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Sample records for microwave tissue coagulator

  1. A Numerical Study on Microwave Coagulation Therapy

    DTIC Science & Technology

    2013-01-01

    improvement of therapeutic effect. References [1] P. Prakash, “Theoretical Modeling for Hepatic Microwave Ablation ,” The Open Biomedical...A Numerical Study on Microwave Coagulation Therapy Amy J. Liu † , Hong Zhou * and Wei Kang * Department of Applied Mathematics Naval...is properly cited. Abstract Microwave coagulation therapy is a clinical technique for treating hepatocellular carcinoma (small size liver

  2. Microwave Tissue Ablation: Biophysics, Technology and Applications

    PubMed Central

    2010-01-01

    Microwave ablation is an emerging treatment option for many cancers, cardiac arrhythmias and other medical conditions. During treatment, microwaves are applied directly to tissues to produce rapid temperature elevations sufficient to produce immediate coagulative necrosis. The engineering design criteria for each application differ, with individual consideration for factors such as desired ablation zone size, treatment duration, and procedural invasiveness. Recent technological developments in applicator cooling, power control and system optimization for specific applications promise to increase the utilization of microwave ablation in the future. This article will review the basic biophysics of microwave tissue heating, provide an overview of the design and operation of current equipment, and outline areas for future research for microwave ablation. PMID:21175404

  3. Pathologic correlation study of microwave coagulation therapy for hepatic malignancies using a three-ring probe.

    PubMed

    Shen, Perry; Geisinger, Kim R; Zagoria, Ronald; Levine, Edward A

    2007-05-01

    Microwave coagulation therapy (MCT) for the ablation of unresectable hepatic malignancies is a promising alternative to radiofrequency and cryoablation techniques. There are few data on the clinical effectiveness of MCT. In vivo pathologic evaluation of ablated tumor tissue is not well described for the three-ring microwave probe. The study design was a prospective trial enrolling patients with resectable hepatic malignancies. Lesions underwent in vivo MCT with the three-ring probe prior to liver resection. Gross and histologic evaluations of the tumor were performed, including nicotinamide adenine dinucleotide (NADH) vital staining. A total of nine patients with metastatic colon cancer were enrolled and had NADH stains performed of their pathologic specimens. The median size of the metastasis being ablated was 3.5 cm (range, 1.5-12.3). Fifty-six percent of the tumors demonstrated evidence of spontaneous coagulative necrosis on immediate histologic examination. The median dimensions of the ablation zones were 5 cm (range, 3-7) x 4.5 cm (range, 2.5-5.2) x 4.2 cm (range, 2-5) with a 5-min ablation at 60 W. The median ablation volume was 50.6 cm3 (range, 9-78). NADH vital staining was performed of the ablation zones with 100% absence of staining in the tumor tissue and in benign hepatic parenchyma, which is consistent with irreversible cellular damage. In conclusion, in vivo MCT of hepatic malignancies with the three-ring probe produces nonviable tumor cells after a 5-min ablation. The ablation time is significantly shorter than other available ablative techniques. Immediate histologic exam produces some evidence of coagulative necrosis. Further study of this promising technology is warranted.

  4. Regulation of tissue factor coagulant activity on cell surfaces

    PubMed Central

    RAO, L.V.M.; PENDURTHI, U.R.

    2012-01-01

    Summary Tissue factor (TF) is a transmembrane glycoprotein and an essential component of factor VIIa-TF enzymatic complex that triggers activation of the coagulation cascade. Formation of TF-FVIIa complexes on cell surfaces not only trigger the coagulation cascade but also transduce cell signaling via activation of protease-activated receptors. Tissue factor is expressed constitutively on cell surfaces of a variety of extravascular cell types, including fibroblasts and pericytes in and surrounding blood vessel walls and epithelial cells but generally absent on cells that come in contact with blood directly. However, TF expression could be induced in some blood cells, such as monocytes and endothelial cells, following an injury or pathological stimuli. Tissue factor is essential for hemostasis, but aberrant expression of TF leads to thrombosis. Therefore, a proper regulation of TF activity is critical for the maintenance of hemostatic balance and health in general. TF-FVIIa coagulant activity at the cell surface is influenced not only by TF protein expression levels but also independently by a variety of mechanisms, including alterations in membrane phospholipid composition and cholesterol content, thiol-dependent modifications of TF allosteric disulfide bond, and other post-translational modifications of TF. In this article, we critically review key literature on mechanisms by which TF coagulant activity is regulated at the cell surface in the absence of changes in TF protein levels with specific emphasis on recently published data and provide the authors’ perspective on the subject. PMID:23006890

  5. Endoscopic microwave coagulation therapy of postoperative hemorrhage from a stapled anastomosis.

    PubMed

    Umano, Yasukazu; Horiuchi, Tetsuya; Inoue, Masaya; Shono, Yoshiharu; Oku, Yoshimasa; Tanishima, Hiroyuki; Tsuji, Takeshi; Tabuse, Katsuyoshi

    2005-01-01

    We experienced three cases of postoperative hemorrhage from a stapled gastrointestinal anastomosis, and established endoscopic microwave coagulation therapy (EMCT) with a cylinder-type electrode. We were able to treat postoperative hemorrhage over the entire circumference of stapled anastomosis successfully. Two patients had undergone a lower third thoracic esophagogastrectomy through a left thoraco-abdominal approach for gastric cancer in the cardia, while the other case had undergone Billroth I gastrectomy. They each had fresh bleeding from the stapled anastomosis after the operation. Emergency endoscopic examination was immediately performed. Endoscopy revealed bleeding on the suture line. We performed hemostasis endoscopically with microwave coagulation therapy safely. They were discharged from the hospital without complications such as leakage and stenosis. Since EMCT with the cylinder-type electrode can coagulate shallowly and widely, it is very effective for hemorrhage from a stapled anastomosis.

  6. Effects of microwave radiation on living tissues

    SciTech Connect

    Surrell, J.A.; Alexander, R.C.; Cohle, S.D.; Lovell, F.R. Jr.; Wehrenberg, R.A.

    1987-08-01

    Prompted by an alleged case of child abuse resulting from microwave oven burns and the discovery of one other case, an animal model was chosen to explore microwave burn characteristics upon living, perfusing tissue. Anesthetized piglets were exposed to radiation from a standard household microwave oven for varying lengths of time, sufficient to result in full-thickness skin and visceral burns. Characteristic burn patterns were grossly identified. Biopsies studied with both light and electron microscopy demonstrated a pattern of relative layered tissue sparing. Layered tissue sparing is characterized by burned skin and muscle, with relatively unburned subcutaneous fat between these two layers. These findings have important forensic and patient care implications.

  7. Laser probes for noninvasive coagulation of subsurface tissues

    NASA Astrophysics Data System (ADS)

    Chung, Chia-Chun; Permpongkosol, Sompol; Varkarakis, Ioannis M.; Lima, Guilherme; Franco, Nicholas; Hayman, Michael H.; Nicol, Theresa; Fried, Nathaniel M.

    2006-02-01

    Previous ex vivo tissue studies utilizing deep laser heating combined with contact cooling of the tissue surface produced noninvasive thermal destruction of subsurface tissue structures in skin and liver samples. This study describes the design and preliminary in vivo testing of two integrated laser/cooling probes for simultaneous Nd:YAG laser irradiation and sapphire contact cooling of liver and skin tissues in an in vivo, acute porcine model for potential use in laparoscopic and endoscopic surgery. Nd:YAG laser radiation with a wavelength of 1.06 μm, power of 20 W, 7.5-mm-diameter spot, 500-ms pulse length, and repetition rate of 0.625 Hz, was delivered to the tissue with a total irradiation time of 16 s. The tissue surface was continuously cooled with a sapphire plate maintained at -5 °C, and with pre- and post-ablation cooling times measuring 120 s and 30 s, resulting in a total operation time of 166 s per a lesion. Thermal lesions were created in liver and skin at a 1-mm depth below the tissue surface and with a 3-4 mm diameter. The laser parameters and lesion dimensions were comparable to previous ex vivo tissue studies. Preliminary in vivo animal studies demonstrate noninvasive creation of subsurface thermal lesions in tissue using Nd:YAG laser irradiation in conjunction with sapphire contact cooling. Chronic wound healing studies will be necessary to optimize the laser and cooling parameters. Potential clinical applications include endoscopic laser treatment of female stress urinary incontinence and thermal coagulation of early stage bladder tumors.

  8. Microwave Tissue Soldering for Immediate Wound Closure

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey; Ngo, Phong H.; Plan, Chau T.; Byerly, Diane; Dusl, John; Sognier, Marguerite A.

    2011-01-01

    A novel approach for the immediate sealing of traumatic wounds is under development. A portable microwave generator and handheld antenna are used to seal wounds, binding the edges of the wound together using a biodegradable protein sealant or solder. This method could be used for repairing wounds in emergency settings, by restoring the wound surface to its original strength within minutes. This technique could also be utilized for surgical purposes involving solid visceral organs (i.e., liver, spleen, and kidney) that currently do not respond well to ordinary surgical procedures. A miniaturized microwave generator and a handheld antenna are used to deliver microwave energy to the protein solder, which is applied to the wound. The antenna can be of several alternative designs optimized for placement either in contact with or proximity to the protein solder covering the wound. In either case, optimization of the design includes the matching of impedances to maximize the energy delivered to the protein solder and wound at a chosen frequency. For certain applications, an antenna could be designed that would emit power only when it is in direct contact with the wound. The optimum frequency or frequencies for a specific application would depend on the required depth of penetration of the microwave energy. In fact, a computational simulation for each specific application could be performed, which would then match the characteristics of the antenna with the protein solder and tissue to best effect wound closure. An additional area of interest with potential benefit that remains to be validated is whether microwave energy can effectively kill bacteria in and around the wound. Thus, this may be an efficient method for simultaneously sterilizing and closing wounds. Using microwave energy to seal wounds has a number of advantages over lasers, which are currently in experimental use in some hospitals. Laser tissue welding is unsuitable for emergency use because its large, bulky

  9. Hepatocyte tissue factor activates the coagulation cascade in mice

    PubMed Central

    Sullivan, Bradley P.; Kopec, Anna K.; Joshi, Nikita; Cline, Holly; Brown, Juliette A.; Bishop, Stephanie C.; Kassel, Karen M.; Rockwell, Cheryl; Mackman, Nigel

    2013-01-01

    In this study, we characterized tissue factor (TF) expression in mouse hepatocytes (HPCs) and evaluated its role in mouse models of HPC transplantation and acetaminophen (APAP) overdose. TF expression was significantly reduced in isolated HPCs and liver homogenates from TFflox/flox/albumin-Cre mice (HPCΔTF mice) compared with TFflox/flox mice (control mice). Isolated mouse HPCs expressed low levels of TF that clotted factor VII-deficient human plasma. In addition, HPC TF initiated factor Xa generation without exogenous factor VIIa, and TF activity was increased dramatically after cell lysis. Treatment of HPCs with an inhibitory TF antibody or a cell-impermeable lysine-conjugating reagent prior to lysis substantially reduced TF activity, suggesting that TF was mainly present on the cell surface. Thrombin generation was dramatically reduced in APAP-treated HPCΔTF mice compared with APAP-treated control mice. In addition, thrombin generation was dependent on donor HPC TF expression in a model of HPC transplantation. These results suggest that mouse HPCs constitutively express cell surface TF that mediates activation of coagulation during hepatocellular injury. PMID:23305736

  10. Sequential coagulation factor VIIa domain binding to tissue factor

    SciTech Connect

    Oesterlund, Maria; Persson, Egon; Freskgard, Per-Ola . E-mail: msv@ifm.liu.se

    2005-12-02

    Vessel wall tissue factor (TF) is exposed to blood upon vascular damage which enables association with factor VIIa (FVIIa). This leads to initiation of the blood coagulation cascade through localization and allosteric induction of FVIIa procoagulant activity. To examine the docking pathway of the FVIIa-TF complex, various residues in the extracellular part of TF (sTF) that are known to interact with FVIIa were replaced with cysteines labelled with a fluorescent probe. By using stopped-flow fluorescence kinetic measurements in combination with surface plasmon resonance analysis, we studied the association of the resulting sTF variants with FVIIa. We found the docking trajectory to be a sequence of events in which the protease domain of FVIIa initiates contact with sTF. Thereafter, the two proteins are tethered via the first epidermal growth factor-like and finally the {gamma}-carboxyglutamic acid (Gla) domain. The two labelled sTF residues interacting with the protease domain of FVIIa bind or become eventually ordered at different rates, revealing kinetic details pertinent to the allosteric activation of FVIIa by sTF. Moreover, when the Gla domain of FVIIa is removed the difference in the rate of association for the remaining domains is much more pronounced.

  11. Using microfluidics to understand the effect of spatial distribution of tissue factor on blood coagulation.

    PubMed

    Shen, Feng; Kastrup, Christian J; Ismagilov, Rustem F

    2008-01-01

    Initiation of blood coagulation by tissue factor (TF) is a robust, highly regulated process. Both the spatial distribution of TF and the geometry of the vasculature may play important roles in regulating coagulation. As this review describes, microfluidic systems provide a unique opportunity for investigating the spatiotemporal dynamics of blood coagulation in vitro. Microfluidic systems with surfaces of phospholipid bilayers patterned with TF have been used to demonstrate experimentally the threshold responses of initiation of coagulation to the size and shape of surfaces presenting TF. These systems have also been used to demonstrate experimentally that propagation of coagulation is regulated by the shear rate of blood flow in microcapillaries and microchannels. By understanding these and other aspects of the spatial dynamics that regulate blood coagulation, many new methods for treating clotting disorders, such as venous thromboembolism (VTE) and sepsis, could arise.

  12. Microwave Tissue Soldering for Immediate Wound Closure

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey; Ngo, Phong H.; Phan, Chau T.; Byerly, Diane; Dusl, John; Sognier, Marguerite A.; Carl, James

    2011-01-01

    A novel approach for the immediate sealing of traumatic wounds is under development. A portable microwave generator and handheld antenna are used to seal wounds, binding the edges of the wound together using a biodegradable protein sealant or solder. This method could be used for repairing wounds in emergency settings by restoring the wound surface to its original strength within minutes. This technique could also be utilized for surgical purposes involving solid visceral organs (i.e., liver, spleen, and kidney) that currently do not respond well to ordinary surgical procedures. A miniaturized microwave generator and a handheld antenna are used to deliver microwave energy to the protein solder, which is applied to the wound. The antenna can be of several alternative designs optimized for placement either in contact with or in proximity to the protein solder covering the wound. In either case, optimization of the design includes the matching of impedances to maximize the energy delivered to the protein solder and wound at a chosen frequency. For certain applications, an antenna could be designed that would emit power only when it is in direct contact with the wound. The optimum frequency or frequencies for a specific application would depend on the required depth of penetration of the microwave energy. In fact, a computational simulation for each specific application could be performed, which would then match the characteristics of the antenna with the protein solder and tissue to best effect wound closure. An additional area of interest with potential benefit that remains to be validated is whether microwave energy can effectively kill bacteria in and around the wound. Thus, this may be an efficient method for simultaneously sterilizing and closing wounds.

  13. Microwave soft tissue ablation (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Clegg, Peter J.; Cronin, Nigel J.

    2005-04-01

    Microsulis, in conjunction with the University of Bath have developed a set of novel microwave applicators for the ablation of soft tissues. These interstitial applicators have been designed for use in open surgical, laparoscopic and percutaneous settings and range in diameter from 2.4 to 7 mm. A 20 mm diameter flat faced interface applicator was developed as an adjunct to the open surgical interstitial applicator and has been applied to the treatment of surface breaking lesions in hepatobiliary surgery. Taken as a complete tool set the applicators are capable of treating a wide range of conditions in a safe and efficacious manner. The modality employs a radiated electromagnetic field at the allocated medical frequency of 2.45 GHz and powers between 30 and 150 Watts. Computer simulations, bench testing, safety and efficacy testing, ex-vivo and in-vivo work plus clinical trials have demonstrated that these systems are capable of generating large volumes of ablation in short times with favourable ablation geometries. Clinical studies have shown very low complication rates with minimal local recurrence. It is considered that this modality offers major advantages over currently marketed products. The technique is considered to be particularly safe as it is quick and there is no passage of current obviating the requirement for grounding pads. Since the microwave field operates primarily on water and all soft tissues with the exception of fat are made up of approximately 70% water the heating pattern is highly predictable making repeatability a key factor for this modality.

  14. Tissue factor as an initiator of coagulation and inflammation in the lung.

    PubMed

    van der Poll, Tom

    2008-01-01

    Patients with severe infections almost invariably exhibit evidence of activation of the coagulation system. The lungs are amongst the most frequently affected organs during severe infection and sepsis. The abundant presence of intravascular and extravascular fibrin appears to be a specific hallmark of acute lung injury after sepsis. Tissue factor (TF) is regarded to be the primary initiator of coagulation in severe infection. Effective blockade of the TF pathway, either by recombinant TF pathway inhibitor or by anti-TF antibodies in experimental sepsis, attenuates lung injury and partially prevents pulmonary dysfunction. In addition, inhibition of the activity of TF prevents local activation of coagulation in models of pneumonia. The TF pathway can influence inflammatory signaling by activation of protease activated receptor-1 and -2. This review presents the most recent data on the crosstalk between TF-mediated coagulation and inflammation, with a specific emphasis on these processes in the lung.

  15. Differential roles of tissue factor and phosphatidylserine in activation of coagulation.

    PubMed

    Spronk, Henri M H; ten Cate, Hugo; van der Meijden, Paola E J

    2014-05-01

    It has been suggested that the main physiological trigger of coagulation, tissue factor, possesses limited procoagulant activity and occurs in an inactive or so-called encrypted state. For the conversion of encrypted into decrypted tissue factor with sufficient procoagulant activity, four distinct models have been proposed: 1; dimer formation, 2; lipid rafts, 3; disulfide bonds, and 4; phosphatidylserine exposure. Pro and cons can be given for each of these mechanisms of tissue factor encryption/decryption, however, it seems most likely that two or more mechanisms act together in activating the procoagulant activity. The exposure of phosphatidylserine in the outer layer of cell membranes supports coagulation through enhanced formation of the tenase (factors IXa, VIIIa and X) and prothrombinase (factors Xa, Va and prothrombin) complexes. The proposed role for phosphatidylserine in decryption of tissue factor could contribute to the correct orientation of the tissue factor - factor VII complex. Overall, the contribution of both tissue factor and phosphatidylserine to coagulation seems distinct with tissue factor being the physiological activator and phosphatidylserine the driving force of propagation of coagulation.

  16. Matriptase activation connects tissue factor-dependent coagulation initiation to epithelial proteolysis and signaling.

    PubMed

    Le Gall, Sylvain M; Szabo, Roman; Lee, Melody; Kirchhofer, Daniel; Craik, Charles S; Bugge, Thomas H; Camerer, Eric

    2016-06-23

    The coagulation cascade is designed to sense tissue injury by physical separation of the membrane-anchored cofactor tissue factor (TF) from inactive precursors of coagulation proteases circulating in plasma. Once TF on epithelial and other extravascular cells is exposed to plasma, sequential activation of coagulation proteases coordinates hemostasis and contributes to host defense and tissue repair. Membrane-anchored serine proteases (MASPs) play critical roles in the development and homeostasis of epithelial barrier tissues; how MASPs are activated in mature epithelia is unknown. We here report that proteases of the extrinsic pathway of blood coagulation transactivate the MASP matriptase, thus connecting coagulation initiation to epithelial proteolysis and signaling. Exposure of TF-expressing cells to factors (F) VIIa and Xa triggered the conversion of latent pro-matriptase to an active protease, which in turn cleaved the pericellular substrates protease-activated receptor-2 (PAR2) and pro-urokinase. An activation pathway-selective PAR2 mutant resistant to direct cleavage by TF:FVIIa and FXa was activated by these proteases when cells co-expressed pro-matriptase, and matriptase transactivation was necessary for efficient cleavage and activation of wild-type PAR2 by physiological concentrations of TF:FVIIa and FXa. The coagulation initiation complex induced rapid and prolonged enhancement of the barrier function of epithelial monolayers that was dependent on matriptase transactivation and PAR2 signaling. These observations suggest that the coagulation cascade engages matriptase to help coordinate epithelial defense and repair programs after injury or infection, and that matriptase may contribute to TF-driven pathogenesis in cancer and inflammation.

  17. Two-wavelength approach for control of coagulation depth during laser tissue soldering

    NASA Astrophysics Data System (ADS)

    Wehner, Martin; Aden, Mirko; Toedter, Nina; Rosenkranz, Beate

    2015-03-01

    In laser tissue soldering (LTS) protein solutions are used for closing of incisions or fixation of wound dressings. During coagulation and thermal denaturation of the protein solutions their morphology changes significantly such that light is strongly scattered. When scattering becomes major component extinction increases and the optical penetration depth shrinks which could lead to unsufficient coagulation and bonding. For adaption of extinction during coagulation we are investigating a two-wavelength approach. A strongly absorbed laser wavelength (1540 nm) and weakly absorbed wavelength (980 nm) can be applied simultaneously. Simulation of beam propagation is performed in natural and coagulated state of the solder. The model describes a three-layer system consisting of membrane, solder and phantom. The optical properties are determined by spectrometric measurements both in natural and coagulated state. The absorption coefficient μa, scattering coefficient μs and anisotropy factor γ are determined by numerical analysis from the spectrometric data. Beam propagation is simulated for 980 nm and 1540 nm radiation with ZEMAX® software based on the Monte Carlo method. For both wavelengths the beginning of the process with a clear solder layer, and the final state characterized by a coagulated solder layer are examined. The optical penetration depth depends mainly on the optical properties of the solder, which change in the course of coagulation process. The coagulation depth can be varied between 1.5 mm to 3.5 mm by changing the proportion of both laser sources. This leads to concepts for minimizing heat input while maintaining a constant coagulation depth.

  18. [Examination of percutaneous microwave coagulation and radiofrequency ablation therapy for metastatic liver cancer].

    PubMed

    Ohkawa, Shinichi; Hirokawa, Satoru; Masaki, Takahiro; Miyakawa, Kaoru; Tarao, Kazuo; Akaike, Makoto; Sugimasa, Yukio; Takemiya, Shoji; Sairenji, Motonori; Motohashi, Hisahiko

    2002-11-01

    Percutaneous microwave coagulation therapy (PMCT) and radio frequency ablation therapy (RFA) as treatments for metastatic liver cancer were examined. PMCT or RFA was administered for 18 metastatic liver cancer lesions (primary lesion: 11 colon rectal cancer, one esophagus cancer, one thyroid cancer, one pancreatic cancer, one pheochromocytoma) in 16 patients from July 1999 to March 2002. RFA was performed 1 time for 12 minutes in principle, using a Cool-tip RF system from Radionics. Patients had a mean age of 58.8 years and the mean diameter of the neoplasms was about 22 mm. Critical complications were not seen. The rate of partial recurrence was 35.3% as of March, 2002, in an average observation period of 7.3 months. On the other hand, with the medical treatment for the hepatocellular carcinoma provided during this period, the rate of partial recurrence was 14.8%. The treatment of metastatic liver cancer by PMCT and RFA is associated with a high rate of a recurrence as compared with hepatocellular carcinoma, and needs to be examined to discover ways of adaptation and improvement of the technology.

  19. Laser tissue coagulation and concurrent optical coherence tomography through a double-clad fiber coupler.

    PubMed

    Beaudette, Kathy; Baac, Hyoung Won; Madore, Wendy-Julie; Villiger, Martin; Godbout, Nicolas; Bouma, Brett E; Boudoux, Caroline

    2015-04-01

    Double-clad fiber (DCF) is herein used in conjunction with a double-clad fiber coupler (DCFC) to enable simultaneous and co-registered optical coherence tomography (OCT) and laser tissue coagulation. The DCF allows a single channel fiber-optic probe to be shared: i.e. the core propagating the OCT signal while the inner cladding delivers the coagulation laser light. We herein present a novel DCFC designed and built to combine both signals within a DCF (>90% of single-mode transmission; >65% multimode coupling). Potential OCT imaging degradation mechanisms are also investigated and solutions to mitigate them are presented. The combined DCFC-based system was used to induce coagulation of an ex vivo swine esophagus allowing a real-time assessment of thermal dynamic processes. We therefore demonstrate a DCFC-based system combining OCT imaging with laser coagulation through a single fiber, thus enabling both modalities to be performed simultaneously and in a co-registered manner. Such a system enables endoscopic image-guided laser marking of superficial epithelial tissues or laser thermal therapy of epithelial lesions in pathologies such as Barrett's esophagus.

  20. Microwave non-contact imaging of subcutaneous human body tissues

    PubMed Central

    Chernokalov, Alexander; Khripkov, Alexander; Cho, Jaegeol; Druchinin, Sergey

    2015-01-01

    A small-size microwave sensor is developed for non-contact imaging of a human body structure in 2D, enabling fitness and health monitoring using mobile devices. A method for human body tissue structure imaging is developed and experimentally validated. Subcutaneous fat tissue reconstruction depth of up to 70 mm and maximum fat thickness measurement error below 2 mm are demonstrated by measurements with a human body phantom and human subjects. Electrically small antennas are developed for integration of the microwave sensor into a mobile device. Usability of the developed microwave sensor for fitness applications, healthcare, and body weight management is demonstrated. PMID:26609415

  1. Microwave non-contact imaging of subcutaneous human body tissues.

    PubMed

    Kletsov, Andrey; Chernokalov, Alexander; Khripkov, Alexander; Cho, Jaegeol; Druchinin, Sergey

    2015-10-01

    A small-size microwave sensor is developed for non-contact imaging of a human body structure in 2D, enabling fitness and health monitoring using mobile devices. A method for human body tissue structure imaging is developed and experimentally validated. Subcutaneous fat tissue reconstruction depth of up to 70 mm and maximum fat thickness measurement error below 2 mm are demonstrated by measurements with a human body phantom and human subjects. Electrically small antennas are developed for integration of the microwave sensor into a mobile device. Usability of the developed microwave sensor for fitness applications, healthcare, and body weight management is demonstrated.

  2. Modeling and analysis of coagulated liver tissue and its interaction with a scalpel blade.

    PubMed

    Leong, Florence; Huang, Wei-Hsuan; Chui, Chee-Kong

    2013-06-01

    Radiofrequency-assisted methods have been used in hepatectomy--the resection process of removing liver tissue which encapsulates the tumor from the liver organ. A prototype was built to enable smooth surgical transition between radiofrequency ablation and liver resection. There is a lack of literature on mechanical properties of radiofrequency-ablated liver tissue and the tool-tissue interaction during cutting. This led to our study on coagulated tissue mechanical properties and modeling of its dynamic interaction with a scalpel blade. A novel mechanical model was proposed to mimic the mechanical behavior of radiofrequency-ablated liver tissue. The model is able to account for the viscoelastic behavior of the ablated tissue in both compression and relaxation tests. Experiments were performed to validate the proposed model. In addition, a knife blade-tissue interaction model is proposed to demonstrate the potential of integrating the proposed model for application in device design.

  3. Physiological levels of blood coagulation factors IX and X control coagulation kinetics in an in vitro model of circulating tissue factor

    NASA Astrophysics Data System (ADS)

    Tormoen, Garth W.; Khader, Ayesha; Gruber, András; McCarty, Owen J. T.

    2013-06-01

    Thrombosis significantly contributes to cancer morbidity and mortality. The mechanism behind thrombosis in cancer may be circulating tissue factor (TF), as levels of circulating TF are associated with thrombosis. However, circulating TF antigen level alone has failed to predict thrombosis in patients with cancer. We hypothesize that coagulation factor levels regulate the kinetics of circulating TF-induced thrombosis. Coagulation kinetics were measured as a function of individual coagulation factor levels and TF particle concentration. Clotting times increased when pooled plasma was mixed at or above a ratio of 4:6 with PBS. Clotting times increased when pooled plasma was mixed at or above a ratio of 8:2 with factor VII-depleted plasma, 7:3 with factor IX- or factor X-depleted plasmas, or 2:8 with factor II-, V- or VIII-depleted plasmas. Addition of coagulation factors VII, X, IX, V and II to depleted plasmas shortened clotting and enzyme initiation times, and increased enzyme generation rates in a concentration-dependent manner. Only additions of factors IX and X from low-normal to high-normal levels shortened clotting times and increased enzyme generation rates. Our results demonstrate that coagulation kinetics for TF particles are controlled by factor IX and X levels within the normal physiological range. We hypothesize that individual patient factor IX and X levels may be prognostic for susceptibility to circulating TF-induced thrombosis.

  4. Methods and apparatus for microwave tissue welding for wound closure

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Ngo, Phong H. (Inventor); Phan, Chau T. (Inventor); Byerly, Diane L. (Inventor); Dusl, John R. (Inventor); Sognier, Marguerite A. (Inventor); Carl, James R. (Inventor)

    2013-01-01

    Methods and apparatus for joining biological tissue together are provided. In at least one specific embodiment, a method for joining biological tissue together can include applying a biological solder on a wound. A barrier layer can be disposed on the biological solder. An antenna can be located in proximate spatial relationship to the barrier layer. An impedance of the antenna can be matched to an impedance of the wound. Microwaves from a signal generator can be transmitted through the antenna to weld two or more biological tissue pieces of the wound together. A power of the microwaves can be adjusted by a control circuit disposed between the antenna and the signal generator. The heating profile within the tissue may be adjusted and controlled by the placement of metallic microspheres in or around the wound.

  5. Microwave Ablation Compared with Radiofrequency Ablation for Breast Tissue in an Ex Vivo Bovine Udder Model

    SciTech Connect

    Tanaka, Toshihiro; Westphal, Saskia; Isfort, Peter; Braunschweig, Till; Penzkofer, Tobias Bruners, Philipp; Kichikawa, Kimihiko; Schmitz-Rode, Thomas Mahnken, Andreas H.

    2012-08-15

    Purpose: To compare the effectiveness of microwave (MW) ablation with radiofrequency (RF) ablation for treating breast tissue in a nonperfused ex vivo model of healthy bovine udder tissue. Materials and Methods: MW ablations were performed at power outputs of 25W, 35W, and 45W using a 915-MHz frequency generator and a 2-cm active tip antenna. RF ablations were performed with a bipolar RF system with 2- and 3-cm active tip electrodes. Tissue temperatures were continuously monitored during ablation. Results: The mean short-axis diameters of the coagulation zones were 1.34 {+-} 0.14, 1.45 {+-} 0.13, and 1.74 {+-} 0.11 cm for MW ablation at outputs of 25W, 35W, and 45W. For RF ablation, the corresponding values were 1.16 {+-} 0.09 and 1.26 {+-} 0.14 cm with electrodes having 2- and 3-cm active tips, respectively. The mean coagulation volumes were 2.27 {+-} 0.65, 2.85 {+-} 0.72, and 4.45 {+-} 0.47 cm{sup 3} for MW ablation at outputs of 25W, 35W, and 45W and 1.18 {+-} 0.30 and 2.29 {+-} 0.55 cm{sup 3} got RF ablation with 2- and 3-cm electrodes, respectively. MW ablations at 35W and 45W achieved significantly longer short-axis diameters than RF ablations (P < 0.05). The highest tissue temperature was achieved with MW ablation at 45W (P < 0.05). On histological examination, the extent of the ablation zone in MW ablations was less affected by tissue heterogeneity than that in RF ablations. Conclusion: MW ablation appears to be advantageous with respect to the volume of ablation and the shape of the margin of necrosis compared with RF ablation in an ex vivo bovine udder.

  6. Tissue factor and tissue factor pathway inhibitor as key regulators of global hemostasis: measurement of their levels in coagulation assays.

    PubMed

    Kasthuri, Raj S; Glover, Sam L; Boles, Jeremiah; Mackman, Nigel

    2010-10-01

    The tissue factor (TF)/factor (F)VIIa complex is the primary initiator of coagulation in vivo. Tissue factor pathway inhibitor (TFPI) is the physiological inhibitor of the TF/FVIIa complex. Deficiencies of either TF or TFPI have not been reported in humans, and a complete absence of either of these two proteins in mice is embryonically lethal. To maintain normal hemostasis, levels of TF and TFPI need to be balanced. Increased levels of TF can overwhelm the inhibitory capacity of TFPI, resulting in thrombosis. Decreased levels of TF are associated with bleeding. Global assays of coagulation are defined as tests capable of evaluating all components of the clotting cascade that are present in plasma. In these tests the thrombogenic surface is either provided by platelets or exogenous phospholipids. Clotting assays currently used in clinical practice are not designed to measure endogenous levels of TF and TFPI. Therefore, there is a need to develop sensitive and specific assays for measuring levels of functional TF and TFPI in whole blood and plasma. These assays could be useful in patient management in many scenarios.

  7. Coagulation factor V mediates inhibition of tissue factor signaling by activated protein C in mice

    PubMed Central

    Liang, Hai Po H.; Kerschen, Edward J.; Basu, Sreemanti; Hernandez, Irene; Zogg, Mark; Jia, Shuang; Hessner, Martin J.; Toso, Raffaella; Rezaie, Alireza R.; Fernández, José A.; Camire, Rodney M.; Ruf, Wolfram; Griffin, John H.

    2015-01-01

    The key effector molecule of the natural protein C pathway, activated protein C (aPC), exerts pleiotropic effects on coagulation, fibrinolysis, and inflammation. Coagulation-independent cell signaling by aPC appears to be the predominant mechanism underlying its highly reproducible therapeutic efficacy in most animal models of injury and infection. In this study, using a mouse model of Staphylococcus aureus sepsis, we demonstrate marked disease stage–specific effects of the anticoagulant and cell signaling functions of aPC. aPC resistance of factor (f)V due to the R506Q Leiden mutation protected against detrimental anticoagulant effects of aPC therapy but also abrogated the anti-inflammatory and mortality-reducing effects of the signaling-selective 5A-aPC variant that has minimal anticoagulant function. We found that procofactor V (cleaved by aPC at R506) and protein S were necessary cofactors for the aPC-mediated inhibition of inflammatory tissue-factor signaling. The anti-inflammatory cofactor function of fV involved the same structural features that govern its cofactor function for the anticoagulant effects of aPC, yet its anti-inflammatory activities did not involve proteolysis of activated coagulation factors Va and VIIIa. These findings reveal a novel biological function and mechanism of the protein C pathway in which protein S and the aPC-cleaved form of fV are cofactors for anti-inflammatory cell signaling by aPC in the context of endotoxemia and infection. PMID:26341257

  8. Investigation for role of tissue factor and blood coagulation system in severe acute pancreatitis and associated liver injury.

    PubMed

    Ou, Zhi-Bing; Miao, Chun-Mu; Ye, Ming-Xin; Xing, Ding-Pei; He, Kun; Li, Pei-Zhi; Zhu, Rong-Tao; Gong, Jian-Ping

    2017-01-01

    This study aims to investigate the molecular mechanisms underlying the pathogenesis of severe acute pancreatitis (SAP) and SAP-associated liver injury, we performed an association analysis of the functions of tissue factor (TF) and blood coagulation system in both SAP patients and mouse SAP model. Our results showed that serum TF and tissue factor-microparticle (TF-MP) levels were highly up-regulated in both SAP patients and SAP mouse model, which was accompanied by the dysfunction of blood coagulation system. Besides, TF expression was also highly up-regulated in the Kupffer cells (KCs) of SAP mouse model. After inhibiting KCs in SAP mouse model, the amelioration of blood coagulation system functions was associated with the decrease in serum TF and TF-MPs levels, and the reduction of SAP-associated liver injury was associated with the decrease of TF expression in KCs. In conclusion, the dis-regulated TF expression and associated dysfunction of blood coagulation system are critical factors for the pathogenesis of SAP and SAP-associated liver injury. TF may serve as a potential and effective target for treating SAP and SAP-associated liver injury.

  9. Silicon micromachined ultrasonic scalpel for the dissection and coagulation of tissue.

    PubMed

    Lockhart, R; Friedrich, F; Briand, D; Margairaz, P; Sandoz, J-P; Brossard, J; Keppner, H; Olson, W; Dietz, T; Tardy, Y; Meyer, H; Stadelmann, P; Robert, C; Boegli, A; Farine, P-A; de Rooij, N F; Burger, J

    2015-08-01

    This work presents a planar, longitudinal mode ultrasonic scalpel microfabricated from monocrystalline silicon wafers. Silicon was selected as the material for the ultrasonic horn due to its high speed of sound and thermal conductivity as well as its low density compared to commonly used titanium based alloys. Combined with a relatively high Young's modulus, a lighter, more efficient design for the ultrasonic scalpel can be implemented which, due to silicon batch manufacturing, can be fabricated at a lower cost. Transverse displacement of the piezoelectric actuators is coupled into the planar silicon structure and amplified by its horn-like geometry. Using finite element modeling and experimental displacement and velocity data as well as cutting tests, key design parameters have been identified that directly influence the power efficiency and robustness of the device as well as its ease of controllability when driven in resonance. Designs in which the full- and half-wave transverse modes of the transducer are matched or not matched to the natural frequencies of the piezoelectric actuators have been evaluated. The performance of the Si micromachined scalpels has been found to be comparable to existing commercial titanium based ultrasonic scalpels used in surgical operations for efficient dissection of tissue as well as coaptation and coagulation of tissue for hemostasis. Tip displacements (peak-to-peak) of the scalpels in the range of 10-50 μm with velocities ranging from 4 to 11 m/s have been achieved. The frequency of operation is in the range of 50-100 kHz depending on the transverse operating mode and the length of the scalpel. The cutting ability of the micromachined scalpels has been successfully demonstrated on chicken tissue.

  10. Physical techniques for delivering microwave energy to tissues.

    PubMed Central

    Hand, J. W.

    1982-01-01

    Some of the physical aspects of delivering microwave energy to tissues have been discussed. Effective penetration of a few cm may be achieved with external applicators whilst small coaxial or cylindrical devices can induce localized heating in sites accessible to catheters or to direct invasion. To heat deep tissue sites in general, systems of greater complexity involving a number of applicators with particular phase relationships between them are required. The problems of thermometry in the presence of electromagnetic fields fall outside the scope of this article. Their solution, however, is no less important to the future of clinical hyperthermia than the development of heating techniques. Finally, it should be remembered that physiological parameters such as blood flow have appreciable effects in determining the efficacy of the physical techniques described above. PMID:6950781

  11. Microwave-Assisted Tissue Preparation for Rapid Fixation, Decalcification, Antigen Retrieval, Cryosectioning, and Immunostaining

    PubMed Central

    2016-01-01

    Microwave irradiation of tissue during fixation and subsequent histochemical staining procedures significantly reduces the time required for incubation in fixation and staining solutions. Minimizing the incubation time in fixative reduces disruption of tissue morphology, and reducing the incubation time in staining solution or antibody solution decreases nonspecific labeling. Reduction of incubation time in staining solution also decreases the level of background noise. Microwave-assisted tissue preparation is applicable for tissue fixation, decalcification of bone tissues, treatment of adipose tissues, antigen retrieval, and other special staining of tissues. Microwave-assisted tissue fixation and staining are useful tools for histological analyses. This review describes the protocols using microwave irradiation for several essential procedures in histochemical studies, and these techniques are applicable to other protocols for tissue fixation and immunostaining in the field of cell biology. PMID:27840640

  12. Optical properties of normal and thermally coagulated chicken liver tissue measured ex-vivo with diffuse reflectance

    NASA Astrophysics Data System (ADS)

    Hafeez-Ullah; Atif, M.; Firdous, S.; Mehmood, M. S.; Hamza, M. Y.; Imran, M.; Hussain, G.; Ikram, M.

    2011-02-01

    The purpose of the present study is to determine the optical properties of normal and thermally coagulated chicken liver at 720, 740, 770, 810, 825 and 840 nm wavelengths of laser irradiation. So, we were able to evaluate these optical properties (absorption and scattering coefficients) with ex-vivo study using Kubelka Munk Model (KMM) from the radial dependence of the diffuse reflectance with femtosecond pulsed laser in near IR region. These coefficients were significantly increased with coagulation. The penetration depths of the diffused light have been reported to a maximum value of 8.12 ± 0.36 mm in normal liver and 2.49 ± 0.17 mm in coagulated liver at 840 nm showing increasing behavior towards IR region. The Monte Carlo simulation was used to check the theoretical validation of measured optical properties of the tissue that showed a good match with our experimental results. We believe that these differences in optical properties will be helpful for the understanding arid optimal use of laser applications in medicine and differential diagnosis of tissues by using different optical methods. Especially for the investigation of biological tissue for photodynamic therapy (PDT), the knowledge of the specific optical properties and their thermo-induced changes is important.

  13. Radiofrequency and microwave ablation in combination with transarterial chemoembolization induce equivalent histopathologic coagulation necrosis in hepatocellular carcinoma patients bridged to liver transplantation

    PubMed Central

    Ginsburg, Michael; Ahmed, Osman; Doshi, Taral; Hart, John; Te, Helen; Van Ha, Thuong Gustav

    2016-01-01

    Background Bridging therapy plays an increasingly important role in the management of patients with hepatocellular carcinoma (HCC) awaiting liver transplantation (LT). Combination therapy with drug-eluting bead transarterial chemoembolization (DEB-TACE) and percutaneous thermal ablation, such as radiofrequency ablation (RFA) or microwave ablation (MWA), has shown success at prolonging survival and bridging patients to LT. However, few studies have evaluated the two combination therapy regimens head-to-head at a single institution, and fewer have compared histopathology. This retrospective study compares tumor coagulation on explanted livers in patients with HCC treated with DEB-TACE sequentially combined with RFA versus MWA. Methods From 2005 to 2015, 42 sequential patients underwent combination therapy prior to LT by Milan criteria, with 11 patients (11 tumors; mean, 2.9 cm; range, 1.8–4.3 cm) in the DEB-TACE/RFA cohort and 31 patients (40 tumors; mean, 2.4 cm; range, 1.1–5.4 cm) in the DEB-TACE/MWA cohort. The mean TACE procedures in the RFA and MWA cohorts were 1.3 (range, 1–2) and 1.3 (range, 1–3), respectively. The mean thermal ablations in the RFA and MWA cohorts were 1.2 (range, 1–2) and 1.3 (range, 1–3), respectively. Tumor coagulation was evaluated on explanted livers. Results Mean tumor coagulation in the RFA and MWA cohorts were 88.9% (range, 0–100%) and 90.5% (range, 30–100%), respectively (P=0.82). Rates of complete tumor coagulation in the RFA and MWA cohorts were 45% and 53%, respectively (P=0.74). No difference in tumor coagulation was found between the cohorts when separating tumors <3 cm (P=0.21) and >3 cm (P=0.09). Among all 51 tumors, the 36 in complete response (CR) on imaging at LT demonstrated mean tumor coagulation of 95.8%. No correlation was found between tumor coagulation and initial tumor size or time interval to LT. No tumor seeding was seen along the ablation tracts. Conclusions RFA and MWA in sequential combination

  14. Study of laser-induced thermoelastic deformation of native and coagulated ex-vivo bovine liver tissues for estimating their optical and thermomechanical properties.

    PubMed

    Soroushian, Behrouz; Whelan, William M; Kolios, Michael C

    2010-01-01

    Several studies have explored the potential of optoacoustic imaging for monitoring thermal therapies, yet the origin of the contrast in the images is not well understood. A technique is required to measure the changes in the optical and thermomechanical properties of tissues upon coagulation to better understand this contrast. An interferometric method is presented for measuring simultaneously the optical and thermomechanical properties of native and coagulated ex-vivo bovine tissue samples based on analysis of the surface displacement of irradiated samples. Surface displacements are measured after irradiation by short laser pulses at 750 nm. A 51% decrease in the optical attenuation depth is observed for coagulated liver samples compared to native samples. No significant differences in the Grüneisen coefficient are measured in the native and coagulated tissue samples. A mean value of 0.12 for the Grüneisen coefficient is measured for both native and coagulated liver tissues. The displacement profiles exhibit consistent differences between the two tissue types. To assess the changes in the sample mechanical properties, the experimental data also are compared to numerical solutions of the equation for thermoelastic deformation. The results demonstrate that differences in the tissue expansion dynamics arise from higher values of elastic modulus for coagulated liver samples compared to native ones.

  15. Tissue factor is induced by interleukin-33 in human endothelial cells: a new link between coagulation and inflammation

    PubMed Central

    Stojkovic, Stefan; Kaun, Christoph; Basilio, Jose; Rauscher, Sabine; Hell, Lena; Krychtiuk, Konstantin A.; Bonstingl, Cornelia; de Martin, Rainer; Gröger, Marion; Ay, Cihan; Holnthoner, Wolfgang; Eppel, Wolfgang; Neumayer, Christoph; Huk, Ihor; Huber, Kurt; Demyanets, Svitlana; Wojta, Johann

    2016-01-01

    Tissue factor (TF) is the primary trigger of coagulation. Elevated levels of TF are found in atherosclerotic plaques, and TF leads to thrombus formation when released upon plaque rupture. Interleukin (IL)-33 was previously shown to induce angiogenesis and inflammatory activation of endothelial cells (ECs). Here, we investigated the impact of IL-33 on TF in human ECs, as a possible new link between inflammation and coagulation. IL-33 induced TF mRNA and protein in human umbilical vein ECs and coronary artery ECs. IL-33-induced TF expression was ST2- and NF-κB-dependent, but IL-1-independent. IL-33 also increased cell surface TF activity in ECs and TF activity in ECs-derived microparticles. IL-33-treated ECs reduced coagulation time of whole blood and plasma but not of factor VII-deficient plasma. In human carotid atherosclerotic plaques (n = 57), TF mRNA positively correlated with IL-33 mRNA expression (r = 0.691, p < 0.001). In this tissue, IL-33 and TF protein was detected in ECs and smooth muscle cells by immunofluorescence. Furthermore, IL-33 and TF protein co-localized at the site of clot formation within microvessels in plaques of patients with symptomatic carotid stenosis. Through induction of TF in ECs, IL-33 could enhance their thrombotic capacity and thereby might impact on thrombus formation in the setting of atherosclerosis. PMID:27142573

  16. Infrared fiber optic temperature monitoring of biological tissues heated in a microwave oven

    NASA Astrophysics Data System (ADS)

    Belotserkovsky, Edward; Ashkenasy, Y.; Shenfeld, Ofer; Drizlikh, S.; Zur, Albert; Katzir, Abraham

    1993-05-01

    The heating of tissue by microwave radiation has attained a place of importance in various medical fields such as the treatment of malignancies, urinary retention and hypothermia. Accurate temperature measurements in these treated tissues is important for treatment planning and for the control of the heating process. It is also important to be able to measure spacial temperature distribution in the tissues because they are heated in a non uniform way by the microwave radiation. Fiber optic radiometry makes possible accurate temperature measurement in the presence of microwave radiation and does not require contact with the tissue. Using a IR silver halide fiber optic radiometric temperature sensor we obtained accurate temperature measurements of tissues heated by microwave, enabling us to control the heating process in all regions of the tissue. We also performed temperature mapping of the heated tissues and demonstrated the non-uniform temperature distributions in them.

  17. Dielectric permittivity of biological tissues in the microwave frequency range

    NASA Astrophysics Data System (ADS)

    Behari, J.; Alex, Z. C.; Zaidi, Zahid H.

    1994-09-01

    The accurate knowledge of complex dielectric behavior of biological tissues at microwave frequency is of great importance in the biomedical field for its diagnostic and therapeutic uses. This information is also essential for studying the mechanism underlying the absorption of electromagnetic energy and also the emission by tissues. In the present work, in vitro complex dielectric permittivity of liver and muscle were measured in the frequency range 0.6 GHz to 1.2 GHz using a network analyzer. An open ended coaxial cable method was used and the complex dielectric permittivity was measured from the actual terminal admittance of the sample. The system was calibrated with three standard samples. The measurements were conducted at room temperature. The calculated values of (Epsilon) ' varied from 53 to 48 for liver and from 49 to 46 for muscle. The corresponding (Epsilon) ' varied from 29 to 38 and 30 to 34 respectively. The relaxation frequency and degree of dispersion were also calculated and estimation of bound water content made in each case.

  18. The Role of Putative Phosphatidylserine-Interactive Residues of Tissue Factor on Its Coagulant Activity at the Cell Surface

    PubMed Central

    Ansari, Shabbir A.; Pendurthi, Usha R.; Sen, Prosenjit; Rao, L. Vijaya Mohan

    2016-01-01

    Exposure of phosphatidylserine (PS) on the outer leaflet of the cell membrane is thought to play a critical role in tissue factor (TF) decryption. Recent molecular dynamics simulation studies suggested that the TF ectodomain may directly interact with PS. To investigate the potential role of TF direct interaction with the cell surface phospholipids on basal TF activity and the enhanced TF activity following the decryption, one or all of the putative PS-interactive residues in the TF ectodomain were mutated and tested for their coagulant activity in cell systems. Out of the 9 selected TF mutants, five of them -TFS160A, TFS161A, TFS162A, TFK165A, and TFD180A- exhibited a similar TF coagulant activity to that of the wild-type TF. The specific activity of three mutants, TFK159A, TFS163A, and TFK166A, was reduced substantially. Mutation of the glycine residue at the position 164 markedly abrogated the TF coagulant activity, resulting in ~90% inhibition. Mutation of all nine lipid binding residues together did not further decrease the activity of TF compared to TFG164A. A similar fold increase in TF activity was observed in wild-type TF and all TF mutants following the treatment of THP-1 cells with either calcium ionomycin or HgCl2, two agents that are commonly used to decrypt TF. Overall, our data show that a few select TF residues that are implicated in interacting with PS contribute to the TF coagulant activity at the cell surface. However, our data also indicate that TF regions outside of the putative lipid binding region may also contribute to PS-dependent decryption of TF. PMID:27348126

  19. Automatic Multiple-Needle Surgical Planning of Robotic-Assisted Microwave Coagulation in Large Liver Tumor Therapy

    PubMed Central

    Liu, Shaoli; Xia, Zeyang; Liu, Jianhua; Xu, Jing; Ren, He; Lu, Tong; Yang, Xiangdong

    2016-01-01

    The “robotic-assisted liver tumor coagulation therapy” (RALTCT) system is a promising candidate for large liver tumor treatment in terms of accuracy and speed. A prerequisite for effective therapy is accurate surgical planning. However, it is difficult for the surgeon to perform surgical planning manually due to the difficulties associated with robot-assisted large liver tumor therapy. These main difficulties include the following aspects: (1) multiple needles are needed to destroy the entire tumor, (2) the insertion trajectories of the needles should avoid the ribs, blood vessels, and other tissues and organs in the abdominal cavity, (3) the placement of multiple needles should avoid interference with each other, (4) an inserted needle will cause some deformation of liver, which will result in changes in subsequently inserted needles’ operating environment, and (5) the multiple needle-insertion trajectories should be consistent with the needle-driven robot’s movement characteristics. Thus, an effective multiple-needle surgical planning procedure is needed. To overcome these problems, we present an automatic multiple-needle surgical planning of optimal insertion trajectories to the targets, based on a mathematical description of all relevant structure surfaces. The method determines the analytical expression of boundaries of every needle “collision-free reachable workspace” (CFRW), which are the feasible insertion zones based on several constraints. Then, the optimal needle insertion trajectory within the optimization criteria will be chosen in the needle CFRW automatically. Also, the results can be visualized with our navigation system. In the simulation experiment, three needle-insertion trajectories were obtained successfully. In the in vitro experiment, the robot successfully achieved insertion of multiple needles. The proposed automatic multiple-needle surgical planning can improve the efficiency and safety of robot-assisted large liver tumor

  20. EXTRACTION OF ORGANIC CONTAMINANTS FROM MARINE SEDIMENTS AND TISSUES USING MICROWAVE ENERGY

    EPA Science Inventory

    In this study, we compared microwave solvent extraction (MSE) to conventional methods for extracting organic contaminants from marine sediments and tissues with high and varying moisture content. The organic contaminants measured were polychlorinated biphenyl (PCB) congeners, chl...

  1. A comparative study of tissue factor and kaolin on blood coagulation assays using rotational thromboelastometry and thromboelastography.

    PubMed

    Peng, Henry T; Grodecki, Richard; Rizoli, Sandro; Shek, Pang N

    2016-01-01

    Rotational thromboelastometry (ROTEM) and thromboelastography (TEG) have been increasingly used to diagnose acute coagulopathy and guide blood transfusion. The tests are routinely performed using different triggering activators such as tissue factor and kaolin, which activate different pathways yielding different results. To optimize the global blood coagulation assays using ROTEM and TEG, we conducted a comparative study on the activation methods employing tissue factor and kaolin at different concentrations as well as standard reagents as recommended by the manufacturer of each device. Key parameter values were obtained at various assay conditions to evaluate and compare coagulation and fibrinolysis profiles of citrated whole blood collected from healthy volunteers. It was found that tissue factor reduced ROTEM clotting time and TEG R, and increased ROTEM clot formation time and TEG K in a concentration-dependent manner. In addition, tissue factor affected ROTEM alpha angle, and maximum clot firmness, especially in the absence of kaolin activation, whereas both ROTEM and TEG clot lysis (LI30, CL30, and LY30) remained unaffected. Moreover, kaolin reduced ROTEM clotting time and TEG R and K, but to a lesser extent than tissue factor, in-tem and ex-tem. Correlations in all corresponding parameters between ROTEM and TEG were observed, when the same activators were used in the assays compared with lesser correlations between standard kaolin TEG and ROTEM (INTEM/EXTEM). The two types of viscoelastic point-of-care devices provide different results, depending on the triggering reagent used to perform the assay. Optimal assay condition was obtained to reduce assay time and improve assay accuracy.

  2. Optical properties measurement of laser coagulated tissues with double integrating sphere and inverse Monte Carlo technique in the wavelength range from 350 to 2100 nm

    NASA Astrophysics Data System (ADS)

    Honda, Norihiro; Nanjo, Takuya; Ishii, Katsunori; Awazu, Kunio

    2012-03-01

    In laser medicine, the accurate knowledge about the optical properties (absorption coefficient; μa, scattering coefficient; μs, anisotropy factor; g) of laser irradiated tissues is important for the prediction of light propagation in tissues, since the efficacy of laser treatment depends on the photon propagation within the irradiated tissues. Thus, it is likely that the optical properties of tissues at near-ultraviolet, visible and near-infrared wavelengths will be more important due to more biomedical applications of lasers will be developed. For improvement of the laser induced thermotherapy, the optical property change during laser treatment should be considered in the wide wavelength range. For estimation of the optical properties of the biological tissues, the optical properties measurement system with a double integrating sphere setup and an inverse Monte Carlo technique was developed. The optical properties of chicken muscle tissue were measured in the native state and after laser coagulation using the optical properties measurement system in the wavelength range from 350 to 2100 nm. A CO2 laser was used for laser coagulation. After laser coagulation, the reduced scattering coefficient of the tissue increased. And, the optical penetration depth decreased. For improvement of the treatment depth during laser coagulation, a quantitative procedure using the treated tissue optical properties for determination of the irradiation power density following light penetration decrease might be important in clinic.

  3. Silver halide fiber optic radiometry for temperature monitoring and control of tissues heated by microwave

    NASA Astrophysics Data System (ADS)

    Shenfeld, Ofer; Belotserkovsky, Edward; Goldwasser, Benad; Zur, Albert; Katzir, Abraham

    1993-02-01

    The heating of tissue by microwave radiation has attained a place of importance in various medical fields, such as the treatment of malignancies, urinary retention, and hypothermia. Accurate temperature measurements in these treated tissues is important for treatment planning and for the control of the heating process. It is also important to be able to measure spacial temperature distribution in the tissues because they are heated in a nonuniform way by the microwave radiation. Conventional temperature sensors used today are inaccurate in the presence of microwave radiation and require contact with the heated tissue. Fiber optic radiometry makes it possible to measure temperatures accurately in the presence of microwave radiation and does not require contact with the tissue. Accurate temperature measurements of tissues heated by microwave was obtained using a silver halide optic radiometer, enabling control of the heating process in other regions of the tissue samples. Temperature mappings of the heated tissues were performed and the nonuniform temperature distributions in these tissues was demonstrated.

  4. Tissue Factor in Dermatitis Herpetiformis and Bullous Pemphigoid: Link between Immune and Coagulation System in Subepidermal Autoimmune Bullous Diseases

    PubMed Central

    Zebrowska, Agnieszka; Wagrowska-Danilewicz, Malgorzata; Danilewicz, Marian; Wieczfinska, Joanna; Pniewska, Ewa; Zebrowski, Michal; Waszczykowska, Elzbieta; Wozniacka, Anna; Eusebio, Makandjou-Ola; Pietruczuk, Miroslawa; Pawliczak, Rafal

    2015-01-01

    Dermatitis herpetiformis (DH) and bullous pemphigoid (BP) are skin diseases associated with eosinophilic and neutrophilic infiltrations. Although chemokines are critical for the selective accumulation and activation of various leukocyte subsets in the inflammatory process, there are few findings concerning inflammatory cells and production of coagulation factors in blistering diseases. Skin biopsies were taken from 14 patients with DH, 27 with BP, and 20 control subjects. The localization and expression of tissue factor (TF) in skin lesions and perilesional skin were studied by immunohistochemistry and confirmed by Western Blot. Moreover the plasma concentrations of TF were measured by immunoassays. D dimers, fibrinogen, and selected coagulation parameters were measured by routine methods. Expression of TF in the epidermis and in inflammatory influxed cells in dermis was detected in skin biopsies from BP patients. Examined TF expression was detected in perilesional skin of all BP patients too. The expression of TF was not observed in biopsies from healthy people and DH patients. The findings of the study show an increased expression of tissue factor in the lesional and perilesional skin of patients with bullous pemphigoid. The difference in chemokine pattern expression and variations in the cellular infiltration in BP and DH cause variable expression of TF. PMID:27057091

  5. Microwave dielectric measurements and tissue characteristics of the human brain: potential in localizing intracranial tissues.

    PubMed

    Axer, Hubertus; Grässel, David; Steinhauer, Matthias; Stöhr, Peter; John, Andreas; Coenen, Volker A; Jansen, Rolf H; von Keyserlingk, Diedrich Graf

    2002-05-21

    This study describes the measurements of dielectric properties in the microwave range to differentiate various human central nervous structures. Using a vector network analyser transmission and reflection coefficients were measured from 500 MHz to 18 GHz in four human formalin fixed human brains. The positions of the electrodes were marked, and the tissue was histologically stained to visualize the myelo- and the cytoarchitecture as well as the nerve fibre orientation at the electrodes. The profiles of the transmission coefficients showed a characteristic minimum peak. In order to describe this peak, a mathematical function was fitted. Parameters derived from digital image processing were used to characterize the myelo- and cytoarchitecure of the tissue at the electrodes. A multiple regression model, with the frequency at the transmission peak minimum as a dependent variable and two tissue characteristics at the two electrodes as independent variables, showed a multiple regression coefficient of 0.765. A neural network model was able to estimate the frequency at the transmission peak minimum from the tissue characteristics at the electrode. The measurements of dielectric properties are well suited to differentiate distinct intracerebral structures. The method could be used for online monitoring of the needle's position during a stereotactic intervention in neurosurgery.

  6. Platelet-Derived Short-Chain Polyphosphates Enhance the Inactivation of Tissue Factor Pathway Inhibitor by Activated Coagulation Factor XI

    PubMed Central

    Puy, Cristina; Tucker, Erik I.; Ivanov, Ivan S.; Gailani, David; Smith, Stephanie A.; Morrissey, James H.; Gruber, András; McCarty, Owen J. T.

    2016-01-01

    Introduction Factor (F) XI supports both normal human hemostasis and pathological thrombosis. Activated FXI (FXIa) promotes thrombin generation by enzymatic activation of FXI, FIX, FX, and FV, and inactivation of alpha tissue factor pathway inhibitor (TFPIα), in vitro. Some of these reactions are now known to be enhanced by short-chain polyphosphates (SCP) derived from activated platelets. These SCPs act as a cofactor for the activation of FXI and FV by thrombin and FXIa, respectively. Since SCPs have been shown to inhibit the anticoagulant function of TFPIα, we herein investigated whether SCPs could serve as cofactors for the proteolytic inactivation of TFPIα by FXIa, further promoting the efficiency of the extrinsic pathway of coagulation to generate thrombin. Methods and Results Purified soluble SCP was prepared by size-fractionation of sodium polyphosphate. TFPIα proteolysis was analyzed by western blot. TFPIα activity was measured as inhibition of FX activation and activity in coagulation and chromogenic assays. SCPs significantly accelerated the rate of inactivation of TFPIα by FXIa in both purified systems and in recalcified plasma. Moreover, platelet-derived SCP accelerated the rate of inactivation of platelet-derived TFPIα by FXIa. TFPIα activity was not affected by SCP in recalcified FXI-depleted plasma. Conclusions Our data suggest that SCP is a cofactor for TFPIα inactivation by FXIa, thus, expanding the range of hemostatic FXIa substrates that may be affected by the cofactor functions of platelet-derived SCP. PMID:27764259

  7. Positive Feedback Loops for Factor V and Factor VII Activation Supply Sensitivity to Local Surface Tissue Factor Density During Blood Coagulation

    PubMed Central

    Balandina, A.N.; Shibeko, A.M.; Kireev, D.A.; Novikova, A.A.; Shmirev, I.I.; Panteleev, M.A.; Ataullakhanov, F.I.

    2011-01-01

    Blood coagulation is triggered not only by surface tissue factor (TF) density but also by surface TF distribution. We investigated recognition of surface TF distribution patterns during blood coagulation and identified the underlying molecular mechanisms. For these investigations, we employed 1), an in vitro reaction-diffusion experimental model of coagulation; and 2), numerical simulations using a mathematical model of coagulation in a three-dimensional space. When TF was uniformly immobilized over the activating surface, the clotting initiation time in normal plasma increased from 4 min to >120 min, with a decrease in TF density from 100 to 0.7 pmol/m2. In contrast, surface-immobilized fibroblasts initiated clotting within 3–7 min, independently of fibroblast quantity and despite a change in average surface TF density from 0.5 to 130 pmol/m2. Experiments using factor V-, VII-, and VIII-deficient plasma and computer simulations demonstrated that different responses to these two TF distributions are caused by two positive feedback loops in the blood coagulation network: activation of the TF–VII complex by factor Xa, and activation of factor V by thrombin. This finding suggests a new role for these reactions: to supply sensitivity to local TF density during blood coagulation. PMID:22004734

  8. A simple method for determining the coagulation threshold temperature of transparent tissue-mimicking thermal therapy gel phantoms: Validated by magnetic resonance imaging thermometry

    PubMed Central

    Brodin, N. Patrik; Partanen, Ari; Asp, Patrik; Branch, Craig A.; Guha, Chandan; Tomé, Wolfgang A.

    2016-01-01

    Purpose: Tissue-mimicking thermal therapy phantoms that coagulate at specific temperatures are valuable tools for developing and evaluating treatment strategies related to thermal therapy. Here, the authors propose a simple and efficient method for determining the coagulation threshold temperature of transparent thermal therapy gel phantoms. Methods: The authors used a previously published gel phantom recipe with 2% (w/v) of bovine serum albumin as the temperature-sensitive protein. Using the programmable heating settings of a polymerase chain reaction (PCR) machine, the authors heated 50 μl gel samples to various temperatures for 3 min and then imaged them using the BioRad Gel Doc system to determine the coagulation temperature using an opacity quantification method. The estimated coagulation temperatures were then validated for gel phantoms prepared with different pH levels using high-intensity focused ultrasound (HIFU) heating and magnetic resonance imaging (MRI) thermometry methods on a clinical MR-HIFU system. Results: The PCR heating method produced consistent and reproducible coagulation of gel samples in precise correlation with the set incubation temperatures. The resulting coagulation threshold temperatures for gel phantoms of varying pH levels were found to be 44.1 ± 0.1, 53.4 ± 0.9, and 60.3 ± 0.9 °C for pH levels of 4.25, 4.50, and 4.75, respectively. This corresponded well with the coagulation threshold temperatures determined by MR-thermometry, with coagulation defined as a 95% decrease in T2 relaxation time, which were estimated at 53.6 ± 1.9 and 62.9 ± 2.4 °C for a pH of 4.50 and 4.75, respectively. Conclusions: The opacity quantification method provides a fast and reproducible estimate of the coagulation threshold temperature of transparent temperature-sensitive gel phantoms. The temperatures determined using this method were well within the range of temperatures estimated using MR-thermometry. Due to the specific heating capabilities

  9. [Physical model of the plant tissue response to exposure to the microwave electromagnetic field].

    PubMed

    Kalinin, L G; Boshkova, I L

    2003-01-01

    A hypothesis was suggested to explain the effect of biostimulation of seeds exposed to microwave electromagnetic field. It was shown that the assumption on the determining influence of the microwave field on the transport properties of the conducting system of a plant satisfactorily explains the phenomena observed in germinating seeds and growing plants. A physical model of the response of a plant cell to a microwave field is presented, which served as a basis for the method of calculating the maximum possible time of exposure of plant tissue.

  10. Moojenactivase, a novel pro-coagulant PIIId metalloprotease isolated from Bothrops moojeni snake venom, activates coagulation factors II and X and induces tissue factor up-regulation in leukocytes.

    PubMed

    Sartim, Marco A; Costa, Tassia R; Laure, Helen J; Espíndola, Milena S; Frantz, Fabiani G; Sorgi, Carlos A; Cintra, Adélia C O; Arantes, Eliane C; Faccioli, Lucia H; Rosa, José C; Sampaio, Suely V

    2016-05-01

    Coagulopathies following snakebite are triggered by pro-coagulant venom toxins, in which metalloproteases play a major role in envenomation-induced coagulation disorders by acting on coagulation cascade, platelet function and fibrinolysis. Considering this relevance, here we describe the isolation and biochemical characterization of moojenactivase (MooA), a metalloprotease from Bothrops moojeni snake venom, and investigate its involvement in hemostasis in vitro. MooA is a glycoprotein of 85,746.22 Da, member of the PIIId group of snake venom metalloproteases, composed of three linked disulfide-bonded chains: an N-glycosylated heavy chain, and two light chains. The venom protease induced human plasma clotting in vitro by activating on both blood coagulation factors II (prothrombin) and X, which in turn generated α-thrombin and factor Xa, respectively. Additionally, MooA induced expression of tissue factor (TF) on the membrane surface of peripheral blood mononuclear cells (PBMC), which led these cells to adopt pro-coagulant characteristics. MooA was also shown to be involved with production of the inflammatory mediators TNF-α, IL-8 and MCP-1, suggesting an association between MooA pro-inflammatory stimulation of PBMC and TF up-regulation. We also observed aggregation of washed platelets when in presence of MooA; however, the protease had no effect on fibrinolysis. Our findings show that MooA is a novel hemostatically active metalloprotease, which may lead to the development of coagulopathies during B. moojeni envenomation. Moreover, the metalloprotease may contribute to the development of new diagnostic tools and pharmacological approaches applied to hemostatic disorders.

  11. Histology-directed microwave assisted enzymatic protein digestion for MALDI MS analysis of mammalian tissue.

    PubMed

    Taverna, Domenico; Norris, Jeremy L; Caprioli, Richard M

    2015-01-06

    This study presents on-tissue proteolytic digestion using a microwave irradiation and peptide extraction method for in situ analysis of proteins from spatially defined regions of a tissue section. The methodology utilizes hydrogel discs (1 mm diameter) embedded with trypsin solution. The enzyme-laced hydrogel discs are applied to a tissue section, directing enzymatic digestion to a spatially confined area of the tissue. By applying microwave radiation, protein digestion is performed in 2 min on-tissue, and the extracted peptides are then analyzed by matrix assisted laser desorption/ionization mass spectrometry (MALDI MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS). The reliability and reproducibility of the microwave assisted hydrogel mediated on-tissue digestion is demonstrated by the comparison with other on-tissue digestion strategies, including comparisons with conventional heating and in-solution digestion. LC-MS/MS data were evaluated considering the number of identified proteins as well as the number of protein groups and distinct peptides. The results of this study demonstrate that rapid and reliable protein digestion can be performed on a single thin tissue section while preserving the relationship between the molecular information obtained and the tissue architecture, and the resulting peptides can be extracted in sufficient abundance to permit analysis using LC-MS/MS. This approach will be most useful for samples that have limited availability but are needed for multiple analyses, especially for the correlation of proteomics data with histology and immunohistochemistry.

  12. Histology-Directed Microwave Assisted Enzymatic Protein Digestion for MALDI MS Analysis of Mammalian Tissue

    PubMed Central

    2015-01-01

    This study presents on-tissue proteolytic digestion using a microwave irradiation and peptide extraction method for in situ analysis of proteins from spatially defined regions of a tissue section. The methodology utilizes hydrogel discs (1 mm diameter) embedded with trypsin solution. The enzyme-laced hydrogel discs are applied to a tissue section, directing enzymatic digestion to a spatially confined area of the tissue. By applying microwave radiation, protein digestion is performed in 2 min on-tissue, and the extracted peptides are then analyzed by matrix assisted laser desorption/ionization mass spectrometry (MALDI MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS). The reliability and reproducibility of the microwave assisted hydrogel mediated on-tissue digestion is demonstrated by the comparison with other on-tissue digestion strategies, including comparisons with conventional heating and in-solution digestion. LC-MS/MS data were evaluated considering the number of identified proteins as well as the number of protein groups and distinct peptides. The results of this study demonstrate that rapid and reliable protein digestion can be performed on a single thin tissue section while preserving the relationship between the molecular information obtained and the tissue architecture, and the resulting peptides can be extracted in sufficient abundance to permit analysis using LC-MS/MS. This approach will be most useful for samples that have limited availability but are needed for multiple analyses, especially for the correlation of proteomics data with histology and immunohistochemistry. PMID:25427280

  13. Validation of microwave radiometry for measuring the internal temperature profile of human tissue

    NASA Astrophysics Data System (ADS)

    Levick, A.; Land, D.; Hand, J.

