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1

Coagulation of Dust Particles in Argon Plasma of RF Discharge  

SciTech Connect

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.

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

2

Argon plasma coagulation therapy for hemorrhagic radiation proctosigmoiditis  

Microsoft Academic Search

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:

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

1999-01-01

3

Endobronchial argon plasma coagulation for treatment of dieulafoy disease.  

PubMed

Dieulafoy disease of the bronchus is a rare condition. A 28-y-old male patient with recurrent exacerbations of hemoptysis (producing up to 300 mL) over the previous 4 y was admitted to our hospital following an acute episode. A 3-mm sessile lesion covered with somewhat ulcerated smooth mucosa was detected at the distal end of the left main bronchus, at the entrance to the upper lobe bronchus. Bleeding was controlled by argon plasma coagulation, and total coagulation of the lesion was also therapeutic. The patient has been followed for 2 y with no further bleeding. In the very few reported cases of Dieulafoy disease, surgical resection and selective embolization were the treatments used. Endobronchial treatment has not been described before as a therapeutic approach. We emphasize that argon plasma coagulation can be a treatment option in such cases. PMID:25161300

Dalar, Levent; Sökücü, Sinem N; Özdemir, Cengiz; Büyükkale, Songül; Alt?n, Sedat

2015-01-01

4

Trimming a Metallic Biliary Stent Using an Argon Plasma Coagulator  

SciTech Connect

Background. Distal migration is one of the common complications after insertion of a covered metallic stent. Stent repositioning or removal is not always possible in every patient. Therefore, trimming using an argon plasma coagulator (APC) may be a good alternative method to solve this problem. Methods. Metallic stent trimming by APC was performed in 2 patients with biliary Wallstent migration and in another patient with esophageal Ultraflex stent migration. The power setting was 60-100 watts with an argon flow of 0.8 l/min. Observations. The procedure was successfully performed and all distal parts of the stents were removed. No significant collateral damage to the nearby mucosa was observed. Conclusions. In a patient with a distally migrated metallic stent, trimming of the stent is possible by means of an APC. This new method may be applicable to other sites of metallic stent migration.

Rerknimitr, Rungsun, E-mail: Rungsun@pol.net; Naprasert, Pisit; Kongkam, Pradermchai; Kullavanijaya, Pinit [Faculty of Medicine, Chulalongkorn University, Gastroenterology Unit, Department of Internal Medicine (Thailand)

2007-06-15

5

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

Microsoft Academic Search

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

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

1999-01-01

6

Argon Plasma Coagulation for the Treatment of Hemorrhagic Radiation Colitis  

PubMed Central

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

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

2012-01-01

7

Argon plasma coagulation for the treatment of hemorrhagic radiation colitis.  

PubMed

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

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

2012-05-01

8

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

PubMed Central

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

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

2014-01-01

9

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

Microsoft Academic Search

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

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

1998-01-01

10

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

Microsoft Academic Search

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

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

1998-01-01

11

[Argon plasma coagulation in endoscopic therapy of CREST syndrome associated upper gastrointestinal hemorrhage].  

PubMed

We report on the case of a 55-year-old patient suffering from progressive systemic sclerosis (PSS). The patient was sent to our department when clinical symptoms of an acute upper gastrointestinal hemorrhage occurred. Upper endoscopy showed a watermelon stomach and fresh blood in the stomach. The presence of teleangiectasias in the antrum could be proved histologically. Since the teleangiectasias found in the antrum were the only possible source of the hemorrhage three sessions of endoscopic argon plasma coagulation were performed. Macroscopically, a nearly complete disappearance of teleangiectasias could be achieved. After a follow-up of six months, there have been no clinical signs of another hemorrhage episode. This case shows that the existence of gastrointestinal teleangiectasias should be considered when chronic anemia or acute gastrointestinal hemorrhage occur in patients with PSS. Further it is demonstrated that even extended gastrointestinal teleangiectasias can be successfully treated by endoscopically performed argon plasma coagulation. PMID:9281240

Klump, B; Schneider, G A; Fierlbeck, G; Hoeft, S; Gregor, M; Porschen, R

1997-06-01

12

Endoscopic removal of a migrating polyester band using argon plasma coagulation.  

PubMed

A case is reported of a 40-year-old woman with a past history of bariatric surgery with vertical banding gastroplasty. Migrating band was observed during upper GI endoscopy performed for pyrosis. Before undergoing another bariatric intervention, migrated band had to be removed. This procedure was successfully performed endoscopically using argon plasma coagulation. No complication occurred. This case highlights that migrated band could be easily and safely removed without the need of specific or dedicated endoscopic tool. PMID:23273494

Musquer, Nicolas; Letessier, Eric; Le Rhun, Marc; Coron, Emmanuel

2013-06-01

13

Argon plasma coagulation in the management of uncovered tracheal stent fracture  

PubMed Central

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.

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

2014-01-01

14

Epinephrine plus argon plasma or heater probe coagulation in ulcer bleeding  

PubMed Central

AIM: To compare the effectiveness of argon plasma coagulation (APC) and heater probe coagulation (HPC) in non-variceal upper gastrointestinal bleeding. METHODS: Eighty-five (18 female, 67 male) patients admitted for acute gastrointestinal bleeding due to gastric or duodenal ulcer were included in the study. Upper endoscopy was performed and HPC or APC were chosen randomly to stop the bleeding. Initial hemostasis and rebleeding rates were primary and secondary end-points of the study. RESULTS: Initial hemostasis was achieved in 97.7% (42/43) and 81% (36/42) of the APC and HPC groups, respectively (P < 0.05). Rebleeding rates were 2.4% (1/42) and 8.3% (3/36) in the APC and HPC groups, respectively, at 4 wk (P > 0.05). CONCLUSION: APC is an effective hemostatic method in bleeding peptic ulcers. Larger multicenter trials are necessary to confirm these results. PMID:22039325

Karaman, Ahmet; Baskol, Mevlut; Gursoy, Sebnem; Torun, Edip; Yurci, Alper; Ozel, Banu Demet; Guven, Kadri; Ozbakir, Omer; Yucesoy, Mehmet

2011-01-01

15

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

Microsoft Academic Search

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

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

2002-01-01

16

Effective treatment of solitary rectal ulcer syndrome using argon plasma coagulation  

PubMed Central

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

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

2014-01-01

17

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

Microsoft Academic Search

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

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

1998-01-01

18

Preserving the Integrity of Oesophageal Stents with Laser Therapy and Argon Plasma Coagulation: An In Vitro Study  

Microsoft Academic Search

. Thermal lasers and argon plasma coagulation are widely used in the treatment of stent overgrowth in patients with advanced\\u000a oesophageal malignancy. The aim of treatment is to achieve patency while avoiding damage to the prosthesis. This experimental\\u000a study was designed to determine the power and duration of application that can be safely tolerated by four different types\\u000a of oesophageal

N. Rajendran; N. Krasner

2000-01-01

19

Argon plasma coagulation for superficial esophageal squamous-cell carcinoma in high-risk patients  

PubMed Central

AIM: To evaluate the usefulness and safety of argon plasma coagulation (APC) for superficial esophageal squamous-cell carcinoma (SESC) in high-risk patients. METHODS: We studied 17 patients (15 men and 2 women, 21 lesions) with SESC in whom endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), and open surgery were contraindicated from March 1999 through February 2009. None of the patients could tolerate prolonged EMR/ESD or open surgery because of severe concomitant disease (e.g., liver cirrhosis, cerebral infarction, or ischemic heart disease) or scar formation after EMR/ESD and chemoradiotherapy. After conventional endoscopy, an iodine stain was sprayed on the esophageal mucosa to determine the lesion margins. The lesion was then ablated by APC. We retrospectively studied the treatment time, number of APC sessions per site, complications, presence or absence of recurrence, and time to recurrence. RESULTS: The median duration of follow-up was 36 mo (range: 6-120 mo). All of the tumors were macroscopically classified as superficial and slightly depressed type (0-IIc). The preoperative depth of invasion was clinical T1a (mucosal cancer) for 19 lesions and clinical T1b (submucosal cancer) for 2. The median treatment time was 15 min (range: 10-36 min). The median number of treatment sessions per site was 2 (range: 1-4). The median hospital stay was 14 d (range: 5-68 d). Among the 17 patients (21 lesions), 2 (9.5%) had recurrence and underwent additional APC with no subsequent evidence of recurrence. There were no treatment-related complications, such as bleeding or perforation. CONCLUSION: APC is considered to be safe and effective for the management of SESC that cannot be resected endoscopically because of underlying disease, as well as for the control of recurrence after EMR and local recurrence after chemoradiotherapy. PMID:23082058

Tahara, Kumiko; Tanabe, Satoshi; Ishido, Kenji; Higuchi, Katsuhiko; Sasaki, Tohru; Katada, Chikatoshi; Azuma, Mizutomo; Nakatani, Kento; Naruke, Akira; Kim, Myungchul; Koizumi, Wasaburo

2012-01-01

20

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

SciTech Connect

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.

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

21

Comparison of argon plasma coagulation in management of upper gastrointestinal angiodysplasia and gastric antral vascular ectasia hemorrhage  

PubMed Central

Background Vascular ectasias, including gastric antral vascular ectasia (GAVE) and angiodysplasia, are increasingly recognized as important sources of gastrointestinal bleeding. This study investigated and compared the efficacies and outcomes of treatment of upper gastrointestinal (UGI) angiodysplasia and GAVE hemorrhage by endoscopic argon plasma coagulation (APC). Methods From January 2006 to December 2009, 46 patients diagnosed with upper GI bleeding caused by angiodysplasia or GAVE at a tertiary hospital were recruited into this study. They included 26 males and 20 females with an average age of 65.6?years (range, 45–90?years). All patients underwent APC for hemostasis during an endoscopic procedure. Parameters such as underlying co-morbidities, number of endoscopic treatment sessions, recurrent bleeding, and clinical outcomes during follow-up were analyzed. Results The 46 patients with UGI vascular ectasia hemorrhage included 27 patients with angiodysplasia and 19 with GAVE. The patients with angiodysplasia were older than those with GAVE (71.6?±?10.2?years versus 61.8?±?11.9?years, P?=?0.005). More GAVE patients than angiodysplasia patients had co-existing liver cirrhosis (63.2% versus 25.9%, P?=?0.012). The patients with GAVE had a higher rate of recurrent bleeding (78.9% versus 7.4%, P?

2012-01-01

22

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

PubMed Central

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

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

2014-01-01

23

Argon beam coagulation in the management of placenta accreta  

Microsoft Academic Search

Background: Placenta accreta has been estimated to complicate approximately one in 2500 deliveries, resulting in significant morbidity and mortality. Conservative treatment of placenta accreta has been done in certain clinical situations when preservation of the uterus and further childbearing are desired. The Argon beam coagulator is an electrosurgical device used for hemostasis during various operations. We report its use in

Stephen E Scarantino; James G Reilly; Michael L Moretti; Vincent T Pillari

1999-01-01

24

Laparoscopic Presacral Neurectomy Versus Neurotomy with the Argon Beam Coagulator  

PubMed

Presacral neurectomy is effective treatment for dysmenorrhea and midline pelvic pain. The purpose of this paper is to report the benefits of the argon beam coagulator (ABC) used laparoscopically to perform a presacral neurotomy compared with conventional techniques for presacral neurectomy. In 51 patients undergoing laparoscopic presacral neurectomy, 34 were performed using the ABC only without dissection or excision, and 17 underwent presacral neurectomy by conventional methods. Postoperative pain reduction was the same in both groups, 77% versus 73%, with average anesthesia time 64 minutes for the ABC neurotomy versus 92 minutes with conventional techniques. One major vascular complication requiring immediate laparotomy occurred in the ABC group. When properly applied laparoscopically, the ABC is an effective tool to rapidly coagulate and separate the presacral nerves with minimal smoke, excellent visualization and no retroperitoneal dissection. PMID:9073717

McTavish; Daniell; Lalonde

1994-08-01

25

Probe measurements in argon plasma jets operated in ambient argon  

Microsoft Academic Search

Measurements of local enthalpies and velocities have been performed in plasma jets generated by a DC plasma spray torch, using an enthalpy probe. The torch has been operated in an argon confined atmosphere at different currents and argon flow rates.(1) The validity of the measured enthalpy and velocity profiles has been checked by performing energy flux and mass flux balances,

A. Capetti; E. Pfender

1989-01-01

26

Electrical and spectroscopic characterization of a surgical argon plasma discharge  

NASA Astrophysics Data System (ADS)

For electrosurgical procedures, the argon plasma coagulation (APC) discharge is a well-established atmospheric-pressure plasma tool for thermal haemostasis and devitalization of biological tissue. To characterize this plasma source, voltage-current measurements, microphotography, optical emission spectroscopy and numerical simulation are applied. Two discharge modes are established during the operation of the APC plasma source. A short transient spark discharge is ignited within the positive half period of the applied high voltage after a streamer channel connects the APC probe and the counter-electrode. During the second phase, which continues under negative high voltage, a glow discharge is stabilized in the plasma channel.

Keller, Sandra; Bibinov, Nikita; Neugebauer, Alexander; Awakowicz, Peter

2013-01-01

27

Transport coefficients of argon, nitrogen, oxygen, argon-nitrogen, and argon-oxygen plasmas  

Microsoft Academic Search

Calculated values of the viscosity, thermal conductivity, and electrical conductivity of argon, nitrogen, and oxygen plasmas, and mixtures of argon anti nitrogen and of argon anti oxygen, are presented. In addition, combined ordinary, pressure, and thermal diffusion coefficients are given for the gas mixtures. These three combined diffusion coefficients fully describe di fusion of the two gases, irrespective of their

A. B. Murphy; C. J. Arundelli

1994-01-01

28

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

Microsoft Academic Search

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.

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

29

Diamond film growth argon-carbon plasmas  

DOEpatents

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.

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

30

Nanoparticle-Plasma Interactions in Dusty Argon-Hydrogen Plasmas  

NASA Astrophysics Data System (ADS)

We studied the role of hydrogen in altering the plasma-nanoparticle interactions in low pressure dusty Ar-H2 plasma. Most dusty plasmas in which particles form through chemical nucleation, are multi-component plasmas containing hydrogen. As hydrogen's ionization potential is close to that of argon, both gases may be ionized. The presence of the light mass hydrogen ions has the potential to modify the plasma and plasma-nanoparticle interactions. We developed a global model for dusty argon-hydrogen plasma. For given absorbed power, nanoparticle density, pressure, and chamber size, we solved the power balance, plasma species balance, and particle current balance equations. We included a system of rate equations for important argon-hydrogen plasma chemical reactions and obtained electron energy distribution function (EEDF) using ZDPlasKin. A trace amount of H2 gas in Ar discharge causes Ar^+, ArH^+, and H3^+ to be the dominant ions. Their relative densities are dependent on chamber pressure, gas composition, and the nanoparticle density. Increase in H2 gas fraction reduces the plasma density. The presence of light ions reduces the average particle charge. Electron collisions with hydrogen and with the nanoparticles affect the EEDF shape. Overall, we find that the presence of H2 in the discharge significantly alters the plasma properties and the fundamental plasma-nanoparticle interactions. This work was supported by the US Dept. of Energy Plasma Science Center and DOE grant DE/SC-0002391.

Kortshagen, Uwe; Mamunuru, Meenakshi

2012-10-01

31

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

SciTech Connect

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.

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

2010-07-15

32

The interaction of an atmospheric pressure plasma jet using argon or argon plus hydrogen peroxide vapour addition with bacillus subtilis  

Microsoft Academic Search

This paper reports that an atmospheric pressure dielectric barrier discharge plasma jet, which uses argon or argon + hydrogen peroxide vapour as the working gas, is designed to sterilize the bacillus subtilis. Compared with the pure argon plasma, the bacterial inactivation efficacy has a significant improvement when hydrogen peroxide vapour is added into the plasma jet. In order to determine

San-Xi Deng; Cheng Cheng; Guo-Hua Ni; Yue-Dong Meng; Hua Chen

2010-01-01

33

Blood plasma coagulation studied by surface plasmon resonance  

NASA Astrophysics Data System (ADS)

A surface plasmon resonance (SPR) apparatus was used to investigate blood plasma coagulation in real time as a function of thromboplastin and heparin concentrations. The response curves were analyzed by curve fitting to a sigmoid curve equation, followed by extraction of the time constant. Clotting activation by thromboplastin resulted in increased time constant, as compared to spontaneously clotted plasma, in a dose dependent way. Addition of heparin to the thromboplastin-activated plasma counteracted this effect. Atomic force microscopy (AFM) pictures of sensor surfaces dried after completed clotting, revealed differences in fibrin network structures as a function of thromboplastin concentration, and the fiber thickness increased with decreased thromboplastin concentration. The physical reason for the SPR signal observed is ambiguous and is therefore discussed. However, the results summarized in the plots and the fibrin network properties observed by AFM correlate well with present common methods used to analyze blood coagulation.

Vikinge, Trine P.; Hansson, Kenny M.; Benesch, Johan; Johansen, Knut; Ranby, Mats; Lindahl, Tomas L.; Liedberg, Bo; Lundstoem, Ingemar; Tengvall, Pentti

2000-01-01

34

Nonequilibrium effects of diluent addition in a recombining argon plasma  

NASA Astrophysics Data System (ADS)

Spectroscopic and calorimetric measurements have been made using a 50 kW radio frequency inductively coupled plasma torch operated at atmospheric pressure with maximum temperatures and electron densities near 8500 K and 3×1021 m-3, respectively. The plasma flowed through a water-cooled quartz test section which enabled the study of nonequilibrium effects on both a recombining pure argon plasma and a recombining argon plasma with hydrogen, nitrogen, or neon. The pure argon plasma is found to be well described by a partial equilibrium model in which the free and bound-excited electrons are in mutual equilibrium irrespective of possible departures from equilibrium with the ground state. The addition of just tenths of a percent of either atomic hydrogen or nitrogen (but not neon, in contrast) is found to significantly affect the plasma's state of equilibrium for electron densities roughly less than 1021 m-3 because of a nearly gas-kinetic reaction between argon's first excited state and the diluent's ground state. This ``quenching'' reaction provides a depopulating mechanism for argon's first excited state and thereby inhibits the establishment of partial equilibrium which then invalidates several common diagnostic methods. The extent of quenching depends on the particular diluent, the amount of diluent relative to the electron number density, and on the temperature. These experimental observations are supported by an appropriately modified argon collisional-radiative model.

Gordon, M. H.; Kruger, C. H.

1993-03-01

35

Modeling of an argon cascaded arc plasma by ANSYS FLUENT  

NASA Astrophysics Data System (ADS)

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.

Wei, Guodong; Qi, Xin; Yang, Lei

2014-04-01

36

Properties of radio-frequency heated argon confined uranium plasmas  

NASA Technical Reports Server (NTRS)

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.

1976-01-01

37

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...

38

Effects of surrounding gas on the long laminar argon plasma jet characteristics  

Microsoft Academic Search

Comparative study is performed concerning the characteristics of long laminar argon plasma jets issuing into argon or into air surroundings. It is shown that when argon, instead of air, is used as the surrounding gas, besides pure argon atmosphere can be formed, the mass flow rate of surrounding gas entrained into the plasma jet and the length of jet high-temperature

Dong-Yan Xu; Xi Chen

2005-01-01

39

Inactivation Characteristics of Bacteria in Capacitively Coupled Argon Plasma  

Microsoft Academic Search

Plasma technology is being focused on the medical, food, and pharmaceutical fields for sterilization applications. The sterilizing effect of the 13.56-MHz radio-frequency (RF) plasma generated by using argon gas was studied using Staphylococcus aureus, one of the most common pathogens liable to hospital-acquired infections. The major focus of this paper was to perform a parametric study by varying the external-process

Sureshkumar; Sudarsan Neogi

2009-01-01

40

Measurements on an argon helicon plasma with variable magnetic nozzle  

Microsoft Academic Search

Summary form only given. The possible existence of a plasma double layer arising at the field gradient of a magnetic nozzle is investigated in a high-density (1013 cm-3), 13.56 MHz radiofrequency (RF) argon helicon plasma with high fractional ionization (>90%). A half-turn double helix antenna couples RF power to the low pressure (mtorr) gas in a 10-cm-diameter, 2-m-long cylindrical Pyrex

C. M. Denning; J. E. Scharer

2006-01-01

41

Equation of state of partially ionized argon plasma  

SciTech Connect

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.

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

2011-11-15

42

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

SciTech Connect

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.

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

43

The temperature profiles in an argon plasma issuing into an argon atmosphere: A comparison of measurements and predictions  

Microsoft Academic Search

Experimental measurements and computed results are reported on a nontransferred argon plasma discharging into an argon environment in a laminar regime. The experimental data provide information on the temperature profiles, particularly those close to the torch exit. The mathematical representation of the system involves the simultaneous statement of the equations of continuity, motion, and thermal energy balance for an axisymmetric

A. H. Dilawari; J. Szekely; J. Batdorf; R. Detering; C. B. Shaw

1990-01-01

44

Flush-mounted probe diagnostics for argon glow discharge plasma.  

PubMed

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

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

45

Blood plasma coagulation studied by surface plasmon resonance  

NASA Astrophysics Data System (ADS)

A surface plasmon resonance (SPR) apparatus was used to investigate blood plasma coagulation in real-time as a function of thromboplastin and heparin concentrations. The physical reason for the SPR signal observed is discussed and 3 different models are proposed. The response curves were analyzed by multivariable curve fitting followed by feature extraction. Interesting parameters of the sigmoid curves were lag time, slope and maximum response. When thromboplastin concentrations were increased, the lag-time decreased and the slope of the curve increased. A prolonged clotting time was followed mostly by increased maximum response, with exception for samples with no or very little thromboplastin added. High heparin concentrations changed the clotting kinetics. As seen from the lag-time vs. slope relation. Atomic force microscopy pictures of sensor surfaces dried after completed clotting, revealed differences in fibrin network structures as a function of thromboplastin concentration, and fiber thickness increased with lower thromboplastin concentration. The results correlate well with present common methods.

Vikinge, Trine P.; Hansson, Kenny M.; Benesch, Johan; Johansen, Knut; Ranby, Mats; Lindahl, Tomas L.; Lundstroem, Ingemar; Tengvall, Pentti

1999-01-01

46

Langmuir Probe Measurements of an Expanding Argon Plasma  

NASA Astrophysics Data System (ADS)

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.

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

47

Atmospheric pressure argon plasma jet using a cylindrical piezoelectric transformer  

NASA Astrophysics Data System (ADS)

A low-voltage atmospheric pressure nonthermal argon plasma jet using a circular piezoelectric transducer is proposed. An Ar plasma flame is generated at an input voltage of 87 V. The consumed power is 2 W. The electrical and optical properties of the jet are analyzed. In particular, the transient Ar discharge ignition and evolution including the so-called plasma bullet phenomenon is examined temporally resolved with the aid of a fast camera. It is found that four discharge phases can be identified, designated as ignition, extension, self-propagation, and attenuation. The plasma bullet is launched while the electric field in the discharge space is decreasing. The average bullet velocity is 23 km/s.

Kim, Hyun; Brockhaus, Albrecht; Engemann, Jürgen

2009-11-01

48

Mechanism and kinetics of tetrachlorosilane reactions in an argon-hydrogen microwave plasma  

Microsoft Academic Search

The dissociation mechanism of silicontetrachloride to silicon by plasma with argon or in mixtures of argon and hydrogen was investigated by sampling the microwave induced plasma and its chemical components by (i) electrostatic double floating probe system (DFPS), (ii) quadrupole mass spectrometry (QMS), and (iii) electron spin resonance (ESR). Plasma diagnostics, i.e., determination of mean electron energy and positive ion

N. Mayo; U. Carmi; I. Rosenthal; R. Avni; R. Manory; A. Grill

1984-01-01

49

FVII Dependent Coagulation Activation in Citrated Plasma by Polymer Hydrogels  

E-print Network

), and a phospholipid surface.3 Human coagulation FVII is a single chain, glycoprotein which circulates in normal human into a phospholipid membrane, a surface which is typically provided by platelets.14-16 TFPI is the main inhibitor considerable research into the effects of charged surfaces on the coagulation cascade. The ability

Kofinas, Peter

50

Plasma core reactor simulations using RF uranium seeded argon discharges  

NASA Technical Reports Server (NTRS)

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.

Roman, W. C.

1976-01-01

51

Plasma core reactor simulations using RF uranium seeded argon discharges  

NASA Technical Reports Server (NTRS)

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.

Roman, W. C.

1975-01-01

52

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

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

53

Temporal and spectral characteristics of atmospheric pressure argon plasma jet  

NASA Astrophysics Data System (ADS)

An investigation of atmospheric pressure argon DBD plasma jet generated at 6 kHz sinusoidal voltage was carried out. On the basis of recorded electrical, optical and spectral characteristics spatiotemporal evolution of plasma jet in negative and positive half-cycles of voltage was studied. It was found that the dynamics of argon jet propagation outside the tube differs considerably from that found by other authors in the case of helium jet. The difference was explained with the influence of Penning reactions between metastable state He atoms and air molecules in He jet. On the basis of radiative transitions N2 (C-B, 0-0) and OH(A-X, 0-0) the rotational temperatures of N2(C, 0) and OH(A, 0) were estimated along jet axis. In regions where Ar-air mixing was negligible or low, the rotational temperatures of both molecules coincide and were close to the gas temperature. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.

Raud, Jüri; Jõgi, Indrek; Laan, Matti; Laast, Marti

2013-02-01

54

Histochemical evaluation of the coagulation depth after argon laser impact on a port-wine stain.  

PubMed

A two-step excisional treatment of a port-wine stain (PWS) on the back of a 43-yr-old female patient was performed. Immediately before the first surgical treatment, two corresponding series of argon laser impacts were performed, each on one PWS half. Different laser parameters with irradiances ranging from 95 to 382 W/cm2 and energy fluences ranging from 19 to 114,6 J/cm2 were used. Laser spots on the first part ot be excised were biopsied 10 min after laser treatment and prepared for histochemical analysis by staining with nitro blue tetrazolium chloride (NBTC). Reduction of this redox dye by nicotinamide adenine dinucleotide diaphorase (NADH-diaphorase) leads on frozen tissue sections to an intense blue precipitate. The activity of NADH-diaphorase subsides immediately upon cell damage. All vital epidermal and dermal cells presented a dense blue granular pigment in their cytoplasm, sparing the nuclei. Laser induced arc-shaped epidermal and dermal necrosis did not stain, showing a clear demarcation from surrounding vital tissue. The depth of the thermal injury ranged from 0.28 to 0.45 mm; it did not correlate with the chosen fluences. With these penetration depths, the vast majority of PWS vessels was affected. Assessment of the remaining part of the PWS 8 months later yielded blanching of all laser-treated areas. With the NBTC method, an accurate definition of laser-induced tissue damage is feasible. It could be shown that the exposure time is the most relevant parameter influencing the penetration depth. PMID:1753855

Neumann, R A; Knobler, R M; Leonhartsberger, H; Böhler-Sommeregger, K; Gebhart, W

1991-01-01

55

Surface characterization of argon-plasma-modified perfluorosulfonic acid membranes.  

PubMed

The perfluorosulfonic acid membranes which are used in direct methanol fuel cells were modified with argon plasma under various conditions, and the physicochemical and transport properties of the resulting membranes were investigated using various analytical techniques. The plasma treatment was found to change the surface morphology and physicochemical properties of the membranes. The surface roughness of the membranes was increased by the etching effect of plasma. From the FTIR and XPS analyses, the incorporation of new oxygen functionalities, such as the peroxide group, was confirmed. The breakage of both the sulfonic acid groups and ether linkages were also found to cause an increase in the equivalent weight of the modified skin layer of the membrane. The incident water contact angle of the modified membrane in a dry state decreased with an increased plasma treatment, because of the hydrophilic groups that developed on the membrane surface. The time-dependent water contact angle, however, increased in proportion to the extent of the plasma treatment, due to the reduced concentration of sulfonic acid groups. Although the equilibrium water uptake of the modified membrane was almost invariable because of the negligible thickness of the modified skin layer, the transport properties of the membrane such as methanol permeability and proton conductivity were significantly reduced. PMID:16509719

Bae, Byungchan; Kim, Dukjoon; Kim, Hyoung-Juhn; Lim, Tae-Hoon; Oh, In-Hwan; Ha, Heung Yong

2006-03-01

56

Sterilization of bacterial endospores by an atmospheric-pressure argon plasma jet  

Microsoft Academic Search

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.

Han S. Uhm; Jin P. Lim; Shou Z. Li

2007-01-01

57

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

E-print Network

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-average power, the time-average ion energy flux bombarding the wafer has a minimum with respect to the pulse

Economou, Demetre J.

58

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

E-print Network

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, sterilization I. INTRODUCTION Non-thermal plasma technology at atmospheric pressure using oxygen

Paris-Sud XI, Université de

59

Optical Emission Measurements of AN Inductively Coupled Argon Plasma  

NASA Astrophysics Data System (ADS)

The inductively coupled plasma (ICP) literature contains several unresolved issues. These issues are contained in the observations (1) measured excitation temperatures are constant across a wide range of operating conditions, (2) measured power dissipation profiles are significantly more localized than calculated profiles, and (3) the few available measurements of gas temperatures are made above the coil and indicate the gas temperature can be significantly lower than corresponding excitation temperatures. This thesis work began with this third observation, checking for different excitation and gas temperatures in the coil region of an argon ICP. These are the first published simultaneous measurements of excitation and gas temperatures in the coil region of a large diameter (75 mm), high power (14 kW), 2 MHz, argon ICP. A novel spectroscopic strategy was developed, using trace amounts of methane and nitrogen to measure CN rotational emission and Stark broadening simultaneously with argon emission. The CN emission profile was unexpectedly localized requiring the novel synthesis of several signal processing techniques into a flexible and robust Abel inversion technique. The resulting excitation and gas temperature measurements contribute to the limited available evidence for nonequilibrium in an ICP. In the plasma core, the measured bound and free electron populations are in equilibrium at ~10,000 K, while the gas temperature is only ~2,500 K. The gas temperature rises to 8-9,000 K in a localized annulus near the plasma edge. A simplified model supports these measurements and proposes a novel structure of three concentric regions within the coil. Against the torch wall, is a narrow 'blanket annulus' of cold gas. The 'blanket annulus' surrounds a narrow 'discharge annulus' where the gas temperature is 8,500 K and the electron temperature is 16,000 K. The 'discharge annulus' surrounds a broad 'photo-excited core' where kinetic temperatures are ~2,500 K and excitation temperatures are elevated by nonlocal, resonance radiation which diffuses inward from the 'discharge annulus'. This structure provides a new basis for understanding the unresolved issues in the ICP literature.

Jaffe, Stephen Mosheim

1995-01-01

60

Plasma tissue factor pathway inhibitor in disseminated intravascular coagulation: Comparison of its behavior with plasma tissue factor  

Microsoft Academic Search

In order to assess the clinical implication of tissue factor pathway inhibitor (TFPI) in disseminated intravascular coagulation (DIC), plasma concentrations of TFPI were measured together with plasma tissue factor (TF) in 30 healthy subjects and 49 patients with DIC associated with a variety of underlying diseases. The mean TFPI concentration was elevated in patients with DIC at presentation (205.8 ±

Hoyu Takahashi; Naoaki Sato; Akira Shibata

1995-01-01

61

Experimental characterization of an argon laminar plasma jet at atmospheric pressure  

Microsoft Academic Search

This paper deals with a dc laminar pure argon plasma jet operating at atmospheric pressure in ambient air that was experimentally studied in order to obtain temperature and velocity. Plasma jet temperature was evaluated by optical emission spectroscopy and the plasma jet velocity was determined by various methods using a pressure sensor. It is shown that the maximum plasma jet

Emilie Langlois-Bertrand; Charles de Izarra

2011-01-01

62

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

NASA Astrophysics Data System (ADS)

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.

Jauberteau, J. L.; Jauberteau, I.

2014-12-01

63

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

E-print Network

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

Howard, John

64

Modeling on the Momentum and Heat\\/Mass Transfer Characteristics of an Argon Plasma Jet Issuing into Air Surroundings and Interacting with a Counter-Injected Argon Jet  

Microsoft Academic Search

Modeling study is performed to reveal the momentum and heat\\/mass transfer characteristics of a turbulent or laminar plasma\\u000a reactor consisting of an argon plasma jet issuing into ambient air and interacting with a co-axially counter-injected argon\\u000a jet. The combined-diffusion-coefficient method and the turbulence-enhanced combined-diffusion-coefficient method are employed\\u000a to treat the diffusion of argon in the argon–air mixture for the laminar

Hai-Xing WangXi; Xi Chen; He-Ping Li

2011-01-01

65

Methylmethacrylate bone cement surface does not promote platelet aggregation or plasma coagulation in vitro  

Microsoft Academic Search

Leakage of viscous bone cement into venous blood possibly resulting in pulmonary embolism may occur during percutaneous vertebroplasty. Our aim was to study if bone cement surface or cement liquid component could induce platelet aggregation or plasma coagulation in vitro. Two types of commonly used methyl-methacrylate bone cement, Palacos R (Heraeus Kulzer, Germany) and Vertebroplastic TM (DePuy, Acro Med, England),

Aleš Blinc; Mojca Boži?; Rok Vengust; Mojca Stegnar

2004-01-01

66

Enhanced Field Emission from Argon Plasma-Treated Ultra-sharp ?-Fe2O3Nanoflakes  

PubMed Central

Hematite nanoflakes have been synthesized by a simple heat oxide method and further treated by Argon plasmas. The effects of Argon plasma on the morphology and crystal structures of nanoflakes were investigated. Significant enhancement of field-induced electron emission from the plasma-treated nanoflakes was observed. The transmission electron microscopy investigation shows that the plasma treatment effectively removes amorphous coating and creates plenty of sub-tips at the surface of the nanoflakes, which are believed to contribute the enhancement of emission. This work suggests that plasma treatment technique could be a direct means to improve field-emission properties of nanostructures. PMID:20596290

2009-01-01

67

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

Microsoft Academic Search

A nonequilibrium Ar\\/O2 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

Jin-Pyo Lim; Han S. Uhm; Shou-Zhe Li

2007-01-01

68

Modeling Study on the Entrainment of Ambient Air into Subsonic Laminar and Turbulent Argon Plasma Jets  

Microsoft Academic Search

Modeling study is performed to reveal the special features of the entrainment of ambient air into subsonic laminar and turbulent\\u000a argon plasma jets. Two different types of jet flows are considered, i.e., the argon plasma jet is impinging normally upon\\u000a a flat substrate located in atmospheric air surroundings or is freely issuing into the ambient air. It is found that

Hai-Xing Wang; Xi Chen; Wenxia Pan

2007-01-01

69

Absorption Measurements of 4s State Number density for a Microwave Argon Plasma  

NASA Astrophysics Data System (ADS)

Optical emission and continuum measurements have been performed to characterize microwave argon plasmas. A Wavemat (model MPDR-3135) microwave diamond deposition system was used to generate the argon plasma at 5 Torr with an argon flow rate of 300 sccm. In a previous study, three excited states number densities (4p, 5p, and 5d) were obtained from the emission measurements. These data were used to validate our zero-dimensional (with diffusion) Collisional-Radiative Model (CRM) by matching these three excited state number densities with the prediction from the CRM. An energy balance study showed that the energy absorbed by the argon plasma was far less than the reading from the power meters, also in agreement with our CRM predictions. To better characterize the plasma, we have recently measured the 4s population through absorption at 7635Å. The light source was a low-pressure AC argon lamp. To calculate the 4s number density, the lineshapes of the argon lamp and the argon plasma are needed. The lineshape of the argon lamp was taken from previous work which used a similar lamp. However, the plasma lineshape depends on the electron number density, the number densities of related excited states, the electron and gas temperatures, etc. For our microwave plasma system, these parameters cannot be measured directly. Therefore, the plasma lineshape was calculated based on the parameters predicted from the CRM. The 4s state number density calculted from this lineshape matches the predicted one from the CRM within the experimental uncertainty, further validating our model.

