade independently of the established pathways. Moreover, functional C5a and C3a are generated, both of which are known to be crucially involved in the inflammatory response. PMID:19025115

  10. Ophthalmic complications with disseminated intravascular coagulation

    Microsoft Academic Search

    R. B. Patchett; W. B. Wilson; P. P. Ellis

    1988-01-01

    Massive lid oedema, ecchymosis, proptosis with a total restriction of extraocular movement, markedly raised intraocular pressure, and occlusion of the central retinal artery developed acutely in the right eye of a 26-year-old woman with a past history of disseminated intravascular coagulation. She had been admitted to hospital for symptoms of abdominal pain and bleeding from multiple sites a few hours

  11. The rarer inherited coagulation disorders: A review

    Microsoft Academic Search

    P. H. B. Bolton-Maggs; F. G. H. Hill

    1995-01-01

    Of the inherited bleeding disorders, haemophilia A, haemophilia B and von Willebrand's disease make up together well over 80% of those registered with the UK Haemophilia Centre Directors. The common simple screening tests of coagulation may overlook some of the more rare disorders and it is clearly important that such uncommon bleeding disorders are excluded during the course of the

  12. Properties of argon-lithium discharges in a microwave resonant cavity

    SciTech Connect

    Brooks, C.B.; Brake, M.L.; Gilgenback, R.M. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Nuclear Engineering

    1994-12-31

    A newly constructed microwave resonant cavity ion source will be used for laser-enhanced isotopic enrichment studies. The apparatus designed and tested in this work is smaller scale and uses an efficient microwave plasma ion source. This Asmussen-type source makes use of permanent rare-earth magnets to produce an electron cyclotron resonant region, making it more efficient for heating the plasma and allowing low pressure discharges to be maintained. A copper vapor laser pumped tunable dye laser will provide light for the excitation of the isotope to be enriched. The excited isotope will then be preferentially ionized and removed from the discharge chamber with a biased grid. In preparation for the isotopic enrichment studies, argon and argon-lithium discharges have been created and studied using well established plasma diagnostic techniques including Langmuir probe and optical emission spectroscopy. Plasma breakdown and operating conditions will be given for argon and argon-lithium discharges. Scalability of plasma parameters with input power, gas pressure and flow rate, and lithium concentration will be given. These results of preliminary studies will be shown along with an overview of the application for which the device is intended.

  13. Diamond electrodes modified by argon ion bombardment

    NASA Astrophysics Data System (ADS)

    Foord, John S.; Goeting, Christiaan H.

    2004-09-01

    The electrochemical properties of boron-doped chemical vapour deposited diamond films following argon ion bombardment are investigated. The argon ion treatments used produce defects at the electrode surface, but are below the amorphisation threshold for this material, and indeed can be readily reversed by sample annealing. Photoemission studies indicate downwards band-bending of about 0.8 eV as a result of the argon ion treatment, and the photoemission spectra and associated energy loss spectra are used to examine the changes occurring. The higher argon ion exposures to the surface are found to very significantly degrade the electrochemical characteristics of diamond. However for smaller ion doses, the electrochemical properties of some redox couples are not influenced by the argon ion treatments used, whereas others are strongly inhibited. The work therefore demonstrates that argon ion bombardment can be used to selectively modify the properties of diamond electrodes.

  14. Could light meal jeopardize laboratory coagulation tests?

    PubMed Central

    Lima-Oliveira, Gabriel; Salvagno, Gian Luca; Lippi, Giuseppe; Danese, Elisa; Gelati, Matteo; Montagnana, Martina; Picheth, Geraldo; Guidi, Gian Cesare

    2014-01-01

    Background: Presently the necessity of fasting time for coagulation tests is not standardized. Our hypothesis is that this can harm patient safety. This study is aimed at evaluating whether a light meal (i.e. breakfast) can jeopardize laboratory coagulation tests. Materials and methods: A blood sample was firstly collected from 17 fasting volunteers (12 h). Immediately after blood collection, the volunteers consumed a light meal. Then samples were collected at 1, 2 and 4 h after the meal. Coagulation tests included: activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen (Fbg), antithrombin III (AT), protein C (PC) and protein S (PS). Differences between samples were assessed by Wilcoxon ranked-pairs test. The level of statistical significance was set at P < 0.05. Mean % differences were determined and differences between and baseline and 1, 2 and 4h samples were compared with reference change value (RCV). Results: A significantly higher % activity of AT was observed at 1 h and 4 h after meal vs. baseline specimen [113 (104–117) and 111 (107–120) vs. 109 (102–118), respectively; P = 0.029 and P = 0.016]. APTT at 2 h was found significantly lower than baseline samples [32.0 (29.9–34.8) vs. 34.1 (32.2–35.2), respectively; P = 0.041]. The results of both Fbg and PS tests were not influenced by a light meal. Furthermore, no coagulation tests had significant variation after comparison with RCV. Conclusion: A light meal does not influence the laboratory coagulation tests we assessed, but we suggest that the laboratory quality managers standardize the fasting time for all blood tests at 12 hours, to completely metabolize the lipids intake. PMID:25351352

  15. Dusty plasmas

    SciTech Connect

    Jones, M.E.; Winske, D.; Keinigs, R.; Lemons, D.

    1996-05-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project has been to develop a fundamental understanding of dusty plasmas at the Laboratory. While dusty plasmas are found in space in galactic clouds, planetary rings, and cometary tails, and as contaminants in plasma enhanced fabrication of microelectronics, many of their properties are only partially understood. Our work has involved both theoretical analysis and self-consistent plasma simulations to understand basic properties of dusty plasmas related to equilibrium, stability, and transport. Such an understanding can improve the control and elimination of plasma dust in industrial applications and may be important in the study of planetary rings and comet dust tails. We have applied our techniques to the study of charging, dynamics, and coagulation of contaminants in plasma processing reactors for industrial etching and deposition processes and to instabilities in planetary rings and other space plasma environments. The work performed in this project has application to plasma kinetics, transport, and other classical elementary processes in plasmas as well as to plasma waves, oscillations, and instabilities.

  16. Determining the electron temperature and the electron density by a simple collisional-radiative model of argon and xenon in low-pressure discharges

    NASA Astrophysics Data System (ADS)

    Zhu, Xi-Ming; Chen, Wen-Cong; Li, Jiang; Pu, Yi-Kang

    2009-01-01

    A simple collisional-radiative model for argon and xenon is used, in conjunction with optical emission spectroscopy (line-ratio technique), to determine the electron temperature and electron density in low-pressure discharges containing argon and xenon. Satisfactory agreement is obtained between this method and the Langmuir probe for an inductively coupled plasma containing neon, argon and xenon. This method is applied for a capacitive discharge containing fluorocarbon, argon and xenon. The electron temperatures and electron densities obtained under various discharge conditions are compared with those reported in the literature by other techniques.

  17. Effects Of Continuous Argon Laser Irradiation On Canine And Autopsied Human Cardiac Tissue

    NASA Astrophysics Data System (ADS)

    Ben-Shachar, Giora; Sivakoff, Mark; Bernard, Steven L.; Dahms, Beverly B.; Riemenschneider, Thomas A.

    1984-10-01

    In eight human formalin preserved cardiac specimens, various cardiac and vascular obstructions were relieved by argon laser irradiation. Interatrial communication was also produced by a transar'rial approach in a live dog. In-vivo fresh canine cardiac tissues required power density of at feast 80, 90, and 110 watts/cm2 for vaporization of myocardial, vascular and valvular tissues respectively. The fiber tip to tissue distance (effective irradiation distance) for effective vaporization was less than I mm for vascular and valvular tissues and less than 4 mm for myocardium. Light microscopy showed four zones of histological damage common to all tissues - central crater surrounded by layers of charring, vacuolization and coagulation necorsis. Myocardium showed additionally a layer of normal appearing muscle cells (skip area) surrounded by a peripheral coagulation halo. Laser irradiation effects on valvular tissue showed the most lateral extension of coagulation necrosis. It is concluded that palliation and treatment of certain congenital heart defects by laser irradiation is anatomi-cally feasible and may be safe for in vivo application when low power output and short exposure time are used from a very short irradiation distance.

  18. Liquid Argon Calorimetry for ATLAS

    NASA Astrophysics Data System (ADS)

    Robinson, Alan

    2008-05-01

    This summer, the largest collaborative physics project since the Manhattan project will go online. One of four experiments for the Large Hadron Collider at CERN in Geneva, ATLAS, employs over 2000 people. Canadians have helped design, construct, and calibrate the liquid argon calorimeters for ATLAS to capture the products of the high energy collisions produced by the LHC. From an undergraduate's perspective, explore how these calorimeters are made to handle their harsh requirement. From nearly a billion proton-proton collisions a second, physicists hope to discover the Higgs boson and other new fundamental particles.

  19. Effect of argon ion bombardment on amorphous silicon carbonitride films

    NASA Astrophysics Data System (ADS)

    Batocki, R. G. S.; Mota, R. P.; Honda, R. Y.; Santos, D. C. R.

    2014-04-01

    Amorphous silicon carbonitride (a-SiCN:H) films were synthesized by radiofrequency (RF) Plasma Enhanced Vapor Chemical Deposition (PECVD) using hexamethyldisilazane (HMDSN) as precursor compound. Then, the films were post-treated by Plasma Immersion Ion Implantation (PIII) in argon atmosphere from 15 to 60 min. The hardness of the film enhanced after ion implantation, and the sample treated at 45 min process showed hardness greater than sixfold that of the untreated sample. This result is explained by the crosslinking and densification of the structure. Films were exposed to oxygen plasma for determining of the etching rate. It decreased monotonically from 33 Å/min to 19 Å/min for the range of process time, confirming structural alterations. Hydrophobic character of the a-SiCN:H films were modified immediately after ion bombardment, due to incorporation of polar groups. However, the high wettability of the films acquired by the ion implantation was diminished after aging in air. Therefore, argon PIII made a-SiCN:H films mechanically more resistant and altered their hydrophobic character.

  20. Fast and interrupted expansion in cyclic void growth in dusty plasma

    NASA Astrophysics Data System (ADS)

    van de Wetering, F. M. J. H.; Brooimans, R. J. C.; Nijdam, S.; Beckers, J.; Kroesen, G. M. W.

    2015-01-01

    Low-pressure acetylene plasmas are able to spontaneously form dust particles. This will result in a dense cloud of solid particles that is levitated in the plasma. The formed particles can grow up to micrometers. We observed a spontaneous interruption in the expansion of the so-called dust void. A dust void is a macroscopic region in the plasma that is free of nanoparticles. The phenomenon is periodical and reproducible. We refer to the expansion interruption as ‘hiccup’. The expanding void is an environment in which a new cycle of dust particle formation can start. At a certain moment in time, this cycle reaches the (sudden) coagulation phase and as a result the void will temporarily shrink. To substantiate this reasoning, the electron density is determined non-intrusively using microwave cavity resonance spectroscopy. Moreover, video imaging of laser light scattering of the dust particles provides their spatial distribution. The emission intensity of a single argon transition is measured similarly. Our results support the aforementioned hypothesis for what happens during the void hiccup. The void dynamics preceding the hiccup are modeled using a simple analytical model for the two dominant forces (ion drag and electric) working on a nanoparticle in a plasma. The model results qualitatively reproduce the measurements.

  1. The coagulation characteristics of humic acid by using acid-soluble chitosan, water-soluble chitosan, and chitosan coagulant mixtures.