    2011-06-01

    A phantom target with a known linear temperature gradient has been developed for validating microwave radiometry for measuring internal temperature profiles within human tissue. The purpose of the phantom target is to simulate the temperature gradient found within the surface layers of a baby's brain during hypothermal neuroprotection therapy, in which the outer surface of the phantom represents the skin surface and the inner surface the brain core. The target comprises a volume of phantom tissue material with similar dielectric properties to high water-content human tissue, contained between two copper plates at known temperatures. The antenna of a microwave radiometer is in contact with one surface of the phantom material. We have measured the microwave temperature of the phantom with microwave radiometry in a frequency band of 3.0-3.5 GHz. Our microwave temperature measurements have small 0.05 °C (type A) uncertainties associated with random effects and provide temperatures consistent with values determined using theoretical models of the antenna-target system within uncertainties. The measurements are in good agreement with the major signal contribution being formed over a near plane-wave response within the material with a much smaller contribution from close to the antenna face.

  14. Microwave-stimulated formaldehyde fixation of experimental renal biopsy tissues: computerised morphometric analysis of distortion artefacts.

    PubMed

    Looi, Lai-Meng; Loh, Kum-Chee

    2005-06-01

    Although microwave irradiation has been used in the histopathology laboratory for several years, there has been minimal published experimental data on its effects on the technical and staining quality of histological sections. Furthermore, it has not been clear whether the advantages gained in reduction of fixation and staining duration has been at the expense of increasing architectural distortion to the tissues. We report here our experience with computerised morphometric analysis to investigate glomerular artifacts caused by microwave-stimulated fixation of renal tissues. 39 rat and 33 human autopsy kidney samples were subjected to (1) fixation in neutral buffered formaldehyde (control), (2) microwave-stimulated fixation followed by neutral buffered formaldehyde, and (3) neutral buffered formaldehyde followed by microwave irradiation. In addition, the effect of post-fixation in 70% ethanol was also investigated. Microwave irradiation was delivered through a dedicated laboratory microwave oven at 80% power and at 55 degrees C for 3 minutes. The different fixation methods were compared with regards to shrinkage (distortion) to glomerular structures (glomeruli and Bowman's spaces) on H and E sections, as determined by morphometric image analysis using a temporary assembled-system consisting of a trinocular microscope, a digital video camera and personal computer. A FlashPoint VGA 3.3 film-grabber card was used to capture images for morphometric analysis by using a Scion Image program. Morphometric analysis of glomerular structures showed that microwaves caused more shrinkage to the area bounded by the Bowman's capsule than the glomerulus proper, but post-fixation with ethanol reduced this shrinkage. These findings have implications on the logistics of tissue preparation of renal biopsies in clinical practice.

  15. [Histologic tissue processing in an automated microwave histoprocessor].

    PubMed

    Zubkova, T V; Makarov, V L; Nemykin, V I; Tarnopol'skaia, O V; Nepomniashchaia, E M; Marmarova, T Iu

    1999-01-01

    A new vacuum histoprocessor has been tested as well as new more effective protocols to work with this processor. The device allows histoprocessing of 50 samples simultaneously of surgery, biopsy or autopsy material during 1-1.5 h. Apart from the standard protocols, new protocols with a much lower (5-10 times) expenditure of the chemicals can be implemented due to combination of microwaves and vacuum. Each protocol was tested repeatedly (20 and more times) with stable good quality of microscopic image.

  16. Dual-mode antenna array for microwave heating and noninvasive thermometry of superficial tissue disease

    NASA Astrophysics Data System (ADS)

    Stauffer, Paul R.; Jacobsen, Svein; Rossetto, Francesca; Diederich, Chris J.; Neuman, Daniel

    1999-05-01

    Hyperthermia therapy of superficial skin disease has proven clinically useful, but current heating equipment is clumsy and technically inadequate for many patients. The present effort describes a dual purpose multielement conformal array microwave applicator that is fabricated from flexible printed circuit board (PCB) material to facilitate heating of large surface areas overlying contoured anatomy. Preliminary studies document the feasibility of combining concentric spiral microstrip antennas within multilayer PCB material in order to achieve tissue heating simultaneously with non-invasive thermometry by radiometric sensing of blackbody radiation from the target tissue under the applicator. Results demonstrate that superficial tissue regions may be heated uniformly above 50% of SARmax out to the periphery of 915 MHz conformal array applicators made from arrays of Dual Concentric Conductor apertures. Finally the data clearly demonstrate that separate complimentary antenna structures may be combined together in thin and lightweight conformal arrays to provide heating simultaneously with microwave radiometry based temperature monitoring of superficial tissue.

  17. Changes in backscatter of liver tissue due to thermal coagulation induced by focused ultrasound.

    PubMed

    Shishitani, Takashi; Matsuzawa, Ryo; Yoshizawa, Shin; Umemura, Shin-ichiro

    2013-08-01

    Ultrasonic imaging has advantages in its self-consistency in guiding and monitoring ultrasonic treatment such as high-intensity focused ultrasound (HIFU) treatment. Changes in ultrasonic backscatter of tissues due to HIFU treatment have been observed, but their mechanism is still under discussion. In this paper, ultrasonic backscatter of excised and degassed porcine liver tissue was observed before and after HIFU exposure using a diagnostic scanner, and its acoustic impedance was mapped using an ultrasonic microscope. The histology of its pathological specimen was also observed using an optical microscope. The observed decrease in backscatter intensity due to HIFU exposure was consistent with a spatial Fourier analysis of the histology, which also showed changes due to the exposure. The observed increase in acoustic impedance due to the exposure was also consistent with the histological change assuming that the increase was primarily caused by the increase in the concentration of hepatic cells.

  18. Microwave irradiation of human brain tissue: production of microscopic slides within one day.

    PubMed Central

    Boon, M E; Marani, E; Adriolo, P J; Steffelaar, J W; Bots, G T; Kok, L P

    1988-01-01

    A three step method using microwave irradiation enabled microscopic slides of human brain tissue to be obtained within one working day: steps 1 and 2 hardened and solidified brain tissue; step 3 completed formalin fixation. The efficacy and precision of the method was compared with slides of conventionally processed brain tissue that had been fixed in formalin for six weeks. The microscopic quality of the sections was excellent with good presentation of brain tissue and equalled that of conventionally processed slides. Images Fig 1 Fig 2 Fig 3 PMID:3290268

  19. Tissue structure of rat brain after microwave irradiation using maximum magnetic field component.

    PubMed

    Ikarashi, Y; Okada, M; Maruyama, Y

    1986-05-14

    A novel microwave instrument has recently been designed by New Japan Radio Co. Ltd., to provide more homogeneous distribution of the rapidly deposited heat in the rodent brain. Being the first commercial unit which concentrates the maximum magnetic field component of irradiation, rather than the usual electric field, it provides complete enzymatic inactivation in a typical rat brain when a power of 9 kW (90% of maximum) is applied for 0.80 s at the standard operating frequency of 2450 MHz. Tissue structural integrity was investigated in animals sacrificed by this approach or by the usual decapitation to see if any tissue disruption or pressure-induced spreading, a major problem with other microwave devices, might also be of concern for this new unit. Histological examination of tissue samples employed both light and electron microscopy. Using Luxol Fast Blue in the light microscopy, the microwave irradiated tissues exhibited a decreased affinity for the staining agent, an appearance of slight vacuoles, and the disappearance of fine fibrils in the parenchyma. However, the interfacial areas between distinct brain regions remained well preserved. Electron microscopic observation indicated that microwave irradiated tissue caused protein denaturation accompanied by the aggregation of nuclear chromatin, the disappearance of Nissl bodies, ribosomes and neurofilaments, and noticeably irregular myelin sheaths. However, the essential structure of nerve cell membranes and synaptic membranes were maintained, and synaptic vesicles were clearly defined. These results indicated that the rapid heating of brain tissue with maximal magnetic field concentration of the irradiation does not result in significant tissue disruption, pressure-induced spreading or cell breakdown.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Breast tissue phantoms to assist compression study for cancer detection using microwave radiometry.

    PubMed

    Akki, Rachana S; Arunachalam, Kavitha

    2014-01-01

    Microwave radiometry is a passive imaging modality proposed for breast cancer detection without the need for ionizing radiation. Detection of breast tumor using radiometry is challenging as the intensity of thermal radiation received by the antenna is influenced by tumor stage, location, physiological conditions and the imaging setup. The controllable parameters for setting up a good imaging modality for early detection of breast cancer are ambient temperature (Ta), convection cooling of tissue surface (h), and tissue compression (c). Amongst these parameters tissue compression plays an important role since reducing the breast thickness increases visibility. In this work, fabrication of hydrogel breast tissue phantoms with varying concentrations of polyvinyl alcohol (PVAL) is carried out to mimic breast fat and glandular tissue properties for compression study. The phantoms were subjected to compression to investigate the mechanical properties for varying PVAL concentrations. A 3D numerical model was developed for phantom tissue compression simulations. Simulated tissue compression results were compared with phantom measurements for model validation.

  1. Hemophilia as a defect of the tissue factor pathway of blood coagulation: Effect of factors VIII and IX on factor X activation in a continuous-flow reactor

    SciTech Connect

    Repke, D.; Gemmell, C.H.; Guha, A.; Turitto, V.T.; Nemerson, Y. ); Broze, G.J. Jr. )

    1990-10-01

    The effect of factors VIII and IX on the ability of the tissue factor-factor VIIa complex to activate factor X was studied in a continuous-flow tubular enzyme reactor. Tissue factor immobilized in a phospholipid bilayer on the inner surface of the tube was exposed to a perfusate containing factors VIIa, VIII, IX, and X flowing at a wall shear rate of 57, 300, or 1130 sec{sup {minus}1}. The addition of factors VIII and IX at their respective plasma concentrations resulted in a further 2{endash}-to 3{endash}fold increase. The direct activation of factor X by tissue factor-factor VIIa could be virtually eliminated by the lipoprotein-associated coagulation inhibitor. These results suggest that the tissue factor pathway, mediated through factors VIII and IX, produces significant levels of factor Xa even in the presence of an inhibitor of the tissue factor-factor VIIa complex; moreover, the activation is dependent on local shear conditions. These findings are consistent both with a model of blood coagulation in which initiation of the system results from tissue factor and with the bleeding observed in hemophilia.

  2. Coagulation and sepsis.

    PubMed

    Levi, Marcel; van der Poll, Tom

    2017-01-01

    Severe sepsis is almost invariably associated with systemic activation of coagulation. There is ample evidence that demonstrates a wide-ranging cross-talk between hemostasis and inflammation, which is probably implicated in the pathogenesis of organ dysfunction in patients with sepsis. Inflammation not only leads to initiation and propagation of coagulation activity, but coagulation also markedly influences inflammation. Molecular mechanisms that play a role in inflammation-induced effects on coagulation have been recognized in much detail. Pro-inflammatory cells and cyto- and chemokines can activate the coagulation system and downregulate crucial physiological anticoagulant mechanisms. Initiation of coagulation activation and consequent thrombin generation is caused by expression of tissue factor on activated monocytes and endothelial cells and is ineffectually offset by tissue factor pathway inhibitor. At the same time, endothelial-associated anticoagulant pathways, in particular the protein C system, is impaired by pro-inflammatory cytokines. Also, fibrin removal is severely obstructed by inactivation of the endogenous fibrinolytic system, mainly as a result of upregulation of its principal inhibitor, plasminogen activator inhibitor type 1 (PAI-1). Increased fibrin generation and impaired break down lead to deposition of (micro)vascular clots, which may contribute to tissue ischemia and ensuing organ dysfunction. The foundation of the management of coagulation in sepsis is the explicit and thorough treatment of the underlying disorder by antibiotic treatment and source control measures. Adjunctive strategies focused at the impairment of coagulation, including anticoagulants and restoration of physiological anticoagulant mechanisms, may supposedly be indicated and have been found advantageous in experimental and initial clinical trials.

  3. Minimum wound size for clotting: flowing blood coagulates on a single collagen fiber presenting tissue factor and von Willebrand factor.

    PubMed

    Zhu, Shu; Tomaiuolo, Maurizio; Diamond, Scott L

    2016-08-08

    It is unknown if a lower size limit exists for human blood coagulation under flow over physiological vessel wall triggers as small as a single collagen fiber. Prior determinations of the smallest sized surface stimuli necessary for clotting of human blood, defined as the patch size threshold, have not deployed whole blood, hemodynamic flow, and platelet adhesive stimuli. For whole blood perfused in microfluidic devices, we report that steady venous flow (wall shear rate, 100 s(-1)) was sufficient to drive platelet deposition on 20 micron long zones of collagen fibers or on a single fiber. With tissue factor (TF)-coated collagen, flowing blood generated robust platelet deposits, platelet-localized thrombin, and fibrin on a single collagen fiber, thus demonstrating the absence of a physiological patch size threshold under venous flow. In contrast, at arterial wall shear rate (1000 s(-1)) with TF present, essentially no platelet or fibrin deposition occurred on 20 micron collagen zones or on a single collagen fiber, demonstrating a patch threshold, which was overcome by pre-coating the collagen with von Willebrand factor (vWF). For venous flows, human blood can clot on one of the smallest biological units of a single collagen fiber presenting TF. For arterial flows, vWF together with TF allows human blood to generate thrombin and fibrin on a patch stimulus as limited as a single collagen fiber. vWF-dependent platelet adhesion represents a particle-based sensing mechanism of micron-scale stimuli that then allows amplification of the molecular components of TF-driven thrombin and fibrin production under arterial flow.

  4. Microwave Radar Imaging of Heterogeneous Breast Tissue Integrating A Priori Information

    PubMed Central

    Kelly, Thomas N.; Sarafianou, Mantalena; Craddock, Ian J.

    2014-01-01

    Conventional radar-based image reconstruction techniques fail when they are applied to heterogeneous breast tissue, since the underlying in-breast relative permittivity is unknown or assumed to be constant. This results in a systematic error during the process of image formation. A recent trend in microwave biomedical imaging is to extract the relative permittivity from the object under test to improve the image reconstruction quality and thereby to enhance the diagnostic assessment. In this paper, we present a novel radar-based methodology for microwave breast cancer detection in heterogeneous breast tissue integrating a 3D map of relative permittivity as a priori information. This leads to a novel image reconstruction formulation where the delay-and-sum focusing takes place in time rather than range domain. Results are shown for a heterogeneous dense (class-4) and a scattered fibroglandular (class-2) numerical breast phantom using Bristol's 31-element array configuration. PMID:25435861

  5. Microwave oven-based technique for immunofluorescent staining of paraffin-embedded tissues.

    PubMed

    Long, Delwin J; Buggs, Colleen

    2008-02-01

    Immunohistochemical analysis of formalin-fixed paraffin-embedded tissues can be challenging due to potential modifications of protein structure by exposure to formalin. Heat-induced antigen retrieval techniques can reverse reactions between formalin and proteins that block antibody recognition. Interactions between antibodies and antigens are further enhanced by microwave irradiation, which has simplified immunohistochemical staining protocols. In this report, we modify a technique for antigen retrieval and immunofluorescent staining of formalin-fixed paraffin-embedded tissues by showing that it works well with several antibodies and buffers. This microwave-assisted method for antigen retrieval and immunofluorescent staining eliminates the need for blocking reagents and extended washes, which greatly simplifies the protocol allowing one to complete the analysis in less than 3 h.

  6. Dual-sided electrosurgery handpiece for simultaneous tissue cutting and coagulation: first report on a conceptual design validated by an animal experiment

    PubMed Central

    Tawfik, Hatem A; Fouad, Yousef A; Hafez, Rashad

    2015-01-01

    Objective To introduce and evaluate the safety of a novel dual-sided electrosurgery handpiece design for simultaneous tissue cutting and coagulation. Methods We designed a prototype double-sided handpiece allowing automatic switching between two electrodes with a simple handpiece flip. The concept of the system as a surgical instrument was assessed by an animal experiment. Results The skin of 15 Wistar albino white rats could be successfully incised and coagulated using both ends of the handpiece, thereby confirming the prospects and clinical applications of the system. Conclusion The dual-sided electrosurgery handpiece is a simple and safe alternative to the traditional electrosurgery pencil, allowing the simultaneous use of two electrodes without the hassle of frequent electrode replacement. PMID:26316827

  7. Improving heating uniformity of pathological tissue specimens inside a domestic microwave oven.

    PubMed

    Hassan, Osama A; Kandil, Ahmed H; El Bialy, Ahmed M; Hassaballa, Iman A

    2013-01-01

    A 3D coupled electromagnetic thermal model was developed using COMSOL 4.0 to predict the electromagnetic field distribution and temperature profile in pathological tissue samples immersed in a reagent inside the oven cavity. The effect of the volume of reagent on the mean heating rate and heating uniformity within the tissue sample was investigated. Also, the effect of using a water load, as a method of temperature control, is emphasized. A well insulated K type thermocouple connected to a PC is used for model validation. Good agreement is found between experimental and simulated temperature profiles. Results show that as the volume of reagent increases, the mean heating rate decreases and temperature homogeneity increases. Also, it is possible to minimize overshooting temperature values inside the tissue sample and enhance tissue uniformity by about 27% using 100 ml of water load and 42.26% using 150 ml. Domestic microwave oven is a low cost economical tool that can speed up tissue processing steps. Achieving uniform heating inside the microwave oven is the key factor for improving workflow inside pathological labs and maintaining tissue quality and integrity.

  8. A new osteonecrosis animal model of the femoral head induced by microwave heating and repaired with tissue engineered bone

    PubMed Central

    Han, Rui; Geng, Chengkui; Wang, Yongnian; Wei, Lei

    2008-01-01

    The objective of this research was to induce a new animal model of osteonecrosis of the femoral head (ONFH) by microwave heating and then repair with tissue engineered bone. The bilateral femoral heads of 84 rabbits were heated by microwave at various temperatures. Tissue engineered bone was used to repair the osteonecrosis of femoral heads induced by microwave heating. The roentgenographic and histological examinations were used to evaluate the results. The femoral heads heated at 55°C for ten minutes showed low density and cystic changes in X-ray photographs, osteonecrosis and repair occurred simultaneously in histology at four and eight weeks, and 69% femoral heads collapsed at 12 weeks. The ability of tissue engineered bone to repair the osteonecrosis was close to that of cancellous bone autograft. The new animal model of ONFH could be induced by microwave heating, and the tissue engineering technique will provide an effective treatment. PMID:18956184

  9. Is there any information on micro-structure in microwave tomography of bone tissue?

    PubMed

    Irastorza, R M; Carlevaro, C M; Vericat, F

    2013-08-01

    In this work, two-dimensional simulations of the microwave dielectric properties of models with ellipses and realistic models of trabecular bone tissue are performed. In these simulations, finite difference time domain methodology has been applied to simulate two-phase structures containing inclusions. The results presented here show that the micro-structure is an important factor in the effective dielectric properties of trabecular bone. We consider the feasibility of using the dielectric behaviour of bone tissue to be an indicator of bone health. The frequency used was 950 MHz. It was found that the dielectric properties can be used as an estimate of the degree of anisotropy of the micro-structure of the trabecular tissue. Conductivity appears to be the most sensitive parameter in this respect. Models with ellipse shaped-inclusions are also tested to study their application to modelling bone tissue. Models with ellipses that had an aspect ratio of a/b=1.5 showed relatively good agreement when compared with realistic models of bone tissue. According to the results presented here, the anisotropy of trabecular bone must be accounted for when measuring its dielectric properties using microwave imaging.

  10. Electromagnetic Spectroscopy of Normal Breast Tissue Specimens Obtained From Reduction Surgeries: Comparison of Optical and Microwave Properties

    PubMed Central

    Lazebnik, Mariya; Zhu, Changfang; Palmer, Gregory M.; Harter, Josephine; Sewall, Sarah; Ramanujam, Nirmala; Hagness, Susan C.

    2009-01-01

    Techniques utilizing electromagnetic energy at microwave and optical frequencies have been shown to be promising for breast cancer detection and diagnosis. Since different biophysical mechanisms are exploited at these frequencies to discriminate between healthy and diseased tissue, combining these two modalities may result in a more powerful approach for breast cancer detection and diagnosis. Toward this end, we performed microwave dielectric spectroscopy and optical diffuse reflectance spectroscopy measurements at the same sites on freshly-excised normal breast tissues obtained from reduction surgeries at the University of Wisconsin Hospital, using microwave and optical probes with very similar sensing volumes. We found that the microwave dielectric constant and effective conductivity are correlated with tissue composition across the entire measurement frequency range (|r|~0.5–0.6, p<0.01), and that the optical absorption coefficient at 460 nm and optical scattering coefficient are correlated with tissue composition (|r|~ 0.4–0.6, p<0.02). Finally, we found that the optical absorption coefficient at 460 nm is correlated with the microwave dielectric constant and effective conductivity (r=−0.55, p<0.01). Our results suggest that combining optical and microwave modalities for analyzing breast tissue samples may serve as a crosscheck and provide complementary information about tissue composition. PMID:18838370

  11. Investigation of the thermal and tissue injury behavior in microwave thermal therapy of the porcine kidney

    NASA Astrophysics Data System (ADS)

    He, Xiaoming; Mcgee, Shawn; Coad, James E.; Schmidlin, Franz R.; Iaizzo, Paul; Swanlund, David J.; Rudie, Eric; Kluge, Stan; Bischof, John C.

    2003-06-01

    In this paper, we report the characterization of microwave therapy in normal porcine kidneys both in vitro and in vivo. This technology is being developed for eventual use in the treatment of small renal cell carcinomas (RCC) using minimally invasive procedures. Microwave energy was applied through an interstitial microwave probe (Urologix, Plymouth, MN) to the kidney cortex with involvement of the medulary region. The thermal histories at several locations were recorded. After treatment, the kidneys were bisected and tissue sections were prepared for histologic study at approximately the same depth as the thermal probe. Histologic cellular injury and microvascular stasis were quantitatively evaluated. Absolute rate kinetic models of cellular injury and vascular stasis were fit to the thermal and histologic data to determine the kinetic parameters. A 3-D finite element thermal model based on the Pennes Bioheat equation was developed and solved using a commercial software package (ANSYS, V5.7). The specific absorption rate (SAR) of the microwave probe was measured experimentally. This is the first thermal model validated using measured in vitro thermal histories and then used to determine the blood perfusion term in vivo.

  12. Computer modeling of electromagnetic and thermal effects in microwave soft tissue ablation (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Cronin, Nigel J.; Clegg, Peter J.

    2005-04-01

    Microwave Endometrial Ablation (MEA) is a technique that can be used for the treatment of abnormal uterine bleeding. The procedure involves sweeping a specially designed microwave applicator throughout the uterine cavity to achieve an ideally uniform depth of tissue necrosis of between 5 and 6mm. We have performed a computer analysis of the MEA procedure in which finite element analysis was used to determine the SAR pattern around the applicator. This was followed by a Green Function based solution of the Bioheat equation to determine the resulting induced temperatures. The method developed is applicable to situations involving a moving microwave source, as used in MEA. The validity of the simulation was verified by measurements in a tissue phantom material using a purpose built applicator and a calibrated pulling device. From the calculated temperatures the depth of necrosis was assessed through integration of the resulting rates of cell death estimated using the Arrhenius equation. The Arrhenius parameters used were derived from published data on BHK cells. Good agreement was seen between the calculated depths of cell necrosis and those found in human in-vivo testing.

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

    PubMed Central

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

    2014-01-01

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

  14. Average dielectric property analysis of complex breast tissue with microwave transmission measurements.

    PubMed

    Garrett, John D; Fear, Elise C

    2015-01-09

    Prior information about the average dielectric properties of breast tissue can be implemented in microwave breast imaging techniques to improve the results. Rapidly providing this information relies on acquiring a limited number of measurements and processing these measurement with efficient algorithms. Previously, systems were developed to measure the transmission of microwave signals through breast tissue, and simplifications were applied to estimate the average properties. These methods provided reasonable estimates, but they were sensitive to multipath. In this paper, a new technique to analyze the average properties of breast tissues while addressing multipath is presented. Three steps are used to process transmission measurements. First, the effects of multipath were removed. In cases where multipath is present, multiple peaks were observed in the time domain. A Tukey window was used to time-gate a single peak and, therefore, select a single path through the breast. Second, the antenna response was deconvolved from the transmission coefficient to isolate the response from the tissue in the breast interior. The antenna response was determined through simulations. Finally, the complex permittivity was estimated using an iterative approach. This technique was validated using simulated and physical homogeneous breast models and tested with results taken from a recent patient study.

  15. Average Dielectric Property Analysis of Complex Breast Tissue with Microwave Transmission Measurements

    PubMed Central

    Garrett, John D.; Fear, Elise C.

    2015-01-01

    Prior information about the average dielectric properties of breast tissue can be implemented in microwave breast imaging techniques to improve the results. Rapidly providing this information relies on acquiring a limited number of measurements and processing these measurement with efficient algorithms. Previously, systems were developed to measure the transmission of microwave signals through breast tissue, and simplifications were applied to estimate the average properties. These methods provided reasonable estimates, but they were sensitive to multipath. In this paper, a new technique to analyze the average properties of breast tissues while addressing multipath is presented. Three steps are used to process transmission measurements. First, the effects of multipath were removed. In cases where multipath is present, multiple peaks were observed in the time domain. A Tukey window was used to time-gate a single peak and, therefore, select a single path through the breast. Second, the antenna response was deconvolved from the transmission coefficient to isolate the response from the tissue in the breast interior. The antenna response was determined through simulations. Finally, the complex permittivity was estimated using an iterative approach. This technique was validated using simulated and physical homogeneous breast models and tested with results taken from a recent patient study. PMID:25585106

  16. A method for determination of selenium in organic tissues using microwave digestion and liquid chromatography.

    PubMed

    Govasmark, Espen; Grimmett, Mark G

    2007-01-01

    An existing laboratory procedure for selenium analysis using open-vessel wet digestion and liquid chromatographic fluorescence determination was modified for use with microwave digestion. The proposed microwave digestion method eliminated the hazards associated with the use of HClO4 while maintaining excellent recoveries of selenium. A 2-step HNO3/H2O2 digestion procedure was developed. Digested samples were derivatized with 2,3-diaminonaphthalene, and the resultant piazselenol complex was measured fluorometrically using a liquid chromatograph. Measured values were in agreement with 9 different certified reference materials. The detection limit for this method was 0.54 ng Se/g tissue (3 sigma), and the calibration curve remained linear (r2 = 0.9968) up to 2 microg Se/g.

  17. Numerical simulation of microwave ablation incorporating tissue contraction based on thermal dose

    NASA Astrophysics Data System (ADS)

    Liu, Dong; Brace, Christopher L.

    2017-03-01

    Tissue contraction plays an important role during high temperature tumor ablation, particularly during device characterization, treatment planning and imaging follow up. We measured such contraction in 18 ex vivo bovine liver samples during microwave ablation by tracking fiducial motion on CT imaging. Contraction was then described using a thermal dose dependent model and a negative thermal expansion coefficient based on the empirical data. FEM simulations with integrated electromagnetic wave propagation, heat transfer, and structural mechanics were evaluated using temperature-dependent dielectric properties and the negative thermal expansion models. Simulated temperature and displacement curves were then compared with the ex vivo experimental results on different continuous output powers. The optimized thermal dose model indicated over 50% volumetric contraction occurred at the temperature over 102.1 °C. The numerical simulation results on temperature and contraction-induced displacement showed a good agreement with experimental results. At microwave powers of 55 W, the mean errors on temperature between simulation and experimental results were 8.25%, 2.19% and 5.67% at 5 mm, 10 mm and 20 mm radially from the antenna, respectively. The simulated displacements had mean errors of 16.60%, 14.08% and 23.45% at the same radial locations. Compared to the experimental results, the simulations at the other microwave powers had larger errors with 10–40% mean errors at 40 W, and 10–30% mean errors at 25 W. The proposed model is able to predict temperature elevation and simulate tissue deformation during microwave ablation, and therefore may be incorporated into treatment planning and clinical translation from numerical simulations.

  18. Platelet coagulation-protein interactions.

    PubMed

    Walsh, Peter N

    2004-08-01

    The biochemical mechanisms by which activated platelets participate in exposing receptors for the assembly of enzyme-cofactor-substrate complexes at all stages of the blood coagulation cascade are reviewed. Information derived from studies conducted during the last 30 years supports the concept that the initiation of blood coagulation is triggered by exposure of tissue factor at injury sites, leading to the generation of minute quantities of thrombin (limited by tissue factor pathway inhibitor), sufficient to activate platelets, factors XI, VIII, and V, and trigger the consolidation pathway (i.e., the sequential activation of factors XI, IX, X, and prothrombin on the activated platelet surface), leading to the generation of sufficient thrombin to convert fibrinogen to fibrin and effect hemostasis. Platelets localize coagulation to the hemostatic thrombus and protect coagulation enzymes from inhibition by both plasma and platelet inhibitors (e.g., protease nexin 2), thus preventing disseminated intravascular coagulation.

  19. Planar Microwave Sensor for Theranostic Therapy of Organic Tissue Based on Oval Split Ring Resonators

    PubMed Central

    Reimann, Carolin; Puentes, Margarita; Maasch, Matthias; Hübner, Frank; Bazrafshan, Babak; Vogl, Thomas J.; Damm, Christian; Jakoby, Rolf

    2016-01-01

    Microwave sensors in medical environments play a significant role due to the contact-less and non-invasive sensing mechanism to determine dielectric properties of tissue. In this work, a theranostic sensor based on Split Ring Resonators (SRRs) is presented that provides two operation modes to detect and treat tumor cells, exemplary in the liver. For the detection mode, resonance frequency changes due to abnormalities are evaluated, and in the treatment mode, microwave ablation is performed. The planar sensor structure can be integrated into a needle like a surgery tool that evokes challenges concerning size limitations and biocompatibility. To meet the size requirements and provide a reasonable operating frequency, properties of oval shaped SRRs are investigated. By elongating the radius of the SRR in one direction, the resonance frequency can be decreased significantly compared to circular SRR by a factor of two below 12 GHz. In order to validate the detection and treatment characteristics of the sensor, full wave simulations and measurements are examined. Clear resonance shifts are detected for loading the sensor structures with phantoms mimicking healthy and malignant tissue. For treatment mode evaluation, ex vivo beef liver tissue was ablated leading to a lesion zone 1.2 cm × 1 cm × 0.3 cm with a three minute exposure of maximum 2.1 W. PMID:27618050

  20. Blood Coagulation, Inflammation and Malaria

    PubMed Central

    Francischetti, Ivo M. B.; Seydel, Karl B.; Monteiro, Robson Q.

    2010-01-01

    I. ABSTRACT Malaria remains a highly prevalent disease in more than 90 countries and accounts for at least 1 million deaths every year. Plasmodium falciparum infection is often associated with a procoagulant tonus characterized by thrombocytopenia and activation of the coagulation cascade and fibrinolytic system; however, bleeding and hemorrhage are uncommon events, suggesting that a compensated state of blood coagulation activation occurs in malaria. This article i) reviews the literature related to blood coagulation and malaria in a historic perspective, ii) describes basic mechanisms of coagulation, anticoagulation, and fibrinolysis, iii) explains the laboratory changes in acute and compensated disseminated intravascular coagulation (DIC), iv) discusses the implications of tissue factor (TF) expression in the endothelium of P. falciparum-infected patients, and v) emphasizes the pro-coagulant role of parasitized erythrocytes (pRBC) and activated platelets in the pathogenesis of malaria. This article also presents the ‘Tissue Factor Model’ (TFM) for malaria pathogenesis, which places TF as the interface between sequestration, endothelial cell activation, blood coagulation disorder and inflammation often associated with the disease. The relevance of the coagulation-inflammation cycle for the multiorgan dysfunction and coma is discussed in the context of malaria pathogenesis. PMID:18260002

  1. Multimode near-field microwave monitoring of free water content of skin and imaging of tissue.

    PubMed

    Lofland, S E; Mazzatenta, J D; Croman, J; Tyagi, S D

    2007-03-07

    We have used the near-field scanning microwave microscopy (NSMM) technique in the 1-10 GHz range to monitor the free water content of skin. The water content is interpreted from the measured dielectric properties of the epidermis. The finger skin was first hydrated by soaking in water at 37 degrees C for 30 min followed by monitoring of water content as the free water evaporated under ambient conditions. The same technique has also been employed to image a 1 cm x 1 cm sample of chicken skin. It has been shown that variations exist in the resonant frequencies and quality factors of tissue under varying physical parameters. The samples analysed were as-received and thermally dehydrated or damaged chicken tissue samples. We contrast between the dielectric properties with the optical images. We also discuss possible application of our imaging technique in clinical monitoring of the wound healing process.

  2. Changes of amino acid gradients in brain tissues induced by microwave irradiation and other means

    SciTech Connect

    Baxter, C.F.; Parsons, J.E.; Oh, C.C.; Wasterlain, C.G.; Baldwin, R.A. )

    1989-09-01

    Focused microwave irradiation to the head (FMI) has been used extensively by neurochemists for rapid inactivation of enzymatic activity in brain tissues and the preservation, for in vitro analysis, of in vivo substrate concentrations. Periodically the suitability of this technique for regional studies has been questioned. Evidence has now been obtained, on the basis of altered concentration gradients for GABA and taurine from the Substantia Nigra (SN) to an Adjacent Dorsal Area (ADJ), that FMI not only inactivates enzymes, but also facilitates rapid diffusion of small molecules from areas of high concentrations to adjacent areas of lower concentration. To a lesser extent, the implantation of plastic injection cannulas also decreased these concentration gradients. These results offer clear evidence that FMI is ill suited and unreliable for studies designed to map and compare the in vivo regional concentrations of diffusible organic molecules (such as amino acids) in brain tissues. Any invasive technique that compromises membrane barriers is likely to produce smaller similar effects.

  3. Three-Dimensional Near-Field Microwave Holography for Tissue Imaging

    PubMed Central

    Amineh, Reza K.; Khalatpour, Ali; Xu, Haohan; Baskharoun, Yona; Nikolova, Natalia K.

    2012-01-01

    This paper reports the progress toward a fast and reliable microwave imaging setup for tissue imaging exploiting near-field holographic reconstruction. The setup consists of two wideband TEM horn antennas aligned along each other's boresight and performing a rectangular aperture raster scan. The tissue sensing is performed without coupling liquids. At each scanning position, wideband data is acquired. Then, novel holographic imaging algorithms are implemented to provide three-dimensional images of the inspected domain. In these new algorithms, the required incident field and Green's function are obtained from numerical simulations. They replace the plane (or spherical) wave assumption in the previous holographic methods and enable accurate near-field imaging results. Here, we prove that both the incident field and Green's function can be obtained from a single numerical simulation. This eliminates the need for optimization-based deblurring which was previously employed to remove the effect of realistic non-point-wise antennas. PMID:22550472

  4. Feasibility of salvage interstitial microwave thermal therapy for prostate carcinoma following failed brachytherapy: studies in a tissue equivalent phantom.

    PubMed

    McCann, Claire; Kumaradas, J Carl; Gertner, Mark R; Davidson, Sean R H; Dolan, Alfred M; Sherar, Michael D

    2003-04-21

    Thermal therapy is an experimental treatment to destroy solid tumours by heating them to temperatures ranging from 55 degrees C to 90 degrees C, inducing thermal coagulation and necrosis of the tumour. We are investigating the feasibility of interstitial microwave thermal therapy as a salvage treatment for prostate cancer patients with local recurrence following failed brachytherapy. Due to the electrical and thermal conductivity of the brachytherapy seeds, we hypothesized that the seeds could scatter the microwave energy and cause unpredictable heating. To investigate this, a 915 MHz helical antenna was inserted into a muscle-equivalent phantom with and without brachytherapy seeds. Following a 10 W, 5 s input to the antenna, the temperature rise was used to calculate absorbed power, also referred to as specific absorption rate (SAR). Plane wave models based on Maxwell's equations were also used to characterize the electromagnetic scattering effect of the seeds. In addition, the phantom was heated with 8 W for 5 min to quantify the effect of the seeds on the temperature distribution during extended heating. SAR measurements indicated that the seeds had no significant effect on the shape and size of the SAR pattern of the antenna. However, the plane wave simulations indicated that the seeds could scatter the microwave energy resulting in hot spots at the seed edges. Lack of experimental evidence of these hot spots was probably due to the complex polarization of the microwaves emitted by the helical antenna. Extended heating experiments also demonstrated that the seeds had no significant effect on the temperature distributions and rates of temperature rise measured in the phantom. The results indicate that brachytherapy seeds are not a technical impediment to interstitial microwave thermal therapy as a salvage treatment following failed brachytherapy.

  5. Feasibility of salvage interstitial microwave thermal therapy for prostate carcinoma following failed brachytherapy: studies in a tissue equivalent phantom

    NASA Astrophysics Data System (ADS)

    McCann, Claire; Kumaradas, J. Carl; Gertner, Mark R.; Davidson, Sean R. H.; Dolan, Alfred M.; Sherar, Michael D.

    2003-04-01

    Thermal therapy is an experimental treatment to destroy solid tumours by heating them to temperatures ranging from 55 °C to 90 °C, inducing thermal coagulation and necrosis of the tumour. We are investigating the feasibility of interstitial microwave thermal therapy as a salvage treatment for prostate cancer patients with local recurrence following failed brachytherapy. Due to the electrical and thermal conductivity of the brachytherapy seeds, we hypothesized that the seeds could scatter the microwave energy and cause unpredictable heating. To investigate this, a 915 MHz helical antenna was inserted into a muscle-equivalent phantom with and without brachytherapy seeds. Following a 10 W, 5 s input to the antenna, the temperature rise was used to calculate absorbed power, also referred to as specific absorption rate (SAR). Plane wave models based on Maxwell's equations were also used to characterize the electromagnetic scattering effect of the seeds. In addition, the phantom was heated with 8 W for 5 min to quantify the effect of the seeds on the temperature distribution during extended heating. SAR measurements indicated that the seeds had no significant effect on the shape and size of the SAR pattern of the antenna. However, the plane wave simulations indicated that the seeds could scatter the microwave energy resulting in hot spots at the seed edges. Lack of experimental evidence of these hot spots was probably due to the complex polarization of the microwaves emitted by the helical antenna. Extended heating experiments also demonstrated that the seeds had no significant effect on the temperature distributions and rates of temperature rise measured in the phantom. The results indicate that brachytherapy seeds are not a technical impediment to interstitial microwave thermal therapy as a salvage treatment following failed brachytherapy.

  6. CT imaging during microwave ablation: Analysis of spatial and temporal tissue contraction

    SciTech Connect

    Liu, Dong; Brace, Christopher L.

    2014-11-01

    Purpose: To analyze the spatial distribution and temporal development of liver tissue contraction during high-temperature ablation by using intraprocedural computed tomography (CT) imaging. Methods: A total of 46 aluminum fiducial markers were positioned in a 60 × 45 mm grid, in a single plane, around a microwave ablation antenna in each of six ex vivo bovine liver samples. Ablations were performed for 10 min at 100 W. CT data of the liver sample were acquired every 30 s during ablation. Fiducial motion between acquisitions was tracked in postprocessing and used to calculate measures of tissue contraction and contraction rates. The spatial distribution and temporal evolution of contraction were analyzed. Results: Fiducial displacement indicated that the zone measured postablation was 8.2 ± 1.8 mm (∼20%) smaller in the radial direction and 7.1 ± 1.0 mm (∼10%) shorter in the longitudinal direction than the preablation tissue dimension. Therefore, the total ablation volume was reduced from its preablation value by approximately 45%. Very little longitudinal contraction was noted in the distal portion of the ablation zone. Central tissues contracted more than 60%, which was near an estimated limit of ∼70% based on initial water content. More peripheral tissues contracted only 15% in any direction. Contraction rates peaked during the first 60 s of heating with a roughly exponential decay over time. Conclusions: Ablation zones measured posttreatment are significantly smaller than the pretreatment tissue dimensions. Tissue contraction is spatially dependent, with the greatest effect occurring in the central ablation zone. Contraction rate peaks early and decays over time.

  7. Design and realisation of tissue-equivalent dielectric simulators for dosimetric studies on microwave antennas for interstitial ablation.

    PubMed

    Lopresto, V; Pinto, R; Lodato, R; Lovisolo, G A; Cavagnaro, M

    2012-07-01

    Thermal ablation therapies, based on electromagnetic field sources (interstitial or intracavitary antennas) at radio and microwave frequencies, are increasingly used in medicine due to their proven efficacy in the treatment of many diseases (tumours, stenosis, etc). Such techniques need standardized procedures, still not completely consolidated, as to analyze the behaviour of antennas for treatment optimisation. Several tissue-equivalent dielectric simulators (also named phantoms) have been developed to represent human head tissues, and extensively used in the analysis of human exposure to the electromagnetic emissions from hand-held devices; yet, very few studies have considered other tissues, as those met in ablation therapies. The objective of this study was to develop phantoms of liver and kidney tissue to experimentally characterise interstitial microwave antennas in reference conditions. Phantom properties depend on the simulated target tissue (liver or kidney) and the considered frequency (2.45 GHz in this work), addressing the need for a transparent liquid to easily control the positioning of the probe with respect to the antenna under test. An experimental set-up was also developed and used to characterise microwave ablation antenna performances. Finally, a comparison between measurements and numerical simulations was performed for the cross-validation of the experimental set-up and the numerical model. The obtained results highlight the fundamental role played by dielectric simulators in the development of microwave ablation devices, representing the first step towards the definition of a procedure for the ablation treatment planning.

  8. Microwaves and tea: new tools to process plant tissue for transmission electron microscopy.

    PubMed

    Carpentier, Anaïs; Abreu, Susana; Trichet, Michael; Satiat-Jeunemaitre, Béatrice

    2012-07-01

    Optimizing sample processing, reducing the duration of the preparation of specimen, and adjusting procedures to adhere to new health and safety regulations, are the current challenges of plant electron microscopists. To address these issues, plant processing protocols for TEM, combining the use of polyphenolic compounds as substitute for uranyl acetate with microwave technology are being developed. In the present work, we optimized microwave-assisted processing of different types of plant tissue for ultrastuctural and immunocytochemical studies. We also explored Oolong tea extract as alternative for uranyl acetate for the staining of plant samples. We obtained excellent preservation of cell ultrastructure when samples were embedded in epoxy resin, and of cell antigenicity, when embedded in LR-White resin. Furthermore, Oolong tea extract successfully replaced uranyl acetate as a counterstain on ultrathin sections, and for in block staining. These novel protocols reduce the time spent at the bench, and improve safety conditions for the investigator. The preservation of the cell components when following these approaches is of high quality. Altogether, they offer significant simplification of the procedures required for electron microscopy of plant ultrastructure.

  9. The reciprocal relationship between inflammation and coagulation.

    PubMed

    O'Brien, Mauria

    2012-05-01

    Inflammation and coagulation constitute two host defense systems with complementary roles in eliminating invading pathogens, limiting tissue damage, and restoring homeostasis. Extensive cross talk exists between these 2 systems, whereby inflammation leads to activation of coagulation, and coagulation considerably affects inflammatory activity. Infection leads to the production of proinflammatory cytokines that, in turn, stimulate the production of tissue factor. Activation of the coagulation system and ensuing thrombin generation are dependent on the expression of tissue factor. Conversely, activated coagulation proteases may affect specific receptors on inflammatory cells and endothelial cells and thereby modulate the inflammatory response. Activation of coagulation with the simultaneous down-regulation of endothelial-bound anticoagulant mechanisms and endogenous fibrinolysis characterizes the pathophysiology of sepsis. The mechanisms by which these highly complex and codependent defense strategies are linked together both in health and disease is the focus of this review.

  10. Dual-mode antenna design for microwave heating and noninvasive thermometry of superficial tissue disease.

    PubMed

    Jacobsen, S; Stauffer, P R; Neuman, D G

    2000-11-01

    Hyperthermia therapy of superficial skin disease has proven clinically useful, but current heating equipment is somewhat clumsy and technically inadequate for many patients. The present effort describes a dual-purpose, conformal microwave applicator that is fabricated from thin, flexible, multilayer printed circuit board (PCB) material to facilitate heating of surface areas overlaying contoured anatomy. Preliminary studies document the feasibility of combining Archimedean spiral microstrip antennas, located concentrically within the central region of square dual concentric conductor (DCC) annular slot antennas. The motivation is to achieve homogeneous tissue heating simultaneously with noninvasive thermometry by radiometric sensing of blackbody radiation from the target tissue under the applicator. Results demonstrate that the two antennas have complimentary regions of influence. The DCC ring antenna structure produces a peripherally enhanced power deposition pattern with peaks in the outer corners of the aperture and a broad minimum around 50% of maximum centrally. In contrast, the Archimedean spiral radiates (or receives) energy predominantly along the boresight axis of the spiral, thus confining the region of influence to tissue located within the central broad minimum of the DCC pattern. Analysis of the temperature-dependent radiometer signal (brightness temperature) showed linear correlation of radiometer output with test load temperature using either the spiral or DCC structure as the receive antenna. The radiometric performance of the broadband Archimedean antenna was superior compared to the DCC, providing improved temperature resolution (0.1 degree C-0.2 degree C) and signal sensitivity (0.3 degree C-0.8 degree C/degree C) at all four 500 MHz integration bandwidths tested within the frequency range from 1.2 to 3.0 GHz.

  11. [Use in immunohistochemical studies of a method of restoration of antigenic specificity as affected by microwaves in tissue fixed with formalin and embedded in paraffin].

    PubMed

    Gurevich, L E; Isakov, V A

    1999-01-01

    Recovery of specific antigenic characteristics using microwave treatment of paraffin sections of tissues fixed by formalin allows to extend spectrum of antibodies for immunohistochemical diagnosis. Microwaves enable the reaction on the material prepared according to the standard technique, and macropreparations long stored in formalin and archive blocks.

  12. Microwave ablation devices for interventional oncology.

    PubMed

    Ward, Robert C; Healey, Terrance T; Dupuy, Damian E

    2013-03-01

    Microwave ablation is one of the several options in the ablation armamentarium for the treatment of malignancy, offering several potential benefits when compared with other ablation, radiation, surgical and medical treatment modalities. The basic microwave system consists of the generator, power distribution system and antennas. Often under image (computed tomography or ultrasound) guidance, a needle-like antenna is inserted percutaneously into the tumor, where local microwave electromagnetic radiation is emitted from the probe's active tip, producing frictional tissue heating, capable of causing cell death by coagulation necrosis. Half of the microwave ablation systems use a 915 MHz generator and the other half use a 2450 MHz generator. To date, there are no completed clinical trials comparing microwave devices head-to-head. Prospective comparisons of microwave technology with other treatment alternatives, as well as head-to-head comparison with each microwave device, is needed if this promising field will garner more widespread support and use in the oncology community.

  13. Microwave Therapy for Bone Tumors

    NASA Astrophysics Data System (ADS)

    Takakuda, Kazuo; Inaoka, Shuken; Saito, Hirokazu; Hassan, Moinuddin; Koyama, Yoshikazu; Kuroda, Hiroshi; Kanaya, Tomohiro; Kosaka, Toshifumi; Tanaka, Shigeo; Miyairi, Hiroo; Shinomiya, Kenichi

    In vivo microwave treatments for bone tumor are designed, which enable us to conserve the activity and functionality of the matrix of living tissues. This treatment is composed of two steps. In the first step, the tumor was coagulated by the application of microwaves emitted from the antenna inserted into the tumor tissue, and then removed. In the second step, the surrounding tissue suspected to be invaded with transformed cells was covered with hydro gels and heated similarly. The tissue itself was heated by the conduction from the gels. The tissue temperature should be kept at 60°C for 30 minutes. This treatment should kill the whole cells within the tissues, but the mechanical strength and the biochemical activity of the matrix should be left intact. The matrix preserves the mechanical functions and ensures the maximum regeneration ability of the tissue. In this study, various hydro gels were examined and the most promising one was selected. Animal experiments were carried out and successful heating verified the applicability of the treatment.

  14. [Determination of thirty three elements in lung cancer tissues of patients with lung cancer by microwave digestion-ICP-MS].

    PubMed

    Zhang, Lin-Lin; Ma, Qian-Li; Huang, Yun-Chao; Wu, Guo-Ping; Wei, Fu-Sheng

    2009-12-01

    A method for determining 33 elements in lung tissues of patients with lung cancer was developed by using vacuum freeze-drying microwave digestion-ICP-MS. The lung tissue samples were treated by vacuum freeze-drying equipment. After microwave digestion in HNO3-H2O2 solution system, the samples were diluted with the method of constant volume. Under the optimized conditions the samples were analyzed by ICP-MS. The double internal standard elements Rh and Re were used to compensate for matrix suppression effect and sensitivity drift. The analytical results showed that the detection limits of the 33 elements were 0.01-0.45 ng x mL(-1). The national standard reference material GBW(E)080193 bovine liver was analyzed by the described method and the measured element values accorded with the standard values or the reference values. The relative standard deviation (RSD) of the method was 2.1%-14.3%. The recovery rates of the studied elements were 90.1%-117.5%. The contents of 33 elements in lung cancer tissues, paracancerous lung tissues and benign lung tissues of 6 patients with lung cancer were determined by the method. It was indicated that the method is rapid, simple and accurate for determining multi-elements in human lung tissue and other biological samples.

  15. Inherited disorders of blood coagulation.

    PubMed

    Lippi, Giuseppe; Franchini, Massimo; Montagnana, Martina; Favaloro, Emmanuel J

    2012-08-01

    Hemostasis is traditionally defined as a physiological response to blood vessel injury and bleeding, which entails a co-ordinated process involving the blood vessel, platelets, and blood clotting proteins (i.e. coagulation factors). Hemostasis can be divided into primary and secondary components. The former rapidly initiates after endothelial damage and is characterized by vascular contraction, platelet adhesion, and formation of a soft aggregate plug. The latter is initiated following the release of tissue factor and involves a complex sequence of events known as the blood coagulation cascade, encompassing serial steps where each coagulation factor activates another in a chain reaction that culminates in the conversion of fibrinogen to fibrin. Patients carrying abnormalities of the coagulation cascade (i.e. deficiencies of coagulation factors) have an increased bleeding tendency, where the clinical severity is mostly dependent upon the type and the plasma level of the factor affected. These disorders also impose a heavy medical and economic burden on individual patients and society in general. The aim of this article is to provide a general overview on the pathophysiology, clinics, diagnostics, and therapy of inherited disorders of coagulation factors.

  16. Systems Biology of Coagulation

    PubMed Central

    Diamond, Scott L.

    2013-01-01

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

  17. Coagulation in patients with severe sepsis.

    PubMed

    Levi, Marcel; Poll, Tom van der

    2015-02-01

    In the majority of patients with severe sepsis, systemic activation of coagulation is present. Increasing evidence points to an extensive cross-talk between coagulation and inflammation that may play an important role in the pathogenesis of sepsis. Inflammation not only leads to activation of coagulation, but coagulation also considerably affects inflammatory activity. Molecular pathways that contribute to inflammation-induced activation of coagulation have been precisely identified. Proinflammatory cytokines and other mediators are capable of activating the coagulation system and downregulating important physiological anticoagulant pathways. Activation of the coagulation system and ensuing thrombin generation is dependent on expression of tissue factor on activated mononuclear cells and endothelial cells, and is insufficiently counteracted by TFPI. Simultaneously, endothelial-bound anticoagulant mechanism, in particular the protein C system, is shutoff by proinflammatory cytokines. In addition, fibrin removal is severely inhibited, because of inactivation of the fibrinolytic system, caused by an upregulation of its main inhibitor, plasminogen activator inhibitor type 1 (PAI-1). Increased fibrin formation and impaired removal lead to (micro)vascular thrombosis, which may result in tissue ischemia and subsequent organ damage. The cornerstone of the management of coagulation in sepsis is the specific and vigorous treatment of the underlying disorder. Strategies aimed at the inhibition of coagulation activation may theoretically be justified and have been found beneficial in experimental and initial clinical studies. Heparin may be an effective anticoagulant approach and alternative strategies comprise restoration of physiological anticoagulant pathways.

  18. Microwave-assisted tissue processing for same-day EM-diagnosis of potential bioterrorism and clinical samples.

    PubMed

    Schroeder, Josef A; Gelderblom, Hans R; Hauroeder, Baerbel; Schmetz, Christel; Milios, Jim; Hofstaedter, Ferdinand

    2006-01-01

    The purpose of this study was to explore the turnaround times, section and image quality of a number of more "difficult" specimens destined for rapid diagnostic electron microscopy (EM) after microwave-assisted processing. The results were assessed and compared with those of conventionally processed samples. A variety of infectious agents, some with a potential for bioterrorism, and liver biopsies serving as an example for routine histopathology samples were studied. The samples represented virus-producing cell cultures (such as SARS-coronavirus, West Nile virus, Orthopox virus), bacteria suspensions (cultures of Escherichia coli and genetically knockout apathogenic Bacillus anthracis), suspensions of parasites (malaria Plasmodium falciparum, Leishmania major, Microsporidia cuniculi, Caenorhabditis elegans), and whole Drosophila melanogaster flies infected with microsporidia. Fresh liver samples and infected flies were fixed in Karnovsky-fixative by microwaving (20 min), all other samples were fixed in buffered glutaraldehyde or Karnovsky-fixative overnight or longer. Subsequently, all samples were divided to evaluate alternative processing protocols: one part of the sample was OsO4-postfixed, ethanol-dehydrated, Epon-infiltrated (overnight) in an automated tissue processor (LYNX, Leica), and polymerized at 60 degrees C for 48 h; in parallel the other part was microwave-assisted processed in the bench microwave device (REM, Milestone), including post-osmication and the resin block polymerization. The microwave-assisted processing protocol required at minimum 3 h 20 min: the respective epon resin blocks were uniformly polymerized allowing an easy sectioning of semi- and ultrathin sections. Sections collected on non-coated 200 mesh grids were stable in the electron beam and showed an excellent preservation of the ultrastructure and high contrast, thus allowing an easy, unequivocal and rapid assessment of specimens. Compared with conventional routine methods

  19. Investigation of the thermal and tissue injury behaviour in microwave thermal therapy using a porcine kidney model.

    PubMed

    He, X; McGee, S; Coad, J E; Schmidlin, F; Iaizzo, P A; Swanlund, D J; Kluge, S; Rudie, E; Bischof, J C

    2004-09-01

    Minimally invasive microwave thermal therapies are being developed for the treatment of small renal cell carcinomas (RCC, d<3 cm). This study assessed the thermal history and corresponding tissue injury patterns resulting from microwave treatment of the porcine renal cortex. Three groups of kidneys were evaluated: (1) in vitro treated, (2) in vivo with 2-h post-treatment perfusion (acute) and (3) in vivo with 7-day post-treatment perfusion (chronic). The kidneys were treated with an interstitial water-cooled microwave probe (Urologix, Plymouth, MN) that created a lesion centered in the renal cortex (50 W for 10 min). The thermal histories were recorded at 0.5 cm radial intervals from the probe axis for correlation with the histologic cellular and vascular injury. The kidneys showed a reproducible 2 cm chronic lesion with distinct histologic injury zones identified. The thermal histories at the edge of these zones were found using Lagrangian interpolation. The threshold thermal histories for microvascular injury and stasis appeared to be lower than that for renal epithelial cell injury. The Arrhenius kinetic injury models were fit to the thermal histories and injury data to determine the kinetic parameters (i.e. activation energy and frequency factor) for the thermal injury processes. The resultant activation energies are consistent in magnitude with those for thermally induced protein denaturation. A 3-D finite element thermal model based on the Pennes bioheat equation was developed and solved using ANSYS (V7.0). The real geometry of the kidneys studied and temperature dependent thermal properties were used in this model. The specific absorption rate (SAR) of the microwave probe required for the thermal modelling was experimentally determined. The results from the thermal modelling suggest that the complicated change of local renal blood perfusion with temperature and time during microwave thermal therapy can be predicted, although a first order kinetic model may

  20. Thermal Ablation of Lung Tissue: In Vivo Experimental Comparison of Microwave and Radiofrequency

    SciTech Connect

    Crocetti, Laura Bozzi, Elena; Faviana, Pinuccia; Cioni, Dania; Della Pina, Clotilde; Sbrana, Alberto; Fontanini, Gabriella; Lencioni, Riccardo

    2010-08-15

    This study was designed to compare feasibility, safety, and effectiveness of microwave (MW) ablation versus radiofrequency (RF) ablation of lung tissue in a rabbit model. Twenty New Zealand White rabbits were submitted to MW (n = 10, group A) or RF ablation (n = 10, group B). The procedures were performed with a prototype MW ablation device with a 1.6-cm radiating section antenna (Valleylab MW Ablation System) and with a 2-cm exposed-tip RF electrode (Cool-tip RF Ablation System). At immediate computed tomography increase in density, maximum diameters (D1-D3) of ablation zones were measured and ablation volume was calculated. Histopathologic assessment was performed 3 and 7 days after the procedure. Technical success was achieved in nine of 10 rabbits in each group. One death occurred in group B. Complications included pneumothorax (group A, n = 4; group B, n = 4), abscess (group A, n = 1; group B, n = 1), and thoracic wall burn (group A, n = 4). No significant differences were demonstrated in attenuation increase (P = 0.73), dimensions (P = 0.28, 0.86, 0.06, respectively, comparing D1-D3) and volume (P = 0.17). At histopathology, ablation zones were similar, with septal necrosis, edema, hemorrhage, and peripheral lymphocytic infiltrate. Complete thrombosis of more than 90% of vessels up to 2 mm in diameter was depicted at the periphery of the ablation zone in group A specimens. In group B specimens, complete thrombosis was depicted in 20% of vessels. Feasibility and safety of MW and RF ablation are similar in a lung rabbit model. MW ablation produces a greater damage to peripheral small vessels inducing thrombosis.

  1. Toward carbon-nanotube-based theranostic agents for microwave detection and treatment of breast cancer: enhanced dielectric and heating response of tissue-mimicking materials.

    PubMed

    Mashal, Alireza; Sitharaman, Balaji; Li, Xu; Avti, Pramod K; Sahakian, Alan V; Booske, John H; Hagness, Susan C

    2010-08-01

    The experimental results reported in this paper suggest that single-walled carbon nanotubes (SWCNTs) have the potential to enhance dielectric contrast between malignant and normal tissue for microwave detection of breast cancer and facilitate selective heating of malignant tissue for microwave hyperthermia treatment of breast cancer. In this study, we constructed tissue-mimicking materials with varying concentrations of SWCNTs and characterized their dielectric properties and heating response. At SWCNT concentrations of less than 0.5% by weight, we observed significant increases in the relative permittivity and effective conductivity. In microwave heating experiments, we observed significantly greater temperature increases in mixtures containing SWCNTs. These temperature increases scaled linearly with the effective conductivity of the mixtures. This work is a first step towards the development of functionalized, tumor-targeting SWCNTs as theranostic (integrated therapeutic and diagnostic) agents for microwave breast cancer detection and treatment.

  2. Rapid sample preparation for determination of iron in tissue by closed-vessel digestion and microwave energy.

    PubMed

    Van Wyck, D B; Schifman, R B; Stivelman, J C; Ruiz, J; Martin, D

    1988-06-01

    We developed a rapid acid-digestion method for preparing tissue samples for iron determination. Specimens were digested in nitric acid and hydrogen peroxide under high temperature and pressure in closed Teflon vessels, with microwave energy. Analysis for iron in 25- to 250-mg portions of digested bovine liver powder (National Bureau of Standards Certified Reference Material no. 1577a) showed excellent linearity ([predicted] = 1.007[actual] - 0.166 micrograms per sample) and analytical recovery (98%). Precision (CV) was 5.4% when iron content was 10 micrograms per sample. Assaying split samples of mouse tissues, we found a close correlation between iron concentrations obtained with closed vs open vessels ([closed] = 0.878[open] + 68 micrograms/g, r = 0.994, range 400-4600 micrograms/g dry weight). In contrast to time-consuming conventional procedures for tissue dissolution, closed-vessel digestion with microwave energy dramatically shortens time for tissue preparation, minimizes use of caustic acid, reduces risk of sample loss or contamination, and yields accurate and reproducible results.

  3. Optimization of microwave-assisted extraction for six inorganic and organic arsenic species in chicken tissues using response surface methodology.

    PubMed

    Zhang, Wenfeng; Hu, Yuanan; Cheng, Hefa

    2015-09-01

    Response surface methodology was applied to optimize the parameters for microwave-assisted extraction of six major inorganic and organic arsenic species (As(III), As(V), dimethyl arsenic acid, monomethyl arsenic acid, p-arsanilic acid, and roxarsone) from chicken tissues, followed by detection using a high-performance liquid chromatography with inductively coupled mass spectrometry detection method, which allows the simultaneous analysis of both inorganic and organic arsenic species in the extract in a single run. Effects of extraction medium, solution pH, liquid-to-solid ratio, and the temperature and time of microwave-assisted extraction on the extraction of the targeted arsenic species were studied. The optimum microwave-assisted extraction conditions were: 100 mg of chicken tissue, extracted by 5 mL of 22% v/v methanol, 90 mmol/L (NH4 )2 HPO4 , and 0.07% v/v trifluoroacetic acid (with pH adjusted to 10.0 by ammonium hydroxide solution), ramping for 10 min to 71°C, and holding for 11 min. The method has good extraction performance for total arsenic in the spiked and nonspiked chicken tissues (104.0 ± 13.8% and 91.6 ± 7.8%, respectively), except for the ones with arsenic contents close to the quantitation limits. Limits of quantitation (S/N = 10) for As(III), As(V), dimethyl arsenic acid, monomethyl arsenic acid, p-arsanilic acid, and roxarsone in chicken tissues using this method were 0.012, 0.058, 0.039, 0.061, 0.102, and 0.240 mg/kg (dry weight), respectively.

  4. Effects of antigen retrieval by microwave heating in formalin-fixed tissue sections on a broad panel of antibodies.

    PubMed

    von Wasielewski, R; Werner, M; Nolte, M; Wilkens, L; Georgii, A

    1994-09-01

    Formaldehyde fixation of biopsy specimens for routine purposes has often been held responsible for the poor reproducibility of immunohistochemical studies. Recently, antigen retrieval (AGR) using microwave irradiation was described as a potential tool to enhance immunostaining. A comparison of conventional staining and staining after microwave heating was performed for 52 markers, using tissues fixed in formaldehyde for 24 h, 1 to 6 weeks and 3 years respectively, as well as consultant case material. After adequate duration of fixation (24 h), only a few markers (17%) showed better results after AGR, but this percentage was increased to 50% when tissues were fixed for longer periods. Maximal enhancement was obtained in the group of consultant cases (58% of tested markers demonstrated better staining results), in which the period of fixation and tissue processing was unknown. To achieve reliable enhancement with AGR, continuous heating (100 degrees C) should not be shorter than 20 min. In conclusion, AGR may become the most important tool to simplify and equalize immunohistochemical techniques, if critically evaluated.

  5. Normal Coagulation

    DTIC Science & Technology

    2014-09-04

    protein E deficiency exhibit an increased atherosclerotic burden.112 These observations suggest a role for TFPI in pro- tection from atherosclerosis and...Clin Invest 103:475–482, 1999. 112. Westrick RJ, et al: Deficiency of tissue factor pathway inhibitor pro- motes atherosclerosis and thrombosis in...system. Ann N Y Acad Sci 936:226–236, 2001. 223. Hansson GK: Inflammation, atherosclerosis , and coronary artery disease. N Engl J Med 352:1685–1695

  6. Microwave dispersion and absorption in tissues: molecular mechanisms. Final report, 1 January 1978-28 February 1986

    SciTech Connect

    Foster, K.R.

    1987-12-10

    The authors measured the dielectric properties of materials (tissues, aqueous protein solutions, microemulsions, macroscopic suspensions) from 0.1-18 GHz. These properties are determined over this frequency range by the dielectric properties of water and by ionic effects. Analysis of the data shows that the dielectric properties of the suspending water differ from those of the pure liquid, presumably due to interfacial effects. Similar effects are seen in diverse transport properties and even in nonaqueous systems. The results suggest that water within a couple of monolayers from surfaces have motional correlation times that are tenfold or so longer than those of the bulk liquid. The authors suggest that this motional restriction is a physical effect due to the presence of relatively immobile surfaces, rather than from chemically specific binding. This study has led to an improved understanding of the mechanisms of absorption of microwave energy in tissues, and shown the usefulness of comparative studies of transport processes in complex suspensions.

  7. Micro-quantity tissue digestion for metal measurements by use of a microwave acid-digestion bomb.

    PubMed

    Nicholson, J R; Savory, M G; Savory, J; Wills, M R

    1989-03-01

    We describe a simple and convenient method for processing small amounts of tissue samples for trace-metal measurements by atomic absorption spectrometry, by use of a modified Parr microwave digestion bomb. Digestion proceeds rapidly (less than or equal to 90 s) in a sealed Teflon-lined vessel that eliminates contamination or loss from volatilization. Small quantities of tissue (5-100 mg dry weight) are digested in high-purity nitric acid, yielding concentrations of analyte that can be measured directly without further sample manipulation. We analyzed National Institute of Standards and Technology bovine liver Standard Reference Material to verify the accuracy of the technique. We assessed the applicability of the technique to analysis for aluminum in bone by comparison with a dry ashing procedure.

  8. Helical antenna arrays for interstitial microwave thermal therapy for prostate cancer: tissue phantom testing and simulations for treatment

    NASA Astrophysics Data System (ADS)

    Sherar, Michael D.; Gladman, Aviv S.; Davidson, Sean R. H.; Trachtenberg, John; Gertner, Mark R.

    2001-07-01

    Interstitial microwave therapy is an experimental treatment for prostate cancer. The objective of this work was to measure the power deposition (specific absorption rate, SAR) patterns of helical microwave antennae both individually and in array patterns that would be useful for clinical treatment protocols. Commercial helical antenna 3D SAR patterns were measured in muscle equivalent phantoms using a thermographic technique. Two array patterns were tested: a `square' and a `crescent' array, both surrounding the urethra. To assess the feasibility of pre-treatment planning, the measured SAR patterns were input to a treatment planning computer simulation program based on a series of trans-rectal ultrasound images from a prostate cancer patient. The simulation solved the Pennes linear bioheat heat transfer equation in prostate tissue, with the aim of achieving a target of 55 °C at the prostate periphery while not allowing normal surrounding tissues (bladder, urethra, rectum) to rise above 42 °C. These criteria could not be met with the square array but they could be met with the crescent array, provided that the prostate was first dissected away from the rectum. This can be done with a procedure such as `hydrodissection', where sterile saline is injected to separate the prostate and rectum. The results of these SAR measurements and heat transfer simulations indicate that arrays of helical antennae could be used for safe and effective thermal therapy for prostate cancer.

  9. Microfluidics and Coagulation Biology

    PubMed Central

    Colace, Thomas V.; Tormoen, Garth W.

    2014-01-01

    The study of blood ex vivo can occur in closed or open systems, with or without flow. Microfluidic devices facilitate measurements of platelet function, coagulation biology, cellular biorheology, adhesion dynamics, pharmacology, and clinical diagnostics. An experimental session can accommodate 100s to 1000s of unique clotting events. Using microfluidics, thrombotic events can be studied on defined surfaces of biopolymers, matrix proteins, and tissue factor under constant flow rate or constant pressure drop conditions. Distinct shear rates can be created on a device with a single perfusion pump. Microfluidic devices facilitated the determination of intraluminal thrombus permeability and the discovery that platelet contractility can be activated by a sudden decrease in flow. Microfluidics are ideal for multicolor imaging of platelets, fibrin, and phosphatidylserine and provide a human blood analog to the mouse injury models. Overall, microfluidic advances offer many opportunities for research, drug testing under relevant hemodynamic conditions, and clinical diagnostics. PMID:23642241

  10. Application of microwave-assisted micro-solid-phase extraction for determination of parabens in human ovarian cancer tissues.

    PubMed

    Sajid, Muhammad; Basheer, Chanbasha; Narasimhan, Kothandaraman; Choolani, Mahesh; Lee, Hian Kee

    2015-09-01

    Parabens (alkyl esters of p-hydroxybenzoic acid) are widely used as preservatives in food, cosmetics and pharmaceutical products. However, weak estrogenicity of some parabens has been reported in several studies, which provided the impetus for this work. Here, a simple and efficient analytical method for quantifying parabens in cancer tissues has been developed. This technique involves the simultaneous use of microwave-assisted solvent extraction (MASE) and micro-solid phase extraction (μ-SPE), in tandem with high performance liquid chromatography (HPLC/UV) analysis for the determination of parabens. The pollutants studied included four parabens (methyl, ethyl, propyl and butyl parabens). Optimization of the experimental parameters for MASE and μ-SPE was performed. Good relative standard deviation (%RSD) ranged from 0.09 to 2.81% and high enrichment factors (27-314) were obtained. Coefficients of determination (r(2)) up to 0.9962 were obtained across a concentration range of 5.0-200ngg(-1). The method detection limits for parabens ranged from 0.005 to 0.0244ngg(-1). The procedure was initially tested on prawn samples to demonstrate its feasibility on a complex biological matrix. Preliminary studies on human ovarian cancer (OC) tissues showed presence of parabens. Higher levels of parabens were detected in malignant ovarian tumor tissues compared to benign tumor tissue samples.

  11. Evolution of the complex permittivity of biological tissue at microwaves ranges: correlation study with burn depth.

    PubMed

    Matthieu, Brusson; Jerome, Rossignol; Stephane, Binczak; Gabriel, Laurent

    2014-01-01

    The evolution of the muscle tissue's complex permittivity represents a growing interest in terms of characterization in medicine and biology. The influence of a burned part on the permittivity is not very developed. In this work, an estimation of the complex permittivity of biological tissues is performed as a function of the depth of burn tissues. The sensor, an open-ended coaxial probe, is placed directly against each sample. The evolution of the complex permittivity is studied for two measurements conditions (in the air and in a physiological solution). A correlation study is attempted with the depth of burn tissue.