Li, Yunlong; Gordon, Matthew; Roe, Larry; Hassouni, Khaled

1999-10-01

70

Dielectric properties in microwave remote plasma sustained in argon: Expanding plasma conditions  

SciTech Connect

This work is devoted to the study of the relative permittivity in argon expanding plasma produced below a microwave discharge sustained in a quartz tube and working at 2.45 GHz. We discuss results and explain the microwave propagation within the reactor, outside the quartz tube. It is shown that at low pressures (133 Pa) and at powers ranging from 100 W to 400 W, the wave frequency remains lower than the plasma frequency anywhere in the expanding plasma. Under these conditions, the real part of the relative permittivity is negative and the wave is reflected. Surprisingly, in these conditions, the plasma is produced inside and outside the quartz tube, below the wave launcher. This effect can be explained considering a surface wave propagating at the surface of the quartz tube then into the reactor, on the external surface of the expanding plasma below the quartz tube.

Jauberteau, J. L.; Jauberteau, I. [UMR 7315 CNRS, SPCTS, 12 rue Atlantis, 87068 Limoges (France)

2012-11-15

71

Diode Laser Based LIF Diagnostics for Argon and Helium Plasmas.  

NASA Astrophysics Data System (ADS)

A diode laser based Laser Induced Fluorescence (LIF) diagnostic that uses an inexpensive diode laser system is presented. The same diode laser is used to pump Ar II and He I transitions to obtain the ion and the neutral temperature of the respective species. The 1 MHz bandwidth diode laser has a Littrow external cavity with a mode-hop free tuning range up to 15 GHz and with a total power output of about 10 mWatt. The wavelength is measured by a wavemeter and frequent monitoring prevent wavelength drift. For the argon ion population, the laser tuned at 668.61 nm, is used to pump the 3d4F7/2 Ar II metastable level to the 4p4D5/2 excited level. The fluorescence radiation between the 4p4D5/2 and the 4s4P3/2 levels (442.6 nm) is monitored by a photomultiplier detector. For neutral helium, the laser is tuned at 667.82 nm to pump a fraction of the electron population from the 21P state to the 31D upper level. Although the 21P level is not a metastable state, the close proximity of 21S metastable level makes this new He I LIF possible in collisional plasmas. Some electrons of this 31D level undergo collisional excitation transfer (optically allowed transition) to the 31P. In turn, this state decay to the metastable 21S by emitting 501.6 nm fluorescence photons. The new LIF diagnostic has been developed at West Virginia University (WVU) and tested on the Hot hELIcon eXperiment (HELIX) plasma device. Ion and neutral temperatures obtained using this new LIF diagnostic are presented and compared to previous measurements performed with a more expensive and elaborate ring dye laser system.

Stolzenberg, E.; Boivin, R. F.; Compton, C.; Hardin, R.; Keesee, A.; Kline, J. L.; Scime, E. E.

2002-11-01

72

Practical Optimization of AECS PF-2 Plasma Focus Device for Argon Soft X-ray Operation  

NASA Astrophysics Data System (ADS)

For operation of the plasma focus in argon, a focus pinch compression temperature range of 1.4-5 keV (16.3 × 106-58.14 × 106 K) is found to be suitable for good yield of argon soft X-rays (SXR) Ysxr. This is based on reported temperature measurements of argon plasmas working at regime for X-ray output. Using this temperature window, numerical experiments have been investigated on AECS PF-2 plasma focus device with argon filling gas. The model was applied to characterize the 2.8 kJ plasma focus AECS PF-2. The optimum Ysxr was found to be 0.0035 J. Thus, we expect to increase the argon Ysxr of AECS PF-2, without changing the capacitor bank, merely by changing the electrode configuration and operating pressure. The Lee model code was also used to run numerical experiments on AECS PF-2 with argon gas for optimizing soft X-ray yield with reducing L0, varying z0 and `a'. From these numerical experiments we expect to increase the argon Ysxr of AECS PF-2 with reducing L0, from the present computed 0.0035 J at L0 = 270 nH to maximum value of near 0.082 J, with the corresponding efficiency is about 0.03%, at an achievable L0 = 10 nH.

Akel, M.; Lee, S.

2012-04-01

73

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

SciTech Connect

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.

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

74

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

75

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

E-print Network

by RF discharge in argon J.-F. Lagrange(*)1 , M. Mikikian2 , I. Géraud-Grenier1 , F. Faubert3 , V in dusty plasma by RF discharge in Argon. Their movement, quantity and velocity can be controlled are realised in Argon. Instabilities appear in the plasma for specific experimental conditions (gas flow rate

Boyer, Edmond

76

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

SciTech Connect

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.

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

77

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

SciTech Connect

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.

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

78

A cartridge based sensor array platform for multiple coagulation measurements from plasma.  

PubMed

This paper proposes a MEMS-based sensor array enabling multiple clot-time tests for plasma in one disposable microfluidic cartridge. The versatile LoC (Lab-on-Chip) platform technology is demonstrated here for real-time coagulation tests (activated Partial Thromboplastin Time (aPTT) and Prothrombin Time (PT)). The system has a reader unit and a disposable cartridge. The reader has no electrical connections to the cartridge. This enables simple and low-cost cartridge designs and avoids reliability problems associated with electrical connections. The cartridge consists of microfluidic channels and MEMS microcantilevers placed in each channel. The microcantilevers are made of electroplated nickel. They are actuated remotely using an external electro-coil and the read-out is also conducted remotely using a laser. The phase difference between the cantilever oscillation and the coil drive is monitored in real time. During coagulation, the viscosity of the blood plasma increases resulting in a change in the phase read-out. The proposed assay was tested on human and control plasma samples for PT and aPTT measurements. PT and aPTT measurements from control plasma samples are comparable with the manufacturer's datasheet and the commercial reference device. The measurement system has an overall 7.28% and 6.33% CV for PT and aPTT, respectively. For further implementation, the microfluidic channels of the cartridge were functionalized for PT and aPTT tests by drying specific reagents in each channel. Since simultaneous PT and aPTT measurements are needed in order to properly evaluate the coagulation system, one of the most prominent features of the proposed assay is enabling parallel measurement of different coagulation parameters. Additionally, the design of the cartridge and the read-out system as well as the obtained reproducible results with 10 ?l of the plasma samples suggest an opportunity for a possible point-of-care application. PMID:25353144

Cakmak, O; Ermek, E; Kilinc, N; Bulut, S; Baris, I; Kavakli, I H; Yaralioglu, G G; Urey, Hakan

2015-01-01

79

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

E-print Network

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

Boyer, Edmond

80

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

E-print Network

of plasma spray torches was in 1957 by Thermal Dynamic Corp. (Lebanon, NH). Since that, plasma spraying, and their temperature histories and then the quality and the formability of thermal spray. Dealing with plasma jet regimes [3]-[7]. It has been shown, then, that thermal and dynamic behaviors of plasma jets depend

81

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

PubMed

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

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

82

The effect of potassium addition on plasma parameters in argon dc plasma arc  

NASA Astrophysics Data System (ADS)

The effect of potassium addition on the radial distribution of temperature and electron number density in a U-shaped direct current (dc) argon plasma operating at different arc currents has been studied by optical emission spectroscopic techniques and the power interruption method. Spatially resolved electron number densities (ne) have been determined from measured radial profiles of Balmer-H? spectral line. The obtained electron number densities have been used for thermodynamic temperature (TLTE) evaluation with the assumption that the arc plasma is in a state of local thermodynamic equilibrium. The excitation temperatures (Texc) have been determined from the absolute integral emissivity of the argon line at 430.01 nm. For heavy particle temperature (Th) evaluations we have used a power interruption method. The obtained results have shown that an addition of KCl decreases both electron number density and temperature of the arc column. The magnitude of such an influence on plasma parameters increases with an increase in the KCl concentration and decreases with an increase in the arc current.

Rankovi?, D.; Kuzmanovi?, M.; Savovi?, J.; Pavlovi?, M. S.; Stoiljkovi?, M.; Mom?ilovi?, M.

2010-08-01

83

Droplet Striations Formed in a 900MHz Microwave Argon Atmospheric-Pressure Plasma Jet  

Microsoft Academic Search

Unique striations were observed in the formation of 900-MHz microwave argon atmospheric-pressure plasma jet in air. The striated patterns are easily observed even with the naked eyes at a flow rate of above 3 slm and an input power of below 3 W. Moreover, the striated patterns, which were associated with shortening in the plasma jet length, are obtained by

Sung Kil Kang; Abdel-Aleam H. Mohamed; Hyun Wook Lee; Jae Koo Lee

2011-01-01

84

Polydiagnostic calibration performed on a low pressure surface wave sustained argon plasma  

Microsoft Academic Search

The electron density and electron temperature of a low pressure surface wave sustained argon plasma have been determined using passive and active (laser) spectroscopic methods simultaneously. In this way the validity of the various techniques is established while the plasma properties are determined more precisely. The electron density, ne, is determined with Thomson scattering (TS), absolute continuum measurements, Stark broadening

N de Vries; J M Palomares; E I Iordanova; E M van Veldhuizen; J J A M van der Mullen

2008-01-01

85

The response of the inductively coupled argon plasma to solvent plasma load: spatially resolved maps of electron density obtained from the intensity of one argon line  

NASA Astrophysics Data System (ADS)

A survey of spatially resolved electron number density ( ne) in the tail cone of the inductively coupled argon plasma (ICAP) is presented: all of the results of the survey have been radially inverted by numerical, asymmetric Abel inversion. The survey extends over the entire volume of the plasma beyond the exit of the ICAP torch; It extends over distances of z = 5-25 mm downstream from the induction coil, and over radial distances of ± 8 mm from the discharge axis. The survey also explores a range of inner argon flow rates ( QIN), solvent plasma load ( Qspl) and r.f. power: moreover, it explores loading by water, methanol and chloroform. Throughout the survey, ne was determined from the intensity of one, optically thin argon line, by a method which assumes that the atomic state distribution function (ASDF) for argon lies close to local thermal equilibrium (LTE). The validity of this assumption is reviewed. Also examined are the discrepancies between ne from this method and ne from Stark broadening measurements. With the error taken into account, the results of the survey reveal how time averaged values of ne in the ICAP respond over an extensive, previously unexplored range of experimental parameters. Moreover, the spatial information lends insight into how the thermal conditions and the transport of energy respond. Overall, the response may be described in terms of energy consumption along the axial channel and thermal pinch within the induction region. The predominating effect depends on the solvent plasma load, the solvent composition, the robustness of the discharge, and the distribution of solvent material over the argon stream.

Weir, D. G. J.; Blades, M. W.

1994-12-01

86

Carbon monoxide releasing molecule-2 improves coagulation in patient plasma in vitro following cardiopulmonary bypass.  

PubMed

The objective of the present study was to determine if a new procoagulant molecule, carbon monoxide releasing molecule (tricarbonyldichlororuthenium (II) dimer; CORM-2) would improve coagulation following cardiopulmonary bypass (CPB). Plasma was obtained from patients undergoing elective cardiac surgery requiring CPB. Whole blood was collected and anticoagulated with sodium citrate after induction of anesthesia and again after CPB and heparin neutralization with protamine. Blood samples were centrifuged for 15 min, with plasma collected and stored at -80°C prior to analysis. Samples were subsequently exposed to 0 or 100 ?mol/l CORM-2, with coagulation activated with tissue factor. Data were collected with thrombelastography until clot strength stabilized. Patients underwent CPB for 133 ± 61 min (mean ± SD). The velocity of thrombus formation was significantly decreased (52%) by CPB, as was clot strength (53%). Addition of CORM-2 to plasma samples obtained after CPB significantly increased the velocity of clot formation (75%) and strength (52%) compared to matched unexposed samples. The lesion of plasmatic coagulation associated with CPB was significantly improved in vitro by addition of CORM-2. If preclinical assessments of efficacy and safety of CORM-2 are favorable, future clinical trials involving CORM-2 or other CORMs as a hemostatic intervention in the setting of CPB are justified. PMID:21346555

Malayaman, S Nini; Entwistle, John W C; Boateng, Percy; Wechsler, Andrew S; Persaud, Joshua M; Cohen, Jack B; Kirklin, James K; Nielsen, Vance G

2011-07-01

87

Impacts of leukocyte filtration and irradiation on coagulation factors in fresh frozen plasma  

PubMed Central

This study aimed to compare and analyze the changes in the coagulation factors in fresh frozen plasma (FFP) prior to and following leukocyte filtration and irradiation. In total, 30 bags of FFP from healthy donors were processed: One-third of the FFP of each bag was left within the original bag (the A group), the other two-thirds of the FFP of each bag were passed through a disposable leukocyte filter, then divided equally into two parts. One of these was designated as the B group, and the other was designated the C group (subjected to 30 Gy irradiation). All samples were analyzed to evaluate 16 coagulation indicators. Analysis of variance revealed that there were statistically significant differences in the levels of fibrinogen (FbgC) and coagulation factor VIII (FVIII:C) among the groups (P=0.044 and P=0.015, respectively); the Dunnett’s t-test revealed that there was a statistically significant difference in the level of FbgC between the A and B groups (P=0.025), and there was a statistically significant difference in the level of FVIII:C between the A and C groups (P=0.009); while the remaining 14 coagulation parameters were not significantly different among the groups. Although the levels of FbgC and FVIII:C in the FFP were reduced following treatment, this would not affect the clinical effect of the FFP.

LI, DAI-YU; ZHANG, HONG-WEI; FENG, QING-ZHEN; ZHAO, HUA

2015-01-01

88

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

SciTech Connect

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.

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

89

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

E-print Network

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

Boyer, Edmond

90

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

NASA Astrophysics Data System (ADS)

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.

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

2008-11-01

91

Plasma vitronectin polymorphism in normal subjects and patients with disseminated intravascular coagulation.  

PubMed

Vitronectin, also known as serum-spreading factor or S-protein, mediates cell adhesion and inhibits formation of the membrane-lytic complex of complement and the rapid inactivation of thrombin by antithrombin III in the presence of heparin. Vitronectin is normally present in plasma at a concentration of approximately 300 micrograms/mL. The investigators quantified plasma vitronectin with an enzyme-linked immunosorbent assay and visualized reduced and nonreduced vitronectin by immunoblotting after separation of plasma or serum by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The concentration of plasma vitronectin was markedly reduced in some patients with disseminated intravascular coagulation, especially in those with liver failure; it was near normal in patients with metastatic cancer and acute leukemia. Patients with vitronectin levels less than 40% normal invariably had low fibrinogen and antithrombin III and a prolonged prothrombin time. In both normal and patient plasmas there was heterogeneity in the ratio of the 75,000- and 65,000-mol wt polypeptides of reduced vitronectin: 18% had mostly the 75,000-mol wt polypeptide, 59% had roughly equal amounts of the two polypeptides, and 22% had mostly the 65,000-mol wt polypeptide. This polymorphism is inherited and appears to be due to two alleles that are present with approximately equal frequency. The blotting patterns of vitronectin in reduced and nonreduced plasmas were largely unaltered in plasma of patients with defibrination syndrome, fibrinolysis, liver failure, sepsis, metastatic cancer, and acute leukemia. There was no evidence of fragmentation of vitronectin or formation of the disulfide-bonded complex of vitronectin and thrombin-antithrombin III that is found when blood is clotted. Thus these results corroborate in vitro observations that the liver is the major source of plasma vitronectin, suggest that vitronectin may become depleted during disseminated intravascular coagulation, and define a genetic polymorphism of vitronectin. PMID:2455567

Conlan, M G; Tomasini, B R; Schultz, R L; Mosher, D F

1988-07-01

92

Plasma pentraxin-3 and coagulation and fibrinolysis variables during acute Puumala hantavirus infection and associated thrombocytopenia.  

PubMed

Thrombocytopenia and altered coagulation characterize all hantavirus infections. To further assess the newly discovered predictive biomarkers of disease severity during acute Puumala virus (PUUV) infection, we studied the associations between them and the variables reflecting coagulation, fibrinolysis and endothelial activation. Nineteen hospital-treated patients with serologically confirmed acute PUUV infection were included. Acutely, plasma levels of pentraxin-3 (PTX3), cell-free DNA (cf-DNA), complement components SC5b-9 and C3 and interleukin-6 (IL-6) were recorded as well as platelet ligands and markers of coagulation and fibrinolysis. High values of plasma PTX3 associated with thrombin formation (prothrombin fragments F1+2; r = 0.46, P = 0.05), consumption of platelet ligand fibrinogen (r = -0.70, P < 0.001) and natural anticoagulants antithrombin (AT) (r = -0.74, P < 0.001), protein C (r = -0.77, P < 0.001) and protein S free antigen (r = -0.81, P < 0.001) and a decreased endothelial marker ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 domain 13) (r = -0.48, P = 0.04). Plasma level of AT associated with C3 (r = 0.76, P < 0.001), IL-6 (r = -0.56, P = 0.01) and cf-DNA (r = -0.47, P = 0.04). High cf-DNA coincided with increased prothrombin fragments F1+2 (r = 0.47, P = 0.04). Low C3 levels reflecting the activation of complement system through the alternative route predicted loss of all natural anticoagulants (for protein C r = 0.53, P = 0.03 and for protein S free antigen r = 0.64, P = 0.004). Variables depicting altered coagulation follow the new predictive biomarkers of disease severity, especially PTX3, in acute PUUV infection. The findings are consistent with the previous observations of these biomarkers also being predictive for low platelet count and underline the cross-talk of inflammation and coagulation systems in acute PUUV infection. PMID:24751477

Laine, Outi K; Koskela, Sirpa M; Outinen, Tuula K; Joutsi-Korhonen, Lotta; Huhtala, Heini; Vaheri, Antti; Hurme, Mikko A; Jylhävä, Juulia; Mäkelä, Satu M; Mustonen, Jukka T

2014-09-01

93

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

94

Selfconsistent Electrostatic-Particle-In-Cell Monte Carlo Simulations of Weak Argon Plasma  

E-print Network

Selfconsistent Electrostatic-Particle-In-Cell Monte Carlo Simulations of Weak Argon Plasma S++. Simulations of arbitrary substrate geometries, ion sources and electrostatic boundary conditions are possible First hints of spatial ion distribution between target and substrate (electrostatic biased) as well

Geiser, Juergen

95

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...

96

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

Microsoft Academic Search

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

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

1980-01-01

97

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

Microsoft Academic Search

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

A. B. Murphy

1995-01-01

98

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

99

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

PubMed

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

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

100

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

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

101

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

E-print Network

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

Boyer, Edmond

102

Spatio-temporal dynamics of a pulsed microwave argon plasma: ignition and afterglow  

NASA Astrophysics Data System (ADS)

In this paper, a detailed investigation of the spatio-temporal dynamics of a pulsed microwave plasma is presented. The plasma is ignited inside a dielectric tube in a repetitively pulsed regime at pressures ranging from 1 up to 100 mbar with pulse repetition frequencies from 200 Hz up to 500 kHz. Various diagnostic techniques are employed to obtain the main plasma parameters both spatially and with high temporal resolution. Thomson scattering is used to obtain the electron density and mean electron energy at fixed positions in the dielectric tube. The temporal evolution of the two resonant and two metastable argon 4s states are measured by laser diode absorption spectroscopy. Nanosecond time-resolved imaging of the discharge allows us to follow the spatio-temporal evolution of the discharge with high temporal and spatial resolution. Finally, the temporal evolution of argon 4p and higher states is measured by optical emission spectroscopy. The combination of these various diagnostics techniques gives deeper insight on the plasma dynamics during pulsed microwave plasma operation from low to high pressure regimes. The effects of the pulse repetition frequency on the plasma ignition dynamics are discussed and the plasma-off time is found to be the relevant parameter for the observed ignition modes. Depending on the delay between two plasma pulses, the dynamics of the ionization front are found to be changing dramatically. This is also reflected in the dynamics of the electron density and temperature and argon line emission from the plasma. On the other hand, the (quasi) steady state properties of the plasma are found to depend only weakly on the pulse repetition frequency and the afterglow kinetics present an uniform spatio-temporal behavior. However, compared to continuous operation, the time-averaged metastable and resonant state 4s densities are found to be significantly larger around a few kHz pulsing frequency.

Carbone, Emile; Sadeghi, Nader; Vos, Erik; Hübner, Simon; van Veldhuizen, Eddie; van Dijk, Jan; Nijdam, Sander; Kroesen, Gerrit

2015-02-01

103

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

SciTech Connect

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.

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

104

Numerical investigation of the radiation from an argon plasma generated by using a high explosive  

NASA Astrophysics Data System (ADS)

Ultraviolet radiation from argon plasmas that are generated by using a high explosive were numerically investigated. The dynamics of the plasma was evaluated using a one-dimensional fluid code The chemical explosion was treated as an external ion-energy source in the region of the explosive, that generated a strong shock wave in the argon plasma with a peak pressure of 0.58 GPa. The population densities in the atomic levels of Ar I and Ar II were obtained in thermal equilibrium with the electron temperature of the plasma. Next, spectral data in the 200 nm to 800 nm wavelength range from the argon plasma were evaluated using a radiation transfer code. Atomic levels and transition lines were obtained from the database provided by the National Institute of Science and Technology. The total radiation intensity was estimated to be 4.1×102 J/cm2 with a conversion efficiency of 0.11%, from the chemical energy of the explosive for the case of a 1-cm-long high explosive and an initial pressure of 2.0 atm.

Kim, Hee Jin; Lim, Changwhan; Lee, Kitae

2013-06-01

105

Heat flux characteristics in an atmospheric double arc argon plasma jet  

SciTech Connect

In this study, the axial evolution of heat flux excited by a double arc argon plasma jet impinging on a flat plate is determined, while the nonstationary behavior of the heat flux is investigated by combined means of the fast Fourier transform, Wigner distribution, and short-time Fourier transform. Two frequency groups (<1 and 2-10 kHz) are identified in both the Fourier spectrum and the time-frequency distributions, which suggest that the nature of fluctuations in the heat flux is strongly associated with the dynamic behavior of the plasma arc and the engulfment of ambient air into different plasma jet regions.

Tu Xin; Yu Liang; Yan Jianhua; Cen Kefa [Zhejiang University, Hangzhou 310027 (China); Cheron, Bruno [UMR 6614 CNRS CORIA, Saint Etienne du Rouvray 76801 (France)

2008-10-13

106

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

NASA Astrophysics Data System (ADS)

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%.

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

2015-02-01

107

Plasma Diagnostics Using K-Line Emission Profiles of Argon  

E-print Network

K-line profiles emitted from a warm dense plasma environment are used for diagnostics of Ar droplet plasmas created by high energy laser pulses. We observe temperature gradients within the Ar droplet from cold temperatures of the order of some 10 eV up to higher temperatures of about 170 eV. Non-perturbative wave functions are calculated as well as ionization energies, binding energies and relevant emission energies using a chemical {\\it ab initio} code. The plasma screening is considered within a perturbative approach to the Hamiltonian. The plasma effect influences the many-particle system resulting in energy shifts due to electron-ion and electron-electron interaction. With this approach we get a good reproduction of spectral features that are strongly influenced by ionization and excitation processes within the plasma. Comparing with the widely known FLYCHK code, counting for internal degrees of freedom (bound states) and treating pressure ionization within our quantum statistical approach leads to differ...

Chen, Yiling; Reinholz, Heidi; Röpke, Gerd

2014-01-01

108

Experimental Investigation of Laser-sustained Plasma in Supersonic Argon Flow  

SciTech Connect

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 CO{sub 2}-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.

Sperber, David; Eckel, Hans-Albert [DLR - German Aerospace Center, Institute of Technical Physics, Stuttgart (Germany); Moessinger, Peter [University of Applied Sciences, Faculty of Mechanical Engineering, Esslingen (Germany); Fasoulas, Stefanos [University of Stuttgart, Institute of Space Systems, Stuttgart (Germany)

2011-11-10

109

XPS Study of Plasma- and Argon Ion-Sputtered Polytetrafluoroethylene  

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

110

ELISA for determination of total coagulation factor XII concentration in human plasma.  

PubMed

Human blood coagulation factor XII (FXII) is the one chain 80 kDa zymogen form of the active serine protease ?-FXIIa, which consists of a heavy and light chain linked by a disulfide bond, the light chain being responsible for the proteolytical activity. FXII is the first component of the contact dependent pathway of coagulation, but its physiological role is still subject to debate. In the present study we utilized two monoclonal antibodies against the heavy chain of FXII to establish a sandwich enzyme linked immunosorbent assay (ELISA) for quantification of total FXII concentration in human plasma samples. A unique characteristic of this assay is its equal recognition of FXII and inhibitor bound FXII. This is important, as inhibitor complexes of ?-FXIIa are formed in vivo as well as during blood sampling and handling. Validation of the assay demonstrated a high sensitivity, with a limit of detection and quantification of 1.2 ng/mL and 2.6 ng/mL respectively. The coefficients of variation for the repeatability and within-laboratory standard deviations were 2.6% and 5.2% respectively. The reference interval determined from healthy volunteers (n=240) was 10.6-43 mg/L. PMID:23639297

Madsen, Daniel Elenius; Sidelmann, Johannes Jakobsen; Overgaard, Kathrine; Koch, Claus; Gram, Jørgen Brodersen

2013-08-30

111

Heat flux characteristics in an atmospheric double arc argon plasma jet  

Microsoft Academic Search

In this study, the axial evolution of heat flux excited by a double arc argon plasma jet impinging on a flat plate is determined, while the nonstationary behavior of the heat flux is investigated by combined means of the fast Fourier transform, Wigner distribution, and short-time Fourier transform. Two frequency groups (<1 and 2-10 kHz) are identified in both the

Xin Tu; Liang Yu; Jianhua Yan; Kefa Cen; Bruno Chéron

2008-01-01

112

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

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

113

Application of a hybrid collisional radiative model to recombining argon plasmas  

Microsoft Academic Search

A collisional radiative model, in which a hybrid cut-off technique is used, is applied to recombining plasmas to study the atomic state distribution (ASDF) and the recombination coefficient. Computations of the ASDF using semi-empirical rate coefficients of Vriens and Smeets (V-S) and Drawin (D) are compared with experimental values measured at various positions in a free expanding argon arc jet.

D. A. Benoy; J. A. M. van der Mullen; B. van der Sijde; D. C. Schram

1993-01-01

114

[Spectroscopic investigation of the argon plasma discharge in quartz capillary at atmospheric pressure].  

PubMed

An arc plasma discharge with a long length of 20 cm was generated in a quartz capillary between two hollow needle electrodes in argon at atmospheric pressure with use of the sinusoidal power supply operating at 45 kHz, which was characterized by a very high electron density. The spectroscopic method of optical emission was employed to diagnose the characteristic parameters of the arc plasma discharge in the quartz capillary. The gas temperature was determined by simulating the OH A-X(0, 0) vibrational band around 300 nm and comparison with measured spectrum by means of optical emission spectroscopy. Furthermore, the electron density was measured by means of Stark broadening of the profile of Hbeta at 486.1 nm. The electron temperature was determined using a Boltzmann plot method. The experiment results show that in the argon arc plasma discharge generated in the quartz capillary at atmospheric pressure, the gas temperature of plasma is about (1 100 +/- 50)K, the electron density at the gas temperature of 1 100 K is approximately 10(14) cm(-3), and the corresponding electron temperature is (14 515 +/- 500)K. This work has accumulated some significant experimental parameters for the treatment of inner surface of large length-to-radius-ratio insulated dielectric tube using plasma, and the results are of great importance to the applications of this type of atmospheric-pressure plasma discharge. PMID:20672593

Huang, Wen-Tong; Li, Shou-Zhe; Guo, Qing-Chao; Zhang, Jia-Liang; Wang, De-Zhen; Ma, Teng-Cai

2010-05-01

115

[Influence of pre-analytical storage conditions on four plasma coagulation molecular markers measured using a STACIA automatic coagulation analyzer].  

PubMed

We investigated the effects of specimen storage conditions on the analysis of the coagulation molecular markers, soluble fibrin (SF), thrombin-antithrombin complex (TAT), thrombomodulin (TM) and tissue plasminogen activator inhibitor-1 complex (total PAI-1: tPAI). Marker levels were measured using a STACIA automatic coagulation analyzer. Among these four markers in blood from healthy subjects, only tPAI increased gradually with time, and the differences were especially marked when blood samples were stored at room temperature. Patient blood samples were stored for 4 hours under three different conditions: whole blood storage on ice, storage on ice after centrifugation, and refrigerated storage after centrifugation. Analytical results were compared between the three sets of samples. There were no significant differences in TAT or TM after 4 hours' storage under the different conditions. However, SF was decreased in several samples. In 11 of 14 samples with >20 microg/ml SF, SF levels were reduced by >10 microg/ml when whole blood without centrifugation was stored on ice. tPAI levels increased slightly after storage for 4 hours under all three conditions. These results suggest that centrifugation followed by refrigeration is the optimal storage method for blood samples when all four markers are to be measured simultaneously in the same sample. PMID:23427695

Yae, Masataka; Sueishi, Machiko; Mikami, Yoko; Kinoshita, Misae; Hirano, Sumiko; Nakamura, Kiyoko; Futata, Yuko; Kawashima, Hironobu; Ohkubo, Kumiko; Ishikura, Hiroyasu; Matsunaga, Akira

2012-12-01

116

Modelling of Argon-Carbon Dioxide Thermal Plasma  

NASA Astrophysics Data System (ADS)

A chemical kinetic model has been constructed to predict the pressure and gas and electron temperature dependency of the neutral and ionic species composition in Ar-CO_2 mixtures under thermal plasma conditions. Pure Ar and Ar-C models have also been constructed as a part of this investigation. The models include electron impact, thermal impact, ion-molecule, and recombination reactions as well as accounting for diffusion. Important metastable and excited states of species have been accounted for as well as the presence of neutral molecules, radicals, and atoms, positive and negatively charged atoms and molecular ions as well as electrons. All relevant electron temperature, gas temperature and pressure terms have been included, and primarily experimentally derived reaction rate constants were utilized. Electron and gas temperature dependent species concentrations were obtained under both thermodynamic equilibrium and non-equilibrium conditions for gas temperatures from 300 to 15000 K, electron temperatures from 300 to 20000 K, and pressures from 1 Torr to 15200 Torr. Percentage mixtures of C and CO_2 in Ar were varied between 0.1 and 40%. Results indicate that the neutral and excited species Ar, Ar*, Ar**, C, CO, Co_2, O, O_2 and O_3, positive ions Ar^+, Ar_sp {2}{+}, C^+, CArO^+, CO^+, CO_sp{2}{+}, CO_sp{4}{+}, C_2O_sp{2} {+}, O^+, O _sp{2}{+}, O _sp{4}{+}, and O _sp{5}{+} and negative ions CO_sp{3}{-}, CO_sp{4}{-}, O^-, O_sp{2 }{-}, and O_sp{3 }{-} and electrons are observed. Under thermodynamic equilibrium conditions, Ar, C, CO, CO _2, and O were found to be the dominant neutral species, C^+, CO_sp {4}{+}, O^+, and O_sp{2}{+} the dominant positive ions, and O^- and electrons the dominant negatively charged species under certain gas temperature ranges. The introduction of thermodynamic non-equilibrium conditions, changes in gas pressure, and percentage mixture of C or CO_2 were observed to have a significant influence on the temperature dependent concentrations of these species. The results were found to be in good agreement with previous experimental and theoretical results. Comparison of the present results with the results of the Saha equation seem to indicate that the simple Saha equation type approach may mispredict the plasma density of Ar, Ar-C, and Ar-CO _2 mixtures under thermal plasma conditions.

Beuthe, Thomas Gordon

117

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

SciTech Connect

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.

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

118

Kinetic simulations of argon dusty plasma afterglow including metastable atom kinetics  

SciTech Connect

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.