    PubMed

    Chen, Chih-Yu; Wu, Chung-Yu; Chung, Ying-Chien

    2015-05-01

    Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This study compared the characteristics of humic acid (HA) removal by using acid-soluble chitosan, water-soluble chitosan, and coagulant mixtures of chitosan with aluminium sulphate (alum) or polyaluminium chloride (PACl). In addition, we evaluated their respective coagulation efficiencies at various coagulant concentrations, pH values, turbidities, and hardness levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants to identify the major factors affecting HA coagulation. The coagulation efficiency of acid- and water-soluble chitosan for 15?mg/l of HA was 74.4% and 87.5%, respectively. The optimal coagulation range of water-soluble chitosan (9-20?mg/l) was broader than that of acid-soluble chitosan (4-8?mg/l). Notably, acid-soluble chitosan/PACl and water-soluble chitosan/alum coagulant mixtures exhibited a higher coagulation efficiency for HA than for PACl or alum alone. Furthermore, these coagulant mixtures yielded an acceptable floc settling velocity and savings in both installation and operational expenses. Based on these results, we confidently assert that coagulant mixtures with a 1:1 mass ratio of acid-soluble chitosan/PACl and water-soluble chitosan/alum provide a substantially more cost-effective alternative to using chitosan alone for removing HA from water. PMID:25362971

  2. 21 CFR 868.1075 - Argon gas analyzer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 2013-04-01 false Argon gas analyzer. 868.1075 Section 868...DEVICES Diagnostic Devices § 868.1075 Argon gas analyzer. (a) Identification. An argon gas analyzer is a device intended to...

  3. 21 CFR 868.1075 - Argon gas analyzer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 2014-04-01 false Argon gas analyzer. 868.1075 Section 868...DEVICES Diagnostic Devices § 868.1075 Argon gas analyzer. (a) Identification. An argon gas analyzer is a device intended to...

  4. 21 CFR 868.1075 - Argon gas analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 2012-04-01 false Argon gas analyzer. 868.1075 Section 868...DEVICES Diagnostic Devices § 868.1075 Argon gas analyzer. (a) Identification. An argon gas analyzer is a device intended to...

  5. 21 CFR 868.1075 - Argon gas analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 2011-04-01 false Argon gas analyzer. 868.1075 Section 868...DEVICES Diagnostic Devices § 868.1075 Argon gas analyzer. (a) Identification. An argon gas analyzer is a device intended to...

  6. CERN, 23 October 2001 A prototype magnetized liquid Argon detector

    E-print Network

    McDonald, Kirk

    CERN, 23 October 2001 µ-LANNDD A prototype magnetized liquid Argon detector for electron charge Abstract A liquid Argon TPC detector immersed in magnetic field is proposed for systematic study...................................................................................................................................10 3. The liquid Argon TPC

  7. Numerical Study of a Free-Burning Argon Arc with Anode Melting

    Microsoft Academic Search

    Manabu Tanaka; Hidenori Terasaki; Masao Ushio; John J. Lowke

    2003-01-01

    Numerical modeling of free burning arcs and their electrodes is useful for clarifying the heat transfer phenomena in the welding process and to elucidate those effects which determine the weld penetration. This paper presents predictions for a stationary welding process by the free-burning argon arc. The whole region of the welding process, namely, tungsten cathode, arc plasma and stainless steel

  8. Observation of ? mode electron heating in dusty argon radio frequency discharges

    SciTech Connect

    Killer, Carsten; Bandelow, Gunnar; Schneider, Ralf; Melzer, André [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)] [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany); Matyash, Konstantin [Universitätsrechenzentrum, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)] [Universitätsrechenzentrum, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)

    2013-08-15

    The time-resolved emission of argon atoms in a dusty plasma has been measured with phase-resolved optical emission spectroscopy using an intensified charge-coupled device camera. For that purpose, three-dimensional dust clouds have been confined in a capacitively coupled rf argon discharge with the help of thermophoretic levitation. While electrons are exclusively heated by the expanding sheath (? mode) in the dust-free case, electron heating takes place in the entire plasma bulk when the discharge volume is filled with dust particles. Such a behavior is known as ? mode, first observed in electronegative plasmas. Furthermore, particle-in-cell simulations have been carried out, which reproduce the trends of the experimental findings. These simulations support previous numerical models showing that the enhanced atomic emission in the plasma can be attributed to a bulk electric field, which is mainly caused by the reduced electrical conductivity due to electron depletion.

  9. Liquid argon calorimetry for the SSC

    SciTech Connect

    Gordon, H.A.

    1990-01-01

    Liquid argon calorimetry is a mature technique. However, adapting it to the challenging environment of the SSC requires a large amount of R D. The advantages of the liquid argon approach are summarized and the issues being addressed by the R D program are described. 18 refs.

  10. Cryogenic air separation with cold argon recycle

    Microsoft Academic Search

    Erickerson

    1985-01-01

    The invention provides an efficient means of increasing oxygen purity and recovery and also argon recovery in cryogenic distillative air separation plants. In addition, the invention makes it possible to increase the oxygen delivery pressure from high efficiency triple pressure configurations without using an oxygen vacuum compressor. These advantages are obtained by incorporating an argon recycle compressor within the cold

  11. Nonequilibrium structure of argon shock waves

    Microsoft Academic Search

    H. F. Nelson

    1973-01-01

    This theoretical study investigates the influence of (1) the nonequilibrium excited state population in the relaxation region and (2) line radiation in the precursor on shock wave structure by considering strong shock waves propagating at Mach 18 and 24 into a theoretical argon-like gas at a pressure of 1 cm Hg and a temperature of 300 °K. The argon atom

  12. Insulin resistance syndrome: interaction with coagulation and fibrinolysis.

    PubMed

    Kohler, Hans-Peter

    2002-05-18

    Insulin resistance represents a common metabolic abnormality leading to cardiovascular disease, the major cause of morbidity and mortality in most parts of the world. Insulin resistance is also associated with an increased risk of type 2 diabetes which is strongly associated with obesity. The insulin resistance of obese people and subjects with type 2 diabetes is characterised by defects at many levels, affecting insulin receptor concentration, glucose transport mechanisms and the activities of intracellular enzymes. Around 25% of western populations show some features of the insulin resistance syndrome (often referred to as syndrome X or the metabolic syndrome) ie, a clustering of metabolic, atheromatous risk factors, including hypertriglyceridaemia, hyperinsulinaemia, hyper-tension, hypercholesterinaemia and obesity. However, the known metabolic cardiovascular risk factors associated with the insulin resistance syndrome do not sufficiently explain the excess vascular risk attributed to this syndrome. The observation, that increased plasma plasminogen activator inhibitor 1 (PAI-1) levels were associated with insulin resistance and atherothrombosis added for the first time a pathological basis for an association of the insulin resistance syndrome not only with metabolic, atheromatous (atherosclerotic) risk but also with atherothrombotic risk. It is very likely that not only PAI-1, but also other abnormalities in haemostatic variables contribute to this excess vascular risk. Knowledge of how haemostatic variables cluster with classical metabolic risk factors associated with the insulin resistance syndrome could help to better understand the pathogenesis of cardiovascular diseases. Indeed, many coagulation and fibrinolytic proteins have been shown to be associated with features of the insulin resistance syndrome and these associations suggest that some coagulation and fibrinolytic proteins have a role in atherothrombotic disorders, principally through an association with other established metabolic (atheromatous) risk factors in the presence of underlying insulin resistance. Interestingly, new therapeutic approaches in the prevention and treatment of insulin resistance do show some influence on coagulation and fibrinolysis. The newest drugs are the thiazolidinediones, a totally novel class of insulin sensitisers. They have the potential to offer improvements both in glycaemic control and in cardiovascular events. PMID:12148078

  13. Arsenic removal from drinking water during coagulation

    Microsoft Academic Search

    Janet G. Hering; Pen-Yuan Chen; Jennifer A. Wilkie; Menachem Elimelech

    1997-01-01

    The efficiency of arsenic removal from source waters and artificial freshwaters during coagulation with ferric chloride and alum was examined in bench-scale studies. Arsenic(V) removal by either ferric chloride or alum was relatively insensitive to variations in source water composition below pH 8. At pH 8 and 9, the efficiency of arsenic(V) removal by ferric chloride was decreased in the

  14. Patterned retinal coagulation with a scanning laser

    NASA Astrophysics Data System (ADS)

    Palanker, Daniel; Jain, ATul; Paulus, Yannis; Andersen, Dan; Blumenkranz, Mark S.

    2007-02-01

    Pan-retinal photocoagulation in patients with diabetic retinopathy typically involves application of more than 1000 laser spots; often resulting in physician fatigue and patient discomfort. We present a semi-automated patterned scanning laser photocoagulator that rapidly applies predetermined patterns of lesions; thus, greatly improving the comfort, efficiency and precision of the treatment. Patterns selected from a graphical user interface are displayed on the retina with an aiming beam, and treatment can be initiated and interrupted by depressing a foot pedal. To deliver a significant number of burns during the eye's fixation time, each pulse should be considerably shorter than conventional 100ms pulse duration. We measured coagulation thresholds and studied clinical and histological outcomes of the application of laser pulses in the range of 1-200ms in pigmented rabbits. Laser power required for producing ophthalmoscopically visible lesions with a laser spot of 132?m decreased from 360 to 37mW with pulse durations increasing from 1 to 100ms. In the range of 10-100ms clinically and histologically equivalent light burns could be produced. The safe therapeutic range of coagulation (ratio of the laser power required to produce a rupture to that for a light burn) decreased with decreasing pulse duration: from 3.8 at 100ms, to 3.0 at 20ms, to 2.5 at 10ms, and to 1.1 at 1ms. Histology demonstrated increased confinement of the thermal damage with shorter pulses, with coagulation zone limited to the photoreceptor layer at pulses shorter than 10ms. Durations of 10-20ms appear to be a good compromise between the speed and safety of retinal coagulation. Rapid application of multiple lesions greatly improves the speed, precision, and reduces pain in retinal photocoagulation.

  15. Blood coagulation factor VIII: An overview

    Microsoft Academic Search

    G. M. Bhopale; R. K. Nanda

    2003-01-01

    Factor VIII (FVIII) functions as a co-factor in the blood coagulation cascade for the proteolytic activation of factor X by\\u000a factor IXa. Deficiency of FVIII causes hemophilia A, the most commonly inherited bleeding disorder. This review highlights\\u000a current knowledge on selected aspects of FVIII in which both the scientist and the clinician should be interested.

  16. Hematological studies on naturally occurring substances. II. Effects of animal crude drugs on blood coagulation and fibrinolysis systems.

    PubMed

    Wang, J D; Narui, T; Kurata, H; Takeuchi, K; Hashimoto, T; Okuyama, T

    1989-08-01

    The effects of 112 extracts prepared from 37 kinds of animal crude drugs and a dog's filaria were investigated on the blood coagulation and fibrinolysis systems in vitro. The plasma recalcification time method was employed for the assay of blood coagulation and fibrinolytic activity was tested by the fibrin plate method. It was found that the water extracts of Bombyx Batryticatus, Carpio Fel and Holotrichiae Vermiculus showed potent inhibitory effects on blood coagulation. The methanol extracts of Phocae Thstis et Penis, Scorpion and Tabanus were promotive effect, on the other hand. As regards the fibrinolysis system, the water extracts of Agkistrodon, Lumbricus, Hirudo, Scolopendra and Scorpion and the methanol extract of Hirudo showed a remarkable activity. PMID:2598329

  17. Cardiovascular and blood coagulative effects of pulmonary zinc exposure

    SciTech Connect

    Gilmour, Peter S. [Center for Environmental Medicine, Asthma and Lung Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States); Nyska, Abraham [Laboratory of Experimental Pathology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 (United States); Schladweiler, Mette C. [Pulmonary Toxicology Branch, MD B143-01, Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, ORD, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); McGee, John K. [Pulmonary Toxicology Branch, MD B143-01, Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, ORD, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Wallenborn, J. Grace [Department of Environmental Sciences and Engineering, UNC School of Public Health, Chapel Hill, NC 27599 (United States); Richards, Judy H. [Pulmonary Toxicology Branch, MD B143-01, Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, ORD, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Kodavanti, Urmila P. [Pulmonary Toxicology Branch, MD B143-01, Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, ORD, US Environmental Protection Agency, Research Triangle Park, NC 27711 (United States)]. E-mail: kodavanti.urmila@epa.gov

    2006-02-15

    Cardiovascular damage induced by pulmonary exposure to environmental chemicals can result from direct action or, secondarily from pulmonary injury. We have developed a rat model of pulmonary exposure to zinc to demonstrate cardiac, coagulative, and fibrinolytic alterations. Male Wistar Kyoto rats were instilled intratracheally with saline or zinc sulfate, 131 {mu}g/kg (2 {mu}mol/kg); the alterations were determined at 1, 4, 24, and 48 h postexposure. High-dose zinc enabled us to show changes in circulating levels of zinc above normal and induce significant pulmonary inflammation/injury such that cardiac impairments were likely. At 1-24 h postexposure, plasma levels of zinc increased to nearly 20% above the base line. Significant pulmonary inflammation and injury were determined by analysis of bronchoalveolar lavage fluid and histopathology in zinc-exposed rats at all time points. Starting at 4 h postexposure, pulmonary damage was accompanied by persistently increased gene expressions of tissue factor (TF) and plasminogen activator-inhibitor-1 (PAI-1), but not thrombomodulin (TM). Cardiac tissues demonstrated similar temporal increases in expressions of TF, PAI-1, and TM mRNA following pulmonary instillation of zinc. In contrast to extensive pulmonary edema and inflammation, only mild, and focal acute, myocardial lesions developed in a few zinc-exposed rats; no histological evidence showed increased deposition of fibrin or disappearance of troponin. At 24 and 48 h postexposure to zinc, increases occurred in levels of systemic fibrinogen and the activated partial thromboplastin time. These data suggest that cardiovascular blood coagulation impairments are likely following pulmonary zinc exposure and associated pulmonary injury and inflammation.