  12. Determination of cadmium by electrothermal atomic absorption spectrometry after microwave-assisted digestion of animal tissues and sewage sludges.

    PubMed

    Chakraborty, R; Das, A K; Cervera, M L; De La Guardia, M

    1996-04-01

    The determination of cadmium in different sample types has been carried out by electrothermal atomization atomic absorption spectrometry with D(2)-background correction using a unpyrocoated graphite tube, after pressurized microwave-assisted digestion. Five chemical modifiers [(NH(4))(2)HPO(4), Pd(NO)(3))(2), Ni(NO(3))(2), thiourea and Triton X-100] have been assayed and nickel nitrate has been found to be most effective for an accurate determination of cadmium in mussel tissue, pig kidney and sewage sludge. The characteristic mass of the method is of the order of 1 pg and the limit of detection is lower than 0.1 ng/ml.

  13. Laser optoacoustic technique for real-time measurement of thermal damage in tissues

    NASA Astrophysics Data System (ADS)

    Esenaliev, Rinat O.; Larina, Irina V.; Larin, Kirill V.; Motamedi, Massoud; Karabutov, Alexander A.; Oraevsky, Alexander A.

    1999-05-01

    Optoacoustic monitoring of thermally-induced damage in tissues in real time is proposed as a mean for controlling the extent of tissue coagulation in human organs, such as liver, prostate, myocardium, breast, and brain. This technique can potentially provide fast and accurate feedback information during tumor thermal coagulation by interstitial delivery of laser, ultrasonic, radiofrequency, and microwave radiation or conductive and convective heating. Amplitude and temporal characteristics of optoacoustic signals are dependent on optical and thermophysical properties of tissues. Changes in tissue optical properties during coagulation can be detected by measuring and analyzing the amplitude and temporal characteristics of the optoacoustic signals. We performed studies on optoacoustic monitoring of coagulation by CW Nd:YAG laser interstitial irradiation and conductive heating. Q-switched Nd:YAG laser pulses were used as a probing radiation to obtain optoacoustic pressure profiles and images. Our preliminary studies suggest that the laser optoacoustic technique is capable of detecting thermally-induced changes in optical properties of liver, myocardium, and prostate. The major merits of the laser optoacoustic monitoring of tissue coagulation include high contrast provided by changes in tissue optical properties, capability to perform real-time measurements, and high spatial resolution.

  14. Microwave distillation-solid phase adsorbent trapping device for the determination of off-flavors, geosmin and methylisoborneol, in catfish tissue below their rejection levels

    SciTech Connect

    Conte, E.D.; Shen, C.Y.; Miller, D.W.; Perschbacher, P.W.

    1996-08-01

    Described is a rapid microwave-mediated steam distillation device for determining two predominant off-flavor compounds, geosmin and methylisoborneol, in catfish tissue. A microwave on-time of 10 min is needed to efficiently remove these off-flavor compounds from the sample matrix and trap them on a solid phase adsorbent. A minimal amount of organic solvent is used to elute the trapped compounds. The extract is then analyzed by gas chromatography with ion trap detection in the selective ion storage mode. Detection limits in the sub-parts-per-billion range are obtained with this method. 11 refs., 5 figs., 1 tab.

  15. Stable Microwave Radiometry System for Long Term Monitoring of Deep Tissue Temperature

    PubMed Central

    Stauffer, Paul R.; Rodriques, Dario B.; Salahi, Sara; Topsakal, Erdem; Oliveira, Tiago R.; Prakash, Aniruddh; D'Isidoro, Fabio; Reudink, Douglas; Snow, Brent W.; Maccarini, Paolo F.

    2013-01-01

    Background There are numerous clinical applications for non-invasive monitoring of deep tissue temperature. We present the design and experimental performance of a miniature radiometric thermometry system for measuring volume average temperature of tissue regions located up to 5cm deep in the body. Methods We constructed a miniature sensor consisting of EMI-shielded log spiral microstrip antenna with high gain on-axis and integrated high-sensitivity 1.35GHz total power radiometer with 500 MHz bandwidth. We tested performance of the radiometry system in both simulated and experimental multilayer phantom models of several intended clinical measurement sites: i) brown adipose tissue (BAT) depots within 2cm of the skin surface, ii) 3–5cm deep kidney, and iii) human brain underlying intact scalp and skull. The physical models included layers of circulating tissue-mimicking liquids controlled at different temperatures to characterize our ability to quantify small changes in target temperature at depth under normothermic surface tissues. Results We report SAR patterns that characterize the sense region of a 2.6cm diameter receive antenna, and radiometric power measurements as a function of deep tissue temperature that quantify radiometer sensitivity. The data demonstrate: i) our ability to accurately track temperature rise in realistic tissue targets such as urine refluxed from prewarmed bladder into kidney, and 10°C drop in brain temperature underlying normothermic scalp and skull, and ii) long term accuracy and stability of ∓0.4°C over 4.5 hours as needed for monitoring core body temperature over extended surgery or monitoring effects of brown fat metabolism over an extended sleep/wake cycle. Conclusions A non-invasive sensor consisting of 2.6cm diameter receive antenna and integral 1.35GHz total power radiometer has demonstrated sufficient sensitivity to track clinically significant changes in temperature of deep tissue targets underlying normothermic surface

  16. Stable microwave radiometry system for long term monitoring of deep tissue temperature

    NASA Astrophysics Data System (ADS)

    Stauffer, Paul R.; Rodriques, Dario B.; Salahi, Sara; Topsakal, Erdem; Oliveira, Tiago R.; Prakash, Aniruddh; D'Isidoro, Fabio; Reudink, Douglas; Snow, Brent W.; Maccarini, Paolo F.

    2013-02-01

    Background: There are numerous clinical applications for non-invasive monitoring of deep tissue temperature. We present the design and experimental performance of a miniature radiometric thermometry system for measuring volume average temperature of tissue regions located up to 5cm deep in the body. Methods: We constructed a miniature sensor consisting of EMI-shielded log spiral microstrip antenna with high gain onaxis and integrated high-sensitivity 1.35GHz total power radiometer with 500 MHz bandwidth. We tested performance of the radiometry system in both simulated and experimental multilayer phantom models of several intended clinical measurement sites: i) brown adipose tissue (BAT) depots within 2cm of the skin surface, ii) 3-5cm deep kidney, and iii) human brain underlying intact scalp and skull. The physical models included layers of circulating tissue-mimicking liquids controlled at different temperatures to characterize our ability to quantify small changes in target temperature at depth under normothermic surface tissues. Results: We report SAR patterns that characterize the sense region of a 2.6cm diameter receive antenna, and radiometric power measurements as a function of deep tissue temperature that quantify radiometer sensitivity. The data demonstrate: i) our ability to accurately track temperature rise in realistic tissue targets such as urine refluxed from prewarmed bladder into kidney, and 10°C drop in brain temperature underlying normothermic scalp and skull, and ii) long term accuracy and stability of +0.4°C over 4.5 hours as needed for monitoring core body temperature over extended surgery or monitoring effects of brown fat metabolism over an extended sleep/wake cycle. Conclusions: A non-invasive sensor consisting of 2.6cm diameter receive antenna and integral 1.35GHz total power radiometer has demonstrated sufficient sensitivity to track clinically significant changes in temperature of deep tissue targets underlying normothermic surface

  17. Microwave-assisted fibrous decoration of mPE surface utilizing Aloe vera extract for tissue engineering applications.

    PubMed

    Balaji, Arunpandian; Jaganathan, Saravana Kumar; Supriyanto, Eko; Muhamad, Ida Idayu; Khudzari, Ahmad Zahran Md

    2015-01-01

    Developing multifaceted, biocompatible, artificial implants for tissue engineering is a growing field of research. In recent times, several works have been reported about the utilization of biomolecules in combination with synthetic materials to achieve this process. Accordingly, in this study, the ability of an extract obtained from Aloe vera, a commonly used medicinal plant in influencing the biocompatibility of artificial material, is scrutinized using metallocene polyethylene (mPE). The process of coating dense fibrous Aloe vera extract on the surface of mPE was carried out using microwaves. Then, several physicochemical and blood compatibility characterization experiments were performed to disclose the effects of corresponding surface modification. The Fourier transform infrared spectrum showed characteristic vibrations of several active constituents available in Aloe vera and exhibited peak shifts at far infrared regions due to aloe-based mineral deposition. Meanwhile, the contact angle analysis demonstrated a drastic increase in wettability of coated samples, which confirmed the presence of active components on glazed mPE surface. Moreover, the bio-mimic structure of Aloe vera fibers and the influence of microwaves in enhancing the coating characteristics were also meticulously displayed through scanning electron microscopy micrographs and Hirox 3D images. The existence of nanoscale roughness was interpreted through high-resolution profiles obtained from atomic force microscopy. And the extent of variations in irregularities was delineated by measuring average roughness. Aloe vera-induced enrichment in the hemocompatible properties of mPE was established by carrying out in vitro tests such as activated partial thromboplastin time, prothrombin time, platelet adhesion, and hemolysis assay. In conclusion, the Aloe vera-glazed mPE substrate was inferred to attain desirable properties required for multifaceted biomedical implants.

  18. Numerical 3D modeling of heat transfer in human tissues for microwave radiometry monitoring of brown fat metabolism

    NASA Astrophysics Data System (ADS)

    Rodrigues, Dario B.; Maccarini, Paolo F.; Salahi, Sara; Colebeck, Erin; Topsakal, Erdem; Pereira, Pedro J. S.; Limão-Vieira, Paulo; Stauffer, Paul R.

    2013-02-01

    Background: Brown adipose tissue (BAT) plays an important role in whole body metabolism and could potentially mediate weight gain and insulin sensitivity. Although some imaging techniques allow BAT detection, there are currently no viable methods for continuous acquisition of BAT energy expenditure. We present a non-invasive technique for long term monitoring of BAT metabolism using microwave radiometry. Methods: A multilayer 3D computational model was created in HFSSTM with 1.5 mm skin, 3-10 mm subcutaneous fat, 200 mm muscle and a BAT region (2-6 cm3) located between fat and muscle. Based on this model, a log-spiral antenna was designed and optimized to maximize reception of thermal emissions from the target (BAT). The power absorption patterns calculated in HFSSTM were combined with simulated thermal distributions computed in COMSOL® to predict radiometric signal measured from an ultra-low-noise microwave radiometer. The power received by the antenna was characterized as a function of different levels of BAT metabolism under cold and noradrenergic stimulation. Results: The optimized frequency band was 1.5-2.2 GHz, with averaged antenna efficiency of 19%. The simulated power received by the radiometric antenna increased 2-9 mdBm (noradrenergic stimulus) and 4-15 mdBm (cold stimulus) corresponding to increased 15-fold BAT metabolism. Conclusions: Results demonstrated the ability to detect thermal radiation from small volumes (2-6 cm3) of BAT located up to 12 mm deep and to monitor small changes (0.5 °C) in BAT metabolism. As such, the developed miniature radiometric antenna sensor appears suitable for non-invasive long term monitoring of BAT metabolism.

  19. Microwave-assisted fibrous decoration of mPE surface utilizing Aloe vera extract for tissue engineering applications

    PubMed Central

    Balaji, Arunpandian; Jaganathan, Saravana Kumar; Supriyanto, Eko; Muhamad, Ida Idayu; Khudzari, Ahmad Zahran Md

    2015-01-01

    Developing multifaceted, biocompatible, artificial implants for tissue engineering is a growing field of research. In recent times, several works have been reported about the utilization of biomolecules in combination with synthetic materials to achieve this process. Accordingly, in this study, the ability of an extract obtained from Aloe vera, a commonly used medicinal plant in influencing the biocompatibility of artificial material, is scrutinized using metallocene polyethylene (mPE). The process of coating dense fibrous Aloe vera extract on the surface of mPE was carried out using microwaves. Then, several physicochemical and blood compatibility characterization experiments were performed to disclose the effects of corresponding surface modification. The Fourier transform infrared spectrum showed characteristic vibrations of several active constituents available in Aloe vera and exhibited peak shifts at far infrared regions due to aloe-based mineral deposition. Meanwhile, the contact angle analysis demonstrated a drastic increase in wettability of coated samples, which confirmed the presence of active components on glazed mPE surface. Moreover, the bio-mimic structure of Aloe vera fibers and the influence of microwaves in enhancing the coating characteristics were also meticulously displayed through scanning electron microscopy micrographs and Hirox 3D images. The existence of nanoscale roughness was interpreted through high-resolution profiles obtained from atomic force microscopy. And the extent of variations in irregularities was delineated by measuring average roughness. Aloe vera-induced enrichment in the hemocompatible properties of mPE was established by carrying out in vitro tests such as activated partial thromboplastin time, prothrombin time, platelet adhesion, and hemolysis assay. In conclusion, the Aloe vera-glazed mPE substrate was inferred to attain desirable properties required for multifaceted biomedical implants. PMID:26425089

  20. [Determination of trace element silver in animal serum, tissues and organs by microwave digestion-ICP-MS].

    PubMed

    Yuan, Jun-Jie; Xie, You-Zhuan; Han, Chen; Sun, Wei; Zhang, Kai; Zhao, Jie; Lu, Xiao; Lu, Jian-Xi; Ren, Wei

    2014-09-01

    Nowadays, the silver is widely used in the biological field and its biological safety catches great attention. It is important to know the distribution of silver ions within the biological organism and the toxic threshold concentration in the tissue. Therefore, a highly sensitive method for measurement of trace amount of silver ion in the medical biological samples is needed. With its high sensitivity for detection of metal ions, inductively coupled plasma mass spectrometry (ICP-MS) method is well suited for quantification of trace amount of silver ion in such samples, but method development is still in its infancy. Consequently, a simple and convenient method for determination of trace amount of silver in the animal serum, tissues or organs was developed, in which the samples were subjected to the microwave digestion, followed by the ICP-MS analysis. To begin with, the samples of serum, muscle, bone marrow, bone, heart, liver, spleen, and kidney were sequently processed in 5 mL of HNO3 and 2 mL of H2O2 solution. Then the samples were completely digested by microwave with the power of 2 000 watts. The temperature was raised gradually by 3-step program. Moreover, the data achieved were reproducible and the method was time saving and especially for large amounts of sample processing. Then the digested solutions were diluted to constant volume. Finally, the concentration of 107Ag in the samples was analyzed by the method of ICP-MS under the optimized conditions. Element yttrium (Y) was used as the internal standard to compensate for matrix suppression effect and improve the accuracy of measurement. For one thing, the analytical results showed that the detection limit of the trace element 107Ag was 0.98 μg · kg(-1), and furthermore, the correlation coefficient of standard curve was 0.999 9. For another thing, the recovery rate of the silver element ranged from 98% to 107%, which was calculated according to measured quantity before adding standard, adding standard and

  1. The Interface between Inflammation and Coagulation in Cardiovascular Disease

    PubMed Central

    Demetz, Gabriele; Ott, Ilka

    2012-01-01

    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

  2. Dust coagulation in ISM

    NASA Technical Reports Server (NTRS)

    Chokshi, Arati; Tielens, Alexander G. G. M.; Hollenbach, David

    1989-01-01

    Coagulation is an important mechanism in the growth of interstellar and interplanetary dust particles. The microphysics of the coagulation process was theoretically analyzed as a function of the physical properties of the coagulating grains, i.e., their size, relative velocities, temperature, elastic properties, and the van der Waal interaction. Numerical calculations of collisions between linear chains provide the wave energy in individual particles and the spectrum of the mechanical vibrations set up in colliding particles. Sticking probabilities are then calculated using simple estimates for elastic deformation energies and for the attenuation of the wave energy due to absorption and scattering processes.

  3. [Coagulation disorders in cirrhosis].

    PubMed

    Téllez-Avila, Felix I; Chávez-Tapia, Norberto C; Torre-Delgadillo, Aldo

    2007-01-01

    The liver plays a central role in the clotting process. In this organ are sintetizated the major part of the coagulation factors. Historically, was considered that alteration in liver function causes important bleeding disorders. However, actual evidence is not in agreement with this asseveration. Decreased synthesis of clotting and inhibitor factors, decrease clearance of activated factors, quantitative and qualitative platelet defects, hyperfibrinolysis and intravascular coagulation are some of the defects observed in liver diseases. Thrombotic events, even if rare in cirrhotic patients, occur manly in the portal and mesenteric veins. The aim of the present work is to review the present evidence in coagulation disorders and liver disease.

  4. The Mechanisms of Coagulation.

    ERIC Educational Resources Information Center

    Kurtz, Richard; Jesty, Jolyon

    1994-01-01

    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)

  5. Coagulation Factors Test

    MedlinePlus

    ... this page helpful? Also known as: Factor Assays; Blood Clotting Factors; Clotting Factors [or by the individual factor ... person has enough coagulation activity to control the blood clotting process. It is used by healthcare practitioners to ...

  6. [Diagnostic of blood coagulation].

    PubMed

    Barthels, M

    2008-12-01

    A survey is given on the peculiar characteristics of laboratory methods for analyzing the blood coagulation system with special regard to the preanalytical, analytical and postanalytical phase. Routinely used methods are described.

  7. [Acquired coagulant factor inhibitors].

    PubMed

    Nogami, Keiji

    2015-02-01

    Acquired coagulation factor inhibitors are an autoimmune disease causing bleeding symptoms due to decreases in the corresponding factor (s) which result from the appearance of autoantibodies against coagulation factors (inhibitor). This disease is quite different from congenital coagulation factor deficiencies based on genetic abnormalities. In recent years, cases with this disease have been increasing, and most have anti-factor VIII autoantibodies. The breakdown of the immune control mechanism is speculated to cause this disease since it is common in the elderly, but the pathology and pathogenesis are presently unclear. We herein describe the pathology and pathogenesis of factor VIII and factor V inhibitors. Characterization of these inhibitors leads to further analysis of the coagulation process and the activation mechanisms of clotting factors. In the future, with the development of new clotting examination method (s), we anticipate that further novel findings will be obtained in this field through inhibitor analysis. In addition, detailed elucidation of the coagulation inhibitory mechanism possibly leading to hemostatic treatment strategies for acquired coagulation factor disorders will be developed.

  8. Practical evaluations on heating characteristics of thin microwave antenna for intracavitary thermal therapy.

    PubMed

    Saito, Kazuyuki; Tsubouchi, Kousuke; Takahashi, Masaharu; Ito, Koichi

    2010-01-01

    Microwave thermal therapy is one of the modalities for cancer treatment. There are several schemes of microwave heating. The authors have been studying thin coaxial antenna for intracavitary microwave heating aiming at the treatment of bile duct carcinoma. Up to now, the heating characteristics of the antenna are investigated by numerical simulation and experiment for finding a possibility of the treatment. In this study, in order to consider practical situations of the treatment, heating characteristics of the antenna inserted into a metallic stent is evaluated by numerical simulations. Moreover, the relation between coagulation size of the tissue and the radiation power from the antenna is investigated experimentally. It must be considered, when the input power of the antenna is high (around several tens of watts). From these investigations, some useful results for practical treatments were found.

  9. Genetic engineering and coagulation factors.

    PubMed

    Fass, D N; Toole, J J

    1985-06-01

    It is unfortunate that we cannot report, in the area of coagulation, advances that have been seen in related fields such as thrombolytic therapy. The reported progress (Gold et al, 1984; Van de Werf et al, 1984) with human recombinant tissue plasminogen activator (Pennica et al, 1983) augers well for the application of recombinant technology to the problems faced by patients with coagulation defects. While plasminogen activator is being assessed in an acute therapeutic setting, its use signals a beginning of the application of the technology to abnormalities of the haemostatic mechanism. Chronic administration of coagulation factors for prophylaxis and replacement therapy would appear to be just one more step down the pathway illuminated by the biochemists, microbiologists and cell biologists who have preceded the clinicians in this promising area. There is no record of the use of genetically engineered materials in the treatment of coagulation defects, primarily because the body of knowledge and refined techniques have only recently been acquired. For this reason we have had to project developments in other areas onto the problems that exist for the haemostatically compromised patient. In describing the potential usefulness of these technologies, it is difficult to ascertain where the logical projection, from a fully investigated model system, diverges from flights of imaginative fancy. Cloning projects considered overly ambitious and grandiose at the beginning of this decade are already accomplished feats. The feasibility of gene therapy in the mammalian system has been demonstrated, and trade publications now discuss governmental approval for investigative use of this procedure in 1985. Panels of physicians, scientists and even politicians now seriously contemplate and promulgate views and regulations pertaining to the efficacy and ethics of the use of genetic engineering in the treatment of human disease. The haemophilias will certainly be among the first

  10. Partial microwave-assisted wet digestion of animal tissue using a baby-bottle sterilizer for analyte determination by inductively coupled plasma optical emission spectrometry

    NASA Astrophysics Data System (ADS)

    Matos, Wladiana O.; Menezes, Eveline A.; Gonzalez, Mário H.; Costa, Letícia M.; Trevizan, Lilian C.; Nogueira, Ana Rita A.

    2009-06-01

    A procedure for partial digestion of bovine tissue is proposed using polytetrafluoroethylene (PTFE) micro-vessels inside a baby-bottle sterilizer under microwave radiation for multi-element determination by inductively coupled plasma optical emission spectrometry (ICP OES). Samples were directly weighed in laboratory-made polytetrafluoroethylene vessels. Nitric acid and hydrogen peroxide were added to the uncovered vessels, which were positioned inside the baby-bottle sterilizer, containing 500 mL of water. The hydrogen peroxide volume was fixed at 100 µL. The system was placed in a domestic microwave oven and partial digestion was carried out for the determination of Ca, Cu, Fe, Mg, Mn and Zn by inductively coupled plasma optical emission spectrometry. The single-vessel approach was used in the entire procedure, to minimize contamination in trace analysis. Better recoveries and lower residual carbon content (RCC) levels were obtained under the conditions established through a 2 4-1 fractional factorial design: 650 W microwave power, 7 min digestion time, 50 µL nitric acid and 50 mg sample mass. The digestion efficiency was ascertained according to the residual carbon content determined by inductively coupled plasma optical emission spectrometry. The accuracy of the proposed procedure was checked against two certified reference materials.

  11. Numerical study of the effect of blood vessel on the microwave ablation shape.

    PubMed

    Nie, Xiaohui; Nan, Qun; Guo, Xuemei; Tian, Zhen

    2015-01-01

    The existence of large blood vessels seriously impacts the results of microwave ablation on heat transfer of surrounding tissue, and the research of influences about large blood vessels could be essential and significant. The temperature distribution in the tissue was analyzed with a microwave heating source by finite element method. The model, where the blood vessel is parallel to antenna, has different distances from antenna to blood vessel. As distance was greater than 20mm, the effect of blood vessel that was parallel to antenna was ignored and the ablation area was elliptical-like. When distance was less than 10mm, the part of asymmetrical coagulated area was on the right side of blood vessel. Therefore, the temperature contour by different conditions could provide numerical references, which is whether to block blood vessel or not, to achieve the aim of guiding the clinical practice, according to the locations of tumor and blood vessel.

  12. Finite-element analysis and in vitro experiments of placement configurations using triple antennas in microwave hepatic ablation.

    PubMed

    Phasukkit, Pattarapong; Tungjitkusolmun, Supan; Sangworasil, Manas

    2009-11-01

    This study presents analyses of triple-antenna configurations and designs for microwave (MW) hepatic ablation using 3-D finite-element (FE) analyses verified by in vitro experiments. Treatment of hepatic cancer often requires removal or destruction of large volume lesions. Using multiple antennas offers a potential solution for creating ablation zones with larger dimensions, as well as varied geometrical shapes. We performed both 3-D FE analyses and in vitro experiments using three identical open-tip MW antennas simultaneously, placing them in three types of configurations-"linear array," "triangular," and "T-shaped" arrangements. We compared coagulation volumes created, as well as temperature distribution characteristics, from the three-antenna arrangements after power delivery of 50 W for 60 s. We also performed additional tests using nonidentical antennas (open tip, slot, and slot with insulating jacket) for the three configurations. The results illustrate that arranging antennas in the "T-shaped" pattern destroyed more unwanted tissues than those found when using "linear array" and "triangular" arrangements, with maximum coagulation width and depth of 46 and 81 mm, respectively, and coagulation volume of 30.7 cm(3) . In addition, using nonidentical triple antennas caused variations in coagulation zone characteristics, and thus, the technique could be applied to treatment situations where nonsymmetric coagulation zones are required.

  13. Coagulation alterations due to local fibrinolytic therapy with recombinant tissue-type plasminogen activator (rt-PA) in patients with peripheral arterial occlusive disease

    SciTech Connect

    Rauber, Klaus; Heidinger, Kathrin S.; Kemkes-Matthes, Bettina

    1997-05-15

    Purpose. To determine the systemic effects of local fibrinolytic therapy with low-dose recombinant tissue-type plasminogen activator (rt-PA). Methods. Ten patients received intrathrombal infusion of 20 mg rt-PA and heparin for local thrombolysis and had subsequent percutaneous transluminal angioplasty (PTA). Eight controls underwent PTA and received heparin alone. We measured t-PA, D-Dimer, and fibrinogen levels before, directly after, and 20, 40, and 60 min and 24 hr after therapy. Results. In the thrombolysis group the t-PA level peaked immediately after infusion and then declined within 1 hr. D-Dimer increased and remained elevated, whereas in the control group only t-PA levels increased, and only after 24 hr. Fibrinogen remained within the normal range in both groups. Eight of ten patients in the thrombolysis group and seven of eight with PTA had clinical improvement after the procedure. Conclusions. The increase in D-Dimer in the rt-PA group indicates a good local fibrinolytic effect. The fact that fibrinogen levels remained unchanged indicates that there is a lack of systemic fibrinogenolysis.

  14. Tailor-made biopolymers porous scaffold fabrication for tissue engineering: application of radiant energy in the form of microwave under vacuum.

    PubMed

    Jaya, S; Durance, T D

    2008-01-01

    Many methods are available for developing three-dimensional porous scaffolds using various polymeric materials for tissue-engineering applications. Each has its own advantages and disadvantages. Some of the available methods and their limitations were discussed briefly. This paper focuses on the scope of novel technology called radiant energy application under vacuum for the fabrication of three-dimensional porous scaffolds for tissue engineering applications. Radiant energy application in the form of microwave under vacuum has been shown to develop and maintain the porous structure in fruits and vegetables after dehydration, which produced the microstructure similar to the freeze dried materials. Same principle of applying radiant energy under vacuum was used on the biopolymeric gels to create tailor-made, porous scaffolds for biomedical purposes. It has many advantages over the other existing methods of scaffold fabrication. This paper also reviews the scaffolds design recently fabricated by the authors using radiant energy under vacuum.

  15. DNA and RNA isolated from tissues processed by microwave-accelerated apparatus MFX-800-3 are suitable for subsequent PCR and Q-RT-PCR amplification.

    PubMed

    Bödör, Csaba; Schmidt, Otto; Csernus, Balázs; Rajnai, Hajnalka; Szende, Béla

    2007-01-01

    Over the past decade, methods of molecular biology have appeared in diagnostic pathology and are routinely applied on formalin-fixed, paraffin-embedded histological samples, processed via conventional embedding methods. Due to its reagent- and cost-effectiveness, embedding techniques that utilize microwave acceleration in one or more steps of histoprocessing are increasingly used by numerous laboratories. The demand arises that tissues processed this way should also be suitable for the requirements of molecular pathology. In this study, both conventionally embedded and MFX-800-3 machine-processed tissue samples from the same source were used for isolation of DNA and RNA and for performing PCR and real-time PCR. PCR amplification of the beta-globin gene, as well as the real-time PCR amplification of the ABL mRNA was successful in all cases. Our conclusion is that samples processed by the vacuum assisted automatic microwave histoprocessor MFX-800-3 are perfectly applicable for DNA and RNA isolation and provide appropriate templates for further PCR and realtime PCR studies.

  16. Asthma and coagulation.

    PubMed

    de Boer, J Daan; Majoor, Christof J; van 't Veer, Cornelis; Bel, Elisabeth H D; van der Poll, Tom

    2012-04-05

    Asthma is a chronic airway disease characterized by paroxysmal airflow obstruction evoked by irritative stimuli on a background of allergic lung inflammation. Currently, there is no cure for asthma, only symptomatic treatment. In recent years, our understanding of the involvement of coagulation and anticoagulant pathways, the fibrinolytic system, and platelets in the pathophysiology of asthma has increased considerably. Asthma is associated with a procoagulant state in the bronchoalveolar space, further aggravated by impaired local activities of the anticoagulant protein C system and fibrinolysis. Protease-activated receptors have been implicated as the molecular link between coagulation and allergic inflammation in asthma. This review summarizes current knowledge of the impact of the disturbed hemostatic balance in the lungs on asthma severity and manifestations and identifies new possible targets for asthma treatment.

  17. Coagulation in Liver Disease.

    PubMed

    Hoffman, Maureane

    2015-07-01

    The liver plays a key role in hemostasis as the site of synthesis of many of the proteins involved in the coagulation, antithrombotic and fibrinolytic systems that interact to both establish hemostasis, and preventing thrombosis. The common laboratory tests, prothrombin time (PT) and activated partial thromboplastin time (aPTT), evolved from studies of plasma clotting in test tubes. Such studies laid the basis for the coagulation cascade model of hemostasis. However, thought has evolved to place a greater emphasis on the active roles of cells in localizing and regulating hemostasis. The PT and aPTT do not reflect the roles of cellular elements in hemostasis, nor do they reflect the crucial roles of antithrombotic and fibrinolytic systems. Thus, though the PT may indeed reflect the synthetic capacity of the liver, it does not accurately reflect the risk of bleeding or thrombosis in patients with liver failure.

  18. Microwave ablation of the atrioventricular junction in open-chest dogs

    SciTech Connect

    Lin, J.C.; Wang, Y.J.; Beckman, K.J.; Hariman, R.J.; Bharati, S.; Lev, M.

    1995-06-01

    The use of microwave energy for ablation of the atrioventricular (AV) junction was examined in open-chest dogs. Usually a specially designed microwave catheter and a 2,450 MHz generator, microwave energy was delivered to the AV junction according to one of two protocols. In protocol 1, increasing amounts of energy were delivered until irreversible AV block occurred. In protocol 2, only two applications of energy were used, one at low energy and the other at an energy found to be high enough to cause irreversible AV block. Each dog received between one and six applications of microwave energy. The amount of energy delivered per application ranged from 25.6 to 311.4 J. No AV block was seen at 59.4 {+-} 28.3 J. Reversible AV block was seen with an energy of 120.6 {+-} 58 J. Irreversible AV block was seen at 188.1 {+-} 75.9 J. Irreversible AV block could be achieved in each animal. There was no difference in the energy required to cause irreversible AV block between the two protocols. The tissue temperature measured near the tip of the microwave catheter was correlated with both the amount of energy delivered and the extent of AV block caused. Histologic examination demonstrated coagulation necrosis of the conduction system. Microwave energy is a feasible alternative energy source for myocardial ablation. Since tissue damage is due exclusively to heating and the resulting rise in temperature can be measured, microwave energy may have advantages over currently existing energy sources in terms of both titrating delivered energy and monitoring the extent of tissue destruction.

  19. Electrosurgical device for both mechanical cutting and coagulation of bleeding

    DOEpatents

    Doss, J.D.; McCabe, C.W.

    1985-02-08

    Bipolar electrical coagulation of tissue using radiofrequency energy is combined with the functions of conventional surgical pressure tissue cutting instruments without significant modification thereof in a single instrument with the result that a surgeon can perform both procedures without having to redirect his attention from the area of the surgery. 4 figs.

  20. Electrosurgical device for both mechanical cutting and coagulation of bleeding

    DOEpatents

    Doss, James D.; McCabe, Charles W.

    1987-01-01

    Bipolar electrical coagulation of tissue using radio-frequency energy is combined with the functions of conventional surgical pressure tissue cutting instruments without significant modification thereof in a single instrument with the result that a surgeon can perform both procedures without having to redirect his attention from the area of the surgery.

  1. A short contemporary history of disseminated intravascular coagulation.

    PubMed

    Levi, Marcel; van der Poll, Tom

    2014-11-01

    Disseminated intravascular coagulation (DIC) is a syndrome characterized by systemic intravascular activation of coagulation, leading to a widespread deposition of fibrin in the circulation. There is ample experimental and pathological evidence that the fibrin deposition contributes to multiple organ failure. The massive and ongoing activation of coagulation may result in depletion of platelets and coagulation factors, which may cause bleeding (consumption coagulopathy). The syndrome of DIC is well known in the medical literature for centuries, although a more precise description of the underlying mechanisms had to await the 20th century. Initial ideas on a role of the contact activation system as the primary trigger for the systemic activation of coagulation as well as a presumed hyperfibrinolytic response in DIC have been found to be misconceptions. Experimental and clinical evidence now indicate that the initiation of coagulation in DIC is caused by tissue factor expression, which in combination with downregulated physiological anticoagulant pathways and impaired fibrinolysis leads to widespread fibrin deposition. In addition, an extensive bidirectional interaction between coagulation and inflammation may further contribute to the pathogenesis of DIC.

  2. Implementation of a microwave-assisted tissue-processing system and an automated embedding system for breast needle core biopsy samples: morphology, immunohistochemistry, and FISH evaluation.

    PubMed

    Pegolo, Enrico; Pandolfi, Maura; Di Loreto, Carla

    2013-07-01

    A platform composed of a microwave (MW)-assisted tissue-processing system and an automated embedding system has been recently introduced in pathology laboratories. Needle core biopsy (NCB) is an established, highly accurate method for diagnosing breast lesions and for providing important pathologic, predictive, and prognostic information such as biomarker expression in case of breast carcinoma. The aim of this study was to evaluate whether breast NCBs processed with the MW-assisted tissue-processing system and automatically embedded show good-quality histology preparations and whether they are suitable for the assessment of estrogen receptor (ER), progesterone receptor (PR), Ki-67, and HER2 in breast carcinoma. A series of 233 consecutive breast NCBs processed by both conventional and MW-assisted tissue-processing systems was included in this study. The histomorphologic and immunohistochemical quality, as well as the results of the evaluation of the biomarkers, were compared-the conventional processing method being the gold standard for comparison. The quality of hematoxylin-eosin and immunohistochemical tissue sections provided by the new system is comparable to that obtained after the conventional processing method. Moreover, in breast carcinomas, a perfect agreement between the paired tissues when evaluating ER and PR status (Cohen κ = 1) and a very good agreement when evaluating Ki-67 (κ = 0.91) and HER2 (κ = 0.93) have been found. In conclusion, applying strict criteria in tissue-handling steps, breast NCB can be processed and automatically embedded with these platforms. The diagnosability and the evaluation of the main prognostic and predictive biomarkers have been proved to be reliable.

  3. Quantification of Paraquat, MPTP, and MPP+ in brain tissue using microwave-assisted solvent extraction (MASE) and high performance liquid chromatography-mass spectrometry

    PubMed Central

    Winnik, Bozena; Barr, Dana B.; Thiruchelvam, Mona; Montesano, M. Angela; Richfield, Eric K.; Buckley, Brian

    2014-01-01

    Animal models, consistent with the hypothesis of direct interaction of paraquat (PQ) and 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) with specific areas of the central nervous system have been developed to study Parkinson’s disease (PD) in mice. These models have necessitated the creation of an analytical method for unambiguous identification and quantitation of PQ and structurally similar MPTP and 1-Methyl-4-phenylpyridinium ion (MPP+) in brain tissue. A method for determination of these compounds was developed using microwave-assisted solvent extraction (MASE) and liquid chromatography-mass spectrometry. Extraction solvent and microwave conditions such as power and time were optimized to produce recoveries of 90% for PQ 78% for MPTP and 97% for its metabolite MPP+. The chromatographic separation was performed on a C8, column and detection was carried out using an ion trap as an analyzer with electrospray ionization. Mass spectrometer parameters such as heated capillary temperature, spray voltage, capillary voltage and others were also optimized for each analyte. Analysis was done in Selective Ion Monitoring (SIM) mode using 186 m/z for PQ, m/z 174 for MPTP, and m/z 170 for MPP+. The method detection limit for paraquat in matrix was 100 pg and 40 pg for MPTP and 20 pg MPP+. PMID:19618168

  4. Examination of the effect of dose-death interval on detection of meperidine exposure in decomposed skeletal tissues using microwave-assisted extraction.

    PubMed

    Watterson, James H; Desrosiers, Nathalie A

    2011-04-15

    The effect of dose-death interval and tissue distribution on the detection of meperidine in selected skeletal tissues was examined using a rapid microwave-assisted extraction (MAE) methodology. Rats (n=14) were dosed with 0 (n=2) or 30 mg/kg (n=12) meperidine (i.p.). Drug-positive rats were sacrificed with CO(2) after 20, 30, 90 and 150 min (n=3 per group). Heart blood was collected immediately after death. Tibiae were excised and frozen for further analysis. The remaining carcasses were allowed to decompose outside in secured cages to the point of complete skeletonization in a rural Northern Ontario location during the late summer months. Vertebrae and pelvi were collected for each animal. Tibial marrow was homogenized in 3 mL PB6 (phosphate buffer, 0.1M, pH 6). Fresh tibiae, and decomposed vertebrae and pelvi were cleaned in PB8.5 (phosphate buffer, 0.1M, pH 8.5) and sonicated to remove remaining soft tissue. Samples of dried, ground bone (0.5-1g) suspended in 2 mL PB6 were then irradiated in a domestic microwave oven (1100 W) at atmospheric pressure for 15 min. Samples of vertebral bone (1g) were also extracted by passive incubation in methanol (3 mL, 50°C, 72 h). All supernatants then underwent solid-phase extraction and analysis by GC/MS, using electron impact ionization in the Selected Ion Monitoring (SIM) mode. Mean GC/MS responses for each tissue type were negatively correlated with dose-death interval, with correlation coefficients ranging from -0.32 to -0.87. Analysis of variance showed dose-death interval to be a main effect (p<0.05) with respect to GC/MS response for blood, marrow, tibial epiphyses prepared by MAE, and vertebral bone prepared by passive extraction, but not for tibial diaphyses, pelvi or vertebrae prepared by MAE. Overall, MAE is advantageous as a rapid extraction tool for screening purposes in skeletal tissues, but assignment of significance to quantitative expressions of skeletal drug concentrations is complex and should be approached

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

    PubMed

    Cugno, Massimo; Gualtierotti, Roberta; Tedeschi, Alberto; Meroni, Pier Luigi

    2014-01-01

    Autoantibodies may develop against coagulation factors altering their function or promoting their rapid clearance. In non-congenitally deficient patients, they are usually in association with autoimmune diseases, malignancies, pregnancy or advanced age. The possible development of coagulation factor autoantibodies should be considered when a patient presents with bleeding symptoms without any prior bleeding diathesis. The most common disorder associated with coagulation factor autoantibodies is acquired factor VIII deficiency, which is characterized by hemorrhages involving soft tissues, muscles and skin; hemarthroses are less frequent than in the inherited form. Acquired deficiencies of von Willebrand factor and factor XIII due to autoantibodies are emerging conditions. Autoantibodies to the other coagulation factors may be associated with a wide spectrum of clinical manifestations ranging from minimal or no bleeding to life-threatening conditions. The diagnostic approach begins with global coagulation tests: prothrombin time (PT) and activated partial thromboplastin time (aPTT). In case of prolonged times, mixing studies (typically using normal plasma in a 1:1 proportion) should be performed. Specific factor and inhibitor assays, assessment of lupus anticoagulant and eventually enzyme immunoassays for specific anti-factor antibodies complete the evaluation. A prompt diagnosis of specific coagulation factor inhibitors is mandatory for starting an appropriate treatment aimed at overcoming the deficient factor, in case of bleeding, and, if possible, at the suppression of the autoantibody's production.

  6. Microwave Ovens

    MedlinePlus

    ... Emitting Products Radiation-Emitting Products and Procedures Home, Business, and Entertainment Products Microwave ... for Consumers Laws, Regulations & Standards Industry Guidance Other Resources Description Microwave ...

  7. Spatial localization of bacteria controls coagulation of human blood by 'quorum acting'.

    PubMed

    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

    2008-12-01

    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.

  8. Thermophoretically modified aerosol brownian coagulation.

    PubMed

    Arias-Zugasti, Manuel; Rosner, Daniel E

    2011-08-01

    A theory of aerosol coagulation rates resulting from continuum-regime brownian coagulation in the presence of size-dependent particle thermophoresis is developed and explored here. We are motivated by a wide variety of applications in which particle brownian coagulation occurs in a nonisothermal gas where differential thermophoretic drift contributes to, but does not dominate, the encounter frequency between suspended spherical particles (e.g., mist droplets) of different sizes. We employ a Smoluchowski-like population-balance to demonstrate the relative roles of brownian diffusion and thermophoresis in shaping the short and long time (asymptotic or "coagulation-aged") mist-droplet size distribution (DSD) function. To carry out these combined-mechanism DSD-evolution calculations we developed a rational "coupled" coagulation rate constant (allowing for simultaneous brownian diffusion and relative thermophoretic drift) rather than simply adding the relevant individual coagulation "kernels." Dimensionless criteria are provided to facilitate precluding other coagulation mechanisms not considered here (such as simultaneous sedimentation or Marangoni-flow-induced mist-droplet phoresis) and potential complications not included in the present model [as finite-rate coalescence, initial departures from the continuum (Stokes drag-) limit, and even dense (nonideal) vapor effects].

  9. Thermophoretically modified aerosol Brownian coagulation

    NASA Astrophysics Data System (ADS)

    Arias-Zugasti, Manuel; Rosner, Daniel E.

    2011-08-01

    A theory of aerosol coagulation rates resulting from continuum-regime Brownian coagulation in the presence of size-dependent particle thermophoresis is developed and explored here. We are motivated by a wide variety of applications in which particle Brownian coagulation occurs in a nonisothermal gas where differential thermophoretic drift contributes to, but does not dominate, the encounter frequency between suspended spherical particles (e.g., mist droplets) of different sizes. We employ a Smoluchowski-like population-balance to demonstrate the relative roles of Brownian diffusion and thermophoresis in shaping the short and long time (asymptotic or “coagulation-aged”) mist-droplet size distribution (DSD) function. To carry out these combined-mechanism DSD-evolution calculations we developed a rational “coupled” coagulation rate constant (allowing for simultaneous Brownian diffusion and relative thermophoretic drift) rather than simply adding the relevant individual coagulation “kernels.” Dimensionless criteria are provided to facilitate precluding other coagulation mechanisms not considered here (such as simultaneous sedimentation or Marangoni-flow-induced mist-droplet phoresis) and potential complications not included in the present model [as finite-rate coalescence, initial departures from the continuum (Stokes drag-) limit, and even dense (nonideal) vapor effects].

  10. Thymoquinone Modulates Blood Coagulation in Vitro via Its Effects on Inflammatory and Coagulation Pathways

    PubMed Central

    Muralidharan-Chari, Vandhana; Kim, Jaehan; Abuawad, Ahlam; Naeem, Mubeena; Cui, Huadong; Mousa, Shaker A.

    2016-01-01

    Thymoquinone (THQ) is a major component of black seeds. Given that both THQ and black seeds exhibit anti-cancer and anti-inflammatory activities, we hypothesized that THQ will affect cancer-associated thrombosis (CAT), which is primarily triggered by tissue factor (TF) and inflammation. The effect of both black seed-extracted and purchased (“pure”) THQ on normal blood coagulation was tested with in vitro thromboelastography (TEG) and activated partial thromboplastin time (aPTT) coagulation assays. The effect of pure THQ on CAT was tested with aPTT assay using pancreatic cancer cell lines that are either positive or negative for TF, and with TEG assay using lipopolysaccharide as an inflammatory trigger. Additionally, the direct effect of THQ on the inactivation of factors IIa and Xa was assessed. Since TNF-α facilitates crosstalk between inflammation and thrombosis by triggering the NF-κB pathway, we tested THQ’s ability to interfere with this communication with a luciferase assay. Both extracted and pure THQ had minimal effects on normal blood coagulation. Pure THQ reversed CAT initiated by both TF and inflammation to basal levels (p < 0.001). Mechanistically, while THQ had minimal to no effect on factor IIa and Xa inactivation, it strongly reduced the effects of TNF-α on NF-κB elements (p < 0.001). THQ has a minimal effect on basal coagulation and can reverse CAT in vitro, possibly by interfering with the crosstalk between inflammation and coagulation. This study suggests the utility of THQ as a preventative anticoagulant and/or as a supplement to existing chemotherapies and anticoagulant therapies. PMID:27043539

  11. [Proteins influencing the blood coagulation].

    PubMed

    Alberio, Lorenzo

    2011-11-01

    This review describes some natural proteins, which can be employed, either as factor concentrates derived from human plasma or as recombinant drug, to modulate the coagulation system. I will address some biochemical characteristics and the physiological role of von Willebrand factor, the coagulation factors of the extrinsic and intrinsic pathways, and the physiological anticoagulant protein C. In addition, I will detail the pharmacological compounds, which are available for influencing or substituting the coagulation proteins: desmopressin (DDAVP), single coagulation factor concentrates, prothrombin complex concentrates, and protein C concentrate. In particular, I will address some treatment topics of general medical interest, such as the treatment of massive bleeding, the correction of the coagulopathy induced by vitamin K-antagonists in patients with cerebral haemorrhage, and of the coagulopathy of meningococcemia. Finally, I will describe some properties and practical clinical applications of the recombinant anticoagulans lepirudin and bivalirudin, which are derived from hirudin, the natural anticoagulant of the medical leech.

  12. Disorders of coagulation in pregnancy.

    PubMed

    Katz, D; Beilin, Y

    2015-12-01

    The process of haemostasis is complex and is further complicated in the parturient because of the physiological changes of pregnancy. Understanding these changes and the impact that they have on the safety profile of the anaesthetic options for labour and delivery is crucial to any anaesthetist caring for the parturient. This article analyses current theories on coagulation and reviews the physiological changes to coagulation that occur during pregnancy and the best methods with which to evaluate coagulation. Finally, we examine some of the more common disorders of coagulation that occur during pregnancy, including von Willebrand disease, common factor deficiencies, platelet disorders, the parturient on anticoagulants, and the more rare acute fatty liver of pregnancy, with a focus on their implications for neuraxial anaesthesia.

  13. Whole blood coagulation analyzers.

    PubMed

    1997-08-01

    Whole blood Coagulation analyzers (WBCAs) are widely used point-of-care (POC) testing devices found primarily in cardiothoracic surgical suites and cardia catheterization laboratories. Most of these devices can perform a number of coagulation tests that provide information about a patient's blood clotting status. Clinicians use the results of the WBCA tests, which are available minutes after applying a blood sample, primarily to monitor the effectiveness of heparin therapy--an anticoagulation therapy used during cardiopulmonary bypass (CPB) surgery, angioplasty, hemodialysis, and other clinical procedures. In this study we evaluated five WBCAs from four suppliers. Our testing focused on the applications for which WBCAs are primarily used: Monitoring moderate to high heparin levels, as would be required, for example, during CPB are angioplasty. For this function, WCBAs are typically used to perform an activated clotting time (ACT) test or, as one supplier refers to its test, a heparin management test (HMT). All models included in this study offered an ACT test or an HMT. Monitoring low heparin levels, as would be required, for example,during hemodialysis. For this function, WBCAs would normally be used to perform either a low-range ACT (LACT) test or a whole blood activated partial thromboplastin time (WBAPTT) test. Most of the evaluated units could perform at least one of these tests; one unit did not offer either test and was therefore not rated for this application. We rated and ranked each evaluated model separately for each of these two applications. In addition, we provided a combined rating and ranking that considers the units' appropriateness for performing both application. We based our conclusions on a unit's performance and humans factor design, as determined by our testing, and on its five-year life-cycle cost, as determined by our net present value (NPV) analysis. While we rated all evaluated units acceptable for each appropriate category, we did

  14. Microwave Ablation Using Four-Tine Antenna: Effects of Blood Flow Velocity, Vessel Location, and Total Displacement on Porous Hepatic Cancer Tissue

    PubMed Central

    Chaichanyut, Montree

    2016-01-01

    This research is concerned with microwave ablation analyses using a 2.45 GHz four-tine (4T) antenna for hepatic cancer tissue. In the study, three-dimensional finite-element models were utilized to examine the tissue temperature distributions during and after MW ablation. A preliminary study was first carried out with regard to the specific absorption rates along the 4T antenna insertion depths and the temperature distributions inside the solid and porous liver models with either 3 cm-in-diameter tumor or 5 cm-in-diameter tumor. Based on the preliminary results, the porous models were further examined for the effect of varying blood flow velocities (0–200 cm/s) with a 1 cm-in-diameter blood vessel next to the antenna and also for the effect of vessel-antenna locations (0, 0.8, and 1.3 cm) with a constant blood flow velocity of 16.7 cm/s. All scenarios were simulated under temperature-controlled mode (90°C). The findings revealed that the blood flow velocity and vessel location influence the ablation effectiveness and that increased blood flow inhibits heat transfer to the vessel wall. At the nearest and farthest vessel-antenna locations (0 and 1.3 cm), approximately 90.3% and 99.55% of the cancer cells were eradicated except for the areas adjacent to the vessel. In addition, total tissue thermal displacement is 5.9 mm which is 6.59% of the total length of the overall model. PMID:27642364

  15. Microwave Ablation Using Four-Tine Antenna: Effects of Blood Flow Velocity, Vessel Location, and Total Displacement on Porous Hepatic Cancer Tissue.

    PubMed

    Chaichanyut, Montree; Tungjitkusolmun, Supan

    2016-01-01

    This research is concerned with microwave ablation analyses using a 2.45 GHz four-tine (4T) antenna for hepatic cancer tissue. In the study, three-dimensional finite-element models were utilized to examine the tissue temperature distributions during and after MW ablation. A preliminary study was first carried out with regard to the specific absorption rates along the 4T antenna insertion depths and the temperature distributions inside the solid and porous liver models with either 3 cm-in-diameter tumor or 5 cm-in-diameter tumor. Based on the preliminary results, the porous models were further examined for the effect of varying blood flow velocities (0-200 cm/s) with a 1 cm-in-diameter blood vessel next to the antenna and also for the effect of vessel-antenna locations (0, 0.8, and 1.3 cm) with a constant blood flow velocity of 16.7 cm/s. All scenarios were simulated under temperature-controlled mode (90°C). The findings revealed that the blood flow velocity and vessel location influence the ablation effectiveness and that increased blood flow inhibits heat transfer to the vessel wall. At the nearest and farthest vessel-antenna locations (0 and 1.3 cm), approximately 90.3% and 99.55% of the cancer cells were eradicated except for the areas adjacent to the vessel. In addition, total tissue thermal displacement is 5.9 mm which is 6.59% of the total length of the overall model.

  16. EXTRINSIC COAGULATION BLOCKADE ATTENUATES LUNG INJURY AND PROINFLAMMATORY CYTOKINE RELEASE AFTER INTRATRACHEAL LIPOPOLYSACCHARIDE

    EPA Science Inventory

    Initiation of coagulation by tissue factor (TF) is a potentially powerful regulator of local inflammatory responses. We hypothesized that blockade of TF-factor VIIa (FVIIa) complex would decrease lung inflammation and proinflammatory cytokine release after tracheal instillation o...

  17. Demonstration of the extrinsic coagulation pathway in teleostei: Identification of zebrafish coagulation factor VII

    PubMed Central

    Sheehan, John; Templer, Michael; Gregory, Michael; Hanumanthaiah, Ravikumar; Troyer, Dean; Phan, Thao; Thankavel, Bharath; Jagadeeswaran, Pudur

    2001-01-01

    It is not known whether the mammalian mechanism of coagulation initiation is conserved in fish. Identification of factor VII is critical in providing evidence for such a mechanism. A cDNA was cloned from a zebrafish (teleost) library that predicted a protein with sequence similarity to human factor VII. Factor VII was shown to be present in zebrafish blood and liver by Western blot analysis and immunohistochemistry. Immunodepletion of factor VII from zebrafish plasma selectively inhibited thromboplastin-triggered thrombin generation. Heterologous expression of zebrafish factor VII demonstrated a secreted protein (50 kDa) that reconstituted thromboplastin-triggered thrombin generation in immunodepleted zebrafish plasma. These results suggest conservation of the extrinsic coagulation pathway between zebrafish and humans and add credence to the zebrafish as a model for mammalian hemostasis. The structure of zebrafish factor VIIa predicted by homology modeling was consistent with the overall three-dimensional structure of human factor VIIa. However, amino acid disparities were found in the epidermal growth factor-2/serine protease regions that are present in the human tissue factor–factor VIIa contact surface, suggesting a structural basis for the species specificity of this interaction. In addition, zebrafish factor VII demonstrates that the Gla-EGF-EGF-SP domain structure, which is common to coagulation factors VII, IX, X, and protein C, was present before the radiation of the teleosts from the tetrapods. Identification of zebrafish factor VII significantly narrows the evolutionary window for development of the vertebrate coagulation cascade and provides insight into the structural basis for species specificity in the tissue factor–factor VIIa interaction. PMID:11459993

  18. Comparison of coagulation performance and floc properties of a novel zirconium-glycine complex coagulant with traditional coagulants.

    PubMed

    Zhang, Zhilin; Wu, Chunde; Wu, Yue; Hu, Caixia

    2014-05-01

    A new inorganic-organic hybrid material zirconium-glycine complex (ZGC) was firstly used as a coagulant in a coagulation process to treat Pearl River raw water. Its coagulation performance was compared with commonly used aluminum (Al) coagulants such as aluminum sulfate (Al2(SO4)3) and polyaluminum chloride (PAC), in terms of water quality parameters and floc properties. ZGC coagulation achieved higher removal of turbidity (93.8%) than other traditional coagulants. Charge neutralization was proven to act as a dominant mechanism during ZGC coagulation. The aggregated flocs with ZGC showed the fastest growth rate and good recovery ability compared with the other coagulants and achieved the largest floc size within 5 min. The ZGC coagulant can decrease the hydraulic retention time and increase removal efficiency.

  19. Freeze drying reduces the extractability of organochlorine pesticides in fish muscle tissue by microwave-assisted method.

    PubMed

    Zhang, Yanyan; Lin, Nan; Su, Shu; Shen, Guofeng; Chen, Yuanchen; Yang, Chunli; Li, Wei; Shen, Huizhong; Huang, Ye; Chen, Han; Wang, Xilong; Liu, Wenxin; Tao, Shu

    2014-08-01

    Samples of animal origin are usually dried before solvent extraction for analysis of organic contaminants. The freeze drying technique is preferred for hydrophobic organic compounds in practice. In this study, it was shown that the concentration of organochlorine pesticides (OCPs) extracted from fish muscle tissue significantly decreased after the samples were freeze dried. And the reason for this reduced extractability seemed to be the resistance of OCPs associated with freeze-dried muscle protein to solvent extraction. The extractability can be recovered by adding water prior to extraction. It suggests that the dietary exposure risk of OCPs from fish might be underestimated if freeze-dried samples are used.

  20. Principles of dielectric blood coagulometry as a comprehensive coagulation test.

    PubMed

    Hayashi, Yoshihito; Brun, Marc-Aurèle; Machida, Kenzo; Nagasawa, Masayuki

    2015-10-06

    Dielectric blood coagulometry (DBCM) is intended to support hemostasis management by providing comprehensive information on blood coagulation from automated, time-dependent measurements of whole blood dielectric spectra. We discuss the relationship between the series of blood coagulation reactions, especially the aggregation and deformation of erythrocytes, and the dielectric response with the help of clot structure electron microscope observations. Dielectric response to the spontaneous coagulation after recalcification presented three distinct phases that correspond to (P1) rouleau formation before the onset of clotting, (P2) erythrocyte aggregation and reconstitution of aggregates accompanying early fibrin formation, and (P3) erythrocyte shape transformation and/or structure changes within aggregates after the stable fibrin network is formed and platelet contraction occurs. Disappearance of the second phase was observed upon addition of tissue factor and ellagic acid for activation of extrinsic and intrinsic pathways, respectively, which is attributable to accelerated thrombin generation. A series of control experiments revealed that the amplitude and/or quickness of dielectric response reflect platelet function, fibrin polymerization, fibrinolysis activity, and heparin activity. Therefore, DBCM sensitively measures blood coagulation via erythrocytes aggregation and shape changes and their impact on the dielectric permittivity, making possible the development of the battery of assays needed for comprehensive coagulation testing.

  1. Determination of methylmercury in fish tissue by gas chromatography with microwave-induced plasma atomic emission spectrometry after derivatization with sodium tetraphenylborate.

    PubMed

    Palmieri, H E; Leonel, L V

    2000-03-01

    The detection of methylmercury species (MeHg) in fish tissue was investigated. Samples were digested with KOH-methanol and acidified prior to extraction with methylene chloride. MeHg was back-extracted from the organic phase into water. An aliquot of this aqueous solution (buffered to pH 5) was subjected to derivatization with sodium tetraphenylborate (NaBPh4) and then extracted with toluene. The organic phase containing MePhHg was injected into a gas chromatograph (GC) which is on-line with a microwave-induced plasma atomic emission spectrometer (MIP-AED). The quantification limit was about 0.6 microg/g and 0.1 microg/g of MeHg (as Hg) for 0.08 g of freeze-dried fish powder and 0.5 g of fresh samples, respectively. Two certified reference materials, CRM 464 (tuna fish) from Community Bureau of Reference-BCR and DORM-2 (dogfish muscle) from National Research Council Canada-NRC were selected for checking the accuracy of the method. This methodology was applied to the determination of MeHg in some kinds of fish from the Carmo river with alluvial gold recovery activities ("garimpos") in Mariana, Minas Gerais, Brazil.

  2. Microwave diagnostics of atmospheric plasmas

    NASA Astrophysics Data System (ADS)

    Scott, David

    Plasma treatment of biological tissues has tremendous potential due to the wide range of applications. Most plasmas have gas temperatures which greatly exceed room temperature. These are often utilized in electro-surgery for cutting and coagulating tissue. Another type of plasma, referred to as cold atmospheric plasma, or CAP, is characterized by heavy particle temperatures which are at or near room temperature. Due to this lack of thermal effect, CAP may provide less invasive medical procedures. Additionally, CAP have been demonstrated to be effective at targeting cancer cells while minimizing damage to the surrounding tissue. A recently fabricated Microwave Electron Density Device (MEDD) utilizes microwave scattering on small atmospheric plasmas to determine the electron plasma density. The MEDD can be utilized on plasmas which range from a fraction of a millimeter to several centimeters at atmospheric pressure when traditional methods cannot be applied. Microwave interferometry fails due to the small size of the plasma relative to the microwave wavelength which leads to diffraction and negligible phase change; electrostatic probes introduce very strong perturbation and are associated with difficulties of application in strongly-collisional atmospheric conditions; and laser Thomson scattering is not sensitive enough to measure plasma densities less than 1012 cm-3. The first part of this dissertation provides an overview of two types of small atmospheric plasma objects namely CAPs and plasmas utilized in the electro-surgery. It then goes on to describe the fabrication, testing and calibration of the MEDD facility. The second part of this dissertation is focused on the application of the MEDD and other diagnostic techniques to both plasma objects. A series of plasma images that illustrate the temporal evolution of a discharge created by an argon electrosurgical device operating in the coagulation mode and its behavior was analyzed. The discharge of the argon

  3. [Coagulation disorders in the intensive care station].

    PubMed

    Hart, C; Spannagl, M

    2014-05-01

    Coagulation disorders are frequently encountered in the intensive care unit (ICU) and are challenging due to a variety of potential etiologies. Critically ill patients with coagulation abnormalities may present with an increased risk of bleeding, show coagulation activation resulting in thromboembolism, or have no specific symptoms. Hemostatic abnormalities observed in ICU patients range from isolated thrombocytopenia or prolonged global clotting tests to complex and life-threatening coagulation defects. Successful management of coagulation disorders requires prompt and accurate identification of the underlying cause. This review describes the most frequently occurring diagnoses found in intensive care patients with thrombocytopenia and coagulation test abnormalities and summarizes appropriate diagnostic interventions and current approaches to differential diagnosis.

  4. Advances of Coagulation Factor XIII

    PubMed Central

    Shi, Da-Yu; Wang, Shu-Jie

    2017-01-01

    Objective: To provide a comprehensive literature review on roles of coagulation factor XIII (FXIII) in coagulation, wound healing, neoplasm, bone metabolism, and pregnancy. Data Sources: All articles in PubMed with key words Coagulation factor XIII, wound, leukemia, tumor, bone, and pregnancy with published date from 2001 to 2016 were included in the study. Frequently cited publications before 2000 were also included. Study Selection: We reviewed the role of FXIII in biologic processes as documented in clinical, animal, and in vitro studies. Results: FXIII, a member of the transglutaminase (TG) family, plays key roles in various biological processes. Besides its well-known function in coagulation, the cross-linking of small molecules catalyzed by FXIII has been found in studies to help promote wound healing, improve bone metabolism, and prevent miscarriages. The study has also shown that FXIII concentration level differs in the blood of patients with leukemia and solid tumors and offers promises as a diagnostic indicator. Conclusions: FXIII has many more biologic functions besides being known as coagulation factor. The TG activity of FXIII contributes to several processes, including wound healing, bone extracellular matrix stabilization, and the interaction between embryo and decidua of uterus. Further research is needed to elucidate the link between FXIII and leukemia and solid tumors. PMID:28091415

  5. Coagulation assays and anticoagulant monitoring.

    PubMed

    Funk, Dorothy M Adcock

    2012-01-01

    Anticoagulant therapy, including conventional agents and a variety of new oral, fast-acting drugs, is prescribed for millions of patients annually. Each anticoagulant varies in its effect on routine and specialty coagulation assays and each drug may require distinct laboratory assay(s) to measure drug concentration or activity. This review provides an overview of the assorted assays that can measure anticoagulant drug concentration or activity and includes key assay interferences. The effect of these conventional and new anticoagulant agents on specialty coagulation assays used to evaluate for bleeding or clotting disorders, and whether this impact is physiological or factitious, is included. Also provided is a short review of superwarfarin poisoning and features distinguishing this from warfarin overdose. Knowledge of clinically significant pearls and pitfalls pertinent to coagulation assays in relation to anticoagulant therapy are important to optimize patient care.

  6. The Inflammatory Actions of Coagulant and Fibrinolytic Proteases in Disease

    PubMed Central

    Schuliga, Michael

    2015-01-01

    Aside from their role in hemostasis, coagulant and fibrinolytic proteases are important mediators of inflammation in diseases such as asthma, atherosclerosis, rheumatoid arthritis, and cancer. The blood circulating zymogens of these proteases enter damaged tissue as a consequence of vascular leak or rupture to become activated and contribute to extravascular coagulation or fibrinolysis. The coagulants, factor Xa (FXa), factor VIIa (FVIIa), tissue factor, and thrombin, also evoke cell-mediated actions on structural cells (e.g., fibroblasts and smooth muscle cells) or inflammatory cells (e.g., macrophages) via the proteolytic activation of protease-activated receptors (PARs). Plasmin, the principle enzymatic mediator of fibrinolysis, also forms toll-like receptor-4 (TLR-4) activating fibrin degradation products (FDPs) and can release latent-matrix bound growth factors such as transforming growth factor-β (TGF-β). Furthermore, the proteases that convert plasminogen into plasmin (e.g., urokinase plasminogen activator) evoke plasmin-independent proinflammatory actions involving coreceptor activation. Selectively targeting the receptor-mediated actions of hemostatic proteases is a strategy that may be used to treat inflammatory disease without the bleeding complications of conventional anticoagulant therapies. The mechanisms by which proteases of the coagulant and fibrinolytic systems contribute to extravascular inflammation in disease will be considered in this review. PMID:25878399

  7. Depinning as a coagulation process

    NASA Astrophysics Data System (ADS)

    İşeri, M.; Kaspar, D.; Mungan, M.

    2016-08-01

    We consider a one-dimensional model that describes the depinning of an elastic string of particles in a strongly pinning, phase-disordered periodic environment under a slowly increasing force. The evolution towards depinning occurs by the triggering of avalanches in regions of activity which are at first isolated, but later grow and merge. For large system sizes the dynamically critical behavior is dominated by the coagulation of these active regions. Our analysis and numerical simulations show that the evolution of the sizes of active regions is well described by a Smoluchowski coagulation equation, allowing us to predict correlation lengths and avalanche sizes in terms of certain moments of the size distribution.

  8. [Coagulation behavior of Al13 species].

    PubMed

    Hu, Cheng-zhi; Liu, Hui-juan; Qu, Jiu-hui

    2006-12-01

    Coagulation behavior of Al13 species was examined in synthetic water with high alkalinity and high humic acid concentration from viewpoint of the transformation of Al hydrolysis products during the coagulation process. The results indicated that coagulation efficiency of Al coagulants positively correlated with the content of Al13 in the coagulation process. Aluminum chloride (AlCl3) was more effective than polyaluminum chloride (PACI) in removing turbidity and dissolved organic matter in the synthetic water because AlCl3 could not only generate Al13 species but also function as pH control agent in the coagulation process. During coagulation process pH control can improve coagulation process through regulating Al speciation, and AlCl3 benefited most from pH control.

  9. Lutein recovery from Chlorella sp. ESP-6 with coagulants.

    PubMed

    Utomo, Rhesa Pramudita; Chang, Yin-Ru; Lee, Duu-Jong; Chang, Jo-Shu

    2013-07-01

    Production of algal lutein included cell cultivation, biomass harvesting, cell wall disruption, and subsequent purification if needed. This work cultivated Chlorella sp. ESP-6 cells in photobioreactor to a biomass content of 1.1 gl(-1) and then the freezing-grinding, ultrasonic treatment (20 and 42kHz) and microwave treatment were used to disrupt the cell walls for recover intracellular lutein. The grinding recovered more lutein than ultrasound or microwave pretreatment. Single coagulation using >30 mgl(-1) chitosan or dual-conditioning using 10 mg l(-1) polyaluminum chloride and 10 mgl(-1) chitosan effectively enhance sedimentation and membrane filtration efficiency of algal suspensions. However, the presence of coagulants lowers the lutein yield from algal biomass in the subsequent 20 kHz ultrasound treatment and purification process. Simulation results revealed affine adsorption of lutein onto chitosan molecules via hydroxyl-amine interaction. The possible drawback by pre-treatment stage should be considered together with the subsequent recovery stage in whole process assessment.

  10. Blood coagulation and the risk of atherothrombosis: a complex relationship.

    PubMed

    Spronk, Henri Mh; van der Voort, Danielle; Ten Cate, Hugo

    2004-12-01

    The principles of Virchov's triad appear to be operational in atherothrombosis or arterial thrombosis: local flow changes and particularly vacular wall damage are the main pathophysiological elements. Furthermore, alterations in arterial blood composition are also involved although the specific role and importance of blood coagulation is an ongoing matter of debate. In this review we provide support for the hypothesis that activated blood coagulation is an essential determinant of the risk of atherothrombotic complications. We distinguish two phases in atherosclerosis: In the first phase, atherosclerosis develops under influence of "classical" risk factors, i.e. both genetic and acquired forces. While fibrinogen/fibrin molecules participate in early plaque lesions, increased activity of systemic coagulation is of no major influence on the risk of arterial thrombosis, except in rare cases where a number of specific procoagulant forces collide. Despite the presence of tissue factor - factor VII complex it is unlikely that all fibrin in the atherosclerotic plaque is the direct result from local clotting activity. The dominant effect of coagulation in this phase is anticoagulant, i.e. thrombin enhances protein C activation through its binding to endothelial thrombomodulin.The second phase is characterized by advancing atherosclerosis, with greater impact of inflammation as indicated by an elevated level of plasma C-reactive protein, the result of increased production influenced by interleukin-6. Inflammation overwhelms protective anticoagulant forces, which in itself may have become less efficient due to down regulation of thrombomodulin and endothelial cell protein C receptor (EPCR) expression. In this phase, the inflammatory drive leads to recurrent induction of tissue factor and assembly of catalytic complexes on aggregated cells and on microparticles, maintaining a certain level of thrombin production and fibrin formation. In advanced atherosclerosis systemic and

  11. Transcatheter Antenna For Microwave Treatment

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James R. (Inventor); Raffoul, George W. (Inventor); Karasack, Vincent G. (Inventor); Pacifico, Antonio (Inventor); Pieper, Carl F. (Inventor)

    2000-01-01

    Method and apparatus are provided for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue to treat ventricular tachycardia and other arrhythmias while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In operation, microwave energy between about 1 Gigahertz and 12 Gigahertz is applied to monopole microwave radiation having a surface wave limiter. A test setup provides physical testing of microwave radiators to determine the temperature profile created in actual heart tissue or ersatz heart tissue. Saline solution pumped over the heart tissue with a peristaltic pump simulates blood flow. Optical temperature sensors disposed at various tissue depths within the heart tissue detect the temperature profile without creating any electromagnetic interference. The method may he used to produce a desired temperature profile in other body tissues reachable by catheter such as tumors and the like.

  12. Microwave Treatment for Cardiac Arrhythmias

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James R. (Inventor); Raffoul, George W. (Inventor); Pacifico, Antonio (Inventor)

    1999-01-01

    Method and apparatus are provided for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue to treat ventricular tachycardia and other arrhythmias while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In operation, microwave energy between about 1 Gigahertz and 12 Gigahertz is applied to monopole microwave radiator having a surface wave limiter. A test setup provides physical testing of microwave radiators to determine the temperature profile created in actual heart tissue or ersatz heart tissue. Saline solution pumped over the heart tissue with a peristaltic pump simulates blood flow. Optical temperature sensors disposed at various tissue depths within the heart tissue detect the temperature profile without creating any electromagnetic interference. The method may be used to produce a desired temperature profile in other body tissues reachable by catheter such as tumors and the like.