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

119

Two-dimensional self-consistent microwave argon plasma simulations with experimental verification  

NASA Astrophysics Data System (ADS)

Optical emission spectroscopy (OES), absorption measurements, and thermal energy rate analysis were used in tandem with numerical models to characterize microwave argon plasmas. A WAVEMAT (model MPDR-3135) microwave diamond deposition system was used to generate argon plasmas at 5 Torr. Three excited state number densities (4p, 5p, and 5d) were obtained from the OES measurements, and a fourth excited state number density (4s) was obtained from the absorption measurements. Further, power absorbed in the substrate was monitored. A self-consistent two-dimensional argon model coupled with an electromagnetic field model and a 25-level two-dimensional (2D)-collisional-radiative model (CRM) was developed and validated with the experimental measurements. The 2D model provides the gas and electron temperature distributions, and the electron, ion, and 4s state number densities, which are then iteratively fed into the electromagnetic and CRM models. Both the numerically predicted thermal energy rates and excited state densities agreed, within the experimental and numerical uncertainties, with the experimental results.

Li, Y.; Gordon, M. H.; Roe, L. A.; Hassouni, K.; Grotjohn, T.

2003-07-01

120

Study of non-thermal plasma jet with dielectric barrier configuration in nitrogen and argon  

NASA Astrophysics Data System (ADS)

Dielectric barrier discharge (DBD) is advantageous in generating non-thermal plasma at atmospheric pressure, as it avoids transition to thermal arc and dispenses with costly vacuum system. It has found useful applications in treating heat-sensitive materials such as plastics and living tissue. In this work, the discharge formed between the Pyrex glass layer and the ground electrode is extruded through a nozzle to form the non-thermal plasma jet. The DBD characteristics were investigated in terms of charge transferred and mean power dissipated per cycle when operated in nitrogen and argon at various flow rates and applied voltages. These characteristics were then correlated to the dimension of the plasma jet. The mean power dissipated in the DBD was below 7 W giving an efficiency of 17 %. The length of the plasma jet was greatly limited to below 1 cm due to the configuration of the DBD system and nozzle.

Choo, C. Y.; Chin, O. H.

2014-03-01

121

Effect of the electron energy distribution on total energy loss with argon in inductively coupled plasmas  

NASA Astrophysics Data System (ADS)

The total energy lost per electron-ion pair lost ?T is investigated with the electron energy distribution function (EEDF). The EEDFs are measured at various argon powers in RF inductively coupled plasma, and the EEDFs show a depleted distribution (a discontinuity occurring at the minimum argon excitation threshold energy level) with the bulk temperature and the tail temperature. The total energy loss per electron-ion pair lost ?T is calculated from a power balance model with the Maxwellian EEDFs and the depleted EEDFs and then compared with the measured ?T from the floating probe. It is concluded that the small population of the depleted high energy electrons dramatically increases the collisional energy loss, and the calculated ?T from the depleted EEDFs has a value that is similar to the measured ?T.

Kim, June Young; Kim, Young-Cheol; Kim, Yu-Sin; Chung, Chin-Wook

2015-01-01

122

Modelling of indium(I) iodide-argon low pressure plasma  

NASA Astrophysics Data System (ADS)

A new collisional-radiative model for a mercury-free low pressure plasma based on an indium(I) iodide-argon system is presented. The electron impact cross sections and rate coefficients for ionization, excitation and dissociation, as well as de-excitation, three-body recombination and dissociative recombination, of studied fillings have been calculated. Additionally, the coefficients for free and ambipolar diffusion were determined. The rate balance equations for individual generation and loss processes have been created. Densities of ions, electrons and neutral particles (ground or metastable state) are presented as a function of electron temperature for varied lamp parameters, such as argon buffer gas pressure and cold spot temperature (coldest point of discharge vessel). With the help of the presented model, the line emission coefficients of essential emission lines of indium for given electron temperatures and densities can be predicted.

Ögün, C. M.; Truong, W.; Kaiser, C.; Kling, R.; Heering, W.

2014-07-01

123

Kinetic modelling for an atmospheric pressure argon plasma jet in humid air  

NASA Astrophysics Data System (ADS)

A zero-dimensional, semi-empirical model is used to describe the plasma chemistry in an argon plasma jet flowing into humid air, mimicking the experimental conditions of a setup from the Eindhoven University of Technology. The model provides species density profiles as a function of the position in the plasma jet device and effluent. A reaction chemistry set for an argon/humid air mixture is developed, which considers 84 different species and 1880 reactions. Additionally, we present a reduced chemistry set, useful for higher level computational models. Calculated species density profiles along the plasma jet are shown and the chemical pathways are explained in detail. It is demonstrated that chemically reactive H, N, O and OH radicals are formed in large quantities after the nozzle exit and H2, O2(1?g), O3, H2O2, NO2, N2O, HNO2 and HNO3 are predominantly formed as ‘long living’ species. The simulations show that water clustering of positive ions is very important under these conditions. The influence of vibrational excitation on the calculated electron temperature is studied. Finally, the effect of varying gas temperature, flow speed, power density and air humidity on the chemistry is investigated.

Van Gaens, W.; Bogaerts, A.

2013-07-01

124

Polydiagnostic calibration performed on a low pressure surface wave sustained argon plasma  

NASA Astrophysics Data System (ADS)

The electron density and electron temperature of a low pressure surface wave sustained argon plasma have been determined using passive and active (laser) spectroscopic methods simultaneously. In this way the validity of the various techniques is established while the plasma properties are determined more precisely. The electron density, ne, is determined with Thomson scattering (TS), absolute continuum measurements, Stark broadening and an extrapolation of the atomic state distribution function (ASDF). The electron temperature, Te, is obtained using TS and absolute line intensity (ALI) measurements combined with a collisional-radiative (CR) model for argon. At an argon pressure of 15 mbar, the ne values obtained with TS and Stark broadening agree with each other within the error bars and are equal to (4 ± 0.5) × 1019 m-3, whereas the ne value (2 ± 0.5) × 1019 m-3 obtained from the continuum is about 30% lower. This suggests that the used formula and cross-section values for the continuum method have to be reconsidered. The electron density determined by means of extrapolation of the ASDF to the continuum is too high (~1020 m-3). This is most probably related to the fact that the plasma is strongly ionizing so that the extrapolation method is not justified. At 15 mbar, the Te values obtained with TS are equal to 13 400 ± 1100 K while the ALI/CR-model yields an electron temperature that is about 10% lower. It can be concluded that the passive results are in good or fair agreement with the active results. Therefore, the calibrated passive methods can be applied to other plasmas in a similar regime for which active diagnostic techniques cannot be used.

de Vries, N.; Palomares, J. M.; Iordanova, E. I.; van Veldhuizen, E. M.; van der Mullen, J. J. A. M.

2008-10-01

125

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

PubMed

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

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

2014-04-01

126

Detection of Fibrinogen and Coagulation Factor VIII in Plasma by a Quartz Crystal Microbalance Biosensor  

PubMed Central

A quartz crystal microbalance (QCM) biosensor with nanogram sensitivity has been constructed through a reasonable designing and biological processing of the piezoelectric quartz crystals. Due to its highly sensitivity, real time detection and low cost, the proposed QCM biosensor has a promising potential in blood coagulation research. In the current study, the QCM biosensor was used to determine the activated partial thromboplastin time (APTT) for 120 anticoagulated plasma specimens. A good linear relationship was found in a double-logarithmic plot of APTT versus fibrinogen concentration in the range of 1.58–6.30 g/L. For factor VIII, the detection range by the QCM biosensor is 0.0185–0.111 mg/L. The QCM biosensor results were compared with those obtained by commercial optical coagulometry and a good agreement (correlation coefficient is 0.949 for fibrinogen, and 0.948 for factor VIII) was reached. Furthermore, the QCM determination can be completed within 10 min. Our study suggested that the proposed QCM biosensor could provide for more convenient and time saving operations, which may be useful in clinical situations for rapid monitoring of anticoagulant therapy using small volume (20 ?L) plasma specimens. PMID:23708275

Yao, Chunyan; Qu, Ling; Fu, Weiling

2013-01-01

127

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

128

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

SciTech Connect

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.

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

129

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

SciTech Connect

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.

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

130

Spectroscopic study of atmospheric pressure 915 MHz microwave plasma at high argon flow rate  

NASA Astrophysics Data System (ADS)

In this paper results of optical emission spectroscopic (OES) study of atmospheric pressure microwave 915 MHz argon plasma are presented. The plasma was generated in microwave plasma source (MPS) cavity-resonant type. The aim of research was determination of electron excitation temperature Texc gas temperature Tg and electron number density ne. All experimental tests were performed with a gas flow rate of 100 and 200 l/min and absorbed microwave power PA from 0.25 to 0.9 kW. The emission spectra at the range of 300 - 600 nm were recorded. Boltzmann plot method for argon 5p - 4s and 5d - 4p transition lines allowed to determine Texc at level of 7000 K. Gas temperature was determined by comparing the measured and simulated spectra using LIFBASE program and by analyzing intensities of two groups of unresolved rotational lines of the OH band. Gas temperature ranged 600 - 800 K. The electron number density was determined using the method based on the Stark broadening of hydrogen H? line. The measured ne rang ed 2 × 1015 - 3.5×1015 cm-3, depending on the absorbed microwave power. The described MPS works very stable with various working gases at high flow rates, that makes it an attractive tool for different gas processing.

Miotk, R.; Hrycak, B.; Jasinski, M.; Mizeraczyk, J.

2012-12-01

131

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

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

132

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

SciTech Connect

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.

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

2008-06-15

133

Effects of UV light irradiation on propane in an argon plasma  

SciTech Connect

It has been shown that propane conversion into acetylene, by propane cracking in an argon plasma, is increased when the reaction site is irradiated with UV light in the range 220-400nm. The reactions were carried out between 4500 and 6400 K. A model is outlined following which the propane conversion increase at 6400 K (40%) is tied up to energy absorption by acetylene in the lower wavelengths range (220-250nm). Also, a combined adsorption-photochemical process, related to precursors and submicron carbon particles, could be responsible for the yield increase observed at 5400 K (45%), around 365.0nm.

Meubus, P.

1986-06-01

134

Spectroscopic study of a long high-electron-density argon plasma column generated at atmospheric pressure  

Microsoft Academic Search

A stable plasma column is generated in a quartz tube using a pair of\\u000a hollow electrodes driven by a sinusoidal power supply of 45 kHz at\\u000a atmospheric pressure in argon. Two distinct operating modes (low-current\\u000a and high-current modes) are identified through observing its discharge\\u000a phenomena, measuring its electrical characteristics, and determining the\\u000a gas temperatures by spectroscopic diagnosis of Q branch

Shou-Zhe Li; Wen-Tong Huang; Dezhen Wang

2010-01-01

135

Thermodynamic properties and transport coefficients of arc lamp plasmas: argon, krypton and xenon  

NASA Astrophysics Data System (ADS)

Calculated values of the density, specific heat, enthalpy, viscosity, thermal conductivity and electrical conductivity of thermal plasmas formed from three gases used in arc lamps, krypton, argon and xenon, are presented. The calculations, which assume local thermodynamic equilibrium, were performed for pressures from 1 to 100 atm and for the temperature range 300-30?000 K. The results were compared with those of previously published studies. Some discrepancies were found for krypton and xenon; these are attributed to the improved values of the collision integrals used here in calculating the transport coefficients.

Murphy, Anthony B.; Tam, Eugene

2014-07-01

136

Plasma waves generated in the ionosphere by an argon ion beam  

NASA Astrophysics Data System (ADS)

Two argon ion generators were operated during a sounding rocket flight from Sondre Stromfjord, Greenland, on February 10, 1985. One generator emitted an ion beam perpendicular to the magnetic field and the other a beam parallel to the field. The ion generators were on a subpayload that was separated from the main payload early in the flight. Plasma waves were observed during most of the first seven operations of each beam. Helium and oxygen cyclotron harmonics were observed in early perpendicular beam operations. The parallel beam waves were line emissions, some at approximate multiples of the hydrogen cyclotron frequency and near the lower hybrid frequency.

Cahill, L. J., Jr.; Erlandson, R. E.; Arnoldy, R. L.; Pollock, C. J.

137

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

NASA Technical Reports Server (NTRS)

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.

Cambier, Jean-Luc

1991-01-01

138

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

139

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

SciTech Connect

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.

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

140

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

SciTech Connect

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.

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

141

Characteristics of emissive spectrum and the removal of nitric oxide in N2/02/NO plasma with argon additive.  

PubMed

Although the approach using non-thermal plasma (NTP) for deNOx has been studied for over 15 years, how to achieve higher removal efficiency with lower cost is still a barrier for its industrial application. In order to investigate the impact of the argon additive on electron density, energy and nitric oxide reduction process in plasma, the spectrum of the dielectric barrier discharge at atmospheric pressure in a coaxial reactor was measured using the monochromater with high resolution. The comparative experiments for NO reduction were carried out simultaneously in N2/O2/NO plasma stream with and without argon, respectively. The nitrogen molecular spectrum which is attributed to the energy level transition (C3pi(u)-->B3pi(g)) was compared in the wavelength range 300-480 nm and the electron density and temperature were determined based on the relative intensities and Stark broadening width of spectral lines. The spectrum results indicated that the argon additive could enhance the intensity of emissive spectrum of plasma, thus the electron concentration as well as the energy was increased, and finally prompted the ionization rate to produce active N, O and O3. The results of NO reduction showed that NO conversion efficiency increased in the range of 10%-30% with 5% addition of argon in stream comparing with the condition without argon additive. This study will play a positive role in the industrial application of dielectric barrier discharge deNOx reactor. PMID:19803084

Lin, Wenfeng; Zhang, Bin; Hou, Wenhui; Li, Dawei; Yang, Hongmin

2009-01-01

142

Atmospheric pressure streamer follows the turbulent argon air boundary in a MHz argon plasma jet investigated by OH-tracer PLIF spectroscopy  

NASA Astrophysics Data System (ADS)

An open question in the research of the dynamics of non-equilibrium cold atmospheric pressure plasma jets is the influence of ambient species on streamer propagation pathways. In the present work, by means of planar laser-induced fluorescence (PLIF), an atmospheric pressure argon plasma jet is investigated in a laminar and turbulent gas flow regime. The flow pattern is investigated with plasma on and plasma off. It is shown that in turbulent mode, the streamer path changes according to the flow pattern changes and the resulting changes in air abundance. From a comparison of an analytical diffusion calculation and LIF measurements, the air impurity boundary is determined. Most importantly, the origin of the streamer pathway is investigated in detail, by recording the flow pattern from OH-PLIF measurements and simultaneously measuring the streamer path by an overlay technique through emission measurements. It is shown that the streamer path is correlated to the turbulent flow pattern.

Iseni, S.; Schmidt-Bleker, A.; Winter, J.; Weltmann, K.-D.; Reuter, S.

2014-04-01

143

Modification of tapioca starch by non-chemical route using jet atmospheric argon plasma.  

PubMed

Non-chemical modification of tapioca starch was investigated using jet atmospheric argon plasma treatment. Two forms of starch slurry, i.e. granular starch (G) and cooked starch (C), were jet-treated by argon plasma generated by supplying input power of 50 W (denoted as G50 and C50 samples) and 100 W (denoted as G100 and C100 samples) for 5 min. Physical, rheological, and structural characteristics of the modified starch were investigated. The G50 and C100 samples had lower paste clarity but higher thermal stability and performed stronger gels (G50 only) compared to their control counterparts. On the other hand, the analyzed properties of the G100 and C50 samples showed the opposite trend. FTIR and (1)H NMR results revealed that the relative areas of COC and OH peaks were changed after the treatment. Cross-linking reaction seemed to predominantly take place for the G50 and C100 samples, whereas depolymerization predominated for the G100 and C50 samples. PMID:24507348

Wongsagonsup, Rungtiwa; Deeyai, Panakamol; Chaiwat, Weerawut; Horrungsiwat, Sawanee; Leejariensuk, Kesini; Suphantharika, Manop; Fuongfuchat, Asira; Dangtip, Somsak

2014-02-15

144

Energy loss of argon in a laser-generated carbon plasma  

SciTech Connect

The experimental data presented in this paper address the energy loss determination for argon at 4 MeV/u projectile energy in laser-generated carbon plasma covering a huge parameter range in density and temperature. Furthermore, a consistent theoretical description of the projectile charge state evolution via a Monte Carlo code is combined with an improved version of the CasP code that allows us to calculate the contributions to the stopping power of bound and free electrons for each projectile charge state. This approach gets rid of any effective charge description of the stopping power. Comparison of experimental data and theoretical results allows us to judge the influence of different plasma parameters.

Frank, A.; Harres, K.; Hoffmann, D. H. H.; Knobloch-Maas, R.; Nuernberg, F.; Pelka, A.; Schaumann, G.; Schoekel, A.; Schollmeier, M.; Schumacher, D.; Schuetrumpf, J.; Roth, M. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt (Germany); Blazevic, A.; Hessling, T. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt (Germany); Grande, P. L. [Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, Porto Alegre 91501-970, RS (Brazil); Kuznetsov, P. G.; Vatulin, V. V.; Vinokurov, O. A. [RFNC-VNIIEF, Sarov, Nizhny Novgorod Region 607190 (Russian Federation); Schiwietz, G. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Glienicker Strasse 100, D-14109 Berlin (Germany)

2010-02-15

145

Deposition of a-SiC:H using organosilanes in an argon/hydrogen plasma  

SciTech Connect

Selected organosilanes were examined as precursors for the deposition of amorphous hydrogenated silicon carbide in an argon/hydrogen plasma. Effect of process variables on the quality of the films was established by means of FTIR, Auger spectroscopy, XPS, XRD, chemical analysis, and weight losses upon pyrolysis. For a given power level there is a limiting feeding rate of the precursor under which operation of the system is dominated by thermodynamics and leads to high quality silicon carbide films that are nearly stoichiometric and low in hydrogen. Beyond that limit, carbosilane polymer formation and excessive hydrogen incorporation takes place. The hydrogen content of the plasma affects the deposition rate and the hydrogen content of the film. In the thermodynamically dominated regime the nature of the precursor has no effect on the quality of the film, it affects only the relative utilization efficiency.

Maya, L.

1993-12-01

146

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

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

147

Generation of Cold Argon Plasma Jet at the End of Flexible Plastic Tube  

E-print Network

This brief communication reports a new method for generation of cold atmospheric pressure plasma jet at the downstream end of a flexible plastic tube. The device consists of a small chamber where dielectric barrier discharge (DBD) is ignited in Argon. The discharge is driven by a conventional low frequency AC power supply. The exit of DBD reactor is connected to a commercial flexible plastic tube (up to 4 meters long) with a thin floating Cu wire inside. Under certain conditions an Ar plasma jet can be extracted from the downstream tube end and there is no discharge inside the plastic tube. The jet obtained by this method is cold enough to be put in direct contact with human skin without electric shock and can be used for medical treatment and decontamination.

Kostov, Konstantin G; Prysiazhnyi, Vadym

2014-01-01

148

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

SciTech Connect

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.

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

1986-01-01

149

Atomic data generation and collisional radiative modeling of argon II, argon III, and neon I for laboratory and astrophysical plasmas  

NASA Astrophysics Data System (ADS)

Accurate knowledge of atomic processes plays a key role in modeling the emission in laboratory as well as in astrophysical plasmas. These processes are included in a collisional-radiative model and the results are compared with experimental measurements for Ar and Ne ions from the ASTRAL (Auburn Steady sTate Research fAciLity) experiment. The accuracy of our model depends upon the quality of the atomic data we use. Atomic data for near neutral systems present a challenge due to the low accuracy of perturbative methods for these systems. In order to improve our model we rely on non-perturbative methods such as R - Matrix and RMPS ( R -Matrix with Pseudo-States) to include correlation in the collision cross-sections. In the case of Ar + we compared R -Matrix electron-impact excitation data against the results from a new RMPS calculation. The aim was to assess the effects of continuum-coupling effects on the atomic data and the resulting spectrum. We do our spectral modeling using the ADAS suite of codes. Our collisional-radiative formalism assumes that the excited levels are in quasi- static equilibrium with the ground and metastable populations. In our model we allow for N e and T e variation along the line of sight by fitting our densities and temperature profiles with those measured within the experiment. The best results so far have been obtained by the fitting of the experimental temperature and density profiles with Gaussian and polynomial distribution functions. The line of sight effects were found to have a significant effect on the emission modeling. The relative emission rates were measured in the ASTRAL helicon plasma source. A spectrometer which features a 0.33 m Criss-Cross Scanning monochromator and a CCD camera is used for this study. ASTRAL produces bright intense Ar and Ne plasmas with n e = 10 11 to 10 13 cm -3 and T e = 2 to 10 eV. A series of 7 large coils produce an axial magnetic field up to 1.3 kGauss. A fractional helix antenna is used to introduce RF power up to 2 kWatt. Two RF compensated Langmuir probes are used to measure T e and N e . In a series of experiment Ar II, Ar III, and Ne transitions are monitored as a function of T e , while Ne is kept nearly constant. Observations revealed that T e is by far the most significant parameter affecting the emission rate coefficients, thus confirming our predictions. The spectroscopy measurements are compared with those from our spectral modeling which in turn help us to compare the effectiveness of the new atomic data calculations with those from other calculations. We performed a new R -Matrix calculation for Ar 2+ . Emission from Ar 2+ is seen in planetary nebulae, in H II regions, and from laboratory plasmas. Our calculation improved upon existing electron-impact excitation data for the 3p 4 configuration of Ar 2+ and calculated new data for the excited levels. Electron-impact excitation collision strengths were calculated using the R - Matrix intermediate-coupling (IC) frame-transformation method and the R -Matrix Breit-Pauli method. Excitation cross-sections are calculated between all levels of the configurations 3s 2 3p 4 , 3s 3p 5 , 3p 6 , 3p 5 3d, and 3s 2 3p 3 nl (3d <= nl <= 5s). Maxwellian effective collision strengths are generated from the collision strength data. Good agreement is found in the collision strengths calculated using the two R -Matrix methods. The effects of the new data on line ratio diagnostics were studied. The collision strengths are compared with literature values for transitions within the 3s 2 3p 4 configuration. The new data has a small effect on T e values obtained from the I (l7135Å + l7751Å)/ I (l5192Å) line ratio, and a larger effect on the N e values obtained from the I (l7135Å)/ I (l9m m ) line ratio. The final effective collision strength data is archived online. Neon as well as Argon is a species of current interest in fusion TOKAMAK studies. It is used for radiative cooling of the divertor region and for disruption mitigation. It could also be useful as a spectral diagnostic if better atomic data w

Munoz Burgos, Jorge Manuel

150

Argon plasma vs. air plasma: Characteriazation and interaction with biological systems  

Microsoft Academic Search

Recently, there has been enormous progress in plasma medicine. New groups have joined this area of research. New plasma devices have been developed and tested for biomedical applications. The difference in plasma production methods and composition of input gases does not allow to directly compare plasmas produced by various devices and predict their effect on biological systems.

Tetyana Nosenko; Tetsuji Shimizu; Julia Zimmermann; Bernd Steffes; Gregor E. Morfill

2010-01-01

151

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

SciTech Connect

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..

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

2008-01-01

152

Antiphospholipid antibodies accelerate plasma coagulation by inhibiting annexin-V binding to phospholipids: a "lupus procoagulant" phenomenon.  

PubMed

The antiphospholipid syndrome is a thrombophilic condition marked by antibodies that recognize anionic phospholipid-protein cofactor complexes. We recently reported that exposure to IgG fractions from antiphospholipid patients reduces the level of annexin-V, a phospholipid-binding anticoagulant protein, on cultured trophoblasts and endothelial cells and accelerates coagulation of plasma exposed to these cells. Therefore, we asked whether antiphospholipid antibodies might directly reduce annexin-V binding to noncellular phospholipid substrates. Using ellipsometry, we found that antiphospholipid IgGs reduce the quantity of annexin-V bound to phospholipid bilayers; this reduction is dependent on the presence of beta2-glycoprotein I. Also, exposure to plasmas containing antiphospholipid antibodies reduces annexin-V binding to phosphatidyl serine-coated microtiter plates, frozen thawed washed platelets, activated partial thromboplastin time (aPTT) reagent and prothrombin time reagent and reduces the anticoagulant effect of the protein. These studies show that antiphospholipid antibodies interfere with the binding of annexin-V to anionic phospholipid and with its anticoagulant activity. This acceleration of coagulation, due to reduced binding of annexin V, stands in marked contrast to the "lupus anticoagulant effect" previously described in these patients. These results are the first direct demonstration of the displacement of annexin-V and the consequent acceleration of coagulation on noncellular phospholipid surfaces by antiphospholipid antibodies. PMID:9716593

Rand, J H; Wu, X X; Andree, H A; Ross, J B; Rusinova, E; Gascon-Lema, M G; Calandri, C; Harpel, P C

1998-09-01

153

Effects of MASP-1 of the Complement System on Activation of Coagulation Factors and Plasma Clot Formation  

PubMed Central

Background Numerous interactions between the coagulation and complement systems have been shown. Recently, links between coagulation and mannan-binding lectin-associated serine protease-1 (MASP-1) of the complement lectin pathway have been proposed. Our aim was to investigate MASP-1 activation of factor XIII (FXIII), fibrinogen, prothrombin, and thrombin-activatable fibrinolysis inhibitor (TAFI) in plasma-based systems, and to analyse effects of MASP-1 on plasma clot formation, structure and lysis. Methodology/Principal Findings We used a FXIII incorporation assay and specific assays to measure the activation products prothrombin fragment F1+2, fibrinopeptide A (FPA), and activated TAFI (TAFIa). Clot formation and lysis were assessed by turbidimetric assay. Clot structure was studied by scanning electron microscopy. MASP-1 activated FXIII and, contrary to thrombin, induced FXIII activity faster in the Val34 than the Leu34 variant. MASP-1-dependent generation of F1+2, FPA and TAFIa showed a dose-dependent response in normal citrated plasma (NCP), albeit MASP-1 was much less efficient than FXa or thrombin. MASP-1 activation of prothrombin and TAFI cleavage were confirmed in purified systems. No FPA generation was observed in prothrombin-depleted plasma. MASP-1 induced clot formation in NCP, affected clot structure, and prolonged clot lysis. Conclusions/Significance We show that MASP-1 interacts with plasma clot formation on different levels and influences fibrin structure. Although MASP-1-induced fibrin formation is thrombin-dependent, MASP-1 directly activates prothrombin, FXIII and TAFI. We suggest that MASP-1, in concerted action with other complement and coagulation proteins, may play a role in fibrin clot formation. PMID:22536427

Hess, Katharina; Ajjan, Ramzi; Phoenix, Fladia; Dobó, József; Gál, Péter; Schroeder, Verena

2012-01-01

154

Irradiation of silver and agar/silver nanoparticles with argon, oxygen glow discharge plasma, and mercury lamp.  

PubMed

The irradiation effect of argon, oxygen glow discharge plasma, and mercury lamp on silver and agar/silver nanoparticle samples is studied. The irradiation time dependence of the synthesized silver and agar/silver nanoparticle absorption spectra and their antibacterial effect are studied and compared. In the agar/silver nanoparticle sample, as the irradiation time of argon glow discharge plasma or mercury lamp increases, the peak intensity and the full width at half maximum, FWHM, of the surface plasmon resonance absorption band is increased, however a decrease of the peak intensity with oxygen glow plasma has been observed. In the silver nanoparticle sample, as the irradiation time of argon, oxygen glow discharge plasma or mercury lamp increases, the peak intensity of the surface plasmon resonance absorption band is increased, however, there is no significant change in the FWHM of the surface plasmon resonance absorption band. The SEM results for both samples showed nanoparticle formation with mean size about 50 nm and 40 nm respectively. Throughout the irradiation time with the argon, oxygen glow discharge plasma or mercury lamp, the antibacterial activity of several kinds of Gram-positive and Gram-negative bacteria has been examined. PMID:25184109

Ahmad, Mahmoud M; Abdel-Wahab, Essam A; El-Maaref, A A; Rawway, Mohammed; Shaaban, Essam R

2014-01-01

155

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

SciTech Connect

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.

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

156

Determining the effect of freezing on coagulation testing: comparison of results between fresh and once frozen-thawed plasma.  

PubMed

The accuracy of the results from coagulation testing can be affected by numerous preanalytic and analytic variables including the stability of the citrated sample at room temperature. Samples not tested within 2-4?h of collection should be processed and frozen for later analysis. As limited data exist about the impact of freezing samples on coagulation testing, we sought to evaluate the effect of freezing on coagulation testing. Plasma samples into 3.2% sodium citrate tubes, centrifuged to yield platelet-poor plasma, were evaluated for prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, D-dimer, antithrombin (AT) activity, factors V, VII, VIII, IX, lupus anticoagulant and anti-Xa measurements for both unfractionated and low-molecular-weight heparins. Samples were then frozen at -70°C for at least 1 week and testing was repeated using the same lot of material. All tests strongly correlated (R?>?0.85) between fresh and frozen sample results. Using paired t test analysis, significant differences between fresh and frozen tested plasma existed for PT, APTT, factors V, VIII and AT. Significant differences existed between fresh and frozen lupus anticoagulant ratios (lupus anticoagulant screen but not lupus anticoagulant confirm), and single centrifugation process underestimated the presence of lupus anticoagulant as compared to double centrifugation processing. Freezing significantly affects the results for PT, APTT, factors V and VIII activity, and AT activity, although these differences were not considered to be clinically significant. Double centrifugation is required for accurate lupus anticoagulant testing, regardless of whether platelet-poor plasma is achieved with single centrifugation. PMID:25202883

Gosselin, Robert C; Dwyre, Denis W

2015-01-01

157

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

SciTech Connect

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 H{sub 2}O-Ar mixture flow rate of 1.7 standard liter per minute (slm). With an increase in the H{sub 2}O/Ar ratio from 0.0 to 1.9%, the plasma jet column length decreased from 11 mm to 4 mm, and the plasma jet became unstable when the ratio was higher than 1.9%; elevation of plasma gas temperature up to 330 K was observed in the plasma temperature range of 420-910 K. Optical emission spectroscopy showed that the dominant plasma emissions changed from N{sub 2} in the pure Ar plasma jet to OH with the addition of water vapor, and simulations of emission spectra suggested non-Boltzmann distribution of the rotational levels in the OH A-state (v'=0). Spatially resolved absolute OH number densities along the plasma jet axis were measured using UV cavity ringdown spectroscopy of the OH (A-X) (0-0) band in the H{sub 2}O/Ar ratio range of 0.0-1.9%. The highest OH number density is consistently located in the vicinity of the plasma jet tip, regardless of the H{sub 2}O/Ar ratio. OH number density in the post-tip region follows approximately an exponential decay along the jet axis with the fastest decay constant of 3.0 mm in the H{sub 2}O/Ar ratio of 1.5%. Given the low gas temperature of 420-910 K and low electron temperature of 0.5-5 eV along the jet axis, formation of the OH radical is predominantly due to electron impact induced dissociation of H{sub 2}O and dissociative recombination of H{sub 2}O{sup +} resulting from the Penning ionization process.

Srivastava, Nimisha; Wang Chuji [Department of Physics and Astronomy and the Energy Institute, Mississippi State University, Mississippi State, Mississippi 39762 (United States)

2011-09-01

158

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

E-print Network

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

Harilal, S. S.

159

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

SciTech Connect

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.

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

1982-10-01

160

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

Microsoft Academic Search

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.

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

1982-01-01

161

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

162

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

SciTech Connect

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.

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

163

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

SciTech Connect

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.

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

164

Argon Plasma-Induced Graft Polymerization of PEGMA on Chitosan Membrane Surface for Cell Adhesion Improvement  

NASA Astrophysics Data System (ADS)

For its biocompatibility and biodegradability, chitosan has had considerable attention for biomedical applications in recent years. In this paper, polymerization of poly (ethylene glycol) methyl ether methacrylate (PEGMA) was grafted onto chitosan membrane surface through argon plasma-induced graft polymerization. The surface properties after modification were characterized by contact angle measurement, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), respectively. The results indicated that PEGMA can be grafted successfully onto chitosan membrane surface. The surface hydrophilicity and free energy were improved and the surface roughness increased after modification. The adhesion of a human corneal epithelial cell (HCEC) on chitosan membrane surface was enhanced due to improvement of surface free energy and roughness.

Yin, Shiheng; Ren, Li; Wang, Yingjun

2013-10-01

165

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

SciTech Connect

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.

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

166

Surface free energy analysis for bipolar pulsed argon plasma treated polymer films  

NASA Astrophysics Data System (ADS)

The effect of low energy (300 eV) argon plasma treatment on the morphology of polycarbonate was studied by means of contact angle measurement, X-ray photoelectron spectroscopy (XPS), Vickers' micro hardness indentation and atomic force microscopy (AFM). The surface free energy (SFE) changes from 38.5 mJ/m2 to 74.9 mJ/m2 on increasing the treatment time and the corresponding contact angle was changed from 63° to 17°, which shows the enhancement in surface adhesion. The XPS analysis shows the increase of the C-O and C=O functional groups upon treatment. The Vickers' micro hardness was studied in the load range 10-500 gf. The micro hardness of the film increases with the treatment time. Atomic force microscopy (AFM) reveals that average surface roughness increases from 7.0 nm to 27.2 nm as treatment time increases.

Pelagade, S.; Singh, N. L.; Shah, Sejal; Qureshi, Anjum; Rane, R. S.; Mukherjee, S.; Deshpande, U. P.; Ganesan, V.; Shripathi, T.

2010-02-01

167

Application of a hybrid collisional radiative model to recombining argon plasmas  

NASA Astrophysics Data System (ADS)

A collisional radiative model, in which a hybrid cut-off technique is used, is applied to recombining plasmas to study the atomic state distribution (ASDF) and the recombination coefficient. Computations of the ASDF using semi-empirical rate coefficients of Vriens and Smeets (V-S) and Drawin (D) are compared with experimental values measured at various positions in a free expanding argon arc jet. Apart from the shock position, where the calculated results are too low, the model calculations are higher than the experimental results. The volumetric recombination coefficient has a Te exp -4 and a Te exp -4.8 dependence when semiempirical rate coefficients of, respectively, V-S and D are used. The differences between the models based on the rate coefficients of V-S and D indicate that the recombination flow is sensitive to the low temperature behavior of the rate coefficients.

Benoy, D. A.; van der Mullen, J. A. M.; van de Sanden, M. C. M.; van der Sijde, B.; Schram, D. C.

1993-02-01

168

The Mechanisms of Coagulation.  