  18. Can dust coagulation trigger streaming instability?

    NASA Astrophysics Data System (ADS)

    Dr??kowska, J.; Dullemond, C. P.

    2014-12-01

    Context. Streaming instability can be a very efficient way of overcoming growth and drift barriers to planetesimal formation. However, it was shown that strong clumping, which leads to planetesimal formation, requires a considerable number of large grains. State-of-the-art streaming instability models do not take into account realistic size distributions resulting from the collisional evolution of dust. Aims: We investigate whether a sufficient quantity of large aggregates can be produced by sticking and what the interplay of dust coagulation and planetesimal formation is. Methods: We develop a semi-analytical prescription of planetesimal formation by streaming instability and implement it in our dust coagulation code based on the Monte Carlo algorithm with the representative particles approach. Results: We find that planetesimal formation by streaming instability may preferentially work outside the snow line, where sticky icy aggregates are present. The efficiency of the process depends strongly on local dust abundance and radial pressure gradient, and requires a super-solar metallicity. If planetesimal formation is possible, the dust coagulation and settling typically need ~100 orbits to produce sufficiently large and settled grains and planetesimal formation lasts another ~1000 orbits. We present a simple analytical model that computes the amount of dust that can be turned into planetesimals given the parameters of the disk model.

  19. Heparanase and Coagulation–New Insights

    PubMed Central

    Nadir, Yona

    2014-01-01

    Heparanase, a ?-D-endoglucuronidase abundant in platelets that was discovered 30 years ago, is an enzyme that cleaves heparan sulfate side chains on the cell surface and in the extracellular matrix. It was later recognized as being a pro-inflammatory and pro-metastatic protein. We had earlier demonstrated that heparanase may also affect the hemostatic system in a non-enzymatic manner. We had shown that heparanase up-regulated the expression of the blood coagulation initiator tissue factor (TF) and interacted with the tissue factor pathway inhibitor (TFPI) on the cell surface membrane of endothelial and tumor cells, leading to dissociation of TFPI and resulting in increased cell surface coagulation activity. Moreover, we have demonstrated that heparanase directly enhanced TF activity which led to increased factor Xa production and subsequent activation of the coagulation system. Recently, heparanase inhibitory peptides derived of TFPI-2 were demonstrated by us to inhibit heparanase procoagulant activity and attenuate sepsis in mouse models. PMID:25386347

  20. Heparanase and coagulation-new insights.

    PubMed

    Nadir, Yona

    2014-10-01

    Heparanase, a ?-D-endoglucuronidase abundant in platelets that was discovered 30 years ago, is an enzyme that cleaves heparan sulfate side chains on the cell surface and in the extracellular matrix. It was later recognized as being a pro-inflammatory and pro-metastatic protein. We had earlier demonstrated that heparanase may also affect the hemostatic system in a non-enzymatic manner. We had shown that heparanase up-regulated the expression of the blood coagulation initiator tissue factor (TF) and interacted with the tissue factor pathway inhibitor (TFPI) on the cell surface membrane of endothelial and tumor cells, leading to dissociation of TFPI and resulting in increased cell surface coagulation activity. Moreover, we have demonstrated that heparanase directly enhanced TF activity which led to increased factor Xa production and subsequent activation of the coagulation system. Recently, heparanase inhibitory peptides derived of TFPI-2 were demonstrated by us to inhibit heparanase procoagulant activity and attenuate sepsis in mouse models. PMID:25386347

  1. Positive Feedback Loops for Factor V and Factor VII Activation Supply Sensitivity to Local Surface Tissue Factor Density During Blood Coagulation

    PubMed Central

    Balandina, A.N.; Shibeko, A.M.; Kireev, D.A.; Novikova, A.A.; Shmirev, I.I.; Panteleev, M.A.; Ataullakhanov, F.I.

    2011-01-01

    Blood coagulation is triggered not only by surface tissue factor (TF) density but also by surface TF distribution. We investigated recognition of surface TF distribution patterns during blood coagulation and identified the underlying molecular mechanisms. For these investigations, we employed 1), an in vitro reaction-diffusion experimental model of coagulation; and 2), numerical simulations using a mathematical model of coagulation in a three-dimensional space. When TF was uniformly immobilized over the activating surface, the clotting initiation time in normal plasma increased from 4 min to >120 min, with a decrease in TF density from 100 to 0.7 pmol/m2. In contrast, surface-immobilized fibroblasts initiated clotting within 3–7 min, independently of fibroblast quantity and despite a change in average surface TF density from 0.5 to 130 pmol/m2. Experiments using factor V-, VII-, and VIII-deficient plasma and computer simulations demonstrated that different responses to these two TF distributions are caused by two positive feedback loops in the blood coagulation network: activation of the TF–VII complex by factor Xa, and activation of factor V by thrombin. This finding suggests a new role for these reactions: to supply sensitivity to local TF density during blood coagulation. PMID:22004734

  2. Imaging of hydrogen halides photochemistry on argon and ice nanoparticles

    NASA Astrophysics Data System (ADS)

    Poterya, V.; Lengyel, J.; Pysanenko, A.; Svr?ková, P.; Fárník, M.

    2014-08-01

    The photodissociation dynamics of HX (X = Cl, Br) molecules deposited on large ArN and (H2O)N, bar{N}? 102-103, clusters is investigated at 193 nm using velocity map imaging of H and Cl photofragments. In addition, time-of-flight mass spectrometry after electron ionization complemented by pickup cross section measurements provide information about the composition and structure of the clusters. The hydrogen halides coagulate efficiently to generate smaller (HX)n clusters on ArN upon multiple pickup conditions. This implies a high mobility of HX molecules on argon. On the other hand, the molecules remain isolated on (H2O)N. The photodissociation on ArN leads to strong H-fragment caging manifested by the fragment intensity peaking sharply at zero kinetic energy. Some of the Cl-fragments from HCl photodissociation on ArN are also caged, while some of the fragments escape the cluster directly without losing their kinetic energy. The images of H-fragments from HX on (H2O)N also exhibit a strong central intensity, however, with a different kinetic energy distribution which originates from different processes: the HX acidic dissociation followed by H3O neutral hydronium radical formation after the UV excitation, and the slow H-fragments stem from subsequent decay of the H3O. The corresponding Cl-cofragment from the photoexcitation of the HCl.(H2O)N is trapped in the ice nanoparticle.

  3. Activation of the coagulation cascade after infusion of a factor XI concentrate in congenitally deficient patients.

    PubMed

    Mannucci, P M; Bauer, K A; Santagostino, E; Faioni, E; Barzegar, S; Coppola, R; Rosenberg, R D

    1994-08-15

    Virally inactivated, high-purity factor XI concentrates are available for treatment of patients with factor XI deficiency. However, preliminary experience indicates that some preparations may be thrombogenic. We evaluated whether a highly purified concentrate produced signs of activation of the coagulation cascade in two patients with severe factor XI deficiency infused before and after surgery. Signs of heightened enzymatic activity of the common pathway of coagulation (elevated plasma levels of prothrombin fragment 1 + 2 and fibrinopeptide A) developed in the early post-infusion period, accompanied by more delayed signs of fibrin formation with secondary hyperfibrinolysis (elevated D-dimer and plasmin-antiplasmin complex). These changes occurred in both patients, but were more severe in the older patient with breast cancer when she underwent surgery, being accompanied by fibrinogen and platelet consumption. There were no concomitant signs of heightened activity of the factor VII-tissue factor mechanism on the factor Xase complex (plasma levels of activated factor VII and of factor IX and X activation peptides did not increase). The observed changes in biochemical markers of coagulation activation indicate that concentrate infusions increased thrombin generation and activity and that such changes were magnified by malignancy and surgery. Because some factor XI concentrates may be thrombogenic, they should be used with caution, especially in patients with other risk factors for thrombosis. PMID:8049446

  4. Iron-enhanced coagulation is attenuated by chelation A thrombelastographic and ultrastructural analysis.

    PubMed

    Nielsen, Vance G; Pretorius, Etheresia

    2014-12-01

    Increased circulating ferritin and free iron have been found in a variety of disease states associated with thrombophilia. When blood or plasma is exposed to iron addition, characteristic changes in thrombus formation are observed by scanning electron microscopy, which include fusion of fibrin polymers, matting, and even sheeting of fibrin. A primary mechanism posited to explain iron-mediated hypercoagulability is hydroxyl radical formation and modification of fibrinogen; however, iron has also been demonstrated to bind to fibrinogen. We have recently demonstrated that iron enhances coagulation, manifested as a decrease in the time of onset of coagulation. Using clinically encountered concentrations of iron created by addition of FeCl3 to human plasma, we demonstrated that iron-mediated changes in reaction time determined by thrombelastography or changes in thrombus ultrastructure were significantly, but not completely, reversed by iron chelation with deferoxamine. Thus, reversible iron binding to fibrinogen mechanistically explains a significant portion of coagulation kinetic and ultrastructural hypercoagulability. Further investigation is needed to determine whether residual iron binding or other iron-mediated effects is responsible for hypercoagulability observed after chelation. PMID:24991945

  5. The effects of automated plasmapheresis on clinical, haematological, biochemical and coagulation variables in horses.

    PubMed

    Feige, K; Ehrat, F B; Kästner, S B R; Wampfler, B

    2005-01-01

    The goal of this study was to determine the effects of plasmapheresis on the behaviour, general condition, haematological, biochemical and coagulation variables of donor horses for 32 days following the procedure. Twenty millilitres of plasma/kg body weight were collected via plasmapheresis in six clinically healthy horses. The general behaviour and condition of the horses was not affected by the procedure. During plasmapheresis, there was a mild increase in the haematocrit, haemoglobin concentration and total erythrocyte and leucocyte counts (P < 0.01). The mean concentrations of total protein and albumin decreased significantly (P < 0.01) and total protein did not normalise for about three weeks. Several other biochemical variables also decreased significantly during plasmapheresis, but mostly remained within reference ranges. After plasmapheresis, the mean value of the activated partial thromboplastin time and the thrombin time were mildly but significantly increased (P < 0.01), and the mean activities of factor V, factor VIII and antithrombin decreased significantly (P < 0.01), although all coagulation values remained within reference ranges. Our results indicate that, in horses, the collection of 20 mL of plasma/kg body weight via plasmapheresis results in mild changes in several haematological, biochemical and coagulation variables, although these were of no clinical relevance for the donors. PMID:15683770

  6. Collisional radiative model of an argon atmospheric capillary surface-wave discharge

    Microsoft Academic Search

    A. Yanguas-Gil; J. Cotrino; A. R. González-Elipe

    2004-01-01

    The characteristics of a microwave surface-wave sustained plasma operated at atmospheric pressure in an open-ended dielectric tube are investigated theoretically as a first step in the development of a self-consistent model for these discharges. The plasma column is sustained in flowing argon. A surface-wave discharge that fills the whole radial cross section of the discharge tube is considered. With experimental

  7. Intranasal exposure to amorphous nanosilica particles could activate intrinsic coagulation cascade and platelets in mice