  13. Defective thrombus formation in mice lacking coagulation factor XII

    PubMed Central

    Renné, Thomas; Pozgajová, Miroslava; Grüner, Sabine; Schuh, Kai; Pauer, Hans-Ulrich; Burfeind, Peter; Gailani, David; Nieswandt, Bernhard

    2005-01-01

    Blood coagulation is thought to be initiated by plasma protease factor VIIa in complex with the membrane protein tissue factor. In contrast, coagulation factor XII (FXII)–mediated fibrin formation is not believed to play an important role for coagulation in vivo. We used FXII-deficient mice to study the contributions of FXII to thrombus formation in vivo. Intravital fluorescence microscopy and blood flow measurements in three distinct arterial beds revealed a severe defect in the formation and stabilization of platelet-rich occlusive thrombi. Although FXII-deficient mice do not experience spontaneous or excessive injury-related bleeding, they are protected against collagen- and epinephrine-induced thromboembolism. Infusion of human FXII into FXII-null mice restored injury-induced thrombus formation. These unexpected findings change the long-standing concept that the FXII-induced intrinsic coagulation pathway is not important for clotting in vivo. The results establish FXII as essential for thrombus formation, and identify FXII as a novel target for antithrombotic therapy. PMID:16009717

  14. A plasma proteolysis pathway comprising blood coagulation proteases.

    PubMed

    Yang, Lu; Li, Yun; Bhattacharya, Arup; Zhang, Yuesheng

    2016-07-05

    Coagulation factors are essential for hemostasis. Here, we show that these factors also team up to degrade plasma proteins that are unrelated to hemostasis. Prolidase, SRC and amyloid β1-42 (Aβ1-42) are used as probes. Each probe, upon entering the blood circulation, binds and activates factor XII (FXII), triggering the intrinsic and common coagulation cascades, which in turn activate factor VII, a component of the extrinsic coagulation cascade. Activated factor VII (FVIIa) rapidly degrades the circulating probes. Therefore, FXII and FVIIa serve as the sensor/initiator and executioner, respectively, for the proteolysis pathway. Moreover, activation of this pathway by one probe leads to the degradation of all three probes. Significant activation of this pathway follows tissue injury and may also occur in other disorders, e.g., Alzheimer's disease, of which Aβ1-42 is a key driver. However, enoxaparin, a clinically used anticoagulant, inhibits the proteolysis pathway and elevates plasma levels of the probes. Enoxaparin may also mitigate potential impact of activators of the proteolysis pathway on coagulation. Our results suggest that the proteolysis pathway is important for maintaining low levels of various plasma proteins. Our finding that enoxaparin inhibits this pathway provides a means to control it. Inhibition of this pathway may facilitate the development of disease biomarkers and protein therapeutics, e.g., plasma Aβ1-42 as a biomarker of Alzheimer's disease or recombinant human prolidase as an antitumor agent.

  15. Optical coherence tomography-guided laser microsurgery for blood coagulation with continuous-wave laser diode

    NASA Astrophysics Data System (ADS)

    Chang, Feng-Yu; Tsai, Meng-Tsan; Wang, Zu-Yi; Chi, Chun-Kai; Lee, Cheng-Kuang; Yang, Chih-Hsun; Chan, Ming-Che; Lee, Ya-Ju

    2015-11-01

    Blood coagulation is the clotting and subsequent dissolution of the clot following repair to the damaged tissue. However, inducing blood coagulation is difficult for some patients with homeostasis dysfunction or during surgery. In this study, we proposed a method to develop an integrated system that combines optical coherence tomography (OCT) and laser microsurgery for blood coagulation. Also, an algorithm for positioning of the treatment location from OCT images was developed. With OCT scanning, 2D/3D OCT images and angiography of tissue can be obtained simultaneously, enabling to noninvasively reconstruct the morphological and microvascular structures for real-time monitoring of changes in biological tissues during laser microsurgery. Instead of high-cost pulsed lasers, continuous-wave laser diodes (CW-LDs) with the central wavelengths of 450 nm and 532 nm are used for blood coagulation, corresponding to higher absorption coefficients of oxyhemoglobin and deoxyhemoglobin. Experimental results showed that the location of laser exposure can be accurately controlled with the proposed approach of imaging-based feedback positioning. Moreover, blood coagulation can be efficiently induced by CW-LDs and the coagulation process can be monitored in real-time with OCT. This technology enables to potentially provide accurate positioning for laser microsurgery and control the laser exposure to avoid extra damage by real-time OCT imaging.

  16. Optical coherence tomography-guided laser microsurgery for blood coagulation with continuous-wave laser diode.

    PubMed

    Chang, Feng-Yu; Tsai, Meng-Tsan; Wang, Zu-Yi; Chi, Chun-Kai; Lee, Cheng-Kuang; Yang, Chih-Hsun; Chan, Ming-Che; Lee, Ya-Ju

    2015-11-16

    Blood coagulation is the clotting and subsequent dissolution of the clot following repair to the damaged tissue. However, inducing blood coagulation is difficult for some patients with homeostasis dysfunction or during surgery. In this study, we proposed a method to develop an integrated system that combines optical coherence tomography (OCT) and laser microsurgery for blood coagulation. Also, an algorithm for positioning of the treatment location from OCT images was developed. With OCT scanning, 2D/3D OCT images and angiography of tissue can be obtained simultaneously, enabling to noninvasively reconstruct the morphological and microvascular structures for real-time monitoring of changes in biological tissues during laser microsurgery. Instead of high-cost pulsed lasers, continuous-wave laser diodes (CW-LDs) with the central wavelengths of 450 nm and 532 nm are used for blood coagulation, corresponding to higher absorption coefficients of oxyhemoglobin and deoxyhemoglobin. Experimental results showed that the location of laser exposure can be accurately controlled with the proposed approach of imaging-based feedback positioning. Moreover, blood coagulation can be efficiently induced by CW-LDs and the coagulation process can be monitored in real-time with OCT. This technology enables to potentially provide accurate positioning for laser microsurgery and control the laser exposure to avoid extra damage by real-time OCT imaging.

  17. Optical coherence tomography-guided laser microsurgery for blood coagulation with continuous-wave laser diode

    PubMed Central

    Chang, Feng-Yu; Tsai, Meng-Tsan; Wang, Zu-Yi; Chi, Chun-Kai; Lee, Cheng-Kuang; Yang, Chih-Hsun; Chan, Ming-Che; Lee, Ya-Ju

    2015-01-01

    Blood coagulation is the clotting and subsequent dissolution of the clot following repair to the damaged tissue. However, inducing blood coagulation is difficult for some patients with homeostasis dysfunction or during surgery. In this study, we proposed a method to develop an integrated system that combines optical coherence tomography (OCT) and laser microsurgery for blood coagulation. Also, an algorithm for positioning of the treatment location from OCT images was developed. With OCT scanning, 2D/3D OCT images and angiography of tissue can be obtained simultaneously, enabling to noninvasively reconstruct the morphological and microvascular structures for real-time monitoring of changes in biological tissues during laser microsurgery. Instead of high-cost pulsed lasers, continuous-wave laser diodes (CW-LDs) with the central wavelengths of 450 nm and 532 nm are used for blood coagulation, corresponding to higher absorption coefficients of oxyhemoglobin and deoxyhemoglobin. Experimental results showed that the location of laser exposure can be accurately controlled with the proposed approach of imaging-based feedback positioning. Moreover, blood coagulation can be efficiently induced by CW-LDs and the coagulation process can be monitored in real-time with OCT. This technology enables to potentially provide accurate positioning for laser microsurgery and control the laser exposure to avoid extra damage by real-time OCT imaging. PMID:26568136

  18. Microwave detector

    DOEpatents

    Meldner, H.W.; Cusson, R.Y.; Johnson, R.M.

    1985-02-08

    A microwave detector is provided for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations. A biased ferrite produces a magnetization field flux that links a B-dot loop. The magnetic field of the microwave pulse participates in the formation of the magnetization field flux. High-frequency insensitive means are provided for measuring electric voltage or current induced in the B-dot loop. The recorded output of the detector is proportional to the time derivative of the square of the envelope shape of the microwave pulse.

  19. Microwave detector

    DOEpatents

    Meldner, Heiner W.; Cusson, Ronald Y.; Johnson, Ray M.

    1986-01-01

    A microwave detector (10) is provided for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations. A biased ferrite (26, 28) produces a magnetization field flux that links a B-dot loop (16, 20). The magnetic field of the microwave pulse participates in the formation of the magnetization field flux. High-frequency insensitive means (18, 22) are provided for measuring electric voltage or current induced in the B-dot loop. The recorded output of the detector is proportional to the time derivative of the square of the envelope shape of the microwave pulse.

  20. Theoretical Modeling for Hepatic Microwave Ablation

    PubMed Central

    Prakash, Punit

    2010-01-01

    Thermal tissue ablation is an interventional procedure increasingly being used for treatment of diverse medical conditions. Microwave ablation is emerging as an attractive modality for thermal therapy of large soft tissue targets in short periods of time, making it particularly suitable for ablation of hepatic and other tumors. Theoretical models of the ablation process are a powerful tool for predicting the temperature profile in tissue and resultant tissue damage created by ablation devices. These models play an important role in the design and optimization of devices for microwave tissue ablation. Furthermore, they are a useful tool for exploring and planning treatment delivery strategies. This review describes the status of theoretical models developed for microwave tissue ablation. It also reviews current challenges, research trends and progress towards development of accurate models for high temperature microwave tissue ablation. PMID:20309393

  1. International reference standards in coagulation.

    PubMed

    Raut, Sanj; Hubbard, Anthony R

    2010-07-01

    Measurement of coagulation factor activity using absolute physico-chemical techniques is not possible and estimation therefore relies on comparative bioassay relative to a reference standard with a known or assigned potency. However the inherent variability of locally prepared and calibrated reference standards can give rise to poor agreement between laboratories and methods. Harmonisation of measurement between laboratories at the international level relies on the availability of a common source of calibration for local reference standards and this is provided by the World Health Organization (WHO) International Standards which define the International Unit for the analyte. This article describes the principles, practices and problems of biological standardisation and the development and use of reference standards for assays of coagulation factors, with particular emphasis on WHO International Standards for both concentrates and plasma.

  2. Coagulation Changes During Graded Orhostatic Stress and Recovery

    NASA Astrophysics Data System (ADS)

    Goswami, Nandu; Cvirn, Gerhard; Schlagenhauf, Aaxel; Leschnik, Bettina; Koestenberger, Martin; Roessler, Andreas; Jantscher, Andreas; Waha, James Elvis; Wolf, Sabine; Vrecko, Karoline; Juergens, Guenther; Hinghofer-Szalkay, Helmut

    2013-02-01

    Background: Orthostatic stress has been introduced as a novel paradigm for activating the coagulation system. We examined whether graded orthostatic stress (using head up tilt, HUT + lower body negative pressure, LBNP) until presyncope leads to anti / pro-coagulatory changes and how rapidly they return to baseline during recovery. Methodology: Eight male subjects were enrolled in this study. Presyncopal runs were carried out using HUT + LBNP. At minute zero, the tilt table was brought from 0° (supine) to 70 ° head-up position for 4 min, after which pressure in the LBNP chamber was reduced to -15, -30, and -45 mm Hg every 4 min. At presyncope, the subjects were returned to supine position. Coagulatory responses and plasma mass density (for volume changes) were measured before, during and 20 min after the orthostatic stress. Whole blood coagulation was examined by means of thrombelastometry. Platelet aggregation in whole blood was examined by using impedance aggregometry. Thrombin generation parameters, prothrombin levels, and markers of endothelial activation were measured in plasma samples. Results: At presyncope, plasma volume was 20 % below the initial supine value. Blood cell counts, prothrombin levels, thrombin peak, endogenous thrombin potential (ETP), and tissue factor pathway inhibitor (TFPI) levels increased during the protocol, commensurate with hemoconcentration. The markers of endothelial activation (tissue factor, TF, tissue plasminogen activator, t-PA) and the markers of thrombin generation (Prothrombin fragments 1 and 2, F1+2, and thrombin-antithrombin complex, TAT) increased significantly. During recovery, all the coagulation parameters returned to initial supine values except F1 +2 and TAT. Conclusion: Head-up tilt/LBNP leads to activation of the coagulation system. Some of the markers of thrombin formation are still at higher than supine levels during recovery.

  3. [Monitoring of blood coagulation in perioperative care].

    PubMed

    Ishii, Hisanari

    2012-01-01

    Coagulation disorders often occur perioperatively and monitoring of blood coagulation should be fast and adequate to treat these disorders to protect patients from massive bleeding. Control of hemostasis is one of the main issues in major surgeries. Coagulation test results from a central laboratory may delay making such a perioperative decision. Recently, point-of-care monitoring (POCM), which is able to examine coagulation disorder in an operation theater with short waiting time, has become important. Both prothrombin time (PT) and activated clotting time (ACT) are very useful and popular, but also criticized because they can be monitored only until fibrin formation. On the other hand, viscoelastic monitorings of whole blood, are able to estimate fibrin formation, clot fixation, platelet function and fibrinolysis. In this review article, among variable perioperative POCMs of blood coagulation, three thromboelastographic monitorings, such as TEG ROTEM, and Sonoclot as well as PT and ACT, are described along with their utilities and limits to examine perioperative coagulation.

  4. Change of coagulation parameters after double plateletpheresis.

    PubMed

    Yilmaz, Mustafa; Dikmen, Tamer; Sonmez, Mehmet; Akdogan, Elif; Durmus, Ahmet; Omay, Serdar Bedii; Ovali, Ercument

    2007-10-01

    In the previous studies, some authors reported that automated apheresis leads to a hypercoagulable state. We tried to find out changes in coagulation parameters after double plateletpheresis in this study. Forty-five donors were recruited to the study, and coagulation parameters were assessed before and after double plateletpheresis. After double plateletpheresis, fibrinogen, factor V, factor VIII and factor IX were decreased compared with the values before apheresis. Although serum levels of this coagulation parameters are decreasing, they are still in the normal limits. Therefore, we suggest that double plateletpheresis is a safe procedure for healthy volunteers taking into account these coagulation parameters.

  5. Microwave detector

    SciTech Connect

    Meldner, H.W.; Cusson, R.Y.; Johnson, R.M.

    1986-12-02

    A detector is described for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations, the detector comprising: a B-dot loop linking the magnetic field of the microwave pulse; a biased ferrite, that produces a magnetization field flux that links the B-dot loop. The ferrite is positioned within the B-dot loop so that the magnetic field of the microwave pulse interacts with the ferrite and thereby participates in the formation of the magnetization field flux; and high-frequency insensitive means for measuring electric voltage or current induced in the B-dot loop.

  6. Interconnections between autophagy and the coagulation cascade in hepatocellular carcinoma

    PubMed Central

    Chen, K-D; Wang, C-C; Tsai, M-C; Wu, C-H; Yang, H-J; Chen, L-Y; Nakano, T; Goto, S; Huang, K-T; Hu, T-H; Chen, C-L; Lin, C-C

    2014-01-01

    Autophagy has an important role in tumor biology of hepatocellular carcinoma (HCC). Recent studies demonstrated that tissue factor (TF) combined with coagulation factor VII (FVII) has a pathological role by activating a G-protein-coupled receptor called protease-activated receptor 2 (PAR2) for tumor growth. The present study aimed to investigate the interactions of autophagy and the coagulation cascade in HCC. Seventy HCC patients who underwent curative liver resection were recruited. Immunohistochemical staining and western blotting were performed to determine TF, FVII, PAR2 and light chain 3 (LC3A/B) expressions in tumors and their contiguous normal regions. We found that the levels of autophagic marker LC3A/B-II and coagulation proteins (TF, FVII and PAR2) were inversely correlated in human HCC tissues. Treatments with TF, FVII or PAR2 agonist downregulated LC3A/B-II with an increased level of mTOR in Hep3B cells; in contrast, knockdown of TF, FVII or PAR2 increased LC3A/B. Furthermore, mTOR silencing restored the impaired expression of LC3A/B-II in TF-, FVII- or PAR2-treated Hep3B cells and activated autophagy. Last, as an in vivo correlate, we administered TF, FVII or PAR2 agonist in a NOD/severe combined immunodeficiency xenograft model and showed decreased LC3A/B protein levels in HepG2 tumors with treatments. Overall, our present study demonstrated that TF, FVII and PAR2 regulated autophagy mainly via mTOR signaling. The interaction of coagulation and autophagic pathways may provide potential targets for further therapeutic application in HCC. PMID:24853422

  7. Interconnections between autophagy and the coagulation cascade in hepatocellular carcinoma.

    PubMed

    Chen, K-D; Wang, C-C; Tsai, M-C; Wu, C-H; Yang, H-J; Chen, L-Y; Nakano, T; Goto, S; Huang, K-T; Hu, T-H; Chen, C-L; Lin, C-C

    2014-05-22

    Autophagy has an important role in tumor biology of hepatocellular carcinoma (HCC). Recent studies demonstrated that tissue factor (TF) combined with coagulation factor VII (FVII) has a pathological role by activating a G-protein-coupled receptor called protease-activated receptor 2 (PAR2) for tumor growth. The present study aimed to investigate the interactions of autophagy and the coagulation cascade in HCC. Seventy HCC patients who underwent curative liver resection were recruited. Immunohistochemical staining and western blotting were performed to determine TF, FVII, PAR2 and light chain 3 (LC3A/B) expressions in tumors and their contiguous normal regions. We found that the levels of autophagic marker LC3A/B-II and coagulation proteins (TF, FVII and PAR2) were inversely correlated in human HCC tissues. Treatments with TF, FVII or PAR2 agonist downregulated LC3A/B-II with an increased level of mTOR in Hep3B cells; in contrast, knockdown of TF, FVII or PAR2 increased LC3A/B. Furthermore, mTOR silencing restored the impaired expression of LC3A/B-II in TF-, FVII- or PAR2-treated Hep3B cells and activated autophagy. Last, as an in vivo correlate, we administered TF, FVII or PAR2 agonist in a NOD/severe combined immunodeficiency xenograft model and showed decreased LC3A/B protein levels in HepG2 tumors with treatments. Overall, our present study demonstrated that TF, FVII and PAR2 regulated autophagy mainly via mTOR signaling. The interaction of coagulation and autophagic pathways may provide potential targets for further therapeutic application in HCC.

  8. The role of coagulation/fibrinolysis during Streptococcus pyogenes infection

    PubMed Central

    Loof, Torsten G.; Deicke, Christin; Medina, Eva

    2014-01-01

    The hemostatic system comprises platelet aggregation, coagulation and fibrinolysis and is a host defense mechanism that protects the integrity of the vascular system after tissue injury. During bacterial infections, the coagulation system cooperates with the inflammatory system to eliminate the invading pathogens. However, pathogenic bacteria have frequently evolved mechanisms to exploit the hemostatic system components for their own benefit. Streptococcus pyogenes, also known as Group A Streptococcus, provides a remarkable example of the extraordinary capacity of pathogens to exploit the host hemostatic system to support microbial survival and dissemination. The coagulation cascade comprises the contact system (also known as the intrinsic pathway) and the tissue factor pathway (also known as the extrinsic pathway), both leading to fibrin formation. During the early phase of S. pyogenes infection, the activation of the contact system eventually leads to bacterial entrapment within a fibrin clot, where S. pyogenes is immobilized and killed. However, entrapped S. pyogenes can circumvent the antimicrobial effect of the clot by sequestering host plasminogen on the bacterial cell surface that, after conversion into its active proteolytic form, plasmin, degrades the fibrin network and facilitates the liberation of S. pyogenes from the clot. Furthermore, the surface-localized fibrinolytic activity also cleaves a variety of extracellular matrix proteins, thereby enabling S. pyogenes to migrate across barriers and disseminate within the host. This review summarizes the knowledge gained during the last two decades on the role of coagulation/fibrinolysis in host defense against S. pyogenes as well as the strategies developed by this pathogen to evade and exploit these host mechanisms for its own benefit. PMID:25309880

  9. Blood coagulation activation and fibrinolysis during a downhill marathon run.

    PubMed

    Sumann, Günther; Fries, Dietmar; Griesmacher, Andrea; Falkensammer, Gerda; Klingler, Anton; Koller, Arnold; Streif, Werner; Greie, Sven; Schobersberger, Beatrix; Schobersberger, Wolfgang

    2007-07-01

    Prolonged physical exercise is associated with multiple changes in blood hemostasis. Eccentric muscle activation induces microtrauma of skeletal muscles, inducing an inflammatory response. Since there is a link between inflammation and coagulation we speculated that downhill running strongly activates the coagulation system. Thirteen volunteers participated in the Tyrolean Speed Marathon (42,195 m downhill race, 795 m vertical distance). Venous blood was collected 3 days (T1) and 3 h (T2) before the run, within 30 min after finishing (T3) and 1 day thereafter (T4). We measured the following key parameters: creatine kinase, myoglobin, thrombin-antithrombin complex, prothrombin fragment F1 + 2, D-dimer, plasmin-alpha(2)-antiplasmin complexes, tissue-type plasminogen activator antigen, plasminogen-activator-inhibitor-1 antigen and thrombelastography with ROTEM [intrinsic pathway (InTEM) clotting time, clot formation time, maximum clot firmness, alpha angle]. Thrombin generation was evaluated by the Thrombin Dynamic Test and the Technothrombin TGA test. Creatine kinase and myoglobin were elevated at T3 and further increased at T4. Thrombin-antithrombin complex, prothrombin fragment F1 + 2, D-dimer, plasmin-alpha(2)-antiplasmin complexes, tissue-type plasminogen activator antigen and plasminogen-activator-inhibitor-1 antigen were significantly increased at T3. ROTEM analysis exhibited a shortening of InTEM clotting time and clot formation time after the marathon, and an increase in InTEM maximum clot firmness and alpha angle. Changes in TGA were indicative for thrombin generation after the marathon. We demonstrated that a downhill marathon induces an activation of coagulation, as measured by specific parameters for coagulation, ROTEM and thrombin generation assays. These changes were paralleled by an activation of fibrinolysis indicating a preserved hemostatic balance.

  10. Transcatheter Microwave Antenna

    NASA Technical Reports Server (NTRS)

    Arndt, Dickey G. (Inventor); Carl, James R. (Inventor); Ngo, Phong (Inventor); Raffoul, George W. (Inventor)

    2001-01-01

    A method, simulation, and apparatus are provided that are highly suitable for treatment of benign prostatic hyperplasia (BPH). A catheter is disclosed that includes a small diameter disk loaded monopole antenna surrounded by fusion material having a high heat of fusion and a melting point preferably at or near body temperature. Microwaves from the antenna heat prostatic tissue to promote necrosing of the prostatic tissue that relieves the pressure of the prostatic tissue against the urethra as the body reabsorbs the necrosed or dead tissue. The fusion material keeps the urethra cool by means of the heat of fusion of the fusion material. This prevents damage to the urethra while the prostatic tissue is necrosed. A computer simulation is provided that can be used to predict the resulting temperature profile produced in the prostatic tissue. By changing the various control features of the catheter and method of applying microwave energy a temperature profile can be predicted and produced that is similar to the temperature profile desired for the particular patient.

  11. Microwave generator

    DOEpatents

    Kwan, T.J.T.; Snell, C.M.

    1987-03-31

    A microwave generator is provided for generating microwaves substantially from virtual cathode oscillation. Electrons are emitted from a cathode and accelerated to an anode which is spaced apart from the cathode. The anode has an annular slit there through effective to form the virtual cathode. The anode is at least one range thickness relative to electrons reflecting from the virtual cathode. A magnet is provided to produce an optimum magnetic field having the field strength effective to form an annular beam from the emitted electrons in substantial alignment with the annular anode slit. The magnetic field, however, does permit the reflected electrons to axially diverge from the annular beam. The reflected electrons are absorbed by the anode in returning to the real cathode, such that substantially no reflexing electrons occur. The resulting microwaves are produced with a single dominant mode and are substantially monochromatic relative to conventional virtual cathode microwave generators. 6 figs.

  12. Coagulative and ablative characteristics of a novel diode laser system (1470nm) for endonasal applications

    NASA Astrophysics Data System (ADS)

    Betz, C. S.; Havel, M.; Janda, P.; Leunig, A.; Sroka, R.

    2008-02-01

    Introduction: Being practical, efficient and inexpensive, fibre guided diode laser systems are preferable over others for endonasal applications. A new medical 1470 nm diode laser system is expected to offer good ablative and coagulative tissue effects. Methods: The new 1470 nm diode laser system was compared to a conventional 940 nm system with regards to laser tissue effects (ablation, coagulation, carbonization zones) in an ex vivo setup using fresh liver and muscle tissue. The laser fibres were fixed to a computer controlled stepper motor, and the light was applied using comparable power settings and a reproducible procedure under constant conditions. Clinical efficacy and postoperative morbidity was evaluated in two groups of 10 patients undergoing laser coagulation therapy of hyperplastic nasal turbinates. Results: In the experimental setup, the 1470 nm laser diode system proved to be more efficient in inducing tissue effects with an energy factor of 2-3 for highly perfused hepatic tissue to 30 for muscular tissue. In the clinical case series, the higher efficacy of the 1470 nm diode laser system led to reduced energy settings as compared to the conventional system with comparable clinical results. Postoperative crusting was less pronounced in the 1470 nm laser group. Conclusion: The 1470 nm diode laser system offers a highly efficient alternative to conventional diode laser systems for the coagulation of hyperplastic nasal turbinates. According to the experimental results it can be furthermore expected that it disposes of an excellent surgical potential with regards to its cutting abilities.

  13. Virus inactivation in aluminum and polyaluminum coagulation.

    PubMed

    Matsui, Yoshihiko; Matsushita, Taku; Sakuma, Satoru; Gojo, Takahito; Mamiya, Teppei; Suzuoki, Hiroshi; Inoue, Takanobu

    2003-11-15

    Inorganic aluminum salts, such as aluminum sulfate, are coagulants that cause small particles, such as bacteria and viruses as well as inorganic particles, to destabilize and combine into larger aggregates. In this investigation, batch coagulation treatments of water samples spiked with Qbeta, MS2, T4, and P1 viruses were conducted with four different aluminum coagulants. The total infectious virus concentration in the suspension of floc particles that eventually formed by dosing with coagulant was measured after the floc particles were dissolved by raising the pH with an alkaline beef extract solution. The virus concentrations were extremely reduced after the water samples were dosed with aluminum coagulants. Viruses mixed with and adsorbed onto preformed aluminum hydroxide floc were, however, completely recovered after the floc dissolution. These results indicated that the aluminum coagulation process inactivates viruses. Virucidal activity was most prominent with the prehydrolyzed aluminum salt coagulant, polyaluminum chloride (PACl). Virucidal activity was lower in river water than in ultrapure water--natural organic matter in the river water depressed the virucidal activity. Mechanisms and kinetics of the virus inactivation were discussed. Our results suggest that intermediate polymers formed during hydrolysis of the aluminum coagulants sorbed strongly to viruses, either rendering them inactive or preventing infectivity.

  14. [Blood coagulation disorders in oncological patients].

    PubMed

    von Depka Prondzinski, M

    2005-01-01

    Patients with malignancies often experience acute disorders of coagulation. They may manifest as thromboembolism, disseminated intravascular coagulation or a tendency to bleed. Either disorder carries a high rate of complications and a difficult task in diagnosing and treating them. Some complications typical for patients with malignancies are discussed. Among these are tumor associated thrombophilia, acquired von Willebrand's disease, and thrombocytopenia.

  15. Pretreatment in a high-pressure microwave processor for MIB-1 immunostaining of cytological smears and paraffin tissue sections to visualize the various phases of the mitotic cycle.

    PubMed

    Suurmeijer, A J; Boon, M E

    1999-08-01

    In many pathology laboratories, both microwave ovens and pressure cookers are used for pretreatment of cytologic smears and paraffin sections to allow MIB-1 staining. For both methods there are two problems. First, the results cannot be used for quantitation because standardization is impossible. Second, the staining results are often suboptimal, resulting in negative staining of cells in the G(1)- and S-phases. When pretreatment is performed in a microwave processor, allowing microwave heating under pressure, precise temperature monitoring becomes possible. In addition, the importance of the pH of the buffer was studied using a test battery series. Optimal staining is achieved at a temperature of 115C, 10 min, pH 6. This method proved to be highly reproducible. Because the immunostaining results are optimal, the various phases of the cell cycle can be defined in the sections and smears. In addition, the perinucleolar staining of the late G(1)-phase is optimally visualized and nuclei of the stable pKi-67 pathway can be identified. Under suboptimal conditions, in particular, the number of cells in the late G(1)-phase are underestimated in the MIB-1 counts.

  16. Textile wastewater purification through natural coagulants

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

    A new coagulant obtained through polymerization of Acacia mearnsii de Wild tannin extract has been characterized in the removal of two dangerous dye pollutants: Alizarin Violet 3R and Palatine Fast Black WAN. This coagulant is lab-synthesized according to the etherification of tannins with glycidyltrimethylammonium chloride and formaldehyde and its performance in dye removal in terms of efficiency was high. Reasonably low coagulant dosages (ca. 50 mg L-1) reaches high capacity levels (around 0.8 for Alizarin Violet 3R and 1.6 for Palatine Fast Black WAN mg dye mg-1 of coagulant) and pH and temperature are not extremely affecting variables. The systems coagulant dyes were successfully modeled by applying the Langmuir hypothesis. q max and b parameters were obtained with an adjusted correlation factor ( r 2) above 0.8.

  17. Immunoassays for diagnosis of coagulation disorders.

    PubMed

    Kappel, A; Ehm, M

    2010-11-01

    Immunoassays play a pivotal role in the clinical laboratory. In the coagulation section of the laboratory, they are used as an aid for diagnosis of deep vein thrombosis or pulmonary embolism, thrombophilia screening, or detection of coagulation factor deficiencies, respectively. Enzyme-linked immunosorbent assay (ELISA) and latex agglutination immunoassay technologies are currently most widely used, while Luminescent Oxygen Channeling Immunoassay (LOCI®) and other chemiluminescence-based immunoassays are emerging technologies for the coagulation laboratory. However, not all immunoassay technologies employed are compatible with the workflow requirements of the coagulation laboratory, and, not all technologies are suitable for detection or quantification of every marker. This review focuses on technical and performance aspects of those immunoassay technologies that are most widely used in the coagulation laboratory, and provides a description of markers that are typically tested by immunoassays.

  18. Medical applications of microwave imaging.

    PubMed

    Wang, Zhao; Lim, Eng Gee; Tang, Yujun; Leach, Mark

    2014-01-01

    Ultrawide band (UWB) microwave imaging is a promising method for the detection of early stage breast cancer, based on the large contrast in electrical parameters between malignant tumour tissue and the surrounding normal breast-tissue. In this paper, the detection and imaging of a malignant tumour are performed through a tomographic based microwave system and signal processing. Simulations of the proposed system are performed and postimage processing is presented. Signal processing involves the extraction of tumour information from background information and then image reconstruction through the confocal method delay-and-sum algorithms. Ultimately, the revision of time-delay and the superposition of more tumour signals are applied to improve accuracy.

  19. Utilizing commercial microwave for rapid and effective immunostaining.

    PubMed

    Owens, Katrina; Park, Ji H; Kristian, Tibor

    2013-09-30

    There is an accumulating literature demonstrating the application of microwaves across a wide spectrum of histological techniques. Although exposure to microwaves for short periods resulted in substantial acceleration of all procedures this technique still is not adopted widely. In part, this may be due to concerns over solutions that will avoid induction of thermal damage to the tissue when using standard microwave. Here, we offer a cooling setup that can be used with conventional microwave ovens. We utilized dry ice for effective cooling during microwave irradiation of tissue samples. To prevent overheating, the cups with tissue during exposure to microwaves were surrounded with powdered dry ice. Since the dry ice does not touch the walls of the cups, freezing is prevented. Overheating is avoided by alternating the microwave treatment with 1-2 min time periods when the cups are cooled outside of the microwave oven. This technique was used on mouse brain sections that were immunostained with microglia-specific CD68 antiserum and astrocyte labeling GFAP antibody. Both standard and microwave-assisted immonolabeling gave comparable results visualizing cells with fine processes and low background signal. Short incubation time in the microwave requires high concentrations of antibody for tissue immunostaining. We show that by prolonging the microwaving procedure we were able to reduce the antibody concentration to the levels used in standard immunostaining protocol. In summary, our technique gives a possibility to use a conventional microwave for rapid and effective immunolabeling resulting in reduced amount of antibody required for satisfactory immunostaining.

  20. Platelets and neutrophil extracellular traps collaborate to promote intravascular coagulation during sepsis in mice.

    PubMed

    McDonald, Braedon; Davis, Rachelle P; Kim, Seok-Joo; Tse, Mandy; Esmon, Charles T; Kolaczkowska, Elzbieta; Jenne, Craig N

    2017-03-09

    Neutrophil extracellular traps (NETs; webs of DNA coated in antimicrobial proteins) are released into the vasculature during sepsis where they contribute to host defense, but also cause tissue damage and organ dysfunction. Various components of NETs have also been implicated as activators of coagulation. Using multicolor confocal intravital microscopy in mouse models of sepsis, we observed profound platelet aggregation, thrombin activation, and fibrin clot formation within (and downstream of) NETs in vivo. NETs were critical for the development of sepsis-induced intravascular coagulation regardless of the inciting bacterial stimulus (gram-negative, gram-positive, or bacterial products). Removal of NETs via DNase infusion, or in peptidylarginine deiminase-4-deficient mice (which have impaired NET production), resulted in significantly lower quantities of intravascular thrombin activity, reduced platelet aggregation, and improved microvascular perfusion. NET-induced intravascular coagulation was dependent on a collaborative interaction between histone H4 in NETs, platelets, and the release of inorganic polyphosphate. Real-time perfusion imaging revealed markedly improved microvascular perfusion in response to the blockade of NET-induced coagulation, which correlated with reduced markers of systemic intravascular coagulation and end-organ damage in septic mice. Together, these data demonstrate, for the first time in an in vivo model of infection, a dynamic NET-platelet-thrombin axis that promotes intravascular coagulation and microvascular dysfunction in sepsis.

  1. Interstitial laser coagulation therapy for benign prostatic hyperplasia

    NASA Astrophysics Data System (ADS)

    McNicholas, Thomas A.; Alsudani, Mohammed

    1996-05-01

    Alternatives to the side-firing laser method include controlled destruction of prostatic adenoma by an atraumatic saline cooled laser fiber introduced endoscopically into the prostate under visual and transrectal ultrasound (TRUS) control. Laser light produces intense heating and interstitial laser coagulation (ILC) occurs with characteristic TRUS changes which are used to control the volume of tissue destruction. The prostatic urethral lining is preserved which may reduce laser side effects). Thirty-six men with symptomatic BPH were treated by ILC between April 1994 and September 1995. All were discharged home on the first post-operative day and reviewed periodically to 12 months post-treatment with measurement of IPSS, flow rate (FR), residual volume, complications, potency and TRUS. Seventeen men (47%) voided immediately, 15 (42%) performed intermittent self-catheterization (ISC) for 3.5 days (2 - 5). Four men (11%) required catheterization for 1/52. Thirty-five men tolerated the treatment well, requiring only mild oral analgesia. One man developed dysuria and required early transurethral resection revealing a large volume of coagulative necrosis. Improvement in symptoms and flow rate developed from 1 - 30 days later. There were no significant complications. Hyperechoic and cystic zones developed at the ILC site which persisted to 12 months. This clinical study indicates the feasibility and safety of intense heating by ILC with visible and ultrasound control to coagulate the adenoma while preserving the urethra. Changes are easily seen on TRUS, symptomatic improvement is good and there have been minimal urethral symptoms or complications.

  2. Crosstalk between inflammation and coagulation: the lessons of sepsis.

    PubMed

    van der Poll, Tom; Levi, Marcel

    2012-09-01

    Sepsis results in the concurrent activation of inflammatory and procoagulant pathways. Bacterial products and proinflammatory cytokines trigger the coagulation system primarily via induction of tissue factor. During sepsis, activation of coagulation is accompanied by impaired function of major anticoagulant mechanisms, including antithrombin, the protein C system and fibrinolysis. Protease activated receptors (PARs) form the molecular connection between coagulation and inflammation, and especially PAR1 seems to play an eminent role in sepsis pathogenesis. Activated protein C (APC) can cleave PAR1 when associated with either the endothelial protein C receptor (EPCR) or CD11b/CD18, resulting in broad cytoprotective effects mediated by sphingosine 1 phosphate (S1P) receptor 1 (S1P1). In contrast, activation of PAR1 by high dose thrombin results in barrier disruptive effects in endothelial cells via an S1P3 dependent mechanism. Recombinant APC protects against mortality in experimental endotoxemia and sepsis by effects that can be mediated by either EPCR - PAR1 dependent (endothelial cells, dendritic cells) or CD11b/CD18 - PAR1 dependent (macrophages) mechanisms. These protective APC effects do not rely on the anticoagulant properties of this protein. APC mutants that lack anticoagulant properties but retain the capacity to activate PAR1 are promising new drugs for sepsis treatment.

  3. Microwave furnace having microwave compatible dilatometer

    DOEpatents

    Kimrey, H.D. Jr.; Janney, M.A.; Ferber, M.K.

    1992-03-24

    An apparatus for measuring and monitoring a change in the dimension of a sample being heated by microwave energy is described. The apparatus comprises a microwave heating device for heating a sample by microwave energy, a microwave compatible dilatometer for measuring and monitoring a change in the dimension of the sample being heated by microwave energy without leaking microwaves out of the microwave heating device, and a temperature determination device for measuring and monitoring the temperature of the sample being heated by microwave energy. 2 figs.

  4. Microwave furnace having microwave compatible dilatometer

    DOEpatents

    Kimrey, Jr., Harold D.; Janney, Mark A.; Ferber, Mattison K.

    1992-01-01

    An apparatus for measuring and monitoring a change in the dimension of a sample being heated by microwave energy is described. The apparatus comprises a microwave heating device for heating a sample by microwave energy, a microwave compatible dilatometer for measuring and monitoring a change in the dimension of the sample being heated by microwave energy without leaking microwaves out of the microwave heating device, and a temperature determination device for measuring and monitoring the temperature of the sample being heated by microwave energy.

  5. Blood coagulation reactions on nanoscale membrane surfaces

    NASA Astrophysics Data System (ADS)

    Pureza, Vincent S.

    Blood coagulation requires the assembly of several membrane-bound protein complexes composed of regulatory and catalytic subunits. The biomembranes involved in these reactions not only provide a platform for these procoagulant proteins, but can also affect their function. Increased exposure of acidic phospholipids on the outer leaflet of the plasma membrane can dramatically modulate the catalytic efficiencies of such membrane-bound enzymes. Under physiologic conditions, however, these phospholipids spontaneously cluster into a patchwork of membrane microdomains upon which membrane binding proteins may preferentially assemble. As a result, the membrane composition surrounding these proteins is largely unknown. Through the development and use of a nanometer-scale bilayer system that provides rigorous control of the phospholipid membrane environment, I investigated the role of phosphatidylserine, an acidic phospholipid, in the direct vicinity (within nanometers) of two critical membrane-bound procoagulant protein complexes and their respective natural substrates. Here, I present how the assembly and function of the tissue factor˙factor VIIa and factor Va˙factor Xa complexes, the first and final cofactor˙enzyme complexes of the blood clotting cascade, respectively, are mediated by changes in their immediate phospholipid environments.

  6. Inflammation and coagulation in urticaria and angioedema.

    PubMed

    Cugno, Massimo; Asero, Riccardo; Tedeschi, Alberto; Lazzari, Riccardo; Marzano, Angelo V

    2012-09-01

    Urticaria is a skin disease characterised by short-lived surface swellings of the dermis (wheals) frequently accompanied by itching. It is classified as acute or chronic depending on whether the wheal recurrence occurs for less or more than six weeks. Acute urticaria is often due to a hypersensitivity reaction, whereas about 50% of the cases of chronic urticaria are regarded as autoimmune. Urticaria may occur alone or in association with a deeper swelling (angioedema) involving the subcutaneous and/or submucosal tissues, and last from hours to a few days. Angioedema can also develop alone, and may be idiopathic or be caused by allergies, inherited or acquired deficiencies of C1-inhibitor protein, or adverse drug reactions. An interplay between inflammation and coagulation has been proposed as a pathomechanism in urticaria and urticaria-associated angioedema (in which histamine and thrombin are involved), as well as in angioedema due to C1-inhibitor deficiency, which involves various biological systems. An increase in the plasma markers of thrombin generation, fibrinolysis and inflammation has been documented during exacerbations of urticaria and angioedema, with the marker levels decreasing to normal during remission. However, the hypercoagulable state in chronic urticaria and angioedema has not been reported to be associated with any increased risk of thrombosis, although there have been a number of reports of cardiovascular events occurring during episodes of acute urticaria. These observations have provided the rationale for the clinical evaluation of anticoagulant and antifibrinolytic drugs, the efficacy of which has sometimes been demonstrated.

  7. Coagulation assessment by rotation thrombelastometry in normal pregnancy.

    PubMed

    Huissoud, Cyril; Carrabin, Nicolas; Benchaib, Mehdi; Fontaine, Oriane; Levrat, Albrice; Massignon, Denis; Touzet, Sandrine; Rudigoz, René-Charles; Berland, Michel

    2009-04-01

    We analysed changes in coagulation during normal pregnancy with a novel point-of-care device based on thrombelastometry (ROTEM). We compared the results obtained with those of standard coagulation tests in 104 patients: 20 non-pregnant women (controls) and 84 women in the first (T1, n = 17), second (T2, n = 9) and third (T3, n = 58) trimesters of pregnancy. We measured the clotting time (CT), the maximum clot firmness (MCF), the early clot amplitude at 5 and 15 minutes (CA(5), CA(15)) and the clot lysis index (CLI(30)) with four tests containing specific reagents. (a) The INTEM test involving ellagic acid activated the intrinsic pathway and (b) the EXTEM test using tissue factor triggered the extrinsic pathway; (c) The FIBTEM test based on a platelet inhibitor (cytochalasin D) evaluated the contribution of fibrinogen to clot formation and (d) the APTEM test was similar to the EXTEM but was based on inhibition in vitro of fibrinolysis by aprotinin. CT and CLI(30) were not significantly modified during pregnancy whereas MCF, CA(5) and CA(15) (INTEM, EXTEM, FIBTEM) increased significantly between the second and third trimesters (e.g. median [interquartile range]: MCF-FIBTEM, 13 [11-16] mm vs. 19 [17-23] mm, respectively, in controls and T3, p < 0.001). EXTEM values were not significantly different from those measured with APTEM. There were significant correlations between the results obtained with ROTEM and those from standard coagulation tests. ROTEM analysis showed a marked increase in coagulability during normal pregnancy. ROTEM values may serve as the basis for future studies in pregnant women.

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

    PubMed

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

    2015-01-01

    Polymerized inorganic coagulants are increasingly being used in the water supply and wastewater treatment process, yet there is limited research on the development of polytitanium coagulants. The aim of this study is to synthesize polytitanium chloride (PTC) coagulants and investigate their coagulation behavior and floc characteristics for humic acid removal in comparison to polyaluminum chloride (PAC). The PTC samples with different B (molar ratios of OH/Ti) values were prepared using an instantaneous base-feeding method, employing sodium carbonate as the basification agent. The coagulation efficiency was significantly influenced by different B values. The results suggest that the humic acid removal increased with the increasing B value for PAC, while the inverse trend was observed for PTC. The optimum B value was chosen at 1.0 and 2.0 for PTC and PAC, respectively. Under the optimum coagulant dose and initial solution pH conditions, the PTC coagulant performed better than the PAC coagulant and the floc properties were significantly improved in terms of floc growth rate and floc size. However, the PAC coagulants produced flocs with better floc recoverability than the PTC coagulants.

  9. Stability, sterility, coagulation, and immunologic studies of salmon coagulation proteins with potential use for mammalian wound healing and cell engineering.

    PubMed

    Laidmäe, Ivo; McCormick, Margaret E; Herod, Julia L; Pastore, Jennifer J; Salum, Tiit; Sawyer, Evelyn S; Janmey, Paul A; Uibo, Raivo

    2006-12-01

    Fibrin sealants made by polymerization of fibrinogen activated by the protease thrombin have many applications in hemostasis and wound healing. In treatments of acute injury or surgical wounds, concentrated fibrin preparations mimic the initial matrix that normally prevents bleeding and acts as a scaffold for cells that initiate tissue repair. However risks of infectious disease, immunogenic reaction, and the high cost of purified human or other mammalian blood proteins limit widespread use of these materials. Purified coagulation proteins from Atlantic salmon represent a potentially safer, equally effective, and less costly alternative in part because of the low ambient temperature of these farmed animals and the absence of endogenous agents known to be infectious in mammalian hosts. This study reports rheologic measurements of lyophilized salmon fibrinogen and thrombin that demonstrate stability to prolonged storage and gamma irradiation sufficient to reduce viral loads by over five orders of magnitude. Coagulation and immunologic studies in rats and rabbits treated intraperitoneally with salmon fibrin show no deleterious effects on coagulation profiles and no cross reactivity with host fibrinogen or thrombin. The results support the potential of salmon fibrin as an alternative to mammalian proteins in clinical applications.

  10. Mineral balance in milk heated using microwave energy.

    PubMed

    de la Fuente, Miguel Angel; Olano, Agustín; Juárez, Manuela

    2002-04-10

    Milk heated to 75 and 85 degrees C in a water bath or in a microwave oven was assayed for changes in salt partitioning after cooling to room temperature. To properly to assess differences and draw valid comparisons, the two heating methods used in the experiment were applied to samples for identical exposure times, and the samples were heated to attain the same final temperatures. Although the soluble Ca and P(i) contents were lower in the heated milk samples, no significant differences in salt partitioning were found between microwave and conventional heating. Ionic calcium levels in the milk samples pasteurized using microwave energy were very close to the levels in the samples heated in a conventional water bath (approximately 90% of the level in the untreated milk samples). The microwave heating-induced changes were completely reversed after storage at 20 degrees C for 24 h. The coagulation properties of the heated milk samples were also examined, and the coagulation time was longer and the curd formation rate slower in the microwave-heated milk than in the raw milk. Still, the experimental results demonstrated that microwave heating was no more detrimental to the milk than conventional heating and could thus be used for pasteurization purposes.

  11. Hi-tech of the prostate: interstitial laser coagulation of benign prostatic hypertrophy

    NASA Astrophysics Data System (ADS)

    Muschter, Rolf; Hofstetter, Alfons G.; Hessel, Stefan F. F.; Keiditsch, Ernst; Rothenberger, Karl-Heinz; Schneede, Peter; Frank, Klaus H.

    1992-06-01

    We report on the new technique of interstitial laser coagulation of the prostate (ILCP) in the treatment of benign prostatic hyperplasia (BPH). Basic experiments by use of a Nd:YAG laser in combination with a newly designed fiber tip homogeneously distributing the laser irradiation have been performed in potato, muscle, liver, and surgically removed human BPH-tissue to determine the volume of coagulation. The coagulation zone surrounding the probe was well defined and homogeneous. The size was dependent on laser power and irradiation time. Carbonization was never present except in darker tissues irradiated with high energy. Volume and time resolved measurements correlated well with the size of coagulation. 10 W and 5 minutes, for example, resulted in a coagulation zone of 17 X 15 mm. Comparable results have been seen in in-vivo experiments in surgically exposed canine prostates. Specimen for macroscopic and microscopic examination were taken immediately after treatment and after 5 and 35 days. The well demarked coagulation necrosis of the early stage resulted in cystic degeneration and fibrosis in the later stages. This was combined with shrinkage and reduction in volume. The urothelium of the urethra, the external sphincter and the rectum showed no damage. Until now, 15 patients suffering from obstructive symptoms due to BPH have been treated with interstitial laser coagulation. The probes were inserted from the perineum into the center of each lateral lobe of the prostate by transrectal ultrasound guidance, while the median lobe was treated by urethroscopic guidance, while the median lobe was treated by urethroscopic control. Dependent on the size of the prostate irradiation, time was 5 to 10 minutes per lobe at a power setting of 5 to 10 W.

  12. Coagulation abnormalities in the cirrhotic patient.

    PubMed

    Muciño-Bermejo, Jimena; Carrillo-Esper, Raúl; Uribe, Misael; Méndez-Sánchez, Nahum

    2013-01-01

    The clotting process is a dynamic array of multiple processes which can be described in four phases: platelet plug initiation and formation, clotting process propagation by the coagulation cascade, clotting termination by antithrombotic mechanisms and clot removal by fibrinolysis. The liver plays a central role in each of these phases of clotting process, as it synthesizes the majority of coagulation factors and proteins involved in fibrinolysis as well as thrombopoeitin, which is responsible for platelet production from megakaryocytes. Many pathological processes associated with cirrhosis, such as portal hypertension and endothelial dysfunction, as well as co-morbid conditions, may also alter the coagulation process. Consequently, patients with liver disease have a disturbed balance of procoagulant and anti-coagulant factors which deviates from the normal coagulation cascade. This situation poses an additional problem in the diagnostic and therapeutic approach to this group of patients, since traditional coagulation test may not be reliable for assessing bleeding or thrombotic risk and traditional transfusional strategies may not be applicable in cirrhotic patients. In this article, we review the pathophysiological bases of coagulation abnormalities, in cirrhotic patients, the diagnostic therapeutic strategies to be followed and its impact on the clinical outcome in the cirrhotic patient.

  13. Transfusion and coagulation management in liver transplantation.

    PubMed

    Clevenger, Ben; Mallett, Susan V

    2014-05-28

    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.

  14. Transfusion and coagulation management in liver transplantation

    PubMed Central

    Clevenger, Ben; Mallett, Susan V

    2014-01-01

    There is wide variation in the management of coagulation and blood transfusion practice in liver transplantation. The use of blood products intraoperatively is declining and transfusion free transplantations take place ever more frequently. Allogenic blood products have been shown to increase morbidity and mortality. Primary haemostasis, coagulation and fibrinolysis are altered by liver disease. This, combined with intraoperative disturbances of coagulation, increases the risk of bleeding. Meanwhile, the rebalancing of coagulation homeostasis can put patients at risk of hypercoagulability and thrombosis. The application of the principles of patient blood management to transplantation can reduce the risk of transfusion. This includes: preoperative recognition and treatment of anaemia, reduction of perioperative blood loss and the use of restrictive haemoglobin based transfusion triggers. The use of point of care coagulation monitoring using whole blood viscoelastic testing provides a picture of the complete coagulation process by which to guide and direct coagulation management. Pharmacological methods to reduce blood loss include the use of anti-fibrinolytic drugs to reduce fibrinolysis, and rarely, the use of recombinant factor VIIa. Factor concentrates are increasingly used; fibrinogen concentrates to improve clot strength and stability, and prothrombin complex concentrates to improve thrombin generation. Non-pharmacological methods to reduce blood loss include surgical utilisation of the piggyback technique and maintenance of a low central venous pressure. The use of intraoperative cell salvage and normovolaemic haemodilution reduces allogenic blood transfusion. Further research into methods of decreasing blood loss and alternatives to blood transfusion remains necessary to continue to improve outcomes after transplantation. PMID:24876736

  15. Active microwaves

    NASA Technical Reports Server (NTRS)

    Evans, D.; Vidal-Madjar, D.

    1994-01-01

    Research on the use of active microwaves in remote sensing, presented during plenary and poster sessions, is summarized. The main highlights are: calibration techniques are well understood; innovative modeling approaches have been developed which increase active microwave applications (segmentation prior to model inversion, use of ERS-1 scatterometer, simulations); polarization angle and frequency diversity improves characterization of ice sheets, vegetation, and determination of soil moisture (X band sensor study); SAR (Synthetic Aperture Radar) interferometry potential is emerging; use of multiple sensors/extended spectral signatures is important (increase emphasis).

  16. Reaction-diffusion waves of blood coagulation.

    PubMed

    Galochkina, Tatiana; Bouchnita, Anass; Kurbatova, Polina; Volpert, Vitaly

    2017-03-24

    One of the main characteristics of blood coagulation is the speed of clot growth. In the current work we consider a mathematical model of the coagulation cascade and study existence, stability and speed of propagation of the reaction-diffusion waves of blood coagulation. We also develop a simplified one-equation model that reflects the main features of the thrombin wave propagation. For this equation we estimate the wave speed analytically. The resulting formulas provide a good approximation for the speed of wave propagation in a more complex model as well as for the experimental data.

  17. Acute Disseminated Intravascular Coagulation in Neuroendocrine Carcinoma

    PubMed Central

    Teh, Ru-Wen; Tsoi, Daphne T.

    2012-01-01

    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

  18. Microwave dissolution of plant tissue and the subsequent determination of trace lanthanide and actinide elements by inductively coupled plasma-mass spectrometry

    SciTech Connect

    Alvarado, J.S.; Neal, T.J.; Smith, L.L.; Erickson, M.D.

    1997-08-01

    Recently there has been much concern with the ability of plants to uptake heavy metals from their surroundings. With the development of instrumental techniques with low detection limits such as inductively coupled plasma-mass spectrometry (ICP-MS), attention is shifting toward achieving faster and more elegant ways of oxidizing the organic material inherent in environmental samples. Closed-vessel microwave dissolution was compared with conventional methods for the determination of concentrations of cerium, samarium, europium, terbium, uranium and thorium in a series of samples from the National Institute of Standards and Technology and from fields in Idaho. The ICP-MS technique exhibited detection limits in parts-per-trillion and linear calibration plots over three orders of magnitude for the elements under study. The results obtained by using nitric acid and hydrogen peroxide in a microwave digestion system for the analysis of reference materials showed close agreement with the accepted values. These values were compared with results obtained from dry- and wet-ashing procedures. The findings from an experiment comparing radiometric techniques for the determination of actinide elements to ICP-MS are reported.

  19. Microwave Treatment for Cardiac Arrhythmias

    NASA Technical Reports Server (NTRS)

    Hernandez-Moya, Sonia

    2009-01-01

    NASA seeks to transfer the NASA developed microwave ablation technology, designed for the treatment of ventricular tachycardia (irregular heart beat), to industry. After a heart attack, many cells surrounding the resulting scar continue to live but are abnormal electrically; they may conduct impulses unusually slowly or fire when they would typically be silent. These diseased areas might disturb smooth signaling by forming a reentrant circuit in the muscle. The objective of microwave ablation is to heat and kill these diseased cells to restore appropriate electrical activity in the heart. This technology is a method and apparatus that provides for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In comparison with other methods that involve direct-current pulses or radio frequencies below 1 GHz, this method may prove more effective in treating ventricular tachycardia. This is because the present method provides for greater control of the location, cross-sectional area, and depth of a lesion via selection of the location and design of the antenna and the choice of microwave power and frequency.

  20. Ferric coagulant recovered from coagulation sludge and its recycle in chemically enhanced primary treatment.

    PubMed

    Xu, G R; Yan, Z C; Wang, N; Li, G B

    2009-01-01

    An investigation was conducted to study the feasibility of ferric coagulant recovery from chemical sludge and its recycle in chemically enhanced primary treatment (CEPT) to make the process more cost-effective, as well as reduce sludge volume. The optimum conditions and efficiency of the acidification for ferric coagulant recovery from coagulation sludge were investigated. Experimental results showed that the recovered coagulants can be used in CEPT and the pollutants removal efficiency is similar to that of fresh coagulant, and for some aspects the effect of recovered coagulants is better than that of fresh ones, such as turbidity removal. Although some substances will be enriched during recycle, they have little effect on treated wastewater quality. Acidification condition also had significant influence on reduction of sludge volume. The efficiency of coagulant recovery had a linear relationship with sludge reduction. Experiments verify that it would be a sustainable and cost-effective way to recover ferric coagulant from coagulation sludge in water treatment and chemical wastewater treatment, and then recycle it to CEPT, as well as reduce sludge volume.

  1. Effects of Al-coagulant sludge characteristics on the efficiency of coagulants recovery by acidification.

    PubMed

    Chen, Yi-Jui; Wang, Wen-May; Wei, Ming-Jun; Chen, Jiann-Long; He, Ju-Liang; Chiang, Kung-Yuh; Wu, Chih-Chao

    2012-12-01

    This study evaluated the effects of Al-coagulant sludge characteristics on the efficiency ofcoagulant recovery by acidification with H2SO4. Two sludge characteristics were studied: types of coagulant and textures of the suspended solid in raw water. The coagulant types are aluminium sulphate and polyaluminium chloride (PACl); the textures of the suspended solid are sand-based and clay-based. Efficiency of aluminium recovery at a pH of 2 was compared for different sludges obtained from water treatment plants in Taiwan. The results showed that efficiency of aluminium recovery from sludge containing clayey particles was higher than that from sludge containing sandy particles. As for the effect of coagulant types, the aluminium recovery efficiency for sludge using PACl ranged between 77% and 100%, whereas it ranged between 65% and 72% for sludge using aluminium sulphate as the coagulant. This means using PACl as the coagulant could result in higher recovery efficiency of coagulant and be beneficial for water treatment plants where renewable materials and waste reduction as the factors for making decisions regarding plant operations. However, other metals, such as manganese, could be released with aluminium during the acidification process and limit the use of the recovered coagulants. It is suggested that the recovered coagulants be used in wastewater treatment processes.

  2. Coagulation testing in the perioperative period.

    PubMed

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

    2014-09-01

    Perioperative coagulation management is a complex task that has a significant impact on the perioperative journey of patients. Anaesthesia providers play a critical role in the decision-making on transfusion and/or haemostatic therapy in the surgical setting. Various tests are available in identifying coagulation abnormalities in the perioperative period. While the rapidly available bedside haemoglobin measurements can guide the transfusion of red blood cells, blood product administration is guided by many in vivo and in vitro tests. The introduction of newer anticoagulant medications and the implementation of the modified in vivo coagulation cascade have given a new dimension to the field of perioperative transfusion medicine. A proper understanding of the application and interpretation of the coagulation tests is vital for a good perioperative outcome.

  3. Directional microwave applicator and methods

    NASA Technical Reports Server (NTRS)

    Fink, Patrick W. (Inventor); Lin, Greg Y. (Inventor); Chu, Andrew W. (Inventor); Dobbins, Justin A. (Inventor); Arndt, G. Dickey (Inventor); Ngo, Phong H. (Inventor)

    2008-01-01

    A miniature microwave antenna is disclosed which may be utilized for biomedical applications such as, for example, radiation induced hyperthermia through catheter systems. One feature of the antenna is that it possesses azimuthal directionality despite its small size. This directionality permits targeting of certain tissues while limiting thermal exposure of adjacent tissue. One embodiment has an outer diameter of about 0.095'' (2.4 mm) but the design permits for smaller diameters.

  4. Dust Coagulation in Protoplanetary Accretion Disks

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

    The time evolution of dust particles in circumstellar disk-like structures around protostars and young stellar objects is discussed. In particular, we consider the coagulation of grains due to collisional aggregation. The coagulation of the particles is calculated by solving numerically the non-linear Smoluchowski equation. The different physical processes leading to relative velocities between the grains are investigated. The relative velocities may be induced by Brownian motion, turbulence and drift motion. Starting from different regimes which can be identified during the grain growth we also discuss the evolution of dust opacities. These opacities are important for both the derivation of the circumstellar dust mass from submillimeter/millimeter continuum observations and the dynamical behavior of the disks. We present results of our numerical studies of the coagulation of dust grains in a turbulent protoplanetary accretion disk described by a time-dependent one-dimensional (radial) alpha-model. For several periods and disk radii, mass distributions of coagulated grains have been calculated. From these mass spectra, we determined the corresponding Rosseland mean dust opacities. The influence of grain opacity changes due to dust coagulation on the dynamical evolution of a protostellar disk is considered. Significant changes in the thermal structure of the protoplanetary nebula are observed. A 'gap' in the accretion disk forms at the very frontier of the coagulation, i.e., behind the sublimation boundary in the region between 1 and 5 AU.

  5. Coagulation algorithms with size binning

    NASA Technical Reports Server (NTRS)

    Statton, David M.; Gans, Jason; Williams, Eric

    1994-01-01

    The Smoluchowski equation describes the time evolution of an aerosol particle size distribution due to aggregation or coagulation. Any algorithm for computerized solution of this equation requires a scheme for describing the continuum of aerosol particle sizes as a discrete set. One standard form of the Smoluchowski equation accomplishes this by restricting the particle sizes to integer multiples of a basic unit particle size (the monomer size). This can be inefficient when particle concentrations over a large range of particle sizes must be calculated. Two algorithms employing a geometric size binning convention are examined: the first assumes that the aerosol particle concentration as a function of size can be considered constant within each size bin; the second approximates the concentration as a linear function of particle size within each size bin. The output of each algorithm is compared to an analytical solution in a special case of the Smoluchowski equation for which an exact solution is known . The range of parameters more appropriate for each algorithm is examined.

  6. Characterization and literature review of bowel perforation injuring using argon beam coagulation

    NASA Astrophysics Data System (ADS)

    Barnes, Kelli S.; Merchel, Renée. A.; Taylor, Kenneth D.

    2015-03-01

    INTRODUCTION: Argon Beam Coagulation (ABC®) technology is used in conjunction with the ConMed ABCFlex® Probe to provide non-contact hemostasis, coagulation, and tissue devitalization during endoscopic procedures. ABC provides a superficial tissue effect; however, there is a risk of bowel perforation. To better understand the settings that lead to perforation, this study reviews the literature and provides an ex vivo characterization of the ABCFlex Probe tissue effect at different settings when used at small distances. METHODS: Depth of thermal tissue effect was characterized to determine the effect of three parameters: power (W), distance from probe tip to tissue (mm) and application duration (s). 3 ABCFlex Probes were used to create 15 samples on ex vivo porcine small intestine for each combination of parameters. The depth of tissue effect for each sample was measured using a light microscope. RESULTS: Depth of tissue effect increases as power and application time increases. An increase of distance from the probe tip to the tissue results in a decrease in depth of tissue effect from a near contact to 1mm distance. Depth of tissue effect doesn't significantly change from 1mm to 3mm distance. CONCLUSION: ABCFlex Probe can be used to achieve hemostasis in endoscopic procedures. Increasing power and application time increases the depth of thermal effect while increasing distance from the probe time to the surface of the tissue decreases the depth of tissue effect.

  7. Characteristics of frozen colostrum thawed in a microwave oven

    SciTech Connect

    Jones, L.R.; Taylor, A.W.; Hines, H.C.

    1987-09-01

    Use of a microwave oven to thaw frozen colostrum was evaluated. Colostrum was collected from nine cows, four of which were immunized to produce specific colostral antibodies. Colostrum from each cow was frozen, subsequently thawed, and pooled. One-liter aliquots of the pooled colostrum were frozen and assigned randomly to three thawing treatments. Colostrum was thawed using one of three regimens: 10 min in a microwave oven at full power (650 W), 17 min in a microwave oven at half power (325 W), and 25 min in 45 degrees C water. Colostrum thawed in the microwave oven was slightly coagulated and had lower volume and total protein content than colostrum thawed in water. Casein and pH were not different among treatments. Both concentration and total content of immunoglobulin A were higher in the control than in microwave treatments. Neither amount nor concentration of immunoglobulin G and immunoglobulin M were different among treatments. Immunological activity, measured by a hemolytic test, was lower for microwave treatments than the control but did not differ between microwave treatments. Frozen colostrum thawed in a microwave oven should provide a reasonable source of colostrum when fresh high quality colostrum is not available.

  8. In Vivo Simulator for Microwave Treatment

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James R. (Inventor); Raffoul, George W. (Inventor); Karasack, Vincent G. (Inventor); Pacifico, Antonio (Inventor); Pieper, Carl F. (Inventor)

    2001-01-01

    Method and apparatus are provided for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue to treat ventricular tachycardia and other arrhythmias while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about 6 GHz. A computer simulation provides initial screening capabilities for an antenna such as antenna. frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In operation, microwave energy between about 1 GHz and 12 GHz is applied to monopole microwave radiator having a surface wave limiter. A test setup provides physical testing of microwave radiators to determine the temperature profile created in actual heart tissue or ersatz heart tissue. Saline solution pumped over the heart tissue with a peristaltic pump simulates blood flow. Optical temperature sensors disposed at various tissue depths within the heart tissue detect the temperature profile without creating any electromagnetic interference. The method may be used to produce a desired temperature profile in other body tissues reachable by catheter such as tumors and the like.

  9. Dysfunction in the coagulation system and schizophrenia

    PubMed Central

    Hoirisch-Clapauch, S; Amaral, O B; Mezzasalma, M A U; Panizzutti, R; Nardi, A E

    2016-01-01

    Although different hypotheses have been formulated to explain schizophrenia pathogenesis, the links between them are weak. The observation that five psychotic patients on chronic warfarin therapy for deep-vein thrombosis showed long-term remission of psychotic symptoms made us suspect that abnormalities in the coagulation pathway, specifically low tissue plasminogen activator (tPA) activity, could be one of the missing links. Our hypothesis is supported by a high prevalence of conditions affecting tPA activity in drug-naive schizophrenia, such as antiphospholipid antibodies, elevated cytokine levels, hyperinsulinemia and hyperhomocysteinemia. We recently screened a group of schizophrenia patients and controls for conditions affecting tPA activity. Free-protein S deficiency was highly prevalent among patients, but not found in controls. Free-protein S and functional protein C are natural anticoagulants that form complexes that inhibit tPA inhibitors. All participants had normal protein C levels, suggesting that protein S could have a role in schizophrenia, independent of protein C. Chronic patients and those studied during acute episodes had between three and six conditions affecting tPA and/or protein S activity, while patients in remission had up to two, which led us to postulate that multiple conditions affecting tPA and/or protein S activity could contribute to the full expression of schizophrenia phenotype. This paper describes the physiological roles of tPA and protein S, reviewing how their activity influences pathogenesis and comorbidity of schizophrenia. Next, it analyzes how activity of tPA and protein S is influenced by biochemical abnormalities found in schizophrenia. Last, it suggests future directions for research, such as studies on animal models and on therapeutic approaches for schizophrenia aiming at increasing tPA and protein S activity. PMID:26731441

  10. CpaA a novel protease from Acinetobacter baumannii clinical isolates deregulates blood coagulation.

    PubMed

    Tilley, Derek; Law, Robert; Warren, Sarah; Samis, John A; Kumar, Ayush

    2014-07-01

    Acinetobacter baumannii is an important nosocomial pathogen that displays high antibiotic resistance. It causes a variety of infections including pneumonias and sepsis which may result in disseminated intravascular coagulation. In this work, we identify and characterize a novel secreted, zinc-dependent, metallo-endopeptidase CpaA (coagulation targeting metallo-endopeptidase of Acinetobacter baumannii) which deregulates human blood coagulation in vitro and thus is likely to contribute to A. baumannii virulence. Three quarters of the clinical isolates tested (n = 16) had the cpaA gene; however, it was absent from two type strains, A. baumannii ATCC 17978 and A. baumannii ATCC 19606. The CpaA protein was purified from one clinical isolate and was able to cleave purified factor (F) V and fibrinogen and reduce the coagulation activity of FV in human plasma. CpaA-treated plasma showed reduced clotting activity in contact pathway-activated partial thromboplastin time (aPTT) assays, but increased clotting activity in tissue factor pathway prothrombin time (PT) assays. A significant portion of clinically relevant A. baumannii isolates secrete a protease which targets and deregulates the coagulation system.

  11. Coagulation factor V(A2440G) causes east Texas bleeding disorder via TFPIα.

    PubMed

    Vincent, Lisa M; Tran, Sinh; Livaja, Ruzica; Bensend, Tracy A; Milewicz, Dianna M; Dahlbäck, Björn

    2013-09-01

    The autosomal dominantly inherited east Texas bleeding disorder is linked to an A2440G variant in exon 13 of the F5 gene. Affected individuals have normal levels of coagulation factor V (FV) activity, but demonstrate inhibition of global coagulation tests. We demonstrated that the A2440G mutation causes upregulation of an alternatively spliced F5 transcript that results in an in-frame deletion of 702 amino acids of the large activation fragment, the B domain. The approximately 250-kDa FV isoform (FV-short), which can be fully activated by thrombin, is present in all A2440G carriers' plasma (n = 16). FV-short inhibits coagulation through an indirect mechanism by forming a complex with tissue factor pathway inhibitor-α (TFPIα), resulting in an approximately 10-fold increase in plasma TFPIα, suggesting that the TFPIα:FV-short complexes are retained in circulation. The TFPIα:FV-short complexes efficiently inhibit thrombin generation of both intrinsic and extrinsic coagulation pathways. These data demonstrate that the east Texas bleeding disorder-associated F5(A2440G) leads to the formation of the TFPIα:FV-short complex, which inhibits activation and propagation of coagulation.