ERIC Educational Resources Information Center

Several topics such as heart disease, strokes, biochemical reactions, blood components, and genetics can be related to blood clotting. Introduces a simple, safe and inexpensive hands-on demonstration using bovine (cattle) blood plasma of normal and abnormal coagulation. (ZWH)

Kurtz, Richard; Jesty, Jolyon

1994-01-01

169

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

SciTech Connect

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.

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

170

Correlations between plasma variables and the deposition process of Si films from chlorosilanes in low pressure RF plasma of argon and hydrogen  

NASA Technical Reports Server (NTRS)

The dissociation of chlorosilanes to silicon and its deposition on a solid substrate in a RF plasma of mixtures of argon and hydrogen were investigated as a function of the macrovariables of the plasma. The dissociation mechanism of chlorosilanes and HCl as well as the formation of Si in the plasma state were studied by sampling the plasma with a quadrupole mass spectrometer. Macrovariables such as pressure, net RF power input and locations in the plasma reactor strongly influence the kinetics of dissociation. The deposition process of microcrystalline silicon films and its chlorine contamination were correlated to the dissociation mechanism of chlorosilanes and HCl.

Avni, R.; Carmi, U.; Grill, A.; Manory, R.; Grossman, E.

1984-01-01

171

Spatially resolved measurement of hydroxyl radical (OH) concentration in an argon RF plasma jet by planar laser-induced fluorescence  

NASA Astrophysics Data System (ADS)

A spatially resolved two-dimensional quantitative measurement of OH concentration in an effluent of a radio-frequency-driven atmospheric pressure plasma jet ignited in argon is presented. The measurement is supported by a gas dynamics model which gives detailed information about the spatially resolved gas composition and temperature. The volume in which the OH radicals were found and partially also the total amount of OH radicals increase with the argon flow rate, up to a value for which the flow becomes turbulent. In the turbulent regime, both the emission from the jet and the OH concentration are confined to a smaller volume. The maximum concentration of about 5.4 × 1021 m-3 is reached at the tip of the visible discharge at the flow rate of 0.6 slm and high driving powers. An increase in hydroxyl concentration due to admixing of humid ambient air to the argon flow was observed.

Vorá?, J.; Obrusník, A.; Procházka, V.; Dvo?ák, P.; Talába, M.

2014-04-01

172

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

PubMed

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

Traba, Christian; Liang, Jun F

2015-01-01

173

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

Microsoft Academic Search

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

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

174

Ultra-violet recombination continuum electron temperature measurements in a non-equilibrium atmospheric argon plasma  

NASA Astrophysics Data System (ADS)

Emission measurements of temperature and electron density have been made downstream of a 50 kW induction plasma torch at temperatures and electron densities ranging between 6000 K and 8500 K and 10 to the 20th and 10 to the 21st/cu cm, respectively. Absolute and relative atomic line intensities, and absolute recombination continuum in both the visible and the UV were separately interpreted in order to characterize a recombining atmospheric argon plasma. Continuum measurements made in the UV at 270 nm were used to directly determine the kinetic electron temperature, independent of a Boltzmann equilibrium, assuming only that the electron velocity distribution is Maxwellian. The data indicate that a nonequilibrium condition exists in which the bound-excited and free electrons are nearly in mutual equilibrium down to the 4P level for electron densities as low as 2 x 10 to the 20th/cu m but that both are overpopulated with respect to the ground state due to finite recombination rates.

Gordon, M. H.; Kruger, C. H.

1991-06-01

175

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

NASA Astrophysics Data System (ADS)

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.

Küllig, C.; Wegner, Th; Meichsner, J.

2015-02-01

176

Electron Temperature and Ion Beam Scaling with RF Input Power in an Argon Helicon Plasma  

NASA Astrophysics Data System (ADS)

A flowing argon helicon plasma is formed in a 10 cm diameter, 1.5 m long Pyrex chamber with an axial magnetic field in nozzle or flat configuration, variable up to 1 kG in the source region. A new expansion chamber has been constructed and initial laser induced fluorescence (LIF) results including ion velocities and temperatures are presented. Microwave interferometry (105 GHz), collisional radiative spectroscopic codes and diamagnetic loops are used to measure electron density and temperature during pulsed (5 ms) RF operation. Calculated variation of the RF frequency (from 12 MHz to 15 MHz) during the pulse allows for low (<5%) reflected powers during the gas breakdown and the approach to and formation of the steady state plasma. The scaling of electron temperature with RF power is also examined for high (>3 kW) RF powers. The effect of different flow rates, magnetic field expansion variation and pressures are measured to observe the variation of the ion distribution function via LIF and the axial variation of acceleration due to neutral depletion. Possible double layer creation and sustainment in the downstream (relative to the RF antenna) transition to the expansion chamber is also examined at low flow rates and high RF powers.

Wiebold, Matt; Scharer, John; Sung, Yung-Ta

2010-11-01

177

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

178

Dependence of Plasma Focus Argon Soft X-Ray Yield on Storage Energy, Total and Pinch Currents  

NASA Astrophysics Data System (ADS)

Numerical experiments are carried out systematically to determine the argon soft X-Ray yield Ysxr for optimized argon plasma focus with storage energy E0 from 1 kJ to 1 MJ. The ratio c = b/a, of outer to inner radii; and the operating voltage V0 are kept constant. E0 is varied by changing the capacitance C0. These numerical experiments were investigated on argon plasma focus at different operational gas pressures (0.41, 0.75, 1, 1.5, 2.5 and 3 Torr) for two different values of static inductance L0 (270 and 10 nH). Scaling laws on argon soft X-Ray yield, in terms of storage energies E0, peak discharge current Ipeak and focus pinch current Ipinch were found. It was found that the argon X-ray yields scale well with for the high inductance (270 nH) and for the low inductance (10 nH), (where yields are in joules and current in kilo amperes). While the soft X-ray yield scaling laws in terms of storage energies were found to be as at energies in the 1-100 kJ region. The scaling `drops' as E0 is increased, and Ysxr scales as at high energies towards 1 MJ for 10 nH at argon gas pressure of 1 Torr. The optimum efficiencies for SXR yield were found to be 0.00077% with a capacitor bank energy of 112.5 kJ for high inductance (270 nH) and 0.005% with a capacitor bank energy of 4.5 kJ for low inductance (10 nH). Therefore for larger devices, it may be necessary to operate at a higher voltage and use higher driver impedance to ensure increasing X-ray yield efficiency beyond the optimum values. As storage energy is changed the required electrode geometry for optimum yield is obtained and the resultant plasma pinch parameters are found. Required values of axial speed for argon soft X-ray emission were found to be in the range 11-14 cm/?s.

Akel, M.; Lee, S.

2012-04-01

179

Influence of cysteine proteinase inhibitors on platelet and plasma components of blood coagulation system  

Microsoft Academic Search

Factor XIIIa plays an important role in stabilization of formed fibrin clot during blood coagulation. Recent studies proved\\u000a that factor XIIIa affects formation of coated platelets, which are highly procoagulant and characterized by a high level of\\u000a alpha-granular proteins on their surface and expose surface phosphatidylserine after platelet activation. The ability of newly\\u000a found cysteine proteinase inhibitors (CPIs) from plants

Ya. N. Kotova; E. A. Kostanova; M. A. Rozenfel’d; E. I. Sinauridze; M. A. Panteleev; F. I. Ataullakhanov

2009-01-01

180

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

SciTech Connect

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.

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

2011-06-01

181

Excitation dynamics of a kHz driven micro-structured plasma channel device operated in argon  

Microsoft Academic Search

The excitation dynamics of a micro-structured plasma channel device with an inverted equilateral triangular cross-section are investigated. This device is operated in argon close to atmospheric pressure with an ac voltage. It is characterized by means of electrical measurements and optical emission spectroscopy. One emission phase is observed in each half-cycle of the applied voltage waveform. Each shows self-pulsing of

A. Greb; H. Boettner; J. Winter; V. Schulz-von der Gathen

2011-01-01

182

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

SciTech Connect

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.

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

183

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

SciTech Connect

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.

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

184

Discharge characteristics of an atmospheric-pressure argon plasma column generated with a single-electrode configuration  

NASA Astrophysics Data System (ADS)

An atmospheric-pressure argon discharge plasma column is generated by making use of a single-electrode configuration with the power supply operating at a frequency of 45 kHz. It is observed that corona, glowlike plume, and filamentary discharges evolve individually with increasing applied voltage. It is in the filamentary state with average electron density of order 1012 cm-3 that plasma column grows up in the tube with increasing applied voltage. Its discharge characteristics are determined by measuring electrical parameters (voltage, conduction current, and average absorbed power) and optical emission spectroscopy.

Li, Shou-Zhe; Huang, Wen-Tong; Zhang, Jialiang; Wang, Dezhen

2009-07-01

185

Surface modification by argon plasma treatment improves antioxidant defense ability of CHO-k1 cells on titanium surfaces.  

PubMed

Titanium is one of the most used materials in implants and changes in its surface can modify the cellular functional response to better implant fixation. An argon plasma treatment generates a surface with improved mechanical proprieties without modifying its chemical composition. Oxidative stress induced by biomaterials is considered one of the major causes of implant failure and studies in this field are fundamental to evaluate the biocompatibility of a new material. Therefore, in this work, induction of oxidative stress by titanium surfaces subjected to plasma treatment (PTTS) was evaluated. The viability of CHO-k1 cells was higher on PTTS discs. Cells grown on titanium surfaces are subjected to intracellular oxidative stress. Titanium discs subjected to the plasma treatment induced less oxidative stress than the untreated ones, which resulted in improved cellular survival. These were associated with improved cellular antioxidant response in Plasma Treated Titanium Surface (PTTS). Furthermore, a decrease in protein and DNA oxidative damage was observed on cells grown on the roughed surface when compared to the smooth one. In conclusion, our data suggest that the treatment of titanium with argon plasma may improve its biocompatible, thus improving its performance as implants or as a scaffold in tissue engineering. PMID:24296152

de Queiroz, Jana Dara Freires; Leal, Angélica Maria de Sousa; Terada, Maysa; Agnez-Lima, Lucymara Fassarela; Costa, Isolda; Pinto, Nadja Cristhina de Souza; de Medeiros, Silvia Regina Batistuzzo

2014-04-01

186

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

SciTech Connect

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%.

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

2011-02-15

187

Surface roughening of silicon, thermal silicon dioxide, and low-k dielectric coral films in argon plasma  

SciTech Connect

The surface roughness evolutions of single crystal silicon, thermal silicon dioxide (SiO{sub 2}), and low dielectric constant film coral in argon plasma have been measured by atomic force microscopy as a function of ion bombardment energy, ion impingement angle, and etching time in an inductively coupled plasma beam chamber, in which the plasma chemistry, ion energy, ion flux, and ion incident angle can be adjusted independently. The sputtering yield (or etching rate) scales linearly with the square root of ion energy at normal impingement angle; additionally, the angular dependence of the etching yield of all films in argon plasma followed the typical sputtering yield curve, with a maximum around 60 deg. -70 deg. off-normal angle. All films stayed smooth after etching at normal angle but typically became rougher at grazing angles. In particular, at grazing angles the rms roughness level of all films increased if more material was removed; additionally, the striation structure formed at grazing angles can be either parallel or transverse to the beam impingement direction, which depends on the off-normal angle. More interestingly, the sputtering caused roughness evolution at different off-normal angles can be qualitatively explained by the corresponding angular dependent etching yield curve. In addition, the roughening at grazing angles is a strong function of the type of surface; specifically, coral suffers greater roughening compared to thermal silicon dioxide.

Yin Yunpeng; Sawin, Herbert H. [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2008-01-15

188

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)

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.

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

2012-01-01

189

Measurement of hydroxyl radical (OH) concentration in an argon RF plasma jet by laser-induced fluorescence  

NASA Astrophysics Data System (ADS)

The concentration of hydroxyl (OH) radicals in a plasma pencil, an atmospheric RF plasma jet ignited in argon, was measured by laser-induced fluorescence calibrated by Rayleigh scattering on ambient air. A suitable excitation scheme for this discharge was suggested based on laser excitation to the lowest vibrational level of the A 2?+ state. Effects of spectral overlap between the laser and absorption line, fluorescence saturation, temporal evolution of fluorescence radiation, rotational energy transfer and rotational distribution on the diagnostic method were analysed. The maximum OH concentration was approximately 5 × 1020 m-3. The maximum was reached when the measurement point localized in the effluent of the plasma pencil was inside but close to the tip of the visible active discharge.

Vorá?, J.; Dvo?ák, P.; Procházka, V.; Ehlbeck, J.; Reuter, S.

2013-04-01

190

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

NASA Astrophysics Data System (ADS)

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.

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

2011-10-01

191

Contribution of a portable air plasma torch to rapid blood coagulation as a method of preventing bleeding  

NASA Astrophysics Data System (ADS)

The effectiveness and mechanism of a low temperature air plasma torch in clotting blood are explored. Both blood droplets and smeared blood samples were used in the tests. The treated droplet samples reveal how blood clotting depends on the distance at which the torch operated, and for how long the droplets have been exposed to the torch. Microscopy and cell count of smeared blood samples shed light on dependencies of erythrocyte and platelet counts on torch distance and exposure time. With an increase of torch distance, the platelet count of treated blood samples increases but is less than that of the control. The flux of reactive atomic oxygen (RAO) and the degree of blood clotting decreased. With an increase of exposure time, platelet count of treated samples decreased, while the degree of clot increased. The correlation among these dependencies and published data support a blood clotting mechanism that RAO as well as other likely reactive oxygen species generated by the plasma torch activate erythrocyte-platelets interactions and induces blood coagulation.

Kuo, S. P.; Tarasenko, O.; Chang, J.; Popovic, S.; Chen, C. Y.; Fan, H. W.; Scott, A.; Lahiani, M.; Alusta, P.; Drake, J. D.; Nikolic, M.

2009-11-01

192

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

SciTech Connect

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.

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

193

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

NASA Astrophysics Data System (ADS)

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.

Tholeti, Siva Sashank; Shneider, Mikhail N.; Alexeenko, Alina A.

2014-06-01

194

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

NASA Astrophysics Data System (ADS)

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.

Wiebold, Matthew D.

195

Soft X-ray optimization studies on a dense plasma focus device operated in neon and argon in repetitive mode  

Microsoft Academic Search

This paper investigates the emission characteristics of a\\u000a high-performance low-energy (3-kJ) repetitive dense plasma focus device,\\u000a NX2, operated at up to 1-Hz repetition rate to develop it as an intense\\u000a source of soft X-rays (SXR) for microlithography and micromachining.\\u000a Various SXR yield optimization studies with argon and neon as filling\\u000a gases were performed under different operating conditions (charging\\u000a voltage, filling

D. Wong; A. Patran; T. L. Tan; R. S. Rawat; P. Lee

2004-01-01

196

Self-absorbing method to measure the population of the metastable levels in an argon microwave plasma at atmospheric pressure  

NASA Astrophysics Data System (ADS)

Metastable atoms play an important role in the kinetics of plasmas. A self-absorbing method has been used to determine the population density of Ar(3P0) and Ar(3P2) atomic metastable levels and Ar(1P1) and Ar(3P1) atomic resonant levels in an argon microwave discharge sustained by a surface wave at atmospheric pressure. Under the operative conditions investigated, the concentrations of these levels ranged from 1010 1012 cm-3, being in agreement with those reported in the literature, which seems to indicate that this method could be used for this calculation.

Santiago, I.; Christova, M.; García, M. C.; Calzada, M. D.

2004-12-01

197

Low-temperature atmospheric pressure argon plasma treatment and hybrid laser-plasma ablation of barite crown and heavy flint glass.  

PubMed

We report on atmospheric pressure argon plasma-based surface treatment and hybrid laser-plasma ablation of barite crown glass N-BaK4 and heavy flint glass SF5. By pure plasma treatment, a significant surface smoothing, as well as an increase in both the surface energy and the strength of the investigated glass surfaces, was achieved. It was shown that for both glasses, hybrid laser plasma ablation allows an increase in the ablation depth by a factor of 2.1 with respect to pure laser ablation. The ablated volume was increased by an averaged factor of 1.5 for N-BaK4 and 3.7 for SF5. PMID:22695664

Gerhard, Christoph; Roux, Sophie; Brückner, Stephan; Wieneke, Stephan; Viöl, Wolfgang

2012-06-10

198

The interplay between platelets and coagulation  

Microsoft Academic Search

Platelet activation and blood coagulation are two processes often studied separately, but which cannot be seen independently from each other. Platelets play a pivotal role in coagulation, not only by providing negatively charged phospholipids, but also in localizing the coagulation process from a diffuse plasma environment to an anionic surface, most likely via specific receptors on the platelets. On the

C. Weeterings

2009-01-01

199

New BRP for human plasma calibrated for coagulation factors V, VIII, XI and XIII - collaborative study for establishment of batches 1 and 2.  

PubMed

A human plasma reference preparation in International Units (IU) must be used in each potency assay of the human coagulation factors V, VIII and XI in human plasma pooled and treated for virus inactivation, according to the European Pharmacopoeia (Ph. Eur.) monograph 1646 and general chapters 2.7.4 and 2.7.22 respectively, and in the potency assay of human coagulation factor XIII in fibrin sealant kits, according to Ph. Eur. monograph 0903. International reference standards for all of these factors are now established, however, regional reference standards were not available for the required routine use. It was therefore proposed by European OMCLs and manufacturers to establish a European reference preparation, and it was the goal of this study to accomplish that. Two candidate biological reference preparations (BRPs), separate lyophilisation lots of the same normal human plasma bulk material, were calibrated against the International Standards (ISs) for human coagulation factors V, VIII, XI and XIII. Twelve European laboratories including OMCLs and manufacturers participated. The candidate material was tested against the ISs in 4 separate assays for each factor using the methods described in the relevant Ph. Eur. monographs and general chapters. No discernable difference was noted between the activities of the 2 candidates. They were shown to be suitable for their intended use and it was recommended to assign to both batches a potency of 0.73 IU/mL for factor V, 0.74 IU/mL for factor VIII, 0.59 IU/mL for factor XI and 0.79 IU/mL for factor XIII. Candidate batch B is proposed to be used first as lot 1, followed upon its depletion by candidate batch A (lot 2). The BRP batches will be monitored regularly for potency throughout their lifetime. EDQM BRP batches 1 and 2 of coagulation factors V, VIII, XI and XIII plasma were formally adopted by the Ph. Eur. Commission at their session in June 2011. PMID:22225765

Bayer, P; Daas, A; Milne, C

2011-11-01

200

Determination of Triton X-100 in plasma-derived coagulation factor VIII and factor IX products by reversed-phase high-performance liquid chromatography  

Microsoft Academic Search

Plasma protein pools are often virus-inactivated by the solvent–detergent method, using tri-n-butyl phosphate and Triton X-100, followed by removal and determination of these compounds. We used reversed-phase high-performance liquid chromatography for the determination of Triton X-100 in coagulation factor VIII and factor IX products, Octonativ-M and Nanotiv, respectively (Pharmacia, Stockholm, Sweden). The chromatographic system included a C18 silica column and

Göran Karlsson; Ann-Charlotte Hinz; Elisabeth Henriksson; Stefan Winge

2002-01-01

201

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

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

Cohen, David

202

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)

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.

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

2014-11-01

203

Interferometric investigation of the influence of argon buffer gas on the characteristics of laser-induced aluminum plasmas.  

PubMed

An interferometric analysis was performed to investigate the influence of argon (Ar) buffer gas on the characteristics of laser-induced aluminum (Al) plasma at atmospheric pressure. The plasma was produced by focusing a Q-switched Nd:YAG laser pulse (?=1064??nm, pulse duration ?5??ns, E=6.0??mJ) onto an Al target. The interference patterns were constructed using a Nomarski interferometer incorporated with a frequency-doubled, Q-switched Nd:YAG laser (?=532??nm, pulse duration ?10??ns) that generates an interferometric probe beam. The interferometric measurements were carried out as a function of the elapsed time after the onset of breakdown under the conditions of open air and an Ar gas jet flow (5??l/min). With the injection of an Ar buffer gas jet in the ablation process, an increase in electron density and a preferential axial plasma expansion of the plasma plume were observed during the early stages of plasma formation as a consequence of increased inverse-Bremsstrahlung (IB) absorption efficiency. PMID:24921120

Oh, Seong Y; Singh, Jagdish P; Lim, Changhwan

2014-06-10

204

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

PubMed

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

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

2014-12-01

205

Determination of the Gas Temperature of an Argon Microwave Plasma at Atmospheric Pressure Using van der Waals Broadening  

NASA Astrophysics Data System (ADS)

For the gas temperature determination for a discharge at atmospheric pressure, the ro-vibrational emission spectra of the molecular species are usually used, but exist cases when it is difficult to detect them. In order to analyze the possibility to use the van der Waals broadening of the neutral-argon lines to determine the gas temperature in an argon surface-wave sustained discharge (SWD) at atmospheric pressure, the values of the gas temperature inferred from the atomic lines with that ones obtained from the analysis of the OH molecular specie spectrum, were compared. If the Lorentzian broadening of a spectral line depends on axial position, this line is sensitive to the electron density variation. This is in particular the case for the 522.1, 549.6 and 603.2 nm lines. For this reason, these lines could be used to measure the electron density in discharges at atmospheric pressure. For these spectral lines a linear fit is obtained, which intersects the ordinate at a point corresponding to the Lorentzian width for zero electron density. This value can be considered approximately equal to the van der Waals width and is used here to calculate the plasma gas temperature. From our results and the comparison with other authors we can conclude that the method, proposed in this work, gives a possibility to estimate the gas temperature from the van der Waals broadening of atomic lines.

Yubero, Cristina; Dimitrijevi?, Milan S.; Garcia, Maria Carmen; Calzada, Maria Dolores

2007-09-01

206

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

NASA Astrophysics Data System (ADS)

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 plasma images captured in a time-resolution range of as fine as 10 µs shows that the converging point is actually a time-averaged visual effect and the converging point does not exist when the plasma is visualized under high time resolution, e.g. <2 ms. Simulations of the emission spectra of OH, N2 and N_{2}^{+} in the range 200-450 nm enable the plasma electronic excitation temperature (Texc) to be determined at 8000-9000 K, while the vibrational temperature (Tv), the rotational temperature (Tr) and the gas temperature (Tg) at different locations along the axis of the plasma column are all determined to be in the range 1800-2200 K. Thermal equilibrium properties of the plasma are discussed. OH radical concentrations along the plasma column axis are measured by CRDS and the concentrations are in the range 1.6 × 1013-3.0 × 1014 cm-3 with the highest density at the tail of the plasma column. The upper limit of electron density ne is estimated to be 5.0 × 1014 cm-3 from the Lorentzian component of the broadened lineshape obtained by ringdown spectral scans of the rovibrational line S21 of the OH A-X (0-0) band.

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

2009-05-01

207

Gas temperature effect on the time for onset of particle nucleation in argon diluted acetylene plasma  

E-print Network

, Serbia and Montenegro 1. Introduction Particle nucleation in processing plasmas is an important issue to understand the basic problems of the involved plasma chemistry. On the other hand it is interesting plasma I. Stefanovi1, 2 , E. Kovacevi1 , J. Berndt1 , and J. Winter1 1 Institute for Experimental Physics

Paris-Sud XI, Université de

208

Coagulopathies in Naja naja karachiensis (black Pakistan cobra) bites and its effect on coagulation tests upon storage of platelet-poor plasma.  

PubMed

The aim of this study was to evaluate the effect of venom from Naja naja karachiensis on platelet-poor plasma, activated partial thromboplastin time (aPTT), prothrombin time (PT) / international normalized ratio (INR), thrombin time (TT) and to evaluate its effect on clotting time upon storage of plasma for a specific time period with possible mechanism responsible for that. Prolongation of PT / INR, aPTT and TT was observed when different concentrations of venom were introduced due to degeneration of fibrinogen. Preservation of plasma for three months further prolong clotting time for coagulation tests, however, difference of PT and TT results were not very prominent as compared to aPTT. Minute concentrations of cobra venom and short as well as long storage of platelet-poor plasma badly affects the INR ratio. PMID:23285662

Asad, Muhammad Hassham Hassan Bin; Razi, Muhammad Tahir; Khan, Taous; Najam-Us-saqib, Qazi; Murtaza, Ghulam; Hussain, Muhammad Shahzad; Hussain, Muhammad Sikandar; Karim, Sabiha; Hussain, Izhar

2012-01-01

209

Double layer-like structures in the core of an argon helicon plasma source with uniform magnetic fields  

SciTech Connect

A hot (T{sub e} ? 10?eV) electron population is observed in the core of a 3 mTorr argon helicon plasma source at 500?W RF power and 900 G uniform axial magnetic field strength, 12?cm from the edge of the helicon antenna. A double layer-like structure consisting of a localized axial electric field of approximately 8?V/cm over 1–2?cm is observed adjacent to the hot electron population. The potential step generated by the electric field is shown to be large enough to trap the hot electrons. To our knowledge this is the first observation of these structures in the core of a helicon discharge.

Umair Siddiqui, M., E-mail: musiddiqui@wisc.edu; Hershkowitz, Noah [Department of Engineering Physics, University of Wisconsin—Madison, Madison, Wisconsin 53706 (United States)] [Department of Engineering Physics, University of Wisconsin—Madison, Madison, Wisconsin 53706 (United States)

2014-02-15

210

Effects of matching network on the hysteresis during E and H mode transitions in argon inductively coupled plasma  

SciTech Connect

An experimental investigation of the hysteresis during the E (capacitive coupling) and H mode (inductive coupling) transitions at various matching situation in argon inductively coupled plasma is reported. At high pressure, the results show two hysteresis loops involved the plasma density, applied power, and forward power, as well as the electrical parameters in the discharge circuit, when the series capacitance is cycled. The measured electron density versus applied power shows that the hysteresis loop shrinks with the decrease of the matching capacitance, and the same trend is discovered on the input current, voltage, and phase angle. In addition, for the case of small capacitance, the current (or voltage) jumps to a low value when the discharge passes through the E to H mode transition regime. Contrarily, for the case of large capacitance, the current jumps to a high value while the voltage is almost constant. The evolution characteristics of the plasma and circuit parameters observed imply that the nonlinear behavior of the matching situation may be one of the determined factors for hysteresis.

Gao Fei; Zhao Shuxia; Li Xiaosong; Wang Younian [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

2010-10-15

211

Temporal variations in the excitation temperature of a laser-induced argon plasma estimated with copper emission lines.  

PubMed

A time-resolved spectrometric measurement was conducted to determine temporal variations in the excitation temperature within a single laser plume caused by a Nd:YAG laser plasma. The two-line method using copper atomic lines was employed to estimate the excitation temperature. Two line pairs of copper lines: Cu I 521.82/Cu I 510.55 and Cu I 515.32/Cu I 510.55, were measured by using an Echelle spectrograph equipped with an ICCD detector having a high-speed gating. The excitation temperature was gradually elevated with the progress of the plasma expansion. This result cannot be explained from a direct excitation model in which excited species are principally produced through collisions with energetic particles, but from an indirect excitation model in which second-kind collisions with argon metastables and subsequent step-wise de-excitations produce the excited species. In the latter case, high-lying states of copper atoms are more populated compared to the population expected from the Boltzmann distribution. Temporal variations in the emission intensities of copper atomic lines requiring large excitation energies were also measured, and their emissions remained even in the expansion stage of the laser-induced plasma. This result also implies the over-population of high-lying copper excited levels. PMID:19359786

Sasaki, Yo; Wagatsuma, Kazuaki

2009-04-01

212

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

NASA Astrophysics Data System (ADS)

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.

van Gessel, Bram; Brandenburg, Ronny; Bruggeman, Peter

2013-08-01

213

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

214

Effects of the shielding cylinder and substrate on the characteristics of an argon radio-frequency atmospheric glow discharge plasma jet  

SciTech Connect

With unique features of low breakdown voltages, large and uniform discharge areas and high concentrations of chemically reactive species, radio-frequency, atmospheric-pressure glow discharge (rf APGD) plasma sources produced with bare-metallic electrodes have shown promising prospects in the field of materials processing. In this paper, the spatial distributions (i.e., the directly measured integrated axial distribution and the radial distribution by using the inverse Abel transform) of the emission intensities of the Ar I 696.5 nm line are studied for the argon rf APGD plasma jet under different operation conditions, including variations of the rf power input or the argon flow rate, the existence of the solid shielding cylinder or the substrate. The experimental results show that, with other parameters being unchanged, the emission intensities of the Ar I 696.5 nm line increase with increasing the rf power input or the argon flow rate; and the solid shielding cylinder has more significant influences on the characteristics of the plasma impinging jet by reducing the mass flow rate of the ambient air entrained into the plasma jet region than those for the cases without the existence of the substrate at the downstream of the plasma torch nozzle exit.

Li Guo; Le Peisi; Li Heping; Bao Chengyu [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

2010-05-15

215

In situ absolute air, O3 and NO densities in the effluent of a cold RF argon atmospheric pressure plasma jet obtained by molecular beam mass spectrometry  

NASA Astrophysics Data System (ADS)

A molecular beam mass spectrometer has been calibrated and used to measure the air entrainment, nitric oxide and ozone concentrations in the effluent of a cold atmospheric pressure argon RF driven plasma jet. The approaches for calibrating the mass spectrometer for different species are described in detail. Gas phase densities of ozone and nitric oxide up to 7.5 ppm and 4 ppm, respectively, have been measured in the far effluent of the argon plasma jet. The difference in air entrainment when the plasma is undisturbed or is close to a well, which is the case for e.g. in vitro plasma-cell interaction studies, is shown. In addition, an exponential decay of the positive ion flux as a function of distance in the effluent is obtained. Furthermore, the effect of plasma power, duty cycle and air and O2 admixtures introduced into the argon flow on the NO and O3 production is presented, including the possibility of independent control of the NO and O3 flux from the jet.

van Ham, B. T. J.; Hofmann, S.; Brandenburg, R.; Bruggeman, P. J.

2014-06-01

216

Plasma parameters and electromagnetic forces induced by the magneto hydro dynamic interaction in a hypersonic argon flow experiment  

SciTech Connect

This work proposes an experimental analysis on the magneto hydro dynamic (MHD) interaction induced by a magnetic test body immersed into a hypersonic argon flow. The characteristic plasma parameters are measured. They are related to the voltages arising in the Hall direction and to the variation of the fluid dynamic properties induced by the interaction. The tests have been performed in a hypersonic wind tunnel at Mach 6 and Mach 15. The plasma parameters are measured in the stagnation region in front of the nozzle of the wind tunnel and in the free stream region at the nozzle exit. The test body has a conical shape with the cone axis in the gas flow direction and the cone vertex against the flow. It is placed at the nozzle exit and is equipped with three permanent magnets. In the configuration adopted, the Faraday current flows in a closed loop completely immersed into the plasma of the shock layer. The electric field and the pressure variation due to MHD interaction have been measured on the test body walls. Microwave adsorption measurements have been used for the determination of the electron number density and the electron collision frequency. Continuum recombination radiation and line radiation emissions have been detected. The electron temperature has been determined by means of the spectroscopic data by using different methods. The electron number density has been also determined by means of the Stark broadening of H{sub {alpha}} and the H{sub {beta}} lines. Optical imaging has been utilized to visualize the pattern of the electric current distribution in the shock layer around the test body. The experiments show a considerable effect of the electromagnetic forces produced by the MHD interaction acting on the plasma flow around the test body. A comparison of the experimental data with simulation results shows a good agreement.

Cristofolini, Andrea; Neretti, Gabriele; Borghi, Carlo A. [Department of Electrical Engineering, University of Bologna, Viale Risorgimento 2, 40136 Bologna (Italy)

2012-08-01

217

[Application of argon-nitrogen mixed gas inductively coupled plasma in elements and isotopes analysis].  

PubMed

To improve the precision and accuracy of elements and isotopes analysis in traditional Ar-ICP, the addition of nitrogen in ICP has been widely used. The present review focused on the discussions of the basic physical and chemical properties of the Ar-N2 mixed gas inductively coupled plasma and the mechanisms of the special nature of Ar-N2 mixed gas plasma. The applications of Ar-N2 inductively coupled plasma in spectral analysis and mass spectrometry analysis in the past 40 years were summarized. The authors also give an overall outlook on the application of this technology. PMID:24059205

Liu, Sheng-Hua; Chen, Tao; Li, Zhen; Wang, Li-Yun; Liu, Yong-Sheng; Hu, Sheng-Hong; Hu, Zhao-Chu

2013-07-01

218

Synthesis of ultrafine ceramic and metallic powders in a thermal argon rf plasma  

SciTech Connect

Ultrafine powders of SiC, Si/sub 3/N/sub 4/, Ni, and Al/sub 2/O/sub 3/ have been prepared in a rf-plasma reactor, utilizing an induction plasma tube designed at Los Alamos. The primary particle size of the ceramic powders ranges from 5 to 50 nm. Silicon carbide and alumina are ultrapure crystalline powders, while silicon nitride is amorphous for surface areas greater than 100 m/sup 2//g. Plasma nickel powder will sinter to full density at 1073 K.

Vogt, G.J.; Vigil, R.S.; Newkirk, L.R.; Trkula, M.

1985-01-01

219

Effect of argon and hydrogen on deposition of silicon from tetrochlrosilane in cold plasmas  

NASA Technical Reports Server (NTRS)

The roles of Ar and H2 on the decomposition of SiCl4 in cold plasma were investigated by Langmuir probes and mass spectrometry. Decomposition of the reactant by Ar only has been found to be very slow. In presence of H2 in the plasma SiCl4 is decomposed by fast radical-molecule reactions which are further enhanced by Ar due to additional ion-molecule reactions in which more H radicals are produced. A model for the plasma-surface interactions during deposition of mu-Si in the Ar + H2 + SiCl4 system is presented.

Manory, R. R.; d.

1985-01-01

220

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

221

Numerical simulation study on fluid dynamics of plasma window using argon  

SciTech Connect

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.

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

222

Numerical simulation study on fluid dynamics of plasma window using argon  

NASA Astrophysics Data System (ADS)

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.

Huang, S.; Zhu, K.; Shi, B. L.; Lu, Y. R.; Hershcovitch, A.; Yang, L.; Zhang, X. Y.; Wei, G. D.