    PubMed Central

    2013-01-01

    Background Nanomaterials with particle sizes <100 nm have been already applied in various applications such as cosmetics, medicines, and foods. Therefore, ensuring the safety of nanomaterials is becoming increasingly important. Here we examined the localization and biological responses of intranasally administered amorphous nanosilica particles in mice, focusing on the coagulation system. Methods We used nanosilica particles with diameters of 30, 70, or 100 nm (nSP30, nSP70, or nSP100 respectively), and conventional microscale silica particles with diameters of 300 or 1000 nm (mSP300 or mSP1000, respectively). BALB/c mice were intranasally exposed to nSP30, nSP70, nSP100, mSP300, or mSP1000 at concentrations of 500 ?g/mouse for 7 days. After 24 hours of last administration, we performed the in vivo transmission electron microscopy analysis, hematological examination and coagulation tests. Results In vivo transmission electron microscopy analysis showed that nanosilica particles with a diameter <100 nm were absorbed through the nasal cavity and were distributed into liver and brain. Hematological examination and coagulation tests showed that platelet counts decreased and that the activated partial thromboplastin time was prolonged in nSP30 or nSP70-treated groups of mice, indicating that nanosilica particles might have activated a coagulation cascade. In addition, in in vitro activation tests of human plasma, nanosilica particles had greater potential than did conventional microscale silica particles to activate coagulation factor XII. In nanosilica-particle-treated groups, the levels of soluble CD40 ligand, and von Willebrand factor which are involved in stimulating platelets tended to slightly increase with decreasing particle size. Conclusions These results suggest that intranasally administered nanosilica particles with diameters of 30 and 70 nm could induce abnormal activation of the coagulation system through the activation of an intrinsic coagulation cascade. This study provides information to advance the development of safe and effective nanosilica particles. PMID:23958113

  8. plasmas

    NASA Astrophysics Data System (ADS)

    Zhang, H. Y.; Jin, C. G.; Yang, Y.; Ye, C.; Zhuge, L. J.; Wu, X. M.

    2014-12-01

    As-deposited HfO2 films were modified by CHF3, C4F8, and mixed C4F8/O2 plasmas in a dual-frequency capacitively coupled plasma chamber driven by radio frequency generators of 60 MHz as the high frequency (HF) source and 2 MHz as the low frequency source (60/2 MHz). The influences of various surface plasma treatments under CHF3, C4F8, and C4F8/O2 were investigated in order to understand the chemical and structural changes in thin-film systems, as well as their influence on the electrical properties. Fluorine atoms were incorporated into the HfO2 films by either CHF3 or C4F8 plasma treatment; meanwhile, the C/F films were formed on the surface of the HfO2 films. The formation of C/F layers decreased the k value of the gate stacks because of its low dielectric constant. However, the addition of O2 gas in the discharge gases suppressed the formation of C/F layers. After thermal annealing, tetragonal HfO2 phase was investigated in both samples treated with CHF3 and C4F8 plasmas. However, the samples treated with O-rich plasmas showed monoclinic phase, which indicated that the addition of O plasmas could influence the Hf/O ratio of the HfO2 films. The mechanism of the t-HfO2 formation was attributed to oxygen insufficiency generated by the incorporation of F atoms. The capacitors treated with C4F8/O2 plasmas displayed the highest k value, which ascribed that the C/F layers were suppressed and the tetragonal phase of HfO2 was formed. Good electrical properties, especially on the hysteresis voltage and frequency dispersion, were obtained because the bulk traps were passivated by the incorporation of F atoms. However, the H-related traps were generated during the CHF3 plasma treatments, which caused the performance degradation. All the treated samples showed lower leakage current density than the as-deposited HfO2 films at negative bias due to the reduced trap-assisted tunneling by the incorporation of F to block the electrons transferring from metal electrode to the trap level.

  9. Glial reactions to argon laser photocoagulation injury in rabbit and rat retinas

    NASA Astrophysics Data System (ADS)

    Humphrey, Martin F.; Chu, Yi; Sharp, Claudia; Moore, Stephen; Mann, Krishna; Rakoczy, Piroska; Constable, Ian J.

    1996-04-01

    Argon laser photocoagulation is a standard and effective clinical technique for a variety of disease conditions. However there is evidence that coagulation produces more widespread alterations in the retina than the local scarring at the injury site. For example, in diabetic retinopathy multiple photocoagulations in the retinal periphery can control blood vessel growth in the central retina. Therefore we have studied the changes in retinal glial cells following photocoagulation using immunocytochemical techniques with an emphasis on the spread of cellular reactions by using whole, flatmounted retinal preparations. Muller glial cells do not normally express the cytoskeletal protein GFAP (glial fibrillary acidic protein) but do so after a variety of injuries. We found that there is a very widespread expression of GFAP by Muller cells even after very focal coagulations and that this persists for 1 - 1.5 months after coagulation. The microglial cells are primed to react to injury and can release very powerful effector molecules and we therefore also examined the microglial reaction to see whether it correlated with the Muller cell reaction. However, we found that the microglial response, in terms of anatomical changes, was very focally confined to regions of direct cellular injury. We also examined MHC II expression to see whether microglia expressed this activity related protein without anatomical changes but we found no evidence of wide spread changes. In summary we find that inflammatory reactions are very localized after coagulation but the macroglial changes are more widespread and therefore the distant effects of photocoagulation may be more related to macroglial reactions.

  10. [Hemorrhagic accidents of the new oral anticoagulants and coagulation assays].

    PubMed

    Samama, M M; Conard, J; Lillo-Le Louët, A

    2013-07-01

    New oral anticoagulants which specifically inhibit factor Xa (FXa) or thrombin (FIIa) do not require routine laboratory monitoring. However, they induce a state of hypocoagulation and increase the risk of bleeding. In some clinical situations, such as emergency surgery, hemorrhagic episodes, or recurrent stroke, coagulation monitoring may be useful. A significant number of publications have reported uncontrollable hemorrhagic complications and deaths in patients treated with these new anticoagulants. The selection of the most appropriate clotting assay is based on the drug used and the availability of the test. The new anticoagulants influence all global clot-based tests. Prothrombin time and partial thromboplastin time measured before and after treatment are considered as qualitative tests since they are not specific. Specific anti-Xa and anti-IIa assays are available and results can be expressed in nanogram per milliliter of plasma using calibrated plasmas containing well-established amounts of drug. The fact that there is no specific antidote to reverse the anticoagulant action of the new anticoagulants can impair management of hemorrhagic complications; clinical experience is still limited. Pro-hemostatic treatment with non-activated or activated prothrombin complexes (FEIBA(®)), or as a last recourse with FVIIa concentrates (NovoSeven(®)), has been used with variable results. Some suggestions for the management of patients with bleeding have been published but there is still little clinical evidence for these interventions. PMID:23790307

  11. Isotopic studies of therapeutic anticoagulation with a coagulating enzyme

    PubMed Central

    Bell, W. R.; Regoeczi, E.

    1970-01-01

    The kinetics of the depletion of plasma fibrinogen were studied in seven patients who received fibrinogen-131I 1 hr before an intravenous injection of the coagulating enzyme (CE) derived from the venom of the pit viper, Agkistrodon rhodostoma. Disappearance of the clottable radioactivity labeled fibrinogen from the circulation conformed to an exponential decay with an average half-life of 0.85 hr. The mean clearance rate for protein-bound radioactivity, composed of fibrinogen and it's split products, was 12% of the intravascular pool per hour. The breakdown products of fibrin produced by CE inhibited polymerization of fibrin in vitro. Studies in five patients performed between the 3rd and 10th day following the administration of CE revealed that the absolute catabolic rates of fibrinogen were subnormal initially, but gradually increased as the fibrinogen concentration returned to normal. In rabbits, after the administration of CE, regeneration of the fibrinogen pool was markedly prolonged. This delayed regeneration time was not influenced by an excess of antivenene, but rapid regeneration to pretreatment values of plasma fibrinogen was immediately initiated by stimulating fibrinogen synthesis with subcutaneous turpentine. PMID:5456799

  12. Tracking down contact activation - from coagulation in vitro to inflammation in vivo.

    PubMed

    de Maat, S; Tersteeg, C; Herczenik, E; Maas, C

    2014-06-01

    The contact system is a volatile and versatile enzyme system in blood plasma that responds to the presence of nonphysiological surface materials by spontaneous generation of enzymatic activity. In subsequent steps, it can trigger blood coagulation and is responsible for the generation of the proinflammatory peptide bradykinin. The physiological role of the contact system is presently unknown, but it is commonly used to trigger coagulation in a diagnostic setting. In this three-part review, we will first describe the molecular mechanisms that drive contact activation on nonphysiological materials. Next, we will summarize and compare a number of bioassays, which are commonly used to investigate the contact system in health and disease. Finally, we will discuss recent findings from both fundamental and clinical studies on the contributions of contact system to cardiovascular, infectious, and inflammatory disease. PMID:24750684

  13. Emission in argon and krypton at 147 nm excited by runaway-electron-induced diffusion discharge

    SciTech Connect

    Gerasimov, Gennadii N; Krylov, B E [Research Center 'Vavilov State Optical Institute', St.Petersburg (Russian Federation); Lomaev, Mikhail I; Rybka, D V; Tarasenko, Viktor F [Institute of High Current Electronics, Siberian Branch, Russian Academy of Sciences, Tomsk (Russian Federation)

    2010-05-26

    Plasma emission of a pulsed diffuse discharge produced at increased pressures due to the preionisation of the gap by runaway electrons is studied in argon, krypton, and xenon. Nanosecond voltage pulses with the amplitude {approx}220 kV were applied to the discharge gap. It is shown that the presence of xenon ({approx}0.01%) in argon and krypton leads to the emergence of high-power narrowband radiation at awavelength of 147 nm. It is assumed that this radiation belongs to the bands of heteronuclear molecules Xe*Ar and Xe*Kr.

  14. Control of disinfection by products formation potential by enhanced coagulation

    Microsoft Academic Search

    A. Mesdaghinia; M. T. Rafiee; F. Vaezi; A. Mahvi; A. Torabian; A. Ghasri

    Jar-test experiments were conducted to study enhanced coagulation effectiveness in removal of disinfection by products (DBPs) from Zayandehrud River at Isfahan Province-the center part of Iran- in 2004. In this study, the removal of suspended and colloidal particles and natural organic matter (NOM) at various coagulant doses and coagulation pHs was assessed through raw and treated water measurements of turbidity,

  15. Electron scattering from argon: Data evaluation and consistency

    NASA Astrophysics Data System (ADS)

    Gargioni, E.; Grosswendt, B.

    2008-04-01

    The demand for coherent scattering data for modeling electron transport in matter has increased in recent years. While much effort has been devoted to the improvement of models describing electron transport and scattering, the updating of fundamental data sets on the basis of recent experimental results has often been neglected. The use of a well-validated set of electron cross sections ensures accurate calculations of transport parameters and ionization yields, with typical applications in material analysis, detector response studies, plasma diagnostics, physics of the atmosphere, and radiotherapy. Data consistency can be verified on the basis of various theoretical requirements, and systematic errors can be minimized by cross-checking results obtained from independent experiments. For example, the oscillator strength distribution of an atom can be obtained both from photoabsorption experiments and from zero-angle electron-atom collisions at high energy, on the basis of the Bethe theory. A considerable number of all electron-scattering experiments are concerned with light noble gases, in particular with argon. This gas is a dominant constituent of noble-gas discharge plasmas and plays an important role in rare-gas halide lasers and proportional scintillator counters. This work reviews electron-scattering cross sections and optical data for the argon atom, discusses the progress made in the field of electron scattering and photoabsorption, and focuses on the most appropriate criteria for verifying data consistency.