  12. Coagulation factor VA2440G causes east Texas bleeding disorder via TFPIα

    PubMed Central

    Vincent, Lisa M.; Tran, Sinh; Livaja, Ruzica; Bensend, Tracy A.; Milewicz, Dianna M.; Dahlbäck, Björn

    2013-01-01

    The autosomal dominantly inherited east Texas bleeding disorder is linked to an A2440G variant in exon 13 of the F5 gene. Affected individuals have normal levels of coagulation factor V (FV) activity, but demonstrate inhibition of global coagulation tests. We demonstrated that the A2440G mutation causes upregulation of an alternatively spliced F5 transcript that results in an in-frame deletion of 702 amino acids of the large activation fragment, the B domain. The approximately 250-kDa FV isoform (FV-short), which can be fully activated by thrombin, is present in all A2440G carriers’ plasma (n = 16). FV-short inhibits coagulation through an indirect mechanism by forming a complex with tissue factor pathway inhibitor-α (TFPIα), resulting in an approximately 10-fold increase in plasma TFPIα, suggesting that the TFPIα:FV-short complexes are retained in circulation. The TFPIα:FV-short complexes efficiently inhibit thrombin generation of both intrinsic and extrinsic coagulation pathways. These data demonstrate that the east Texas bleeding disorder–associated F5A2440G leads to the formation of the TFPIα:FV-short complex, which inhibits activation and propagation of coagulation. PMID:23979162

  13. Clinical utility of biomarkers of endothelial activation and coagulation for prognosis in HIV infection

    PubMed Central

    Graham, Susan M; Mwilu, Regina; Liles, W Conrad

    2013-01-01

    Introduction: HIV infection is associated with vascular dysfunction and adverse cardiovascular outcomes. Our objective was to review the evidence regarding the clinical utility of endothelial activation and coagulation biomarkers for the prognosis of HIV-infected patients. Methods: We searched PubMed and Embase for publications using the keywords “HIV” or “HIV infection” and “endothelium” or “coagulation”. We reviewed reference lists and hand-searched for additional relevant articles. All clinical studies that enrolled non-pregnant, HIV-infected adults, measured biomarkers reflecting endothelial activation or coagulation, and prospectively evaluated their associations with vascular dysfunction or clinical outcomes were included. Results: Seventeen studies were identified that fulfilled the inclusion criteria, of which 11 investigated endothelial activation biomarkers and 12 investigated coagulation biomarkers. Biomarkers and outcomes varied widely across studies. Overall, published studies support an association between P-selectin and venous thromboembolism in HIV-infected patients, an association between tissue-type plasminogen activator and death, and associations between D-dimer and several clinical outcomes, including venous thromboembolism, cardiovascular disease, and all-cause mortality. Conclusions: Several studies have demonstrated associations between biomarkers of endothelial activation and coagulation and clinically important outcomes in HIV-1 infection. Additional large-scale prospective investigations to determine the utility of endothelial activation and coagulation biomarkers for risk stratification and prediction of adverse outcomes are clearly warranted. PMID:23732995

  14. Microwave processing of ceramics

    SciTech Connect

    Katz, J.D.

    1989-01-01

    This paper discusses the following topics on microwave processing of ceramics: Microwave-material interactions; anticipated advantage of microwave sintering; ceramic sintering; and ceramic joining. 24 refs., 4 figs. (LSP)

  15. Magnetic particle imaging of blood coagulation

    SciTech Connect

    Murase, Kenya Song, Ruixiao; Hiratsuka, Samu

    2014-06-23

    We investigated the feasibility of visualizing blood coagulation using a system for magnetic particle imaging (MPI). A magnetic field-free line is generated using two opposing neodymium magnets and transverse images are reconstructed from the third-harmonic signals received by a gradiometer coil, using the maximum likelihood-expectation maximization algorithm. Our MPI system was used to image the blood coagulation induced by adding CaCl{sub 2} to whole sheep blood mixed with magnetic nanoparticles (MNPs). The “MPI value” was defined as the pixel value of the transverse image reconstructed from the third-harmonic signals. MPI values were significantly smaller for coagulated blood samples than those without coagulation. We confirmed the rationale of these results by calculating the third-harmonic signals for the measured viscosities of samples, with an assumption that the magnetization and particle size distribution of MNPs obey the Langevin equation and log-normal distribution, respectively. We concluded that MPI can be useful for visualizing blood coagulation.

  16. [Investigation of coagulation time: PT and APTT].

    PubMed

    Ramakers, Christian; van der Heul, Cees; van Wijk, Eduard M

    2012-01-01

    The first case report describes an extremely prolonged activated partial thromboplastin time (APTT) in a patient with no history of increased bleeding tendency. Heparin use was excluded. The APTT mixing study combined with the medical history suggests a deficiency in one of the non-essential coagulation factors. This was confirmed by factor XII activity of <1%. The second case report describes a prolonged APTT in a patient with no history of increased bleeding tendency. The negative bleeding tendency in combination with a failure of the mixing study to correct the coagulation assay results suggests a factor inhibitor, most probably lupus anticoagulant. Indeed, the lupus anticoagulant was positive and the anti-cardiolipin antibody titre was also positive. Aberrations in the process of haemostasis can be efficiently screened using a platelet count, an APTT, a PT and a thorough physical examination combined with a thorough medical history taking. Common causes of prolonged PT and/or APTT are the use of oral anticoagulants or heparin, vitamin K deficiency and liver disease. Other causes include coagulation factor deficiencies, coagulation factor inhibitors and diffuse intravascular coagulation.

  17. Microrheological Coagulation Assay Exploiting Micromechanical Resonators.

    PubMed

    Padovani, Francesco; Duffy, James; Hegner, Martin

    2017-01-03

    Rheological measurements in biological liquids yield insights into homeostasis and provide information on important molecular processes that affect fluidity. We present a fully automated cantilever-based method for highly precise and sensitive measurements of microliter sample volumes of human blood plasma coagulation (0.009 cP for viscosity range 0.5-3 cP and 0.0012 g/cm(3) for density range 0.9-1.1 g/cm(3)). Microcantilever arrays are driven by a piezoelectric element, and resonance frequencies and quality factors of sensors that change over time are evaluated. A highly accurate approximation of the hydrodynamic function is introduced that correlates resonance frequency and quality factor of cantilever beams immersed in a fluid to the viscosity and density of that fluid. The theoretical model was validated using glycerol reference solutions. We present a surface functionalization protocol that allows minimization of unspecific protein adsorption onto cantilevers. Adsorption leads to measurement distortions and incorrect estimation of the fluid parameters (viscosity and density). Two hydrophilic terminated self-assembled monolayers (SAMs) sensor surfaces are compared to a hydrophobic terminated SAM coating. As expected, the hydrophobic modified surfaces induced the highest mass adsorption and could promote conformational changes of the proteins and subsequent abnormal biological activity. Finally, the activated partial thromboplastin time (aPTT) coagulation assay was performed, and the viscosity, density, and coagulation rate of human blood plasma were measured along with the standard coagulation time. The method could extend and improve current coagulation testing.

  18. Fibrinolysis and the control of blood coagulation.

    PubMed

    Chapin, John C; Hajjar, Katherine A

    2015-01-01

    Fibrin plays an essential role in hemostasis as both the primary product of the coagulation cascade and the ultimate substrate for fibrinolysis. Fibrinolysis efficiency is greatly influenced by clot structure, fibrinogen isoforms and polymorphisms, the rate of thrombin generation, the reactivity of thrombus-associated cells such as platelets, and the overall biochemical environment. Regulation of the fibrinolytic system, like that of the coagulation cascade, is accomplished by a wide array of cofactors, receptors, and inhibitors. Fibrinolytic activity can be generated either on the surface of a fibrin-containing thrombus, or on cells that express profibrinolytic receptors. In a widening spectrum of clinical disorders, acquired and congenital defects in fibrinolysis contribute to disease morbidity, and new assays of global fibrinolysis now have potential predictive value in multiple clinical settings. Here, we summarize the basic elements of the fibrinolytic system, points of interaction with the coagulation pathway, and some recent clinical advances.

  19. Fibrinolysis and the control of blood coagulation

    PubMed Central

    Chapin, John C.; Hajjar, Katherine A.

    2014-01-01

    Fibrin plays an essential role in hemostasis as both the primary product of the coagulation cascade and the ultimate substrate for fibrinolysis. Fibrinolysis efficiency is greatly influenced by clot structure, fibrinogen isoforms and polymorphisms, the rate of thrombin generation, the reactivity of thrombus-associated cells such as platelets, and the overall biochemical environment. Regulation of the fibrinolytic system, like that of the coagulation cascade, is accomplished by a wide array of cofactors, receptors, and inhibitors. Fibrinolytic activity can be generated either on the surface of a fibrin-containing thrombus, or on cells that express profibrinolytic receptors. In a widening spectrum of clinical disorders, acquired and congenital defects in fibrinolysis contribute to disease morbidity, and new assays of global fibrinolysis now have potential predictive value in multiple clinical settings. Here, we summarize the basic elements of the fibrinolytic system, points of interaction with the coagulation pathway, and some recent clinical advances. PMID:25294122

  20. Prostate cancer: beware of disseminated intravascular coagulation

    PubMed Central

    Desai, Mihir; John, Babbin; Evans, Gillian; Eddy, Ben

    2015-01-01

    Disseminated intravascular coagulation (DIC) is a pathological systemic condition resulting from aberrant activation of the coagulation system. It is characterised by the release and activation of procoagulants into the blood, with an associated consumption coagulopathy. Its association with solid and haematological malignancies is well described in literature. This case describes an elderly man, known to have prostate cancer, who following transurethral resection of the prostate developed DIC with haematuria, spontaneous ecchymoses and mucosal bleeding. Subsequent investigations revealed a prostate-specific antigen (PSA) >1000 µg/L, and staging CT showed multiple sclerotic metastatic lesions affecting the thoracic and lumbar vertebra, as well as infiltration into his left femur. Coagulation normalised with blood products and vitamin K within 1 week, and the patient responded to antiandrogen therapy with a reduction in pain and PSA on discharge. PMID:25819815

  1. Coagulation-membrane filtration of Chlorella vulgaris.

    PubMed

    Lee, Duu-Jong; Liao, Guan-Yu; Chang, Yin-Ru; Chang, Jo-Shu

    2012-03-01

    Filtration-based separation of Chlorella vulgaris, a species with excellent potential for CO(2) capture and lipid production, was investigated using a surface-modified hydrophilic polytetrafluoroethylene (PTFE) membrane. Coagulation using polyaluminum chloride (PACl) attained maximum turbidity removal at 200 mg L(-1) as Al(2)O(3). The membrane filtration flux at 1 bar increased as the PACl dose increased, regardless of overdosing in the coagulation stage. The filtered cake at the end of filtration tests peaked in solid content at 10 mg L(-1) as Al(2)O(3), reaching 34% w/w, roughly two times that of the original suspension. Differential scanning calorimetry (DSC) tests demonstrate that the cake with minimum water-solid binding strength produced the driest filter cake. Coagulation using 10 mg L(-1) PACl as Al(2)O(3), followed by PTFE membrane filtration at 1 bar, is an effective process for harvesting C. vulgaris from algal froth.

  2. Post-treatment of sanitary landfill leachate by coagulation-flocculation using chitosan as primary coagulant.

    PubMed

    Nascimento, Inara Oliveira do Carmo; Guedes, Ana Rosa Pinto; Perelo, Louisa Wessels; Queiroz, Luciano Matos

    2016-01-01

    Chitosan was chosen as an alternative primary coagulant in a complementary coagulation-flocculation treatment of sanitary landfill leachate with the aim of removing recalcitrant organic matter. In order to optimize the process conditions, central composite design and response surface methodology were applied. To evaluate the performance of the process using chitosan, we also carried out tests with aluminium sulphate (Al(2) (SO(4))(3).14 H(2)O) as coagulant. In addition, acute toxicity tests were carried using the duckweed Lemna minor and the guppy fish Poecilia reticulata as test organisms. The analytic hierarchy process was employed for selecting the most appropriate coagulant. Mean values of true colour removal efficiency of 80% and turbidity removal efficiency of 91.4% were reached at chitosan dosages of 960 mg L(-1) at pH 8.5. The acute toxicity tests showed that organisms were sensitive to all samples, mainly after coagulation-flocculation using chitosan. CE(50) for L. minor was not determined because there was no inhibition of the average growth rate and biomass production; LC(50) for P. reticulata was 23% (v v(-1)). Multi-criteria analysis showed that alum was the most appropriate coagulant. Therefore, chitosan as primary coagulant was not considered to be a viable alternative in the post-treatment of landfill leachate.

  3. Preparation of magnetic indole-3-acetic acid imprinted polymer beads with 4-vinylpyridine and β-cyclodextrin as binary monomer via microwave heating initiated polymerization and their application to trace analysis of auxins in plant tissues.

    PubMed

    Zhang, Yi; Li, Yuanwen; Hu, Yuling; Li, Gongke; Chen, Yueqin

    2010-11-19

    Auxin is a crucial phytohormone for precise control of growth and development of plants. Due to its low concentration in plant tissues which are rich in interfering substances, the accurate determination of auxins remains a challenge. In this paper, a new strategy for isolation and enrichment of auxins from plant tissues was obtained by the magnetic molecularly imprinted polymer (mag-MIP) beads, which were prepared by microwave heating initiated suspension polymerization using indole-3-acetic acid (IAA) as template. In order to obtain higher selective recognition cavities, an enhanced imprinting method based on binary functional monomers, 4-vinylpyridine (4-VP) and β-cyclodextrin (β-CD), was adopted for IAA imprinting. The morphological and magnetic characteristics of the mag-MIP beads were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy and vibrating sample magnetometry. A majority of resultant beads were within the size range of 80-150μm. Porous surface morphology and good magnetic property were observed. Furthermore, the mag-MIP beads fabricated with 4-VP and β-CD as binary functional monomers exhibited improved recognition ability to IAA, as compared with the mag-MIP beads prepared with the individual monomer separately. Competitive rebinding experiment results revealed that the mag-MIP beads exhibited a higher specific recognition for the template than the non-imprinted polymer (mag-NIP) beads. An extraction method by mag-MIP beads coupled with high performance liquid chromatography (HPLC) was developed for determination of IAA and indole-3-butyric acid (IBA) in plant tissues. Linear ranges for IAA and IBA were in the range of 7.00-100.0μgL(-1) and 10.0-100.0μgL(-1), and the detection limits were 3.9 and 7.4μgL(-1), respectively. The analytical performance was also estimated by seedlings or immature embryos samples from three different plant tissues, pea, rice and wheat. Recoveries were in the range of 70

  4. Computer-assisted interstitial laser coagulation for BPH

    NASA Astrophysics Data System (ADS)

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

    2001-06-01

    Interstitial laser thermotherapy is a minimally invasive surgical procedure that utilizes laser to coagulate and treat benign prostatic hyperplasia. This study explores the use of a computer-assisted interstitial laser coagulation system to aid surgeons in performing this procedure.

  5. Nanoparticle coagulation in fractionally charged and charge fluctuating dusty plasmas

    SciTech Connect

    Nunomura, Shota; Kondo, Michio; Shiratani, Masaharu; Koga, Kazunori; Watanabe, Yukio

    2008-08-15

    The kinetics of nanoparticle coagulation has been studied in fractionally charged and charge fluctuating dusty plasmas. The coagulation occurs when the mutual collision frequency among nanoparticles exceeds their charging and decharging/neutralization frequency. Interestingly, the coagulation is suppressed while a fraction (several percent) of nanoparticles are negatively charged in a plasma, in which stochastic charging plays an important role. A model is developed to predict a phase diagram of the coagulation and its suppression.

  6. Coagulation Activation in Children with Sickle Cell Disease Is Associated with Cerebral Small Vessel Vasculopathy

    PubMed Central

    Colombatti, Raffaella; De Bon, Emiliano; Bertomoro, Antonella; Casonato, Alessandra; Pontara, Elena; Omenetto, Elisabetta; Saggiorato, Graziella; Steffan, Agostino; Damian, Tamara; Cella, Giuseppe; Teso, Simone; Manara, Renzo; Rampazzo, Patrizia; Meneghetti, Giorgio; Basso, Giuseppe; Sartori, Maria Teresa; Sainati, Laura

    2013-01-01

    Background Thrombotic complications in Sickle Cell Disease (SCD) arise since infancy, but the role of the coagulation system in children has been poorly explored. To determine its role in the development of clinical complications in childhood we measured coagulation and endothelial parameters in children with SCD at steady state. Methods Markers of thrombin generation, fibrin dissolution and endothelial activation were evaluated in 38 children with SS-Sβ°, 6 with SC disease and 50 age and blood group matched controls. Coagulation variables were correlated with markers of hemolysis and inflammation, with the presence of cerebral and lung vasculopathy and with the frequency of clinical complications. Results SS-Sβ° patients presented higher levels of factor VIII, von Willebrand factor antigen (VWF:Ag) and collagen binding activity, tissue plasminogen activator antigen (t-PA:Ag), D-dimer, p-selectin, prothrombin fragment1+2 (F1+2) and lower ADAMTS-13:activity/VWF:Ag (p<0.05) compared to controls and SC patients. In SS-Sβ° patients coagulation variables correlated positively with markers of inflammation, hemolysis, and negatively with HbF (p<0.05). Patients with cerebral silent infarcts showed significant decrease in t-PA:Ag and ADAMTS-13 Antigen and a tendency toward higher D-dimer, F1+2, TAT compared to patients without them. D-dimer was associated with a six fold increased risk of cerebral silent infarcts. No correlation was found between coagulation activation and large vessel vasculopathy or other clinical events except for decreased t-PA:Ag in patients with tricuspid Rigurgitant Velocity >2.5m/sec. Conclusions SS-Sβ° disease is associated with extensive activation of the coagulation system at steady state since young age. ADAMTS-13 and t-PA:Ag are involved in the development of cerebral silent infarcts. PMID:24205317

  7. Microwave-assisted purge-and-trap extraction device coupled with gas chromatography and mass spectrometry for the determination of five predominant odors in sediment, fish tissues, and algal cells.

    PubMed

    Deng, Xuwei; Xie, Ping; Qi, Min; Liang, Gaodao; Chen, Jun; Ma, Zhimei; Jiang, Yan

    2012-01-06

    Off-flavors are among the most troublesome compounds in the environment worldwide. The lack of a viable theory for studying the sources, distribution, and effect of odors has necessitated the accurate measurement of odors from environmental compartments. A rapid and flexible microwave-assisted purge-and-trap extraction device for simultaneously determining five predominant odors, namely, dimethyltrisulfide, 2-methylisoborneol, geosmin, β-cyclocitral and β-ionone, from the primary sources and sinks is demonstrated. This instrument facilitates the extraction and concentration of odors from quite different matrices simultaneously. This device is a solvent-free automated system that does not require cleaning and is timesaving. The calibration curves of the five odor compounds showed good linearity in the range of 1-500 ng/L, with correlation coefficients above 0.999 (levels=7) and with residuals ranging from approximately 77% to 104%. The limits of detection (S/N=3) were below 0.15 ng/L in algae sample and 0.07 ng/g in sediment and fish tissue samples. The relative standard deviations were between 2.65% and 7.29% (n=6). Thus the proposed design is ready for rapid translation into a standard analytical tool and is useful for multiple applications in the analysis of off-flavors.

  8. Use of the diode laser (805 nm) and an angled fiber for coagulation/vaporization of the prostate in the dog

    NASA Astrophysics Data System (ADS)

    Bartels, Kenneth E.; Stair, Ernest L.; Dickey, D. Thomas; Hurd, John S.; Powell, Ronald; Schafer, Steven A.; Nordquist, Robert E.; Willis, Randall J.; Hults, Donald F.

    1996-05-01

    This study evaluates tissue coagulation and ablation effects in the prostate gland of the canine model when a diode laser (805 nm-Diomed 25R-Surgimedics/ESP, The Woodlands, Texas) and an angled fiber configuration (1000 (mu) 20 degree bent-Surgimedics/ESP, The Woodlands, Texas were used at specified power densities. Comparisons of therapeutic modalities included animals treated with noncontact coagulation alone, contact ablation alone, and noncontact coagulation and contact ablation in combination. The principal objective was to validate the effectiveness of coagulating prostatic tissue in a noncontact mode at a lower power, followed immediately with contact ablation of the prostatic urethra at a higher energy level. Applying laser energy with the fiber tip in noncontact mode created a deeper zone of coagulative necrosis with an increased level of cellular destruction (lower power 15 - 20 watts delivered to four quadrants for 200 seconds/quadrant) than did higher power modalities alone. An increased luminal diameter, which prevented immediate postoperative urodynamic abnormalities (stranguria, dysuria, and severe hematuria) in this model, was produced by ablating the prostatic urethra with the fiber tip in a contact mode (higher power: 23 - 60 watts for an additional 120 - 200 seconds for the ablative process) immediately following the coagulative procedure. Additionally, semen evaluations performed before and after laser surgery (8 weeks after coagulation/ablation) were performed on one dog and found to be normal with respect to number of spermatozoa and motility.

  9. 21 CFR 864.5400 - Coagulation instrument.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Coagulation instrument. 864.5400 Section 864.5400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology Devices §...

  10. Roles for vitamin K beyond coagulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent interest in vitamin K has been motivated by evidence of physiological roles beyond that of coagulation. Vitamin K and vitamin K-dependent proteins may be involved in regulation of calcification, energy metabolism, and inflammation. However, the evidence for many of these proposed roles in the...

  11. 21 CFR 864.5400 - Coagulation instrument.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Coagulation instrument. 864.5400 Section 864.5400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...) Classification. Class II (performance standards)....

  12. 21 CFR 864.5400 - Coagulation instrument.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Coagulation instrument. 864.5400 Section 864.5400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology Devices §...

  13. 21 CFR 864.5400 - Coagulation instrument.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Coagulation instrument. 864.5400 Section 864.5400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology Devices §...

  14. 21 CFR 864.5400 - Coagulation instrument.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Coagulation instrument. 864.5400 Section 864.5400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Automated and Semi-Automated Hematology Devices §...

  15. Milestones and perspectives in coagulation and hemostasis.

    PubMed

    Lippi, Giuseppe; Favaloro, Emmanuel J; Franchini, Massimo; Guidi, Gian Cesare

    2009-02-01

    Hemostasis is traditionally defined as the physiologic process whereby bleeding is antagonized and possibly stopped to minimize blood loss. The first medical description of the clinical and inherited features of hemostasis can be dated back more than 1000 years, when Abu al-Qasim Khalaf ibn 'Abbas al-Andalusi al-Zahrawi' medical treatise provided some initial insights into this puzzling process. Since then, continuous and revolutionary scientific developments have contributed to decoding several aspects of this intricate but essential physiologic phenomenon, providing a reliable model to explain the leading mechanisms involved. Although the point at which bleeding stops is commonly referred to as "coagulation," blood coagulation is actually only one part of a two-part hemostatic process that develops through sequential steps referred to as primary and secondary hemostasis. Throughout its activation and development, the coagulation cascade is strictly regulated by a series of natural inhibitors, which prevent unnecessary and excessive clotting. The aim of this article is to provide a concise overview of the major discoveries and past and current perspectives in coagulation and hemostasis.

  16. Different Recovery Profiles of Coagulation Factors, Thrombin Generation, and Coagulation Function After Hemorrhagic Shock in Pigs

    DTIC Science & Technology

    2012-06-06

    Different recovery profiles of coagulation factors, thrombin generation, and coagulation function after hemorrhagic shock in pigs Wenjun Z. Martini ...Defense. Address for reprints: Wenjun Z. Martini , PhD, The US Army Institute of Surgical Research, 3698 Chambers Pass, Ft. Sam Houston, San Antonio, TX...ELEMENT NUMBER 6. AUTHOR(S) Martini W. Z., Cortez D. S., Dubick M. A., Blackbourne L. H., 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7

  17. Dynamic analysis of coagulation of low turbidity water sources using Al- and Fe-based coagulants.

    PubMed

    Ebie, K; Kawaguchi, T; Yamaguchi, D

    2006-01-01

    The direct filtration system is widely used in the treatment of source waters with low and stable turbidity. We have previously indicated the importance of optimizing agitation strength GR and time TR in rapid mixing tanks in order to decrease filter head loss and treated water turbidity in direct filtration. In the present study, we employ a batch-type coagulation experimental apparatus that incorporates a high-sensitivity particle counter, where the particulate concentrations are measured continuously after injection of coagulant, in order to clarify the fundamental coagulation and microfloc formation dynamics. Specifically, it is shown that, after injection of the coagulant, coagulation and microfloc formation occur through distinct periods: an agglomeration preparation period, followed by an agglomeration progression period, and then finally an agglomeration stabilization period, and that optimization of the GR value is the most important consideration, although both the coagulant concentration and GR influence the time at which agglomeration begins in the preparatory period, the time at which agglomeration stabilizes after the progression period, and the concentration of initial particles with diameters of 1-3 microm at completion of agglomeration.

  18. Enhanced coagulation for improving coagulation performance and reducing residual aluminum combining polyaluminum chloride with diatomite.

    PubMed

    Hu, Wenchao; Wu, Chunde

    2016-01-01

    The feasibility of using enhanced coagulation, which combined polyaluminum chloride (PAC) with diatomite for improving coagulation performance and reducing the residual aluminum (Al), was discussed. The effects of PAC and diatomite dosage on the coagulation performance and residual Al were mainly investigated. Results demonstrated that the removal efficiencies of turbidity, dissolved organic carbon (DOC), and UV254 were significantly improved by the enhanced coagulation, compared with PAC coagulation alone. Meaningfully, the five forms of residual Al (total Al (TAl), total dissolved Al (TDAl), dissolved organic Al (DOAl), dissolved monomeric Al (DMAl), and dissolved organic monomeric Al (DOMAl)) all had different degrees of reduction in the presence of diatomite and achieved the lowest concentrations (0.185, 0.06, 0.053, 0.014, and 0 mg L(-1), respectively) at a PAC dose of 15 mg L(-1) and diatomite dose of 40 mg L(-1). In addition, when PAC was used as coagulant, the majority of residual Al existed in dissolved form (about 31.14-70.16%), and the content of DOMAl was small in the DMAl.

  19. Novel Ion-Exchange Coagulants Remove More Low Molecular Weight Organics than Traditional Coagulants.

    PubMed

    Zhao, Huazhang; Wang, Lei; Hanigan, David; Westerhoff, Paul; Ni, Jinren

    2016-04-05

    Low molecular weight (MW) charged organic matter is poorly removed by conventional coagulants but contributes to disinfection byproduct formation during chlorination of drinking waters. We hypothesized that CIEX, a new Al-based hybrid coagulant with ion-exchange functional groups, would be new mechanistic approach to remove low MW organic matter during coagulation and would perform better than polyaluminum chloride (PACl) or metal-salt based coagulants. We measured coagulation performance using dissolved organic carbon (DOC) in a high hardness surface water. CIEX achieved excellent turbidity removal and removed 20% to 46% more DOC than FeCl3, Al2(SO4)3, or PACl, depending on dose. The improved DOC removal was attributable to better removal of low MW organic matter (<2 kDa). We further studied removal mechanisms in a model water containing a low MW organic acid (salicylic acid (SA)). CIEX achieved high removal of organic acids (>90% of SA) independent of pH, whereas removal by metal salts was lower (<15%) and was strongly pH dependent. CIEX ion-exchange capability is facilitated by its covalently bound quaternary ammonium group, which conventional coagulants lack. Plus, unlike other cationic polymers that react with chloramines to form N-nitrosodimethylamine (NDMA), CIEX has a low molar yield (9.3 × 10(-7) mol NDMA per mol CIEX-N).

  20. Study on the removal of acid dyes using chitosan as a natural coagulant/coagulant aid.

    PubMed

    Zonoozi, M H; Alavi Moghaddam, M R; Arami, M

    2011-01-01

    Chitosan was selected as a natural coagulating agent for the removal of acid dyes (Acid Blue 292; AB292, and Acid Red 398; AR398) from dye-containing solutions. The study was organised in two phases. In phase 1, chitosan was used alone as a natural coagulant for the removal of the dyes. For this purpose, the effect of different parameters including pH, chitosan dosage and initial dye concentration on the dye removal efficiency was examined. In phase 2 of the study, the application of chitosan as a natural coagulant aid in conjunction with polyaluminium chloride (PAC) was assessed. According to the results of phase 1, the best removal efficiencies occurred in an acidic pH range (less than 6) for both of the dyes. Also, excellent dye removal results (about 90%) were achieved with relatively low dosages of chitosan (30-35 mg L(-1) for AB292 and 50-60 mg L(-1) for AR398). However, the initial concentration of the dyes severely influenced the coagulation performance of chitosan, which can constrain the performance of chitosan as a natural coagulant. On the basis of the results of phase 2, chitosan, as a natural coagulant aid, noticeably enhanced the dye removal efficiency of PAC, especially in the case of AB292. Small amounts of chitosan (3 or 5 mg L(-1)) enhanced the dye removal efficiency of PAC up to 2.5 times for AB292.

  1. Resuscitation and coagulation in the severely injured trauma patient

    PubMed Central

    Midwinter, Mark J.; Woolley, Tom

    2011-01-01

    Developments in the resuscitation of the severely injured trauma patient in the last decade have been through the increased understanding of the early pathophysiological consequences of injury together with some observations and experiences of recent casualties of conflict. In particular, the recognition of early derangements of haemostasis with hypocoagulopathy being associated with increased mortality and morbidity and the prime importance of tissue hypoperfusion as a central driver to this process in this population of patients has led to new resuscitation strategies. These strategies have focused on haemostatic resuscitation and the development of the ideas of damage control resuscitation and damage control surgery continuum. This in turn has led to a requirement to be able to more closely monitor the physiological status, of major trauma patients, including their coagulation status, and react in an anticipatory fashion. PMID:21149355

  2. Viscoelasticity and Ultrastructure in Coagulation and Inflammation: Two Diverse Techniques, One Conclusion.

    PubMed

    Swanepoel, Albe C; Nielsen, Vance G; Pretorius, Etheresia

    2015-08-01

    The process of blood clotting has been studied for centuries. A synopsis of current knowledge pertaining to haemostasis and the blood components, including platelets and fibrin networks which are closely involved in coagulation, are discussed. Special emphasis is placed on tissue factor (TF), calcium and thrombin since these components have been implicated in both the coagulation process and inflammation. Analysis of platelets and fibrin morphology indicate that calcium, tissue factor and thrombin at concentrations used during viscoelastic analysis (with thromboelastography or TEG) bring about alterations in platelet and fibrin network ultrastructure, which is similar to that seen in inflammation. Scanning electron microscopy indicated that, when investigating platelet structure in disease, addition of TF, calcium or thrombin will mask disease-induced alterations associated with platelet activation. Therefore, washed platelets without any additives is preferred for morphological analysis. Furthermore, morphological and viscoelastic analysis confirmed that thrombin activation is the preferred method of fibrin activation when investigating fibrin network ultrastructure.

  3. Microwave ablation of hepatocellular carcinoma

    PubMed Central

    Poggi, Guido; Tosoratti, Nevio; Montagna, Benedetta; Picchi, Chiara

    2015-01-01

    Although surgical resection is still the optimal treatment option for early-stage hepatocellular carcinoma (HCC) in patients with well compensated cirrhosis, thermal ablation techniques provide a valid non-surgical treatment alternative, thanks to their minimal invasiveness, excellent tolerability and safety profile, proven efficacy in local disease control, virtually unlimited repeatability and cost-effectiveness. Different energy sources are currently employed in clinics as physical agents for percutaneous or intra-surgical thermal ablation of HCC nodules. Among them, radiofrequency (RF) currents are the most used, while microwave ablations (MWA) are becoming increasingly popular. Starting from the 90s’, RF ablation (RFA) rapidly became the standard of care in ablation, especially in the treatment of small HCC nodules; however, RFA exhibits substantial performance limitations in the treatment of large lesions and/or tumors located near major heat sinks. MWA, first introduced in the Far Eastern clinical practice in the 80s’, showing promising results but also severe limitations in the controllability of the emitted field and in the high amount of power employed for the ablation of large tumors, resulting in a poor coagulative performance and a relatively high complication rate, nowadays shows better results both in terms of treatment controllability and of overall coagulative performance, thanks to the improvement of technology. In this review we provide an extensive and detailed overview of the key physical and technical aspects of MWA and of the currently available systems, and we want to discuss the most relevant published data on MWA treatments of HCC nodules in regard to clinical results and to the type and rate of complications, both in absolute terms and in comparison with RFA. PMID:26557950

  4. Unidentified coagulation disorders in post-tonsillectomy hemorrhage.

    PubMed

    Windfuhr, Jochen P; Chen, Yue-Shih; Remmert, Stephan

    2004-01-01

    We conducted a retrospective study of 6,966 patients who had undergone tonsillectomy or adenotonsillectomy to evaluate the incidence and clinical features of previously unidentified coagulation disorders in patients who experienced postoperative hemorrhage (n = 201). We found that post-tonsillectomy hemorrhage secondary to unidentified coagulation disorders is extremely rare. However, normal coagulation values and an insignificant history do not rule out coagulation disorders. If diffuse, persistent, and bilateral bleeding is not related to arterial hypertension, dissection technique, or local infection, a rapid and detailed analysis of coagulation factors should be considered.

  5. Cardiovascular and blood coagulative effects of pulmonary zinc exposure

    SciTech Connect

    Gilmour, Peter S.; Nyska, Abraham; Schladweiler, Mette C.; McGee, John K.; Wallenborn, J. Grace; Richards, Judy H.; Kodavanti, Urmila P. . E-mail: kodavanti.urmila@epa.gov

    2006-02-15

    Cardiovascular damage induced by pulmonary exposure to environmental chemicals can result from direct action or, secondarily from pulmonary injury. We have developed a rat model of pulmonary exposure to zinc to demonstrate cardiac, coagulative, and fibrinolytic alterations. Male Wistar Kyoto rats were instilled intratracheally with saline or zinc sulfate, 131 {mu}g/kg (2 {mu}mol/kg); the alterations were determined at 1, 4, 24, and 48 h postexposure. High-dose zinc enabled us to show changes in circulating levels of zinc above normal and induce significant pulmonary inflammation/injury such that cardiac impairments were likely. At 1-24 h postexposure, plasma levels of zinc increased to nearly 20% above the base line. Significant pulmonary inflammation and injury were determined by analysis of bronchoalveolar lavage fluid and histopathology in zinc-exposed rats at all time points. Starting at 4 h postexposure, pulmonary damage was accompanied by persistently increased gene expressions of tissue factor (TF) and plasminogen activator-inhibitor-1 (PAI-1), but not thrombomodulin (TM). Cardiac tissues demonstrated similar temporal increases in expressions of TF, PAI-1, and TM mRNA following pulmonary instillation of zinc. In contrast to extensive pulmonary edema and inflammation, only mild, and focal acute, myocardial lesions developed in a few zinc-exposed rats; no histological evidence showed increased deposition of fibrin or disappearance of troponin. At 24 and 48 h postexposure to zinc, increases occurred in levels of systemic fibrinogen and the activated partial thromboplastin time. These data suggest that cardiovascular blood coagulation impairments are likely following pulmonary zinc exposure and associated pulmonary injury and inflammation.

  6. Microwave hematoma detector

    DOEpatents

    Haddad, Waleed S.; Trebes, James E.; Matthews, Dennis L.

    2001-01-01

    The Microwave Hematoma Detector is a non-invasive device designed to detect and localize blood pooling and clots near the outer surface of the body. While being geared towards finding sub-dural and epi-dural hematomas, the device can be used to detect blood pooling anywhere near the surface of the body. Modified versions of the device can also detect pneumothorax, organ hemorrhage, atherosclerotic plaque in the carotid arteries, evaluate perfusion (blood flow) at or near the body surface, body tissue damage at or near the surface (especially for burn assessment) and be used in a number of NDE applications. The device is based on low power pulsed microwave technology combined with a specialized antenna, signal processing/recognition algorithms and a disposable cap worn by the patient which will facilitate accurate mapping of the brain and proper function of the instrument. The invention may be used for rapid, non-invasive detection of sub-dural or epi-dural hematoma in human or animal patients, detection of hemorrhage within approximately 5 cm of the outer surface anywhere on a patient's body.

  7. Scanning microwave-induced thermoacoustic tomography: signal, resolution, and contrast.

    PubMed

    Ku, G; Wang, L V

    2001-01-01

    Scanning thermoacoustic tomography was explored in the microwave region of the electromagnetic spectrum. Short microwave pulses were used to induce acoustic waves by thermoelastic expansion in biological tissues. Cross sections of tissue samples were imaged by a linear scan of the samples while a focused ultrasonic transducer detected the time-resolved thermoacoustic signals. Based on the microwave-absorption properties of normal and cancerous breast tissues, the piezoelectric signals in response to the thermoacoustic contrast were investigated over a wide range of electromagnetic frequencies and depths of tumor locations. The axial resolution is related to the temporal profile of the microwave pulses and to the impulse response of the ultrasonic transducer. The lateral resolution is related to the numerical aperture of the ultrasonic transducer as well as to the frequency spectra of the piezoelectric signals in the time window corresponding to the axial resolution. Gain compensation, counteracting the microwave attenuation, was applied to enhance the image contrast.

  8. Coagulating activity of the blood, vascular wall, and myocardium under hypodynamia conditions

    NASA Technical Reports Server (NTRS)

    Petrovskiy, B. V. (Editor); Chazov, E. I. (Editor); Andreyev, S. V. (Editor)

    1980-01-01

    In order to study the effects of hypodynamia on the coagulating properties of the blood, vascular wall, and myocardium, chinchilla rabbits were kept for varying periods in special cages which restricted their movements. At the end of the experiment, blood samples were taken and the animals were sacrificed. Preparations were made from the myocardium venae cavae, and layers of the aorta. Two resultant interrelated and mutually conditioned syndromes were discovered: thrombohemorrhagic in the blood and hemorrago-thrombotic in the tissues.

  9. Spatial Propagation and Localization of Blood Coagulation Are Regulated by Intrinsic and Protein C Pathways, Respectively

    PubMed Central

    Panteleev, Mikhail A.; Ovanesov, Mikhail V.; Kireev, Dmitrii A.; Shibeko, Aleksei M.; Sinauridze, Elena I.; Ananyeva, Natalya M.; Butylin, Andrey A.; Saenko, Evgueni L.; Ataullakhanov, Fazoil I.

    2006-01-01

    Blood coagulation in vivo is a spatially nonuniform, multistage process: coagulation factors from plasma bind to tissue factor (TF)-expressing cells, become activated, dissociate, and diffuse into plasma to form enzymatic complexes on the membranes of activated platelets. We studied spatial regulation of coagulation using two approaches: 1), an in vitro experimental model of clot formation in a thin layer of plasma activated by a monolayer of TF-expressing cells; and 2), a computer simulation model. Clotting in factor VIII- and factor XI-deficient plasmas was initiated normally, but further clot elongation was impaired in factor VIII- and, at later stages, in factor XI-deficient plasma. The data indicated that clot elongation was regulated by factor Xa formation by intrinsic tenase, whereas factor IXa was formed by extrinsic tenase on activating cells and diffused into plasma, thus sustaining clot growth. Far from the activating cells, additional factor IXa was produced by factor XIa. Exogenously added TF had no effect on the clot growth rate, suggesting that plasma TF does not contribute significantly to the clot propagation process in a reaction-diffusion system without flow. Addition of thrombomodulin at 3–100 nM caused dose-dependent termination of clot elongation with a final clot size of 2–0.2 mm. These results identify roles of specific coagulation pathways at different stages of spatial clot formation (initiation, elongation, and termination) and provide a possible basis for their therapeutic targeting. PMID:16326897

  10. The role of platelets in coagulation dysfunction in xenotransplantation, and therapeutic options.

    PubMed

    Iwase, Hayato; Ezzelarab, Mohamed B; Ekser, Burcin; Cooper, David K C

    2014-01-01

    Xenotransplantation could resolve the increasing discrepancy between the availability of deceased human donor organs and the demand for transplantation. Most advances in this field have resulted from the introduction of genetically engineered pigs, e.g., α1,3-galactosyltransferase gene-knockout (GTKO) pigs transgenic for one or more human complement-regulatory proteins (e.g., CD55, CD46, CD59). Failure of these grafts has not been associated with the classical features of acute humoral xenograft rejection, but with the development of thrombotic microangiopathy in the graft and/or consumptive coagulopathy in the recipient. Although the precise mechanisms of coagulation dysregulation remain unclear, molecular incompatibilities between primate coagulation factors and pig natural anticoagulants exacerbate the thrombotic state within the xenograft vasculature. Platelets play a crucial role in thrombosis and contribute to the coagulation disorder in xenotransplantation. They are therefore important targets if this barrier is to be overcome. Further genetic manipulation of the organ-source pigs, such as pigs that express one or more coagulation-regulatory genes (e.g., thrombomodulin, endothelial protein C receptor, tissue factor pathway inhibitor, CD39), is anticipated to inhibit platelet activation and the generation of thrombus. In addition, adjunctive pharmacologic anti-platelet therapy may be required. The genetic manipulations that are currently being tested are reviewed, as are the potential pharmacologic agents that may prove beneficial.

  11. Total microwave processing using microwave technologies

    SciTech Connect

    Walter, P.J.; Kingston, H.M.

    1995-12-31

    The implementation of total microwave processing of samples involves all processes after the collection of a sample up to but not including the analysis. These processes are often time consuming and a primary source of critical analytical errors. The use of microwave technology has been shown to improve sample digestion while also reducing contamination. However, microwave technology can also be used in the preparation of representative samples and matrix modifications; essentially total sample preparation. The concept of total microwave processing will be discussed as applied to the routine analysis of samples according to proposed Environmental Protection Agency Method 3052. This method requires microwave digestion and provides for several methods of post-digestion removal of hydrofluoric acid. Microwave technologies will be shown to efficiently dry, digest, and perform matrix modifications.

  12. Blood coagulation and fibrinolysis in aortic valve stenosis: links with inflammation and calcification.

    PubMed

    Natorska, J; Undas, A

    2015-08-01

    Aortic valve stenosis (AS) increasingly afflicts our aging population. However, the pathobiology of the disease is still poorly understood and there is no effective pharmacotherapy for treating those at risk for clinical progression. The progression of AS involves complex inflammatory and fibroproliferative processes that resemble to some extent atherosclerosis. Accumulating evidence indicates that several coagulation proteins and its inhibitors, including tissue factor, tissue factor pathway inhibitor, prothrombin, factor XIII, von Willebrand factor, display increased expression within aortic stenotic valves, predominantly on macrophages and myofibroblasts around calcified areas. Systemic impaired fibrinolysis, along with increased plasma and valvular expression of plasminogen activator inhibitor-1, has also been observed in patients with AS in association with the severity of the disease. There is an extensive cross-talk between inflammation and coagulation in stenotic valve tissue which contributes to the calcification and mineralisation of the aortic valve leaflets. This review summarises the available data on blood coagulation and fibrinolysis in AS with the emphasis on their interactions with inflammation and calcification.

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

    PubMed

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

    2015-01-01

    Chitosan is a potential substitute for traditional aluminium salts in water treatment systems. This study compared the characteristics of humic acid (HA) removal by using acid-soluble chitosan, water-soluble chitosan, and coagulant mixtures of chitosan with aluminium sulphate (alum) or polyaluminium chloride (PACl). In addition, we evaluated their respective coagulation efficiencies at various coagulant concentrations, pH values, turbidities, and hardness levels. Furthermore, we determined the size and settling velocity of flocs formed by these coagulants to identify the major factors affecting HA coagulation. The coagulation efficiency of acid- and water-soluble chitosan for 15 mg/l of HA was 74.4% and 87.5%, respectively. The optimal coagulation range of water-soluble chitosan (9-20 mg/l) was broader than that of acid-soluble chitosan (4-8 mg/l). Notably, acid-soluble chitosan/PACl and water-soluble chitosan/alum coagulant mixtures exhibited a higher coagulation efficiency for HA than for PACl or alum alone. Furthermore, these coagulant mixtures yielded an acceptable floc settling velocity and savings in both installation and operational expenses. Based on these results, we confidently assert that coagulant mixtures with a 1:1 mass ratio of acid-soluble chitosan/PACl and water-soluble chitosan/alum provide a substantially more cost-effective alternative to using chitosan alone for removing HA from water.

  14. MICROWAVE SOLID-STATE GENERATORS.

    DTIC Science & Technology

    RADIOFREQUENCY GENERATORS , *SEMICONDUCTOR DIODES, *TRANSISTORS, MICROWAVE EQUIPMENT, X BAND, FREQUENCY MULTIPLIERS, MICROWAVE OSCILLATORS, CIRCUITS, BROADBAND, NARROWBAND, RADIOFREQUENCY POWER, TRANSISTOR AMPLIFIERS.

  15. Microwave generator for scientific and medical applications

    NASA Astrophysics Data System (ADS)

    Surducan, V.; Surducan, E.; Ciupa, R.; Neamtu, C.

    2012-02-01

    Nowadays power microwave radiation is widely used in medical applications as hyperthermia, diathermy or ablation and for scientific applications such as plasma generation, digestion, or as a catalyst in green chemistry. Nevertheless, designing a suitably adapted microwave generator that meets both the scientific and the more restrictive medical criteria remains a difficult task. We present here a simplified approach in designing such a microwave generator, according to the IEC60601 medical standard. The generator, based on a continuous wave (CW) magnetron, is coupled via a TE10 waveguide to feed either a hyperthermia applicator or a reactor chamber. Microwave interactions with the probe (or the tissue) depend strongly on the magnetron's power supply parameters and the impedance match of the entire microwave circuit. Any unmatched elements (magnetron to waveguide, waveguide to applicator, applicator to patient) give rise to a large voltage standing wave ratio (VSWR) which loads the generator with a surplus energy, converted to heat. Extra heating of the magnetron will deteriorate the amplitude of the generated microwave power field. We show here that, by using a proprietary patented temperature sensor sheet, we were able to detect and improve the impedance matching of the microwave circuit.

  16. Blood coagulation disorders in septic patients.

    PubMed

    Knoebl, Paul

    2010-03-01

    Host defense and blood coagulation are tightly connected and interacting systems, necessary for the integrity of an organism. Complex mechanisms regulate the intensity of a host response to invading pathogens or other potentially dangerous situations. Under regular conditions, this response is limited in time and located to the site of injury. Sometimes, however, systemic host response is overwhelming and disproportional and causes damage, not cure. Dependent on the genetical predisposition of the host, its current immunocompetence, or the type of injury, the reaction leads to the clinical picture of the different degrees of sepsis. Septic organ dysfunction is caused by intravascular fibrin deposition as a result of coagulation activation, anticoagulant breakdown, and shut down of fibrinolysis. This article describes the major pathophysiologic reactions in these situations and presents www.SepDIC.eu, an online tool on sepsis and associated coagulopathy.

  17. Coagulation of dust particles in a plasma

    NASA Technical Reports Server (NTRS)

    Horanyi, M.; Goertz, C. K.

    1990-01-01

    The electrostatic charge of small dust grains in a plasma in which the temperature varies in time is discussed, pointing out that secondary electron emission might introduce charge separation. If the sign of the charge on small grains is opposite to that on big ones, enhanced coagulation can occur which will affect the size distribution of grains in a plasma. Two scenarios where this process might be relevant are considered: a hot plasma environment with temperature fluctuations and a cold plasma environment with transient heating events. The importance of the enhanced coagulation is uncertain, because the plasma parameters in grain-producing environments such as a molecular cloud or a protoplanetary disk are not known. It is possible, however, that this process is the most efficient mechanism for the growth of grains in the size range of 0.1-500 microns.

  18. Microwave Medical Treatment Apparatus and Method

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Ngo, Phong H. (Inventor); Carl, James R. (Inventor); George, W. Rflfoul (Inventor)

    2005-01-01

    Methods, simulations, and apparatus are provided that may be utilized for medical treatments which are especially suitable for treatment of benign prostatic hyperplasia (BPH). In a preferred embodiment, a plurality of separate microwave antennas are utilized to heat prostatic tissue to promote necrosing of the prostatic tissue that relieves the pressure of the prostatic tissue against the urethra as the body reabsorbs the necrosed or dead tissue. By utilizing constructive and destructive interference of the microwave transmission, the energy can be deposited on the tissues to be necrosed while protecting other tissues such as the urethra. Saline injections to alter the conductivity of the tissues may also be used to further focus the energy deposits. A computer simulation is Provided that can be used to Predict the resulting temperature profile produced in the prostatic tissue. By changing the various control features of one or more catheters and the methods of applying microwave energy, a temperature profile can be predicted and produced that is similar to the temperature profile desired for the particular patient.

  19. Patterned retinal coagulation with a scanning laser

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

    Pan-retinal photocoagulation in patients with diabetic retinopathy typically involves application of more than 1000 laser spots; often resulting in physician fatigue and patient discomfort. We present a semi-automated patterned scanning laser photocoagulator that rapidly applies predetermined patterns of lesions; thus, greatly improving the comfort, efficiency and precision of the treatment. Patterns selected from a graphical user interface are displayed on the retina with an aiming beam, and treatment can be initiated and interrupted by depressing a foot pedal. To deliver a significant number of burns during the eye's fixation time, each pulse should be considerably shorter than conventional 100ms pulse duration. We measured coagulation thresholds and studied clinical and histological outcomes of the application of laser pulses in the range of 1-200ms in pigmented rabbits. Laser power required for producing ophthalmoscopically visible lesions with a laser spot of 132μm 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.

  20. Development of the selective coagulation process

    SciTech Connect

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

    1992-07-01

    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.

  1. Mouse tissue fixation.

    PubMed

    Cardiff, Robert D; Miller, Claramae H; Munn, Robert J

    2014-05-01

    One of the primary goals of fixation is to stop postmortem changes that degrade the tissue and allow optimal preservation of morphologic and cytological detail as well as nucleic acid integrity. Following death, tissues soon undergo autolysis, and if organisms from the gastrointestinal, urinary, or respiratory tracts are present, their colonization can soon cause putrefaction. Time is of the essence because warmer temperatures accelerate both types of degradation. Placing the tissue into a fixative stops the postmortem changes. Fixatives have their effect on tissue by cross-linking, coagulation, or a combination of both. This article outlines the basic tissue fixation procedure and offers guidance on choosing an appropriate fixative, the timing and duration of fixation, sample storage, and quality issues.

  2. Microwave Workshop for Windows.

    ERIC Educational Resources Information Center

    White, Colin

    1998-01-01

    "Microwave Workshop for Windows" consists of three programs that act as teaching aid and provide a circuit design utility within the field of microwave engineering. The first program is a computer representation of a graphical design tool; the second is an accurate visual and analytical representation of a microwave test bench; the third…

  3. Microwave Radiometer (MWR) Handbook

    SciTech Connect

    Morris, VR

    2006-08-01

    The Microwave Radiometer (MWR) provides time-series measurements of column-integrated amounts of water vapor and liquid water. The instrument itself is essentially a sensitive microwave receiver. That is, it is tuned to measure the microwave emissions of the vapor and liquid water molecules in the atmosphere at specific frequencies.

  4. Large Volume Coagulation Utilizing Multiple Cavitation Clouds Generated by Array Transducer Driven by 32 Channel Drive Circuits

    NASA Astrophysics Data System (ADS)

    Nakamura, Kotaro; Asai, Ayumu; Sasaki, Hiroshi; Yoshizawa, Shin; Umemura, Shin-ichiro

    2013-07-01

    High-intensity focused ultrasound (HIFU) treatment is a noninvasive treatment, in which focused ultrasound is generated outside the body and coagulates a diseased tissue. The advantage of this method is minimal physical and mental stress to the patient, and the disadvantage is the long treatment time caused by the smallness of the therapeutic volume by a single exposure. To improve the efficiency and shorten the treatment time, we are focusing attention on utilizing cavitation bubbles. The generated microbubbles can convert the acoustic energy into heat with a high efficiency. In this study, using the class D amplifiers, which we have developed, to drive the array transducer, we demonstrate a new method to coagulate a large volume by a single HIFU exposure through generating cavitation bubbles distributing in a large volume and vibrating all of them. As a result, the coagulated volume by the proposed method was 1.71 times as large as that of the conventional method.

  5. Microwave Processing of Crowns from Winter Cereals for Light Microscopy.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microwave processing of tissue considerably shortens the time it takes to prepare samples for light and electron microscopy. However, plant tissues from different species and different regions of the plant respond differently making it impossible to use a single protocol for all plant tissue. The ...

  6. Low frequency plasmonic state and negative permittivity spectra of coagulated Cu granular composite materials in the percolation threshold

    NASA Astrophysics Data System (ADS)

    Tsutaoka, Takanori; Kasagi, Teruhiro; Yamamoto, Shinichiro; Hatakeyama, Kenichi

    2013-05-01

    We have studied the relative complex permittivity (ɛr = ɛr'- iɛr″) of copper granular composite materials containing coagulated Cu particles in the microwave range as well as the electrical conductivity. The insulator to metal transition was observed at the percolation threshold φc = 16.0 vol. %. The enhancement of permittivity in the insulating state can be described by the Effective Cluster Model. Above the percolation threshold φc, it was found that the Cu granular composites show negative permittivity spectra below a characteristic frequency f0 indicating the low frequency plasmonic state. Characteristic frequency tends to increase with particle content.

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

    SciTech Connect

    Mankelevich, Yu. A.; Olevanov, M. A.; Pal, A. F.; Rakhimova, T. V.; Ryabinkin, A. N.; Serov, A. O.; Filippov, A. V.

    2008-09-07

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

  8. Cellular proteins of Microcystis aeruginosa inhibiting coagulation with polyaluminum chloride.

    PubMed

    Takaara, Tomoko; Sano, Daisuke; Konno, Hiroshi; Omura, Tatsuo

    2007-04-01

    Cyanobacterial growth in semi-closed water areas such as reservoirs brings about a coagulation inhibition in a drinking water treatment system, but the inhibitory substances and mechanisms involved have yet to be elucidated. In this study, proteins having a high affinity with polyaluminum chloride (PACl) were isolated from organic substances produced by Microcystis aeruginosa with the affinity chromatography technique. Both extracellular organic matter (EOM) and cellular organic matter (COM) disturbed the flocculation of suspended kaolin with PACl, but it was likely that nonproteinous substances in EOM cause the reduction of coagulation effciency. In contrast, proteins in COM were obtained as possible inhibitory substances for the coagulation with PACl. These proteins could consume PACl in the coagulation process due to the formation of chelate complexes between these inhibitory proteins and the coagulant. The consumption of PACl by cyanobacterial proteins could be one of the important causes of the increase in coagulant demand.

  9. Carbon nanotubes and microwaves: interactions, responses, and applications.

    PubMed

    Vázquez, Ester; Prato, Maurizio

    2009-12-22

    The interaction of microwaves with carbon nanotubes (CNTs) is an interesting topic for a variety of potential applications. Microwaves have been used for the purification of CNTs and for their chemical functionalization, providing a technique for simple, green, and large-scale protocols. In addition, the selective destruction of metallic CNTs under microwave irradiation could potentially result in a batch of semiconducting-only nanotubes. As an innovative application, the combination of microwaves with well-aligned CNTs could produce a new illumination technology. Moreover, the microwave absorbing properties of CNTs and their different behavior from typical organic compounds may open the door to the preparation of a wide range of new materials useful in many fields. A few examples of practical applications include electromagnetic interference for protecting the environment from radiation and microwave hyperthermia for cancer treatment as well as other medical therapies requiring precise heating of biological tissues.

  10. Coagulation Defects in Experimental Hepatic Injury in the Dog

    PubMed Central

    Osbaldiston, G. W.; Hoffman, Marcia W.

    1971-01-01

    Alteration in activity of blood coagulation factors in dogs with acute hepatic injury caused by oral carbon tetrachloride dosing was studied. Coagulation Factors II, VII and IX were dramatically reduced within 48 hours but recovered to normal in the next five days. Because surgery is rarely performed on dogs with hepatic necrosis, the use of fresh whole blood tranfusion to improve the coagulation defect in hepatic injury was also studied. Transfusion was found to have only a temporary beneficial effect. PMID:4253461

  11. Microwave sintering of ceramics

    SciTech Connect

    Snyder, W.B.

    1989-01-01

    Successful adaptation of microwave heating to the densification of ceramic materials require a marriage of microwave and materials technologies. Using an interdisciplinary team of microwave and materials engineers, we have successfully demonstrated the ability to density ceramic materials over a wide range of temperatures. Microstructural evolution during microwave sintering has been found to be significantly different from that observed in conventional sintering. Our results and those of others indicate that microwave sintering has the potential to fabricate components to near net shape with mechanical properties equivalent to hot pressed or hot isostatically pressed material. 6 refs., 11 figs.

  12. Predictive factors for beneficial application of high-frequency electromagnetics for tumour vaporization and coagulation in neurosurgery

    PubMed Central

    Ritz, Rainer; Heckl, Stefan; Safavi-Abbasi, Sam; Feigl, Guenther C; Krischek, Boris; Lüdemann, Wolf; Mirzayan, Javed M; Koerbel, Andrei; Samii, Madjid; Tatagiba, Marcos; Gharabaghi, Alireza

    2008-01-01

    Objective To identify preoperative and intraoperative factors and conditions that predicts the beneficial application of a high-frequency electromagnetic field (EMF) system for tumor vaporization and coagulation. Methods One hundred three subsequent patients with brain tumors were microsurgically treated using the EMF system in addition to the standard neurosurgical instrumentarium. A multivariate analysis was performed regarding the usefulness (ineffective/useful/very helpful/essential) of the new technology for tumor vaporization and coagulation, with respect to tumor histology and location, tissue consistency and texture, patients' age and sex. Results The EMF system could be used effectively during tumor surgery in 83 cases with an essential contribution to the overall success in 14 cases. In the advanced category of effectiveness (very helpful/essential), there was a significant difference between hard and soft tissue consistency (50 of 66 cases vs. 3 of 37 cases). The coagulation function worked well (very helpful/essential) for surface (73 of 103 cases) and spot (46 of 103 cases) coagulation when vessels with a diameter of less than one millimeter were involved. The light-weight bayonet hand piece and long malleable electrodes made the system especially suited for the resection of deep-seated lesions (34 of 52 cases) compared to superficial tumors (19 of 50 cases). The EMF system was less effective than traditional electrosurgical devices in reducing soft glial tumors. Standard methods where also required for coagulation of larger vessels. Conclusion It is possible to identify factors and conditions that predict a beneficial application of high-frequency electromagnetics for tumor vaporization and coagulation. This allows focusing the use of this technology on selective indications. PMID:18445296

  13. Effects of microwave radiation on the eye: The occupational health perspective

    SciTech Connect

    Cutz, A. )

    1989-01-01

    The purpose of this overview is to promote an interest in understanding and reducing the possible occupational health risks of microwave radiation on the eye. Microwaves act on living tissue through two types of mechanisms, thermal and nonthermal. Lens opacities can be induced in experimental animals at relatively high intensities (power densities greater than 100 mW/cm2). For lower intensities, lens changes may depend on the cumulative dose. At nonthermal intensities, microwaves can act as a trigger and set off changes in the living tissues (e.g. Ca++ efflux). Some cataract-causing agents (alloxan and galactose) act synergistically with microwaves. Microwaves also accelerate formation of cataracts due to diabetes. The corneal endothelium can be damaged by microwaves alone or in combination with some drugs. Microwave degeneration of retinal nerve endings and a small increase in retinal permeability were also found in animals. The effect of long-term low-intensity microwave exposure on the human lens remains poorly understood. Several reports have implicated occupational microwave exposure as a factor in increasing the rate of lens aging and retinal injury in microwave workers. In Canada, recommended microwave exposure limits are set at 25 mW/cm2 for microwave workers and at 1 mW/cm2 for the general public (both averaged over 1 minute). The Australian microwave exposure safety standard (1985) recommends pre- and post-employment eye examinations for workers.

  14. Recovery of struvite via coagulation and flocculation using natural compounds.

    PubMed

    Latifian, Maryam; Liu, Jing; Mattiasson, Bo

    2014-01-01

    One of the major setbacks of struvite recovery processes is the difficulty in harvesting struvite crystals. This study evaluates the use of different coagulants to improve precipitation of struvite (MgNH4PO4.6H20) crystals. Chitosan and poly(diallyldimethyl ammonium chloride) (Poly-DADMAC) as a coagulant-flocculent and alginate and bentonite as a coagulant aid have been examined in jar tests. Also, a continuous three-phase process, i.e., struvite crystallization, coagulation/flocculation and precipitation process, was set up for real wastewater. Addition of chitosan as the coagulant and bentonite as the coagulant aid was significantly more efficient in forming struvite flocs in comparison to Poly-DADMAC alone or with coagulant aid, which did not show any positive effect. The calculated average settling velocity of struvite with chitosan-bentonite addition in synthetic and in real wastewater increased by approximately 5.3 and 2.8 folds, respectively, compared with that of no coagulant/flocculent addition. Phosphorus recovery of over 70% was achieved by the continuous process. Findings in this study clearly confirmed the possibility of using chitosan and bentonite as an efficient coagulant-flocculent to enhance the recovery of struvite crystals.

  15. Improving the efficiency of clarifiers for coagulation treatment of water

    NASA Astrophysics Data System (ADS)

    Vinogradov, V. N.; Smirnov, B. A.; Zhadan, A. V.; Avan, V. K.

    2010-08-01

    Technological and design possibilities of improving clarifiers for coagulation treatment of water are considered. The results obtained from implementing these possibilities in real devices are presented.

  16. Innate immunity, coagulation and placenta-related adverse pregnancy outcomes.

    PubMed

    Li, Min; Huang, S Joseph

    2009-12-01

    Maternal immunity undergoes subtle adjustment in order to tolerate the semi-allogeneic embryo and maintain the host defense against potential pathogens. Concomitantly, coagulation systems change from an anti-coagulant state to a pro-coagulant state to meet the hemostatic challenge of placentation and delivery. Innate immunity and blood coagulation systems are the first line of defense to protect a host against exogenous challenges, including alloantigens and mechanical insults, and preserve the integrity of an organism. The interactions between coagulation and immune systems have been extensively studied. Immune cells play a pivotal role in the initiation of the coagulation cascade, whereas coagulation proteases display substantial immuno-modulatory effects. Upon exogenous challenges, the immune and coagulation systems are capable of potentiating each other leading to a vicious cycle. Natural killer (NK) cells, macrophages (Mphis) and dendritic cells (DCs) are three major innate immune cells that have been demonstrated to play essential roles in early pregnancy. However, immune maladaptation and hemostatic imbalance have been suggested to be responsible for adverse pregnant outcomes, such as preeclampsia (PE), miscarriage, recurrent spontaneous abortion (RSA) and intrauterine growth restriction (IUGR). In this review, we will summarize the mutual regulation between blood coagulation and innate immune systems as well as their roles in the maintenance of normal pregnancy and in the pathogenesis of adverse pregnancy outcomes.

  17. High brightness microwave lamp

    DOEpatents

    Kirkpatrick, Douglas A.; Dolan, James T.; MacLennan, Donald A.; Turner, Brian P.; Simpson, James E.

    2003-09-09

    An electrodeless microwave discharge lamp includes a source of microwave energy, a microwave cavity, a structure configured to transmit the microwave energy from the source to the microwave cavity, a bulb disposed within the microwave cavity, the bulb including a discharge forming fill which emits light when excited by the microwave energy, and a reflector disposed within the microwave cavity, wherein the reflector defines a reflective cavity which encompasses the bulb within its volume and has an inside surface area which is sufficiently less than an inside surface area of the microwave cavity. A portion of the reflector may define a light emitting aperture which extends from a position closely spaced to the bulb to a light transmissive end of the microwave cavity. Preferably, at least a portion of the reflector is spaced from a wall of the microwave cavity. The lamp may be substantially sealed from environmental contamination. The cavity may include a dielectric material is a sufficient amount to require a reduction in the size of the cavity to support the desired resonant mode.

  18. Physical Basis And Technology Of Microwave Radiometry

    NASA Astrophysics Data System (ADS)

    Mamouni, A.; N'Guven, D. D.; Robillard, M.; Chive, M.; Leroy, Y.

    1980-05-01

    Thermal noise detection in microwave frequency range can lead to a non invasive subcutaneous temperature measurement in the living tissues. Several clinical aoplications are mentioned (cancer detection, brain temperature measurements, ergonomics). First experiments, and computations on thermal models show a possible achievement of a new method concerning a thermal pattern recognition.

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

    PubMed

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

    2014-11-01

    The objective of this study was to investigate the influence of coagulant dosage and pH on coagulation performance and floc properties using polyaluminum chloride (PAC) and compound bioflocculant (CBF) dual-coagulant in kaolin-humic acid (HA) treatment. Results showed that as PAC dosage rose, comparatively better coagulation efficiencies and floc characteristics were achieved due to stronger charge neutralization and sweeping effect. Addition of CBF could enhance coagulation performance and floc properties, including size, strength and recoverability, except fractal dimension. Solution pH had a significant effect on coagulation efficiencies and flocs formation. Under acidic condition, flocs showed higher strength and recoverability but lower fractal dimension, where charge neutralization was the foremost mechanism. More compact flocs were generated under alkaline condition due to the sweeping effect of hydrolyzed Al species.

  20. Microwave hemorrhagic stroke detector

    DOEpatents

    Haddad, Waleed S.; Trebes, James E.

    2002-01-01

    The microwave hemorrhagic stroke detector includes a low power pulsed microwave transmitter with a broad-band antenna for producing a directional beam of microwaves, an index of refraction matching cap placed over the patients head, and an array of broad-band microwave receivers with collection antennae. The system of microwave transmitter and receivers are scanned around, and can also be positioned up and down the axis of the patients head. The microwave hemorrhagic stroke detector is a completely non-invasive device designed to detect and localize blood pooling and clots or to measure blood flow within the head or body. The device is based on low power pulsed microwave technology combined with specialized antennas and tomographic methods. The system can be used for rapid, non-invasive detection of blood pooling such as occurs with hemorrhagic stroke in human or animal patients as well as for the detection of hemorrhage within a patient's body.

  1. Microwave hemorrhagic stroke detector

    DOEpatents

    Haddad, Waleed S.; Trebes, James E.

    2007-06-05

    The microwave hemorrhagic stroke detector includes a low power pulsed microwave transmitter with a broad-band antenna for producing a directional beam of microwaves, an index of refraction matching cap placed over the patients head, and an array of broad-band microwave receivers with collection antennae. The system of microwave transmitter and receivers are scanned around, and can also be positioned up and down the axis of the patients head. The microwave hemorrhagic stroke detector is a completely non-invasive device designed to detect and localize blood pooling and clots or to measure blood flow within the head or body. The device is based on low power pulsed microwave technology combined with specialized antennas and tomographic methods. The system can be used for rapid, non-invasive detection of blood pooling such as occurs with hemorrhagic stoke in human or animal patients as well as for the detection of hemorrhage within a patient's body.

  2. Activation of coagulation in bullous pemphigoid and other eosinophil-related inflammatory skin diseases

    PubMed Central

    Marzano, A V; Tedeschi, A; Berti, E; Fanoni, D; Crosti, C; Cugno, M

    2011-01-01

    Bullous pemphigoid (BP) is a skin disease caused by autoantibodies to hemidesmosomal proteins BP180 and BP230, with eosinophils participating in blister formation. Tissue factor (TF), the initiator of coagulation, is embodied within the eosinophil granules and exposed upon activation. We evaluated the coagulation activation in patients with BP (63), chronic urticaria (CU; 20), atopic dermatitis (AD; 14), cutaneous drug reactions (CDRs; six), psoriasis (20), dermatitis herpetiformis (DH; four) and primary cutaneous T cell lymphoma (CTCL; five), and in 40 healthy controls. Prothrombin fragment F1+2 and d-dimer (coagulation markers) were measured by enzyme-linked immunosorbent assay (ELISA) in all plasma samples and BP blister fluid. Skin TF expression was evaluated immunohistochemically in the patients and 20 controls. F1+2 and d-dimer levels were higher in BP plasma than in control plasma (P = 0·0001 for both), and dramatically high in blister fluid; both correlated positively with disease severity, esinophil counts and anti-BP180 antibodies (P = 0·006–0·0001). Plasma F1+2 and d-dimer levels were higher in the CU, AD and CDR patients than in controls (P = 0·0001 for all), but normal in the psoriasis, DH and CTCL patients. Skin TF was expressed in the BP (P = 0·0001), CU (P = 0·0001), AD (P = 0·001) and CDR patients (P = 0·01), but not in the psoriasis, DH or CTCL patients. Co-localization confocal microscopy studies confirmed eosinophils as the source of TF in 10 BP patients. The coagulation cascade is activated in BP and other eosinophil-mediated skin disorders, but not in non-eosinophil driven conditions. This hypercoagulability may contribute to inflammation, tissue damage and, possibly, thrombotic risk. PMID:21488867

  3. Activation of Blood Coagulation in Two Prototypic Autoimmune Skin Diseases: A Possible Link with Thrombotic Risk.

    PubMed

    Cugno, Massimo; Tedeschi, Alberto; Borghi, Alessandro; Bucciarelli, Paolo; Asero, Riccardo; Venegoni, Luigia; Griffini, Samantha; Grovetti, Elena; Berti, Emilio; Marzano, Angelo Valerio

    2015-01-01

    Coagulation activation has been demonstrated in two prototypic autoimmune skin diseases, chronic autoimmune urticaria and bullous pemphigoid, but only the latter is associated with increased thrombotic risk. Two markers of coagulation activation (prothrombin fragment F1+2 and fibrin fragment D-dimer) were measured by immunoenzymatic methods in plasma samples from 30 patients with active chronic autoimmune urticaria, positive for autologous serum skin test, 30 patients with active bullous pemphigoid and 30 healthy subjects. In skin biopsies, tissue factor expression was evaluated by both immunohistochemistry and in situ hybridization. F1+2 and D-dimer levels were higher in active chronic autoimmune urticaria (276.5±89.8 pmol/L and 5.56±4.40 nmol/L, respectively) than in controls (145.2±38.0 pmol/L and 1.06±0.25 nmol/L; P=0.029 and P=0.011) and were much higher in active bullous pemphigoid (691.7±318.7 pmol/L and 15.24±9.09 nmol/L, respectively) (P<0.0001). Tissue factor positivity was evident in skin biopsies of both disorders with higher intensity in bullous pemphigoid. F1+2 and D-dimer, during remission, were markedly reduced in both disorders. These findings support the involvement of coagulation activation in the pathophysiology of both diseases. The strong systemic activation of coagulation in bullous pemphigoid may contribute to increase the thrombotic risk and provides the rationale for clinical trials on anticoagulant treatments in this disease.