2013-07-01

223

Production of high quality syngas from argon/water plasma gasification of biomass and waste.  

PubMed

Extremely hot thermal plasma was used for the gasification of biomass (spruce sawdust, wood pellets) and waste (waste plastics, pyrolysis oil). The plasma was produced by a plasma torch with DC electric arc using unique hybrid stabilization. The torch input power of 100-110 kW and the mass flow rate of the gasified materials of tens kg/h was set up during experiments. Produced synthetic gas featured very high content of hydrogen and carbon monoxide (together approximately 90%) that is in a good agreement with theory. High quality of the produced gas is given by extreme parameters of used plasma--composition, very high temperature and low mass flow rate. PMID:24148259

Hlina, M; Hrabovsky, M; Kavka, T; Konrad, M

2014-01-01

224

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

PubMed

Exposure of tissue factor (TF)-bearing cells to blood is the initial event in coagulation and intravascular thrombus formation. However, the mechanisms which determine 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 pathway-inhibited, non-flowing human plasma. Human aortic endothelial cells, smooth muscle cells, macrophages and lung fibroblasts differed in their ability to support thrombin generation in microplate assay with peaks of generated thrombin of 60 +/- 53 nmol L(-1), 135 +/- 57 nmol L(-1), 218 +/- 55 nmol L(-1) and 407 +/- 59 nmol L(-1) (mean +/- SD), respectively. Real-time videomicroscopy revealed the initiation and spatial growth phases of clot formation. Different procoagulant activity of cell monolayers was manifested as up to 4-fold difference in the lag times of clot formation. In contrast, the clot growth rate, which characterized propagation of clotting from the cell surface to plasma, was largely independent of cell type (< or = 30% difference). Experiments with factor VII (FVII)-, FVIII-, FX- or FXI-deficient plasmas and annexin V revealed that (i) cell surface-associated extrinsic Xase was critical for initiation of clotting; (ii) intrinsic Xase regulated only the growth phase; and (iii) the contribution of plasma phospholipid surfaces in the growth phase was predominant. We conclude that the role of TF-bearing initiator cells is limited to the initial stage of clot formation. The functioning of intrinsic Xase in plasma provides the primary mechanism of sustained and far-ranging propagation of coagulation leading to the physical expansion of a fibrin clot. PMID:15670039

Ovanesov, M V; Ananyeva, N M; Panteleev, M A; Ataullakhanov, F I; Saenko, E L

2005-02-01

225

Changes in Plasma Levels of Natural Anticoagulants in Disseminated Intravascular Coagulation: High Prognostic Value of Antithrombin and Protein C in Patients with Underlying Sepsis or Severe Infection  

PubMed Central

Background Dysfunctional natural anticoagulant systems enhance intravascular fibrin for mation in disseminated intravascular coagulation (DIC), and plasma levels of natural anti coagulants can be used in the diagnosis and prognosis of DIC. Herein, the diagnostic value of 4 natural anticoagulants was assessed, and the prognostic value of antithrombin and protein C were validated in a large population. Methods Part 1 study included 126 patients with clinically suspected DIC and estimated plasma levels of 4 candidate anticoagulant proteins: antithrombin, protein C, protein S, and protein Z. Part 2 comprised 1,846 patients, in whom plasma antithrombin and protein C levels were compared with other well-known DIC markers according to the underlying dis eases. The 28-day mortality rate was used to assess prognostic outcome. Results Antithrombin and protein C showed higher areas under the ROC curve than pro tein S and protein Z. In part 2 of the study, antithrombin and protein C levels significantly correlated with DIC score, suggesting that these factors are good indicators of DIC severity. Antithrombin and protein C showed significant prognostic power in Kaplan-Meier analyses. In patients with sepsis/severe infection, antithrombin and protein C showed higher hazard ratios than D-dimer. Platelet count showed the highest hazard ratio in patients with hemato logic malignancy. In patients with liver disease, the hazard ratio for antithrombin levels was significantly high. Conclusions Decreased plasma anticoagulant levels reflect florid consumption of the phys iologic defense system against DIC-induced hypercoagulation. Plasma antithrombin and protein C levels are powerful prognostic markers of DIC, especially in patients with sepsis/severe infection. PMID:24624342

Choi, Qute; Hong, Ki Ho; Kim, Ji-Eun

2014-01-01

226

A differentially pumped argon plasma in the linear plasma generator Magnum-PSI: gas flow and dynamics of the ionized fraction  

NASA Astrophysics Data System (ADS)

Magnum-PSI is a linear plasma generator designed to reach the plasma-surface interaction (PSI) regime of ITER and nuclear fusion reactors beyond ITER. To reach this regime, the influx of cold neutrals from the source must be significantly lower than the plasma flux reaching the target. This is achieved by a differential pumping scheme, where the vacuum vessel is divided by skimmers into separate chambers which are individually pumped. The non-magnetized expansion of 5 Pa m3 s-1 (3 slm) argon in a low background pressure was studied in the differentially pumped vacuum vessel fitted with non-cooled flat skimmers. The behavior of the neutral component was studied with direct simulation Monte Carlo simulations and Rayleigh scattering measurements. Thomson scattering and double Langmuir probe measurements were performed on the ionized fraction. It was found that the electrons and neutral particles are not completely coupled in the shock front. The neutral fraction shows clear signs of invasion from hotter background gas, causing the average temperature and density to increase before the shock. This is also shown in the ionization ratio, which has been determined in front of and behind the first skimmer. This study helps us to understand the behavior of the gas flow in the machine and validates our modeling.

van Eck, H. J. N.; Hansen, T. A. R.; Kleyn, A. W.; van der Meiden, H. J.; Schram, D. C.; Zeijlmans van Emmichoven, P. A.

2011-08-01

227

Deposition of amorphous hydrogenated silicon carbide films using organosilanes in an argon\\/hydrogen plasma  

Microsoft Academic Search

Nearly stoichiometric, amorphous silicon carbide films with a relatively low hydrogen content were deposited from organsilanes on a variety of substrates in a microwave-generated plasma without external heating. The films undergo little weight loss upon pyrolysis to 800 [degree]C. The effect of the different deposition parameters on the film composition and the exhaust gas was established through a battery of

Leon Maya

1994-01-01

228

Endothermic reactions between mullite and silicon carbide in an argon plasma environment  

SciTech Connect

Reactions between SiC and mullite in an Ar plasma were investigated using a model composite in which a free-standing CVD SiC coupon was imbedded in mullite cement. After treatment in a radio frequency (RF) plasma, the Si content of the mullite in contact with SiC was found to be less than that in the starting material, and deposits were found on the walls of the plasma chamber due to the reaction of mullite with SiC as follows: Al{sub 6}Si{sub 2}O{sub 13}(s) + SiC(s) = 3Al{sub 2}O{sub 3}(s) + 3SiO(g) + CO(g). This reaction, which is endothermic (1,405 kJ/mol at 1,500 K), absorbs thermal energy and consequently prevents the rapid sintering which is observed for single-phase mullite in similar environments. As a consequence, it is suggested that RF plasma sintering probably cannot be used to densify SiC-reinforced mullite-matrix composites because of the resulting energy consumption and damage to the SiC phase.

Park, Y. [Univ. of Illinois, Chicago, IL (United States). Dept. of Materials Science Engineering]|[Los Alamos National Lab., NM (United States). Materials Science and Technology Div.; McNallan, M.J. [Univ. of Illinois, Chicago, IL (United States). Dept. of Materials Science Engineering; Butt, D.P. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

1998-01-01

229

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

SciTech Connect

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 {sup 3}P{sub 2}, {sup 3}P{sub 0} (metastable atoms) and {sup 3}P{sub 1} (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.

Munoz, J.; Margot, J. [Departement de Physique, Universite de Montreal, C.P. 6128, Succ. Centre-ville, Montreal, Quebec H3C 3J7 (Canada); Calzada, M. D. [Grupo de Espectroscopia de Plasmas, Edificio A. Einstein, Campus de Rabanales, Universidad de Cordoba, E-14071 Cordoba (Spain)

2012-01-15

230

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

SciTech Connect

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.

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

231

Atomic oxygen in a cold argon plasma jet: TALIF spectroscopy in ambient air with modelling and measurements of ambient species diffusion  

Microsoft Academic Search

By investigating the atomic oxygen density in its effluent, two-photon absorption laser-induced fluorescence (TALIF) spectroscopy measurements are for the first time performed in a cold argon\\/oxygen atmospheric pressure plasma jet. The measurements are carried out in ambient air and quenching by inflowing air species is considered. We propose a novel absorption technique in the VUV spectral range, where emission originating

S Reuter; J Winter; A Schmidt-Bleker; D Schroeder; H Lange; N Knake; V Schulz-von der Gathen; K-D Weltmann

2012-01-01

232

Modeling and characterization of hydrogen and hydrogen-argon discharges in resonant cavity microwave plasma reactors  

Microsoft Academic Search

Summary form only given. Resonant-cavity microwave plasma reactors used to generate hydrogen and hydrogen-containing mixed gas discharges are modeled and characterized over a pressure range from 0.1 mTorr to 100 Torr. The model developed describes the electromagnetic fields in the cylindrical resonating microwave cavity which excites and maintains the discharge. The numerical technique used is 3-D finite-difference time-domain solution of

T. A. Grotjohn; G. L. King; W. Tan; V. Gopinath

1993-01-01

233

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

234

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

SciTech Connect

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.

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

1988-06-01

235

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

SciTech Connect

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.

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

2014-10-07

236

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

SciTech Connect

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.

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

237

Coagulation in sepsis  

Microsoft Academic Search

Coagulation abnormalities, ranging from a simple fall in platelet count to full-blown disseminated intravascular coagulation, are a common occurrence in critically ill patients and have been associated with increased mortality. In sepsis, activation of the extrinsic coagulation pathway by tissue factor induces increased coagulation, and simultaneous depression of the inhibitory mechanisms of coagulation, and suppression of the fibrinolytic system results

André Amaral; Steven M. Opal; Jean-Louis Vincent

2004-01-01

238

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

PubMed Central

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

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

2012-01-01

239

Temporal Evolution of Excited Level Populations in a High-Velocity Argon Plasma Flow  

NASA Astrophysics Data System (ADS)

A simplified collisional-radiative model is applied to a high velocity plasma flow through the arcjet nozzle to investigate the temporal evolution of excited level population densities in the selected spatial positions inside arcjet thruster. Computations are carried out for various sets of input parameters such as electron temperature, electron number density, atom temperature, and pressure. The numerical results illustrate that the extent of the ionization-recombination non-equilibrium is strongly dependent on the electron temperature and pressure, and is significantly affected by resonance radiation.

Sun, Su-Rong; Wang, Hai-Xing

2014-09-01

240

Argon/UF6 plasma experiments: UF6 regeneration and product analysis  

NASA Technical Reports Server (NTRS)

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.

Roman, W. C.

1980-01-01

241

Deposition of amorphous hydrogenated silicon carbide films using organosilanes in an argon/hydrogen plasma  

SciTech Connect

Nearly stoichiometric, amorphous silicon carbide films with a relatively low hydrogen content were deposited from organsilanes on a variety of substrates in a microwave-generated plasma without external heating. The films undergo little weight loss upon pyrolysis to 800 [degree]C. The effect of the different deposition parameters on the film composition and the exhaust gas was established through a battery of tests including infrared Fourier transform spectroscopy, Auger electron spectroscopy, x-ray photoelectron spectroscopy, ellipsometry, and mass spectroscopy. For a given power level there is a limiting feeding rate of the precursor under which operation of the system is dominated by thermodynamics and thus leads to the desired product. Beyond that limit, excessive hydrogen incorporation and carbosilane polymer formation takes place. The hydrogen content of the plasma is also an important parameter affecting the chemistry of the deposition. In the thermodynamically dominated regime the nature of the precursor has no effect on the quality of the film. It affects only the relative utilization efficiency.

Maya, L. (Chemistry Division, Oak Ridge National Laboratory, P.O. Box 2008-6119, Oak Ridge, Tennessee 37831 (United States))

1994-05-01

242

Systems Biology of Coagulation  

PubMed Central

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

Diamond, Scott L.

2013-01-01

243

Improvement of In-Flight Alumina Spheroidization Process Using a Small Power Argon DC-RF Hybrid Plasma Flow System by Helium Mixture  

NASA Astrophysics Data System (ADS)

For the further improvement of in-flight alumina spheroidization process with a low-power direct-current radiofrequency (DC-RF) hybrid plasma flow system, the effect of a small amount of helium gas mixture in argon main gas and also the effect of increasing DC nozzle diameter on powder spheroidization ratio have been experimentally clarified with correlating helium gas mixture percentage, plasma enthalpy, powder in-flight velocity, and temperature. The alumina spheroidization ratio increases by helium gas mixture as a result of enhancement of plasma enthalpy. The highest spheroidization ratio is obtained by 4% mixture of helium in central gas with enlarging nozzle diameter from 3 to 4 mm, even under the constant low input electric power given to a DC-RF hybrid plasma flow system.

Takana, Hidemasa; Jang, Juyong; Igawa, Junji; Nakajima, Tomoki; Solonenko, Oleg P.; Nishiyama, Hideya

2011-03-01

244

Dynamics of the spectral behaviour of an ultrashort laser pulse in an argon-gas-filled capillary discharge-preformed plasma channel  

NASA Astrophysics Data System (ADS)

We have reported the argon plasma waveguide produced in an alumina (Al2O3) capillary discharge and used to guide ultrashort laser pulses at intensities of the order of 1016 W/cm2. A one-dimensional magnetohydrodynamic (MHD) code was used to evaluate the average degree of ionization of Ar in the preformed plasma channel. The spectrum of the propagated laser pulse in the Ar plasma waveguide was not modified and was well reproduced by a particle-in-cell (PIC) simulation under initial ion charge state of Ar3+ 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.

Sakai, S.; Higashiguchi, T.; Yugami, N.; Bobrova, N.; Sentoku, Y.; Kodama, R.

2013-11-01

245

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

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

246

Investigation into the behavior of metal-argon polyatomic ions (MAr+) in the extraction region of inductively coupled plasma-mass spectrometry  

NASA Astrophysics Data System (ADS)

The abundances of metal-argon polyatomic ions (MAr+) are determined in inductively coupled plasma-mass spectrometry (ICP-MS). The ratios of MAr+ abundance to that for M+ ions are measured experimentally. These ratios are compared to expected values, calculated for typical plasma conditions using spectroscopic data. For all metals studied (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn), the measured ratios are significantly lower than the calculated ratios. Increasing the plasma potential (and thereby increasing the ion kinetic energy) by means of a homemade guard electrode with a wide gap further reduces the MAr+/M+ ratio. Implementing a skimmer cone designed for high transmission of light ions increases the MAr+ abundance. Considering this evidence, the scarcity of MAr+ ions is attributed to collision induced dissociation (CID), likely due to a shock wave at the tip of or in the throat of the skimmer cone.

Ebert, Chris H.; Witte, Travis M.; Houk, R. S.

2012-10-01

247

Examination of Ion Beam Acceleration in A High Power-Low Pressure and Gas Flow Rates Argon Plasma Created in the MadHeX Helicon Source  

NASA Astrophysics Data System (ADS)

The modified MadHeX experimental system consists of a Pyrex tube connected to a stainless steel chamber with an axial magnetic nozzle field, variable up to 1 kG at the source region that has been upgraded to minimize neutral reflux and reduce neutral concentrations in the chamber. A half-turn double-helix antenna is used to excite helicon waves in the source. An ion beam of energy, E = 160 eV at 500 W RF power, has been observed in a low flowing argon plasma formed in the expanding region with a 340 G magnetic field. The role of plasma positive ``self-bias'' and the effects of boundary conditions are discussed. The measured density decrease factor of 18 at 100 W RF power across the expansion region yields a higher ion acceleration and agrees with a conservation-of-flux calculation. The effect of lower flow rates and pressures, higher RF powers and magnetic field strength dependence on the ion beam acceleration, plasma potential, electron density and temperature are further explored. The axial ion velocity distribution function and temperatures at higher powers are observed by argon 668 nm laser induced fluorescence with density measurements by interferometry. The electron energy distribution and its possible non-Maxwellian tail are examined using optical emission spectroscopy (ADAS and Vlcek models).

Sung, Yung-Ta; Devinney, Michael; Scharer, John

2012-10-01

248

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

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.

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

249

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

250

Fresh Frozen Plasma in Pump Priming for Congenital Heart Surgery: Evaluation of Effects on Postoperative Coagulation Profiles Using a Fibrinogen Assay and Rotational Thromboelastometry  

PubMed Central

Purpose In this prospective study, the effects of fresh frozen plasma (FFP) included in pump priming for congenital heart surgery in infants and children on post-bypass coagulation profiles were evaluated. Materials and Methods Either 20% albumin (50-100 mL) or FFP (1-2 units) was added to pump priming for patients randomly allocated into control or treatment groups, respectively. Hematologic assays, including functional fibrinogen level, and rotational thromboelastometry (ROTEM®) were measured before skin incision (baseline), after weaning from cardiopulmonary bypass (CPB) and heparin reversal, and at 24 hours (h) in the intensive care unit (ICU). Results All the baseline measurements were comparable between the control and treatment groups of infants and children. After heparin reversal, however, significantly higher fibrinogen levels and less reduced ROTEM parameters, which reflect clot formation and firmness, were demonstrated in the treatment groups of infants and children. At 24 h in the ICU, hematologic assays and ROTEM measurements were comparable between the control and treatment groups of infants and children. Transfusion requirements, excluding FFP in pump prime, and postoperative bleeding were comparable between the control and treatment groups of infants and children. Conclusion Although clinical benefits were not clearly found, the inclusion of FFP in pump priming for congenital heart surgery in infants and children was shown to improve the hemodilution-related hemostatic dysfunction immediately after weaning from CPB and heparin reversal. PMID:23549826

Lee, Jong Wha; Yoo, Young-Chul; Park, Han Ki; Bang, Sou-Ouk; Lee, Ki-Young

2013-01-01

251

Disseminated Intravascular Coagulation  

MedlinePLUS

... page from the NHLBI on Twitter. What Is Disseminated Intravascular Coagulation? Disseminated intravascular coagulation (ko-ag-u-LA-shun), or DIC, is ... condition. Rate This Content: Next >> November 2, 2011 Disseminated Intravascular Coagulation Clinical Trials Clinical trials are research studies that ...

252

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)

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.

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

2014-12-01

253

Surface force measurements between titanium dioxide surfaces prepared by atomic layer deposition in electrolyte solutions reveal non-DLVO interactions: influence of water and argon plasma cleaning.  

PubMed

Surface force measurements between titania surfaces in electrolyte solutions have previously revealed an unexplained long-range repulsive force at high pH, not described by Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory. Here, the surface forces between titania surfaces produced by atomic layer deposition (ALD) and cleaned using a variety of methods have been measured to determine the influence of the cleaning protocol on the measured forces and test the hypothesis that water plasma cleaning of the surface results in non-DLVO forces at high pH. For argon plasma and water plasma cleaned surfaces, a diffuse double layer repulsion and van der Waals attraction is observed near the isoelectric point. At high pH, the force remained repulsive up until contact, and no van der Waals attraction or adhesion was observed. Differences in the measured forces are explained by modification of the surface chemistry during cleaning, which alters the density of charged groups on the surface, but this cannot explain the observed disagreement with DLVO theory at high pH. PMID:24548170

Walsh, Rick B; Evans, Drew; Craig, Vincent S J

2014-03-01

254

Influence of low energy argon plasma treatment on the moisture barrier performance of hot wire-CVD grown SiNx multilayers  

NASA Astrophysics Data System (ADS)

The reliability and stability are key issues for the commercial utilization of organic photovoltaic devices based on flexible polymer substrates. To increase the shelf-lifetime of these devices, transparent moisture barriers of silicon nitride (SiNx) films are deposited at low temperature by hot wire CVD (HW-CVD) process. Instead of the conventional route based on organic/inorganic hybrid structures, this work defines a new route consisting in depositing multilayer stacks of SiNx thin films, each single layer being treated by argon plasma. The plasma treatment allows creating smoother surface and surface atom rearrangement. We define a critical thickness of the single layer film and focus our attention on the effect of increasing the number of SiNx single-layers on the barrier properties. A water vapor transmission rate (WVTR) of 2 × 10-4 g/(m2·day) is reported for SiNx multilayer stack and a physical interpretation of the plasma treatment effect is given.

Majee, Subimal; Fátima Cerqueira, Maria; Tondelier, Denis; Geffroy, Bernard; Bonnassieux, Yvan; Alpuim, Pedro; Bourée, Jean Eric

2014-01-01

255

Charge-state and element-resolved ion energies in the cathodic arc plasma from composite AlCr cathodes in argon, nitrogen and oxygen atmospheres  

E-print Network

The energy distribution functions of ions in the cathodic arc plasma using composite AlCr cathodes were measured as a function of the background gas pressure in the range 0.5 to 3.5 Pa for different cathode compositions and gas atmospheres. The most abundant aluminium ions were Al$^{+}$ regardless of the background gas species, whereas Cr$^{2+}$ ions were dominating in Ar and N$_2$ and Cr$^{+}$ in O$_2$ atmospheres. The energy distributions of the aluminium and chromium ions typically consisted of a high energy fraction due to acceleration in the expanding plasma plume from the cathode spot and thermalised ions that were subjected to collisions in the plasma cloud. The fraction of the latter increased with increasing background gas pressure. Atomic nitrogen and oxygen ions showed similar energy distributions as the aluminium and chromium ions, whereas the argon and molecular nitrogen and oxygen ions were mainly thermalised. In addition to the positively charged metal and gas ions, negatively charged oxygen an...

Franz, Robert; Anders, André

2014-01-01

256

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

NASA Astrophysics Data System (ADS)

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.

Rincón, R.; Muñoz, J.; Calzada, M. D.

2015-01-01

257

Exposure of platelet membrane phosphatidylserine regulates blood coagulation  

Microsoft Academic Search

This article addresses the role of platelet membrane phosphatidylserine (PS) in regulating the production of thrombin, the central regulatory molecule of blood coagulation. PS is normally located on the cytoplasmic face of the resting platelet membrane but appears on the plasma-oriented surface of discrete membrane vesicles that derive from activated platelets. Thrombin, the central molecule of coagulation, is produced from

Barry R Lentz

2003-01-01

258

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

259

Bustling argon: biological effect.  

PubMed

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

Ye, Zhouheng; Zhang, Rongjia; Sun, Xuejun

2013-01-01

260

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

E-print Network

of Mr. J ~ M. Jose Jullienne were indispensable. The author extends his gratitude to Mr. A. B. Alter, chairman of his graduate committee for his capable guidance and interests. Bob Vandiver aided in the accumulation of experimental data, His labors... Discussion of Results VII Conclusions VIII Presentation of Data 20 24 26 33 35 References LIST OF FIGURES Figure Page Cathode Rear Plate Nozzle Flange 0 8 10 3A Collar and Cap Nozzle Schematic of Plasma Generator Energy Losses for Various...

Farquhar, Bannister Wells

2012-06-07

261

Preliminary investigation of a medium power argon radiofrequency capacitively coupled plasma as atomization cell in atomic fluorescence spectrometry of cadmium.  

PubMed

The single ring electrode radiofrequency capacitively coupled plasma torch (SRTr.f.CCP) operated at 275W, 27.12 MHz and Ar flow rate below 0.7 lmin(-1) was investigated for the first time as atomization cell in atomic fluorescence spectrometry (AFS) using electrodeless discharge lamps (EDL) as primary radiation source and charged coupled devices as detector. The signal to background ratio (SBR) and limit of detection for Cd determination by EDL-SRTr.f.CCP-AFS were compared to those obtained in atomic emission spectrometry using the same plasma torch. The detection limit in fluorescence was 4.3 ngml(-1) Cd compared to 65 ngml(-1) and 40 ngml(-1) reported in r.f.CCP-atomic emission (AES) equipped with single or double ring electrode. The lower detection limit in EDL-SRTr.f.CCP-AFS is due to a much better SBR in fluorescence. The limit of detection was also compared to those in atomic fluorescence with inductively coupled plasma (0.4 ngml(-1)), microwave plasma torch (0.25 ngml(-1)) and air-acetylene flame (8 ngml(-1)). The influence of light-scattering through the plasma and the secondary reflection of the primary radiation on the wall of the quartz tube on the analytical performance are discussed. The non-spectral matrix effects of Ca, Mg and easily ionized elements are much lower in EDL-SRTr.f.CCP-AFS compared to SRTr.f.CCP-AES. The new technique was applied in the determination of Cd in contaminated soils, industrial hazardous waste (0.4-370 mgkg(-1)) and water (113 microgl(-1)) with repeatability of 4-8% and reproducibility in the range of 5-12%, similar to those in ICP-AES. The results were checked by the analysis of a soil and water CRM with a recovery degree of 97+/-9% and 98+/-4%, for a confidence limit of 95%. The present EDL-SRTr.f.CCP-AFS is a promising technique for Cd determination in environmental samples. PMID:18761173

Frentiu, Tiberiu; Darvasi, Eugen; Senila, Marin; Ponta, Michaela; Cordos, Emil

2008-09-15

262

Density of atoms in Ar*(3p54s) states and gas temperatures in an argon surfatron plasma measured by tunable laser spectroscopy  

NASA Astrophysics Data System (ADS)

This study presents the absolute argon 1 s (in Paschens's notation) densities and the gas temperature, Tg, obtained in a surfatron plasma in the pressure range 0.65

10 mbar, for which the pressure broadening can no more be neglected. Tg 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 Tg at the tube center. In the studied pressure range, the Ar(4 s) atom densities are in the order of 1016-1018 m-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

Hübner, S.; Sadeghi, N.; Carbone, E. A. D.; van der Mullen, J. J. A. M.

2013-04-01

263

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

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

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

264

Disseminated intravascular coagulation (DIC)  

MedlinePLUS

Levi M. Disseminated intravascular coagulation. In: Hoffman R, Benz EJ Jr, Silberstein LE, et al., eds. Hematology: Basic Principles and Practice . 6th ed. Philadelphia, Pa: Elsevier Saunders; 2012:chap ...

265

Rheological approach to the analysis of blood coagulation in endothelial cell-coated tubes: Activation of the intrinsic reaction on the erythrocyte surface  

Microsoft Academic Search

Coagulation of blood in cultured endothelial cell-coated tubes was examined using a theological technique. Coagulation of recalcified, platelet-free plasma in contact with an endothelial cell monolayer did not occur within the experimental time period (more than 150 min). The endothelial cell surface did not activate the intrinsic coagulation reaction or the extrinsic coagulation reaction initiated by tissue factor. The time

S. Kawakami; M. Kaibara; Y. Kawamoto; K. Yamanaka

1995-01-01

266

Use of a nitrogen-argon plasma to improve adherence of sputtered titanium carbide coatings on steel  

NASA Technical Reports Server (NTRS)

Friction and wear experiments on 440-C steel surfaces that had been RF-sputtered with titanium carbide when a small percentage of nitrogen was added to the plasma were conducted. X-ray photoelectron spectroscopy and X-ray diffraction were used to analyze the resultant coatings. Results indicate that a small partial pressure of nitrogen (about 0.5%) markedly improves the adherence, friction, and wear properties when compared with coatings applied on sputter-etched oxidized surfaces or in the presence of a small oxygen partial pressure. The improvements are related to the formation of an interface containing a mixture of the nitrides of titanium and iron, which are harder than their corresponding oxides.

Brainard, W. A.; Wheeler, D. R.

1979-01-01

267

Experimental control of the solvent load of inductively coupled argon plasmas and effects of the chloroform plasma load on their analytical performance  

NASA Astrophysics Data System (ADS)

The solvent plasma load ( QSPL) of water, methanol and chloroform was established as a function of the liquid uptake rate ( QL) by using a continuous weighing method for recording the rate differences between the relevant liquid streams. The shape of the QL vs QSPL curves revealed that the liquid uptake rate is a parameter much too insensitive to serve as a criterion for assessing the stability of "organic" plasmas. The quantity "maximum tolerable solvent plasma load" is suggested as a more useful criterion. Effects of rf power, observation height and solvent plasma load on the properties of chloroform inductively coupled plasmas (ICPs) are reported. The measurement of the axial distribution of net line intensities of representative spectral lines showed that the behaviour of emission lines as to their "hardness" is essentially the same in ICPs loaded with chloroform or water. The chloroform plasma load was regulated by the use of a condenser of which the temperature was varied in a range between -50°C and +20°C. Analytical performance characteristics such as net line and background intensities, signal-to-background ratios, and relative standard deviations of the background signal are presented for ICPs with various chloroform loads. Two sets of experimental conditions were finally selected for simultaneous multielement analysis of chloroform solvent solutions, one with and one without aerosol cooling. In the case that aerosol cooling was applied, the detection limits were similar to those for aqueous plasmas. Without aerosol cooling the detection limits were up to an order of magnitude poorer. An attempt has been made to catagorize organic solvents on the basis of both volatility and their behaviour in ICP systems. For a better understanding of the consequences of solvent volatility in ICP-AES it is of importance to consider separately the properties that determine the volatility of liquids, viz. the evaporation rate and the saturation vapour pressure.

Maessen, F. J. M. J.; Kreuning, G.; Balke, J.

268

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)

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.

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

2012-06-01

269

Sepsis and Disseminated Intravascular Coagulation  

Microsoft Academic Search

Sepsis almost invariably leads to hemostatic abnormalities, ranging from insignificant laboratory changes to severe disseminated intravascular coagulation (DIC). There is compelling evidence from clinical and experimental studies that DIC is involved in the pathogenesis of microvascular dysfunction and contributes to organ failure. In addition, the massive and ongoing activation of coagulation, may deplete platelets and coagulation factors, which may in

Marcel Levi; Evert de Jonge; Tom van der Poll

2003-01-01

270

Fractal Coagulation Bruce E. Logan  

E-print Network

The Pennsylvania State University Email: blogan@psu.edu http://www.engr.psu.edu/ce/enve/logan.html #12;Net carbon sink Deep Ocean Marine snow Carbon cycledPhotic zone Global Carbon Cycling Sediments Atmosphere #12 Successful collisions & coagulation #12;Coagulation Theory ·Coagulation theory is quite old, dating back

271

Disseminated intravascular coagulation  

PubMed Central

Disseminated intravascular coagulation (DIC) is a reflection of an underlying systemic disorder which affects the coagulation system, simultaneously resulting in pro-coagulant activation, fibrinolytic activation, and consumption coagulopathy and finally may result in organ dysfunction and death. Though septicaemia is the most common cause of DIC, several other conditions can also lead to it. A diagnosis of DIC should be made only in the presence of a causative factor supported by repeated laboratory tests for coagulation profile and clotting factors. An effective scoring system helps to detect an overt DIC and a high score closely correlates with mortality. Treatment of DIC is aimed at combating the underlying disorder followed by supportive management. Low molecular weight heparin is advocated in special situations whereas anti-thrombin III and activated protein C are of doubtful value. Early diagnosis and prompt treatment backed by laboratory support can reduce the morbidity and mortality associated with it. The methodology of search for this review article involved hand search from text books and internet search using Medline (via PubMed) using key words DIC, thrombosis, fibrin degradation products, anti-thrombin and tissue factor for the last 25 years and also recent evidence-based reviews. PMID:25535423

Venugopal, A

2014-01-01

272

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)

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.

Roman, W. C.

1979-01-01

273

Change in blood coagulation indices as a function of the incubation period of plasma in a constant magnetic field. [considering heparin tolerance and recalcification  

NASA Technical Reports Server (NTRS)

The influence of a constant magnetic field (CMF) with a strength of 250 and 2500 oersteds on the recalcification reaction and the tolerance of plasma to heparin was studied as a function of the exposure time of the plasma to the CMF. The maximum and reliable change in the activation of the coagulatory system of the blood was observed after a 20-hour incubation of the plasma in a CMF. As the exposure time increased, the recalcification reaction changed insigificantly; the difference between the mean arithmetic of the experiment and control values was not statistically reliable. The tolerance of the plasma to heparin as a function of the exposure time to the CMF of the plasma was considerably modified, an was statistically reliable.

Yepishina, S. G.

1974-01-01

274

Chronic sleep deprivation markedly reduces coagulation factor VII expression  

PubMed Central

Chronic sleep loss, a common feature of human life in industrialized countries, is associated to cardiovascular disorders. Variations in functional parameters of coagulation might contribute to explain this relationship. By exploiting the mouse model and a specifically designed protocol, we demonstrated that seven days of partial sleep deprivation significantly decreases (?30.5%) the thrombin generation potential in plasma evaluated upon extrinsic (TF/FVIIa pathway) but not intrinsic activation of coagulation. This variation was consistent with a decrease (?49.8%) in the plasma activity levels of factor VII (FVII), the crucial physiologicalal trigger of coagulation, which was even more pronounced at the liver mRNA level (?85.7%). The recovery in normal sleep conditions for three days completely restored thrombin generation and FVII activity in plasma. For the first time, we demonstrate that chronic sleep deprivation on its own reduces, in a reversible manner, the FVII expression levels, thus influencing the TF/FVIIa activation pathway efficiency. PMID:20418241

Pinotti, Mirko; Bertolucci, Cristiano; Frigato, Elena; Branchini, Alessio; Cavallari, Nicola; Baba, Kenkichi; Contreras-Alcantara, Susana; Ehlen, J. Christopher; Bernardi, Francesco; Paul, Ketema N.; Tosini, Gianluca

2010-01-01

275

Overview of the coagulation system  

PubMed Central

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

Palta, Sanjeev; Saroa, Richa; Palta, Anshu

2014-01-01

276

Disseminated intravascular coagulation complicating urothelial malignancy.  