  16. Heat transfer to a single particle exposed to a thermal plasma

    Microsoft Academic Search

    Xi Chen; E. Pfender

    1982-01-01

    This paper is concerned with an analytical study of the heat and mass transfer process of a single particle exposed to a thermal plasma, with emphasis on the effects which evaporation imposes on heat transfer from the plasma to the particle. The results refer mainly to an atmospheric-pressure argon plasma and, for comparison purposes, an argon-hydrogen mixture and a nitrogen

  17. Recovery of struvite via coagulation and flocculation using natural compounds.

    PubMed

    Latifian, Maryam; Liu, Jing; Mattiasson, Bo

    2014-01-01

    One of the major setbacks of struvite recovery processes is the difficulty in harvesting struvite crystals. This study evaluates the use of different coagulants to improve precipitation of struvite (MgNH4PO4.6H20) crystals. Chitosan and poly(diallyldimethyl ammonium chloride) (Poly-DADMAC) as a coagulant-flocculent and alginate and bentonite as a coagulant aid have been examined in jar tests. Also, a continuous three-phase process, i.e., struvite crystallization, coagulation/flocculation and precipitation process, was set up for real wastewater. Addition of chitosan as the coagulant and bentonite as the coagulant aid was significantly more efficient in forming struvite flocs in comparison to Poly-DADMAC alone or with coagulant aid, which did not show any positive effect. The calculated average settling velocity of struvite with chitosan-bentonite addition in synthetic and in real wastewater increased by approximately 5.3 and 2.8 folds, respectively, compared with that of no coagulant/flocculent addition. Phosphorus recovery of over 70% was achieved by the continuous process. Findings in this study clearly confirmed the possibility of using chitosan and bentonite as an efficient coagulant-flocculent to enhance the recovery of struvite crystals. PMID:25145182

  18. Compound bioflocculant and polyaluminum chloride in kaolin-humic acid coagulation: factors influencing coagulation performance and floc characteristics.

    PubMed

    Li, Ruihua; Gao, Baoyu; Huang, Xin; Dong, Hongyu; Li, Xiaochen; Yue, Qinyan; Wang, Yan; Li, Qian

    2014-11-01

    The objective of this study was to investigate the influence of coagulant dosage and pH on coagulation performance and floc properties using polyaluminum chloride (PAC) and compound bioflocculant (CBF) dual-coagulant in kaolin-humic acid (HA) treatment. Results showed that as PAC dosage rose, comparatively better coagulation efficiencies and floc characteristics were achieved due to stronger charge neutralization and sweeping effect. Addition of CBF could enhance coagulation performance and floc properties, including size, strength and recoverability, except fractal dimension. Solution pH had a significant effect on coagulation efficiencies and flocs formation. Under acidic condition, flocs showed higher strength and recoverability but lower fractal dimension, where charge neutralization was the foremost mechanism. More compact flocs were generated under alkaline condition due to the sweeping effect of hydrolyzed Al species. PMID:25218625

  19. Fusaric acid, a mycotoxin, and its influence on blood coagulation and platelet function.

    PubMed

    Devaraja, Sannaningaiah; Girish, Kesturu S; Santhosh, Martin S; Hemshekhar, Mahadevappa; Nayaka, Siddaiah C; Kemparaju, Kempaiah

    2013-06-01

    The current study intended to explore the effect of fusaric acid on blood coagulation including plasma coagulation and platelet aggregation. Fusaric acid exhibited biphasic effects on citrated human plasma recalcification time. At concentrations below 50 ng, fusaric acid decreased the clotting time of plasma dose-dependently from 130 ± 3s control value to 32 ± 3s; however, above 50 ng, fusaric acid increased the clotting time from 32 ± 3s and reached a maximum of 152 s at 100 ng and remained unaltered thereafter for the increased dose of fusaric acid. Fusaric acid without damaging red blood cells and platelets, inhibited agonists such as collagen, ADP, thrombin, and epinephrine-induced aggregation of both platelet-rich plasma (PRP) and washed platelets preparations of human. Interestingly, fusaric acid showed biphasic effects only in thrombin-induced platelet aggregation of washed platelets, and at lower concentration (below 900 ng) it activated platelet aggregation; however, in increased concentration (above 900 ng) it inhibited the platelet aggregation of washed platelets. In addition, fusaric acid also inhibited the agonist ADP-induced platelet aggregation of washed platelet suspension but did not show biphasic effect. Further, fusaric acid did not induce the platelets to generate reactive oxygen species (ROS) that clearly suggests that the induction of platelet function could be the result of the fusaric acid-mediated receptor interaction but not through the morphological shape change. PMID:23343693

  20. Dust-Induced Modulation of the Atomic Emission in a Dusty Argon Discharge

    SciTech Connect

    Huebner, S.; Melzer, A. [Institut fuer Physik, Ernst-Moritz-Arndt-Universitaet, D-17487 Greifswald (Germany)

    2009-05-29

    The spectral emission of argon atoms in a dusty rf discharge plasma has been determined. For that purpose, the spatially and temporally resolved emission of the argon atoms during the rf cycle was measured using a gated intensified charge-coupled device camera. While dust particles of 2-3 {mu}m diameter trapped in the sheath lead to an increased plasma emission during the sheath expansion phase, larger particles of 10-12 {mu}m diameter result in a decreased emission. This behavior is explained by the combined action of electron density reduction due to the charging dynamics in the sheath and the increase of electron temperature to compensate plasma losses at the dust.

  1. A microwave plasma cleaning apparatus

    NASA Technical Reports Server (NTRS)

    Tsai, C. C.; Nelson, W. D.; Schechter, D. E.; Thompson, L. M.; Glover, A. L.

    1995-01-01

    In a microwave electron cyclotron resonance plasma source, reactive plasmas of oxygen and its mixtures of argon have been used for evaluating plasma cleaning technologies. Small aluminum samples (0.95 x 1.9 cm) were coated with thin films (less than or equal to 20 micrometers in thickness) of Shell Vitrea oil and cleaned with reactive plasmas. The discharge parameters, such as gas pressure, magnetic field, substrate biasing, and microwave power, were varied to change cleaning conditions. A mass spectroscopy (or residual gas analyzer) was used to monitor the status of plasma cleaning. Mass loss of the samples after plasma cleaning was measured to estimate cleaning rates. Measured cleaning rates of low-pressure (0.5-m torr) argon/oxygen plasmas were as high as 2.7 micrometers/min. X-ray photoelectron spectroscopy was used to determine cleanliness of the sample surfaces. In this paper, significant results of the plasma cleaning are reported and discussed.

  2. Coagulation profile and platelet parameters of the Arabian sand gazelle (Gazella subgutturosa marica): comparison with humans and camels.

    PubMed

    Hussein, M F; Aljumaah, R S; Homeida, A M; Alhaidary, A A; Alshaikh, M A; Gar Elnabi, A; Mohammed, O B; Omer, Sawsan A; Macasero, W V

    2010-10-01

    During March 2009, we evaluated the hemostatic profile and platelet indices of 18 Arabian sand gazelles (Gazella subgutturosa marica) and compared the results with those from humans and camels (Camelus dromedarius). Gazelles and camels had shorter activated partial thromboplastin times, lower proconvertin and higher antihemophilic factor coagulation activity, and plasma fibrinogen levels than humans. Prothrombin time was longer in sand gazelles and shorter in camels than it was in humans. Plasma thromboplastin component, Stuart factor, and plasma thromboplastin antecedent were similar in gazelles, humans, and camels, whereas the platelet count of the sand gazelle was significantly higher than it was for camels and humans. PMID:20966267

  3. nanofibers in air and argon atmospheres

    NASA Astrophysics Data System (ADS)

    Albetran, H.; Haroosh, H.; Dong, Y.; Prida, V. M.; O'Connor, B. H.; Low, I. M.

    2014-07-01

    The effects of atmospheric air and argon environments on thermal-induced phase transformations in electrospun TiO2 nanofibers have been investigated in situ using synchrotron radiation diffraction. Diffraction results showed that the as-synthesized TiO2 nanofibers were initially amorphous, but crystallized to form anatase and rutile after thermal annealing in air or argon at elevated temperatures. The crystallization temperature of anatase was delayed by 100 °C in argon relative to in air, and the transformation of anatase into rutile occurs faster in argon atmosphere than in air due to the formation of oxygen vacancies. Non-linear strains formed in both polymorphs and the substantial elevation of rutile thermal expansion pointed to strain anisotropy in the rutile phase and the concomitant fibre breakage.

  4. Comparing the equivalent particle number density distribution of gas and plasma flow fields.

    PubMed

    Chen, Yun-yun; Zhang, Ying-ying; Zhang, Cheng-yi; Li, Zhen-hua

    2013-04-20

    In this paper, the equivalent particle number density distribution of gas and plasma flow fields is investigated. For the purpose of facilitating comparison, argon gas and argon arc plasma are chosen as practical examples for experiment. The equivalent particle number density distributions of the argon gas and argon arc plasma are reconstructed from the experimentally measured refractive index distributions obtained by moiré tomography, while five cross sections, which are 7, 8.5, 10, 11.5, and 13 mm away from the jet nozzle are chosen for practical calculation and comparison. In experiment, the probe wavelength and the export pressure of argon gas and argon arc plasma are the same. The experimental results manifest that (1) the equivalent particle number density decreases with the distance away from the jet nozzle of the gas flow field, while (2) the equivalent particle number density of the plasma flow field has a different variation. Finally, the experimental results are theoretically explained and analyzed. PMID:23669673

  5. Clinical aspects of ophthalmic argon laser

    SciTech Connect

    Zinn, K.M.

    1981-01-01

    This paper reviews the historical events leading to the development of the ophthalmic laser. The formation of the argon laser beam and its biological effects on ocular tissues are outlined, with the major emphasis on the retinal and choroidal tissues. The clinical indications, contraindications, and complications of ophthalmic argon laser photocoagulation for the anterior segment as well as the posterior segment structures of the eye are also thoroughly discussed.

  6. Electron mobility in argon and carbon dioxide

    Microsoft Academic Search

    Z. Kucerovsky

    2006-01-01

    Electron drift velocities were determined in argon and in mixtures of argon with carbon dioxide, using media processed to yield a high degree of purity. The measurements were performed at a pressure of 760 torr and a temperature of 25degC. The medium was confined in a cylindrical measuring chamber made of polytetrafluorethylene (10-mm diameter, 10-mm length). The electrodes used to

  7. Increased coagulation and suppressed generation of activated protein C in aged mice during intra-abdominal sepsis.

    PubMed

    Starr, Marlene E; Takahashi, Hitoshi; Okamura, Daiki; Zwischenberger, Brittany A; Mrazek, Amy A; Ueda, Junji; Stromberg, Arnold J; Evers, B Mark; Esmon, Charles T; Saito, Hiroshi

    2015-01-15

    Sepsis is a life-threatening clinical condition that is particularly serious among the elderly who experience considerably higher mortality rates compared with younger patients. Using a sterile endotoxemia model, we previously reported age-dependent mortality in conjunction with enhanced coagulation and insufficient levels of anti-coagulant factor activated protein C (aPC). The purpose of the present study was to further investigate the mechanisms for age-dependent coagulation and aPC insufficiency during experimental sepsis. Intra-abdominal sepsis was induced by cecal ligation and puncture (CLP) using 21 or 16 gauge (G) needles (double-puncture) on young (4 to 6 mo old) and aged (20 to 25 mo old) male C57BL/6 mice. When compared with young mice, aged mice showed significantly increased mortality (92% vs. 28%), systemic inflammation, and coagulation in the lung and kidney after 21G CLP. Young mice with more severe CLP (16G) showed a mortality rate and inflammation equivalent to aged mice with 21G CLP; however, enhanced coagulation and kidney dysfunction were significant only in the aged. In young mice, increased levels of aPC after CLP were coupled with reduced levels of protein C (PC), suggesting the conversion of PC to aPC; however, PC and aPC levels remained unchanged in aged mice, indicating a lack of PC to aPC conversion. Activation of fibrinolysis, determined by plasma d-dimer levels, was similar regardless of age or CLP severity, and plasminogen activator inhibitor-1, an inhibitor of fibrinolysis, showed severity-dependent induction independent of age. These results suggest that enhanced coagulation in aged mice during sepsis is due to dysfunction of the PC activation mechanism. PMID:25380813

  8. Contact Activation of Blood Plasma and Factor XII by Ion-exchange Resins

    PubMed Central

    Yeh, Chyi-Huey Josh; Dimachkie, Ziad O.; Golas, Avantika; Cheng, Alice; Parhi, Purnendu; Vogler, Erwin A.