  4. Contact activation of blood-plasma coagulation.

    PubMed

    Vogler, Erwin A; Siedlecki, Christopher A

    2009-04-01

    This opinion identifies inconsistencies in the generally-accepted surface biophysics involved in contact activation of blood-plasma coagulation, reviews recent experimental work aimed at resolving inconsistencies, and concludes that this standard paradigm requires substantial revision to accommodate new experimental observations. Foremost among these new findings is that surface-catalyzed conversion of the blood zymogen factor XII (FXII, Hageman factor) to the enzyme FXIIa (FXII [surface] --> FXIIa, a.k.a. autoactivation) is not specific for anionic surfaces, as proposed by the standard paradigm. Furthermore, it is found that surface activation is moderated by the protein composition of the fluid phase in which FXII autoactivation occurs by what appears to be a protein-adsorption-competition effect. Both of these findings argue against the standard view that contact activation of plasma coagulation is potentiated by the assembly of activation-complex proteins (FXII, FXI, prekallikrein, and high-molecular weight kininogen) directly onto activating surfaces (procoagulants) through specific protein/surface interactions. These new findings supplement the observation that adsorption behavior of FXII and FXIIa is not remarkably different from a wide variety of other blood proteins surveyed. Similarity in adsorption properties further undermines the idea that FXII and/or FXIIa are distinguished from other blood proteins by unusual adsorption properties resulting in chemically-specific interactions with activating anionic surfaces. IMPACT STATEMENT: This review shows that the consensus biochemical mechanism of contact activation of blood-plasma coagulation that has long served as a rationale for poor hemocompatibility is an inadequate basis for surface engineering of advanced cardiovascular biomaterials.

  5. [Clinical cases of acquired coagulation inhibitors].

    PubMed

    Yamane, T; Hino, M; Ota, K; Akahori, M; Hirai, M; Inoue, T; Mugitani, A; Tatsumi, N

    2000-12-01

    The acquired coagulation factor inhibitors are classified into alloantibodies, which appear in association with supplementary treatment for congenital coagulation factor deficiency, and autoantibodies, which are spontaneously produced. We report here 2 cases of acquired factor VIII inhibitor and 1 case of factor V inhibitor. Case 1: A 52-year-old woman noted swelling of the right parotid region in March 1988. Though contrast examination was scheduled, she was admitted for detailed examination due to a markedly prolonged coagulation time. An APTT correction test suggested that decreased factor VIII activity was due to the presence of an inhibitor. Since antinuclear antibody and SS-A antibody were positive and infiltration by lymphocytes in the salivary gland acini in a lip biopsy specimen was detected, Sjögren's syndrome was diagnosed. Case 2: A 33-year-old woman had normal delivery of her second child in February 1998. In June 1998, she suffered slight contusion in the left lower limb. The affected site became swollen and painful, making walking difficult. Since both upper limbs became markedly swollen after 1 week, she visited our hospital. Prolonged APTT and a marked decrease in factor VIII activity were observed. Factor VIII inhibitor titer was high at 19 Bethesda units. Case 3: A 64-year-old man had had asymptomatic macroscopic hematuria since the beginning of August 1998 but was placed under observation since no abnormal findings were observed on various imaging tests. However, he was admitted to Osaka City General Medical Center because of vesicular tamponade. Factor V activity was markedly decreased to 1.0%. PT correction test suggested that decreased factor V activity was due to the presence of an inhibitor. The underlying disease could not be determined in this case. In patients with acquired coagulation inhibitors, bleeding symptoms are reported to be mild in many cases, and severe bleeding is rare. However, cases of death without severe bleeding or

  6. A new approach using coagulation rate constant for evaluation of turbidity removal

    NASA Astrophysics Data System (ADS)

    Al-Sameraiy, Mukheled

    2015-09-01

    Coagulation-flocculation-sedimentation processes for treating three levels of bentonite synthetic turbid water using date seeds (DS) and alum (A) coagulants were investigated in the previous research work. In the current research, the same experimental results were used to adopt a new approach on a basis of using coagulation rate constant as an investigating parameter to identify optimum doses of these coagulants. Moreover, the performance of these coagulants to meet (WHO) turbidity standard was assessed by introducing a new evaluating criterion in terms of critical coagulation rate constant (kc). Coagulation rate constants (k2) were mathematically calculated in second order form of coagulation process for each coagulant. The maximum (k2) values corresponded to doses, which were obviously to be considered as optimum doses. The proposed criterion to assess the performance of coagulation process of these coagulants was based on the mathematical representation of (WHO) turbidity guidelines in second order form of coagulation process stated that (k2) for each coagulant should be ≥ (kc) for each level of synthetic turbid water. For all tested turbid water, DS coagulant could not satisfy it. While, A coagulant could satisfy it. The results obtained in the present research are exactly in agreement with the previous published results in terms of finding optimum doses for each coagulant and assessing their performances. On the whole, it is recommended considering coagulation rate constant to be a new approach as an indicator for investigating optimum doses and critical coagulation rate constant to be a new evaluating criterion to assess coagulants' performance.

  7. Coagulant recovery and reuse for drinking water treatment.

    PubMed

    Keeley, James; Jarvis, Peter; Smith, Andrea D; Judd, Simon J

    2016-01-01

    Coagulant recovery and reuse from waterworks sludge has the potential to significantly reduce waste disposal and chemicals usage for water treatment. Drinking water regulations demand purification of recovered coagulant before they can be safely reused, due to the risk of disinfection by-product precursors being recovered from waterworks sludge alongside coagulant metals. While several full-scale separation technologies have proven effective for coagulant purification, none have matched virgin coagulant treatment performance. This study examines the individual and successive separation performance of several novel and existing ferric coagulant recovery purification technologies to attain virgin coagulant purity levels. The new suggested approach of alkali extraction of dissolved organic compounds (DOC) from waterworks sludge prior to acidic solubilisation of ferric coagulants provided the same 14:1 selectivity ratio (874 mg/L Fe vs. 61 mg/L DOC) to the more established size separation using ultrafiltration (1285 mg/L Fe vs. 91 mg/L DOC). Cation exchange Donnan membranes were also examined: while highly selective (2555 mg/L Fe vs. 29 mg/L DOC, 88:1 selectivity), the low pH of the recovered ferric solution impaired subsequent treatment performance. The application of powdered activated carbon (PAC) to ultrafiltration or alkali pre-treated sludge, dosed at 80 mg/mg DOC, reduced recovered ferric DOC contamination to <1 mg/L but in practice, this option would incur significant costs. The treatment performance of the purified recovered coagulants was compared to that of virgin reagent with reference to key water quality parameters. Several PAC-polished recovered coagulants provided the same or improved DOC and turbidity removal as virgin coagulant, as well as demonstrating the potential to reduce disinfection byproducts and regulated metals to levels comparable to that attained from virgin material.

  8. Cosmic dust synthesis by accretion and coagulation

    NASA Technical Reports Server (NTRS)

    Praburam, G.; Goree, J.

    1995-01-01

    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.

  9. Inherited coagulation disorders in southern Iran.

    PubMed

    Karimi, M; Yarmohammadi, Hirad; Ardeshiri, R; Yarmohammadi, Hooman

    2002-11-01

    A comprehensive survey concerning the Shiraz Hemophilia Society and the associated haemophilia treatment centre was undertaken in April 2002 to collect data on demographics, signs and symptoms in the southern Iranian population with haemophilia and allied disorders. The total number of patients with coagulation disorders was 367. Haemophilia A (factor [F] VIII deficiency) was found in 271, 39 had haemophilia B (FIX deficiency) and 24 had von Willebrand disease. The rare coagulation disorders (n = 33) included 11 patients with FX deficiency; 10 with FVII; six with FXIII; two with afibrinogenaemia; two with FXI; one with combined FVIII and FV; and one with combined FVII, FVIII and FIX deficiency. The prevalence was 6.64 per 100,000 inhabitants. The most common symptoms were haemarthrosis, haematomas and epistaxis. None of the patients were human immunodeficiency virus positive but 47 (15%) were hepatitis C virus positive and two (0.7%) were hepatitis B positive, so that the rate of transfusion-transmitted infections was lower compared with other populations.

  10. Optical and thermal simulations of noninvasive laser coagulation of the human vas deferens

    NASA Astrophysics Data System (ADS)

    Schweinsberger, Gino R.; Cilip, Christopher M.; Trammell, Susan R.; Cherukuri, Harish; Fried, Nathaniel M.

    2011-03-01

    Successful noninvasive laser coagulation of the canine vas deferens, in vivo, has been previously reported. However, there is a significant difference between the optical properties of canine and human skin. In this study, Monte Carlo simulations of light transport through tissue and heat transfer simulations are performed to determine the feasibility of noninvasive laser vasectomy in humans. A laser wavelength of 1064 nm was chosen for deep optical penetration in tissue. Monte Carlo simulations determined the spatial distribution of absorbed photons inside the tissue layers (epidermis, dermis, and vas). The results were convolved with a 3-mm-diameter laser beam, and then used as the spatial heat source for the heat transfer model. A laser pulse duration of 500 ms and pulse rate of 1 Hz, and cryogen spray cooling were incident on the tissue for 60 s. Average laser power (5-9 W), cryogen pulse duration (60-100 ms), cryogen cooling rate (0.5-1.0 Hz), and increase in optical transmission due to optical clearing (0-50 %), were studied. After application of an optical clearing agent to increase skin transmission by 50%, an average laser power of 6 W, cryogen pulse duration of 60 ms, and cryogen cooling rate of 1 Hz resulted in vas temperatures of ~ 60°C, sufficient for thermal coagulation, while 1 mm of the skin surface (epidermis and dermis) remained at a safe temperature of ~ 45 °C. Monte Carlo and heat transfer simulations indicate that it is possible to noninvasively thermally coagulate the human vas without adverse effects (e.g. scrotal skin burns), if an optical clearing agent is applied to the skin prior to the procedure.

  11. Analysis and optimization of coagulation and flocculation process

    NASA Astrophysics Data System (ADS)

    Saritha, V.; Srinivas, N.; Srikanth Vuppala, N. V.

    2015-02-01

    Natural coagulants have been the focus of research of many investigators through the last decade owing to the problems caused by the chemical coagulants. Optimization of process parameters is vital for the effectiveness of coagulation process. In the present study optimization of parameters like pH, dose of coagulant and mixing speed were studied using natural coagulants sago and chitin in comparison with alum. Jar test apparatus was used to perform the coagulation. The results showed that the removal of turbidity was up to 99 % by both alum and chitin at lower doses of coagulant, i.e., 0.1-0.3 g/L, whereas sago has shown a reduction of 70-100 % at doses of 0.1 and 0.2 g/L. The optimum conditions observed for sago were 6 and 7 whereas chitin was stable at all pH ranges, lower coagulant doses, i.e., 0.1-0.3 g/L and mixing speed—rapid mixing at 100 rpm for 10 min and slow mixing 20 rpm for 20 min. Hence, it can be concluded that sago and chitin can be used for treating water even with large seasonal variation in turbidity.

  12. Metals in airpollution particles decrease whole blood coagulation time

    EPA Science Inventory

    The mechanism underlying the pro-coagulative effect of air pollution particle exposure is not known. We tested the postulate that 1) the soluble fraction ofan air pollution particle can affect whole blood coagulation time and 2) metals included in the soluble fraction are respons...

  13. Characteristics of particle coagulation in an underground parking lot.

    PubMed

    Zhao, Yu; Kato, Shinsuke; Zhao, Jianing

    2015-12-01

    Particles in vehicle exhaust plumes in underground parking lots have adverse health effects due to the enclosed environment in which they are released and the temperature difference between the tailpipe and ambient environment; at the same time, particle coagulation might be obvious near the tailpipe in an underground parking lot. In the present study, airflow and temperature fields were calculated using the Realizable k-ε model, and the Eulerian particle transport model was selected in the numerical simulation of particle concentration dispersion. Polydisperse thermal coagulation due to Brownian collisions was employed to calculate the particle coagulation. The results show that particle coagulation rate and half-time were significant within 1 m from the tailpipe. The variations in the particle coagulation rate and half-time were similar, but their directions were opposite. Air exhaust time was nearly four times longer than averaged half-time and 40 times longer than minimum half-time. The peak particle diameter increased approximately 1.43 times due to coagulation. A double particle concentration at the tailpipe caused the fourfold rise in the particle coagulation rate in the distance ranging less than 1 m from the tailpipe. An increase in exhaust velocity at the tailpipe could shorten the obvious range of particle coagulation along the centerline of the tailpipe from 1 to 0.8 m in the study.

  14. Coagulation chemistries for silica removal from cooling tower water.

    SciTech Connect

    Nyman, May Devan; Altman, Susan Jeanne; Stewart, Tom

    2010-02-01

    The formation of silica scale is a problem for thermoelectric power generating facilities, and this study investigated the potential for removal of silica by means of chemical coagulation from source water before it is subjected to mineral concentration in cooling towers. In Phase I, a screening of many typical as well as novel coagulants was carried out using concentrated cooling tower water, with and without flocculation aids, at concentrations typical for water purification with limited results. In Phase II, it was decided that treatment of source or make up water was more appropriate, and that higher dosing with coagulants delivered promising results. In fact, the less exotic coagulants proved to be more efficacious for reasons not yet fully determined. Some analysis was made of the molecular nature of the precipitated floc, which may aid in process improvements. In Phase III, more detailed study of process conditions for aluminum chloride coagulation was undertaken. Lime-soda water softening and the precipitation of magnesium hydroxide were shown to be too limited in terms of effectiveness, speed, and energy consumption to be considered further for the present application. In Phase IV, sodium aluminate emerged as an effective coagulant for silica, and the most attractive of those tested to date because of its availability, ease of use, and low requirement for additional chemicals. Some process optimization was performed for coagulant concentration and operational pH. It is concluded that silica coagulation with simple aluminum-based agents is effective, simple, and compatible with other industrial processes.

  15. Disseminated intravascular coagulation and acute myocardial necrosis caused by lightning.

    PubMed

    Ekoé, J M; Cunningham, M; Jaques, O; Balague, F; Baumann, R P; Humair, L; de Torrenté, A

    1985-01-01

    A 24-year-old woman was struck by lightning and suffered 20% second degree burns. She was admitted after cardiac and respiratory arrest. Despite intensive supportive care she died 24 h later of cardiogenic shock complicated by disseminated intravascular coagulation. At autopsy there was myocardial necrosis. Disseminated intravascular coagulation and myocardial necrosis are only rarely described as complications of lightning.

  16. Use of microwave in diagnostic pathology.

    PubMed

    Shruthi, Basavaradhya Sahukar; Vinodhkumar, Palani; Kashyap, Bina; Reddy, Padala Sridhar

    2013-01-01

    Conventional tissue fixation and processing is as old as 100 years and still remains the gold standard against which all new technologies and methods need to be assessed. Tissue processing is one of the important steps for obtaining good thin sections without artifacts. Though conventional tissue-processing methods are most commonly followed, they are well-known as very laborious and tedious procedures. Microwaves a form of electromagnetic wave-induced heat, when applied in histotechnology, reproducibly yields histolologic material of similar or superior quality to that provided by conventional processing methods, making it more popular in the recent years. A laboratory microwave offers features like maximum output of 2000-3000 watts, an in-built source of adjustable temperature probe, facility for ventilation of hazardous fumes, but is expensive. Considering the usefulness of microwave in histotechnology, i.e., reducing the time required for the diagnosis, replacing the conventional equipments of laboratories by microwave-guided ones is a remarkable and an acceptable change.

  17. Performance and characterization of a new tannin-based coagulant

    NASA Astrophysics Data System (ADS)

    Beltrán-Heredia, J.; Sánchez-Martín, J.; Gómez-Muñoz, C.

    2012-09-01

    Diethanolamine and formaldehyde were employed to cationize tannins from black wattle. This novel coagulant called CDF was functionally characterized in removing sodium dodecylbenzene sulfonate (anionic surfactant) and Palatine Fast Black WAN (azoic dye). Refined tannin-derived commercial coagulants exhibited similar efficiency, while CDF presented higher coagulant ability than alum, a usual coagulant agent. Low doses of CDF (ca. 100 mg L-1) were able to remove more than 70 % of surfactant and more than 85 % of dye (initial pollutant concentration of ca. 100 mg L-1) and it presented no temperature affection and worked at a relatively wide pH range. Surfactant and dye removal responded to the classical coagulant-and-adsorption models, such as Frumkin-Fowler-Guggenheim or Gu and Zhu in the case of surfactant, and Langmuir and Freundlich in the case of dye.

  18. Analysis of Coagulation Processes for the Groundwater Treatment

    NASA Astrophysics Data System (ADS)

    Albrektiene, Ramune; Rimeika, Mindaugas; Jurkiene, Anzelika

    2013-06-01

    Coagulation process is widely used for removal of natural organic matters (NOM) and for water color intensity reduction. The efficiency of coagulation process depends on many different factors. Aim of this research is to investigate coagulation process under different conditions. During the research coagulation process was held at different pH values (5.5; 6.0; 6.5), at different water alkalinity and at different water turbidity. It was found that removal of NOM and water color intensity reduction is most effective at pH values from 5.5 to 6.0. At these conditions water color intensity reduction is most efficient, but removal of dissolved organic carbon (DOC) is the lowest. During the research it was also found that different water alkalinity and turbidity do not make significant influence on efficiency of coagulation process.

  19. Microwave Processing of Materials

    DTIC Science & Technology

    1994-01-01

    of peak output power of 100 megawatts at 10 GHz. Microwave Fundamentals 11 RESONANT HELIX TWT STO KLYSTRON CTf C 0 Grid oShadow Grid PPM FOCUS SPACE C...Rather, broadband and high-temperature measurement techniques that have been used in conjunction with microwave processing of materials-specifically... Broadband Dielectric Properties Measurement Techniques. Pp. 527-539 in Materials Research Society Symposium Proceedings, Vol. 269, Microwave Processing

  20. Microwave Lightcraft concept

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Looking like an alien space ship or a flying saucer the Microwave Lightcraft is an unconventional launch vehicle approach for delivering payload to orbit using power transmitted via microwaves. Microwaves re beamed from either a ground station or an orbiting solar power satellite to the lightcraft. The energy received breaks air molecules into a plasma and a magnetohydrodynamic fanjet provides the lifting force. Only a small amount of propellant is required for circulation, attitude control and deorbit.

  1. Coagulation disorders and inhibitors of coagulation in children from Mansoura, Egypt.

    PubMed

    Abdelrazik, Nabil; Rashad, Hayam; Selim, Tarek; Tharwat, Layla

    2007-08-01

    Disorders of coagulation in children often prove challenging to the medical care team. The aims of this study were to assess the spectrum and prevalence of coagulation disorders among children attending Mansoura University Children Hospital (MUCH), Mansoura, Egypt. A total of 105 pediatric patients were referred to MUCH. They were divided into two groups: congenital coagulation disorders (75 cases, age 45.36 +/- 48.59 months), and acquired coagulation disorders (30 cases, age 56.13 +/- 61.61 months). All patients were subjected to thorough history taking including the nature of bleeding, family, past history, mode of inheritance, and detailed physical findings. Hemostatic tests included: platelet count, bleeding time (BT), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT). Specific tests in the congenital group include assay of coagulation factors according to each disorder, Von Willebrand factor assay, ristocetin aggregation test, APTT mixing study for detection of inhibitors in complicated hemophilia cases, F VIII C to VWAg ratio with cut off 0.7 for detection of carriers in some hemophilia A families. Congenital disorders constituted 71.4% of the studied cases vs. 28.6% for acquired disorders. Hemophilia A (42.85%), hemophilia B (14.28%) and liver diseases (14.28%) represented the majority of the studied cases. Mild and moderate cases of hemophilia A and B are more frequent than severe cases in both types. Male sex is more frequent than female in the congenital group (94.7 vs. 5.3%, P < 0.001). Direct correlation existed between factor level assay and severity of hemophilia (r = 0.73, P = 0.006). Three mothers and one sister were identified as carrier out of four families. Anti-clotting factors inhibitor was detected in 18.2% of patients with hemophilia A and in 9.1% with hemophilia B. In conclusion, our study found that hemophilias are the most prevalent congenital coagulation disorders among children. Attention must be

  2. The Role for Coagulation Markers in Mild Snakebite Envenomations

    PubMed Central

    Moriarity, Risa S; Dryer, Sylvia; Replogle, William; Summers, Richard L

    2012-01-01

    Introduction The majority of patients seeking medical treatment for snakebites do not suffer from severe envenomation. However, no guidelines exist for ordering coagulation markers in patients with minimal or moderate envenomation, nor in those who do not receive antivenom. In this study, we sought to determine whether it was possible to limit the practice of ordering coagulation studies to those patients suffering severe envenomation, rattlesnake envenomation, or both. Methods A retrospective chart review was performed on all cases of crotalid snakebite presenting to an adult emergency department (ED) from April 1998 to June 2006. Each chart was abstracted for patient's age, gender, type of snake (if known), severity of envenomation at initial presentation, coagulation test results, whether antivenom was administered, and whether the patient was admitted. Results Over an approximately 8-year period, 131 snakebite cases presented that met the inclusion criteria, of which 35 (26.7%) had some type of coagulation marker abnormality. Limiting coagulation testing to patients suffering severe envenomation or rattlesnake envenomation would have resulted in failure to identify 89% or 77%, respectively, of the 35 patients who were found to have at least 1 abnormal coagulation marker. Conclusion Our study failed to identify a subset of patients that could be defined as low risk or for whom coagulation marker testing could be foregone. This study suggests that coagulation tests should be routinely performed on all patients presenting to the ED with complaints of envenomation by copperheads, moccasins, or rattlesnakes. Further clarification of when coagulation markers are indicated may require a prospective study that standardizes snake identification and the timing of coagulation marker testing. PMID:22461925

  3. Advanced microwave processing concepts

    SciTech Connect

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.

    1995-05-01

    The purpose of this work is to explore the feasibility of several advanced microwave processing concepts to develop new energy-efficient materials and processes. The project includes two tasks: (1) commercialization of the variable-frequency microwave furnace; and (2) microwave curing of polymer composites. The variable frequency microwave furnace, whose initial conception and design was funded by the AIC Materials Program, will allow us, for the first time, to conduct microwave processing studies over a wide frequency range. This novel design uses a high-power traveling wave tube (TWT) originally developed for electronic warfare. By using this microwave source, one can not only select individual microwave frequencies for particular experiments, but also achieve uniform power densities over a large area by the superposition of many different frequencies. Microwave curing of thermoset resins will be studied because it hold the potential of in-situ curing of continuous-fiber composites for strong, lightweight components. Microwave heating can shorten curing times, provided issues of scaleup, uniformity, and thermal management can be adequately addressed.

  4. Advanced microwave processing concepts

    SciTech Connect

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.

    1997-04-01

    The purpose of this work is to explore the feasibility of several advanced microwave processing concepts to develop new energy-efficient materials and processes. The project includes two tasks: (1) commercialization of the variable-frequency microwave furnace; and (2) microwave curing of polymeric materials. The variable frequency microwave furnace, whose initial conception and design was funded by the AIM Materials Program, allows the authors, for the first time, to conduct microwave processing studies over a wide frequency range. This novel design uses a high-power traveling wave tube (TWT) originally developed for electronic warfare. By using this microwave source, one can not only select individual microwave frequencies for particular experiments, but also achieve uniform power densities over a large area by the superposition of many different frequencies. Microwave curing of various thermoset resins will be studied because it holds the potential of in-situ curing of continuous-fiber composites for strong, lightweight components or in-situ curing of adhesives, including metal-to-metal. Microwave heating can shorten curing times, provided issues of scaleup, uniformity, and thermal management can be adequately addressed.

  5. Digital communications: Microwave applications

    NASA Astrophysics Data System (ADS)

    Feher, K.

    Transmission concepts and techniques of digital systems are presented; and practical state-of-the-art implementation of digital communications systems by line-of-sight microwaves is described. Particular consideration is given to statistical methods in digital transmission systems analysis, digital modulation methods, microwave amplifiers, system gain, m-ary and QAM microwave systems, correlative techniques and applications to digital radio systems, hybrid systems, digital microwave systems design, diversity and protection switching techniques, measurement techniques, and research and development trends and unsolved problems.

  6. A hitherto undescribed plasma factor acting at the contact phase of blood coagulation (Flaujeac factor): case report and coagulation studies.

    PubMed

    Lacombe, M J; Varet, B; Levy, J P

    1975-11-01

    This paper reports an asymptomatic coagulation defect responsible for an abnormality at the contact phase of blood coagulation in vitro, distinct from Hageman factor and Fletcher factor deficiencies. Coagulation studies in a 50-yr-old French woman without bleeding tendency revealed the following results: whole-blood clotting time in glass tubes and activated partial thromboplastin time with kaolin and ellagic acid were greatly prolonged; one-stage prothrombin was normal; no circulating anticoagulant was detected, and the infusion of normal plasma corrected the coagulation defect with an estimated half-life of 6.5 days; the levels of factor VIII, IX, XI, and XII were normal; mutual correction was obtained with a Fletcher factor-deficient plasma; the level of whole complement was normal. Studies of the contact phase of blood coagulation and contact-induced fibrinolysis showed the same abnormalities as in Hageman factor- and Fletcher-deficient plasmas. These results indicate that the patient's plasma is deficient in a previously undescribed coagulation factor, which participates in the initial stage of the blood coagulation process in vitro. Family studies revealed consanguinity in the propositus' parents. The assay of this newly described factor in the propositus' children revealed a partial defect, compatible with a heterozygous state, in three of the four tested children. This indicates a recessive inheritance of this new blood coagulation defect.

  7. Development of coagulation regulatory proteins in the fetal and neonatal lamb.

    PubMed

    Manco-Johnson, Marilyn J; Jacobson, Linda J; Hacker, Michele R; Townsend, Susan F; Murphy, James; Hay, William

    2002-10-01

    To investigate the development of coagulation regulatory proteins-protein C (PC), protein S (PS), and antithrombin (AT)-in relationship to the procoagulant protein factor X (FX), a chronically catheterized fetal ovine model was used. Infusion and sampling catheters were placed into pregnant ewes and their fetuses and maintained from mid-gestation. From a total of 110 fetuses, 17 lambs, and 63 ewes that were studied on one to 15 occasions, 212 fetal, 88 neonatal, and 157 maternal samples were obtained. Liver tissue was obtained from 31 fetuses and 15 ewes. Plasma levels of all proteins studied were higher in the ewe than in the fetus (p < 0.0001). Plasma levels of FX, PC, and PS achieved neonatal levels by mid-gestation with mild but significant decreases during mid- and late gestation. Fetal and early neonatal plasma concentrations of these vitamin K-dependent proteins fit a model with both quadratic (p < 0.01) and linear (p < 0.01) components. The discrepant levels in mRNA relative to plasma concentration were consistent with regulatory control beyond the level of transcription. In contrast, a simple linear increase in plasma protein levels was determined for the vitamin K-independent coagulation regulatory protein, AT (p for quadratic component > 0.05). This study suggests that fetal regulation of coagulation proteins follows characteristic patterns relative to the vitamin K dependence of the protein rather than its role as a procoagulant versus regulatory protein.

  8. Postoperative MRI in patients undergoing interstitial laser coagulation thermotherapy of benign prostatic hyperplasia

    SciTech Connect

    Mueller-Lisse, U.G.; Heuck, A.F.; Scheidler, H.J.; Reiser, M.F.

    1996-03-01

    We conducted MRI of the effects of laser-induced thermal therapy (LITT) in benign prostatic hyperplasia (BPH). Eighteen patients (average age 64 years) were examined with MRI 24-48 h before and after LITT of BPH. Sagittal and axial T2-weighted FSE MR images were evaluated for signs of coagulation necrosis in the prostate gland and the presence of intra- and extraprostatic edema. Coagulation areas showed as a hypointense central core with a hyperintense rim. Intraprostatic edema led to a volume increase of 18-108% both in the central and in the total gland. Periprostatic edema was severe in preprostatic and prevesical tissue as well as lateral to the prostate, moderate in the presacral space, and mild perirectally and dorsal to the prostate. Follow-up examinations 2 weeks to 6 months after LITT in five patients showed decrease of coagulation necrosis volume, prostate size, and edema. MRI appears to be a reliable method to monitor LITT effects in patients with BPH. 22 refs., 5 figs., 4 tabs.

  9. Respiratory Antiviral Immunity and Immunobiotics: Beneficial Effects on Inflammation-Coagulation Interaction during Influenza Virus Infection

    PubMed Central

    Zelaya, Hortensia; Alvarez, Susana; Kitazawa, Haruki; Villena, Julio

    2016-01-01

    Influenza virus (IFV) is a major respiratory pathogen of global importance, and the cause of a high degree of morbidity and mortality, especially in high-risk populations such as infants, elderly, and immunocompromised hosts. Given its high capacity to change antigenically, acquired immunity is often not effective to limit IFV infection and therefore vaccination must be constantly redesigned to achieve effective protection. Improvement of respiratory and systemic innate immune mechanisms has been proposed to reduce the incidence and severity of IFV disease. In the last decade, several research works have demonstrated that microbes with the capacity to modulate the mucosal immune system (immunobiotics) are a potential alternative to beneficially modulate the outcome of IFV infection. This review provides an update of the current status on the modulation of respiratory immunity by orally and nasally administered immunobiotics, and their beneficial impact on IFV clearance and inflammatory-mediated lung tissue damage. In particular, we describe the research of our group that investigated the influence of immunobiotics on inflammation–coagulation interactions during IFV infection. Studies have clearly demonstrated that hostile inflammation is accompanied by dysfunctional coagulation in respiratory IFV disease, and our investigations have proved that some immunobiotic strains are able to reduce viral disease severity through their capacity to modulate the immune-coagulative responses in the respiratory tract. PMID:28066442

  10. Current Pathological and Laboratory Considerations in the Diagnosis of Disseminated Intravascular Coagulation

    PubMed Central

    Alhamdi, Yasir; Abrams, Simon T.

    2016-01-01

    Systemically sustained thrombin generation in vivo is the hallmark of disseminated intravascular coagulation (DIC). Typically, this is in response to a progressing disease state that is associated with significant cellular injury. The etiology could be infectious or noninfectious, with the main pathophysiological mechanisms involving cross-activation among coagulation, innate immunity, and inflammatory responses. This leads to consumption of both pro- and anticoagulant factors as well as endothelial dysfunction and disrupted homeostasis at the blood vessel wall interface. In addition to the release of tissue plasminogen activator (tPA) and soluble thrombomodulin (sTM) following cellular activation and damage, respectively, there is the release of damage-associated molecular patterns (DAMPs) such as extracellular histones and cell-free DNA. Extracellular histones are increasingly recognized as significantly pathogenic in critical illnesses through direct cell toxicity, the promotion of thrombin generation, and the induction of neutrophil extracellular trap (NET) formation. Clinically, high circulating levels of histones and histone–DNA complexes are associated with multiorgan failure, DIC, and adverse patient outcomes. Their measurements as well as that of other DAMPs and molecular markers of thrombin generation are not yet applicable in the routine diagnostic laboratory. To provide a practical diagnostic tool for acute DIC, a composite scoring system using rapidly available coagulation tests is recommended by the International Society on Thrombosis and Haemostasis. Its usefulness and limitations are discussed alongside the advances and unanswered questions in DIC pathogenesis. PMID:27578502

  11. NOVEL MICROWAVE FILTER DESIGN TECHNIQUES.

    DTIC Science & Technology

    ELECTROMAGNETIC WAVE FILTERS, MICROWAVE FREQUENCY, PHASE SHIFT CIRCUITS, BANDPASS FILTERS, TUNED CIRCUITS, NETWORKS, IMPEDANCE MATCHING , LOW PASS FILTERS, MULTIPLEXING, MICROWAVE EQUIPMENT, WAVEGUIDE FILTERS, WAVEGUIDE COUPLERS.

  12. NOVEL MICROWAVE FILTER DESIGN TECHNIQUES.

    DTIC Science & Technology

    ELECTRIC FILTERS, MICROWAVE FREQUENCY), (*MICROWAVE EQUIPMENT, ELECTRIC FILTERS), CIRCUITS, CAPACITORS, COILS, RESONATORS, STRIP TRANSMISSION LINES, WAVEGUIDES, TUNING DEVICES, PARAMETRIC AMPLIFIERS, FREQUENCY CONVERTERS .

  13. Seawater Immersion Aggravates Burn Injury Causing Severe Blood Coagulation Dysfunction.

    PubMed

    Yan, Hong; Mao, Qingxiang; Ma, Yongda; Wang, Li; Chen, Xian; Hu, Yi; Ge, Hengjiang

    2016-01-01

    This study aimed to investigate the endothelial function in a canine model of burn injury combined with seawater immersion. The model of burn injury was established. The dogs were randomly divided into four groups including dogs with burn injury (B group), or burn injury combined with seawater immersion (BI group), or only immersion in seawater (I group), or control animals with no injury or immersion (C group). The circulating endothelial cell (CEC) count and coagulation-fibrinolysis parameters were measured. The CEC count in B group increased at 4 h, 7 h, and 10 h after injury and then reduced, whereas it continuously increased to a greater extent in BI group (P < 0.05). The von Willebrand factor (vWF) activity, plasminogen activator inhibitor (PAI-1), and the ratio of thromboxane B2 (TXB2) to 6-keto-prostaglandin F1α (6-K-PGF1α ) in BI group had a marked increase after injury, and the tissue-type plasminogen activator (tPA) in the BI group decreased. Microscope observations revealed thrombus formation in lungs of the animals in BI group, but not in C, I, or B groups. Burn injury causes endothelial dysfunction, and seawater immersion lastingly aggravates this injury, leading to a higher risk of developing thrombosis.

  14. Comparison of coagulants and coagulation aids for treatment of meat processing wastewater by column flotation.

    PubMed

    de Sena, Rênnio F; Moreira, Regina F P M; José, Humberto J

    2008-11-01

    The physicochemical treatment of the wastewater from a meat processing industry was studied using three ferric salts as coagulants in conjunction with four different polymers as coagulation aids by batch column flotation. The effluent was characterized in terms of pH (6.5-6.7), turbidity (1000-12000 NTU), total solids (TS) (2300-7000mgl(-1)), oils and greases (OG) (820-1050mgl(-1)), and biochemical and chemical oxygen demands (BOD(5) and COD) (1200-1760 and 2800-3230mgl(-1)), respectively. The treatments achieved typical organic load reductions of oils and greases, and total solids (up to 85%), as well as biochemical and chemical oxygen demands (between 62.0-78.8% and 74.6-79.5%, respectively). The research also found that the utilization of a column flotation achieved high efficiency of organic matter removal and its operation as a primary treatment showed no significant dependence of pollutant removal and air flow rate.

  15. Chemical sympathectomy attenuates inflammation, glycocalyx shedding and coagulation disorders in rats with acute traumatic coagulopathy.

    PubMed

    Xu, Lin; Yu, Wen-Kui; Lin, Zhi-Liang; Tan, Shan-Jun; Bai, Xiao-Wu; Ding, Kai; Li, Ning

    2015-03-01

    Acute traumatic coagulopathy (ATC) may trigger sympathoadrenal activation associated with endothelial damage and coagulation disturbances. Overexcitation of sympathetic nerve in this state would disrupt sympathetic-vagal balance, leading to autonomic nervous system dysfunction. The aim of this study was to evaluate the autonomic function in ATC and its influence on inflammation, endothelial and coagulation activation. Male Sprague-Dawley rats were randomly assigned to sham, ATC control (ATCC) and ATC with sympathectomy by 6-hydroxydopamine (ATCS) group. Sham animals underwent the same procedure without trauma and bleeding. Following trauma and hemorrhage, rats underwent heart rate variability (HRV) test, which predicts autonomic dysfunction through the analysis of variation in individual R-R intervals. Then, rats were euthanized at baseline, and at 0, 1 and 2 h after shock and blood gas, conventional coagulation test and markers of inflammation, coagulation, fibrinolysis, endothelial damage and catecholamine were measured. HRV showed an attenuation of total power and high frequency, along with a rise of low frequency and low frequency : high frequency ratio in the ATC rats, which both were reversed by sympathectomy in the ATCS group. Additionally, sympathetic denervation significantly suppressed the increase of proinflammatory cytokines, tumor necrosis factor-α and the fibrinolysis markers including tissue-type plasminogen activator and plasmin-antiplasmin complex. Serum catecholamine, soluble thrombomodulin and syndecan-1 were also effectively inhibited by sympathectomy. These data indicated that autonomic dysfunction in ATC involves both sympathetic activation and parasympathetic inhibition. Moreover, sympathectomy yielded anti-inflammatory, antifibrinolysis and endothelial protective effects in rats with ATC. The role of autonomic neuropathy in ATC should be explored further.

  16. [Effect of xuebijing oral effervescent tablet on endotoxin induced fever and disseminated intravascular coagulation rabbit model].

    PubMed

    Guo, Shan-Shan; Gao, Ying-Jie; Tian, Xue-Chuan; Jin, Ya-Hong; Liu, Fang-Zhou; Cui, Xiao-Lan

    2013-08-01

    In order to discover the mechanism of Xuebijing oral effervescent tablet (XBJOET) to treat infectious diseases, the effect of XBJOET on endotoxin induced rabbit fever and disseminated intravascular coagulation (DIC) was investigated. Auricle microcirculation in rabbit was detected by laser speckle blood perfusion imager system; coagulation function was measured by coagulation analyzer, fibrinolytic system was quantified by Elisa assay and micro thrombosis in tissues was observed with HE staining under light microscope. The results demonstrated that the body temperature of rabbit decreased significantly at 1-3 h after administration with 4.8, 2.4 and 1.2 g x kg(-1) XBJOET to endotoxin induced DIC rabbit model, the auricle microcirculation blood flow in model group (54.45 +/- 14.53) PU was lower than that in control group (77.18 +/- 12.32) PU. The auricle microcirculation blood flow increased markedly and there was significant difference between model group and 1.2 g x kg(-1) XBJOET group. There was significant difference between model group and control group in the content of PAI1 and FIB. The PAI1 levels in model and control groups were (30.48 +/- 2.46) ng x mL(-1) and (20.93 +/- 3.25) ng x mL(-1), respectively. The FIB levels in model and control group were (3.34 +/- 1.09) g x L(-1) and (4.84 +/- 1.10) g x L(-1), respectively. The content of PAI1 in rabbit plasma decreased notably, there were significant differences between model group and 4.8, 2.4 g x kg(-1) XBJOET groups. On the contrary the content of FIB increased. XBJOET possessed pharmacological activities of curing infectious fever and DIC, the mechanism of which is related to amelioration of microcirculation disturbance, inhibition of fibrinolytic system activation and coagulation and micro thrombosis elimination.

  17. Optical properties measurement of the laser-ablated tissues for the combined laser ablation with photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Honda, Norihiro; Ishii, Katsunori; Awazu, Kunio

    2012-03-01

    Laser ablation therapy combined with photodynamic therapy (PDT) is studied for treatment of advanced cancers. The clinical outcome of PDT may be improved by the accurate knowledge about the light distribution within tissue. Optical properties [absorption coefficient (μa), scattering coefficient (μs), anisotropy factor (g), refractive index, etc.] of tissues help us realizing a light propagation through the tissue. It is important to understand of the effect of laser coagulation formed by laser ablation to PDT. The aim of this study is to estimate of influence of coagulated region to PDT for effective PDT combined laser ablation therapy. We evaluated the optical property of mouse tumor tissue in native and coagulated state using a double integrating sphere system and an inverse Monte Carlo method in the wavelength range from 350 to 1000 nm. After laser ablation, the μa and reduced scattering coefficient spectra of coagulated tissues were increased in the wavelength range from 350 to 1000 nm. The optical penetration depth of coagulated tissues is 1.2-2.9 times lower than the native state in the wavelength range from 350 to 1000 nm. The intensity of the light energy inside the coagulated tissue falls to about 60% of its original value at the end of coagulated layer. The evaluation of light energy distribution by the determination of the tissues optical properties could be useful for optimization of the treatment procedure in combined laser ablation with PDT.

  18. Optimized alumina coagulants for water treatment

    DOEpatents

    Nyman, May D [Albuquerque, NM; Stewart, Thomas A [Albuquerque, NM

    2012-02-21

    Substitution of a single Ga-atom or single Ge-atom (GaAl.sub.12 and GeAl.sub.12 respectively) into the center of an aluminum Keggin polycation (Al.sub.13) produces an optimal water-treatment product for neutralization and coagulation of anionic contaminants in water. GaAl.sub.12 consistently shows .about.1 order of magnitude increase in pathogen reduction, compared to Al.sub.13. At a concentration of 2 ppm, GaAl.sub.12 performs equivalently to 40 ppm alum, removing .about.90% of the dissolved organic material. The substituted GaAl.sub.12 product also offers extended shelf-life and consistent performance. We also synthesized a related polyaluminum chloride compound made of pre-hydrolyzed dissolved alumina clusters of [GaO.sub.4Al.sub.12(OH).sub.24(H.sub.2O).sub.12].sup.7+.

  19. Management of coagulation abnormalities in liver disease.

    PubMed

    Potze, Wilma; Porte, Robert J; Lisman, Ton

    2015-01-01

    Liver disease is characterized by changes in all phases of hemostasis. These hemostatic alterations were long considered to predispose patients with liver disease towards a bleeding tendency, as they are associated with prolonged conventional coagulation tests. However, these patients may also suffer from thrombotic complications, and we now know that the hemostatic system in patient with liver disease is, in fact, in a rebalanced state. In this review we discuss the concept of rebalanced hemostasis and its implications for clinical management of patients with liver disease. For instance, there is no evidence that the use of prophylactic blood product transfusion prior to invasive procedures reduces bleeding risk. Clinicians should also be aware of the possibility of thrombosis occurring in patients with a liver disease, and regular thrombosis prophylaxis should not be withheld in these patients.

  20. Quinine-Induced Disseminated Intravascular Coagulation

    PubMed Central

    2016-01-01

    Every drug comes with some side effect. It is the benefit/risk ratio that determines the medical use of the drug. Quinine, a known antimalarial drug, has been used for nocturnal leg cramps since the 1930s; it is associated with severe life-threatening hematological and cardiovascular side effects. Disseminated intravascular coagulation (DIC), albeit rare, is a known coagulopathy associated with Quinine. It is imperative to inquire about the Quinine intake in medication history in patients with coagulopathy, as most patients still consider it a harmless home remedy for nocturnal leg cramps. In this report, we present a case of coagulopathy in a middle-aged woman, who gave a history of taking Quinine for nocturnal leg cramps, as her home remedy. Early identification of the offending agent led to the diagnosis, prompt discontinuation of the medication, and complete recovery and prevented the future possibility of recurrence. PMID:27293443

  1. Contact activation of blood-plasma coagulation

    NASA Astrophysics Data System (ADS)

    Golas, Avantika

    Surface engineering of biomaterials with improved hemocompatibility is an imperative, given the widespread global need for cardiovascular devices. Research summarized in this dissertation focuses on contact activation of FXII in buffer and blood plasma frequently referred to as autoactivation. The extant theory of contact activation imparts FXII autoactivation ability to negatively charged, hydrophilic surfaces. According to this theory, contact activation of plasma involves assembly of proteins comprising an "activation complex" on activating surfaces mediated by specific chemical interactions between complex proteins and the surface. This work has made key discoveries that significantly improve our core understanding of contact activation and unravel the existing paradigm of plasma coagulation. It is shown herein that contact activation of blood factor XII (FXII, Hageman factor) in neat-buffer solution exhibits a parabolic profile when scaled as a function of silanized-glass-particle activator surface energy (measured as advancing water adhesion tension t°a=g° Iv costheta in dyne/cm, where g°Iv is water interfacial tension in dyne/cm and theta is the advancing contact angle). Nearly equal activation is observed at the extremes of activator water-wetting properties --36 < t°a < 72 dyne/cm (O° ≤ theta < 120°), falling sharply through a broad minimum within the 20 < t°a < 40 dyne/cm (55° < theta < 75°). Furthermore, contact activation of FXII in buffer solution produces an ensemble of protein fragments exhibiting either procoagulant properties in plasma (proteolysis of blood factor XI or prekallikrein), amidolytic properties (cleavage of s-2302 chromogen), or the ability to suppress autoactivation through currently unknown biochemistry. The relative proportions of these fragments depend on activator surface chemistry/energy. We have also discovered that contact activation is moderated by adsorption of plasma proteins unrelated to coagulation through an

  2. Coagulation fibrinolysis in sickle-cell disease

    PubMed Central

    Gordon, P. A.; Breeze, G. R.; Mann, J. R.; Stuart, J.

    1974-01-01

    A study of fibrinolytic activity in sickle-cell patients during asymptomatic periods has shown a normal fibrinolytic response to exercise and local heat to the arm. During vasoocclusive crises there was no significant decrease in fibrinolytic activity. These results contrast with earlier reports of decreased fibrinolysis during crisis and a suggestion that fibrinolytic activators might be of value in preventing vasoocclusive episodes. Patients in painful crisis showed a significant rise in fibrinogen concentration and fall in platelet count. The former may contribute to localized vascular sludging by increasing whole-blood viscosity, while the latter probably results from local trapping of platelets in areas of sickling or from subsequent splenic sequestration of damaged platelets. There was no evidence of disseminated, as opposed to localized, intravascular coagulation during crisis. PMID:4412492

  3. Effects of Rivaroxaban on Platelet Activation and Platelet–Coagulation Pathway Interaction

    PubMed Central

    Heitmeier, Stefan; Laux, Volker

    2015-01-01

    Introduction: Activation of coagulation and platelets is closely linked, and arterial thrombosis involves coagulation activation as well as platelet activation and aggregation. In these studies, we investigated the possible synergistic effects of rivaroxaban in combination with antiplatelet agents on thrombin generation and platelet aggregation in vitro and on arterial thrombosis and hemostasis in rat models. Materials and Methods: Thrombin generation was measured by the Calibrated Automated Thrombogram method (0.5 pmol/L tissue factor) using human platelet-rich plasma (PRP) spiked with rivaroxaban (15, 30, or 60 ng/mL), ticagrelor (1.0 µg/mL), and acetylsalicylic acid (ASA; 100 µg/mL). Tissue factor-induced platelet aggregation was measured in PRP spiked with rivaroxaban (15 or 30 ng/mL), ticagrelor (1 or 3 µg/mL), or a combination of these. An arteriovenous (AV) shunt model in rats was used to determine the effects of rivaroxaban (0.01, 0.03, or 0.1 mg/kg), clopidogrel (1 mg/kg), ASA (3 mg/kg), and combinations on arterial thrombosis. Results: Rivaroxaban inhibited thrombin generation in a concentration-dependent manner and the effect was enhanced with ticagrelor and ticagrelor plus ASA. Rivaroxaban and ticagrelor also concentration-dependently inhibited tissue factor-induced platelet aggregation, and their combination increased the inhibition synergistically. In the AV shunt model, rivaroxaban dose-dependently reduced thrombus formation. Combining subefficacious or weakly efficacious doses of rivaroxaban with ASA or ASA plus clopidogrel increased the antithrombotic effect. Conclusion: These data indicate that the combination of rivaroxaban with single or dual antiplatelet agents works synergistically to reduce platelet activation, which may in turn lead to the delayed/reduced formation of coagulation complexes and vice versa, thereby enhancing antithrombotic potency. PMID:25848131

  4. Local Recurrence After Hepatic Radiofrequency Coagulation

    PubMed Central

    Mulier, Stefaan; Ni, Yicheng; Jamart, Jacques; Ruers, Theo; Marchal, Guy; Michel, Luc

    2005-01-01

    Objective: The purpose of this study was to analyze the factors that influence local recurrence after radiofrequency coagulation of liver tumors. Summary Background Data: Local recurrence rate varies widely between 2% and 60%. Apart from tumor size as an important risk factor for local recurrence, little is known about the impact of other factors. Methods: An exhaustive literature search was carried out for the period from January 1, 1990 to January 1, 2004. Only series with a minimal follow-up of 6 months and/or mean follow-up of 12 months were included. Univariate and multivariate meta-analyses were carried out. Results: Ninety-five independent series were included, allowing the analysis of the local recurrence rate of 5224 treated liver tumors. In a univariate analysis, tumor-dependent factors with significantly less local recurrences were: smaller size, neuroendocrine metastases, nonsubcapsular location, and location away from large vessels. Physician-dependent favorable factors were: surgical (open or laparoscopic) approach, vascular occlusion, general anesthesia, a 1-cm intentional margin, and a greater physician experience. In a multivariate analysis, significantly less local recurrences were observed for small size (P < 0.001) and a surgical (versus percutaneous) approach (P < 0.001). Conclusions: Radiofrequency coagulation by laparoscopy or laparotomy results in superior local control, independent of tumor size. The percutaneous route should mainly be reserved for patients who cannot tolerate a laparoscopy or laparotomy. The short-term benefits of less invasiveness for the percutaneous route do not outweigh the longer-term higher risk of local recurrence. PMID:16041205

  5. Field-theory methods in coagulation theory

    SciTech Connect

    Lushnikov, A. A.

    2011-08-15

    Coagulating systems are systems of chaotically moving particles that collide and coalesce, producing daughter particles of mass equal to the sum of the masses involved in the respective collision event. The present article puts forth basic ideas underlying the application of methods of quantum-field theory to the theory of coagulating systems. Instead of the generally accepted treatment based on the use of a standard kinetic equation that describes the time evolution of concentrations of particles consisting of a preset number of identical objects (monomers in the following), one introduces the probability W(Q, t) to find the system in some state Q at an instant t for a specific rate of transitions between various states. Each state Q is characterized by a set of occupation numbers Q = (n{sub 1}, n{sub 2}, ..., n{sub g}, ...), where n{sub g} is the total number of particles containing precisely g monomers. Thereupon, one introduces the generating functional {Psi} for the probability W(Q, t). The time evolution of {Psi} is described by an equation that is similar to the Schroedinger equation for a one-dimensional Bose field. This equation is solved exactly for transition rates proportional to the product of the masses of colliding particles. It is shown that, within a finite time interval, which is independent of the total mass of the entire system, a giant particle of mass about the mass of the entire system may appear in this system. The particle in question is unobservable in the thermodynamic limit, and this explains the well-known paradox of mass-concentration nonconservation in classical kinetic theory. The theory described in the present article is successfully applied in studying the time evolution of random graphs.

  6. Nanoparticles and the blood coagulation system. Part II: safety concerns.

    PubMed

    Ilinskaya, Anna N; Dobrovolskaia, Marina A

    2013-06-01

    Nanoparticle interactions with the blood coagulation system can be beneficial or adverse depending on the intended use of a nanomaterial. Nanoparticles can be engineered to be procoagulant or to carry coagulation-initiating factors to treat certain disorders. Likewise, they can be designed to be anticoagulant or to carry anticoagulant drugs to intervene in other pathological conditions in which coagulation is a concern. An overview of the coagulation system was given and a discussion of a desirable interface between this system and engineered nanomaterials was assessed in part I, which was published in the May 2013 issue of Nanomedicine. Unwanted pro- and anti-coagulant properties of nanoparticles represent significant concerns in the field of nanomedicine, and often hamper the development and transition into the clinic of many promising engineered nanocarriers. This part will focus on the undesirable effects of engineered nanomaterials on the blood coagulation system. We will discuss the relationship between the physicochemical properties of nanoparticles (e.g., size, charge and hydrophobicity) that determine their negative effects on the blood coagulation system in order to understand how manipulation of these properties can help to overcome unwanted side effects.

  7. Systemic blood coagulation activation in acute coronary syndromes

    PubMed Central

    Undas, Anetta; Szułdrzyński, Konstanty; Brummel-Ziedins, Kathleen E.; Tracz, Wiesława; Zmudka, Krzysztof

    2009-01-01

    We evaluated systemic alterations to the blood coagulation system that occur during a coronary thrombotic event. Peripheral blood coagulation in patients with acute coronary thrombosis was compared with that in people with stable coronary artery disease (CAD). Blood coagulation and platelet activation at the microvascular injury site were assessed using immunochemistry in 28 non-anticoagulated patients with acute myocardial infarction (AMI) versus 28 stable CAD patients matched for age, sex, risk factors, and medications. AMI was associated with increased maximum rates of thrombin-antithrombin complex generation (by 93.8%; P < .001), thrombin B-chain formation (by 57.1%; P < .001), prothrombin consumption (by 27.9%; P = .012), fibrinogen consumption (by 27.0%; P = .02), factor (f) Va light chain generation (by 44.2%; P = .003), and accelerated fVa inactivation (by 76.1%; P < .001), and with enhanced release of platelet-derived soluble CD40 ligand (by 44.4%; P < .001). FVa heavy chain availability was similar in both groups because of enhanced formation and activated protein C (APC)–mediated destruction. The velocity of coagulant reactions in AMI patients showed positive correlations with interleukin-6. Heparin treatment led to dampening of coagulant reactions with profiles similar to those for stable CAD. AMI-induced systemic activation of blood coagulation markedly modifies the pattern of coagulant reactions at the site of injury in peripheral vessels compared with that in stable CAD patients. PMID:18931343

  8. Variable frequency microwave heating apparatus

    DOEpatents

    Bible, Don W.; Lauf, Robert J.; Johnson, Arvid C.; Thigpen, Larry T.

    1999-01-01

    A variable frequency microwave heating apparatus (10) designed to allow modulation of the frequency of the microwaves introduced into a multi-mode microwave cavity (34) for testing or other selected applications. The variable frequency microwave heating apparatus (10) includes a microwave signal generator (12) and a high-power microwave amplifier (20) or a high-power microwave oscillator (14). A power supply (22) is provided for operation of the high-power microwave oscillator (14) or microwave amplifier (20). A directional coupler (24) is provided for detecting the direction and amplitude of signals incident upon and reflected from the microwave cavity (34). A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

  9. Variable frequency microwave heating apparatus

    SciTech Connect

    Bible, D.W.; Lauf, R.J.; Johnson, A.C.; Thigpen, L.T.

    1999-10-05

    A variable frequency microwave heating apparatus (10) designed to allow modulation of the frequency of the microwaves introduced into a multi-mode microwave cavity (34) for testing or other selected applications. The variable frequency microwave heating apparatus (10) includes a microwave signal generator (12) and a high-power microwave amplifier (20) or a high-power microwave oscillator (14). A power supply (22) is provided for operation of the high-power microwave oscillator (14) or microwave amplifier (20). A directional coupler (24) is provided for detecting the direction and amplitude of signals incident upon and reflected from the microwave cavity (34). A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

  10. Coaxial microwave plasma source

    SciTech Connect

    Gritsinin, S. I.; Gushchin, P. A.; Davydov, A. M.; Kossyi, I. A.; Kotelev, M. S.

    2011-11-15

    Physical principles underlying the operation of a pulsed coaxial microwave plasma source (micro-wave plasmatron) are considered. The design and parameters of the device are described, and results of experimental studies of the characteristics of the generated plasma are presented. The possibility of application of this type of plasmatron in gas-discharge physics is discussed.

  11. Active microwave water equivalence

    NASA Technical Reports Server (NTRS)

    Boyne, H. S.; Ellerbruch, D. A.

    1980-01-01

    Measurements of water equivalence using an active FM-CW microwave system were conducted over the past three years at various sites in Colorado, Wyoming, and California. The measurement method is described. Measurements of water equivalence and stratigraphy are compared with ground truth. A comparison of microwave, federal sampler, and snow pillow measurements at three sites in Colorado is described.

  12. Microwave processing of ceramics

    SciTech Connect

    Katz, J.D.

    1993-01-01

    Recent work in the areas of microwave processing and joining of ceramics is briefly reviewed. Advantages and disadvantages of microwave processing as well as some of the current issues in the field are discussed. Current state and potential for future commercialization of this technology is also addressed.

  13. Microwave processing of ceramics

    SciTech Connect

    Katz, J.D.

    1993-04-01

    Recent work in the areas of microwave processing and joining of ceramics is briefly reviewed. Advantages and disadvantages of microwave processing as well as some of the current issues in the field are discussed. Current state and potential for future commercialization of this technology is also addressed.

  14. Television Microwave--1971.

    ERIC Educational Resources Information Center

    Peterson, Roger E.

    Since it became a reality just before World War II, terrestrial microwave has improved in systems and equipments, but with the improvements have come higher costs. Television microwave costs are so high because users are demanding more capability, land prices have increased, operating costs are higher, and there is frequency congestion along many…

  15. Microwave device investigations

    NASA Technical Reports Server (NTRS)

    Choudhury, K. K. D.; Haddad, G. I.; Kwok, S. P.; Masnari, N. A.; Trew, R. J.

    1972-01-01

    Materials, devices and novel schemes for generation, amplification and detection of microwave and millimeter wave energy are studied. Considered are: (1) Schottky-barrier microwave devices; (2) intermodulation products in IMPATT diode amplifiers; and (3) harmonic generation using Read diode varactors.

  16. MICROWAVES IN ORGANIC SYNTHESIS

    EPA Science Inventory

    The effect of microwaves, a non-ionizing radiation, on organic reactions is described both in polar solvents and under solvent-free conditions. The special applications are highlighted in the context of solventless organic synthesis which involve microwave (MW) exposure of neat r...

  17. [Argon plasma coagulation (APC): a new mode in gastrointestinal endoscopy--first experience].

    PubMed

    Dajcman, D; Skalicky, M; Pernat, C; Pocajt, M

    2001-01-01

    Argon plasma coagulation (APC) is a new method of non-contact electrocoagulation in which current is applied to tissues by means of ionised argon gas (argon plasma). The development of special applicators has made this method applicable for gastrointestinal endoscopy. The primary indication for APC is the treatment of hemorrhage in the gastrointestinal tract. APC has been proven to be highly effective and easily used, with clear advantages over previously used methods. This article describes the introduction of APC in Slovenia and the first experiences with this method in the clinical department of internal medicine in Maribor.

  18. Microwave hydrology: A trilogy

    NASA Technical Reports Server (NTRS)

    Stacey, J. M.; Johnston, E. J.; Girard, M. A.; Regusters, H. A.

    1985-01-01

    Microwave hydrology, as the term in construed in this trilogy, deals with the investigation of important hydrological features on the Earth's surface as they are remotely, and passively, sensed by orbiting microwave receivers. Microwave wavelengths penetrate clouds, foliage, ground cover, and soil, in varying degrees, and reveal the occurrence of standing liquid water on and beneath the surface. The manifestation of liquid water appearing on or near the surface is reported by a microwave receiver as a signal with a low flux level, or, equivalently, a cold temperature. Actually, the surface of the liquid water reflects the low flux level from the cosmic background into the input terminals of the receiver. This trilogy describes and shows by microwave flux images: the hydrological features that sustain Lake Baykal as an extraordinary freshwater resource; manifestations of subsurface water in Iran; and the major water features of the Congo Basin, a rain forest.

  19. Microwave ion source

    SciTech Connect

    Leung, Ka-Ngo; Reijonen, Jani; Thomae, Rainer W.

    2005-07-26

    A compact microwave ion source has a permanent magnet dipole field, a microwave launcher, and an extractor parallel to the source axis. The dipole field is in the form of a ring. The microwaves are launched from the middle of the dipole ring using a coaxial waveguide. Electrons are heated using ECR in the magnetic field. The ions are extracted from the side of the source from the middle of the dipole perpendicular to the source axis. The plasma density can be increased by boosting the microwave ion source by the addition of an RF antenna. Higher charge states can be achieved by increasing the microwave frequency. A xenon source with a magnetic pinch can be used to produce intense EUV radiation.

  20. Argon laser photo-coagulation complications in diabetic retinopathy.

    PubMed

    Pavljasević, Suzana; Pranjić, Nurka; Sarajlić, Dzevdet

    2004-05-01

    Diabetic retinopathy is a disease based on vascular genesis that begins as microangiopathy and develops into macroangioapthy preceded by fibroproliferation changes. According to histo- pathological changes, diabetic retinopathy is divided into nonproliferative, pre-proliferative and proliferative diabetic retinopathy. Possibilities and needs for photo-coagulation in the earlier and later changes in retina reduce the meaning of conservative treatment. Laser photo-coagulation with therapeutical may cause unwanted and damaging effects, as well. Complications diagnosed in diabetic retinopathy, such as cataract, secondary glaucoma, central retinal vein thrombosis, haemophthalmus, are much more frequent in patients with laser photo-coagulation treatment.

  1. Changes in the human blood coagulating system during prolonged hypokinesia

    NASA Technical Reports Server (NTRS)

    Filatova, L. M.; Anashkin, O. D.

    1978-01-01

    Changes in the coagulating system of the blood were studied in six subjects during prolonged hypokinesia. Thrombogenic properties of the blood rose in all cases on the 8th day. These changes are explained by stress reaction due to unusual conditions for a healthy person. Changes in the blood coagulating system in the group subjected to physical exercise and without it ran a practically parallel course. Apparently physical exercise is insufficient to prevent such changes that appear in the coagulating system of the blood during prolonged hypokinesia.

  2. Implementation of a microcontroller-based semi-automatic coagulator.

    PubMed

    Chan, K; Kirumira, A; Elkateeb, A

    2001-01-01

    The coagulator is an instrument used in hospitals to detect clot formation as a function of time. Generally, these coagulators are very expensive and therefore not affordable by a doctors' office and small clinics. The objective of this project is to design and implement a low cost semi-automatic coagulator (SAC) prototype. The SAC is capable of assaying up to 12 samples and can perform the following tests: prothrombin time (PT), activated partial thromboplastin time (APTT), and PT/APTT combination. The prototype has been tested successfully.

  3. Electromagnetic Initiation and Propagation of Bipolar Radiofrequency Tissue Reactions via Invasive Non-Insulated Microneedle Electrodes

    PubMed Central

    Na, Jongju; Zheng, Zhenlong; Dannaker, Christopher; Lee, Sang Eun; Kang, Jin-Soo; Cho, Sung Bin

    2015-01-01

    Radiofrequency (RF) energy can be emitted into the skin, either non- or invasively, via a monopolar mode that utilizes an active electrode and a grounded electrode or via a bipolar mode that employs two active electrodes. In this experimental study of RF tissue reactions, bipolar RF energy was emitted in vivo to micropig skin at varying microneedle penetration depths, signal amplitudes, and conduction times. Immediately after RF treatment, skin samples exhibited RF-induced coagulation columns of thermal injury, separately generated around each microneedle in the dermis. In ex vivo bovine liver tissue, the thermal coagulation columns were found to be concentrated maximally around the pointed tips of each electrode. After a RF conduction time of 2 seconds, the individual areas of thermal coagulation began to converge with neighboring RF-induced coagulation columns; the convergence of coagulation columns was found to start from the tips of neighboring electrodes. PMID:26563971

  4. Viability and antigenicity of anisakis simplex after conventional and microwave heating at fixed temperatures.

    PubMed

    Vidaček, Sanja; De Las Heras, Cristina; Solas, Maria Teresa; García, Maria Luisa; Mendizábal, Angel; Tejada, Margarita

    2011-12-01

    Inactivation of parasites in food by microwave treatment may vary due to differences in the characteristics of microwave ovens and food properties. Microwave treatment in standard domestic ovens results in hot and cold spots, and the microwaves do not penetrate all areas of the samples depending on the thickness, which makes it difficult to compare microwave with conventional heat treatments. The viability of Anisakis simplex (isolated larvae and infected fish muscle) heated in a microwave oven with precise temperature control was compared with that of larvae heated in a water bath to investigate any additional effect of the microwaves. At a given temperature, less time was required to kill the larvae by microwaves than by heated water. Microwave treatment killed A. simplex larvae faster than did conventional cooking when the microwaves fully penetrated the samples and resulted in fewer changes in the fish muscle. However, the heat-stable allergen Ani s 4 was detected by immunohistochemistry in the fish muscle after both heat treatments, even at 70°C, suggesting that Ani s 4 allergens were released from the larvae into the surrounding tissue and that the tissues retained their allergenicity even after the larvae were killed by both heat treatments. Thus, microwave cooking will not render fish safe for individuals already sensitized to A. simplex heat-resistant allergens.

  5. Influence of Enteromorpha polysaccharides on variation of coagulation behavior, flocs properties and membrane fouling in coagulation-ultrafiltration process.

    PubMed

    Zhao, Shuang; Gao, Baoyu; Yue, Qinyan; Sun, Shenglei; Song, Wuchang; Jia, Ruibao

    2015-03-21

    Enteromorpha polysaccharides (Ep) were used as a new coagulant aid together with polyaluminum chloride (PACl) in coagulation-ultrafiltration process to purify Yellow River water. The evolution of flocs size, growth rate, strength, recoverability and fractal structure due to Ep addition were systematically studied in this paper. On this basis, membrane fouling caused by the coagulation effluents of PACl and Ep were also investigated. Results indicated that Ep addition lead to 20% increase in coagulation performance, and meanwhile generate flocs with bigger sizes, faster growth rates and higher recovery abilities. Additionally, the flocs formed by PACl presented more compact structure with a larger D(f) value, while much looser flocs were obtained when Ep was added. Results of ultrafiltration experiments implied that with Ep addition, membrane fouling could be significantly reduced due to large size and loosely structures of flocs in coagulation effluents. Considering both the coagulation efficiency and ultrafiltration membrane performance, 0.2 mg/L Ep was determined as the optimal dosage in coagulation-ultrafiltration process in this study.

  6. New bipolar tissue ligator combines constant tissue compression and temperature guidance: histologic study and implications for treatment of hemorrhoids

    PubMed Central

    Piskun, Gregory; Tucker, Robert

    2012-01-01

    Background Several minimally invasive technologies are available to treat common soft tissue lesions including symptomatic hemorrhoids. The use of energy to deliver heat and coagulate target lesions is commonly practiced. This study compares the histologic effects produced on intestinal tissues by two energy-based systems which employ different approaches of heat delivery. Methods Two heat delivery systems were evaluated in vivo in a single porcine subject: infrared coagulator and bipolar tissue ligator utilizing constant tissue compression and temperature guidance. Eighteen treatment sites divided into three groups of six were assessed. Treatment site temperature was measured and the effects of thermal treatment in the mucosa, submucosa, submucosal vessels, and muscularis layer were scored. Lateral thermal spread beyond the energy application site was also assessed. Results Treatment site temperatures were much lower in the bipolar ligator group than in the infrared coagulator group. The mucosal and submucosal tissue changes observed in tissues treated with infrared energy and bipolar energy at 55°C were similar. Both the mucosal and submucosal tissue changes with bipolar energy at 50°C were significantly less. Conclusion Both devices achieved similar histologic results. However, the unique design of the bipolar ligator, which allows consistent capture, constant compression, and temperature monitoring of target tissue, accomplished the desired histologic changes with less muscular damage at much lower temperatures than the infrared coagulator. The use of bipolar ligation could offer clinical advantages such as reduced patient pain and a minimized chance of heat-related collateral tissue damage. PMID:23152714

  7. The Interplay between Inflammation, Coagulation and Endothelial Injury in the Early Phase of Acute Pancreatitis: Clinical Implications.

    PubMed

    Dumnicka, Paulina; Maduzia, Dawid; Ceranowicz, Piotr; Olszanecki, Rafał; Drożdż, Ryszard; Kuśnierz-Cabala, Beata

    2017-02-08

    Acute pancreatitis (AP) is an inflammatory disease with varied severity, ranging from mild local inflammation to severe systemic involvement resulting in substantial mortality. Early pathologic events in AP, both local and systemic, are associated with vascular derangements, including endothelial activation and injury, dysregulation of vasomotor tone, increased vascular permeability, increased leukocyte migration to tissues, and activation of coagulation. The purpose of the review was to summarize current evidence regarding the interplay between inflammation, coagulation and endothelial dysfunction in the early phase of AP. Practical aspects were emphasized: (1) we summarized available data on diagnostic usefulness of the markers of endothelial dysfunction and activated coagulation in early prediction of severe AP; (2) we reviewed in detail the results of experimental studies and clinical trials targeting coagulation-inflammation interactions in severe AP. Among laboratory tests, d-dimer and angiopoietin-2 measurements seem the most useful in early prediction of severe AP. Although most clinical trials evaluating anticoagulants in treatment of severe AP did not show benefits, they also did not show significantly increased bleeding risk. Promising results of human trials were published for low molecular weight heparin treatment. Several anticoagulants that proved beneficial in animal experiments are thus worth testing in patients.

  8. The Interplay between Inflammation, Coagulation and Endothelial Injury in the Early Phase of Acute Pancreatitis: Clinical Implications

    PubMed Central

    Dumnicka, Paulina; Maduzia, Dawid; Ceranowicz, Piotr; Olszanecki, Rafał; Drożdż, Ryszard; Kuśnierz-Cabala, Beata

    2017-01-01

    Acute pancreatitis (AP) is an inflammatory disease with varied severity, ranging from mild local inflammation to severe systemic involvement resulting in substantial mortality. Early pathologic events in AP, both local and systemic, are associated with vascular derangements, including endothelial activation and injury, dysregulation of vasomotor tone, increased vascular permeability, increased leukocyte migration to tissues, and activation of coagulation. The purpose of the review was to summarize current evidence regarding the interplay between inflammation, coagulation and endothelial dysfunction in the early phase of AP. Practical aspects were emphasized: (1) we summarized available data on diagnostic usefulness of the markers of endothelial dysfunction and activated coagulation in early prediction of severe AP; (2) we reviewed in detail the results of experimental studies and clinical trials targeting coagulation-inflammation interactions in severe AP. Among laboratory tests, d-dimer and angiopoietin-2 measurements seem the most useful in early prediction of severe AP. Although most clinical trials evaluating anticoagulants in treatment of severe AP did not show benefits, they also did not show significantly increased bleeding risk. Promising results of human trials were published for low molecular weight heparin treatment. Several anticoagulants that proved beneficial in animal experiments are thus worth testing in patients. PMID:28208708

  9. Effect of copper(II) on natural organic matter removal during drinking water coagulation using aluminum-based coagulants.