PubMed

Transitional cell carcinoma has rarely been reported to be associated with disseminated intravascular coagulation (DIC). We report a 55-year-old Chinese man who was diagnosed with transitional cell carcinoma with vertebral metastasis. He presented with severe anaemia and thrombocytopenia, and subsequent evaluation revealed features of DIC. Interestingly, he did not have fever, any localising symptoms or signs of infection. He was treated aggressively with transfusion of packed cells, platelets, intravenous vitamin K and fresh frozen plasma. Despite aggressive treatment, the coagulation abnormalities were resistant to correction. The patient continued to deteriorate and eventually died of cardiac arrest. This case illustrates that transitional cell carcinoma can also be associated with DIC, possibly due to the expression of certain unidentified procoagulant factors similar to the tissue factor responsible for DIC. PMID:22941143

Chadachan, Veerendra M; Lee, Siew Khow

2012-08-01

277

RADIATION KINETICS AND CHEMICAL REACTIVITY OF BARRIER DISCHARGES IN HUMID ARGON  

E-print Network

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

Boyer, Edmond

278

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

E-print Network

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 stronger due to other surface receptors involved in platelet adhesion. At the same time, the fibrin network

279

Thermophoretically Dominated Aerosol Coagulation  

NASA Astrophysics Data System (ADS)

A theory of aerosol coagulation due to size-dependent thermophoresis is presented. This previously overlooked effect is important when local temperature gradients are large, the sol population is composed of particles of much greater thermal conductivity than the carrier gas, with mean diameters much greater than the prevailing gas mean free path, and an adequate “spread” in sizes (as in metallurgical mists or fumes). We illustrate this via a population-balance analysis of the evolution of an initially log-normal distribution when this mechanism dominates ordinary Brownian diffusion.

Rosner, Daniel E.; Arias-Zugasti, Manuel

2011-01-01

280

ORIGINAL PAPER Effect of vegetable coagulant, microbial coagulant  

E-print Network

present on the surface of the casein micelles. However, the increase in cheese production, coupled between the cheeses. The vegetable coagulants showed higher intensity bands in the Pre-s- casein region, which was related to higher s-casein proteolytic rates. The use of vegetable coagulants should enable

Paris-Sud XI, Université de

281

Glial reactions to argon laser photocoagulation injury in rabbit and rat retinas  

Microsoft Academic Search

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

Martin F. Humphrey; Yi Chu; Claudia Sharp; Stephen Moore; Krishna Mann; Piroska Rakoczy; Ian J. Constable

1996-01-01

282

Spatial localization of bacteria controls coagulation of human blood by ‘quorum acting’  

PubMed Central

Blood coagulation often accompanies bacterial infections and sepsis and is generally accepted as a consequence of immune responses. Though many bacterial species can directly activate individual coagulation factors, they have not been shown to directly initiate the coagulation cascade that precedes clot formation. Here we demonstrated, using microfluidics and surface patterning, that the spatial localization of bacteria substantially affects coagulation of human and mouse blood and plasma. Bacillus cereus and Bacillus anthracis, the anthrax-causing pathogen, directly initiated coagulation of blood in minutes when bacterial cells were clustered. Coagulation of human blood by B. anthracis required secreted zinc metalloprotease InhA1, which activated prothrombin and factor X directly (not via factor XII or tissue factor pathways). We refer to this mechanism as ‘quorum acting’ to distinguish it from quorum sensing—it does not require a change in gene expression, it can be rapid and it can be independent of bacterium-to-bacterium communication. PMID:19031531

Kastrup, Christian J; Boedicker, James Q; Pomerantsev, Andrei P; Moayeri, Mahtab; Bian, Yao; Pompano, Rebecca R; Kline, Timothy R; Sylvestre, Patricia; Shen, Feng; Leppla, Stephen H; Tang, Wei-Jen; Ismagilov, Rustem F

2009-01-01

283

[An experimental study of the coagulating properties of a laser beam applied to fix titanium prostheses of auditory ossicles with the use of platelet-rich plasma].  

PubMed

The displacement of prostheses of auditory ossicles at the concluding stage of surgery and in the early postoperative period is one of the factors influencing the functional outcome of stapedoplasty. The objective of the present experimental study was to estimate the effectiveness of the use of platelet-rich plasma as an alloy for the laser welding in order to improve fixation of titanium prostheses employed in ossiculoplastic surgery. The results of a series of experiments undertaken to assess the possibility of stabilization of titanium prostheses in the desired position with the help of laser welding indicate that this technique with the use of platelet-rich plasma as an alloy may be a reliable method for the fixation of the reconstructed chain of ossicles in the desired position. PMID:24300758

Semenov, V F; Semenov, F V

2013-01-01

284

Coagulation of sheep intestinal and prefemoral lymph.  

PubMed

We have determined the most suitable method for the automated analysis of the clotting parameters in sheep intestinal and prefemoral lymph as defined by the Activated Partial Thromboplastin Times (APTT; measure of intrinsic coagulation pathway) and the Prothrombin Times (PT; measure of extrinsic coagulation pathway). As opposed to optical density systems, the use of a Fibro-System Fibrometer was found to provide the most consistent assessment of coagulation with the endpoint being the time to fibrin strand formation. We measured APTT in sheep intestinal and prefemoral lymph of 59.78 +/- 7.69 seconds and 51.03 +/- 10.49 seconds respectively. These values were more prolonged than those obtained from sheep blood plasma but only in the case of intestinal lymph were the differences significant (p less than 0.025). Human blood APTT values were significantly less than both sheep blood (p less than 0.05) and sheep intestinal (p less than 0.001) and prefemoral lymph (p less than 0.01). PT values were found to be 21.56 +/- 1.14 seconds in intestinal and 22.00 +/- 1.88 seconds in prefemoral lymph. These values were also significantly greater than those obtained from sheep blood (both p less than 0.001). Human blood PTs were significantly less than both sheep blood (p less than 0.001) and intestinal and prefemoral lymph (both p less than 0.001). Measurement of APTT and PT values in intestinal lymph and PT determinations in prefemoral lymph were not affected by storage in the refrigerator or freezer. There was some indication that APTT values in prefemoral samples were susceptible to storage artifacts; however, the differences in coagulation times were not significant. PMID:3221717

Hanley, C A; Johnston, M G; Nelson, W

1988-06-01

285

Global coagulation in myeloproliferative neoplasms.  

PubMed

In spite of their recognized risk of thrombosis, patients with myeloproliferative neoplasms (MPN) show little or no abnormalities of traditional coagulation tests, perhaps because these are unable to represent the balance between pro- and anticoagulants nor the effect of platelets and blood cells. We investigated whether global tests such as thrombin generation in platelet-rich plasma (PRP) or thromboelastometry in whole blood were able to detect signs of procoagulant imbalance in MPN. The endogenous thrombin potential (ETP) of 111 patients and 89 controls was measured in PRP with platelet count adjusted to the original patient- or control-count. Testing was performed with and without thrombomodulin (the physiological protein C activator) and results were expressed as ETP ratios (with/without thrombomodulin). High ETP ratios reflect resistance to thrombomodulin and were taken as indexes of procoagulant imbalance. Patients were also investigated by thromboelastometry that provides such parameters as the clot formation time (CFT) and maximal clot firmness (MCF). Short CFT or high MCF were taken as indexes of procoagulant imbalance. ETP ratios were higher in patients than in controls and were directly correlated with platelet counts and inversely with the plasma levels of free protein S, protein C and antithrombin. Patients on hydroxyurea had lower ETP ratios than those on other treatments. CFT was shorter and MCF was greater in patients than controls; CFT and MCF were correlated with platelet counts. In conclusion, patients with MPN display a procoagulant imbalance detectable by thrombin generation and thromboelastometry. These tests might be useful in the frame of clinical trials to assess their association with the occurrence of thrombosis and with the effect of therapeutic strategies in MPN. PMID:23820940

Tripodi, Armando; Chantarangkul, Veena; Gianniello, Francesca; Clerici, Marigrazia; Lemma, Laura; Padovan, Lidia; Gatti, Loredana; Mannucci, Pier Mannuccio; Peyvandi, Flora

2013-12-01

286

Coagulation defects resulting from ambient temperature-induced hypothermia.  

PubMed

Ambient temperature-induced hypothermia noted in trauma patients is frequently accompanied by a bleeding diathesis despite "laboratory normal" coagulation values. To document this impression, the following experiment was conducted. Coagulation studies and platelet function studies were performed in ten minipigs during induced whole body hypothermia (40 degrees C to 34 degrees C) and rewarming. Cooling was achieved in 2 to 3 hours and rewarming took 4 to 5 hours. In addition, similar coagulation and platelet function studies were conducted on plasma samples from the same animals that were cooled and then rewarmed in a water bath. Platelet counts and function as measured by Sonoclot analysis and aggregation did not decrease significantly with hypothermia in either model. Plasma cooled in a water bath demonstrated abnormal PT and aPTT (p < 0.001). Whole body hypothermia demonstrated abnormal bleeding time and PT (p < 0.001). Ambient temperature-induced hypothermia produced significant coagulation defects in a porcine model. Some of the coagulation defects were most pronounced during rewarming. PMID:8189462

Staab, D B; Sorensen, V J; Fath, J J; Raman, S B; Horst, H M; Obeid, F N

1994-05-01

287

Microfluidics and Coagulation Biology  

PubMed Central

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

Colace, Thomas V.; Tormoen, Garth W.

2014-01-01

288

[Disseminated intravascular coagulations].  

PubMed

Disseminated intravascular coagulation (DIC) syndromes can be defined as the formation of fibrin deposits within the microcirculation, occurring in definite clinical situations. Their biological counterpart is a consumption coagulopathy. The clinical profiles of DIC have been well known for decades, are multiform and range from latency to overwhelming haemorrhagic diatheses, including also characteristic but rare situations, such as purpura fulminans, acral cyanosis and pictures resembling thrombotic thrombocytopenic purpura or haemolytic-uraemic syndrome. Biological tests of DIC show a consumption coagulopathy, displayed on the standard haemostasis sheet; along with signs of paracoagulation and/or of secondary fibrinolysis (FDP). New tests have recently been introduced: D-dimers are specific and sensible; Antithrombin-III, protein C and alpha 2-antiplasmin also can sometimes be useful. The knowledge of the pathophysiology of DIC has made advances with passing years. Fibrin deposits may be non-occlusive, and indeed they are swiftly removed by a secondary fibrinolysis. Except in very rare situations, such as those leading to a cortical renal necrosis, and perhaps in some ARDS, there is little evidence relating DIC to organ failure syndromes. Moreover, there is no clear relationship between the severity of the consumption coagulopathy and the prognosis. For instance, the mortality is much lower in abruptio placentae, where the coagulopathy is very severe, than in septic shock, where it is usually moderate. In septic shock, the disorders of haemostasis were related initially to a platelet activation, then to an activation of the contact system (releasing kinins and triggering complement cascade), and nowadays to the activation of the extrinsic coagulation system. The treatment of DIC is mainly the treatment of its cause. Indications for heparin therapy should be strictly limited to a few exceptional circumstances. When haemorrhagic diathesis threatens, FPC and/or platelet transfusion may be indicated. Aprotinin can be useful in rare cases of overwhelming secondary fibrinolysis. Trials with antithrombin-III or C1-esterase inhibitors are in progress. PMID:9005011

Amstutz, P; Moyo, J S

1996-01-01

289

Thermophoretically modified aerosol Brownian coagulation  

NASA Astrophysics Data System (ADS)

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].

Arias-Zugasti, Manuel; Rosner, Daniel E.

2011-08-01

290

Surface-Mediated Control of Blood Coagulation: The Role of Binding Site Densities and Platelet Deposition  

Microsoft Academic Search

A mathematical model of the extrinsic or tissue factor (TF) pathway of blood coagulation is formulated and results from a computational study of its behavior are presented. The model takes into account plasma-phase and surface-bound enzymes and zymogens, coagulation inhibitors, and activated and unactivated platelets. It includes both plasma-phase and membrane-phase reactions, and accounts for chemical and cellular transport by

Andrew L. Kuharsky; Aaron L. Fogelson

2001-01-01

291

Depleted Argon from Underground Sources  

SciTech Connect

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.

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

292

Cosmic dust synthesis by accretion and coagulation  

NASA Technical Reports Server (NTRS)

The morphology of grains grown by accretion and coagulation is revaled by a new laboratory method of synthesizing cosmic dust analogs. Submicron carbon particles, grown by accretion of carbon atoms from a gas, have a spherical shape with a cauliflower-like surface and an internal micro-structure of radial columns. This shape is probably common for grains grown by accretion at a temperature well below the melting point. Coagulated grains, consisting of spheres that collided to form irregular strings, were also synthesized. Another shape we produced had a bumpy non- spherical morphology, like an interplanetary particle collected in the terrestrial stratosphere. Besides these isolated grains, large spongy aggregates of nanometer-size particles were also found for various experimental conditions. Grains were synthesized using ions to sputter a solid target, producing an atomic vapor at a low temperature. The ions were provided by a plasma, which also provided electrostatic levitation of the grains during their growth. The temporal development of grain growth was studied by extinguishing the plasma after various intervals.

Praburam, G.; Goree, J.

1995-01-01

293

RHEOMETRY FOR BLOOD COAGULATION STUDIES  

E-print Network

This review considers some of the various rheometrical approaches that have been adopted to study blood coagulation, with special reference to the rheological assessment of clotting time and studies of the evolution of viscoelasticity during the course of fibrin polymerization and cross-linking. A common feature of many of these studies is that they attempt to detect a liquid-to-solid transition during coagulation and the significance of the Gel Point in blood coagulation studies is discussed. Coagulation studies based on various forms of shear viscosity measurements and complex shear modulus measurements are considered, the latter being based principally on instruments such as the various controlled stress and controlled strain rheometers. Also considered is the long established technique of thromboelastography, while several emerging techniques are described. The latter include damped oscillation rheometry, various forms of wave propagation measurements and other, less widely used techniques such as free oscillation rheometry, quartz crystal microbalance measurements and surface plasmon resonance.

P. A. Evans; K. Hawkins; P. R. Williams

294

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, ...

295

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

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

C. T. Bolliger; T. G. Sutedja; J. Strausz; L. Freitag; Lungenklinik Hemer

296

Characteristics of atmospheric-pressure, radio-frequency glow discharges operated with argon added ethanol  

Microsoft Academic Search

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

Wen-Ting Sun; Guo Li; He-Ping Li; Cheng-Yu Bao; Hua-Bo Wang; Shi Zeng; Xing Gao; Hui-Ying Luo

2007-01-01

297

A comparative study of coagulation systems in newborn animals.  

PubMed

Appropriate animal experimentation can enhance our understanding of thrombotic and hemorrhagic problems in the human neonate. Which newborn animal species' coagulation system most closely resembles the human neonate is unknown. The objective of the study was to assess the newborn coagulation system in four animal species and compare them with the human neonate. Blood samples were drawn on days 1 and 7 of life from lambs (n = 10), piglets, (n = 12), rabbit pups (n = 12), and beagle pups (n = 7). Coagulation screening tests, specific factor assays, and specific inhibitors of the coagulation system were measured. All factor assays were expressed as a percent of the respective species pooled adult plasma. The results from the animals were compared to normal values from our laboratory for healthy full-term infants. The coagulation systems of all species tested, except the rabbit pup, were immature at birth with most factor levels being lower than the adult of their species. The coagulation systems were influenced by the postnatal age of the animal and the factor levels reached adult values in fewer days relative to the human. The coagulation system for the piglet most closely approximated the human neonate. The shared characteristics were prolonged screening tests, increased factor VIII:C, generally low levels for the contact and vitamin K-dependent factors, and low antithrombin III levels relative to the adult. The beagle pup also showed many similar characteristics but in contrast to the human neonate factor VIII:C and V were low on day 1 of life and prekallikrein was not measurable in the adult or newborn beagle.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3774411

Massicotte, P; Mitchell, L; Andrew, M

1986-10-01

298

Effects of the Length of a Cylindrical Solid Shield on the Entrainment of Ambient Air into Turbulent and Laminar Impinging Argon Plasma Jets  

Microsoft Academic Search

When materials processing is conducted in air surroundings by use of an impinging plasma jet, the ambient air will be entrained\\u000a into the materials processing region, resulting in unfavorable oxidation of the feedstock metal particles injected into the\\u000a plasma jet and of metallic substrate material. Using a cylindrical solid shield may avoid the air entrainment if the shield\\u000a length is

Hai-Xing Wang; Xi Chen; Wenxia Pan

2008-01-01

299

One-step argon/nitrogen binary plasma jet irradiation of Li4Ti5O12 for stable high-rate lithium ion battery anodes  

NASA Astrophysics Data System (ADS)

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).

Lan, Chun-Kai; Chuang, Shang-I.; Bao, Qi; Liao, Yen-Ting; Duh, Jenq-Gong

2015-02-01

300

Thermophysical properties of argon  

SciTech Connect

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)

Jaques, A.

1988-02-01

301

Influence of argon plasma on the deposition of Al2O3 film onto the PET surfaces by atomic layer deposition  

PubMed Central

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

2013-01-01

302

Argon frost continuous cryopump for fusion applications  

SciTech Connect

A cryopumping system based on the snail continuous cryopump concept is being developed for fusion applications under a DOE SBIR grant. The primary pump is a liquid helium cooled compound pump designed to continuously pump and fractionate deuterium/tritium and helium. The D/T pumping stage is a 500 mm bore cryocondensation pump with a nominal pumping speed of 45,000 L/s. It will be continuously regenerated by a snail regeneration by head every 12 minutes. Continuous regeneration will dramatically reduce the vulnerable tritium inventory in a fusion reactor. Operating at an inlet pressure of 1 millitorr, eight of these pumps could pump the projected D/T flow in the ITER CDA design while reducing the inventory of tritium in the pumping system from 630 to 43 grams. The helium fraction will be pumped in a compound argon frost stage. This stage will also operate continuously with a snail regeneration head. In addition the argon spray head will be enclosed inside the snail, thereby removing gaseous argon from the process chamber. Since the cryocondensation stage will intercept over 90% of the D/T/H steam, a purified stream from this stage could be directly reinjected into the plasma as gas or pellets, thereby bypassing the isotope separation system and further simplifying the fuel cycle. Experiments were undertaken in Phase I which demonstrated continuous cryosorption pumping of hydrogen on CO{sub 2} and argon frosts. The pumping system and its relevance to fusion reactor pumping will be discussed.

Foster, C.A.; McCurdy, H.C.

1993-12-01

303

Characteristics of atmospheric-pressure, radio-frequency glow discharges operated with argon added ethanol  

NASA Astrophysics Data System (ADS)

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.

Sun, Wen-Ting; Li, Guo; Li, He-Ping; Bao, Cheng-Yu; Wang, Hua-Bo; Zeng, Shi; Gao, Xing; Luo, Hui-Ying

2007-06-01

304

Characteristics of atmospheric-pressure, radio-frequency glow discharges operated with argon added ethanol  

SciTech Connect

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 {alpha}-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.

Sun Wenting; Li Guo; Li Heping; Bao Chengyu; Wang Huabo; Zeng Shi; Gao Xing; Luo Huiying [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); School of Public Health and Family Medicine, Capital University of Medical Sciences, Beijing 100069 (China); Beijing Center for Diseases Control and Prevention, Beijing 100013 (China)

2007-06-15

305

Threshold Response of Initiation of Blood Coagulation by Tissue Factor in Patterned Microfluidic Capillaries Is Controlled by Shear Rate  

Microsoft Academic Search

Objective—Blood flow is considered one of the important parameters that contribute to venous thrombosis. We quantitatively test the relationship between initiation of coagulation and shear rate and suggest a biophysical mechanism to understand this relationship. Methods and Results—Flowing human blood and plasma were exposed to cylindrical surfaces patterned with patches of tissue factor (TF) by using microfluidics. Initiation of coagulation

Feng Shen; Christian J. Kastrup; Ying Liu; Rustem F. Ismagilov

2010-01-01

306

Interaction of Angiotensin with Disseminated Intravascular Coagulation  

PubMed Central

Because of the importance of the renin-angiotensin system in renal homeostatic mechanisms, the effect of angiotensin administration upon disseminated intravascular coagulation has been studied in rabbits. An infusion of angiotensin II (0.1 ?g/kg/min for 2 hours) produced neither histologic abnormalities in the kidneys nor an elevation of creatinine. After an infusion of thrombin (2.0 units/kg/min for 2 hours) only 3 of 10 rabbits, when sacrified 24 hours later, showed histologic lesions comprised of occasional fibrin thrombi and foci of tubular necrosis. Creatinine levels did not rise. In contrast, the combination of angiotensin and thrombin resulted in renal lesions in 12 of 14 animals. Four had frank cortical necrosis, while combinations of tubular necrosis, glomerular thrombosis and segmental glomerular infarction occurred in the others, together with elevated creatinine levels. Blockade of ?-adrenoreceptors with phenoxybenzamine in 12 animals did not prevent either these histologic changes or creatinine elevation, showing that the effect of angiotensin was independent of ?-adrenoreceptor stimulation. The synergistic interaction between angiotensin and disseminated intravascular coagulation was not explained by differences in the consumption of plasma fibrinogen but apparently was due to localization of fibrin thrombi within glomerular capillaries by the vasomotor actions of angiotensin, as has previously been shown to occur with ?-adrenoreceptor simulation. Such a mechanism might contribute to renal glomerular deposition of fibrin in acute ischemic renal failure. ImagesFig 2Fig 3Fig 1 PMID:4352549

Whitaker, Alan N.; Bunce, Ian; Nicoll, Peter; Dowling, Susanne V.

1973-01-01

307

Tissue Factor in Coagulation: Which? Where? When?  

PubMed Central

Tissue factor (TF) is an integral membrane protein, normally separated from the blood by the vascular endothelium, which plays a key role in the initiation of blood coagulation. With a perforating vascular injury, TF becomes exposed to blood and binds plasma factor VIIa. The resulting complex initiates a series of enzymatic reactions leading to clot formation and vascular sealing. In some pathologic states, circulating blood cells express TF as a result of exposure to an inflammatory stimulus leading to intravascular clotting, vessel occlusion and thrombotic pathology. Numerous controversies have arisen related to the influence of structural features of TF, its presentation and its function. There are contradictory reports about the synthesis and presentation of TF on blood cells and the presence (or absence) of functionally active TF circulating in normal blood either on microparticles or as a soluble protein. In this review we discuss TF structure-function relationships and the role of TF during various phases of the blood coagulation process. We also highlight controversies concerning the expression/presence of TF on various cells and in blood in normal and pathologic states. PMID:19592470

Butenas, Saulius; Orfeo, Thomas; Mann, Kenneth G.

2009-01-01

308

The role of platelets in blood coagulation—effects of platelet agonists and GPIIb\\/IIIa inhibitors studied by free oscillation rheometry  

Microsoft Academic Search

We have studied the contribution of platelets to the coagulation of plasma and the effects of activation or inhibition of platelets on the coagulation process in unanticoagulated fresh whole blood (subsequently termed native blood). For this purpose, we have used a free oscillation rheometer (FOR), the ReoRox4, a new instrument that enables noninvasive viscoelastic measurements of clot formation in plasma

Sofia Ramström; Mats Rånby; Tomas L. Lindahl

2002-01-01

309

Analysis of the Mid-Infrared Spectrum of the Exhaust Gas From an Atmospheric Pressure Plasma Jet (APPJ) Working With an Argon–Air Mixture  

Microsoft Academic Search

The mid-infrared (IR) absorption spectrum of the exhaust gas of an atmospheric pressure plasma jet operated in Ar with the admixture of 0.1% of air has been monitored in the spectral region from 4000 to 750 cm-1. The absorption features of CO2, CO, NO, NO2, N2O, HNO2, and HNO3 were identified using a Fourier transform IR spectrometer combined with a

Andrei V. Pipa; Jürgen Ropcke

2009-01-01

310

Effects of the shielding cylinder and substrate on the characteristics of an argon radio-frequency atmospheric glow discharge plasma jet  

Microsoft Academic Search

With unique features of low breakdown voltages, large and uniform discharge areas and high concentrations of chemically reactive species, radio-frequency, atmospheric-pressure glow discharge (rf APGD) plasma sources produced with bare-metallic electrodes have shown promising prospects in the field of materials processing. In this paper, the spatial distributions (i.e., the directly measured integrated axial distribution and the radial distribution by using

Guo Li; Pei-Si Le; He-Ping Li; Cheng-Yu Bao

2010-01-01

311

Argon ion pollution of the magnetosphere  

NASA Technical Reports Server (NTRS)

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.

Lopez, R. E.

1985-01-01

312

An investigation into an indigenous natural coagulant  

Microsoft Academic Search

Coagulants play an important role in the treatment or water and waste water, and the treatment and disposal of sludge. Aluminum sulfate, alum, is the common chemical coagulant used in the process of coagulation here in Iraq and other middle eastern countries. Recently there have been many rumours of the possible link between high levels of residual aluminum and several

Edham M. Shokralla

1996-01-01

313

CONTROLLING COAGULATION DYSREGULATION IN XENOTRANSPLANTATION  

PubMed Central

Purpose of review Deletion of the ?1,3-galactosyltransferase (GalT) gene in pigs has removed a major xenoantigen but has not eliminated the problem of dysregulated coagulation and vascular injury. Rejecting GalT KO organ xenografts almost invariably show evidence of thrombosis and platelet sequestration, and primate recipients frequently develop consumptive coagulopathy (CC). This review examines recent findings that illuminate potential mechanisms of this current barrier to successful xenotransplantation. Recent findings The coagulation response to xenotransplantation differs depending on the type of organ and quite likely the distinct vasculatures. Renal xenografts appear more likely to initiate CC than cardiac xenografts, possibly reflecting differential transcriptional responses. Liver xenografts induce rapid and profound thrombocytopenia resulting in recipient death within days due to bleeding; ex vivo data suggest that liver endothelial cells and hepatocytes are responsible for platelet consumption by a coagulation-independent process. It has been proposed that expression of recipient tissue factor on platelets and monocytes is an important trigger of CC. Finally, pigs transgenic for human anticoagulants and antithrombotics are slowly but surely coming on line, but have not yet been rigorously tested to date. Summary Successful control of coagulation dysregulation in xenotransplantation may require different combinatorial pharmacological and genetic strategies for different organs. PMID:21415824

Cowan, Peter J.; Robson, Simon C.; d’Apice, Anthony J.F.

2011-01-01

314

Dielectronic recombination on heliumlike argon  

Microsoft Academic Search

We have used the electron-energy dependence of yields of heliumlike and lithiumlike argon ions from the Kansas State University electron-beam ions source (EBIS) to measure the ratio of the cross section for Î {ital n}=1 dielectronic recombination of heliumlike argon to that for electron ionization of lithiumlike argon. By normalizing to the latter cross section we obtain absolute dielectronic recombination

R. Ali; C. P. Bhalla; C. L. Cocke; M. Stockli

1990-01-01

315

Dielectronic recombination on heliumlike argon  

SciTech Connect

We have used the electron-energy dependence of yields of heliumlike and lithiumlike argon ions from the Kansas State University electron-beam ions source (EBIS) to measure the ratio of the cross section for {Delta} {ital n}=1 dielectronic recombination of heliumlike argon to that for electron ionization of lithiumlike argon. By normalizing to the latter cross section we obtain absolute dielectronic recombination cross sections and find good agreement with theoretical calculations for the lower-energy resonances.

Ali, R.; Bhalla, C.P.; Cocke, C.L.; Stockli, M. (J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, Kansas 66506 (USA))

1990-02-05

316

The Argon Geochronology Experiment (AGE)  

NASA Technical Reports Server (NTRS)

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.

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

317

Isentropic compression of argon  

SciTech Connect

The compression was done in an MC-1 flux compression (explosive) generator, in order to study the transition from an insulator to a conductor. Since conductivity signals were observed in all the experiments (except when the probe is removed), both the Teflon and the argon are becoming conductive. The conductivity could not be determined (Teflon insulation properties unknown), but it could be bounded as being {sigma}=1/{rho}{le}8({Omega}cm){sub -1}, because when the Teflon breaks down, the dielectric constant is reduced. The Teflon insulator problem remains, and other ways to better insulate the probe or to measure the conductivity without a probe is being sought.

Veeser, L.R.; Ekdahl, C.A.; Oona, H. [and others

1997-06-01

318

The Coagulation System and Angiogenesis  

Microsoft Academic Search

In 1865, Armand Trousseau recognized the relationship between an activated coagulation system and malignancy [1]. He suggested\\u000a that patients presenting with idiopathic venous thrombosis might be harboring an occult cancer. Numerous recent studies have\\u000a also demonstrated an increased odds ratio of patients with idiopathic venous thromboembolic disease having an occult malignancy\\u000a (i.e. [2]). Venous thromboembolic disease (VTE) is the second

Gurinder Sidhu; Gerald A. Soff

319

[Coagulation factor mutations and thrombosis].  

PubMed

The coagulation system is governed by a subtle balance between clotting activators and inhibitors. Many genes can contribute to the overall phenotype, and polymorphisms may act to up regulate or down regulate the generation of thrombin, the coagulation-key enzyme. An increase in coagulation factor (gain function) or/and a decrease in coagulation inhibitors (loss of function) may favor venous thromboembolism (VTE). It has been observed since a long time that VTE may be a familial disease, but it was only in 1965 that Egeberg published the first case of inherited antithrombin (AT) deficiency. This was followed by similar reports of protein C (PC) and protein S (PS) deficiencies. Hereditary thrombophilia was thus initially considered as a rare monogenic disorder with incomplete penetrance. AT, PC and PS deficiencies are due to multiple and mostly private mutations of the corresponding genes. Most patients are heterozygous and experience VTE at adult age. Homozygosity associated with severe thrombosis at birth has been observed in newborns with undetectable PC or PS concentrations. The discovery of factor (F) V Leiden and F2 g.20210 G>A, two gain of function mutations, challenged the view of thrombophilia as a rare monogenic disorder. FV Leiden and F2 g.20210 G>A are due to a founder effect and affect populations of European descent with frequencies at 5% and 3% respectively. These two mutations are moderate of risk factor for thrombosis and paved the way for gene-gene and gene-environment interactions. Patients carrying more than one genetic risk factor are at higher risk to develop VTE. The exposition to acquired risk factors such as estrogen based oral contraception may also have a synergistic effect favoring thrombosis in patients with FV Leiden or other genetic risk factors. PMID:17101102

Aiach, Martine; Alhenc-Gelas, Martine; Borgel, Delphine; Emmerich, Joseph; Gandrille, Sophie; Picard, Véronique

2006-11-01

320

Thermophysical properties of multi-shock compressed dense argon  

SciTech Connect

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.

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

321

Argon Welding Inside A Workpiece  

NASA Technical Reports Server (NTRS)

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.

Morgan, Gene E.

1988-01-01

322

[POCT in coagulation. Quality assurance].  

PubMed

In the last years several point of care testing (POCT) systems used for coagulation parameters have been developed and became daily routine. As for other POCT applications (e. g. blood gas analysis) there is a need for user education and continuous improvement of quality assurance. For some POCT coagulation systems a comprehensive quality management has not been established yet. According to the feasibility and availability of control material and system self control each POCT coagulation method described in this article has a varying concept of quality management. Besides a high quality standard in manufacturing systems, devices and reagents the education of the user and the automatic self control of the instrument as well as the application of electronic and/ or liquid control samples contribute to the total quality assurance. Even if a "like versus like" control material is not available a comprehensive quality management should be implemented in daily routine concerning pre-analytic as well as technical and post-analytic criteria. Anyway to do nothing as the available control material seems to be not suitable is a bad decision. PMID:20454752

Spannagl, Michael; Dick, A; Junker, R

2010-05-01

323

Bleeding and coagulation disorders in the elderly.  

PubMed

Ageing does not bring with it any major changes in the coagulation or fibrinolytic proteins or platelets. It does bring a greater burden of disease, with less reserves, and so when haemorrhage occurs in the elderly it has more serious consequences. The cause of a bleeding diathesis can usually be determined after a careful history, and examination of the patient followed by simple tests--the platelet count, blood film, bleeding time, prothrombin time, partial thromboplastin time, thrombin time, fibrin degradation products and the euglobulin clot lysis time. Other confirmatory tests, assays and inhibitor titres, will seal the diagnosis. Treatment is mainly directed at removing the underlying cause, if possible, and remedying the defect, with platelet transfusion, fresh frozen plasma or factor concentrates. These treatments will not be effective where there is an inhibitor or antibody present; steroids, splenectomy (for ITP), plasma exchange or immunosuppression are needed. Two major advances have occurred in the early 1980s. One has been the introduction of high-dose intravenous immunoglobulin in the management of ITP, although worries remain about thrombotic events in elderly patients. The other is the spreading use of DDAVP, originally introduced for von Willebrand's disease and mild haemophilia, and now finding a role in uraemia and with cardiopulmonary bypass. Drugs are a significant and potentially preventable cause of bleeding in the elderly. The most frequent problems arise with anticoagulants. The risk of interactions increase with the number of other medications which are prescribed. PMID:3322449

Copplestone, J A

1987-06-01

324

Laser-induced fluorescence observations of a multipolar argon discharge  

SciTech Connect

Observations carried out with a laser-induced fluorescence diagnostic on several configurations of a multipolar discharge are presented. This diagnostic allows very accurate measurements of the ion velocity distribution function in the argon plasma and reveals the presence of double-hump velocity distribution functions due to ion acceleration in the static plasma potential and ion reflection on a multipolar magnetic field. These observations give a new insight to ion temperature and ion drifts inside the device.

Bachet, G.; Cherigier, L.; Carrere, M.; Doveil, F. (Equipe Turbulence Plasma de l'URA 773 du CNRS et de l'Universite de Provence, Institut Mediterraneen de Technologie, F13451 Marseille Cedex 13 (France))

1993-08-01

325

Insights into platelet-based control of coagulation.  

PubMed

The coagulation process is activated by tight control mechanisms, in which platelets play prominent and unique roles. In thrombosis and hemostasis, activated platelets regulate the coagulation system in various ways: by exposing a phosphatidylserine surface for thrombin formation, by supporting fibrin formation, and by regulating the retraction of a fibrin clot. In this review we discuss the involvement of platelet receptors, other membrane proteins, downstream signaling proteins, cytoskeleton-linked proteins and plasma proteins in these procoagulant functions. Studies with both genetically modified mice and pharmacological inhibitors indicate that, for collagen-adhered platelets, in part common signaling pathways lead to phosphatidylserine exposure, generation of thrombin and fibrin, and retraction of the fibrin clot. However, prolonged Ca(2+) elevation leads to thrombin generation, whereas integrin-dependent signaling stimulates fibrin clot retraction. Contact-dependent signaling pathways, triggered by homotypic platelet-platelet interactions, act in particular via the integrin route. PMID:24862135

de Witt, Susanne M; Verdoold, Remco; Cosemans, Judith M E M; Heemskerk, Johan W M

2014-05-01

326

Depleted argon from underground sources  

SciTech Connect

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.