    2011-01-01

    Sepharose ion-exchange particles bearing strong Lewis acid/base functional groups (sulfopropyl, carboxymethyl, quarternary ammonium, dimethyl aminoethyl, and iminodiacetic acid) exhibiting high plasma protein adsorbent capacities are shown to be more efficient activators of blood factor XII in neat-buffer solution than either hydrophilic clean-glass particles or hydrophobic octyl sepharose particles ( FXII?surfaceactivatorFXIIa; a.k.a autoactivation, where FXII is the zymogen and FXIIa is a procoagulant protease). In sharp contrast to the clean-glass standard of comparison, ion-exchange activators are shown to be inefficient activators of blood plasma coagulation. These contrasting activation properties are proposed to be due to the moderating effect of plasma-protein adsorption on plasma coagulation. Efficient adsorption of blood plasma proteins unrelated to the coagulation cascade impedes FXII contacts with ion-exchange particles immersed in plasma, reducing autoactivation, and causing sluggish plasma coagulation. By contrast, plasma proteins do not adsorb to hydrophilic clean glass and efficient autoactivation leads directly to efficient activation of plasma coagulation. It is also shown that competitive-protein adsorption can displace FXIIa adsorbed to the surface of ion-exchange resins. As a consequence of highly-efficient autoactivation and FXIIa displacement by plasma proteins, ion-exchange particles are slightly more efficient activators of plasma coagulation than hydrophobic octyl sepharose particles that do not bear strong Lewis acid/base surface functionalities but to which plasma proteins adsorb efficiently. Plasma proteins thus play a dual role in moderating contact activation of the plasma coagulation cascade. The principal role is impeding FXII contact with activating surfaces but this same effect can displace FXIIa from an activating surface into solution where the protease can potentiate subsequent steps of the plasma coagulation cascade. PMID:21982294

  9. Contact activation of blood plasma and factor XII by ion-exchange resins.

    PubMed

    Josh Yeh, Chyi-Huey; Dimachkie, Ziad O; Golas, Avantika; Cheng, Alice; Parhi, Purnendu; Vogler, Erwin A

    2012-01-01

    Sepharose ion-exchange particles bearing strong Lewis acid/base functional groups (sulfopropyl, carboxymethyl, quaternary ammonium, dimethyl aminoethyl, and iminodiacetic acid) exhibiting high plasma protein adsorbent capacities are shown to be more efficient activators of blood factor XII in neat-buffer solution than either hydrophilic clean-glass particles or hydrophobic octyl sepharose particles (FXII (activator)?(surface) FXIIa; a.k.a autoactivation, where FXII is the zymogen and FXIIa is a procoagulant protease). In sharp contrast to the clean-glass standard of comparison, ion-exchange activators are shown to be inefficient activators of blood plasma coagulation. These contrasting activation properties are proposed to be due to the moderating effect of plasma-protein adsorption on plasma coagulation. Efficient adsorption of blood-plasma proteins unrelated to the coagulation cascade impedes FXII contacts with ion-exchange particles immersed in plasma, reducing autoactivation, and causing sluggish plasma coagulation. By contrast, plasma proteins do not adsorb to hydrophilic clean glass and efficient autoactivation leads directly to efficient activation of plasma coagulation. It is also shown that competitive-protein adsorption can displace FXIIa adsorbed to the surface of ion-exchange resins. As a consequence of highly-efficient autoactivation and FXIIa displacement by plasma proteins, ion-exchange particles are slightly more efficient activators of plasma coagulation than hydrophobic octyl sepharose particles that do not bear strong Lewis acid/base surface functionalities but to which plasma proteins adsorb efficiently. Plasma proteins thus play a dual role in moderating contact activation of the plasma coagulation cascade. The principal role is impeding FXII contact with activating surfaces, but this same effect can displace FXIIa from an activating surface into solution where the protease can potentiate subsequent steps of the plasma coagulation cascade. PMID:21982294

  10. Pure eccentric exercise does not activate blood coagulation

    Microsoft Academic Search

    Thomas Hilberg; Doreen Gläser; Dagmar Prasa; Jörg Stürzebecher; Holger H. W. Gabriel

    2005-01-01

    Eccentric exercise can cause skeletal muscle damage with ultrastructural disruption, inflammation and increased proteolytic enzyme activity. It may be possible that these changes are able to trigger blood coagulation in vivo. The aim of the study was to investigate changes in blood coagulation via the measurement of aPTT, the thrombin potential (total [TTP] and endogenous [ETP], both intrinsic [in] and

  11. Analysis and optimization of coagulation and flocculation process

    NASA Astrophysics Data System (ADS)

    Saritha, V.; Srinivas, N.; Srikanth Vuppala, N. V.

    2015-02-01

    Natural coagulants have been the focus of research of many investigators through the last decade owing to the problems caused by the chemical coagulants. Optimization of process parameters is vital for the effectiveness of coagulation process. In the present study optimization of parameters like pH, dose of coagulant and mixing speed were studied using natural coagulants sago and chitin in comparison with alum. Jar test apparatus was used to perform the coagulation. The results showed that the removal of turbidity was up to 99 % by both alum and chitin at lower doses of coagulant, i.e., 0.1-0.3 g/L, whereas sago has shown a reduction of 70-100 % at doses of 0.1 and 0.2 g/L. The optimum conditions observed for sago were 6 and 7 whereas chitin was stable at all pH ranges, lower coagulant doses, i.e., 0.1-0.3 g/L and mixing speed—rapid mixing at 100 rpm for 10 min and slow mixing 20 rpm for 20 min. Hence, it can be concluded that sago and chitin can be used for treating water even with large seasonal variation in turbidity.

  12. Brain Neoplasms and Coagulation—Lessons from Heterogeneity

    PubMed Central

    D’Asti, Esterina; Fang, Yi; Rak, Janusz

    2014-01-01

    The coagulation system constitutes an important facet of the unique vascular microenvironment in which primary and metastatic brain tumors evolve and progress. While brain tumor cells express tissue factor (TF) and other effectors of the coagulation system (coagulome), their propensity to induce local and peripheral thrombosis is highly diverse, most dramatic in the case of glioblastoma multiforme (GBM), and less obvious in pediatric tumors. While the immediate medical needs often frame the discussion on current clinical challenges, the coagulation pathway may contribute to brain tumor progression through subtle, context-dependent, and non-coagulant effects, such as induction of inflammation, angiogenesis, or by responding to iatrogenic insults (e.g. surgery). In this regard, the emerging molecular diversity of brain tumor suptypes (e.g. in glioma and medulloblastoma) highlights the link between oncogenic pathways and the tumor repertoire of coagulation system regulators (coagulome). This relationship may influence the mechanisms of spontaneous and therapeutically provoked tumor cell interactions with the coagulation system as a whole. Indeed, oncogenes (EGFR, MET) and tumor suppressors (PTEN, TP53) may alter the expression, activity, and vesicular release of tissue factor (TF), and cause other changes. Conversely, the coagulant microenvironment may also influence the molecular evolution of brain tumor cells through selective and instructive cues. We suggest that effective targeting of the coagulation system in brain tumors should be explored through molecular stratification, stage-specific analysis, and more personalized approaches including thromboprophylaxis and adjuvant treatment aimed at improvement of patient survival. PMID:25386346

  13. Characteristics of nanosized polyaluminum chloride coagulant prepared by electrolysis process

    Microsoft Academic Search

    Hui-Juan Liu; Jiu-Hui Qu; Cheng-Zhi Hu; Su-Juan Zhang

    2003-01-01

    Polyaluminum chloride (PAC) has become a focus of many studies involving coagulation because of its advantages over traditional coagulants. In this study, a novel method involving an electrolysis process for preparing of PAC was developed. The products were characterized using 27Al NMR spectroscopy, dynamic light scattering (DLS) and transmission electron micrograph (TEM). Results indicated that the electrolysis process provided favorable

  14. MAGNESIUM CARBONATE - A RECYCLED COAGULANT FROM WATER TREATMENT. CAPSULE REPORT

    EPA Science Inventory

    This Capsule Report explains the new magnesium recycle coagulation system for water treatment, which is based on a combination of water softening and conventional coagulation techniques which can be applied to all types of water. This system offers an alternative approach to chem...

  15. Coagulation chemistries for silica removal from cooling tower water.

    SciTech Connect

    Nyman, May Devan; Altman, Susan Jeanne; Stewart, Tom

    2010-02-01

    The formation of silica scale is a problem for thermoelectric power generating facilities, and this study investigated the potential for removal of silica by means of chemical coagulation from source water before it is subjected to mineral concentration in cooling towers. In Phase I, a screening of many typical as well as novel coagulants was carried out using concentrated cooling tower water, with and without flocculation aids, at concentrations typical for water purification with limited results. In Phase II, it was decided that treatment of source or make up water was more appropriate, and that higher dosing with coagulants delivered promising results. In fact, the less exotic coagulants proved to be more efficacious for reasons not yet fully determined. Some analysis was made of the molecular nature of the precipitated floc, which may aid in process improvements. In Phase III, more detailed study of process conditions for aluminum chloride coagulation was undertaken. Lime-soda water softening and the precipitation of magnesium hydroxide were shown to be too limited in terms of effectiveness, speed, and energy consumption to be considered further for the present application. In Phase IV, sodium aluminate emerged as an effective coagulant for silica, and the most attractive of those tested to date because of its availability, ease of use, and low requirement for additional chemicals. Some process optimization was performed for coagulant concentration and operational pH. It is concluded that silica coagulation with simple aluminum-based agents is effective, simple, and compatible with other industrial processes.

  16. Shunt Revision by Coagulation with Retention of the Ventricular Catheter

    Microsoft Academic Search

    Roger J. Hudgins; William R. Boydston

    1998-01-01

    Intraluminal coagulation of a ventricular catheter followed by its removal and replacement is a technique used for proximal shunt revision. The authors describe experience leaving the original catheter in place when flow of CSF is established by the coagulation. Advantages of this modification include maintenance of ventricular access when the ventricles are small and the possibility of reducing the incidence

  17. Mathematical Modeling and Computer Simulation in Blood Coagulation

    Microsoft Academic Search

    Fazoil I. Ataullakhanov; Mikhail A. Panteleev

    2005-01-01

    Over the last two decades, mathematical modeling has become a popular tool in study of blood coagulation. The in silico methods were able to yield interesting and significant results in the understanding of both individual reaction mechanisms and regulation of large sections of the coagulation cascade. The objective of this paper is to review the development of theoretical research in

  18. Blood Coagulation Meter: A Low Cost Viscoelasticity based Approach

    Microsoft Academic Search

    B. Ghosh; B. Ramachandran; S. Anand; A. Salhan; L. D'Almeida

    2008-01-01

    Blood coagulation is an essential defense mechanism of the human body. In case of injury, it prevents excessive blood loss and reduces the chances of infection. In conditions like Hemophilia and von Willebrand's disease, clotting is insufficient. The coagulation process depends on certain clotting factors as well as the platelet count. A coagulometer is a device that measures the rate

  19. Effects of high-molecular-weight cryoprotectants on platelets and the coagulation system.

    PubMed

    Bakaltcheva, I; Ganong, J P; Holtz, B L; Peat, R A; Reid, T

    2000-06-01

    The objective of this study is to examine the effects of the most widely used high-molecular-weight cryoprotectants on the coagulation system. Dextran, hydryoxyethyl starch (HES), polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), and albumin were added at different concentrations in the range between 0.01-1% (w/v) to solvent/detergent-treated plasma. Using a STA/STA Compact coagulation analyzer the following clotting tests were performed: prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), Factor V, and Factor VIII percentage of activity. PVP and PEG caused a significant increase in APTT, a decrease in Factor VIII percentage of activity, and a slight decrease in TT, while PT and Factor V percentage of activity remained unchanged. Dextran, HES, and albumin did not effect the clotting tests. The effect of high-molecular-weight cryoprotectants on platelets was assessed by platelet-induced clot retraction (PICR) and aggregation with thrombin and agglutination with ristocetin. Platelet aggregation and agglutination were unaffected by all cryoprotectants tested; however, PICR was significantly reduced in the presence of PVP or PEG. Possible mechanisms by which PVP and PEG interfere with the coagulation system are discussed. We also raise issues concerning the development of one-step blood cryopreservation techniques which do not require cryoprotectant removal prior to transfusion. PMID:10924260

  20. Thrombin Activity Propagates in Space During Blood Coagulation as an Excitation Wave

    PubMed Central

    Dashkevich, N.M.; Ovanesov, M.V.; Balandina, A.N.; Karamzin, S.S.; Shestakov, P.I.; Soshitova, N.P.; Tokarev, A.A.; Panteleev, M.A.; Ataullakhanov, F.I.