    PubMed

    Liu, Guojing; Zhang, Xiangru; Talley, Jeffrey W

    2007-06-01

    Coagulation has been proposed as a best available technology for controlling natural organic matter (NOM) during drinking water treatment. The presence of heavy metals such as copper(II) in source water, which may form copper-NOM complexes and/or interact with a coagulant, may pose a potential challenge on the coagulation of NOM. In this work, the effect of copper(II) on NOM removal by coagulation using alum or PAX-18 (a commercial polymerized aluminum chloride from Kemiron Inc., Bartow, Florida) was examined. The results show that the presence of 1 to 10 mg/L of copper(H) in the simulated waters improved the total organic carbon (TOC) removal by up to 25% for alum coagulation and by up to 22% for PAX-18 coagulation. The increased NOM removal with the presence of copper(II) in the waters can most likely be ascribed to the formation copper-NOM complexes that may be more adsorbable on aluminum precipitates and to the formation of copper(II) co-precipitates that may also adsorb NOM. The presence of 1 to 5 mg/L of copper(I) in the waters containing 3 mg/L NOM as carbon was reduced below the maximum contaminant level goal (1.3 mg/L as copper) using either coagulant. The results suggest that the presence of copper(H) in source water may not adversely affect the NOM removal by coagulation. A good linear correlation was observed between the TOC removal efficiency and the log-total moles of the precipitated metals, which include the metal ion from a coagulant and the divalent metal ion(s) in source water.

  10. Removal of titanium dioxide nanoparticles by coagulation: effects of coagulants, typical ions, alkalinity and natural organic matters.

    PubMed

    Wang, H T; Ye, Y Y; Qi, J; Li, F T; Tang, Y L

    2013-01-01

    To investigate the possibility of removing titanium dioxide nanoparticles (TiO2 NPs) from water by coagulation, as well as to find the optimal coagulant and experimental conditions for TiO2 NP removal, four types of coagulant were adopted: polyferric sulfate (PFS), ferric chloride (FeCl3), polyaluminum chloride (PACl), and alum (Al2(SO4)3). It was found that the removal of TiO2 NPs by coagulation was affected by ionic strength, alkalinity, as well as types and dosages of coagulants. PFS and FeCl3 achieved much higher removal efficiency of TiO2 NPs than PACl and Al2(SO4)3 did. For 30 mg/L TiO2 NPs, a dosage of 0.3 mM PFS (as Fe) achieved 84% removal after coagulation followed by 30 min settlement. Optimal ionic strength (0.1 M NaCl or 0.03 M CaCl2) is of vital importance for the performance of PFS. Na2SO4 is unfavorable for the performance of PFS. Optimal alkalinity (0.01-0.03 M NaHCO3) is necessary for FeCl3 to remove TiO2 NPs. Natural organic matter, as represented by humic acid (HA) up to 11 mg/L, reduces the removal of TiO2 NPs by coagulation. These findings indicate that coagulation is a good option for the removal of TiO2 NPs from water, and more attention should be paid to the effects of water quality when using coagulation to remove TiO2 NPs from aqueous matrices. This provides a possible solution to alleviate the potential hazard caused by TiO2 NPs.

  11. Strong enhancement of dispersion forces from microwave radiation

    NASA Astrophysics Data System (ADS)

    Sernelius, B. E.

    2002-11-01

    We have studied non-thermal effects of microwave radiation on the forces between objects. This is the first step in a study of possible effects of microwave radiation from cellular phones on biological tissue. We have used a simplified model for human blood cells in blood. We find for the normal radiation level of cellular phones an enhancement of the attractive force with ten orders of magnitude as compared to the corresponding effect at thermal radiation.

  12. Comparison of thermal coagulation profiles for bipolar forceps with different cooling mechanisms in a porcine model of spinal surgery

    PubMed Central

    Chen, Roland K.; Than, Khoi D.; Wang, Anthony C.; Park, Paul; Shih, Albert J.

    2013-01-01

    Background: Coagulation accomplished using bipolar forceps is common in neurosurgery. Control of thermal spread from the forceps tips into surrounding neural tissues is a persistent concern, as neural tissues are especially vulnerable to heat injury. The purpose of our investigation was to compare the efficacy of cooling mechanisms for four different bipolar forceps and to understand thermal spread when coagulating vessels on the spinal cord. Methods: Immediately following euthanasia, the dura mater of an ex vivo porcine model was opened to expose vessels on the spinal cord for coagulation. Temperature profiles were measured at generator power of 25 W and at fixed 5-second activation times. The bipolar forceps used in this study included regular stainless steel, titanium, heat-pipe embedded, and SILVERGlide forceps. Temperature was measured by micro-thermistor at the midpoint between the bipolar tips, and 1 and 2 mm away from the midpoint along the centerline. Statistical analysis was performed to evaluate temperature differences. Results: Temperature profiles indicated that heat-pipe embedded forceps create the least amount of temperature increase and the highest normalized temperature decreasing slope after activation. The decreasing slope of SILVERGlide forceps is slightly higher than that of regular stainless steel forceps. Conclusions: Bipolar forceps incorporating either heat-pipe embedded technology or SILVERGlide coating can effectively limit excessive thermal spread, thus decreasing potential injury to adjacent tissues when compared with standard stainless steel and titanium bipolar forceps. Of the two, heat-pipe embedded technology appeared safest, having better cooling efficiency at higher temperature. PMID:24083049

  13. Influence of natural coagulants on isoflavones and antioxidant activity of tofu.

    PubMed

    Rekha, C R; Vijayalakshmi, G

    2010-08-01

    Tofu (instead of preparing using synthetic coagulant) was prepared using coagulants of plant origin (Citrus limonum, Garcinia indica, Tamarindus indica, Phyllanthus acidus and Passiflora edulis). Total crude protein and fat contents were highest in tofu prepared using G. indica and T. indica (72.5% dbw) compared to synthetic coagulant. Tofu prepared with natural coagulants had signifi cantly higher antioxidant activity compared to synthetic coagulant. Bioconversion of isoflavone glucosides (daidzin and genistin) into their corresponding bioactive aglycones (daidzein and genistein) was observed in tofu. The difference between glucosides and aglycones contents in soy milk was significant but there was not much difference in tofu coagulated with synthetic and natural coagulants.

  14. Microwave bonding of MEMS component

    NASA Technical Reports Server (NTRS)

    Barmatz, Martin B. (Inventor); Mai, John D. (Inventor); Jackson, Henry W. (Inventor); Budraa, Nasser K. (Inventor); Pike, William T. (Inventor)

    2005-01-01

    Bonding of MEMs materials is carried out using microwave. High microwave absorbing films are placed within a microwave cavity, and excited to cause selective heating in the skin of the material. This causes heating in one place more than another. Thereby minimizing the effects of the bonding microwave energy.

  15. Impacts of epichlorohydrin-dimethylamine on coagulation performance and membrane fouling in coagulation/ultrafiltration combined process with different Al-based coagulants.

    PubMed

    Bu, Fan; Gao, Baoyu; Li, Ruihua; Sun, Shenglei; Yue, Qinyan

    2016-09-01

    Two kinds of aluminum-based coagulants and epichlorohydrin-dimethylamine (DAM-ECH) were used in the treatment of humic acid-kaolin simulated water by coagulation-ultrafiltration (C-UF) hybrid process. Coagulation performance, floc characteristics, including floc size, compact degree, and strength were investigated in this study. Ultrafiltration experiments were conducted by a dead-end batch unit to implement the resistance analyses to explore the membrane fouling mechanisms. Results showed that DAM-ECH aid significantly increased the UV254 and DOC removal efficiencies and contributed to the formation of larger and stronger flocs with a looser structure. Aluminum chloride (Al) gave rise to better coagulation performance with DAM-ECH compared with poly aluminum chloride (PACl). The consequences of ultrafiltration experiments showed that DAM-ECH aid could reduce the membrane fouling mainly by decreasing the cake layer resistance. The flux reductions for PACl, Al/DAM-ECH (dosing both Al and DAM-ECH) and PACl/DAM-ECH (dosing both PACl and DAM-ECH) were 62%, 56% and 44%, respectively. Results of this study would be beneficial for the application of PACl/DAM-ECH and Al/DAM-ECH composite coagulants in water treatment processes.

  16. Gold Nanoparticle Microwave Synthesis

    SciTech Connect

    Krantz, Kelsie E.; Christian, Jonathan H.; Coopersmith, Kaitlin; Washington, II, Aaron L.; Murph, Simona H.

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  17. Electro-coagulation treatment of oily wastewater with sludge analysis.

    PubMed

    Ibrahim, Dhorgham Skban; Sakthipriya, N; Balasubramanian, N

    2012-01-01

    Experiments were carried out in a batch reactor to treat the oily effluent by electro-coagulation. The influence of operating parameters such as applied current, type of electrode and electrolysis time on electro-coagulation efficiency has been critically examined. The maximum percentage removal of chemical oxygen demand (COD) was 94% under optimum experimental conditions of pH 6.7, current density 6 mA/cm², electrolysis time 40 min, and using mild steel as anode. The remaining sludge in the reactor was analyzed by energy disperse analysis of X-rays (EDAX) and scanning electron microscope (SEM) analysis. The analysis confirms that the oily pollutant was removed by electroflotation and adsorption of the oily particles of precipitate during the electro-coagulation process. Electro-coagulation can be used as an efficient treatment technique for oily wastewater.

  18. CARDIOVASCULAR AND BLOOD COAGULATION EFFECTS OF PULMONARY ZINC EXPOSURE

    EPA Science Inventory

    Cardiovascular damage induced by pulmonary exposure to environmental chemicals can result from direct action or, secondarily, from pulmonary injury. We have developed a rat model of pulmonary exposure to zinc to demonstrate cardiac, coagulative, and fibrinolytic alterations. Mal...

  19. Screening for coagulation disorders in patients with ischemic stroke.

    PubMed

    de Lau, Lonneke Ml; Leebeek, Frank Wg; de Maat, Moniek Pm; Koudstaal, Peter J; Dippel, Diederik Wj

    2010-08-01

    The role of coagulation disorders in the pathogenesis of (recurrent) ischemic stroke is uncertain. Therefore, the clinical utility of screening patients with ischemic stroke for these conditions and the therapeutic implications of a detected coagulation disorder in a patient who experienced ischemic stroke are uncertain. We reviewed the currently available data on the relationship between various inherited and acquired coagulation abnormalities (factor V Leiden and prothrombin G20210A mutations, deficiencies of protein C, protein S and anti-thrombin, hyperhomocysteinemia, the antiphospholipid syndrome and increased levels of fibrinogen) and ischemic stroke. Based on the existing evidence we discuss the usefulness of screening stroke patients for prothrombotic conditions and current recommendations regarding the optimal management of ischemic stroke patients in whom a coagulation disorder is found.

  20. Carbon dioxide pressure-induced coagulation of microalgae.

    PubMed

    Lee, Roland; Jessop, Philip G; Champagne, Pascale

    2015-12-28

    The move to a low-carbon economy has generated renewed interest in microalgae for the production of biofuels with the potential mutual benefit of wastewater treatment. However, harvesting has been identified as a limiting factor to the economic viability of this process. This paper explores the harvesting of microalgae using high-pressure gas without the addition of coagulants. Coagulation of microalgae under high-pressure gas was found to be an efficient method to separate algae from suspension. The critical coagulation pressures (CCPs) for H(2) and CO(2) were determined to be 6.1 and 6.2 MPa, respectively. The CO(2)-induced decrease in solution pH positively influenced coagulation rates, without appearing to affect the CCP. This approach could be beneficial for the economic removal of microalgae from solution for the production of both biofuels and biomedical compounds without the addition of non-environmentally friendly chemicals.

  1. Surgical Coagulator With Carbon Dioxide Laser For Gynecology

    NASA Astrophysics Data System (ADS)

    Wolinski, Wieslaw; Kazmirowski, Antoni; Korobowicz, Witold; Olborski, Zbigniew

    1987-10-01

    The technical data and parameters of the CO2 surgical laser for gynecology are given. Coagulator was designed and constructed in Institute of Microelectronics and Optoelectronics Warsaw Technical University.

  2. Three-dimensional microwave imaging with incorporated prior structural information

    NASA Astrophysics Data System (ADS)

    Golnabi, Amir H.; Meaney, Paul M.; Epstein, Neil R.; Paulsen, Keith D.

    2012-03-01

    Microwave imaging for biomedical applications, especially for early detection of breast cancer and effective treatment monitoring, has attracted increasing interest in last several decades. This fact is due to the high contrast between the dielectric properties of the normal and malignant breast tissues at microwave frequencies. The available range of dielectric properties for different soft tissue can provide important functional information about tissue health. Nonetheless, one of the limiting weaknesses of microwave imaging is that unlike conventional modalities, such as X-ray CT or MRI, it inherently cannot provide high-resolution images. The conventional modalities can produce highly resolved anatomical information but often cannot provide the functional information required for diagnoses. Previously, we have developed a regularization strategy that can incorporate prior anatomical information from MR or other sources and use it in a way to refine the resolution of the microwave images, while also retaining the functional nature of the reconstructed property values. In the present work, we extend the use of prior structural information in microwave imaging from 2D to 3D. This extra dimension adds a significant layer of complexity to the entire image reconstruction procedure. In this paper, several challenges with respect to the 3D microwave imaging will be discussed and the results of a series of 3D simulation and phantom experiments with prior structural information will be studied.

  3. Coagulation and flocculation study of iron ore fines

    SciTech Connect

    Singh, B.P.; Besra, L.; Ravi Prasad, A.

    1999-03-01

    A comparative study of the flocculation and coagulation response of an iron ore fines suspension has been carried out, and the extent of flocculation has been assessed by measurement of electrophoretic mobility, supernatant clarity, and settling rate. Of the several commercial flocculants and polyelectrolyte studied, the combination of medium molecular weight anionic flocculants Magnafloc 1011 and Rishfloc 258 (1:1), and coagulant aluminum nitrate was most effective in terms of enhancing settling rate and supernatant clarity.

  4. A new coagulation defect associated with a case of melanomatosis.

    PubMed Central

    Phillips, J D; O'Shea, M J

    1977-01-01

    A marked abnormality of the intrinsic coagulation system was observed in a patient with melanomatosis and frank melanuria. With successful treatment of the tumour there was a parallel improvement in the clotting abnormality. This defect was shown to be a deficiency of factor XI together with a previously unrecognised factor. This is distinct from either Fletcher or Fitzgerald factors and appears to act between factors XI and X in the coagulation sequence. PMID:874111

  5. PLASMA COAGULATION BY ORGANISMS OTHER THAN STAPHYLOCOCCUS AUREUS.

    PubMed

    BAYLISS, B G; HALL, E R

    1965-01-01

    Bayliss, Berenice G. (Washington State University, Pullman), and Elizabeth R. Hall. Plasma coagulation by organisms other than Staphylococcus aureus. J. Bacteriol. 89:101-105. 1965.-Approximately 200 organisms were investigated for their ability to clot human and rabbit plasma. Various anticoagulants were used in preparing the plasma: acid-citrate-dextrose, ethylenediaminetetraacetate, balanced oxalate, potassium and sodium oxalates, and heparin. Twelve organisms were found which coagulated citrated plasma in less than 8 hr: four strains of Streptococcus faecalis; two strains of S. faecalis var. zymogenes; three strains of S. faecalis var. liquefaciens; and one strain each of S. pyogenes, Escherichia coli, and Serratia marcescens. Six strains of coagulase-positive Staphylococcus were selected for use as controls. Experiments were performed to determine the mechanism by which these microorganisms coagulated citrated plasma. As this was the only plasma clotted, it was presumed that the citrate was utilized by the microorganisms, thereby releasing the calcium which was then made available so that normal physiological clotting could occur. To test this hypothesis, a chromatographic method was employed to determine the presence or absence of citrate. Coagulation tests, by use of increasing amounts of citrate, showed a linear relationship between the amount of citrate in the plasma and the coagulation time. It was demonstrated that the organisms must be actively metabolizing to clot citrated plasma. Proof for this was obtained by using a cell-free filtrate, to which thimerosal had been added to inhibit growth, instead of whole cultures for the coagulation test. Only the coagulase-positive staphylococci coagulated the citrated plasma under these conditions. From the results obtained, it was concluded that plasma coagulation by these organisms was by citrate utilization.

  6. The Continuous Coagulation-FragmentationEquations with Diffusion

    NASA Astrophysics Data System (ADS)

    Laurençot, Philippe; Mischler, Stéphane

    Existence of global weak solutions to the continuous coagulation-fragmentation equations with diffusion is investigated when the kinetic coefficients satisfy a detailed balance condition or the coagulation coefficient enjoys a monotonicity condition. Our approach relies on weak and strong compactness methods in L1 in the spirit of the DiPerna-Lions theory for the Boltzmann equation. Under the detailed balance condition the large-time behaviour is also studied.

  7. Removal of Arsenic from Drinking Water by Adsorption and Coagulation

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Sugita, H.; Hara, J.; Takahashi, S.

    2013-12-01

    Removal of arsenic from drinking water has been an important issue worldwide, which has attracted greater attentions in recent years especially for supplying safe drinking water in developing countries. Although many kinds of treatment approaches that are available or applicable both in principle and practice, such as adsorption, coagulation, membrane filtration, ion exchange, biological process, electrocoagulation and so on, the first 2 approaches (i.e., adsorption and coagulation) are most promising due to the low-cost, high-efficiency, simplicity of treating systems, and thus can be practically used in developing countries. In this study, a literature survey on water quality in Bangladesh was performed to understand the ranges of arsenic concentration and pH of groundwater in Bangladesh. A series of tests were then organized and performed to investigate the effects of arsenic concentration, arsenic forms, pH, chemical compositions of the materials used for adsorption and coagulation, particle size distribution and treatment time on quality of treated water. The experimental results obtained in the study illustrated that both adsorption and coagulation can be used to effectively reduce the concentrations of either arsenic (V) or arsenic (III) from the contaminated water. Coagulation of arsenic with a magnesium-based material developed in this study can be very effective to remove arsenic, especially arsenic (V), from contaminated water with a concentration of 10 ppm to an undetectable level of 0.002 ppm by ICP analyses. Compared to arsenic (III), arsenic (V) is easier to be removed. The materials used for adsorption and coagulation in this study can remove arsenic (V) up to 9 mg/g and 6 mg/g, and arsenic (III) up to 4 mg/g and 3 mg/g, respectively, depending on test conditions and compositions of the materials being used. The control of pH during treatment can be a challenging technical issue for developing both adsorbent and coagulant. Keywords: Water Treatment

  8. Microwave thawing apparatus and method

    DOEpatents

    Fathi, Zakaryae; Lauf, Robert J.; McMillan, April D.

    2004-06-01

    An apparatus for thawing a frozen material includes: a microwave energy source; a microwave applicator which defines a cavity for applying microwave energy from the microwave source to a material to be thawed; and a shielded region which is shielded from the microwave source, the shielded region in fluid communication with the cavity so that thawed material may flow from the cavity into the shielded region.

  9. [Role of tissue factor in atherothrombosis].

    PubMed

    Grybauskas, Pranas

    2003-01-01

    Tissue factor is a key enzyme in coagulation process. It is primary known as a cofactor for factor VIIa-mediated triggering of blood coagulation, which proceeds in a cascade of extracellular reactions. Tissue factor forms a catalytic complex with VIIa and intitiates coagulation by activating factor IX and X, ultimately resulting in thrombin formation. Being a transmembranic glycoprotein it takes a signalling information to another cell activity after endothelium or other tissue damage. Tissue factor plays a pivotal role in blood clotting physiology and pathology especialy in atherothrombosis. Thrombogenic tissue factor on cell-derived microparticles is present in the circulating blood of patients with acute coronary syndromes. Tissue factor is found in adventitia of blood vessels and the lipid core of atherosclerotic plaques (but not in vascular cells contacting directly with blood). Although the molecular mechanisms responsible for these phenomena remain unclear, it is thought that they are brought about by the action of intracellular signaling, resulting in gene transcription and subsequent protein synthesis. By expressing on monocyte or macrofage cell membrane surface it is involved in proinflammatory action and plaque destabilisation. This shifted the emphasis to investigations of what happened on the cell surface, and later to the cell biology of tissue factor and its inducibility in monocytes/macrophages and endothelial cells. Recent studies have suggested that tissue factor also plays non-hemostatic roles in blood vessel development, tumor angiogenesis and metastasis, inflamation. Tissue factor upregulates a number of genes involved in regulation of growth, transcription, and cellular motility, as well as cytokines, makes it possible to suggest a link between the formation of the tissue factor / VIIa complex and the cellular processes. Regulation of tissue factor activity by natural tissue factor pathway inhibitor (synthesized by vascular endothelial cells

  10. Microwave coupler and method

    SciTech Connect

    Holcombe, Cressie E.

    1985-01-01

    The present invention is directed to a microwave coupler for enhancing the heating or metallurgical treatment of materials within a cold-wall, rapidly heated cavity as provided by a microwave furnace. The coupling material of the present invention is an alpha-rhombohedral-boron-derivative-structure material such as boron carbide or boron silicide which can be appropriately positioned as a susceptor within the furnace to heat other material or be in powder particulate form so that composites and structures of boron carbide such as cutting tools, grinding wheels and the like can be rapidly and efficiently formed within microwave furnaces.

  11. Monolithic microwave integrated circuits

    NASA Astrophysics Data System (ADS)

    Pucel, R. A.

    Monolithic microwave integrated circuits (MMICs), a new microwave technology which is expected to exert a profound influence on microwave circuit designs for future military systems as well as for the commercial and consumer markets, is discussed. The book contains an historical discussion followed by a comprehensive review presenting the current status in the field. The general topics of the volume are: design considerations, materials and processing considerations, monolithic circuit applications, and CAD, measurement, and packaging techniques. All phases of MMIC technology are covered, from design to testing.

  12. Microwave coupler and method

    DOEpatents

    Holcombe, C.E.

    1984-11-29

    The present invention is directed to a microwave coupler for enhancing the heating or metallurgical treatment of materials within a cold-wall, rapidly heated cavity as provided by a microwave furnace. The coupling material of the present invention is an alpha-rhombohedral-boron-derivative-structure material such as boron carbide or boron silicide which can be appropriately positioned as a susceptor within the furnace to heat other material or be in powder particulate form so that composites and structures of boron carbide such as cutting tools, grinding wheels and the like can be rapidly and efficiently formed within microwave furnaces.

  13. Microwave vision for robots

    NASA Technical Reports Server (NTRS)

    Lewandowski, Leon; Struckman, Keith

    1994-01-01

    Microwave Vision (MV), a concept originally developed in 1985, could play a significant role in the solution to robotic vision problems. Originally our Microwave Vision concept was based on a pattern matching approach employing computer based stored replica correlation processing. Artificial Neural Network (ANN) processor technology offers an attractive alternative to the correlation processing approach, namely the ability to learn and to adapt to changing environments. This paper describes the Microwave Vision concept, some initial ANN-MV experiments, and the design of an ANN-MV system that has led to a second patent disclosure in the robotic vision field.

  14. Effect of rivaroxaban on blood coagulation using the viscoelastic coagulation test ROTEM™.

    PubMed

    Casutt, M; Konrad, C; Schuepfer, G

    2012-11-01

    This study investigated the influence of the oral direct inhibitor of factor Xa rivaroxaban on blood coagulation measured by rotation thrombelastometry ROTEM™. Blood was obtained from 11 healthy male volunteers before and 2.5 h after oral administration of 10 mg rivaroxaban. In addition to standard coagulation tests clot formation was measured by ROTEM™ analyzing extrinsic (Extem) and intrinsic thrombelastometry (Intem). Significant differences to the baseline values were found in the Extem clotting time (Extem-CT, 58 ± 9 s and 87 ± 17 s, p < 0.01), Intem-CT (194 ± 26 s and 239 ± 43 s; p = 0.02), prothrombin time (PT, 86 ± 9% and 67 ± 7%; p < 0.01) and activated partial thromboplastin time (aPTT, 28 ± 1 s and 35 ± 2 s; p < 0.01). There was a low correlation between Extem-CT and PT as well as between Intem-CT and aPTT before and after rivaroxaban intake. The receiver operating characteristic curve (ROC) analysis determined aPTT to be the most appropriate parameter for the prediction of rivaroxaban-induced anticoagulation, Intem-CT and Extem-CT proved to be moderate tests and PT had no significance in the prediction of rivaroxaban-induced anticoagulation. Of utmost clinical importance was the fact that rivaroxaban treated patients could still show normal ROTEM™ values. Thus, ROTEM™ cannot be a suitable test method to exclude inhibition of blood coagulation by rivaroxaban.

  15. Coagulation-flocculation for lignin removal from wastewater - a review.

    PubMed

    Nawaz, Arfa; Ahmed, Zaki; Shahbaz, Ali; Khan, Zahra; Javed, Mohsin

    2014-01-01

    Industrial discharge has tremendously increased inorganic pollutants in water bodies all over the world. Paper and pulp effluent is included in one of the most pollution generating discharges containing complex chemical compounds such as lignin. For clean and healthy water resources, the recovery of lignin from wastewater from the paper and pulp industry is of high importance. Available chemical and biological technologies for removal of lignin have certain drawbacks. Coagulation and flocculation is not only the economic but also the effective method for removal of lignin. The present review highlights available coagulants employed for removal of lignin from paper and pulp wastewater. Each coagulant is pH dependent and shows varied results with change in effluent characteristics. The hydrolysis products of aluminium-based coagulants, iron-based coagulants and copper sulphate have positive charges. These positive charges promote formation of flocs through charged neutralisation or sweep flocculation. In the case of titanium-based coagulants, hydrolysis product is negatively charged and mode is heterocoagulation. Ninety percent recovery of lignin is achieved by using a mixture of oxotitanium sulphate and aluminium sulphate and 80% with aluminium sulphate. Virtually complete recovery of lignin is observed with oxotitanium sulphate.

  16. Does whole blood coagulation analysis reflect developmental haemostasis?

    PubMed

    Ravn, Hanne Berg; Andreasen, Jo Bnding; Hvas, Anne-Mette

    2016-07-27

    Developmental haemostasis has been well documented over the last 3 decades and age-dependent reference ranges have been reported for a number of plasmatic coagulation parameters. With the increasing use of whole blood point-of-care tests like rotational thromboelastometry (ROTEM) and platelet function tests, an evaluation of age-dependent changes is warranted for these tests as well. We obtained blood samples from 149 children, aged 1 day to 5.9 years, and analysed conventional plasmatic coagulation tests, including activated partial prothrombin time, prothrombin time, and fibrinogen (functional). Whole blood samples were analysed using ROTEM to assess overall coagulation capacity and Multiplate analyzer to evaluate platelet aggregation. Age-dependent changes were analysed for all variables. We found age-dependent differences in all conventional coagulation tests (all P values < 0.05), but there was no sign of developmental changes in whole blood coagulation assessment when applying ROTEM, apart from clotting time in the EXTEM assay (P < 0.03). Despite marked differences in mean platelet aggregation between age groups, data did not reach statistical significance. Citrate-anticoagulated blood showed significantly reduced platelet aggregation compared with blood anticoagulated with heparin or hirudin (all P values < 0.003). We confirmed previous developmental changes in conventional plasmatic coagulation test. However, these age-dependent changes were not displayed in whole blood monitoring using ROTEM or Multiplate analyzer. Type of anticoagulant had a significant influence on platelet aggregation across all age groups.

  17. Treatment of paper and pulp mill effluent by coagulation.

    PubMed

    Chaudhari, Parmesh Kumar; Majumdar, Bidyut; Choudhary, Rumi; Yadav, Deepak Kumar; Chand, Shri

    2010-04-01

    Pulp and paper mill effluent is highly polluting and is a subject of great environmental concern. In the present research we studied the removal of chemical oxygen demand (COD) and colour from paper mill effluent, using the coagulation process. A batch coagulation study was conducted using various coagulants such as aluminium chloride (AlCl3), polyaluminium chloride (PAC) and copper sulphate (CuSO4 x 5H20). The initial pH of the effluent had a tremendous effect on the COD and colour removal. The PAC reduced COD by 83% and reduced colour by 92% at an optimum pH of 5.0 and a coagulant dose of 8 mL L(-1). With AlCl3, at an optimum pH of 4.0 and a coagulant dose of 5 g L(-1), 72% COD removal and 84% colour removal were observed. At an optimum pH of 6.0 and a mass loading of 5 g L(-1), 76% COD reduction and 78% colour reduction were obtained with copper sulphate. It was also observed that, after addition of coagulant, the pH of the effluent decreased. The decrease in the pH was highest with AlCl3, followed by PAC and then CuSO4 x 5H20.

  18. Coagulation-flocculation in leachate treatment using modified micro sand

    NASA Astrophysics Data System (ADS)

    Thaldiri, Nur Hanani; Halim, Azhar Abdul

    2013-11-01

    Sanitary landfill leachate is considered as highly polluted wastewater, without any treatment, discharging into water system will cause underground water and surface water pollutions. This study was to investigate the treatability of the semi-aerobic landfill leachate via coagulation-flocculation using poly-aluminum chloride (PAC), cationic polymer, and modified micro sand. Leachate was collected from Pulau Burung Sanitary Landfill (PBSL) located in Penang, Malaysia. Coagulation-flocculation was performed by using jar test equipment and the effect of pH, dose of coagulant and dose of polymer toward removal of chemical oxygen demand (COD), color and suspended solid (SS) were examined. Micro sand was also used in this study to compare settling time of coagulation-flocculation process. The optimum pH, dose of coagulant (PAC) and dose of polymer (cationic) achieved were 7.0, 1000 mg/L and 8 mg/L, respectively. The dose of micro sand used for the settling time process was 300 mg/L. Results showed that 52.66% removal of COD, 97.16% removal of SS and 96.44% removal of color were achieved under optimum condition. The settling times for the settling down of the sludge or particles that formed during coagulation-flocculation process were 1 min with modified sand, 20 min with raw micro sand and 45 min without micro sand.

  19. Method of Constructing a Microwave Antenna

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James (Inventor); Ngo, Phong (Inventor)

    2003-01-01

    A method, simulation, and apparatus are provided that are highly suitable for treatment of benign prostatic hyperplasia (BPH). A catheter is disclosed that includes a small diameter disk loaded monopole antenna surrounded by fusion material having a high heat of fusion and a melting point preferably at or near body temperature. Microwaves from the antenna heat prostatic tissue to promote necrosing of the prostatic tissue that relieves the pressure of the prostatic tissue against the urethra as the body reabsorbs the necrosed or dead tissue. The fusion material keeps the urethra cool by means of the heat of fusion of the fusion material. This prevents damage to the urethra while the prostatic tissue is necrosed. A computer simulation is provided that can be used to predict the resulting temperature profile produced in the prostatic tissue. By changing the various control features of the catheter and method of applying microwave energy a temperature profile can be predicted and produced that is similar to the temperature profile desired for the particular patient.

  20. Method of constructing a microwave antenna

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James (Inventor); Ngo, Phong (Inventor)

    2003-01-01

    A method, simulation, and apparatus are provided that are highly suitable for treatment of benign prostatic hyperplasia (BPH). A catheter is disclosed that includes a small diameter disk loaded monopole antenna surrounded by fusion material having a high heat of fusion and a melting point preferably at or near body temperature. Microwaves from the antenna heat prostatic tissue to promote necrosing of the prostatic tissue that relieves the pressure of the prostatic tissue against the urethra as the body reabsorbs the necrosed or dead tissue. The fusion material keeps the urethra cool by means of the heat of fusion of the fusion material. This prevents damage to the urethra while the prostatic tissue is necrosed. A computer simulation is provided that can be used to predict the resulting temperature profile produced in the prostatic tissue. By changing the various control features of the catheter and method of applying microwave energy a temperature profile can be predicted and produced that is similar to the temperature profile desired for the particular patient.

  1. Oxidation inhibits iron-induced blood coagulation.

    PubMed

    Pretorius, Etheresia; Bester, Janette; Vermeulen, Natasha; Lipinski, Boguslaw

    2013-01-01

    Blood coagulation under physiological conditions is activated by thrombin, which converts soluble plasma fibrinogen (FBG) into an insoluble clot. The structure of the enzymatically-generated clot is very characteristic being composed of thick fibrin fibers susceptible to the fibrinolytic degradation. However, in chronic degenerative diseases, such as atherosclerosis, diabetes mellitus, cancer, and neurological disorders, fibrin clots are very different forming dense matted deposits (DMD) that are not effectively removed and thus create a condition known as thrombosis. We have recently shown that trivalent iron (ferric ions) generates hydroxyl radicals, which subsequently convert FBG into abnormal fibrin clots in the form of DMDs. A characteristic feature of DMDs is their remarkable and permanent resistance to the enzymatic degradation. Therefore, in order to prevent thrombotic incidences in the degenerative diseases it is essential to inhibit the iron-induced generation of hydroxyl radicals. This can be achieved by the pretreatment with a direct free radical scavenger (e.g. salicylate), and as shown in this paper by the treatment with oxidizing agents such as hydrogen peroxide, methylene blue, and sodium selenite. Although the actual mechanism of this phenomenon is not yet known, it is possible that hydroxyl radicals are neutralized by their conversion to the molecular oxygen and water, thus inhibiting the formation of dense matted fibrin deposits in human blood.

  2. Planetesimal formation by sweep-up coagulation

    NASA Astrophysics Data System (ADS)

    Windmark, Fredrik; Birnstiel, Til; Ormel, Chris W.; Dullemond, Cornelis P.

    2013-07-01

    The formation of planetesimals is often accredited to collisional sticking of dust grains in the protoplanetary disk. The exact process is however unknown, as collisions between larger aggregates tend to lead to fragmentation or bouncing rather than sticking. These growth barriers tend to halt the dust growth already at millimeters or centimeters in size, which is far below the kilometer-sizes that are needed for gravity to aid in the accretion. To study how far dust coagulation can proceed, we have developed a new collision model based on the latest laboratory experiments, and have used it together with a dust-size evolution code capable of resolving all grain interactions in the protoplanetary disk. We find that for the general dust population, bouncing and fragmenting collisions prevent the growth above millimeter-sizes. However, a small number of lucky particles can grow larger than the rest by only interacting at low, sticky velocities. As they grow, they become increasingly resilient to fragmentation caused by the small grains. In this way, two populations are formed: One which remains small due to the collisional barriers, and one that continues to grow by sweeping up the smaller grains around them.

  3. Analysis of changes in MR properties of tissues after heat treatment.

    PubMed

    Graham, S J; Stanisz, G J; Kecojevic, A; Bronskill, M J; Henkelman, R M

    1999-12-01

    To characterize changes in the MR parameters of tissues due to thermal coagulation, a series of T(1), T(2), diffusion, and magnetization transfer measurements were performed on a variety of ex vivo tissues: murine slow twitch skeletal muscle, murine cardiac muscle, murine cerebral hemisphere, bovine white matter, murine liver tissue, bovine retroperitoneal adipose tissue, hen egg white, human prostate and human blood. Standardized heat treatments were performed for each tissue type, over the temperature range from 37 degrees C to 90 degrees C. For all tissues, changes in each MR measurement resulting from thermal coagulation were observed above a threshold temperature of approximately 60 degrees C. These changes are explained based on biophysical knowledge of thermal damage mechanisms and the MR properties of normal tissues, and are particularly relevant for interpreting the changes in image contrast that are observed when MRI is used to guide and monitor thermal coagulation therapy procedures. Magn Reson Med 42:1061-1071, 1999.

  4. 1.06-μm Nd:YAG laser coagulation tonsillectomy: an animal study

    NASA Astrophysics Data System (ADS)

    Wang, Zhi; Pankratov, Michail M.; Volk, Mark S.; Perrault, Donald F., Jr.; Shapshay, Stanley M.

    1995-05-01

    Tonsillectomy is one of the most frequently performed surgeries which is not free from post- operative morbidity. We have developed a non contact photocoagulation technique using 1.06 micrometers Nd:YAG laser and tested its safety and efficacy in an animal model. Eight animals were divided into the laser coagulation group (6 animals) and the laser excision group (2 animals). Tonsils of the laser coagulation animals were irradiated with 8 - 10 W of laser power for 5 - 6 min in a slow painting-like motion over the surface of a tonsil until slight blanching of mucosa was noticed. Tonsils of the laser excision group were resected with 25 - 30 W of 1.06 micrometers Nd:YAG laser power through a contact fiber. The animals were examined endoscopically at 1.5 hrs and at 2, 5, 12, 30, and 42 days post treatment. Atrophic process was followed until total disappearance of tonsillar tissue was observed. The animals were sacrificed at various time intervals and the tonsillar specimens were collected for gross and histological examination. The thermal damage to mucosa and adjacent tissues was minimal which we attribute to a low laser power and cooling from preoperative injection of saline into subcapsular space. The potential advantages of this technique include intact mucosa with no intra- or post-operative bleeding, less pain, and avoidance of general anesthesia. These advantages may enable this surgery to become an in-the-office procedure.

  5. Microwave fluid flow meter

    DOEpatents

    Billeter, Thomas R.; Philipp, Lee D.; Schemmel, Richard R.

    1976-01-01

    A microwave fluid flow meter is described utilizing two spaced microwave sensors positioned along a fluid flow path. Each sensor includes a microwave cavity having a frequency of resonance dependent upon the static pressure of the fluid at the sensor locations. The resonant response of each cavity with respect to a variation in pressure of the monitored fluid is represented by a corresponding electrical output which can be calibrated into a direct pressure reading. The pressure drop between sensor locations is then correlated as a measure of fluid velocity. In the preferred embodiment the individual sensor cavities are strategically positioned outside the path of fluid flow and are designed to resonate in two distinct frequency modes yielding a measure of temperature as well as pressure. The temperature response can then be used in correcting for pressure responses of the microwave cavity encountered due to temperature fluctuations.

  6. Emitron: microwave diode

    DOEpatents

    Craig, G.D.; Pettibone, J.S.; Drobot, A.T.

    1982-05-06

    The invention comprises a new class of device, driven by electron or other charged particle flow, for producing coherent microwaves by utilizing the interaction of electromagnetic waves with electron flow in diodes not requiring an external magnetic field. Anode and cathode surfaces are electrically charged with respect to one another by electron flow, for example caused by a Marx bank voltage source or by other charged particle flow, for example by a high energy charged particle beam. This produces an electric field which stimulates an emitted electron beam to flow in the anode-cathode region. The emitted electrons are accelerated by the electric field and coherent microwaves are produced by the three dimensional spatial and temporal interaction of the accelerated electrons with geometrically allowed microwave modes which results in the bunching of the electrons and the pumping of at least one dominant microwave mode.

  7. Microwave Oven Observations.

    ERIC Educational Resources Information Center

    Sumrall, William J.; Richardson, Denise; Yan, Yuan

    1998-01-01

    Explains a series of laboratory activities which employ a microwave oven to help students understand word problems that relate to states of matter, collect data, and calculate and compare electrical costs to heat energy costs. (DDR)

  8. Influence of NaCl Concentrations on Coagulation, Temperature, and Electrical Conductivity Using a Perfusion Radiofrequency Ablation System: An Ex Vivo Experimental Study

    SciTech Connect

    Aube, Christophe Schmidt, Diethard; Brieger, Jens; Schenk, Martin; Kroeber, Stefan; Vielle, Bruno; Claussen, Claus D.; Goldberg, S. Nahum; Pereira, Philippe L.

    2007-02-15

    Purpose. To determine, by means of an ex vivo study, the effect of different NaCl concentrations on the extent of coagulation obtained during radiofrequency (RF) ablation performed using a digitally controlled perfusion device. Method. Twenty-eight RF ablations were performed with 40 W for 10 min using continuous NaCl infusion in fresh excised bovine liver. For perfusion, NaCl concentrations ranging from 0 (demineralized water) to 25% were used. Temperature, the amount of energy, and the dimensions of thermal-induced white coagulation were assessed for each ablation. These parameters were compared using the nonparametric Mann-Whitney test. Correlations were calculated according to the Spearman test. Results. RF ablation performed with 0.9% to 25% concentrations of NaCl produced a mean volume of coagulation of 30.7 {+-} 3.8 cm{sup 3}, with a mean short-axis diameter of 3.6 {+-} 0.2 cm. The mean amount of energy was 21,895 {+-} 1,674 W and the mean temperature was 85.4 {+-} 12.8 deg. C. Volume of coagulation, short-axis diameter, and amount of energy did not differ significantly among NaCl concentrations (p > 0.5). A correlation was found between the NaCl concentration and the short-axis diameter of coagulation (r = 0.64) and between the NaCl concentration and the mean temperature (r = 0.67), but not between the NaCl concentration and volume of coagulation. Conclusion. In an ex vivo model, continuous perfusion with high NaCl concentrations does not significantly improve the volume of thermal-induced coagulation. This may be because the use of a low-power generator cannot sufficiently exploit the potential advantage of better tissue conductivity provided by NaCl perfusion.

  9. Electromagnetic measurement and modeling techniques for microwave ablation probes.

    PubMed

    Brannan, Joseph D

    2009-01-01

    Broadband scattering parameter measurement of a commercially available microwave ablation probe over the course of a 10 minute 45 Watt ablation cycle within ex-vivo bovine liver tissue is performed. Measurement results are compared to finite difference time domain simulation of the probe in non-ablated and fully ablated tissue geometries. Measurement and simulation results agree well from 0-3 GHz demonstrating the accuracy of a multi-compartmental ablation geometry modeling technique. The electromagnetic modeling technique presented in this paper introduces a useful design tool for optimizing microwave ablation probes without the need for multi-physics simulation packages. The relevance of tissue complex permittivity change with temperature to microwave ablation probe performance is discussed.

  10. Comparison of tissue effects in rabbit muscle of surgical dissection devices.

    PubMed

    Bowers, Christian A; Burns, Greg; Salzman, Karen L; McGill, Lawrence D; Macdonald, Joel D

    2014-01-01

    While some energy-based surgical dissection and coagulation modalities may offer excellent cutting and coagulation abilities, the impact on healing may differ among devices. We compared the tissue effects of three of these modalities with those of the standard surgical scalpel in rabbit muscle at 24 h and 14 days after surgery by evaluating radiographic and histological data. Linear incisions were made with each device in the dorsal lumbar musculature of rabbits using monopolar electrocautery in cut mode (MPE-Cut) and coagulation mode (MPE-Coag), a ferromagnetic induction loop (FMI), and a traditional scalpel. Magnetic resonance imaging scans and histological sampling were done at 24 h and 14 days. Subjective cutting and coagulation characteristics for each device were also recorded during surgery. The scalpel and FMI appeared to cause the least tissue damage adjacent to the incisions in rabbit dorsal lumbar musculature. The scalpel showed the best healing, while the FMI and MPE-Cut demonstrated good healing. The MPE-Coag showed the worst tissue healing. The scalpel, FMI, and MPE-Cut all exhibited favorable subjective characteristics during surgery. It appears that the FMI may be a better choice for surgical dissection and coagulation in muscle tissue than the MPE coagulation mode because it shows less tissue damage and offers better tissue healing.

  11. Coagulation of humic waters for diffused pollution control and the influence of coagulant type on DOC fractions removed.

    PubMed

    Heiderscheidt, Elisangela; Leiviskä, Tiina; Kløve, Bjørn

    2016-10-01

    This study examined the suitability of organic coagulants for treatment of typically humic peat extraction runoff water by comparing their performance with that of ferric sulphate (FS). The influence of coagulant type on dissolved organic carbon (DOC) fractions removed was analysed in detail using LC-OCD-OND (size exclusion liquid chromatography coupled with organic carbon and organic nitrogen detection) fractionation techniques. In general, lower coagulant dosage was needed under acidic (pH 4.5) than neutral (pH 6.5) conditions. Chitosan (Chit) and poly (diallyldimethyl) ammonium chloride (pDMAC) required significantly lower dosage (40-55%) than FS for acceptable purification, while a tannin-based coagulant (Tan2) required substantially higher dosage (55-75%) independent of water pH. FS demonstrated the best removal of DOC (<81%) and phosphorus (<93%) followed by pDMAC, while Chit and Tan2 achieved the highest removal of suspended solids (SS) (<58%), with flocs formed by Tan2 presenting the best settling properties. Higher molecular weight (MW) DOC fractions were more efficiently removed by all coagulants, with FS being the most efficient (biopolymers 69% and humic substances 91%), followed by Tan2. FS also displayed satisfactory removal of lower MW fractions (building blocks ∼46% and low MW neutrals 62%). Overall, FS was the best performing coagulant. Nevertheless, the organic polymers demonstrated satisfactory overall performance, achieving purification rates mostly inside the requirements set by Finnish environmental authorities.

  12. Tunable Microwave Transversal Filters.

    DTIC Science & Technology

    1984-05-01

    GOVT ACCESSION NO. 3. RECIPIENT’S CATALOG NUMBER AFOSR-TR. 84-0977 S4. TI TLE (and Subtitle) 5. TYP ?FE&T&PEO OEE U!NABLE MICROWAVE TRANSVERSAL FILTERS...this goal through magnetostatic waves MSW propagating at microwave frequency in magnetically biased, liquid phase epitaxial films of yttrium iron...garnet (YIG) grown on gadolinium gallium garnet (GGG). This technology has a number of advantages; low loss (greater than 30db/usec at xband), tunable by

  13. Microwave emissions from snow

    NASA Technical Reports Server (NTRS)

    Chang, A. T. C.

    1984-01-01

    The radiation emitted from dry and wet snowpack in the microwave region (1 to 100 GHz) is discussed and related to ground observations. Results from theoretical model calculations match the brightness temperatures obtained by truck mounted, airborne and spaceborne microwave sensor systems. Snow wetness and internal layer structure complicate the snow parameter retrieval algorithm. Further understanding of electromagnetic interaction with snowpack may eventually provide a technique to probe the internal snow properties

  14. High power microwave generator

    DOEpatents

    Ekdahl, Carl A.

    1986-01-01

    A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

  15. High power microwave generator

    DOEpatents

    Ekdahl, C.A.

    1983-12-29

    A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

  16. Automatic Microwave Network Analysis.

    DTIC Science & Technology

    A program and procedure are developed for the automatic measurement of microwave networks using a Hewlett-Packard network analyzer and programmable calculator . The program and procedure are used in the measurement of a simple microwave two port network. These measurements are evaluated by comparing with measurements on the same network using other techniques. The programs...in the programmable calculator are listed in Appendix 1. The step by step procedure used is listed in Appendix 2. (Author)

  17. Noninvasive laser coagulation of the canine vas deferens, in vivo

    NASA Astrophysics Data System (ADS)

    Cilip, Christopher M.; Ross, Ashley E.; Jarow, Jonathan P.; Fried, Nathaniel M.

    2010-02-01

    Development of a noninvasive vasectomy technique may eliminate male fear of complications (incision, bleeding, infection, and scrotal pain) and result in a more popular procedure. This study builds upon previously reported ex vivo tissue studies by exploring acute and short-term chronic in vivo canine studies. Isolation of the canine vas was achieved using a conventional vas ring clamp method. No perforation of the scrotal skin was necessary to occlude the vas. Laser radiation with a wavelength of 1075 nm, average power of 11.2 W, 500-ms pulse duration, 0.5 Hz pulse rate, and 3-mm-diameter spot was synchronized with cryogen spray cooling of the scrotal skin surface in a total of 8 dogs (n = 16 vasa) for a treatment time of 60 s. Burst pressure measurements were conducted at Days 0 and 21 (n = 8 vasa each day) to quantify the strength of vas closure. The vas was successfully thermally occluded in 15/16 (94%) procedures with 14/15 (93%) vas recording burst pressures above ejaculation pressure. One vas was not present, and another vas recorded a bursting pressure below ejaculation pressure. The coagulated vas bursting pressure averaged 283 +/- 34 mm Hg at Day 0 and 260 +/- 77 mm Hg at Day 21, significantly higher than reported vas ejaculation pressures of 136 +/- 29 mm Hg. Minor scrotal skin burns were observed during the recovery period. Noninvasive thermal occlusion of the vas is feasible in an in vivo canine model. Elimination of minor skin burns and longer term chronic in vivo canine studies are needed to confirm azospermia after vas occlusion without recanalization.

  18. The electromagnetic-trait imaging computation of traveling wave method in breast tumor microwave sensor system.

    PubMed

    Tao, Zhi-Fu; Han, Zhong-Ling; Yao, Meng

    2011-01-01

    Using the difference of dielectric constant between malignant tumor tissue and normal breast tissue, breast tumor microwave sensor system (BRATUMASS) determines the detected target of imaging electromagnetic trait by analyzing the properties of target tissue back wave obtained after near-field microwave radicalization (conelrad). The key of obtained target properties relationship and reconstructed detected space is to analyze the characteristics of the whole process from microwave transmission to back wave reception. Using traveling wave method, we derive spatial transmission properties and the relationship of the relation detected points distances, and valuate the properties of each unit by statistical valuation theory. This chapter gives the experimental data analysis results.

  19. Hearing of microwave pulses by humans and animals: effects, mechanism, and thresholds.

    PubMed

    Lin, James C; Wang, Zhangwei

    2007-06-01

    The hearing of microwave pulses is a unique exception to the airborne or bone-conducted sound energy normally encountered in human auditory perception. The hearing apparatus commonly responds to airborne or bone-conducted acoustic or sound pressure waves in the audible frequency range. But the hearing of microwave pulses involves electromagnetic waves whose frequency ranges from hundreds of MHz to tens of GHz. Since electromagnetic waves (e.g., light) are seen but not heard, the report of auditory perception of microwave pulses was at once astonishing and intriguing. Moreover, it stood in sharp contrast to the responses associated with continuous-wave microwave radiation. Experimental and theoretical studies have shown that the microwave auditory phenomenon does not arise from an interaction of microwave pulses directly with the auditory nerves or neurons along the auditory neurophysiological pathways of the central nervous system. Instead, the microwave pulse, upon absorption by soft tissues in the head, launches a thermoelastic wave of acoustic pressure that travels by bone conduction to the inner ear. There, it activates the cochlear receptors via the same process involved for normal hearing. Aside from tissue heating, microwave auditory effect is the most widely accepted biological effect of microwave radiation with a known mechanism of interaction: the thermoelastic theory. The phenomenon, mechanism, power requirement, pressure amplitude, and auditory thresholds of microwave hearing are discussed in this paper. A specific emphasis is placed on human exposures to wireless communication fields and magnetic resonance imaging (MRI) coils.

  20. Microwaves and Alzheimer's disease

    PubMed Central

    Zhang, Xia; Huang, Wen-Juan; Chen, Wei-Wei

    2016-01-01

    Alzheimer's diseases (AD) is the most common type of dementia and a neurodegenerative disease that occurs when the nerve cells in the brain die. The cause and treatment of AD remain unknown. However, AD is a disease that affects the brain, an organ that controls behavior. Accordingly, anything that can interact with the brain may affect this organ positively or negatively, thereby protecting or encouraging AD. In this regard, modern life encompasses microwaves for all issues including industrial, communications, medical and domestic tenders, and among all applications, the cell phone wave, which directly exposes the brain, continues to be the most used. Evidence suggests that microwaves may produce various biological effects on the central nervous system (CNS) and many arguments relay the possibility that microwaves may be involved in the pathophysiology of CNS disease, including AD. By contrast, previous studies have reported some beneficial cognitive effects and that microwaves may protect against cognitive impairment in AD. However, although many of the beneficial effects of microwaves are derived from animal models, but can easily be extrapolated to humans, whether microwaves cause AD is an important issue that is to be addressed in the current review. PMID:27698682

  1. Microwaves and Alzheimer's disease.

    PubMed

    Zhang, Xia; Huang, Wen-Juan; Chen, Wei-Wei

    2016-10-01

    Alzheimer's diseases (AD) is the most common type of dementia and a neurodegenerative disease that occurs when the nerve cells in the brain die. The cause and treatment of AD remain unknown. However, AD is a disease that affects the brain, an organ that controls behavior. Accordingly, anything that can interact with the brain may affect this organ positively or negatively, thereby protecting or encouraging AD. In this regard, modern life encompasses microwaves for all issues including industrial, communications, medical and domestic tenders, and among all applications, the cell phone wave, which directly exposes the brain, continues to be the most used. Evidence suggests that microwaves may produce various biological effects on the central nervous system (CNS) and many arguments relay the possibility that microwaves may be involved in the pathophysiology of CNS disease, including AD. By contrast, previous studies have reported some beneficial cognitive effects and that microwaves may protect against cognitive impairment in AD. However, although many of the beneficial effects of microwaves are derived from animal models, but can easily be extrapolated to humans, whether microwaves cause AD is an important issue that is to be addressed in the current review.

  2. Microwave sintering process model.

    PubMed

    Peng, Hu; Tinga, W R; Sundararaj, U; Eadie, R L

    2003-01-01

    In order to simulate and optimize the microwave sintering of a silicon nitride and tungsten carbide/cobalt toolbits process, a microwave sintering process model has been built. A cylindrical sintering furnace was used containing a heat insulating layer, a susceptor layer, and an alumina tube containing the green toolbit parts between parallel, electrically conductive, graphite plates. Dielectric and absorption properties of the silicon nitride green parts, the tungsten carbide/cobalt green parts, and an oxidizable susceptor material were measured using perturbation and waveguide transmission methods. Microwave absorption data were measured over a temperature range from 20 degrees C to 800 degrees C. These data were then used in the microwave process model which assumed plane wave propagation along the radial direction and included the microwave reflection at each interface between the materials and the microwave absorption in the bulk materials. Heat transfer between the components inside the cylindrical sintering furnace was also included in the model. The simulated heating process data for both silicon nitride and tungsten carbide/cobalt samples closely follow the experimental data. By varying the physical parameters of the sintering furnace model, such as the thickness of the susceptor layer, the thickness of the allumina tube wall, the sample load volume and the graphite plate mass, the model data predicts their effects which are helpful in optimizing those parameters in the industrial sintering process.

  3. Disseminated intravascular coagulation or acute coagulopathy of trauma shock early after trauma? An observational study

    PubMed Central

    2011-01-01

    Introduction It is debated whether early trauma-induced coagulopathy (TIC) in severely injured patients reflects disseminated intravascular coagulation (DIC) with a fibrinolytic phenotype, acute coagulopathy of trauma shock (ACoTS) or yet other entities. This study investigated the prevalence of overt DIC and ACoTS in trauma patients and characterized these conditions based on their biomarker profiles. Methods An observational study was carried out at a single Level I Trauma Center. Eighty adult trauma patients (≥18 years) who met criteria for full trauma team activation and had an arterial cannula inserted were included. Blood was sampled a median of 68 minutes (IQR 48 to 88) post-injury. Data on demography, biochemistry, injury severity score (ISS) and mortality were recorded. Plasma/serum was analyzed for biomarkers reflecting tissue/endothelial cell/glycocalyx damage (histone-complexed DNA fragments, Annexin V, thrombomodulin, syndecan-1), coagulation activation/inhibition (prothrombinfragment 1+2, thrombin/antithrombin-complexes, antithrombin, protein C, activated protein C, endothelial protein C receptor, protein S, tissue factor pathway inhibitor, vWF), factor consumption (fibrinogen, FXIII), fibrinolysis (D-dimer, tissue-type plasminogen activator, plasminogen activator inhibitor-1) and inflammation (interleukin (IL)-6, terminal complement complex (sC5b-9)). Comparison of patients stratified according to the presence or absence of overt DIC (International Society of Thrombosis and Hemostasis (ISTH) criteria) or ACoTS (activated partial thromboplastin time (APTT) and/or international normalized ratio (INR) above normal reference). Results No patients had overt DIC whereas 15% had ACoTS. ACoTS patients had higher ISS, transfusion requirements and mortality (all P < 0.01) and a biomarker profile suggestive of enhanced tissue, endothelial cell and glycocalyx damage and consumption coagulopathy with low protein C, antithrombin, fibrinogen and FXIII levels

  4. Characterization and coagulation of a polyaluminum chloride (PAC) coagulant with high Al13 content.

    PubMed

    Gao, Bao-Yu; Chu, Yong-Bao; Yue, Qin-Yan; Wang, Bing-Jian; Wang, Shu-Guang

    2005-07-01

    A polyaluminum chloride (PAC) coagulant was prepared from AlCl3 x 6H2O and Na2CO3. The Al13 species in PAC was separated and purified by the SO4(2-)/Ba2+ deposition-replacement method, and characterized by 27Al-NMR and XRD. From 27Al-NMR spectroscopy, it was found that PAC obtained after separation and purification contained more Al13 (PAC-Al13, for short) than original PAC before separation and purification. In XRD spectra, a strong Al13 signal appeared in the range of 2theta from 5 to 25 degrees. Jar tests were performed to test the coagulation efficiency of AlCl3, PAC and PAC-Al13 in treating synthetic or actual water samples. Compared with PAC and AlCl3, PAC-Al13 gives the best results for turbidity, humic acid and color removal, and achieves the highest charge-neutralizing ability. Under the study conditions, PAC-Al13 gave about 90% humic acid removal and almost 100% reactive blue dye removal when its dosages were 4.0 and 15 mg/L as Al, respectively. The Al13 species has a higher positive charge and is the most effective polymeric Al species in water and wastewater treatment.

  5. Microwave radiation absorption: behavioral effects.

    PubMed

    D'Andrea, J A

    1991-07-01

    The literature contains much evidence that absorption of microwave energy will lead to behavioral changes in man and laboratory animals. The changes include simple perturbations or outright stoppage of ongoing behavior. On one extreme, intense microwave absorption can result in seizures followed by death. On the other extreme, man and animals can hear microwave pulses at very low rates of absorption. Under certain conditions of exposure, animals will avoid microwaves, while under other conditions, they will actively work to obtain warmth produced by microwaves. Some research has shown behavioral effects during chronic exposure to low-level microwaves. The specific absorption rates that produce behavioral effects seem to depend on microwave frequency, but controversy exists over thresholds and mechanism of action. In all cases, however, the behavioral disruptions cease when chronic microwave exposure is terminated. Thermal changes in man and animals during microwave exposure appear to account for all reported behavioral effects.

  6. Interstitial laser coagulation for localized destruction of solid tumors: overview of strategies

    NASA Astrophysics Data System (ADS)

    van Hillegersberg, Richard

    1997-06-01

    Interstitial laser coagulation (ILC) is a new method of producing localized tissue destruction, that may be used to eliminate soli tumors, such as liver metastases, pancreatic carcinomas, brain glioma and benign prostate hyperplasia. In ILC, Nd:YAG laser light is guided through flexible quartz fibers implanted directly into the tumor. Several experimental studies have shown the effectiveness of this therapy. Clinical application is feasible, however success in malignant tumors is limited by: (1) the restricted lesion size produced by a single optical fiber and (2) the lack of reliable on-line monitoring of the laser-induced effects. Research is therefore directed towards the development of multiple fiber application, guided by real time feedback of the laser-tissue interaction.

  7. Instantaneous gelation in Smoluchowski's coagulation equation revisited

    NASA Astrophysics Data System (ADS)

    Ball, Robin C.; Connaughton, Colm; Stein, Thorwald H. M.; Zaboronski, Oleg

    2011-07-01

    We study the solutions of the Smoluchowski coagulation equation with a regularization term which removes clusters from the system when their mass exceeds a specified cutoff size, M. We focus primarily on collision kernels which would exhibit an instantaneous gelation transition in the absence of any regularization. Numerical simulations demonstrate that for such kernels with monodisperse initial data, the regularized gelation time decreases as M increases, consistent with the expectation that the gelation time is zero in the unregularized system. This decrease appears to be a logarithmically slow function of M, indicating that instantaneously gelling kernels may still be justifiable as physical models despite the fact that they are highly singular in the absence of a cutoff. We also study the case when a source of monomers is introduced in the regularized system. In this case a stationary state is reached. We present a complete analytic description of this regularized stationary state for the model kernel, K(m1,m2)=max{m1,m2}ν, which gels instantaneously when M→∞ if ν>1. The stationary cluster size distribution decays as a stretched exponential for small cluster sizes and crosses over to a power law decay with exponent ν for large cluster sizes. The total particle density in the stationary state slowly vanishes as [(ν-1)logM]-1/2 when M→∞. The approach to the stationary state is nontrivial: Oscillations about the stationary state emerge from the interplay between the monomer injection and the cutoff, M, which decay very slowly when M is large. A quantitative analysis of these oscillations is provided for the addition model which describes the situation in which clusters can only grow by absorbing monomers.

  8. Endothelium Preserving Microwave Treatment for Atherosclerosis

    NASA Technical Reports Server (NTRS)

    Carl, James R. (Inventor); Arndt, G. Dickey (Inventor); Fink, Patrick W. (Inventor); Beer, N. Reginald (Inventor); Henry, Phillip D. (Inventor); Pacifico, Antonio (Inventor); Raffoul, George W. (Inventor)

    2000-01-01

    Method and apparatus are provided to treat atherosclerosis wherein the artery is partially closed by dilating the artery while preserving the vital and sensitive endothelial layer thereof Microwave energy having a frequency from 3 GHz to 300 GHz is propagated into the arterial wall to produce a desired temperature profile therein at tissue depths sufficient for thermally necrosing connective tissue and softening fatty and waxy plaque while limiting heating of surrounding tissues including the endothelial laser and/or other healthy tissue, organs, and blood. The heating period for raising the temperature a potentially desired amount, about 20 C., within the atherosclerotic lesion may be less than about one second. In one embodiment of the invention, a radically beveled waveguide antenna is used to deliver microwave energy at frequencies from 25 GHz or 30 GHz to about 300 GHz and is focused towards a particular radial sector of the artery. Because the atherosclerotic lesions are often asymmetrically disposed, directable of focussed heating preserves healthy sectors of the artery and applies energy to the asymmetrically positioned lesion faster than a non-directed beam. A computer simulation predicts isothermic temperature profiles for the given conditions and man be used in selecting power, pulse duration, beam width, and frequency of operation to maximize energy deposition and control heat rise within the atherosclerotic lesion without harming healthy tissues or the sensitive endothelium cells.

  9. Endothelium Preserving Microwave Treatment for Atherosclerosis

    NASA Technical Reports Server (NTRS)

    Carl, James R. (Inventor); Arndt, Dickey (Inventor); Fink, Patrick W. (Inventor); Beer, Reginald (Inventor); Henry, Phillip D. (Inventor); Pacifico, Antonio (Inventor); Raffoul, George W. (Inventor)

    2002-01-01

    Method and apparatus are provided to treat atherosclerosis wherein the artery is partially closed by dilating the artery while preserving the vital and sensitive endothelial layer thereof. Microwave energy having a frequency from 3 GHz to 300 GHz is propagated into the arterial wall to produce a desired temperature profile therein at tissue depths sufficient for thermally necrosing connective tissue and softening fatty and waxy plaque while limiting heating of surrounding tissues including the endothelial layer and/or other healthy tissue, organs, and blood. The heating period for raising the temperature a potentially desired amount, about 20 C. within the atherosclerotic lesion may be less than about one second. In one embodiment of the invention, a radically beveled waveguide antenna is used to deliver microwave energy at frequencies from 25 GHz or 30 GHz to about 300 GHz and is focused towards a particular radial sector of the artery. Because the atherosclerotic lesions are often asymmetrically disposed, directable or focussed heating preserves healthy sectors or the artery and applies energy to the asymmetrically positioned lesion faster than a non-directed bean. A computer simulation predicts isothermic temperature profiles for the given conditions and may be used in selecting power, pulse duration, beam width, and frequency of operation to maximize energy deposition and control heat rise within the atherosclerotic lesion without harming healthy tissues or the sensitive endothelium cells.

  10. Endothelium Preserving Microwave Treatment for Atherosclerosis

    NASA Technical Reports Server (NTRS)

    Carl, James R. (Inventor); Arndt, G. Dickey (Inventor); Fink, Patrick W. (Inventor); Beer, N. Reginald (Inventor); Henry, Phillip D. (Inventor); Pacifico, Antonio (Inventor); Raffoul, George W. (Inventor)

    2001-01-01

    Method and apparatus are provided to treat atherosclerosis wherein the artery is partially closed by dilating the artery while preserving the vital and sensitive endothelial layer thereof. Microwave energy having a frequency from 3 GHz to 300 GHz is propagated into the arterial wall to produce a desired temperature profile therein at tissue depths sufficient for thermally necrosing connective tissue and softening fatty and waxy plaque while limiting heating of surrounding tissues including the endothelial layer and/or other healthy tissue, organs, and blood. The heating period for raising the temperature a potentially desired amount, about 20 C. within the atherosclerotic lesion may be less than about one second. In one embodiment of the invention, a radically beveled waveguide antenna is used to deliver microwave energy at frequencies from 25 GHz or 30 GHz to about 300 GHz and is focused towards a particular radial sector of the artery. Because the atherosclerotic lesions are often asymmetrically disposed directable or focussed heating preserves healthy sectors of the artery and applies energy to the asymmetrically positioned lesion faster than a non-directed beam. A computer simulation predicts isothermic temperature profiles for the given conditions and may be used in selecting power, pulse duration, beam width, and frequency of operation to maximize energy deposition and control heat rise within the atherosclerotic lesion without harming healthy tissues or the sensitive endothelium cells.

  11. Endothelium Preserving Microwave Treatment for Atherosclerois

    NASA Technical Reports Server (NTRS)

    Carl, James R. (Inventor); Arndt, G. Dickey (Inventor); Fink, Patrick W. (Inventor); Beer, N. Reginald (Inventor); Henry, Phillip D. (Inventor); Pacifico, Antonio (Inventor); Raffoul, George W. (Inventor)

    2001-01-01

    Method and apparatus are provided to treat atherosclerosis wherein the artery is partially closed by dilating the artery while preserving the vital and sensitive endothelial layer thereof. Microwave energy having a frequency from 3 GHz to 300 GHz is propagated into the arterial wall to produce a desired temperature profile therein at tissue depths sufficient for thermally necrosing connective tissue and softening fatty and waxy plaque while limiting heating of surrounding tissues including the endothelial layer and/or other healthy tissue, organs, and blood. The heating period for raising the temperature a potentially desired amount about 20 C, with the atherosclerotic lesion may be less than about one second. In one embodiment of the invention, a radically beveled waveguide antenna is used to deliver microwave energy at frequencies from 25 GHz or 30 GHz to about 300 GHz and is focused towards a particular radical sector of the artery. Because the atherosclerotic lesions are often asymmetrically disposed, directable or focussed heating preserves healthy sectors of the artery and applies energy to the asymmetrically positioned lesion faster than a non-directed beam. A computer simulation predicts isothermic temperature profiles for the given conditions and may be used in selecting power, pulse duration, beam width, and frequency of operation to maximize energy deposition and control heat rise within the atherosclerotic lesion without harming healthy tissues or the sensitive endothelium cells.

  12. Microwave Radiothermometry (9GHz) Applied To Breast Cancer

    NASA Astrophysics Data System (ADS)

    Gautherie, M.; Mamouni, A.; Samsel, M.; Guerquin-Kern, J. L.; Leroy, Y.; Gros, Ch.

    1980-05-01

    Radiothermometric investigations have been carried out on breast cancer patients and on patients with tumors of various localizations and histologic types (liver,thyrold,...) (55 cases), by means of a high sensitivity hyperfrequency radiometer operating at 9GHz.The findings were analyzed as follow: (a) comparison between microwave thermal mapping and infrared thermography; (b) correlations with various morphologic and thermal parameters (depth and size oftumor thermal conductivity, vascularization and x-ray structures of tissues). Microwave radiometry seems to be able to provide significant information on meta-bolism and thermal conditions of subcutaneous tumor tissue, especially under those clinical situations where infrared thermography does not work.

  13. Design of a microwave calorimeter for the microwave tokamak experiment

    SciTech Connect

    Marinak, M. )

    1988-10-07

    The initial design of a microwave calorimeter for the Microwave Tokamak Experiment is presented. The design is optimized to measure the refraction and absorption of millimeter rf microwaves as they traverse the toroidal plasma of the Alcator C tokamak. Techniques utilized can be adapted for use in measuring high intensity pulsed output from a microwave device in an environment of ultra high vacuum, intense fields of ionizing and non-ionizing radiation and intense magnetic fields. 16 refs.

  14. Coagulation tests show significant differences in patients with breast cancer.

    PubMed

    Tas, Faruk; Kilic, Leyla; Duranyildiz, Derya

    2014-06-01

    Activated coagulation and fibrinolytic system in cancer patients is associated with tumor stroma formation and metastasis in different cancer types. The aim of this study is to explore the correlation of blood coagulation assays for various clinicopathologic factors in breast cancer patients. A total of 123 female breast cancer patients were enrolled into the study. All the patients were treatment naïve. Pretreatment blood coagulation tests including PT, APTT, PTA, INR, D-dimer, fibrinogen levels, and platelet counts were evaluated. Median age of diagnosis was 51 years old (range 26-82). Twenty-two percent of the group consisted of metastatic breast cancer patients. The plasma level of all coagulation tests revealed statistically significant difference between patient and control group except for PT (p<0.001 for all variables except for PT; p=0.08). Elderly age (>50 years) was associated with higher D-dimer levels (p=0.003). Metastatic patients exhibited significantly higher D-dimer values when compared with early breast cancer patients (p=0.049). Advanced tumor stage (T3 and T4) was associated with higher INR (p=0.05) and lower PTA (p=0.025). In conclusion, coagulation tests show significant differences in patients with breast cancer.