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

327

Study of fluid mechanical helium argon ion laser  

NASA Technical Reports Server (NTRS)

An approach to an argon ion laser based on gasdynamic techniques is presented. Improvement in efficiency and power output are achieved by eliminating high heat rejection problems and plasma confinement of the seal-off conventional lasers. The process of producing population inversion between the same energy levels, as in the conventional argon ion laser, has been divided into two phases by separating each other from the processes of ionization and subsequent excitation. Line drawings and graphs are included to amplify the theoretical presentation.

1972-01-01

328

Characterization of atmospheric pressure microplasma produced from argon and a mixture of argon-ethylenediamine  

NASA Astrophysics Data System (ADS)

A non-thermal atmospheric pressure microplasma generated from pure argon (Ar) and a mixture of argon-ethylenediamine vapors (Ar/EDA) has been characterized in this study. A sinusoidal power supply operating at 30 kHz was used to excite microplasma in a rectangular borosilicate glass capillary (4×0.4 mm). The monomer EDA was mixed with Ar in order to perform plasma polymerization inside the microchannel. The analyses were made by measuring spectroscopic and electrical parameters of the discharge. The effects of EDA mixing on plasma parameters such as electron, excitation and rotational temperatures during the process of surface coating of the microchannel were investigated. These parameters play an important role in the deposition process. The plasma temperatures estimated through spectroscopic measurement were found in the sequence Te>Texc>Tvib>Trot, which indicated the non-thermal characteristics of the proposed DBD microplasma. The parameters of the Ar discharge were also numerically computed using plasma simulations. The numerical predictions of electron temperature (2D simulations) and electron density (3D simulations) were found to be in close agreement to those estimated through experiments.

Bashir, M.; Rees, Julia M.; Bashir, S.; Zimmerman, William B.

2014-06-01

329

The Argon Dark Matter Experiment  

E-print Network

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.

Christian Regenfus

2009-12-15

330

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

331

ORIGINAL PAPER Coagulation temperature affects the microstructure  

E-print Network

at 36 °C. At a higher coagulation temperature (36 °C), the size of the casein micelle aggregates hydrophobic and ionic interactions and the rearrangement of casein micelles. This characteristic and the direct effect of coagulation temperature on physical properties of the fat and the casein micelles. Our

Paris-Sud XI, Université de

332

Blood coagulation in patients with toxic goiter  

Microsoft Academic Search

Data are presented on the study of blood coagulation in 128 patients ; with toxic goiter--- mild, moderately severe, and severe forms before and after ; mercazolyl (mild) and ¹³¹I (moderately severe and severe) treatment. Signs ; of reduction of blood coagulative activity and an increase of fibrinolytic ; activity, and heparin, which elevated in parallel with the clinical severity

V. M. Panchenko; A. V. Antonidze

1973-01-01

333

Coagulation-crossflow microfiltration of domestic wastewater  

Microsoft Academic Search

The effect of using alum, polyaluminum silicate sulfate (PASS), and lime as coagulants on the performance of crossflow microfiltration of domestic wastewater was investigated. The primary membrane used throughout the study was made of woven polyester, while the dynamic membrane was formed by circulating MnO2 precipitate. Slug doses of the coagulants were added to the circulation tank of the experimental

Muhammad H. Al-Malack; G. K. Anderson

1996-01-01

334

Textile wastewater purification through natural coagulants  

NASA Astrophysics Data System (ADS)

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.

Beltrán-Heredia, J.; Sánchez-Martín, J.; Rodríguez-Sánchez, M. T.

2011-09-01

335

Coagulation and fibrinolysis in injured patients  

PubMed Central

Serial changes in coagulation and fibrinolysis studied among 42 patients admitted to hospital with a wide variety of injuries are reported. The first hours after trauma are dominated by an acceleration of fibrinolysis (clot lysis) and clotting time which are often followed by an abrupt rebound to prolonged fibrinolysis and normal clotting. Evidence is presented that acceleration of fibrinolysis is due to flooding of the circulation by plasminogen activator and that prolongation is probably due to an inhibitor. A prolonged prothrombin time, increased prothrombin consumption index, an acceleration of the heparin-retarded clotting time, and a fall in the platelet count are also frequent during the first hours after injury. There is evidence also of an early deficiency in factor V and the onset of a fall in factor VII and prothrombin. The following days are characterized by continued prolongation of fibrinolysis, a lengthening of clotting time, and an increased prothrombin consumption index suggestive of a defect in thrombo-plastin generation. Subsequent periods of prolonged fibrinolysis may develop. Prothrombin time often continues prolonged for one to three weeks and may vary phasically; plasma prothrombin and factor VII are reduced but there is now little change in factor V. The platelet count continues to fall for one to three days, then a thrombocytosis develops, often with abnormally high platelet levels, a week or so later. Plasma fibrinogen rises within 24 hours to reach a plateau maximum a few days later and levels remain high for prolonged periods in the severely injured. Various changes are related to or influenced by the severity of trauma. Mechanisms are discussed, including thrombosis in vivo, and reference is made to homeostatic significance and its possible breakdown. PMID:14103515

Innes, D.; Sevitt, S.

1964-01-01

336

Surface plasmon resonance detection of blood coagulation and platelet adhesion under venous and arterial shear conditions  

Microsoft Academic Search

A surface plasmon resonance (SPR) based flow chamber device was designed for real time detection of blood coagulation and platelet adhesion in platelet rich plasma (PRP) and whole blood. The system allowed the detection of surface interactions throughout the 6mm length of the flow chamber. After deposition of thromboplastin onto a section of the sensor surface near the inlet of

Kenny M. Hansson; Knut Johansen; Jonas Wetterö; Goran Klenkar; Johan Benesch; Ingemar Lundström; Tomas L. Lindahl; Pentti Tengvall

2007-01-01

337

Apoptotic hepatocellular carcinoma HepG2 cells accelerate blood coagulation  

Microsoft Academic Search

Backgrounds and Aim: Intrasinusoidal microthrombosis is considered to be a cause of massive hepatocyte death in fulminant hepatic failure. Generally, apoptotic cells express phosphatidyl serine (PS) outside the plasma membrane, which is also expressed on the surface of activated platelets and accelerates fibrin–thrombus formation. Therefore, the acceleration of blood coagulation on the surface of apoptotic hepatocytes may occur because hepatocytes

Yasuhiro Miyamoto; Yasuhiro Takikawa; Shi De Lin; Shinichiro Sato; Kazuyuki Suzuki

2004-01-01

338

Comparison of a novel polytitanium chloride coagulant with polyaluminium chloride: coagulation performance and floc characteristics.  

PubMed

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

Zhao, Y X; Phuntsho, S; Gao, B Y; Yang, Y Z; Kim, J-H; Shon, H K

2015-01-01

339

Resection of meningiomas with implantable microwave coagulation  

SciTech Connect

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%.

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

340

Transfusion and coagulation management in liver transplantation  

PubMed Central

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

Clevenger, Ben; Mallett, Susan V

2014-01-01

341

Argon-40-argon-39 dating of Apollo sample 15555.  

NASA Technical Reports Server (NTRS)

An age of 3.33 (plus or minus 0.05) b.y. was obtained for Apollo 15 sample 15555 by argon-40-argon-39 dating. The age of rock 15555, a basalt from the rim of Hadley Rille, establishes an upper limit to the age of the rille. The basalt flows filling the Hadley Rille section of the Imbrium basin postdate the formation of the basin - as measured by the Apollo 14 samples of the Fra Mauro formation - by at least 500 m.y. Therefore, the mare basalts cannot be simple impact melts but rather must result from some igneous activity on the moon.

Alexander, E. C., Jr.; Davis, P. K.; Lewis, R. S.

1972-01-01

342

Acute Disseminated Intravascular Coagulation in Neuroendocrine Carcinoma  

PubMed Central

Malignancy is a common cause of disseminated intravascular coagulation and usually presents as a chronic disorder in solid organ tumours. We present a rare case of recurrent acute disseminated intravascular coagulation in neuroendocrine carcinoma after manipulation, firstly, by core biopsy and, later, by cytotoxic therapy causing a release of procoagulants and cytokines from lysed tumour cells. This is reminiscent of tumour lysis syndrome where massive quantities of intracellular electrolytes and nucleic acid are released, causing acute metabolic imbalance and renal failure. This case highlights the potential complication of acute disseminated intravascular coagulation after trauma to malignant cells. PMID:23139666

Teh, Ru-Wen; Tsoi, Daphne T.

2012-01-01

343

The singular coagulation equation with multiple fragmentation  

NASA Astrophysics Data System (ADS)

In this paper, we prove the global existence and uniqueness of the solutions to the initial-value problem for the coagulation-fragmentation equation with singular coagulation kernel and multiple fragmentation kernel. The solution obtained in this case also satisfies the mass conservation law. The proof is based on strong convergence methods applied to suitably chosen unbounded coagulation kernels having singularities in both the coordinate axes and satisfying certain growth conditions, which can possibly reach up to a quadratic growth at infinity, and the fragmentation kernel covers a very large class of unbounded functions.

Saha, Jitraj; Kumar, Jitendra

2014-08-01

344

Temperature Distribution in a Pilot Plasma Tundish: Comparison Between Plasma Torch and Graphite Electrode Systems  

Microsoft Academic Search

Arc, bath, and refractory wall temperatures are measured in a pilot transferred-arc plasma furnace by atomic emission spectroscopy (AES) and multiwavelength pyrometry. Argon plasma torch and graphite electrode with nitrogen as plasma gas are both examined and compared using the steel bath as anode. With argon, a two-slope characteristic curve is measured for arc temperature, which ranges from 9000 to

J. M. Badie; Ph. Bertrand; G. Flamant

2001-01-01

345

A simple, general approach of allosteric coagulation enzyme inhibition through monosulfated hydrophobic scaffolds.  

PubMed

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

Sidhu, Preetpal Singh; Zhou, Qibing; Desai, Umesh R

2014-12-15

346

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

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

Boyer, Edmond

347

Calculation of the shifts of argon spectral lines  

NASA Astrophysics Data System (ADS)

Shifts due to collisions with charged particles (Stark broadening ) and neutral atoms, were determined for nine argon spectral lines corresponding to the transitions 3p5nd-3p54p for n = 4-7, 3p56s-3p54d and 3p54p' -3p54s in order to estimate their usability for the research and diagnostics of a plasma in a surface-wave discharge at atmospheric pressure.

Christova, M.; Christov, L.; Dimitrijevi?, M. S.; Andreev, N.

2008-10-01

348

Electron densities and energies of a guided argon streamer in argon and air environments  

NASA Astrophysics Data System (ADS)

In this study we report the temporally and spatially resolved electron densities and mean energies of a guided argon streamer in ambient argon and air obtained by Thomson laser scattering. The plasma is driven by a positive monopolar 3.5 kV pulse, with a pulse width of 500 ns and a frequency of 5 kHz which is synchronized with the high repetition rate laser system. This configuration enables us to use the spatial and temporal stability of the guided streamer to accumulate a multitude of laser/plasma shots by a triple grating spectrometer equipped with an ICCD camera and to determine the electron parameters. We found a strong initial ne-overshoot with a maximum of 7 × 1019 m-3 and a mean electron energy of 4.5 eV. This maximum is followed by a fast decay toward the streamer channel. Moreover, a 2D distribution of the electron density is obtained which exhibits a peculiar mushroom-like shape of the streamer head with a diameter significantly larger than that of the emission profile. A correlation of the width of the streamer head with the expected pre-ionization channel is found.

Hübner, S.; Hofmann, S.; van Veldhuizen, E. M.; Bruggeman, P. J.

2013-12-01

349

Hyperlipidemia, tissue factor, coagulation, and simvastatin.  

PubMed

Hyperlipidemia affects millions of people worldwide and is a major risk factor for cardiovascular disease. People with hyperlipidemia have elevated levels of serum cholesterol and an increased risk of thrombosis. Studies have suggested that oxidized lipoproteins, such as oxidized low-density lipoprotein (oxLDL), contribute to the development of a pro-thrombotic state. In this review, we discuss our recent studies demonstrating a role for hematopoietic cell-derived tissue factor (TF) expression in the activation of coagulation and increased thrombosis associated with hyperlipidemia. In addition, we investigated the effect of simvastatin on TF expression and coagulation. We found that simvastatin reduced leukocyte TF expression, TF? microparticles, and coagulation. These results and earlier studies suggest that the anti-coagulant activity of statins is due, in part, to their ability to reduce monocyte TF expression in patients with cardiovascular disease. PMID:24016468

Owens, Albert Phillip; Byrnes, James Robert; Mackman, Nigel

2014-04-01

350

21 CFR 864.5400 - Coagulation instrument.  

Code of Federal Regulations, 2010 CFR

... 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)...

2010-04-01

351

21 CFR 864.5400 - Coagulation instrument.  

Code of Federal Regulations, 2011 CFR

... 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)...

2011-04-01

352

21 CFR 864.5400 - Coagulation instrument.  

Code of Federal Regulations, 2014 CFR

... 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)...

2014-04-01

353

21 CFR 864.5400 - Coagulation instrument.  

Code of Federal Regulations, 2013 CFR

... 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)...

2013-04-01

354

21 CFR 864.5400 - Coagulation instrument.  

Code of Federal Regulations, 2012 CFR

... 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)...

2012-04-01

355

Coagulation testing in the perioperative period  

PubMed Central

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.

Thiruvenkatarajan, Venkatesan; Pruett, Ashlee; Adhikary, Sanjib Das

2014-01-01

356

Thermochemical nonequilibrium modeling of a low-power argon arcjet wind tunnel  

NASA Astrophysics Data System (ADS)

Non-transferred low-power arcjet wind tunnels with pure argon working gas are widely used as inexpensive laboratory plasma sources to simulate a weakly ionized supersonic flow around an atmospheric entry vehicle. Many experiments using argon arcjet wind tunnels have been conducted, but their numerical modeling is not yet complete. We develop an axisymmetric Navier-Stokes model with thermochemical nonequilibrium and arc discharge that simulates the entire flow field in a steady-operating argon arcjet wind tunnel, which consists of the inside of the arcjet and its arc plume entering a rarefied vacuum chamber. The computational method we develop makes it possible to reproduce the arc column behavior far from thermochemical equilibrium in the low-voltage discharge mode typical of argon arcjets. Furthermore, the results reveal that the plasma characteristic of being far from thermal equilibrium, which is particular to argon, causes the arcjet to operate in the low-voltage mode and its arc plume to be completely thermochemically frozen. Moreover, the arc plume has electroconductive non-uniformity with an electrically insulating boundary in the radial direction. Our computed values for the shock standoff distance in front of a blunt body and the drag exerted on it agree with measured values. As a result, the self-consistent computational model in this study is useful in investigating thermochemical nonequilibrium plasma flows in argon arcjet wind tunnels.

Katsurayama, Hiroshi; Abe, Takashi

2013-02-01

357

Dust Coagulation in Protoplanetary Accretion Disks  

NASA Technical Reports Server (NTRS)

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.

Schmitt, W.; Henning, Th.; Mucha, R.

1996-01-01

358

Extracellular protein disulfide isomerase regulates coagulation on endothelial cells through modulation of phosphatidylserine exposure  

PubMed Central

Tissue factor (TF) is the cellular receptor for plasma protease factor VIIa (FVIIa), and the TF-FVIIa complex initiates coagulation in both hemostasis and thrombosis. Cell surface-exposed TF is mainly cryptic and requires activation to fully exhibit the procoagulant potential. Recently, the protein disulfide isomerase (PDI) has been hypothesized to regulate TF decryption through the redox switch of an exposed disulfide in TF extracellular domain. In this study, we analyzed PDI contribution to coagulation using an in vitro endothelial cell model. In this model, extracellular PDI is detected by imaging and flow cytometry. Inhibition of cell surface PDI induces a marked increase in TF procoagulant function, whereas exogenous addition of PDI inhibits TF decryption. The coagulant effects of PDI inhibition were sensitive to annexin V treatment, suggesting exposure of phosphatidylserine (PS), which was confirmed by prothrombinase assays and direct labeling. In contrast, exogenous PDI addition enhanced PS internalization. Analysis of fluorescent PS revealed that PDI affects both the apparent flippase and floppase activities on endothelial cells. In conclusion, we identified a new mechanism for PDI contribution to coagulation on endothelial cells, namely, the regulation of PS exposure, where PDI acts as a negative regulator of coagulation. PMID:20448108

Popescu, Narcis I.; Lupu, Cristina

2010-01-01

359

Ovarian cancer, the coagulation pathway, and inflammation  

PubMed Central

Epithelial ovarian cancer (EOC) represents the most frequent cause of death in the United States from a cancer involving the female genital tract. Contributing to the overall poor outcome in EOC patients, are the metastases to the peritoneum and stroma that are common in this cancer. In one study, cDNA microarray analysis was performed on fresh tissue to profile gene expression in patients with EOC. This study showed a number of genes with significantly altered expression in the pelvic peritoneum and stroma, and in the vicinity of EOC implants. These genes included those encoding coagulation factors and regulatory proteins in the coagulation cascade and genes encoding proteins associated with inflammatory responses. In addition to promoting the formation of blood clots, coagulation factors exhibit many other biologic functions as well as tumorigenic functions, the later including tumor cell proliferation, angiogenesis, invasion, and metastasis. Coagulation pathway proteins involved in tumorigenesis consist of factor II (thrombin), thrombin receptor (protease-activated receptors), factor III (tissue factor), factor VII, factor X and factor I (fibrinogen), and fibrin and factor XIII. In a recent study we conducted, we found that factor XII, factor XI, and several coagulation regulatory proteins, including heparin cofactor-II and epithelial protein C receptor (EPCR), were also upregulated in the peritoneum of EOC. In this review, we summarize evidence in support of a role for these factors in promoting tumor cell progression and the formation of ascites. We also discuss the different roles of coagulation factor pathways in the tumor and peritumoral microenvironments as they relate to angiogenesis, proliferation, invasion, and metastasis. . Since inflammatory responses are another characteristic of the peritoneum in EOC, we also discuss the linkage between the coagulation cascade and the cytokines/chemokines involved in inflammation. Interleukin-8, which is considered an important chemokine associated with tumor progression, appears to be a linkage point for coagulation and inflammation in malignancy. Lastly, we review findings regarding the inflammatory process yielded by certain clinical trials of agents that target members of the coagulation cascade in the treatment of cancer. Current data suggest that disrupting certain elements of the coagulation and inflammation processes in the tumor microenvironment could be a new biologic approach to cancer therapeutics. PMID:15969748

Wang, Xipeng; Wang, Ena; Kavanagh, John J; Freedman, Ralph S

2005-01-01

360

Helical Organization of Blood Coagulation Factor VIII on Lipid Nanotubes  

PubMed Central

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

Miller, Jaimy; Dalm, Daniela; Koyfman, Alexey Y.; Grushin, Kirill; Stoilova-McPhie, Svetla

2014-01-01

361

Collaborative study for the establishment of replacement batches for human coagulation factor IX concentrate reference standards.  

PubMed

The European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) batch 1, the World Health Organisation (WHO) 3rd International Standard, Human (IS, 96/854) and the FDA Standard for human blood coagulation Factor IX concentrate have been available since 1996, following their establishment by a common collaborative study. Due to dwindling stocks of all three standards, a new WHO-EDQM-FDA tri-partite collaborative study was launched to establish replacement batches. Thirty laboratories from fourteen countries took part in the collaborative study to assign potency values to candidate preparations. Three candidates, one of recombinant and two of human plasma-derived origins, were assayed against the 3rd IS for Blood Coagulation Factor IX, Concentrate, Human (96/854). The 3rd IS for Blood Coagulation Factors II, VII, IX and X, Plasma, Human (99/826) was also included to evaluate the relationship between the factor IX plasma and concentrate unitage. Thirty-two sets of clotting assay results and two sets of chromogenic assay data were analysed. There was a significant difference in potency estimates by these two methods for the recombinant candidate (sample B) and the plasma IS (sample P). Similar potency values were obtained for the plasma derived products (monoclonal antibody- and chromatography-purified factor IX, samples C and D) by clotting and chromogenic assays. For the clotting assays, intra-laboratory variability (GCV) was found to range from 0.5 - 21.7%, with the GCV for the majority of laboratories being less than 10%. Good inter-laboratory agreement, with the majority of the GCV being less than 10% (GCV range = 4.7 - 10.6 %) was also obtained. The mean potency values estimated by the clotting assay using plasma as pre-diluent (as directed by the Ph. Eur. general chapter method) did not differ from values obtained using buffer. Taking into account the preliminary stability data, the intra- and inter-laboratory variability, and the differences between the clotting and chromogenic assay results, sample C (07/182) was established as the Human coagulation factor IX concentrate BRP batch 2, with a potency value of 7.9 IU/ampoule assigned with clotting assay results. As an outcome of this tri-partite collaborative study, the same sample C (07/182) has also been adopted as the 4th International Standard for Blood Coagulation Factor IX, Concentrate, Human by the Expert Committee on Biological Standardisation (ECBS) of the World Health Organisation (WHO), and as the replacement batch for the reference standard for Human coagulation factor IX concentrate by the FDA. PMID:19220978

Gray, E; Pickering, W; Hockley, J; Rigsby, P; Weinstein, M; Terao, E; Buchheit, K-H

2008-12-01

362

Effect of Crocus sativus L. (saffron) on coagulation and anticoagulation systems in healthy volunteers.  

PubMed

Saffron showed some effects on blood coagulation and platelet aggregation in in vitro and in vivo studies. In a clinical trial with a limited number volunteers, saffron tablets influenced on bleeding time. In this study, the effect of saffron on plasma level of fibrinogen, factor VII (as coagulant agent), C and S protein (as anti-coagulant agent), PT and PTT in a larger sample size was evaluated. The study was a double-blind, placebo-controlled study consisting of 1?week treatment with 200?mg and 400?mg saffron tablets. Sixty healthy volunteers (age range 20-50?years) were selected for the study. The volunteers were divided into three groups of 20 each. Group 1 received placebo; Groups 2 and 3 received 200?mg and 400?mg saffron tablets, respectively, for 7?days (1 tablet per day). Before and after 7?days treatment and also 1?month after that, blood samples were taken. The plasma levels of fibrinogen, factor VII, C and S protein, PT and PTT were evaluated. Statistical analysis showed no difference between groups for any of evaluated factors. This study rejected any effect of saffron with dose of 200 and 400?mg for 1?week on coagulant and anticoagulant system. PMID:23733488

Ayatollahi, Hossein; Javan, Atefeh Ordoei; Khajedaluee, Mohammad; Shahroodian, Masood; Hosseinzadeh, Hossein

2014-04-01

363

Elastic scattering spectroscopy of coagulated brain tissues  

NASA Astrophysics Data System (ADS)

The goal of this study was to differentiate the parts of lamb brain according to elastic scattering spectroscopy and detect the optical alterations due to coagulation. Cells and tissues are not uniform and have complex structures and shapes. They can be referred to as scattering particles. The process of scattering depends on the light wavelength and on the scattering medium properties; especially on the size and the density of the medium. When elastic scattering spectroscopy (ESS) is employed, the morphological alterations of tissues can be detected using spectral measurements of the elastic scattered light over a wide range of wavelengths. In this study firstly, the slopes of ESS spectra were used to differentiate the parts of lamb brains (brainstem, cerebellum, gray matter, white matter) in vitro in the range of 450 - 750 nm. Secondly, tissues were coagulated at different temperatures (45, 60, and 80 °C) and ESS spectra were taken from native and coagulated tissues. It was observed that as the coagulation temperature increased, the slope of the elastic scattering spectra decreased. Thus, optical properties of tissues were changed with respect to the change in nuclear to cytoplasmic ratio due to the water loss. Results showed that the slopes of ESS spectra in the visible range revealed valuable information about the morphological changes caused by coagulation.

Ate?, Filiz; Tabako?lu, Ha?im Özgür; Bozkulak, Özgüncem; Canpolat, Murat; Gülsoy, Murat

2006-02-01

364

Magnetic particle imaging of blood coagulation  

NASA Astrophysics Data System (ADS)

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.

Murase, Kenya; Song, Ruixiao; Hiratsuka, Samu

2014-06-01

365

Magnetic particle imaging of blood coagulation  

SciTech Connect

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.

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

366

Spectral diagnosis of plasma jet at atmospheric pressure  

Microsoft Academic Search

A new approach to surface modification of materials using dielectric barrier discharge (DBD) plasma jet at atmospheric pressure is presented in this paper. The emission spectral lines of argon plasma jet at atmospheric pressure were recorded by the grating spectrograph HR2000 and computer software. The argon plasma emission spectra, whose range is from 300nm to 1000nm, were measured at different

X. L. Tang; G. Qiu; C. Li; X. P. Wang; X. P. Feng

2009-01-01

367

Boltzmann expansion in a radiofrequency conical helicon thruster operating in xenon and argon  

SciTech Connect

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.

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

368

Discharge characteristics of atmospheric-pressure radio-frequency glow discharges with argon/nitrogen  

SciTech Connect

In this letter, atmospheric-pressure glow discharges in {gamma} mode with argon/nitrogen as the plasma-forming gas using water-cooled, bare copper electrodes driven by radio-frequency power supply at 13.56 MHz are achieved. The preliminary studies on the discharge characteristics show that, induced by the {alpha}-{gamma} coexisting mode or {gamma} mode discharge of argon, argon-nitrogen mixture with any mixing ratios, even pure nitrogen, can be employed to generate the stable {gamma} mode radio-frequency, atmospheric-pressure glow discharges and the discharge voltage rises with increasing the fraction of nitrogen in the argon-nitrogen mixture for a constant total gas flow rate.

Wang Huabo; Sun Wenting; Li Heping; Bao Chengyu; Gao Xing; Luo Huiying [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); School of Public Health and Family Medicine, Capital University of Medical Sciences, Beijing 100069 (China); Beijing Center for Diseases Control and Prevention, Beijing 100013 (China)

2006-10-16

369

Fibrinolysis and the control of blood coagulation  

PubMed Central

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

Chapin, John C.; Hajjar, Katherine A.

2014-01-01

370

Fibrinolysis and the control of blood coagulation.  

PubMed

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

Chapin, John C; Hajjar, Katherine A

2015-01-01

371

Endoscopic Coagulation of Choroid Plexus in Hydranencephaly  

PubMed Central

Hydranencephaly is a rare congenital disease defined as an absence of cerebral hemispheres with an intact thalamus, brain stem, and cerebellum. Generally, patients with hydranencephaly require cerebro-spinal fluid diversion due to progressive hydrocephalus. An excellent view of the choroid plexus and advancement of the neurosurgical endoscope were possible, leading to easy coagulation of the choroid plexus to balance cerebro-spinal fluid production without the use of a shunt device. We present this rare case and good treatment outcome from endoscopic coagulation of the choroid plexus. PMID:25237437

Kim, Sang Young; Cho, Jae Hoon

2014-01-01

372

A DSMC Study of Low Pressure Argon Discharge  

NASA Technical Reports Server (NTRS)

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.

Hash, David B.; Meyyappan, Meyya; Arnold, James O. (Technical Monitor)

1997-01-01

373

Computer-assisted interstitial laser coagulation for BPH  

NASA Astrophysics Data System (ADS)

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.

Ho, Gideon; Barrett, Adrian R. W.; Ng, Wan S.; Lim, Liam G.; Cheng, Wai S.

2001-06-01

374

ORIGINAL PAPER Variations in coagulation properties of cheese milk  

E-print Network

ORIGINAL PAPER Variations in coagulation properties of cheese milk from three Danish dairy breeds a study on the variation of coagulation properties in individual cow's milk measured by a novel free of poorly and even non-coagulating (NC) milk in Denmark, and based on that, the paper reports

Boyer, Edmond

375

Platelet-Induced Thrombin Generation Time: A New Sensitive Global Assay for Platelet Function and Coagulation  

Microsoft Academic Search

A new sensitive test – platelet-induced thrombin generation time (PITT) – is described, in which the formation of thrombin in partially anticoagulated platelet-rich plasma (PRP) leads to aggregation immediately followed by coagulation of PRP. 0.6 ml PRP are rotated in a disk-shaped cuvette within the light beam of a photometer. In PITT, platelets stick to the cuvette wall and, mediated

C. Roman; U. Herpel; E. Kling; B. Scholz; H. K. Breddin

1992-01-01

376

Original article Chemical composition and coagulation properties  

E-print Network

composition was the same in both breeds. The pH of the Mo milk was lower (­0.07), coagulation time and curd' milk Vincenzo CHIOFALOa, Roberta MALDONATOa, Bruno MARTINb*, Didier DUPONTc, Jean-Baptiste COULONb October 2000) Abstract -- The chemical composition and clotting properties of milk from 45 Modicana (Mo

Paris-Sud XI, Université de

377

[Intravascular coagulation associated with aortic aneurysm].  

PubMed

A consumption coagulopathy is presented, featuring a chronic and localized intravascular coagulation syndrome, with cutaneous manifestations exclusively, associated to an aortic aneurysm. The infrequency of this association is remarkable, being assumed as capital factors from the physiopathogenic side the parietal alteration and the blood stasis. They both determine the consumption of platelets adding further thromboplastic material that maintains the process. PMID:2695719

Macedo, N A; Turak, V; Bravo, D; González, V

1989-01-01

378

Liquid Argon Calorimetry for ATLAS  

NASA Astrophysics Data System (ADS)

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.

Robinson, Alan

2008-05-01

379

Could light meal jeopardize laboratory coagulation tests?  

PubMed Central

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

Lima-Oliveira, Gabriel; Salvagno, Gian Luca; Lippi, Giuseppe; Danese, Elisa; Gelati, Matteo; Montagnana, Martina; Picheth, Geraldo; Guidi, Gian Cesare

2014-01-01

380

Dusty plasmas  

SciTech Connect

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.

Jones, M.E.; Winske, D.; Keinigs, R.; Lemons, D.

1996-05-01

381

Coagulation and metastasis: what does the experimental literature tell us?  

PubMed

Inhibition of coagulation greatly limits cancer metastasis in many experimental models. Cancer cells trigger coagulation, through expression of tissue factor or P-selectin ligands that have correlated with worse prognosis in human clinical studies. Cancer cells also affect coagulation through expression of thrombin and release of microparticles that augment coagulation. In the cancer-bearing host, coagulation facilitates tumour progression through release of platelet granule contents, inhibition of Natural Killer cells and recruitment of macrophages. We are revisiting this literature in the light of recent studies in which treatment of clinical cohorts with anticoagulant drugs led to diminished metastasis. PMID:23691951

Gil-Bernabé, Ana M; Lucotti, Serena; Muschel, Ruth J

2013-08-01

382

Blood Coagulation Dynamics in Hemostasis  

PubMed Central

Our studies involve computational simulations, a reconstructed plasma/platelet proteome, whole blood in vitro and blood exuding from microvascular wounds. All studies indicate that in normal hemostasis, the binding of tissue factor (Tf) with plasma factor (f) VIIa (extrinsic fXase complex) results in the INITIATION PHASE of the procoagulant response. This phase is negatively regulated by tissue factor pathway inhibitor (TFPI) in combination with antithrombin (AT) and the protein C (PC) pathway. The synergy between these inhibitors provides a threshold-limited reaction in which a stimulus of sufficient magnitude must be provided for continuation of the reaction. With sufficient stimulus, the fXa produced activates some prothrombin. This initial thrombin activates the procofactors and platelets required for presentation of the intrinsic fXase (fVIIIa-fIXa) and prothrombinase (fVa-fXa) complexes which drive the subsequent PROPAGATION PHASE; continuous downregulation of which is provided by AT and the thrombin-thrombomodulin-PC complex. FXa generation during the PROPAGATION PHASE is largely (>90%) provided by the intrinsic fXase complex. Tf is required for the INITIATION PHASE of the reaction but becomes non-essential once the PROPAGATION PHASE has been achieved. The PROPAGATION PHASE catalysts (fVIIIa-fIXa and fVa-fXa) continue to drive the reaction as blood is resupplied to the wound site by flow. Ultimately, the control of the reaction is governed by the pro- and anticoagulant dynamics and the supply of blood reactants to the site of a perforating injury. Our systems have been utilized to examine the qualities of hypothetical and novel antihemorrhagic and anticoagulation agents in epidemiologic studies of venous and arterial thrombosis and the hemorrhagic pathology. PMID:19151839

Mann, Kenneth G.; Orfeo, Thomas; Butenas, Saulius; Undas, Anetta; Brummel-Ziedins, Kathleen

2011-01-01

383

Model of a stationary microwave argon discharge at atmospheric pressure  

SciTech Connect

The many applications of microwave gas discharges at atmospheric pressure in various fields of science, technology and medicine require an adequate model of these discharges. Such a model is based on the electromagnetic wave's propagation properties and on the elementary processes in the discharge bulk. In contrast to the microwave discharges at low-gas pressures, where many elementary processes might be ignored because of their negligible contribution to the electron and heavy particle's balance equations, for such discharges at atmospheric pressure the consideration of a large number of collisional processes is mandatory. For the build of a successful discharge-column model one needs three important quantities, notably the power {theta} necessary for sustaining an electron - ion pair, electron - neutral collision frequency for momentum transfer v{sub en}, and gas temperature T{sub g}. The first two key parameters are obtained by a collisional-radiative model of the argon at atmospheric pressure, while the microwave frequency {omega}/2{pi} = 2.45 GHz, plasma column radius R, gas pressure p and gas temperature T{sub g} are fixed external parameters determined by the experimental conditions. Here, we present a model of a capillary argon microwave plasma column with a length L {approx_equal} 14 cm, sustained by wave power of 110 W - the model yields the longitudinal distributions of the plasma density, expended wave power, wave electric field magnitude, and complex wave number.