    2012-01-01

    Injury-induced bleeding is stopped by a hemostatic plug formation that is controlled by a complex nonlinear and spatially heterogeneous biochemical network of proteolytic enzymes called blood coagulation. We studied spatial dynamics of thrombin, the central enzyme of this network, by developing a fluorogenic substrate-based method for time- and space-resolved imaging of thrombin enzymatic activity. Clotting stimulation by immobilized tissue factor induced localized thrombin activity impulse that propagated in space and possessed all characteristic traits of a traveling excitation wave: constant spatial velocity, constant amplitude, and insensitivity to the initial stimulation once it exceeded activation threshold. The parameters of this traveling wave were controlled by the availability of phospholipids or platelets, and the wave did not form in plasmas from hemophilia A or C patients who lack factors VIII and XI, which are mediators of the two principal positive feedbacks of coagulation. Stimulation of the negative feedback of the protein C pathway with thrombomodulin produced nonstationary patterns of wave formation followed by deceleration and annihilation. This indicates that blood can function as an excitable medium that conducts traveling waves of coagulation. PMID:23200057

  1. Task-Oriented Modular Decomposition of Biological Networks: Trigger Mechanism in Blood Coagulation

    PubMed Central

    Panteleev, Mikhail A.; Balandina, Anna N.; Lipets, Elena N.; Ovanesov, Mikhail V.; Ataullakhanov, Fazoil I.

    2010-01-01

    Abstract Analysis of complex time-dependent biological networks is an important challenge in the current postgenomic era. We propose a middle-out approach for decomposition and analysis of complex time-dependent biological networks based on: 1), creation of a detailed mechanism-driven mathematical model of the network; 2), network response decomposition into several physiologically relevant subtasks; and 3), subsequent decomposition of the model, with the help of task-oriented necessity and sensitivity analysis into several modules that each control a single specific subtask, which is followed by further simplification employing temporal hierarchy reduction. The technique is tested and illustrated by studying blood coagulation. Five subtasks (threshold, triggering, control by blood flow velocity, spatial propagation, and localization), together with responsible modules, can be identified for the coagulation network. We show that the task of coagulation triggering is completely regulated by a two-step pathway containing a single positive feedback of factor V activation by thrombin. These theoretical predictions are experimentally confirmed by studies of fibrin generation in normal, factor V-, and factor VIII-deficient plasmas. The function of the factor V-dependent feedback is to minimize temporal and parametrical intervals of fibrin clot instability. We speculate that this pathway serves to lessen possibility of fibrin clot disruption by flow and subsequent thromboembolism. PMID:20441738

  2. Interplay between coagulation and vascular inflammation in sickle cell disease

    PubMed Central

    Sparkenbaugh, Erica; Pawlinski, Rafal

    2013-01-01

    Sickle cell disease is the most common inherited hematologic disorder that leads to the irreversible damage of multiple organs. Although sickling of red blood cells and vaso-occlusion are central to the pathophysiology of sickle cell disease the importance of hemolytic anemia and vasculopathy has been recently recognized. Hypercoagulation state is another prominent feature of sickle cell disease and is mediated by activation of both intrinsic and extrinsic coagulation pathways. Growing evidence demonstrates that coagulation may not only contribute to the thrombotic complications, but also to vascular inflammation associated with this disease. This article summarizes the role of vascular inflammation and coagulation activation, discusses potential mechanisms responsible for activation of coagulation and reviews recent data demonstrating the crosstalk between coagulation and vascular inflammation in sickle cell disease. PMID:23593937

  3. Hepatocyte tissue factor activates the coagulation cascade in mice

    PubMed Central

    Sullivan, Bradley P.; Kopec, Anna K.; Joshi, Nikita; Cline, Holly; Brown, Juliette A.; Bishop, Stephanie C.; Kassel, Karen M.; Rockwell, Cheryl; Mackman, Nigel

    2013-01-01

    In this study, we characterized tissue factor (TF) expression in mouse hepatocytes (HPCs) and evaluated its role in mouse models of HPC transplantation and acetaminophen (APAP) overdose. TF expression was significantly reduced in isolated HPCs and liver homogenates from TFflox/flox/albumin-Cre mice (HPC?TF mice) compared with TFflox/flox mice (control mice). Isolated mouse HPCs expressed low levels of TF that clotted factor VII-deficient human plasma. In addition, HPC TF initiated factor Xa generation without exogenous factor VIIa, and TF activity was increased dramatically after cell lysis. Treatment of HPCs with an inhibitory TF antibody or a cell-impermeable lysine-conjugating reagent prior to lysis substantially reduced TF activity, suggesting that TF was mainly present on the cell surface. Thrombin generation was dramatically reduced in APAP-treated HPC?TF mice compared with APAP-treated control mice. In addition, thrombin generation was dependent on donor HPC TF expression in a model of HPC transplantation. These results suggest that mouse HPCs constitutively express cell surface TF that mediates activation of coagulation during hepatocellular injury. PMID:23305736

  4. Comparison of mean normal prothrombin time (PT) with PT of fresh normal pooled plasma or of a lyophilized control plasma (R82A) as denominator to express PT results: collaborative study of the International Federation of Clinical Chemistry. IFCC Working Group Standardization of Coagulation Tests.

    PubMed

    D'Angelo, A; Galli, L; Lang, H

    1997-11-01

    The mean normal prothrombin time (MNPT) is currently recommended as the denominator term in the expression of PT ratio or International Normalized Ratio (INR) values. The PT of lyophilized normal control plasmas might also be used in calculating PT ratios, but the overall accuracy of this approach and its dependence on reagents and endpoint detectors have not been evaluated in detail. In an IFCC collaborative study involving 15 expert laboratories and 58 PT systems, the PT ratios of 30 apparently healthy subjects were expressed with the use of the MNPT, the PT of fresh normal pooled plasma (FNPP) obtained from the same apparently healthy subjects, or the PT of plasma R82A--a lyophilized normal pooled plasma prepared by the Verband der Deutschen Geräte-Hersteller for in-house calibration of a large amount of control plasma--as the denominator term. The total imprecision of the PT of plasma R82A averaged 2.16%. Mean PT ratios did not differ from 1.00 (mean 1.00, range 1.00-1.01) with the use of the MNPT as the denominator term. Mean PT ratios were > 1.00 with the FNPP-PT as the denominator term (1.02, 0.96-1.05), and differed according to endpoint detectors (P = 0.024). Mean PT ratios with plasma R82A-PT as the denominator term averaged 0.98 (range 0.91-1.06) with plain thromboplastins (n = 11), 1.02 (0.98-1.06) with combined thromboplastins (n = 3), and 0.93 (0.87-0.97) with recombinant thromboplastins (n = 2), but they differed according to the brand of plain or recombinant reagents (P = 0.00001), the endpoint detector (P < 0.0025), and the plasma citrate concentration (P < 0.0025). These findings underline the differences in the PT of lyophilized plasma R82A and the MNPT and PT of FNPP obtained from the same individuals and support the recommendation that the system-specific MNPT should be used as the ideal index of the normal PT in the calculation of INR values. PMID:9365404

  5. Evaluation and performance characteristics of the Q Hemostasis Analyzer, an automated coagulation analyzer.

    PubMed

    Toulon, Pierre; Fischer, Florence; Appert-Flory, Anny; Jambou, Didier

    2014-05-01

    The Q Hemostasis Analyzer (Grifols, Barcelona, Spain) is a fully-automated random-access multiparameter analyzer, designed to perform coagulation, chromogenic and immunologic assays. It is equipped with a cap-piercing system. The instrument was evaluated in a hemostasis laboratory of a University Hospital with respect to its technical features in the determination of coagulation i.e. prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time, fibrinogen and single coagulation factors V (FV) and VIII (FVIII), chromogenic [antithrombin (AT) and protein C activity] and immunologic assays [von Willebrand factor antigen (vWF:Ag) concentration], using reagents from the analyzer manufacturer. Total precision (evaluated as the coefficient of variation) was below 6% for most parameters both in normal and in pathological ranges, except for FV, FVIII, AT and vWF:Ag both in the normal and pathological samples. No carryover was detected in alternating aPTT measurement in a pool of normal plasma samples and in the same pool spiked with unfractionated heparin (>1.5 IU/mL). The effective throughput was 154 PT, 66 PT/aPTT, 42 PT/aPTT/fibrinogen, and 38 PT/aPTT/AT per hour, leading to 154 to 114 tests performed per hour, depending of the tested panel. Test results obtained on the Q Hemostasis Analyzer were well correlated with those obtained on the ACL TOP analyzer (Instrumentation Laboratory), with r between 0.862 and 0.989. In conclusion, routine coagulation testing can be performed on the Q Hemostasis Analyzer with satisfactory precision and the same apply to more specialized and specific tests. PMID:24650798

  6. [A case of disseminated intravascular coagulation--a paraneoplastic manifestation of a borderline ovarian tumor].

    PubMed

    B?l?nescu, I; Coli??, D; Moicean, A; Du?u, R; St?nculescu, M; Voinea, S

    1998-01-01

    A 24-year-old-woman was admitted because of disseminated intravascular coagulation (DIC), menometrorrhagia and galactorrhea. The investigations performed showed a right adnexal tumor after the equilibration of DIC with plasma substitution, we performed a right adnexectomy with limited excision of peritoneal. The pathologic examination showed a focus of endometriosis on the right ovary who had a polycystic look and a right adnexal fibromyxoma (premalignant lesion). The post operative evolution was good, with the loss of entire onco-hemato-endocrinologic picture. We describe the interrelation between DIC (paraneoplastic syndrome), menometrorrhagia and galactorrhea, the pathologic hypothesis and the treatment of DIC. PMID:9854871

  7. Biological Effects of Targeted Gene Inactivation and Gene Transfer of the Coagulation and Fibrinolytic Systems in Mice

    Microsoft Academic Search

    Peter Carmeliet; Désiré Collen

    Preservation of vascular integrity following traumatic or infectious challenges is essential for the survival of multicellular\\u000a organisms. A major defense mechanism involves the formation of hemostatic plugs by activation of platelets and polymerization\\u000a of fibrin. Initiation of the plasma coagulation system on exposure of blood to nonvascular cells is triggered by tissue factor\\u000a (TF), which is expressed by a variety

  8. A DSMC Study of Low Pressure Argon Discharge

    NASA Astrophysics Data System (ADS)

    Hash, David; Meyyappan, M.

    1997-10-01

    Work toward a self-consistent plasma simulation using the DSMC method for examination of the flowfields of low-pressure high density plasma reactors is presented. Presently, DSMC simulations for these applications involve either treating the electrons as a fluid or imposing experimentally determined values for the electron number density profile. In either approach, the electrons themselves are not physically simulated. Self-consistent plasma DSMC simulations have been conducted for aerospace applications but at a severe computational cost due in part to the scalar architectures on which the codes were employed. The present work attempts to conduct such simulations at a more reasonable cost using a plasma version of the object-oriented parallel Cornell DSMC code, MONACO, on an IBM SP-2. Due the availability of experimental data, the GEC reference cell is chosen to conduct preliminary investigations. An argon discharge is examined thus affording a simple chemistry set with eight gas-phase reactions and five species: Ar, Ar^+, Ar^*, Ar_2, and e where Ar^* is a metastable.