  15. Splenic hematoma in acute pancreatitis. Role of coagulation disorders.

    PubMed

    Clavé, P; Guillaumes, S; Blanco, I; Martínez de Hurtado, J; Esquius, J; Marruecos, L; Fontcuberta, J; Pérez, C; Farré, A; Lluís, F

    1992-08-01

    Splenic hematomas are infrequent complications of acute pancreatitis. In some cases, local factors that may play a role in the pathogenesis of the hematoma (thrombosis of the splenic artery or veins, intrasplenic pseudocysts, perisplenic adhesions, enzymatic digestion) are found. In the absence of local factors, the etiology of splenic hemorrhage remains unknown. We report two cases of splenic hematoma occurring during an acute necro-hemorrhagic pancreatitis associated with renal failure that required renal replacement therapy (hemodialysis and continuous arteriovenous hemodialysis). In both cases, more than half of splenic parenchyma was affected by multiple infarctions. No local factors responsible for the splenic abnormalities were detected in either case. Thrombosis of the splenic arterial microcirculation and a coagulation disorder consistent with disseminated intravascular coagulation was detected in one patient. In the second patient, coagulation disorders secondary to either liver disease, pancreatitis and its septic complications, or extracorporeal circuit heparinization for renal replacement therapy were present. Coagulation disorders should be considered whenever a splenic hematoma is found in a patient with acute pancreatitis. Disseminated intravascular coagulation may be the etiology of a splenic hematoma in acute pancreatitis.

  16. Clay-catalyzed reactions of coagulant polymers during water chlorination

    USGS Publications Warehouse

    Lee, J.-F.; Liao, P.-M.; Lee, C.-K.; Chao, H.-P.; Peng, C.-L.; Chiou, C.T.

    2004-01-01

    The influence of suspended clay/solid particles on organic-coagulant reactions during water chlorination was investigated by analyses of total product formation potential (TPFP) and disinfection by-product (DBP) distribution as a function of exchanged clay cation, coagulant organic polymer, and reaction time. Montmorillonite clays appeared to act as a catalytic center where the reaction between adsorbed polymer and disinfectant (chlorine) was mediated closely by the exchanged clay cation. The transition-metal cations in clays catalyzed more effectively than other cations the reactions between a coagulant polymer and chlorine, forming a large number of volatile DBPs. The relative catalytic effects of clays/solids followed the order Ti-Mont > Fe-Mont > Cu-Mont > Mn-Mont > Ca-Mont > Na-Mont > quartz > talc. The effects of coagulant polymers on TPFP follow the order nonionic polymer > anionic polymer > cationic polymer. The catalytic role of the clay cation was further confirmed by the observed inhibition in DBP formation when strong chelating agents (o-phenanthroline and ethylenediamine) were added to the clay suspension. Moreover, in the presence of clays, total DBPs increased appreciably when either the reaction time or the amount of the added clay or coagulant polymer increased. For volatile DBPs, the formation of halogenated methanes was usually time-dependent, with chloroform and dichloromethane showing the greatest dependence. ?? 2003 Elsevier Inc. All rights reserved.

  17. Blood coagulation and propagation of autowaves in flow.

    PubMed

    Ermakova, Elena A; Panteleev, Mikhail A; Shnol, Emmanuil E

    2005-01-01

    This study analyses the effect of flow and boundary reactions on spatial propagation of waves of blood coagulation. A simple model of coagulation in plasma consisting of three differential reaction-diffusion equations was used for numerical simulations. The vessel was simulated as a two-dimensional channel of constant width, and the anticoagulant influence of thrombomodulin present on the undamaged vessel wall was taken into account. The results of the simulations showed that this inhibition could stop the coagulation process in the absence of flow in narrow channels. For the used mathematical model of coagulation this was the case if the width was below 0.2 mm. In wider vessels, the process could be stopped by the rapid blood flow. The required flow rate increased with the increase of the damage region size. For example, in a 0.5-mm wide channel with 1-mm long damage region, the propagation of coagulation may be terminated at the flow rate of more than 20 mm/min.

  18. A mini review of preoxidation to improve coagulation.

    PubMed

    Xie, Pengchao; Chen, Yiqun; Ma, Jun; Zhang, Xiang; Zou, Jing; Wang, Zongping

    2016-07-01

    Preoxidation has attracted people's attention due to its effectiveness in enhancing coagulation. The mechanisms, drawbacks and applications in the improvement of coagulation were summarized in this work. Preoxidation can destroy the organic coating on the surface of particles to change the zeta potential, which is the vital reason for improving coagulation. Co-existing metallic ions, such as calcium, iron and manganese, play important roles in the improvement of coagulation due to the formation of metal-humate complexes or the in situ formed coagulant. However, preoxidation could degrade organic matter from high molecular weight to low molecular weight and damage cell membrane of algae, causing intracellular algal organic matter to release outside and producing hydrophilic functional groups to some extent, which has the potential to deteriorate the water quality. Additionally, disinfection byproduct formation is also affected significantly through changing the characteristics of the organic and inorganic precursors. Based on the recent publications, some future developments of preoxidation process were suggested in this study.

  19. Comparison of Moringa stenopetala seed extract as a clean coagulant with Alum and Moringa stenopetala-Alum hybrid coagulant to remove direct dye from Textile Wastewater.

    PubMed

    Dalvand, Arash; Gholibegloo, Elham; Ganjali, Mohammad Reza; Golchinpoor, Najmeh; Khazaei, Mohammad; Kamani, Hossein; Hosseini, Sara Sadat; Mahvi, Amir Hossein

    2016-08-01

    In this study, the efficiency of Moringa stenopetala seed extract was compared with alum and M. stenopetala-alum hybrid coagulant to remove Direct Red 23 azo dye from textile wastewater. The effects of parameters such as pH, coagulant dose, type of salt used for the extraction of coagulant and initial dye concentration on dye removal efficiency were investigated. Moreover, the existing functional groups on the structure of M. stenopetala coagulant (MSC) were determined by Fourier transform infrared spectroscopy, and the morphology of sludge produced by MSC, alum, and hybrid coagulant was characterized by scanning electron microscopy. Ninhydrin test was also used to determine the quantity of primary amines in the MSC and Moringa oleifera coagulant (MOC). According to the results, with increasing the coagulant dose and decreasing the initial dye concentration, dye removal efficiency has increased. The maximum dye removal of 98.5, 98.2, and 98.3 % were obtained by using 240, 120, and 80 mg/L MSC, alum and hybrid coagulant at pH 7, respectively. The results also showed MSC was much more effective than MOC for dye removal. The volume of sludge produced by MSC was one fourth and half of those produced by alum and hybrid coagulant, respectively. Based on the results, hybrid coagulant was the most efficient coagulant for direct dye removal from colored wastewater.

  20. [Digital noninvasive microwave thermography in the diagnosis of breast disease].

    PubMed

    Fan, K H; Fan, J H; Yao, D D; Jin, W D; Yang, B G; Meng, C X; Qu, D B

    1988-05-01

    Thermography is a noninvasive technic of examination. Liquid-Crystal Thermography and Infrared Thermography have provided great help in the general survey of breast diseases during the past twenty years but not without some limitations. Recently, by applying the microwave technic clinically, progress has been made to measure minute temperature changes in the deeper tissues. Differential diagnosis of breast disease is possible by statistical calculating the temperature difference of the two breasts. A prospective study was done in 96 women who had both X ray mammography and digital noninvasive microwave thermography. 70/96 were proved by pathology. In this group of patients, the accuracy rate was 70.00% for digital microwave thermography, 81.82% for X ray mammography and 95.50% for the two combined. The false positive rates and false negative rates, advantages, disadvantages and the for general survey of breast disease of the digital microwave thermography discussed.

  1. Platelet-localized FXI promotes a vascular coagulation-inflammatory circuit in arterial hypertension.

    PubMed

    Kossmann, Sabine; Lagrange, Jeremy; Jäckel, Sven; Jurk, Kerstin; Ehlken, Moritz; Schönfelder, Tanja; Weihert, Yvonne; Knorr, Maike; Brandt, Moritz; Xia, Ning; Li, Huige; Daiber, Andreas; Oelze, Matthias; Reinhardt, Christoph; Lackner, Karl; Gruber, Andras; Monia, Brett; Karbach, Susanne H; Walter, Ulrich; Ruggeri, Zaverio M; Renné, Thomas; Ruf, Wolfram; Münzel, Thomas; Wenzel, Philip

    2017-02-01

    Multicellular interactions of platelets, leukocytes, and the blood vessel wall support coagulation and precipitate arterial and venous thrombosis. High levels of angiotensin II cause arterial hypertension by a complex vascular inflammatory pathway that requires leukocyte recruitment and reactive oxygen species production and is followed by vascular dysfunction. We delineate a previously undescribed, proinflammatory coagulation-vascular circuit that is a major regulator of vascular tone, blood pressure, and endothelial function. In mice with angiotensin II-induced hypertension, tissue factor was up-regulated, as was thrombin-dependent endothelial cell vascular cellular adhesion molecule 1 expression and integrin αMβ2- and platelet-dependent leukocyte adhesion to arterial vessels. The resulting vascular inflammation and dysfunction was mediated by activation of thrombin-driven factor XI (FXI) feedback, independent of factor XII. The FXI receptor glycoprotein Ibα on platelets was required for this thrombin feedback activation in angiotensin II-infused mice. Inhibition of FXI synthesis with an antisense oligonucleotide was sufficient to prevent thrombin propagation on platelets, vascular leukocyte infiltration, angiotensin II-induced endothelial dysfunction, and arterial hypertension in mice and rats. Antisense oligonucleotide against FXI also reduced the increased blood pressure and attenuated vascular and kidney dysfunction in rats with established arterial hypertension. Further, platelet-localized thrombin generation was amplified in an FXI-dependent manner in patients with uncontrolled arterial hypertension, suggesting that platelet-localized thrombin generation may serve as an inflammatory marker of high blood pressure. Our results outline a coagulation-inflammation circuit that promotes vascular dysfunction, and highlight the possible utility of FXI-targeted anticoagulants in treating hypertension, beyond their application as antithrombotic agents in

  2. MICROWAVE TECHNOLOGY CHEMICAL SYNTHESIS APPLICATIONS

    EPA Science Inventory

    Microwave-accelerated chemical syntheses in various solvents as well as under solvent-free conditions have witnessed an explosive growth. The technique has found widespread application predominantly exploiting the inexpensive unmodified household microwave (MW) ovens although th...

  3. Comparison of coagulation pretreatment of produced water from natural gas well by polyaluminium chloride and polyferric sulphate coagulants.

    PubMed

    Zhai, Jun; Huang, Zejin; Rahaman, Md Hasibur; Li, Yue; Mei, Longyue; Ma, Hongpu; Hu, Xuebin; Xiao, Haiwen; Luo, Zhiyong; Wang, Kunping

    2016-08-19

    This study aimed to optimise coagulation pretreatment of the produced water (PW) collected from a natural gas field. Two coagulants, polyferric sulphate (PFS) and polyaluminium chloride (PACl), were applied separately for the organics, suspended solids (SS), and colour removal. Treatment performance at different coagulant dosages, initial pH values, stirring patterns, and the addition of cationic polyacrylamide (PAM) was investigated in jar tests. The optimal coagulation conditions were dosage of PACl 25 g/L or PFS 20 g/L with that of PAM 30 mg/L, initial pH of 11, and fast mixing of 1.5 min (for PACl) or 2 min (for PFS) at 250 rpm followed by slow mixing of 15 min at 50 rpm for both coagulants. PACl performed better than PFS to remove chemical oxygen demand (COD), total organic carbon (TOC), SS, and colour, and achieved a removal efficiency of 90.1%, 89.4%, 99.0%, and 99.9%, respectively, under the optimal condition; while PFS efficiency was 86.1%, 86.1%, 99.0%, and 98.2%, respectively. However, oil removal was higher in PFS coagulation compared to PACl and showed 98.9% and 95.3%, respectively. Biodegradability, ratio of the biological oxygen demand (five-day) (BOD5)/COD, of the PW after pretreatment increased from 0.08 to 0.32 for PFS and 0.43 for PACl. Zeta potential (Z-potential) analysis at the optimum coagulant dosage of PACl and PFS suggests that charge neutralisation was the predominant mechanism during coagulation. Better efficiency was observed at higher pH. The addition of PAM and starring pattern had a minor influence on the removal performance of both coagulants. The results suggest that PACl or PFS can be applied for the pretreatment of PW, which can provide substantial removal of carbon, oil, and colour, a necessary first step for subsequent main treatment units such as chemical oxidation or biological treatment.

  4. Coagulation profile, gene expression and bioinformatics characterization of coagulation factor X of striped murrel Channa striatus.

    PubMed

    Arasu, Abirami; Kumaresan, Venkatesh; Sathyamoorthi, Akila; Arasu, Mariadhas Valan; Al-Dhabi, Naif Abdullah; Arockiaraj, Jesu

    2016-08-01

    A transcriptome wide analysis of the constructed cDNA library of snakehead murrel Channa striatus revealed a full length cDNA sequence of coagulation factor X. Sequence analysis of C. striatus coagulation factor X (CsFX) showed that the cDNA contained 1232 base pairs (bp) comprising 1209 bp open reading frame (ORF). The ORF region encodes 424 amino acids with a molecular mass of 59 kDa. The polypeptide contains γ-carboxyglutamic acid (GLA) rich domain and two epidermal growth factor (EGF) like domains including EGF-CA domain and serine proteases trypsin signature profile. CsFX exhibited the maximum similarity with fish species such as Stegastes partitus (78%), Poecilia formosa (76%) and Cynoglossus semilaevis (74%). Phylogenetically, CsFX is clustered together with the fish group belonging to Actinopterygii. Secondary structure of factor X includes alpha helix 28.54%, extended strand 20.75%, beta turn 7.78% and random coil 42.92%. A predicted 3D model of CsFX revealed a short α-helix and a Ca(2+) (Gla domain) binding site in the coil. Four disulfide bridges were found in serine protease trypsin profile. Obviously, the highest gene expression (P < 0.05) was noticed in blood. Further, the changes in expression of CsFX was observed after inducing with bacterial (Aeromonas hydrophila) and fungal (Aphanomyces invadans) infections and other synthetic immune stimulants. Variation in blood clotting time (CT), prothrombin time (PT) and activated prothromboplastin time (APTT) was analyzed and compared between healthy and bacterial infected fishes. During infection, PT and APTT showed a declined clotting time due to the raised level of thrombocytes.

  5. Microwave ablation versus laser ablation in occluding lateral veins in goats.

    PubMed

    Wang, Xu-hong; Wang, Xiao-ping; Su, Wen-juan; Yuan, Yuan

    2016-02-01

    Increasing number of endovenous techniques are available for the treatment of saphenous vein reflux and endovenous laser ablation (EVLA) is a frequently used method. A newly developed alternative, based on thermal therapy, is endovenous microwave ablation (EMA). This study evaluated the effect of the two procedures, in terms of coagulation and histological changes, in occluding lateral veins in goats. Twelve animals were randomized into two group, with 6 treated with EMA (EMA group), and the rest 6 with EVLA (EVLA group). Results of coagulation, including coagulation, fibrinolysis and platelet activation, were assessed at three or four different time points: before, immediately after, 24 h (and 48 h) after ablation. The diameter change, a measure of efficacy, was ultrasonographically measured before and 1 month after the ablation. Histological changes were grossly and microscopically evaluated immediately, 1 and 3 month(s) after the ablation. The length of the ablated vein and preoperative average diameter were comparable between the two groups. In both EMA and EVLA groups, several coagulation parameters, fibrinolysis and platelet activation parameters only underwent slight changes. Ultrasound imaging displayed that the diameter reduction of the veins treated by EMA was significantly larger than by EVLA, in consistent with the results of macroscopic examination. Microscopic examination revealed necrosis and thickening of the vein wall, and occlusion of the lumen within 3 months after ablation in both EMA and EVLA groups. It is concluded that EMA is a minimally invasive therapy, which appears to be safe and effective for treatment of lateral veins in goats.

  6. Uniform batch processing using microwaves

    NASA Technical Reports Server (NTRS)

    Barmatz, Martin B. (Inventor); Jackson, Henry W. (Inventor)

    2000-01-01

    A microwave oven and microwave heating method generates microwaves within a cavity in a predetermined mode such that there is a known region of uniform microwave field. Samples placed in the region will then be heated in a relatively identical manner. Where perturbations induced by the samples are significant, samples are arranged in a symmetrical distribution so that the cumulative perturbation at each sample location is the same.

  7. Disinfection of Wastewater by Microwaves.

    DTIC Science & Technology

    1980-01-01

    temperature of the cells before treatment with microwaves nor the temperature of the diluent buffer showed any effect on the rate and extent of...suspension on the sur- vival of E. coli B cells subjected to microwave treatment. 11 2. Effect of the temperature of diluent upon the survival of microwave...the surface of the material to be heated by conduction, convection, and/or radiation. While microwave energy is recognized to have bactericidal ability

  8. How hemostatic agents interact with the coagulation cascade.

    PubMed

    Overbey, Douglas M; Jones, Edward L; Robinson, Thomas N

    2014-08-01

    Hemostasis is a critical component of the preservation of hemodynamic stability and operative visibility during surgery. Initially, hemostasis is achieved via the careful application of direct pressure to allow time for the coagulation cascade to create a fibrin and platelet plug. Other first-line methods of hemostasis in surgery include repair or ligation of the bleeding vessel with sutures, clips, or staples and coagulation of the bleeding site with a thermal energy-based device. When these methods are insufficient to provide adequate hemostasis, topical hemostatic agents can be used to augment the creation of a clot during surgery. A basic understanding of how and where these products interact with the coagulation cascade is essential to achieving optimal hemostasis outcomes.

  9. Mathematical Modeling of Intravascular Blood Coagulation under Wall Shear Stress

    PubMed Central

    Rukhlenko, Oleksii S.; Dudchenko, Olga A.; Zlobina, Ksenia E.; Guria, Georgy Th.

    2015-01-01

    Increased shear stress such as observed at local stenosis may cause drastic changes in the permeability of the vessel wall to procoagulants and thus initiate intravascular blood coagulation. In this paper we suggest a mathematical model to investigate how shear stress-induced permeability influences the thrombogenic potential of atherosclerotic plaques. Numerical analysis of the model reveals the existence of two hydrodynamic thresholds for activation of blood coagulation in the system and unveils typical scenarios of thrombus formation. The dependence of blood coagulation development on the intensity of blood flow, as well as on geometrical parameters of atherosclerotic plaque is described. Relevant parametric diagrams are drawn. The results suggest a previously unrecognized role of relatively small plaques (resulting in less than 50% of the lumen area reduction) in atherothrombosis and have important implications for the existing stenting guidelines. PMID:26222505

  10. [Extracorporeal shockwave lithotripsy in patients with coagulation disorders].

    PubMed

    Ruiz Marcellán, F J; Mauri Cunill, A; Cabré Fabré, P; Argentino Gancedo Rodríguez, V; Güell Oliva, J A; Ibarz Servio, L; Ramón Dalmau, M

    1992-03-01

    During treatment of renal lithiasis with extracorporeal shock wave lithotripsy (ESWL) hemorrhagic events, especially renal hematoma, may present. A coagulation study is warranted in order to institute hemotherapy for blood factor deficiencies. We reviewed the records of 4,000 patients that had undergone ESWL. Of these, 17 (12 males, 5 females) presented coagulation disorders. The bleeding diatheses were due to platelet deficiency in 6 cases, plasma defects in 5, platelet and plasma disorders in 2, and capillary wall defects in 5 cases. The underlying cause was hepatosplenic disease in 12 cases, iatrogenic in 1, connectivopathy and corticoids in 2, and capillary purpura of unknown cause in 2 cases. Due to this protocol, no patient presented hemorrhage or hematoma from shock wave-induced lesions. These results show that a complete coagulation study must be performed in order to institute the necessary measures in patients with disorders of hemostasis due to the high risk of hematoma repeatedly reported in the literature.

  11. Effect of Coagulation of Nodes in an Evolving Complex Network

    NASA Astrophysics Data System (ADS)

    Miura, Wataru; Takayasu, Hideki; Takayasu, Misako

    2012-04-01

    We propose a new type of stochastic network evolution model based on annihilation, creation, and coagulation of nodes, together with the preferential attachment rule. The system reaches a unique quasistatistically steady state in which the distribution of links follows a power law, lifetime of nodes follows an exponential distribution, and the mean number of links grows exponentially with time. The master equation of the model is solved analytically by applying Smoluchowski’s coagulation equation for aerosols. The results indicate that coagulation of nodes in complex networks and mean field analysis of aerosols are similar in both the growth dynamics with irreversible processes and in the steady state statistics. We confirm that the basic properties of the model are consistent with the empirical results of a business transaction network having about 1×106 firms.

  12. Multifrequency acoustics as a probe of mesoscopic blood coagulation dynamics

    NASA Astrophysics Data System (ADS)

    Ganesan, Adarsh; Rajendran, Gokulnath; Ercole, Ari; Seshia, Ashwin

    2016-08-01

    Coagulation is a complex enzymatic polymerisation cascade. Disordered coagulation is common in medicine and may be life-threatening yet clinical assays are typically bulky and/or provide an incomplete picture of clot mechanical evolution. We present the adaptation of an in-plane acoustic wave device: quartz crystal microbalance with dissipation at multiple harmonics to determine the time-evolution of mesoscale mechanical properties of clot formation in vitro. This approach is sensitive to changes in surface and bulk clot structure in various models of induced coagulopathy. Furthermore, we are able to show that clot formation at surfaces has different kinetics and mechanical strength to that in the bulk, which may have implications for the design of bioprosthetic materials. The "Multifrequency acoustics" approach thus enables unique capability to portray biological processes concerning blood coagulation.

  13. Biological and analytical variations of 16 parameters related to coagulation screening tests and the activity of coagulation factors.

    PubMed

    Chen, Qian; Shou, Weiling; Wu, Wei; Guo, Ye; Zhang, Yujuan; Huang, Chunmei; Cui, Wei

    2015-04-01

    To accurately estimate longitudinal changes in individuals, it is important to take into consideration the biological variability of the measurement. The few studies available on the biological variations of coagulation parameters are mostly outdated. We confirmed the published results using modern, fully automated methods. Furthermore, we added data for additional coagulation parameters. At 8:00 am, 12:00 pm, and 4:00 pm on days 1, 3, and 5, venous blood was collected from 31 healthy volunteers. A total of 16 parameters related to coagulation screening tests as well as the activity of coagulation factors were analyzed; these included prothrombin time, fibrinogen (Fbg), activated partial thromboplastin time, thrombin time, international normalized ratio, prothrombin time activity, activated partial thromboplastin time ratio, fibrin(-ogen) degradation products, as well as the activity of factor II, factor V, factor VII, factor VIII, factor IX, and factor X. All intraindividual coefficients of variation (CVI) values for the parameters of the screening tests (except Fbg) were less than 5%. Conversely, the CVI values for the activity of coagulation factors were all greater than 5%. In addition, we calculated the reference change value to determine whether a significant difference exists between two test results from the same individual.

  14. Enhanced WWTP effluent organic matter removal in hybrid ozonation-coagulation (HOC) process catalyzed by Al-based coagulant.

    PubMed

    Jin, Xin; Jin, Pengkang; Hou, Rui; Yang, Lei; Wang, Xiaochang C

    2017-04-05

    A novel hybrid ozonation-coagulation (HOC) process was developed for application in wastewater reclamation. In this process, ozonation and coagulation occurred simultaneously within a single unit. Compared with the conventional pre-ozonation-coagulation process, the HOC process exhibited much better performance in removing dissolved organic matters. In particular, the maximal organic matters removal efficiency was obtained at the ozone dosage of 1mgO3/mg DOC at each pH value (pH 5, 7 and 9). In order to interpret the mechanism of the HOC process, ozone decomposition was monitored. The results indicated that ozone decomposed much faster in the HOC process. Moreover, by using the reagent of O3-resistant hydroxyl radical (OH) probe compound, para-chlorobenzoic acid (pCBA), and electron paramagnetic resonance (EPR) analysis, it was observed that the HOC process generated higher content of OH compared with pre-ozonation process. This indicates that the OH oxidation reaction as the key step can be catalyzed and enhanced by Al-based coagulants and their hydrolyzed products in this developed process. Thus, based on the catalytic effects of Al-based coagulants on ozonation, the HOC process provides a promising alternative to the conventional technology for wastewater reclamation in terms of higher efficiency.

  15. Properties and coagulation performance of coagulant poly-aluminum-ferric-silicate-chloride in water and wastewater treatment.

    PubMed

    Gao, Bao-yu; Yue, Qin-yan; Wang, Bing-jian

    2006-01-01

    An efficient inorganic polymer coagulant, poly-aluminum-ferric-silicate-chloride (PAFSC), was developed using two approaches: (i) hydroxylation of the mixture of AlCl3, FeCl3 and fresh polysilicic acid in different Al/Fe/Si molar ratios to obtain PAFSCc and (ii) hydroxylated poly-aluminum-iron-chloride (PAFC) combined with aged polysilicic acid in different Al/Fe/Si ratios to produce PAFSCm. The properties of PAFSC in comparison with polyaluminum silicate chloride (PASC) and polyferric silicate chloride (PAFC) were characterized by various experimental methods. The effect of Al/Fe/Si molar ratio on the hydrolysis-polymerization process of Al (III) and Fe (III) in PAFSC solutions was examined by pH titration, and the effect of Al/Fe/Si molar ratio on electrokinetic mobility of PAFSC was studied by Zeta potential measurement. The laboratory experiments were performed to evaluate the PAFSC in comparison with polyaluminum chloride (PAC) for the coagulation of synthetic water samples, actual surface water and wastewater. The results show that interactions exist among aluminum species, ferric species and polysilicic acid, and the Al/Fe/Si molar ratio affects the Zeta potential of the hydrolyzate and the coagulating performance. PAFSC achieved a better water treatment result than PAC. At the same basicity (B) value and Al/Fe/Si ratio, PAFSCc has better coagulation performance than PAFSCm. PAFSC is a new type and high efficiency composite inorganic polymer coagulant.

  16. Characteristics of meso-particles formed in coagulation process causing irreversible membrane fouling in the coagulation-microfiltration water treatment.

    PubMed

    Ding, Q; Yamamura, H; Murata, N; Aoki, N; Yonekawa, H; Hafuka, A; Watanabe, Y

    2016-09-15

    In coagulation-membrane filtration water treatment processes, it is still difficult to determine the optimal coagulation condition to minimize irreversible membrane fouling. In microfiltration (MF), meso-particles (i.e., 20 nm-0.5 μm) are thought to play an important role in irreversible membrane fouling, especially their characteristics of particle number (PN) and zeta potential (ZP). In this study, a new nanoparticle tracker combined a high-output violet laser with a microscope was developed to identify the physicochemical characteristics of these microscopic and widely dispersed meso-particles. The effects of pH and coagulant dose on ZP and PN of micro-particles (i.e., >0.5 μm) and meso-particles were investigated, and then coagulation-MF tests were conducted. As the result, irreversible membrane fouling was best controlled for both types of membranes, while meso-particle ZP approached zero at around pH 5.5 for both types of natural water. Since PN was greatest under these conditions, ZP is more important in determining the extent of irreversible membrane fouling than PN. However, the acidic condition to neutralize meso-particles is not suitable for actual operation, as considering residual aluminum concentration, pipe corrosion, and chlorination efficiency. It is therefore necessary to investigate coagulants or other methods for the appropriate modification of meso-particle characteristics.

  17. Adaptive Force Sonorheometry for Assessment of Whole Blood Coagulation

    PubMed Central

    Mauldin, F. William; Viola, Francesco; Hamer, Theresa C.; Ahmed, Eman M.; Crawford, Shawna B.; Haverstick, Doris M.; Lawrence, Michael B.; Walker, William F.

    2010-01-01

    Background: Viscoelastic diagnostics that monitor the hemostatic function of whole blood (WB), such as thromboelastography, have been developed with demonstrated clinical utility. By measuring the cumulative effects of all components of hemostasis, viscoelastic diagnostics have circumvented many of the challenges associated with more common tests of blood coagulation. Methods: We describe a new technology, called sonorheometry, that adaptively applies acoustic radiation force to assess coagulation function in WB. The repeatability (precision) of coagulation parameters was assessed using citrated WB samples. A reference range of coagulation parameters, along with corresponding measurements from prothrombin time (PT) and partial thromboplastin time (PTT), were obtained from WB samples of 20 healthy volunteers. In another study, sonorheometry monitored anticoagulation with heparin (0 – 5 IU/ml) and reversal from varied dosages of protamine (0 – 10 IU/ml) in heparinized WB (2 IU/ml). Results: Sonorheometry exhibited low CVs for parameters: clot initiation time (TC1), < 7%; clot stabilization time (TC2), < 6.5%; and clotting angle (θ), < 3.5%. Good correlation was observed between clotting times, TC1 and TC2, and PTT (r = 0.65 and 0.74 respectively; n=18). Linearity to heparin dosage was observed with average linearity r > 0.98 for all coagulation parameters. We observed maximum reversal of heparin anticoagulation at protamine to heparin ratios of 1.4:1 from TC1 (P=0.6) and 1.2:1 from θ (P=0.55). Conclusions: Sonorheometry is a non-contact method for precise assessment of WB coagulation. PMID:20096680

  18. Physics of the Microwave Oven

    ERIC Educational Resources Information Center

    Vollmer, Michael

    2004-01-01

    This is the first of two articles about the physics of microwave ovens. This article deals with the generation of microwaves in the oven and includes the operation of the magnetrons, waveguides and standing waves in resonant cavities. It then considers the absorption of microwaves by foods, discussing the dielectric relaxation of water,…

  19. Microwave-assisted Chemical Transformations

    EPA Science Inventory

    In recent years, there has been a considerable interest in developing sustainable chemistries utilizing green chemistry principles. Since the first published report in 1986 by Gedye and Giguere on microwave assisted synthesis in household microwave ovens, the use of microwaves as...

  20. Peculiarities of coagulation action of IR lasers (1-3 um) radiation on cornea

    NASA Astrophysics Data System (ADS)

    Berezin, Yuri D.; Boiko, Ernest V.; Volkov, Venjamin V.; Danilichev, Vladimir F.; Ganin, Dmitry V.; Gatzu, Andrey F.; Smirnov, Nicolay N.; Lazo, Victor V.; Tkachuk, Alexandra M.

    1996-04-01

    Antiviral, antibacterial, antitumoral effects of laser coagulation are now of great importance in clinical ophthalmology for different corneal diseases treatment. One can note, that nowadays solid-state free-mode pulsed near-and-mid-infrared lasers with the 1.3 - 3.0 micrometers wavelengths may become widespreadly accepted in this field of ophthalmosurgery. The corneal tissue absorption coefficients for these wavelengths are lying from some parts to several thousand cm-1. Thus, by proper selection of laser wavelength, possibility is appeared to coagulate precisely the seat of pathological alterations without damaging of more deeper, non changed corneal tissue. In our work the comparative experimental study results of rabbit cornea coagulation after exposure with using of different IR lasers (with 1.32; 1.54; 1.96; 2.09 and 2.84 micrometers wavelengths) are presented. Pulse duration was about 10-3 s. The subthreshold, threshold and superthreshold energy levels were studied. Threshold energies were registered if slightly noticed coagulative changes appeared in exposed volume of corneal tissue. The cornea response resulting from laser radiation exposure was evaluated by clinical examination, slit lamp biomicroscopy, light microscopy, fluorescent staining and biochemistry. For all wavelengths initial damage was found within the cornea layers. Superthreshold injury revealed the same picture except that for 1.32 micrometers the threefold increase of the threshold energy caused additionally iris injury. The damages of the cornea were marked near the surface, stretched to more deeper layers, and damage zones were extended from the epithelium for 2.84 micrometers wavelength to whole cornea thickness for 1.32 and 1.54 micrometers wavelengths and have intermediate position for 1.96 and 2.09 micrometers wavelengths, depending on the corneal absorption coefficient. Quantitative results of threshold energy levels were calculated by probit-analysis. The radiant exposure (HD50

  1. Interpretation of coagulation test results under direct oral anticoagulants.

    PubMed

    Mani, H

    2014-06-01

    Diagnostic of global coagulation parameters is part of the daily clinical routine practice in conservative as well in operative disciplines. The correct interpretation of in vitro test results in context to the ex vivo influence of anticoagulant drugs and the in vivo hemostatic system of the individual patient is dependent on the doctors clinical and laboratory experience. This article shortly reviews the laboratory interference of oral anticoagulants including the target-specific inhibitors dabigatran, rivaroxaban and apixaban on coagulation parameters and discusses the potential of several methods for measuring the anticoagulant effect of the direct oral anticoagulants.

  2. Sonoclot(®)-based method to detect iron enhanced coagulation.

    PubMed

    Nielsen, Vance G; Henderson, Jon

    2016-07-01

    Thrombelastographic methods have been recently introduced to detect iron mediated hypercoagulability in settings such as sickle cell disease, hemodialysis, mechanical circulatory support, and neuroinflammation. However, these inflammatory situations may have heme oxygenase-derived, coexistent carbon monoxide present, which also enhances coagulation as assessed by the same thrombelastographic variables that are affected by iron. This brief report presents a novel, Sonoclot-based method to detect iron enhanced coagulation that is independent of carbon monoxide influence. Future investigation will be required to assess the sensitivity of this new method to detect iron mediated hypercoagulability in clinical settings compared to results obtained with thrombelastographic techniques.

  3. Extremely refractory Kawasaki disease with disseminated intravascular coagulation.

    PubMed

    Koh, Young Kwon; Lee, Jae Hee; Park, Yeong Bong

    2017-03-07

    Disseminated intravascular coagulation is a rare complication of Kawasaki disease and appears in <0.1% of Kawasaki disease patients. We report a case of refractory Kawasaki disease complicated with disseminated intravascular coagulation and giant coronary aneurysm. A 5-month-old boy presented with Kawasaki disease with coagulopathy. Although the coagulopathy improved after fresh-frozen plasma and antithrombin-III administration, the fever persisted despite two rounds of intravenous immunoglobulin, along with intravenous methylprednisolone pulse therapy and infliximab administration. Despite all efforts to treatment, the patient had giant coronary aneurysms and died suddenly.

  4. Reincarnation of ancient links between coagulation and complement.

    PubMed

    Conway, E M

    2015-06-01

    Throughout evolution, organisms have developed means to contain wounds by simultaneously limiting bleeding and eliminating pathogens and damaged host cells via the recruitment of innate defense mechanisms. Disease emerges when there is unchecked activation of innate immune and/or coagulation responses. A key component of innate immunity is the complement system. Concurrent excess activation of coagulation and complement - two major blood-borne proteolytic pathways - is evident in numerous diseases, including atherosclerosis, diabetes, venous thromboembolic disease, thrombotic microangiopathies, arthritis, cancer, and infectious diseases. Delineating the cross-talk between these two cascades will uncover novel therapeutic insights.

  5. Strongly differentiable solutions of the discrete coagulation-fragmentation equation

    NASA Astrophysics Data System (ADS)

    McBride, A. C.; Smith, A. L.; Lamb, W.

    2010-08-01

    We examine an infinite system of ordinary differential equations that models the binary coagulation and multiple fragmentation of clusters. In contrast to previous investigations, our analysis does not involve finite-dimensional truncations of the system. Instead, we treat the problem as an infinite-dimensional differential equation, posed in an appropriate Banach space, and apply perturbation results from the theory of strongly continuous semigroups of operators. The existence and uniqueness of physically meaningful solutions are established for uniformly bounded coagulation rates but with no growth restrictions imposed on the fragmentation rates.

  6. Quasi-dynamical analysis and real-time tissue temperature monitoring during laser vaporization

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Ray, Aditi; Jebens, Dave; Chia, Ray; Hasenberg, Tom

    2014-03-01

    Vaporization and coagulation are two fundamental processes that can be performed during laser-tissue ablation. We demonstrated a method allowing quasi-dynamically observing of the cross-sectional images of tissue response during ablation. The results showed that coagulation depth is relatively constant during vaporization, which supports the excellent hemostasis of green laser benign prostate hyperplasia (BPH) treatment. We also verified a new technology for real-time, in situ tissue temperature monitoring, which may be promising for in vivo tissue vaporization degree feedback during laser ablation to improve the vaporization efficiency and avoid complications.

  7. Microwave effects on isolated chick embryo hearts

    SciTech Connect

    Caddemi, A.; Tamburello, C.C.; Zanforlin, L.; Torregrossa, M.V.

    1986-01-01

    This study was designed to examine the effects of microwaves on the electric activity of hearts as a means of elucidating interactive mechanisms of nonionizing radiation with cardiac tissue. Experiments were performed on isolated hearts of 9-12-day-old chick embryos placed in small petri dishes. Oxygenated isotonic Ringer's solution at 37 degrees C permitted heart survival. Samples were irradiated at 2.45 GHz with a power density of 3 mW/cm2. The heart signal was detected with a glass micropipet inserted into the sinoatrial node and examined by means of a Berg-Fourier analyzer. Pulsed microwaves caused the locking of the heartbeat to the modulation frequency, whereas continuous wave irradiation might have induced slight bradycardia. Pulsed fields induced stimulation or regularization of the heartbeat in arrhythmia, fibrillation, or arrest of the heart.

  8. Handbook of microwave testing

    NASA Astrophysics Data System (ADS)

    Laverghetta, T. S.

    A description of microwave test equipment is presented, taking into account signal generators, signal detection/indicating devices, auxiliary testing devices, and microwave systems. Low power, medium power, high power, and peak power measurements are considered along with noise measurements, spectrum analyzer measurements, active testing, antenna measurements, and automatic testing. Attention is given to phase noise, Q measurements, the Time Domain Reflectometry (TDR) measurement, swept impedance, noise sources, noise meters, manual noise measurements, automatic noise figure measurements, gain, gain compression, intermodulation, the third order intercept, and questions of spectral purity.

  9. Microwave Frequency Polarizers

    NASA Technical Reports Server (NTRS)

    Ha, Vien The; Mirel, Paul; Kogut, Alan J.

    2013-01-01

    This article describes the fabrication and analysis of microwave frequency polarizing grids. The grids are designed to measure polarization from the cosmic microwave background. It is effective in the range of 500 to 1500 micron wavelength. It is cryogenic compatible and highly robust to high load impacts. Each grid is fabricated using an array of different assembly processes which vary in the types of tension mechanisms to the shape and size of the grids. We provide a comprehensive study on the analysis of the grids' wire heights, diameters, and spacing.

  10. EDITORIAL: Microwave Moisture Measurements

    NASA Astrophysics Data System (ADS)

    Kaatze, Udo; Kupfer, Klaus; Hübner, Christof

    2007-04-01

    Microwave moisture measurements refer to a methodology by which the water content of materials is non-invasively determined using electromagnetic fields of radio and microwave frequencies. Being the omnipresent liquid on our planet, water occurs as a component in most materials and often exercises a significant influence on their properties. Precise measurements of the water content are thus extremely useful in pure sciences, particularly in biochemistry and biophysics. They are likewise important in many agricultural, technical and industrial fields. Applications are broad and diverse, and include the quality assessment of foodstuffs, the determination of water content in paper, cardboard and textile production, the monitoring of moisture in sands, gravels, soils and constructions, as well as the measurement of water admixtures to coal and crude oil in reservoirs and in pipelines. Microwave moisture measurements and evaluations require insights in various disciplines, such as materials science, dielectrics, the physical chemistry of water, electrodynamics and microwave techniques. The cooperation of experts from the different fields of science is thus necessary for the efficient development of this complex discipline. In order to advance cooperation the Workshop on Electromagnetic Wave Interaction with Water and Moist Substances was held in 1993 in Atlanta. It initiated a series of international conferences, of which the last one was held in 2005 in Weimar. The meeting brought together 130 scientists and engineers from all over the world. This special issue presents a collection of some selected papers that were given at the event. The papers cover most topics of the conference, featuring dielectric properties of aqueous materials, electromagnetic wave interactions, measurement methods and sensors, and various applications. The special issue is dedicated to Dr Andrzej W Kraszewski, who died in July 2006 after a distinguished career of 48 years in the research of

  11. High power microwave generator

    DOEpatents

    Minich, Roger W.

    1988-01-01

    A device (10) for producing high-powered and coherent microwaves is described. The device comprises an evacuated, cylindrical, and hollow real cathode (20) that is driven to inwardly field emit relativistic electrons. The electrons pass through an internally disposed cylindrical and substantially electron-transparent cylindrical anode (24), proceed toward a cylindrical electron collector electrode (26), and form a cylindrical virtual cathode (32). Microwaves are produced by spatial and temporal oscillations of the cylindrical virtual cathode (32), and by electrons that reflex back and forth between the cylindrical virtual cathode (32) and the cylindrical real cathode (20).

  12. Electronic beam steering used with a toroidal HIFU transducer substantially increases the coagulated volume.

    PubMed

    Vincenot, Jeremy; Melodelima, David; Chavrier, Françoise; Vignot, Alexandre; Kocot, Anthony; Chapelon, Jean-Yves

    2013-07-01

    Treatment with high-intensity focused ultrasound is well established but requires extended treatment time. A device composed of 256 elements arranged on a toroidal transducer was developed to increase the coagulated volume. When all the elements are working in phase for 40 s, a volume of 6-8 cm(3) can be ablated. However, the mechanical juxtaposition of single lesions is still necessary for treating one tumor with a diameter of 2 cm. The objective of this study was to combine this toroidal transducer geometry with electronic beam steering to ablate tumors with adequate normal tissue margins and without any mechanical displacement of the high-intensity focused ultrasound device. In vitro tests demonstrated that the coagulated volume obtained from 130 s of total exposure has an average diameter of 41.4 ± 4.0 mm and an average length of 53.3 ± 6.1 mm. This single lesion can be used to treat various size of metastasis, located at depths in the liver ranging 5-45 mm.

  13. Endothelial Dysfunction and Altered Coagulation As Mediators of Thromboembolism in Behçet Disease.

    PubMed

    Butta, Nora V; Fernández-Bello, Ihosvany; López-Longo, Francisco J; Jiménez-Yuste, Víctor

    2015-09-01

    Behçet disease (BD) is a rare multisystem, inflammatory disease of unknown etiology with vascular involvement and associated thrombogenicity. This review aims to describe the involvement of various mediators in endothelial cell damage and in the hypercoagulable state of BD. The scenario of the chronic inflammation present in BD shows an increased oxidative condition that contributes to endothelial cell damage and induces platelet, leukocyte, and endothelial cell activation through the release of proinflammatory cytokines and chemokines. These factors, together with the increased levels of homocysteine observed in BD patients, induce the endothelial cell expression of adhesion molecules (VCAM-1 and ICAM-1) and tissue factor; the release of cytokines, soluble CD40L (sCD40L), matrix metalloproteinase-9, and blood coagulation factor V; the inhibition of fibrinolysis; the disruption of nitric oxide metabolism; and the increase in platelet reactivity and lipid peroxidation. Endothelial cell dysfunction leads to a prothrombotic and antifibrinolytic phenotype in BD patients. Increased levels of homocysteine, fibrinogen, and plasminogen activator inhibitor type 1 seem to be involved in the procoagulant condition of this pathology that has been verified by end-point tests as well as by global coagulation tests.

  14. Evaluation of the efficacy and safety of rivaroxaban using a computer model for blood coagulation.

    PubMed

    Burghaus, Rolf; Coboeken, Katrin; Gaub, Thomas; Kuepfer, Lars; Sensse, Anke; Siegmund, Hans-Ulrich; Weiss, Wolfgang; Mueck, Wolfgang; Lippert, Joerg

    2011-04-22

    Rivaroxaban is an oral, direct Factor Xa inhibitor approved in the European Union and several other countries for the prevention of venous thromboembolism in adult patients undergoing elective hip or knee replacement surgery and is in advanced clinical development for the treatment of thromboembolic disorders. Its mechanism of action is antithrombin independent and differs from that of other anticoagulants, such as warfarin (a vitamin K antagonist), enoxaparin (an indirect thrombin/Factor Xa inhibitor) and dabigatran (a direct thrombin inhibitor). A blood coagulation computer model has been developed, based on several published models and preclinical and clinical data. Unlike previous models, the current model takes into account both the intrinsic and extrinsic pathways of the coagulation cascade, and possesses some unique features, including a blood flow component and a portfolio of drug action mechanisms. This study aimed to use the model to compare the mechanism of action of rivaroxaban with that of warfarin, and to evaluate the efficacy and safety of different rivaroxaban doses with other anticoagulants included in the model. Rather than reproducing known standard clinical measurements, such as the prothrombin time and activated partial thromboplastin time clotting tests, the anticoagulant benchmarking was based on a simulation of physiologically plausible clotting scenarios. Compared with warfarin, rivaroxaban showed a favourable sensitivity for tissue factor concentration inducing clotting, and a steep concentration-effect relationship, rapidly flattening towards higher inhibitor concentrations, both suggesting a broad therapeutic window. The predicted dosing window is highly accordant with the final dose recommendation based upon extensive clinical studies.

  15. Cyanotic congenital heart disease (CCHD): focus on hypoxemia, secondary erythrocytosis, and coagulation alterations.

    PubMed

    Zabala, Luis M; Guzzetta, Nina A

    2015-10-01

    Children with cyanotic congenital heart disease (CCHD) have complex alterations in their whole blood composition and coagulation profile due to long-standing hypoxemia. Secondary erythrocytosis is an associated physiological response intended to increase circulating red blood cells and oxygen carrying capacity. However, this response is frequently offset by an increase in whole blood viscosity that paradoxically reduces blood flow and tissue perfusion. In addition, the accompanying reduction in plasma volume leads to significant deficiencies in multiple coagulation proteins including platelets, fibrinogen and other clotting factors. On the one hand, these patients may suffer from severe hyperviscosity and subclinical 'sludging' in the peripheral vasculature with an increased risk of thrombosis. On the other hand, they are at an increased risk for postoperative hemorrhage due to a complex derangement in their hemostatic profile. Anesthesiologists caring for children with CCHD and secondary erythrocytosis need to understand the pathophysiology of these alterations and be aware of available strategies that lessen the risk of bleeding and/or thrombosis. The aim of this review is to provide an updated analysis of the systemic effects of long-standing hypoxemia in children with primary congenital heart disease with a specific focus on secondary erythrocytosis and hemostasis.

  16. Ipomoea dasysperma seed gum: an effective natural coagulant for the decolorization of textile dye solutions.

    PubMed

    Sanghi, Rashmi; Bhattacharya, Bani; Dixit, Awantika; Singh, Vandana

    2006-10-01

    An investigation of dye decolorization from synthetic dye solutions using the non-ionic, water-soluble, high molecular weight seed gums Ipomoea dasysperma and guar gum as coagulants was undertaken. The use of galactomannans derived from plants in this system presents a sustainable method of textile effluent treatment. These natural coagulants extracted from plants proved to be workable alternatives to conventional coagulants like polyaluminum chloride, as they are biodegradable, safe to human health, are cost effective when compared to imported chemicals and have a wider effective dosage range for flocculation of various colloidal suspensions. Coagulant dose and coagulation pH are important factors influencing the mechanism of coagulation. Also the type and chemical structure of the dye plays an important role in the coagulation process. The seed gums alone were found to be effective for decolorization of direct dye and in combination with PAC their coagulation efficiency was well extended even for reactive and acid dyes.

  17. Vascular determinants of cancer stem cell dormancy--do age and coagulation system play a role?

    PubMed

    Rak, Janusz; Milsom, Chloe; Yu, Joanne

    2008-01-01

    demand (vascular dependence) of CSC and their progeny; (iii) the interplay between CSCs and the vascular system during the process of metastasis, and especially (iv) the impact of the coagulation system on the properties of CSC and their niches. We will use the oncogene-driven expression of tissue factor (TF) in cancer cells as a paradigm in this regard, as TF represents a common denominator of several vascular processes that commonly occur in cancer, most notably coagulation and angiogenesis. In so doing we will explore the therapeutic implications of targeting TF and the coagulation system to modulate the dynamics of tumour growth and tumour dormancy.

  18. Tissue factor activity under flow.

    PubMed

    Diamond, Scott L

    2010-04-01

    Coagulation processes under flow conditions are fundamentally different when compared to whole blood clotting in a tube. Due to red blood cell migration toward the center of the vessel, platelet concentrations are elevated several-fold in the plasma layer near the wall or thrombus. Evaluation of platelet function, coagulation proteases, and pharmacological agents can utilize closed systems of constant volume that lack flow (eg. intracellular calcium measurement, automated calibrated thrombography) or include flow (eg. aggregometry or cone-and-plate viscometry). However, these laboratory approaches fail to recreate the fact that intravascular thrombosis is an open system where blood is continually flowing over a thrombotic site. In open systems, the rapid accumulation of platelets at a surface leads to platelet concentrations greatly exceeding those found in whole blood and the delivery/removal of species by convection may impact the efficacy of pharmacological agents. During a clotting event under flow, platelets can accumulate via adhesion receptors to concentrations that are 10 to 50-fold higher than that of platelet-rich plasma. Using controlled in vitro perfusions of whole blood, it is possible to determine the critical level of surface tissue factor needed to trigger full scale coagulation on collagen. Such in vitro perfusion systems also allow a determination of the potency of anti-platelet agents as a function of wall shear rate.

  19. Wound healing in hemophilia B mice and low tissue factor mice.

    PubMed

    Monroe, Dougald M; Mackman, Nigel; Hoffman, Maureane

    2010-04-01

    Wound healing involves a number of physiologic mechanisms including coagulation, inflammation, formation of granulation tissue, and tissue remodeling. Coagulation with robust thrombin generation leading to fibrin formation is necessary for wound healing. It is less clear if there is a requirement for ongoing coagulation to support tissue remodeling. We have studied wound healing in mice with defects in both the initiation (low tissue factor) and propagation (hemophilia B) phases. In hemophilia B mice, dermal wound healing is delayed; this delay is associated with bleeding into the granulation tissue. Mice can be treated with replacement therapy (factor IX) or bypassing agents (factor VIIa) to restore thrombin generation. If treated just prior to wound placement, mice will have normal hemostasis in the first day of wound healing. As the therapeutic agents clear, the mice will revert to hemophilic state. If the primary role of coagulation in wound healing is to provide a stable platelet/fibrin plug that is loaded with thrombin, then treating hemophilic animals just prior to wound placement should restore normal wound healing. The results from this study did not support that hypothesis. Instead the results show that restoring thrombin generation only at the time of wound placement did not improve the delayed wound healing. In preliminary studies on low tissue factor mice, there also appears to be a delay in wound healing with evidence of bleeding into the granulation tissue. The current data suggests that ongoing coagulation function needs to be maintained to support a normal wound healing process.

  20. An evaluation of the effect of microwave irradiation on bone decalcification aimed to DNA extraction.

    PubMed

    Imaizumi, Kazuhiko; Taniguchi, Kei; Ogawa, Yoshinori

    2013-09-01

    An effect of intermittent microwave irradiation on decalcification of compact bone followed by DNA extraction was verified. In order to perform quantitative analysis regarding the degree of decalcification, Cubic bone specimens were prepared from bovine metacarpal bone and micro-focus X-ray CT imaging was applied to measure precise volume of decalcified area in the cubes. Microwave irradiation was performed under strict control of temperature using commercially available experimental device which is designed for advancing tissue fixation, decalcification, and antigen-antibody reaction by intermittent microwave. The integrity of the DNA obtained from irradiated specimen was also examined by PCR analysis. The results of morphological analysis with CT imaging showed that microwave irradiation has a positive effect on decalcification though that effect is not so drastic. The results obtained from PCR analysis showed that microwave irradiation decrease amplifiable DNA, suggesting that we should be careful to use microwave for the purpose of bone DNA extraction.

  1. The Coagulant Type Influence on Removal Efficiency of 5- and 6-Ring Pahs During Water Coagulation Process

    NASA Astrophysics Data System (ADS)

    Nowacka, Anna; Włodarczyk-Makuła, Maria

    2014-12-01

    The article presents results on investigation of the removal efficiency of selected 5- and 6-ring polycyclic aromatic hydrocarbons (benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[j]fluoranthene, benzo[g,h,i]perylene, indeno[1,2,3-cd]pyrene, dibenzo[a,h]anthracene) from water during coagulation and sedimentation process. Two pre-hydrolyzed aluminum coagulants: PAX XL 19H and FLOKOR 105V were chosen for research. Process was carried out at optimum process parameters: rapid-mixing - 3 min at the rotational speed of 200 rpm, slow mixing - 10 min at 30 rpm, sedimentation - 60 min. The removal effectiveness was dependant on coagulant type and its composition. Better results in the removal of 5-and 6-ring PAHs were obtained after application of FLOKOR 105V (lower aluminum content) than after using PAX XL 19H.

  2. In vivo microwave-based thermoacoustic tomography of rats (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Lin, Li; Zhou, Yong; Wang, Lihong V.

    2016-03-01

    Microwave-based thermoacoustic tomography (TAT), based on the measurement of ultrasonic waves induced by microwave pulses, can reveal tissue dielectric properties that may be closely related to the physiological and pathological status of the tissues. Using microwaves as the excitation source improved imaging depth because of their deep penetration into biological tissues. We demonstrate, for the first time, in vivo microwave-based thermoacoustic imaging in rats. The transducer is rotated around the rat in a full circle, providing a full two-dimensional view. Instead of a flat ultrasonic transducer, we used a virtual line detector based on a cylindrically focused transducer. A 3 GHz microwave source with 0.6 µs pulse width and an electromagnetically shielded transducer with 2.25 MHz central frequency provided clear cross-sectional images of the rat's body. The high imaging contrast, based on the tissue's rate of absorption, and the ultrasonically defined spatial resolution combine to reveal the spine, kidney, muscle, and other deeply seated anatomical features in the rat's abdominal cavity. This non-invasive and non-ionizing imaging modality achieved an imaging depth beyond 6 cm in the rat's tissue. Cancer diagnosis based on information about tissue properties from microwave band TAT can potentially be more accurate than has previously been achievable.

  3. Demonstration of the Coagulation and Diffusion of Homemade Slime Prepared under Acidic Conditions without Borate

    ERIC Educational Resources Information Center

    Isokawa, Naho; Fueda, Kazuki; Miyagawa, Korin; Kanno, Kenichi

    2015-01-01

    Poly(vinyl alcohol) (PVA) precipitates in many kinds of aqueous salt solutions. While sodium sulfate, a coagulant for PVA fiber, precipitates PVA to yield a white rigid gel, coagulation of PVA with aluminum sulfate, a coagulant for water treatment, yields a slime-like viscoelastic fluid. One type of homemade slime is prepared under basic…

  4. Variable frequency microwave furnace system

    DOEpatents

    Bible, Don W.; Lauf, Robert J.

    1994-01-01

    A variable frequency microwave furnace system (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34) for testing or other selected applications. The variable frequency microwave furnace system (10) includes a microwave signal generator (12) or microwave voltage-controlled oscillator (14) for generating a low-power microwave signal for input to the microwave furnace. A first amplifier (18) may be provided to amplify the magnitude of the signal output from the microwave signal generator (12) or the microwave voltage-controlled oscillator (14). A second amplifier (20) is provided for processing the signal output by the first amplifier (18). The second amplifier (20) outputs the microwave signal input to the furnace cavity (34). In the preferred embodiment, the second amplifier (20) is a traveling-wave tube (TWT). A power supply (22) is provided for operation of the second amplifier (20). A directional coupler (24) is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

  5. Variable frequency microwave furnace system

    DOEpatents

    Bible, D.W.; Lauf, R.J.

    1994-06-14

    A variable frequency microwave furnace system designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity for testing or other selected applications. The variable frequency microwave furnace system includes a microwave signal generator or microwave voltage-controlled oscillator for generating a low-power microwave signal for input to the microwave furnace. A first amplifier may be provided to amplify the magnitude of the signal output from the microwave signal generator or the microwave voltage-controlled oscillator. A second amplifier is provided for processing the signal output by the first amplifier. The second amplifier outputs the microwave signal input to the furnace cavity. In the preferred embodiment, the second amplifier is a traveling-wave tube (TWT). A power supply is provided for operation of the second amplifier. A directional coupler is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter is provided for measuring the power delivered to the microwave furnace. A second power meter detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load. 5 figs.

  6. Characterization of the biological effect of fish fibrin glue in experiments on rats: Immunological and coagulation studies

    PubMed Central

    Laidmäe, Ivo; Salum, Tiit; Sawyer, Evelyn S.; Janmey, Paul A.; Uibo, Raivo

    2011-01-01

    Fibrin glues (FG) of human or bovine origin are widely used for haemostasis and wound healing. In addition FGs are studied in many biomedical areas like cell therapy or tissue engineering. As any mammalian plasma products FG-s pose risk of transmission of bacteria, viruses, or prions and may compromise patient homeostasis. In this study, we examined coagulation parameters and immunological status of rats treated with salmon-derived FG. We evaluated the changes in thrombin time, prothrombin activity, and presence of antibodies on 46 Wistar rats. This study shows that salmon-derived FG, injected intraperitoneally, does not cause coagulation disturbances in the peripheral blood. After a first challenge with salmon-derived FG there were low but detectable amounts of antibodies revealed by ELISA and immunoblot. After a second administration there was substantial elevation of antibodies to FG components and other copurifying plasma proteins. Antibody reactivity to human Factor Va, revealed in three animals, was not associated with FG application. Taken together, blood immunological and coagulation parameters support the suitability of salmon-derived FG in the development of fibrin sealants for medical use. PMID:19484773

  7. Holographic assessment of a hypothesized microwave hearing mechanism.

    PubMed

    Frey, A H; Coren, E

    1979-10-12

    Exposure of the head to pulse-modulated microwaves induces the perception of a sound. It has been hypothesized that the electromagnetic energy is converted to acoustic energy in the skull and then conducted through the bone. Dynamic time-averaged interferometric holography showed that the predicted motion of head tissue did not occur. An alternative locus for this hearing effect is suggested.

  8. Leakage of Microwave Ovens

    ERIC Educational Resources Information Center

    Abdul-Razzaq, W.; Bushey, R.; Winn, G.

    2011-01-01

    Physics is essential for students who want to succeed in science and engineering. Excitement and interest in the content matter contribute to enhancing this success. We have developed a laboratory experiment that takes advantage of microwave ovens to demonstrate important physical concepts and increase interest in physics. This experiment…

  9. Electronically Tuned Microwave Oscillator

    NASA Technical Reports Server (NTRS)

    Lakshminarayana, Mysore

    1987-01-01

    Features include low phase noise and frequency stability. Bias-tuned, low-phase-noise microwave oscillator circuit based on npn bipolar transistor and dielectric resonator. Operating at frequency of about 8.4 GHz, oscillator adjusted to give low phase noise, relatively flat power output versus frequency, and nearly linear frequency versus bias voltage.

  10. Acoustic determination of early stages of intravascular blood coagulation.

    PubMed

    Uzlova, Svetlana G; Guria, Konstantin G; Guria, Georgy Th

    2008-10-13

    The blood coagulation system (BCS) is a complex biological system playing a principal role in the maintenance of haemostasis. Insufficient activity of the BCS may lead to bleeding and blood loss (e.g. in the case of haemophilia). On the other hand, excessive activity may cause intravascular blood coagulation, thromboses and embolization. Most of the methods currently used for BCS monitoring suffer from the major disadvantage of being invasive. The purpose of the present work is to demonstrate the feasibility of using ultrasonic methods for non-invasive registration of the early stages of blood coagulation processes in intensive flows. With this purpose, a special experimental set-up was designed, facilitating the simultaneous detection of optical and acoustic signals during the clotting process. It was shown that (i) as microemboli appear in the flow during the early stage of blood coagulation, the intensity of the Doppler signal increases twofold, and (ii) microemboli formation in the early stages of blood clotting always reveals itself through an acoustic contrast. Both of these effects are well defined, so we hope that they may be used for non-invasive BCS monitoring in clinical practice.

  11. Dust Coagulation in Infalling Protostellar Envelopes I. Compact Grains

    NASA Technical Reports Server (NTRS)

    Yorke, H.; Suttner, G.; Lin, D.

    1999-01-01

    Dust plays a key role in the optical, thermodynamic and gas dynamical behavior of collapsing molecular cores. Because of relative velocities of the individual dust grains, coagulation and shattering can modify the grain size distribution and due to corresponding changes in the medium's opacity significantly influence the evolution during early phase of star formation.

  12. Dust Coagulation in Infalling Protostellar Envelopes I. Compact Grains

    NASA Technical Reports Server (NTRS)

    Yorke, H.; Lin, D.; Suttner, G.

    1999-01-01

    Dust plays a key role in the optical, thermodynamic and gas dynamical behavior of collapsing molecular cores. Because of relative velocities of the individual dust grains, coagulation and shattering can modify the grain size distribution and -- due to corresponding changes in the medium's opacity significantly -- influence the evolution during early phases of star formation.

  13. Membrane coagulation bioreactor (MCBR) for drinking water treatment.

    PubMed

    Tian, Jia-Yu; Liang, Heng; Li, Xing; You, Shi-jie; Tian, Sen; Li, Gui-bai

    2008-08-01

    In this paper, a novel submerged ultrafiltration (UF) membrane coagulation bioreactor (MCBR) process was evaluated for drinking water treatment at a hydraulic retention time (HRT) as short as 0.5h. The MCBR performed well not only in the elimination of particulates and microorganisms, but also in almost complete nitrification and phosphate removal. As compared to membrane bioreactor (MBR), MCBR achieved much higher removal efficiencies of organic matter in terms of total organic carbon (TOC), permanganate index (COD(Mn)), dissolved organic carbon (DOC) and UV absorbance at 254nm (UV(254)), as well as corresponding trihalomethanes formation potential (THMFP) and haloacetic acids formation potential (HAAFP), due to polyaluminium chloride (PACl) coagulation in the bioreactor. However, the reduction of biodegradable dissolved organic carbon (BDOC) and assimilable organic carbon (AOC) by MCBR was only 8.2% and 10.1% higher than that by MBR, indicating that biodegradable organic matter (BOM) was mainly removed through biodegradation. On the other hand, the trans-membrane pressure (TMP) of MCBR developed much lower than that of MBR, which implies that coagulation in the bioreactor could mitigate membrane fouling. It was also identified that the removal of organic matter was accomplished through the combination of three unit effects: rejection by UF, biodegradation by microorganism and coagulation by PACl. During filtration operation, a fouling layer was formed on the membranes surface of both MCBR and MBR, which functioned as a second membrane for further separating organic matter.

  14. Removal and Transformation of Estrogens During the Coagulation Process

    EPA Science Inventory

    Estrogenic compounds have been shown to be present in surface waters, leading to concerns over the possible presence of endocrine disrupting compounds in finished drinking waters. Bench-scale studies (jar tests) simulating coagulation were conducted to evaluate the ability of tw...

  15. Application performance of a new coagulant in wastewater reuse.

    PubMed

    Fu, Ying; Wang, Jingzhi; Wang, Yanzheng; Lu, Ningning

    2016-01-01

    Ultraviolet (UV) absorption characteristics of poly-Al-Zn-Fe (PAZF), a polymerized coagulant containing three kinds of metallic elements prepared from a galvanized-aluminum slag, was analyzed by UV-visible spectrophotometry during its polymerization process. Pollutant removal by PAZF in treating various wastewaters was investigated, in comparison with that of polyaluminum chloride (PAC). The results showed that PAZF can be applied to different wastewaters and had excellent coagulation behavior due to its special internal composition. Various complicated substances having different absorption wavelengths and polymeric properties were produced during the PAZF polymerization process, and the structures of these complicated substances were adjusted continuously with the increasing of the polymerization time. PAZF posed better turbidity and organic matter (chemical oxygen demand, COD(Cr)) removal than PAC for different wastewaters, and the required dosage of PAZF was far lower than that of PAC when achieving the same coagulation performance. For pharmaceutical, sugar, dyeing, simulated pesticide and landscape wastewaters, PAZF gave higher removal of turbidity or COD(Cr) than PAC, by up to 79.5% (coagulant dose: 74 mg/L) or 16% (148 mg/L), 13.4% (111 mg/L) or 10% (185 mg/L), 26.5% (148 mg/L) or 8.1% (18.5 mg/L), 40% (18.5 mg/L) or 13.4% (111 mg/L), and 5% (70 mg/L) or 5% (70 mg/L), respectively.

  16. [Breakage and regrowth of flocs coagulation with polyaluminum chloride (PACl)].

    PubMed

    Zhang, Zhong-Guo; Luan, Zhao-Kun; Zhao, Ying; Cui, Jian-Hua; Chen, Zhao-Yang; Li, Yan-Zhong

    2007-02-01

    The conventional jar test and the monitoring technique of floc size in line were employed to investigate the breakage and regrowth of the flocs formed by PACl. It was found that the breakage and regrowth of flocs varied with coagulation zones. The flocs formed in stabilization zone were of high strength and difficult to break, and could regrow better after broken, with the recovery factor of up to 259%. The flocs formed in charge neutralization zone were of the lowest strength and prone to break, but could reform completely after broken. The flocs formed in restabilization and sweep coagulation zones were also of high strength and difficult to break, but significantly irreversible after broken. The recovery factor of the broken flocs in sweep coagulation zone was only 18.6%. The effects of remixing on the breakage and regrowth of flocs increased with remixing intensity. In sweep coagulation zone, the settling height and mean settling velocity of the interface between flocs blanket and water were lower for the broken and partly reforming flocs than for those unbroken; Moreover, in flocculation settling and zone settling zones, the instantaneous settling velocity of the interface at the same flocs concentration was also lower for the broken flocs than for those unbroken, but in compression settling zone, the instantaneous settling velocity was the same whether the flocs were broken or not.

  17. Mathematical models of blood coagulation and platelet adhesion: clinical applications.

    PubMed

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

    2007-01-01

    At present, computer-assisted molecular modeling and virtual screening have become effective and widely-used tools for drug design. However, a prerequisite for design and synthesis of a therapeutic agent is determination of a correct target in the metabolic system, which should be either inhibited or stimulated. Solution of this extremely complicated problem can also be assisted by computational methods. This review discusses the use of mathematical models of blood coagulation and platelet-mediated primary hemostasis and thrombosis as cost-effective and time-saving tools in research, clinical practice, and development of new therapeutic agents and biomaterials. We focus on four aspects of their application: 1) efficient diagnostics, i.e. theoretical interpretation of diagnostic data, including sensitivity of various clotting assays to the changes in the coagulation system; 2) elucidation of mechanisms of coagulation disorders (e.g. hemophilias and thrombophilias); 3) exploration of mechanisms of action of therapeutic agents (e.g. recombinant activated factor VII) and planning rational therapeutic strategy; 4) development of biomaterials with non-thrombogenic properties in the design of artificial organs and implantable devices. Accumulation of experimental knowledge about the blood coagulation system and about platelets, combined with impressive increase of computational power, promises rapid development of this field.

  18. Synthetic polyphosphate inhibits endogenous coagulation and platelet aggregation in vitro

    PubMed Central

    Yang, Xiaoyang; Wan, Mengjie; Liang, Ting; Peng, Minyuan; Chen, Fangping

    2017-01-01

    Platelet-derived polyphosphate has previously been indicated to induce coagulation. However, industrially synthesized polyphosphate has been found to have different effects from those of the platelet-derived form. The present study investigated whether synthetic sodium polyphosphate inhibits coagulation using routine coagulation tests and thromboelastography. Synthetic polyphosphate was found to inhibit adenosine diphosphate-, epinephrine-, arachidonic acid-, ristocetin-, thrombin-, oxytocin- and pituitrin-induced platelet aggregation. The effects of synthetic polyphosphate in clotting inhibition were revealed by the analysis of clotting factor activity and platelet aggregation tests. Synthetic polyphosphate may inhibit platelet aggregation by reducing platelet calcium levels, as indicated by the results of flow cytometric analysis and high-throughput fluorescent screening. Furthermore, analysis of thromboxane (TX)B2 by ELISA indicated that synthetic polyphosphate reduces platelet aggregation by inhibiting the TXA2 signaling pathway. In conclusion, synthetic polyphosphate inhibits clotting factor activity and endogenous coagulation by reducing the levels of calcium ions and TXA2 to curb platelet aggregation. PMID:28123708

  19. Nanofiltration based water reclamation from tannery effluent following coagulation pretreatment.

    PubMed

    Dasgupta, J; Mondal, D; Chakraborty, S; Sikder, J; Curcio, S; Arafat, H A

    2015-11-01

    Coagulation-nanofiltration based integrated treatment scheme was employed in the present study to maximize the removal of toxic Cr(VI) species from tannery effluents. The coagulation pretreatment step using aluminium sulphate hexadecahydrate (alum) was optimized by response surface methodology (RSM). A nanofiltration unit was integrated with this coagulation pre-treatment unit and the resulting flux decline and permeate quality were investigated. Herein, the coagulation was conducted under response surface-optimized operating conditions. The hybrid process demonstrated high chromium(VI) removal efficiency over 98%. Besides, fouling of two of the tested nanofiltration membranes (NF1 and NF3) was relatively mitigated after feed pretreatment. Nanofiltration permeation fluxes as high as 80-100L/m(2)h were thereby obtained. The resulting permeate stream quality post nanofiltration (NF3) was found to be suitable for effective reuse in tanneries, keeping the Cr(VI) concentration (0.13mg/L), Biochemical Oxygen Demand (BOD) (65mg/L), Chemical Oxygen Demand (COD) (142mg/L), Total Dissolved Solids (TDS) (108mg/L), Total Solids (TS) (86mg/L) and conductivity levels (14mho/cm) in perspective. The process water reclaiming ability of nanofiltration was thereby substantiated and the effectiveness of the proposed hybrid system was thus affirmed.

  20. Harmonic Motion Microwave Doppler Imaging method for breast tumor detection.

    PubMed

    Top, Can Barıs; Tafreshi, Azadeh Kamali; Gençer, Nevzat G

    2014-01-01

    Harmonic Motion Microwave Doppler Imaging (HMMDI) method is recently proposed as a non-invasive hybrid breast imaging technique for tumor detection. The acquired data depend on acoustic, elastic and electromagnetic properties of the tissue. The potential of the method is analyzed with simulation studies and phantom experiments. In this paper, the results of these studies are summarized. It is shown that HMMDI method has a potential to detect malignancies inside fibro-glandular tissue.