Zhelyazkov, I. [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria); Pencheva, M.; Benova, E. [Department for Language Teaching and International Students, Sofia University, BG-1111 Sofia (Bulgaria)

2008-03-19

384

Safety Data Sheet Material Name: ARGON, COMPRESSED SDS ID: 00232349  

E-print Network

Safety Data Sheet Material Name: ARGON, COMPRESSED SDS ID: 00232349, coma Long Term: no information is available #12;Safety Data Sheet Material Name: ARGON, COMPRESSED SDS;Safety Data Sheet Material Name: ARGON, COMPRESSED SDS ID: 00232349 ___________________________________________________

Carpick, Robert W.

385

21 CFR 868.1075 - Argon gas analyzer.  

Code of Federal Regulations, 2012 CFR

... 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...

2012-04-01

386

21 CFR 868.1075 - Argon gas analyzer.  

Code of Federal Regulations, 2013 CFR

... 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...

2013-04-01

387

21 CFR 868.1075 - Argon gas analyzer.  

Code of Federal Regulations, 2014 CFR

... 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...

2014-04-01

388

CERN, 23 October 2001 A prototype magnetized liquid Argon detector  

E-print Network

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

McDonald, Kirk

389

21 CFR 868.1075 - Argon gas analyzer.  

Code of Federal Regulations, 2011 CFR

... 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...

2011-04-01

390

21 CFR 868.1075 - Argon gas analyzer.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 2010-04-01 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...

2010-04-01

391

Plasma Processing of Metallic and Semiconductor Thin Films in the Fisk Plasma Source  

NASA Technical Reports Server (NTRS)

The use of plasmas to process materials has become widespread throughout the semiconductor industry. Plasmas are used to modify the morphology and chemistry of surfaces. We report on initial plasma processing experiments using the Fisk Plasma Source. Metallic and semiconductor thin films deposited on a silicon substrate have been exposed to argon plasmas. Results of microscopy and chemical analyses of processed materials are presented.

Lampkin, Gregory; Thomas, Edward, Jr.; Watson, Michael; Wallace, Kent; Chen, Henry; Burger, Arnold

1998-01-01

392

Dissociative recombination in ultraviolet filamentary plasma gratings.  

PubMed

We investigated collisions of nitrogen and argon gas mixture with energetic electrons accelerated by Bragg incident intense infrared femtosecond laser pulses in ultraviolet filamentary plasma gratings. Significant decrease of fluorescence spectra of argon atoms were observed when a small amount of nitrogen gas was mixed with argon gas that facilitated observable argon-nitrogen collisions. We experimentally measured the fluorescence emission from the argon and nitrogen gas mixture under different driving pulse energies, the fluorescence decay dynamics after the impact excitation, as well as the fluorescence intensity dependence on the nitrogen and argon pressures. The experimental measurements were based on the electron acceleration and its subsequent impact with the gas mixture in the filamentary plasma gratings, which was essential for the observation of the dominant dissociative recombination in the gas mixture. PMID:24921794

Zhou, Hui; Li, Wenxue; Wang, Di; Shi, Liping; Ding, Liang'en; Zeng, Heping

2014-05-01

393

The effects of argon pressurization on melt rate and arc distribution during vacuum arc remelting of Alloy 718  

SciTech Connect

The effects of argon addition to the vacuum arc remelting (VAR) process were studied in both laboratory and industrial experiments while remelting Alloy 718. The results demonstrate that argon can be added to an industrial VAR furnace to relatively high partial pressures without decreasing the melt rate, drip-short frequency, or constricting the arc plasma to a local region of the electrode surface. Laboratory experiments illustrate that this result is dependent on electrode chemistry, possibly related to magnesium content.

Williamson, R.L.; Zanner, F.J. (Sandia National Labs., Albuquerque, NM (United States)); Harrison, R. (Cameron Iron Works, Inc., Houston, TX (United States)); Thompson, R. (Teledyne Allvac, Monroe, NC (United States))

1992-01-01

394

The effects of argon pressurization on melt rate and arc distribution during vacuum arc remelting of Alloy 718  

SciTech Connect

The effects of argon addition to the vacuum arc remelting (VAR) process were studied in both laboratory and industrial experiments while remelting Alloy 718. The results demonstrate that argon can be added to an industrial VAR furnace to relatively high partial pressures without decreasing the melt rate, drip-short frequency, or constricting the arc plasma to a local region of the electrode surface. Laboratory experiments illustrate that this result is dependent on electrode chemistry, possibly related to magnesium content.

Williamson, R.L.; Zanner, F.J. [Sandia National Labs., Albuquerque, NM (United States); Harrison, R. [Cameron Iron Works, Inc., Houston, TX (United States); Thompson, R. [Teledyne Allvac, Monroe, NC (United States)

1992-03-01

395

Liquid argon calorimetry for the SSC  

SciTech Connect

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.

Gordon, H.A.

1990-01-01

396

Fast and interrupted expansion in cyclic void growth in dusty plasma  

NASA Astrophysics Data System (ADS)

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.

van de Wetering, F. M. J. H.; Brooimans, R. J. C.; Nijdam, S.; Beckers, J.; Kroesen, G. M. W.

2015-01-01

397

Determination of the rate coefficients of the electron-impact excitation from the metastable states to 2p states of argon by the emission line ratios in an afterglow plasma  

NASA Astrophysics Data System (ADS)

The rate coefficients of electron-impact excitation from the argon metastable to 2p states are measured in the afterglow of an rf pulsed capacitive discharge. In the afterglow, the 2p state densities are measured by optical emission spectroscopy, the time-resolved 1s state densities are measured by laser absorption, the time-resolved electron temperature (Te) and electron density are measured by a Langmuir probe. By employing these measured parameters, the electron-impact excitation rate coefficients are obtained from the rate balance equations of 2p states in the Te range from 0.7 to 1.2 eV. The measured rate coefficients are in good agreement with those obtained from the cross sections measured by Boffard et al. In addition, we obtain rate coefficients of the transitions from the metastable states to 2p1,7,10, whose measured values have not been reported before. These rate coefficients are also compared with the calculated ones (Zatsarinny et al with the R-matrix method, Srivastava et al with the Distorted wave method).

Cheng, Zhi-Wen; Zhu, Xi-Ming; Liu, Fei-Xiang; Pu, Yi-Kang

2014-07-01

398

Hydrofluorocarbon ion density of argon- or krypton-diluted CH2F2 plasmas: generation of CH2F+ and CHF2+ by dissociative-ionization in charge exchange collisions  

NASA Astrophysics Data System (ADS)

Ion densities of CH2F+ and CHF2+ were determined by dissociative ionization pathways in channels of charge exchange collisions, i.e. CH2F2 + M+ ? CH2F+ + F + M* and CHF2+ + H +M* [M = Ar, Kr] in CH2F2 plasmas diluted by a rare gas [M]. These channels simultaneously generated counter fragments of charge-neutral H and F atoms of interest for plasma etching processes. In Ar-diluted plasmas, CH2F+ ions predominated due to dissociative ionization between Ar+ [ca. 15.8?eV] and C–F appearance [dissociative ionization] energy [ca. 16?eV] to form CH2F+. In contrast, for Kr-diluted plasmas, C–H appearance energy [ca. 13.8?eV] predominated to produce a larger amount of CHF2+ ions due to a similar channel for charge exchange collisions between Kr+ [ca. 14?eV] and CH2F2. Thus, adding the ratio of Ar and Kr gas to CH2F2 plasmas provided control over the fraction of CH2F+ and CHF2+ ion densities.

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

2015-02-01

399

The coagulation characteristics of humic acid by using acid-soluble chitosan, water-soluble chitosan, and chitosan coagulant mixtures.  

PubMed

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

Chen, Chih-Yu; Wu, Chung-Yu; Chung, Ying-Chien

2014-11-27

400

Imaging of hydrogen halides photochemistry on argon and ice nanoparticles.  

PubMed

The photodissociation dynamics of HX (X = Cl, Br) molecules deposited on large ArN and (H2O)N, N? ? 10(2)-10(3), 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. PMID:25149788

Poterya, V; Lengyel, J; Pysanenko, A; Svr?ková, P; Fárník, M

2014-08-21

401

Dysregulation of coagulation in cerebral malaria  

PubMed Central

Cerebral malaria (CM) is a life-threatening complication of Plasmodium falciparum infection and represents a major cause of morbidity and mortality worldwide. The nature of the pathogenetic processes leading to the cerebral complications remains poorly understood. It has recently emerged that in addition to their conventional role in the regulation of haemostasis, coagulation factors have an inflammatory role that is pivotal in the pathogenesis of a number of acute and chronic conditions, including CM. This new insight offers important therapeutic potential. This review explores the clinical, histological and molecular evidence for the dysregulation of the coagulation system in CM, looking at possible underlying mechanisms. We discuss areas for future research to improve understanding of CM pathogenesis and for the development of new therapeutic approaches. PMID:19450727

Moxon, Christopher Alan; Heyderman, Robert Simon; Wassmer, Samuel Crocodile

2009-01-01

402

Electronic data management for the Hemochron Jr. Signature coagulation analyzer.  

PubMed

Point-of-care testing (POC, POCT) laboratory devices are being introduced into operating suites and critical care units in ever increasing numbers. The small, portable devices have gained in popularity because of their ease of use and the rapid availability of test results. POCT is an integral part of extracorporeal technology (ECT). A challenge associated with the growth of POC technology is related to management of the data generated by these devices. In the field of ECT, storing, retrieving, analyzing, viewing and charting quality control (QC) and patient test data generated with POC coagulation instruments is essential. We evaluated a premarket version of data management software developed for the Hemochron Jr. Signature coagulation analyzer, a PC-based software capable of fulfilling our objective. A database comprised of greater than 50 plasma and electronic QC results and greater than 140 patient sample results for ACT, PT, and aPTT tests was transferred from a Hemochron Jr. Signature device to two different PCs, each equipped with Hemochron ReportMaker software supplied by the manufacturer. Data files were transferred directly from the coagulation test unit to the PCs via an RS-232 cable. A variety of charts, reports, and file listings were created from the datasets using the software menus. Transfer of the complete database required less than 5 min. The relative speed and simplicity of the data interface promotes frequent charting of QC data, permitting real-time monitoring and early identification of data trends or values requiring intervention. If a subset of QC data is found to be incomplete, altered, or unacceptable, all patient samples tested during that period can be promptly identified. The software also includes data query tools useful for sorting and selecting specific subsets of patient and QC data. Electronic data management can facilitate compliance with quality control requirements and assist clinicians and laboratory personnel in the collection, storage, and review of quality control and patient test data. In addition, the patient and QC data are readily accessible when necessary for use in risk management assessment, accreditation, or litigation proceedings. PMID:12395963

Searles, Bruce; Nasrallah, Fadi; Graham, Susan; Tozer, Michelle

2002-09-01

403

Glial reactions to argon laser photocoagulation injury in rabbit and rat retinas  

NASA Astrophysics Data System (ADS)

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.

Humphrey, Martin F.; Chu, Yi; Sharp, Claudia; Moore, Stephen; Mann, Krishna; Rakoczy, Piroska; Constable, Ian J.

1996-04-01

404

Development of the selective coagulation process  

SciTech Connect

The selective hydrophobic coagulation (SHC) process is based on the recent finding that hydrophobic particles can be selectively coagulated without using traditional agglomerating agents or flocculants. The driving force for the coagulation is the attractive energy between hydrophobic surfaces, an interaction that has been overlooked in classical colloid chemistry. In most cases, selective separations can be achieved using simple pH control to disperse the mineral matter, followed by recovery of the coal coagula using techniques that take advantage of the size enlargement. In the present work, studies have been carried out to further investigate the fundamental mechanisms of the SHC process and the parameters that affect the process of separating coal from the ash-forming minerals and pyritic sulfur. Studies have included direct force measurements of the attractive interaction between model hydrophobic surfaces, in-situ measurements of the size distributions of coagula formed under a variety of operating conditions, and development of a population balance model to describe the coagulation process. An extended DLVO colloid stability model which includes a hydrophobic interaction energy term has also been developed to explain the findings obtained from the experimental studies. In addition to the fundamental studies, bench-scale process development test work has been performed to establish the best possible method of separating the coagula from dispersed mineral matter. Two types of separators, i.e., a sedimentation tank and a rotating drum screen, were examined in this study. The sedimentation tank proved to be the more efficient unit, achieving ash reductions as high as 60% in a single pass while recovering more than 90% of the combustible material. This device, which minimizes turbulence and coagula breakage, was used in subsequent test work to optimize design and operating parameters.

Yoon, R.H.; Luttrell, G.H.

1992-07-01

405

Patterned retinal coagulation with a scanning laser  

NASA Astrophysics Data System (ADS)

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.

Palanker, Daniel; Jain, ATul; Paulus, Yannis; Andersen, Dan; Blumenkranz, Mark S.

2007-02-01

406

Interference in Argon Auger Spectra  

SciTech Connect

Angle-dependent interference was observed in (e,2e) coincidence observations of argon L{sub 2,3}M{sub 2,3}M{sub 2,3} Auger transitions. The (e,2e) dynamics include an incident energy of 1.0keV, a fast electron scattering angle of 21{degree} for an energy range from 730 to 760eV with 2.5eV resolution and Auger electron detection angles of 60{degree} and 90{degree}. Observations were made below the Auger threshold and with excess energies of 22, 2, and 0.5eV. The interference, attributed to the interaction of Auger and satellite-state ionization processes, and the post-collision-interaction effects are quantified. {copyright} {ital 1997} {ital The American Physical Society}

Waterhouse, D.K.; Williams, J.F. [Centre for Atomic, Molecular and Surface Physics, Physics Department, The University of Western Australia, Nedlands, Perth, WA 6907 (Australia)] [Centre for Atomic, Molecular and Surface Physics, Physics Department, The University of Western Australia, Nedlands, Perth, WA 6907 (Australia)

1997-07-01

407

Shallow moonquakes - Argon release mechanism  

NASA Astrophysics Data System (ADS)

Apollo 17 surface mass-spectrometer observations have shown that 10 to the 27th to 10 to the 28th molecules of Ar-40 are released from the moon when shallow moonquakes occur. Model calculations, based on the seismic and strain energies released by the moonquakes, the volumes of their focal zones, and the surface areas of observed shallow thrust faults, indicate that 1.5 x 10 to the 25th to 2 x 10 to the 28th molecules of Ar-40 could be released by each shallow moonquake as a result of mylomization and possible frictional melting of the rocks within a few decimeters of the newly formed parts of the fault surface. The rapid escape of this Ar-40 along the fractures of the fault would produce the observed argon release event shortly after each moonquake.

Binder, A. B.

1980-11-01

408

[Coagulation and formation of malignant effusions].  

PubMed

Malignant effusions are a frequent problem for cancer patients. Due to the high resistance of tumor cells within these effusions, no effective treatment has been defined yet. Most patients exhibit additional phenomena related to hyper-coagulability such as elevated levels for d-dimers and prothrombin fragments f1.2; half of them suffer from manifest thrombosis or complications. We followed the hypothesis that the activated coagulation system contributes to the resistance of tumor cells and analyzed the effusions from cancer patients. The majority of isolated tumor cells aberrantly expressed PAR-1 thrombin receptors. In vitro pre-incubation of PAR-1 expressing human leukemia cells with thrombin resulted in a dose-dependent resistance to idarubicin. Within the effusions, we did not only find high concentrations of VEGF and tissue factor, but also all coagulation factors of the tissue factor pathway. Very high levels of prothrombin fragments f1.2 indicate constant thrombin generation. Upon the basis of these findings, we developed a multistep model elucidating the pathophysiological generation of malignant effusions, which might serve as a basis for further examinations. PMID:17938766

Gieseler, F; Stelck, B; Blume, L-F; Denker, M; Dohrmann, P; Mundhenke, C; Bauerschlag, D; Tiemann, M; Kunze, T

2007-09-01

409

Heparanase and coagulation-new insights.  

PubMed

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

Nadir, Yona

2014-10-01

410

Electrochemical coagulation for textile effluent decolorization.  

PubMed

The three most commonly used dyestuffs in textile industry are reactive, acid, and dispersed dyes. One dye from each group, C.I. Reactive Blue-19, C.I. Acid Red-266, and C.I. Disperse Yellow-218 was chosen to study the feasibility of coagulation for color removal. The dyes used in these experiments were chosen to represent the two major structural features: anthraquinone and azo dyes. Reactive Blue is an anthraquinone-based dye, and Acid Red and Disperse Yellow represent azo-based dyes. As there is no standard method to measure the color intensity, a Hach spectrophotometer was used to measure the absorbance before and after the dye solution was treated. Removal efficiencies on these dyes were obtained by measuring absorbance of a sample at 592 nm for Reactive Blue, 498 nm for Acid Red, and 428 nm for Disperse Yellow. Aluminum and ferric coagulants were produced in a parallel-plate electrochemical reactor by anodic dissolution. Removal efficiencies of more than 98%, in terms of absorbance, were observed in laboratory conditions. Removal was found highly dependent upon NaCl concentration, applied voltage, current density, and pH. The NaCl in the solution effectively reduced the power consumption and promoted the coagulant generation by depasivating the Al-water and Fe-water electrochemical systems. The processes were determined to be highly NaCl dependent. A mechanism was proposed for the corresponding liquid phase chemistry. PMID:16112432

Yang, Chen-Lu; McGarrahan, Jared

2005-12-01

411

Can dust coagulation trigger streaming instability?  

NASA Astrophysics Data System (ADS)

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.

Dr??kowska, J.; Dullemond, C. P.

2014-12-01

412

Intranasal exposure to amorphous nanosilica particles could activate intrinsic coagulation cascade and platelets in mice  

PubMed Central

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

2013-01-01

413

Binding of coagulation factor XI to washed human platelets  

SciTech Connect

The binding of human coagulation factor XI to washed human platelets was studied in the presence of zinc ions, calcium ions, and high molecular weight kininogen. Significant factor XI binding occurred at physiological levels of these metal ions when high molecular weight kininogen was present. Binding required platelet stimulation and was specific, reversible, and saturable. Scatchard analysis of the binding yielded approximately 1500 binding sites per platelet with an apparent dissociation constant of approximately 10 nM. Since the concentration of factor XI in plasma is about 25 nM, this suggests that in plasma factor XI binding sites on stimulated platelets might be saturated. Calcium ions and high molecular weight kininogen acted synergistically to enhance the ability of low concentrations of zinc ions to promote factor XI binding. The similarity between the concentrations of metal ions optimal for factor XI binding and those optimal for high molecular weight kininogen binding, as well as the ability of high molecular weight kininogen to modulate these metal ion effects, implies that factor XI and high molecular weight kininogen may form a complex on the platelet surface as they do in solution and on artificial negatively charged surfaces.

Greengard, J.S.; Heeb, M.J.; Ersdal, E.; Walsh, P.N.; Griffin, J.H.

1986-07-01

414

Isotopic studies of therapeutic anticoagulation with a coagulating enzyme  

PubMed Central

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

Bell, W. R.; Regoeczi, E.

1970-01-01

415

The anode mechanism of a thermal argon arc  

NASA Technical Reports Server (NTRS)

In order to clarify the anode mechanism in freely burning argon arcs, the anode drop was determined by probe measurements in the current intensity range of 10 to 200 A and arc lengths between 2 and 10 mm. Simultaneously, the power input at the anode was determined by measuring the temperature increase in the cooling water, using a thermoelement, and compared to the electrical output at the arc and in the anodic drop area. An anodic contraction was observed in the arc, at low current intensities. The results can be explained in terms of the effects of a cathodic plasma current, and in the contracted arc, in terms of an additional anodic plasma current.

Busz-Peuckert, G.; Finkelnburg, W.

1984-01-01

416

Etching with electron beam generated plasmas  

Microsoft Academic Search

A modulated electron beam generated plasma has been used to dry etch standard photoresist materials and silicon. Oxygen-argon mixtures were used to etch organic resist material and sulfur hexafluoride mixed with argon or oxygen was used for the silicon etching. Etch rates and anisotropy were determined with respect to gas compositions, incident ion energy (from an applied rf bias) and

D. Leonhardt; S. G. Walton; C. Muratore; R. F. Fernsler; R. A. Meger

2004-01-01

417

The Interface between Inflammation and Coagulation in Cardiovascular Disease  

PubMed Central

The intimate connection between coagulation and inflammation in the pathogenesis of vascular disease has moved more and more into focus of clinical research. This paper focuses on the essential components of this interplay in the settings of cardiovascular disease and acute coronary syndrome. Tissue factor, the main initiator of the extrinsic coagulation pathway, plays a central role via causing a proinflammatory response through activation of coagulation factors and thereby initiating coagulation and downstream cellular signalling pathways. Regarding activated clotting factors II, X, and VII, protease-activated receptors provide the molecular link between coagulation and inflammation. Hereby, PAR-1 displays deleterious as well as beneficial properties. Unravelling these interrelations may help developing new strategies to ameliorate the detrimental reciprocal aggravation of inflammation and coagulation. PMID:22518344

Demetz, Gabriele; Ott, Ilka

2012-01-01

418

Chronic HIV Disease and Activation of the Coagulation System  

PubMed Central

With current effective antiretroviral treatment, the spectrum of morbidity and mortality during chronic HIV disease has shifted away from AIDS defining clinical events. Persistent abnormalities in coagulation appear to contribute to excess risk for a broad spectrum of non-AIDS defining complications, including, but not limited to, venous and arterial thrombotic disease. Mechanisms specific to HIV disease, antiretroviral therapy, and lifestyle or behavioral factors contribute to a pro-coagulant state, in part, through increased tissue factor activity coupled with a paradoxical decline in the anti-coagulant response. Alterations in coagulation biology in the context of HIV disease appear to be largely a consequence of persistent systemic immune activation, micro- and macro-vascular disease, and, potentially, impaired hepatic synthesis of coagulation factors. The clinical consequences of HIV-related changes in coagulation biology, the degree to which they are unique to HIV disease, and whether they can be mitigated through adjunct treatments, remains a focus of current research. PMID:24034985

Baker, Jason V.

2014-01-01

419

Aversive reactions of turkeys to argon, carbon dioxide and a mixture of carbon dioxide and argon.  

PubMed

The reactions of turkeys to the presence of either 90 per cent argon in air (anoxia), 72 per cent carbon dioxide in air or a mixture of 30 per cent carbon dioxide and 60 per cent argon in air with 3 per cent residual oxygen were tested. The majority of the turkeys did not avoid a feeding chamber containing either argon or the mixture of carbon dioxide and argon, but 50 per cent of the turkeys avoided a feeding chamber containing 72 per cent carbon dioxide in air. It is concluded that from the point of view of welfare, either 90 per cent argon in air or a mixture of 30 per cent carbon dioxide and 60 per cent argon in air, would be preferable to a high concentration of carbon dioxide for stunning/killing turkeys. PMID:8799986

Raj, A B

1996-06-15

420

A Spatial-Temporal Model of Platelet Deposition and Blood Coagulation Under Flow  

Microsoft Academic Search

In the event of a vascular injury, a blood clot will form to prevent bleeding. This response involves two intertwined processes: platelet aggregation and coagulation. Activated platelets are critical to coagulation in that they provide localized reactive surfaces on which many of the coagulation reactions occur. The final product from the coagulation cascade directly couples the coagulation system to platelet

Karin Leiderman Gregg; Aaron Fogelson

2009-01-01

421

Recovery of struvite via coagulation and flocculation using natural compounds.  

PubMed

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

Latifian, Maryam; Liu, Jing; Mattiasson, Bo

2014-01-01

422

Compound bioflocculant and polyaluminum chloride in kaolin-humic acid coagulation: factors influencing coagulation performance and floc characteristics.  

PubMed

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

Li, Ruihua; Gao, Baoyu; Huang, Xin; Dong, Hongyu; Li, Xiaochen; Yue, Qinyan; Wang, Yan; Li, Qian

2014-11-01

423

A microwave plasma cleaning apparatus  

NASA Technical Reports Server (NTRS)

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.

Tsai, C. C.; Nelson, W. D.; Schechter, D. E.; Thompson, L. M.; Glover, A. L.

1995-01-01

424

Dielectronic recombination of boronlike argon  

NASA Astrophysics Data System (ADS)

We present measurements and calculations of ?n=0 dielectronic recombination resonances of boronlike argon between 0.2 and 6 eV. A storage ring equipped with an electron cooler was used for the measurements. Methods employed to reduce the electron energy distribution and improve the accuracy of resonance energy measurements have yielded an energy resolution of 30 meV full width at half maximum at low energies, and an energy uncertainty better than 30 meV. The high energy resolution results from the use of an adiabatic expansion technique to reduce the transverse electron energy distribution. The improved accuracy in energy determinations is achieved through the inclusion of variations in the ion velocity, which occur during scans of the electron velocity, in the relative velocity transformations. Calculations of the resonance strengths and energies were made using two different methods, multiconfiguration Dirac-Fock and multiconfiguration Breit-Pauli approximations. A comparison of the experimental data to the calculations shows fair agreement in both the spectral features and integrated intensities above 3 eV. However, poor agreement is found below 3 eV.

Dewitt, D. R.; Schuch, R.; Gao, H.; Zong, W.; Asp, S.; Biedermann, C.; Chen, M. H.; Badnell, N. R.

1996-04-01

425

Dust coagulation in protoplanetary disks: porosity matters  

E-print Network

Context: Sticking of colliding dust particles through van der Waals forces is the first stage in the grain growth process in protoplanetary disks, eventually leading to the formation of comets, asteroids and planets. A key aspect of the collisional evolution is the coupling between dust and gas motions, which depends on the internal structure (porosity) of aggregates. Aims: To quantify the importance of the internal structure on the collisional evolution of particles, and to create a new coagulation model to investigate the difference between porous and compact coagulation in the context of a turbulent protoplanetary disk. Methods: We have developed simple prescriptions for the collisional evolution of porosity of grain-aggregates in grain-grain collisions. Three regimes can then be distinguished: `hit-and-stick' at low velocities, with an increase in porosity; compaction at intermediate velocities, with a decrease of porosity; and fragmentation at high velocities. (..) Results: (..) We can discern three different stages in the particle growth process (..) We find that when compared to standard, compact models of coagulation, porous growth delays the onset of settling, because the surface area-to-mass ratio is higher, a consequence of the build-up of porosity during the initial stages. As a result, particles grow orders of magnitudes larger in mass before they rain-out to the mid-plane. Depending on the turbulent viscosity and on the position in the nebula, aggregates can grow to (porous) sizes of ~ 10 cm in a few thousand years. We also find that collisional energies are higher than in the limited PCA/CCA fractal models, thereby allowing aggregates to restructure. It is concluded that the microphysics of collisions plays a key role in the growth process.

C. W. Ormel; M. Spaans; A. G. G. M. Tielens

2006-10-02

426

Argon clusters embedded in helium nanodroplets.  

PubMed

Electron impact ionization of argon clusters embedded in helium droplets is investigated. Superior mass resolution makes it possible to distinguish between nominally isobaric cluster ions. An abundance maximum for ArHe(12)(+) is unambiguously confirmed; the spectra also prove the formation of Ar(2)He(n)(+) complexes that had been claimed to fragment into pure Ar(2)(+). Distributions of larger argon cluster ions containing up to 60 atoms closely resemble distributions observed upon electron impact or photoionization of bare argon clusters; caging and evaporative cooling provided by the helium matrix do not suffice to quench fragmentation of the nascent argon cluster ions. Intriguing abundance anomalies are observed in distributions of argon cluster ions that contain water, nitrogen or oxygen impurities. The strong abundance of Ar(55)H(2)O(+), Ar(54)O(2)(+) and Ar(54)N(2)(+) contrasts with the virtual absence of slightly larger cluster ions containing the corresponding impurities. The features are probably related to enhanced cluster ion stability upon closure of the second icosahedral shell but the difference in magic numbers (54 versus 55) and the well-known reactivity of charged argon-nitrogen complexes suggest structural differences. PMID:19851558

da Silva, Filipe Ferreira; Bartl, Peter; Denifl, Stephan; Echt, Olof; Märk, Tilmann D; Scheier, Paul

2009-11-14

427

Preparation and coagulation efficiency of polyaluminium ferric silicate chloride composite coagulant from wastewater of high-purity graphite production.  

PubMed

The aim of the present work was to produce a polyaluminium ferric silicate chloride (PAFSiC) coagulant from acidic and alkaline wastewater of purifying graphite by roasting, and subsequently to evaluate coagulation efficiency of the reagent by treating surface water from the Yellow River as well as municipal wastewater in comparison with the conventional coagulant polyaluminium chloride (PAC). The PAFSiC coagulant was prepared by co-polymerization. The effects of (Al+Fe)/Si molar ratio, OH/(Al+Fe) molar ratio (i.e., y value), coagulant dosage and pH value of test suspension on the coagulation behavior of FAFSiC and the stability of the PAFSiC were also examined. Results showed that PAFSiC performed more efficiently than PAC in removing turbidity, chemical oxygen demand (COD), and total phosphate (TP). The PAFSiC with a y value of 2.0 and (Al+Fe)/Si ratio of 5 (PAFSiC 2.0/5) showed excellent coagulation effect for both turbidity and COD, while PAFSiC 1.0/5 was the best for TP. The optimum coagulation pH range of PAFSiC 2.0/5 was 5.0-9.0, slightly wider than that of PAC (6.0-8.0). The process can be easily incorporated into high-purity graphite production plants, thereby reducing wastewater pollution and producing a valuable coagulant. PMID:22125904

Niu, Xiaoxia; Li, Xili; Zhao, Jihong; Ren, Yigang; Yang, Yanqin

2011-01-01

428

Coagulation profile and platelet parameters of the Arabian sand gazelle (Gazella subgutturosa marica): comparison with humans and camels.  

PubMed

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

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

429

The modeling of arsenic removal from contaminated water using coagulation and sorption  

E-print Network

To achieve predictive capability for complex environmental systems with coagulation and arsenic sorption, a unified improved coagulation model coupled with arsenic sorption was developed. A unified coagulation model coupled with arsenic sorption...

Kim, Jin-Wook

2005-11-01

430

Severe bleeding tendency caused by a rare complication of excessive fibrinolysis with disseminated intravascular coagulation in a 51-year-old Japanese man with prostate cancer: a case report  

PubMed Central

Introduction Disseminated intravascular coagulation causes thrombotic tendency leading to multiple organ failure and occurs in a wide variety of diseases including malignancy. Disseminated intravascular coagulation is a latent complication in people with prostate cancer. Case presentation A 51-year-old Japanese man with advanced castration-resistant prostate cancer was admitted to our hospital because of extensive purpura and severe anemia. Prolonged plasma coagulation time, hypofibrinogenemia and normal platelet count suggested that a decrease in fibrinogen induced a bleeding tendency causing purpura. However, elevated plasma levels of thrombin-antithrombin complex, fibrin and/or fibrinogen degradation products and D-dimers, with positive fibrin monomer test, manifested disseminated intravascular coagulation and subsequent fibrinolysis. Plasma levels of thrombin-antithrombin complex, fibrin and/or fibrinogen degradation products and D-dimers decreased after administration of low-molecular-weight heparin. However, low fibrinogen and ?2-antiplasmin levels were not improved and plasmin-antiplasmin complex did not decrease, which revealed excessive fibrinolysis complicated with disseminated intravascular coagulation. We suspected that prostate cancer cell-derived urokinase-type plasminogen activator caused excessive fibrinolysis. Administration of tranexamic acid for fibrinogenolysis was added together with high-dose anti-androgen therapy (fosfestrol) for prostate cancer. Thereafter, prostate-specific antigen and plasmin-antiplasmin complex decreased, followed by normalized fibrinogen and ?2-antiplasmin levels, and the patient eventually recovered from the bleeding tendency. Immunohistochemical staining of the biopsied prostate tissue exhibited that the prostate cancer cells produced tissue factor, the coagulation initiator, and urokinase-type plasminogen activator. Conclusion This patient with rare complications of disseminated intravascular coagulation and excessive fibrinolysis is a warning case of potential coagulation disorder onset in patients with prostate cancer. We propose that combined administration of tranexamic acid and low-molecular-weight heparin together with high-dose anti-androgen therapy is a useful therapeutic option for patients with this complicated coagulation disorder. PMID:23130841

2012-01-01

431

Modeling of Plasma Plume Induced During Laser Welding  

SciTech Connect

Theoretical modelling of the plasma plume induced during welding of iron sheets with CO2 laser are presented. The set of equations consists of equation of conservation of mass, energy, momentum and the diffusion equation and is solved with the use of commercially available program Fluent 6.2. The computations are made for the cases when the shielding gas is either argon or helium. The results show that in the case when argon is the shielding gas there are actually two plasmas; argon plasma and metal plasma.

Moscicki, T.; Hoffman, J.; Szymanski, Z. [Institute of Fundamental Technological Research, SwiePtokrzyska 21, 00-049 Warsaw (Poland)

2006-01-15

432

Transurethral laser coagulation of the prostate  

NASA Astrophysics Data System (ADS)

We describe the laser coagulation of the prostate using a conventional bare fiber inserted in a modified Albarran bridge which presents at the distal tip, a newly designed gold-plated reflector, connected by a deflecting mechanism. This allows delivery of laser energy (40 - 80 W) by direct reflection of the Nd:YAG laser light, an angularity more accentuated compared with other systems. Transurethral laser coagulation was performed on 25 patients for prostatic obstruction benign prostatic hyperplasia (BPH) and 6 selected patients for carcinoma of the prostate (December 91 - January 93). Patient selection (BPH) was limited to median lobe (range 50 - 55 years), small prostates, older and high-risk patients. Successful results were noted in 20 of the 25 cases of BPH group (80%). A significant reduction of obstructive symptoms was associated with an increase of maximal a medium flow rates. In the early prostate cancer group, the method has resulted in 3 patients with no evidence of disease, despite repeated biopsy, biochemical, and clinical investigations (PSA range level > 20 ng/ml to < 0.5 ng/ml at one year). The results are encouraging at this stage.

Mattioli, Stefano; Cremona, M.

1994-02-01

433

Increased coagulation and suppressed generation of activated protein C in aged mice during intra-abdominal sepsis.  

PubMed

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

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