  9. Measurements of electron densities and temperatures in low-pressure arcjet plasmas operating under diamond growth conditions

    Microsoft Academic Search

    K. R. Stalder; E. A. Brinkman; J. B. Jeffries

    1996-01-01

    Summary form only given. We have measured the spatial variation of plasma parameters in a low-pressure DC arcjet plasma used in the deposition of diamond thin films. A Langmuir probe was inserted into the plasma jet from the side. Various gas mixtures were studied, including pure argon, argon-hydrogen mixtures, and argon-hydrogen-methane mixtures, with and without NO seeded into the gas

  10. Long-Term Expression of Human Coagulation Factor VIII and Correction of Hemophilia A after in vivo Retroviral Gene Transfer in Factor VIII-Deficient Mice

    Microsoft Academic Search

    Thierry Vandendriessche; Veerle Vanslembrouck; Inge Goovaerts; Hans Zwinnen; Marie-Line Vanderhaeghen; Desire Collen; Marinee K. L. Chuah

    1999-01-01

    Hemophilia A is caused by a deficiency in coagulation factor VIII (FVIII) and predisposes to spontaneous bleeding that can be life-threatening or lead to chronic disabilities. It is well suited for gene therapy because a moderate increase in plasma FVIII concentration has therapeutic effects. Improved retroviral vectors expressing high levels of human FVIII were pseudotyped with the vesicular stomatitis virus

  11. New Measurement of ^39Ar in Underground Argon with a Low Background Liquid Argon Detector

    NASA Astrophysics Data System (ADS)

    Xu, Jingke

    2012-03-01

    A low background liquid argon detector has been developed for sensitive measurements of the beta radioactive ^39Ar in argon from underground sources. The measurement is motivated by the need to improve on earlier studies that showed no sign of ^39Ar in certain sources of underground argon, but with a limited sensitivity of ˜ 5% relative to ^39Ar in atmospheric argon[1]. We will report preliminary measurements taken with the low background detector that was commissioned and operated at the Kimballton Underground Research Facility (KURF) in Virginia. A combination of passive and active background reduction techniques resulted in a very low background and a null result with sensitivity to ^39Ar less than 1% of atmospheric. The results confirm that underground argon is well suited for direct detection of dark matter WIMPs. [4pt] [1] D. Acosta-Kane et al., Nucl. Instr. Meth. A 587:46 (2008)

  12. Relationship between Circulating Tumor Cells, Blood Coagulation, and Urokinase-Plasminogen-Activator System in Early Breast Cancer Patients.

    PubMed

    Mego, Michal; Karaba, Marian; Minarik, Gabriel; Benca, Juraj; Sedlácková, Tatiana; Tothova, Lubomira; Vlkova, Barbora; Cierna, Zuzana; Janega, Pavol; Luha, Jan; Gronesova, Paulina; Pindak, Daniel; Fridrichova, Ivana; Celec, Peter; Reuben, James M; Cristofanilli, Massimo; Mardiak, Jozef

    2015-03-01

    Cancer is a risk factor for venous thromboembolism (VTE) and plasma d-dimer (DD) and tissue factor (TF) are established VTE associated markers. Circulating tumor cells (CTCs) are associated with the risk of VTE in metastatic breast cancer. This study aimed to correlate CTCs, blood coagulation and the urokinase plasminogen activator (uPA) system in primary breast cancer (PBC) patients. This prospective study included 116 PBC patients treated by primary surgery. CTCs were detected by quantitative RT-PCR assay for expression of epithelial (CK19) or epithelial-mesenchymal transition (EMT) genes (TWIST1, SNAIL1, SLUG, ZEB1, FOXC2). Plasma DD, TF, uPA system proteins were detected by enzyme-linked immunosorbent assays, while expressions of uPA system in surgical specimens were evaluated by immunohistochemistry. CTCs were detected in 27.6% patients. Patients with CTCs had a significantly higher mean plasma DD (ng/mL) than those of patients without CTCs (632.4 versus 365.4, p = 0.000004). There was no association between plasma TF and CTCs. Epithelial CTCs exhibit higher expression of uPA system genes compared to EMT_CTCs. Patients with CTCs had higher plasma uPA proteins than those of patients without CTCs; there was no correlation between tissue expression of uPA system, CTCs, DD or TF levels. In multivariate analysis CTCs and patients age were independent factors associated with plasma DD. We found association between plasma DD and CTCs indicating a potential role for activation of the coagulation cascade in the early metastatic process. CTCs could be directly involved in coagulation activation or increased CTCs could be marker of aggressive disease and increased VTE risk. PMID:25623304

  13. Benign intracranial hypertension associated to blood coagulation derangements

    PubMed Central

    De Lucia, Domenico; Napolitano, Marisanta; Di Micco, Pierpaolo; Niglio, Alferio; Fontanella, Andrea; Di lorio, Giuseppe

    2006-01-01

    Background Benign Intracranial Hypertension (BIH) may be caused, at least in part, by intracranial sinus thrombosis. Thrombosis is normally due to derangements in blood coagulation cascade which may predispose to abnormal clotting activation or deficiency in natural inhibitors' control. The aim of the study is to examine the strength of the association between risk factors for thrombosis and BIH. Patients and methods The incidence of prothrombotic abnormalities among a randomly investigated cohort of 17 patients with BIH, was compared with 51 healthy subjects matched for sex, age, body mass index, height and social background. Results The number of subjects with protein C deficiency was significantly higher in patients than in controls (3 vs 1, p < .001; Fisher Exact Test). Moderate to high titers of anticardiolipin antibodies (?2-Glycoprotein type I) were found in 8 out of 17 patients. Increased plasma levels of prothrombin fragment 1+2, fibrinopeptide A (FPA), and PAI-1 were demonstrated in patients group (5.7 ± 1.15 nM vs 0.45 ± 0.35 nM; 8.7 ± 2.5 ng/mL vs 2.2 ± 1.25 ng/mL; 45.7 ± 12.5 ng/mL vs 8.5 ± 6.7 ng/mL, respectively; p < .001; Fisher Exact Test). Gene polymorphisms for factor V Leiden mutation, prothrombin mutation 20210 A/G, MTHFR 677 C/T, PAI-1 4G/5G, ACE I/D were detected in 13 patients. Discussion In agreement with other authors our data suggest a state of hypercoagulability in BIH associated with gene polymorphisms. Our findings also showed that mutations in cardiovascular genes significantly discriminate subjects with a BIH history. The association between coagulation and gene derangements, usually regarded to as cryptogenic, may suggest a possible pathogenetic mechanism in BIH. So, a prothrombotic tendency may exist that would, at least in part, explain some cases of BIH. Although based on a small population, these findings raise the exciting possibility of using these haemostatic factors as markers for selecting high-risk subjects in BIH disease. PMID:17187688

  14. The procoagulant and proinflammatory plasma contact system

    Microsoft Academic Search

    Thomas Renné

    The contact system is a plasma protease cascade that is initiated by coagulation factor XII activation on cardiovascular cells.\\u000a The system starts procoagulant and proinflammatory reactions, via the intrinsic pathway of coagulation or the kallikrein–kinin\\u000a system, respectively. The biochemistry of the contact system in vitro is well understood, however, its in vivo functions are\\u000a just beginning to emerge. Data obtained

  15. Light guide applicators for photon coagulators

    NASA Astrophysics Data System (ADS)

    Stepien, Ryszard; Kociszewski, Longin; Pysz, Dariusz

    1997-12-01

    Results of the R+D works as well as technological trials aiming at conception and manufacturing of the light guide rods (applicators) for photon coagulators, applied for therapeutical treatment and surgery, have been presented. Such rods, due to their light guiding structure, enable effective guidance of the NIR radiation of a high energy directly to the treatment area. A method was worked out to convert specially matched glasses into the integrated light transmitting structures. The effect of a type and quality of the glass, light guides structure and their aperture onto the effectiveness of radiation power transmission was investigated. The first trials were carried out to apply new type of rods for laparoscope and gynecological treatments.

  16. Light guide applicators for photon coagulators

    NASA Astrophysics Data System (ADS)

    Stepien, Ryszard; Kociszewski, Longin; Pysz, Dariusz

    1998-01-01

    Results of the R+D works as well as technological trials aiming at conception and manufacturing of the light guide rods (applicators) for photon coagulators, applied for therapeutical treatment and surgery, have been presented. Such rods, due to their light guiding structure, enable effective guidance of the NIR radiation of a high energy directly to the treatment area. A method was worked out to convert specially matched glasses into the integrated light transmitting structures. The effect of a type and quality of the glass, light guides structure and their aperture onto the effectiveness of radiation power transmission was investigated. The first trials were carried out to apply new type of rods for laparoscope and gynecological treatments.

  17. Dapsone hypersensitivity syndrome causing disseminated intravascular coagulation

    PubMed Central

    Figtree, Melanie Clare; Miyakis, Spiros; Tanaka, Kumiko; Martin, Linda; Konecny, Pam; Krilis, Steven

    2009-01-01

    Dapsone hypersensitivity syndrome is an idiosyncratic reaction to this drug and can present with different clinical manifestations of varying severity. We describe a patient with disseminated intravascular coagulation (DIC) as an adverse reaction to dapsone. To the best of our knowledge, this is the first time it has been described in the literature. She presented with fever, rash and abdominal pain; she also had marked eosinophilia and features suggestive of oxidative haemolysis. Her course was complicated by DIC, splenic infarction and gastrointestinal bleeding. Extensive investigations did not reveal any alternative aetiology. She was initially treated with supportive measures and folic acid; steroids were administered later, following clinical deterioration. There was gradual improvement and the steroids were tapered. The patient recovered fully and remains well; her underlying chronic dermatologic condition is under satisfactory control with other medications. PMID:21829418

  18. Optimized alumina coagulants for water treatment

    DOEpatents

    Nyman, May D. (Albuquerque, NM); Stewart, Thomas A. (Albuquerque, NM)

    2012-02-21

    Substitution of a single Ga-atom or single Ge-atom (GaAl.sub.12 and GeAl.sub.12 respectively) into the center of an aluminum Keggin polycation (Al.sub.13) produces an optimal water-treatment product for neutralization and coagulation of anionic contaminants in water. GaAl.sub.12 consistently shows .about.1 order of magnitude increase in pathogen reduction, compared to Al.sub.13. At a concentration of 2 ppm, GaAl.sub.12 performs equivalently to 40 ppm alum, removing .about.90% of the dissolved organic material. The substituted GaAl.sub.12 product also offers extended shelf-life and consistent performance. We also synthesized a related polyaluminum chloride compound made of pre-hydrolyzed dissolved alumina clusters of [GaO.sub.4Al.sub.12(OH).sub.24(H.sub.2O).sub.12].sup.7+.

  19. Percutaneous laser balloon coagulation of accessory pathways

    NASA Astrophysics Data System (ADS)

    McMath, Linda P.; Schuger, Claudio D.; Crilley, Richard J.; Spears, J. Richard

    1991-05-01

    Nonsurgical ablation techniques have been proposed to cease conduction through accessory pathways which electrically connect the atrium and ventricle. The intent of this research was to investigate further the potential use of laser energy, delivered via a balloon catheter in the canine coronary sinus to photocoagulate the myocardial fibers responsible for accessory pathway conduction. Based on histological evaluation of the lesions created in acute and chronic studies, the extent of coagulation necrosis is sufficient to ablate most pathways which lie adjacent to the coronary sinus. Results from surface temperature measurements using repetitive laser exposures suggest that optical and/or thermal changes occurring in the myocardium are of greater importance than those occurring in the adipose tissue. Since the laser balloon catheter is surrounded by various tissue types, a Monte Carlo model was developed to determine the distribution of light in the atrioventricular groove.

  20. Effect of rivaroxaban on blood coagulation using the viscoelastic coagulation test ROTEM™.

    PubMed

    Casutt, M; Konrad, C; Schuepfer, G

    2012-11-01

    This study investigated the influence of the oral direct inhibitor of factor Xa rivaroxaban on blood coagulation measured by rotation thrombelastometry ROTEM™. Blood was obtained from 11 healthy male volunteers before and 2.5 h after oral administration of 10 mg rivaroxaban. In addition to standard coagulation tests clot formation was measured by ROTEM™ analyzing extrinsic (Extem) and intrinsic thrombelastometry (Intem). Significant differences to the baseline values were found in the Extem clotting time (Extem-CT, 58?±?9 s and 87?±?17 s, p?coagulation by rivaroxaban. PMID:23053307